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Sample records for experimental pain models

  1. Modelling concentration-analgesia relationships for morphine to evaluate experimental pain models

    DEFF Research Database (Denmark)

    Sverrisdóttir, Eva; Foster, David John Richard; Upton, Richard Neil

    2015-01-01

    The aim of this study was to develop population pharmacokinetic-pharmacodynamic models for morphine in experimental pain induced by skin heat and muscle pressure, and to evaluate the experimental pain models with regard to assessment of morphine pharmacodynamics. In a randomized, double......-blind, placebo-controlled, crossover study, 39 healthy volunteers received an oral dose of 30 mg morphine hydrochloride or placebo. Non-linear mixed effects modelling was used to describe the plasma concentrations of morphine and metabolites, and the analgesic effect of morphine on experimental pain in skin...... and muscle. Baseline pain metrics varied between individuals and occasions, and were described with interindividual and interoccasion variability. Placebo-response did not change with time. For both pain metrics, morphine effect was proportional to baseline pain and was described with a linear model...

  2. Endogenous opioid antagonism in physiological experimental pain models

    DEFF Research Database (Denmark)

    Werner, Mads U; Pereira, Manuel P; Andersen, Lars Peter H

    2015-01-01

    hyperalgesia models (6 studies), 'pain' models (25 studies), summation models (2 studies), nociceptive reflex models (3 studies) and miscellaneous models (2 studies). A consistent reversal of analgesia by a MOR-antagonist was demonstrated in 10 of the 25 ITP-studies, including stress-induced analgesia and r...... ratings, threshold assessments and somatosensory evoked potentials (SSEP), did not appear consistent in 28 out of 32 'pain' model studies. In conclusion, only in 2 experimental human pain models, i.e., stress-induced analgesia and rTMS, administration of MOR-antagonist demonstrated a consistent effect......Opioid antagonists are pharmacological tools applied as an indirect measure to detect activation of the endogenous opioid system (EOS) in experimental pain models. The objective of this systematic review was to examine the effect of mu-opioid-receptor (MOR) antagonists in placebo-controlled, double...

  3. Human experimental pain models: A review of standardized methods in drug development

    Directory of Open Access Journals (Sweden)

    K. Sunil kumar Reddy

    2012-01-01

    Full Text Available Human experimental pain models are essential in understanding the pain mechanisms and appear to be ideally suited to test analgesic compounds. The challenge that confronts both the clinician and the scientist is to match specific treatments to different pain-generating mechanisms and hence reach a pain treatment tailored to each individual patient. Experimental pain models offer the possibility to explore the pain system under controlled settings. Standardized stimuli of different modalities (i.e., mechanical, thermal, electrical, or chemical can be applied to the skin, muscles, and viscera for a differentiated and comprehensive assessment of various pain pathways and mechanisms. Using a multimodel-multistructure testing, the nociception arising from different body structures can be explored and modulation of specific biomarkers by new and existing analgesic drugs can be profiled. The value of human experimental pain models is to link animal and clinical pain studies, providing new possibilities for designing successful clinical trials. Spontaneous pain, the main compliant of the neuropathic patients, but currently there is no human model available that would mimic chronic pain. Therefore, current human pain models cannot replace patient studies for studying efficacy of analgesic compounds, although being helpful for proof-of-concept studies and dose finding.

  4. Inflammatory pain in experimental burns in man

    DEFF Research Database (Denmark)

    Pedersen, J L

    2000-01-01

    stimuli may be more reproducible. A methodological study also demonstrated that habituation to experimental pain developed as the study proceeded. Habituation is common in experimental pain models, and dividing analgesics and placebo evenly between the study days is one way of eliminating the effects......Human experimental pain models are important tools in pain research. The primary aims of pain research in normal man is 1) to provide insight in pain mechanisms, 2) to provide a rational basis for clinical trials of pain relieving interventions, and 3) to confirm the anti-nociceptive effects...... demonstrated in animal models. Most often clinical pain is due to tissue damage leading to acute inflammation and hyperalgesia, but only few human pain models have examined pain responses in injured tissues. Therefore, models with controlled and reversible tissue trauma are needed. The human burn model...

  5. Translational pain research: evaluating analgesic effect in experimental visceral pain models

    DEFF Research Database (Denmark)

    Olesen, Anne Estrup; Andresen, Trine; Christrup, Lona Louring

    2009-01-01

    Deep visceral pain is frequent and presents major challenges in pain management, since its pathophysiology is still poorly understood. One way to optimize treatment of visceral pain is to improve knowledge of the mechanisms behind the pain and the mode of action of analgesic substances. This can ...... studies and clinical condition in patients suffering from visceral pain, and thus constitute the missing link in translational pain research.......Deep visceral pain is frequent and presents major challenges in pain management, since its pathophysiology is still poorly understood. One way to optimize treatment of visceral pain is to improve knowledge of the mechanisms behind the pain and the mode of action of analgesic substances. This can...... facilitate minimizing the gap between knowledge gained in animal and human clinical studies. Combining experimental pain studies and pharmacokinetic studies can improve understanding of the pharmacokinetic-pharmacodynamic relationship of analgesics and, thus, provide valuable insight into optimal clinical...

  6. Experimental knee pain evoke spreading hyperalgesia and facilitated temporal summation of pain

    DEFF Research Database (Denmark)

    Jørgensen, Tanja Schjødt; Henriksen, Marius; Danneskiold-Samsøe, Bente

    2013-01-01

    OBJECTIVES: This study evaluated the deep-tissue pressure pain sensitivity and temporal summation of pain within and around healthy knees exposed to experimental pain. DESIGN: The study was designed as a randomized crossover trial, with each subject tested on 1 day. SETTING: All tests were carried...... occasions: baseline, immediately after the injection, and when pain had vanished. Assessments sites were located in the peripatellar region, vastus lateralis, and tibialis anterior muscles. RESULTS: The experimental knee pain model demonstrated 1) hyperalgesia to pressure stimulation on the infrapatellar...... fat pad during experimental pain, and 2) facilitated temporal summation of pressure pain at the infrapatellar fat pad and knee-related muscles. CONCLUSION: The increased sensitivity and temporal summation found in this study were exclusive to deep -tissue with no contralateral decreased pain...

  7. Pharmacodynamic Modelling of Placebo and Buprenorphine Effects on Event-Related Potentials in Experimental Pain

    DEFF Research Database (Denmark)

    Juul, Rasmus V; Foster, David J R; Upton, Richard N

    2014-01-01

    The purpose of the study was to investigate placebo and buprenorphine effects on event-related potentials (ERPs) in experimental pain and the potential benefit of population pharmacodynamic modelling in data analysis. Nineteen healthy volunteers received transdermal placebo and buprenorphine...... in a cross-over study. Drug plasma concentrations and ERPs after electrical stimulation at the median nerve with intensity adjusted to pain detection threshold were recorded until 144 hrs after administration. Placebo and concentration-effect models were fitted to data using non-linear mixed......, pharmacodynamic modelling was successfully implemented to allow for placebo and variability correction in ERP of experimental pain. Improved outcome of ERP studies can be expected if variation between subjects and study occasions can be identified and described....

  8. Bone hyperalgesia after mechanical impact stimulation: a human experimental pain model.

    Science.gov (United States)

    Finocchietti, Sara; Graven-Nielsen, Thomas; Arendt-Nielsen, Lars

    2014-12-01

    Hyperalgesia in different musculoskeletal structures including bones is a major clinical problem. An experimental bone hyperalgesia model was developed in the present study. Hyperalgesia was induced by three different weights impacted on the shinbone in 16 healthy male and female subjects. The mechanical impact pain threshold (IPT) was measured as the height from which three weights (165, 330, and 660 g) should be dropped to elicit pain at the shinbone. Temporal summation of pain to repeated impact stimuli was assessed. All these stimuli caused bone hyperalgesia. The pressure pain threshold (PPT) was assessed by a computerized pressure algometer using two different probes (1.0 and 0.5 cm(2)). All parameters were recorded before (0), 24, 72, and 96 h after the initial stimulations. The IPTs were lowest 24 h after hyperalgesia induction for all three weights and the effect lasted up to 72 h (p pain and hyperalgesia model may provide the basis for studying this fundamental mechanism of bone-related hyperalgesia and be used for profiling compounds developed for this target.

  9. Experimental human pain models in gastro-esophageal reflux disease and unexplained chest pain

    Institute of Scientific and Technical Information of China (English)

    Asbj(φ)rn Mohr Drewes; Lars Arendt-Nielsen; Peter Funch-Jensen; Hans Gregersen

    2006-01-01

    Methods related to experimental human pain research aim at activating different nociceptors, evoke pain from different organs and activate specific pathways and mechanisms. The different possibilities for using mechanical, electrical, thermal and chemical methods in visceral pain research are discussed with emphasis of combinations (e.g., the multimodal approach). The methods have been used widely in assessment of pain mechanisms in the esophagus and have contributed to our understanding of the symptoms reported in these patients. Hence abnormal activation and plastic changes of central pain pathways seem to play a major role in the symptoms in some patients with gastro-esophageal reflux disease and in patients with functional chest pain of esophageal origin. These findings may lead to an alternative approach for treatment in patients that does not respond to conventional medical or surgical therapy.

  10. Mechanisms of Osteoarthritic Pain. Studies in Humans and Experimental Models

    Directory of Open Access Journals (Sweden)

    Annett Eitner

    2017-11-01

    Full Text Available Pain due to osteoarthritis (OA is one of the most frequent causes of chronic pain. However, the mechanisms of OA pain are poorly understood. This review addresses the mechanisms which are thought to be involved in OA pain, derived from studies on pain mechanisms in humans and in experimental models of OA. Three areas will be considered, namely local processes in the joint associated with OA pain, neuronal mechanisms involved in OA pain, and general factors which influence OA pain. Except the cartilage all structures of the joints are innervated by nociceptors. Although the hallmark of OA is the degradation of the cartilage, OA joints show multiple structural alterations of cartilage, bone and synovial tissue. In particular synovitis and bone marrow lesions have been proposed to determine OA pain whereas the contribution of the other pathologies to pain generation has been studied less. Concerning the peripheral neuronal mechanisms of OA pain, peripheral nociceptive sensitization was shown, and neuropathic mechanisms may be involved at some stages. Structural changes of joint innervation such as local loss and/or sprouting of nerve fibers were shown. In addition, central sensitization, reduction of descending inhibition, descending excitation and cortical atrophies were observed in OA. The combination of different neuronal mechanisms may define the particular pain phenotype in an OA patient. Among mediators involved in OA pain, nerve growth factor (NGF is in the focus because antibodies against NGF significantly reduce OA pain. Several studies show that neutralization of interleukin-1β and TNF may reduce OA pain. Many patients with OA exhibit comorbidities such as obesity, low grade systemic inflammation and diabetes mellitus. These comorbidities can significantly influence the course of OA, and pain research just began to study the significance of such factors in pain generation. In addition, psychologic and socioeconomic factors may aggravate

  11. Experimental human pain models in gastro-esophageal reflux disease and unexplained chest pain

    Science.gov (United States)

    Drewes, Asbjørn Mohr; Arendt-Nielsen, Lars; Funch-Jensen, Peter; Gregersen, Hans

    2006-01-01

    Methods related to experimental human pain research aim at activating different nociceptors, evoke pain from different organs and activate specific pathways and mechanisms. The different possibilities for using mechanical, electrical, thermal and chemical methods in visceral pain research are discussed with emphasis of combinations (e.g., the multimodal approach). The methods have been used widely in assessment of pain mechanisms in the esophagus and have contributed to our understanding of the symptoms reported in these patients. Hence abnormal activation and plastic changes of central pain pathways seem to play a major role in the symptoms in some patients with gastro-esophageal reflux disease and in patients with functional chest pain of esophageal origin. These findings may lead to an alternative approach for treatment in patients that does not respond to conventional medical or surgical therapy. PMID:16718803

  12. Masseter motor unit recruitment is altered in experimental jaw muscle pain

    NARCIS (Netherlands)

    Minami, I.; Akhter, R.; Albersen, I.; Burger, C.; Whittle, T.; Lobbezoo, F.; Peck, C.C.; Murray, G.M.

    2013-01-01

    Some management strategies for chronic orofacial pain are influenced by models (e.g., Vicious Cycle Theory, Pain Adaptation Model) proposing either excitation or inhibition within a painful muscle. The aim of this study was to determine if experimental painful stimulation of the masseter muscle

  13. Bilateral experimental neck pain reorganize axioscapular muscle coordination and pain sensitivity.

    Science.gov (United States)

    Christensen, S W; Hirata, R P; Graven-Nielsen, T

    2017-04-01

    Neck pain is a large clinical problem where reorganized trunk and axioscapular muscle activities have been hypothesised contributing to pain persistence and pain hypersensitivity. This study investigated the effects of bilateral experimental neck pain on trunk and axioscapular muscle function and pain sensitivity. In 25 healthy volunteers, bilateral experimental neck pain was induced in the splenius capitis muscles by hypertonic saline injections. Isotonic saline was used as control. In sitting, subjects performed slow, fast and slow-resisted unilateral arm movements before, during and after injections. Electromyography (EMG) was recorded from eight shoulder and trunk muscles bilaterally. Pressure pain thresholds (PPTs) were assessed bilaterally at the neck, head and arm. Data were normalized to the before-measures. Compared with control and post measurements, experimental neck pain caused (1) decreased EMG activity of the ipsilateral upper trapezius muscles during all but slow-resisted down movements (p neck pain reorganized axioscapular and trunk muscle activity together with local hyperalgesia and widespread hypoalgesia indicating that acute neck pain immediately affects trunk and axioscapular function which may affect both assessment and treatment. Bilateral clinical neck pain alters axioscapular muscle coordination but only effects of unilateral experimental neck pain has been investigated. Bilateral experimental neck pain causes task-dependent reorganized axioscapular and trunk muscle activity in addition to widespread decrease in pressure pain sensitivity. © 2016 European Pain Federation - EFIC®.

  14. A dyadic analysis of siblings' relationship quality, behavioural responses, and pain experiences during experimental pain.

    Science.gov (United States)

    Schinkel, Meghan G; Chambers, Christine T; Corkum, Penny; Jacques, Sophie

    2018-04-16

    Research on family factors in paediatric pain has primarily focused on parents; the role of siblings has been largely ignored. This study examined whether sibling relationship quality was related to siblings' behaviours during experimental pain, and whether the behaviours of an observing sibling were related to children's pain outcomes. Ninety-two sibling dyads between 8-12 years old completed both observational and questionnaire measures of sibling relationship quality. Children took turns completing the cold pressor task (CPT) in a counterbalanced order with their sibling present. Pain outcomes (intensity, fear, tolerance) were recorded for each sibling, and the behaviour of the observing and participating siblings during the CPT were coded as attending, non-attending, and coping/encouragement. Structural equation modelling, using the actor-partner interdependence model, was conducted to analyse the dyadic data. While participating in the CPT with their sibling present, greater levels of warmth and positivity in the sibling relationship were related to children engaging in more non-attending behaviours and less attending behaviours. Greater levels of attending behaviours by the observing child was related to the sibling having a lower pain tolerance, and greater levels of coping/encouragement behaviours by the observing child was related to the sibling reporting greater pain intensity and fear during the CPT. Children with warmer/positive sibling relationships were more likely to respond to acute pain by shifting the focus away from their pain experience (e.g., through distraction) when a sibling was present. Pain-focused behaviours by an observing sibling are related to greater child pain and fear during experimental pain.

  15. Experimental tooth clenching. A model for studying mechanisms of muscle pain.

    Science.gov (United States)

    Dawson, Andreas

    2013-01-01

    The overall goal of this thesis was to broaden knowledge of pain mechanisms in myofascial temporomandibular disorders (M-TMD). The specific aims were to: Develop a quality assessment tool for experimental bruxism studies (study I). Investigate proprioceptive allodynia after experimental tooth clenching exercises (study II). Evaluate the release of serotonin (5-HT), glutamate, pyruvate, and lactate in healthy subjects (study III) and in patients with M-TMD (study IV), after experimental tooth clenching exercises. In (I), tool development comprised 5 steps: (i) preliminary decisions, (ii) item generation, (iii) face-validity assessment, (iv) reliability and discriminative validity testing, and (v) instrument refinement. After preliminary decisions and a literature review, a list of 52 items to be considered for inclusion in the tool was generated. Eleven experts were invited to participate on the Delphi panel, of which 10 agreed. After four Delphi rounds, 8 items remained and were included in the Quality Assessment Tool for Experimental Bruxism Studies (Qu-ATEBS). Inter-observer reliability was acceptable (k = 0.77), and discriminative validity high (phi coefficient 0.79; P < 0.01). During refinement, 1 item was removed; the final tool comprised 7 items. In (II), 16 healthy females participated in three 60-min sessions, each with 24- and 48-h follow-ups. Participants were randomly assigned to a repetitive experimental tooth clenching task with a clenching level of 10%, 20%, or 40% of maximal voluntary clenching force (MVCF). Pain intensity, fatigue, perceived intensity of vibration (PIV), perceived discomfort (PD), and pressure pain threshold (PPT) were measured throughout. A significant increase in pain intensity and fatigue but not in PD was observed over time. A significant increase in PIV was only observed at 40 min, and PPT decreased significantly over time at 50 and 60 min compared to baseline. In (III), 30 healthy subjects (16 females, and 14 males

  16. Experimental knee pain reduces muscle strength

    DEFF Research Database (Denmark)

    Henriksen, Marius; Mortensen, Sara Rosager; Aaboe, Jens

    2011-01-01

    Pain is the principal symptom in knee pathologies and reduced muscle strength is a common observation among knee patients. However, the relationship between knee joint pain and muscle strength remains to be clarified. This study aimed at investigating the changes in knee muscle strength following...... experimental knee pain in healthy volunteers, and if these changes were associated with the pain intensities. In a crossover study, 18 healthy subjects were tested on 2 different days. Using an isokinetic dynamometer, maximal muscle strength in knee extension and flexion was measured at angular velocities 0....... Knee pain reduced the muscle strength by 5 to 15% compared to the control conditions (P knee extension and flexion at all angular velocities. The reduction in muscle strength was positively correlated to the pain intensity. Experimental knee pain significantly reduced knee extension...

  17. Effects of gabapentin on experimental somatic pain and temporal summation

    DEFF Research Database (Denmark)

    Arendt-Nielsen, Lars; Frøkjaer, Jens Brøndum; Staahl, Camilla

    2007-01-01

    at 2 Hz); (2) stimulus-response function relating pain intensity scores (visual analog scale, VAS) to increasing current intensities for electrical skin and muscle stimuli (single and repeated, determined at baseline); and (3) the pain intensity (VAS) and pain areas after intramuscular injection......, was to examine the effect of a single dose of 1200 mg gabapentin on multi-modal experimental cutaneous and muscle pain models. METHODS: The following pain models were applied: (1) pain thresholds to single and repeated cutaneous and intramuscular electrical stimulation (temporal summation to 5 stimuli delivered...... reduced the area under the pain intensity curve to hypertonic saline injections in the muscle (P = .02); and (3) significantly reduced the area of pain evoked by hypertonic saline (P = .03). CONCLUSIONS: Gabapentin reduces temporal summation of skin stimuli at pain threshold intensities; this may have...

  18. The Animal Model of Spinal Cord Injury as an Experimental Pain Model

    Directory of Open Access Journals (Sweden)

    Aya Nakae

    2011-01-01

    Full Text Available Pain, which remains largely unsolved, is one of the most crucial problems for spinal cord injury patients. Due to sensory problems, as well as motor dysfunctions, spinal cord injury research has proven to be complex and difficult. Furthermore, many types of pain are associated with spinal cord injury, such as neuropathic, visceral, and musculoskeletal pain. Many animal models of spinal cord injury exist to emulate clinical situations, which could help to determine common mechanisms of pathology. However, results can be easily misunderstood and falsely interpreted. Therefore, it is important to fully understand the symptoms of human spinal cord injury, as well as the various spinal cord injury models and the possible pathologies. The present paper summarizes results from animal models of spinal cord injury, as well as the most effective use of these models.

  19. The Animal Model of Spinal Cord Injury as an Experimental Pain Model

    Science.gov (United States)

    Nakae, Aya; Nakai, Kunihiro; Yano, Kenji; Hosokawa, Ko; Shibata, Masahiko; Mashimo, Takashi

    2011-01-01

    Pain, which remains largely unsolved, is one of the most crucial problems for spinal cord injury patients. Due to sensory problems, as well as motor dysfunctions, spinal cord injury research has proven to be complex and difficult. Furthermore, many types of pain are associated with spinal cord injury, such as neuropathic, visceral, and musculoskeletal pain. Many animal models of spinal cord injury exist to emulate clinical situations, which could help to determine common mechanisms of pathology. However, results can be easily misunderstood and falsely interpreted. Therefore, it is important to fully understand the symptoms of human spinal cord injury, as well as the various spinal cord injury models and the possible pathologies. The present paper summarizes results from animal models of spinal cord injury, as well as the most effective use of these models. PMID:21436995

  20. The Animal Model of Spinal Cord Injury as an Experimental Pain Model

    OpenAIRE

    Nakae, Aya; Nakai, Kunihiro; Yano, Kenji; Hosokawa, Ko; Shibata, Masahiko; Mashimo, Takashi

    2011-01-01

    Pain, which remains largely unsolved, is one of the most crucial problems for spinal cord injury patients. Due to sensory problems, as well as motor dysfunctions, spinal cord injury research has proven to be complex and difficult. Furthermore, many types of pain are associated with spinal cord injury, such as neuropathic, visceral, and musculoskeletal pain. Many animal models of spinal cord injury exist to emulate clinical situations, which could help to determine common mechanisms of patholo...

  1. Periodontal CGRP contributes to orofacial pain following experimental tooth movement in rats.

    Science.gov (United States)

    Long, Hu; Liao, Lina; Gao, Meiya; Ma, Wenqiang; Zhou, Yang; Jian, Fan; Wang, Yan; Lai, Wenli

    2015-08-01

    Calcitonin-related gene peptide (CGRP) plays an important role in orofacial inflammatory pain. The aim of this study was to determine whether periodontal CGRP contributes to orofacial pain induced by experimental tooth movement in rats. Male Sprague-Dawley rats were used in this study. Closed coil springs were used to deliver forces. Rats were euthanized on 0d, 1d, 3d, 5d, 7d, and 14d following experimental tooth movement. Then, alveolar bones were obtained for immunostaining of periodontal tissues against CGRP. Two hours prior to euthanasia on each day, orofacial pain levels were assessed through rat grimace scale. CGRP and olcegepant (CGRP receptor antagonist) were injected into periodontal tissues to verify the roles of periodontal CGRP in orofacial pain induced by experimental tooth movement. Periodontal CGRP expression levels and orofacial pain levels were elevated on 1d, 3d, 5d, and 7d following experimental tooth movement. The two indices were significantly correlated with each other and fitted into a dose-response model. Periodontal administration of CGRP could elevate periodontal CGRP expressions and exacerbate orofacial pain. Moreover, olcegepant administration could decrease periodontal CGRP expressions and alleviate orofacial pain. Therefore, periodontal CGRP plays an important role in pain transmission and modulation following experimental tooth movement. We suggest that it may participate in a positive feedback aiming to amplify orofacial pain signals. Copyright © 2015 Elsevier B.V. All rights reserved.

  2. Masseter motor unit recruitment is altered in experimental jaw muscle pain.

    Science.gov (United States)

    Minami, I; Akhter, R; Albersen, I; Burger, C; Whittle, T; Lobbezoo, F; Peck, C C; Murray, G M

    2013-02-01

    Some management strategies for chronic orofacial pain are influenced by models (e.g., Vicious Cycle Theory, Pain Adaptation Model) proposing either excitation or inhibition within a painful muscle. The aim of this study was to determine if experimental painful stimulation of the masseter muscle resulted in only increases or only decreases in masseter activity. Recordings of single-motor-unit (SMU, basic functional unit of muscle) activity were made from the right masseters of 10 asymptomatic participants during biting trials at the same force level and direction under infusion into the masseter of isotonic saline (no-pain condition), and in another block of biting trials on the same day, with 5% hypertonic saline (pain condition). Of the 36 SMUs studied, 2 SMUs exhibited a significant (p units were present only during the no-pain block and 10 units during the pain block only. The findings suggest that, rather than only excitation or only inhibition within a painful muscle, a re-organization of activity occurs, with increases and decreases occurring within the painful muscle. This suggests the need to re-assess management strategies based on models that propose uniform effects of pain on motor activity.

  3. Adaptations in the gait pattern with experimental hamstring pain

    DEFF Research Database (Denmark)

    Henriksen, M; Mortensen, Sara Rosager; Aaboe, J

    2011-01-01

    and little attention has been given to how pain in other muscles affects functional movement. The purpose of this study was to investigate the changes in the gait patterns of healthy subjects that occur during experimental muscle pain in the biceps femoris. In a cross-over study design, 14 healthy volunteers...... underwent EMG assisted 3D gait analyses before, during and after experimental biceps femoris pain induced by intramuscular injections of hypertonic saline. Isotonic saline injections were administered as a non-painful control. The experimental biceps femoris pain led to reductions in hip extensor moments......, knee flexor and lateral rotator moments. No changes in lower extremity kinematics and EMG activity in any of the recorded muscles were observed. It is concluded that experimental muscle pain in the biceps femoris leads to changes in the gait pattern in agreement with unloading of the painful muscle...

  4. The genetic influence on the cortical processing of experimental pain and the moderating effect of pain status.

    Directory of Open Access Journals (Sweden)

    Helen Vossen

    Full Text Available BACKGROUND: Research suggests that the COMT Val(158Met, BDNF Val(66Met and OPRM1 A(118G polymorphisms moderate the experience of pain. In order to obtain experimental confirmation and extension of findings, cortical processing of experimentally-induced pain was used. METHOD: A sample of 78 individuals with chronic low back pain complaints and 37 healthy controls underwent EEG registration. Event-Related Potentials were measured in response to electrical nociceptive stimuli and moderation by COMT Val(158Met, BDNF Val(66Met and OPRM1 A(118G polymorphisms was assessed. RESULTS: Genetic variation did not have a direct effect on cortical processing of experimental pain. However, genetic effects (COMT Val(158Met and BDNF Val(66Met on experimental pain were moderated by the presence of chronic pain. In the presence of chronic pain, the COMT Met allele and the BDNF Met allele augmented cortical pain processing, whilst reducing pain processing in pain-free controls. No significant effects were found concerning the OPRM1 A(118G polymorphism. CONCLUSIONS: The current study suggests that chronic experience of pain enhances genetic sensitivity to experimentally induced mildly painful stimuli, possibly through a process of epigenetic modification.

  5. Prediction of postoperative pain: a systematic review of predictive experimental pain studies

    DEFF Research Database (Denmark)

    Werner, Mads Utke; Mjöbo, Helena N; Nielsen, Per R

    2010-01-01

    Quantitative testing of a patient's basal pain perception before surgery has the potential to be of clinical value if it can accurately predict the magnitude of pain and requirement of analgesics after surgery. This review includes 14 studies that have investigated the correlation between...... preoperative responses to experimental pain stimuli and clinical postoperative pain and demonstrates that the preoperative pain tests may predict 4-54% of the variance in postoperative pain experience depending on the stimulation methods and the test paradigm used. The predictive strength is much higher than...

  6. Effects of ethnicity and gender role expectations of pain on experimental pain: a cross-cultural study.

    Science.gov (United States)

    Alabas, O A; Tashani, O A; Johnson, M I

    2013-05-01

    Gender role expectations of pain (GREP) have been shown to mediate sex differences in experimental pain. Few studies have investigated the role of ethnicity in shaping GREP. The aim of this study was to examine interactions between ethnicity and GREP on experimentally induced pressure and ischaemic pain in Libyan and white British students in their respective countries. Libyan (n = 124) and white British (n = 51) students completed a GREP questionnaire and their response to experimental pain was measured. Blunt pressure pain threshold (PPT) was measured over the 1st interosseous muscle using algometry. Pain intensity and pain unpleasantness (100 mm visual analogue scale) were measured at 1-min intervals during a submaximal effort tourniquet test on the forearm. Multivariate analysis of variance detected significant effects for Sex and Ethnicity on pain measurements. Men had higher PPTs than women (p 0.05). Libyan participants had higher pain intensity (p < 0.01) and pain unpleasantness (p < 0.05) ratings compared with white British participants. There were effects for Sex and Ethnicity for all GREP dimensions. Libyan participants exhibited stronger stereotypical views in GREP than white British participants (p < 0.001). GREP was the mediator of sex but not ethnic differences in pain report, suggesting that gender stereotypical attitudes to pain account for differences in pain expression between men and women. © 2012 European Federation of International Association for the Study of Pain Chapters.

  7. Dose-specific effects of transcutaneous electrical nerve stimulation (TENS) on experimental pain: a systematic review.

    Science.gov (United States)

    Claydon, Leica S; Chesterton, Linda S; Barlas, Panos; Sim, Julius

    2011-09-01

    To determine the hypoalgesic effects of transcutaneous electrical nerve stimulation (TENS) parameter combinations on experimental models in healthy humans. Searches were performed using the electronic databases Ovid MEDLINE, CINAHL, AMED, and Web of Science (from inception to December 2009). Manual searches of journals and reference lists of retrieved trials were also performed. Randomized controlled trials (RCTs) were included in the review if they compared the hypoalgesic effect of TENS relative with placebo and control, using an experimental pain model in healthy human participants. Two reviewers independently selected the trials, assessed their methodologic quality and extracted data. Forty-three RCTs were eligible for inclusion. A best evidence synthesis revealed: Overall "conflicting" (inconsistent findings in multiple RCTs) evidence of TENS efficacy on experimental pain irrespective of TENS parameters used. Overall intense TENS has "moderate" evidence of efficacy (1 high-quality and 2 low-quality trials). Conventional TENS has overall conflicting evidence of efficacy, this is derived from "strong" evidence of efficacy (generally consistent findings in multiple high-quality RCTs) on pressure pain but strong evidence of inefficacy on other pain models. "Limited" evidence (positive findings from 1 RCT) of hypoalgesia exists for some novel parameters. Low-intensity, low-frequency, local TENS has strong evidence of inefficacy. Inappropriate TENS (using "barely perceptible" intensities) has moderate evidence of inefficacy. The level of hypoalgesic efficacy of TENS is clearly dependent on TENS parameter combination selection (defined in terms of intensity, frequency, and stimulation site) and experimental pain model. Future clinical RCTs may consider these TENS dose responses.

  8. Healthy volunteers can be phenotyped using cutaneous sensitization pain models

    DEFF Research Database (Denmark)

    Werner, Mads U; Petersen, Karin; Rowbotham, Michael C

    2013-01-01

    Human experimental pain models leading to development of secondary hyperalgesia are used to estimate efficacy of analgesics and antihyperalgesics. The ability to develop an area of secondary hyperalgesia varies substantially between subjects, but little is known about the agreement following repe...... repeated measurements. The aim of this study was to determine if the areas of secondary hyperalgesia were consistently robust to be useful for phenotyping subjects, based on their pattern of sensitization by the heat pain models.......Human experimental pain models leading to development of secondary hyperalgesia are used to estimate efficacy of analgesics and antihyperalgesics. The ability to develop an area of secondary hyperalgesia varies substantially between subjects, but little is known about the agreement following...

  9. Patterns of experimentally induced pain in pericranial muscles

    DEFF Research Database (Denmark)

    Schmidt-Hansen, Peter Thede; Svensson, Peter; Jensen, Troels Staehelin

    2006-01-01

    into the masseter muscle (anova: P pain areas (anova: P cervically innervated muscles had significantly different patterns of spread and referral of pain according to trigeminally vs....... cervically innervated dermatomes (P pain patterns and pain sensitivity in different craniofacial muscles in healthy volunteers, which may be of importance for further research on different craniofacial pain conditions.......Nociceptive mechanisms in the craniofacial muscle tissue are poorly understood. The pain pattern in individual pericranial muscles has not been described before. Experimental muscle pain was induced by standardized infusions of 0.2 ml 1 m hypertonic saline into six craniofacial muscles (masseter...

  10. The influence of experimentally induced pain on shoulder muscle activity

    DEFF Research Database (Denmark)

    Diederichsen, L.P.; Winther, A.; Dyhre-Poulsen, P.

    2009-01-01

    healthy men (range 22-27 years), with no history of shoulder or cervical problems, were included in the study. Pain was induced by 5% hypertonic saline injections into the supraspinatus muscle or subacromially. Seated in a shoulder machine, subjects performed standardized concentric abduction (0A degrees......Muscle function is altered in painful shoulder conditions. However, the influence of shoulder pain on muscle coordination of the shoulder has not been fully clarified. The aim of the present study was to examine the effect of experimentally induced shoulder pain on shoulder muscle function. Eleven...... muscles. EMG was recorded before pain, during pain and after pain had subsided and pain intensity was continuously scored on a visual analog scale (VAS). During abduction, experimentally induced pain in the supraspinatus muscle caused a significant decrease in activity of the anterior deltoid, upper...

  11. Effect of experimental chewing on masticatory muscle pain onset

    Directory of Open Access Journals (Sweden)

    Paulo César Rodrigues Conti

    2011-02-01

    Full Text Available OBJECTIVES: To evaluate the effect of a chewing exercise on pain intensity and pressure-pain threshold in patients with myofascial pain. METHODS: Twenty-nine consecutive women diagnosed with myofascial pain (MFP according to the Research Diagnostic Criteria comprised the experimental group and 15 healthy age-matched female were used as controls. Subjects were asked to chew a gum stick for 9 min and to stay at rest for another 9 min afterwards. Pain intensity was rated on a visual analog scale (VAS every 3 min. At 0, 9 and 18 min, the pressure-pain threshold (PPT was measured bilaterally on the masseter and the anterior, medium, and posterior temporalis muscles. RESULTS: Patients with myofascial pain reported increase (76% and no change (24% on the pain intensity measured with the VAS. A reduction of the PPT at all muscular sites after the exercise and a non-significant recovery after rest were also observed. CONCLUSION: The following conclusions can be drawn: 1. there are at least two subtypes of patients with myofascial pain that respond differently to experimental chewing; 2. the chewing protocol had an adequate discriminative ability in distinguishing patients with myofascial pain from healthy controls.

  12. Manipulation of pain catastrophizing: An experimental study of healthy participants

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    Joel E Bialosky

    2008-11-01

    Full Text Available Joel E Bialosky1*, Adam T Hirsh2,3, Michael E Robinson2,3, Steven Z George1,3*1Department of Physical Therapy; 2Department of Clinical and Health Psychology; 3Center for Pain Research and Behavioral Health, University of Florida, Gainesville, Florida, USAAbstract: Pain catastrophizing is associated with the pain experience; however, causation has not been established. Studies which specifically manipulate catastrophizing are necessary to establish causation. The present study enrolled 100 healthy individuals. Participants were randomly assigned to repeat a positive, neutral, or one of three catastrophizing statements during a cold pressor task (CPT. Outcome measures of pain tolerance and pain intensity were recorded. No change was noted in catastrophizing immediately following the CPT (F(1,84 = 0.10, p = 0.75, partial η2 < 0.01 independent of group assignment (F(4,84 = 0.78, p = 0.54, partial η2 = 0.04. Pain tolerance (F(4 = 0.67, p = 0.62, partial η2 = 0.03 and pain intensity (F(4 = 0.73, p = 0.58, partial η2 = 0.03 did not differ by group. This study suggests catastrophizing may be difficult to manipulate through experimental pain procedures and repetition of specific catastrophizing statements was not sufficient to change levels of catastrophizing. Additionally, pain tolerance and pain intensity did not differ by group assignment. This study has implications for future studies attempting to experimentally manipulate pain catastrophizing.Keywords: pain, catastrophizing, experimental, cold pressor task, pain catastrophizing scale

  13. Characterization of a novel model of tonic heat pain stimulation in healthy volunteers.

    Science.gov (United States)

    Naert, Arne L G; Kehlet, Henrik; Kupers, Ron

    2008-08-15

    The vast majority of the experimental pain studies have used acute, phasic heat stimuli to investigate the neurobiological mechanisms of pain. However, the validity of these models for understanding clinical forms of pain is questionable. We here describe the characteristics of a model of prolonged tonic heat pain stimulation and compared the responses on this test with other measures of pain. In 58 normal volunteers, we applied a 7-min lasting contact heat stimulation of 47 degrees C to the upper leg while participants constantly rated their pain. Average pain rating during the 7-min period was 6.2+/-0.4, females scoring higher than men (7.4+/-0.5 vs. 5.2+/-0.5; pPain ratings showed a steady increase during the first half of the stimulation period after which they stabilized. A strong interindividual variability was observed in the time profiles of the pain ratings over the course of the 7-min stimulation period. The model showed a good test-retest reproducibility. Tonic heat pain ratings only correlated moderately with the pain threshold while stronger correlations were observed with pain tolerance and ratings of suprathreshold phasic heat pain. We conclude that the tonic heat model is a suitable model that can be applied without excessive discomfort in the majority of subjects and offers a valuable addition to the armamentarium of experimental pain models. The model can be particularly suitable for brain imaging receptor binding studies which require long stimulation periods.

  14. Vicarious pain experiences while observing another in pain: an experimental approach

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    Sophie eVandenbroucke

    2013-06-01

    Full Text Available Objective: This study aimed at developing an experimental paradigm to assess vicarious pain experiences. We further explored the putative moderating role of observer’s characteristics such as hypervigilance for pain and dispositional empathy. Methods: Two experiments are reported using a similar procedure. Undergraduate students were selected based upon whether they reported vicarious pain in daily life, and categorized into a pain responder group or a comparison group. Participants were presented a series of videos showing hands being pricked whilst receiving occasionally pricking (electrocutaneous stimuli themselves. In congruent trials, pricking and visual stimuli were applied to the same spatial location. In incongruent trials, pricking and visual stimuli were in the opposite spatial location. Participants were required to report on which location they felt a pricking sensation. Of primary interest was the effect of viewing another in pain upon vicarious pain errors, i.e., the number of trials in which an illusionary sensation was reported. Furthermore, we explored the effect of individual differences in hypervigilance to pain, dispositional empathy and the rubber hand illusion (RHI upon vicarious pain errors. Results: Results of both experiments indicated that the number of vicarious pain errors was overall low. In line with expectations, the number of vicarious pain errors was higher in the pain responder group than in the comparison group. Self-reported hypervigilance for pain lowered the probability of reporting vicarious pain errors in the pain responder group, but dispositional empathy and the RHI did not. Conclusion: Our paradigm allows measuring vicarious pain experiences in students. However, the prevalence of vicarious experiences of pain is low, and only a small percentage of participants display the phenomenon. It remains however unknown which variables affect its occurrence.

  15. Hemorrhoids: an experimental model in monkeys

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    Plapler Hélio

    2006-01-01

    Full Text Available PURPOSE: Hemorrhoids are a matter of concern due to a painful outcome. We describe a simple, easy and reliable experimental model to produce hemorrhoids in monkeys. METHODS: 14 monkeys (Cebus apella were used. After general anesthesia, hemorrhoids were induced by ligation of the inferior hemorrhoidal vein, which is very alike to humans. The vein was located through a perianal incision, dissected and ligated with a 3-0 vicryl. The skin was sutured with a 4-0 catgut thread. Animals were kept in appropriate cages and evaluated daily. RESULTS: Nine days later there were hemorrhoidal piles in the anus in fifty percent (50% of the animals. Outcome was unremarkable. There was no bleeding and all animals showed no signs of pain or suffering. CONCLUSION: This is an affordable and reliable experimental model to induce hemorrhoids for experimental studies.

  16. IL17 Mediates Pelvic Pain in Experimental Autoimmune Prostatitis (EAP.

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    Stephen F Murphy

    Full Text Available Chronic pelvic pain syndrome (CPPS is the most common form of prostatitis, accounting for 90-95% of all diagnoses. It is a complex multi-symptom syndrome with unknown etiology and limited effective treatments. Previous investigations highlight roles for inflammatory mediators in disease progression by correlating levels of cytokines and chemokines with patient reported symptom scores. It is hypothesized that alteration of adaptive immune mechanisms results in autoimmunity and subsequent development of pain. Mouse models of CPPS have been developed to delineate these immune mechanisms driving pain in humans. Using the experimental autoimmune prostatitis (EAP in C57BL/6 mice model of CPPS we examined the role of CD4+T-cell subsets in the development and maintenance of prostate pain, by tactile allodynia behavioral testing and flow cytometry. In tandem with increased CD4+IL17A+ T-cells upon EAP induction, prophylactic treatment with an anti-IL17 antibody one-day prior to EAP induction prevented the onset of pelvic pain. Therapeutic blockade of IL17 did not reverse pain symptoms indicating that IL17 is essential for development but not maintenance of chronic pain in EAP. Furthermore we identified a cytokine, IL7, to be associated with increased symptom severity in CPPS patients and is increased in patient prostatic secretions and the prostates of EAP mice. IL7 is fundamental to development of IL17 producing cells and plays a role in maturation of auto-reactive T-cells, it is also associated with autoimmune disorders including multiple sclerosis and type-1 diabetes. More recently a growing body of research has pointed to IL17's role in development of neuropathic and chronic pain. This report presents novel data on the role of CD4+IL17+ T-cells in development and maintenance of pain in EAP and CPPS.

  17. IL17 Mediates Pelvic Pain in Experimental Autoimmune Prostatitis (EAP).

    Science.gov (United States)

    Murphy, Stephen F; Schaeffer, Anthony J; Done, Joseph; Wong, Larry; Bell-Cohn, Ashlee; Roman, Kenny; Cashy, John; Ohlhausen, Michelle; Thumbikat, Praveen

    2015-01-01

    Chronic pelvic pain syndrome (CPPS) is the most common form of prostatitis, accounting for 90-95% of all diagnoses. It is a complex multi-symptom syndrome with unknown etiology and limited effective treatments. Previous investigations highlight roles for inflammatory mediators in disease progression by correlating levels of cytokines and chemokines with patient reported symptom scores. It is hypothesized that alteration of adaptive immune mechanisms results in autoimmunity and subsequent development of pain. Mouse models of CPPS have been developed to delineate these immune mechanisms driving pain in humans. Using the experimental autoimmune prostatitis (EAP) in C57BL/6 mice model of CPPS we examined the role of CD4+T-cell subsets in the development and maintenance of prostate pain, by tactile allodynia behavioral testing and flow cytometry. In tandem with increased CD4+IL17A+ T-cells upon EAP induction, prophylactic treatment with an anti-IL17 antibody one-day prior to EAP induction prevented the onset of pelvic pain. Therapeutic blockade of IL17 did not reverse pain symptoms indicating that IL17 is essential for development but not maintenance of chronic pain in EAP. Furthermore we identified a cytokine, IL7, to be associated with increased symptom severity in CPPS patients and is increased in patient prostatic secretions and the prostates of EAP mice. IL7 is fundamental to development of IL17 producing cells and plays a role in maturation of auto-reactive T-cells, it is also associated with autoimmune disorders including multiple sclerosis and type-1 diabetes. More recently a growing body of research has pointed to IL17's role in development of neuropathic and chronic pain. This report presents novel data on the role of CD4+IL17+ T-cells in development and maintenance of pain in EAP and CPPS.

  18. Experimental knee pain impairs submaximal force steadiness in isometric, eccentric, and concentric muscle actions.

    Science.gov (United States)

    Rice, David A; McNair, Peter J; Lewis, Gwyn N; Mannion, Jamie

    2015-09-12

    Populations with knee joint damage, including arthritis, have noted impairments in the regulation of submaximal muscle force. It is difficult to determine the exact cause of such impairments given the joint pathology and associated neuromuscular adaptations. Experimental pain models that have been used to isolate the effects of pain on muscle force regulation have shown impaired force steadiness during acute pain. However, few studies have examined force regulation during dynamic contractions, and these findings have been inconsistent. The goal of the current study was to examine the effect of experimental knee joint pain on submaximal quadriceps force regulation during isometric and dynamic contractions. The study involved fifteen healthy participants. Participants were seated in an isokinetic dynamometer. Knee extensor force matching tasks were completed in isometric, eccentric, and concentric muscle contraction conditions. The target force was set to 10 % of maximum for each contraction type. Hypertonic saline was then injected into the infrapatella fat pad to generate acute joint pain. The force matching tasks were repeated during pain and once more 5 min after pain had subsided. Hypertonic saline resulted in knee pain with an average peak pain rating of 5.5 ± 2.1 (0-10 scale) that lasted for 18 ± 4 mins. Force steadiness significantly reduced during pain across all three muscle contraction conditions. There was a trend to increased force matching error during pain but this was not significant. Experimental knee pain leads to impaired quadriceps force steadiness during isometric, eccentric, and concentric contractions, providing further evidence that joint pain directly affects motor performance. Given the established relationship between submaximal muscle force steadiness and function, such an effect may be detrimental to the performance of tasks in daily life. In order to restore motor performance in people with painful arthritic conditions of the

  19. Experimental quadriceps muscle pain impairs knee joint control during walking

    DEFF Research Database (Denmark)

    Henriksen, Marius; Alkjaer, Tine; Lund, Hans

    2007-01-01

    Pain is a cardinal symptom in musculoskeletal diseases involving the knee joint, and aberrant movement patterns and motor control strategies are often present in these patients. However, the underlying neuromuscular mechanisms linking pain to movement and motor control are unclear. To investigate...... the functional significance of muscle pain on knee joint control during walking, three-dimensional gait analyses were performed before, during, and after experimentally induced muscle pain by means of intramuscular injections of hypertonic saline (5.8%) into vastus medialis (VM) muscle of 20 healthy subjects....... Isotonic saline (0.9%) was used as control. Surface electromyography (EMG) recordings of VM, vastus lateralis (VL), biceps femoris, and semitendinosus muscles were synchronized with the gait analyses. During experimental muscle pain, the loading response phase peak knee extensor moments were attenuated...

  20. Motor responses to experimental Achilles tendon pain

    DEFF Research Database (Denmark)

    Henriksen, Marius; Aaboe, Jens; Graven-Nielsen, Thomas

    2011-01-01

    of the exercise are affected by Achilles tendon pain. Objective The authors aimed to determine the effects of experimental Achilles tendon pain on motor function during one-legged weight bearing ankle plantar and dorsal flexion exercises. Methods In a crossover study, with 16 healthy subjects tested on two......Background Achilles tendinopathies are characterised by pain and reduced function, and heavy-load exercises have been shown to be effective in the treatment of painful chronic Achilles tendinopathies. However, basic information is needed on how the biomechanics and neuromuscular control...... different days separated by 1 week, three-dimensional ground reaction forces, ankle joint kinematics and surface electromyography (EMG) of the lower leg muscles were recorded during one-legged full weight-bearing ankle plantar (concentric) and dorsal (eccentric) flexion exercises. Measurements were done...

  1. Differential effects of repeated low dose treatment with the cannabinoid agonist WIN 55,212-2 in experimental models of bone cancer pain and neuropathic pain

    DEFF Research Database (Denmark)

    Hald, Andreas; Ding, Ming; Egerod, Kristoffer Lihme

    2008-01-01

    Pain due to bone malignancies is one of the most difficult types of cancer pain to fully control and may further decrease the patients' quality of life. Animal models of chronic pain conditions resulting from peripheral inflammatory reactions or nerve injuries are responsive to treatment with can......Pain due to bone malignancies is one of the most difficult types of cancer pain to fully control and may further decrease the patients' quality of life. Animal models of chronic pain conditions resulting from peripheral inflammatory reactions or nerve injuries are responsive to treatment...... with cannabinoid agonists. However, the use of cannabinoid agonists in humans may be hampered by CNS related side effects and development of tolerance. In the present study, we investigated the effect of repeated low dose administration of the synthetic cannabinoid agonist WIN 55,212-2 on bone cancer pain...... and neuropathic pain in mice. In addition, we investigated the development of CNS related side effects and tolerance. We found that 0.5 mg/kg/day for 18 days reduced pain related behavior and expression of spinal glial fibrillary acidic protein in the bone cancer pain model but not in the neuropathic pain model...

  2. Modelling the PKPD of oxycodone in experimental pain - impact of opioid receptor polymorphisms

    DEFF Research Database (Denmark)

    Olsen, Rasmus; Foster, David J R; Upton, Richard N

    2016-01-01

    BACKGROUND: Polymorphisms in the opioid receptor genes may affect the pharmacodynamics (PD) of oxycodone and be part of the reason behind the diversity in clinical response. The aim of the analysis was to model the exposure-response profile of oxycodone for three different pain variables and search...... for genetic covariates. Model simulations were used to predict how population and effect-size impact the power to detect clinical significant SNPs. METHOD: The population pharmacokinetic-pharmacodynamic (PKPD) model of oral single-dosed oxycodone was based on pooled data from three published studies...... in healthy volunteers. Pain tolerance data from muscle pressure (n=36), visceral pressure (n=54) and skin pinch (n=34) were included. Genetic associations with 18 opioid-receptor SNPs were explored using a stepwise covariate approach. Model simulations were performed using the estimated model parameters...

  3. Functional resonance magnetic imaging (fMRI) in adolescents with idiopathic musculoskeletal pain: a paradigm of experimental pain

    OpenAIRE

    Molina, Juliana; Amaro, Edson; da Rocha, Liana Guerra Sanches; Jorge, Liliana; Santos, Flavia Heloisa; Len, Claudio A.

    2017-01-01

    Background Studies on functional magnetic resonance imaging (fMRI) have shown that adults with musculoskeletal pain syndromes tolerate smaller amount of pressure (pain) as well as differences in brain activation patterns in areas related to pain.The objective of this study was to evaluate, through fMRI, the brain activation in adolescents with idiopathic musculoskeletal pain (IMP) while performing an experimental paradigm of pain. Methods The study included 10 consecutive adolescents with idi...

  4. Pain and executive functions: A unique relationship between Stroop task and experimentally induced pain

    NARCIS (Netherlands)

    Bjekic, J.; Zivanovic, M.; Puric, D.; Oosterman, J.M.; Filipovic, S.R.

    2018-01-01

    There is a growing body of evidence that a higher level of cognitive inhibition is associated with lower experimental pain sensitivity. However, a systematic examination of the association between executive functions, which include not only inhibition but also updating and shifting, and experimental

  5. The contribution of spinal glial cells to chronic pain behaviour in the monosodium iodoacetate model of osteoarthritic pain

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    Sagar Devi

    2011-11-01

    Full Text Available Abstract Background Clinical studies of osteoarthritis (OA suggest central sensitization may contribute to the chronic pain experienced. This preclinical study used the monosodium iodoacetate (MIA model of OA joint pain to investigate the potential contribution of spinal sensitization, in particular spinal glial cell activation, to pain behaviour in this model. Experimental OA was induced in the rat by the intra-articular injection of MIA and pain behaviour (change in weight bearing and distal allodynia was assessed. Spinal cord microglia (Iba1 staining and astrocyte (GFAP immunofluorescence activation were measured at 7, 14 and 28 days post MIA-treatment. The effects of two known inhibitors of glial activation, nimesulide and minocycline, on pain behaviour and activation of microglia and astrocytes were assessed. Results Seven days following intra-articular injection of MIA, microglia in the ipsilateral spinal cord were activated (p Conclusions Here we provide evidence for a contribution of spinal glial cells to pain behaviour, in particular distal allodynia, in this model of osteoarthritic pain. Our data suggest there is a potential role of glial cells in the central sensitization associated with OA, which may provide a novel analgesic target for the treatment of OA pain.

  6. Identifying experimental methods to determine the effect of pain on attention: a review of pain, caffeine, alcohol and nicotine studies.

    Science.gov (United States)

    Moore, David J; Keogh, Edmund; Eccleston, Christopher

    2009-12-01

    To review published studies of the effects that pain and common psychopharmacological substances have on the attentional performance of healthy adults. To identify which attentional tasks have the greatest potential to investigate the effect of pain on attention and provide recommendations for future research. A search was conducted for reports of experimental studies of attention in the context of pain. This was supplemented with studies on attention and caffeine, nicotine and alcohol. Studies were included if they used a healthy adult sample, used experimental or quasi-experimental methods, were relevant to the study of attention or interruption of pain and/or examined the acute effects of a substance on attention. Thirty-two papers, with 49 different experimental studies were identified (12 pain, 21 nicotine, 7 caffeine, 9 alcohol). Fourteen different tasks were reviewed across six domains of attention. The most promising measures of attention were the continuous performance task, flanker task, endogenous pre-cuing task, n-back task, inhibition task and dual task. There are reliable tasks that could be used to determine the effects of pain on attention. Future research is required that develops the utility of these tasks to improve our understanding of the effects pain and analgesia have on attentional performance. Copyright (c) 2009 John Wiley & Sons, Ltd.

  7. Nonpainful wide-area compression inhibits experimental pain.

    Science.gov (United States)

    Honigman, Liat; Bar-Bachar, Ofrit; Yarnitsky, David; Sprecher, Elliot; Granovsky, Yelena

    2016-09-01

    Compression therapy, a well-recognized treatment for lymphoedema and venous disorders, pressurizes limbs and generates massive non-noxious afferent sensory barrages. The aim of this study was to study whether such afferent activity has an analgesic effect when applied on the lower limbs, hypothesizing that larger compression areas will induce stronger analgesic effects, and whether this effect correlates with conditioned pain modulation (CPM). Thirty young healthy subjects received painful heat and pressure stimuli (47°C for 30 seconds, forearm; 300 kPa for 15 seconds, wrist) before and during 3 compression protocols of either SMALL (up to ankles), MEDIUM (up to knees), or LARGE (up to hips) compression areas. Conditioned pain modulation (heat pain conditioned by noxious cold water) was tested before and after each compression protocol. The LARGE protocol induced more analgesia for heat than the SMALL protocol (P < 0.001). The analgesic effect interacted with gender (P = 0.015). The LARGE protocol was more efficient for females, whereas the MEDIUM protocol was more efficient for males. Pressure pain was reduced by all protocols (P < 0.001) with no differences between protocols and no gender effect. Conditioned pain modulation was more efficient than the compression-induced analgesia. For the LARGE protocol, precompression CPM efficiency positively correlated with compression-induced analgesia. Large body area compression exerts an area-dependent analgesic effect on experimental pain stimuli. The observed correlation with pain inhibition in response to robust non-noxious sensory stimulation may suggest that compression therapy shares similar mechanisms with inhibitory pain modulation assessed through CPM.

  8. Evaluation of anti-hyperalgesic and analgesic effects of two benzodiazepines in human experimental pain: a randomized placebo-controlled study.

    Directory of Open Access Journals (Sweden)

    Pascal H Vuilleumier

    Full Text Available Compounds that act on GABA-receptors produce anti-hyperalgesia in animal models, but little is known on their effects in humans. The aim of this study was to explore the potential usefulness of GABA-agonism for the control of pain in humans. Two agonists at the benzodiazepine-binding site of GABAA-receptors (clobazam and clonazepam were studied using multiple experimental pain tests. Positive results would support further investigation of GABA agonism for the control of clinical pain.In a randomized double-blind crossover design, 16 healthy male volunteers received clobazam 20 mg, clonazepam 1 mg and tolterodine 1 mg (active placebo. The area of static hyperalgesia after intradermal capsaicin injection was the primary endpoint. Secondary endpoints were: area of dynamic hyperalgesia, response to von Frey hair stimulation, pressure pain thresholds, conditioned pain modulation, cutaneous and intramuscular electrical pain thresholds (1, 5 and 20 repeated stimulation, and pain during cuff algometry.For the primary endpoint, an increase in the area of static hyperalgesia was observed after administration of placebo (p<0.001, but not after clobazam and clonazepam. Results suggestive for an anti-hyperalgesic effect of the benzodiazepines were obtained with all three intramuscular pain models and with cuff algometry. No effect could be detected with the other pain models employed.Collectively, the results are suggestive for a possible anti-hyperalgesic effect of drugs acting at the GABAA-receptors in humans, particularly in models of secondary hyperalgesia and deep pain. The findings are not conclusive, but support further clinical research on pain modulation by GABAergic drugs. Because of the partial results, future research should focus on compounds acting selectively on subunits of the GABA complex, which may allow the achievement of higher receptor occupancy than unselective drugs. Our data also provide information on the most suitable experimental

  9. A human experimental model of episodic pain

    DEFF Research Database (Denmark)

    Petrini, Laura; Hennings, Kristian; Li, Xi

    2014-01-01

    (VRS). Physiological (blood flow and axon flare reflex), psychophysical (perception threshold and verbal pain ratings) and electrophysiological (128 channels recorded somatosensory evoked potential (SEP)) measurements were recorded. The stimulation evoked a visible axon flare reflex and caused...

  10. The Modulation of Pain by Circadian and Sleep-Dependent Processes: A Review of the Experimental Evidence

    DEFF Research Database (Denmark)

    Hagenauer, Megan; Crodelle, Jennifer; Piltz, Sofia Helena

    2017-01-01

    conditions, pain sensitivity varies across the 24 h day, with highest sensitivity occurring during the evening in humans. Pain sensitivity is also modulated by sleep behavior, with pain sensitivity increasing in response to the build-up of homeostatic sleep pressure following sleep deprivation or sleep...... of physiologically meaningful stimulation levels. Following this normalization, we find that the estimated impact of the daily rhythm and of sleep deprivation on experimental pain measurements is surprisingly consistent across different pain modalities. We also review evidence documenting the impact of circadian...... rhythms and sleep deprivation on the neural circuitry in the spinal cord underlying pain sensation. The characterization of sleep-dependent and circadian influences on pain sensitivity in this review paper is used to develop and constrain the mathematical models introduced in the two companion articles....

  11. Transcutaneous electrical nerve stimulation: nonparallel antinociceptive effects on chronic clinical pain and acute experimental pain.

    Science.gov (United States)

    Cheing, G L; Hui-Chan, C W

    1999-03-01

    To investigate to what extent a single 60-minute session of transcutaneous electrical nerve stimulation (TENS) would modify chronic clinical pain, acute experimental pain, and the flexion reflex evoked in chronic low back pain patients. Thirty young subjects with chronic low back pain were randomly allocated to two groups, receiving either TENS or placebo stimulation to the lumbosacral region for 60 minutes. The flexion reflex was elicited by an electrical stimulation applied to the subject's right sole and recorded electromyographically from the biceps femoris and the tibialis anterior muscles. Subjective sensation of low back pain and the electrically induced pain were measured by two separate visual analog scales, termed VAS(LBP) and VAS(FR), respectively. Data obtained before, during, and 60 minutes after TENS and placebo stimulations were analyzed using repeated measures ANOVA. The VAS(LBP) score was significantly reduced to 63.1% of the prestimulation value after TENS (pTENS protocol had different degrees of antinociceptive influence on chronic and acute pain in chronic low back pain patients.

  12. Psychophysics, flare, and neurosecretory function in human pain models: capsaicin versus electrically evoked pain.

    Science.gov (United States)

    Geber, Christian; Fondel, Ricarda; Krämer, Heidrun H; Rolke, Roman; Treede, Rolfe-Detlef; Sommer, Claudia; Birklein, Frank

    2007-06-01

    Intradermal capsaicin injection (CAP) and electrical current stimulation (ES) are analyzed in respect to patterns and test-retest reliability of pain as well as sensory and neurosecretory changes. In 10 healthy subjects, 2x CAP (50 microg) and 2x ES (5 to 30 mA) were applied to the volar forearm. The time period between 2 identical stimulations was about 4 months. Pain ratings, areas of mechanical hyperalgesia, and allodynia were assessed. The intensity of sensory changes was quantified by using quantitative sensory testing. Neurogenic flare was assessed by using laser Doppler imaging. Calcitonin gene-related peptide (CGRP) release was quantified by dermal microdialysis in combination with an enzyme immunoassay. Time course and peak pain ratings were different between CAP and ES. Test-retest correlation was high (r > or = 0.73). Both models induced primary heat hyperalgesia and primary plus secondary pin-prick hyperalgesia. Allodynia occurred in about half of the subjects. Maximum flare sizes did not differ between CAP and ES, but flare intensities were higher for ES. Test-retest correlation was higher for flare sizes than for flare intensity. A significant CGRP release could only be measured after CAP. The different time courses of pain stimulation (CAP: rapidly decaying pain versus ES: pain plateau) led to different peripheral neurosecretory effects but induced similar central plasticity and hyperalgesia. The present study gives a detailed overview of psychophysical and neurosecretory characteristics induced by noxious stimulation with capsaicin and electrical current. We describe differences, similarities, and reproducibility of these human pain models. These data might help to interpret past and future results of human pain studies using experimental pain.

  13. [Pain in humans: experimental facts and hypotheses].

    Science.gov (United States)

    Cesaro, P

    1994-09-15

    The description of painful phenomena in humans has to take into account its different components: sensory component (relevant to nociception), affective and emotional components. Nociceptor's (physiology is best understood with electrophysiological and neurochemical methods allowing a clear description of hyperalgesia, with its peripheral and spinal mechanisms. A functional model is partly available to explain allodynia, spontaneous burning pain and lightning pain, the three main consequences following deafferentation. At the thalamo-cortical level, one can describe nociceptive pathways and other pathways or neuronal networks involved in the affective and emotional components of pain.

  14. Healthy volunteers can be phenotyped using cutaneous sensitization pain models.

    Directory of Open Access Journals (Sweden)

    Mads U Werner

    Full Text Available BACKGROUND: Human experimental pain models leading to development of secondary hyperalgesia are used to estimate efficacy of analgesics and antihyperalgesics. The ability to develop an area of secondary hyperalgesia varies substantially between subjects, but little is known about the agreement following repeated measurements. The aim of this study was to determine if the areas of secondary hyperalgesia were consistently robust to be useful for phenotyping subjects, based on their pattern of sensitization by the heat pain models. METHODS: We performed post-hoc analyses of 10 completed healthy volunteer studies (n = 342 [409 repeated measurements]. Three different models were used to induce secondary hyperalgesia to monofilament stimulation: the heat/capsaicin sensitization (H/C, the brief thermal sensitization (BTS, and the burn injury (BI models. Three studies included both the H/C and BTS models. RESULTS: Within-subject compared to between-subject variability was low, and there was substantial strength of agreement between repeated induction-sessions in most studies. The intraclass correlation coefficient (ICC improved little with repeated testing beyond two sessions. There was good agreement in categorizing subjects into 'small area' (1(st quartile [75%] responders: 56-76% of subjects consistently fell into same 'small-area' or 'large-area' category on two consecutive study days. There was moderate to substantial agreement between the areas of secondary hyperalgesia induced on the same day using the H/C (forearm and BTS (thigh models. CONCLUSION: Secondary hyperalgesia induced by experimental heat pain models seem a consistent measure of sensitization in pharmacodynamic and physiological research. The analysis indicates that healthy volunteers can be phenotyped based on their pattern of sensitization by the heat [and heat plus capsaicin] pain models.

  15. The Effect of a Combination of Diclofenac and Methadone Applied as Gel in a Human Experimental Pain Model- A Randomized, Placebo-Controlled Trial

    DEFF Research Database (Denmark)

    Larsen, Isabelle M; Drewes, Asbjørn M; Olesen, Anne E

    2018-01-01

    should be low. We hypothesized that anti-allodynic and anti-hyperalgesic effects of Diclometh could be demonstrated in a human experimental pain model, and that Diclometh would be safe to administer. Thus, the aims were: 1) To compare two doses of Diclometh versus placebo; 2) To assess the safety profile...... of Diclometh. The study was a cross-over, randomized, double-blind, placebo-controlled comparison of two doses of Diclometh gel (0.1% and 0.2%) administered topically in healthy participants. Nerve growth factor (NGF) and capsaicin intradermal injections were used as human pain models. Pressure stimulation...... of anti-allodynic effect of Diclometh 0.2% was found. Additionally, it was demonstrated that Diclometh was safe to use. This article is protected by copyright. All rights reserved....

  16. Placebo effect of an inert gel on experimentally induced leg muscle pain

    Directory of Open Access Journals (Sweden)

    James G Hopker

    2010-11-01

    Full Text Available James G Hopker1, Abigail J Foad2, Christopher J Beedie2, Damian A Coleman2, Geoffrey Leach11Centre for Sports Studies, University of Kent, Chatham, Kent, UK; 2Department of Sports Science, Tourism and Leisure, Canterbury Christ Church University, Canterbury, Kent, UKPurpose: This study examined the therapeutic effects of an inert placebo gel on experimentally induced muscle pain in a sports therapy setting. It aimed to investigate the degree to which conditioned analgesia, coupled with an expectation of intervention, was a factor in subsequent analgesia.Methods: Participants were sixteen male and eight female sports therapy students at a UK University. With institutional ethics board approval and following informed consent procedures, each was exposed to pain stimulus in the lower leg in five conditions, ie, conditioning, prebaseline, experimental (two placebo gel applications, and postbaseline. In conditioning trials, participants identified a level of pain stimulus equivalent to a perceived pain rating of 6/10. An inert placebo gel was then applied to the site with the explicit instruction that it was an analgesic. Participants were re-exposed to the pain stimulus, the level of which, without their knowledge, had been decreased, creating the impression of an analgesic effect resulting from the gel. In experimental conditions, the placebo gel was applied and the level of pain stimulus required to elicit a pain rating of 6/10 recorded.Results: Following application of the placebo gel, the level of pain stimulus required to elicit a pain rating of 6/10 increased by 8.2%. Application of the placebo gel significantly decreased participant’s perceptions of muscle pain (P = 0.001.Conclusion: Subjects’ experience and expectation of pain reduction may be major factors in the therapeutic process. These factors should be considered in the sports therapeutic environment.Keywords: conditioning, expectation, perception, positive belief, sports therapy

  17. A practical guide and perspectives on the use of experimental pain modalities with children and adolescents

    Science.gov (United States)

    Birnie, Kathryn A; Caes, Line; Wilson, Anna C; Williams, Sara E; Chambers, Christine T

    2014-01-01

    SUMMARY Use of experimental pain is vital for addressing research questions that would otherwise be impossible to examine in the real world. Experimental induction of pain in children is highly scrutinized given the potential for harm and lack of direct benefit to a vulnerable population. However, its use has critically advanced our understanding of the mechanisms, assessment and treatment of pain in both healthy and chronically ill children. This article introduces various experimental pain modalities, including the cold pressor task, the water load symptom provocation test, thermal pain, pressure pain and conditioned pain modulation, and discusses their application for use with children and adolescents. It addresses practical implementation and ethical issues, as well as the advantages and disadvantages offered by each task. The incredible potential for future research is discussed given the array of experimental pain modalities now available to pediatric researchers. PMID:24641434

  18. Movement does not promote recovery of motor output following acute experimental muscle pain

    DEFF Research Database (Denmark)

    Schabrun, Siobhan M.; Palsson, Thorvaldur Skuli; Thapa, Tribikram

    2018-01-01

    Objective.:  To examine the effect of motor activity on the magnitude and duration of altered corticomotor output following experimental muscle pain. Design. : Experimental, pre-post test. Setting. : University laboratory. Subjects. : Twenty healthy individuals. Methods.:  Participants were rando....... Understanding corticomotor depression in the postpain period and what factors promote recovery has relevance for clinical pain syndromes where ongoing motor dysfunction, in the absence of pain, may predispose to symptom persistence or recurrence....

  19. Women with dysmenorrhoea are hypersensitive to experimentally induced forearm ischaemia during painful menstruation and during the pain-free follicular phase.

    Science.gov (United States)

    Iacovides, S; Avidon, I; Baker, F C

    2015-07-01

    Monthly primary dysmenorrhoeic pain is associated with increased sensitivity to painful stimuli, particularly in deep tissue. We investigated whether women with dysmenorrhoea, compared with controls, have increased sensitivity to experimentally induced deep-tissue muscle ischaemia in a body area distant from that of referred menstrual pain. The sub-maximal effort tourniquet test was used to induce forearm ischaemia in 11 women with severe dysmenorrhoea and in nine control women both during menstruation and in the follicular phase of the menstrual cycle. Von Frey hair assessments confirmed the presence of experimental ischaemia. Women rated the intensity of menstrual and ischaemic pain on a 100-mm visual analogue scale. Women with dysmenorrhoea [mean (SD): 68 (20) mm] reported significantly greater menstrual pain compared with controls [mean (SD): 2 (6) mm; p = 0.0001] during the menstruation phase. They also rated their forearm ischaemic pain as significantly greater than the controls during the menstruation [dysmenorrhoeics vs. controls mean (SD): 58 (19) mm vs. 31 (21) mm, p menstruation phase and pain-free follicular phase. These findings suggest the presence of long-lasting changes in muscle pain sensitivity in women with dysmenorrhoea. Our findings that dysmenorrhoeic women are hyperalgesic to a clinically relevant, deep-muscle ischaemic pain in areas outside of referred menstrual pain confirm other studies showing long-lasting changes in pain sensitivity outside of the painful period during menstruation. © 2014 European Pain Federation - EFIC®

  20. Multidimensional study of orofacial chronic neuropathic pain: An experimental study in rats.

    Directory of Open Access Journals (Sweden)

    Claudia Daniela Montes-Angeles

    2017-10-01

    Full Text Available Orofacial neuropathic chronic pain (NCP is frequently attributed to lesions caused by orofacial surgeries and dental treatments. There are many experimental models available to study orofacial NCP, however, many are extremely painful for the animal due to the amplitude of the innervated region. A previously proposed mental nerve constriction model, mNC, was used in this project. Forty Wistar rats were randomly divided into two groups: one group included rats with mNC (n=20, and another rats with sham lesions (n=20. Through the use of the fixed ratio program and the progressive program, a decrease of motivation for a sweet substance, caused by the lesion, was evaluated. The possibility of alterations in cognitive learning and adaptation abilities was also assessed using the go/no-go behavioral task. The mNC group showed low induced and spontaneously evoked pain responses, as well as a decrease in the motivation for sucrose, a sign of anhedonia. This decrease does not depend on taste processing. Finally, although no alterations in the learning-memory process were observed, the mNC group did show alterations when adapting to a new rule.

  1. Influence of intramuscular granisetron on experimentally induced muscle pain by acidic saline.

    Science.gov (United States)

    Louca, S; Ernberg, M; Christidis, N

    2013-06-01

    The aim of this study was to investigate whether intramuscular administration of the 5-HT(3) receptor antagonist granisetron reduces experimental muscle pain induced by repeated intramuscular injections of acidic saline into the masseter muscles. Twenty-eight healthy and pain-free volunteers, fourteen women and fourteen men participated in this randomized, double-blind and placebo-controlled study. After a screening examination and registration of the baseline pressure-pain threshold (PPT), the first simultaneous bilateral injections of 0·5 mL acidic saline (9 mg mL(-1) , pH 3·3) into the masseter muscles were performed. Two days later, PPT and pain (VAS) were re-assessed. The masseter muscle was then pre-treated with 0·5 mL granisetron (Kytril(®) 1 mg mL(-1) pH 5·3) on one side and control substance (isotonic saline, 9 mg mL(-1) pH 6) on the contralateral side. Two minutes thereafter a bilateral simultaneous injection of 0·5 mL acidic saline followed. The evoked pain intensity, pain duration, pain area and PPT were assessed. The volunteers returned 1 week later to re-assess VAS and PPT. On the side pre-treated with granisetron, the induced pain had significantly lower intensity and shorter duration (P granisetron on pain duration was significant only in women (P granisetron has a pain-reducing effect on experimentally induced muscle pain by repeated acidic saline injection. © 2013 John Wiley & Sons Ltd.

  2. The influence of experimentally induced pain on shoulder muscle activity

    DEFF Research Database (Denmark)

    Diederichsen, L.P.; Winther, A.; Dyhre-Poulsen, P.

    2009-01-01

    muscles. EMG was recorded before pain, during pain and after pain had subsided and pain intensity was continuously scored on a visual analog scale (VAS). During abduction, experimentally induced pain in the supraspinatus muscle caused a significant decrease in activity of the anterior deltoid, upper......-105A degrees) at a speed of approximately 120A degrees/s, controlled by a metronome. During abduction, electromyographic (EMG) activity was recorded by intramuscular wire electrodes inserted in two deeply located shoulder muscles and by surface-electrodes over six superficially located shoulder...... trapezius and the infraspinatus and an increase in activity of lower trapezius and latissimus dorsi muscles. Following subacromial injection a significantly increased muscle activity was seen in the lower trapezius, the serratus anterior and the latissimus dorsi muscles. In conclusion, this study shows...

  3. The hypoalgesic effect of oxycodone in human experimental pain models in relation to the CYP2D6 oxidation polymorphism

    DEFF Research Database (Denmark)

    Zwisler, Stine T; Enggaard, Thomas P; Noehr-Jensen, Lene

    2009-01-01

    , extensive metabolizers (EM). The objective of the study was to determine if the analgesic effect of oxycodone in human experimental pain depends on its metabolism to oxymorphone. The analgesic effect of oxycodone was evaluated in a randomized, placebo-controlled, double-blinded, crossover experiment...... including 33 (16 EM and 17 PM) healthy volunteers. Pain tests were performed before and 1, 2, 3 and 4 hr after medication and included pain detection and tolerance thresholds to single electrical sural nerve stimulation, pain summation threshold to repetitive electrical sural nerve stimulation and the cold...... pressor test with rating of discomfort and pain-time area under curve (AUC(0-2 min.)). For single sural nerve stimulation, there was a less pronounced increase in thresholds on oxycodone in pain detection (9% vs. 20%, P = 0.02, a difference of 11%, CI: 2%-20%) and pain tolerance thresholds (15% vs. 26%, P...

  4. Pain perception in people with Down syndrome: a synthesis of clinical and experimental research

    Science.gov (United States)

    McGuire, Brian E.; Defrin, Ruth

    2015-01-01

    People with an intellectual disability experience both acute and chronic pain with at least the same frequency as the general population. However, considerably less is known about the pain perception of people with Down syndrome. In this review paper, we evaluated the available clinical and experimental evidence. Some experimental studies of acute pain have indicated that pain threshold was higher than normal but only when using a reaction time method to measure pain sensitivity. However, when reaction time is not part of the calculation of the pain threshold, pain sensitivity in people with Down syndrome is in fact lower than normal (more sensitive to pain). Clinical studies of chronic pain have shown that people with an intellectual disability experience chronic pain and within that population, people with Down syndrome also experience chronic pain, but the precise prevalence of chronic pain in Down syndrome has yet to be established. Taken together, the literature suggests that people with Down syndrome experience pain, both acute and chronic, with at least the same frequency as the rest of the population. Furthermore, the evidence suggests that although acute pain expression appears to be delayed, once pain is registered, there appears to be a magnified pain response. We conclude by proposing an agenda for future research in this area. PMID:26283936

  5. Reorganized trunk muscle activity during multidirectional floor perturbations after experimental low back pain

    DEFF Research Database (Denmark)

    Larsen, Lars Henrik; Hirata, Rogerio Pessoto; Graven-Nielsen, Thomas

    2016-01-01

    Low back pain changes the trunk muscle activity after external perturbations but the relationship between pain intensities and distributions and their effect on the trunk muscle activity remains unclear. The effects of unilateral and bilateral experimental low back pain on trunk muscle activity w...

  6. Multiple sites and actions of gabapentin-induced relief of ongoing experimental neuropathic pain.

    Science.gov (United States)

    Bannister, Kirsty; Qu, Chaoling; Navratilova, Edita; Oyarzo, Janice; Xie, Jennifer Yanhua; King, Tamara; Dickenson, Anthony H; Porreca, Frank

    2017-12-01

    Gabapentin (GBP) is a first-line therapy for neuropathic pain, but its mechanisms and sites of action remain uncertain. We investigated GBP-induced modulation of neuropathic pain following spinal nerve ligation (SNL) in rats. Intravenous or intrathecal GBP reversed evoked mechanical hypersensitivity and produced conditioned place preference (CPP) and dopamine (DA) release in the nucleus accumbens (NAc) selectively in SNL rats. Spinal GBP also significantly inhibited dorsal horn wide-dynamic-range neuronal responses to a range of evoked stimuli in SNL rats. By contrast, GBP microinjected bilaterally into the rostral anterior cingulate cortex (rACC), produced CPP, and elicited NAc DA release selectively in SNL rats but did not reverse tactile allodynia and had marginal effects on wide-dynamic-range neuronal activity. Moreover, blockade of endogenous opioid signaling in the rACC prevented intravenous GBP-induced CPP and NAc DA release but failed to block its inhibition of tactile allodynia. Gabapentin, therefore, can potentially act to produce its pain relieving effects by (a) inhibition of injury-induced spinal neuronal excitability, evoked hypersensitivity, and ongoing pain and (b) selective supraspinal modulation of affective qualities of pain, without alteration of reflexive behaviors. Consistent with previous findings of pain relief from nonopioid analgesics, GBP requires engagement of rACC endogenous opioid circuits and downstream activation of mesolimbic reward circuits reflected in learned pain-motivated behaviors. These findings support the partial separation of sensory and affective dimensions of pain in this experimental model and suggest that modulation of affective-motivational qualities of pain may be the preferential mechanism of GBP's analgesic effects in patients.

  7. Gender role affects experimental pain responses: a systematic review with meta-analysis.

    Science.gov (United States)

    Alabas, O A; Tashani, O A; Tabasam, G; Johnson, M I

    2012-10-01

    Gender role refers to the culturally and socially constructed meanings that describe how women and men should behave in certain situations according to feminine and masculine roles learned throughout life. The aim of this meta-analysis was to evaluate the relationship between gender role and experimental pain responses in healthy human participants. We searched computerized databases for studies published between January 1950 and May 2011 that had measured gender role in healthy human adults and pain response to noxious stimuli. Studies were entered into a meta-analysis if they calculated a correlation coefficient (r) for gender role and experimental pain. Searches yielded 4465 'hits' and 13 studies were eligible for review. Sample sizes were 67-235 participants and the proportion of female participants was 45-67%. Eight types of gender role instrument were used. Meta-analysis of six studies (406 men and 539 women) found a significant positive correlation between masculine and feminine personality traits and pain threshold and tolerance, with a small effect size (r = 0.17, p = 0.01). Meta-analysis of four studies (263 men and 297 women) found a significant negative correlation between gender stereotypes specific to pain and pain threshold and tolerance, with a moderate effect size (r = -0.41, p Gender stereotypes specific to pain scales showed stronger associations with sex differences in pain sensitivity response than masculine and feminine personality trait scales. © 2012 European Federation of International Association for the Study of Pain Chapters.

  8. Involvement of TRPM2 in a wide range of inflammatory and neuropathic pain mouse models

    Directory of Open Access Journals (Sweden)

    Kanako So

    2015-03-01

    Full Text Available Recent evidence suggests a role of transient receptor potential melastatin 2 (TRPM2 in immune and inflammatory responses. We previously reported that TRPM2 deficiency attenuated inflammatory and neuropathic pain in some pain mouse models, including formalin- or carrageenan-induced inflammatory pain, and peripheral nerve injury-induced neuropathic pain models, while it had no effect on the basal mechanical and thermal nociceptive sensitivities. In this study, we further explored the involvement of TRPM2 in various pain models using TRPM2-knockout mice. There were no differences in the chemonociceptive behaviors evoked by intraplantar injection of capsaicin or hydrogen peroxide between wildtype and TRPM2-knockout mice, while acetic acid-induced writhing behavior was significantly attenuated in TRPM2-knockout mice. In the postoperative incisional pain model, no difference in mechanical allodynia was observed between the two genotypes. By contrast, mechanical allodynia in the monosodium iodoacetate-induced osteoarthritis pain model and the experimental autoimmune encephalomyelitis model were significantly attenuated in TRPM2-knockout mice. Furthermore, mechanical allodynia in paclitaxel-induced peripheral neuropathy and streptozotocin-induced painful diabetic neuropathy models were significantly attenuated in TRPM2-knockout mice. Taken together, these results suggest that TRPM2 plays roles in a wide range of pathological pain models based on peripheral and central neuroinflammation, rather than physiological nociceptive pain.

  9. Objective Markers of the analgesic response to morphine in experimental pain research

    DEFF Research Database (Denmark)

    Brokjær, Anne; Olesen, Anne Estrup; Kreilgaard, Mads

    2015-01-01

    INTRODUCTION: In experimental pain research the effect of opioids is normally assessed by verbal subjective response to analgesia. However, as many confounders in pain assessment exist, objective bed-side assessment of the effect is highly warranted. Therefore, we aimed to assess the effect...

  10. Self-reported pain and disability outcomes from an endogenous model of muscular back pain

    Directory of Open Access Journals (Sweden)

    George Steven Z

    2011-02-01

    Full Text Available Abstract Background Our purpose was to develop an induced musculoskeletal pain model of acute low back pain and examine the relationship among pain, disability and fear in this model. Methods Delayed onset muscle soreness was induced in 52 healthy volunteers (23 women, 17 men; average age 22.4 years; average BMI 24.3 using fatiguing trunk extension exercise. Measures of pain intensity, unpleasantness, and location, and disability, were tracked for one week after exercise. Results Pain intensity ranged from 0 to 68 with 57.5% of participants reporting peak pain at 24 hours and 32.5% reporting this at 48 hours. The majority of participants reported pain in the low back with 33% also reporting pain in the legs. The ratio of unpleasantness to intensity indicated that the sensation was considered more unpleasant than intense. Statistical differences were noted in levels of reported disability between participants with and without leg pain. Pain intensity at 24 hours was correlated with pain unpleasantness, pain area and disability. Also, fear of pain was associated with pain intensity and unpleasantness. Disability was predicted by sex, presence of leg pain, and pain intensity; however, the largest amount of variance was explained by pain intensity (27% of a total 40%. The second model, predicting pain intensity only included fear of pain and explained less than 10% of the variance in pain intensity. Conclusions Our results demonstrate a significant association between pain and disability in this model in young adults. However, the model is most applicable to patients with lower levels of pain and disability. Future work should include older adults to improve the external validity of this model.

  11. The genetic influences on oxycodone response characteristics in human experimental pain

    DEFF Research Database (Denmark)

    Olesen, Anne Estrup; Sato, Hiroe; Nielsen, Lecia M

    2015-01-01

    Human experimental pain studies are of value to study basic pain mechanisms under controlled conditions. The aim of this study was to investigate whether genetic variation across selected mu-, kappa- and delta-opioid receptor genes (OPRM1, OPRK1and OPRD1, respectively) influenced analgesic respon......; therefore, variation in opioid receptor genes may partly explain responder characteristics to oxycodone....

  12. Experimental knee joint pain during strength training and muscle strength gain in healthy subjects

    DEFF Research Database (Denmark)

    Sørensen, T J; Langberg, Henning; Hodges, P W

    2012-01-01

    Knee joint pain and reduced quadriceps strength are cardinal symptoms in many knee pathologies. In people with painful knee pathologies, quadriceps exercise reduces pain, improves physical function, and increases muscle strength. A general assumption is that pain compromises muscle function...... and thus may prevent effective rehabilitation. This study evaluated the effects of experimental knee joint pain during quadriceps strength training on muscle strength gain in healthy individuals....

  13. A quantitative review of ethnic group differences in experimental pain response: do biology, psychology, and culture matter?

    Science.gov (United States)

    Rahim-Williams, Bridgett; Riley, Joseph L; Williams, Ameenah K K; Fillingim, Roger B

    2012-04-01

    Pain is a subjectively complex and universal experience. We examine research investigating ethnic group differences in experimental pain response and factors contributing to group differences. We conducted a systematic literature review and analysis of studies using experimental pain stimuli to assess pain sensitivity across multiple ethnic groups. Our search covered the period from 1944 to 2011, and used the PubMed bibliographic database; a reference source containing over 17 million citations. We calculated effect sizes; identified ethnic/racial group categories, pain stimuli, and measures; and examined findings regarding biopsychosociocultural factors contributing to ethnic/racial group differences. We found 472 studies investigating ethnic group differences and pain. Twenty-six of these met our review inclusion criteria of investigating ethnic group differences in experimental pain. The majority of studies included comparisons between African Americans (AA) and non-Hispanic Whites (NHW). There were consistently moderate to large effect sizes for pain tolerance across multiple stimulus modalities; AA demonstrated lower pain tolerance. For pain threshold, findings were generally in the same direction, but effect sizes were small to moderate across ethnic groups. Limited data were available for suprathreshold pain ratings. A subset of studies comparing NHW and other ethnic groups showed a variable range of effect sizes for pain threshold and tolerance. There are potentially important ethnic/racial group differences in experimental pain perception. Elucidating ethnic group differences has translational merit for culturally competent clinical care and for addressing and reducing pain treatment disparities among ethnically/racially diverse groups. Wiley Periodicals, Inc.

  14. The influence of working memory capacity on experimental heat pain.

    Science.gov (United States)

    Nakae, Aya; Endo, Kaori; Adachi, Tomonori; Ikeda, Takashi; Hagihira, Satoshi; Mashimo, Takashi; Osaka, Mariko

    2013-10-01

    Pain processing and attention have a bidirectional interaction that depends upon one's relative ability to use limited-capacity resources. However, correlations between the size of limited-capacity resources and pain have not been evaluated. Working memory capacity, which is a cognitive resource, can be measured using the reading span task (RST). In this study, we hypothesized that an individual's potential working memory capacity and subjective pain intensity are related. To test this hypothesis, we evaluated 31 healthy participants' potential working memory capacity using the RST, and then applied continuous experimental heat stimulation using the listening span test (LST), which is a modified version of the RST. Subjective pain intensities were significantly lower during the challenging parts of the RST. The pain intensity under conditions where memorizing tasks were performed was compared with that under the control condition, and it showed a correlation with potential working memory capacity. These results indicate that working memory capacity reflects the ability to process information, including precise evaluations of changes in pain perception. In this work, we present data suggesting that changes in subjective pain intensity are related, depending upon individual potential working memory capacities. Individual working memory capacity may be a phenotype that reflects sensitivity to changes in pain perception. Copyright © 2013 American Pain Society. Published by Elsevier Inc. All rights reserved.

  15. Neuropathic pain in experimental autoimmune neuritis is associated with altered electrophysiological properties of nociceptive DRG neurons.

    Science.gov (United States)

    Taha, Omneya; Opitz, Thoralf; Mueller, Marcus; Pitsch, Julika; Becker, Albert; Evert, Bernd Oliver; Beck, Heinz; Jeub, Monika

    2017-11-01

    Guillain-Barré syndrome (GBS) is an acute, immune-mediated polyradiculoneuropathy characterized by rapidly progressive paresis and sensory disturbances. Moderate to severe and often intractable neuropathic pain is a common symptom of GBS, but its underlying mechanisms are unknown. Pathology of GBS is classically attributed to demyelination of large, myelinated peripheral fibers. However, there is increasing evidence that neuropathic pain in GBS is associated with impaired function of small, unmyelinated, nociceptive fibers. We therefore examined the functional properties of small DRG neurons, the somata of nociceptive fibers, in a rat model of GBS (experimental autoimmune neuritis=EAN). EAN rats developed behavioral signs of neuropathic pain. This was accompanied by a significant shortening of action potentials due to a more rapid repolarization and an increase in repetitive firing in a subgroup of capsaicin-responsive DRG neurons. Na + current measurements revealed a significant increase of the fast TTX-sensitive current and a reduction of the persistent TTX-sensitive current component. These changes of Na + currents may account for the significant decrease in AP duration leading to an overall increase in excitability and are therefore possibly directly linked to pathological pain behavior. Thus, like in other animal models of neuropathic and inflammatory pain, Na + channels seem to be crucially involved in the pathology of GBS and may constitute promising targets for pain modulating pharmaceuticals. Copyright © 2017 Elsevier Inc. All rights reserved.

  16. Association between Gene Polymorphisms and Pain Sensitivity Assessed in a Multi-Modal Multi-Tissue Human Experimental Model - An Explorative Study

    DEFF Research Database (Denmark)

    Nielsen, Lecia Møller; Olesen, Anne Estrup; Sato, Hiroe

    2016-01-01

    The genetic influence on sensitivity to noxious stimuli (pain sensitivity) remains controversial and needs further investigation. In the present study, the possible influence of polymorphisms in three opioid receptor (OPRM, OPRD and OPRK) genes and the catechol-O-methyltransferase (COMT) gene...... on pain sensitivity in healthy participants was investigated. Catechol-O-methyltransferase has an indirect effect on the mu opioid receptor by changing its activity through an altered endogenous ligand effect. Blood samples for genetic analysis were withdrawn in a multi-modal and multi-tissue experimental......, electrical and thermal visceral stimulations. A cold pressor test was also conducted. DNA was available from 38 of 40 participants. Compared to non-carriers of the COMT rs4680A allele, carriers reported higher bone pressure pain tolerance threshold (i.e. less pain) by up to 23.8% (p

  17. Towards a new model of attentional biases in the development, maintenance, and management of pain.

    Science.gov (United States)

    Todd, Jemma; Sharpe, Louise; Johnson, Ameika; Nicholson Perry, Kathryn; Colagiuri, Ben; Dear, Blake F

    2015-09-01

    Individuals with chronic pain demonstrate attentional biases (ABs) towards pain-related stimuli. However, the clinical importance of these biases is yet to be determined and a sound theoretical model for explaining the role of ABs in the development and maintenance of pain is lacking. Within this article, we (1) systematically review prospective and experimental research exploring ABs and pain outcomes in light of current theoretical models and (2) propose a theoretical framework for understanding AB in pain. Across prospective research, an attentional pattern of vigilance-avoidance was observed. Interventions targeting ABs were less consistent; however, there were promising findings among studies that found attentional training effects, particularly for laboratory research. The proposed Threat Interpretation Model suggests a relationship between threat, interpretation, and stimuli in determining attentional processes, which while tentative generates important testable predictions regarding the role of attention in pain and builds on previous theoretical and empirical work in this area.

  18. Anti-allodynic Effect of Nefopam and Morphine in a Rat Model of Neuropathic Pain

    Directory of Open Access Journals (Sweden)

    Taraneh Moini Zanjani

    2013-05-01

    Full Text Available Please cite this article as: Moini Zanjani T, Saghaei E, Ameli H, Sabetkasaei M. Anti-allodynic Effect of Nefopam and Morphine in a Rat Model of Neuropathic Pain. Novel Biomed 2013;1:16-22.Background: Neuropathic pain is a chronic pain due to a disorder in the peripheral or central nervous system with different pathophysiological mechanisms. Current treatments are not effective. Here we compared the analgesic effect of nefopam, and morphine in chronic constriction injury (CCI model of neuropathic pain.Methods: Male wistar rat (150-200g, n=8 were divided into 3 different groups: 1- Saline-treated CCI group, 2- Saline-treated sham group, and 3- Drug-treated CCI groups. In CCI model of neuropathic pain, the left sciatic nerve was exposed and 4 loose chromic gut ligatures were placed around the nerve proximal to the trifurcation. Ketamine 60mg/kg and xylazine 10 mg/kg were used for anesthesia. Nefopam (10, 20, 30mg/kg, and morphine (1, 3, 5mg/kg were injected 30 minutes before surgery and continued daily to day 14 post-ligation. Von Frey filaments for mechanical allodynia and acetone test for cold allodynia were respectively used as pain behavioral tests. Experiments were performed on day 0 (before surgery and days 1, 3, 5,7,10 and 14 post injury. Behavioral studies were performed in a quiet room between 9:00 to 11:00 AM. All experiments followed the IASP guidelines on ethical standards for investigation of experimental pain in animals.Results: Nefopam (20 and 30mg/kg blocked mechanical and cold allodynia during the experimental period, but the analgesic effects of morphine (5mg/kg lasted for 7 days.Conclusions: It seems that nefopam could effectively reduce pain behavior compared to morphine with reduced adverse effects.

  19. Numbness in clinical and experimental pain--a cross-sectional study exploring the mechanisms of reduced tactile function.

    Science.gov (United States)

    Geber, Christian; Magerl, Walter; Fondel, Ricarda; Fechir, Marcel; Rolke, Roman; Vogt, Thomas; Treede, Rolf-Detlef; Birklein, Frank

    2008-09-30

    Pain patients often report distinct numbness of the painful skin although no structural peripheral or central nerve lesion is obvious. In this cross-sectional study we assessed the reduction of tactile function and studied underlying mechanisms in patients with chronic pain and in healthy participants exposed to phasic and tonic experimental nociceptive stimulation. Mechanical detection (MDT) and pain thresholds (MPT) were assessed in the painful area and the non-painful contralateral side in 10 patients with unilateral musculoskeletal pain. Additionally, 10 healthy participants were exposed to nociceptive stimulation applied to the volar forearms (capsaicin; electrical stimulation, twice each). Areas of tactile hypaesthesia and mechanical hyperalgesia were assessed. MDT and MPT were quantified adjacent to the stimulation site. Tactile hypaesthesia in pain patients and in experimental pain (MDT-z-scores: -0.66+/-0.30 and -0.42+/-0.15, respectively, both p<0.01) was paralleled by mechanical hyperalgesia (MPT-z-scores: +0.51+/-0.27, p<0.05; and +0.48+/-0.10, p<0.001). However, hypaesthesia and hyperalgesia were not correlated. Although 9 patients reported numbness, only 3 of them were able to delineate circumscript areas of tactile hypaesthesia. In experimental pain, the area of tactile hypaesthesia could be mapped in 31/40 experiments (78%). Irrespective of the mode of nociceptive stimulation (phasic vs. tonic) tactile hypaesthesia and hyperalgesia developed with a similar time course and disappeared within approximately 1 day. Hypaesthesia (numbness) often encountered in clinical pain can be reproduced by experimental nociceptive stimulation. The time course of effects suggests a mechanism involving central plasticity.

  20. The role of periodontal ASIC3 in orofacial pain induced by experimental tooth movement in rats.

    Science.gov (United States)

    Gao, Meiya; Long, Hu; Ma, Wenqiang; Liao, Lina; Yang, Xin; Zhou, Yang; Shan, Di; Huang, Renhuan; Jian, Fan; Wang, Yan; Lai, Wenli

    2016-12-01

    This study aimed to clarify the roles of Acid-sensing ion channel 3 (ASIC3) in orofacial pain following experimental tooth movement. Sixty male Sprague-Dawley rats were divided into the experimental group (40g, n = 30) and the sham group (0g, n = 30). Closed coil springs were ligated between maxillary incisor and molars to achieve experimental tooth movement. Rat grimace scale (RGS) scores were assessed at 0, 1, 3, 5, 7, and 14 days after the placement of the springs. ASIC3 immunostaining was performed and the expression levels of ASIC3 were measured through integrated optical density/area in Image-Pro Plus 6.0. Moreover, 18 rats were divided into APETx2 group (n = 6), amiloride group (n = 6), and vehicle group (n = 6), and RGS scores were obtained compared among them to verify the roles of ASIC3 in orofacial pain following tooth movement. ASIC3 expression levels became significantly higher in the experimental group than in sham group on 1, 3, and 5 days and became similar on 7 and 14 days. Pain levels (RGS scores) increased in both groups and were significantly higher in the experimental group on 1, 3, 5, and 7 days and were similar on 14 days. Periodontal ASIC3 expression levels were correlated with orofacial pain levels following experimental tooth movement. Periodontal administrations of ASIC3 antagonists (APETx2 and amiloride) could alleviate pain. This study needs to be better evidenced by RNA interference of ASIC3 in periodontal tissues in rats following experimental tooth movement. Moreover, we hope further studies would concentrate on the pain perception of ASIC3 knockout (ASIC3 -/- ) mice. Our results suggest that periodontal ASIC3 plays an important role in orofacial pain induced by experimental tooth movement. © The Author 2015. Published by Oxford University Press on behalf of the European Orthodontic Society. All rights reserved. For permissions, please email: journals.permissions@oup.com.

  1. The dynamics of the pain system is intact in patients with knee osteoarthritis: An exploratory experimental study.

    Science.gov (United States)

    Jørgensen, Tanja Schjødt; Henriksen, Marius; Rosager, Sara; Klokker, Louise; Ellegaard, Karen; Danneskiold-Samsøe, Bente; Bliddal, Henning; Graven-Nielsen, Thomas

    2017-12-29

    Background and aims Despite the high prevalence of knee osteoarthritis (OA) it remains one of the most frequent knee disorders without a cure. Pain and disability are prominent clinical features of knee OA. Knee OA pain is typically localized but can also be referred to the thigh or lower leg. Widespread hyperalgesia has been found in knee OA patients. In addition, patients with hyperalgesia in the OA knee joint show increased pain summation scores upon repetitive stimulation of the OA knee suggesting the involvement of facilitated central mechanisms in knee OA. The dynamics of the pain system (i.e., the adaptive responses to pain) has been widely studied, but mainly from experiments on healthy subjects, whereas less is known about the dynamics of the pain system in chronic pain patients, where the pain system has been activated for a long time. The aim of this study was to assess the dynamics of the nociceptive system quantitatively in knee osteoarthritis (OA) patients before and after induction of experimental knee pain. Methods Ten knee osteoarthritis (OA) patients participated in this randomized crossover trial. Each subject was tested on two days separated by 1 week. The most affected knee was exposed to experimental pain or control, in a randomized sequence, by injection of hypertonic saline into the infrapatellar fat pad and a control injection of isotonic saline. Pain areas were assessed by drawings on anatomical maps. Pressure pain thresholds (PPT) at the knee, thigh, lower leg, and arm were assessed before, during, and after the experimental pain and control conditions. Likewise, temporal summation of pressure pain on the knee, thigh and lower leg muscles was assessed. Results Experimental knee pain decreased the PPTs at the knee (P system in individuals with knee OA can be affected even after many years of nociceptive input. This study indicates that the adaptability in the pain system is intact in patients with knee OA, which opens for opportunities to

  2. Beyond pain: modeling decision-making deficits in chronic pain

    Science.gov (United States)

    Hess, Leonardo Emanuel; Haimovici, Ariel; Muñoz, Miguel Angel; Montoya, Pedro

    2014-01-01

    Risky decision-making seems to be markedly disrupted in patients with chronic pain, probably due to the high cost that impose pain and negative mood on executive control functions. Patients’ behavioral performance on decision-making tasks such as the Iowa Gambling Task (IGT) is characterized by selecting cards more frequently from disadvantageous than from advantageous decks, and by switching often between competing responses in comparison with healthy controls (HCs). In the present study, we developed a simple heuristic model to simulate individuals’ choice behavior by varying the level of decision randomness and the importance given to gains and losses. The findings revealed that the model was able to differentiate the behavioral performance of patients with chronic pain and HCs at the group, as well as at the individual level. The best fit of the model in patients with chronic pain was yielded when decisions were not based on previous choices and when gains were considered more relevant than losses. By contrast, the best account of the available data in HCs was obtained when decisions were based on previous experiences and losses loomed larger than gains. In conclusion, our model seems to provide useful information to measure each individual participant extensively, and to deal with the data on a participant-by-participant basis. PMID:25136301

  3. Beyond pain: modeling decision-making deficits in chronic pain.

    Science.gov (United States)

    Hess, Leonardo Emanuel; Haimovici, Ariel; Muñoz, Miguel Angel; Montoya, Pedro

    2014-01-01

    Risky decision-making seems to be markedly disrupted in patients with chronic pain, probably due to the high cost that impose pain and negative mood on executive control functions. Patients' behavioral performance on decision-making tasks such as the Iowa Gambling Task (IGT) is characterized by selecting cards more frequently from disadvantageous than from advantageous decks, and by switching often between competing responses in comparison with healthy controls (HCs). In the present study, we developed a simple heuristic model to simulate individuals' choice behavior by varying the level of decision randomness and the importance given to gains and losses. The findings revealed that the model was able to differentiate the behavioral performance of patients with chronic pain and HCs at the group, as well as at the individual level. The best fit of the model in patients with chronic pain was yielded when decisions were not based on previous choices and when gains were considered more relevant than losses. By contrast, the best account of the available data in HCs was obtained when decisions were based on previous experiences and losses loomed larger than gains. In conclusion, our model seems to provide useful information to measure each individual participant extensively, and to deal with the data on a participant-by-participant basis.

  4. Analyzing musculoskeletal neck pain, measured as present pain and periods of pain, with three different regression models: a cohort study

    Directory of Open Access Journals (Sweden)

    Hagberg Mats

    2009-06-01

    Full Text Available Abstract Background In the literature there are discussions on the choice of outcome and the need for more longitudinal studies of musculoskeletal disorders. The general aim of this longitudinal study was to analyze musculoskeletal neck pain, in a group of young adults. Specific aims were to determine whether psychosocial factors, computer use, high work/study demands, and lifestyle are long-term or short-term factors for musculoskeletal neck pain, and whether these factors are important for developing or ongoing musculoskeletal neck pain. Methods Three regression models were used to analyze the different outcomes. Pain at present was analyzed with a marginal logistic model, for number of years with pain a Poisson regression model was used and for developing and ongoing pain a logistic model was used. Presented results are odds ratios and proportion ratios (logistic models and rate ratios (Poisson model. The material consisted of web-based questionnaires answered by 1204 Swedish university students from a prospective cohort recruited in 2002. Results Perceived stress was a risk factor for pain at present (PR = 1.6, for developing pain (PR = 1.7 and for number of years with pain (RR = 1.3. High work/study demands was associated with pain at present (PR = 1.6; and with number of years with pain when the demands negatively affect home life (RR = 1.3. Computer use pattern (number of times/week with a computer session ≥ 4 h, without break was a risk factor for developing pain (PR = 1.7, but also associated with pain at present (PR = 1.4 and number of years with pain (RR = 1.2. Among life style factors smoking (PR = 1.8 was found to be associated to pain at present. The difference between men and women in prevalence of musculoskeletal pain was confirmed in this study. It was smallest for the outcome ongoing pain (PR = 1.4 compared to pain at present (PR = 2.4 and developing pain (PR = 2.5. Conclusion By using different regression models different

  5. Psychological resilience, pain catastrophizing, and positive emotions: perspectives on comprehensive modeling of individual pain adaptation.

    Science.gov (United States)

    Sturgeon, John A; Zautra, Alex J

    2013-03-01

    Pain is a complex construct that contributes to profound physical and psychological dysfunction, particularly in individuals coping with chronic pain. The current paper builds upon previous research, describes a balanced conceptual model that integrates aspects of both psychological vulnerability and resilience to pain, and reviews protective and exacerbating psychosocial factors to the process of adaptation to chronic pain, including pain catastrophizing, pain acceptance, and positive psychological resources predictive of enhanced pain coping. The current paper identifies future directions for research that will further enrich the understanding of pain adaptation and espouses an approach that will enhance the ecological validity of psychological pain coping models, including introduction of advanced statistical and conceptual models that integrate behavioral, cognitive, information processing, motivational and affective theories of pain.

  6. The Effect of Experimental Parkinson on Formalin-Induced Pain in Rat

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    Mohammad Sofiabadi

    2014-04-01

    Full Text Available Background & Objectives : Pain is one of the preceding claims of Parkinson's disease (PD, that its mechanisms have not been fully identified. The purpose of this study was to investigate the chemical pain responses induced by subcutaneous injection of formalin in male parkinsonized rats.   Method : In this experimental study, 40 Wistar male rats were used and PD was established by stereotaxic injection of 6-OHDA toxin into the striatum. Parkinson's disease severity determined by apomorphine-induced rotation test and then the pain response of 4 groups, the control, sham and 2 weak or full Parkinson groups, were evaluated using formalin test. Data were analyzed using ANOVA and Tukey test.   Results : In both acute and chronic phases of the formalin test, the symptoms of pain in different groups were same, but at the interphase stage, pain intensity increased more in Parkinson 's rats, especially in full PD group compared to control (p<0.01.   Conclusion: These results suggest that the nigrostriatal dopaminergic pathway have important modulating role on chronic pain.

  7. PAIN IN A PARKINSON`S DISEASE RODENT ANIMAL MODEL INDUCED WITH 6-HYDROXYDOPAMINE

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    Antioch, I

    2017-06-01

    Full Text Available Pain phenomenon, the unpleasant sensory and emotional event, appears to evidently intrude in Parkinson disease (PD, a disease formally considered to be restricted only to motor deficits. Although over a half of persons with PD suffer from pain manifestations, there are very few reports targeting this issue. Considering the cases when motor symptoms of PD are eclipsed by severe pain disclosure, there is an obvious need of clarifying the intricate implications of pain in PD context. Because there are few studies researching the link between pain and PD in clinical context, but as well in animal models we chose to explore the effects of pain stimuli on a rodent model of PD. Materials and methods: We experimentally induced a PD model in Wistar rats (n=12 by injecting in the substantia nigra, a brain area known to be involved in PD occurrence, one dose of a 6-hydroxidopamine (6-OHDA solution (8µm 6-OHDA base and 4µm physiological saline, utilizing neurosurgery, while their control peers received same dose of saline solution. Two weeks after the intervention the animals were subjected to the hot-plate test, a behavioral task for acquiring pain sensitivity. Results: There was noticed a statistical significant (F(1,10 = 5.67, p=0.038 sensibility of the 6-OHDA rats to thermal pain stimuli (8.2 s ± 0.8 s in 6-OHDA group as compared to their peers (13.8 s ± 1.6 s in controls. Conclusions: The involvement of pain in PD animal models is demonstrated raising questions of how it influences PD evolution. Moreover, this result increases awareness of deficient diagnostic methods of pain in PD and as a consequence, poor treatment of pain manifestations.

  8. Gait changes in patients with knee osteoarthritis are replicated by experimental knee pain

    DEFF Research Database (Denmark)

    Henriksen, Marius; Nielsen, Thomas Graven; Aaboe, Jens

    2010-01-01

    Medial knee osteoarthritis (OA) is characterized by pain and associated with abnormal knee moments during walking. The relationship between knee OA pain and gait changes remains to be clarified, and a better understanding of this link could advance the treatment and prevention of disease...... progression. This study investigated changes in knee moments during walking following experimental knee pain in healthy volunteers, and whether these changes replicated the joint moments observed in medial knee OA patients....

  9. Complex regional pain syndrome (CRPS) or continuous unilateral distal experimental pain stimulation in healthy subjects does not bias visual attention towards one hemifield.

    Science.gov (United States)

    Filippopulos, Filipp M; Grafenstein, Jessica; Straube, Andreas; Eggert, Thomas

    2015-11-01

    In natural life pain automatically draws attention towards the painful body part suggesting that it interacts with different attentional mechanisms such as visual attention. Complex regional pain syndrome (CRPS) patients who typically report on chronic distally located pain of one extremity may suffer from so-called neglect-like symptoms, which have also been linked to attentional mechanisms. The purpose of the study was to further evaluate how continuous pain conditions influence visual attention. Saccade latencies were recorded in two experiments using a common visual attention paradigm whereby orientating saccades to cued or uncued lateral visual targets had to be performed. In the first experiment saccade latencies of healthy subjects were measured under two conditions: one in which continuous experimental pain stimulation was applied to the index finger to imitate a continuous pain situation, and one without pain stimulation. In the second experiment saccade latencies of patients suffering from CRPS were compared to controls. The results showed that neither the continuous experimental pain stimulation during the experiment nor the chronic pain in CRPS led to an unilateral increase of saccade latencies or to a unilateral increase of the cue effect on latency. The results show that unilateral, continuously applied pain stimuli or chronic pain have no or only very limited influence on visual attention. Differently from patients with visual neglect, patients with CRPS did not show strong side asymmetries of saccade latencies or of cue effects on saccade latencies. Thus, neglect-like clinical symptoms of CRPS patients do not involve the allocation of visual attention.

  10. Suprathreshold Heat Pain Response Predicts Activity-Related Pain, but Not Rest-Related Pain, in an Exercise-Induced Injury Model

    Science.gov (United States)

    Coronado, Rogelio A.; Simon, Corey B.; Valencia, Carolina; Parr, Jeffrey J.; Borsa, Paul A.; George, Steven Z.

    2014-01-01

    Exercise-induced injury models are advantageous for studying pain since the onset of pain is controlled and both pre-injury and post-injury factors can be utilized as explanatory variables or predictors. In these studies, rest-related pain is often considered the primary dependent variable or outcome, as opposed to a measure of activity-related pain. Additionally, few studies include pain sensitivity measures as predictors. In this study, we examined the influence of pre-injury and post-injury factors, including pain sensitivity, for induced rest and activity-related pain following exercise induced muscle injury. The overall goal of this investigation was to determine if there were convergent or divergent predictors of rest and activity-related pain. One hundred forty-three participants provided demographic, psychological, and pain sensitivity information and underwent a standard fatigue trial of resistance exercise to induce injury of the dominant shoulder. Pain at rest and during active and resisted shoulder motion were measured at 48- and 96-hours post-injury. Separate hierarchical models were generated for assessing the influence of pre-injury and post-injury factors on 48- and 96-hour rest-related and activity-related pain. Overall, we did not find a universal predictor of pain across all models. However, pre-injury and post-injury suprathreshold heat pain response (SHPR), a pain sensitivity measure, was a consistent predictor of activity-related pain, even after controlling for known psychological factors. These results suggest there is differential prediction of pain. A measure of pain sensitivity such as SHPR appears more influential for activity-related pain, but not rest-related pain, and may reflect different underlying processes involved during pain appraisal. PMID:25265560

  11. Beyond pain: modeling decision-making deficits in chronic pain

    Directory of Open Access Journals (Sweden)

    Leonardo Emanuel Hess

    2014-08-01

    Full Text Available Risky decision-making seems to be markedly disrupted in patients with chronic pain, probably due to the high cost that impose pain and negative mood on executive control functions. Patients’ behavioral performance on decision-making tasks such as the Iowa Gambling Task (IGT is characterized by selecting cards more frequently from disadvantageous than from advantageous decks, and by switching often between competing responses in comparison with healthy controls. In the present study, we developed a simple heuristic model to simulate individuals’ choice behavior by varying the level of decision randomness and the importance given to gains and losses. The findings revealed that the model was able to differentiate the behavioral performance of patients with chronic pain and healthy controls at the group, as well as at the individual level. The best fit of the model in patients with chronic pain was yielded when decisions were not based on previous choices and when gains were considered more relevant than losses. By contrast, the best account of the available data in healthy controls was obtained when decisions were based on previous experiences and losses loomed larger than gains. In conclusion, our model seems to provide useful information to measure each individual participant extensively, and to deal with the data on a participant-by-participant basis.

  12. Characterisation of tramadol, morphine and tapentadol in an acute pain model in Beagle dogs.

    Science.gov (United States)

    Kögel, Babette; Terlinden, Rolf; Schneider, Johannes

    2014-05-01

    To evaluate the analgesic potential of the centrally acting analgesics tramadol, morphine and the novel analgesic tapentadol in a pre-clinical research model of acute nociceptive pain, the tail-flick model in dogs. Prospective part-randomized pre-clinical research trial. Fifteen male Beagle dogs (HsdCpb:DOBE), aged 12-15 months. On different occasions separated by at least 1 week, dogs received intravenous (IV) administrations of tramadol (6.81, 10.0 mg kg(-1) ), tapentadol (2.15, 4.64, 6.81 mg kg(-1) ) or morphine (0.464, 0.681, 1.0 mg kg(-1) ) with subsequent measurement of tail withdrawal latencies from a thermal stimulus (for each treatment n = 5). Blood samples were collected immediately after the pharmacodynamic measurements of tramadol to determine pharmacokinetics and the active metabolite O-demethyltramadol (M1). Tapentadol and morphine induced dose-dependent antinociception with ED50-values of 4.3 mg kg(-1) and 0.71 mg kg(-1) , respectively. In contrast, tramadol did not induce antinociception at any dose tested. Measurements of the serum levels of tramadol and the M1 metabolite revealed only marginal amounts of the M1 metabolite, which explains the absence of the antinociceptive effect of tramadol in this experimental pain model in dogs. Different breeds of dogs might not or only poorly respond to treatment with tramadol due to low metabolism of the drug. Tapentadol and morphine which act directly on μ-opioid receptors without the need for metabolic activation are demonstrated to induce potent antinociception in the experimental model used and should also provide a reliable pain management in the clinical situation. The non-opioid mechanisms of tramadol do not provide antinociception in this experimental setting. This contrasts to many clinical situations described in the literature, where tramadol appears to provide useful analgesia in dogs for post-operative pain relief and in more chronically pain states. © 2014 Association of Veterinary

  13. Brain Network Response to Acupuncture Stimuli in Experimental Acute Low Back Pain: An fMRI Study

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    Yu Shi

    2015-01-01

    Full Text Available Most neuroimaging studies have demonstrated that acupuncture can significantly modulate brain activation patterns in healthy subjects, while only a few studies have examined clinical pain. In the current study, we combined an experimental acute low back pain (ALBP model and functional magnetic resonance imaging (fMRI to explore the neural mechanisms of acupuncture analgesia. All ALBP subjects first underwent two resting state fMRI scans at baseline and during a painful episode and then underwent two additional fMRI scans, once during acupuncture stimulation (ACUP and once during tactile stimulation (SHAM pseudorandomly, at the BL40 acupoint. Our results showed that, compared with the baseline, the pain state had higher regional homogeneity (ReHo values in the pain matrix, limbic system, and default mode network (DMN and lower ReHo values in frontal gyrus and temporal gyrus; compared with the OFF status, ACUP yielded broad deactivation in subjects, including nearly all of the limbic system, pain status, and DMN, and also evoked numerous activations in the attentional and somatosensory systems; compared with SHAM, we found that ACUP induced more deactivations and fewer activations in the subjects. Multiple brain networks play crucial roles in acupuncture analgesia, suggesting that ACUP exceeds a somatosensory-guided mind-body therapy for ALBP.

  14. Sex differences in pain: a brief review of clinical and experimental findings.

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    Bartley, E J; Fillingim, R B

    2013-07-01

    Recent years have witnessed substantially increased research regarding sex differences in pain. The expansive body of literature in this area clearly suggests that men and women differ in their responses to pain, with increased pain sensitivity and risk for clinical pain commonly being observed among women. Also, differences in responsivity to pharmacological and non-pharmacological pain interventions have been observed; however, these effects are not always consistent and appear dependent on treatment type and characteristics of both the pain and the provider. Although the specific aetiological basis underlying these sex differences is unknown, it seems inevitable that multiple biological and psychosocial processes are contributing factors. For instance, emerging evidence suggests that genotype and endogenous opioid functioning play a causal role in these disparities, and considerable literature implicates sex hormones as factors influencing pain sensitivity. However, the specific modulatory effect of sex hormones on pain among men and women requires further exploration. Psychosocial processes such as pain coping and early-life exposure to stress may also explain sex differences in pain, in addition to stereotypical gender roles that may contribute to differences in pain expression. Therefore, this review will provide a brief overview of the extant literature examining sex-related differences in clinical and experimental pain, and highlights several biopsychosocial mechanisms implicated in these male-female differences. The future directions of this field of research are discussed with an emphasis aimed towards further elucidation of mechanisms which may inform future efforts to develop sex-specific treatments.

  15. Effects of unilateral and bilateral experimental low-back pain on trunk muscle activity during stair walking in healthy and recurrent low-back pain patients

    DEFF Research Database (Denmark)

    Larsen, Lars Henrik; Hirata, Rogerio Pessoto; Graven-Nielsen, Thomas

    Aim To explore the trunk muscle activity in healthy and recurrent low back pain (R-LBP) patients with no present pain during stair ascent and descent before and after unilateral and bilateral experimental low back pain (LBP). Methods Twenty-five healthy controls and 25 pain-free R-LBP patients wi...... in the physical examination, but it remains unknown if the observed changes are appropriate strategies in relation to the pain condition. Acknowledgement The study was supported by CNAP, Aalborg University and UCN Department of physiotherapy, Denmark....

  16. The effect of electroacupuncture and tramadol on experimental tourniquet pain.

    Science.gov (United States)

    Musial, Frauke; Choi, Kyung-Eun; Gabriel, Tim; Lüdtke, Rainer; Rampp, Thomas; Michalsen, Andreas; Dobos, Gustav

    2012-03-01

    The hypoalgesic effect of electroacupuncture (EA) was directly compared with the analgesic effect of pharmacological interventions using the submaximum effort tourniquet technique (SETT). 125 healthy subjects (mean age 24.44±4.46 years; 62.4% female, 37.6% male) performed SETT at baseline and under one of five experimental conditions (n=25 per group): EA (2 Hz with burst pulses in alternating one-phase-square wave pulses; burst length 180 μs, burst frequency 80 Hz, stimulation time/pulse width 3 s), tramadol (50 mg), ibuprofen (400 mg), placebo pill or non-treatment control. EA was performed at LI4 and LI10 contralaterally with stimulation beginning 20 min before SETT and lasting throughout SETT. The pharmacological interventions were given in a double-blind design 1 h before the SETT assessment. Subjects showed a hypoalgesic effect of the opiate and of the EA for subjective pain rating (EA p=0.0051; tramadol p=0.0299), and pain tolerance index (time/rating) (EA p=0.043; tramadol p=0.047) analysed using analysis of covariance. More subjects reached the strict time limit of 30 min (analysed by logistic regression and adjusted OR as a post-hoc analysis) under EA compared with most other experimental conditions. Only EA and tramadol were not significantly different (95% Wald confidence limits: non-treatment control vs EA 0.011 to 0.542; placebo pill vs EA 0.009 to 0.438; ibuprofen vs EA 0.021 to 0.766; tramadol vs EA 0.065 to 1.436). In a laboratory setting, an EA procedure was as effective as a single dose of an orally administered opiate in reducing experimentally induced ischaemic pain.

  17. The effects of experimental pain and induced optimism on working memory task performance.

    Science.gov (United States)

    Boselie, Jantine J L M; Vancleef, Linda M G; Peters, Madelon L

    2016-07-01

    Pain can interrupt and deteriorate executive task performance. We have previously shown that experimentally induced optimism can diminish the deteriorating effect of cold pressor pain on a subsequent working memory task (i.e., operation span task). In two successive experiments we sought further evidence for the protective role of optimism on pain-induced working memory impairments. We used another working memory task (i.e., 2-back task) that was performed either after or during pain induction. Study 1 employed a 2 (optimism vs. no-optimism)×2 (pain vs. no-pain)×2 (pre-score vs. post-score) mixed factorial design. In half of the participants optimism was induced by the Best Possible Self (BPS) manipulation, which required them to write and visualize about a life in the future where everything turned out for the best. In the control condition, participants wrote and visualized a typical day in their life (TD). Next, participants completed either the cold pressor task (CPT) or a warm water control task (WWCT). Before (baseline) and after the CPT or WWCT participants working memory performance was measured with the 2-back task. The 2-back task measures the ability to monitor and update working memory representation by asking participants to indicate whether the current stimulus corresponds to the stimulus that was presented 2 stimuli ago. Study 2 had a 2 (optimism vs. no-optimism)×2 (pain vs. no-pain) mixed factorial design. After receiving the BPS or control manipulation, participants completed the 2-back task twice: once with painful heat stimulation, and once without any stimulation (counter-balanced order). Continuous heat stimulation was used with temperatures oscillating around 1°C above and 1°C below the individual pain threshold. In study 1, the results did not show an effect of cold pressor pain on subsequent 2-back task performance. Results of study 2 indicated that heat pain impaired concurrent 2-back task performance. However, no evidence was found

  18. Population pharmacokinetic-pharmacodynamic modeling of ketamine-induced pain relief of chronic pain.

    Science.gov (United States)

    Dahan, Albert; Olofsen, Erik; Sigtermans, Marnix; Noppers, Ingeborg; Niesters, Marieke; Aarts, Leon; Bauer, Martin; Sarton, Elise

    2011-03-01

    Pharmacological treatment of chronic (neuropathic) pain is often disappointing. In order to enhance our insight in the complex interaction between analgesic drug and chronic pain relief, we performed a pharmacokinetic-pharmacodynamic (PK-PD) modeling study on the effect of S(+)-ketamine on pain scores in Complex Regional Pain Syndrome type 1 (CRPS-1) patients. Sixty CRPS-1 patients were randomly allocated to received a 100-h infusion of S(+)-ketamine or placebo. The drug infusion rate was slowly increased from 5 mg/h (per 70 kg) to 20 mg/h based upon the effect/side effect profile. Pain scores and drug blood samples were obtained during the treatment phase and pain scores were further obtained weekly for another 11 weeks. A population PK-PD model was developed to analyze the S(+)-ketamine-pain data. Plasma concentrations of S(+)-ketamine and its metabolite decreased rapidly upon the termination of S(+)-ketamine infusion. The chance for an analgesic effect from ketamine and placebo treatment was 67±10% and 23±9% (population value±SE), respectively. The pain data were well described by the PK-PD model with parameters C(50)=10.5±4.8 ng/ml (95% ci 4.37-21.2 ng/ml) and t½ for onset/offset=10.9±4.0 days (5.3-20.5 days). Long-term S(+)-ketamine treatment is effective in causing pain relief in CRPS-1 patients with analgesia outlasting the treatment period by 50 days. These data suggest that ketamine initiated a cascade of events, including desensitization of excitatory receptor systems in the central nervous system, which persisted but slowly abated when ketamine molecules were no longer present. Copyright © 2010 European Federation of International Association for the Study of Pain Chapters. Published by Elsevier Ltd. All rights reserved.

  19. The Effect of Parental Modeling on Child Pain Responses: The Role of Parent and Child Sex.

    Science.gov (United States)

    Boerner, Katelynn E; Chambers, Christine T; McGrath, Patrick J; LoLordo, Vincent; Uher, Rudolf

    2017-06-01

    Social modeling is a process by which pain behaviors are learned, and research has found parents act as models for their children's behavior. Despite social learning theory predicting that same-sex models have greater effect, no experimental investigation to date has examined the role of sex of the model or observer in social learning of pediatric pain. The present study recruited 168 parent-child dyads (equal father-son, father-daughter, mother-son, and mother-daughter dyads) in which children were generally healthy and 6 to 8 years old. Unbeknownst to their child, parents were randomly assigned to exaggerate their expression of pain, minimize their expression of pain, or act naturally during the cold pressor task (CPT). Parents completed the CPT while their child observed, then children completed the CPT themselves. Children whose parents were in the exaggerate condition reported higher anxiety than children of parents in the minimize condition. Additionally, girls in the exaggerate condition rated their overall pain intensity during the CPT significantly higher than boys in the same condition. No child sex differences were observed in pain intensity for the control or minimize conditions. Parent expressions of pain affects children's anxiety, and sex-specific effects of parental exaggerated pain expression on children's own subsequent pain experience are present. This article describes how parental expressions of pain influence children's pain and anxiety, specifically examining the relevance of parent and child sex in this process. These findings have implications for children of parents with chronic pain, or situations in which parents experience pain in the presence of their child (eg, vaccinations). Copyright © 2017 American Pain Society. Published by Elsevier Inc. All rights reserved.

  20. Functional resonance magnetic imaging (fMRI) in adolescents with idiopathic musculoskeletal pain: a paradigm of experimental pain.

    Science.gov (United States)

    Molina, Juliana; Amaro, Edson; da Rocha, Liana Guerra Sanches; Jorge, Liliana; Santos, Flavia Heloisa; Len, Claudio A

    2017-11-14

    Studies on functional magnetic resonance imaging (fMRI) have shown that adults with musculoskeletal pain syndromes tolerate smaller amount of pressure (pain) as well as differences in brain activation patterns in areas related to pain.The objective of this study was to evaluate, through fMRI, the brain activation in adolescents with idiopathic musculoskeletal pain (IMP) while performing an experimental paradigm of pain. The study included 10 consecutive adolescents with idiopathic musculoskeletal pain (average age 16.3±1.0) and 10 healthy adolescents age-matched. fMRI exams were performed in a 3 T scanner (Magnetom Trio, Siemens) using an event-related design paradigm. Pressure stimuli were performed in the nondominant hand thumb, divided into two stages, fixed pain and variable pain. The two local Research Ethics Committees (Ethics Committee from Universidade Federal de São Paulo- Brazil, process number 0688/11, on July 1st, 2011 and Ethics Committee from Hospital Israelita Albert Einsten - Brazil, process number 1673, on October 19th, 2011) approved the study. The idiopathic musculoskeletal pain (IMP) group showed a reduced threshold for pain (3.7 kg/cm 2 versus 4.45 kg/cm 2 , p = 0.005). Control group presented increased bain activation when compared to IMP group in the following areas: thalamus (p = 0.00001), precentral gyrus (p = 0.0004) and middle frontal gyrus (p = 0.03). In intragroup analysis, IMP group showed greater brain activation during the unpredictable stimuli of the variable pain stage, especially in the lingual gyrus (p = 0.0001), frontal lobe (p = 0.0001), temporal gyrus (p = 0.0001) and precentral gyrus (p = 0.03), when compared to predictable stimulus of fixed pain. The same intragroup analysis with the control group showed greater activation during the unpredictable stimuli in regions of the precentral gyrus (p = 0.0001), subcallosal area (p = 0.0001), right and left occipital fusiform gyrus (p

  1. Pain modulatory phenotypes differentiate subgroups with different clinical and experimental pain sensitivity

    DEFF Research Database (Denmark)

    Vaegter, Henrik B.; Graven-Nielsen, Thomas

    2016-01-01

    between subgroups. Cuff algometry was performed on lower legs in 400 chronic pain patients to assess pressure pain threshold (cPPT), pressure pain tolerance (cPTT), temporal summation of pain (TSP: increase in pain scores to ten repeated stimulations), and conditioned pain modulation (CPM: increase in c......PPT during cuff pain conditioning on the contralateral leg). Heat detection (HDT) and heat pain thresholds (HPT) at clinical painful and non-painful body areas were assessed. Based on TSP and CPM four distinct groups were formed: Group 1 (n=85) had impaired CPM and facilitated TSP. Group 2 (n=148) had...... impaired CPM and normal TSP. Group 3 (n=45) had normal CPM and facilitated TSP. Group 4 (n=122) had normal CPM and normal TSP. Group 1 showed more pain regions compared with the other three groups (PCPM and facilitated TSP plays an important role in widespread pain. Group 1...

  2. Increased circulating rather than spinal cytokines accompany chronic pain behaviors in experimental bone cancer and arthritis

    Directory of Open Access Journals (Sweden)

    Line Pourtau

    2014-12-01

    Full Text Available Aim: Peripheral cytokines contribute to arthritis and bone cancer pain through sensory nerve actions. However, increased spinal cytokine and glial filament expression, coined neuroinflammation, has also been proposed to play a part in chronic pain. Therefore, spinal cord, dorsal root ganglia and circulating cytokines were compared in murine arthritis and bone cancer models in relationship to behavioral signs of pain. Methods: Exploratory behaviors were studied after intra-articular complete Freund's adjuvant or bone intramedullary sarcoma cell injection. Nervous tissue and blood cytokine expression were determined by real-time polymerase chain reaction (PCR and multiplex immunoassays, respectively. Results: PCR analysis did not reveal any hallmark of spinal neuroinflammation in spontaneously-behaving mice with cartilage or bone lesions. However, imposed paw stimulation during joint inflammation increased spinal interleukin-1β (IL-1β expression. Spontaneous paw guarding during rearing was displayed by animals with joint inflammation and bone destruction and was accompanied by increased circulating IL-6 and monocyte chemoattractant protein-1, respectively. In addition, dorsal root ganglia were found to constitutively express receptors for this chemotactic cytokine. Conclusion: Our findings indicate that spinal neuroinflammation is not a necessary condition for chronic pain and suggest that circulating cytokine action in dorsal root ganglia may contribute to experimental joint inflammation and bone cancer pain.

  3. Kinesthetic illusions attenuate experimental muscle pain, as do muscle and cutaneous stimulation.

    Science.gov (United States)

    Gay, André; Aimonetti, Jean-Marc; Roll, Jean-Pierre; Ribot-Ciscar, Edith

    2015-07-30

    In the present study, muscle pain was induced experimentally in healthy subjects by administrating hypertonic saline injections into the tibialis anterior (TA) muscle. We first aimed at comparing the analgesic effects of mechanical vibration applied to either cutaneous or muscle receptors of the TA or to both types simultaneously. Secondly, pain alleviation was compared in subjects in whom muscle tendon vibration evoked kinesthetic illusions of the ankle joint. Muscle tendon vibration, which primarily activated muscle receptors, reduced pain intensity by 30% (p<0.01). In addition, tangential skin vibration reduced pain intensity by 33% (p<0.01), primarily by activating cutaneous receptors. Concurrently stimulating both sensory channels induced stronger analgesic effects (-51%, p<0.01), as shown by the lower levels of electrodermal activity. The strongest analgesic effects of the vibration-induced muscle inputs occurred when illusory movements were perceived (-38%, p=0.01). The results suggest that both cutaneous and muscle sensory feedback reduce muscle pain, most likely via segmental and supraspinal processes. Further clinical trials are needed to investigate these new methods of muscle pain relief. Copyright © 2015 Elsevier B.V. All rights reserved.

  4. Biopsychosocial model of chronic recurrent pain

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    Zlatka Rakovec-Felser

    2009-07-01

    Full Text Available Pain is not merely a symptom of disease but a complex independent phenomenon where psychological factors are always present (Sternberg, 1973. Especially by chronic, recurrent pain it's more constructive to think of chronic pain as a syndrome that evolves over time, involving a complex interaction of physiological/organic, psychological, and behavioural processes. Study of chronic recurrent functional pain covers tension form of headache. 50 suffering persons were accidentally chosen among those who had been seeking medical help over more than year ago. We tested their pain intensity and duration, extent of subjective experience of accommodation efforts, temperament characteristics, coping strategies, personal traits, the role of pain in intra- and interpersonal communication. At the end we compared this group with control group (without any manifest physical disorders and with analyse of variance (MANOVA. The typical person who suffers and expects medical help is mostly a woman, married, has elementary or secondary education, is about 40. Pain, seems to appear in the phase of stress-induced psychophysical fatigue, by persons with lower constitutional resistance to different influences, greater irritability and number of physiologic correlates of emotional tensions. Because of their ineffective style of coping, it seems they quickly exhausted their adaptation potential too. Through their higher level of social–field dependence, reactions of other persons (doctor, spouse could be important factors of reinforcement and social learning processes. In managing of chronic pain, especially such as tension headache is, it's very important to involve bio-psychosocial model of pain and integrative model of treatment. Intra- and inter-subjective psychological functions of pain must be recognised as soon as possible.

  5. The necessity of animal models in pain research.

    Science.gov (United States)

    Mogil, Jeffrey S; Davis, Karen D; Derbyshire, Stuart W

    2010-10-01

    There exists currently a fair degree of introspection in the pain research community about the value of animal research. This review represents a defense of animal research in pain. We discuss the inherent advantage of animal models over human research as well as the crucial complementary roles animal studies play vis-à-vis human imaging and genetic studies. Finally, we discuss recent developments in animal models of pain that should improve the relevance and translatability of findings using laboratory animals. We believe that pain research using animal models is a continuing necessity-to understand fundamental mechanisms, identify new analgesic targets, and inform, guide and follow up human studies-if novel analgesics are to be developed for the treatment of chronic pain. Copyright © 2010 International Association for the Study of Pain. Published by Elsevier B.V. All rights reserved.

  6. Operant conditioning of facial displays of pain.

    Science.gov (United States)

    Kunz, Miriam; Rainville, Pierre; Lautenbacher, Stefan

    2011-06-01

    The operant model of chronic pain posits that nonverbal pain behavior, such as facial expressions, is sensitive to reinforcement, but experimental evidence supporting this assumption is sparse. The aim of the present study was to investigate in a healthy population a) whether facial pain behavior can indeed be operantly conditioned using a discriminative reinforcement schedule to increase and decrease facial pain behavior and b) to what extent these changes affect pain experience indexed by self-ratings. In the experimental group (n = 29), the participants were reinforced every time that they showed pain-indicative facial behavior (up-conditioning) or a neutral expression (down-conditioning) in response to painful heat stimulation. Once facial pain behavior was successfully up- or down-conditioned, respectively (which occurred in 72% of participants), facial pain displays and self-report ratings were assessed. In addition, a control group (n = 11) was used that was yoked to the reinforcement plans of the experimental group. During the conditioning phases, reinforcement led to significant changes in facial pain behavior in the majority of the experimental group (p .136). Fine-grained analyses of facial muscle movements revealed a similar picture. Furthermore, the decline in facial pain displays (as observed during down-conditioning) strongly predicted changes in pain ratings (R(2) = 0.329). These results suggest that a) facial pain displays are sensitive to reinforcement and b) that changes in facial pain displays can affect self-report ratings.

  7. Modeling subjective well-being in individuals with chronic pain and a physical disability: the role of pain control and pain catastrophizing.

    Science.gov (United States)

    Furrer, Angela; Michel, Gisela; Terrill, Alexandra L; Jensen, Mark P; Müller, Rachel

    2017-10-23

    To investigate the associations between subjective well-being and pain intensity, pain interference, and depression in individuals with physical disabilities. We hypothesized that (1) pain control and (2) pain catastrophizing mediate the effects of subjective well-being on pain intensity, pain interference, and depression. Analyses of cross-sectional data from 96 individuals diagnosed with spinal cord injury, multiple sclerosis, neuromuscular disease, or post-polio syndrome, with average pain intensity of ≥4 (0-10) on at least half the days in the past month. Two models tested study hypotheses using structural equation. Both models showed acceptable model fit. Pain catastrophizing significantly mediated the effect of subjective well-being on pain intensity and pain interference, but not on depression. Pain control did not significantly mediate the effect of subjective well-being on pain intensity, pain interference, or depression. Path coefficients showed significant direct effects of subjective well-being on pain control (β = 0.39), pain catastrophizing (β = -0.61), pain interference (β = -0.48; -0.42), and depression (β = -0.75; -0.78). This study supports the potential of enhancing subjective well-being and lowering pain catastrophizing for reducing pain intensity, pain interference, and depressive symptoms in individuals with chronic pain and a physical disability. The findings indicate that true experiments to test for causal associations are warranted. Implications for rehabilitation The majority of individuals with physical disabilities report having persistent moderate-to-severe pain that may negatively limit daily activities and quality of life. The present cross-sectional study indicates that individuals who reported greater subjective well-being showed significantly lower pain intensity via the mediating effect of lower pain catastrophizing. Since sample size and respective power are low, these findings should be taken as first

  8. Sex differences in experimental measures of pain sensitivity and endogenous pain inhibition

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    Bulls HW

    2015-06-01

    Full Text Available Hailey W Bulls,1 Emily L Freeman,1 Austen JB Anderson,2 Meredith T Robbins,3 Timothy J Ness,3 Burel R Goodin1,3 1Department of Psychology, University of Alabama at Birmingham, Birmingham, AL, USA; 2Department of Biology, Samford University, Birmingham, AL, USA; 3Department of Anesthesiology, University of Alabama at Birmingham, Birmingham, AL, USA Abstract: It has been suggested that increased pain sensitivity and disruption of endogenous pain inhibitory processes may account, at least in part, for the greater prevalence and severity of chronic pain in women compared to men. However, previous studies addressing this topic have produced mixed findings. This study examined sex differences in pain sensitivity and inhibition using quantitative sensory testing (QST, while also considering the influence of other important factors such as depressive symptoms and sleep quality. Healthy men (n=24 and women (n=24 each completed a QST battery. This battery included an ischemic pain task (IPT that used a submaximal effort tourniquet procedure as well as a conditioned pain modulation (CPM procedure for the assessment of endogenous pain inhibition. Prior to QST, participants completed the Center for Epidemiologic Studies Depression Scale and the Pittsburgh Sleep Quality Index. Analyses revealed significant sex differences for the ischemic pain task and the conditioned pain modulation procedure, such that women tolerated the ischemic pain for a shorter amount of time and demonstrated less pain inhibition compared with men. This remained true even when accounting for sex differences in depressive symptoms and sleep quality. The results of this study suggest that women may be more pain sensitive and possess less-efficient endogenous pain inhibitory capacity compared with men. Whether interventions that decrease pain sensitivity and enhance pain inhibition in women ultimately improve their clinical pain outcomes is an area of research that deserves additional

  9. Prices need no preferences: social trends determine decisions in experimental markets for pain relief.

    Science.gov (United States)

    Vlaev, Ivo; Seymour, Ben; Chater, Nick; Winston, Joel S; Yoshida, Wako; Wright, Nicholas; Symmonds, Mkael; Dolan, Ray

    2014-01-01

    A standard view in health economics is that, although there is no market that determines the "prices" for health states, people can nonetheless associate health states with monetary values (or other scales, such as quality adjusted life year [QALYs] and disability adjusted life year [DALYs]). Such valuations can be used to shape health policy, and a major research challenge is to elicit such values from people; creating experimental "markets" for health states is a theoretically attractive way to address this. We explore the possibility that this framework may be fundamentally flawed-because there may not be any stable values to be revealed. Instead, perhaps people construct ad hoc values, influenced by contextual factors, such as the observed decisions of others. The participants bid to buy relief from equally painful electrical shocks to the leg and arm in an experimental health market based on an interactive second-price auction. Thirty subjects were randomly assigned to two experimental conditions where the bids by "others" were manipulated to follow increasing or decreasing price trends for one, but not the other, pain. After the auction, a preference test asked the participants to choose which pain they prefer to experience for a longer duration. Players remained indifferent between the two pain-types throughout the auction. However, their bids were differentially attracted toward what others bid for each pain, with overbidding during decreasing prices and underbidding during increasing prices. Health preferences are dissociated from market prices, which are strongly referenced to others' choices. This suggests that the price of health care in a free-market has the capacity to become critically detached from people's underlying preferences. 2014 APA, all rights reserved

  10. Time discounting and pain anticipation. Experimental evidence

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    Brañas Garza, Pablo

    2012-03-01

    Full Text Available This paper deals with pain anticipation experienced before medical procedures. our experimental results show that individuals with lower time discount factors are more prone to suffer pain in advance. We provide a framework to rationalize the connection between pain anticipation and impatience. in this set up, more impatient subjects, who only value very near events, mainly take into account the present negative effects of medical procedures (the costs, whereas more patient individuals have a net positive valuation of medical events, given that they are able to value both the cost incurred now and all the benefits to be accrued in the future.

    Este artículo trata de la anticipación del dolor experimentada antes de los procedimientos médicos. nuestros resultados experimentales muestran que los individuos con factor de descuento temporal más bajo son más proclives a sufrir dolor por adelantado. el artículo proporciona un marco en el que racionalizar la relación existente entre impaciencia y anticipación del dolor. en este marco, los sujetos más impacientes, que evalúan sólo los eventos muy próximos en el tiempo, focalizan su atención principalmente en los efectos negativos de los procedimientos médicos (sólo los costes, mientras que los individuos más pacientes tienen una valoración neta positiva de los actos médicos puesto que valoran tanto el coste en el que se incurre en el presente como los beneficios que se obtendrán en el futuro.

  11. Using an experimental model for the study of therapeutic touch.

    Science.gov (United States)

    dos Santos, Daniella Soares; Marta, Ilda Estéfani Ribeiro; Cárnio, Evelin Capellari; de Quadros, Andreza Urba; Cunha, Thiago Mattar; de Carvalho, Emilia Campos

    2013-02-01

    to verify whether the Paw Edema Model can be used in investigations about the effects of Therapeutic Touch on inflammation by measuring the variables pain, edema and neutrophil migration. this is a pilot and experimental study, involving ten male mice of the same genetic strain and divided into experimental and control group, submitted to the chemical induction of local inflammation in the right back paw. The experimental group received a daily administration of Therapeutic Touch for 15 minutes during three days. the data showed statistically significant differences in the nociceptive threshold and in the paw circumference of the animals from the experimental group on the second day of the experiment. the experiment model involving animals can contribute to study the effects of Therapeutic Touch on inflammation, and adjustments are suggested in the treatment duration, number of sessions and experiment duration.

  12. Effect of music therapy on pain behaviors in rats with bone cancer pain.

    Science.gov (United States)

    Gao, Ji; Chen, Shaoqin; Lin, Suyong; Han, Hongjing

    2016-01-01

    To investigate the effects of music therapy on the pain behaviors and survival of rats with bone cancer pain and analyze the mediating mechanism of mitogen activated protein kinase (MAPK) signal transduction pathway. Male Wistar rats aged 5-8 weeks and weighing 160-200 g were collected. The rat models of colorectal cancer bone cancer pain was successfully established. Animals were divided into experimental and control group, each with 10 rats. The animals in the observation group were given Mozart K448 sonata, sound intensity of 60 db, played the sonata once every 1 hr in the daytime, stopped playing during the night, and this cycle was kept for 2 weeks. On the other hand, rats in the control group were kept under the same environment without music. Animals in the experimental group consumed more feed and gained significant weight in comparison to the control group. The tumor volume of the experimental group was significantly smaller than that of the control group (pMusic therapy may improve the pain behaviors in rats with bone cancer pain, which might be related with low expression of p38á and p38β in the MAPK signal transduction pathway.

  13. Antinociceptive Interaction of Tramadol with Gabapentin in Experimental Mononeuropathic Pain.

    Science.gov (United States)

    Miranda, Hugo F; Noriega, Viviana; Prieto, Juan Carlos; Zanetta, Pilar; Castillo, Rodrigo; Aranda, Nicolás; Sierralta, Fernando

    2016-08-01

    Neuropathic pain is the result of injury to the nervous system, and different animal models have been established to meet the manifestations of neuropathy. The pharmacotherapy for neuropathic pain includes gabapentin and tramadol, but these are only partially effective when given alone. The aim of this study was to assess the antinociceptive interaction between both drugs using the isobolographic analysis and changes of the IL-1β concentration in a mouse model of neuropathic pain (partial sciatic nerve ligation or PSNL). The i.p. administration of gabapentin (5-100 mg/kg) or tramadol (12.5-100 mg/kg) displayed a dose-dependent antinociception in the hot plate assay of PSNL mice, and effects induced by gabapentin with tramadol were synergistic. Administration of gabapentin or tramadol reversed significantly the increase in the concentration of IL-1β induced by PSNL after either 7 or 14 days and their combination was significantly more potent in reversing the elevated concentration of IL-1β. The synergism obtained by the co-administration of gabapentin and tramadol is proposed to result from action on different mechanisms in pain pathways. Gabapentin or tramadol or their combination modulates the expression of pro-inflammatory cytokine, IL-1β, in a model of mice PSNL which could be due to an inhibition of glial function. © 2016 Nordic Association for the Publication of BCPT (former Nordic Pharmacological Society).

  14. Topical acetylsalicylic, salicylic acid and indomethacin suppress pain from experimental tissue acidosis in human skin.

    Science.gov (United States)

    Steen, K H; Reeh, P W; Kreysel, H W

    1995-09-01

    Topically applied acetylsalicylic acid (ASA), salicylic acid (SA) and indomethacin were tested in an experimental pain model that provides direct nociceptor excitation through cutaneous tissue acidosis. In 30 volunteers, sustained burning pain was produced in the palmar forearm through a continuous intradermal pressure infusion of a phosphate-buffered isotonic solution (pH 5.2). In 5 different, double-blind, randomized cross-over studies with 6 volunteers each, the flow rate of the syringe pump was individually adjusted to result in constant pain ratings of around 20% (50% in study 4) on a visual analog scale (VAS). The painful skin area was then covered with either placebo or the drugs which had been dissolved in diethylether. In the first study on 6 volunteers, ASA (60 mg/ml) or lactose (placebo) in diethylether (10 ml) was applied, using both arms at 3-day intervals. Both treatments resulted in sudden and profound pain relief due to the cooling effect of the evaporating ether. With lactose, however, the mean pain rating was restored close to the baseline within 6-8 min while, with ASA, it remained significantly depressed for the rest of the observation period (another 20 min). This deep analgesia was not accompanied by a loss of tactile sensation. The further studies served to show that indomethacin (4.5 mg/ml) and SA (60 mg/ml) were equally effective as ASA (each 92-96% pain reduction) and that the antinociceptive effects were due to local but not systemic actions, since ASA and SA dis not reach measurable plasma levels up to 3 h after topical applications. With a higher flow rate of acid buffer producing more intense pain (VAS 50%). ASA and SA were still able to significantly reduce the ratings by 90% or 84%, respectively. On the other hand, by increasing the flow rate by a factor of 2 on average, during the period of fully developed drug effect it was possible to overcome the pain suppression, which suggests a competitive mechanism of (acetyl-) salicylic

  15. Effects of experimental muscle pain on muscle activity and co-ordination during static and dynamic motor function.

    Science.gov (United States)

    Graven-Nielsen, T; Svensson, P; Arendt-Nielsen, L

    1997-04-01

    The relation between muscle pain, muscle activity, and muscle co-ordination is still controversial. The present human study investigates the influence of experimental muscle pain on resting, static, and dynamic muscle activity. In the resting and static experiments, the electromyography (EMG) activity and the contraction force of m. tibialis anterior were assessed before and after injection of 0.5 ml hypertonic saline (5%) into the same muscle. In the dynamic experiment, injections of 0.5 ml hypertonic saline (5%) were performed into either m. tibialis anterior (TA) or m. gastrocnemius (GA) and the muscle activity and co-ordination were investigated during gait on a treadmill by EMG recordings from m. TA and m. GA. At rest no evidence of EMG hyperactivity was found during muscle pain. The maximal voluntary contraction (MVC) during muscle pain was significantly lower than the control condition (P Fibromyalgia and Myofascial Pain. Elsevier, Amsterdam, 1993, pp. 311-327.) which predicts increased activity of antagonistic muscle and decreased activity of agonistic muscle during experimental and clinical muscle pain.

  16. The effects of blocking N/OFQ receptors on orofacial pain following experimental tooth movement in rats.

    Science.gov (United States)

    Shan, Di; He, Yuwei; Long, Hu; Zhou, Yang; Liu, He; Xu, Rui; Huang, Renhuan; Lai, Wenli

    2016-11-01

    The aim of this study was to determine the effects of nociceptin/orphanin FQ peptide receptor (N/OFQ receptor) antagonist on orofacial pain induced by experimental tooth movement in rats. A total of 36 male Sprague-Dawley rats weighing 200-300 g were divided into six groups: a control group, force group, force+saline intraperitoneal group, force+saline periodontal group, force+UFP-101 ([Nphe¹,Arg¹⁴,Lys¹⁵]N/OFQ-NH ₂ antagonist for N/OFQ receptor) intraperitoneal group, and force+UFP-1 01 periodontal group. Closed coil springs were ligated between the upper incisors and first molar to exert an orthodontic force (40 g) between the teeth. Injectable administration dosages were 30 μl saline or 30 μl saline containing 0.03 mg/kg UFP-1 01. Following the injections, orofacial pain levels were assessed through directed face grooming (mouth wiping). Statistical analyses were performed in SPSS 17.0 (Statistical Package for the Social Sciences) and p values less than 0.05 were considered as statistically significant. Orofacial pain levels were significantly higher in the force group than in the control group. Orofacial pain levels differed significantly between the force)group, force+saline periodontal group and force+UFP-101 periodontal group, but were similar between the control group, force+UFP-101 intraperitoneal group and force+saline intraperitoneal group. Moreover, orofacial pain levels did not differ between the force group, force+saline intraperitoneal group and force+UFP-1 01 intraperitoneal group. Periodontal, but not intraperitoneal, administration of UFP-101 could alleviate orofacial pain induced by experimental tooth movement in rats, suggesting that periodontal N/OFQ receptors participate in orofacial pain induced by experimental tooth movement.

  17. A comparative behavioural study of mechanical hypersensitivity in 2 pain models in rats and humans.

    Science.gov (United States)

    Reitz, Marie-Céline; Hrncic, Dragan; Treede, Rolf-Detlef; Caspani, Ombretta

    2016-06-01

    The assessment of pain sensitivity in humans has been standardized using quantitative sensory testing, whereas in animals mostly paw withdrawal thresholds to diverse stimuli are measured. This study directly compares tests used in quantitative sensory testing (pinpricks, pressure algometer) with tests used in animal studies (electronic von Frey test: evF), which we applied to the dorsal hind limbs of humans after high frequency stimulation and rats after tibial nerve transection. Both experimental models induce profound mechanical hypersensitivity. At baseline, humans and rats showed a similar sensitivity to evF with 0.2 mm diameter tips, but significant differences for other test stimuli (all P pain models (P pain sensitivity, but probe size and shape should be standardized. Hypersensitivity to blunt pressure-the leading positive sensory sign after peripheral nerve injury in humans-is a novel finding in the tibial nerve transection model. By testing outside the primary zone of nerve damage (rat) or activation (humans), our methods likely involve effects of central sensitization in both species.

  18. Is the Experience of Thermal Pain Genetics Dependent?

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    Emilia Horjales-Araujo

    2015-01-01

    Full Text Available It is suggested that genetic variations explain a significant portion of the variability in pain perception; therefore, increased understanding of pain-related genetic influences may identify new targets for therapies and treatments. The relative contribution of the different genes to the variance in clinical and experimental pain responses remains unknown. It is suggested that the genetic contributions to pain perception vary across pain modalities. For example, it has been suggested that more than 60% of the variance in cold pressor responses can be explained by genetic factors; in comparison, only 26% of the variance in heat pain responses is explained by these variations. Thus, the selection of pain model might markedly influence the magnitude of the association between the pain phenotype and genetic variability. Thermal pain sensation is complex with multiple molecular and cellular mechanisms operating alone and in combination within the peripheral and central nervous system. It is thus highly probable that the thermal pain experience is affected by genetic variants in one or more of the pathways involved in the thermal pain signaling. This review aims to present and discuss some of the genetic variations that have previously been associated with different experimental thermal pain models.

  19. Risk prediction model for knee pain in the Nottingham community: a Bayesian modelling approach.

    Science.gov (United States)

    Fernandes, G S; Bhattacharya, A; McWilliams, D F; Ingham, S L; Doherty, M; Zhang, W

    2017-03-20

    Twenty-five percent of the British population over the age of 50 years experiences knee pain. Knee pain can limit physical ability and cause distress and bears significant socioeconomic costs. The objectives of this study were to develop and validate the first risk prediction model for incident knee pain in the Nottingham community and validate this internally within the Nottingham cohort and externally within the Osteoarthritis Initiative (OAI) cohort. A total of 1822 participants from the Nottingham community who were at risk for knee pain were followed for 12 years. Of this cohort, two-thirds (n = 1203) were used to develop the risk prediction model, and one-third (n = 619) were used to validate the model. Incident knee pain was defined as pain on most days for at least 1 month in the past 12 months. Predictors were age, sex, body mass index, pain elsewhere, prior knee injury and knee alignment. A Bayesian logistic regression model was used to determine the probability of an OR >1. The Hosmer-Lemeshow χ 2 statistic (HLS) was used for calibration, and ROC curve analysis was used for discrimination. The OAI cohort from the United States was also used to examine the performance of the model. A risk prediction model for knee pain incidence was developed using a Bayesian approach. The model had good calibration, with an HLS of 7.17 (p = 0.52) and moderate discriminative ability (ROC 0.70) in the community. Individual scenarios are given using the model. However, the model had poor calibration (HLS 5866.28, p prediction model for knee pain, regardless of underlying structural changes of knee osteoarthritis, in the community using a Bayesian modelling approach. The model appears to work well in a community-based population but not in individuals with a higher risk for knee osteoarthritis, and it may provide a convenient tool for use in primary care to predict the risk of knee pain in the general population.

  20. Comparison of acceptance and distraction strategies in coping with experimentally induced pain

    Directory of Open Access Journals (Sweden)

    Moore H

    2015-03-01

    Full Text Available Hazel Moore,1 Ian Stewart,1 Dermot Barnes-Holmes,2 Yvonne Barnes-Holmes,2 Brian E McGuire1,31School of Psychology, National University of Ireland, Galway, 2Department of Psychology, National University of Ireland, Maynooth, 3Centre for Pain Research, National University of Ireland, Galway, IrelandBackground: This study compared an acceptance-based strategy with a control-based strategy (distraction in terms of the ability of participants to tolerate a painful stimulus, across two experiments. In addition, participants were either actively encouraged, or not, to link pain tolerance with pursuit of valued goals to examine the impact of pursuing a personally meaningful goal or value on the extent to which pain will be tolerated.Methods: Participants in experiment 1 (n=41 and experiment 2 (n=52 were equally assigned to acceptance or distraction protocols. Further, half the participants in each group generated examples from their own lives in which they had pursued a valued objective, while the other half did not. In experiment 2, the values focus was enhanced to examine the impact on pain tolerance.Results: There were no significant differences overall between the acceptance and distraction groups on pain tolerance in either experiment. However, in experiment 2, individuals classified as accepting in terms of general coping style and who were assigned to the acceptance strategy showed significantly better pain tolerance than accepting individuals who were in the distraction condition. Across both experiments, those with strong goal-driven values in both protocols were more tolerant of pain. Participants appeared to have more difficulty adhering to acceptance than to distraction as a strategy.Conclusion: Acceptance may be associated with better tolerance of pain, but may also be more difficult to operationalize than distraction in experimental studies. Matching coping style and coping strategy may be most effective, and enhancement of goal

  1. Are preoperative experimental pain assessments correlated with clinical pain outcomes after surgery?

    DEFF Research Database (Denmark)

    Sangesland, Anders; Støren, Carl; Vaegter, Henrik B.

    2017-01-01

    of surgery, QST variables, clinical pain outcome measure and main result. Results Most studies showed moderate to high risk of bias. Type of surgery investigated include 7 studies on total knee replacement, 5 studies on caesarean section, 4 studies on thoracic surgery, 2 studies on herniotomy, 2 studies......Background Pain after surgery is not uncommon with 30% of patients reporting moderate to severe postoperative pain. Early identification of patients prone to postoperative pain may be a step forward towards individualized pain medicine providing a basis for improved clinical management through......, and (3) the association between QST and pain after surgery was investigated. Forty-four unique studies were identified, with 30 studies on 2738 subjects meeting inclusion criteria. The methodological quality of the include studies was assessed and data extraction included study population, type...

  2. Experimental knee joint pain during strength training and muscle strength gain in healthy subjects: a randomized controlled trial.

    Science.gov (United States)

    Sørensen, T J; Langberg, H; Hodges, P W; Bliddal, H; Henriksen, M

    2012-01-01

    Knee joint pain and reduced quadriceps strength are cardinal symptoms in many knee pathologies. In people with painful knee pathologies, quadriceps exercise reduces pain, improves physical function, and increases muscle strength. A general assumption is that pain compromises muscle function and thus may prevent effective rehabilitation. This study evaluated the effects of experimental knee joint pain during quadriceps strength training on muscle strength gain in healthy individuals. Twenty-seven healthy untrained volunteers participated in a randomized controlled trial of quadriceps strengthening (3 times per week for 8 weeks). Participants were randomized to perform resistance training either during pain induced by injections of painful hypertonic saline (pain group, n = 13) or during a nonpainful control condition with injection of isotonic saline (control group, n = 14) into the infrapatellar fat pad. The primary outcome measure was change in maximal isokinetic muscle strength in knee extension/flexion (60, 120, and 180 degrees/second). The group who exercised with pain had a significantly larger improvement in isokinetic muscle strength at all angular velocities of knee extension compared to the control group. In knee flexion there were improvements in isokinetic muscle strength in both groups with no between-group differences. Experimental knee joint pain improved the training-induced gain in muscle strength following 8 weeks of quadriceps training. It remains to be studied whether knee joint pain has a positive effect on strength gain in patients with knee pathology. Copyright © 2012 by the American College of Rheumatology.

  3. Proteomic Identification of Altered Cerebral Proteins in the Complex Regional Pain Syndrome Animal Model

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    Francis Sahngun Nahm

    2014-01-01

    Full Text Available Background. Complex regional pain syndrome (CRPS is a rare but debilitating pain disorder. Although the exact pathophysiology of CRPS is not fully understood, central and peripheral mechanisms might be involved in the development of this disorder. To reveal the central mechanism of CRPS, we conducted a proteomic analysis of rat cerebrum using the chronic postischemia pain (CPIP model, a novel experimental model of CRPS. Materials and Methods. After generating the CPIP animal model, we performed a proteomic analysis of the rat cerebrum using a multidimensional protein identification technology, and screened the proteins differentially expressed between the CPIP and control groups. Results. A total of 155 proteins were differentially expressed between the CPIP and control groups: 125 increased and 30 decreased; expressions of proteins related to cell signaling, synaptic plasticity, regulation of cell proliferation, and cytoskeletal formation were increased in the CPIP group. However, proenkephalin A, cereblon, and neuroserpin were decreased in CPIP group. Conclusion. Altered expression of cerebral proteins in the CPIP model indicates cerebral involvement in the pathogenesis of CRPS. Further study is required to elucidate the roles of these proteins in the development and maintenance of CRPS.

  4. Proteomic identification of altered cerebral proteins in the complex regional pain syndrome animal model.

    Science.gov (United States)

    Nahm, Francis Sahngun; Park, Zee-Yong; Nahm, Sang-Soep; Kim, Yong Chul; Lee, Pyung Bok

    2014-01-01

    Complex regional pain syndrome (CRPS) is a rare but debilitating pain disorder. Although the exact pathophysiology of CRPS is not fully understood, central and peripheral mechanisms might be involved in the development of this disorder. To reveal the central mechanism of CRPS, we conducted a proteomic analysis of rat cerebrum using the chronic postischemia pain (CPIP) model, a novel experimental model of CRPS. After generating the CPIP animal model, we performed a proteomic analysis of the rat cerebrum using a multidimensional protein identification technology, and screened the proteins differentially expressed between the CPIP and control groups. Results. A total of 155 proteins were differentially expressed between the CPIP and control groups: 125 increased and 30 decreased; expressions of proteins related to cell signaling, synaptic plasticity, regulation of cell proliferation, and cytoskeletal formation were increased in the CPIP group. However, proenkephalin A, cereblon, and neuroserpin were decreased in CPIP group. Altered expression of cerebral proteins in the CPIP model indicates cerebral involvement in the pathogenesis of CRPS. Further study is required to elucidate the roles of these proteins in the development and maintenance of CRPS.

  5. The rat intervertebral disk degeneration pain model: relationships between biological and structural alterations and pain.

    Science.gov (United States)

    Kim, Jae-Sung; Kroin, Jeffrey S; Li, Xin; An, Howard S; Buvanendran, Asokumar; Yan, Dongyao; Tuman, Kenneth J; van Wijnen, Andre J; Chen, Di; Im, Hee-Jeong

    2011-01-01

    Degeneration of the interverterbral disk is as a cause of low-back pain is increasing. To gain insight into relationships between biological processes, structural alterations and behavioral pain, we created an animal model in rats. Disk degeneration was induced by removal of the nucleus pulposus (NP) from the lumbar disks (L4/L5 and L5/L6) of Sprague Dawley rats using a 0.5-mm-diameter microsurgical drill. The degree of primary hyperalgesia was assessed by using an algometer to measure pain upon external pressure on injured lumbar disks. Biochemical and histological assessments and radiographs of injured disks were used for evaluation. We investigated therapeutic modulation of chronic pain by administering pharmaceutical drugs in this animal model. After removal of the NP, pressure hyperalgesia developed over the lower back. Nine weeks after surgery we observed damaged or degenerated disks with proteoglycan loss and narrowing of disk height. These biological and structural changes in disks were closely related to the sustained pain hyperalgesia. A high dose of morphine (6.7 mg/kg) resulted in effective pain relief. However, high doses of pregabalin (20 mg/kg), a drug that has been used for treatment of chronic neuropathic pain, as well as the anti-inflammatory drugs celecoxib (50 mg/kg; a selective inhibitor of cyclooxygenase 2 (COX-2)) and ketorolac (20 mg/kg; an inhibitor of COX-1 and COX-2), did not have significant antihyperalgesic effects in our disk injury animal model. Although similarities in gene expression profiles suggest potential overlap in chronic pain pathways linked to disk injury or neuropathy, drug-testing results suggest that pain pathways linked to these two chronic pain conditions are mechanistically distinct. Our findings provide a foundation for future research on new therapeutic interventions that can lead to improvements in the treatment of patients with back pain due to disk degeneration.

  6. Electrical stimulation of the insular cortex as a novel target for the relief of refractory pain: An experimental approach in rodents.

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    Dimov, Luiz Fabio; Toniolo, Elaine Flamia; Alonso-Matielo, Heloísa; de Andrade, Daniel Ciampi; Garcia-Larrea, Luis; Ballester, Gerson; Teixeira, Manoel Jacobsen; Dale, Camila Squarzoni

    2018-07-02

    Cortical electrical stimulation (CES) has shown to be an effective therapeutic alternative for neuropathic pain refractory to pharmacological treatment. The primary motor cortex(M1) was the main cortical target used in the vast majority of both invasive and non-invasive studies. Despite positive results M1-based approaches still fail to relieve pain in a significant proportion of individuals. It has been advocated that the direct stimulation of cortical areas directly implicated in the central integration of pain could increase the efficacy of analgesic brain stimulation. Here, we evaluated the behavioral effects of electrical stimulation of the insular cortex (ESI) on pain sensitivity in an experimental rat model of peripheral neuropathy, and have described the pathways involved. Animals underwent chronic constriction of the sciatic nerve in the right hind limb and had concentric electrodes implanted in the posterior dysranular insular cortex. Mechanical nociception responses were evaluated before and at the end of a 15-min session of ESI (60Hz, 210μs, 1V). ESI reversed mechanical hypersensitivity in the paw contralateral to the brain hemisphere stimulated, without inducing motor impairment in the open-field test. Pharmacological blockade of μ-opioid (MOR) or type 1-cannabinoid receptors (CB1R) abolished ESI-induced antinociceptive effects. Evaluation of CB1R and MOR spatial expression demonstrated differential modulation of CB1R and MOR in the periaqueductal gray matter (PAG) of ESI-treated rats in sub-areas involved in pain processing/modulation. These results indicate that ESI induces antinociception by functionally modulating opioid and cannabinoid systems in the PAG pain circuitry in rats with experimentally induced neuropathic pain. Copyright © 2017 Elsevier B.V. All rights reserved.

  7. Pain management: a review of organisation models with integrated processes for the management of pain in adult cancer patients.

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    Brink-Huis, Anita; van Achterberg, Theo; Schoonhoven, Lisette

    2008-08-01

    This paper reports a review of the literature conducted to identify organisation models in cancer pain management that contain integrated care processes and describe their effectiveness. Pain is experienced by 30-50% of cancer patients receiving treatment and by 70-90% of those with advanced disease. Efforts to improve pain management have been made through the development and dissemination of clinical guidelines. Early improvements in pain management were focussed on just one or two single processes such as pain assessment and patient education. Little is known about organisational models with multiple integrated processes throughout the course of the disease trajectory and concerning all stages of the care process. Systematic review. The review involved a systematic search of the literature, published between 1986-2006. Subject-specific keywords used to describe patients, disease, pain management interventions and integrated care processes, relevant for this review were selected using the thesaurus of the databases. Institutional models, clinical pathways and consultation services are three alternative models for the integration of care processes in cancer pain management. A clinical pathway is a comprehensive institutionalisation model, whereas a pain consultation service is a 'stand-alone' model that can be integrated in a clinical pathway. Positive patient and process outcomes have been described for all three models, although the level of evidence is generally low. Evaluation of the quality of pain management must involve standardised measurements of both patient and process outcomes. We recommend the development of policies for referrals to a pain consultation service. These policies can be integrated within a clinical pathway. To evaluate the effectiveness of pain management models standardised outcome measures are needed.

  8. Historical development of epistemology and the study of pain: Place of neuromodulation of electroacupuncture in the experimental pain research

    Directory of Open Access Journals (Sweden)

    Bárbara B. Garrido-Suárez

    2013-10-01

    Full Text Available Despite the diffusion of acupuncture and its related techniques in Cuba and the World, its mechanism of action is still controversial, being considered by the most sceptics as placebo or some kind oriental myth, and it only should by related to this subjects as a matter of cultural-historical elements and not to science. The purpose of this revision is to characterize the pain sensation, after a critical analysis of the different philosophical streams related to the human knowledge and its expression in the historical evolution of the algology. On the other hand, to emphasize the importance of electroacupuncture-induced neuro-modulation in the field of experimental pain researches. In this content will be analyzed the concept of Khun paradigm and his ideas about the structure of scientific revolution in the theory of gates control and the explosion of pain researches in the last decades. It will related the introduction to acupuncture and its techniques in pain clinics, with scientific context of the historical moment. In addition, a space will be dedicated to the topic of complementary and alternative medicine on the century of evidence based medicine, given its scientific needs of validation in ours times.

  9. Social Modeling Influences on Pain Experience and Behaviour.

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    Craig, Kenneth D.

    The impact of exposure to social models displaying variably tolerant pain behaviour on observers' expressions of pain is examined. Findings indicate substantial effects on verbal reports of pain, avoidance behaviour, psychophysiological indices, power function parameters, and sensory decision theory indices. Discussion centers on how social models…

  10. Comparison of burrowing and stimuli-evoked pain behaviors as end-points in rat models of inflammatory pain and peripheral neuropathic pain

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    Arjun eMuralidharan

    2016-05-01

    Full Text Available Establishment and validation of ethologically-relevant, non-evoked behavioral end-points as surrogate measures of spontaneous pain in rodent pain models has been proposed as a means to improve preclinical to clinical research translation in the pain field. Here, we compared the utility of burrowing behavior with hypersensitivity to applied mechanical stimuli for pain assessment in rat models of chronic inflammatory and peripheral neuropathic pain. Briefly, groups of male Sprague-Dawley rats were habituated to the burrowing environment and trained over a 5-day period. Rats that burrowed ≤450g of gravel on any two days of the individual training phase were excluded from the study. The remaining rats received either a unilateral intraplantar injection of Freund’s complete adjuvant (FCA or saline, or underwent unilateral chronic constriction injury (CCI of the sciatic nerve- or sham-surgery. Baseline burrowing behavior and evoked pain behaviors were assessed prior to model induction, and twice-weekly until study completion on day 14. For FCA- and CCI-rats, but not the corresponding groups of sham-rats, evoked mechanical hypersensitivity developed in a temporal manner in the ipsilateral hindpaws. Although burrowing behavior also decreased in a temporal manner for both FCA- and CCI-rats, there was considerable inter-animal variability. By contrast, mechanical hyperalgesia and mechanical allodynia in the ipsilateral hindpaws of FCA- and CCI-rats respectively, exhibited minimal inter-animal variability. Our data collectively show that burrowing behavior is altered in rodent models of chronic inflammatory pain and peripheral neuropathic pain. However, large group sizes are needed to ensure studies are adequately powered due to considerable inter-animal variability.

  11. Psychological Factors Predict Local and Referred Experimental Muscle Pain: A Cluster Analysis in Healthy Adults

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    Lee, Jennifer E.; Watson, David; Frey-Law, Laura A.

    2012-01-01

    Background Recent studies suggest an underlying three- or four-factor structure explains the conceptual overlap and distinctiveness of several negative emotionality and pain-related constructs. However, the validity of these latent factors for predicting pain has not been examined. Methods A cohort of 189 (99F; 90M) healthy volunteers completed eight self-report negative emotionality and pain-related measures (Eysenck Personality Questionnaire-Revised; Positive and Negative Affect Schedule; State-Trait Anxiety Inventory; Pain Catastrophizing Scale; Fear of Pain Questionnaire; Somatosensory Amplification Scale; Anxiety Sensitivity Index; Whiteley Index). Using principal axis factoring, three primary latent factors were extracted: General Distress; Catastrophic Thinking; and Pain-Related Fear. Using these factors, individuals clustered into three subgroups of high, moderate, and low negative emotionality responses. Experimental pain was induced via intramuscular acidic infusion into the anterior tibialis muscle, producing local (infusion site) and/or referred (anterior ankle) pain and hyperalgesia. Results Pain outcomes differed between clusters (multivariate analysis of variance and multinomial regression), with individuals in the highest negative emotionality cluster reporting the greatest local pain (p = 0.05), mechanical hyperalgesia (pressure pain thresholds; p = 0.009) and greater odds (2.21 OR) of experiencing referred pain compared to the lowest negative emotionality cluster. Conclusion Our results provide support for three latent psychological factors explaining the majority of the variance between several pain-related psychological measures, and that individuals in the high negative emotionality subgroup are at increased risk for (1) acute local muscle pain; (2) local hyperalgesia; and (3) referred pain using a standardized nociceptive input. PMID:23165778

  12. A Model-Based Approach for Joint Analysis of Pain Intensity and Opioid Consumption in Postoperative Pain

    DEFF Research Database (Denmark)

    Juul, Rasmus V; Knøsgaard, Katrine R; Olesen, Anne E

    2016-01-01

    Joint analysis of pain intensity and opioid consumption is encouraged in trials of postoperative pain. However, previous approaches have not appropriately addressed the complexity of their interrelation in time. In this study, we applied a non-linear mixed effects model to simultaneously study pain...... intensity and opioid consumption in a 4-h postoperative period for 44 patients undergoing percutaneous kidney stone surgery. Analysis was based on 748 Numerical Rating Scale (NRS) scores of pain intensity and 51 observed morphine and oxycodone dosing events. A joint model was developed to describe...... the recurrent pattern of four key phases determining the development of pain intensity and opioid consumption in time; (A) Distribution of pain intensity scores which followed a truncated Poisson distribution with time-dependent mean score ranging from 0.93 to 2.45; (B) Probability of transition to threshold...

  13. Preliminary findings of cerebral responses on transcutaneous vagal nerve stimulation on experimental heat pain.

    Science.gov (United States)

    Usichenko, Taras; Laqua, René; Leutzow, Bianca; Lotze, Martin

    2017-02-01

    Transcutaneous vagal nerve stimulation (TVNS) is a promising complementary method of pain relief. However, the neural networks associated with its analgesic effects are still to be elucidated. Therefore, we conducted two functional magnetic resonance imaging (fMRI) sessions, in a randomized order, with twenty healthy subjects who were exposed to experimental heat pain stimulation applied to the right forearm using a Contact Heat-Evoked Potential Stimulator. While in one session TVNS was administered bilaterally to the concha auriculae with maximal, non-painful intensity, the stimulation device was switched off in the other session (placebo condition). Pain thresholds were measured before and after each session. Heat stimulation elicited fMRI activation in cerebral pain processing regions. Activation magnitude in the secondary somatosensory cortex, posterior insula, anterior cingulate and caudate nucleus was associated with heat stimulation without TVNS. During TVNS, this association was only seen for the right anterior insula. TVNS decreased fMRI signals in the anterior cingulate cortex in comparison with the placebo condition; however, there was no relevant pain reducing effect over the group as a whole. In contrast, TVNS compared to the placebo condition showed an increased activation in the primary motor cortex, contralateral to the site of heat stimulation, and in the right amygdala. In conclusion, in the protocol used here, TVNS specifically modulated the cerebral response to heat pain, without having a direct effect on pain thresholds.

  14. Does experimental low back pain change posteroanterior lumbar spinal stiffness and trunk muscle activity? A randomized crossover study.

    Science.gov (United States)

    Wong, Arnold Y L; Parent, Eric C; Prasad, Narasimha; Huang, Christopher; Chan, K Ming; Kawchuk, Gregory N

    2016-05-01

    While some patients with low back pain demonstrate increased spinal stiffness that decreases as pain subsides, this observation is inconsistent. Currently, the relation between spinal stiffness and low back pain remains unclear. This study aimed to investigate the effects of experimental low back pain on temporal changes in posteroanterior spinal stiffness and concurrent trunk muscle activity. In separate sessions five days apart, nine asymptomatic participants received equal volume injections of hypertonic or isotonic saline in random order into the L3-L5 interspinous ligaments. Pain intensity, spinal stiffness (global and terminal stiffness) at the L3 level, and the surface electromyographic activity of six trunk muscles were measured before, immediately after, and 25-minute after injections. These outcome measures under different saline conditions were compared by generalized estimating equations. Compared to isotonic saline injections, hypertonic saline injections evoked significantly higher pain intensity (mean difference: 5.7/10), higher global (mean difference: 0.73N/mm) and terminal stiffness (mean difference: 0.58N/mm), and increased activity of four trunk muscles during indentation (Ppain subsided. While previous clinical research reported inconsistent findings regarding the association between spinal stiffness and low back pain, our study revealed that experimental pain caused temporary increases in spinal stiffness and concurrent trunk muscle co-contraction during indentation, which helps explain the temporal relation between spinal stiffness and low back pain observed in some clinical studies. Our results substantiate the role of spinal stiffness assessments in monitoring back pain progression. Copyright © 2016 Elsevier Ltd. All rights reserved.

  15. Rat Experimental Model of Myocardial Ischemia/Reperfusion Injury: An Ethical Approach to Set up the Analgesic Management of Acute Post-Surgical Pain

    Science.gov (United States)

    Ciuffreda, Maria Chiara; Tolva, Valerio; Casana, Renato; Gnecchi, Massimiliano; Vanoli, Emilio; Spazzolini, Carla; Roughan, John; Calvillo, Laura

    2014-01-01

    Rationale During the past 30 years, myocardial ischemia/reperfusion injury in rodents became one of the most commonly used model in cardiovascular research. Appropriate pain-prevention appears critical since it may influence the outcome and the results obtained with this model. However, there are no proper guidelines for pain management in rats undergoing thoracic surgery. Accordingly, we evaluated three analgesic regimens in cardiac ischemia/reperfusion injury. This study was strongly focused on 3R’s ethic principles, in particular the principle of Reduction. Methods Rats undergoing surgery were treated with pre-surgical tramadol (45 mg/kg intra-peritoneal), or carprofen (5 mg/kg sub-cutaneous), or with pre-surgical administration of carprofen followed by 2 post-surgery tramadol injections (multi-modal group). We assessed behavioral signs of pain and made a subjective evaluation of stress and suffering one and two hours after surgery. Results Multi-modal treatment significantly reduced the number of signs of pain compared to carprofen alone at both the first hour (61±42 vs 123±47; pCarprofen alone was more effective at the second hour post-surgery when signs of pain reduced to 74±24 from 113±40 in the first hour (pcarprofen and tramadol groups, respectively (pcarprofen and tramadol was more effective in preventing pain during the second hour after surgery compared with both tramadol or carprofen. Our results suggest that the combination of carprofen and tramadol represent the best therapy to prevent animal pain after myocardial ischemia/reperfusion. We obtained our results accordingly with the ethical principle of Reduction. PMID:24756074

  16. Traumatization and chronic pain: a further model of interaction

    Directory of Open Access Journals (Sweden)

    Egloff N

    2013-11-01

    Full Text Available Niklaus Egloff,1 Anna Hirschi,2 Roland von Känel1 1Department of General Internal Medicine, Division of Psychosomatic Medicine, Inselspital, University Hospital, Bern, Switzerland; 2Outpatient Clinic for Victims of Torture and War, Swiss Red Cross, Bern-Wabern, Switzerland Abstract: Up to 80% of patients with severe posttraumatic stress disorder are suffering from “unexplained” chronic pain. Theories about the links between traumatization and chronic pain have become the subject of increased interest over the last several years. We will give a short summary about the existing interaction models that emphasize particularly psychological and behavioral aspects of this interaction. After a synopsis of the most important psychoneurobiological mechanisms of pain in the context of traumatization, we introduce the hypermnesia–hyperarousal model, which focuses on two psychoneurobiological aspects of the physiology of learning. This hypothesis provides an answer to the hitherto open question about the origin of pain persistence and pain sensitization following a traumatic event and also provides a straightforward explanatory model for educational purposes. Keywords: posttraumatic stress disorder, chronic pain, hypermnesia, hypersensitivity, traumatization

  17. Experimental pain leads to reorganisation of trapezius electromyography during computer work with active and passive pauses

    DEFF Research Database (Denmark)

    Samani, Afshin; Holtermann, Andreas; Søgaard, Karen

    2009-01-01

    The aim of this laboratory study was to investigate acute effects of experimental muscle pain on spatial electromyographic (EMG) activity of the trapezius muscle during computer work with active and passive pauses. Twelve healthy male subjects performed four sessions of computer work for 2 min...... in one day, with passive (relax) and active (30% maximum voluntary contraction of shoulder elevation) pauses given every 40 s without and with presence of experimental pain. Surface EMG signals were recorded from four parts of the trapezius. The centroid of exposure variation analysis along the time axis...... was lower during computer work with active pauses when compared with passive one in all muscle parts (P

  18. Psychosocial Pain Management Moderation: The Limit, Activate, and Enhance Model.

    Science.gov (United States)

    Day, Melissa A; Ehde, Dawn M; Jensen, Mark P

    2015-10-01

    There is a growing emphasis in the pain literature on understanding the following second-order research questions: Why do psychosocial pain treatments work? For whom do various treatments work? This critical review summarizes research that addresses the latter question and proposes a moderation model to help guide future research. A theoretical moderation framework for matching individuals to specific psychosocial pain interventions has been lacking. However, several such frameworks have been proposed in the broad psychotherapy and implementation science literature. Drawing on these theories and adapting them specifically for psychosocial pain treatment, here we propose a Limit, Activate, and Enhance model of pain treatment moderation. This model is unique in that it includes algorithms not only for matching treatments on the basis of patient weaknesses but also for directing patients to interventions that build on their strengths. Critically, this model provides a basis for specific a priori hypothesis generation, and a selection of the possible hypotheses drawn from the model are proposed and discussed. Future research considerations are presented that could refine and expand the model based on theoretically driven empirical evidence. The Limit, Activate, and Enhance model presented here is a theoretically derived framework that provides an a priori basis for hypothesis generation regarding psychosocial pain treatment moderators. The model will advance moderation research via its unique focus on matching patients to specific treatments that (1) limit maladaptive responses, (2) activate adaptive responses, and (3) enhance treatment outcomes based on patient strengths and resources. Copyright © 2015 American Pain Society. Published by Elsevier Inc. All rights reserved.

  19. Production of consistent pain by intermittent infusion of sterile 5% hypertonic saline, followed by decrease of pain with cryotherapy.

    Science.gov (United States)

    Long, Blaine C; Knight, Kenneth L; Hopkins, Ty; Parcell, Allen C; Feland, J Brent

    2012-08-01

    It is suggested that postinjury pain is difficult to examine; thus, investigators have developed experimental pain models. To minimize pain, cryotherapy (cryo) is applied, but reports on its effectiveness are limited. To investigate a pain model for the anterior knee and examine cryo in reducing the pain. Controlled laboratory study. Therapeutic modality laboratory. 30 physically active healthy male subjects who were free from any lower extremity orthopedic, neurological, cardiovascular, or endocrine pathologies. Perceived pain was measured every minute. Surface temperature was also assessed in the center of the patella and the popliteal fossa. There was a significant interaction between group and time (F68,864 = 3.0, P = .0001). At the first minute, there was no difference in pain between the 3 groups (saline/cryo = 4.80 ± 4.87 mm, saline/sham = 2.80 ± 3.55 mm, no saline/cryo = 4.00 ± 3.33 mm). During the first 5 min, pain increased from 4.80 ± 4.87 to 45.90 ± 21.17 mm in the saline/cryo group and from 2.80 ± 3.55 to 31.10 ± 20.25 mm in the saline/sham group. Pain did not change within the no-saline/cryo group, 4.00 ± 3.33 to 1.70 ± 1.70 mm. Pain for the saline/sham group remained constant for 17 min. Cryo decreased pain for 16 min in the saline/cryo group. There was no difference in preapplication surface temperature between or within each group. No change in temperature occurred within the saline/sham. Cooling and rewarming were similar in both cryo groups. Ambient temperature fluctuated less than 1°C during data collection. Intermittent infusion of sterile 5% hypertonic saline may be a useful experimental pain model in establishing a constant level of pain in a controlled laboratory setting. Cryotherapy decreased the induced anterior knee pain for 16 min.

  20. Hypnosis and Local Anesthesia for Dental Pain Relief-Alternative or Adjunct Therapy?-A Randomized, Clinical-Experimental Crossover Study.

    Science.gov (United States)

    Wolf, Thomas Gerhard; Wolf, Dominik; Callaway, Angelika; Below, Dagna; d'Hoedt, Bernd; Willershausen, Brita; Daubländer, Monika

    2016-01-01

    This prospective randomized clinical crossover trial was designed to compare hypnosis and local anesthesia for experimental dental pain relief. Pain thresholds of the dental pulp were determined. A targeted standardized pain stimulus was applied and rated on the Visual Analogue Scale (0-10). The pain threshold was lower under hypnosis (58.3 ± 17.3, p local anesthesia. The pain stimulus was scored higher under hypnosis (3.9 ± 3.8) than with local anesthesia (0.0, p Local anesthesia was superior to hypnosis and is a safe and effective method for pain relief in dentistry. Hypnosis seems to produce similar effects observed under sedation. It can be used in addition to local anesthesia and in individual cases as an alternative for pain control in dentistry.

  1. Temporal characteristics of cold pain perception.

    Science.gov (United States)

    Frölich, Michael A; Bolding, Mark S; Cutter, Gary R; Ness, Timothy J; Zhang, Kui

    2010-08-09

    Adaptation to a sustained stimulus is an important phenomenon in psychophysical experiments. When studying the response to an experimental task, the investigator has to account for the change in perceived stimulus intensity with repeated stimulus application and, if the stimulus is sustained, for the change in intensity during the presentation. An example of a sustained stimulus is the cold pressor task (CPT). The task has been used both as an experimental pain task and to study cardiovascular physiology. In functional imaging research, the CPT has been used to evaluate cognitive processing of a noxious stimulus. Investigators typically model the stimulus in a block design as a categorical (on-off) stimulus and do not account for a temporal change in stimulus perception. If the perceived stimulus changes over time, the results may be misleading. Therefore, we characterized the time course of cold pain in human volunteers and developed a model of the temporal characteristics of perceived cold pain. Fifteen healthy participants underwent cold pain testing by immersing their right foot into a container filled with ice water (2 degrees C) for 30s alternating with a 30s immersion into a container filled with tepid water 32 degrees C (control). Participants rated the pain intensity using an electronic slide algometer. Using a mixed general linear model (effectively a polynomial regression model), we determined that pain ratings follow a crescendo-decrescendo pattern that can be described well using a quadratic model. We conclude that the time course of quantitative perception differs fundamentally from the time course of stimulus presentation. This may be important when looking for the physiological correlates of perception as opposed to the presence of a stimulus per se. Copyright 2010 Elsevier Ireland Ltd. All rights reserved.

  2. Effect of family presence on pain and anxiety during invasive nursing procedures in an emergency department: A randomized controlled experimental study.

    Science.gov (United States)

    İşlekdemir, Burcu; Kaya, Nurten

    2016-01-01

    Patients generally prefer to have their family present during medical or nursing interventions. Family presence is assumed to reduce anxiety, especially during painful interventions. This study employed a randomized controlled experimental design to determine the effects of family presence on pain and anxiety during invasive nursing procedures. The study population consisted of patients hospitalized in the observation unit of the internal medicine section in the emergency department of a university hospital. The sample comprised 138 patients assigned into the experimental and control groups by drawing lots. The invasive nursing procedure was carried out in the presence of family members, for members of the experimental group, and without family members, for members of the control group. Thus, the effects of family presence on pain and anxiety during the administration of an invasive nursing procedure to patients were analyzed. The results showed that members of the experimental and control groups did not differ with respect to the pain and state anxiety scores during the intervention. Family presence does not influence the participants' pain and anxiety during an invasive nursing procedure. Thus, the decision regarding family presence during such procedures should be based on patient preference. Copyright © 2015 Elsevier Ltd. All rights reserved.

  3. Voluntary wheel running delays disease onset and reduces pain hypersensitivity in early experimental autoimmune encephalomyelitis (EAE).

    Science.gov (United States)

    Benson, Curtis; Paylor, John W; Tenorio, Gustavo; Winship, Ian; Baker, Glen; Kerr, Bradley J

    2015-09-01

    Multiple sclerosis (MS) is classically defined by motor deficits, but it is also associated with the secondary symptoms of pain, depression, and anxiety. Up to this point modifying these secondary symptoms has been difficult. There is evidence that both MS and the animal model experimental autoimmune encephalomyelitis (EAE), commonly used to study the pathophysiology of the disease, can be modulated by exercise. To examine whether limited voluntary wheel running could modulate EAE disease progression and the co-morbid symptoms of pain, mice with EAE were allowed access to running wheels for 1h every day. Allowing only 1h every day of voluntary running led to a significant delay in the onset of clinical signs of the disease. The development of mechanical allodynia was assessed using Von Frey hairs and indicated that wheel running had a modest positive effect on the pain hypersensitivity associated with EAE. These behavioral changes were associated with reduced numbers of cFOS and phosphorylated NR1 positive cells in the dorsal horn of the spinal cord compared to no-run EAE controls. In addition, within the dorsal horn, voluntary wheel running reduced the number of infiltrating CD3(+) T-cells and reduced the overall levels of Iba1 immunoreactivity. Using high performance liquid chromatography (HPLC), we observed that wheel-running lead to significant changes in the spinal cord levels of the antioxidant glutathione. Oxidative stress has separately been shown to contribute to EAE disease progression and neuropathic pain. Together these results indicate that in mice with EAE, voluntary motor activity can delay the onset of clinical signs and reduce pain symptoms associated with the disease. Copyright © 2015 Elsevier Inc. All rights reserved.

  4. Fear of pain potentiates nocebo hyperalgesia

    Directory of Open Access Journals (Sweden)

    Aslaksen PM

    2015-10-01

    Full Text Available Per M Aslaksen,1 Peter S Lyby2 1Department of Psychology, Research Group for Cognitive Neuroscience, The Faculty of Health Sciences, University of Tromsø, The Arctic University of Norway, Tromsø, Norway; 2Catosenteret Rehabilitation Center, Son, Norway Abstract: Nocebo hyperalgesia has received sparse experimental attention compared to placebo analgesia. The aim of the present study was to investigate if personality traits and fear of pain could predict experimental nocebo hyperalgesia. One hundred and eleven healthy volunteers (76 females participated in an experimental study in which personality traits and fear of pain were measured prior to induction of thermal heat pain. Personality traits were measured by the Big-Five Inventory-10. Fear of pain was measured by the Fear of Pain Questionnaire III. Heat pain was induced by a PC-controlled thermode. Pain was measured by a computerized visual analog scale. Stress levels during the experiment were measured by numerical rating scales. The participants were randomized to a Nocebo group or to a no-treatment Natural History group. The results revealed that pain and stress levels were significantly higher in the Nocebo group after nocebo treatment. Mediation analysis showed that higher levels of the Fear of Pain Questionnaire III factor "fear of medical pain" significantly increased stress levels after nocebo treatment and that higher stress levels were associated with increased nocebo hyperalgesic responses. There were no significant associations between any of the personality factors and the nocebo hyperalgesic effect. The results from the present study suggest that dispositional fear of pain might be a useful predictor for nocebo hyperalgesia and emotional states concomitant with expectations of increased pain. Furthermore, measurement of traits that are specific to pain experience is probably better suited for prediction of nocebo hyperalgesic responses compared to broad measures of personality

  5. Patient-Clinician Communication About Pain: A Conceptual Model and Narrative Review.

    Science.gov (United States)

    Henry, Stephen G; Matthias, Marianne S

    2018-02-01

    Productive patient-clinician communication is an important component of effective pain management, but we know little about how patients and clinicians actually talk about pain in clinical settings and how it might be improved to produce better patient outcomes. The objective of this review was to create a conceptual model of patient-clinician communication about noncancer pain, review and synthesize empirical research in this area, and identify priorities for future research. A conceptual model was developed that drew on existing pain and health communication research. CINAHL, EMBASE, and PubMed were searched to find studies reporting empirical data on patient-clinician communication about noncancer pain; results were supplemented with manual searches. Studies were categorized and analyzed to identify crosscutting themes and inform model development. The conceptual model comprised the following components: contextual factors, clinical interaction, attitudes and beliefs, and outcomes. Thirty-nine studies met inclusion criteria and were analyzed based on model components. Studies varied widely in quality, methodology, and sample size. Two provisional conclusions were identified: contrary to what is often reported in the literature, discussions about analgesics are most frequently characterized by patient-clinician agreement, and self-presentation during patient-clinician interactions plays an important role in communication about pain and opioids. Published studies on patient-clinician communication about noncancer pain are few and diverse. The conceptual model presented here can help to identify knowledge gaps and guide future research on communication about pain. Investigating the links between communication and pain-related outcomes is an important priority for future research. © 2018 American Academy of Pain Medicine. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com

  6. A Bayesian perspective on sensory and cognitive integration in pain perception and placebo analgesia.

    Directory of Open Access Journals (Sweden)

    Davide Anchisi

    Full Text Available The placebo effect is a component of any response to a treatment (effective or inert, but we still ignore why it exists. We propose that placebo analgesia is a facet of pain perception, others being the modulating effects of emotions, cognition and past experience, and we suggest that a computational understanding of pain may provide a unifying explanation of these phenomena. Here we show how Bayesian decision theory can account for such features and we describe a model of pain that we tested against experimental data. Our model not only agrees with placebo analgesia, but also predicts that learning can affect pain perception in other unexpected ways, which experimental evidence supports. Finally, the model can also reflect the strategies used by pain perception, showing that modulation by disparate factors is intrinsic to the pain process.

  7. Viewing pictures of a romantic partner reduces experimental pain: involvement of neural reward systems.

    Science.gov (United States)

    Younger, Jarred; Aron, Arthur; Parke, Sara; Chatterjee, Neil; Mackey, Sean

    2010-10-13

    The early stages of a new romantic relationship are characterized by intense feelings of euphoria, well-being, and preoccupation with the romantic partner. Neuroimaging research has linked those feelings to activation of reward systems in the human brain. The results of those studies may be relevant to pain management in humans, as basic animal research has shown that pharmacologic activation of reward systems can substantially reduce pain. Indeed, viewing pictures of a romantic partner was recently demonstrated to reduce experimental thermal pain. We hypothesized that pain relief evoked by viewing pictures of a romantic partner would be associated with neural activations in reward-processing centers. In this functional magnetic resonance imaging (fMRI) study, we examined fifteen individuals in the first nine months of a new, romantic relationship. Participants completed three tasks under periods of moderate and high thermal pain: 1) viewing pictures of their romantic partner, 2) viewing pictures of an equally attractive and familiar acquaintance, and 3) a word-association distraction task previously demonstrated to reduce pain. The partner and distraction tasks both significantly reduced self-reported pain, although only the partner task was associated with activation of reward systems. Greater analgesia while viewing pictures of a romantic partner was associated with increased activity in several reward-processing regions, including the caudate head, nucleus accumbens, lateral orbitofrontal cortex, amygdala, and dorsolateral prefrontal cortex--regions not associated with distraction-induced analgesia. The results suggest that the activation of neural reward systems via non-pharmacologic means can reduce the experience of pain.

  8. [Neither Descartes nor Freud? current pain models in psychosomatic medicine].

    Science.gov (United States)

    Egloff, N; Egle, U T; von Känel, R

    2008-05-14

    Models explaining chronic pain based on the mere presence or absence of peripheral somatic findings or which view pain of psychological origin when there is no somatic explanation, have their shortcomings. Current scientific knowledge calls for distinct pain concepts, which integrate neurobiological and neuropsychological aspects of pain processing.

  9. Investigating Circadian Rhythmicity in Pain Sensitivity Using a Neural Circuit Model for Spinal Cord Processing of Pain

    DEFF Research Database (Denmark)

    Crodelle, Jennifer; Piltz, Sofia Helena; Booth, Victoria

    2017-01-01

    Primary processing of painful stimulation occurs in the dorsal horn of the spinal cord. In this article, we introduce mathematical models of the neural circuitry in the dorsal horn responsible for processing nerve fiber inputs from noxious stimulation of peripheral tissues and generating the resu......Primary processing of painful stimulation occurs in the dorsal horn of the spinal cord. In this article, we introduce mathematical models of the neural circuitry in the dorsal horn responsible for processing nerve fiber inputs from noxious stimulation of peripheral tissues and generating...... the resultant pain signal. The differential equation models describe the average firing rates of excitatory and inhibitory interneuron populations, as well as the wide dynamic range (WDR) neurons whose output correlates with the pain signal. The temporal profile of inputs on the different afferent nerve fibers...

  10. Do intensity ratings and skin conductance responses reliably discriminate between different stimulus intensities in experimentally induced pain?

    Science.gov (United States)

    Breimhorst, Markus; Sandrock, Stephan; Fechir, Marcel; Hausenblas, Nadine; Geber, Christian; Birklein, Frank

    2011-01-01

    The present study addresses the question whether pain-intensity ratings and skin conductance responses (SCRs) are able to detect different intensities of phasic painful stimuli and to determine the reliability of this discrimination. For this purpose, 42 healthy participants of both genders were assigned to either electrical, mechanical, or laser heat-pain stimulation (each n = 14). A whole range of single brief painful stimuli were delivered on the right volar forearm of the dominant hand in a randomized order. Pain-intensity ratings and SCRs were analyzed. Using generalizability theory, individual and gender differences were the main contributors to the variability of both intensity ratings and SCRs. Most importantly, we showed that pain-intensity ratings are a reliable measure for the discrimination of different pain stimulus intensities in the applied modalities. The reliability of SCR was adequate when mechanical and heat stimuli were tested but failed for the discrimination of electrical stimuli. Further studies are needed to reveal the reason for this lack of accuracy for SCRs when applying electrical pain stimuli. Our study could help researchers to better understand the relationship between pain and activation of the sympathetic nervous system. Pain researchers are furthermore encouraged to consider individual and gender differences when measuring pain intensity and the concomitant SCRs in experimental settings. Copyright © 2011 American Pain Society. Published by Elsevier Inc. All rights reserved.

  11. Pediatric Fear-Avoidance Model of Chronic Pain: Foundation, Application and Future Directions

    Directory of Open Access Journals (Sweden)

    Gordon JG Asmundson

    2012-01-01

    Full Text Available The fear-avoidance model of chronic musculoskeletal pain has become an increasingly popular conceptualization of the processes and mechanisms through which acute pain can become chronic. Despite rapidly growing interest and research regarding the influence of fear-avoidance constructs on pain-related disability in children and adolescents, there have been no amendments to the model to account for unique aspects of pediatric chronic pain. A comprehensive understanding of the role of fear-avoidance in pediatric chronic pain necessitates understanding of both child/adolescent and parent factors implicated in its development and maintenance. The primary purpose of the present article is to propose an empirically-based pediatric fear-avoidance model of chronic pain that accounts for both child/adolescent and parent factors as well as their potential interactive effects. To accomplish this goal, the present article will define important fear-avoidance constructs, provide a summary of the general fear-avoidance model and review the growing empirical literature regarding the role of fear-avoidance constructs in pediatric chronic pain. Assessment and treatment options for children with chronic pain will also be described in the context of the proposed pediatric fear-avoidance model of chronic pain. Finally, avenues for future investigation will be proposed.

  12. Reliability of four experimental mechanical pain tests in children

    DEFF Research Database (Denmark)

    Søe, Ann-Britt Langager; Thomsen, Lise L; Tornoe, Birte

    2013-01-01

    In order to study pain in children, it is necessary to determine whether pain measurement tools used in adults are reliable measurements in children. The aim of this study was to explore the intrasession reliability of pressure pain thresholds (PPT) in healthy children. Furthermore, the aim was a...... was also to study the intersession reliability of the following four tests: (1) Total Tenderness Score; (2) PPT; (3) Visual Analog Scale score at suprapressure pain threshold; and (4) area under the curve (stimulus-response functions for pressure versus pain).......In order to study pain in children, it is necessary to determine whether pain measurement tools used in adults are reliable measurements in children. The aim of this study was to explore the intrasession reliability of pressure pain thresholds (PPT) in healthy children. Furthermore, the aim...

  13. Pregabalin reduces acute inflammatory and persistent pain associated with nerve injury and cancer in rat models of orofacial pain.

    Science.gov (United States)

    Hummig, Wagner; Kopruszinski, Caroline Machado; Chichorro, Juliana Geremias

    2014-01-01

    To assess the analgesic effect of pregabalin in orofacial models of acute inflammatory pain and of persistent pain associated with nerve injury and cancer, and so determine its effectiveness in controlling orofacial pains having different underlying mechanisms. Orofacial capsaicin and formalin tests were employed in male Wistar rats to assess the influence of pregabalin (or vehicle) pretreatment in acute pain models, and the results from these experiments were analyzed by one-way analysis of variance (ANOVA) followed by Newman Keuls post-hoc test. Pregabalin (or vehicle) treatment was also tested on the facial heat hyperalgesia that was evaluated in rats receiving injection of the inflammatory irritant carrageenan into the upper lip, as well as after constriction of the infraorbital nerve (a model of trigeminal neuropathic pain), or after inoculation of tumor cells into the facial vibrissal pad; two-way repeated measures ANOVA followed by Newman-Keuls post-hoc test was used to analyze data from these experiments. Facial grooming induced by capsaicin was abolished by pretreatment with pregabalin at 10 and 30 mg/kg. However, pregabalin failed to modify the first phase of the formalin response, but reduced the second phase at both doses (10 and 30 mg/kg). In addition, treatment of rats with pregabalin reduced the heat hyperalgesia induced by carrageenan, as well as by nerve injury and facial cancer. Pregabalin produced a marked antinociceptive effect in rat models of facial inflammatory pain as well as in facial neuropathic and cancer pain models, suggesting that it may represent an important agent for the clinical control of orofacial pain.

  14. An improved model of heat-induced hyperalgesia--repetitive phasic heat pain causing primary hyperalgesia to heat and secondary hyperalgesia to pinprick and light touch.

    Science.gov (United States)

    Jürgens, Tim P; Sawatzki, Alexander; Henrich, Florian; Magerl, Walter; May, Arne

    2014-01-01

    This study tested a modified experimental model of heat-induced hyperalgesia, which improves the efficacy to induce primary and secondary hyperalgesia and the efficacy-to-safety ratio reducing the risk of tissue damage seen in other heat pain models. Quantitative sensory testing was done in eighteen healthy volunteers before and after repetitive heat pain stimuli (60 stimuli of 48°C for 6 s) to assess the impact of repetitive heat on somatosensory function in conditioned skin (primary hyperalgesia area) and in adjacent skin (secondary hyperalgesia area) as compared to an unconditioned mirror image control site. Additionally, areas of flare and secondary hyperalgesia were mapped, and time course of hyperalgesia determined. After repetitive heat pain conditioning we found significant primary hyperalgesia to heat, and primary and secondary hyperalgesia to pinprick and to light touch (dynamic mechanical allodynia). Acetaminophen (800 mg) reduced pain to heat or pinpricks only marginally by 11% and 8%, respectively (n.s.), and had no effect on heat hyperalgesia. In contrast, the areas of flare (-31%) and in particular of secondary hyperalgesia (-59%) as well as the magnitude of hyperalgesia (-59%) were significantly reduced (all pheat pain induces significant peripheral sensitization (primary hyperalgesia to heat) and central sensitization (punctate hyperalgesia and dynamic mechanical allodynia). These findings are relevant to further studies using this model of experimental heat pain as it combines pronounced peripheral and central sensitization, which makes a convenient model for combined pharmacological testing of analgesia and anti-hyperalgesia mechanisms related to thermal and mechanical input.

  15. An Improved Model of Heat-Induced Hyperalgesia—Repetitive Phasic Heat Pain Causing Primary Hyperalgesia to Heat and Secondary Hyperalgesia to Pinprick and Light Touch

    Science.gov (United States)

    Henrich, Florian; Magerl, Walter; May, Arne

    2014-01-01

    This study tested a modified experimental model of heat-induced hyperalgesia, which improves the efficacy to induce primary and secondary hyperalgesia and the efficacy-to-safety ratio reducing the risk of tissue damage seen in other heat pain models. Quantitative sensory testing was done in eighteen healthy volunteers before and after repetitive heat pain stimuli (60 stimuli of 48°C for 6 s) to assess the impact of repetitive heat on somatosensory function in conditioned skin (primary hyperalgesia area) and in adjacent skin (secondary hyperalgesia area) as compared to an unconditioned mirror image control site. Additionally, areas of flare and secondary hyperalgesia were mapped, and time course of hyperalgesia determined. After repetitive heat pain conditioning we found significant primary hyperalgesia to heat, and primary and secondary hyperalgesia to pinprick and to light touch (dynamic mechanical allodynia). Acetaminophen (800 mg) reduced pain to heat or pinpricks only marginally by 11% and 8%, respectively (n.s.), and had no effect on heat hyperalgesia. In contrast, the areas of flare (−31%) and in particular of secondary hyperalgesia (−59%) as well as the magnitude of hyperalgesia (−59%) were significantly reduced (all pheat pain induces significant peripheral sensitization (primary hyperalgesia to heat) and central sensitization (punctate hyperalgesia and dynamic mechanical allodynia). These findings are relevant to further studies using this model of experimental heat pain as it combines pronounced peripheral and central sensitization, which makes a convenient model for combined pharmacological testing of analgesia and anti-hyperalgesia mechanisms related to thermal and mechanical input. PMID:24911787

  16. Depression and Pain in Asian and White Americans With Knee Osteoarthritis.

    Science.gov (United States)

    Ahn, Hyochol; Weaver, Michael; Lyon, Debra; Choi, Eunyoung; Fillingim, Roger B

    2017-10-01

    Few studies have examined the underlying psychosocial mechanisms of pain in Asian Americans. Using the biopsychosocial model, we sought to determine whether variations in depression contribute to racial group differences in symptomatic knee osteoarthritis pain between Asian Americans and non-Hispanic white Americans. The sample consisted of 100 participants, including 50 Asian Americans (28 Korean Americans, 9 Chinese Americans, 7 Japanese Americans, 5 Filipino Americans, and 1 Indian American) and 50 age- and sex-matched non-Hispanic white Americans with symptomatic knee osteoarthritis pain. The Centers for Epidemiologic Studies Depression Scale was used to assess symptoms of depression, and the Western Ontario and McMaster Universities Osteoarthritis Index and the Graded Chronic Pain Scale were used to measure clinical pain. In addition, quantitative sensory testing was used to measure experimental sensitivity to heat- and mechanically-induced pain. The results indicated that higher levels of depression in Asian Americans may contribute to greater clinical pain and experimental pain sensitivity. These findings add to the growing literature regarding ethnic and racial differences in pain and its associated psychological conditions, and additional research is warranted to strengthen these findings. This article shows the contribution of depression to clinical pain and experimental pain sensitivity in Asian Americans with knee osteoarthritis. Our results suggest that Asian Americans have higher levels of depressive symptoms and that depression plays a relevant role in greater clinical pain and experimental pain sensitivity in Asian Americans. Copyright © 2017 American Pain Society. Published by Elsevier Inc. All rights reserved.

  17. Toward the development of a motivational model of pain self-management.

    Science.gov (United States)

    Jensen, Mark P; Nielson, Warren R; Kerns, Robert D

    2003-11-01

    Adaptive management of chronic pain depends to a large degree on how patients choose to cope with pain and its impact. Consequently, patient motivation is an important factor in determining how well patients learn to manage pain. However, the role of patient motivation in altering coping behavior and maintaining those changes is seldom discussed, and theoretically based research on motivation for pain treatment is lacking. This article reviews theories that have a direct application to understanding motivational issues in pain coping and presents a preliminary motivational model of pain self-management. The implications of this model for enhancing engagement in and adherence to chronic pain treatment programs are then discussed. The article ends with a call for research to better understand motivation as it applies to chronic pain self-management. In particular, there is a need to determine whether (and which) motivation enhancement interventions increase active participation in self-management treatment programs for chronic pain.

  18. Effect of experimental stress in 2 different pain conditions affecting the facial muscles.

    Science.gov (United States)

    Woda, Alain; L'heveder, Gildas; Ouchchane, Lemlih; Bodéré, Céline

    2013-05-01

    Chronic facial muscle pain is a common feature in both fibromyalgia (FM) and myofascial (MF) pain conditions. In this controlled study, a possible difference in the mode of deregulation of the physiological response to a stressing stimulus was explored by applying an acute mental stress to FM and MF patients and to controls. The effects of the stress test were observed on pain, sympathetic variables, and both tonic and reflex electromyographic activities of masseteric and temporal muscles. The statistical analyses were performed through a generalized linear model including mixed effects. Painful reaction to the stressor was stronger (P < .001) and longer (P = .011) in FM than in MF independently of a higher pain level at baseline. The stress-induced autonomic changes only seen in FM patients did not reach significance. The electromyographic responses to the stress test were strongest for controls and weakest for FM. The stress test had no effect on reflex activity (area under the curve [AUC]) or latency, although AUC was high in FM and latencies were low in both pain groups. It is suggested that FM is characterized by a lower ability to adapt to acute stress than MF. This study showed that an acute psychosocial stress triggered several changes in 2 pain conditions including an increase in pain of larger amplitude in FM than in MF pain. Similar stress-induced changes should be explored as possible mechanisms for differentiation between dysfunctional pain conditions. Copyright © 2013 American Pain Society. Published by Elsevier Inc. All rights reserved.

  19. Rat experimental model of myocardial ischemia/reperfusion injury: an ethical approach to set up the analgesic management of acute post-surgical pain.

    Directory of Open Access Journals (Sweden)

    Maria Chiara Ciuffreda

    Full Text Available RATIONALE: During the past 30 years, myocardial ischemia/reperfusion injury in rodents became one of the most commonly used model in cardiovascular research. Appropriate pain-prevention appears critical since it may influence the outcome and the results obtained with this model. However, there are no proper guidelines for pain management in rats undergoing thoracic surgery. Accordingly, we evaluated three analgesic regimens in cardiac ischemia/reperfusion injury. This study was strongly focused on 3R's ethic principles, in particular the principle of Reduction. METHODS: Rats undergoing surgery were treated with pre-surgical tramadol (45 mg/kg intra-peritoneal, or carprofen (5 mg/kg sub-cutaneous, or with pre-surgical administration of carprofen followed by 2 post-surgery tramadol injections (multi-modal group. We assessed behavioral signs of pain and made a subjective evaluation of stress and suffering one and two hours after surgery. RESULTS: Multi-modal treatment significantly reduced the number of signs of pain compared to carprofen alone at both the first hour (61±42 vs 123±47; p<0.05 and the second hour (43±21 vs 74±24; p<0.05 post-surgery. Tramadol alone appeared as effective as multi-modal treatment during the first hour, but signs of pain significantly increased one hour later (from 66±72 to 151±86, p<0.05. Carprofen alone was more effective at the second hour post-surgery when signs of pain reduced to 74±24 from 113±40 in the first hour (p<0.05. Stress behaviors during the second hour were observed in only 20% of rats in the multimodal group compared to 75% and 86% in the carprofen and tramadol groups, respectively (p<0.05. CONCLUSIONS: Multi-modal treatment with carprofen and tramadol was more effective in preventing pain during the second hour after surgery compared with both tramadol or carprofen. Our results suggest that the combination of carprofen and tramadol represent the best therapy to prevent animal pain after

  20. Length of perineal pain relief after ice pack application: A quasi-experimental study.

    Science.gov (United States)

    de Souza Bosco Paiva, Caroline; Junqueira Vasconcellos de Oliveira, Sonia Maria; Amorim Francisco, Adriana; da Silva, Renata Luana; de Paula Batista Mendes, Edilaine; Steen, Mary

    2016-04-01

    Ice pack is effective for alleviating postpartum perineal pain in primiparous women while multiparous women's levels of perineal pain appear to be poorly explored. Ice pack is a low-cost non-invasive localised treatment that can be used with no impact on breastfeeding. However, how long perineal analgesia persists after applying an ice pack is still unknown. To evaluate if perineal analgesia is maintained up to 2h after applying an ice pack to the perineum for 20min. A quasi-experimental study, using a pre and post-test design, was undertaken with a sample size of 50 multiparous women in Brazil. Data was collected by structured interview. The intervention involved a single application of an ice pack applied for 20min to the perineal area of women who reported perineal pain ≥3 by use of a numeric rating scale (0-10), with intact perineum, 1st or 2nd degree lacerations or episiotomy, between 6 and 24h after spontaneous vaginal birth. Perineal pain was evaluated at three points of time: before, immediately after and 2h after applying an ice pack. Immediately after applying an ice pack to the perineal area, there was a significant reduction in the severity of perineal pain reported (5.4 vs. 1.0, p<0.0005), which continued for 1h 35min up to 2h after the local application. Ice pack application for 20min is effective for alleviating postpartum perineal pain and continues to be effective between 1h 35min for up to 2h. Copyright © 2015 Australian College of Midwives. Published by Elsevier Ltd. All rights reserved.

  1. Complex muscular adaptation to perturbations after induction of experimental low back pain in healthy participants

    DEFF Research Database (Denmark)

    Larsen, Lars Henrik; Hirata, Rogerio Pessoto; Graven-Nielsen, Thomas

    2014-01-01

    Background and aims Spine stability is affected in low back (LB) pain and potentially by muscle fatigue and soreness. This study assessed motor control responses to unexpected surface perturbations during stance during experimental LB muscle pain combined with fatigue and muscle soreness. Methods...... Nineteen healthy participants were examined day 1-3 before and after bilateral injections of hypertonic saline into m. longissimus. Pain intensity was scored on a visual analogue scale (VAS). Day 2 included injections during post-exercise LB muscle fatigue and day 3 during delayed onset back muscle...... soreness (DOMS). Twenty perturbations were conducted randomly with tilts in sagittal and frontal plane or displacements in the frontal plane. Bilateral electromyography (EMG) was recorded from 12 trunk muscles. The root-mean-square (RMS-EMG) was extracted. Changes (DeltaRMS) and absolute changes (Delta...

  2. Effects of a Pain Catastrophizing Induction on Sensory Testing in Women with Chronic Low Back Pain: A Pilot Study

    OpenAIRE

    Taub, Chloe J.; Sturgeon, John A.; Johnson, Kevin A.; Mackey, Sean C.; Darnall, Beth D.

    2017-01-01

    Pain catastrophizing, a pattern of negative cognitive-emotional responses to actual or anticipated pain, maintains chronic pain and undermines response to treatments. Currently, precisely how pain catastrophizing influences pain processing is not well understood. In experimental settings, pain catastrophizing has been associated with amplified pain processing. This study sought to clarify pain processing mechanisms via experimental induction of pain catastrophizing. Forty women with chronic l...

  3. Spinal cord stimulation of dorsal columns in a rat model of neuropathic pain: evidence for a segmental spinal mechanism of pain relief.

    Science.gov (United States)

    Smits, H; van Kleef, M; Joosten, E A

    2012-01-01

    Although spinal cord stimulation (SCS) of the dorsal columns is an established method for treating chronic neuropathic pain, patients still suffer from a substantial level of pain. From a clinical perspective it is known that the location of the SCS is of pivotal importance, thereby suggesting a segmental spinal mode of action. However, experimental studies suggest that SCS acts also through the modulation of supraspinal mechanisms, which might suggest that the location is unimportant. Here we investigated the effect of the rostrocaudal location of SCS stimulation and the effectiveness of pain relief in a rat model of chronic neuropathic pain. Adult male rats (n=45) were submitted to a partial ligation of the sciatic nerve. The majority of animals developed tactile hypersensitivity in the nerve lesioned paw. All allodynic rats were submitted to SCS (n=33) for 30 minutes (f=50 Hz; pulse width 0.2 ms). In one group (n=16) the electrodes were located at the level where the injured sciatic nerve afferents enter the spinal cord (T13), and in a second group (n=17) the electrodes were positioned at more rostral levels (T11) as verified by X-ray. A repositioning experiment of electrodes from T12 to T13 was performed in 2 animals. Our data demonstrate that SCS of the dorsal columns at the level where the injured fibers enter the spinal cord dorsal horn result in a much better pain-relieving effect than SCS at more rostral levels. From this we conclude that SCS in treatment of neuropathic pain acts through a segmental spinal site of action. Copyright © 2011 International Association for the Study of Pain. Published by Elsevier B.V. All rights reserved.

  4. When pain meets … pain-related choice behavior and pain perception in different goal conflict situations.

    Science.gov (United States)

    Schrooten, Martien G S; Wiech, Katja; Vlaeyen, Johan W S

    2014-11-01

    Individuals in pain often face the choice between avoiding pain and pursuing other equally valued goals. However, little is known about pain-related choice behavior and pain perception in goal conflict situations. Seventy-eight healthy volunteers performed a computerized task requiring repeated choices between incompatible options, differing in their effect on probability to receive painful stimulation and money. Depending on group assignment, participants chose between increased pain probability versus decreased money probability (avoidance-avoidance conflict situation); decreased pain probability versus increased money probability (approach-approach conflict situation); or decrease versus increase in both probabilities (double approach/avoidance conflict situation). During the choice task, participants rated painfulness, unpleasantness, threat, and fearfulness associated with the painful stimulation and how they felt. Longer choice latency and more choice switching were associated with higher retrospective ratings of conflict and of decision difficulty, and more equal importance placed on pain avoidance and earning money. Groups did not differ in choice behavior, pain stimulus ratings, or affect. Across groups, longer choice latencies were nonsignificantly associated with higher pain, unpleasantness, threat, and fearfulness. In the avoidance-avoidance group, more choice switching was associated with higher pain-related threat and fearfulness, and with more negative affect. These results of this study suggest that associations between choice behaviors, pain perception, and affect depend on conflict situation. We present a first experimental demonstration of the relationship between pain-related choice behaviors, pain, and affect in different goal conflict situations. This experimental approach allows us to examine these relationships in a controlled fashion. Better understanding of pain-related goal conflicts and their resolution may lead to more effective pain

  5. Impaired behavioural pain responses in hph-1 mice with inherited deficiency in GTP cyclohydrolase 1 in models of inflammatory pain

    Science.gov (United States)

    2013-01-01

    Background GTP cyclohydrolase 1 (GTP-CH1), the rate-limiting enzyme in the synthesis of tetrahydrobiopterin (BH4), encoded by the GCH1 gene, has been implicated in the development and maintenance of inflammatory pain in rats. In humans, homozygous carriers of a “pain-protective” (PP) haplotype of the GCH1 gene have been identified exhibiting lower pain sensitivity, but only following pain sensitisation. Ex vivo, the PP GCH1 haplotype is associated with decreased induction of GCH1 after stimulation, whereas the baseline BH4 production is not affected. Contrary, loss of function mutations in the GCH1 gene results in decreased basal GCH1 expression, and is associated with DOPA-responsive dystonia (DRD). So far it is unknown if such mutations affect acute and inflammatory pain. Results In the current study, we examined the involvement of the GCH1 gene in pain models using the hyperphenylalaninemia 1 (hph-1) mouse, a genetic model for DRD, with only 10% basal GTP-CH1 activity compared to wild type mice. The study included assays for determination of acute nociception as well as models for pain after sensitisation. Pain behavioural analysis of the hph-1 mice showed reduced pain-like responses following intraplantar injection of CFA, formalin and capsaicin; whereas decreased basal level of GTP-CH1 activity had no influence in naïve hph-1 mice on acute mechanical and heat pain thresholds. Moreover, the hph-1 mice showed no signs of motor impairment or dystonia-like symptoms. Conclusions In this study, we demonstrate novel evidence that genetic mutations in the GCH1 gene modulate pain-like hypersensitivity. Together, the present data suggest that BH4 is not important for basal heat and mechanical pain, but they support the hypothesis that BH4 plays a role in inflammation-induced hypersensitivity. Our studies suggest that the BH4 pathway could be a therapeutic target for the treatment of inflammatory pain conditions. Moreover, the hph-1 mice provide a valid model to

  6. Body awareness and responses to experimentally Induced pain

    Directory of Open Access Journals (Sweden)

    M. Minev

    2017-09-01

    Full Text Available PURPOSE. The aim of this study is to discuss personal and demographic factors that influence the relationship between physical activity and awareness of one's own body, as well as the pain response (threshold and tolerance of pain, situational anxiety and personality. In the study 38 healthy individual- volunteers, students in Trakia University - Stara Zagora were selected. All participants were divided into two groups: actively involved in individual or team sport (n = 19 and healthy normaly active subjects (non-athletes, n = 19. The age of the study participants ranged between 18 and 39 years, while the gender breakdown was as follows: men - 22 women – 16. Methods: Psychological Questionnaires: Body Awareness Questionnaire that asks subjects to rate, on a 4 point scale, the degree to which they were currently experiencing symptoms of sympathetic arousal, State Trait Anger Scale, and State Trait Anxiety Scale. Objective methods (cold pressure test are used only to determine the pain sensation and pain tolerance thresholds. The results of investigation support significant differences between athletes and non-athletes in pain thershold, body awareness and anxiety. The study conclusions discuss body awareness as an increasing factor for pain resistance in athletes and as an integral part of the learning process among them.

  7. Altering gender role expectations: effects on pain tolerance, pain threshold, and pain ratings.

    Science.gov (United States)

    Robinson, Michael E; Gagnon, Christine M; Riley, Joseph L; Price, Donald D

    2003-06-01

    The literature demonstrating sex differences in pain is sizable. Most explanations for these differences have focused on biologic mechanisms, and only a few studies have examined social learning. The purpose of this study was to examine the contribution of gender-role stereotypes to sex differences in pain. This study used experimental manipulation of gender-role expectations for men and women. One hundred twenty students participated in the cold pressor task. Before the pain task, participants were given 1 of 3 instructional sets: no expectation, 30-second performance expectation, or a 90-second performance expectation. Pain ratings, threshold, and tolerance were recorded. Significant sex differences in the "no expectation" condition for pain tolerance (t = 2.32, df = 38, P differ in their pain tolerance, pain threshold, or pain ratings. This is the first empirical study to show that manipulation of expectations alters sex differences in laboratory pain.

  8. Managing painful chronic wounds: the Wound Pain Management Model

    DEFF Research Database (Denmark)

    Price, Patricia; Fogh, Karsten; Glynn, Chris

    2007-01-01

    of the pain experience: location, duration, intensity, quality, onset and impact on activities of daily living. Holistic management must be based on a safe and effective mix of psychosocial approaches together with local and systemic pain management. It is no longer acceptable to ignore or inadequately...... to the wound should be handled as one of the main priorities in chronic wound management together with addressing the cause. Management of pain in chronic wounds depends on proper assessment, reporting and documenting patient experiences of pain. Assessment should be based on six critical dimensions...... document persistent wound pain and not to develop a treatment and monitoring strategy to improve the lives of persons with chronic wounds. Unless wound pain is optimally managed, patient suffering and costs to health care systems will increase. Udgivelsesdato: 2007-Apr...

  9. Jaw-motor effects of experimental jaw-muscle pain and stress in patients with deep bite and matched control subjects

    DEFF Research Database (Denmark)

    Sonnesen, Liselotte; Svensson, Peter

    2013-01-01

    clenching, during evoked pain and stress between deep bite patients and controls was investigated. DESIGN: In 30 deep bite patients and in 30 sex-/age-matched controls with neutral occlusion EMG activity was recorded bilaterally from masseter and anterior temporalis muscles before and during evoked pain......OBJECTIVE: The effect of experimental jaw-muscle pain and stress on masticatory muscle activity in TMD-patients has been discussed. Furthermore, associations between TMD and deep bite patients have been studied. Accordingly in the present study, comparison of EMG responses at rest, maximal...... and before and during a stress task. Evoked pain was induced by injections of glutamate into the masseter (local pain) and brachioradialis (remote pain) muscles and resting EMG activity was recorded before and after 1, 2, 3, 4, 5 and 10min. A precision task was used to simulate a stressful condition and EMG...

  10. Effect of painful and non-painful sensorimotor manipulations on subjective body midline

    Directory of Open Access Journals (Sweden)

    Jason eBouffard

    2013-03-01

    Full Text Available Patients with chronic pain often show disturbances in their body perception. Understanding the exact role played by pain is however complex, as confounding factors can contribute to the observed deficits in these clinical populations. To address this question, acute experimental pain was used to test the effect of lateralized pain on body perception in healthy subjects. Subjects were asked to indicate the position of their body midline (subjective body midline, SBM by stopping a moving luminescent dot projected on a screen placed in front of them, in a completely dark environment. The effect of other nonpainful sensorimotor manipulations was also tested to assess the potential unspecific attentional effects of stimulating one side of the body. SBM judgment was made in seventeen volunteers under control and three experimental conditions: 1 painful (heat stimulation; 2 nonpainful vibrotactile stimulation; and 3 muscle contraction. The effects of the stimulated side and the type of trial (control vs. experimental condition, were tested separately for each condition with a 2 x 2 repeated measures ANOVA. The analyses revealed a significant interaction in both pain (p = 0.05 and vibration conditions (p = 0.04. Post-hoc tests showed opposite effects of pain and vibration. Pain applied on the right arm deviated the SBM toward the right (stimulated side (p = 0.03 while vibration applied on the left arm deviated the SBM toward the right (not stimulated side (p = 0.01. These opposite patterns suggest that the shift in SBM is likely to be specifically linked to the stimulation modality. It is concluded that acute experimental pain can induce an SBM shift toward the stimulated side, which might be functionally beneficial to protect the painful area of the body. Interestingly, it appears to be easier to bias SBM toward the right side, regardless of the modality and of the stimulated side.

  11. Analgesic effect of clobazam in chronic low-back pain but not in experimentally induced pain.

    Science.gov (United States)

    Schliessbach, J; Vuilleumier, P H; Siegenthaler, A; Bütikofer, L; Limacher, A; Juni, P; Zeilhofer, H U; Arendt-Nielsen, L; Curatolo, M

    2017-09-01

    Chronic pain is frequently associated with hypersensitivity of the nervous system, and drugs that increase central inhibition are therefore a potentially effective treatment. Benzodiazepines are potent modulators of GABAergic neurotransmission and are known to exert antihyperalgesic effects in rodents, but translation into patients are lacking. This study investigates the effect of the benzodiazepine clobazam in chronic low-back pain in humans. The aim of this study is to explore the effect of GABA modulation on chronic low-back pain and on quantitative sensory tests. In this double-blind cross-over study, 49 patients with chronic low-back pain received a single oral dose of clobazam 20 mg or active placebo tolterodine 1 mg. Pain intensity on the 0-10 numeric rating scale and quantitative sensory tests were assessed during 2 h after drug intake. Pain intensity in the supine position was significantly reduced by clobazam compared to active placebo (60 min: 2.9 vs. 3.5, p = 0.008; 90 min: 2.7 vs. 3.3, p = 0.024; 120 min: 2.4 vs. 3.1, p = 0.005). Pain intensity in the sitting position was not significantly different between groups. No effects on quantitative sensory tests were observed. This study suggests that clobazam has an analgesic effect in patients with chronic low-back pain. Muscle relaxation or sedation may have contributed to the effect. Development of substances devoid of these side effects would offer the potential to further investigate the antihyperalgesic action of GABAergic compounds. Modulation of GABAergic pain-inhibitory pathways may be a potential future therapeutic target. © 2017 European Pain Federation - EFIC®.

  12. Attenuation of Experimental Pain by Vibro-Tactile Stimulation in Patients with Chronic Local or Widespread Musculoskeletal Pain

    OpenAIRE

    Staud, Roland; Robinson, Michael E.; Goldman, Casey T.; Price, Donald D.

    2011-01-01

    Patients with chronic pain syndromes, like fibromyalgia (FM) complain of widespread pain and tenderness, as well as non-refreshing sleep, cognitive dysfunction, and negative mood. Several lines of evidence implicate abnormalities of central pain processing as contributors for chronic pain, including dysfunctional descending pain inhibition. One form of endogenous pain inhibition, diffuse noxious inhibitory controls (DNIC), has been found to be abnormal in some chronic pain patients and eviden...

  13. The Effect of Intrathecal Administration of Muscimol on Modulation of Neuropathic Pain Symptoms Resulting from Spinal Cord Injury; an Experimental Study

    Directory of Open Access Journals (Sweden)

    Marjan Hosseini

    2014-09-01

    Full Text Available Introduction: Neuropathic pain can be very difficult to treat and it is one of the important medical challenging about pain treatments. Muscimol as a new agonist of gamma-Aminobutyric acid receptor type A (GABAA have been introduced for pain management. Thus, the present study was performed to evaluate the pain alleviating effect of intrathecal injection of different doses of muscimol as GABAA receptor agonist in spinal cord injury (SCI model of neuropathic pain. Methods: In the present experimental study male Wistar rats were treated by muscimol 0.01, 0.1 or 1 µg/10ul, intrathecally (i.t. three weeks after induction of spinal cord injury using compression injury model. Neuropathic pain symptoms were assessed at before treatment, 15 minutes, one hour and three hours after muscimol administration. The time of peak effect and optimum dosage was assessed by repeated measures analysis of variance and analysis of covariance, respectively. Results: Muscimol with the dose of 0.01 µg in 15 minutes caused to improve the thermal hyperalgesia (df: 24, 5; F= 6.6; p<0.001, mechanical hyperalgesia (df: 24, 5; F= 7.8; p<0.001, cold allodynia (df: 24, 5; F= 6.96; p<0.001, and mechanical allodynia (df: 24, 5; F= 15.7; p<0.001. The effect of doses of 0.1 µg and 1 µg were also significant. In addition, the efficacy of different doses of muscimol didn't have difference on thermal hyperalgesia (df: 24, 5; F= 1.52; p= 0.24, mechanical hyperalgesia (df: 24, 5; F= 0.3; p= -0.75, cold allodynia (df: 24, 5; F= 0.8; p= -0.56, and mechanical allodynia (df: 24, 5; F= 1.75; p= 0.86. Conclusion: The finding of the present study revealed that using muscimol with doses of 0.01µg, 0.1µg, and 1 µg reduces the symptoms of neuropathic pain. Also the effect of GABAA agonist is short term and its effectiveness gradually decreases by time.

  14. Pain Relief in Nonhuman Primate Models of Arthritis.

    Science.gov (United States)

    Vierboom, Michel P M; Breedveld, Elia; Keehnen, Merei; Klomp, Rianne; Bakker, Jaco

    2017-01-01

    Animal models of rheumatoid arthritis are important in the elucidation of etiopathogenic mechanisms of the disease and for the development of promising new therapies. Species specificity of new biological compounds and their mode of action preclude safety and efficacy testing in rodent models of disease. Nonhuman primates (NHP) can fill this niche and provide the only relevant model. Over the last two decades models of collagen-induced arthritis (CIA) were developed in the rhesus monkey and the common marmoset. However, NHP are higher-order animals and complex sentient beings. So especially in models where pain is an intricate part of the disease, analgesia needs to be addressed because of ethical considerations. In our model, a morphine-based pain relief was used that does not interfere with the normal development of disease allowing us to evaluate important mechanistic aspects of the arthritis.

  15. Are Pain-Related Fears Mediators for Reducing Disability and Pain in Patients with Complex Regional Pain Syndrome Type 1? An Explorative Analysis on Pain Exposure Physical Therapy

    Science.gov (United States)

    Barnhoorn, Karlijn J.; Staal, J. Bart; van Dongen, Robert T. M.; Frölke, Jan Paul M.; Klomp, Frank P.; van de Meent, Henk; Samwel, Han; Nijhuis-van der Sanden, Maria W. G.

    2015-01-01

    Objective To investigate whether pain-related fears are mediators for reducing disability and pain in patients with Complex Regional Pain Syndrome type 1 when treating with Pain Exposure Physical Therapy. Design An explorative secondary analysis of a randomised controlled trial. Participants Fifty-six patients with Complex Regional Pain Syndrome type 1. Interventions The experimental group received Pain Exposure Physical Therapy in a maximum of five treatment sessions; the control group received conventional treatment following the Dutch multidisciplinary guideline. Outcome measures Levels of disability, pain, and pain-related fears (fear-avoidance beliefs, pain catastrophizing, and kinesiophobia) were measured at baseline and after 3, 6, and 9 months follow-up. Results The experimental group had a significantly larger decrease in disability of 7.77 points (95% CI 1.09 to 14.45) and in pain of 1.83 points (95% CI 0.44 to 3.23) over nine months than the control group. The potential mediators pain-related fears decreased significantly in both groups, but there were no significant differences between groups, which indicated that there was no mediation. Conclusion The reduction of pain-related fears was comparable in both groups. We found no indication that pain-related fears mediate the larger reduction of disability and pain in patients with Complex Regional Pain Syndrome type 1 treated with Pain Exposure Physical Therapy compared to conventional treatment. Trial registration International Clinical Trials Registry NCT00817128 PMID:25919011

  16. Thermal and pressure pain sensitivity in patients with unilateral shoulder pain: comparison of involved and uninvolved sides.

    Science.gov (United States)

    Coronado, Rogelio A; Kindler, Lindsay L; Valencia, Carolina; George, Steven Z

    2011-03-01

    Cross-sectional. In the examination of patients with unilateral shoulder pain, pain provocation testing to compare the involved and uninvolved sides has been considered useful. However, side-to-side comparisons of experimental pain sensitivity in patients with unilateral shoulder pain are not widely reported in the literature. To compare experimental pain sensitivity between the involved and uninvolved sides in patients with unilateral shoulder pain. In consecutive patients seeking operative treatment for shoulder pain, sensitivity measures of bilateral pressure pain threshold at the shoulder and forearm, and thermal pain threshold, tolerance, and temporal summation at the forearm, were examined. Pressure sensitivity was tested with a Fischer pressure algometer, and thermal sensitivity with a computer-controlled Medoc neurosensory analyzer. The involved and uninvolved sides were compared with an analysis of variance. Influence of sex and location of testing were considered as covariates in the analysis. Fifty-nine consecutively recruited participants completed experimental pain sensitivity testing. Participants reported significantly lower pressure pain thresholds in the involved side compared to the uninvolved side (F1,56 = 4.96, P = .030). In addition, female compared to male participants demonstrated lower pressure pain thresholds in the bilateral shoulder regions (F1,56 = 10.84, P = .002). There was no difference in thermal pain sensitivity between sides. Average clinical pain intensity was negatively correlated with pressure pain threshold at the involved local site (r = -0.284, P = .029), indicating an influence of clinical pain intensity on local pressure pain. The results of this study provide evidence for higher experimental pressure pain sensitivity in the involved side of patients with unilateral shoulder pain and no difference between sides for thermal pain sensitivity. Females demonstrated higher pain sensitivity than males to pressure stimuli at the

  17. Bridging the gap between mind and body: a biobehavioral model of the effects of guided imagery on pain, pain disability, and depression.

    Science.gov (United States)

    Lewandowski, Wendy; Jacobson, Ann

    2013-12-01

    Chronic noncancer pain (CNCP) is a common and complex disorder associated with declines in physical health and functional status, emotional well-being, and quality of life. To best address the complexity of this condition, research and clinical practice for CNCP should be guided by a framework incorporating both biologic and psychologic factors. This article presents a biobehavioral model of chronic pain that hypothesizes mechanisms related to the effectiveness of a complementary therapy, guided imagery (GI), for this population. Using the research-to-model/theory strategy, we mapped findings from published reports of interdisciplinary research into physiologic and psychologic aspects of the nature and mechanisms of pain, as well as the use of GI for pain, to build the model of GI's effects on pain, pain disability, and depression. In the model, these outcomes of GI for persons experiencing CNCP are mediated by psychologic (pain self-efficacy and pain beliefs) and physiologic (immune-mediated analgesia and sickness response) variables. A biobehavioral approach to nursing phenomena will advance understanding of health and health-related issues and has the potential to improve outcomes through delineation of mechanisms underlying relationships between psychologic and biologic factors. Increased consumer use of complementary therapies to treat pain, the current cost-driven health care system, and the mandate for evidence-based practice support the need to validate the efficacy of such therapies. This empirically derived model provides a framework for practice and research for nurses and other health care providers to promote health, function, and well-being in persons with CNCP. Copyright © 2013 American Society for Pain Management Nursing. Published by Elsevier Inc. All rights reserved.

  18. Stress and visceral pain: from animal models to clinical therapies

    Science.gov (United States)

    Larauche, Muriel; Mulak, Agata; Taché, Yvette

    2011-01-01

    Epidemiological studies have implicated stress (psychosocial and physical) as a trigger of first onset or exacerbation of irritable bowel syndrome (IBS) symptoms of which visceral pain is an integrant landmark. A number of experimental acute or chronic exteroceptive or interoceptive stressors induce visceral hyperalgesia in rodents although recent evidence also points to stress-related visceral analgesia as established in the somatic pain field. Underlying mechanisms of stress-related visceral hypersensitivity may involve a combination of sensitization of primary afferents, central sensitization in response to input from the viscera and dysregulation of descending pathways that modulate spinal nociceptive transmission or analgesic response. Biochemical coding of stress involves the recruitment of corticotropin releasing factor (CRF) signaling pathways. Experimental studies established that activation of brain and peripheral CRF receptor subtype 1 plays a primary role in the development of stress-related delayed visceral hyperalgesia while subtype 2 activation induces analgesic response. In line with stress pathways playing a role in IBS, non-pharmacologic and pharmacologic treatment modalities aimed at reducing stress perception using a broad range of evidence-based mind-body interventions and centrally-targeted medications to reduce anxiety impact on brain patterns activated by visceral stimuli and dampen visceral pain. PMID:21575632

  19. Experimental Object-Oriented Modelling

    DEFF Research Database (Denmark)

    Hansen, Klaus Marius

    through, e.g., technical prototyping and active user involvement. We introduce and examine “experimental object-oriented modelling” as the intersection of these practices. The contributions of this thesis are expected to be within three perspectives on models and modelling in experimental system...... development: Grounding We develop an empirically based conceptualization of modelling and use of models in system development projects characterized by a high degree of uncertainty in requirements and point to implications for tools and techniques for modelling in such a setting. Techniques We introduce......This thesis examines object-oriented modelling in experimental system development. Object-oriented modelling aims at representing concepts and phenomena of a problem domain in terms of classes and objects. Experimental system development seeks active experimentation in a system development project...

  20. Characterization of a novel model of tonic heat pain stimulation in healthy volunteers

    DEFF Research Database (Denmark)

    Naert, A.L.; Kehlet, H.; Kupers, R.

    2008-01-01

    .2+/-0.4, females scoring higher than men (7.4+/-0.5 vs. 5.2+/-0.5; pstimulation period after which they stabilized. A strong interindividual variability was observed in the time profiles of the pain ratings over the course of the 7-min...... tonic heat pain stimulation and compared the responses on this test with other measures of pain. In 58 normal volunteers, we applied a 7-min lasting contact heat stimulation of 47 degrees C to the upper leg while participants constantly rated their pain. Average pain rating during the 7-min period was 6...... stimulation period. The model showed a good test-retest reproducibility. Tonic heat pain ratings only correlated moderately with the pain threshold while stronger correlations were observed with pain tolerance and ratings of suprathreshold phasic heat pain. We conclude that the tonic heat model is a suitable...

  1. Relationships between craniofacial pain and bruxism.

    Science.gov (United States)

    Svensson, P; Jadidi, F; Arima, T; Baad-Hansen, L; Sessle, B J

    2008-07-01

    A still commonly held view in the literature and clinical practice is that bruxism causes pain because of overloading of the musculoskeletal tissue and craniofacial pain, on the other hand, triggers more bruxism. Furthermore, it is often believed that there is a dose-response gradient so that more bruxism (intensity, duration) leads to more overloading and pain. Provided the existence of efficient techniques to treat bruxism, it would be straightforward in such a simple system to target bruxism as the cause of pain and hence treat the pain. Of course, human biological systems are much more complex and therefore, it is no surprise that the relationship between bruxism and pain is far from being simple or even linear. Indeed, there are unexpected relationships, which complicate the establishment of adequate explanatory models. Part of the reason is the complexity of the bruxism in itself, which presents significant challenges related to operationalized criteria and diagnostic tools and underlying pathophysiology issues, which have been dealt with in other reviews in this issue. However, another important reason is the multifaceted nature of craniofacial pain. This review will address our current understanding of classification issues, epidemiology and neurobiological mechanisms of craniofacial pain. Experimental models of bruxism may help to further the understanding of the relationship between craniofacial pain and bruxism in addition to insights from intervention studies. The review will enable clinicians to understand the reasons why simple cause-effect relationships between bruxism and craniofacial pain are inadequate and the current implications for management of craniofacial pain.

  2. Prediction of postoperative pain by preoperative pain response to heat stimulation in total knee arthroplasty

    DEFF Research Database (Denmark)

    Lunn, Troels H; Gaarn-Larsen, Lissi; Kehlet, Henrik

    2013-01-01

    It has been estimated that up to 54% of the variance in postoperative pain experience may be predicted with preoperative pain responses to experimental stimuli, with suprathreshold heat pain as the most consistent test modality. We aimed to explore if 2 heat test paradigms could predict postopera......It has been estimated that up to 54% of the variance in postoperative pain experience may be predicted with preoperative pain responses to experimental stimuli, with suprathreshold heat pain as the most consistent test modality. We aimed to explore if 2 heat test paradigms could predict...... and logistic regressions analyses were carried out including 8 potential preoperative explanatory variables (among these anxiety, depression, preoperative pain and pain catastrophizing) to assess pain response to preoperative heat pain stimulation as independent predictor for postoperative pain. 100 patients...... by the linear and logistic regression analyses, where only anxiety, preoperative pain and pain catastrophizing were significant explanatory variables (but with low R-Squares;0.05-0.08). Pain responses to 2 types of preoperative heat stimuli were not independent clinical relevant predictors for postoperative...

  3. Effects of Hemibridge with Ball and Balloon Exercise on Forced Expiratory Volume and Pain in Patients with Chronic Low Back Pain: An Experimental Study

    Directory of Open Access Journals (Sweden)

    Jorida Fernandes

    2017-08-01

    Full Text Available Background and objectives: Suboptimal breathing patterns and impairments of posture and trunk stability are often associated with musculoskeletal complaints such as low back pain. Respiration is also affected by poor neuromuscular control of core muscles. Immediate effects of hemibridge with ball and balloon exercise has been studied on chronic pain in athlete population. Objective: To evaluate the effects of hemibridge with ball and balloon exercise on pain, forced expiratory volume and functional abilities in patients with chronic low back pain using Visual Analogue Scale (VAS, Forced Expiratory Volume (FEV and Modified Oswestry Disability Questionnaire (MODQ. Methods: The present experimental study was conducted among 30 participants between the age of 21 to 55 years with chronic non-specific LBP. The participants were given a hemibridge with ball and balloon exercise. Pre-interventional and 3rd day Post-interventional outcome measurements were taken using VAS, FEV1 and FEV6 and MODQ. Results: The difference between pre-and post of VAS was statistically highly significant (p=0.0001. The p value of FEV6 and MODQ by paired t test was statistically significant with p value of 0.02 and 0.0007 respectively. Conclusion: The study concludes that there is an immediate effect of hemibridge with ball and balloon exercise on pain, FEV6 and functional ability in patients with chronic LBP.

  4. Analgesic efficacy of CR4056, a novel imidazoline-2 receptor ligand, in rat models of inflammatory and neuropathic pain

    Directory of Open Access Journals (Sweden)

    Ferrari F

    2011-04-01

    Full Text Available Flora Ferrari1, Simonetta Fiorentino1, Laura Mennuni1, Paolo Garofalo1, Ornella Letari1, Stefano Mandelli2, Antonio Giordani3, Marco Lanza1, Gianfranco Caselli11Department of Pharmacology and Toxicology; 2Department of Medicinal Chemistry; 3R&D Chemistry Drug Development and OS, Rottapharm S.p.A., Monza (MB, ItalyAbstract: Two decades of investigations have failed to unequivocally clarify the functions and the molecular nature of imidazoline-2 receptors (I2R. However, there is robust pharmacological evidence for the functional modulation of monoamino oxidase (MAO and other important enzyme activities by I2 site ligands. Some compounds of this class proved to be active experimental tools in preventing both experimental pain and opioid tolerance and dependence. Unfortunately, even though these compounds bind with high potency to central I2 sites, they fail to represent a valid clinical opportunity due to their pharmacokinetic, selectivity or side-effects profile. This paper presents the preclinical profile of a novel I2 ligand (2-phenyl-6-(1H-imidazol-1ylquinazoline; [CR4056] that selectively inhibits the activity of human recombinant MAO-A in a concentration-dependent manner. A sub-chronic four day oral treatment of CR4056 increased norepinephrine (NE tissue levels both in the rat cerebral cortex (63.1% ± 4.2%; P<0.05 and lumbar spinal cord (51.3% ± 6.7%; P < 0.05. In the complete Freund's adjuvant (CFA rat model of inflammatory pain, CR4056 was found to be orally active (ED50 = 5.8 mg/kg, by mouth [p.o.]. In the acute capsaicin model, CR4056 completely blocked mechanical hyperalgesia in the injured hind paw (ED50 = 4.1 mg/kg, p.o.; ED100 = 17.9 mg/kg, p.o.. This effect was dose-dependently antagonized by the non-selective imidazoline I2/α2 antagonist idazoxan. In rat models of neuropathic pain, oral administration of CR4056 significantly attenuated mechanical hyperalgesia and allodynia. In summary, the present study suggests a novel

  5. The effects of patient-professional partnerships on the self-management and health outcomes for patients with chronic back pain: A quasi-experimental study.

    Science.gov (United States)

    Fu, Yu; Yu, Ge; McNichol, Elaine; Marczewski, Kathryn; José Closs, S

    2016-07-01

    Self-management may be a lifelong task for patients with chronic back pain. Research suggests that chronic pain self-management programmes have beneficial effects on patients' health outcome. Contemporary pain management theories and models also suggest that a good patient-professional partnership enhances patients' ability to self-manage their condition. (1) To investigate whether there is a reciprocal relationship between self-management of chronic back pain and health-related quality of life (HRQoL); (2) to examine the impact of a good patient-professional partnership on HRQoL, either directly, or indirectly via change in the ability to self-manage pain. This quasi-experimental study was designed to take place during routine service appointments and conducted in a community-based pain management service in the United Kingdom. A patient-professional partnership was established in which patients were actively involved in setting up goals and developing individualised care plans. Through this, health professionals undertook patients' health needs assessment, collaborated with patients to identify specific problems, provided written materials and delivered individualised exercise based on patients' life situation. Patients were recruited following initial consultation and followed up three months later. A total of 147 patients (65% female) with a mean age of 48 years (standard deviation (SD): 14 years) were enrolled in the study. Of these, 103 subjects completed the study. Patients were included if they were aged 18 and over, suffered from chronic back pain, had opted in to the clinic and had sufficient ability to read and understand English. Patients were excluded if they opted out this service after the initial assessment, suffered from malignant pain or required acute medical interventions for their pain relief. Self-reported measures of HRQoL, patient-professional partnerships and self-management ability were collected at baseline and three months later

  6. Rethinking the Psychogenic Model of Complex Regional Pain Syndrome: Somatoform Disorders and Complex Regional Pain Syndrome

    Science.gov (United States)

    Hill, Renee J.; Chopra, Pradeep; Richardi, Toni

    2012-01-01

    Abstract Explaining the etiology of Complex Regional Pain Syndrome (CRPS) from the psychogenic model is exceedingly unsophisticated, because neurocognitive deficits, neuroanatomical abnormalities, and distortions in cognitive mapping are features of CRPS pathology. More importantly, many people who have developed CRPS have no history of mental illness. The psychogenic model offers comfort to physicians and mental health practitioners (MHPs) who have difficulty understanding pain maintained by newly uncovered neuro inflammatory processes. With increased education about CRPS through a biopsychosocial perspective, both physicians and MHPs can better diagnose, treat, and manage CRPS symptomatology. PMID:24223338

  7. Effects of experimental muscle pain on shoulder-abduction force steadiness and muscle activity in healthy subjects

    DEFF Research Database (Denmark)

    Bandholm, Thomas Quaade; Rasmussen, Lars; Aagaard, Per

    2007-01-01

    We previously demonstrated that the steadiness of shoulder abduction is reduced in patients with subacromial impingement syndrome (SIS), which might be related to shoulder pain associated with the SIS. The aim of the present study was to examine the acute effects of experimental shoulder muscle p...

  8. Effects of a Pain Catastrophizing Induction on Sensory Testing in Women with Chronic Low Back Pain: A Pilot Study

    Directory of Open Access Journals (Sweden)

    Chloe J. Taub

    2017-01-01

    Full Text Available Pain catastrophizing, a pattern of negative cognitive-emotional responses to actual or anticipated pain, maintains chronic pain and undermines response to treatments. Currently, precisely how pain catastrophizing influences pain processing is not well understood. In experimental settings, pain catastrophizing has been associated with amplified pain processing. This study sought to clarify pain processing mechanisms via experimental induction of pain catastrophizing. Forty women with chronic low back pain were assigned in blocks to an experimental condition, either a psychologist-led 10-minute pain catastrophizing induction or a control (10-minute rest period. All participants underwent a baseline round of several quantitative sensory testing (QST tasks, followed by the pain catastrophizing induction or the rest period, and then a second round of the same QST tasks. The catastrophizing induction appeared to increase state pain catastrophizing levels. Changes in QST pain were detected for two of the QST tasks administered, weighted pin pain and mechanical allodynia. Although there is a need to replicate our preliminary results with a larger sample, study findings suggest a potential relationship between induced pain catastrophizing and central sensitization of pain. Clarification of the mechanisms through which catastrophizing affects pain modulatory systems may yield useful clinical insights into the treatment of chronic pain.

  9. Effects of a Pain Catastrophizing Induction on Sensory Testing in Women with Chronic Low Back Pain: A Pilot Study.

    Science.gov (United States)

    Taub, Chloe J; Sturgeon, John A; Johnson, Kevin A; Mackey, Sean C; Darnall, Beth D

    2017-01-01

    Pain catastrophizing, a pattern of negative cognitive-emotional responses to actual or anticipated pain, maintains chronic pain and undermines response to treatments. Currently, precisely how pain catastrophizing influences pain processing is not well understood. In experimental settings, pain catastrophizing has been associated with amplified pain processing. This study sought to clarify pain processing mechanisms via experimental induction of pain catastrophizing. Forty women with chronic low back pain were assigned in blocks to an experimental condition, either a psychologist-led 10-minute pain catastrophizing induction or a control (10-minute rest period). All participants underwent a baseline round of several quantitative sensory testing (QST) tasks, followed by the pain catastrophizing induction or the rest period, and then a second round of the same QST tasks. The catastrophizing induction appeared to increase state pain catastrophizing levels. Changes in QST pain were detected for two of the QST tasks administered, weighted pin pain and mechanical allodynia. Although there is a need to replicate our preliminary results with a larger sample, study findings suggest a potential relationship between induced pain catastrophizing and central sensitization of pain. Clarification of the mechanisms through which catastrophizing affects pain modulatory systems may yield useful clinical insights into the treatment of chronic pain.

  10. Effects of a Pain Catastrophizing Induction on Sensory Testing in Women with Chronic Low Back Pain: A Pilot Study

    Science.gov (United States)

    Sturgeon, John A.; Johnson, Kevin A.

    2017-01-01

    Pain catastrophizing, a pattern of negative cognitive-emotional responses to actual or anticipated pain, maintains chronic pain and undermines response to treatments. Currently, precisely how pain catastrophizing influences pain processing is not well understood. In experimental settings, pain catastrophizing has been associated with amplified pain processing. This study sought to clarify pain processing mechanisms via experimental induction of pain catastrophizing. Forty women with chronic low back pain were assigned in blocks to an experimental condition, either a psychologist-led 10-minute pain catastrophizing induction or a control (10-minute rest period). All participants underwent a baseline round of several quantitative sensory testing (QST) tasks, followed by the pain catastrophizing induction or the rest period, and then a second round of the same QST tasks. The catastrophizing induction appeared to increase state pain catastrophizing levels. Changes in QST pain were detected for two of the QST tasks administered, weighted pin pain and mechanical allodynia. Although there is a need to replicate our preliminary results with a larger sample, study findings suggest a potential relationship between induced pain catastrophizing and central sensitization of pain. Clarification of the mechanisms through which catastrophizing affects pain modulatory systems may yield useful clinical insights into the treatment of chronic pain. PMID:28348505

  11. Concept priming and pain: an experimental approach to understanding gender roles in sex-related pain differences.

    Science.gov (United States)

    Fowler, Stephanie L; Rasinski, Heather M; Geers, Andrew L; Helfer, Suzanne G; France, Christopher R

    2011-04-01

    Prior research has found that sex differences in pain are partially due to individual variations in gender roles. In a laboratory study, we tested the hypothesis that the presence of covert gender role cues can also moderate the extent to which women and men experience pain. Specifically, we varied gender role cues by asking male and female participants to write about instances in which they behaved in a stereotypically feminine, masculine, or neutral manner. Pain and cardiovascular reactivity to the cold pressor task were then assessed. Results revealed that, when primed with femininity, men reported less pain and anxiety from the cold pressor task than women. However, no differences existed between the sexes in the masculine or neutral prime conditions. The results indicate that covert gender cues can alter pain reports. Further, at least in some situations, feminine role cues may be more influential on pain reports than masculine role cues.

  12. Relevance of physical fitness levels and exercise-related beliefs for self-reported and experimental pain in fibromyalgia: an explorative study.

    Science.gov (United States)

    de Bruijn, Saskia T; van Wijck, Albert J M; Geenen, Rinie; Snijders, Tom J; van der Meulen, Wout J T M; Jacobs, Johannes W G; Veldhuijzen, Dieuwke Swaantje

    2011-09-01

    It has been suggested that low physical fitness is a contributor to pain in fibromyalgia and that exercise-related beliefs play a role in the persistence of this association. Yet the association between physical fitness and pain is hardly explored in detail. The aim of this exploratory study in patients with fibromyalgia was to investigate the association of physical fitness levels with self-reported and experimental pain as well as with pain catastrophizing and activity-avoidance beliefs. Physical fitness of 18 patients with fibromyalgia was examined using maximal ergocycling and the 6-minute walking test (6MWT). Pain intensity was assessed using self-report scales and quantitative sensory testing. A reduced walking distance on the 6MWT was correlated with more severe self-reported pain on the Fibromyalgia Impact Questionnaire (r = -0.52, P physically fit and experienced more severe pain. The results demonstrate some associations between physical fitness and pain in fibromyalgia and point to the importance of activity avoidance. Although the causal directionality of the associations needs substantiation in clinical research, the findings support the notion that low fitness and activity-avoidance beliefs should be targeted while treating pain in fibromyalgia.

  13. Reliability of four experimental mechanical pain tests in children

    Directory of Open Access Journals (Sweden)

    Soee AL

    2013-02-01

    Full Text Available Ann-Britt L Soee,1 Lise L Thomsen,2 Birte Tornoe,1,3 Liselotte Skov11Department of Pediatrics, Children’s Headache Clinic, Copenhagen University Hospital Herlev, Copenhagen, Denmark; 2Department of Neuropediatrics, Juliane Marie Centre, Copenhagen University Hospital Rigshospitalet, København Ø, Denmark; 3Department of Physiotherapy, Medical Department O, Copenhagen University Hospital Herlev, Herlev, DenmarkPurpose: In order to study pain in children, it is necessary to determine whether pain measurement tools used in adults are reliable measurements in children. The aim of this study was to explore the intrasession reliability of pressure pain thresholds (PPT in healthy children. Furthermore, the aim was also to study the intersession reliability of the following four tests: (1 Total Tenderness Score; (2 PPT; (3 Visual Analog Scale score at suprapressure pain threshold; and (4 area under the curve (stimulus–response functions for pressure versus pain.Participants and methods: Twenty-five healthy school children, 8–14 years of age, participated. Test 2, PPT, was repeated three times at 2 minute intervals on the same day to estimate PPT intrasession reliability using Cronbach’s alpha. Tests 1–4 were repeated after median 21 (interquartile range 10.5–22 days, and Pearson’s correlation coefficient was used to describe the intersession reliability.Results: The PPT test was precise and reliable (Cronbach’s alpha ≥ 0.92. All tests showed a good to excellent correlation between days (intersessions r = 0.66–0.81. There were no indications of significant systematic differences found in any of the four tests between days.Conclusion: All tests seemed to be reliable measurements in pain evaluation in healthy children aged 8–14 years. Given the small sample size, this conclusion needs to be confirmed in future studies.Keywords: repeatability, intraindividual reliability, pressure pain threshold, pain measurement, algometer

  14. Stress-Induced Chronic Visceral Pain of Gastrointestinal Origin

    Directory of Open Access Journals (Sweden)

    Beverley Greenwood-Van Meerveld

    2017-11-01

    stress-induced exacerbation of chronic visceral pain. Additionally, we will review the importance of specific experimental models of adult stress and ELS in enhancing our understanding of the basic molecular mechanisms of pain processing.

  15. Stress-Induced Chronic Visceral Pain of Gastrointestinal Origin

    Science.gov (United States)

    Greenwood-Van Meerveld, Beverley; Johnson, Anthony C.

    2017-01-01

    -induced exacerbation of chronic visceral pain. Additionally, we will review the importance of specific experimental models of adult stress and ELS in enhancing our understanding of the basic molecular mechanisms of pain processing. PMID:29213232

  16. Old and in pain: Enduring and situational effects of cultural aging stereotypes on older people's pain experiences.

    Science.gov (United States)

    Bernardes, S F; Marques, S; Matos, M

    2015-08-01

    This study aimed to investigate the interplay between enduring and situational aging stereotype (AS) effects in older adults' self-reports of clinical and experimentally induced pain. We expected that, as compared with the situational activation of positive AS or a neutral condition, the activation of negative AS would lead to more severe self-reports of clinical pain (H1, hypothesis 1), higher cold pressor task (CPT) pain threshold (H2) and lower CPT pain tolerance (H3), especially among older adults who more strongly endorsed AS. This was a prospective study across two moments in time. At time 1 (T1), 52 older adults (Mage  = 74.7; 51.9% women) filled out measures of cultural AS endorsement, clinical pain severity and interference. Three months afterwards (T2), some of these participants collaborated in an experimental study on the effects of AS activation on reported clinical pain (n = 40) and experimentally induced (using CPT) pain threshold and tolerance (n = 35). Our results supported H2, i.e., as compared with the activation of positive AS or a neutral condition, when negative AS were activated older adults showed higher CPT pain thresholds, but this effect was more salient among those who more strongly endorsed AS at T1. This study stresses the influence of cultural AS in older adults' pain experiences showing that the situational activation of negative AS greatly increases experimentally induced pain thresholds of elders who more strongly endorse those stereotypes. It also highlights the relevance of interventions at the level of the physical and/or social environments surrounding elders in pain. © 2014 European Pain Federation - EFIC®

  17. Beyond Negative Pain-Related Psychological Factors: Resilience Is Related to Lower Pain Affect in Healthy Adults.

    Science.gov (United States)

    Hemington, Kasey S; Cheng, Joshua C; Bosma, Rachael L; Rogachov, Anton; Kim, Junseok A; Davis, Karen D

    2017-09-01

    Resilience, a characteristic that enhances adaptation in response to stressful events, is a positive psychological factor that can predict and modulate health outcomes. However, resilience is rarely considered in pain research. Conversely, negative psychological factors (eg, anxiety, depression) are known to be related to the affective dimension of pain. It is critical to understand all potential psychological drivers of pain affect, a prominent component of chronic pain. We tested the hypothesis that higher resilience is associated with lower pain affect, above and beyond the predictive value of negative psychological factors. Healthy adults underwent psychophysical testing to acquire ratings of heat pain intensity and unpleasantness and completed the Resilience Scale, the State-Trait Anxiety Inventory (trait form), Beck Depression Inventory, Pain Catastrophizing Scale, and the Pain Vigilance and Attention Questionnaire. Multiple regression modeling (n = 68) showed resilience to be a negatively associated with pain affect (unpleasantness). Furthermore, in individuals with higher anxiety scores, resilience was protective against higher pain affect. This highlights the importance of resilience, a positive psychological factor, in the affective dimension of pain. This study is the first to assess a positive psychological factor and experimental pain affect, and has the potential to improve prediction of and treatment strategies for clinical pain. We report that resilience, a positive psychological factor, interacts with anxiety and is associated with heat pain affect (unpleasantness) in healthy individuals. Resilience may provide predictive value of chronic pain affect and treatment outcomes, and could be a target for behavioral therapy. Copyright © 2017 American Pain Society. Published by Elsevier Inc. All rights reserved.

  18. Cancer Pain Physiology

    DEFF Research Database (Denmark)

    Falk, Sarah; Bannister, Kirsty; Dickenson, Anthony

    2014-01-01

    Mechanisms of inflammatory and neuropathic pains have been elucidated and translated to patient care by the use of animal models of these pain states. Cancer pain has lagged behind since early animal models of cancer-induced bone pain were based on the systemic injection of carcinoma cells....... This precluded systematic investigation of specific neuronal and pharmacological alterations that occur in cancer-induced bone pain. In 1999, Schwei et al. described a murine model of cancer-induced bone pain that paralleled the clinical condition in terms of pain development and bone destruction, confined...... to the mouse femur. This model prompted related approaches and we can now state that cancer pain may include elements of inflammatory and neuropathic pains but also unique changes in sensory processing. Cancer induced bone pain results in progressive bone destruction, elevated osteoclast activity...

  19. Pulsed magnetic field enhances therapeutic efficiency of mesenchymal stem cells in chronic neuropathic pain model.

    Science.gov (United States)

    Mert, Tufan; Kurt, Akif Hakan; Altun, İdiris; Celik, Ahmet; Baran, Furkan; Gunay, Ismail

    2017-05-01

    Cell-based or magnetic field therapies as alternative approaches to pain management have been tested in several experimental pain models. The aim of this study therefore was to investigate the actions of the cell-based therapy (adipose tissue derived mesenchymal stem cells; ADMSC) or pulsed magnetic field (PMF) therapy and magneto-cell therapy (combination of ADMSC and PMF) in chronic constriction nerve injury model (CCI). The actions of individual ADMSC (route dependent [systemic or local], time-dependent [a day or a week after surgery]), or PMF and their combination (magneto-cell) therapies on hyperalgesia and allodynia were investigated by using thermal plantar test and a dynamic plantar aesthesiometer, respectively. In addition, various cytokine levels (IL-1β, IL-6, and IL-10) of rat sciatic nerve after CCI were analyzed. Following the CCI, both latency and threshold significantly decreased. ADMSC or PMF significantly increased latencies and thresholds. The combination of ADMSC with PMF even more significantly increased latency and threshold when compared with ADMSC alone. However, ADMSC-induced decrease in pro-inflammatory or increase in anti-inflammatory cytokines levels were partially prevented by PMF treatments. Present findings may suggest that both cell-based and magnetic therapies can effectively attenuate chronic neuropathic pain symptoms. Combined magneto-cell therapy may also efficiently reverse neuropathic signs. Bioelectromagnetics. 38:255-264, 2017. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

  20. Experimental orofacial pain and sensory deprivation lead to perceptual distortion of the face in healthy volunteers.

    Science.gov (United States)

    Dagsdóttir, Lilja Kristín; Skyt, Ina; Vase, Lene; Baad-Hansen, Lene; Castrillon, Eduardo; Svensson, Peter

    2015-09-01

    Patients suffering from persistent orofacial pain may sporadically report that the painful area feels "swollen" or "differently," a phenomenon that may be conceptualized as a perceptual distortion because there are no clinical signs of swelling present. Our aim was to investigate whether standardized experimental pain and sensory deprivation of specific orofacial test sites would lead to changes in the size perception of these face areas. Twenty-four healthy participants received either 0.2 mL hypertonic saline (HS) or local anesthetics (LA) into six regions (buccal, mental, lingual, masseter muscle, infraorbital and auriculotemporal nerve regions). Participants estimated the perceived size changes in percentage (0 % = no change, -100 % = half the size or +100 % = double the size), and somatosensory function was checked with tactile stimuli. The pain intensity was rated on a 0-10 Verbal Numerical Rating Scale (VNRS), and sets of psychological questionnaires were completed. HS and LA were associated with significant self-reported perceptual distortions as indicated by consistent increases in perceived size of the adjacent face areas (P ≤ 0.050). Perceptual distortion was most pronounced in the buccal region, and the smallest increase was observed in the auriculotemporal region. HS was associated with moderate levels of pain VNRS = 7.3 ± 0.6. Weak correlations were found between HS-evoked perceptual distortion and level of dissociation in two regions (P pain and transient sensory deprivation evoked perceptual distortions in all face regions and overall demonstrated the importance of afferent inputs for the perception of the face. We propose that perceptual distortion may be an important phenomenon to consider in persistent orofacial pain conditions.

  1. Chenopodium ambrosioides L. Reduces Synovial Inflammation and Pain in Experimental Osteoarthritis.

    Directory of Open Access Journals (Sweden)

    Gustavo P Calado

    Full Text Available The chronicity of osteoarthritis (OA, characterized by pain and inflammation in the joints, is linked to a glutamate receptor, N-methyl-D-aspartate (NMDA. The use of plant species such as Chenopodium ambrosioides L. (Amaranthaceae as NMDA antagonists offers a promising perspective. This work aims to analyze the antinociceptive and anti-inflammatory responses of the crude hydroalcoholic extract (HCE of C. ambrosioides leaves in an experimental OA model. Wistar rats were separated into six groups (n = 24: clean (C, negative control (CTL-, positive control (CTL+, HCE0.5, HCE5 and HCE50. The first group received no intervention. The other groups received an intra-articular injection of sodium monoiodoacetate (MIA (8 mg/kg on day 0. After six hours, they were orally treated with saline, Maxicam plus (meloxicam + chondroitin sulfate and HCE at doses of 0.5 mg/kg, 5 mg/kg and 50 mg/kg, respectively. After three, seven and ten days, clinical evaluations were performed (knee diameter, mechanical allodynia, mechanical hyperalgesia and motor activity. On the tenth day, after euthanasia, synovial fluid and draining lymph node were collected for cellular quantification, and cartilage was collected for histopathological analysis. Finally, molecular docking was performed to evaluate the compatibility of ascaridole, a monoterpene found in HCE, with the NMDA receptor. After the third day, HCE reduced knee edema. HCE5 showed less cellular infiltrate in the cartilage and synovium and lower intensities of allodynia from the third day and of hyperalgesia from the seventh day up to the last treatment day. The HCE5 and HCE50 groups improved in forced walking. In relation to molecular docking, ascaridole showed NMDA receptor binding affinity. C. ambrosioides HCE was effective in the treatment of OA because it reduced synovial inflammation and behavioral changes due to pain. This effect may be related to the antagonistic effect of ascaridole on the NMDA receptor.

  2. Sacroiliac joint pain: Prospective, randomised, experimental and comparative study of thermal radiofrequency with sacroiliac joint block.

    Science.gov (United States)

    Cánovas Martínez, L; Orduña Valls, J; Paramés Mosquera, E; Lamelas Rodríguez, L; Rojas Gil, S; Domínguez García, M

    2016-05-01

    To compare the analgesic effects between the blockade and bipolar thermal radiofrequency in the treatment of sacroiliac joint pain. Prospective, randomised and experimental study conducted on 60 patients selected in the two hospitals over a period of nine months, who had intense sacroiliac joint pain (Visual Analogue Scale [VAS]>6) that lasted more than 3 months. Patients were randomised into three groups (n=20): Group A (two intra-articular sacroiliac injections of local anaesthetic/corticosteroid guided by ultrasound in 7 days). Group B: conventional bipolar radiofrequency "palisade". Target points were the lateral branch nerves of S1, S2, and S3, distance needles 1cm. Group C: modified bipolar radiofrequency "palisade" (needle distance >1cm). Patients were evaluated at one month, three months, and one year. Demographic data, VAS reduction, and side effects of the techniques were assessed. One month after the treatment, pain reduction was >50% in the three groups PDolor. Publicado por Elsevier España, S.L.U. All rights reserved.

  3. Stress-Induced Visceral Pain: Toward Animal Models of Irritable-Bowel Syndrome and Associated Comorbidities

    Science.gov (United States)

    Moloney, Rachel D.; O’Mahony, Siobhain M.; Dinan, Timothy G.; Cryan, John F.

    2015-01-01

    Visceral pain is a global term used to describe pain originating from the internal organs, which is distinct from somatic pain. It is a hallmark of functional gastrointestinal disorders such as irritable-bowel syndrome (IBS). Currently, the treatment strategies targeting visceral pain are unsatisfactory, with development of novel therapeutics hindered by a lack of detailed knowledge of the underlying mechanisms. Stress has long been implicated in the pathophysiology of visceral pain in both preclinical and clinical studies. Here, we discuss the complex etiology of visceral pain reviewing our current understanding in the context of the role of stress, gender, gut microbiota alterations, and immune functioning. Furthermore, we review the role of glutamate, GABA, and epigenetic mechanisms as possible therapeutic strategies for the treatment of visceral pain for which there is an unmet medical need. Moreover, we discuss the most widely described rodent models used to model visceral pain in the preclinical setting. The theory behind, and application of, animal models is key for both the understanding of underlying mechanisms and design of future therapeutic interventions. Taken together, it is apparent that stress-induced visceral pain and its psychiatric comorbidities, as typified by IBS, has a multifaceted etiology. Moreover, treatment strategies still lag far behind when compared to other pain modalities. The development of novel, effective, and specific therapeutics for the treatment of visceral pain has never been more pertinent. PMID:25762939

  4. Predictive models of pain following root canal treatment: a prospective clinical study.

    Science.gov (United States)

    Arias, A; de la Macorra, J C; Hidalgo, J J; Azabal, M

    2013-08-01

    To determine the probability of the incidence, intensity, duration and triggering of post-endodontic pain, considering factors related to the patient (age, gender, medical evaluation) and to the affected tooth (group, location, number of canals, pulp vitality, preoperative pain, periapical radiolucencies, previous emergency access, presence of occlusal contacts with antagonist). A total of 500 one-visit root canal treatments (RCTs) were performed on patients referred to an endodontist. Shaping of root canals was performed manually with Gates-Glidden drills and K-Flexofiles, and apical patency was maintained with a size 10 file. A 5% NaOCl solution was used for irrigation, and canals were filled with lateral compaction and AH-Plus sealer. Independent factors were recorded during the treatment, and characteristics of post-endodontic pain (incidence, intensity, type and duration) were later surveyed through questionnaires. Of the 500 questionnaires, 374 were properly returned and split in two groups for two different statistical purposes: 316 cases were used to adjust the logistic regression models to predict each characteristic of post-endodontic pain using predictive factors, and the remaining 58 cases were used to test the validity of each model. The predictive models showed that the incidence of post-endodontic pain was significantly lower when the treated tooth was not a molar (P = 0.003), demonstrated periapical radiolucencies (P = 0.003), had no history of previous pain (P = 0.006) or emergency endodontic treatment (P = 0.045) and had no occlusal contact (P endodontic pain were generated and validated taking account of the interrelation of multiple concomitant clinical factors. A predictive model for triggering post-endodontic pain could not be established. © 2013 International Endodontic Journal. Published by John Wiley & Sons Ltd.

  5. Enhanced presurgical pain temporal summation response predicts post-thoracotomy pain intensity during the acute postoperative phase.

    Science.gov (United States)

    Weissman-Fogel, Irit; Granovsky, Yelena; Crispel, Yonathan; Ben-Nun, Alon; Best, Lael Anson; Yarnitsky, David; Granot, Michal

    2009-06-01

    Recent evidence points to an association between experimental pain measures obtained preoperatively and acute postoperative pain (POP). We hypothesized that pain temporal summation (TS) might be an additional predictor for POP insofar as it represents the neuroplastic changes that occur in the central nervous system following surgery. Therefore, a wide range of psychophysical tests (TS to heat and mechanical repetitive stimuli, pain threshold, and suprathreshold pain estimation) and personality tests (pain catastrophizing and anxiety levels) were administered prior to thoracotomy in 84 patients. POP ratings were evaluated on the 2nd and 5th days after surgery at rest (spontaneous pain) and in response to activity (provoked pain). Linear regression models revealed that among all assessed variables, enhanced TS and higher pain scores for mechanical stimulation were significantly associated with greater provoked POP intensity (overall r2 = 0.225, P = .008). Patients who did not demonstrate TS to both modalities reported lower scores of provoked POP as compared with patients who demonstrated TS in response to at least 1 modality (F = 4.59 P = .013). Despite the moderate association between pain catastrophizing and rest POP, none of the variables predicted the spontaneous POP intensity. These findings suggest that individual susceptibility toward a greater summation response may characterize patients who are potentially vulnerable to augmented POP. This study proposed the role of pain temporal summation assessed preoperatively as a significant psychophysical predictor for acute postoperative pain intensity. The individual profile of enhanced pain summation is associated with the greater likelihood of higher postoperative pain scores.

  6. Neurodynamic treatment did not improve pain and disability at two weeks in patients with chronic nerve-related leg pain: a randomised trial

    Directory of Open Access Journals (Sweden)

    Giovanni Ferreira

    2016-10-01

    Full Text Available Question: In people with nerve-related leg pain, does adding neurodynamic treatment to advice to remain active improve leg pain, disability, low back pain, function, global perceived effect and location of symptoms? Design: Randomised trial with concealed allocation and intention-to-treat analysis. Participants: Sixty participants with nerve-related leg pain recruited from the community. Interventions: The experimental group received four sessions of neurodynamic treatment. Both groups received advice to remain active. Outcome measures: Leg pain and low back pain (0, none, to 10, worst, Oswestry Disability Index (0, none, to 100, worst, Patient-Specific Functional Scale (0, unable to perform, to 30, able to perform, global perceived effect (–5 to 5 and location of symptoms were measured at 2 and 4 weeks after randomisation. Continuous outcomes were analysed by linear mixed models. Location of symptoms was assessed by relative risk (95% CI. Results: At 2 weeks, the experimental group did not have significantly greater improvement than the control group in leg pain (MD –1.1, 95% CI –2.3 to 0.1 or disability (MD –3.3, 95% CI –9.6 to 2.9. At 4 weeks, the experimental group experienced a significantly greater reduction in leg pain (MD –2.4, 95% CI –3.6 to –1.2 and low back pain (MD –1.5, 95% CI –2.8 to –0.2. The experimental group also improved significantly more in function at 2 weeks (MD 5.2, 95% CI 2.2 to 8.2 and 4 weeks (MD 4.7, 95% CI 1.7 to 7.8, as well as global perceived effect at 2 weeks (MD 2.5, 95% CI 1.6 to 3.5 and 4 weeks (MD 2.9, 95% CI 1.9 to 3.9. No significant between-group differences occurred in disability at 4 weeks and location of symptoms. Conclusion: Adding neurodynamic treatment to advice to remain active did not improve leg pain and disability at 2 weeks. Trial registration: NCT01954199. [Ferreira G, Stieven F, Araujo F, Wiebusch M, Rosa C, Plentz R, et al. (2016 Neurodynamic treatment did not improve

  7. A theory-based educational intervention targeting nurses' attitudes and knowledge concerning cancer-related pain management: A study protocol of a quasi-experimental design

    Directory of Open Access Journals (Sweden)

    Gustafsson Markus

    2011-09-01

    Full Text Available Abstract Background Pain is one of the most frequent problems among patients diagnosed with cancer. Despite the availability of effective pharmacological treatments, this group of patients often receives less than optimal treatment. Research into nurses' pain management highlights certain factors, such as lack of knowledge and attitudes and inadequate procedures for systematic pain assessment, as common barriers to effective pain management. However, educational interventions targeting nurses' pain management have shown promise. As cancer-related pain is also known to have a negative effect on vital aspects of the patient's life, as well as being commonly associated with problems such as sleep, fatigue, depression and anxiety, further development of knowledge within this area is warranted. Methods/design A quasi-experimental study design will be used to investigate whether the implementation of guidelines for systematic daily pain assessments following a theory-based educational intervention will result in an improvement in knowledge and attitude among nurses. A further aim is to investigate whether the intervention that targets nurses' behaviour will improve hospital patients' perception of pain. Data regarding nurses' knowledge and attitudes to pain (primary outcome, patient perception regarding pain (secondary outcome, together with socio-demographic variables, will be collected at baseline and at four weeks and 12 weeks following the intervention. Discussion Nursing care is nowadays acknowledged as an increasingly complicated activity and "nursing complexity is such that it can be seen as the quintessential complex intervention." To be able to change and improve clinical practice thus requires multiple points of attack appropriate to meet complex challenges. Consequently, we expect the theory-based intervention used in our quasi-experimental study to improve care as well as quality of life for this group of patients and we also envisage that

  8. A theory-based educational intervention targeting nurses' attitudes and knowledge concerning cancer-related pain management: a study protocol of a quasi-experimental design.

    Science.gov (United States)

    Borglin, Gunilla; Gustafsson, Markus; Krona, Hans

    2011-09-23

    Pain is one of the most frequent problems among patients diagnosed with cancer. Despite the availability of effective pharmacological treatments, this group of patients often receives less than optimal treatment. Research into nurses' pain management highlights certain factors, such as lack of knowledge and attitudes and inadequate procedures for systematic pain assessment, as common barriers to effective pain management. However, educational interventions targeting nurses' pain management have shown promise. As cancer-related pain is also known to have a negative effect on vital aspects of the patient's life, as well as being commonly associated with problems such as sleep, fatigue, depression and anxiety, further development of knowledge within this area is warranted. A quasi-experimental study design will be used to investigate whether the implementation of guidelines for systematic daily pain assessments following a theory-based educational intervention will result in an improvement in knowledge and attitude among nurses. A further aim is to investigate whether the intervention that targets nurses' behaviour will improve hospital patients' perception of pain. Data regarding nurses' knowledge and attitudes to pain (primary outcome), patient perception regarding pain (secondary outcome), together with socio-demographic variables, will be collected at baseline and at four weeks and 12 weeks following the intervention. Nursing care is nowadays acknowledged as an increasingly complicated activity and "nursing complexity is such that it can be seen as the quintessential complex intervention." To be able to change and improve clinical practice thus requires multiple points of attack appropriate to meet complex challenges. Consequently, we expect the theory-based intervention used in our quasi-experimental study to improve care as well as quality of life for this group of patients and we also envisage that evidence-based guidelines targeting this patient group's pain

  9. Masticatory sensory-motor changes after an experimental chewing test influenced by pain catastrophizing and neck-pain-related disability in patients with headache attributed to temporomandibular disorders.

    Science.gov (United States)

    La Touche, Roy; Paris-Alemany, Alba; Gil-Martínez, Alfonso; Pardo-Montero, Joaquín; Angulo-Díaz-Parreño, Santiago; Fernández-Carnero, Josué

    2015-03-05

    Recent research has shown a relationship of craniomandibular disability with neck-pain-related disability has been shown. However, there is still insufficient information demonstrating the influence of neck pain and disability in the sensory-motor activity in patients with headache attributed to temporomandibular disorders (TMD). The purpose of this study was to investigate the influence of neck-pain-related disability on masticatory sensory-motor variables. An experimental case-control study investigated 83 patients with headache attributed to TMD and 39 healthy controls. Patients were grouped according to their scores on the neck disability index (NDI) (mild and moderate neck disability). Initial assessment included the pain catastrophizing scale and the Headache Impact Test-6. The protocol consisted of baseline measurements of pressure pain thresholds (PPT) and pain-free maximum mouth opening (MMO). Individuals were asked to perform the provocation chewing test, and measurements were taken immediately after and 24 hours later. During the test, patients were assessed for subjective feelings of fatigue (VAFS) and pain intensity. VAFS was higher at 6 minutes (mean 51.7; 95% CI: 50.15-53.26) and 24 hours after (21.08; 95% CI: 18.6-23.5) for the group showing moderate neck disability compared with the mild neck disability group (6 minutes, 44.16; 95% CI 42.65-45.67/ 24 hours after, 14.3; 95% CI: 11.9-16.7) and the control group. The analysis shows a decrease in the pain-free MMO only in the group of moderate disability 24 hours after the test. PPTs of the trigeminal region decreased immediately in all groups, whereas at 24 hours, a decrease was observed in only the groups of patients. PPTs of the cervical region decreased in only the group with moderate neck disability 24 hours after the test. The strongest negative correlation was found between pain-free MMO immediately after the test and NDI in both the mild (r = -0.49) and moderate (r = -0.54) neck disability

  10. Experimental allergic encephalomyelitis: peculiarities of pain-relieving therapy and place of anticonvulsants as analgetics

    Directory of Open Access Journals (Sweden)

    Nefyodov O.O.

    2015-11-01

    Full Text Available Multiple sclerosis (MS is the most common demyelinating disease affecting mainly young people of the working age (16-45 years and quickly leading to disability. Available data constitute that up to 80% of MS patients suffer from pain at different disease periods. Pain management and the analgesic drug choice in MS patients may be difficult. Anticonvulsant drugs possess an analgesic activity and are widely used in patients presenting painful neuropathic symptoms. Based on that, we aimed to investigate the nociceptive potential changes as well as the research-oriented behavior using the "open field" test in rat. An experimental animal equivalent of multiple sclerosis has been modeled, based on the methylprednisolone (M administration. Animals were also administered anticonvulsants (carbamazepine, topiramate, sodium volproat, pregabalin and gabapentin. The stu­dy showed advantages of gabapentin and pregabalin use in simulated disease treatment. This statement is based on the "open field" test results, where the motor-oriented rats’ behavior was evaluated. Administration of M+gabapentin and M+pregabalin showed positive dynamics of the motor activity: the number of squares crossed increased by 80.86% (p<0.05 and 81.73% (р<0.05 respectively. Maximum recovery of the research activity (peeking in "mink" was re­gis­tered in animals administered M+pregabalin: the increase rate was 300% (r<0.05 comparing with the 12th day of ex­periment. It was shown, that 5-days administration of M+gabapentin and M+pregabalin caused muscle tone impro­ve­ment by 190% (p<0.05 and 200% (p<0.05 respectively, comparing with animals with untreated multiple sclerosis. A sig­ni­fi­cant increase of analgesic activity of M+pregabalin and M+gabapentin combinations used together with me­thyl­pred­nisolone by 4.1 (p<0.05 and 3.6 (p<0.05 times was registered comparing with the initial methylprednisolone background.

  11. A review of the evidence linking adult attachment theory and chronic pain: presenting a conceptual model.

    Science.gov (United States)

    Meredith, Pamela; Ownsworth, Tamara; Strong, Jenny

    2008-03-01

    It is now well established that pain is a multidimensional phenomenon, affected by a gamut of psychosocial and biological variables. According to diathesis-stress models of chronic pain, some individuals are more vulnerable to developing disability following acute pain because they possess particular psychosocial vulnerabilities which interact with physical pathology to impact negatively upon outcome. Attachment theory, a theory of social and personality development, has been proposed as a comprehensive developmental model of pain, implicating individual adult attachment pattern in the ontogenesis and maintenance of chronic pain. The present paper reviews and critically appraises studies which link adult attachment theory with chronic pain. Together, these papers offer support for the role of insecure attachment as a diathesis (or vulnerability) for problematic adjustment to pain. The Attachment-Diathesis Model of Chronic Pain developed from this body of literature, combines adult attachment theory with the diathesis-stress approach to chronic pain. The evidence presented in this review, and the associated model, advances our understanding of the developmental origins of chronic pain conditions, with potential application in guiding early pain intervention and prevention efforts, as well as tailoring interventions to suit specific patient needs.

  12. Posttraumatic stress symptoms and the diathesis-stress model of chronic pain and disability in patients undergoing major surgery.

    Science.gov (United States)

    Martin, Andrea L; Halket, Eileen; Asmundson, Gordon J G; Flora, David B; Katz, Joel

    2010-01-01

    To (1) use structural equation modeling (SEM) to examine relationships proposed in Turk's diathesis-stress model of chronic pain and disability as well as (2) investigate what role, if any, posttraumatic stress symptoms (PTSS) play in predicting pain disability, relative to some of the other factors in the model. The study sample consisted of 208 patients scheduled for general surgery, 21 to 60 years of age (mean age=47.18 y, SD=9.72 y), who reported experiencing persistent pain for an average of 5.56 years (SD=7.90 y). At their preadmission hospital visit, patients completed the Anxiety Sensitivity Index, Pain Catastrophizing Scale, Pain Anxiety Symptoms Scale-20, Pain Disability Index, posttraumatic stress disorder Checklist, and rated the average intensity of their pain (0 to 10 numeric rating scale). SEM was used to test a model of chronic pain disability and to explore potential relationships between PTSS and factors in the diathesis-stress model. SEM results provided support for a model in which anxiety sensitivity predicted fear of pain and catastrophizing, fear of pain predicted escape/avoidance, and escape/avoidance predicted pain disability. Results also provided support for a feedback loop between disability and fear of pain. SEM analyses provided preliminary support for the inclusion of PTSS in the diathesis-stress model, with PTSS accounting for a significant proportion of the variance in pain disability. Results provide empirical support for aspects of Turk's diathesis-stress model in a sample of patients with persistent pain. Findings also offer preliminary support for the role of PTSS in fear-avoidance models of chronic pain.

  13. Promoting culturally competent chronic pain management using the clinically relevant continuum model.

    Science.gov (United States)

    Monsivais, Diane B

    2011-06-01

    This article reviews the culture of biomedicine and current practices in pain management education, which often merge to create a hostile environment for effective chronic pain care. Areas of cultural tensions in chronic pain frequently involve the struggle to achieve credibility regarding one's complaints of pain (or being believed that the pain is real) and complying with pain medication protocols. The clinically relevant continuum model is presented as a framework allowing providers to approach care from an evidence-based, culturally appropriate (patient centered) perspective that takes into account the highest level of evidence available, provider expertise, and patient preferences and values. Copyright © 2011 Elsevier Inc. All rights reserved.

  14. Can a theory-based educational intervention change nurses' knowledge and attitudes concerning cancer pain management? A quasi-experimental design.

    Science.gov (United States)

    Gustafsson, Markus; Borglin, Gunilla

    2013-08-19

    Registered Nurses (RNs) play an important role in caring for patients suffering from cancer pain. A lack of knowledge regarding pain management and the RNs' own perception of cancer pain could act as barriers to effective pain management. Educational interventions that target RNs' knowledge and attitudes have proved promising. However, an intervention consisting of evidence-based practice is a multifaceted process and demands behavioural and cognitive changes to sustain the effects of the intervention. Therefore, our study aimed to investigate if a theory-based educational intervention could change RNs' knowledge and attitudes to cancer pain and pain management, both four and 12 weeks after the start of the intervention. A quasi-experimental design with non-equivalent control groups was used. The primary outcome was measured using a modified version of the instrument Nurses' Knowledge and Attitudes Survey Regarding Pain (NKAS) at baseline, four weeks and 12 weeks after the start of the intervention to evaluate its persistence. The intervention's educational curriculum was based on the principles of Ajzen's Theory of Planned Behaviour and consisted of interactive learning activities conducted in workshops founded on evidence-based knowledge. The RN's own experiences from cancer pain management were used in the learning process. The theory-based educational intervention aimed at changing RNs knowledge and attitudes regarding cancer pain management measured by primary outcome NKAS resulted in a statistical significant (presearched and needs to be evaluated further in larger projects. Clinical Trials. Gov: NCT01313234.

  15. Acupuncture in the Management of Injury and Operative Pain Under Field Conditions.

    Science.gov (United States)

    1976-03-01

    id,, iI ne.e.siry andl’,:,ni’, I’ Acupuncture Analgesia, ’ Pain Control Orofacial Acupuncture, Tooth Pulp.. Regional Analgesia Tisdocument reports...experimental series. The primary Acupuncture points which presently enjoy maximal favor in terms of the control of orofacial pain (there are three; see below...be used to ideitify optimal waveforms for three critical Acupuncture "points" associated wit., orofacial pain control. The same model will then be

  16. Validation and Refinement of a Pain Information Model from EHR Flowsheet Data.

    Science.gov (United States)

    Westra, Bonnie L; Johnson, Steven G; Ali, Samira; Bavuso, Karen M; Cruz, Christopher A; Collins, Sarah; Furukawa, Meg; Hook, Mary L; LaFlamme, Anne; Lytle, Kay; Pruinelli, Lisiane; Rajchel, Tari; Settergren, Theresa Tess; Westman, Kathryn F; Whittenburg, Luann

    2018-01-01

    Secondary use of electronic health record (EHR) data can reduce costs of research and quality reporting. However, EHR data must be consistent within and across organizations. Flowsheet data provide a rich source of interprofessional data and represents a high volume of documentation; however, content is not standardized. Health care organizations design and implement customized content for different care areas creating duplicative data that is noncomparable. In a prior study, 10 information models (IMs) were derived from an EHR that included 2.4 million patients. There was a need to evaluate the generalizability of the models across organizations. The pain IM was selected for evaluation and refinement because pain is a commonly occurring problem associated with high costs for pain management. The purpose of our study was to validate and further refine a pain IM from EHR flowsheet data that standardizes pain concepts, definitions, and associated value sets for assessments, goals, interventions, and outcomes. A retrospective observational study was conducted using an iterative consensus-based approach to map, analyze, and evaluate data from 10 organizations. The aggregated metadata from the EHRs of 8 large health care organizations and the design build in 2 additional organizations represented flowsheet data from 6.6 million patients, 27 million encounters, and 683 million observations. The final pain IM has 30 concepts, 4 panels (classes), and 396 value set items. Results are built on Logical Observation Identifiers Names and Codes (LOINC) pain assessment terms and extend the need for additional terms to support interoperability. The resulting pain IM is a consensus model based on actual EHR documentation in the participating health systems. The IM captures the most important concepts related to pain. Schattauer GmbH Stuttgart.

  17. Comparison of Repeated Measurement Design and Mixed Models in Evaluation of the Entonox Effect on Labor Pain

    Directory of Open Access Journals (Sweden)

    Nasim Karimi

    2017-01-01

    Full Text Available Background & objectives: In many medical studies, the response variable is measured repeatedly over time to evaluate the treatment effect that is known as longitudinal study. The analysis method for this type of data is repeated measures ANOVA that uses only one correlation structure and the results are not valid with inappropriate correlation structure. To avoid this problem, a convenient alternative is mixed models. So, the aim of this study was to compare of mixed and repeated measurement models for examination of the Entonox effect on the labor pain. Methods: This experimental study was designed to compare the effect of Entonox and oxygen inhalation on pain relief between two groups. Data were analyzed using repeated measurement and mixed models with different correlation structures. Selection and comparison of proper correlation structures performed using Akaike information criterion, Bayesian information criterion and restricted log-likelihood. Data were analyzed using SPSS-22. Results: Results of our study showed that all variables containing analgesia methods, labor duration of the first and second stages, and time were significant in these tests. In mixed model, heterogeneous first-order autoregressive, first-order autoregressive, heterogeneous Toeplitz and unstructured correlation structures were recognized as the best structures. Also, all variables were significant in these structures. Unstructured variance covariance matrix was recognized as the worst structure and labor duration of the first and second stages was not significant in this structure. Conclusions: This study showed that the Entonox inhalation has a significant effect on pain relief in primiparous and it is confirmed by all of the models.

  18. The effect of Cordia platythyrsa on various experimental models of ...

    African Journals Online (AJOL)

    Ned

    2014-01-08

    Jan 8, 2014 ... investigating the analgesic and anti-inflammatory properties of C. platythyrsa using various animal models: writhing test ... inhibited acetic acid-induced pain though these effects were weaker than the effects of morphine. Although, the ..... visceral pain model is used generally for screening compounds for ...

  19. Asymmetric dimethylarginine may mediate increased heat pain threshold in experimental chronic kidney disease.

    Science.gov (United States)

    Kielstein, Jan T; Suntharalingam, Mayuren; Perthel, Ronny; Rong, Song; Martens-Lobenhoffer, Jens; Jäger, Kristin; Bode-Böger, Stefanie M; Nave, Heike

    2012-03-01

    Thermal sensitivity in uraemia is decreased. Non-selective synthetic nitric oxide synthase (NOS) inhibitors significantly attenuate thermal hyperalgesia in preclinical models. The aim of our study was to evaluate the effect of experimental uraemia, which is associated with an increase of the endogenous NOS inhibitor asymmetric dimethylarginine (ADMA), on thermal sensitivity in rats. Furthermore, we intended to study the effect of chronic ADMA infusion alone on thermal sensitivity. Male Sprague-Dawley rats (n = 54), 10 weeks old, weight 370-430 g, were randomly assigned to three groups receiving either (i) isotonic saline or (ii) ADMA via osmotic mini pumps or (iii) underwent 5/6 nephrectomy (Nx). After 14 days, 50% of all animals from all groups underwent thermal sensitivity testing and terminal blood draw. After 28 days, the remaining animals underwent the same procedures. Thermal sensitivity examination was performed by the hot-plate test, measuring time from heat exposition to first paw licking or jumping of the animal. While the median [interquartile range] latency time between heat exposition to first paw licking or jumping of the animal in the NaCl infusion group remained unchanged between Day 14 (8.4 [6.75-11.50] s) and Day 28 (7.35 [6.10-7.90] s) both, ADMA infusion and 5/6 nephrectomy tended to increase the thermal pain threshold at Day 14 (9.25 [6.55-12.18] s) and (9.50 [5.8 ± 11.0] s), respectively, compared to NaCl on Day 14 (8.4 [6.75-11.50] s). This difference became statistical significant at Day 28 where the median latency time in the ADMA group (13.10 [11.85-15.95] s) and in the 5/6 Nx group (13.50 [10.85-17.55] s) were significantly higher than in the NaCl group (7.35 [6.10-7.90] s). Induction of progressive renal failure in rats by 5/6 nephrectomy, which is accompanied by a marked increase of the serum levels of the endogenous NOS inhibitor ADMA, leads to a significantly increased heat pain threshold at 28 days. The sole infusion of ADMA into

  20. Behavioral cues to expand a pain model of the cognitively impaired elderly in long-term care

    Directory of Open Access Journals (Sweden)

    Burfield AH

    2012-07-01

    Full Text Available Allison H Burfield,1 Thomas TH Wan,2 Mary Lou Sole,3 James W Cooper41School of Nursing, College of Health and Human Services, University of North Carolina-Charlotte, Charlotte, NC, 2Administration, and Medical Education, Doctoral Program in Public Affairs, College of Health and Public Affairs, 3College of Nursing, University of Central Florida, Orlando, FL, 4College of Pharmacy, University of Georgia, Athens, GA, USABackground: The purpose of this study was to determine the relationship between hypothesized pain behaviors in the elderly and a measurement model of pain derived from the Minimum Data Set-Resident Assessment Instrument (MDS-RAI 2.0 items.Methods: This work included a longitudinal cohort recruited from Medicare-certified long-term care facilities across the United States. MDS data were collected from 52,996 residents (mean age 83.7 years. Structural equation modeling was used to build a measurement model of pain to test correlations between indicators and the fit of the model by cognitive status. The model evaluates the theoretical constructs of pain to improve how pain is assessed and detected within cognitive levels.Results: Using pain frequency and intensity as the only indicators of pain, the overall prevalence of pain was 31.2%; however, analysis by cognitive status showed that 47.7% of the intact group was in pain, while only 18.2% of the severely, 29.4% of the moderately, and 39.6% of the mildly cognitively impaired groups were experiencing pain. This finding supports previous research indicating that pain is potentially under-reported in severely cognitively impaired elderly nursing home residents. With adjustments to the measurement model, a revised format containing affective, behavioral, and inferred pain indicates a better fit of the data to include these domains, as a more complete measure of the pain construct.Conclusion: Pain has a significant effect on quality of life and long-term health outcomes in nursing home

  1. Neuromuscular adaptations predict functional disability independently of clinical pain and psychological factors in patients with chronic non-specific low back pain.

    Science.gov (United States)

    Dubois, Jean-Daniel; Abboud, Jacques; St-Pierre, Charles; Piché, Mathieu; Descarreaux, Martin

    2014-08-01

    Patients with chronic low back pain exhibit characteristics such as clinical pain, psychological symptoms and neuromuscular adaptations. The purpose of this study was to determine the independent contribution of clinical pain, psychological factors and neuromuscular adaptations to disability in patients with chronic low back pain. Clinical pain intensity, pain catastrophizing, fear-avoidance beliefs, anxiety, neuromuscular adaptations to chronic pain and neuromuscular responses to experimental pain were assessed in 52 patients with chronic low back pain. Lumbar muscle electromyographic activity was assessed during a flexion-extension task (flexion relaxation phenomenon) to assess both chronic neuromuscular adaptations and neuromuscular responses to experimental pain during the task. Multiple regressions showed that independent predictors of disability included neuromuscular adaptations to chronic pain (β=0.25, p=0.006, sr(2)=0.06), neuromuscular responses to experimental pain (β=-0.24, p=0.011, sr(2)=0.05), clinical pain intensity (β=0.28, p=0.002, sr(2)=0.08) and psychological factors (β=0.58, ppain intensity and psychological factors, and contribute to inter-individual differences in patients' disability. This suggests that disability, in chronic low back pain patients, is determined by a combination of factors, including clinical pain, psychological factors and neuromuscular adaptations. Copyright © 2014 Elsevier Ltd. All rights reserved.

  2. The Role of Cartilage Stress in Patellofemoral Pain

    Science.gov (United States)

    Besier, Thor F.; Pal, Saikat; Draper, Christine E.; Fredericson, Michael; Gold, Garry E.; Delp, Scott L.; Beaupré, Gary S.

    2015-01-01

    Purpose Elevated cartilage stress has been identified as a potential mechanism for retropatellar pain; however, there are limited data in the literature to support this mechanism. Females are more likely to develop patellofemoral pain than males, yet the causes of this dimorphism are unclear. We used experimental data and computational modeling to determine whether patients with patellofemoral pain had elevated cartilage stress compared to pain-free controls and test the hypothesis that females exhibit greater cartilage stress than males. Methods We created finite element models of 24 patients with patellofemoral pain (11 males; 13 females) and 16 pain-free controls (8 males; 8 females) to estimate peak patellar cartilage stress (strain energy density) during a stair climb activity. Simulations took into account cartilage morphology from MRI, joint posture from weight-bearing MRI, and muscle forces from an EMG-driven model. Results We found no difference in peak patellar strain energy density between patellofemoral pain (1.9 ± 1.23 J/m3) and control subjects (1.66 ± 0.75 J/m3, p=0.52). Females exhibited greater cartilage stress compared to males (2.2 vs 1.3 J/m3, respectively, p=0.0075), with large quadriceps muscle forces (3.7BW females vs 3.3BW males) and 23% smaller joint contact area (females: 467 ± 59 mm2 vs males: 608 ± 95mm2). Conclusion Patellofemoral pain patients did not display significantly greater patellar cartilage stress compared to pain-free controls; however, there was a great deal of subject variation. Females exhibited greater peak cartilage stress compared to males, which might explain the greater prevalence of patellofemoral pain in females compared to males but other mechanical and biological factors are clearly involved in this complex pathway to pain. PMID:25899103

  3. Addicted to Pain: A Preliminary Model of Sexual Masochism as Addiction.

    Science.gov (United States)

    Kurt, Holly; Ronel, Natti

    2017-11-01

    An exploratory, qualitative, phenomenological study focused on the experience of pain while participating in sexual masochistic acts. Semi-structured interviews were conducted with nine individuals (four female, five male) who regularly participate in sexually masochistic acts and point to pain as central to their experience. Qualitative analysis of the data revealed several key characteristics of the participant's experience: the first time, intoxication, craving and withdrawal, tolerance, pain as control, and the pain inducing partner. The findings indicate that the way pain is experienced while mitigated through masochistic behavior creates an addictive process that coincides with a chronic behavioral spin contextualization. This article presents a preliminary model of addiction to physical pain in light of the Diagnostic and Statistical Manual of Mental Disorders (5th ed.; DSM-5) definition of substance-related and addictive disorders and the behavioral spin theory.

  4. Alteration of cancer pain-related signals by radiation: Proteomic analysis in an animal model with cancer bone invasion

    International Nuclear Information System (INIS)

    Park, Hee Chul; Seong, Jinsil; An, Jung Hee; Kim, Jiyoung; Kim, Un Jung; Lee, Bae Whan

    2005-01-01

    Purpose: Although radiotherapy is highly effective in relieving bone pain due to cancer invasion, its mechanism remains unclear. The aim of this study was to explore this mechanism in an animal model system. Methods and Materials: A hind paw model of cancer pain was developed by transplanting a murine hepatocarcinoma, HCa-1, into the periosteal membrane of the foot dorsum of C3H/HeJ mice. Bone invasion from HCa-1 was histopathologically confirmed from sequential tumor sampling. For three experimental groups, a control (N), tumor without radiation (T), and tumor with radiation (TR), the development and level of pain were objectively examined in mice with a growing tumor by assessing pain-associated behavior. The differential expression of pain-related signals in the spinal cord was analyzed by proteomic analysis using high-resolution two-dimensional gel electrophoresis (2-DE) and mass spectrometry, and those of proteins by Western blotting. The pain-mediating neurotransmitters in the spinal cord were also examined by immunohistochemical staining for calcitonin gene-related peptide (CGRP) and substance P. Results: In the histopathologic examinations, bone invasion from HCa-1 was seen from Day 7 and was evident at Day 14 after transplantation, and measurable pain-associated behaviors were developed from Day 7. After 25 Gy of radiation to the tumors, the objective level of pain in the TR group decreased, with higher thresholds to mechanical and thermal stimulation than in the T group. From the 2-DE of spinal cord, 107 spots were identified; 12 proteins were changed more than fivefold because of tumor formation but then reversed after radiation in the tumor-bearing mice. The proteins involved included secretagogin, syntenin, P2X purinoreceptor 6 (P2X6), and Ca 2+ /Calmodulin-dependent protein kinase 1 (CaM kinase 1), the functions of which have been known to be involved in the Ca 2+ -signaling cascade, ATP-mediated fast synaptic transmission, or control of vesicular

  5. Alteration of cancer pain-related signals by radiation: Proteomic analysis in an animal model with cancer bone invasion

    Energy Technology Data Exchange (ETDEWEB)

    Park, Hee Chul [Department of Radiation Oncology, Hallym University, Chuncheon (Korea, Republic of); Seong, Jinsil [Department of Radiation Oncology, Brain Korea 21 Project for Medicine, Yonsei University, Seoul (Korea, Republic of); An, Jung Hee [Department of Radiation Oncology, Brain Korea 21 Project for Medicine, Yonsei University, Seoul (Korea, Republic of); Kim, Jiyoung [Department of Radiation Oncology, Brain Korea 21 Project for Medicine, Yonsei University, Seoul (Korea, Republic of); Kim, Un Jung [Yonsei Medical Research Center, Brain Korea 21 Project for Medicine, Yonsei University, Seoul (Korea, Republic of); Lee, Bae Whan [Yonsei Medical Research Center, Brain Korea 21 Project for Medicine, Yonsei University, Seoul (Korea, Republic of)

    2005-04-01

    Purpose: Although radiotherapy is highly effective in relieving bone pain due to cancer invasion, its mechanism remains unclear. The aim of this study was to explore this mechanism in an animal model system. Methods and Materials: A hind paw model of cancer pain was developed by transplanting a murine hepatocarcinoma, HCa-1, into the periosteal membrane of the foot dorsum of C3H/HeJ mice. Bone invasion from HCa-1 was histopathologically confirmed from sequential tumor sampling. For three experimental groups, a control (N), tumor without radiation (T), and tumor with radiation (TR), the development and level of pain were objectively examined in mice with a growing tumor by assessing pain-associated behavior. The differential expression of pain-related signals in the spinal cord was analyzed by proteomic analysis using high-resolution two-dimensional gel electrophoresis (2-DE) and mass spectrometry, and those of proteins by Western blotting. The pain-mediating neurotransmitters in the spinal cord were also examined by immunohistochemical staining for calcitonin gene-related peptide (CGRP) and substance P. Results: In the histopathologic examinations, bone invasion from HCa-1 was seen from Day 7 and was evident at Day 14 after transplantation, and measurable pain-associated behaviors were developed from Day 7. After 25 Gy of radiation to the tumors, the objective level of pain in the TR group decreased, with higher thresholds to mechanical and thermal stimulation than in the T group. From the 2-DE of spinal cord, 107 spots were identified; 12 proteins were changed more than fivefold because of tumor formation but then reversed after radiation in the tumor-bearing mice. The proteins involved included secretagogin, syntenin, P2X purinoreceptor 6 (P2X6), and Ca{sup 2+}/Calmodulin-dependent protein kinase 1 (CaM kinase 1), the functions of which have been known to be involved in the Ca{sup 2+}-signaling cascade, ATP-mediated fast synaptic transmission, or control of

  6. Modeling the onset and offset of dental pain relief by ibuprofen.

    Science.gov (United States)

    Li, Hanbin; Mandema, Jaap; Wada, Russell; Jayawardena, Shyamalie; Desjardins, Paul; Doyle, Geraldine; Kellstein, David

    2012-01-01

    Onset and offset of dental pain relief by ibuprofen following third molar extraction were modeled in a randomized, double-blind, placebo-controlled, parallel-group, 8-hour study of patients receiving either a novel effervescent ibuprofen tablet (400 mg; N = 30), standard ibuprofen tablets (Nurofen(®) 2 × 200 mg; N = 22), or placebo (N = 37). An Emax model was fit to pain relief scores. Linear hazard models were used to analyze the time to first perceptible relief (TFPR), the time to meaningful pain relief (TMPR), and time to remedication (REMD). Nomograms were created to correlate TFPR, TMPR, and REMD with different ibuprofen pharmacokinetic profiles. Effervescent ibuprofen was absorbed rapidly with 95% completion within 15 minutes. Maximum pain relief score by ibuprofen was 1.8 units greater than placebo, with an EC50 (effect-site) for ibuprofen concentration of 10.2 µg·mL(-1). The likelihood to achieve TFPR and TMPR was doubled for every 10 µg·mL(-1) increase in ibuprofen plasma concentration. REMD risk decreased 40-fold as the categorical pain relief score increased from 0 to 3. Rapid absorption of ibuprofen effervescent resulted in an earlier TFPR and TMPR, and a lower REMD rate than standard ibuprofen. The nomograms may be useful in predicting the onset and offset of new faster acting ibuprofen formulations, based on pharmacokinetic profiles.

  7. Personalized pain medicine: the clinical value of psychophysical assessment of pain modulation profile.

    Science.gov (United States)

    Granovsky, Yelena; Yarnitsky, David

    2013-01-01

    Experimental pain stimuli can be used to simulate patients' pain experience. We review recent developments in psychophysical pain testing, focusing on the application of the dynamic tests-conditioned pain modulation (CPM) and temporal summation (TS). Typically, patients with clinical pain of various types express either less efficient CPM or enhanced TS, or both. These tests can be used in prediction of incidence of acquiring pain and of its intensity, as well as in assisting the correct choice of analgesic agents for individual patients. This can help to shorten the commonly occurring long and frustrating process of adjusting analgesic agents to the individual patients. We propose that evaluating pain modulation can serve as a step forward in individualizing pain medicine.

  8. Testing the impact of a multimedia video CD of patient-controlled analgesia on pain knowledge and pain relief in patients receiving surgery.

    Science.gov (United States)

    Chen, Hsing-Hsia; Yeh, Mei-Ling; Yang, Hui-Ju

    2005-07-01

    This study aimed to develop a multimedia video CD (VCD) of patient-controlled analgesia (PCA) and test its effects on pain knowledge and pain relief in patients receiving surgery. This multimedia VCD of PCA was created to convey fundamental knowledge to both patients and their family members and help patients properly utilize PCA devices to relieve pain and improve recovery. The content of multimedia VCD of PCA included pre-admission pain education, introduction of PCA, nursing care procedures, and questions and answers. This study used a quasi-experimental research design to test effects of the multimedia education program in the experimental group of 30 subjects compared to the control subjects of equal number (without the multimedia VCD of PCA). (1) The intervention of multimedia VCD of PCA resulted in a statistically significant difference in pain knowledge between the experimental and control groups. (2) Subjects in the experimental group obtained a better outcome of pain relief compared to control subjects. (3) Subjects in the experimental group indicated that the multimedia VCD of PCA indeed helped them effectively operate their PCA devices to relieve surgery pain. The clinical application of the multimedia VCD of PCA could help patients improve knowledge on pain, learn how to use PCA devices, achieve proper pain relief, and increase effectiveness of recovery activities.

  9. Motivational and behavioural models of change: A longitudinal analysis of change among men with chronic haemophilia-related joint pain.

    Science.gov (United States)

    Elander, J; Richardson, C; Morris, J; Robinson, G; Schofield, M B

    2017-09-01

    Motivational and behavioural models of adjustment to chronic pain make different predictions about change processes, which can be tested in longitudinal analyses. We examined changes in motivation, coping and acceptance among 78 men with chronic haemophilia-related joint pain. Using cross-lagged regression analyses of changes from baseline to 6 months as predictors of changes from 6 to 12 months, with supplementary structural equation modelling, we tested two models in which motivational changes influence behavioural changes, and one in which behavioural changes influence motivational changes. Changes in motivation to self-manage pain influenced later changes in pain coping, consistent with the motivational model of pain self-management, and also influenced later changes in activity engagement, the behavioural component of pain acceptance. Changes in activity engagement influenced later changes in pain willingness, consistent with the behavioural model of pain acceptance. Based on the findings, a combined model of changes in pain self-management and acceptance is proposed, which could guide combined interventions based on theories of motivation, coping and acceptance in chronic pain. This study adds longitudinal evidence about sequential change processes; a test of the motivational model of pain self-management; and tests of behavioural versus motivational models of pain acceptance. © 2017 European Pain Federation - EFIC®.

  10. Prediction of pain in orthodontic patients based on preoperative pain assessment

    Science.gov (United States)

    Zheng, Baoyu; Ren, Manman; Lin, Feiou; Yao, Linjie

    2016-01-01

    Aim To investigate whether pretreatment assessment of experimental pain can predict the level of pain after archwire placement. Methods One hundred and twenty-one general university students seeking orthodontic treatment were enrolled in this study. A cold pressor test was performed to estimate the pain tolerance of subjects before treatment. Self-reported pain intensity was calculated using a 10 cm visual analog scale during the 7 days after treatment. The relationship between pain tolerance and orthodontic pain was analyzed using Spearman’s correlation analysis. Results The maximum mean level of pain intensity occurred at 24 hours after bonding (53.31±16.13) and fell to normal levels at day 7. Spearman’s correlation analysis found a moderate positive association between preoperative pain tolerance and self-reported pain after archwire placement (P0.05). Conclusion A simple and noninvasive preoperative sensory test (the cold pressor test) was useful in predicting the risk of developing unbearable pain in patients after archwire placement. Self-reported pain after archwire placement decreased as individual pain tolerance increased. PMID:27042019

  11. Can multivariate models based on MOAKS predict OA knee pain? Data from the Osteoarthritis Initiative

    Science.gov (United States)

    Luna-Gómez, Carlos D.; Zanella-Calzada, Laura A.; Galván-Tejada, Jorge I.; Galván-Tejada, Carlos E.; Celaya-Padilla, José M.

    2017-03-01

    Osteoarthritis is the most common rheumatic disease in the world. Knee pain is the most disabling symptom in the disease, the prediction of pain is one of the targets in preventive medicine, this can be applied to new therapies or treatments. Using the magnetic resonance imaging and the grading scales, a multivariate model based on genetic algorithms is presented. Using a predictive model can be useful to associate minor structure changes in the joint with the future knee pain. Results suggest that multivariate models can be predictive with future knee chronic pain. All models; T0, T1 and T2, were statistically significant, all p values were 0.60.

  12. Investigation into the effects of using two or four acupuncture needles with bidirectional rotation on experimentally-induced contact heat pain in healthy subjects.

    Science.gov (United States)

    Paley, Carole A; Johnson, Mark I

    2015-02-01

    There is growing evidence from experimental studies that the acupuncture dose or technique influences the speed of onset of hypoalgesia. The aim of this study was to investigate the effects of acupuncture using two or four needles on experimental contact thermal pain in healthy volunteers. Forty two participants were randomised into three groups: four-needle group (LI4, LI11, LI10, TE5), two-needle group (verum at LI4, LI11 and mock at LI10, TE5) and mock acupuncture group (LI4, LI11, LI10, TE5). Each participant rated pain intensity (visual analogue scale, VAS) to a series of noxious stimuli administered to the forearm 2°C above the heat pain threshold during needling and immediately after removal of the needles. Experimentally-induced heat pain intensity (VAS) during and after the intervention was lower than pre-intervention but there were no statistically significant differences in this change between groups. There were no statistically significant differences between groups in the time taken for pain intensity to decrease by 33% from pre-intervention. However, a 33% decrease in pain intensity within 3 min of needle insertion was observed for 13 participants (92.9%) in the four-needle group compared with 66.7% of participants in the two-needle group and 57.1% in the mock acupuncture group. There was less variance in VAS in the four-needle group, suggesting more consistency in hypoalgesic response when using more needles. There is tentative evidence that four needles may be superior to two needles in generating rapid onset hypoalgesia. The findings suggest that further investigation is warranted. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

  13. An improved behavioural assay demonstrates that ultrasound vocalizations constitute a reliable indicator of chronic cancer pain and neuropathic pain

    Directory of Open Access Journals (Sweden)

    Selvaraj Deepitha

    2010-03-01

    Full Text Available Abstract Background On-going pain is one of the most debilitating symptoms associated with a variety of chronic pain disorders. An understanding of mechanisms underlying on-going pain, i.e. stimulus-independent pain has been hampered so far by a lack of behavioural parameters which enable studying it in experimental animals. Ultrasound vocalizations (USVs have been proposed to correlate with pain evoked by an acute activation of nociceptors. However, literature on the utility of USVs as an indicator of chronic pain is very controversial. A majority of these inconsistencies arise from parameters confounding behavioural experiments, which include novelty, fear and stress due to restrain, amongst others. Results We have developed an improved assay which overcomes these confounding factors and enables studying USVs in freely moving mice repetitively over several weeks. Using this improved assay, we report here that USVs increase significantly in mice with bone metastases-induced cancer pain or neuropathic pain for several weeks, in comparison to sham-treated mice. Importantly, analgesic drugs which are known to alleviate tumour pain or neuropathic pain in human patients significantly reduce USVs as well as mechanical allodynia in corresponding mouse models. Conclusions We show that studying USVs and mechanical allodynia in the same cohort of mice enables comparing the temporal progression of on-going pain (i.e. stimulus-independent pain and stimulus-evoked pain in these clinically highly-relevant forms of chronic pain.

  14. Short-Term Sensorimotor Effects of Experimental Occlusal Interferences on the Wake-Time Masseter Muscle Activity of Females with Masticatory Muscle Pain.

    Science.gov (United States)

    Cioffi, Iacopo; Farella, Mauro; Festa, Paola; Martina, Roberto; Palla, Sandro; Michelotti, Ambrosina

    2015-01-01

    To investigate the effects of the application of an acute alteration of the occlusion (ie, interference) on the habitual masseter electromyographic (EMG) activity of females with temporomandibular disorders (TMD)-related muscular pain during wakefulness. Seven female volunteers with masticatory myofascial pain participated in a crossover randomized clinical trial. Gold foils were glued on an occlusal contact area (active occlusal interference, AI) or on the vestibular surface of the same molar (dummy interference, DI) and left for 8 days. The masseter electromyogram was recorded during wakefulness in the natural environment by portable recorders under interference-free, dummy-interference, and active-interference conditions. The number, amplitude, and duration of EMG signal fractions with amplitudes above 10% of the maximum voluntary contraction (activity periods, APs) were computed in all experimental conditions. Muscle pain, headache, and perceived stress were each assessed with a visual analog scale (VAS), and an algometer was used to assess masseter and temporalis pressure pain thresholds. Data were analyzed by means of analysis of variance. The frequency and duration of the recorded APs did not differ significantly between the experimental conditions (P>.05), but a small and significant reduction of the EMG mean amplitude of the APs occurred with AI (P.05). An active occlusal interference in female volunteers with masticatory muscle pain had little influence on the masseter EMG activity pattern during wakefulness and did not affect the pressure tenderness of the masseter and temporalis.

  15. Comparison of QuadrapolarTM radiofrequency lesions produced by standard versus modified technique: an experimental model

    Directory of Open Access Journals (Sweden)

    Safakish R

    2017-06-01

    Full Text Available Ramin Safakish Allevio Pain Management Clinic, Toronto, ON, Canada Abstract: Lower back pain (LBP is a global public health issue and is associated with substantial financial costs and loss of quality of life. Over the years, different literature has provided different statistics regarding the causes of the back pain. The following statistic is the closest estimation regarding our patient population. The sacroiliac (SI joint pain is responsible for LBP in 18%–30% of individuals with LBP. Quadrapolar™ radiofrequency ablation, which involves ablation of the nerves of the SI joint using heat, is a commonly used treatment for SI joint pain. However, the standard Quadrapolar radiofrequency procedure is not always effective at ablating all the sensory nerves that cause the pain in the SI joint. One of the major limitations of the standard Quadrapolar radiofrequency procedure is that it produces small lesions of ~4 mm in diameter. Smaller lesions increase the likelihood of failure to ablate all nociceptive input. In this study, we compare the standard Quadrapolar radiofrequency ablation technique to a modified Quadrapolar ablation technique that has produced improved patient outcomes in our clinic. The methodology of the two techniques are compared. In addition, we compare results from an experimental model comparing the lesion sizes produced by the two techniques. Taken together, the findings from this study suggest that the modified Quadrapolar technique provides longer lasting relief for the back pain that is caused by SI joint dysfunction. A randomized controlled clinical trial is the next step required to quantify the difference in symptom relief and quality of life produced by the two techniques. Keywords: lower back pain, radiofrequency ablation, sacroiliac joint, Quadrapolar radiofrequency ablation

  16. Effects of perceived and exerted pain control on neural activity during pain relief in experimental heat hyperalgesia: a fMRI study.

    Science.gov (United States)

    Mohr, C; Leyendecker, S; Petersen, D; Helmchen, C

    2012-04-01

    Perceived control over pain can attenuate pain perception by mechanisms of endogenous pain control and emotional reappraisal irrespective of whether this control is exerted or only perceived. Self-initiated termination of pain elicits different expectations of subsequent pain relief as compared to perceived pain control. It is unknown whether and how this perceived vs. exerted control on pain differs and affects subsequent pain relief. Using fMRI, we studied two factors of pain control on pain relief: the (i) sense of control (perceived control but no execution) and (ii) the execution of control (exerted control). To account for the impact of factual execution of pain control on pain relief we applied bearable short and hardly bearable long contact-heat stimuli which were applied either controllable or not. Using controllability as factor, there was dissociable neural activity during pain relief: following the perceived control condition neural activity was found in the orbitofrontal and mediofrontal cortex and, following the exerted control condition, in the anterolateral and dorsolateral prefrontal cortex and posterior parietal cortex. We conclude that (i) pain controllability has an impact on pain relief and (ii) the prefrontal cortex shows dissociable neural activity during pain relief following exerted vs. perceived pain control. This might reflect the higher grade of uncertainty during pain relief following perceived pain control mediated by the orbitofrontal and medial prefrontal cortex and processes of working memory and updating expectations during pain relief following exerted control mediated by the lateral prefrontal cortex. © 2011 European Federation of International Association for the Study of Pain Chapters.

  17. Effects of a Peer-Led Pain Management Program for Nursing Home Residents with Chronic Pain: A Pilot Study.

    Science.gov (United States)

    Tse, Mimi Mun Yee; Yeung, Suey Shuk Yu; Lee, Paul Hong; Ng, Shamay Sheung Mei

    2016-09-01

    OBJECTIVES : To examine the feasibility of a peer-led pain management program among nursing home residents. DESIGN : A quasi-experimental design. SETTING : Two nursing homes. SUBJECTS : Fifty nursing home residents. METHODS : The experimental group (n = 32) was given a 12-week group-based peer-led pain management program. There were two 1-hour sessions per week. Education in pain and demonstrations of nonpharmacological pain management strategies were provided. The research team and 12 trained peers led the sessions. The control group (n = 18) received one 1-hour session of pain management program each week over 12 weeks from the research team only. Outcome measures for the participants were collected at baseline (P1) and at week 12 (P2). Data from peer volunteers were collected prior to training (V1) and at week 12 (V2). T-tests were used to compare the differences in outcome measures collected at two time points. RESULTS : There was a significant reduction in pain intensity from 5.8 ± 2.6 (P1) to 3.4 ± 2.5 (P2) for the experimental group (p = 0.003) and from 6.3 ± 3.0 (P1) to 3.1 ± 2.4 (P2) for the control group (p = 0.001). Activities of daily living significantly improved for both the experimental group (p = 0.008) and the control group (p = 0.014). There was an enhancement in happiness level for the experimental group (p pain management knowledge (2.9 ± 2.6 to 8.1 ± 1.2, p pain management program was feasible and has potential in relieving chronic pain and enhancing the physical and psychological health of nursing home residents. © 2016 American Academy of Pain Medicine. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  18. Investigating the affective component of pain: no startle modulation by tonic heat pain in startle responsive individuals.

    Science.gov (United States)

    Horn, Claudia; Schaller, Jörg; Lautenbacher, Stefan

    2012-06-01

    Experimental tonic pain has been assumed to equal clinical pain by triggering sizeable affective responses. A psycho-physiological indicator of defensive affective-motivational responses is the startle reflex. However, earlier studies have not provided unequivocal evidence for a potentiation of the startle reflex during tonic contact heat pain. The demonstration of modulating effects of pain on the startle reflex might require very intense tonic stimulation and investigation of subjects, who are particularly sensitive to startle potentiation by threatening cues. We investigated a sample of healthy subjects (N=20), who had shown pronounced startle amplitude potentiation in response to attack pictures. Noxious stimulation was provided by hand immersion into a hot water bath, which is a tonic pain model known for intense and summated stimulation. Modulation of the startle reflex was attempted by use of two stimulation intensities (42 °C, 46 °C) and one control condition (no stimulation). Even in these favorable conditions, we did not observe startle potentiation under painful stimulation in comparison to non-painful conditions although subjects reported to be experiencing moderate to high pain. Our findings indicate that tonic heat pain does not trigger defensive affective-motivational responses as measured by the startle reflex when it is applied in a predictable and thus non-threatening fashion. Future research should investigate the effects of manipulations of threat on startle responses to painful stimulation. Copyright © 2012 Elsevier B.V. All rights reserved.

  19. Animal models of pain and migraine in drug discovery

    DEFF Research Database (Denmark)

    Munro, Gordon; Jansen-Olesen, Inger; Olesen, Jes

    2017-01-01

    of the most commonly used models and methods employed within 'pain and migraine' drug development will be presented. Recent advances within these disciplines suggest that, with the addition of a few extra carefully chosen ancillary models and/or endpoints, the relative value in terms of resources used...

  20. The empathy impulse: A multinomial model of intentional and unintentional empathy for pain.

    Science.gov (United States)

    Cameron, C Daryl; Spring, Victoria L; Todd, Andrew R

    2017-04-01

    Empathy for pain is often described as automatic. Here, we used implicit measurement and multinomial modeling to formally quantify unintentional empathy for pain: empathy that occurs despite intentions to the contrary. We developed the pain identification task (PIT), a sequential priming task wherein participants judge the painfulness of target experiences while trying to avoid the influence of prime experiences. Using multinomial modeling, we distinguished 3 component processes underlying PIT performance: empathy toward target stimuli (Intentional Empathy), empathy toward prime stimuli (Unintentional Empathy), and bias to judge target stimuli as painful (Response Bias). In Experiment 1, imposing a fast (vs. slow) response deadline uniquely reduced Intentional Empathy. In Experiment 2, inducing imagine-self (vs. imagine-other) perspective-taking uniquely increased Unintentional Empathy. In Experiment 3, Intentional and Unintentional Empathy were stronger toward targets with typical (vs. atypical) pain outcomes, suggesting that outcome information matters and that effects on the PIT are not reducible to affective priming. Typicality of pain outcomes more weakly affected task performance when target stimuli were merely categorized rather than judged for painfulness, suggesting that effects on the latter are not reducible to semantic priming. In Experiment 4, Unintentional Empathy was stronger for participants who engaged in costly donation to cancer charities, but this parameter was also high for those who donated to an objectively worse but socially more popular charity, suggesting that overly high empathy may facilitate maladaptive altruism. Theoretical and practical applications of our modeling approach for understanding variation in empathy are discussed. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

  1. Personalized Pain Medicine: The Clinical Value of Psychophysical Assessment of Pain Modulation Profile

    Directory of Open Access Journals (Sweden)

    Yelena Granovsky

    2013-10-01

    Full Text Available Experimental pain stimuli can be used to simulate patients’ pain experience. We review recent developments in psychophysical pain testing, focusing on the application of the dynamic tests—conditioned pain modulation (CPM and temporal summation (TS. Typically, patients with clinical pain of various types express either less efficient CPM or enhanced TS, or both. These tests can be used in prediction of incidence of acquiring pain and of its intensity, as well as in assisting the correct choice of analgesic agents for individual patients. This can help to shorten the commonly occurring long and frustrating process of adjusting analgesic agents to the individual patients. We propose that evaluating pain modulation can serve as a step forward in individualizing pain medicine.

  2. A selective role for α3 subunit glycine receptors in inflammatory pain

    Directory of Open Access Journals (Sweden)

    Victoria L Harvey

    2009-11-01

    Full Text Available GlyR α3 has previously been found to play a critical role in pain hypersensitivity following spinal PGE2 injection, complete Freund’s adjuvant (CFA and zymosan induced peripheral inflammation. In this study, although all models displayed typical phenotypic behaviours, no significant differences were observed when comparing the pain behaviours of Glra3-/- and wild-type littermates following the injection of capsaicin, carrageenan, kaolin/ carrageenan or monosodium iodoacetate, models of rheumatoid and osteoarthritis, respectively. However, clear differences were observed following CFA injection (p < 0.01. No significant differences were observed in the pain behaviours of Glra3-/- and wild-type littermates following experimentally induced neuropathic pain (partial sciatic nerve ligation. Similarly, Glra3-/- and wild-type littermates displayed indistinguishable visceromotor responses to colorectal distension (a model of visceral pain and in vivo spinal cord dorsal horn electrophysiology revealed no differences in responses to multimodal suprathreshold stimuli, intensities which equate to higher pain scores such as those reported in the clinic. These data suggest that apart from its clear role in CFA- and zymosan-induced pain sensitisation, hypersensitivity associated with other models of inflammation, neuropathy and visceral disturbances involves mechanisms other than the EP2 receptor - GlyR α3 pathway.

  3. Social interaction and pain: An arctic expedition.

    Science.gov (United States)

    Block, Per; Heathcote, Lauren C; Burnett Heyes, Stephanie

    2018-01-01

    Complex human behaviour can only be understood within its social environment. However, disentangling the causal links between individual outcomes and social network position is empirically challenging. We present a research design in a closed real-world setting with high-resolution temporal data to understand this interplay within a fundamental human experience - physical pain. Study participants completed an isolated 3-week hiking expedition in the Arctic Circle during which they were subject to the same variation in environmental conditions and only interacted amongst themselves. Adolescents provided daily ratings of pain and social interaction partners. Using longitudinal network models, we analyze the interplay between social network position and the experience of pain. Specifically, we test whether experiencing pain is linked to decreasing popularity (increasing isolation), whether adolescents prefer to interact with others experiencing similar pain (homophily), and whether participants are increasingly likely to report similar pain as their interaction partners (contagion). We find that reporting pain is associated with decreasing popularity - interestingly, this effect holds for males only. Further exploratory analyses suggest this is at least partly driven by males withdrawing from contact with females when in pain, enhancing our understanding of pain and masculinity. Contrary to recent experimental and clinical studies, we found no evidence of pain homophily or contagion in the expedition group. Copyright © 2018 Elsevier Ltd. All rights reserved.

  4. Pain physiology education improves health status and endogenous pain inhibition in fibromyalgia: a double-blind randomized controlled trial.

    Science.gov (United States)

    Van Oosterwijck, Jessica; Meeus, Mira; Paul, Lorna; De Schryver, Mieke; Pascal, Aurelie; Lambrecht, Luc; Nijs, Jo

    2013-10-01

    There is evidence that education on pain physiology can have positive effects on pain, disability, and catastrophization in patients with chronic musculoskeletal pain disorders. A double-blind randomized controlled trial (RCT) was performed to examine whether intensive pain physiology education is also effective in fibromyalgia (FM) patients, and whether it is able to influence the impaired endogenous pain inhibition of these patients. Thirty FM patients were randomly allocated to either the experimental (receiving pain physiology education) or the control group (receiving pacing self-management education). The primary outcome was the efficacy of the pain inhibitory mechanisms, which was evaluated by spatially accumulating thermal nociceptive stimuli. Secondary outcome measures included pressure pain threshold measurements and questionnaires assessing pain cognitions, behavior, and health status. Assessments were performed at baseline, 2 weeks, and 3 months follow-up. Repeated measures ANOVAS were used to reveal possible therapy effects and effect sizes were calculated. After the intervention the experimental group had improved knowledge of pain neurophysiology (Pphysiology. Pain physiology education seems to be a useful component in the treatment of FM patients as it improves health status and endogenous pain inhibition in the long term.

  5. Remote Effects of Electromagnetic Millimeter Waves on Experimentally Induced Cold Pain: A Double-Blinded Crossover Investigation in Healthy Volunteers.

    Science.gov (United States)

    Partyla, Tomasz; Hacker, Henriette; Edinger, Hardy; Leutzow, Bianca; Lange, Joern; Usichenko, Taras

    2017-03-01

    The hypoalgesic effect of electromagnetic millimeter waves (MW) is well studied in animal model; however, the results of human research are controversial. The aim of this study was to evaluate the effects of various frequency ranges of MW on hypoalgesia using the cold pressor test (CPT). Experimental pain was induced using standardized CPT protocols in 20 healthy male volunteers. The skin of the lower part of sternum was exposed to MW with a frequency of 42.25 GHz (active generator); MW within 50-75 GHz frequency range (noise generator); or an inactive MW device (placebo generator) in a random crossover double-blinded manner. Pain threshold, measured using the CPT, was the primary outcome. Other CPT parameters, heart rate, blood pressure, incidence of subjective sensations (paresthesia) during exposure, as well as quality of volunteers' blinding were also recorded. The end points of the condition with exposure to 42.25 GHz, were compared with baseline; exposure to noise 50-75 GHz; and placebo generators. Pain threshold increased during exposure to the 42.25 GHz generator when compared with baseline: median difference (MD), 1.97 seconds (95% confidence interval [CI], 0.35-3.73) and noise generator: MD, 1.27 seconds (95% CI, 0.05-2.33) but not compared with the placebo generator. Time to onset of cold and increasing pain sensations as well as diastolic blood pressure increased under the exposure to the 42.25 GHz generator when compared with baseline and noise generator. Other outcome measures were comparable among the study conditions. We were able to partially confirm the previously suggested hypoalgesic effects of low-intensity electromagnetic MW. However, the effect was indistinguishable from the placebo condition in our investigation.

  6. Race effects on temporal summation to heat pain in youth.

    Science.gov (United States)

    Morris, Matthew C; Walker, Lynn; Bruehl, Stephen; Hellman, Natalie; Sherman, Amanda L; Rao, Uma

    2015-05-01

    Racial differences in pain responsiveness have been demonstrated in adults. However, it is unclear whether racial differences are also present in youth and whether they extend to experimental pain indices assessing temporal summation of second pain (TSSP). Temporal summation of second pain provides an index of pain sensitivity and may be especially relevant in determining risk for chronic pain. This study assessed pain tolerance and TSSP to evoked thermal pain in 78 healthy youth (age range, 10-17), 51% of whom were African American and 49% were non-Hispanic white. Multilevel models revealed within-individual increases in pain ratings during the temporal summation task in non-Hispanic white youth that were consistent with TSSP. Pain ratings did not change significantly during the temporal summation task in African-American youth. Baseline evoked pain ratings were significantly higher in African-American compared with non-Hispanic white youth. These findings suggest that enhanced responsiveness to evoked thermal pain in African Americans is present in adolescence but is unlikely to be related to elevated TSSP. These results may have implications for understanding racial differences in chronic pain experience in adulthood.

  7. Effect of sex in the MRMT-1 model of cancer-induced bone pain

    DEFF Research Database (Denmark)

    Falk, Sarah; Al-Dihaissy, Tamara; Mezzanotte, Laura

    2015-01-01

    An overwhelming amount of evidence demonstrates sex-induced variation in pain processing, and has thus increased the focus on sex as an essential parameter for optimization of in vivo models in pain research. Mammary cancer cells are often used to model metastatic bone pain in vivo......, and are commonly used in both males and females. Here we demonstrate that compared to male rats, female rats have an increased capacity for recovery following inoculation of MRMT-1 mammary cells, thus potentially causing a sex-dependent bias in interpretation of the data....

  8. Dynamic changes to the endocannabinoid system in models of chronic pain

    Science.gov (United States)

    Rani Sagar, Devi; Burston, James J.; Woodhams, Stephen G.; Chapman, Victoria

    2012-01-01

    The analgesic effects of cannabinoid ligands, mediated by CB1 receptors are well established. However, the side-effect profile of CB1 receptor ligands has necessitated the search for alternative cannabinoid-based approaches to analgesia. Herein, we review the current literature describing the impact of chronic pain states on the key components of the endocannabinoid receptor system, in terms of regionally restricted changes in receptor expression and levels of key metabolic enzymes that influence the local levels of the endocannabinoids. The evidence that spinal CB2 receptors have a novel role in the modulation of nociceptive processing in models of neuropathic pain, as well as in models of cancer pain and arthritis is discussed. Recent advances in our understanding of the spinal location of the key enzymes that regulate the levels of the endocannabinoid 2-AG are discussed alongside the outcomes of recent studies of the effects of inhibiting the catabolism of 2-AG in models of pain. The complexities of the enzymes capable of metabolizing both anandamide (AEA) and 2-AG have become increasingly apparent. More recently, it has come to light that some of the metabolites of AEA and 2-AG generated by cyclooxygenase-2, lipoxygenases and cytochrome P450 are biologically active and can either exacerbate or inhibit nociceptive signalling. PMID:23108548

  9. Radiation-induced relief of pain in an animal model with bone invasion from cancer

    International Nuclear Information System (INIS)

    Seong, J.; Kim, J.; Kim, K.H.; Kim, U.J.; Lee, B.W.

    2003-01-01

    In clinic, local radiation is effective for relief of pain from cancer invasion into the bones. This effect is usually observed before the regression of tumor occurs, which implies radiation-induced pain relief by mechanisms other than tumor irradication. In this study, possible mechanisms were explored in animal model system. To establish an animal model, syngeneic hepatocarcinoma, HCa-I was transplanted on femoral periosteum of C3H/HeJ male mice and bone-invasive tumor growth was identified through the histological analysis. Development of tumor-induced pain was assessed by von Frey filament test, acetone test, and radiant heat test. Animals were also irradiated for their tumors. Any change in pain was analyzed by above tests for the quantitative change and by immunohistochemical stain for the expression of molecules such as c-fos, substance P, and calcitonin gene-related peptide (CGRP) in lumbar spinal cord. Cancer invasion into the bone was started from 7th day after transplantation and became evident at day 14. Objective increase of pain in the ipsilateral thigh was observed at day 14 on von Frey filament test and acetone test, while there was no remarkable regression of the tumors. In this model system, local radiation of tumor resulted in decrease in objective pain on von Frey filament test and acetone test. In the immunohistochemical stain for lumbar spinal cord, the expression of substance P and CGRP but not c-fos increased in tumor-bearing animal compared to the control. The expression of these molecules decreased in animals given local radiation. In summary, an animal model system was established for objective pain from cancer invasion into the bones. Local radiation of tumor induced objective pain relief and this effect seems to be mediated not by tumor regression but through altered production of pain-related molecules

  10. Radiation-induced relief of pain in an animal model with bone invasion from cancer

    Energy Technology Data Exchange (ETDEWEB)

    Seong, J; Kim, J; Kim, K H; Kim, U J; Lee, B W [Yonsei University Medical College, (Korea, Republic of)

    2003-07-01

    In clinic, local radiation is effective for relief of pain from cancer invasion into the bones. This effect is usually observed before the regression of tumor occurs, which implies radiation-induced pain relief by mechanisms other than tumor irradication. In this study, possible mechanisms were explored in animal model system. To establish an animal model, syngeneic hepatocarcinoma, HCa-I was transplanted on femoral periosteum of C3H/HeJ male mice and bone-invasive tumor growth was identified through the histological analysis. Development of tumor-induced pain was assessed by von Frey filament test, acetone test, and radiant heat test. Animals were also irradiated for their tumors. Any change in pain was analyzed by above tests for the quantitative change and by immunohistochemical stain for the expression of molecules such as c-fos, substance P, and calcitonin gene-related peptide (CGRP) in lumbar spinal cord. Cancer invasion into the bone was started from 7th day after transplantation and became evident at day 14. Objective increase of pain in the ipsilateral thigh was observed at day 14 on von Frey filament test and acetone test, while there was no remarkable regression of the tumors. In this model system, local radiation of tumor resulted in decrease in objective pain on von Frey filament test and acetone test. In the immunohistochemical stain for lumbar spinal cord, the expression of substance P and CGRP but not c-fos increased in tumor-bearing animal compared to the control. The expression of these molecules decreased in animals given local radiation. In summary, an animal model system was established for objective pain from cancer invasion into the bones. Local radiation of tumor induced objective pain relief and this effect seems to be mediated not by tumor regression but through altered production of pain-related molecules.

  11. Neonatal Pain in Very Preterm Infants: Long-Term Effects on Brain, Neurodevelopment and Pain Reactivity

    Directory of Open Access Journals (Sweden)

    Ruth Eckstein Grunau

    2013-10-01

    Full Text Available Effects of early life psychosocial adversity have received a great deal of attention, such as maternal separation in experimental animal models and abuse/neglect in young humans. More recently, long-term effects of the physical stress of repetitive procedural pain have begun to be addressed in infants hospitalized in neonatal intensive care. Preterm infants are more sensitive to pain and stress, which cannot be distinguished in neonates. The focus of this review is clinical studies of long-term effects of repeated procedural pain-related stress in the neonatal intensive care unit (NICU in relation to brain development, neurodevelopment, programming of stress systems, and later pain sensitivity in infants born very preterm (24–32 weeks’ gestational age. Neonatal pain exposure has been quantified as the number of invasive and/or skin-breaking procedures during hospitalization in the NICU. Emerging studies provide convincing clinical evidence for an adverse impact of neonatal pain/stress in infants at a time of physiological immaturity, rapidly developing brain microstructure and networks, as well as programming of the hypothalamic-pituitary-adrenal axis. Currently it appears that early pain/stress may influence the developing brain and thereby neurodevelopment and stress-sensitive behaviors, particularly in the most immature neonates. However, there is no evidence for greater prevalence of pain syndromes compared to children and adults born healthy at full term. In addressing associations between pain/stress and outcomes, careful consideration of confounding clinical factors related to prematurity is essential. The need for pain management for humanitarian care is widely advocated. Non-pharmacological interventions to help parents reduce their infant’s stress may be brain-protective.

  12. Evaluation of pain management interventions for neonatal circumcision pain.

    Science.gov (United States)

    Joyce, B A; Keck, J F; Gerkensmeyer, J

    2001-01-01

    The purpose of the study was to determine the efficacy of music and eutectic mixture of local anesthetics (EMLA) on pain responses of neonates undergoing circumcision. A randomized, double-blind experimental design was used with 23 neonates. Pain response was measured using an observational pain intensity rating scale and the physiologic parameters of heart rate, respiratory rate, oxygen saturation levels, salivary cortisol levels, and length of cry. Each infant's state was examined for a potential contribution to the pain response. Infant state, salivary cortisol levels, and respiratory rates were not significant. Pain ratings had considerable variability for all treatment conditions, but both single treatment groups had less pain by the end of the procedure. The heart rate was significantly lower for the EMLA group and remained stable for the music group. Oxygen saturation differences were statistically significant for the music group (P =.02) and approached significance for the EMLA group. Preliminary support was provided for the efficacy of EMLA and music to contribute to the pain relief of neonates undergoing circumcision. Further study is warranted. Neonates deserve interventions that will provide them with a less painful start in life.

  13. Deep Multimodal Pain Recognition: A Database and Comparison of Spatio-Temporal Visual Modalities

    DEFF Research Database (Denmark)

    Haque, Mohammad Ahsanul; Nasrollahi, Kamal; Moeslund, Thomas B.

    2018-01-01

    , exploiting both spatial and temporal information of the face to assess pain level, and second, incorporating multiple visual modalities to capture complementary face information related to pain. Most works in the literature focus on merely exploiting spatial information on chromatic (RGB) video data......PAIN)' database, for RGBDT pain level recognition in sequences. We provide a first baseline results including 5 pain levels recognition by analyzing independent visual modalities and their fusion with CNN and LSTM models. From the experimental evaluation we observe that fusion of modalities helps to enhance...... recognition performance of pain levels in comparison to isolated ones. In particular, the combination of RGB, D, and T in an early fusion fashion achieved the best recognition rate....

  14. Influence of Polymorphisms in the HTR3A and HTR3B Genes on Experimental Pain and the Effect of the 5-HT3 Antagonist Granisetron.

    Science.gov (United States)

    Louca Jounger, Sofia; Christidis, Nikolaos; Hedenberg-Magnusson, Britt; List, Thomas; Svensson, Peter; Schalling, Martin; Ernberg, Malin

    2016-01-01

    The aim of this study was to investigate experimentally if 5-HT3 single nucleotide polymorphisms (SNP) contribute to pain perception and efficacy of the 5-HT3-antagonist granisetron and sex differences. Sixty healthy participants were genotyped regarding HTR3A (rs1062613) and HTR3B (rs1176744). First, pain was induced by bilateral hypertonic saline injections (HS, 5.5%, 0.2 mL) into the masseter muscles. Thirty min later the masseter muscle on one side was pretreated with 0.5 mL granisetron (1 mg/mL) and on the other side with 0.5 mL placebo (isotonic saline) followed by another HS injection (0.2 mL). Pain intensity, pain duration, pain area and pressure pain thresholds (PPTs) were assessed after each injection. HS evoked moderate pain, with higher intensity in the women (P = 0.023), but had no effect on PPTs. None of the SNPs influenced any pain variable in general, but compared to men, the pain area was larger in women carrying the C/C (HTR3A) (P = 0.015) and pain intensity higher in women with the A/C alleles (HTR3B) (P = 0.019). Pre-treatment with granisetron reduced pain intensity, duration and area to a lesser degree in women (P granisetron. Women carrying the C/T & T/T (HTR3A) genotype had less reduction of pain intensity (P = 0.041) and area (P = 0.005), and women with the C/C genotype (HTR3B) had less reduction of pain intensity (P = 0.030), duration (P = 0.030) and area compared to men (P = 0.017). In conclusion, SNPs did not influence experimental muscle pain or the effect of granisetron on pain variables in general, but there were some sex differences in pain variables that seem to be influenced by genotypes. However, due to the small sample size further research is needed before any firm conclusions can be drawn.

  15. Influence of Polymorphisms in the HTR3A and HTR3B Genes on Experimental Pain and the Effect of the 5-HT3 Antagonist Granisetron.

    Directory of Open Access Journals (Sweden)

    Sofia Louca Jounger

    Full Text Available The aim of this study was to investigate experimentally if 5-HT3 single nucleotide polymorphisms (SNP contribute to pain perception and efficacy of the 5-HT3-antagonist granisetron and sex differences. Sixty healthy participants were genotyped regarding HTR3A (rs1062613 and HTR3B (rs1176744. First, pain was induced by bilateral hypertonic saline injections (HS, 5.5%, 0.2 mL into the masseter muscles. Thirty min later the masseter muscle on one side was pretreated with 0.5 mL granisetron (1 mg/mL and on the other side with 0.5 mL placebo (isotonic saline followed by another HS injection (0.2 mL. Pain intensity, pain duration, pain area and pressure pain thresholds (PPTs were assessed after each injection. HS evoked moderate pain, with higher intensity in the women (P = 0.023, but had no effect on PPTs. None of the SNPs influenced any pain variable in general, but compared to men, the pain area was larger in women carrying the C/C (HTR3A (P = 0.015 and pain intensity higher in women with the A/C alleles (HTR3B (P = 0.019. Pre-treatment with granisetron reduced pain intensity, duration and area to a lesser degree in women (P < 0.05, but the SNPs did not in general influence the efficacy of granisetron. Women carrying the C/T & T/T (HTR3A genotype had less reduction of pain intensity (P = 0.041 and area (P = 0.005, and women with the C/C genotype (HTR3B had less reduction of pain intensity (P = 0.030, duration (P = 0.030 and area compared to men (P = 0.017. In conclusion, SNPs did not influence experimental muscle pain or the effect of granisetron on pain variables in general, but there were some sex differences in pain variables that seem to be influenced by genotypes. However, due to the small sample size further research is needed before any firm conclusions can be drawn.

  16. The role of state anxiety in children's memories for pain.

    Science.gov (United States)

    Noel, Melanie; Chambers, Christine T; McGrath, Patrick J; Klein, Raymond M; Stewart, Sherry H

    2012-06-01

    To investigate the impact of experimentally manipulated state anxiety and the influence of anxiety-related variables on children's memories for pain. A total of 110 children (60 boys) between the ages of 8 and 12 years were randomly assigned to complete a state anxiety induction task or a control task. Following experimental manipulation, children completed a laboratory pain task, pain ratings, and questionnaire measures of anxiety-related variables. 2 weeks later, children provided pain ratings based on their memories of the pain task. The experimental manipulation effectively induced state anxiety; however, pain memories did not differ between groups. Irrespective of group assignment, children with higher state anxiety had more negative pain memories. State anxiety uniquely predicted children's pain memories over and above other well established factors. Anxiety sensitivity and trait anxiety were significant predictors of recalled pain-related fear. These data highlight the importance of anxiety in the development of children's memories for pain.

  17. The Src family kinase inhibitor dasatinib delays pain-related behaviour and conserves bone in a rat model of cancer-induced bone pain

    DEFF Research Database (Denmark)

    Appel, Camilla Kristine; Gallego-Pedersen, Simone; Andersen, Line

    2017-01-01

    Pain is a severe and debilitating complication of metastatic bone cancer. Current analgesics do not provide sufficient pain relief for all patients, creating a great need for new treatment options. The Src kinase, a non-receptor protein tyrosine kinase, is implicated in processes involved in cancer......-induced bone pain, including cancer growth, osteoclastic bone degradation and nociceptive signalling. Here we investigate the role of dasatinib, an oral Src kinase family and Bcr-Abl tyrosine kinase inhibitor, in an animal model of cancer-induced bone pain. Daily administration of dasatinib (15 mg/kg, p...

  18. Sex differences in heritability of neck Pain

    DEFF Research Database (Denmark)

    Fejer, René; Hartvigsen, Jan; Kyvik, Kirsten Ohm

    2006-01-01

    Experimental studies have suggested biological factors as a possible explanation for gender disparities in perception of pain. Recently, heritability of liability to neck pain (NP) has been found to be statistically significantly larger in women compared to men. However, no studies have been...... conducted to determine whether the sex differences in heritability of NP are due to sex-specific genetic factors. Data on lifetime prevalence of NP from a population-based cross-sectional survey of 33,794 Danish twins were collected and age-stratified univariate biometrical modeling using sex......-limitation models was performed based on 10,605 dizygotic (DZ) twins of opposite sex to estimate the qualitative sex differences. In a full sex-limitation model the genetic component in females were higher than in males, but the genetic and the shared environmental correlations were equal to what is normally...

  19. Central Pain Processing in Early-Stage Parkinson's Disease: A Laser Pain fMRI Study.

    Directory of Open Access Journals (Sweden)

    Christine Petschow

    Full Text Available Pain is a common non-motor symptom in Parkinson's disease. As dopaminergic dysfunction is suggested to affect intrinsic nociceptive processing, this study was designed to characterize laser-induced pain processing in early-stage Parkinson's disease patients in the dopaminergic OFF state, using a multimodal experimental approach at behavioral, autonomic, imaging levels.13 right-handed early-stage Parkinson's disease patients without cognitive or sensory impairment were investigated OFF medication, along with 13 age-matched healthy control subjects. Measurements included warmth perception thresholds, heat pain thresholds, and central pain processing with event-related functional magnetic resonance imaging (erfMRI during laser-induced pain stimulation at lower (E = 440 mJ and higher (E = 640 mJ target energies. Additionally, electrodermal activity was characterized during delivery of 60 randomized pain stimuli ranging from 440 mJ to 640 mJ, along with evaluation of subjective pain ratings on a visual analogue scale.No significant differences in warmth perception thresholds, heat pain thresholds, electrodermal activity and subjective pain ratings were found between Parkinson's disease patients and controls, and erfMRI revealed a generally comparable activation pattern induced by laser-pain stimuli in brain areas belonging to the central pain matrix. However, relatively reduced deactivation was found in Parkinson's disease patients in posterior regions of the default mode network, notably the precuneus and the posterior cingulate cortex.Our data during pain processing extend previous findings suggesting default mode network dysfunction in Parkinson's disease. On the other hand, they argue against a genuine pain-specific processing abnormality in early-stage Parkinson's disease. Future studies are now required using similar multimodal experimental designs to examine pain processing in more advanced stages of Parkinson's disease.

  20. Thresholds and perception of cold pain, heat pain, and the thermal grill illusion in patients with major depressive disorder.

    Science.gov (United States)

    Boettger, Michael Karl; Grossmann, David; Bär, Karl-Jürgen

    2013-04-01

    The thermal grill illusion (TGI) in which interlacing cold and warm bars create the illusion of a painful sensation has been suggested as an experimental model for central pain states and pain processing. The aim of this study was to use this technique to gain further insights into the altered pain perception in major depressive disorder (MDD). In 18 unmedicated patients with MDD, cold and heat pain thresholds (CPT/HPT) as well as the perception of the TGI were examined and compared with 18 matched controls. CPT and HPT were significantly increased in patients (7.9°C and 47.5°C) compared with controls (15.9°C and 45.2°C, respectively; p painful by controls, the patients did not indicate painful sensations, thereby indicating a shift of the stimulus-response curve of TGI pain perception toward higher stimulus intensities, that is, greater temperature differentials between cold and warm bars (11.5°C for controls, 16.7°C for patients). The patients rated the pain intensity perceived at the respective pain thresholds (CPT and HPT) in tendency higher than did the controls, whereas they perceived the TGI less painful despite increased stimulus intensities. Unpleasantness ratings were similar between groups. CPT, HPT and temperature differentials for the perception of the TGI, were increased in patients with MDD as compared with controls. Pain intensity, however, was rated differently for CPT and HPT, where patients indicated higher ratings in tendency, and for the TGI stimulation, where pain was perceived less intense.

  1. Cost-effectiveness modeling for neuropathic pain treatments: investigating the relative importance of parameters using an open-source model.

    Science.gov (United States)

    Hirst, Matthew; Bending, Matthew W; Baio, Gianluca; Yesufu-Udechuku, Amina; Dunlop, William C N

    2018-06-08

    The study objective was to develop an open-source replicate of a cost-effectiveness model developed by National Institute for Health and Care (NICE) in order to explore uncertainties in health economic modeling of novel pharmacological neuropathic pain treatments. The NICE model, consisting of a decision tree with branches for discrete levels of pain relief and adverse event (AE) severities, was replicated using R and used to compare a hypothetical neuropathic pain drug to pregabalin. Model parameters were sourced from NICE's clinical guidelines and associated with probability distributions to account for underlying uncertainty. A simulation-based scenario analysis was conducted to assess how uncertainty in efficacy and AEs affected the net monetary benefit (NMB) for the hypothetical treatment at a cost-effectiveness threshold of £20,000 per QALY. Relative to pregabalin, an increase in efficacy was associated with greater NMB than an improvement in tolerability. A greater NMB was observed when efficacy was marginally higher than that of pregabalin while maintaining the same level of AEs than when efficacy was equivalent to pregabalin but with a more substantial reduction in AEs. In the latter scenario, the NMB was only positive at a low cost-effectiveness threshold. The replicate model shares the limitations described in the NICE guidelines. There is a lack of support in scientific literature for the assumption that increased efficacy is associated with a greater reduction in tolerability. The replicate model also included a single comparator, unlike the NICE model. Pain relief is a stronger driver of NMB than tolerability at a cost-effectiveness threshold of £20,000 per QALY. Health technology assessment decisions which are influenced by NICE's model may reward efficacy gains even if they are associated with more severe AEs. This contrasts with recommendations from clinical guidelines for neuropathic pain which place more equal weighting on improvements in

  2. Antinociception induced by atorvastatin in different pain models.

    Science.gov (United States)

    Garcia, G G; Miranda, H F; Noriega, V; Sierralta, F; Olavarría, L; Zepeda, R J; Prieto, J C

    2011-11-01

    Atorvastatin is a statin that inhibits the 3-hydroxy-methyl-glutaryl coenzyme A (HMG-CoA) reductase. Several landmark clinical trials have demonstrated the beneficial effects of statin therapy for primary and secondary prevention of cardiovascular disease. It is assumed that the beneficial effects of statin therapy are entirely due to cholesterol reduction. Statins have an additional activity (pleiotropic effect) that has been associated to their anti-inflammatory effects. The aim of the present study was to assess the antinociceptive activity of atorvastatin in five animal pain models. The daily administration of 3-100mg/kg of atorvastatin by oral gavage induced a significant dose-dependent antinociception in the writhing, tail-flick, orofacial formalin and formalin hind paw tests. However, this antinociceptive activity of atorvastatin was detectable only at high concentrations in the hot plate assay. The data obtained in the present study demonstrates the effect of atorvastatin to reduce nociception and inflammation in different animal pain models. Copyright © 2011 Elsevier Inc. All rights reserved.

  3. Hormones in pain modulation and their clinical implications for pain control: a critical review.

    Science.gov (United States)

    Chen, Xueyin; Zhang, Jinyuan; Wang, Xiangrui

    2016-07-01

    Recently, more and more studies have found that pain generation, transmission and modulation are under hormonal regulation. Indeed, hormonal dysregulation is a common component of chronic pain syndromes. Studies have attempted to determine whether the relationship between the pain and its perception and hormones is a causative relationship and how these processes interrelate. This review summarizes and analyzes the current experimental data and provides an overview of the studies addressing these questions. The relationship between pain perception and endocrine effects suggests that hormones can be used as important biomarkers of chronic pain syndromes and/or be developed into therapeutic agents in the fight against pain.

  4. The clinical application of fMRI data in a single-patient diagnostic conundrum: Classifying brain response to experimental pain to distinguish between gastrointestinal, depressive and eating disorder symptoms.

    Science.gov (United States)

    Strigo, Irina A; Murray, Stuart B; Simmons, Alan N; Bernard, Rebecca S; Huang, Jeannie S; Kaye, Walter H

    2017-11-01

    Patients with eating disorders (EDs) often present with psychiatric comorbidity, and functional and/or organic gastrointestinal (GI) symptomatology. Such multidiagnostic presentations can complicate diagnostic practice and treatment delivery. Here we describe an adolescent patient who presented with mixed ED, depressive, and GI symptomatology, who had received multiple contrasting diagnoses throughout treatment. We used a novel machine learning approach to classify (i) the patient's functional brain imaging during an experimental pain paradigm, and (ii) patient self-report psychological measures, to categorize the diagnostic phenotype most closely approximated by the patient. Specifically, we found that the patient's response to pain anticipation and experience within the insula and anterior cingulate cortices, and patient self-report data, were most consistent with patients with GI pain. This work is the first to demonstrate the possibility of using imaging data, alongside supervised learning models, for purposes of single patient classification in those with ED symptomatology, where diagnostic comorbidity is common. Copyright © 2017 Elsevier Ltd. All rights reserved.

  5. Ionic mechanisms in peripheral pain.

    Science.gov (United States)

    Fransén, Erik

    2014-01-01

    Chronic pain constitutes an important and growing problem in society with large unmet needs with respect to treatment and clear implications for quality of life. Computational modeling is used to complement experimental studies to elucidate mechanisms involved in pain states. Models representing the peripheral nerve ending often address questions related to sensitization or reduction in pain detection threshold. In models of the axon or the cell body of the unmyelinated C-fiber, a large body of work concerns the role of particular sodium channels and mutations of these. Furthermore, in central structures: spinal cord or higher structures, sensitization often refers not only to enhanced synaptic efficacy but also to elevated intrinsic neuronal excitability. One of the recent developments in computational neuroscience is the emergence of computational neuropharmacology. In this area, computational modeling is used to study mechanisms of pathology with the objective of finding the means of restoring healthy function. This research has received increased attention from the pharmaceutical industry as ion channels have gained increased interest as drug targets. Computational modeling has several advantages, notably the ability to provide mechanistic links between molecular and cellular levels on the one hand and functions at the systems level on the other hand. These characteristics make computational modeling an additional tool to be used in the process of selecting pharmaceutical targets. Furthermore, large-scale simulations can provide a framework to systematically study the effects of several interacting disease parameters or effects from combinations of drugs. © 2014 Elsevier Inc. All rights reserved.

  6. Synthesis and Analgesic Effects of μ-TRTX-Hhn1b on Models of Inflammatory and Neuropathic Pain

    Directory of Open Access Journals (Sweden)

    Yu Liu

    2014-08-01

    Full Text Available μ-TRTX-Hhn1b (HNTX-IV is a 35-amino acid peptide isolated from the venom of the spider, Ornithoctonus hainana. It inhibits voltage-gated sodium channel Nav1.7, which has been considered as a therapeutic target for pain. The goal of the present study is to elucidate the analgesic effects of synthetic μ-TRTX-Hhn1b on animal models of pain. The peptide was first synthesized and then successfully refolded/oxidized. The synthetic peptide had the same inhibitory effect on human Nav1.7 current transiently expressed in HEK 293 cells as the native toxin. Furthermore, the analgesic potentials of the synthetic peptide were examined on models of inflammatory pain and neuropathic pain. μ-TRTX-Hhn1b produced an efficient reversal of acute nociceptive pain in the abdominal constriction model, and significantly reduced the pain scores over the 40-min period in the formalin model. The efficiency of μ-TRTX-Hhn1b on both models was equivalent to that of morphine. In the spinal nerve model, the reversal effect of μ-TRTX-Hhn1b on allodynia was longer and higher than mexiletine. These results demonstrated that μ-TRTX-Hhn1b efficiently alleviated acute inflammatory pain and chronic neuropathic pain in animals and provided an attractive template for further clinical analgesic drug design.

  7. Morphine- and buprenorphine-induced analgesia and antihyperalgesia in a human inflammatory pain model

    DEFF Research Database (Denmark)

    Ravn, Pernille; Secher, EL; Skram, U

    2013-01-01

    Opioid therapy is associated with the development of tolerance and paradoxically increased sensitivity to pain. It has been suggested that buprenorphine is associated with a higher antihyperalgesia/analgesia ratio than μ-opioid receptor agonists. The primary outcome of this study was therefore...... to investigate relative differences in antihyperalgesia and analgesia effects between morphine and buprenorphine in an inflammatory pain model in volunteers. The secondary outcome was to examine the relationship between pain sensitivity and opioid-induced effects on analgesia, antihyperalgesia, and descending...... pain modulation....

  8. A mouse model for chronic pain-induced increase in ethanol consumption.

    Science.gov (United States)

    Butler, Ryan K; Knapp, Darin J; Ulici, Veronica; Longobardi, Lara; Loeser, Richard F; Breese, George R

    2017-03-01

    Chronic pain conditions are often comorbid with alcohol abuse. "Self-medication" with alcohol introduces a host of problems associated with the abuse of alcohol which over time has the potential of exacerbating the painful condition. Despite the prevalence of chronic pain being associated with alcohol abuse, rodent models which mimic the comorbid conditions are lacking. In this study, we model osteoarthritis (OA) in C57BL/6J mice by surgically destabilizing the medial meniscus (DMM). Sham-operated mice served as controls. Thirteen weeks after surgery, DMM but not sham-operated mice exhibited pronounced incapacitance of the surgically manipulated hind limb compared with the nonsurgically manipulated hind limb. At this time, the mice were exposed to the 2-bottle ethanol choice, beginning with 2.5% with a gradual increasing to 20%. Compared with sham controls, DMM mice consumed more EtOH and preferred EtOH over water at the 20% EtOH concentration. Histological analysis verified that the DMM mice exhibited significant damage to the articular cartilage and osteophyte growth compared with sham controls and these measures of the severity of OA correlated with the amount of ethanol intake. Thus, the combination of the DMM model of OA with the enhanced two-bottle ethanol choice is a potential preclinical approach in mice by which the basis of the comorbid association of alcohol abuse and chronic pain conditions can be explored.

  9. Experimental muscle pain produces central modulation of proprioceptive signals arising from jaw muscle spindles.

    Science.gov (United States)

    Capra, N F; Ro, J Y

    2000-05-01

    The aim of the present study was to investigate the effects of intramuscular injection with hypertonic saline, a well-established experimental model for muscle pain, on central processing of proprioceptive input from jaw muscle spindle afferents. Fifty-seven cells were recorded from the medial edge of the subnucleus interpolaris (Vi) and the adjacent parvicellular reticular formation from 11 adult cats. These cells were characterized as central units receiving jaw muscle spindle input based on their responses to electrical stimulation of the masseter nerve, muscle palpation and jaw stretch. Forty-five cells, which were successfully tested with 5% hypertonic saline, were categorized as either dynamic-static (DS) (n=25) or static (S) (n=20) neurons based on their responses to different speeds and amplitudes of jaw movement. Seventy-six percent of the cells tested with an ipsilateral injection of hypertonic saline showed a significant modulation of mean firing rates (MFRs) during opening and/or holding phases. The most remarkable saline-induced change was a significant reduction of MFR during the hold phase in S units (100%, 18/18 modulated). Sixty-nine percent of the DS units (11/16 modulated) also showed significant changes in MFRs limited to the hold phase. However, in the DS neurons, the MFRs increased in seven units and decreased in four units. Finally, five DS neurons showed significant changes of MFRs during both opening and holding phases. Injections of isotonic saline into the ipsilateral masseter muscle had little effect, but hypertonic saline injections made into the contralateral masseter muscle produced similar results to ipsilateral injections with hypertonic saline. These results unequivocally demonstrate that intramuscular injection with an algesic substance, sufficient to produce muscle pain, produces significant changes in the proprioceptive properties of the jaw movement-related neurons. Potential mechanisms involved in saline-induced changes in the

  10. High-frequency electroacupuncture versus carprofen in an incisional pain model in rats

    Directory of Open Access Journals (Sweden)

    F.M. Teixeira

    2012-12-01

    Full Text Available The objective of the present study was to compare the effect of electroacupuncture (EA and carprofen (CP on postoperative incisional pain using the plantar incision (PI model in rats. A 1-cm longitudinal incision was made through skin, fascia and muscles of a hind paw of male Wistar rats and the development of mechanical and thermal hypersensitivity was determined over 4 days using the von Frey and Hargreaves methods, respectively. Based on the experimental treatments received on the third postoperative day, the animals were divided into the following groups: PI+CP (CP, 2 mg/kg, po; PI+EAST36 (100-Hz EA applied bilaterally at the Zusanli point (ST36; PI+EANP (EA applied to a non-acupoint region; PI+IMMO (immobilization only; PI (vehicle. In the von Frey test, the PI+EAST36 group had higher withdrawal force thresholds in response to mechanical stimuli than the PI, PI+IMMO and PI+EANP groups at several times studied. Furthermore, the PI+EAST36 group showed paw withdrawal thresholds in response to mechanical stimuli that were similar to those of the PI+CP group. In the Hargreaves test, all groups had latencies higher than those observed with PI. The PI+EAST36 group was similar to the PI+IMMO, PI+EANP and PI+CP groups. We conclude that 100-Hz EA at the ST36 point, but not at non-acupoints, can reduce mechanical nociception in the rat model of incisional pain, and its effectiveness is comparable to that of carprofen.

  11. High-frequency electroacupuncture versus carprofen in an incisional pain model in rats

    International Nuclear Information System (INIS)

    Teixeira, F.M.; Castro, L.L.; Ferreira, R.T.; Pires, P.A.; Vanderlinde, F.A.; Medeiros, M.A.

    2012-01-01

    The objective of the present study was to compare the effect of electroacupuncture (EA) and carprofen (CP) on postoperative incisional pain using the plantar incision (PI) model in rats. A 1-cm longitudinal incision was made through skin, fascia and muscles of a hind paw of male Wistar rats and the development of mechanical and thermal hypersensitivity was determined over 4 days using the von Frey and Hargreaves methods, respectively. Based on the experimental treatments received on the third postoperative day, the animals were divided into the following groups: PI+CP (CP, 2 mg/kg, po); PI+EAST36 (100-Hz EA applied bilaterally at the Zusanli point (ST36)); PI+EANP (EA applied to a non-acupoint region); PI+IMMO (immobilization only); PI (vehicle). In the von Frey test, the PI+EAST36 group had higher withdrawal force thresholds in response to mechanical stimuli than the PI, PI+IMMO and PI+EANP groups at several times studied. Furthermore, the PI+EAST36 group showed paw withdrawal thresholds in response to mechanical stimuli that were similar to those of the PI+CP group. In the Hargreaves test, all groups had latencies higher than those observed with PI. The PI+EAST36 group was similar to the PI+IMMO, PI+EANP and PI+CP groups. We conclude that 100-Hz EA at the ST36 point, but not at non-acupoints, can reduce mechanical nociception in the rat model of incisional pain, and its effectiveness is comparable to that of carprofen

  12. High-frequency electroacupuncture versus carprofen in an incisional pain model in rats.

    Science.gov (United States)

    Teixeira, F M; Castro, L L; Ferreira, R T; Pires, P A; Vanderlinde, F A; Medeiros, M A

    2012-12-01

    The objective of the present study was to compare the effect of electroacupuncture (EA) and carprofen (CP) on postoperative incisional pain using the plantar incision (PI) model in rats. A 1-cm longitudinal incision was made through skin, fascia and muscles of a hind paw of male Wistar rats and the development of mechanical and thermal hypersensitivity was determined over 4 days using the von Frey and Hargreaves methods, respectively. Based on the experimental treatments received on the third postoperative day, the animals were divided into the following groups: PI+CP (CP, 2 mg/kg, po); PI+EAST36 (100-Hz EA applied bilaterally at the Zusanli point (ST36)); PI+EANP (EA applied to a non-acupoint region); PI+IMMO (immobilization only); PI (vehicle). In the von Frey test, the PI+EAST36 group had higher withdrawal force thresholds in response to mechanical stimuli than the PI, PI+IMMO and PI+EANP groups at several times studied. Furthermore, the PI+EAST36 group showed paw withdrawal thresholds in response to mechanical stimuli that were similar to those of the PI+CP group. In the Hargreaves test, all groups had latencies higher than those observed with PI. The PI+EAST36 group was similar to the PI+IMMO, PI+EANP and PI+CP groups. We conclude that 100-Hz EA at the ST36 point, but not at non-acupoints, can reduce mechanical nociception in the rat model of incisional pain, and its effectiveness is comparable to that of carprofen.

  13. High-frequency electroacupuncture versus carprofen in an incisional pain model in rats

    Energy Technology Data Exchange (ETDEWEB)

    Teixeira, F.M.; Castro, L.L.; Ferreira, R.T.; Pires, P.A.; Vanderlinde, F.A.; Medeiros, M.A. [Departamento de Ciências Fisiológicas, Universidade Federal Rural do Rio de Janeiro, Rio de Janeiro, RJ (Brazil)

    2012-08-24

    The objective of the present study was to compare the effect of electroacupuncture (EA) and carprofen (CP) on postoperative incisional pain using the plantar incision (PI) model in rats. A 1-cm longitudinal incision was made through skin, fascia and muscles of a hind paw of male Wistar rats and the development of mechanical and thermal hypersensitivity was determined over 4 days using the von Frey and Hargreaves methods, respectively. Based on the experimental treatments received on the third postoperative day, the animals were divided into the following groups: PI+CP (CP, 2 mg/kg, po); PI+EAST36 (100-Hz EA applied bilaterally at the Zusanli point (ST36)); PI+EANP (EA applied to a non-acupoint region); PI+IMMO (immobilization only); PI (vehicle). In the von Frey test, the PI+EAST36 group had higher withdrawal force thresholds in response to mechanical stimuli than the PI, PI+IMMO and PI+EANP groups at several times studied. Furthermore, the PI+EAST36 group showed paw withdrawal thresholds in response to mechanical stimuli that were similar to those of the PI+CP group. In the Hargreaves test, all groups had latencies higher than those observed with PI. The PI+EAST36 group was similar to the PI+IMMO, PI+EANP and PI+CP groups. We conclude that 100-Hz EA at the ST36 point, but not at non-acupoints, can reduce mechanical nociception in the rat model of incisional pain, and its effectiveness is comparable to that of carprofen.

  14. Behavioral, medical imaging and histopathological features of a new rat model of bone cancer pain.

    Directory of Open Access Journals (Sweden)

    Louis Doré-Savard

    2010-10-01

    Full Text Available Pre-clinical bone cancer pain models mimicking the human condition are required to respond to clinical realities. Breast or prostate cancer patients coping with bone metastases experience intractable pain, which affects their quality of life. Advanced monitoring is thus required to clarify bone cancer pain mechanisms and refine treatments. In our model of rat femoral mammary carcinoma MRMT-1 cell implantation, pain onset and tumor growth were monitored for 21 days. The surgical procedure performed without arthrotomy allowed recording of incidental pain in free-moving rats. Along with the gradual development of mechanical allodynia and hyperalgesia, behavioral signs of ambulatory pain were detected at day 14 by using a dynamic weight-bearing apparatus. Osteopenia was revealed from day 14 concomitantly with disorganization of the trabecular architecture (µCT. Bone metastases were visualized as early as day 8 by MRI (T(1-Gd-DTPA before pain detection. PET (Na(18F co-registration revealed intra-osseous activity, as determined by anatomical superimposition over MRI in accordance with osteoclastic hyperactivity (TRAP staining. Pain and bone destruction were aggravated with time. Bone remodeling was accompanied by c-Fos (spinal and ATF3 (DRG neuronal activation, sustained by astrocyte (GFAP and microglia (Iba1 reactivity in lumbar spinal cord. Our animal model demonstrates the importance of simultaneously recording pain and tumor progression and will allow us to better characterize therapeutic strategies in the future.

  15. Internal and external factors affecting the development of neuropathic pain in rodents. Is it all about pain?

    Science.gov (United States)

    Vissers, K; De Jongh, R; Hoffmann, V; Heylen, R; Crul, B; Meert, T

    2003-12-01

    It is important to know the factors that will influence animal models of neuropathic pain. A good reproducibility and predictability in different strains of animals for a given test increases the clinical relevance and possible targeting. An obligatory requirement for enabling comparisons of results of different origin is a meticulous definition of the specific sensitivities of a model for neuropathic pain and a description of the test conditions. Factors influencing neuropathic pain behavior can be subdivided in external and internal factors. The most important external factors are; timing of the measurement of pain after induction of neuropathy, circadian rhythms, seasonal influences, air humidity, influence of order of testing, diet, social variables, housing and manipulation, cage density, sexual activity, external stress factors, and influences of the experimenter. The internal factors are related to the type of animal, its genetic background, gender, age, and the presence of homeostatic adaptation mechanisms to specific situations or stress. In practice, the behavioral presentations to pain depend on the combination of genetic and environmental factors such as accepted social behavior. It also depends on the use of genetic manipulation of the animals such as in transgenic animals. These make the interpretation of data even more difficult. Differences of pain behavior between in- and outbred animals will be better understood by using modern analysis techniques. Substrains of animals with a high likelihood for developing neuropathic pain make the unraveling of specific pathophysiological mechanisms possible. Concerning the effect of stress on pain, it is important to differentiate between external and internal stress such as social coping behavior. The individual dealing with this stress is species sensitive, and depends on the genotype and the social learning. In the future, histo-immunological and genetic analysis will highlight similarities of the different

  16. The β-lactam clavulanic acid mediates glutamate transport-sensitive pain relief in a rat model of neuropathic pain

    DEFF Research Database (Denmark)

    Kristensen, P J; Gegelashvili, G; Munro, G

    2017-01-01

    -regulates glutamate transporters both in vitro and in vivo. Crucially, a similar up-regulation of glutamate transporters in human spinal astrocytes by clavulanic acid supports the development of novel β-lactam-based analgesics, devoid of antibacterial activity, for the clinical treatment of chronic pain.......BACKGROUND: Following nerve injury, down-regulation of astroglial glutamate transporters (GluTs) with subsequent extracellular glutamate accumulation is a key factor contributing to hyperexcitability within the spinal dorsal horn. Some β-lactam antibiotics can up-regulate GluTs, one of which......, ceftriaxone, displays analgesic effects in rodent chronic pain models. METHODS: Here, the antinociceptive actions of another β-lactam clavulanic acid, which possesses negligible antibiotic activity, were compared with ceftriaxone in rats with chronic constriction injury (CCI)-induced neuropathic pain...

  17. Cancer Pain Management Education Rectifies Patients' Misconceptions of Cancer Pain, Reduces Pain, and Improves Quality of Life.

    Science.gov (United States)

    Koh, Su-Jin; Keam, Bhumsuk; Hyun, Min Kyung; Ju Seo, Jeong; Uk Park, Keon; Oh, Sung Yong; Ahn, Jinseok; Lee, Ja Youn; Kim, JinShil

    2018-03-26

    More than half of the patients have reported improper management of breakthrough cancer pain. Empirical evidence is lacking concerning the effectiveness of cancer pain education on breakthrough pain control. This study aimed to examine the effects of individual pain education on pain control, use of short-acting analgesics for breakthrough pain, quality of life outcomes, and rectification of patients' misconceptions regarding cancer pain. A quasi-experimental design was used. In total, 176 (102 inpatients and 74 outpatients) and 163 (93 inpatients and 70 outpatients) cancer patients completed questionnaires on pain intensity, quality of life, use of short-acting medication for breakthrough pain, and misconceptions about cancer pain and opioid use before and immediately and/or seven days after individual pain education. The mean age of the participants was 60.9 years (±11.2), and 56.3% were male. The most common cancers were lung cancer (17.0%), colon cancer (15.9%), and breast cancer (12.5%). The subjects' reasons for attrition were conditional deterioration, death, or voluntary withdrawal (N = 13, 7.4%). Following the education, there was a significant reduction in overall pain intensity over 24 hours (P < 0.001). The outpatients showed more use of short-acting analgesics for breakthrough pain. Sleep quality change was most significantly associated with intervention; other quality of life aspects (e.g., general feelings and life enjoyment) also improved. Pain education also significantly reduced misconceptions regarding cancer pain management. The present educational intervention was effective in encouraging short-acting analgesic use for breakthrough pain, improving quality of life outcomes, and rectifying patients' misconceptions about analgesic use.

  18. Pain, pain intensity and pain disability in high school students are differently associated with physical activity, screening hours and sleep.

    Science.gov (United States)

    Silva, Anabela G; Sa-Couto, Pedro; Queirós, Alexandra; Neto, Maritza; Rocha, Nelson P

    2017-05-16

    Studies exploring the association between physical activity, screen time and sleep and pain usually focus on a limited number of painful body sites. Nevertheless, pain at different body sites is likely to be of different nature. Therefore, this study aims to explore and compare the association between time spent in self-reported physical activity, in screen based activities and sleeping and i) pain presence in the last 7-days for 9 different body sites; ii) pain intensity at 9 different body sites and iii) global disability. Nine hundred sixty nine students completed a questionnaire on pain, time spent in moderate and vigorous physical activity, screen based time watching TV/DVD, playing, using mobile phones and computers and sleeping hours. Univariate and multivariate associations between pain presence, pain intensity and disability and physical activity, screen based time and sleeping hours were investigated. Pain presence: sleeping remained in the multivariable model for the neck, mid back, wrists, knees and ankles/feet (OR 1.17 to 2.11); moderate physical activity remained in the multivariate model for the neck, shoulders, wrists, hips and ankles/feet (OR 1.06 to 1.08); vigorous physical activity remained in the multivariate model for mid back, knees and ankles/feet (OR 1.05 to 1.09) and screen time remained in the multivariate model for the low back (OR = 2.34. Pain intensity: screen time and moderate physical activity remained in the multivariable model for pain intensity at the neck, mid back, low back, shoulder, knees and ankles/feet (Rp 2 0.02 to 0.04) and at the wrists (Rp 2  = 0.04), respectively. Disability showed no association with sleeping, screen time or physical activity. This study suggests both similarities and differences in the patterns of association between time spent in physical activity, sleeping and in screen based activities and pain presence at 8 different body sites. In addition, they also suggest that the factors associated

  19. Effect of static magnetic field on pain level and expression of P2X3 receptors in the trigeminal ganglion in mice following experimental tooth movement.

    Science.gov (United States)

    Zhu, Yafen; Wang, Shengguo; Long, Hu; Zhu, Jingyi; Jian, Fan; Ye, Niansong; Lai, Wenli

    2017-01-01

    Recent research has demonstrated that static magnetic fields (SMF) can generate an analgesic effect in different conditions. The present study explored effects of SMF on pain levels and expressions of P2X3 receptors in trigeminal ganglion (TG) in mice after experimental tooth movement (tooth movement induced by springs between teeth). Experiments were performed in male mice (body mass: 25-30 g) and divided into SMF + force group, force group, and no force group. Exposure time was over 22 h per day. Mouse Grimace Scale was used for evaluating orofacial pain levels during experimental tooth movement at 4 h and 1, 3, 7, and 14 days. Meanwhile, expression levels of P2X3 receptors in the TG were evaluated by immunohistochemistry and western blotting at same time points. We finally found that during experimental tooth movement, pain levels of mice peaked at 3 days, and then decreased. While pain levels of mice were reduced in the SMF environment at 4 h, 1 and 3 days, there was a significant difference at 1 and 3 days. Meanwhile, under the action of SMF, expression levels of P2X3 receptors in TG were significantly lower at 4 h, 3 and 7 days. These results suggest that SMF can reduce pain levels in mice, and down-regulate P2X3 receptors in TG. Bioelectromagnetics. 38:22-30, 2017. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

  20. Spontaneous behavioral responses in the orofacial region: A model of trigeminal pain in mouse

    Science.gov (United States)

    Romero-Reyes, Marcela; Akerman, Simon; Nguyen, Elaine; Vijjeswarapu, Alice; Hom, Betty; Dong, Hong-Wei; Charles, Andrew C.

    2012-01-01

    OBJECTIVES To develop a translational mouse model for the study and measurement of non-evoked pain in the orofacial region by establishing markers of nociceptive-specific grooming behaviors in the mouse. BACKGROUND Some of the most prevalent and debilitating conditions involve pain in the trigeminal distribution. Although there are current therapies for these pain conditions, for many patients they are far from optimal. Understanding the pathophysiology of pain disorders arising from structures innervated by the trigeminal nerve is still limited and most animal behavioral models focus on the measurement of evoked pain. In patients, spontaneous (non-evoked) pain responses provide a more accurate representation of the pain experience than do responses that are evoked by an artificial stimulus. Therefore, the development of animal models that measure spontaneous nociceptive behaviors may provide a significant translational tool for a better understanding of pain neurobiology. METHODS C57BL/6 mice received either an injection of 0.9% Saline solution or complete Freund’s adjuvant (CFA) into the right masseter muscle. Animals were video recorded and then analyzed by an observer blind to the experiment group. The duration of different facial grooming patterns performed in the area of injection were measured. After 2 hrs, mice were euthanized, perfused and the brainstem was removed. Fos protein expression in the trigeminal nucleus caudalis was quantified using immunohistochemistry to investigate nociceptive-specific neuronal activation. A separate group of animals was treated with morphine sulfate, to determine the nociceptive-specific nature of their behaviors. RESULTS We characterized and quantified 3 distinct patterns of acute grooming behaviors: fore-paw rubbing, lower lip skin/cheek rubbing against enclosure floor and hind paw scratching. These behaviors occurred with a reproducible frequency and time course, and were inhibited by the analgesic morphine. CFA

  1. Different pain responses to chronic and acute pain in various ethnic/racial groups.

    Science.gov (United States)

    Rahavard, Behnoosh B; Candido, Kenneth D; Knezevic, Nebojsa Nick

    2017-09-01

    Our goal in this study was to review the similarities and differences among ethnic groups and their respective responses to acute and chronic clinically related and experimentally induced pain. In this review, the PUBMED and Google-Scholar databases were searched to analyze articles that have assessed the variations in both acute and chronic pain responses among different ethnic/racial groups. According to the results from 42 reviewed articles, significant differences exist among ethnic-racial groups for pain prevalence as well as responses to acute and chronic pain. Compared with Caucasians, other ethnic groups are more susceptible to acute pain responses to nociceptive stimulation and to the development of long-term chronic pain. These differences need to be addressed and assessed more extensively in the future in order to minimize the pain management disparities among various ethnic-racial groups and also to improve the relationship between pain management providers and their patients.

  2. Making Sense of Low Back Pain and Pain-Related Fear.

    Science.gov (United States)

    Bunzli, Samantha; Smith, Anne; Schütze, Robert; Lin, Ivan; O'Sullivan, Peter

    2017-09-01

    Synopsis Pain-related fear is implicated in the transition from acute to chronic low back pain and the persistence of disabling low back pain, making it a key target for physical therapy intervention. The current understanding of pain-related fear is that it is a psychopathological problem, whereby people who catastrophize about the meaning of pain become trapped in a vicious cycle of avoidance behavior, pain, and disability, as recognized in the fear-avoidance model. However, there is evidence that pain-related fear can also be seen as a common-sense response to deal with low back pain, for example, when one is told that one's back is vulnerable, degenerating, or damaged. In this instance, avoidance is a common-sense response to protect a "damaged" back. While the fear-avoidance model proposes that when someone first develops low back pain, the confrontation of normal activity in the absence of catastrophizing leads to recovery, the pathway to recovery for individuals trapped in the fear-avoidance cycle is less clear. Understanding pain-related fear from a common-sense perspective enables physical therapists to offer individuals with low back pain and high fear a pathway to recovery by altering how they make sense of their pain. Drawing on a body of published work exploring the lived experience of pain-related fear in people with low back pain, this clinical commentary illustrates how Leventhal's common-sense model may assist physical therapists to understand the broader sense-making processes involved in the fear-avoidance cycle, and how they can be altered to facilitate fear reduction by applying strategies established in the behavioral medicine literature. J Orthop Sports Phys Ther 2017;47(9):628-636. Epub 13 Jul 2017. doi:10.2519/jospt.2017.7434.

  3. The effect of transcranial direct current stimulation on experimentally induced heat pain.

    Science.gov (United States)

    Aslaksen, Per M; Vasylenko, Olena; Fagerlund, Asbjørn J

    2014-06-01

    Transcranial direct current stimulation (tDCS) is a non-invasive neuromodulatory technique that can affect human pain perception. Placebo effects are present in most treatments and could therefore also interact with treatment effects in tDCS. The present study investigated whether short-term tDCS reduced heat pain intensity, stress, blood pressure and increased heat pain thresholds in healthy volunteers when controlling for placebo effects. Seventy-five (37 females) participants were randomized into three groups: (1) active tDCS group receiving anodal tDCS (2 mA) for 7 min to the primary motor cortex (M1), (2) placebo group receiving the tDCS electrode montage but only active tDCS stimulation for 30 s and (3) natural history group that got no tDCS montage but the same pain stimulation as the active tDCS and the placebo group. Heat pain was induced by a PC-controlled thermode attached to the left forearm. Pain intensity was significantly lower in the active tDCS group when examining change scores (pretest-posttest) for the 47 °C condition. The placebo group displayed lower pain compared with the natural history group, displaying a significant placebo effect. In the 43 and 45 °C conditions, the effect of tDCS could not be separated from placebo effects. The results revealed no effects on pain thresholds. There was a tendency that active tDCS reduced stress and systolic blood pressure, however, not significant. In sum, tDCS had an analgesic effect on high-intensity pain, but the effect of tDCS could not be separated from placebo effects for medium and low pain.

  4. Tanshinone IIA Attenuates Diabetic Peripheral Neuropathic Pain in Experimental Rats via Inhibiting Inflammation

    Directory of Open Access Journals (Sweden)

    Baojian Zhang

    2018-01-01

    Full Text Available Diabetic peripheral neuropathic pain (DPNP is a common and intractable complication of diabetes. Conventional therapies are always not ideal; development of novel drugs is still needed to achieve better pain relief. Recent evidences have demonstrated that inflammation is involved in the onset and maintenance of DPNP. The anti-inflammatory property of Tanshinone IIA (TIIA makes it a promising candidate to block or alter the pain perception. This study was conducted to investigate whether TIIA could attenuate DPNP in streptozotocin- (STZ- induced rats model and its potential mechanisms. TIIA was administered to STZ-induced diabetic rats at the dose of 40 mg/kg once a day for 3 weeks. The effects of TIIA on thermal hyperalgesia and mechanical allodynia were investigated using behavioral tests. The mRNA level and expression of interleukin- (IL- 1β, interleukin- (IL- 6, tumor necrosis factor- (TNF- α, and interleukin- (IL- 10 in the fourth to sixth segments of the dorsal root ganglion (L4–6 DRG were detected by quantitative real-time PCR (qPCR and Western blot. TIIA treatment significantly attenuated mechanical allodynia and thermal hyperalgesia in diabetic rats. In addition, the expression of the proinflammatory cytokines IL-1β, IL-6, and TNF-α was inhibited, and the level of the anti-inflammatory cytokine IL-10 was increased by TIIA. This study demonstrated that TIIA has significant antiallodynic and antihyperalgesic effects in a rat model of STZ-induced DPNP, and the effect may be associated with its anti-inflammation property.

  5. Experimental pain processing in individuals with cognitive impairment: current state of the science

    DEFF Research Database (Denmark)

    Defrin, R; Amanzio, Martina; de Tomasso, M

    2015-01-01

    Cognitive impairment (CI) can develop during the course of ageing and is a feature of many neurological and neurodegenerative diseases. Many individuals with CI have substantial, sustained and complex healthcare needs which frequently include pain. However, individuals with CI can have difficulty...... of neurological and neurodegenerative disorders in which CI is typically present. Overall, the existing data suggest that pain processing is altered in most individuals with CI compared to cognitively intact matched controls. The precise nature of these alterations varies with the type of CI (or associated...... to cognitively unimpaired individuals. Our current understanding of the neurobiological mechanisms underpinning these alterations is limited, but may be enhanced through the use of animal models of CI which also exhibit alterations in nociceptive responding. Further research employing additional behavioural...

  6. Experimental Gene Therapy with Serine-Histogranin and Endomorphin 1 for the Treatment of Chronic Neuropathic Pain

    Directory of Open Access Journals (Sweden)

    Stanislava Jergova

    2017-12-01

    Full Text Available The insufficient pain relief provided by current pharmacotherapy for chronic neuropathic pain is a serious medical problem. The enhanced glutamate signaling via NMDA receptors appears to be one of the key events in the development of chronic pain. Although effective, clinical use of systemic NMDA antagonists is limited by adverse effects such as hallucinations and motor dysfunction. Opioids are also potent analgesics but their chronic use is accompanied by tolerance and risk of addiction. However, combination of NMDA antagonists and opioids seems to provide a stable pain relieve at subthreshold doses of both substances, eliminating development of side effects. Our previous research showed that combined delivery of NMDA antagonist Serine histrogranin (SHG and endomorphin1 (EM1 leads to attenuation of acute and chronic pain. The aim of this study was to design and evaluate an analgesic potency of the gene construct encoding SHG and EM1. Constructs with 1SHG copy in combination with EM1, 1SHG/EM1, and 6SHG/EM1 were intraspinally injected to animals with peripheral nerve injury-induced pain (chronic constriction injury, CCI or spinal cord injury induced pain (clip compression model, SCI and tactile and cold allodynia were evaluated. AAV2/8 particles were used for gene delivery. The results demonstrated 6SHG/EM1 as the most efficient for alleviation of pain-related behavior. The effect was observed up to 8 weeks in SCI animals, suggesting the lack of tolerance of possible synergistic effect between SHG and EM1. Intrathecal injection of SHG antibody or naloxone attenuated the analgesic effect in treated animals. Biochemical and histochemical evaluation confirmed the presence of both peptides in the spinal tissue. The results of this study showed that the injection of AAV vectors encoding combined SHG/EM constructs can provide long term attenuation of pain without overt adverse side effects. This approach may provide better treatment options for

  7. The Effectiveness of Cognitive-Behavioral Therapy on Alexithymia and Pain Self-Efficacy of Patients with Chronic Pain

    Directory of Open Access Journals (Sweden)

    Sara Saedi

    2016-11-01

    Full Text Available Chronic pain is one of the most common reasons for visit to primary medical centers. Evidences show that cognitive-behavioral therapy is the effective therapy in chronic pains. The present study evaluates the effectiveness of cognitive-behavioral therapy on alexithymia and pains self-efficacy of patients with chronic pain. For this purpose, in a quasi-experimental plan and pre-test and post-test kind with control group, 45 patients with chronic musculoskeletal pain who visited to the therapeutic-sanitary centers in Ahwaz city were selected by using the available sampling method and they were assigned randomly in two experimental and control groups. Groups were tested in terms of alexithymia and self-effectiveness of pain at first. Then behavioral-cognitive training was presented in the time of 8 sessions of 90 minutes to the group and after ending the training program and three month consistency period, both groups were tested in terms of alexithymia and self-efficacy of pain. analyzing data by multivariate covariance method showed that the behavioral-cognitive therapy has been effective on alexithymia and pain intensity of patients with chronic musculoskeletal pain and these effects remain on patients in the high amount in the consistency stage, too. According to the results, behavioral-cognitive therapy causes to increasing the self-efficacy of pain and reducing the alexithymia and harmful effects of pain to the least level by changing nonefficiency behaviors, correction of adverse cognitions and destructive emotions related to pain.

  8. Perineural pretreatment of bee venom attenuated the development of allodynia in the spinal nerve ligation injured neuropathic pain model; an experimental study.

    Science.gov (United States)

    Koh, Won Uk; Choi, Seong Soo; Lee, Jong Hyuk; Lee, So Hee; Lee, Sun Kyung; Lee, Yoon Kyung; Leem, Jeong Gil; Song, Jun Gol; Shin, Jin Woo

    2014-11-04

    Diluted bee venom (BV) is known to have anti-nociceptive and anti-inflammatory effects. We therefore assessed whether perineural bee venom pretreatment could attenuate the development of neuropathic pain in the spinal nerve ligation injured animal model. Neuropathic pain was surgically induced in 30 male Sprague Dawley rats by ligation of the L5 and L6 spinal nerves, with 10 rats each treated with saline and 0.05 and 0.1 mg BV. Behavioral testing for mechanical, cold, and thermal allodynia was conducted on postoperative days 3 to 29. Three rats in each group and 9 sham operated rats were sacrificed on day 9, and the expression of transient receptor potential vanilloid type 1 (TRPV1), ankyrin type 1 (TRPA1), and melastatin type 8 (TRPM8) receptors in the ipsilateral L5 dorsal root ganglion was analyzed. The perineural administration of BV to the spinal nerves attenuated the development of mechanical, thermal, and cold allodynia, and the BV pretreatment reduced the expression of TRPV1, TRPA1, TRPM8 and c - Fos in the ipsilateral dorsal root ganglion. The current study demonstrates that the perineural pretreatment with diluted bee venom before the induction of spinal nerve ligation significantly suppresses the development of neuropathic pain. Furthermore, this bee venom induced suppression was strongly related with the involvement of transient receptor potential family members.

  9. Pain-related anxiety influences pain perception differently in men and women: a quantitative sensory test across thermal pain modalities.

    Science.gov (United States)

    Thibodeau, Michel A; Welch, Patrick G; Katz, Joel; Asmundson, Gordon J G

    2013-03-01

    The sexes differ with respect to perception of experimental pain. Anxiety influences pain perception more in men than in women; however, there lacks research exploring which anxiety constructs influence pain perception differentially between men and women. Furthermore, research examining whether depression is associated with pain perception differently between the sexes remains scant. The present investigation was designed to examine how trait anxiety, pain-related anxiety constructs (ie, fear of pain, pain-related anxiety, anxiety sensitivity), and depression are associated with pain perception between the sexes. A total of 95 nonclinical participants (55% women) completed measures assessing the constructs of interest and participated in quantitative sensory testing using heat and cold stimuli administered by a Medoc Pathway Pain and Sensory Evaluation System. The findings suggest that pain-related anxiety constructs, but not trait anxiety, are associated with pain perception. Furthermore, these constructs are associated with pain intensity ratings in men and pain tolerance levels in women. This contrasts with previous research suggesting that anxiety influences pain perception mostly or uniquely in men. Depression was not systematically associated with pain perception in either sex. Systematic relationships were not identified that allow conclusions regarding how fear of pain, pain-related anxiety, and anxiety sensitivity may contribute to pain perception differentially in men and women; however, anxiety sensitivity was associated with increased pain tolerance, a novel finding needing further examination. The results provide directions for future research and clinical endeavors and support that fear and anxiety are important features associated with hyperalgesia in both men and women. Copyright © 2012 International Association for the Study of Pain. Published by Elsevier B.V. All rights reserved.

  10. The Src family kinase inhibitor dasatinib delays pain-related behaviour and conserves bone in a rat model of cancer-induced bone pain

    DEFF Research Database (Denmark)

    Appel, Camilla Kristine; Gallego-Pedersen, Simone; Andersen, Line

    2017-01-01

    -induced bone pain, including cancer growth, osteoclastic bone degradation and nociceptive signalling. Here we investigate the role of dasatinib, an oral Src kinase family and Bcr-Abl tyrosine kinase inhibitor, in an animal model of cancer-induced bone pain. Daily administration of dasatinib (15 mg/kg, p...

  11. Uncovering the influence of social skills and psychosociological factors on pain sensitivity using structural equation modeling.

    Science.gov (United States)

    Tanaka, Yoichi; Nishi, Yuki; Nishi, Yuki; Osumi, Michihiro; Morioka, Shu

    2017-01-01

    Pain is a subjective emotional experience that is influenced by psychosociological factors such as social skills, which are defined as problem-solving abilities in social interactions. This study aimed to reveal the relationships among pain, social skills, and other psychosociological factors by using structural equation modeling. A total of 101 healthy volunteers (41 men and 60 women; mean age: 36.6±12.7 years) participated in this study. To evoke participants' sense of inner pain, we showed them images of painful scenes on a PC screen and asked them to evaluate the pain intensity by using the visual analog scale (VAS). We examined the correlation between social skills and VAS, constructed a hypothetical model based on results from previous studies and the current correlational analysis results, and verified the model's fit using structural equation modeling. We found significant positive correlations between VAS and total social skills values, as well as between VAS and the "start of relationships" subscales. Structural equation modeling revealed that the values for "start of relationships" had a direct effect on VAS values (path coefficient =0.32, p social support. The results indicated that extroverted people are more sensitive to inner pain and tend to get more social support and maintain a better psychological condition.

  12. Symptoms of Fibromyalgia According to the 2016 Revised Fibromyalgia Criteria in Chronic Pain Patients Referred to Multidisciplinary Pain Rehabilitation: Influence on Clinical and Experimental Pain Sensitivity

    DEFF Research Database (Denmark)

    Plesner, Karin Bruun; Vaegter, Henrik Bjarke

    2018-01-01

    Fibromyalgia is a condition with chronic widespread pain and signs of generalized pain hypersensitivity. FM has previously been classified according to the ACR1990 criteria, where the presence of hypersensitivity is estimated by a tender point examination. Due to the limitations of these classifi......Fibromyalgia is a condition with chronic widespread pain and signs of generalized pain hypersensitivity. FM has previously been classified according to the ACR1990 criteria, where the presence of hypersensitivity is estimated by a tender point examination. Due to the limitations...... of these classification criteria, new diagnostic criteria have been proposed, abandoning this examination. This cross-sectional study investigated the prevalence of FM according to the revised 2016 FM criteria in a large cohort of chronic pain patients. Pain drawings, the Fibromyalgia Symptom Severity Scale...

  13. The impact of a pain assessment intervention on pain score and analgesic use in older nursing home residents with severe dementia: A cluster randomised controlled trial.

    Science.gov (United States)

    Rostad, Hanne Marie; Utne, Inger; Grov, Ellen Karine; Småstuen, Milada Cvancarova; Puts, Martine; Halvorsrud, Liv

    2018-04-30

    Pain is highly prevalent in older adults, especially those in institutional settings such as nursing homes. The presence of dementia may increase the risk of underdiagnosed and undertreated pain. Pain assessment tools are not regularly used in clinical practice, however, there are indications that the regular use of pain assessments tools may influence the recognition of pain by nursing staff and thereby affect pain management. To assess whether regular pain assessment using a pain assessment tool is associated with changes in i) pain scores and ii) analgesic use in nursing home residents with severe dementia. Cluster-randomised controlled trial. The study was conducted in 16 nursing homes in four counties in Norway. A total of 112 nursing home residents aged 65 years and older with dementia who lacked the capacity for self-reporting pain or were non-verbal. The experimental group were regularly assessed pain with a standardised pain scale (the Doloplus-2) twice a week for a 12-week intervention period. The control group received usual care. The primary outcome was pain score measured with the Doloplus-2, and the secondary outcome was analgesic use (oral morphine equivalents and milligram/day paracetamol). Data on the outcomes were collected at baseline and at the end of week 12. The nursing staff in both the experimental and the control groups received training to collect the data. Linear mixed models were used to assess possible between-group difference over time. No overall effect of regular pain assessment was found on pain score or analgesic use. The mean score of Doloplus-2 and analgesic use remained unchanged and above the established cut-off in both groups. The current intervention did not change analgesic use or pain score compared with the control condition. However, there is not sufficient evidence to conclude that regular pain assessment using a pain assessment tool is not clinically relevant. Furthermore, our results indicated that pain continued to be

  14. Intervertebral Foramen Injection of Ozone Relieves Mechanical Allodynia and Enhances Analgesic Effect of Gabapentin in Animal Model of Neuropathic Pain.

    Science.gov (United States)

    Luo, Wen-Jun; Yang, Fan; Yang, Fei; Sun, Wei; Zheng, Wei; Wang, Xiao-Liang; Wu, Fang-Fang; Wang, Jiang-Lin; Wang, Jia-Shuang; Guan, Su-Min; Chen, Jun

    2017-07-01

    In a 5-year follow-up study in a hospital in southern China, it was shown that intervertebral foramen (IVF) injection of ozone at the involved segmental levels could significantly alleviate paroxysmal spontaneous pain and mechanical allodynia in patients with chronic, intractable postherpetic neuralgia (PHN) and improve the quality of life. However, so far no proof-of-concept studies in animals have been available. This study was designed to investigate whether IVF ozone has an analgesic effect on animal models of neuropathic and inflammatory pain. Experimental trial in rats. Institute for Biomedical Sciences of Pain. By IVF injection, a volume of 50 µl containing 30 µg/mL ozone-oxygen mixture or 50 µl air was carried out on male Sprague-Dawley rats of naïve, inflammatory pain states produced by injections of either bee venom or complete Freud's adjuvant, and neuropathic pain state produced by spared nerve injury, respectively. The effects of IVF ozone on pain-related behaviors were evaluated for 2 weeks or one month. Then combined use of gabapentin (100 mg/1 kg body weight) with IVF ozone was evaluated in rats with neuropathic pain by intraperitoneal administration 5 days after the ozone treatment. Finally, the analgesic effects of another 4 drugs, AMD3100 (a CXCR4 antagonist), A-803467 (a selective Nav1.8 blocker), rapamycin (the mTOR inhibitor), and MGCD0103 (a selective histone deacetylase inhibitor) were evaluated for long term through IVF injection, respectively. (1) IVF injection of ozone at L4-5 was only effective in suppression of mechanical allodynia in rats with neuropathic pain but not with inflammatory pain; (2) the analgesic effects of IVF ozone lasted much longer (> 14 days) than other selective molecular target drugs (bee venom, complete Freud's adjuvant.

  15. Abnormal muscle afferent function in a model of Taxol chemotherapy-induced painful neuropathy

    OpenAIRE

    Chen, Xiaojie; Green, Paul G.; Levine, Jon D.

    2011-01-01

    Despite muscle pain being a well-described symptom in patients with diverse forms of peripheral neuropathy, the role of neuropathic mechanisms in muscle pain have received remarkably little attention. We have recently demonstrated in a well-established model of chemotherapy-induced painful neuropathy (CIPN) that the anti-tumor drug paclitaxel (Taxol) produces mechanical hyperalgesia in skeletal muscle, of similar time course to and with shared mechanism with cutaneous symptoms. In the present...

  16. Language and the pain experience.

    Science.gov (United States)

    Wilson, Dianne; Williams, Marie; Butler, David

    2009-03-01

    People in persistent pain have been reported to pay increased attention to specific words or descriptors of pain. The amount of attention paid to pain or cues for pain (such as pain descriptors), has been shown to be a major factor in the modulation of persistent pain. This relationship suggests the possibility that language may have a role both in understanding and managing the persistent pain experience. The aim of this paper is to describe current models of neuromatrices for pain and language, consider the role of attention in persistent pain states and highlight discrepancies, in previous studies based on the McGill Pain Questionnaire (MPQ), of the role of attention on pain descriptors. The existence of a pain neuromatrix originally proposed by Melzack (1990) has been supported by emerging technologies. Similar technologies have recently allowed identification of multiple areas of involvement for the processing of auditory input and the construction of language. As with the construction of pain, this neuromatrix for speech and language may intersect with neural systems for broader cognitive functions such as attention, memory and emotion. A systematic search was undertaken to identify experimental or review studies, which specifically investigated the role of attention on pain descriptors (as cues for pain) in persistent pain patients. A total of 99 articles were retrieved from six databases, with 66 articles meeting the inclusion criteria. After duplicated articles were eliminated, the remaining 41 articles were reviewed in order to support a link between persistent pain, pain descriptors and attention. This review revealed a diverse range of specific pain descriptors, the majority of which were derived from the MPQ. Increased attention to pain descriptors was consistently reported to be associated with emotional state as well as being a significant factor in maintaining persistent pain. However, attempts to investigate the attentional bias of specific pain

  17. Frutalin reduces acute and neuropathic nociceptive behaviours in rodent models of orofacial pain.

    Science.gov (United States)

    Damasceno, Marina B M V; de Melo Júnior, José de Maria A; Santos, Sacha Aubrey A R; Melo, Luana T M; Leite, Laura Hévila I; Vieira-Neto, Antonio E; Moreira, Renato de A; Monteiro-Moreira, Ana Cristina de O; Campos, Adriana R

    2016-08-25

    Orofacial pain is a highly prevalent clinical condition, yet difficult to control effectively with available drugs. Much attention is currently focused on the anti-inflammatory and antinociceptive properties of lectins. The purpose of this study was to evaluate the antinociceptive effect of frutalin (FTL) using rodent models of inflammatory and neuropathic orofacial pain. Acute pain was induced by formalin, glutamate or capsaicin (orofacial model) and hypertonic saline (corneal model). In one experiment, animals were pretreated with l-NAME and naloxone to investigate the mechanism of antinociception. The involvement of the lectin domain in the antinociceptive effect of FTL was verified by allowing the lectin to bind to its specific ligand. In another experiment, animals pretreated with FTL or saline were submitted to the temporomandibular joint formalin test. In yet another, animals were submitted to infraorbital nerve transection to induce chronic pain, followed by induction of thermal hypersensitivity using acetone. Motor activity was evaluated with the rotarod test. A molecular docking was performed using the TRPV1 channel. Pretreatment with FTL significantly reduced nociceptive behaviour associated with acute and neuropathic pain, especially at 0.5 mg/kg. Antinociception was effectively inhibited by l-NAME and d-galactose. In line with in vivo experiments, docking studies indicated that FTL may interact with TRPV1. Our results confirm the potential pharmacological relevance of FTL as an inhibitor of orofacial nociception in acute and chronic pain mediated by TRPA1, TRPV1 and TRPM8 receptor. Copyright © 2016. Published by Elsevier Ireland Ltd.

  18. Female reproductive tract pain: targets, challenges, and outcomes

    Directory of Open Access Journals (Sweden)

    Phillip eJobling

    2014-02-01

    Full Text Available Pain from the female reproductive tract (FRT is a significant clinical problem for which there are few effective therapies. The complex neuroantomy of pelvic organs not only makes diagnosis of pelvic pain disorders difficult but represents a challenge to development of targeted therapies. A number of potential therapeutic targets have been identified on sensory neurons supplying the FRT but our knowledge on the basic neurophysiology of these neurons is limited compared with other viscera. Until this is addressed we can only guess if the new experimental therapies proposed for somatic, gastrointestinal or bladder pain will translate to the FRT. Once suitable therapeutic targets become clear, the next challenge is drug delivery. The FRT represents a promising system for topical drug delivery that could be tailored to act locally or systemically depending on formulation. Development of these therapies and their delivery systems will need to be done in concert with more robust in vivo and in vitro models of FRT pain.

  19. Experimentally induced masseter-pain changes masseter but not sternocleidomastoid muscle-related activity during mastication.

    Science.gov (United States)

    Pasinato, Fernanda; Santos-Couto-Paz, Clarissa C; Zeredo, Jorge Luis Lopes; Macedo, Sergio Bruzadelli; Corrêa, Eliane C R

    2016-12-01

    The aim of this study was to verify the effects of induced masseter-muscle pain on the amplitude of muscle activation, symmetry and coactivation of jaw- and neck-muscles during mastication. Twenty-eight male volunteers, mean age±SD 20.6±2.0years, participated in this study. Surface electromyography of the masseter and sternocleidomastoid (SCM) muscles was performed bilaterally during mastication of a gummy candy before and after injections of monosodium glutamate solution and isotonic saline solution. As a result, we observed a decrease in the amplitude of activation of the masseter muscle on the working side (p=0.009; d=0.34) and a reduction in the asymmetry between the working and the balancing side during mastication (p=0.007; d=0.38). No changes were observed either on the craniocervical electromyographic variables. In conclusion, experimentally induced pain reduced the masseter muscle activation on the working side, thereby reducing the physiological masseters' recruitment asymmetry between the two sides during mastication. No effects on SCM activity were detected. These results may partly explain the initial maladaptative changes underlying TMD conditions. Copyright © 2016 Elsevier Ltd. All rights reserved.

  20. Influence of exercise on visceral pain

    DEFF Research Database (Denmark)

    van Weerdenburg, Laura Jgm; Brock, Christina; Drewes, Asbjørn Mohr

    2017-01-01

    Background and objectives: Contradictory results have been found about the effect of different exercise modalities on pain. The aim of this study was to investigate the early effects of aerobic and isometric exercise on different types of experimental pain, including visceral pain, compared...... intervention, psychophysical tests were performed, including electrical stimulation of the esophagus, pressure pain thresholds and the cold pressor test as a measure for conditioned pain modulation. Participants completed the Medical Outcome Study Short-Form 36 and State- Trait Anxiety Inventory prior...

  1. Acoustic analysis and mood classification of pain-relieving music.

    Science.gov (United States)

    Knox, Don; Beveridge, Scott; Mitchell, Laura A; MacDonald, Raymond A R

    2011-09-01

    Listening to preferred music (that which is chosen by the participant) has been shown to be effective in mitigating the effects of pain when compared to silence and a variety of distraction techniques. The wide range of genre, tempo, and structure in music chosen by participants in studies utilizing experimentally induced pain has led to the assertion that structure does not play a significant role, rather listening to preferred music renders the music "functionally equivalent" as regards its effect upon pain perception. This study addresses this assumption and performs detailed analysis of a selection of music chosen from three pain studies. Music analysis showed significant correlation between timbral and tonal aspects of music and measurements of pain tolerance and perceived pain intensity. Mood classification was performed using a hierarchical Gaussian Mixture Model, which indicated the majority of the chosen music expressed contentment. The results suggest that in addition to personal preference, associations with music and the listening context, emotion expressed by music, as defined by its acoustical content, is important to enhancing emotional engagement with music and therefore enhances the level of pain reduction and tolerance. © 2011 Acoustical Society of America

  2. Botulinum toxin A, brain and pain.

    Science.gov (United States)

    Matak, Ivica; Lacković, Zdravko

    2014-01-01

    Botulinum neurotoxin type A (BoNT/A) is one of the most potent toxins known and a potential biological threat. At the same time, it is among the most widely used therapeutic proteins used yearly by millions of people, especially for cosmetic purposes. Currently, its clinical use in certain types of pain is increasing, and its long-term duration of effects represents a special clinical value. Efficacy of BoNT/A in different types of pain has been found in numerous clinical trials and case reports, as well as in animal pain models. However, sites and mechanisms of BoNT/A actions involved in nociception are a matter of controversy. In analogy with well known neuroparalytic effects in peripheral cholinergic synapses, presently dominant opinion is that BoNT/A exerts pain reduction by inhibiting peripheral neurotransmitter/inflammatory mediator release from sensory nerves. On the other hand, growing number of behavioral and immunohistochemical studies demonstrated the requirement of axonal transport for BoNT/A's antinociceptive action. In addition, toxin's enzymatic activity in central sensory regions was clearly identified after its peripheral application. Apart from general pharmacology, this review summarizes the clinical and experimental evidence for BoNT/A antinociceptive activity and compares the data in favor of peripheral vs. central site and mechanism of action. Based on literature review and published results from our laboratory we propose that the hypothesis of peripheral site of BoNT/A action is not sufficient to explain the experimental data collected up to now. Copyright © 2014 Elsevier Ltd. All rights reserved.

  3. Music for pain relief.

    Science.gov (United States)

    Cepeda, M S; Carr, D B; Lau, J; Alvarez, H

    2006-04-19

    The efficacy of music for the treatment of pain has not been established. To evaluate the effect of music on acute, chronic or cancer pain intensity, pain relief, and analgesic requirements. We searched The Cochrane Library, MEDLINE, EMBASE, PsycINFO, LILACS and the references in retrieved manuscripts. There was no language restriction. We included randomized controlled trials that evaluated the effect of music on any type of pain in children or adults. We excluded trials that reported results of concurrent non-pharmacological therapies. Data was extracted by two independent review authors. We calculated the mean difference in pain intensity levels, percentage of patients with at least 50% pain relief, and opioid requirements. We converted opioid consumption to morphine equivalents. To explore heterogeneity, studies that evaluated adults, children, acute, chronic, malignant, labor, procedural, or experimental pain were evaluated separately, as well as those studies in which patients chose the type of music. Fifty-one studies involving 1867 subjects exposed to music and 1796 controls met inclusion criteria. In the 31 studies evaluating mean pain intensity there was a considerable variation in the effect of music, indicating statistical heterogeneity ( I(2) = 85.3%). After grouping the studies according to the pain model, this heterogeneity remained, with the exception of the studies that evaluated acute postoperative pain. In this last group, patients exposed to music had pain intensity that was 0.5 units lower on a zero to ten scale than unexposed subjects (95% CI: -0.9 to -0.2). Studies that permitted patients to select the music did not reveal a benefit from music; the decline in pain intensity was 0.2 units, 95% CI (-0.7 to 0.2). Four studies reported the proportion of subjects with at least 50% pain relief; subjects exposed to music had a 70% higher likelihood of having pain relief than unexposed subjects (95% CI: 1.21 to 2.37). NNT = 5 (95% CI: 4 to 13). Three

  4. The role of pain behaviour and family caregiver responses in the link between pain catastrophising and pain intensity : A moderated mediation model

    NARCIS (Netherlands)

    Mohammadi, Somayyeh; Dehghani, Mohsen; Sanderman, Robbert; Hagedoorn, Mariët

    2017-01-01

    Objectives: This study investigated the mediating role of pain behaviours in the association between pain catastrophising and pain intensity and explored the moderating role of family caregivers’ responses to pain in the link between pain behaviours and pain intensity. Methods: The sample consisted

  5. The role of pain behaviour and family caregiver responses in the link between pain catastrophising and pain intensity : A moderated mediation model

    NARCIS (Netherlands)

    Mohammadi, Somayyeh; Dehghani, Mohsen; Sanderman, Robbert; Hagedoorn, Mariet

    2017-01-01

    Objectives: This study investigated the mediating role of pain behaviours in the association between pain catastrophising and pain intensity and explored the moderating role of family caregivers' responses to pain in the link between pain behaviours and pain intensity. Methods: The sample consisted

  6. Electronic Gaming as Pain Distraction

    Directory of Open Access Journals (Sweden)

    Eleanor Jameson

    2011-01-01

    Full Text Available The current study investigated whether active distraction reduces participants’ experience of pain more than passive distraction during a cold pressor task. In the first experiment, 60 participants were asked to submerge their hand in cold (2°C water for as long as they could tolerate. They did this with no distraction, and then with active (electronic gaming system and passive (television distraction, in randomly assigned order. Tolerance time, pain intensity ratings and task absorption ratings were measured for each condition. A second experiment attempted to control for participants’ expectations about the effects of distraction on pain. Forty participants underwent the same experimental procedure, but were given verbal suggestions about the effects of distraction by the experimenter before each distraction condition. Participants in both experiments had a significantly higher pain tolerance and reported less pain with the active distraction compared with passive or no distraction. Participants reported being more absorbed, and were significantly more willing to do the task again when they had the active distraction compared with both passive distraction and no distraction. They also had more enjoyment, less anxiety and greater reduction in pain with active distraction than with passive distraction. There was no effect of suggestion. These experiments offer further support for the use of electronic games as a method of pain control.

  7. Pain without nociceptors?

    DEFF Research Database (Denmark)

    Minett, Michael S; Falk, Sarah; Santana-Varela, Sonia

    2014-01-01

    Nav1.7, a peripheral neuron voltage-gated sodium channel, is essential for pain and olfaction in mice and humans. We examined the role of Nav1.7 as well as Nav1.3, Nav1.8, and Nav1.9 in different mouse models of chronic pain. Constriction-injury-dependent neuropathic pain is abolished when Nav1.......7 is deleted in sensory neurons, unlike nerve-transection-related pain, which requires the deletion of Nav1.7 in sensory and sympathetic neurons for pain relief. Sympathetic sprouting that develops in parallel with nerve-transection pain depends on the presence of Nav1.7 in sympathetic neurons. Mechanical...... and cold allodynia required distinct sets of neurons and different repertoires of sodium channels depending on the nerve injury model. Surprisingly, pain induced by the chemotherapeutic agent oxaliplatin and cancer-induced bone pain do not require the presence of Nav1.7 sodium channels or Nav1.8-positive...

  8. Clinical diagnostic model for sciatica developed in primary care patients with low back-related leg pain

    Science.gov (United States)

    Konstantinou, Kika; Ogollah, Reuben; Hay, Elaine M.; Dunn, Kate M.

    2018-01-01

    Background Identification of sciatica may assist timely management but can be challenging in clinical practice. Diagnostic models to identify sciatica have mainly been developed in secondary care settings with conflicting reference standard selection. This study explores the challenges of reference standard selection and aims to ascertain which combination of clinical assessment items best identify sciatica in people seeking primary healthcare. Methods Data on 394 low back-related leg pain consulters were analysed. Potential sciatica indicators were seven clinical assessment items. Two reference standards were used: (i) high confidence sciatica clinical diagnosis; (ii) high confidence sciatica clinical diagnosis with confirmatory magnetic resonance imaging findings. Multivariable logistic regression models were produced for both reference standards. A tool predicting sciatica diagnosis in low back-related leg pain was derived. Latent class modelling explored the validity of the reference standard. Results Model (i) retained five items; model (ii) retained six items. Four items remained in both models: below knee pain, leg pain worse than back pain, positive neural tension tests and neurological deficit. Model (i) was well calibrated (p = 0.18), discrimination was area under the receiver operating characteristic curve (AUC) 0.95 (95% CI 0.93, 0.98). Model (ii) showed good discrimination (AUC 0.82; 0.78, 0.86) but poor calibration (p = 0.004). Bootstrapping revealed minimal overfitting in both models. Agreement between the two latent classes and clinical diagnosis groups defined by model (i) was substantial, and fair for model (ii). Conclusion Four clinical assessment items were common in both reference standard definitions of sciatica. A simple scoring tool for identifying sciatica was developed. These criteria could be used clinically and in research to improve accuracy of identification of this subgroup of back pain patients. PMID:29621243

  9. "The empathy impulse: A multinomial model of intentional and unintentional empathy for pain": Correction.

    Science.gov (United States)

    2018-04-01

    Reports an error in "The empathy impulse: A multinomial model of intentional and unintentional empathy for pain" by C. Daryl Cameron, Victoria L. Spring and Andrew R. Todd ( Emotion , 2017[Apr], Vol 17[3], 395-411). In this article, there was an error in the calculation of some of the effect sizes. The w effect size was manually computed incorrectly. The incorrect number of total observations was used, which affected the final effect size estimates. This computing error does not change any of the results or interpretations about model fit based on the G² statistic, or about significant differences across conditions in process parameters. Therefore, it does not change any of the hypothesis tests or conclusions. The w statistics for overall model fit should be .02 instead of .04 in Study 1, .01 instead of .02 in Study 2, .01 instead of .03 for the OIT in Study 3 (model fit for the PIT remains the same: .00), and .02 instead of .03 in Study 4. The corrected tables can be seen here: http://osf.io/qebku at the Open Science Framework site for the article. (The following abstract of the original article appeared in record 2017-01641-001.) Empathy for pain is often described as automatic. Here, we used implicit measurement and multinomial modeling to formally quantify unintentional empathy for pain: empathy that occurs despite intentions to the contrary. We developed the pain identification task (PIT), a sequential priming task wherein participants judge the painfulness of target experiences while trying to avoid the influence of prime experiences. Using multinomial modeling, we distinguished 3 component processes underlying PIT performance: empathy toward target stimuli (Intentional Empathy), empathy toward prime stimuli (Unintentional Empathy), and bias to judge target stimuli as painful (Response Bias). In Experiment 1, imposing a fast (vs. slow) response deadline uniquely reduced Intentional Empathy. In Experiment 2, inducing imagine-self (vs. imagine

  10. Localized Sympathectomy Reduces Mechanical Hypersensitivity by Restoring Normal Immune Homeostasis in Rat Models of Inflammatory Pain.

    Science.gov (United States)

    Xie, Wenrui; Chen, Sisi; Strong, Judith A; Li, Ai-Ling; Lewkowich, Ian P; Zhang, Jun-Ming

    2016-08-17

    Some forms of chronic pain are maintained or enhanced by activity in the sympathetic nervous system (SNS), but attempts to model this have yielded conflicting findings. The SNS has both pro- and anti-inflammatory effects on immunity, confounding the interpretation of experiments using global sympathectomy methods. We performed a "microsympathectomy" by cutting the ipsilateral gray rami where they entered the spinal nerves near the L4 and L5 DRG. This led to profound sustained reductions in pain behaviors induced by local DRG inflammation (a rat model of low back pain) and by a peripheral paw inflammation model. Effects of microsympathectomy were evident within one day, making it unlikely that blocking sympathetic sprouting in the local DRGs or hindpaw was the sole mechanism. Prior microsympathectomy greatly reduced hyperexcitability of sensory neurons induced by local DRG inflammation observed 4 d later. Microsympathectomy reduced local inflammation and macrophage density in the affected tissues (as indicated by paw swelling and histochemical staining). Cytokine profiling in locally inflamed DRG showed increases in pro-inflammatory Type 1 cytokines and decreases in the Type 2 cytokines present at baseline, changes that were mitigated by microsympathectomy. Microsympathectomy was also effective in reducing established pain behaviors in the local DRG inflammation model. We conclude that the effect of sympathetic fibers in the L4/L5 gray rami in these models is pro-inflammatory. This raises the possibility that therapeutic interventions targeting gray rami might be useful in some chronic inflammatory pain conditions. Sympathetic blockade is used for many pain conditions, but preclinical studies show both pro- and anti-nociceptive effects. The sympathetic nervous system also has both pro- and anti-inflammatory effects on immune tissues and cells. We examined effects of a very localized sympathectomy. By cutting the gray rami to the spinal nerves near the lumbar sensory

  11. Administration of a co-crystal of tramadol and celecoxib in a 1:1 molecular ratio produces synergistic antinociceptive effects in a postoperative pain model in rats.

    Science.gov (United States)

    Merlos, Manuel; Portillo-Salido, Enrique; Brenchat, Alex; Aubel, Bertrand; Buxens, Jordi; Fisas, Angels; Codony, Xavier; Romero, Luz; Zamanillo, Daniel; Vela, José Miguel

    2018-06-19

    Drug combination for the treatment of pain is common clinical practice. Co-crystal of Tramadol-Celecoxib (CTC) consists of two active pharmaceutical ingredients (APIs), namely the atypical opioid tramadol and the preferential cyclooxygenase-2 inhibitor celecoxib, at a 1:1 molecular ratio. In this study, a non-formulated 'raw' form of CTC administered in suspension (referred to as ctc susp ) was compared with both tramadol and celecoxib alone in a rat plantar incision postoperative pain model. For comparison, the strong opioids morphine and oxycodone, and a tramadol plus acetaminophen combination at a molecular ratio of 1:17 were also tested. Isobolographic analyses showed that ctc susp exerted synergistic mechanical antiallodynic (experimental ED 50 =2.0±0.5mg/kg, i.p.; theoretical ED 50 =3.8±0.4mg/kg, i.p.) and thermal (experimental ED 50 =2.3±0.5mg/kg, i.p.; theoretical ED 50 =9.8±0.8mg/kg, i.p.) antihyperalgesic effects in the postoperative pain model. In contrast, the tramadol and acetaminophen combination showed antagonistic effects on both mechanical allodynia and thermal hyperalgesia. No synergies between tramadol and celecoxib on locomotor activity, motor coordination, ulceration potential and gastrointestinal transit were observed after the administration of ctc susp . Overall, rat efficacy and safety data revealed that ctc susp provided synergistic analgesic effects compared with each API alone, without enhancing adverse effects. Moreover, ctc susp showed similar efficacy but improved safety ratio (80, measured as gastrointestinal transit vs postoperative pain ED 50 ratios) compared with the strong opioids morphine (2.5) and oxycodone (5.8). The overall in vivo profile of ctc susp supports the further investigation of CTC in the clinical management of moderate-to-severe acute pain as an alternative to strong opioids. Copyright © 2018. Published by Elsevier B.V.

  12. Experimental models of demyelination and remyelination.

    Science.gov (United States)

    Torre-Fuentes, L; Moreno-Jiménez, L; Pytel, V; Matías-Guiu, J A; Gómez-Pinedo, U; Matías-Guiu, J

    2017-08-29

    Experimental animal models constitute a useful tool to deepen our knowledge of central nervous system disorders. In the case of multiple sclerosis, however, there is no such specific model able to provide an overview of the disease; multiple models covering the different pathophysiological features of the disease are therefore necessary. We reviewed the different in vitro and in vivo experimental models used in multiple sclerosis research. Concerning in vitro models, we analysed cell cultures and slice models. As for in vivo models, we examined such models of autoimmunity and inflammation as experimental allergic encephalitis in different animals and virus-induced demyelinating diseases. Furthermore, we analysed models of demyelination and remyelination, including chemical lesions caused by cuprizone, lysolecithin, and ethidium bromide; zebrafish; and transgenic models. Experimental models provide a deeper understanding of the different pathogenic mechanisms involved in multiple sclerosis. Choosing one model or another depends on the specific aims of the study. Copyright © 2017 Sociedad Española de Neurología. Publicado por Elsevier España, S.L.U. All rights reserved.

  13. Potential of Endocannabinoids to Control Bladder Pain

    Directory of Open Access Journals (Sweden)

    Dale E. Bjorling

    2018-05-01

    Full Text Available Bladder-related pain is one of the most common forms of visceral pain, and visceral pain is among the most common complaints for which patients seek physician consultation. Despite extensive studies of visceral innervation and treatment of visceral pain, opioids remain a mainstay for management of bladder pain. Side effects associated with opioid therapy can profoundly diminish quality of life, and improved options for treatment of bladder pain remain a high priority. Endocannabinoids, primarily anandamide (AEA and 2-arachidonoylglycerol (2-AG, are endogenously-produced fatty acid ethanolamides with that induce analgesia. Animal experiments have demonstrated that inhibition of enzymes that degrade AEA or 2-AG have the potential to prevent development of visceral and somatic pain. Although experimental results in animal models have been promising, clinical application of this approach has proven difficult. In addition to fatty acid amide hydrolase (FAAH; degrades AEA and monacylglycerol lipase (MAGL; degrades 2-AG, cyclooxygenase (COX acts to metabolize endocannabinoids. Another potential limitation of this strategy is that AEA activates pro-nociceptive transient receptor potential vanilloid 1 (TRPV1 channels. Dual inhibitors of FAAH and TRPV1 or FAAH and COX have been synthesized and are currently undergoing preclinical testing for efficacy in providing analgesia. Local inhibition of FAAH or MAGL within the bladder may be viable options to reduce pain associated with cystitis with fewer systemic side effects, but this has not been explored. Further investigation is required before manipulation of the endocannabinoid system can be proven as an efficacious alternative for management of bladder pain.

  14. Social learning pathways in the relation between parental chronic pain and daily pain severity and functional impairment in adolescents with functional abdominal pain.

    Science.gov (United States)

    Stone, Amanda L; Bruehl, Stephen; Smith, Craig A; Garber, Judy; Walker, Lynn S

    2017-10-06

    Having a parent with chronic pain (CP) may confer greater risk for persistence of CP from childhood into young adulthood. Social learning, such as parental modeling and reinforcement, represents one plausible mechanism for the transmission of risk for CP from parents to offspring. Based on a 7-day pain diary in 154 pediatric patients with functional abdominal CP, we tested a model in which parental CP predicted adolescents' daily average CP severity and functional impairment (distal outcomes) via parental modeling of pain behaviors and parental reinforcement of adolescent's pain behaviors (mediators) and adolescents' cognitive appraisals of pain threat (proximal outcome representing adolescents' encoding of parents' behaviors). Results indicated significant indirect pathways from parental CP status to adolescent average daily pain severity (b = 0.18, SE = 0.08, 95% CI: 0.04, 0.31, p = 0.03) and functional impairment (b = 0.08, SE = 0.04, 95% CI: 0.02, 0.15, p = 0.03) over the 7-day diary period via adolescents' observations of parent pain behaviors and adolescent pain threat appraisal. The indirect pathway through parental reinforcing responses to adolescents' pain did not reach significance for either adolescent pain severity or functional impairment. Identifying mechanisms of increased risk for pain and functional impairment in children of parents with CP ultimately could lead to targeted interventions aimed at improving functioning and quality of life in families with chronic pain. Parental modeling of pain behaviors represents a potentially promising target for family based interventions to ameliorate pediatric chronic pain.

  15. Genes contributing to pain sensitivity in the normal population

    DEFF Research Database (Denmark)

    Williams, Frances M.K.; Scollen, Serena; Cao, Dandan

    2012-01-01

    Sensitivity to pain varies considerably between individuals and is known to be heritable. Increased sensitivity to experimental pain is a risk factor for developing chronic pain, a common and debilitating but poorly understood symptom. To understand mechanisms underlying pain sensitivity and to s...

  16. Predictors of opioid efficacy in patients with chronic pain

    DEFF Research Database (Denmark)

    Grosen, Kasper; Olesen, Anne E; Gram, Mikkel

    2017-01-01

    of life after 14 days of opioid treatment. Secondary outcomes included patient's global impression of clinical change and side effects. Logistic regression models adjusted for age and sex were used to identify biomarkers predictive for successful treatment, defined as at least a 30% reduction in average.......03), relative delta (OR: 0.76; P = 0.03) and beta EEG activity (OR: 1.18; P = 0.04) induced by experimental cold pain. None of the study variables were related to improvement in quality of life. For the first time, individual pain processing characteristics have been linked to opioid response in a mixed chronic...

  17. Night-shift work is associated with increased pain perception.

    Science.gov (United States)

    Matre, Dagfinn; Knardahl, Stein; Nilsen, Kristian Bernhard

    2017-05-01

    Objectives The aim of the present study was to determine whether shift workers exhibit increased perception of experimentally induced pain after working night shifts. Methods The study was a paired cross-over design with two sleep conditions, after at least two nights of habitual sleep and after two consecutive night shifts at work. Fifty-three nurses in rotating shift work participated. The sensitivity to electrically induced pain, heat pain, cold pain, pressure pain and pain inhibition was determined experimentally in each sleep condition. Sleepiness and vigilance were also assessed. Results Night-shift work (NSW) increased the sensitivity to electrically induced pain and heat pain (P≤0.001). Relative to habitual sleep, electrically induced pain increased by 22.3% and heat pain increased by 26.5%. The sensitivity to cold and pressure pain did not change, changes relative to habitual sleep was 0.5). Pain inhibition was 66.9% stronger after NSW versus after habitual sleep (Peffect sizes and may be an important marker for studies comparing the physiological effects of different shift work schedules. Explanations for the differential effect on different pain modalities should be a focus for future studies.

  18. The role of executive functioning in children's attentional pain control: an experimental analysis.

    Science.gov (United States)

    Verhoeven, Katrien; Dick, Bruce; Eccleston, Christopher; Goubert, Liesbet; Crombez, Geert

    2014-02-01

    Directing attention away from pain is often used in children's pain treatment programs to control pain. However, empirical evidence concerning its effectiveness is inconclusive. We therefore sought to understand other influencing factors, including executive function and its role in the pain experience. This study investigates the role of executive functioning in the effectiveness of distraction. School children (n=164) completed executive functioning tasks (inhibition, switching, and working memory) and performed a cold-pressor task. One half of the children simultaneously performed a distracting tone-detection task; the other half did not. Results showed that participants in the distraction group were engaged in the distraction task and were reported to pay significantly less attention to pain than controls. Executive functioning influenced distraction task engagement. More specifically, participants with good inhibition and working memory abilities performed the distraction task better; participants with good switching abilities reported having paid more attention to the distraction task. Furthermore, distraction was found to be ineffective in reducing pain intensity and affect. Executive functioning did not influence the effectiveness of distraction. However, a relationship was found between executive functioning and pain affect, indicating that participants with good inhibition and working memory abilities experienced the cold-pressor task as less stressful and unpleasant. Our findings suggest that distraction as a process for managing pain is complex. While it appears that executive function may play a role in adult distraction, in this study it did not direct attention away from pain. It may instead be involved in the overall pain experience. Copyright © 2013 International Association for the Study of Pain. Published by Elsevier B.V. All rights reserved.

  19. Possible analgesic effect of vigabatrin in animal experimental chronic neuropathic pain Possível efeito analgésico da vigabatrina na dor neuropática crônica experimental animal

    Directory of Open Access Journals (Sweden)

    NILZA D. ALVES

    1999-12-01

    Full Text Available Since anticonvulsants have been used for treating neuralgias, an interest has arisen to experimentally test vigabatrin for its gabaergic mechanism of action. For this, 41 Wistar rats were used, and in 25 of them a constrictive sciatic neuropathy was induced (Bennet & Xie model. For testing pain symptoms, spontaneous (scratching and evoked behaviors to noxious (46o C and non-noxious (40o C thermal stimuli were quantified. Moreover, a comparative pharmacological study of vigabatrin with other analgesic anticonvulsant drugs was also performed. The results showed a possible dose-dependent analgesic effect of vigabatrin (gamma-vinyl-GABA on experimental neuropathic pain, as shown by the significant (pO uso de anticonvulsivantes no tratamento de neuralgias despertou um interesse em testar novas drogas anticonvulsivantes, e dentre essas a vigabatrina por possuir mecanismo de ação gabaérgico. Para isso, foram usados 41 ratos Wistar e em 25 deles induziu-se neuropatia ciática constritiva (modelo de Bennett & Xie. Para testar sintomas de dor, foram quantificados comportamentos espontâneos (coçar-se e evocados, por meio de estímulos térmicos nocivos (46oC e não-nocivos (40oC. Além disso, realizou-se estudo comparativo da vigabatrina com outros anticonvulsivantes analgésicos. Os resultados mostraram um possível efeito analgésico, dose-dependente, de vigabatrina (gama-vinil-GABA em dor neuropática experimental. Isso foi evidenciado pela diminuição significativa (p<0,05 do comportamento de coçar-se e pelo aumento significativo (p<0,05 da latência de retirada da pata posterior direita a estímulos térmicos nocivos. Isso foi corroborado por achados semelhantes em experimentos com anticonvulsivantes (carbamazepina, fenitoína e ácido valpróico analgésicos. Esse possível efeito analgésico da vigabatrina (ainda não descrito na literatura não é mediado pelo sistema opióide.

  20. Pain Intensity Moderates the Relationship Between Age and Pain Interference in Chronic Orofacial Pain Patients.

    Science.gov (United States)

    Boggero, Ian A; Geiger, Paul J; Segerstrom, Suzanne C; Carlson, Charles R

    2015-01-01

    BACKGROUND/STUDY CONTEXT: Chronic pain is associated with increased interference in daily functioning that becomes more pronounced as pain intensity increases. Based on previous research showing that older adults maintain well-being in the face of pain as well as or better than their younger counterparts, the current study examined the interaction of age and pain intensity on interference in a sample of chronic orofacial pain patients. Data were obtained from the records of 508 chronic orofacial pain patients being seen for an initial evaluation from 2008 to 2012. Collected data included age (range: 18-78) and self-reported measures of pain intensity and pain interference. Bivariate correlations and regression models were used to assess for statistical interactions. Regression analyses revealed that pain intensity positively predicted pain interference (R(2) = .35, B = 10.40, SE = 0.62, t(507) = 16.70, p theories, including socioemotional selectivity theory, which posits that as people age, they become more motivated to maximize positive emotions and minimize negative ones. The results highlight the importance of studying the mechanisms older adults use to successfully cope with pain.

  1. Operant conditioning of enhanced pain sensitivity by heat-pain titration.

    Science.gov (United States)

    Becker, Susanne; Kleinböhl, Dieter; Klossika, Iris; Hölzl, Rupert

    2008-11-15

    Operant conditioning mechanisms have been demonstrated to be important in the development of chronic pain. Most experimental studies have investigated the operant modulation of verbal pain reports with extrinsic reinforcement, such as verbal reinforcement. Whether this reflects actual changes in the subjective experience of the nociceptive stimulus remained unclear. This study replicates and extends our previous demonstration that enhanced pain sensitivity to prolonged heat-pain stimulation could be learned in healthy participants through intrinsic reinforcement (contingent changes in nociceptive input) independent of verbal pain reports. In addition, we examine whether different magnitudes of reinforcement differentially enhance pain sensitivity using an operant heat-pain titration paradigm. It is based on the previously developed non-verbal behavioral discrimination task for the assessment of sensitization, which uses discriminative down- or up-regulation of stimulus temperatures in response to changes in subjective intensity. In operant heat-pain titration, this discriminative behavior and not verbal pain report was contingently reinforced or punished by acute decreases or increases in heat-pain intensity. The magnitude of reinforcement was varied between three groups: low (N1=13), medium (N2=11) and high reinforcement (N3=12). Continuous reinforcement was applied to acquire and train the operant behavior, followed by partial reinforcement to analyze the underlying learning mechanisms. Results demonstrated that sensitization to prolonged heat-pain stimulation was enhanced by operant learning within 1h. The extent of sensitization was directly dependent on the received magnitude of reinforcement. Thus, operant learning mechanisms based on intrinsic reinforcement may provide an explanation for the gradual development of sustained hypersensitivity during pain that is becoming chronic.

  2. Central pain processing in chronic tension-type headache

    DEFF Research Database (Denmark)

    Lindelof, Kim; Ellrich, Jens; Jensen, Rigmor

    2009-01-01

    OBJECTIVE: Chronic tension-type headache (CTTH) affects 3% of the population. Directly and indirectly it causes high costs and considerable loss of quality of life. The mechanisms of this disorder are poorly understood and the treatment possibilities are therefore limited. The blink reflex (BR......) reflects neuronal excitability due to nociceptive input in the brainstem. The aim of this study was to investigate nociceptive processing at the level of the brainstem in an experimental pain model of CTTH symptoms. METHODS: The effect of conditioning pain, 5 min infusion of hypertonic saline into the neck...... muscles, was investigated in 20 patients with CTTH and 20 healthy controls. In addition, a pilot study with isotonic saline was performed with 5 subjects in each group. The BR was elicited by electrical stimuli with an intensity of four times the pain threshold, with a superficial concentric electrode. We...

  3. Antinociceptive and anti-exudative synergism between dexketoprofen and tramadol in a model of inflammatory pain in mice.

    Science.gov (United States)

    Miranda, Hugo F; Romero, Maria Asunción; Puig, Margarita M

    2012-06-01

    Preclinical studies have demonstrated antinociceptive synergism between dexketoprofen (DEX) and tramadol (TRM) in acute animal models of nociception. The aim of the present study was to investigate the type of interaction between DEX and TRM in a chronic musculoskeletal pain model in mice, which fairly replicates the characteristics of chronic osteoarticular pain in humans. Inflammation was induced by a subplantar injection of complete Freund's adjuvant (CFA) in male CF1 mice. Nociceptive thresholds were evaluated using the hot plate, the nocifensive spontaneous behavior and the acetone tests, while plasma extravasation (PE) was assessed with Evan's blue. We used the following experimental groups: control (no inflammation), acute (1 day after CFA injection), and chronic inflammation (7 days after CFA). Dose-response curves for DEX and TRM, individually and combined in a 1 : 1 proportion based on their potency were obtained, and the doses that produced a 50% inhibition calculated. The isobolographic analysis revealed that in all groups of study (no inflammation, acute, and chronic inflammation), the combination of DEX : TRM was synergistic, for both the inhibition of nociception and the PE. The results suggest that the DEX : TRM (1 : 1) combination could be useful in the management of acute and chronic inflammatory musculoskeletal pains in humans; in addition, the synergistic interaction between the drugs observed both during acute and chronic inflammation suggests that less doses would be required of each drug to obtain effective analgesia. © 2011 The Authors Fundamental and Clinical Pharmacology © 2011 Société Française de Pharmacologie et de Thérapeutique.

  4. Attenuation of TRPV1 and TRPV4 Expression and Function in Mouse Inflammatory Pain Models Using Electroacupuncture

    Directory of Open Access Journals (Sweden)

    Wei-Hsin Chen

    2012-01-01

    Full Text Available Although pain is a major human affliction, our understanding of pain mechanisms is limited. TRPV1 (transient receptor potential vanilloid subtype 1 and TRPV4 are two crucial receptors involved in inflammatory pain, but their roles in EA- (electroacupuncture- mediated analgesia are unknown. We injected mice with carrageenan (carra or a complete Freund’s adjuvant (CFA to model inflammatory pain and investigated the analgesic effect of EA using animal behavior tests, immunostaining, Western blotting, and a whole-cell recording technique. The inflammatory pain model mice developed both mechanical and thermal hyperalgesia. Notably, EA at the ST36 acupoint reversed these phenomena, indicating its curative effect in inflammatory pain. The protein levels of TRPV1 and TRPV4 in DRG (dorsal root ganglion neurons were both increased at day 4 after the initiation of inflammatory pain and were attenuated by EA, as demonstrated by immunostaining and Western blot analysis. We verified DRG electrophysiological properties to confirm that EA ameliorated peripheral nerve hyperexcitation. Our results indicated that the AP (action potential threshold, rise time, and fall time, and the percentage and amplitude of TRPV1 and TRPV4 were altered by EA, indicating that EA has an antinociceptive role in inflammatory pain. Our results demonstrate a novel role for EA in regulating TRPV1 and TRPV4 protein expression and nerve excitation in mouse inflammatory pain models.

  5. The effects of music therapy on pain in patients with neuropathic pain.

    Science.gov (United States)

    Korhan, Esra Akın; Uyar, Meltem; Eyigör, Can; Hakverdioğlu Yönt, Gülendam; Çelik, Serkan; Khorshıd, Leyla

    2014-03-01

    The aim of this study was to investigate the effect of relaxing music on pain intensity in patients with neuropathic pain. A quasi-experimental study, repeated measures design was used. Thirty patients, aged 18-70 years, with neuropathic pain and hospitalized in an Algology clinic were identified as a convenience sample. Participants received 60 minutes of music therapy. Classical Turkish music was played to patients using a media player (MP3) and headphones. Participants had pain scores taken immediately before the intervention and at the 30th and 60th minutes of the intervention. Data were collected over a 6-month period in 2012. The patients' mean pain intensity scores were reduced by music, and that decrease was progressive over the 30th and 60th minutes of the intervention, indicating a cumulative dose effect. The results of this study implied that the inclusion of music therapy in the routine care of patients with neuropathic pain could provide nurses with an effective practice for reducing patients' pain intensity. Copyright © 2014 American Society for Pain Management Nursing. Published by Elsevier Inc. All rights reserved.

  6. Effects of noxious stimulation and pain expectations on neuromuscular control of the spine in patients with chronic low back pain.

    Science.gov (United States)

    Henchoz, Yves; Tétreau, Charles; Abboud, Jacques; Piché, Mathieu; Descarreaux, Martin

    2013-10-01

    Alterations of the neuromuscular control of the lumbar spine have been reported in patients with chronic low back pain (LBP). During trunk flexion and extension tasks, the reduced myoelectric activity of the low back extensor musculature observed during full trunk flexion is typically absent in patients with chronic LBP. To determine whether pain expectations could modulate neuromuscular responses to experimental LBP to a higher extent in patients with chronic LBP compared with controls. A cross-sectional, case-control study. Twenty-two patients with nonspecific chronic LBP and 22 age- and sex-matched control participants. Trunk flexion-extension tasks were performed under three experimental conditions: innocuous heat, noxious stimulation with low pain expectation, and noxious stimulation with high pain expectation. Noxious stimulations were delivered using a contact heat thermode applied on the skin of the lumbar region (L4-L5), whereas low or high pain expectations were induced by verbal and visual instructions. Surface electromyography of erector spinae at L2-L3 and L4-L5, as well as lumbopelvic kinematic variables were collected during the tasks. Pain was evaluated using a numerical rating scale. Pain catastrophizing, disability, anxiety, and fear-avoidance beliefs were measured using validated questionnaires. Two-way mixed analysis of variance revealed that pain was significantly different among the three experimental conditions (F2,84=317.5; plow back extensor musculature during full trunk flexion was observed in the high compared with low pain expectations condition at the L2-L3 level (F2,84=9.5; ppain catastrophizing in patients with chronic LBP (r=0.54; p=.012). Repeated exposure to pain appears to generate rigid and less variable patterns of muscle activation in patients with chronic LBP, which attenuate their response to pain expectations. Patients with high levels of pain catastrophizing show higher myoelectric activity of lumbar muscles in full flexion

  7. Reward and motivation in pain and pain relief

    Science.gov (United States)

    Navratilova, Edita; Porreca, Frank

    2015-01-01

    Pain is fundamentally unpleasant, a feature that protects the organism by promoting motivation and learning. Relief of aversive states, including pain, is rewarding. The aversiveness of pain, as well as the reward from relief of pain, is encoded by brain reward/motivational mesocorticolimbic circuitry. In this Review, we describe current knowledge of the impact of acute and chronic pain on reward/motivation circuits gained from preclinical models and from human neuroimaging. We highlight emerging clinical evidence suggesting that anatomical and functional changes in these circuits contribute to the transition from acute to chronic pain. We propose that assessing activity in these conserved circuits can offer new outcome measures for preclinical evaluation of analgesic efficacy to improve translation and speed drug discovery. We further suggest that targeting reward/motivation circuits may provide a path for normalizing the consequences of chronic pain to the brain, surpassing symptomatic management to promote recovery from chronic pain. PMID:25254980

  8. Pain evaluation in self and others in autism spectrum disorder

    DEFF Research Database (Denmark)

    Thaler, Hanna; Skewes, Joshua; Gebauer, Line

    The picture of pain sensation in autism and its relationship with perception of pain in others is currently far from clear. A common observation in case studies is that autistic individuals are more pain insensitive. However, this hypothesis has recently been challenged by experimental evidence...... indicating that physiological sensitivity in autism may even be enhanced. Evaluation of own pain might also relate to one’s ability to evaluate pain in others. There is some experimental evidence indicating that people generally tend to underestimate how much pain another person feels. Our study investigated...... whether this underestimation bias is stronger in individuals with autism and how this evaluation may be associated with one’s individual pain sensitivity. Using electric pain stimulation, we tested whether autistic and non-autistic male adults (n = 16 in each group) rated the intensity and unpleasantness...

  9. DEET potentiates the development and persistence of anticholinesterase dependent chronic pain signs in a rat model of Gulf War Illness pain

    International Nuclear Information System (INIS)

    Flunker, L.K.; Nutter, T.J.; Johnson, R.D.; Cooper, B.Y.

    2017-01-01

    Exposure to DEET (N,N-diethyl-meta-toluamide) may have influenced the pattern of symptoms observed in soldiers with GWI (Gulf War Illness; Haley and Kurt, 1997). We examined how the addition of DEET (400 mg/kg; 50% topical) to an exposure protocol of permethrin (2.6 mg/kg; topical), chlorpyrifos (CP; 120 mg/kg), and pyridostigmine bromide (PB;13 mg/kg) altered the emergence and pattern of pain signs in an animal model of GWI pain (). Rats underwent behavioral testing before, during and after a 4 week exposure: 1) hindlimb pressure withdrawal threshold; 2) ambulation (movement distance and rate); and 3) resting duration. Additional studies were conducted to assess the influence of acute DEET (10–100 μM) on muscle and vascular nociceptor K v 7, K DR , Na v 1.8 and Na v 1.9. We report that a 50% concentration of DEET enhanced the development and persistence of pain-signs. Rats exposed to all 4 compounds exhibited ambulation deficits that appeared 5–12 weeks post-exposure and persisted through weeks 21–24. Rats exposed to only three agents (CP or PB excluded), did not fully develop ambulation deficits. When PB was excluded, rats also developed rest duration pain signs, in addition to ambulation deficits. There was no evidence that physiological doses of DEET acutely modified nociceptor K v 7, K DR , Na v 1.8 or Na v 1.9 activities. Nevertheless, DEET augmented protocols decreased the conductance of K v 7 expressed in vascular nociceptors harvested from chronically exposed rats. We concluded that DEET enhanced the development and persistence of pain behaviors, but the anticholinesterases CP and PB played a determinant role. - Highlights: • DEET accelerated and prolonged pain-like behaviors in a rat model of Gulf War Illness. • The development of pain behaviors were dependent upon chlorpyrifos and pyridostigmine. • Conductance of vascular nociceptor Kv7 was diminished 12 weeks following exposures. • DEET did not have any acute influence on nociceptor Kv7

  10. Effect of peripheral morphine in a human model of acute inflammatory pain

    DEFF Research Database (Denmark)

    Lillesø, J; Hammer, N A; Pedersen, J L

    2000-01-01

    Several studies have demonstrated the presence of opioid inducible receptors on peripheral nerves and peripheral antinociceptive effects of opioids. However, the effects of peripheral opioid administration in man are controversial. Our study used a randomized, double-blind, placebo-controlled, th......Several studies have demonstrated the presence of opioid inducible receptors on peripheral nerves and peripheral antinociceptive effects of opioids. However, the effects of peripheral opioid administration in man are controversial. Our study used a randomized, double-blind, placebo......-controlled, three-way crossover design in a human model of acute inflammatory pain (heat injury). We studied 18 healthy volunteers who each received morphine locally (2 mg), morphine systemically (2 mg), or placebo on three separate study days. The subjects received morphine infiltration subcutaneously (s.c.). 1 h......, but local morphine infiltration neither reduced pain during the burn, nor primary or secondary hyperalgesia to mechanical and heat stimuli after the burn. In conclusion, peripherally applied morphine had no acute antinociceptive effects in this human model of acute inflammatory pain....

  11. The structural model of pain, cognitive strategies, and negative emotions in functional gastrointestinal disorders

    Directory of Open Access Journals (Sweden)

    Mina Mazaheri

    2016-01-01

    Full Text Available Background: Patients with functional gastrointestinal disorders (FGIDs may use specific coping strategies. We intend to provide a mediating role of the relationship between pain (intensity and acceptance, cognitive emotion regulation strategies, and negative emotions in patients with FGIDs. Materials and Methods: Participants were 176 inpatients, all experiencing significant FGIDs symptomatology as confirmed by gastroenterologists. Patients completed data on cognitive emotion regulation questionnaire, short form of depression, anxiety, stress scale, chronic pain acceptance questionnaire-revised, and pain intensity scale. Data were analyzed using structural equation modeling method. Results: The pain intensity had significantly direct effect on cognitive emotion regulation strategies and indirect effect on negative emotions. Besides, the mediating role of negative emotions in the relationship between the strategies and pain acceptance were supported, whereas indirect relationships between pain intensity and acceptance through cognitive strategies were not confirmed. Conclusion: The results of the study emphasize the role of pain intensity in the development of negative emotions through cognitive strategies and the role of the strategies in pain acceptance through negative emotions. In fact, cognitive strategies to be related to pain and emotions.

  12. Clinical Prediction Model and Tool for Assessing Risk of Persistent Pain After Breast Cancer Surgery

    DEFF Research Database (Denmark)

    Meretoja, Tuomo J; Andersen, Kenneth Geving; Bruce, Julie

    2017-01-01

    are missing. The aim was to develop a clinically applicable risk prediction tool. Methods The prediction models were developed and tested using three prospective data sets from Finland (n = 860), Denmark (n = 453), and Scotland (n = 231). Prediction models for persistent pain of moderate to severe intensity......), high body mass index ( P = .039), axillary lymph node dissection ( P = .008), and more severe acute postoperative pain intensity at the seventh postoperative day ( P = .003) predicted persistent pain in the final prediction model, which performed well in the Danish (ROC-AUC, 0.739) and Scottish (ROC......-AUC, 0.740) cohorts. At the 20% risk level, the model had 32.8% and 47.4% sensitivity and 94.4% and 82.4% specificity in the Danish and Scottish cohorts, respectively. Conclusion Our validated prediction models and an online risk calculator provide clinicians and researchers with a simple tool to screen...

  13. Improving pain care through implementation of the Stepped Care Model at a multisite community health center

    Directory of Open Access Journals (Sweden)

    Anderson DR

    2016-11-01

    Full Text Available Daren R Anderson,1 Ianita Zlateva,1 Emil N Coman,2 Khushbu Khatri,1 Terrence Tian,1 Robert D Kerns3 1Weitzman Institute, Community Health Center, Inc., Middletown, 2UCONN Health Disparities Institute, University of Connecticut, Farmington, 3VA Connecticut Healthcare System, West Haven, CT, USA Purpose: Treating pain in primary care is challenging. Primary care providers (PCPs receive limited training in pain care and express low confidence in their knowledge and ability to manage pain effectively. Models to improve pain outcomes have been developed, but not formally implemented in safety net practices where pain is particularly common. This study evaluated the impact of implementing the Stepped Care Model for Pain Management (SCM-PM at a large, multisite Federally Qualified Health Center. Methods: The Promoting Action on Research Implementation in Health Services framework guided the implementation of the SCM-PM. The multicomponent intervention included: education on pain care, new protocols for pain assessment and management, implementation of an opioid management dashboard, telehealth consultations, and enhanced onsite specialty resources. Participants included 25 PCPs and their patients with chronic pain (3,357 preintervention and 4,385 postintervention cared for at Community Health Center, Inc. Data were collected from the electronic health record and supplemented by chart reviews. Surveys were administered to PCPs to assess knowledge, attitudes, and confidence. Results: Providers’ pain knowledge scores increased to an average of 11% from baseline; self-rated confidence in ability to manage pain also increased. Use of opioid treatment agreements and urine drug screens increased significantly by 27.3% and 22.6%, respectively. Significant improvements were also noted in documentation of pain, pain treatment, and pain follow-up. Referrals to behavioral health providers for patients with pain increased by 5.96% (P=0.009. There was no

  14. Quantifying and Characterizing Tonic Thermal Pain Across Subjects From EEG Data Using Random Forest Models.

    Science.gov (United States)

    Vijayakumar, Vishal; Case, Michelle; Shirinpour, Sina; He, Bin

    2017-12-01

    Effective pain assessment and management strategies are needed to better manage pain. In addition to self-report, an objective pain assessment system can provide a more complete picture of the neurophysiological basis for pain. In this study, a robust and accurate machine learning approach is developed to quantify tonic thermal pain across healthy subjects into a maximum of ten distinct classes. A random forest model was trained to predict pain scores using time-frequency wavelet representations of independent components obtained from electroencephalography (EEG) data, and the relative importance of each frequency band to pain quantification is assessed. The mean classification accuracy for predicting pain on an independent test subject for a range of 1-10 is 89.45%, highest among existing state of the art quantification algorithms for EEG. The gamma band is the most important to both intersubject and intrasubject classification accuracy. The robustness and generalizability of the classifier are demonstrated. Our results demonstrate the potential of this tool to be used clinically to help us to improve chronic pain treatment and establish spectral biomarkers for future pain-related studies using EEG.

  15. Pain genes.

    Directory of Open Access Journals (Sweden)

    Tom Foulkes

    2008-07-01

    Full Text Available Pain, which afflicts up to 20% of the population at any time, provides both a massive therapeutic challenge and a route to understanding mechanisms in the nervous system. Specialised sensory neurons (nociceptors signal the existence of tissue damage to the central nervous system (CNS, where pain is represented in a complex matrix involving many CNS structures. Genetic approaches to investigating pain pathways using model organisms have identified the molecular nature of the transducers, regulatory mechanisms involved in changing neuronal activity, as well as the critical role of immune system cells in driving pain pathways. In man, mapping of human pain mutants as well as twin studies and association studies of altered pain behaviour have identified important regulators of the pain system. In turn, new drug targets for chronic pain treatment have been validated in transgenic mouse studies. Thus, genetic studies of pain pathways have complemented the traditional neuroscience approaches of electrophysiology and pharmacology to give us fresh insights into the molecular basis of pain perception.

  16. Endogenous Pain Modulation Induced by Extrinsic and Intrinsic Psychological Threat in Healthy Individuals.

    Science.gov (United States)

    Gibson, William; Moss, Penny; Cheng, Tak Ho; Garnier, Alexandre; Wright, Anthony; Wand, Benedict M

    2018-03-01

    Many factors interact to influence threat perception and the subsequent experience of pain. This study investigated the effect of observing pain (extrinsic threat) and intrinsic threat of pain to oneself on pressure pain threshold (PPT). Forty socially connected pairs of healthy volunteers were threat-primed and randomly allocated to experimental or control roles. An experimental pain modulation paradigm was applied, with non-nociceptive threat cues used as conditioning stimuli. In substudy 1, the extrinsic threat to the experimental participant was observation of the control partner in pain. The control participant underwent hand immersion in noxious and non-noxious water baths in randomized order. Change in the observing participant's PPT from baseline to mid- and postimmersion was calculated. A significant interaction was found for PPT between conditions and test time (F 2,78  = 24.9, P Extrinsic and intrinsic threat of pain, in the absence of any afferent input therefore influences pain modulation. This may need to be considered in studies that use noxious afferent input with populations who show dysfunctional pain modulation. The effect on endogenous analgesia of observing another's pain and of threat of pain to oneself was investigated. Extrinsic as well as intrinsic threat cues, in the absence of any afferent input, increased pain thresholds, suggesting that mere threat of pain may initiate analgesic effects in traditional noxious experimental paradigms. Copyright © 2017 The American Pain Society. Published by Elsevier Inc. All rights reserved.

  17. The effects of anger and sadness on clinical pain reports and experimentally-induced pain thresholds in women with and without fibromyalgia.

    NARCIS (Netherlands)

    Middendorp, H. van; Lumley, M.A.; Jacobs, J.W.G.; Bijlsma, J.W.J.; Geenen, R.

    2010-01-01

    OBJECTIVE: Negative emotions are commonly experienced in fibromyalgia and may affect pain. This study examined the effects of anger and sadness on clinical pain reports and on pain threshold and tolerance in response to electrical stimulation in women with and without fibromyalgia. METHODS: In an

  18. The effects of patient-professional partnerships on the self-management and health outcomes for patients with chronic back pain : a quasi-experimental study

    OpenAIRE

    Fu, Yu; Yu, Ge; McNichol, Elaine; Marczewski, Kath; Closs, S. José

    2016-01-01

    Background: Self-management may be a lifelong task for patients with chronic back pain. Research suggests that chronic pain self-management programmes have beneficial effects on patients? health outcome. Contemporary pain management theories and models also suggest that a good patient-professional partnership enhances patients? ability to self-manage their condition.

  19. Cognitive bias in back pain patients attending osteopathy: testing the enmeshment model in reference to future thinking.

    Science.gov (United States)

    Read, Jessica; Pincus, Tamar

    2004-12-01

    Depressive symptoms are common in chronic pain. Previous research has found differences in information-processing biases in depressed pain patients and depressed people without pain. The schema enmeshment model of pain (SEMP) has been proposed to explain chronic pain patients' information-processing biases. Negative future thinking is common in depression but has not been explored in relation to chronic pain and information-processing models. The study aimed to test the SEMP with reference to future thinking. An information-processing paradigm compared endorsement and recall bias between depressed and non-depressed chronic low back pain patients and control participants. Twenty-five depressed and 35 non-depressed chronic low back pain patients and 25 control participants (student osteopaths) were recruited from an osteopathy practice. Participants were asked to endorse positive and negative ill-health, depression-related, and neutral (control) adjectives, encoded in reference to either current or future time-frame. Incidental recall of the adjectives was then tested. While the expected hypothesis of a recall bias by depressed pain patients towards ill-health stimuli in the current condition was confirmed, the recall bias was not present in the future condition. Additionally, patterns of endorsement and recall bias differed. Results extend understanding of future thinking in chronic pain within the context of the SEMP.

  20. Longitudinal Structural and Functional Brain Network Alterations in a Mouse Model of Neuropathic Pain.

    Science.gov (United States)

    Bilbao, Ainhoa; Falfán-Melgoza, Claudia; Leixner, Sarah; Becker, Robert; Singaravelu, Sathish Kumar; Sack, Markus; Sartorius, Alexander; Spanagel, Rainer; Weber-Fahr, Wolfgang

    2018-04-22

    Neuropathic pain affects multiple brain functions, including motivational processing. However, little is known about the structural and functional brain changes involved in the transition from an acute to a chronic pain state. Here we combined behavioral phenotyping of pain thresholds with multimodal neuroimaging to longitudinally monitor changes in brain metabolism, structure and connectivity using the spared nerve injury (SNI) mouse model of chronic neuropathic pain. We investigated stimulus-evoked pain responses prior to SNI surgery, and one and twelve weeks following surgery. A progressive development and potentiation of stimulus-evoked pain responses (cold and mechanical allodynia) were detected during the course of pain chronification. Voxel-based morphometry demonstrated striking decreases in volume following pain induction in all brain sites assessed - an effect that reversed over time. Similarly, all global and local network changes that occurred following pain induction disappeared over time, with two notable exceptions: the nucleus accumbens, which played a more dominant role in the global network in a chronic pain state and the prefrontal cortex and hippocampus, which showed lower connectivity. These changes in connectivity were accompanied by enhanced glutamate levels in the hippocampus, but not in the prefrontal cortex. We suggest that hippocampal hyperexcitability may contribute to alterations in synaptic plasticity within the nucleus accumbens, and to pain chronification. Copyright © 2018 The Authors. Published by Elsevier Ltd.. All rights reserved.

  1. Developing a model for measuring fear of pain in Norwegian samples: The Fear of Pain Questionnaire Norway

    DEFF Research Database (Denmark)

    Vambheim, Sara M; Lyby, Peter Solvoll; Aslaksen, Per M

    2017-01-01

    Fear of pain is highly correlated with pain report and physiological measures of arousal when pain is inflicted. The Fear of Pain Questionnaire III (FPQ-III) and The Fear of Pain Questionnaire Short Form (FPQ-SF) are self-report inventories developed for assessment of fear of pain (FOP). A previous...

  2. Nerve Regenerative Effects of GABA-B Ligands in a Model of Neuropathic Pain

    Directory of Open Access Journals (Sweden)

    Valerio Magnaghi

    2014-01-01

    Full Text Available Neuropathic pain arises as a direct consequence of a lesion or disease affecting the peripheral somatosensory system. It may be associated with allodynia and increased pain sensitivity. Few studies correlated neuropathic pain with nerve morphology and myelin proteins expression. Our aim was to test if neuropathic pain is related to nerve degeneration, speculating whether the modulation of peripheral GABA-B receptors may promote nerve regeneration and decrease neuropathic pain. We used the partial sciatic ligation- (PSL- induced neuropathic model. The biochemical, morphological, and behavioural outcomes of sciatic nerve were analysed following GABA-B ligands treatments. Simultaneous 7-days coadministration of baclofen (10 mg/kg and CGP56433 (3 mg/kg alters tactile hypersensitivity. Concomitantly, specific changes of peripheral nerve morphology, nerve structure, and myelin proteins (P0 and PMP22 expression were observed. Nerve macrophage recruitment decreased and step coordination was improved. The PSL-induced changes in nociception correlate with altered nerve morphology and myelin protein expression. Peripheral synergic effects, via GABA-B receptor activation, promote nerve regeneration and likely ameliorate neuropathic pain.

  3. Contextual influences on pain communication in couples with and without a partner with chronic pain.

    Science.gov (United States)

    Gagnon, Michelle M; Hadjistavropoulos, Thomas; MacNab, Ying C

    2017-10-01

    This is an experimental study of pain communication in couples. Despite evidence that chronic pain in one partner impacts both members of the dyad, dyadic influences on pain communication have not been sufficiently examined and are typically studied based on retrospective reports. Our goal was to directly study contextual influences (ie, presence of chronic pain, gender, relationship quality, and pain catastrophizing) on self-reported and nonverbal (ie, facial expressions) pain responses. Couples with (n = 66) and without (n = 65) an individual with chronic pain (ICP) completed relationship and pain catastrophizing questionnaires. Subsequently, one partner underwent a pain task (pain target, PT), while the other partner observed (pain observer, PO). In couples with an ICP, the ICP was assigned to be the PT. Pain intensity and PO perceived pain intensity ratings were recorded at multiple intervals. Facial expressions were video recorded throughout the pain task. Pain-related facial expression was quantified using the Facial Action Coding System. The most consistent predictor of either partner's pain-related facial expression was the pain-related facial expression of the other partner. Pain targets provided higher pain ratings than POs and female PTs reported and showed more pain, regardless of chronic pain status. Gender and the interaction between gender and relationship satisfaction were predictors of pain-related facial expression among PTs, but not POs. None of the examined variables predicted self-reported pain. Results suggest that contextual variables influence pain communication in couples, with distinct influences for PTs and POs. Moreover, self-report and nonverbal responses are not displayed in a parallel manner.

  4. Effects of a home-exercise therapy programme on cervical and lumbar range of motion among nurses with neck and lower back pain: a quasi-experimental study.

    Science.gov (United States)

    Freimann, Tiina; Merisalu, Eda; Pääsuke, Mati

    2015-01-01

    Cervical and lumbar range of motion limitations are usually associated with musculoskeletal pain in the neck and lower back, and are a major health problem among nurses. Physical exercise has been evaluated as an effective intervention method for improving cervical and lumbar range of motion, and for preventing and reducing musculoskeletal pain. The purpose of this study was to investigate the effects of a home-exercise therapy programme on cervical and lumbar range of motion among intensive care unit nurses who had experienced mild to moderate musculoskeletal pain in the neck and or lower back during the previous six months. A quasi-experimental study was conducted among intensive care unit nurses at Tartu University Hospital (Estonia) between May and July 2011. Thirteen nurses who had suffered musculoskeletal pain episodes in the neck and or lower back during the previous six months underwent an 8-week home-exercise therapy programme. Eleven nurses without musculoskeletal pain formed a control group. Questions from the Nordic Musculoskeletal Questionnaire and the 11-point Visual Analogue Scale were used to select potential participants for the experimental group via an assessment of the prevalence and intensity of musculoskeletal pain. Cervical range of motion and lumbar range of motion in flexion, extension, lateral flexion and (cervical range of motion only) rotation were measured with a digital goniometer. A paired t-test was used to compare the measured parameters before and after the home-exercise therapy programme. A Student's t-test was used to analyse any differences between the experimental and control groups. After the home-exercise therapy, there was a significant increase (p cervical range of motion in flexion, extension, lateral flexion and rotation, and in lumbar range of motion in lateral flexion. Cervical range of motion in flexion was significantly higher (p cervical and lumbar range of motion among intensive care nurses. Further studies are

  5. A review of the evidence regarding associations between attachment theory and experimentally induced pain.

    Science.gov (United States)

    Meredith, Pamela Joy

    2013-04-01

    Theoretical and empirical evidence suggests that adult attachment and pain-related variables are predictably and consistently linked, and that understanding these links may guide pain intervention and prevention efforts. In general, insecure attachment has been portrayed as a risk factor, and secure attachment as a protective factor, for people with chronic pain conditions. In an effort to better understand the relationships among attachment and pain variables, these links have been investigated in pain-free samples using induced-pain techniques. The present paper reviews the available research linking adult attachment and laboratory-induced pain. While the diverse nature of the studies precludes definitive conclusions, together these papers offer support for associations between insecure attachment and a more negative pain experience. The evidence presented in this review highlights areas for further empirical attention, as well as providing some guidance for clinicians who may wish to employ preventive approaches and other interventions informed by attachment theory.

  6. Comparing the Effectiveness of Cognitive Behavioral Therapy and Hypnosis Therapy Pain Self-Efficacy and Pain Severity in Girls with Primary Dysmenorrhea

    OpenAIRE

    F Farshbaf Manei Sefat; A Abolghasemi; U Barahmand; N Hajloo

    2017-01-01

    ABSTRACT   Background & aim: Menstruation as an important issue in adolescence and menstrual pain is a common problem in adolescents. Regarding the relationship between pain severity and  pain self-efficacy, this study aimed to investigate and compare the efficacy of cognitive-behavioral therapy and hypnosis therapy on pain and pain self-efficacy in girls with primary dysmenorrhea.   Methods: The method of research is Quasi experimental and research design is pretes...

  7. The influence of children's pain memories on subsequent pain experience.

    Science.gov (United States)

    Noel, Melanie; Chambers, Christine T; McGrath, Patrick J; Klein, Raymond M; Stewart, Sherry H

    2012-08-01

    Healthy children are often required to repeatedly undergo painful medical procedures (eg, immunizations). Although memory is often implicated in children's reactions to future pain, there is a dearth of research directly examining the relationship between the 2. The current study investigated the influence of children's memories for a novel pain stimulus on their subsequent pain experience. One hundred ten healthy children (60 boys) between the ages of 8 and 12 years completed a laboratory pain task and provided pain ratings. Two weeks later, children provided pain ratings based on their memories as well as their expectancies about future pain. One month following the initial laboratory visit, children again completed the pain task and provided pain ratings. Results showed that children's memory of pain intensity was a better predictor of subsequent pain reporting than their actual initial reporting of pain intensity, and mediated the relationship between initial and subsequent pain reporting. Children who had negatively estimated pain memories developed expectations of greater pain prior to a subsequent pain experience and showed greater increases in pain ratings over time than children who had accurate or positively estimated pain memories. These findings highlight the influence of pain memories on healthy children's expectations of future pain and subsequent pain experiences and extend predictive models of subsequent pain reporting. Copyright © 2012 International Association for the Study of Pain. Published by Elsevier B.V. All rights reserved.

  8. Do pain-associated contexts increase pain sensitivity? An investigation using virtual reality.

    Science.gov (United States)

    Harvie, Daniel S; Sterling, Michele; Smith, Ashley D

    2018-04-30

    Pain is not a linear result of nociception, but is dependent on multisensory inputs, psychological factors, and prior experience. Since nociceptive models appear insufficient to explain chronic pain, understanding non-nociceptive contributors is imperative. Several recent models propose that cues associatively linked to painful events might acquire the capacity to augment, or even cause, pain. This experiment aimed to determine whether contexts associated with pain, could modulate mechanical pain thresholds and pain intensity. Forty-eight healthy participants underwent a contextual conditioning procedure, where three neutral virtual reality contexts were paired with either unpredictable noxious stimulation, unpredictable vibrotactile stimulation, or no stimulation. Following the conditioning procedure, mechanical pain thresholds and pain evoked by a test stimulus were examined in each context. In the test phase, the effect of expectancy was equalised across conditions by informing participants when thresholds and painful stimuli would be presented. Contrary to our hypothesis, scenes that were associated with noxious stimulation did not increase mechanical sensitivity (p=0.08), or increase pain intensity (p=0.46). However, an interaction with sex highlighted the possibility that pain-associated contexts may alter pain sensitivity in females but not males (p=0.03). Overall, our data does not support the idea that pain-associated contexts can alter pain sensitivity in healthy asymptomatic individuals. That an effect was shown in females highlights the possibility that some subgroups may be susceptible to such an effect, although the magnitude of the effect may lack real-world significance. If pain-associated cues prove to have a relevant pain augmenting effect, in some subgroups, procedures aimed at extinguishing pain-related associations may have therapeutic potential.

  9. Usefulness of the Pain Tracking Technique in Acute Mechanical Low Back Pain

    Directory of Open Access Journals (Sweden)

    Tania Bravo Acosta

    2015-01-01

    Full Text Available Objective. To evaluate the usefulness of the pain tracking technique in acute mechanical low back pain. Method. We performed an experimental prospective (longitudinal explanatory study between January 2011 and September 2012. The sample was randomly divided into two groups. Patients were assessed at the start and end of the treatment using the visual analogue scale and the Waddell test. Treatment consisted in applying the pain tracking technique to the study group and interferential current therapy to the control group. At the end of treatment, cryotherapy was applied for 10 minutes. The Wilcoxon signed-rank test and the Mann Whitney test were used. They were performed with a predetermined significance level of p≤0.05. Results. Pain was triggered by prolonged static posture and intense physical labor and intensified through trunk movements and when sitting and standing. The greatest relief was reported in lateral decubitus position and in William’s position. The majority of the patients had contracture. Pain and disability were modified with the rehabilitation treatment in both groups. Conclusions. Both the pain tracking and interferential current techniques combined with cryotherapy are useful treatments for acute mechanical low back pain. The onset of analgesia is faster when using the pain tracking technique.

  10. Evaluation of the Effect of Duration on the Efficacy of Pulsed Radiofrequency in an Animal Model of Neuropathic Pain.

    Science.gov (United States)

    Ramzy, Eiad A; Khalil, Khaled I; Nour, Eman M; Hamed, Mohammed F; Taha, Mohamed A

    2018-03-01

    Pulsed radiofrequency (PRF) is increasingly used in clinical practice, especially in neuropathic pain disorders. Although PRF is not new to clinical use, there are significant gaps in knowledge regarding its effectiveness. The current study was conducted to evaluate the effect of duration of application of PRF on its analgesic efficacy in improvement of neuropathic pain. A randomized experimental trial. An animal research facility at the College of Veterinary Medicine at Mansoura University in Egypt. Chronic constriction of the sciatic nerve of 36 male Sprague-Dawley rats was performed to induce neuropathic pain. The rats were divided into 6 groups (6 rats each) in which PRF was applied for 2, 4, 6, or 8 minutes or not at all. In one group, RF cannula was applied without performing PRF intervention. The pain was assessed through observation of resting paw posture (RPP) at 3, 10, and 21 days. Nerve damage was assessed by histopathological evaluation of the sciatic nerve. Immunohistochemical localization of proinflammatory cytokines (interleukin 6 [IL-6] and tumor necrosis factor alpha [TNF-alpha]) was also done. RPP was improved in rats treated with PRF. This improvement was significant only in rats treated for 8 minutes. Increased duration for PRF application was associated with a significant decrease in IL-6 and TNF-alpha contents in all groups when compared with the control group. Histopathological evaluation of the constricted sciatic nerve revealed no statistical significance among the different study groups. The study was limited by the lack of measurement of other inflammatory markers that may help elucidate other relevant mechanisms. Increased duration of PRF application resulted in better analgesic efficacy without any increase in tissue injury in an animal model of neuropathic pain. This effect may be attributed to decreased production of pro-inflammatory cytokines. Pulsed radiofrequency, analgesic, rats, sciatic nerve, duration, neuropathic pain.

  11. A surgical ankle sprain pain model in the rat: Effects of morphine and indomethacin

    OpenAIRE

    Young Kim, Hee; Wang, Jigong; Chung, Kyungsoon; Mo Chung, Jin

    2008-01-01

    Ankle sprain is a frequent injury in humans that results in pain, swelling and difficulty in walking on the affected ankle. Currently a suitable animal model resembling human ankle sprain is lacking. Here, we describe an animal ankle sprain model induced by ankle ligament injury (ALI) in rats. Cutting combinations of the lateral ankle ligament complex produced pain, edema and difficulty of weight bearing, thereby mimicking severe (grade III) ankle sprain in humans. Analgesic compounds, morphi...

  12. Mindfulness meditation-related pain relief: Evidence for unique brain mechanisms in the regulation of pain

    Science.gov (United States)

    Zeidan, F.; Grant, J.A.; Brown, C.A.; McHaffie, J.G.; Coghill, R.C.

    2013-01-01

    The cognitive modulation of pain is influenced by a number of factors ranging from attention, beliefs, conditioning, expectations, mood, and the regulation of emotional responses to noxious sensory events. Recently, mindfulness meditation has been found attenuate pain through some of these mechanisms including enhanced cognitive and emotional control, as well as altering the contextual evaluation of sensory events. This review discusses the brain mechanisms involved in mindfulness meditation-related pain relief across different meditative techniques, expertise and training levels, experimental procedures, and neuroimaging methodologies. Converging lines of neuroimaging evidence reveal that mindfulness meditation-related pain relief is associated with unique appraisal cognitive processes depending on expertise level and meditation tradition. Moreover, it is postulated that mindfulness meditation-related pain relief may share a common final pathway with other cognitive techniques in the modulation of pain. PMID:22487846

  13. The Development of a Technology-Based Hierarchy to Assess Chronic Low Back Pain and Pain-Related Anxiety From a Fear-Avoidance Model.

    Science.gov (United States)

    Springer, Kristen S; George, Steven Z; Robinson, Michael E

    2016-08-01

    Previous studies have not examined the assessment of chronic low back pain (CLBP) and pain-related anxiety from a fear avoidance model through the use of motion-capture software and virtual human technologies. The aim of this study was to develop and assess the psychometric properties of an interactive, technologically based hierarchy that can be used to assess patients with pain and pain-related anxiety. We enrolled 30 licensed physical therapists and 30 participants with CLBP. Participants rated 21 video clips of a 3-D animated character (avatar) engaging in activities that are typically feared by patients with CLBP. The results of the study indicate that physical therapists found the virtual hierarchy clips acceptable and depicted realistic patient experiences. Most participants with CLBP reported at least 1 video clip as being sufficiently anxiety-provoking for use clinically. Therefore, this study suggests a hierarchy of fears can be created out of 21 virtual patient video clips paving the way for future clinical use in patients with CLBP. This report describes the development of a computer-based virtual patient system for the assessment of back pain-related fear and anxiety. Results show that people with back pain as well as physical therapists found the avatar to be realistic, and the depictions of behavior anxiety- and fear-provoking. Copyright © 2016 American Pain Society. Published by Elsevier Inc. All rights reserved.

  14. Topical combinations aimed at treating microvascular dysfunction reduce allodynia in rat models of CRPS-I and neuropathic pain.

    Science.gov (United States)

    Ragavendran, J Vaigunda; Laferrière, André; Xiao, Wen Hua; Bennett, Gary J; Padi, Satyanarayana S V; Zhang, Ji; Coderre, Terence J

    2013-01-01

    Growing evidence indicates that various chronic pain syndromes exhibit tissue abnormalities caused by microvasculature dysfunction in the blood vessels of skin, muscle, or nerve. We tested whether topical combinations aimed at improving microvascular function would relieve allodynia in animal models of complex regional pain syndrome type I (CRPS-I) and neuropathic pain. We hypothesized that topical administration of either α(2)-adrenergic (α(2)A) receptor agonists or nitric oxide (NO) donors combined with either phosphodiesterase (PDE) or phosphatidic acid (PA) inhibitors would effectively reduce allodynia in these animal models of chronic pain. Single topical agents produced significant dose-dependent antiallodynic effects in rats with chronic postischemia pain, and the antiallodynic dose-response curves of PDE and PA inhibitors were shifted 2.5- to 10-fold leftward when combined with nonanalgesic doses of α(2)A receptor agonists or NO donors. Topical combinations also produced significant antiallodynic effects in rats with sciatic nerve injury, painful diabetic neuropathy, and chemotherapy-induced painful neuropathy. These effects were shown to be produced by a local action, lasted up to 6 hours after acute treatment, and did not produce tolerance over 15 days of chronic daily dosing. The present results support the hypothesis that allodynia in animal models of CRPS-I and neuropathic pain is effectively relieved by topical combinations of α(2)A or NO donors with PDE or PA inhibitors. This suggests that topical treatments aimed at improving microvascular function may reduce allodynia in patients with CRPS-I and neuropathic pain. This article presents the synergistic antiallodynic effects of combinations of α(2)A or NO donors with PDE or PA inhibitors in animal models of CRPS-I and neuropathic pain. The data suggest that effective clinical treatment of chronic neuropathic pain may be achieved by therapies that alleviate microvascular dysfunction in affected

  15. Deconstructing the sensation of pain: The influence of cognitive processes on pain perception.

    Science.gov (United States)

    Wiech, Katja

    2016-11-04

    Phenomena such as placebo analgesia or pain relief through distraction highlight the powerful influence cognitive processes and learning mechanisms have on the way we perceive pain. Although contemporary models of pain acknowledge that pain is not a direct readout of nociceptive input, the neuronal processes underlying cognitive modulation are not yet fully understood. Modern concepts of perception-which include computational modeling to quantify the influence of cognitive processes-suggest that perception is critically determined by expectations and their modification through learning. Research on pain has just begun to embrace this view. Insights into these processes promise to open up new avenues to pain prevention and treatment by harnessing the power of the mind. Copyright © 2016, American Association for the Advancement of Science.

  16. Tramadol reduces anxiety-related and depression-associated behaviors presumably induced by pain in the chronic constriction injury model of neuropathic pain in rats.

    Science.gov (United States)

    Caspani, Ombretta; Reitz, Marie-Céline; Ceci, Angelo; Kremer, Andreas; Treede, Rolf-Detlef

    2014-09-01

    Depression and anxiety are common comorbidities of neuropathic pain (NP). Pharmacological preclinical studies on NP have given abundant information on the effects of drugs on reflex measures of stimulus-evoked pain. However, few preclinical studies focus on relief of comorbidities evoked by NP. In this study, we investigated the effects of tramadol on nociceptive reflex, depression-associated and anxiety-related behaviors in a NP model in rats. We used chronic constriction injury (CCI) of the sciatic nerve as an animal model of neuropathic pain. We performed electronic von Frey tests (evF) to measure mechanical sensitivity, elevated plus maze tests (EPM) to record anxiety-related behaviors and forced swimming tests (FST) to evaluate depression-associated behaviors. In the evF, CCI rats showed a decrease of 82% of the paw withdrawal threshold (PWT) compared to sham (Ppain and its indirect consequences and comorbidities, and that this study also is a model for pharmacological studies seeking to investigate the effect of drugs on the major disabling symptoms of NP. Copyright © 2014 Elsevier Inc. All rights reserved.

  17. The Effect of Positive Affect on the Memory of Pain.

    Science.gov (United States)

    Bąbel, Przemysław

    2017-06-01

    The aim of the study was to assess the accuracy of the memory of experimentally induced pain and the affect that accompanies experimentally induced pain. Sixty-two healthy female volunteers participated in the study. In the first phase of the study, the participants received three pain stimuli and rated pain intensity, pain unpleasantness, state anxiety, and their positive and negative affect. About a month later, in the second phase of the study, the participants were asked to rate the pain intensity, pain unpleasantness, state anxiety, and the emotions they had felt during the first phase of the study. Both recalled pain intensity and recalled pain unpleasantness were found to be underestimated. Although the positive affect that accompanied pain was remembered accurately, recalled negative affect was overestimated and recalled state anxiety was underestimated. Experienced pain, recalled state anxiety, and recalled positive affect accounted for 44% of the total variance in predicting recalled pain intensity and 61% of the total variance in predicting recalled pain unpleasantness. Together with recent research findings on the memory of other types of pain, the present study supports the idea that pain is accompanied by positive as well as negative emotions, and that positive affect influences the memory of pain. Copyright © 2017 American Society for Pain Management Nursing. Published by Elsevier Inc. All rights reserved.

  18. Lumbopelvic Core Stabilization Exercise and Pain Modulation Among Individuals with Chronic Nonspecific Low Back Pain.

    Science.gov (United States)

    Paungmali, Aatit; Joseph, Leonard H; Sitilertpisan, Patraporn; Pirunsan, Ubon; Uthaikhup, Sureeporn

    2017-11-01

    Lumbopelvic stabilization training (LPST) may provide therapeutic benefits on pain modulation in chronic nonspecific low back pain conditions. This study aimed to examine the effects of LPST on pain threshold and pain intensity in comparison with the passive automated cycling intervention and control intervention among patients with chronic nonspecific low back pain. A within-subject, repeated-measures, crossover randomized controlled design was conducted among 25 participants (7 males and 18 females) with chronic nonspecific low back pain. All the participants received 3 different types of experimental interventions, which included LPST, the passive automated cycling intervention, and the control intervention randomly, with 48 hours between the sessions. The pressure pain threshold (PPT), hot-cold pain threshold, and pain intensity were estimated before and after the interventions. Repeated-measures analysis of variance showed that LPST provided therapeutic effects as it improved the PPT beyond the placebo and control interventions (P pain intensity under the LPST condition was significantly better than that under the passive automated cycling intervention and controlled intervention (P pain threshold under the LPST condition also showed a significant trend of improvement beyond the control (P pain threshold were evident. Lumbopelvic stabilization training may provide therapeutic effects by inducing pain modulation through an improvement in the pain threshold and reduction in pain intensity. LPST may be considered as part of the management programs for treatment of chronic low back pain. © 2017 World Institute of Pain.

  19. Analgesic effects of lappaconitine in leukemia bone pain in a mouse model

    Directory of Open Access Journals (Sweden)

    Xiao-Cui Zhu

    2015-05-01

    Full Text Available Bone pain is a common and severe symptom in cancer patients. The present study employed a mouse model of leukemia bone pain by injection K562 cells into tibia of mouse to evaluate the analgesic effects of lappacontine. Our results showed that the lappaconitine treatment at day 15, 17 and 19 could effectively reduce the spontaneous pain scoring values, restore reduced degree in the inclined-plate test induced by injection of K562 cells, as well as restore paw mechanical withdrawal threshold and paw withdrawal thermal latency induced by injection of K562 cells to the normal levels. Additionally, the molecular mechanisms of lappaconitine’s analgesic effects may be related to affect the expression levels of endogenous opioid system genes (POMC, PENK and MOR, as well as apoptosis-related genes (Xiap, Smac, Bim, NF-κB and p53. Our present results indicated that lappaconitine may become a new analgesic agent for leukemia bone pain management.

  20. Hyperalgesia in a human model of acute inflammatory pain: a methodological study

    DEFF Research Database (Denmark)

    Pedersen, J L; Kehlet, H

    1998-01-01

    as significant for all variables with fewer than 12 subjects in a cross-over design (2alpha = 5% and power = 80%). Between-day comparisons demanded up to 25 subjects to detect changes of the same magnitude. The burns caused mild to moderate pain (VAS: mean 29, SD 14) and the subjects (all right-handed) were more......The aim of the study was to examine reproducibility of primary and secondary hyperalgesia in a psychophysical model of human inflammatory pain. Mild burns were produced on the crura of 12 volunteers with a 50 x 25 mm thermode (47 degrees C, 7 min). Assessments of (i) cold and warm detection...... thresholds, (ii) mechanical and heat pain thresholds, (iii) pain to heat (43 degrees C and 45 degrees C, 5 s), (iv) secondary hyperalgesia, and (v) skin erythema were made 1.75 and 0.5 h before, and 0, 1, 2, 4, and 6 h after a burn injury. Sensory thresholds and hyperalgesia to heat and mechanical stimuli...

  1. Complex Regional Pain Syndrome (CRPS/RSD and Neuropathic Pain: Role of Intravenous Bisphosphonates as Analgesics

    Directory of Open Access Journals (Sweden)

    Jennifer Yanow

    2008-01-01

    Full Text Available Neuropathic pain is a sequela of dysfunction, injuries, or diseases of the peripheral and/or central nervous system pain pathways, which has historically been extremely difficult to treat. Complex regional pain syndrome (CRPS types 1 and 2 are neuropathic pain conditions that have a long history in the medical literature but whose pathophysiology remains elusive and whose available treatment options remain few. While an exact animal model for CRPS doesn't yet exist, there are several animal models of neuropathic pain that develop behaviors of hypersensitivity, one of the hallmark signs of neuropathic pain in humans.

  2. Shared Genetics of Temporomandibular Disorder Pain and Neck Pain: Results of a Twin Study.

    Science.gov (United States)

    Visscher, Corine M; Schouten, Maarten J; Ligthart, Lannie; van Houtem, Caroline Mhh; de Jongh, Ad; Boomsma, Dorret I

    2018-03-06

    (1) To examine the heritability of TMD pain and of neck pain; and (2) to estimate the potential overlap in genetic and environmental factors influencing TMD pain and neck pain. Data from 2,238 adult female twins who completed a survey on TMD pain and neck pain were analyzed. The total variance of TMD pain and neck pain was decomposed into variance attributable to additive genetic effects and nonshared environmental effects. Bivariate structural equation modeling was applied to estimate trait-specific and genetic effects shared between traits. The prevalence of TMD pain and neck pain was 8.6% and 46.8%, respectively, while 6.7% of the twins reported both TMD pain and neck pain. The phenotypic correlation between TMD pain and neck pain, based on a liability threshold model, was 0.43 (95% confidence interval [CI] 0.34 to 0.51). The heritability for TMD was 0.35 (0.17 to 0.51), and for neck pain was 0.33 (0.23 to 0.43). The genetic correlation between TMD pain and neck pain was 0.64 (0.35 to 1.00), and the environmental correlation was 0.32 (0.14 to 0.48). This study shows that variation in TMD pain and neck pain can in part be attributed to genes. The comorbidity between them is partly explained by genes that influence both traits and partly by the same environmental factors.

  3. Development Of A Multivariate Prognostic Model For Pain And Activity Limitation In People With Low Back Disorders Receiving Physiotherapy.

    Science.gov (United States)

    Ford, Jon J; Richards BPhysio, Matt C; Surkitt BPhysio, Luke D; Chan BPhysio, Alexander Yp; Slater, Sarah L; Taylor, Nicholas F; Hahne, Andrew J

    2018-05-28

    To identify predictors for back pain, leg pain and activity limitation in patients with early persistent low back disorders. Prospective inception cohort study; Setting: primary care private physiotherapy clinics in Melbourne, Australia. 300 adults aged 18-65 years with low back and/or referred leg pain of ≥6-weeks and ≤6-months duration. Not applicable. Numerical rating scales for back pain and leg pain as well as the Oswestry Disability Scale. Prognostic factors included sociodemographics, treatment related factors, subjective/physical examination, subgrouping factors and standardized questionnaires. Univariate analysis followed by generalized estimating equations were used to develop a multivariate prognostic model for back pain, leg pain and activity limitation. Fifty-eight prognostic factors progressed to the multivariate stage where 15 showed significant (pduration, high multifidus tone, clinically determined inflammation, higher back and leg pain severity, lower lifting capacity, lower work capacity and higher pain drawing percentage coverage). The preliminary model identifying predictors of low back disorders explained up to 37% of the variance in outcome. This study evaluated a comprehensive range of prognostic factors reflective of both the biomedical and psychosocial domains of low back disorders. The preliminary multivariate model requires further validation before being considered for clinical use. Copyright © 2018. Published by Elsevier Inc.

  4. Phonetic characteristics of vocalizations during pain

    DEFF Research Database (Denmark)

    Niebuhr, Oliver; Lautenbacher, Stefan; Salinas-Ranneberg, Melissa

    2017-01-01

    ” (central vowel, sounding like a darker “e” as in hesitations like “ehm”)—as experimental approximations to natural vocalizations. Methods: In 50 students vowel production and self-report ratings were assessed during painful and nonpainful heat stimulation (hot water immersion) as well as during baseline......Introduction and Objectives: There have, yet, been only few attempts to phonetically characterize the vocalizations of pain, although there is wide agreement that moaning, groaning, or other nonverbal utterance can be indicative of pain. We studied the production of vowels “u,” “a,” “i”, and “schwa...... pain. Furthermore, changes from nonpainful to painful stimulations in these parameters also significantly predicted concurrent changes in pain ratings. Conclusion: Vocalization characteristics of pain seem to be best described by an increase in pitch and in loudness. Future studies using more specific...

  5. A Preliminary Genome-Wide Association Study of Pain-Related Fear: Implications for Orofacial Pain.

    Science.gov (United States)

    Randall, Cameron L; Wright, Casey D; Chernus, Jonathan M; McNeil, Daniel W; Feingold, Eleanor; Crout, Richard J; Neiswanger, Katherine; Weyant, Robert J; Shaffer, John R; Marazita, Mary L

    2017-01-01

    Acute and chronic orofacial pain can significantly impact overall health and functioning. Associations between fear of pain and the experience of orofacial pain are well-documented, and environmental, behavioral, and cognitive components of fear of pain have been elucidated. Little is known, however, regarding the specific genes contributing to fear of pain. A genome-wide association study (GWAS; N = 990) was performed to identify plausible genes that may predispose individuals to various levels of fear of pain. The total score and three subscales (fear of minor, severe, and medical/dental pain) of the Fear of Pain Questionnaire-9 (FPQ-9) were modeled in a variance components modeling framework to test for genetic association with 8.5 M genetic variants across the genome, while adjusting for sex, age, education, and income. Three genetic loci were significantly associated with fear of minor pain (8q24.13, 8p21.2, and 6q26; p pain total score and each of the FPQ-9 subscales. Multiple genes were identified as possible candidates contributing to fear of pain. The findings may have implications for understanding and treating chronic orofacial pain.

  6. DEET potentiates the development and persistence of anticholinesterase dependent chronic pain signs in a rat model of Gulf War Illness pain

    Energy Technology Data Exchange (ETDEWEB)

    Flunker, L.K., E-mail: lflunker@dental.ufl.edu [Division of Neuroscience, Dept. of Oral and Maxillofacial Surgery, Box 100416, JHMHC, University of Florida College of Dentistry, Gainesville, FL 32610 (United States); Nutter, T.J., E-mail: tnutter@dental.ufl.edu [Division of Neuroscience, Dept. of Oral and Maxillofacial Surgery, Box 100416, JHMHC, University of Florida College of Dentistry, Gainesville, FL 32610 (United States); Johnson, R.D., E-mail: rdjohnso@ufl.edu [Dept. of Physiological Sciences, University of Florida College of Veterinary Science, Gainesville, FL 32610 (United States); Cooper, B.Y., E-mail: bcooper@dental.ufl.edu [Division of Neuroscience, Dept. of Oral and Maxillofacial Surgery, Box 100416, JHMHC, University of Florida College of Dentistry, Gainesville, FL 32610 (United States)

    2017-02-01

    Exposure to DEET (N,N-diethyl-meta-toluamide) may have influenced the pattern of symptoms observed in soldiers with GWI (Gulf War Illness; Haley and Kurt, 1997). We examined how the addition of DEET (400 mg/kg; 50% topical) to an exposure protocol of permethrin (2.6 mg/kg; topical), chlorpyrifos (CP; 120 mg/kg), and pyridostigmine bromide (PB;13 mg/kg) altered the emergence and pattern of pain signs in an animal model of GWI pain (). Rats underwent behavioral testing before, during and after a 4 week exposure: 1) hindlimb pressure withdrawal threshold; 2) ambulation (movement distance and rate); and 3) resting duration. Additional studies were conducted to assess the influence of acute DEET (10–100 μM) on muscle and vascular nociceptor K{sub v}7, K{sub DR}, Na{sub v}1.8 and Na{sub v}1.9. We report that a 50% concentration of DEET enhanced the development and persistence of pain-signs. Rats exposed to all 4 compounds exhibited ambulation deficits that appeared 5–12 weeks post-exposure and persisted through weeks 21–24. Rats exposed to only three agents (CP or PB excluded), did not fully develop ambulation deficits. When PB was excluded, rats also developed rest duration pain signs, in addition to ambulation deficits. There was no evidence that physiological doses of DEET acutely modified nociceptor K{sub v}7, K{sub DR}, Na{sub v}1.8 or Na{sub v}1.9 activities. Nevertheless, DEET augmented protocols decreased the conductance of K{sub v}7 expressed in vascular nociceptors harvested from chronically exposed rats. We concluded that DEET enhanced the development and persistence of pain behaviors, but the anticholinesterases CP and PB played a determinant role. - Highlights: • DEET accelerated and prolonged pain-like behaviors in a rat model of Gulf War Illness. • The development of pain behaviors were dependent upon chlorpyrifos and pyridostigmine. • Conductance of vascular nociceptor Kv7 was diminished 12 weeks following exposures. • DEET did not have any

  7. Systemic synergism between codeine and morphine in three pain models in mice.

    Science.gov (United States)

    Miranda, Hugo F; Noriega, Viviana; Zepeda, Ramiro J; Sierralta, Fernando; Prieto, Juan C

    2013-01-01

    The combination of two analgesic agents offers advantages in pain treatment. Codeine and morphine analgesia is due to activation of opioid receptor subtypes. This study, performed in mice using isobolographic analysis, evaluated the type of interaction in intraperitoneal (ip) or intrathecal (it) coadministration of codeine and morphine, in three nociceptive behavioral models. Intrathecal morphine resulted to be 7.5 times more potent than ip morphine in the writhing test, 55.6 times in the tail flick test and 1.7 times in phase II of the orofacial formalin test; however, in phase I of the same test ip was 1.2 times more potent than it morphine. Intrathecal codeine resulted being 3.4 times more potent than ip codeine in the writhing test, 1.6 times in the tail flick test, 2.5 times in phase I and 6.7 times in phase II of the orofacial formalin test. Opioid coadministration had a synergistic effect in the acute tonic pain (acetic acid writhing test), acute phasic pain (tail flick test) and inflammatory pain (orofacial formalin test). The interaction index ranged between 0.284 (writhing ip) and 0.440 (orofacial formalin phase II ip). This synergy may relate to the different pathways of pain transmission and to the different intracellular signal transduction. The present findings also raise the possibility of potential clinical advantages in combining opioids in pain management.

  8. [Nursing intervention and evaluation of postoperative pain in preschool children with cleft lip and palate].

    Science.gov (United States)

    Gong, Caixia; Yan, Miao; Jiang, Fei; Chen, Zehua; Long, Yuan; Chen, Lixian; Zheng, Qian; Shi, Bing

    2014-06-01

    This study aimed to observe the postoperative pain rate and degree of pain in preschool children with cleft lip and palate, and investigate the effect of nursing intervention on pain relief. A total of 120 hospitalized cases of three- to seven-year-old preschool children with cleft lip and palate were selected from May to October 2011. The subjects were randomly divided into the control group and experimental groups 1, 2, and 3. The control group used conventional nursing methods, experimental group 1 used analgesic drug treatment, experimental group 2 used psychological nursing interventions, and experimental group 3 used both psychological nursing intervention and analgesic drug treatment. After 6, 12, 24, and 48 h, pain self-assessment, pain parent-assessment, and pain nurse-assessment were calculated for the four groups using the pain assessment forms, and their ratings were compared. The postoperative pain rates of the four groups ranged from 50.0% to 73.3%. The difference among the four groups was statistically significant (P palate is common. Psychological nursing intervention with analgesic treatment is effective in relieving postoperative pain.

  9. IMMEDIATE EFFECT OF CERVICAL MANIPULATION ON PAIN AND RANGE OF MOTION IN PATIENTS WITH CHRONIC MECHANICAL NECK PAIN

    Directory of Open Access Journals (Sweden)

    Kabir Isah Mayana

    2017-06-01

    Full Text Available Background: Neck pain has been reported as a prevalent musculoskeletal disorder globally with more than half of the general population being affected once or more within their life span. Methods: A randomized clinical trial research design was used which investigated the immediate effect of cervical manipulation on neck pain and cervical range of motion among patients with chronic mechanical neck pain. 20 male and female participants between the ages of 26 to 60 years with chronic mechanical neck pain attending physiotherapy clinics were recruited. They were randomly assigned into two groups (A and B of 10 patients each. Group A received soft tissue massage, and cervical manipulation and group B served as the control group, and they received only soft tissue massage. There were two outcomes measured; Pain intensity was rated using visual analog scale (VAS before and immediately after the intervention. Pre and Post intervention measurements of cervical spine range of motion using Goniometer were also taken. Results: Findings of the study revealed significant immediate improvement of pain and Cervical Range of Motions (p<0.05 in all dimensions in the experimental group while Pain, flexion and right side Cervical flexion significantly improved in the control group. It was also found out after comparing the outcomes between the two groups that, the experimental group had significantly (p<0.05 better improvement than the control group in post-intervention pain, cervical flexion, cervical extension and cervical (right and left lateral rotations. Conclusion: Cervical manipulation is effective in immediate pain relief and improvement in cervical range of motion in patients with mechanical neck pain

  10. The effectiveness of virtual reality distraction for pain reduction: a systematic review.

    Science.gov (United States)

    Malloy, Kevin M; Milling, Leonard S

    2010-12-01

    Virtual reality technology enables people to become immersed in a computer-simulated, three-dimensional environment. This article provides a comprehensive review of controlled research on the effectiveness of virtual reality (VR) distraction for reducing pain. To be included in the review, studies were required to use a between-subjects or mixed model design in which VR distraction was compared with a control condition or an alternative intervention in relieving pain. An exhaustive search identified 11 studies satisfying these criteria. VR distraction was shown to be effective for reducing experimental pain, as well as the discomfort associated with burn injury care. Studies of needle-related pain provided less consistent findings. Use of more sophisticated virtual reality technology capable of fully immersing the individual in a virtual environment was associated with greater relief. Overall, controlled research suggests that VR distraction may be a useful tool for clinicians who work with a variety of pain problems. Copyright © 2010 Elsevier Ltd. All rights reserved.

  11. Experimental model for evaluation of the cutaneous sensitivity of the abdomen

    Directory of Open Access Journals (Sweden)

    Andreia Bufoni Farah

    2004-12-01

    Full Text Available The purpose of this study is to report an experimental model to evaluate several modalities of sensibility and to map the areas of the abdominal wall with decreased sensibility after abdominoplasty. Patients were divided in two groups: in the control group, patients had no previous abdominal incisions and patients of the experimental group had been undergone abdominoplasty. The sensibility evaluation of patients from the experimental group was made from 12 to 60 months after the operation. The abdominal skin was divided into twelve areas; nine of them were above the abdominoplasty incision and three below it. Sensibility to superficial touch, superficial pain, hot and cold temperature, vibration was tested and recorded as positive if the patient mentioned that he felt the stimulation or negative. Sensibility to pressure was tested with the use of different weights; therefore, a value was obtained when the patient felt the pressure. A specific test was used to evaluate each modality of sensibility. The experimental model designed to test skin sensibility after abdominoplasty showed to be feasible in patients.O objetivo deste estudo é relatar e divulgar um modelo experimental para avaliar diversas modalidades de sensibilidade e mapear as áreas da parede abdominal nas quais ocorre diminuição da sensibilidade após abdominoplastia. Dois grupos de pacientes foram estudados: no grupo controle, as paciente não apresentavam incisões abdominais prévias e as pacientes do grupo experimental tinham sido submetidas a abdominoplastia. A avaliação da sensibilidade das pacientes do grupo experimental foi realizada de 12 a 60 meses após a cirurgia. A pele abdominal foi dividida em doze áreas, sendo nove acima e três abaixo da cicatriz da abdominoplastia. As sensibilidades ao toque superficial, dor superficial, ao calor e frio, vibração foram testadas e registradas como positive se a paciente referisse que sentiu o estímulo ou, caso o contr

  12. Effect of Pain Neuroscience Education Combined With Cognition-Targeted Motor Control Training on Chronic Spinal Pain: A Randomized Clinical Trial.

    Science.gov (United States)

    Malfliet, Anneleen; Kregel, Jeroen; Coppieters, Iris; De Pauw, Robby; Meeus, Mira; Roussel, Nathalie; Cagnie, Barbara; Danneels, Lieven; Nijs, Jo

    2018-04-16

    Effective treatments for chronic spinal pain are essential to reduce the related high personal and socioeconomic costs. To compare pain neuroscience education combined with cognition-targeted motor control training with current best-evidence physiotherapy for reducing pain and improving functionality, gray matter morphologic features, and pain cognitions in individuals with chronic spinal pain. Multicenter randomized clinical trial conducted from January 1, 2014, to January 30, 2017, among 120 patients with chronic nonspecific spinal pain in 2 outpatient hospitals with follow-up at 3, 6, and 12 months. Participants were randomized into an experimental group (combined pain neuroscience education and cognition-targeted motor control training) and a control group (combining education on back and neck pain and general exercise therapy). Primary outcomes were pain (pressure pain thresholds, numeric rating scale, and central sensitization inventory) and function (pain disability index and mental health and physical health). There were 22 men and 38 women in the experimental group (mean [SD] age, 39.9 [12.0] years) and 25 men and 35 women in the control group (mean [SD] age, 40.5 [12.9] years). Participants in the experimental group experienced reduced pain (small to medium effect sizes): higher pressure pain thresholds at primary test site at 3 months (estimated marginal [EM] mean, 0.971; 95% CI, -0.028 to 1.970) and reduced central sensitization inventory scores at 6 months (EM mean, -5.684; 95% CI, -10.589 to -0.780) and 12 months (EM mean, -6.053; 95% CI, -10.781 to -1.324). They also experienced improved function (small to medium effect sizes): significant and clinically relevant reduction of disability at 3 months (EM mean, -5.113; 95% CI, -9.994 to -0.232), 6 months (EM mean, -6.351; 95% CI, -11.153 to -1.550), and 12 months (EM mean, -5.779; 95% CI, -10.340 to -1.217); better mental health at 6 months (EM mean, 36.496; 95% CI, 7.998-64.995); and better physical

  13. Effects of a pain program on nurses' pharmacological pain management

    NARCIS (Netherlands)

    Francke, AL; Dingemans, WA; Borg, PAJ; Luiken, JB; Grypdonck, M; Abu-Saad, HH

    1999-01-01

    Surgical nurses from five Dutch general hospitals participated in a continuing education program on pain assessment and management. Effects of the program were measured in a pretest-post-test control group design, in which nursing wards were randomly allocated to the experimental condition (program)

  14. Calcitonin gene-related peptide and pain

    DEFF Research Database (Denmark)

    Schou, Wendy Sophie; Ashina, Sait; Amin, Faisal Mohammad

    2017-01-01

    and cerebrospinal fluid in subjects with musculoskeletal pain. A randomized clinical trial on monoclonal antibody, which selectively binds to and inhibits the activity of CGRP (galcanezumab) in patients with osteoarthritis knee pain, failed to demonstrate improvement of pain compared with placebo. No studies......BACKGROUND: Calcitonin gene-related peptide (CGRP) is widely distributed in nociceptive pathways in human peripheral and central nervous system and its receptors are also expressed in pain pathways. CGRP is involved in migraine pathophysiology but its role in non-headache pain has not been...... clarified. METHODS: We performed a systematic literature search on PubMed, Embase and ClinicalTrials.gov for articles on CGRP and non-headache pain covering human studies including experimental studies and randomized clinical trials. RESULTS: The literature search identified 375 citations of which 50...

  15. Sub-paresthesia spinal cord stimulation reverses thermal hyperalgesia and modulates low frequency EEG in a rat model of neuropathic pain.

    Science.gov (United States)

    Koyama, Suguru; Xia, Jimmy; Leblanc, Brian W; Gu, Jianwen Wendy; Saab, Carl Y

    2018-05-08

    Paresthesia, a common feature of epidural spinal cord stimulation (SCS) for pain management, presents a challenge to the double-blind study design. Although sub-paresthesia SCS has been shown to be effective in alleviating pain, empirical criteria for sub-paresthesia SCS have not been established and its basic mechanisms of action at supraspinal levels are unknown. We tested our hypothesis that sub-paresthesia SCS attenuates behavioral signs of neuropathic pain in a rat model, and modulates pain-related theta (4-8 Hz) power of the electroencephalogram (EEG), a previously validated correlate of spontaneous pain in rodent models. Results show that sub-paresthesia SCS attenuates thermal hyperalgesia and power amplitude in the 3-4 Hz range, consistent with clinical data showing significant yet modest analgesic effects of sub-paresthesia SCS in humans. Therefore, we present evidence for anti-nociceptive effects of sub-paresthesia SCS in a rat model of neuropathic pain and further validate EEG theta power as a reliable 'biosignature' of spontaneous pain.

  16. Bisphosphonates Inhibit Pain, Bone Loss, and Inflammation in a Rat Tibia Fracture Model of Complex Regional Pain Syndrome.

    Science.gov (United States)

    Wang, Liping; Guo, Tian-Zhi; Hou, Saiyun; Wei, Tzuping; Li, Wen-Wu; Shi, Xiaoyou; Clark, J David; Kingery, Wade S

    2016-10-01

    Bisphosphonates are used to prevent the bone loss and fractures associated with osteoporosis, bone metastases, multiple myeloma, and osteogenesis deformans. Distal limb fractures cause regional bone loss with cutaneous inflammation and pain in the injured limb that can develop into complex regional pain syndrome (CRPS). Clinical trials have reported that antiresorptive bisphosphonates can prevent fracture-induced bone loss, inhibit serum inflammatory cytokine levels, and alleviate CRPS pain. Previously, we observed that the inhibition of inflammatory cytokines or adaptive immune responses attenuated the development of pain behavior in a rat fracture model of CRPS, and we hypothesized that bisphosphonates could prevent pain behavior, trabecular bone loss, postfracture cutaneous cytokine upregulation, and adaptive immune responses in this CRPS model. Rats underwent tibia fracture and cast immobilization for 4 weeks and were chronically administered either subcutaneously perfused alendronate or oral zoledronate. Behavioral measurements included hindpaw von Frey allodynia, unweighting, warmth, and edema. Bone microarchitecture was measured by microcomputed tomography, and bone cellular activity was evaluated by static and dynamic histomorphometry. Spinal cord Fos immunostaining was performed, and skin cytokine (tumor necrosis factor, interleukin [IL]-1, IL-6) and nerve growth factor (NGF) levels were determined by enzyme immunoassay. Skin and sciatic nerve immunoglobulin levels were determined by enzyme immunoassay. Rats with tibia fractures developed hindpaw allodynia, unweighting, warmth, and edema, increased spinal Fos expression and trabecular bone loss in the lumbar vertebra and bilateral distal femurs as measured by microcomputed tomography, increased trabecular bone resorption and osteoclast surface with decreased bone formation rates, increased cutaneous inflammatory cytokine and NGF expression, and elevated immunocomplex deposition in skin and nerve

  17. Injury Based on Its Study in Experimental Models

    Directory of Open Access Journals (Sweden)

    M. Mendes-Braz

    2012-01-01

    Full Text Available The present review focuses on the numerous experimental models used to study the complexity of hepatic ischemia/reperfusion (I/R injury. Although experimental models of hepatic I/R injury represent a compromise between the clinical reality and experimental simplification, the clinical transfer of experimental results is problematic because of anatomical and physiological differences and the inevitable simplification of experimental work. In this review, the strengths and limitations of the various models of hepatic I/R are discussed. Several strategies to protect the liver from I/R injury have been developed in animal models and, some of these, might find their way into clinical practice. We also attempt to highlight the fact that the mechanisms responsible for hepatic I/R injury depend on the experimental model used, and therefore the therapeutic strategies also differ according to the model used. Thus, the choice of model must therefore be adapted to the clinical question being answered.

  18. Study on Bee venom and Pain

    Directory of Open Access Journals (Sweden)

    Hyoung-Seok Yun

    2000-07-01

    Full Text Available In order to study Bee venom and Pain, We searched Journals and Internet. The results were as follows: 1. The domestic papers were total 13. 4 papers were published at The journal of korean acupuncture & moxibustion society, 3 papers were published at The journal of korean oriental medical society, Each The journal of KyoungHee University Oriental Medicine and The journal of korean sports oriental medical society published 1 papers and Unpublished desertations were 3. The clinical studies were 4 and the experimental studies were 9. 2. The domestic clinical studies reported that Bee venom Herbal Acupuncture therapy was effective on HIVD, Subacute arthritis of Knee Joint and Sequale of sprain. In the domestic experimental studies, 5 were related to analgesic effect of Bee vnom and 4 were related to mechanism of analgesia. 3. The journals searched by PubMed were total 18. 5 papers were published at Pain, Each 2 papers were published at Neurosci Lett. and Br J Pharmacol, and Each Eur J Pain, J Rheumatol, Brain Res, Neuroscience, Nature and Toxicon et al published 1 paper. 4. In the journals searched by PubMed, Only the experimental studies were existed. 8 papers used Bee Venom as pain induction substance and 1 paper was related to analgesic effects of Bee venom. 5. 15 webpage were searched by internet related to Bee Venom and pain. 11 were the introduction related to arthritis, 1 was the advertisement, 1 was the patient's experience, 1 was the case report on RA, 1 was review article.

  19. A review of heat transfer in human tooth--experimental characterization and mathematical modeling.

    Science.gov (United States)

    Lin, Min; Xu, Feng; Lu, Tian Jian; Bai, Bo Feng

    2010-06-01

    With rapid advances in modern dentistry, high-energy output instruments (e.g., dental lasers and light polymerizing units) are increasingly employed in dental surgery for applications such as laser assisted tooth ablation, bleaching, hypersensitivity treatment and polymerization of dental restorative materials. Extreme high temperature occurs within the tooth during these treatments, which may induce tooth thermal pain (TTP) sensation. Despite the wide application of these dental treatments, the underlying mechanisms are far from clear. Therefore, there is an urgent need to better understand heat transfer (HT) process in tooth, thermally induced damage of tooth, and the corresponding TTP. This will enhance the design and optimization of clinical treatment strategies. This paper presents the state-of-the-art of the current understanding on HT in tooth, with both experimental study and mathematical modeling reviewed. Limitations of the current experimental and mathematical methodologies are discussed and potential solutions are suggested. Interpretation of TTP in terms of thermally stimulated dentinal fluid flow is also discussed. Copyright (c) 2010 Academy of Dental Materials. All rights reserved.

  20. Intradiscal electrothermal treatment for discogenic back pain: experimental investigation and preliminary clinical application

    International Nuclear Information System (INIS)

    Fang Wen; Teng Gaojun; He Shicheng; Guo Jinhe; Deng Gang; Zhu Guangyu; Li Guozhao; Ding Huijuan; Shen Zhiping

    2005-01-01

    Objective: To assess the effectiveness and the safety of IDET for chronic discogenic low back pain. Methods: Standard intradiscal electrothermal treatment were performed in two adjacent disc levels (L3-4, L4-5) of two domestic pigs. MRI were available at pretreatment, posttreatment of 1,2 weeks, and then the two animals were killed respectively at 1,2 weeks after the procedure. The specimens were then undergone thin sectioned and subjected to humatoxylin and eosin staining for histological investigation. 23 patients (totally 29 discs, including L2-3 to L5-S1) with chronic symptoms underwent IDET for clinical study. VAS (Visual Analog Scale) pain scores were collected before the treatment, 1 week and 3 months after the procedure. One way ANOVA was used for statistical analysis. Results: 4 discs of standard IDET models have been set up in two pigs showing normal MRI T2W1 signal of nucleus pulposus immediately after the procedure, but the high signal extent of the central part of the nucleo pulposus shrinked with conspicuous peripheral low signal changes during the following 1-2 W. Degeneration and shrinkage of nucleo-pulposus with lecolized fibrous ring thickening were found pathologically but without damage to nurve roots and epidural sac. 29 discs in 23 patients were performed successfully, without complication. The follow-up evaluation of 1 week and 3 months after the treatment showing significant differences with those before the treatment on was scores 65.3% and 78.9% respectively (P<0.0001). Conclusions: IDET is safe and effective for chronic discogenic low back pain. (authors)

  1. Modeling of Experimental Adsorption Isotherm Data

    Directory of Open Access Journals (Sweden)

    Xunjun Chen

    2015-01-01

    Full Text Available Adsorption is considered to be one of the most effective technologies widely used in global environmental protection areas. Modeling of experimental adsorption isotherm data is an essential way for predicting the mechanisms of adsorption, which will lead to an improvement in the area of adsorption science. In this paper, we employed three isotherm models, namely: Langmuir, Freundlich, and Dubinin-Radushkevich to correlate four sets of experimental adsorption isotherm data, which were obtained by batch tests in lab. The linearized and non-linearized isotherm models were compared and discussed. In order to determine the best fit isotherm model, the correlation coefficient (r2 and standard errors (S.E. for each parameter were used to evaluate the data. The modeling results showed that non-linear Langmuir model could fit the data better than others, with relatively higher r2 values and smaller S.E. The linear Langmuir model had the highest value of r2, however, the maximum adsorption capacities estimated from linear Langmuir model were deviated from the experimental data.

  2. Development and Psychometric Evaluation of a New Measure of Pain-Related Support Preferences: The Pain Response Preference Questionnaire

    Directory of Open Access Journals (Sweden)

    Lachlan A McWilliams

    2009-01-01

    Full Text Available BACKGROUND: Behavioural conceptualizations of chronic pain posit that solicitous responses to pain behaviours are positively reinforcing and play a role in the development of chronic pain and disability. Recent research suggests that studies investigating this model were likely limited by the use of only a few narrowly defined categories of responses to pain behaviour. A measure of preferences regarding pain-related social support has the potential to improve behavioural models of chronic pain by identifying other potentially reinforcing responses to pain behaviour.

  3. Mechanisms of Stress-Induced Visceral Pain: Implications in Irritable Bowel Syndrome.

    Science.gov (United States)

    Greenwood-Van Meerveld, B; Moloney, R D; Johnson, A C; Vicario, M

    2016-08-01

    Visceral pain is a term describing pain originating from the internal organs of the body and is a common feature of many disorders, including irritable bowel syndrome (IBS). Stress is implicated in the development and exacerbation of many visceral pain disorders. Recent evidence suggests that stress and the gut microbiota can interact through complementary or opposing factors to influence visceral nociceptive behaviours. The Young Investigator Forum at the International Society of Psychoneuroendocrinology (ISPNE) annual meeting reported experimental evidence suggesting the gut microbiota can affect the stress response to affect visceral pain. Building upon human imaging data showing abnormalities in the central processing of visceral stimuli in patients with IBS and knowledge that the amygdala plays a pivotal role in facilitating the stress axis, the latest experimental evidence supporting amygdala-mediated mechanisms in stress-induced visceral pain was reviewed. The final part of the session at ISPNE reviewed experimental evidence suggesting that visceral pain in IBS may be a result, at least in part, of afferent nerve sensitisation following increases in epithelial permeability and mucosal immune activation. © 2016 British Society for Neuroendocrinology.

  4. Lack of predictive power of trait fear and anxiety for conditioned pain modulation (CPM).

    Science.gov (United States)

    Horn-Hofmann, Claudia; Priebe, Janosch A; Schaller, Jörg; Görlitz, Rüdiger; Lautenbacher, Stefan

    2016-12-01

    In recent years the association of conditioned pain modulation (CPM) with trait fear and anxiety has become a hot topic in pain research due to the assumption that such variables may explain the low CPM efficiency in some individuals. However, empirical evidence concerning this association is still equivocal. Our study is the first to investigate the predictive power of fear and anxiety for CPM by using a well-established psycho-physiological measure of trait fear, i.e. startle potentiation, in addition to two self-report measures of pain-related trait anxiety. Forty healthy, pain-free participants (female: N = 20; age: M = 23.62 years) underwent two experimental blocks in counter-balanced order: (1) a startle paradigm with affective picture presentation and (2) a CPM procedure with hot water as conditioning stimulus (CS) and contact heat as test stimulus (TS). At the end of the experimental session, pain catastrophizing (PCS) and pain anxiety (PASS) were assessed. PCS score, PASS score and startle potentiation to threatening pictures were entered as predictors in a linear regression model with CPM magnitude as criterion. We were able to show an inhibitory CPM effect in our sample: pain ratings of the heat stimuli were significantly reduced during hot water immersion. However, CPM was neither predicted by self-report of pain-related anxiety nor by startle potentiation as psycho-physiological measure of trait fear. These results corroborate previous negative findings concerning the association between trait fear/anxiety and CPM efficiency and suggest that shifting the focus from trait to state measures might be promising.

  5. Fluid mechanics in dentinal microtubules provides mechanistic insights into the difference between hot and cold dental pain.

    Science.gov (United States)

    Lin, Min; Luo, Zheng Yuan; Bai, Bo Feng; Xu, Feng; Lu, Tian Jian

    2011-03-23

    Dental thermal pain is a significant health problem in daily life and dentistry. There is a long-standing question regarding the phenomenon that cold stimulation evokes sharper and more shooting pain sensations than hot stimulation. This phenomenon, however, outlives the well-known hydrodynamic theory used to explain dental thermal pain mechanism. Here, we present a mathematical model based on the hypothesis that hot or cold stimulation-induced different directions of dentinal fluid flow and the corresponding odontoblast movements in dentinal microtubules contribute to different dental pain responses. We coupled a computational fluid dynamics model, describing the fluid mechanics in dentinal microtubules, with a modified Hodgkin-Huxley model, describing the discharge behavior of intradental neuron. The simulated results agreed well with existing experimental measurements. We thence demonstrated theoretically that intradental mechano-sensitive nociceptors are not "equally sensitive" to inward (into the pulp) and outward (away from the pulp) fluid flows, providing mechanistic insights into the difference between hot and cold dental pain. The model developed here could enable better diagnosis in endodontics which requires an understanding of pulpal histology, neurology and physiology, as well as their dynamic response to the thermal stimulation used in dental practices.

  6. Novel orally available salvinorin A analog PR-38 inhibits gastrointestinal motility and reduces abdominal pain in mouse models mimicking irritable bowel syndrome.

    Science.gov (United States)

    Sałaga, M; Polepally, P R; Sobczak, M; Grzywacz, D; Kamysz, W; Sibaev, A; Storr, M; Do Rego, J C; Zjawiony, J K; Fichna, J

    2014-07-01

    The opioid and cannabinoid systems play a crucial role in multiple physiological processes in the central nervous system and in the periphery. Selective opioid as well as cannabinoid (CB) receptor agonists exert a potent inhibitory action on gastrointestinal (GI) motility and pain. In this study, we examined (in vitro and in vivo) whether PR-38 (2-O-cinnamoylsalvinorin B), a novel analog of salvinorin A, can interact with both systems and demonstrate therapeutic effects. We used mouse models of hypermotility, diarrhea, and abdominal pain. We also assessed the influence of PR-38 on the central nervous system by measurement of motoric parameters and exploratory behaviors in mice. Subsequently, we investigated the pharmacokinetics of PR-38 in mouse blood samples after intraperitoneal and oral administration. PR-38 significantly inhibited mouse colonic motility in vitro and in vivo. Administration of PR-38 significantly prolonged the whole GI transit time, and this effect was mediated by µ- and κ-opioid receptors and the CB1 receptor. PR-38 reversed hypermotility and reduced pain in mouse models mimicking functional GI disorders. These data expand our understanding of the interactions between opioid and cannabinoid systems and their functions in the GI tract. We also provide a novel framework for the development of future potential treatments of functional GI disorders. Copyright © 2014 by The American Society for Pharmacology and Experimental Therapeutics.

  7. Stage-dependent analgesia of electro-acupuncture in a mouse model of cutaneous cancer pain.

    Science.gov (United States)

    Mao-Ying, Qi-Liang; Cui, Ke-Mi; Liu, Qiong; Dong, Zhi-Qiang; Wang, Wei; Wang, Jun; Sha, Hong; Wu, Gen-Cheng; Wang, Yan-Qing

    2006-11-01

    Acupuncture is one of the most effective alternative medical treatments in pain management with the advantages of simple application, low cost and minimal side effects. However its scientific evidence and laws of action are not very clear in cancer pain relieving. The aim of this study was to examine the immediate and therapeutic anti-hyperalgesic effect of electro-acupuncture (EA) on a mouse model of cutaneous cancer pain. B16-BL6 melanoma cells were inoculated into the plantar region of unilateral hind paw and the thermal hyperalgesia was measured by using radiant heat test and hot plate test. C57BL/6 mice showed moderate and marked hyperalgesia during days 8-12 and from day 14 after the orthotopic inoculation of B16-BL6 melanoma cells into the hind paw. Single EA on day 8 after inoculation showed significant analgesic effect immediately after the treatment, the analgesic effect reached its maximum within 15-30min and declined to its minimum at 50min after EA treatment. Single EA treatment on day 20 showed no significant analgesic effect; Repeated EA treatments (started from day 8, once every other day) showed therapeutic analgesic effect, while it showed no therapeutic effect when started from day 16, a relatively late stage of this cancer pain model. The results demonstrated that EA had anti-hyperalgesic effect on early stage of cutaneous cancer pain but not on late stage. These results indicated a tight correlation of EA anti-hyperalgesic effects with the time window of cancer pain.

  8. Measuring pain phenomena after spinal cord injury: Development and psychometric properties of the SCI-QOL Pain Interference and Pain Behavior assessment tools.

    Science.gov (United States)

    Cohen, Matthew L; Kisala, Pamela A; Dyson-Hudson, Trevor A; Tulsky, David S

    2018-05-01

    To develop modern patient-reported outcome measures that assess pain interference and pain behavior after spinal cord injury (SCI). Grounded-theory based qualitative item development; large-scale item calibration field-testing; confirmatory factor analyses; graded response model item response theory analyses; statistical linking techniques to transform scores to the Patient Reported Outcome Measurement Information System (PROMIS) metric. Five SCI Model Systems centers and one Department of Veterans Affairs medical center in the United States. Adults with traumatic SCI. N/A. Spinal Cord Injury - Quality of Life (SCI-QOL) Pain Interference item bank, SCI-QOL Pain Interference short form, and SCI-QOL Pain Behavior scale. Seven hundred fifty-seven individuals with traumatic SCI completed 58 items addressing various aspects of pain. Items were then separated by whether they assessed pain interference or pain behavior, and poorly functioning items were removed. Confirmatory factor analyses confirmed that each set of items was unidimensional, and item response theory analyses were used to estimate slopes and thresholds for the items. Ultimately, 7 items (4 from PROMIS) comprised the Pain Behavior scale and 25 items (18 from PROMIS) comprised the Pain Interference item bank. Ten of these 25 items were selected to form the Pain Interference short form. The SCI-QOL Pain Interference item bank and the SCI-QOL Pain Behavior scale demonstrated robust psychometric properties. The Pain Interference item bank is available as a computer adaptive test or short form for research and clinical applications, and scores are transformed to the PROMIS metric.

  9. Electroacupuncture Alleviates Pain Responses and Inflammation in a Rat Model of Acute Gout Arthritis

    Directory of Open Access Journals (Sweden)

    Wenxin Chai

    2018-01-01

    Full Text Available Acute gout arthritis is one of the most painful inflammatory conditions. Treatments for gout pain are limited to colchicine, nonsteroidal anti-inflammatory drugs, and corticosteroids, which oftentimes result in severe adverse effects. Electroacupuncture (EA has been proved to be effective in relieving many inflammatory pain conditions with few side effects. Here, we aim to investigate the therapeutic potentials of EA on pain and inflammation of a rat model of acute gout arthritis and underlying mechanisms. We found that 2/100 Hz EA produced the most robust analgesic effect on mechanical hyperalgesia of acute gout arthritis rat model compared with 2 and 100 Hz. EA produced similar analgesic effect compared with indomethacin. 2/100 Hz EA also significantly alleviates the ongoing pain behavior, thermal hyperalgesia, and ankle edema. Locally applied μ and κ-opioid receptor antagonists but not adenosine A1 receptor antagonist significantly abolished the analgesic effect of EA. Locally applied μ and κ-opioid receptor agonists produced significant antiallodynia on acute gout arthritis rats, mimicking EA. Furthermore, 2/100 Hz EA upregulated β-endorphin expression in inflamed ankle skin tissue. Our results demonstrated, for the first time, that EA can be used for relieving acute gout arthritis with effect dependent on peripheral opioid system and comparable with the one obtained with indomethacin.

  10. Orofacial neuropathic pain mouse model induced by Trigeminal Inflammatory Compression (TIC of the infraorbital nerve

    Directory of Open Access Journals (Sweden)

    Ma Fei

    2012-12-01

    Full Text Available Abstract Background Trigeminal neuropathic pain attacks can be excruciating for patients, even after being lightly touched. Although there are rodent trigeminal nerve research models to study orofacial pain, few models have been applied to studies in mice. A mouse trigeminal inflammatory compression (TIC model is introduced here which successfully and reliably promotes vibrissal whisker pad hypersensitivity. Results The chronic orofacial neuropathic pain model is induced after surgical placement of chromic gut suture in the infraorbital nerve fissure in the maxillary bone. Slight compression and chemical effects of the chromic gut suture on the portion of the infraorbital nerve contacted cause mild nerve trauma. Nerve edema is observed in the contacting infraorbital nerve bundle as well as macrophage infiltration in the trigeminal ganglia. Centrally in the spinal trigeminal nucleus, increased immunoreactivity for an activated microglial marker is evident (OX42, postoperative day 70. Mechanical thresholds of the affected whisker pad are significantly decreased on day 3 after chromic gut suture placement, persisting at least 10 weeks. The mechanical allodynia is reversed by suppression of microglial activation. Cold allodynia was detected at 4 weeks. Conclusions A simple, effective, and reproducible chronic mouse model mimicking clinical orofacial neuropathic pain (Type 2 is induced by placing chromic gut suture between the infraorbital nerve and the maxillary bone. The method produces mild inflammatory compression with significant continuous mechanical allodynia persisting at least 10 weeks and cold allodynia measureable at 4 weeks.

  11. Side effects of pain and analgesia in animal experimentation.

    Science.gov (United States)

    Jirkof, Paulin

    2017-03-22

    This review highlights selected effects of untreated pain and of widely used analgesics such as opioids, non-steroid anti-inflammatory drugs and antipyretics, to illustrate the relevance of carefully planned, appropriate and controlled analgesia for greater reproducibility in animal experiments involving laboratory rodents.

  12. Is physiotherapy integrated virtual walking effective on pain, function, and kinesiophobia in patients with non-specific low-back pain? Randomised controlled trial.

    Science.gov (United States)

    Yilmaz Yelvar, Gul Deniz; Çırak, Yasemin; Dalkılınç, Murat; Parlak Demir, Yasemin; Guner, Zeynep; Boydak, Ayşenur

    2017-02-01

    According to literature, virtual reality was found to reduce pain and kinesiophobia in patients with chronic pain. The purpose of the study was to investigate short-term effect of the virtual reality on pain, function, and kinesiophobia in patients with subacute and chronic non-specific low-back pain METHODS: This randomised controlled study in which 44 patients were randomly assigned to the traditional physiotherapy (control group, 22 subjects) or virtual walking integrated physiotherapy (experimental group, 22 subjects). Before and after treatment, Visual Analog Scale (VAS), TAMPA Kinesiophobia Scale (TKS), Oswestry Disability Index (ODI), Nottingham Health Profile (NHP), Timed-up and go Test (TUG), 6-Minute Walk Test (6MWT), and Single-Leg Balance Test were assessed. The interaction effect between group and time was assessed by using repeated-measures analysis of covariance. After treatment, both groups showed improvement in all parameters. However, VAS, TKS, TUG, and 6MWT scores showed significant differences in favor of the experimental group. Virtual walking integrated physiotherapy reduces pain and kinesiophobia, and improved function in patients with subacute and chronic non-specific low-back pain in short term.

  13. Pain Intervention for people with Dementia in nursing homes (PID): study protocol for a quasi-experimental nurse intervention.

    Science.gov (United States)

    Koppitz, Andrea; Bosshard, Georg; Blanc, Geneviève; Hediger, Hannele; Payne, Sheila; Volken, Thomas

    2017-04-21

    It is estimated that 19 to 83% of people with dementia suffer from pain that is inadequately treated in the last months of life. A large number of healthcare workers who care for these people in nursing homes lack appropriate expertise and may therefore not always recognise, assess and treat pain in those with dementia who have complex problems on time, properly and efficiently. The aim of this intervention trial is to identify care needs of people with dementia suffering from pain living in a nursing home. A quasi-experimental nurse-led intervention trial based on a convenience sample of four nursing homes in the Swiss Canton of Zurich examines the effects on dementia patients (n = 411), the healthcare institution and the qualification level of the healthcare workers compared to historical controls, using an event analysis and a multilevel analysis. Healthcare workers will be individually trained how to assess, intervene and evaluate acute and chronic pain. There are three data-monitoring cycles (T0, T1, T2) and two intervention cycles (I1, I2) with a total study duration of 425 days. There is also a process evaluation based on Dobbins analyses that analyse in particular the potentials for change in clinical practice of change agents. The aim of the intervention trial is to improve pain management strategies in older people with dementia in nursing homes. Clinically significant findings will be expected that will help reduce suffering in the sense of "total pain" for people with dementia. The joint intra- and interdisciplinary collaboration between practice and supply-oriented (nursing) research will have both a lasting effect on the efficiency measurement and provide scientifically sound results. Nursing homes can integrate the findings from the intervention trial into their internal quality control process. The potential for improvements can be directly influenced by the nursing home itself. Registration trial number: DRKS00009726 on DRKS, registered 10

  14. Bone pain caused by swelling of mouse ear capsule static xylene and effects on rat models of cervical spondylosis

    Science.gov (United States)

    Zhang, Xuhui; Xia, Lei; Hao, Shaojun; Chen, Weiliang; Guo, Junyi; Ma, Zhenzhen; Wang, Huamin; Kong, Xuejun; Wang, Hongyu; Zhang, Zhengchen

    2018-04-01

    To observe the effect of intravenous bone pain Capsule on the ear of mice induced by xylene, swelling of rat models of cervical spondylosis. Weighing 18 ˜ 21g 50 mice, male, were randomly divided into for five groups, which were fed with service for bone pain static capsule suspension, Jingfukang granule suspension 0.5%CMC liquid and the same volume of. Respectively to the mice ear drop of xylene 0.05 ml, 4h after cervical dislocation, the mice were sacrificed and the cut two ear, rapid analytical balance weighing, and calculate the ear swelling degree and the other to take the weight of 200 - 60 250g male SD rats, were randomly divided into for 6 groups, 10 rats in each group, of which 5 groups made cervical spondylosis model. Results: with the blank group than bone pain static capsule group and Jingfukang granule group can significantly reduce mouse auricular dimethylbenzene swelling, significantly reduce ear swelling degree (P cervical spondylosis. With the model group ratio, large, medium and small dose of bone pain static capsule group, Jingfukang granule group (P pain static capsule group, Jingfukang granule group can significantly reduce the rat X-ray scores (P pain static capsule can significantly reduce mouse auricular dimethylbenzene swelling. The bone pain capsule has a good effect on the rat model of cervical spondylosis.

  15. The role of fluoxetine on macrophage function in chronic pain (Experimental study in Balb/c mice

    Directory of Open Access Journals (Sweden)

    Dwi Pudjonarko

    2015-11-01

    Full Text Available Chronic pain raises stress conditions such as depression that can lower the cellular immunity. Fluoxetine is an antidepressant  used as an adjuvant in pain management but no one has been linked it with the body immune system. The objectives of this research were to proof the benefits of fluoxetine in  preventing degradation of macrophage function in chronic pain by measuring the macrophage phagocytic index , macrophage NO levels and the liver bacterial count in BALB/c mice infected with Listeria Monocytogenes.A Post Test - Only Control Group Design was conducted using 28 male mice strain BALB /c, age 8-10 weeks. The control group (C, mice got the same standard feed as the other groups. Chronic pain group (P, mice were injected with 20μL intraplantar CFA on day-1. Pain + fluoxetine early group (PFE were treated with P + fluoxetine 5 mg / kg ip day-1, the 4th, the 7th and the 10th, while the Pain + fluoxetine late group (PFL were treated with P + fluoxetine 5 mg / kg ip on day 7th and 10th. All mice were injected with 104 live Listeria monocytogenes iv on day 8th. Termination was performed on day 13th. Differences within groups  were analyzed using  One-way ANOVA and Kruskall Wallis, whereas the correlation of variables were analyzed using  Pearson's product moment. The experimental results showed that The macrophage phagocytic index and NO macrophage level (pg/mL in PFE group(2,24±1,013; 0,24±0,239 was higher than than P group (1,68±0,920; 0,21±0,263 and there was no different in the macrophage phagocytic index of PFE group compared to C group (p=0,583; p=0,805. In PFL group (4,32±1,459; 0,54±0,294 the macrophage phagocytic index as well as NO macrophage level (pg/mL was higher than P group (1,68±0,920; 0,21±0,263 with p=0,002; p=0,017. P group Bacterial count (log cfu/gram (2,30±0,849 was significantly higher than C group(1,15±0,223 (p=0,007, while PFE group bacterial count (1,96±0,653 and PFL group bacterial count (1,84±0

  16. Documentation of pain care processes does not accurately reflect pain management delivered in primary care.

    Science.gov (United States)

    Krebs, Erin E; Bair, Matthew J; Carey, Timothy S; Weinberger, Morris

    2010-03-01

    Researchers and quality improvement advocates sometimes use review of chart-documented pain care processes to assess the quality of pain management. Studies have found that primary care providers frequently fail to document pain assessment and management. To assess documentation of pain care processes in an academic primary care clinic and evaluate the validity of this documentation as a measure of pain care delivered. Prospective observational study. 237 adult patients at a university-affiliated internal medicine clinic who reported any pain in the last week. Immediately after a visit, we asked patients to report the pain treatment they received. Patients completed the Brief Pain Inventory (BPI) to assess pain severity at baseline and 1 month later. We extracted documentation of pain care processes from the medical record and used kappa statistics to assess agreement between documentation and patient report of pain treatment. Using multivariable linear regression, we modeled whether documented or patient-reported pain care predicted change in pain at 1 month. Participants' mean age was 53.7 years, 66% were female, and 74% had chronic pain. Physicians documented pain assessment for 83% of visits. Patients reported receiving pain treatment more often (67%) than was documented by physicians (54%). Agreement between documentation and patient report was moderate for receiving a new pain medication (k = 0.50) and slight for receiving pain management advice (k = 0.13). In multivariable models, documentation of new pain treatment was not associated with change in pain (p = 0.134). In contrast, patient-reported receipt of new pain treatment predicted pain improvement (p = 0.005). Chart documentation underestimated pain care delivered, compared with patient report. Documented pain care processes had no relationship with pain outcomes at 1 month, but patient report of receiving care predicted clinically significant improvement. Chart review measures may not accurately

  17. PAIN AND SUFFERING

    African Journals Online (AJOL)

    reviewed, that pain was a specific sensory modality, having special- ized terminal ... and interesting histological and physiological studies of Weddell and his ... topic for psychological experiment, viz. how an incoming pattern, whatever its .... the clinical accounts of these changes still require a detailed experimental ...

  18. The analgesic effect of tramadol in animal models of neuropathic pain and fibromyalgia.

    Science.gov (United States)

    Kaneko, Kumi; Umehara, Masato; Homan, Takashi; Okamoto, Ken; Oka, Michiko; Oyama, Tatsuya

    2014-03-06

    (±)-Tramadol hydrochloride (tramadol) is a widely used analgesic for the treatment of cancer pain and chronic pain. Although many animal studies have shown antinociceptive effects of tramadol in both acute and chronic pain, little is known about the effect of tramadol in putative animal models of fibromyalgia. In this study, we compared the antiallodynic effects of oral administration of tramadol in two kinds of rat chronic pain models, neuropathic pain induced by partial sciatic nerve ligation (PSL) and reserpine-induced myalgia (RIM). In PSL rats, the threshold for responses induced by tactile stimulation with von Frey filaments was significantly decreased seven days after the operation, suggesting that the operation induced tactile allodynia. Orally administered tramadol showed a potent and dose-dependent antiallodynic effect on PSL-induced allodynia. In RIM rats, the threshold was significantly decreased five days after reserpine treatment. Orally administered tramadol also attenuated reserpine-induced tactile allodynia. To explore the mechanism of the antiallodynic effect of tramadol in RIM rats, we investigated the effect of the opioid antagonist naloxone on the tramadol-induced analgesic effect in these rats. The effect of tramadol was partially antagonized by naloxone, suggesting that the opioid receptor is involved at least in part in the antiallodynic effect of tramadol in RIM rats. These data indicate that orally administered tramadol produced improvement in both PSL rats and RIM rats at similar doses and provide evidence that the opioid system is partly involved in the analgesic effect of tramadol in RIM rats. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  19. The Effects of Sleep Deprivation on Pain

    OpenAIRE

    Kundermann, Bernd; Krieg, Jürgen-Christian; Schreiber, Wolfgang; Lautenbacher, Stefan

    2004-01-01

    Chronic pain syndromes are associated with alterations in sleep continuity and sleep architecture. One perspective of this relationship, which has not received much attention to date, is that disturbances of sleep affect pain. To fathom this direction of cause, experimental human and animal studies on the effects of sleep deprivation on pain processing were reviewed. According to the majority of the studies, sleep deprivation produces hyperalgesic changes. Furthermore, sleep deprivation can c...

  20. Behavioral testing in rodent models of orofacial neuropathic and inflammatory pain

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    Krzyzanowska, Agnieszka; Avendaño, Carlos

    2012-01-01

    Orofacial pain conditions are often very debilitating to the patient and difficult to treat. While clinical interest is high, the proportion of studies performed in the orofacial region in laboratory animals is relatively low, compared with other body regions. This is partly due to difficulties in testing freely moving animals and therefore lack of reliable testing methods. Here we present a comprehensive review of the currently used rodent models of inflammatory and neuropathic pain adapted to the orofacial areas, taking into account the difficulties and drawbacks of the existing approaches. We examine the available testing methods and procedures used for assessing the behavioral responses in the face in both mice and rats and provide a summary of some pharmacological agents used in these paradigms to date. The use of these agents in animal models is also compared with outcomes observed in the clinic. PMID:23139912

  1. Topical gabapentin gel alleviates allodynia and hyperalgesia in the chronic sciatic nerve constriction injury neuropathic pain model.

    Science.gov (United States)

    Shahid, M; Subhan, F; Ahmad, N; Ali, G; Akbar, S; Fawad, K; Sewell, R D E

    2017-04-01

    Systemic gabapentin is a mainstay treatment for neuropathic pain though there are side-effects. Localized therapy may curtail such side-effects so a topical gabapentin dermal application was examined in the chronic constriction injury (CCI) model of neuropathic pain. Partial denervation CCI was achieved by rat sciatic nerve ligation. Gabapentin gel (10% w/w) was applied three times daily on the ipsilateral or contralateral plantar surface of the hind-paw, whereas in a concurrent systemic study, gabapentin was intraperitoneally administered daily (75 mg/kg) for 30 days. Tests for static- and dynamic-mechano-allodynia [paw withdrawal threshold (PWT) to von Frey filament application and latency (PWL) to light brushing], cold-allodynia [paw withdrawal duration (PWD) to acetone], heat- (PWL and PWD) and mechano-hyperalgesia (PWD to pin prick) were utilized to assess pain, whereas effects on locomotion (open field) and motor balance (rotarod and footprint analysis) were measured on days 5-30 post surgery. Topical application of gabapentin gel ipsilaterally but not contralaterally alleviated CCI-induced static- (days 10-30) and dynamic-allodynia (days 15-30), suppressed cold-allodynia (days 10-30), heat- (days 15-30) and mechano-hyperalgesia (days 5-30) indicating a local action. Systemic gabapentin exhibited similar pain profiles but was associated with motor impairment. The gabapentin gel formulation afforded desirable neuropathic pain alleviating effects devoid of unwanted systemic side-effects. These outcomes disclose an expedient pharmacological validation of the effectiveness of topical gabapentin gel against an extensive range of nociceptive stimulus modalities utilizing the CCI-induced neuropathic pain model. They also advocate further clinical studies on topical gabapentin with regard to certain neuropathic pain syndromes. Systemic gabapentin neuropathic pain management carries side-effects ostensibly preventable by localized therapy. This study validates the

  2. Neurochemical dynamics of acute orofacial pain in the human trigeminal brainstem nuclear complex.

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    de Matos, Nuno M P; Hock, Andreas; Wyss, Michael; Ettlin, Dominik A; Brügger, Mike

    2017-11-15

    The trigeminal brainstem sensory nuclear complex is the first central relay structure mediating orofacial somatosensory and nociceptive perception. Animal studies suggest a substantial involvement of neurochemical alterations at such basal CNS levels in acute and chronic pain processing. Translating this animal based knowledge to humans is challenging. Human related examining of brainstem functions are challenged by MR related peculiarities as well as applicability aspects of experimentally standardized paradigms. Based on our experience with an MR compatible human orofacial pain model, the aims of the present study were twofold: 1) from a technical perspective, the evaluation of proton magnetic resonance spectroscopy at 3 T regarding measurement accuracy of neurochemical profiles in this small brainstem nuclear complex and 2) the examination of possible neurochemical alterations induced by an experimental orofacial pain model. Data from 13 healthy volunteers aged 19-46 years were analyzed and revealed high quality spectra with significant reductions in total N-acetylaspartate (N-acetylaspartate + N-acetylaspartylglutamate) (-3.7%, p = 0.009) and GABA (-10.88%, p = 0.041) during the pain condition. These results might reflect contributions of N-acetylaspartate and N-acetylaspartylglutamate in neuronal activity-dependent physiologic processes and/or excitatory neurotransmission, whereas changes in GABA might indicate towards a reduction in tonic GABAergic functioning during nociceptive signaling. Summarized, the present study indicates the applicability of 1 H-MRS to obtain neurochemical dynamics within the human trigeminal brainstem sensory nuclear complex. Further developments are needed to pave the way towards bridging important animal based knowledge with human research to understand the neurochemistry of orofacial nociception and pain. Copyright © 2017 Elsevier Inc. All rights reserved.

  3. Patient-centered professional practice models for managing low back pain in older adults: a pilot randomized controlled trial.

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    Goertz, Christine M; Salsbury, Stacie A; Long, Cynthia R; Vining, Robert D; Andresen, Andrew A; Hondras, Maria A; Lyons, Kevin J; Killinger, Lisa Z; Wolinsky, Fredric D; Wallace, Robert B

    2017-10-13

    Low back pain is a debilitating condition for older adults, who may seek healthcare from multiple providers. Few studies have evaluated impacts of different healthcare delivery models on back pain outcomes in this population. The purpose of this study was to compare clinical outcomes of older adults receiving back pain treatment under 3 professional practice models that included primary medical care with or without chiropractic care. We conducted a pilot randomized controlled trial with 131 community-dwelling, ambulatory older adults with subacute or chronic low back pain. Participants were randomly allocated to 12 weeks of individualized primary medical care (Medical Care), concurrent medical and chiropractic care (Dual Care), or medical and chiropractic care with enhanced interprofessional collaboration (Shared Care). Primary outcomes were low back pain intensity rated on the numerical rating scale and back-related disability measured with the Roland-Morris Disability Questionnaire. Secondary outcomes included clinical measures, adverse events, and patient satisfaction. Statistical analyses included mixed-effects regression models and general estimating equations. At 12 weeks, participants in all three treatment groups reported improvements in mean average low back pain intensity [Shared Care: 1.8; 95% confidence interval (CI) 1.0 to 2.6; Dual Care: 3.0; 95% CI 2.3 to 3.8; Medical Care: 2.3; 95% CI 1.5 to 3.2)] and back-related disability (Shared Care: 2.8; 95% CI 1.6 to 4.0; Dual Care: 2.5; 95% CI 1.3 to 3.7; Medical Care: 1.5; 95% CI 0.2 to 2.8). No statistically significant differences were noted between the three groups on the primary measures. Participants in both models that included chiropractic reported significantly better perceived low back pain improvement, overall health and quality of life, and greater satisfaction with healthcare services than patients who received medical care alone. Professional practice models that included primary care and

  4. Melatonin Alters the Mechanical and Thermal Hyperalgesia Induced by Orofacial Pain Model in Rats.

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    Scarabelot, Vanessa Leal; Medeiros, Liciane Fernandes; de Oliveira, Carla; Adachi, Lauren Naomi Spezia; de Macedo, Isabel Cristina; Cioato, Stefania Giotti; de Freitas, Joice S; de Souza, Andressa; Quevedo, Alexandre; Caumo, Wolnei; Torres, Iraci Lucena da Silva

    2016-10-01

    Melatonin is a neuroendocrine hormone that presents a wide range of physiological functions including regulating circadian rhythms and sleep, enhancing immune function, sleep improvement, and antioxidant effects. In addition, melatonin has received special attention in pain treatment since it is effective and presents few adverse effects. In this study, we evaluated the effect of acute dose of melatonin upon hyperalgesia induced by complete Freund's adjuvant in a chronic orofacial pain model in Sprague-Dawley rats. Nociceptive behavior was assessed by facial Von Frey and the hot plate tests at baseline and thereafter 30, 60, and 120 min, 24 h, and 7 days after melatonin treatment. We demonstrated that acute melatonin administration alters mechanical and thermal hyperalgesia induced by an orofacial pain model (TMD), highlighting that the melatonin effect upon mechanical hyperalgesia remained until 7 days after its administration. Besides, we observed specific tissue profiles of neuroimmunomodulators linked to pain conditions and/or melatonin effect (brain-derived neurotrophic factor, nerve growth factor, and interleukins 6 and 10) in the brainstem levels, and its effects were state-dependent of the baseline of these animals.

  5. A Preliminary Genome-Wide Association Study of Pain-Related Fear: Implications for Orofacial Pain

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    Cameron L. Randall

    2017-01-01

    Full Text Available Background. Acute and chronic orofacial pain can significantly impact overall health and functioning. Associations between fear of pain and the experience of orofacial pain are well-documented, and environmental, behavioral, and cognitive components of fear of pain have been elucidated. Little is known, however, regarding the specific genes contributing to fear of pain. Methods. A genome-wide association study (GWAS; N=990 was performed to identify plausible genes that may predispose individuals to various levels of fear of pain. The total score and three subscales (fear of minor, severe, and medical/dental pain of the Fear of Pain Questionnaire-9 (FPQ-9 were modeled in a variance components modeling framework to test for genetic association with 8.5 M genetic variants across the genome, while adjusting for sex, age, education, and income. Results. Three genetic loci were significantly associated with fear of minor pain (8q24.13, 8p21.2, and 6q26; p<5×10-8 for all near the genes TMEM65, NEFM, NEFL, AGPAT4, and PARK2. Other suggestive loci were found for the fear of pain total score and each of the FPQ-9 subscales. Conclusions. Multiple genes were identified as possible candidates contributing to fear of pain. The findings may have implications for understanding and treating chronic orofacial pain.

  6. Equal pain – Unequal fear response: Enhanced susceptibility of tooth pain to fear conditioning

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    Michael Lukas Meier

    2014-07-01

    Full Text Available Experimental fear conditioning in humans is widely used as a model to investigate the neural basis of fear learning and to unravel the pathogenesis of anxiety disorders. It has been observed that fear conditioning depends on stimulus salience and subject vulnerability to fear. It is further known that the prevalence of dental-related fear and phobia is exceedingly high in the population. Dental phobia is unique as no other body part is associated with a specific phobia. Therefore, we hypothesized that painful dental stimuli exhibit an enhanced susceptibility to fear conditioning when comparing to equal perceived stimuli applied to other body sites. Differential susceptibility to pain-related fear was investigated by analyzing responses to an unconditioned stimulus (UCS applied to the right maxillary canine (UCS-c versus the right tibia (UCS-t. For fear conditioning, UCS-c and USC-t consisted of painful electric stimuli, carefully matched at both application sites for equal intensity and quality perception. UCSs were paired to simple geometrical forms which served as conditioned stimuli (CS+. Unpaired CS+ were presented for eliciting and analyzing conditioned fear responses. Outcome parameter were 1 skin conductance changes and 2 time-dependent brain activity (BOLD responses in fear-related brain regions such as the amygdala, anterior cingulate cortex, insula, thalamus, orbitofrontal cortex and medial prefrontal cortex.A preferential susceptibility of dental pain to fear conditioning was observed, reflected by heightened skin conductance responses and enhanced time-dependent brain activity (BOLD responses in the fear network. For the first time, this study demonstrates fear-related neurobiological mechanisms that point towards a superior conditionability of tooth pain. Beside traumatic dental experiences our results offer novel evidence that might explain the high prevalence of dental-related fears in the population.

  7. Poly(ADP-ribose polymerase inhibition reveals a potential mechanism to promote neuroprotection and treat neuropathic pain

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    Prashanth Komirishetty

    2016-01-01

    Full Text Available Neuropathic pain is triggered by the lesions to peripheral nerves which alter their structure and function. Neuroprotective approaches that limit the pathological changes and improve the behavioral outcome have been well explained in different experimental models of neuropathy but translation of such strategies to clinics has been disappointing. Experimental evidences revealed the role of free radicals, especially peroxynitrite after the nerve injury. They provoke oxidative DNA damage and consequent over-activation of the poly(ADP-ribose polymerase (PARP upregulates pro-inflammatory pathways, causing bioenergetic crisis and neuronal death. Along with these changes, it causes mitochondrial dysfunction leading to neuronal apoptosis. In related preclinical studies agents that neutralize the free radicals and pharmacological inhibitors of PARP have shown benefits in treating experimental neuropathy. This article reviews the involvement of PARP over-activation in trauma induced neuropathy and therapeutic significance of PARP inhibitors in the experimental neuropathy and neuropathic pain.

  8. Poly(ADP-ribose) polymerase inhibition reveals a potential mechanism to promote neuroprotection and treat neuropathic pain.

    Science.gov (United States)

    Komirishetty, Prashanth; Areti, Aparna; Gogoi, Ranadeep; Sistla, Ramakrishna; Kumar, Ashutosh

    2016-10-01

    Neuropathic pain is triggered by the lesions to peripheral nerves which alter their structure and function. Neuroprotective approaches that limit the pathological changes and improve the behavioral outcome have been well explained in different experimental models of neuropathy but translation of such strategies to clinics has been disappointing. Experimental evidences revealed the role of free radicals, especially peroxynitrite after the nerve injury. They provoke oxidative DNA damage and consequent over-activation of the poly(ADP-ribose) polymerase (PARP) upregulates pro-inflammatory pathways, causing bioenergetic crisis and neuronal death. Along with these changes, it causes mitochondrial dysfunction leading to neuronal apoptosis. In related preclinical studies agents that neutralize the free radicals and pharmacological inhibitors of PARP have shown benefits in treating experimental neuropathy. This article reviews the involvement of PARP over-activation in trauma induced neuropathy and therapeutic significance of PARP inhibitors in the experimental neuropathy and neuropathic pain.

  9. Chronic Pelvic Pain Development and Prostate Inflammation in Strains of Mice With Different Susceptibility to Experimental Autoimmune Prostatitis.

    Science.gov (United States)

    Breser, Maria L; Motrich, Ruben D; Sanchez, Leonardo R; Rivero, Virginia E

    2017-01-01

    Experimental autoimmune prostatitis (EAP) is an autoimmune inflammatory disease of the prostate characterized by peripheral prostate-specific autoimmune responses associated with prostate inflammation. EAP is induced in rodents upon immunization with prostate antigens (PAg) plus adjuvants and shares important clinical and immunological features with the human disease chronic prostatitis/chronic pelvic pain syndrome (CP/CPPS). EAP was induced in young NOD, C57BL/6, and BALB/c male mice by immunization with PAg plus complete Freund́s adjuvant. Tactile allodynia was assessed using Von Frey fibers as a measure of pelvic pain at baseline and at different time points after immunization. Using conventional histology, immunohistochemistry, FACS analysis, and protein arrays, an interstrain comparative study of prostate cell infiltration and inflammation was performed. Chronic pelvic pain development was similar between immunized NOD and C57BL/6 mice, although the severity of leukocyte infiltration was greater in the first case. Coversely, minimal prostate cell infiltration was observed in immunized BALB/c mice, who showed no pelvic pain development. Increased numbers of mast cells, mostly degranulated, were detected in prostate samples from NOD and C57BL/6 mice, while lower total counts and resting were observed in BALB/c mice. Prostate tissue from NOD mice revealed markedly increased expression levels of inflammatory cytokines, chemokines, adhesion molecules, vascular endothelial growth factor, and metalloproteinases. Similar results, but to a lesser extent, were observed when analyzing prostate tissue from C57BL/6 mice. On the contrary, the expression of the above mediators was very low in prostate tissue from immunized BALB/c mice, showing significantly slight increments only for CXCL1 and IL4. Our results provide new evidence indicating that NOD, C57BL/6, and BALB/c mice develop different degrees of chronic pelvic pain, type, and amount of prostate cell infiltration

  10. Pain point system scale (PPSS: a method for postoperative pain estimation in retrospective studies

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    Gkotsi A

    2012-11-01

    Full Text Available Anastasia Gkotsi,1 Dimosthenis Petsas,2 Vasilios Sakalis,3 Asterios Fotas,3 Argyrios Triantafyllidis,3 Ioannis Vouros,3 Evangelos Saridakis,2 Georgios Salpiggidis,3 Athanasios Papathanasiou31Department of Experimental Physiology, Aristotle University of Thessaloniki, Thessaloniki, Greece; 2Department of Anesthesiology, 3Department of Urology, Hippokration General Hospital, Thessaloniki, GreecePurpose: Pain rating scales are widely used for pain assessment. Nevertheless, a new tool is required for pain assessment needs in retrospective studies.Methods: The postoperative pain episodes, during the first postoperative day, of three patient groups were analyzed. Each pain episode was assessed by a visual analog scale, numerical rating scale, verbal rating scale, and a new tool – pain point system scale (PPSS – based on the analgesics administered. The type of analgesic was defined based on the authors’ clinic protocol, patient comorbidities, pain assessment tool scores, and preadministered medications by an artificial neural network system. At each pain episode, each patient was asked to fill the three pain scales. Bartlett’s test and Kaiser–Meyer–Olkin criterion were used to evaluate sample sufficiency. The proper scoring system was defined by varimax rotation. Spearman’s and Pearson’s coefficients assessed PPSS correlation to the known pain scales.Results: A total of 262 pain episodes were evaluated in 124 patients. The PPSS scored one point for each dose of paracetamol, three points for each nonsteroidal antiinflammatory drug or codeine, and seven points for each dose of opioids. The correlation between the visual analog scale and PPSS was found to be strong and linear (rho: 0.715; P <0.001 and Pearson: 0.631; P < 0.001.Conclusion: PPSS correlated well with the known pain scale and could be used safely in the evaluation of postoperative pain in retrospective studies.Keywords: pain scale, retrospective studies, pain point system

  11. A psychophysical study of endogenous analgesia: the role of the conditioning pain in the induction and magnitude of conditioned pain modulation.

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    Nir, Rony-Reuven; Granovsky, Yelena; Yarnitsky, David; Sprecher, Elliot; Granot, Michal

    2011-05-01

    Endogenous analgesia (EA) can be examined experimentally using a conditioned pain modulation (CPM) paradigm. While noxious conditioning stimulation intensities (CSIs) are mainly used, it has not been fully investigated in the same experimental design whether the experienced conditioning pain level affects CPM responses. The principal goal of the present study was to characterize CPM induction and magnitudes evoked by various conditioning pain levels. Furthermore, we explored associations between conditioning pain reports and CPM responses across various CSIs. Thirty healthy, young, right-handed males were tested with a parallel CPM paradigm. Three different CSIs (hand water-immersion) induced mild, moderate and intense pain levels, rated 12.41 ± 7.85, 31.57 ± 9.56 and 58.1 ± 11.43, respectively (0-100 numerical pain scale) (P < 0.0001). Contact-heat 'test-stimulus' levels were compared before and during conditioning. Within the group, (i) CPM was induced only by the moderate and intense CSIs (Ps ≤ 0.001); (ii) no difference was demonstrated between the magnitudes of these CPM responses. Regression analysis revealed that CPM induction was independent of the perceived conditioning pain level, but associated with the absolute CSI (P < 0.0001). Conditioning pain levels were correlated across all CSIs, as were CPM magnitudes (Ps ≤ 0.01). We conclude that among males, (i) once a CPM response is evoked by a required conditioning pain experience, its magnitude is not further affected by increasing conditioning pain and (ii) CPM magnitudes are inter-correlated, but unrelated to conditioning pain reports. These observations may suggest that CPM responses represent an intrinsic element of an individual's EA processes, which are not significantly affected by the experienced conditioning pain. Copyright © 2010 European Federation of International Association for the Study of Pain Chapters. Published by Elsevier Ltd. All rights reserved.

  12. Preventive Treatment with Ketamine Attenuates the Ischaemia-Reperfusion Response in a Chronic Postischaemia Pain Model

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    Suryamin Liman

    2015-01-01

    Full Text Available Ischemia and inflammation may be pathophysiological mechanisms of complex regional pain syndrome (CRPS. Ketamine has proposed anti-inflammatory effects and has been used for treating CRPS. This study aimed to evaluate anti-inflammatory and analgesic effects of ketamine after ischaemia-reperfusion injury in a chronic postischaemia pain (CPIP model of CRPS-I. Using this model, ischemia was induced in the hindlimbs of male Sprague-Dawley rats. Ketamine, methylprednisolone, or saline was administered immediately after reperfusion. Physical effects, (oedema, temperature, and mechanical and cold allodynia in the bilateral hindpaws, were assessed from 48 hours after reperfusion. Fewer (56% rats in the ketamine group developed CPIP at the 48th hour after reperfusion (nonsignificant. Ketamine treated rats showed a significantly lower temperature in the ischaemic hindpaw compared to saline (P<0.01 and methylprednisolone (P<0.05 groups. Mechanical and cold allodynia were significantly lower in the ischaemic side in the ketamine group (P<0.05. Proinflammatory cytokines TNF-α and IL-2 were significantly lower at the 48th hour after reperfusion in ketamine and methylprednisolone groups, compared to saline (all P<0.05. In conclusion, immediate administration of ketamine after an ischaemia-reperfusion injury can alleviate pain and inflammation in the CPIP model and has potential to treat postischaemic pain.

  13. Comparative Analysis of Pain Behaviours in Humanized Mouse Models of Sickle Cell Anemia.

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    Jianxun Lei

    Full Text Available Pain is a hallmark feature of sickle cell anemia (SCA but management of chronic as well as acute pain remains a major challenge. Mouse models of SCA are essential to examine the mechanisms of pain and develop novel therapeutics. To facilitate this effort, we compared humanized homozygous BERK and Townes sickle mice for the effect of gender and age on pain behaviors. Similar to previously characterized BERK sickle mice, Townes sickle mice show more mechanical, thermal, and deep tissue hyperalgesia with increasing age. Female Townes sickle mice demonstrate more hyperalgesia compared to males similar to that reported for BERK mice and patients with SCA. Mechanical, thermal and deep tissue hyperalgesia increased further after hypoxia/reoxygenation (H/R treatment in Townes sickle mice. Together, these data show BERK sickle mice exhibit a significantly greater degree of hyperalgesia for all behavioral measures as compared to gender- and age-matched Townes sickle mice. However, the genetically distinct "knock-in" strategy of human α and β transgene insertion in Townes mice as compared to BERK mice, may provide relative advantage for further genetic manipulations to examine specific mechanisms of pain.

  14. Experimental pain ratings and reactivity of cortisol and soluble tumor necrosis factor-α receptor II following a trial of hypnosis: Results of a randomized controlled pilot study

    Science.gov (United States)

    Goodin, Burel R.; Quinn, Noel B.; Kronfli, Tarek; King, Christopher D.; Page, Gayle G.; Haythornthwaite, Jennifer A.; Edwards, Robert R.; Stapleton, Laura M.; McGuire, Lynanne

    2011-01-01

    Objective Current evidence supports the efficacy of hypnosis for reducing the pain associated with experimental stimulation and various acute and chronic conditions; however, the mechanisms explaining how hypnosis exerts its effects remain less clear. The hypothalamic-pituitary-adrenal (HPA) axis and pro-inflammatory cytokines represent potential targets for investigation given their purported roles in the perpetuation of painful conditions; yet, no clinical trials have thus far examined the influence of hypnosis on these mechanisms. Design Healthy participants, highly susceptible to the effects of hypnosis, were randomized to either a hypnosis intervention or a no-intervention control. Using a cold pressor task, assessments of pain intensity and pain unpleasantness were collected prior to the intervention (Pre) and following the intervention (Post) along with pain-provoked changes in salivary cortisol and the soluble receptor of tumor necrosis factor-α (sTNFαRII). Results Compared to the no-intervention control, data analyses revealed that hypnosis significantly reduced pain intensity and pain unpleasantness. Hypnosis was not significantly associated with suppression of cortisol or sTNFαRII reactivity to acute pain from Pre to Post; however, the effect sizes for these associations were medium-sized. Conclusions Overall, the findings from this randomized controlled pilot study support the importance of a future large-scale study on the effects of hypnosis for modulating pain-related changes of the HPA axis and pro-inflammatory cytokines. PMID:22233394

  15. An Evaluation Model for a Multidisciplinary Chronic Pelvic Pain Clinic: Application of the RE-AIM Framework.

    Science.gov (United States)

    Chen, Innie; Money, Deborah; Yong, Paul; Williams, Christina; Allaire, Catherine

    2015-09-01

    Chronic pelvic pain (CPP) is a prevalent, debilitating, and costly condition. Although national guidelines and empiric evidence support the use of a multidisciplinary model of care for such patients, such clinics are uncommon in Canada. The BC Women's Centre for Pelvic Pain and Endometriosis was created to respond to this need, and there is interest in this model of care's impact on the burden of disease in British Columbia. We sought to create an approach to its evaluation using the RE-AIM (Reach, Efficacy, Adoption, Implementation, Maintenance) evaluation framework to assess the impact of the care model and to guide clinical decision-making and policy. The RE-AIM evaluation framework was applied to consider the different dimensions of impact of the BC Centre. The proposed measures, data sources, and data management strategies for this mixed-methods approach were identified. The five dimensions of impact were considered at individual and organizational levels, and corresponding indicators were proposed to enable integration into existing data infrastructure to facilitate collection and early program evaluation. The RE-AIM framework can be applied to the evaluation of a multidisciplinary chronic pelvic pain clinic. This will allow better assessment of the impact of innovative models of care for women with chronic pelvic pain.

  16. Effect of pain chronification and chronic pain on an endogenous pain modulation circuit in rats.

    Science.gov (United States)

    Miranda, J; Lamana, S M S; Dias, E V; Athie, M; Parada, C A; Tambeli, C H

    2015-02-12

    We tested the hypothesis that chronic pain development (pain chronification) and ongoing chronic pain (chronic pain) reduce the activity and induce plastic changes in an endogenous analgesia circuit, the ascending nociceptive control. An important mechanism mediating this form of endogenous analgesia, referred to as capsaicin-induced analgesia, is its dependence on nucleus accumbens μ-opioid receptor mechanisms. Therefore, we also investigated whether pain chronification and chronic pain alter the requirement for nucleus accumbens μ-opioid receptor mechanisms in capsaicin-induced analgesia. We used an animal model of pain chronification in which daily subcutaneous prostaglandin E2 (PGE2) injections into the rat's hind paw for 14 days, referred to as the induction period of persistent hyperalgesia, induce a long-lasting state of nociceptor sensitization referred to as the maintenance period of persistent hyperalgesia, that lasts for at least 30 days following the cessation of the PGE2 treatment. The nociceptor hypersensitivity was measured by the shortening of the time interval for the animal to respond to a mechanical stimulation of the hind paw. We found a significant reduction in the duration of capsaicin-induced analgesia during the induction and maintenance period of persistent mechanical hyperalgesia. Intra-accumbens injection of the μ-opioid receptor selective antagonist Cys(2),Tyr(3),Orn(5),Pen(7)amide (CTOP) 10 min before the subcutaneous injection of capsaicin into the rat's fore paw blocked capsaicin-induced analgesia. Taken together, these findings indicate that pain chronification and chronic pain reduce the duration of capsaicin-induced analgesia, without affecting its dependence on nucleus accumbens μ-opioid receptor mechanisms. The attenuation of endogenous analgesia during pain chronification and chronic pain suggests that endogenous pain circuits play an important role in the development and maintenance of chronic pain. Copyright © 2014 IBRO

  17. Effects of Flotation-REST on Muscle Tension Pain

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    Anette Kjellgren

    2001-01-01

    Full Text Available The purpose of the present study was to investigate whether the floating form of the restricted environmental stimulation technique (REST may be applied within the field of pain relief. Flotation-REST consists of a procedure whereby an individual is immersed in a tank filled with water of an extremely high salt concentration. Thirty-seven patients (14 men and 23 women suffering from chronic pain consisting of aching muscles in the neck and back area participated in the study. They were randomly assigned to either a control group (17 participants or an experimental group (20 participants. The experimental group received nine opportunities to use the flotation-REST technique in the water tank over a three-week period. The results indicated that the most severe perceived pain intensity was significantly reduced, whereas low perceived pain intensity was not influenced by the floating technique. Further, the results indicated that circulating levels of the noradrenaline metabolite 3-methoxy-4-hydroxyphenylethyleneglycol were reduced significantly in the experimental group but not in the control group following treatment, whereas endorphin levels were not affected by flotation. Flotation-REST treatment also elevated the participants' optimism and reduced the degree of anxiety or depression; at nighttime, patients who underwent flotation fell asleep more easily. The present findings describe possible changes, for the better, in patients presenting with chronic pain complaints.

  18. Effects of flotation-REST on muscle tension pain.

    Science.gov (United States)

    Kjellgren, A; Sundequist, U; Norlander, T; Archer, T

    2001-01-01

    The purpose of the present study was to investigate whether the floating form of the restricted environmental stimulation technique (REST) may be applied within the field of pain relief. Flotation-REST consists of a procedure whereby an individual is immersed in a tank filled with water of an extremely high salt concentration. Thirty-seven patients (14 men and 23 women) suffering from chronic pain consisting of aching muscles in the neck and back area participated in the study. They were randomly assigned to either a control group (17 participants) or an experimental group (20 participants). The experimental group received nine opportunities to use the flotation-REST technique in the water tank over a three-week period. The results indicated that the most severe perceived pain intensity was significantly reduced, whereas low perceived pain intensity was not influenced by the floating technique. Further, the results indicated that circulating levels of the noradrenaline metabolite 3-methoxy-4-hydroxyphenylethyleneglycol were reduced significantly in the experimental group but not in the control group following treatment, whereas endorphin levels were not affected by flotation. Flotation-REST treatment also elevated the participants' optimism and reduced the degree of anxiety or depression; at nighttime, patients who underwent flotation fell asleep more easily. The present findings describe possible changes, for the better, in patients presenting with chronic pain complaints.

  19. Mindfulness meditation–based pain relief: a mechanistic account

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    Zeidan, Fadel; Vago, David

    2016-01-01

    Pain is a multidimensional experience that involves sensory, cognitive, and affective factors. The constellation of interactions between these factors renders the treatment of chronic pain challenging and financially burdensome. Further, the widespread use of opioids to treat chronic pain has led to an opioid epidemic characterized by exponential growth in opioid misuse and addiction. The staggering statistics related to opioid use highlight the importance of developing, testing, and validating fast-acting nonpharmacological approaches to treat pain. Mindfulness meditation is a technique that has been found to significantly reduce pain in experimental and clinical settings. The present review delineates findings from recent studies demonstrating that mindfulness meditation significantly attenuates pain through multiple, unique mechanisms—an important consideration for the millions of chronic pain patients seeking narcotic-free, self-facilitated pain therapy. PMID:27398643

  20. Developing Phenomena Models from Experimental Data

    DEFF Research Database (Denmark)

    Kristensen, Niels Rode; Madsen, Henrik; Jørgensen, Sten Bay

    2003-01-01

    A systematic approach for developing phenomena models from experimental data is presented. The approach is based on integrated application of stochastic differential equation (SDE) modelling and multivariate nonparametric regression, and it is shown how these techniques can be used to uncover...... unknown functionality behind various phenomena in first engineering principles models using experimental data. The proposed modelling approach has significant application potential, e.g. for determining unknown reaction kinetics in both chemical and biological processes. To illustrate the performance...... of the approach, a case study is presented, which shows how an appropriate phenomena model for the growth rate of biomass in a fed-batch bioreactor can be inferred from data....

  1. Developing Phenomena Models from Experimental Data

    DEFF Research Database (Denmark)

    A systematic approach for developing phenomena models from experimental data is presented. The approach is based on integrated application of stochastic differential equation (SDE) modelling and multivariate nonparametric regression, and it is shown how these techniques can be used to uncover...... unknown functionality behind various phenomena in first engineering principles models using experimental data. The proposed modelling approach has significant application potential, e.g. for determining unknown reaction kinetics in both chemical and biological processes. To illustrate the performance...... of the approach, a case study is presented, which shows how an appropriate phenomena model for the growth rate of biomass in a fed-batch bioreactor can be inferred from data....

  2. Increasing Optimism Protects Against Pain-Induced Impairment in Task-Shifting Performance.

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    Boselie, Jantine J L M; Vancleef, Linda M G; Peters, Madelon L

    2017-04-01

    Persistent pain can lead to difficulties in executive task performance. Three core executive functions that are often postulated are inhibition, updating, and shifting. Optimism, the tendency to expect that good things happen in the future, has been shown to protect against pain-induced performance deterioration in executive function updating. This study tested whether this protective effect of a temporary optimistic state by means of a writing and visualization exercise extended to executive function shifting. A 2 (optimism: optimism vs no optimism) × 2 (pain: pain vs no pain) mixed factorial design was conducted. Participants (N = 61) completed a shifting task once with and once without concurrent painful heat stimulation after an optimism or neutral manipulation. Results showed that shifting performance was impaired when experimental heat pain was applied during task execution, and that optimism counteracted pain-induced deterioration in task-shifting performance. Experimentally-induced heat pain impairs shifting task performance and manipulated optimism or induced optimism counteracted this pain-induced performance deterioration. Identifying psychological factors that may diminish the negative effect of persistent pain on the ability to function in daily life is imperative. Copyright © 2016 American Pain Society. Published by Elsevier Inc. All rights reserved.

  3. Local ASIC3 modulates pain and disease progression in a rat model of osteoarthritis

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    Izumi Masashi

    2012-08-01

    Full Text Available Abstract Background Recent data have suggested a relationship between acute arthritic pain and acid sensing ion channel 3 (ASIC3 on primary afferent fibers innervating joints. The purpose of this study was to clarify the role of ASIC3 in a rat model of osteoarthritis (OA which is considered a degenerative rather than an inflammatory disease. Methods We induced OA via intra-articular mono-iodoacetate (MIA injection, and evaluated pain-related behaviors including weight bearing measured with an incapacitance tester and paw withdrawal threshold in a von Frey hair test, histology of affected knee joint, and immunohistochemistry of knee joint afferents. We also assessed the effect of ASIC3 selective peptide blocker (APETx2 on pain behavior, disease progression, and ASIC3 expression in knee joint afferents. Results OA rats showed not only weight-bearing pain but also mechanical hyperalgesia outside the knee joint (secondary hyperalgesia. ASIC3 expression in knee joint afferents was significantly upregulated approximately twofold at Day 14. Continuous intra-articular injections of APETx2 inhibited weight distribution asymmetry and secondary hyperalgesia by attenuating ASIC3 upregulation in knee joint afferents. Histology of ipsilateral knee joint showed APETx2 worked chondroprotectively if administered in the early, but not late phase. Conclusions Local ASIC3 immunoreactive nerve is strongly associated with weight-bearing pain and secondary hyperalgesia in MIA-induced OA model. APETx2 inhibited ASIC3 upregulation in knee joint afferents regardless of the time-point of administration. Furthermore, early administration of APETx2 prevented cartilage damage. APETx2 is a novel, promising drug for OA by relieving pain and inhibiting disease progression.

  4. Human milk for neonatal pain relief during ophthalmoscopy

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    Laiane Medeiros Ribeiro

    2013-10-01

    Full Text Available Ophthalmoscopy performed for the early diagnosis of retinopathy of prematurity (ROP is painful for preterm infants, thus necessitating interventions for minimizing pain. The present study aimed to establish the effectiveness of human milk, compared with sucrose, for pain relief in premature infants subjected to ophthalmoscopy for the early diagnosis of ROP. This investigation was a pilot, quasi-experimental study conducted with 14 premature infants admitted to the neonatal intensive care unit (NICU of a university hospital. Comparison between the groups did not yield a statistically significant difference relative to the crying time, salivary cortisol, or heart rate (HR. Human milk appears to be as effective as sucrose in relieving acute pain associated with ophthalmoscopy. The study’s limitations included its small sample size and lack of randomization. Experimental investigations with greater sample power should be performed to reinforce the evidence found in the present study.

  5. Reducing Postoperative Pain from Tonsillectomy Using Monopolar Electrocautery by Cooling the Oropharynx

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    Vieira, Lucas

    2014-01-01

    Full Text Available Objective Evaluate intraoperative cooling of the oropharynx to reduce postoperative pain in tonsillectomy using monopolar electrocautery. Methods Sixty-six patients, age 1 to 12 years, were selected for the study, 33 in the control group and 33 in the experimental group. After randomization, patients underwent subcapsular dissection and hemostasis with monopolar electrocautery. Patients in the experimental group had the oropharynx cooled after tonsil dissection and hemostasis for 10 minutes. The procedure was done through the oral cavity by irrigation with 500 mL of 0.9% saline, in temperatures between 5°C and 10°C, for 5 minutes. The evaluation of postoperative pain was made with the pain visual analog scale (VAS for 10 days. As complementary data on the evaluation of pain, we recorded daily use of ketoprofen for pain relief. Results Pain after tonsillectomy assessed by VAS was significantly lower in the experimental group at days 0, 5, and 6 (p < 0.05. There were no differences in the use of ketoprofen between the groups. Conclusion Cooling of the oropharynx after tonsillectomy promotes clinically significant reduction in postoperative pain, without additional complications.

  6. Nursing students' assessment of pain and decision of triage for different ethnic groups: An experimental study.

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    Chan, Joanne C Y; Hamamura, Takeshi

    2015-08-01

    Pain management is a priority in nursing care but little is known about the factors that affect nursing students' assessment of pain expressed by patients of different ethnic backgrounds. This study examined undergraduate nursing students' assessment of pain and decision of triage when pain was expressed in different languages and their relation to students' empathy and social identity. Comparison between students with and without clinical experience was also carried out. This is a cross-sectional quantitative design. This study took place at a university in Hong Kong. 74 female undergraduate nursing students. Students listened to eight audio recordings in which an individual expressed pain in one of the two dialects of Chinese, either Cantonese or Putonghua. For each dialect, two recordings depicted mild pain and two depicted severe pain. After listening to each recording, students rated the pain level and indicated their decision of triage. Subsequently, students completed a questionnaire that measured their empathy and social identity and reported their demographics. The data were analyzed by descriptive statistics, correlational analyses, and t-tests. Severe pain described in Putonghua was rated as more intense than that described in Cantonese but it was not classified as more urgent. Students with clinical experience tended to perceive mild pain as less painful and less urgent than those without clinical experience. For mild pain described in Cantonese, students with clinical experience evaluated it as more urgent than those without such experience. The empathy level of students with and without clinical experience was comparable. Students with more empathy, especially those without clinical experience, reported heightened perceived intensity of severe pain described in Putonghua. Nurse educators should note that empathy, social identity, and clinical experience may alter students' pain assessment of patients from different ethnicities. Pain education needs to

  7. Pain worlds: towards the integration of a sociocultural perspective of pain in clinical physical therapy.

    Science.gov (United States)

    Killick, Lara; Davenport, Todd E

    2014-12-01

    The World Health Organization's International Classification of Functioning, Disability and Health (WHO-ICF) model has been advocated as a model of function to conceptualize physical therapist practice. Among its advances, the WHO-ICF model explicitly recognizes the existence of social factors that may influence patients' and clients' understanding of pain. However, understandings of the historical, social and cultural processes that shape the individual and collective experiences of pain and the therapeutic relationship remain limited. We call for a more intentional and sustained dialogue between clinical practice and sociology to help elucidate the nature, characteristics, complexities and clinical implications of one specific element of the WHO-ICF model, environmental factors. The purpose of this review is to advocate for the continued adoption of a sociological lens to help physical therapists better understand the broader networks of people, ideologies and practices in which people 'in pain' are enmeshed and the historical, geographical and cultural spaces in which they operate. In this review, we discuss existing empirical findings in sociology to introduce the concept of 'pain worlds', which can be applied by physical therapists to help characterize the sociocultural factors identified in the WHO-ICF model. Pain worlds is designed to complement the WHO-ICF model and assist in developing interdisciplinary research agendas that illuminate and examine the role, significance and clinical implications of sociocultural and environmental dimensions of pain. We conclude with a brief set of recommendations for the development of such translational research agendas and call for the integration of pain worlds in clinical practice. Copyright © 2014 John Wiley & Sons, Ltd.

  8. Effect of Experimental Hand Pain on Training-Induced Changes in Motor Performance and Corticospinal Excitability

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    Nicolas Mavromatis

    2017-02-01

    Full Text Available Pain influences plasticity within the sensorimotor system and the aim of this study was to assess the effect of pain on changes in motor performance and corticospinal excitability during training for a novel motor task. A total of 30 subjects were allocated to one of two groups (Pain, NoPain and performed ten training blocks of a visually-guided isometric pinch task. Each block consisted of 15 force sequences, and subjects modulated the force applied to a transducer in order to reach one of five target forces. Pain was induced by applying capsaicin cream to the thumb. Motor performance was assessed by a skill index that measured shifts in the speed–accuracy trade-off function. Neurophysiological measures were taken from the first dorsal interosseous using transcranial magnetic stimulation. Overall, the Pain group performed better throughout the training (p = 0.03, but both groups showed similar improvements across training blocks (p < 0.001, and there was no significant interaction. Corticospinal excitability in the NoPain group increased halfway through the training, but this was not observed in the Pain group (Time × Group interaction; p = 0.01. These results suggest that, even when pain does not negatively impact on the acquisition of a novel motor task, it can affect training-related changes in corticospinal excitability.

  9. Partners' Empathy Increases Pain Ratings: Effects of Perceived Empathy and Attachment Style on Pain Report and Display

    Science.gov (United States)

    Hurter, Sarah; Paloyelis, Yannis; de C. Williams, Amanda C.; Fotopoulou, Aikaterini

    2014-01-01

    Pain can be influenced by its social context. We aimed to examine under controlled experimental conditions how empathy from a partner and personal attachment style affect pain report, tolerance, and facial expressions of pain. Fifty-four participants, divided into secure, anxious, and avoidant attachment style groups, underwent a cold pressor task with their partners present. We manipulated how much empathy the participants perceived that their partners had for them. We observed a significant main effect of perceived empathy on pain report, with greater pain reported in the high perceived empathy condition. No such effects were found for pain tolerance or facial display. We also found a significant interaction of empathy with attachment style group, with the avoidant group reporting and displaying less pain than the secure and the anxious groups in the high perceived empathy condition. No such findings were observed in the low empathy condition. These results suggest that empathy from one's partner may influence pain report beyond behavioral reactions. In addition, the amount of pain report and expression that people show in high empathy conditions depends on their attachment style. Perspective Believing that one's partner feels high empathy for one's pain may lead individuals to rate the intensity of pain as higher. Individual differences in attachment style moderate this empathy effect. PMID:24953886

  10. Management of nerves during leg amputation--a neglected area in our understanding of the pathogenesis of phantom limb pain.

    Science.gov (United States)

    Rasmussen, S; Kehlet, H

    2007-09-01

    Chronic neuropathic pain after leg amputation is a significant problem, with a reported incidence during the first year as high as 70%. Intra-operative handling of the nerves during amputation has not been discussed in the literature on post-amputation pain and, in major textbooks, it is recommended that the ischial nerve be ligated, despite the fact that the experimental literature uses nerve ligations to produce neuropathic pain. The purpose of this study was to investigate the clinical practice of nerve handling during leg amputation. Trainees with at least 2 years of practice received a questionnaire regarding handling of the nerves during leg amputation; 128 of 149 questionnaires sent (86%) were returned. Ligation of the nerves was used by 31% of surgeons. There is no consistency in the management of the large nerves during lower leg amputation. The recommendations in major textbooks may not be appropriate when compared with the experimental literature on nerve ligature models to produce neuropathic pain. Future studies on post-amputation pain should consider intra-operative nerve management.

  11. The Effectiveness of Self Management Program on Pain, Fatigue, Depression, Anxiety, and Stress in Sickle Cell Patients: A Quasi-Experimental Study

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    Ahmadi

    2015-10-01

    Full Text Available Background Patients with sickle cell disease, who must manage serious and unpredictable complications related to their disease, particularly chronic pain, suffer from numerous psychosocial problems such as depression, anxiety, stress, and disruption of interpersonal relationships; these problems often lead to fatigue and poor quality of life. Objectives This study aimed to determine the effectiveness of self-management programs targeting pain, fatigue, depression, anxiety, and stress in sickle cell patients. Patients and Methods This was a quasi-experimental study; participants were 53 patients with sickle cell disease who were referred to the Thalassemia Clinic of Ahvaz Shafa Hospital. Participants were recruited by census in 2013. Participants received a self-management program that was implemented in five sessions over 12 weeks. Levels of fatigue, depression, anxiety, and stress were assessed before and 24 weeks after the intervention; pain was assessed during the intervention and at a 24 week post-intervention follow-up using the fatigue severity scale (FSS, DASS21, and a pain record. Descriptive statistics, Fisher’s exact test, Chi-square, independent t-tests, paired t-tests, repeated measures tests and correlations were used to analyze the data. Results Scores for fatigue, anxiety, depression, and stress after the intervention were significantly decreased compared to before the intervention (P < 0.001. Repeated measures testing showed that mean scores for frequency and duration of pain decreased significantly during the 12 weeks of intervention, as well as during the 24 weeks of follow-up (P < 0.001. Conclusions The results suggest the effectiveness of self-management programs on the reduction of pain, fatigue, anxiety, depression, and stress in sickle cell patients. Therefore, self-management programs are advisable in order to empower patients and assist their management of health-related problems.

  12. Inviting pain? Pain, dualism and embodiment in narratives of self-injury.

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    Chandler, Amy

    2013-06-01

    The role of pain in the practice of self-injury is not straightforward. Existing accounts suggest that self-injury does not cause 'physical' pain, however self-injury is also said to alleviate 'emotional' pain by inflicting 'physical' pain. This article explores these tensions using sociological theories regarding the socio-cultural and subjective nature of pain. Analysis derives from in-depth, life-story interviews carried out in the UK with people who had self-injured. Findings contribute to on-going debates within social science regarding the nature of pain. Participants' narratives about pain and self-injury both drew on and challenged dualistic models of embodiment. I suggest that self-injury offers a unique case on which to extend existing theoretical work, which has tended to focus on pain as an unwanted and uninvited entity. In contrast, accounts of self-injury can feature pain as a central aspect of the practice, voluntarily invited into lived experience. © 2013 The Author. Sociology of Health & Illness © 2013 Foundation for the Sociology of Health & Illness/John Wiley & Sons Ltd.

  13. The Effect of Listening to Music on Postoperative Pain in Adult Orthopedic Patients.

    Science.gov (United States)

    Schneider, Melissa A

    2018-03-01

    Pain is a common occurrence after orthopedic surgery. Patients need additional resources to manage their pain. The purpose of this study was to determine if listening to music has a positive effect on pain scores and satisfaction in the postoperative adult orthopedic patient. There are limited studies demonstrating statistically significant decreases in postoperative pain in this group. A secondary purpose was to expose nurses on a standard medical-surgical unit to an intervention, supported by the holistic nursing model that they could use in their care. This study was a descriptive, comparative, quasi-experimental design. Patients listened to prerecorded music on individual CD players and recorded pre-post pain scores with the intervention. A satisfactory survey was completed at discharge. Results demonstrated a statistically significant reduction in patients' pain scores after listening to music. Length of listening time had no effect. Patients expressed overall satisfaction, and 100% of participants would recommend this intervention to others. Listening to music is beneficial as an adjunct to pain medication and contributes to increased patient satisfaction. It is hoped that the information gained from this study will lead to an enhancement in the standard of care for postoperative patients.

  14. Effect of verbal persuasion on self-efficacy for pain-related diagnostic sensory testing in individuals with chronic neck pain and healthy controls - a randomized, controlled trial.

    Science.gov (United States)

    Söderlund, Anne; Sterling, Michele

    2016-01-01

    The aim of this study was to investigate the differences in cold pain threshold (CTh), pressure pain threshold (PPT), cold pain tolerance (CPTo) tests, and the level of self-efficacy when self-efficacy for diagnostic sensory testing was manipulated by verbal persuasion before a testing situation in persons with neck pain and in healthy controls. A randomized experimental design was used. Twenty-one healthy volunteers and 22 individuals with either traumatic or nontraumatic chronic neck pain were recruited to participate in the study. The intervention consisted of two experimental verbal persuasion conditions: Increase self-efficacy and Decrease self-efficacy. The PPT was measured using a pressure algometer, the CTh was measured using a thermo test system, and CPTo was measured by submerging the participant's hand in ice water up to the elbow joint. On three occasions, the participants reported their self-efficacy level in performing the sensory tests. In the chronic neck pain group, there were no differences in pain threshold or tolerance. There was a difference in the self-efficacy level after verbal persuasion between the experimental conditions. In the healthy control group, the CThs increased following the condition that aimed to increase self-efficacy. No other differences were observed in the healthy controls. A short verbal persuasion in the form of manipulative instructions seems to have a marginal effect on the individual's self-efficacy levels in the chronic neck pain group and a slight influence on the results of sensory testing in healthy controls.

  15. Antiallodynic Effects of Bee Venom in an Animal Model of Complex Regional Pain Syndrome Type 1 (CRPS-I).

    Science.gov (United States)

    Lee, Sung Hyun; Lee, Jae Min; Kim, Yun Hong; Choi, Jung Hyun; Jeon, Seung Hwan; Kim, Dong Kyu; Jeong, Hyeon Do; Lee, You Jung; Park, Hue Jung

    2017-09-15

    Neuropathic pain in a chronic post-ischaemic pain (CPIP) model mimics the symptoms of complex regional pain syndrome type I (CRPS I). The administration of bee venom (BV) has been utilized in Eastern medicine to treat chronic inflammatory diseases accompanying pain. However, the analgesic effect of BV in a CPIP model remains unknown. The application of a tight-fitting O-ring around the left ankle for a period of 3 h generated CPIP in C57/Bl6 male adult mice. BV (1 mg/kg ; 1, 2, and 3 times) was administered into the SC layer of the hind paw, and the antiallodynic effects were investigated using the von Frey test and by measuring the expression of neurokinin type 1 (NK-1) receptors in dorsal root ganglia (DRG). The administration of BV dose-dependently reduced the pain withdrawal threshold to mechanical stimuli compared with the pre-administration value and with that of the control group. After the development of the CPIP model, the expression of NK-1 receptors in DRG increased and then decreased following the administration of BV. SC administration of BV results in the attenuation of allodynia in a mouse model of CPIP. The antiallodynic effect was objectively proven through a reduction in the increased expression of NK-1 receptors in DRG.

  16. Autonomic nervous system function in patients with functional abdominal pain. An experimental study

    DEFF Research Database (Denmark)

    Jørgensen, L S; Christiansen, P; Raundahl, U

    1993-01-01

    Functional abdominal pain--that is, pain without demonstrable organic abnormalities--has often been associated with psychologic stress. The aim of the present study was to investigate whether sympathetic nervous system response to laboratory stress and basal parasympathetic neural activity were...

  17. New perspectives in EEG/MEG brain mapping and PET/fMRI neuroimaging of human pain.

    Science.gov (United States)

    Chen, A C

    2001-10-01

    With the maturation of EEG/MEG brain mapping and PET/fMRI neuroimaging in the 1990s, greater understanding of pain processing in the brain now elucidates and may even challenge the classical theory of pain mechanisms. This review scans across the cultural diversity of pain expression and modulation in man. It outlines the difficulties in defining and studying human pain. It then focuses on methods of studying the brain in experimental and clinical pain, the cohesive results of brain mapping and neuroimaging of noxious perception, the implication of pain research in understanding human consciousness and the relevance to clinical care as well as to the basic science of human psychophysiology. Non-invasive brain studies in man start to unveil the age-old puzzles of pain-illusion, hypnosis and placebo in pain modulation. The neurophysiological and neurohemodynamic brain measures of experimental pain can now largely satisfy the psychophysiologist's dream, unimaginable only a few years ago, of modelling the body-brain, brain-mind, mind-matter duality in an inter-linking 3-P triad: physics (stimulus energy); physiology (brain activities); and psyche (perception). For neuropsychophysiology greater challenges lie ahead: (a) how to integrate a cohesive theory of human pain in the brain; (b) what levels of analyses are necessary and sufficient; (c) what constitutes the structural organisation of the pain matrix; (d) what are the modes of processing among and across the sites of these structures; and (e) how can neural computation of these processes in the brain be carried out? We may envision that modular identification and delineation of the arousal-attention, emotion-motivation and perception-cognition neural networks of pain processing in the brain will also lead to deeper understanding of the human mind. Two foreseeable impacts on clinical sciences and basic theories from brain mapping/neuroimaging are the plausible central origin in persistent pain and integration of

  18. Exploring the associations shared by mood, pain-related attention and pain outcomes related to sleep disturbance in a chronic pain sample.

    Science.gov (United States)

    Harrison, Lee; Wilson, Sue; Heron, Jon; Stannard, Catherine; Munafò, Marcus R

    2016-05-01

    Sleep disturbance in chronic pain is common, occurring in two-thirds of patients. There is a complex relationship between chronic pain and sleep; pain can disrupt sleep and poor sleep can exaggerate pain intensity. This may have an impact on both depressive symptoms and attention to pain. This study aims to evaluate the relationship between chronic pain and sleep, and the role of mood and attention. Chronic pain patients, recruited from a secondary care outpatient clinic, completed self-report measures of pain, sleep, depressive symptoms and attention to pain. Hierarchical regression and structural equation modelling were used to explore the relationships between these measures. Participants (n = 221) were aged between 20 and 84 (mean = 52) years. The majority of participants were found to be 'poor sleepers' (86%) with increased pain severity, depressive symptoms and attention to pain. Both analytical approaches indicated that sleep disturbance is indirectly associated with increased pain severity Instead the relationship shared by sleep disturbance and pain severity was further associated with depressive symptoms and attention to pain. Our results indicate that sleep disturbance may contribute to clinical pain severity indirectly though changes in mood and attention. Prospective studies exploring lagged associations between these constructs could have critical information relevant to the treatment of chronic pain.

  19. How Repeated Time To Event (RTTE) modelling of opioid requests after surgery may improve future post-operative pain management

    DEFF Research Database (Denmark)

    Juul, Rasmus Vestergaard; Rasmussen, Sten; Kreilgaard, Mads

    at Orthopaedic Department, Aalborg University Hospital, Denmark during the period May-Dec 2012. Morphine administration times (estimated precision: ±5mins), formulations and doses were extracted from medical journals in the hospitalization period or until 96 hours after surgery. RTTE modelling was performed......Title: How Repeated Time To Event (RTTE) modelling of opioid requests after surgery may improve future post-operative pain management Author: Rasmus Vestergaard Juul (1) Sten Rasmussen (2) Mads Kreilgaard (1) Ulrika S. H. Simonsson (3) Lona Louring Christrup (1) Trine Meldgaard Lund (1) Institution...... of surgery specific, drug concentration related, population specific and/or time-varying covariates of opioid requests and pain events. Conclusions: A framework has been developed based on RTTE modelling that may help improve future pain management by 1) Identification of surgery specific patterns in pain...

  20. Evoked potentials after painful cutaneous electrical stimulation depict pain relief during a conditioned pain modulation.

    Science.gov (United States)

    Höffken, Oliver; Özgül, Özüm S; Enax-Krumova, Elena K; Tegenthoff, Martin; Maier, Christoph

    2017-08-29

    Conditioned pain modulation (CPM) evaluates the pain modulating effect of a noxious conditioning stimulus (CS) on another noxious test stimulus (TS), mostly based solely on subjective pain ratings. We used painful cutaneous electrical stimulation (PCES) to induce TS in a novel CPM-model. Additionally, to evaluate a more objective parameter, we recorded the corresponding changes of cortical evoked potentials (PCES-EP). We examined the CPM-effect in 17 healthy subjects in a randomized controlled cross-over design during immersion of the non-dominant hand into 10 °C or 24 °C cold water (CS). Using three custom-built concentric surface electrodes, electrical stimuli were applied on the dominant hand, inducing pain of 40-60 on NRS 0-100 (TS). At baseline, during and after CS we assessed the electrically induced pain intensity and electrically evoked potentials recorded over the central electrode (Cz). Only in the 10 °C-condition, both pain (52.6 ± 4.4 (baseline) vs. 30.3 ± 12.5 (during CS)) and amplitudes of PCES-EP (42.1 ± 13.4 μV (baseline) vs. 28.7 ± 10.5 μV (during CS)) attenuated during CS and recovered there after (all p pain ratings during electrical stimulation and amplitudes of PCES-EP correlated significantly with each other (r = 0.5) and with CS pain intensity (r = 0.5). PCES-EPs are a quantitative measure of pain relief, as changes in the electrophysiological response are paralleled by a consistent decrease in subjective pain ratings. This novel CPM paradigm is a feasible method, which could help to evaluate the function of the endogenous pain modulation processes. German Clinical Trials Register DRKS-ID: DRKS00012779 , retrospectively registered on 24 July 2017.

  1. Nursing patients with acute chest pain: practice guided by the Prince Edward Island conceptual model for nursing.

    Science.gov (United States)

    Blanchard, Janelle F; Murnaghan, Donna A

    2010-01-01

    Current research suggests that pain is a relatively common phenomenon with 60-90% of patients presenting to emergency departments reporting pain (e.g., chest pain, trauma, extremity fractures and migraine headache) that require treatment [Hogan, S.L., 2005. Patient satisfaction with pain management in the emergency department. Advanced Emergency Nursing Journal 27(4), 284-294]. This article explores the use of conceptual theoretical empirical (C-T-E) framework to guide a senior nursing student in a case study of patient with chest pain. The Middle Range Theory of Pain described by Good [Good, M., 1998. A middle-range theory of acute pain management: use in research. Nursing Outlook 46(3), 120-124] and Melzack's [Melzack, R., 1987. The short-form McGill pain questionnaire. Pain, 30, 191-197] short form McGill pain questionnaire were applied along with the Prince Edward Island conceptual model (PEICM) for nursing. Results indicate that the nursing student increased her ability to work in partnership, assess relevant and specific information, and identify a number of strategies to help the patient achieve pain control by using a complement of pharmacological and non-pharmacological interventions. Moreover, the C-T-E approach provided an organized and systematic theoretical approach for the nursing student to assist a patient in pain control.

  2. Pain management for older persons living in nursing homes: a pilot study.

    Science.gov (United States)

    Tse, Mimi M Y; Ho, Suki S K

    2013-06-01

    Because the prevalence of chronic pain among the elderly in nursing homes is high and decreases their quality of life, effective nonpharmacologic pain management should be promoted. The purpose of this quasiexperimental pretest and posttest control design was to enhance pain management in nursing homes via an integrated pain management program (IPMP) for staff and residents. Nursing staff and residents from the experimental nursing home were invited to join the 8-week IPMP, whereas staff and residents from the control nursing home did not receive the IPMP. Baseline data were collected from nursing staff and residents in both groups before and after the IPMP. The IPMP consisted of eight lectures on pain assessment, drug knowledge,and nondrug strategies for the nursing staff, and 8 weeks of activities, including gardening therapy and physiotherapy exercise, for the residents. There were 48 and 42 older people in the experimental and control groups, respectively. No significant differences were found in their educational level, sleep quality, bowel habits, past and present health conditions, pain conditions and psychologic well-being parameters (p > .05) at baseline. After the IPMP, the experimental nursing staff showed a significant improvement in their knowledge of and attitudes to pain management (p pain scores and used more nondrug strategies for pain relief compared with the control group (p nursing staff, as well as reducing pain conditions and enhancing psychologic well-being for older persons in nursing homes. Copyright © 2013 American Society for Pain Management Nursing. Published by Elsevier Inc. All rights reserved.

  3. Pain empathy in schizophrenia: an fMRI study.

    Science.gov (United States)

    Horan, William P; Jimenez, Amy M; Lee, Junghee; Wynn, Jonathan K; Eisenberger, Naomi I; Green, Michael F

    2016-05-01

    Although it has been proposed that schizophrenia is characterized by impaired empathy, several recent studies found intact neural responses on tasks measuring the affective subdomain of empathy. This study further examined affective empathy in 21 schizophrenia outpatients and 21 healthy controls using a validated pain empathy paradigm with two components: (i) observing videos of people described as medical patients who were receiving a painful sound stimulation treatment; (ii) listening to the painful sounds (to create regions of interest). The observing videos component incorporated experimental manipulations of perspective taking (instructions to imagine 'Self' vs 'Other' experiencing pain) and cognitive appraisal (information about whether treatment was 'Effective' vs 'Not Effective'). When considering activation across experimental conditions, both groups showed similar dorsal anterior cingulate cortex (dACC) and anterior insula (AI) activation while merely observing others in pain. However, there were group differences associated with perspective taking: controls showed relatively greater dACC and AI activation for the Self vs Other contrast whereas patients showed relatively greater activation in these and additional regions for the Other vs Self contrast. Although patients demonstrated grossly intact neural activity while observing others in pain, they showed more subtle abnormalities when required to toggle between imagining themselves vs others experiencing pain. © The Author (2016). Published by Oxford University Press. For Permissions, please email: journals.permissions@oup.com.

  4. Synergistic interactions between paracetamol and oxcarbazepine in somatic and visceral pain models in rodents.

    Science.gov (United States)

    Tomić, Maja A; Vucković, Sonja M; Stepanović-Petrović, Radica M; Ugresić, Nenad D; Prostran, Milica S; Bosković, Bogdan

    2010-04-01

    Combination therapy is a valid approach in pain treatment, in which a reduction of doses could reduce side effects and still achieve optimal analgesia. We examined the effects of coadministered paracetamol, a widely used non-opioid analgesic, and oxcarbazepine, a relatively novel anticonvulsant with analgesic properties, in a rat model of paw inflammatory hyperalgesia and in a mice model of visceral pain and determined the type of interaction between components. The effects of paracetamol, oxcarbazepine, and their combinations were examined in carrageenan-induced (0.1 mL, 1%) paw inflammatory hyperalgesia in rats and in an acetic acid-induced (10 mg/kg, 0.75%) writhing test in mice. In both models, drugs were coadministered in fixed-dose fractions of the 50% effective dose (ED(50)), and type of interaction was determined by isobolographic analysis. Paracetamol (50-200 mg/kg peroral), oxcarbazepine (40-160 mg/kg peroral), and their combination (1/8, 1/4, 1/3, and 1/2 of a single drug ED(50)) produced a significant, dose-dependent antihyperalgesia in carrageenan-injected rats. In the writhing test in mice, paracetamol (60-180 mg/kg peroral), oxcarbazepine (20-80 mg/kg peroral), and their combination (1/16, 1/8, 1/4, and 1/2 of a single drug ED(50)) significantly and dose dependently reduced the number of writhes. In both models, isobolographic analysis revealed a significant synergistic interaction between paracetamol and oxcarbazepine, with a >4-fold reduction of doses of both drugs in combination, compared with single drugs ED(50). The synergistic interaction between paracetamol and oxcarbazepine provides new information about combination pain treatment and should be explored further in patients, especially with somatic and/or visceral pain.

  5. A multilevel structural equation modeling analysis of vulnerabilities and resilience resources influencing affective adaptation to chronic pain.

    Science.gov (United States)

    Sturgeon, John A; Zautra, Alex J; Arewasikporn, Anne

    2014-02-01

    The processes of individual adaptation to chronic pain are complex and occur across multiple domains. We examined the social, cognitive, and affective context of daily pain adaptation in individuals with fibromyalgia and osteoarthritis. By using a sample of 260 women with fibromyalgia or osteoarthritis, we examined the contributions of pain catastrophizing, negative interpersonal events, and positive interpersonal events to daily negative and positive affect across 30days of daily diary data. Individual differences and daily fluctuations in predictor variables were estimated simultaneously by utilizing multilevel structural equation modeling techniques. The relationships between pain and negative and positive affect were mediated by stable and day-to-day levels of pain catastrophizing as well as day-to-day positive interpersonal events, but not negative interpersonal events. There were significant and independent contributions of pain catastrophizing and positive interpersonal events to adaptation to pain and pain-related affective dysregulation. These effects occur both between persons and within a person's everyday life. Copyright © 2013 International Association for the Study of Pain. Published by Elsevier B.V. All rights reserved.

  6. Randomized Trial of Modified Stretching Exercise Program for Menstrual Low Back Pain.

    Science.gov (United States)

    Chen, Huei-Mein; Hu, Hsou-Mei

    2018-03-01

    This study aimed to examine the effectiveness of a modified stretching exercise program on young women with menstrual low back pain. Overall, 127 young women were randomly assigned to the experimental ( n = 63) and control ( n = 64) groups. The experimental group followed the modified stretching exercise program, whereas the control group performed their usual activities. At 1, 4, 8, and 12 months, the experimental group had significantly lower scores on the visual analog scale for pain (95% confidence interval [CI] = [0.73, 1.96]; p < .05) and the Oswestry Low Back Pain Disability Questionnaire than the control group (95% CI = [0.68, 2.03]; p < .001). At 12 months, the experimental group showed significantly higher exercise self-efficacy than the control group (95% CI = [-6.87, 0.62]; p = .003). These findings can be used to enhance self-care capabilities by using the modified stretching exercise program for young women with menstrual low back pain.

  7. Gait changes in patients with knee osteoarthritis are replicated by experimental knee pain

    DEFF Research Database (Denmark)

    Henriksen, Marius; Graven-Nielsen, Thomas; Aaboe, Jens

    2010-01-01

    Medial knee osteoarthritis (OA) is characterized by pain and associated with abnormal knee moments during walking. The relationship between knee OA pain and gait changes remains to be clarified, and a better understanding of this link could advance the treatment and prevention of disease...

  8. Chronic Low Back Pain: Toward an Integrated Psychosocial Assessment Model.

    Science.gov (United States)

    Strong, Jenny; And Others

    1994-01-01

    Integrated six dimensions of chronic low back pain (pain intensity, functional disability, attitudes toward pain, pain coping strategies, depression, illness behavior) to provide multidimensional patient profile. Data from 100 patients revealed presence of three distinct patient groups: patients who were in control, patients who were depressed and…

  9. Chronic Pain Treatment: The Influence of Tricyclic Antidepressants on Serotonin Release and Uptake in Mast Cells

    Directory of Open Access Journals (Sweden)

    Ilonka Ferjan

    2013-01-01

    Full Text Available The involvement of serotonin (5-HT in chronic pain mechanisms is established. 5-HT inhibits central painful stimuli, but recent data suggests that 5-HT could also enhance pain stimulus from the periphery, where mast cells play an important role. We aimed in our study to clarify the influence of selected tricyclic antidepressants (TCAs on mast cell function: secretion, uptake, and reuptake of 5-HT, that could interfere with 5-HT levels and in this way contribute to the generation of pain. As an experimental model, we used isolated rat peritoneal mast cells and incubated them with selected TCAs (clomipramine, amitriptyline, doxepin, and imipramine under different experimental conditions. 5-HT release, uptake, and reuptake were determined spectrofluorometrically. We showed that TCAs were able to inhibit 5-HT secretion from mast cells, as well as uptake of exogenous 5-HT and reuptake of secreted 5-HT back into mast cells. The effects of TCAs were concentration dependent; higher concentrations of TCAs inhibited the secretion of 5-HT induced by compound 48/80, whereas lower concentrations of TCAs inhibited 5-HT uptake. The most effective TCA was halogenated clomipramine. As TCAs are well introduced in chronic pain treatment, the insight into mechanisms of action is important for an understanding of their effect in various pain conditions.

  10. Influence of Catastrophizing and Personality Traits on Recalled Ratings of Acute Pain Experience in Healthy Young Adults.

    Science.gov (United States)

    Pallegama, Ranjith Wasantha; Ariyasinghe, Sajjiv; Perera, Eranthi Dinoka; Treede, Rolf-Detlef

    2017-01-01

    To investigate whether pain catastrophizing and personality traits bias recalled ratings of acute pain in an experimental tonic pain model. Fifty-six undergraduates (14 males) recruited from the University of Peradeniya (mean age 21.7 ± 0.8 SD years). Participants completed the Pain Catastrophizing Scale and the Eysenck Personality Questionnaire. They were subjected to two cold pressor tests (dominant and non-dominant hands) and pain threshold, maximum pain intensity, and pain tolerance were recorded. One-week later, the maximum pain intensities of both hands were recalled and percentage distortions in recalling were calculated. Based on a 180 s cutoff, two participants were considered pain-insensitive during the test and were excluded from the analysis. The maximum pain intensity was recalled with a moderate accuracy (Intraclass Correlation Coefficients = 0.68 for dominant and 0.59 for non-dominant hands). Hierarchical multiple regression analyses revealed that maximum pain intensity ( P  personality traits only neuroticism exhibited a weak positive association with the recalled ratings. © 2016 American Academy of Pain Medicine. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com

  11. PEMFC modeling and experimental validation

    Energy Technology Data Exchange (ETDEWEB)

    Vargas, J.V.C. [Federal University of Parana (UFPR), Curitiba, PR (Brazil). Dept. of Mechanical Engineering], E-mail: jvargas@demec.ufpr.br; Ordonez, J.C.; Martins, L.S. [Florida State University, Tallahassee, FL (United States). Center for Advanced Power Systems], Emails: ordonez@caps.fsu.edu, martins@caps.fsu.edu

    2009-07-01

    In this paper, a simplified and comprehensive PEMFC mathematical model introduced in previous studies is experimentally validated. Numerical results are obtained for an existing set of commercial unit PEM fuel cells. The model accounts for pressure drops in the gas channels, and for temperature gradients with respect to space in the flow direction, that are investigated by direct infrared imaging, showing that even at low current operation such gradients are present in fuel cell operation, and therefore should be considered by a PEMFC model, since large coolant flow rates are limited due to induced high pressure drops in the cooling channels. The computed polarization and power curves are directly compared to the experimentally measured ones with good qualitative and quantitative agreement. The combination of accuracy and low computational time allow for the future utilization of the model as a reliable tool for PEMFC simulation, control, design and optimization purposes. (author)

  12. Prediction of postoperative pain by preoperative pain response to heat stimulation in total knee arthroplasty.

    Science.gov (United States)

    Lunn, Troels H; Gaarn-Larsen, Lissi; Kehlet, Henrik

    2013-09-01

    It has been estimated that up to 54% of the variance in postoperative pain experience may be predicted with preoperative pain responses to experimental stimuli, with suprathreshold heat pain as the most consistent test modality. This study aimed to explore whether 2 heat test paradigms could predict postoperative pain after total knee arthroplasty (TKA). Patients scheduled for elective, unilateral, primary TKA under spinal anesthesia were consecutively included in this prospective, observational study. Perioperative analgesia was standardized for all patients. Outcomes were postoperative pain during walk: from 6 to 24 hours (primary), from postoperative day (POD) 1 to 7 (secondary), and from POD 14 to 30 (tertiary). Two preoperative tonic heat stimuli with 47°C were used; short (5 seconds) and long (7 minutes) stimulation upon which patients rated their pain response on an electronic visual analog scale. Multivariate stepwise linear and logistic regressions analyses were carried out, including 8 potential preoperative explanatory variables (among these anxiety, depression, preoperative pain, and pain catastrophizing) to assess pain response to preoperative heat pain stimulation as an independent predictor for postoperative pain. A total of 100 patients were included, and 3 were later excluded. A weak correlation [rho (95% confidence interval); P value] was observed between pain from POD 1 to 7 and pain response to short [rho=0.25(0.04 to 0.44); P=.02] and to long [rho=0.27 (0.07 to 0.46); P=.01] heat pain stimulation. However, these positive correlations were not supported by the linear and logistic regression analyses, in which only anxiety, preoperative pain, and pain catastrophizing were significant explanatory variables (but with low R-squares; 0.05 to 0.08). Pain responses to 2 types of preoperative heat stimuli were not independent clinically relevant predictors for postoperative pain after TKA. Copyright © 2013 International Association for the Study of

  13. Optimism Moderates the Influence of Pain Catastrophizing on Shoulder Pain Outcome: A Longitudinal Analysis.

    Science.gov (United States)

    Coronado, Rogelio A; Simon, Corey B; Lentz, Trevor A; Gay, Charles W; Mackie, Lauren N; George, Steven Z

    2017-01-01

    Study Design Secondary analysis of prospectively collected data. Background An abundance of evidence has highlighted the influence of pain catastrophizing and fear avoidance on clinical outcomes. Less is known about the interaction of positive psychological resources with these pain-associated distress factors. Objective To assess whether optimism moderates the influence of pain catastrophizing and fear avoidance on 3-month clinical outcomes in patients with shoulder pain. Methods Data from 63 individuals with shoulder pain (mean ± SD age, 38.8 ± 14.9 years; 30 female) were examined. Demographic, psychological, and clinical characteristics were obtained at baseline. Validated measures were used to assess optimism (Life Orientation Test-Revised), pain catastrophizing (Pain Catastrophizing Scale), fear avoidance (Fear-Avoidance Beliefs Questionnaire physical activity subscale), shoulder pain intensity (Brief Pain Inventory), and shoulder function (Pennsylvania Shoulder Score function subscale). Shoulder pain and function were reassessed at 3 months. Regression models assessed the influence of (1) pain catastrophizing and optimism and (2) fear avoidance and optimism. The final multivariable models controlled for factors of age, sex, education, and baseline scores, and included 3-month pain intensity and function as separate dependent variables. Results Shoulder pain (mean difference, -1.6; 95% confidence interval [CI]: -2.1, -1.2) and function (mean difference, 2.4; 95% CI: 0.3, 4.4) improved over 3 months. In multivariable analyses, there was an interaction between pain catastrophizing and optimism (β = 0.19; 95% CI: 0.02, 0.35) for predicting 3-month shoulder function (F = 16.8, R 2 = 0.69, Poptimism lessened the influence of pain catastrophizing on function. There was no evidence of significant moderation of fear-avoidance beliefs for 3-month shoulder pain (P = .090) or function (P = .092). Conclusion Optimism decreased the negative influence of pain

  14. An Evolutionary Perspective on Pain Communication

    Directory of Open Access Journals (Sweden)

    Leander Steinkopf

    2016-06-01

    Full Text Available Pain serves as a signal to elicit care from others. In turn, displaying pain might be attractive because of the benefits it might bring. Additionally, displaying pain is easy, because helpers distinguish poorly between genuine pain and faked pain. Hence, helpers face the problem of distinguishing true sufferers from free riders, while sufferers face the problem of communicating need convincingly. This article will propose solutions to these adaptive problems. Based on theoretical arguments and on empirical insights from lie detection research, it will be argued that the credibility of pain signals cannot be found in features of the signal itself, but in its context. Namely, pain is obviously credible when the context features unforgeable cues, such as an open wound or the enlarged abdomen of a pregnant woman, but also external cues such as the ice water in cold pressor tasks. In absence of such cues, pain can become credible through costly consequences, such as refraining from rewarding behaviors for a significant period. However, these adaptive mechanisms for communicating need may not be shaped for modern circumstances such as experimental settings and therapeutic encounters.

  15. The analgesic effect of orexin-A in a murine model of chemotherapy-induced neuropathic pain.

    Science.gov (United States)

    Toyama, Satoshi; Shimoyama, Naohito; Shimoyama, Megumi

    2017-02-01

    Orexins are neuropeptides that are localized to neurons in the lateral and dorsal hypothalamus but its receptors are distributed to many different regions of the central nervous system. Orexins are implicated in a variety of physiological functions including sleep regulation, energy homeostats, and stress reactions. Furthermore, orexins administered exogenously have been shown to have analgesic effects in animal models. A type of intractable pain in patients is pain due to chemotherapy-induced peripheral neuropathy (CIPN). Several chemotherapeutic agents used for the treatment of malignant diseases induce dose-limiting neuropathic pain that compromises patients' quality of life. Here, we examined the analgesic effect of orexin-A in a murine model of CIPN, and compared it with the effect of duloxetine, the only drug recommended for the treatment of CIPN pain in patients. CIPN was induced in male BALB/c mice by repeated intraperitoneal injection of oxaliplatin, a platinum chemotherapeutic agent used for the treatment of advanced colorectal cancer. Neuropathic mechanical allodynia was assessed by the von Frey test, and the effect on acute thermal pain was assessed by the tail flick test. Intracerebroventricularly administered orexin-A dose-dependently attenuated oxaliplatin-induced mechanical allodynia and increased tail flick latencies. Oxaliplatin-induced mechanical allodynia was completely reversed by orexin-A at a low dose that did not increase tail flick latency. Duloxetine only partially reversed mechanical allodynia and had no effect on tail flick latency. The analgesic effect of orexin-A on oxaliplatin-induced mechanical allodynia was completely antagonized by prior intraperitoneal injection of SB-408124 (orexin type-1 receptor antagonist), but not by prior intraperitoneal injection of TCS-OX2-29 (orexin type-2 receptor antagonist). Our findings suggest that orexin-A is more potent than duloxetine in relieving pain CIPN pain and its analgesic effect is

  16. Pain Catastrophizing and Anxiety are Associated With Heat Pain Perception in a Community Sample of Adults With Chronic Pain.

    Science.gov (United States)

    Terry, Marisa J; Moeschler, Susan M; Hoelzer, Bryan C; Hooten, W Michael

    2016-10-01

    The principle aim of this study was to investigate the associations between heat pain (HP) perception, pain catastrophizing, and pain-related anxiety in a heterogenous cohort of community-dwelling adults with chronic pain admitted to a 3-week outpatient pain rehabilitation program. All adults consecutively admitted to an outpatient pain rehabilitation program from July 2009 through January 2011 were eligible for study recruitment (n=574). Upon admission, patients completed the Pain Catastrophizing Scale (PCS), the short version of the Pain Anxiety Symptoms Scale (PASS-20), and HP perception was assessed using a standardized quantitative sensory testing (QST) method of levels. Greater PCS scores were significantly correlated with lower standardized values of HP threshold (HP 0.5) (P=0.006) and tolerance (HP 5) (P=0.003). In a multiple variable model adjusted for demographic and clinical factors known to influence HP perception, every 10-point increase in the PCS was associated with a -0.124 point change in HP 0.5 (P=0.014) and a -0.142 change in HP 5 (P=0.014) indicating that participants with higher PCS scores had lower HP thresholds and tolerances, respectively. Similarly, greater PASS-20 scores significantly correlated with lower standardized values of HP 0.5 and HP 5. In a multiple variable model, every 10-point increase in the PASS-20 was associated with a -0.084 point change in HP 0.5 (P=0.005) and a -0.116 point change in HP 5 (P=0.001) indicating that participants with higher PASS-20 scores had lower HP thresholds and tolerances, respectively. The findings of this study extend the use of a standardized method for assessing HP in a heterogenous sample of adults with chronic pain. Although pain catastrophizing shares significant variance with pain-related anxiety, our findings suggest that either measure would be appropriate for use in future studies that incorporate the QST method of levels.

  17. Effect of verbal persuasion on self-efficacy for pain-related diagnostic sensory testing in individuals with chronic neck pain and healthy controls – a randomized, controlled trial

    Directory of Open Access Journals (Sweden)

    Söderlund A

    2016-03-01

    Full Text Available Anne Söderlund,1 Michele Sterling,2 1Physiotherapy, School of Health, Care and Social Welfare, Mälardalen University, Västerås, Sweden; 2Centre for National Research on Disability and Rehabilitation Medicine (CONROD, Menzies Health Institute Queensland, Griffith University, Parklands, Australia Abstract: The aim of this study was to investigate the differences in cold pain threshold (CTh, pressure pain threshold (PPT, cold pain tolerance (CPTo tests, and the level of self-efficacy when self-efficacy for diagnostic sensory testing was manipulated by verbal persuasion before a testing situation in persons with neck pain and in healthy controls. A randomized experimental design was used. Twenty-one healthy volunteers and 22 individuals with either traumatic or nontraumatic chronic neck pain were recruited to participate in the study. The intervention consisted of two experimental verbal persuasion conditions: Increase self-efficacy and Decrease self-efficacy. The PPT was measured using a pressure algometer, the CTh was measured using a thermo test system, and CPTo was measured by submerging the participant's hand in ice water up to the elbow joint. On three occasions, the participants reported their self-efficacy level in performing the sensory tests. In the chronic neck pain group, there were no differences in pain threshold or tolerance. There was a difference in the self-efficacy level after verbal persuasion between the experimental conditions. In the healthy control group, the CThs increased following the condition that aimed to increase self-efficacy. No other differences were observed in the healthy controls. A short verbal persuasion in the form of manipulative instructions seems to have a marginal effect on the individual's self-efficacy levels in the chronic neck pain group and a slight influence on the results of sensory testing in healthy controls. Keywords: pressure pain threshold, cold pain threshold, cold pain tolerance, self

  18. Experimental pain in human temporal muscle induced by hypertonic saline, potassium and acidity

    DEFF Research Database (Denmark)

    Jensen, K; Norup, M

    1992-01-01

    chloride (n = 12) induced significantly more pain than isotonic saline (ANOVA, p less than 0.0001). Compared to control injections, hypertonic saline and potassium chloride induced a significant reduction in pressure-pain threshold (ANOVA, p less than 0.0001 and p less than 0.05). Forty-eight percent...

  19. Effects of validating communication on recall during a pain-task in healthy participants.

    Science.gov (United States)

    Carstens, Johan K P; Boersma, Katja; Schrooten, Martien G S; Linton, Steven J

    2017-10-01

    Increasing recall of instructions and advice in a pain consultation is important, since it is a prerequisite for adherence to treatment recommendations. However, interference due to pain-related distress may result in poor recall. Whereas there are some indications that recall can be increased by empathic communication that reduces interference, this interesting possibility remains largely untested experimentally. The current experiment aimed at studying effects of empathic communication, and more specifically validation, on recall during a pain test and possible mediators and moderators of this effect. Participants received either validating (N=25) or invalidating responses (N=25) from the experimenter during a pain provoking task, followed by self-report measures of interference (affect, situational pain catastrophizing) and recall (accurate and false memories of words). As expected, the validated group exhibited higher accurate recall and less false memories following the pain test as compared to the invalidated group. This was partly due to the effect of interference being counteracted by moderating the relationship between pain catastrophizing and recall. These novel results suggest that validating communication can counteract interference due to pain catastrophizing on recall, at least in a controlled experimental setting. Good communication by health professionals is of utmost importance for adherence to pain management. The current results expand our knowledge on the effects of pain communication by establishing and explaining a clear link between empathic communication and recall, highlighting the role of pain catastrophizing. Copyright © 2017 Scandinavian Association for the Study of Pain. Published by Elsevier B.V. All rights reserved.

  20. Substance P and beta-endorphin mediate electro-acupuncture induced analgesia in mouse cancer pain model

    Directory of Open Access Journals (Sweden)

    Kim Sun-Hyung

    2009-07-01

    Full Text Available Abstract Background Opioid analgesics are generally used to combat the pain associated with cancerous conditions. These agents not only inhibit respiratory function and cause constipation, but also induce other significant side effects such as addiction and tolerance, all of which further contribute to a reduced quality of life for cancer patients. Thus, in the present study, the effects of electro-acupuncture treatment (EA on mechanical allodynia were examined in a cancer pain mouse model. Methods In order to produce a neuropathic cancer pain model, S-180 sarcoma cells were inoculated around the sciatic nerve of left legs of Balb/c mice. Magnetic Resonance Imaging (MRI scanning confirmed the mass of S-180 cancer cells embedded around the sciatic nerve. Mechanical allodynia was most consistently induced in the mouse sarcoma cell line S-180 (2 × 106sarcoma cells-treated group compared to all the other groups studied. EA stimulation (2 Hz was administered daily to ST36 (Zusanli of S-180 bearing mice for 30 min for 9 days after S-180 inoculation. Results EA treatment significantly prolonged paw withdrawal latency from 5 days after inoculation. It also shortened the cumulative lifting duration from 7 days after inoculation, compared to the tumor control. Also, the overexpression of pain peptide substance P in the dorsal horn of the spinal cord was significantly decreased in the EA-treated group compared to the tumor control on Day 9 post inoculation. Furthermore, EA treatment effectively increased the concentration of β-endorphin in blood and brain samples of the mice to a greater extent than that of the tumor control as well as the normal group. The concentration of β-endorphin for EA treatment group increased by 51.457% in the blood and 12.6% in the brain respectively, compared to the tumor control group. Conclusion The findings of this study suggest that a S-180 cancer pain model is useful as a consistent and short time animal model. It also

  1. Combined electric and pressure cuff pain stimuli for assessing conditioning pain modulation (CPM).

    Science.gov (United States)

    Tsukamoto, M; Petersen, K K; Mørch, C D; Arendt-Nielsen, L

    2017-12-29

    Aims Traditionally, conditioning pain modulation (CPM) can be assessed by applying a test stimulus (TS) before and after application of a conditioning stimulus (CS), which is normally applied extra-segmental. Currently, no studies have attempted to apply the TS and CS to the same site using different stimuli modalities. The aim of this study was to evaluate electrical TS and cuff pressure CS applied to the same experimental site for studying CPM. Methods 20 male volunteers participated in this study, which consisted of stimulations applied by a cuff-algometer (NociTech and Aalborg University, Denmark) and current stimulator (Digitimer DS5, UK), through two Ag/AgCl electrodes (Ambu® Neuroline 700, Denmark). The cuff was wrapped around the lower leg and stimulation electrodes were placed under the cuff and to the same location on the contralateral leg. Electrical TS were applied to the non-dominant leg with or without cuff pressure CS on the dominant (CS1) or the same (non-dominant) leg (CS2, electrode under cuff). The subjects were instructed to rate the electrical evoked pain intensity on a 10-cm continuous visual analog scale (VAS, "0" represented "no pain", and "10" represented "maximal pain"). The pain detection threshold (PDT) was defined as "1" on the VAS scale. Results There was no significant deference in PDT for neither CS1 nor CS2. A median split subanalysis on CPM-responders versus CPM-nonresponders to the TS + CS1 combination. Using this grouping, there was significant increase in PDT when comparing TS to TS + CS1 or TS + CS2 (4.0 mA vs 5.6 mA; P CPM can be evoked in a subgroup of subjects by applying the electrical test stimulus and cuff pressure conditioning stimuli to the same experimental site.

  2. [Historical pain concepts : Cultural influences on pain perception and interpretation].

    Science.gov (United States)

    Schäfer, D

    2017-02-01

    In the age of globalization and cultural diversification differing concepts of pain in patient care are of increasing importance. Historical models of the origin and interpretation of pain, which in this article are presented in a cursory and exemplary way, help to understand the panoply of modern concepts outside of medicine. Basically, pain was viewed not only in religion and philosophy but also by premodern physicians as a psychophysical phenomenon crucially depending on the determination by a "soul" therefore creating therapeutic options even before the discovery of an effective analgesia. Furthermore, the historical interpretations of pain in and outside of medicine can still be of profound importance to patients even today.

  3. Perinatal maternal stress and serotonin signaling: effects on pain sensitivity in offspring.

    Science.gov (United States)

    Knaepen, Liesbeth; Pawluski, Jodi L; Patijn, Jacob; van Kleef, Maarten; Tibboel, Dick; Joosten, Elbert A

    2014-07-01

    It has been estimated that 20% of pregnant women are facing perinatal stress and depression. Perinatal maternal stress has been shown to increase pain sensitivity in offspring. For the treatment of their depressive symptoms, pregnant women are frequently prescribed selective serotonin reuptake inhibitors (SSRIs). Since the descending pain inhibitory circuit matures perinatally, perinatal SSRI exposure has been shown to affect pain sensitivity in offspring. In the present review, we summarize experimental and clinical evidence for the effect of perinatal maternal stress and SSRI exposure on pain sensitivity in offspring. Both experimental and clinical studies show the effect of perinatal maternal stress on regulation of the hypothalamic-pituitary-adrenal (HPA) system and the serotonin pain inhibitory system. Alterations in these two systems likely underlie long-term alterations in the development of pain sensitivity. This review sheds light on the effect of perinatal maternal stress and treatment with SSRIs on offspring pain sensitivity, in relation to the developing HPA system and 5-HT signaling. © 2013 Wiley Periodicals, Inc.

  4. New experimental model for training in videosurgery Novo modelo experimental para treinamento em videocirurgia

    Directory of Open Access Journals (Sweden)

    Danilo Malta Batista

    2012-10-01

    Full Text Available PURPOSE: To develop a new experimental model of lower cost for training in videosurgery. METHODS: This project was performed at the Nucleus of Experimental Surgery of the Bahiana School of Medicine and Public Health, based on previous models described in the literature and under the supervision of the full professor of Operative Technique and Experimental Surgery II. It was made a model cube-shaped, made of wood, with holes distributed in various locations, rubber stoppers for the holes and lined externally with carpet, and internally with laminate. RESULTS: The new experimental model is of low cost and reproduces quite faithfully several videosurgical procedures. CONCLUSION: Medical schools interested in the subject may adopt the new model for training in videosurgery without the need of high costs for making and using these models.OBJETIVO: Desenvolver um novo modelo experimental de baixo custo para treinamento em videocirurgia MÉTODOS: Este projeto foi conduzido no Núcleo de Cirurgia Experimental da Escola Bahiana de Medicina e Saúde Pública, baseado em modelos prévios descritos na literatura e sob a supervisão do professor titular de Técnica Operatória e Cirurgia Experimental II. Foi feito um modelo em formato de cubo, de madeira, com furos distribuídos em vários locais, tampas de borracha para os orifícios e forrado externamente com carpete e internamente com laminado. RESULTADOS: O novo modelo experimental desenvolvido é de baixo custo e reproduz de forma bastante fiel diversos procedimentos videocirúrgicos. CONCLUSÃO: Faculdades médicas interessadas no tema poderão adotar o novo modelo para o treinamento em videocirurgia sem que sejam necessários gastos elevados para a confecção e o uso desses modelos.

  5. Painful Na-channelopathies: an expanding universe.

    Science.gov (United States)

    Waxman, Stephen G

    2013-07-01

    The universe of painful Na-channelopathies--human disorders caused by mutations in voltage-gated sodium channels--has recently expanded in three dimensions. We now know that mutations of sodium channels cause not only rare genetic 'model disorders' such as inherited erythromelalgia and channelopathy-associated insensitivity to pain but also common painful neuropathies. We have learned that mutations of NaV1.8, as well as mutations of NaV1.7, can cause painful Na-channelopathies. Moreover, recent studies combining atomic level structural models and pharmacogenomics suggest that the goal of genomically guided pain therapy may not be unrealistic. Copyright © 2013 Elsevier Ltd. All rights reserved.

  6. Poly(ADP-ribose) polymerase inhibition reveals a potential mechanism to promote neuroprotection and treat neuropathic pain

    OpenAIRE

    Komirishetty, Prashanth; Areti, Aparna; Gogoi, Ranadeep; Sistla, Ramakrishna; Kumar, Ashutosh

    2016-01-01

    Neuropathic pain is triggered by the lesions to peripheral nerves which alter their structure and function. Neuroprotective approaches that limit the pathological changes and improve the behavioral outcome have been well explained in different experimental models of neuropathy but translation of such strategies to clinics has been disappointing. Experimental evidences revealed the role of free radicals, especially peroxynitrite after the nerve injury. They provoke oxidative DNA damage and con...

  7. Pain and pharmacologic pain management in long-stay nursing home residents.

    Science.gov (United States)

    Hunnicutt, Jacob N; Ulbricht, Christine M; Tjia, Jennifer; Lapane, Kate L

    2017-06-01

    Previous studies estimate that >40% of long-stay nursing home (NH) residents experience persistent pain, with 20% of residents in pain receiving no analgesics. Strengthened NH surveyor guidance and improved pain measures on the Minimum Data Set 3.0 were introduced in March 2009 and October 2010, respectively. This study aimed to provide estimates after the important initiatives of (1) prevalence and correlates of persistent pain; and (2) prevalence and correlates of untreated or undertreated persistent pain. We identified 1,387,405 long-stay residents in U.S. NHs between 2011 and 2012 with 2 Minimum Data Set assessments 90 days apart. Pain was categorized as persistent (pain on both assessments), intermittent (pain on either assessment), or none. Pharmacologic pain management was classified as untreated pain (no scheduled or as needed medications received) or potentially undertreated (no scheduled received). Modified Poisson models adjusting for resident clustering within NHs provided adjusted prevalence ratios (APRs) estimates and 95% confidence intervals (CIs). The prevalence of persistent and intermittent pain was 19.5% and 19.2%, respectively, but varied substantially by age, sex, race and ethnicity, cognitive impairment, and cancer. Of residents in persistent pain, 6.4% and 32.0% were untreated and undertreated, respectively. Racial and ethnic minorities (non-Hispanic blacks vs whites, APR = 1.19, 95% CI: 1.13-1.25) and severely cognitively impaired residents (severe vs no/mild APR = 1.51, 95% CI: 1.44-1.57) had an increased prevalence of untreated and undertreated pain. One in 5 NH residents has persistent pain. Although this estimate is greatly improved, many residents may be undertreated. The disturbing disparities in untreated and undertreated pain need to be addressed.

  8. The efficacy of pain neuroscience education on musculoskeletal pain: A systematic review of the literature.

    Science.gov (United States)

    Louw, Adriaan; Zimney, Kory; Puentedura, Emilio J; Diener, Ina

    2016-07-01

    Systematic review of randomized control trials (RCTs) for the effectiveness of pain neuroscience education (PNE) on pain, function, disability, psychosocial factors, movement, and healthcare utilization in individuals with chronic musculoskeletal (MSK) pain. Systematic searches were conducted on 11 databases. Secondary searching (PEARLing) was undertaken, whereby reference lists of the selected articles were reviewed for additional references not identified in the primary search. All experimental RCTs evaluating the effect of PNE on chronic MSK pain were considered for inclusion. Additional Limitations: Studies published in English, published within the last 20 years, and patients older than 18 years. No limitations were set on specific outcome measures. Data were extracted using the participants, interventions, comparison, and outcomes (PICO) approach. Study quality of the 13 RCTs used in this review was assessed by 2 reviewers using the PEDro scale. Narrative summary of results is provided for each study in relation to outcomes measurements and effectiveness. Current evidence supports the use of PNE for chronic MSK disorders in reducing pain and improving patient knowledge of pain, improving function and lowering disability, reducing psychosocial factors, enhancing movement, and minimizing healthcare utilization.

  9. Attention to pain! A neurocognitive perspective on attentional modulation of pain in neuroimaging studies.

    Science.gov (United States)

    Torta, D M; Legrain, V; Mouraux, A; Valentini, E

    2017-04-01

    Several studies have used neuroimaging techniques to investigate brain correlates of the attentional modulation of pain. Although these studies have advanced the knowledge in the field, important confounding factors such as imprecise theoretical definitions of attention, incomplete operationalization of the construct under exam, and limitations of techniques relying on measuring regional changes in cerebral blood flow have hampered the potential relevance of the conclusions. Here, we first provide an overview of the major theories of attention and of attention in the study of pain to bridge theory and experimental results. We conclude that load and motivational/affective theories are particularly relevant to study the attentional modulation of pain and should be carefully integrated in functional neuroimaging studies. Then, we summarize previous findings and discuss the possible neural correlates of the attentional modulation of pain. We discuss whether classical functional neuroimaging techniques are suitable to measure the effect of a fluctuating process like attention, and in which circumstances functional neuroimaging can be reliably used to measure the attentional modulation of pain. Finally, we argue that the analysis of brain networks and spontaneous oscillations may be a crucial future development in the study of attentional modulation of pain, and why the interplay between attention and pain, as examined so far, may rely on neural mechanisms shared with other sensory modalities. Copyright © 2017 Elsevier Ltd. All rights reserved.

  10. Happiness, Pain Intensity, Pain Interference, and Distress in Individuals with Physical Disabilities.

    Science.gov (United States)

    Müller, Rachel; Terrill, Alexandra L; Jensen, Mark P; Molton, Ivan R; Ravesloot, Craig; Ipsen, Catherine

    2015-12-01

    The aim of this study was to examine how the construct of happiness is related to pain intensity, pain interference, and distress in individuals with physical disabilities. This study involves cross-sectional analyses of 471 individuals with a variety of health conditions reporting at least mild pain. The first hypothesis that happiness mediates the relationship between pain intensity and two outcomes, pain interference and distress, was not supported. The second hypothesis was supported by a good fitting model (χ2(10) = 12.83, P = 0.23, root-mean-square error of approximation = 0.025) and indicated that pain intensity significantly mediated the effect of happiness on pain interference (indirect effect: β = -0.13, P Happiness showed a significant direct effect on pain intensity (β = -0.20, P happiness components meaning, pleasure, and engagement fitted well (χ2(4) = 9.65, P = 0.05, root-mean-square error of approximation = 0.055). Pain intensity acted as a significant mediator but only mediated the effect of meaning on pain interference (indirect effect: β = -0.07, P = 0.05) and on distress (indirect effect via pain interference: β = -0.04, P = 0.05). Only meaning (β = -0.10, P = 0.05), but neither pleasure nor engagement, had a significant direct effect on pain intensity. Participants who reported greater happiness reported lower pain interference and distress through happiness' effects on pain intensity. Experiencing meaning and purpose in life seems to be most closely (and negatively) associated with pain intensity, pain interference, and distress. Findings from this study can lay the groundwork for intervention studies to better understand how to more effectively decrease pain intensity, pain interference, and distress.

  11. Gastroprotective effect of Senecio candicans DC on experimental ulcer models.

    Science.gov (United States)

    Hariprasath, Lakshmanan; Raman, Jegadeesh; Nanjian, Raaman

    2012-03-06

    Senecio candicans DC (Asteraceae) is used as a remedy for gastric ulcer and stomach pain in the Nilgiris district, Tamil Nadu for which no scientific evidence exists. The present study was performed to evaluate the gastroprotective effects and acute oral toxicity of aqueous leaf extract of Senecio candicans (AESC) in experimental models. The antiulcerogenic activity of AESC was performed in two different ulcer models viz., pylorus-ligated model and ethanol-induced model using Wistar albino rats. Acute toxicity study was also performed to get information on the admissible dose for treatment of ulcer. Preliminary phytochemical screening of AESC was performed to find the active principles present, which are thus responsible for the antiulcerogenic activity. DPPH assay was performed to confirm the antioxidant activity of AESC. The acute toxicity study did not show any mortality up to 2500mg/kg b.w. of AESC. Both the ulcer models showed gastroprotective effect comparable to that of the standard Omeprazole. The results of antioxidant enzymes, histopathology sections, ATPase and mucus content of gastric secretion showed that several mechanisms are involved in the gastroprotective effect. The preliminary phytochemical screening revealed the presence of alkaloids, flavonoids and steroids in AESC. The DPPH assay confirmed the antioxidant activity of AESC. The traditional consumption of AESC for the treatment of gastric ulcer is thus true, the antioxidant constituents present in the extract plays a major role in the gastroprotective activity, but since Senecio species are known for the presence of pyrrolizidine alkaloids, a detailed study in future is required to describe the safe dose for a prolonged period. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

  12. The role of c-AMP-dependent protein kinase in spinal cord and post synaptic dorsal column neurons in a rat model of visceral pain.

    Science.gov (United States)

    Wu, Jing; Su, Guangxiao; Ma, Long; Zhang, Xuan; Lei, Yongzhong; Lin, Qing; Nauta, Haring J W; Li, Junfa; Fang, Li

    2007-04-01

    Visceral noxious stimulation induces central neuronal plasticity changes and suggests that the c-AMP-dependent protein kinase (PKA) signal transduction cascade contributes to long-term changes in nociceptive processing at the spinal cord level. Our previous studies reported the clinical neurosurgical interruption of post synaptic dorsal column neuron (PSDC) pathway by performing midline myelotomy effectively alleviating the intractable visceral pain in patients with severe pain. However, the intracellular cascade in PSDC neurons mediated by PKA nociceptive neurotransmission was not known. In this study, by using multiple experimental approaches, we investigated the role of PKA in nociceptive signaling in the spinal cord and PSDC neurons in a visceral pain model in rats with the intracolonic injection of mustard oil. We found that mustard oil injection elicited visceral pain that significantly changed exploratory behavior activity in rats in terms of decreased numbers of entries, traveled distance, active and rearing time, rearing activity and increased resting time when compared to that of rats receiving mineral oil injection. However, the intrathecal infusion of PKA inhibitor, H89 partially reversed the visceral pain-induced effects. Results from Western blot studies showed that mustard oil injection significantly induced the expression of PKA protein in the lumbosacral spinal cord. Immunofluorescent staining in pre-labeled PSDC neurons showed that mustard oil injection greatly induces the neuronal profile numbers. We also found that the intrathecal infusion of a PKA inhibitor, H89 significantly blocked the visceral pain-induced phosphorylation of c-AMP-responsive element binding (CREB) protein in spinal cord in rats. The results of our study suggest that the PKA signal transduction cascade may contribute to visceral nociceptive changes in spinal PSDC pathways.

  13. Emotion regulatory function of parent attention to child pain and associated implications for parental pain control behaviour.

    Science.gov (United States)

    Vervoort, Tine; Trost, Zina; Sütterlin, Stefan; Caes, Line; Moors, Agnes

    2014-08-01

    We investigated the function of parental attention to child pain in regulating parental distress and pain control behaviour when observing their child performing a painful (cold pressor) task (CPT); we also studied the moderating role of parental state anxiety. Participants were 62 schoolchildren and one of their parents. Parental attention towards or away from child pain (ie, attend to pain vs avoid pain) was experimentally manipulated during a viewing task pairing unfamiliar children's neutral and pain faces. Before and after the viewing task, parental distress regulation was assessed by heart rate (HR) and heart rate variability (HRV). In a subsequent phase, parents observed their own child perform a CPT task, allowing assessment of parental pain control behaviour (indexed by latency to stop their child's CPT performance) and parental distress, which was assessed via self-report before and after observation of child CPT performance. Eye tracking during the viewing task and self-reported attention to own child's pain confirmed successful attention manipulation. Further, findings indicated that the effect of attentional strategy on parental emotion regulation (indexed by HR, self-report) and pain control behaviour depended on parents' state anxiety. Specifically, whereas low anxious parents reported more distress and demonstrated more pain control behaviour in the Attend to Pain condition, high anxious parents reported more distress and showed more pain control behaviour in the Avoid Pain condition. This inverse pattern was likewise apparent in physiological distress indices (HR) in response to the initial viewing task. Theoretical/clinical implications and further research directions are discussed. Copyright © 2014 International Association for the Study of Pain. Published by Elsevier B.V. All rights reserved.

  14. Analgesic effect of the neuropeptide cortistatin in murine models of arthritic inflammatory pain.

    Science.gov (United States)

    Morell, Maria; Souza-Moreira, Luciana; Caro, Marta; O'Valle, Francisco; Forte-Lago, Irene; de Lecea, Luis; Gonzalez-Rey, Elena; Delgado, Mario

    2013-05-01

    To investigate the role of the antiinflammatory neuropeptide cortistatin in chronic pain evoked by joint inflammation. Thermal and mechanical hyperalgesia was evoked in mouse knee joints by intraplantar injection of tumor necrosis factor α and intraarticular infusion of Freund's complete adjuvant, and the analgesic effects of cortistatin, administered centrally, peripherally, and systemically, were assessed. In addition, the effects of cortistatin on the production of nociceptive peptides and the activation of pain signaling were assayed in dorsal root ganglion cultures and in inflammatory pain models. The role of endogenous cortistatin in pain sensitization and perpetuation of chronic inflammatory states was evaluated in cortistatin-deficient mice. Finally, the effect of noxious/inflammatory stimuli in the production of cortistatin by the peripheral nociceptive system was assayed in vitro and in vivo. Expression of cortistatin was observed in peptidergic nociceptors of the peripheral nociceptive system, and endogenous cortistatin was found to participate in the tuning of pain sensitization, especially in pathologic inflammatory conditions. Results showed that cortistatin acted both peripherally and centrally to reduce the tactile allodynia and heat hyperalgesia evoked by arthritis and peripheral tissue inflammation in mice, via mechanisms that were independent of its antiinflammatory action. These mechanisms involved direct action on nociceptive neurons and regulation of central sensitization. The analgesic effects of cortistatin in murine arthritic pain were linked to binding of the neuropeptide to somatostatin and ghrelin receptors, activation of the G protein subunit Gαi , impairment of ERK signaling, and decreased production of calcitonin gene-related peptide in primary nociceptors. These findings indicate that cortistatin is an antiinflammatory factor with potent analgesic effects that may offer a new approach to pain therapy in pathologic inflammatory

  15. Pharmacological kynurenine 3-monooxygenase enzyme inhibition significantly reduces neuropathic pain in a rat model.

    Science.gov (United States)

    Rojewska, Ewelina; Piotrowska, Anna; Makuch, Wioletta; Przewlocka, Barbara; Mika, Joanna

    2016-03-01

    Recent studies have highlighted the involvement of the kynurenine pathway in the pathology of neurodegenerative diseases, but the role of this system in neuropathic pain requires further extensive research. Therefore, the aim of our study was to examine the role of kynurenine 3-monooxygenase (Kmo), an enzyme that is important in this pathway, in a rat model of neuropathy after chronic constriction injury (CCI) to the sciatic nerve. For the first time, we demonstrated that the injury-induced increase in the Kmo mRNA levels in the spinal cord and the dorsal root ganglia (DRG) was reduced by chronic administration of the microglial inhibitor minocycline and that this effect paralleled a decrease in the intensity of neuropathy. Further, minocycline administration alleviated the lipopolysaccharide (LPS)-induced upregulation of Kmo mRNA expression in microglial cell cultures. Moreover, we demonstrated that not only indirect inhibition of Kmo using minocycline but also direct inhibition using Kmo inhibitors (Ro61-6048 and JM6) decreased neuropathic pain intensity on the third and the seventh days after CCI. Chronic Ro61-6048 administration diminished the protein levels of IBA-1, IL-6, IL-1beta and NOS2 in the spinal cord and/or the DRG. Both Kmo inhibitors potentiated the analgesic properties of morphine. In summary, our data suggest that in neuropathic pain model, inhibiting Kmo function significantly reduces pain symptoms and enhances the effectiveness of morphine. The results of our studies show that the kynurenine pathway is an important mediator of neuropathic pain pathology and indicate that Kmo represents a novel pharmacological target for the treatment of neuropathy. Copyright © 2015 Elsevier Ltd. All rights reserved.

  16. Catecholamine-o-methyltransferase polymorphisms are associated with postoperative pain intensity.

    LENUS (Irish Health Repository)

    Lee, Peter J

    2011-02-01

    single nucleotide polymorphisms (SNPs) in the genes for catecholamine-O-methyltransferase (COMT), μ-opioid receptor and GTP cyclohydrolase (GCH1) have been linked to acute and chronic pain states. COMT polymorphisms are associated with experimental pain sensitivity and a chronic pain state. No such association has been identified perioperatively. We carried out a prospective observational clinical trial to examine associations between these parameters and the development of postoperative pain in patients undergoing third molar (M3) extraction.

  17. Few promising multivariable prognostic models exist for recovery of people with non-specific neck pain in musculoskeletal primary care: A systematic review

    NARCIS (Netherlands)

    R.W. Wingbermühle (Roel); E. van Trijffel (Emiel); Nelissen, P.M. (Paul M.); B.W. Koes (Bart); A.P. Verhagen (Arianne)

    2017-01-01

    markdownabstractQuestion: Which multivariable prognostic model(s) for recovery in people with neck pain can be used in primary care? Design: Systematic review of studies evaluating multivariable prognostic models. Participants: People with non-specific neck pain presenting at primary care.

  18. Effects of an intervention based on the Transtheoretical Model on back muscle endurance, physical function and pain in rice farmers with chronic low back pain.

    Science.gov (United States)

    Thanawat, Thanakorn; Nualnetr, Nomjit

    2017-01-01

    Chronic low back pain (LBP) can be managed by exercises which should be tailored to an individual's readiness to behavioral change. To evaluate the effects of an intervention program based on the Transtheoretical Model of behavioral change (TTM) on back muscle endurance, physical function and pain in rice farmers with chronic LBP. In a 32-week study, 126 rice farmers were allocated to the TTM (n= 62) and non-TTM (n= 64) groups. Modified Biering-Sorensen test, Oswestry Disability Questionnaire and visual analogue scale were used for evaluating back muscle endurance, physical function and severity of pain, respectively. The evaluations were performed at baseline and at weeks 8, 20 and 32 of the study. Data were analyzed using repeated measure ANOVA. The back muscle endurance was significantly greater in the TTM group than in the non-TTM group at week 32 (p= 0.025). Physical function and severity of pain were significantly improved in the TTM group when compared with the non-TTM group at weeks 20 and 32 (pback muscle endurance and physical function, and reduce the pain in rice farmers with LBP. Further studies should be considered to explore the long-term effects of this intervention.

  19. The Relationship Between Posttraumatic Stress Disorder and Chronic Pain in People Seeking Treatment for Chronic Pain: The Mediating Role of Psychological Flexibility.

    Science.gov (United States)

    Åkerblom, Sophia; Perrin, Sean; Rivano Fischer, Marcelo; McCracken, Lance M

    2018-06-01

    The symptoms of posttraumatic stress disorder (PTSD) and chronic pain are thought to interact to increase the severity and impact of both conditions, but the mechanisms by which they interact remain unclear. This study examines the relationship between PTSD and chronic pain and whether indices of Psychological Flexibility mediate the relationship between these 2 conditions. Standardized self-report measures of PTSD, pain severity, pain interference, depression, and psychological flexibility (pain-related acceptance, committed action, cognitive fusion, and values-based action) were obtained from 315 people seeking treatment for chronic pain who also reported at least 1 traumatic experience. People seeking treatment for chronic pain and reporting symptoms consistent with a current diagnosis of PTSD had significantly higher levels of pain severity, pain interference, depression, and cognitive fusion and lower levels of pain-related acceptance and committed action than those reporting symptoms below the diagnostic threshold for PTSD. Pain-related acceptance, committed action, cognitive fusion, and depression mediated the relationship between PTSD and pain severity/interference, with pain-related acceptance being the strongest mediator from the Psychological Flexibility model. Processes from the Psychological Flexibility model were identified as mediators of the relationship between PTSD and chronic pain in people seeking treatment for chronic pain. The Psychological Flexibility model may be useful as an overarching model to help understand the relationship between PTSD and chronic pain. It is possible that targeting pain-related acceptance, committed action, and cognitive fusion (among other processes) in the treatment of chronic pain may produce corresponding improvements in comorbid symptoms of PTSD when these are present and may reduce impacts of PTSD on outcomes of chronic pain. Conversely, targeting of these processes in the treatment of PTSD may produce similar

  20. The effect of local/topical analgesics on incisional pain in a pig model

    Directory of Open Access Journals (Sweden)

    Castel D

    2017-09-01

    Full Text Available David Castel,1 Itai Sabbag,2 Sigal Meilin3 1The Neufeld Cardiac Research Institute, Sheba Medical Centre, Sackler School of Medicine, Tel-Aviv University, Tel-Aviv, 2Lahav Research Institute, Kibutz Lahav, Negev, 3Neurology R&D Division, MD Biosciences, Nes-Ziona, Israel Abstract: Interest in the development of new topical/local drug administration for blocking pain at peripheral sites, with maximum drug activity and minimal systemic effects, is on the rise. In the review article by Kopsky and Stahl, four critical barriers in the process of research and development of topical analgesics were indicated. The active pharmaceutical ingredient (API and the formulation are among the major challenges. The road to the development of such drugs passes through preclinical studies. These studies, if planned correctly, should serve as guidance for choosing the right API and formulation. Although rodent models for pain continue to provide valuable data on the mechanisms driving pain, their use in developing topical and localized treatment approaches is limited for technical (intraplate injection area is small as well as mechanical reasons (non-similarity to human skin and innervation. It has been previously shown that pigs are comparable to humans in ways that make them a better choice for evaluating topical and local analgesics. The aim of this study was to summarize several experiments that used pigs for testing postoperative pain in an incisional pain model (skin incision [SI] and skin and muscle incision [SMI]. At the end of the surgery, the animals were treated with different doses of bupivacaine solution (Marcaine®, bupivacaine liposomal formulation (Exparel® or ropivacaine solution (Naropin. Von Frey testing demonstrated a decrease in the animals’ sensitivity to mechanical stimulation expressed as an increase in the withdrawal force following local treatment. These changes reflect the clinical condition in the level as well as in the duration of

  1. Uso do laser, 670 nm, no quadro álgico de ratos submetidos à modelo experimental de ciatalgia Use of laser, 670 nm, in painful episodes of rats submitted to experimental model of sciatica

    Directory of Open Access Journals (Sweden)

    Núbia Broetto Cunha

    2008-04-01

    Full Text Available A ciatalgia deve-se a compressão do nervo isquiático em algum ponto de seu trajeto, e seu tratamento consiste em solucionar a causa da compressão nervosa, seja por tratamento cirúrgico ou conservador. Alguns recursos fisioterapêuticos atuam basicamente na redução dos sintomas ocasionados por este distúrbio. O objetivo deste estudo foi verificar a eficácia do laser 670 nm, em duas diferentes densidades de energia, na redução do quadro álgico, em ratos submetidos a modelo experimental de ciatalgia. Foram utilizados 18 ratos, divididos em 3 grupos: G1 (n=6 submetidos à ciatalgia e simulado o tratamento (grupo placebo, G2 (n=6 submetido à ciatalgia e tratados com laser 2 J/cm², G3 (n=6 submetidos à ciatalgia e irradiados com laser 4 J/cm². O nervo isquiático do membro posterior direito dos animais foi exposto e compressão com fio catgut em 4 pontos ao redor do nervo foi realizada. No 3° dia pós-operatório, iniciou-se o tratamento com laser na região do procedimento cirúrgico do membro posterior direito durante 10 dias consecutivos. Verificou-se por meio da marcha, o tempo em que o membro permanecia no ar nos períodos: anterior à ciatalgia, pré e pós-tratamento. Os resultados demonstraram que o laser não foi eficaz na redução do quadro álgico, porém com 4 J/cm² houve efeito positivo, sem restabelecimento completo da funcionalidade.Sciatica is caused by the sciatic nerve compression in some point of its course, and its treatment consists of solving the nervous compression cause, either by surgical or conservative treatment. Some physiotherapeutic resources act basically in the reduction of the symptoms caused by this disturbance. The aim of this study was to verify the effectiveness of the laser 670 nm, in two different energy densities, in the pain reduction, in rats submitted to a sciatica experimental model. Eighteen rats, divided in 3 groups were used: G1 (n=6 submitted to sciatica and simulated treatment (placebo

  2. Ciguatoxins activate specific cold pain pathways to elicit burning pain from cooling

    OpenAIRE

    Vetter, Irina; Touska, Filip; Hess, Andreas; Hinsbey, Rachel; Sattler, Simon; Lampert, Angelika; Sergejeva, Marina; Sharov, Anastasia; Collins, Lindon S; Eberhardt, Mirjam; Engel, Matthias; Cabot, Peter J; Wood, John N; Vlachová, Viktorie; Reeh, Peter W

    2012-01-01

    Ciguatoxins derived from fish lead to cold allodynia in humans, the perception of intense burning pain in response to mild cooling. A novel mouse model of ciguatoxin-induced cold allodynia reveals that ciguatoxin activates the TRPA1 thermosensitive ion channel to mediate pain perception.

  3. The Ehrlich Tumor Induces Pain-Like Behavior in Mice: A Novel Model of Cancer Pain for Pathophysiological Studies and Pharmacological Screening

    Directory of Open Access Journals (Sweden)

    Cassia Calixto-Campos

    2013-01-01

    Full Text Available The Ehrlich tumor is a mammary adenocarcinoma of mice that can be developed in solid and ascitic forms depending on its administration in tissues or cavities, respectively. The present study investigates whether the subcutaneous plantar administration of the Ehrlich tumor cells induces pain-like behavior and initial pharmacological susceptibility characteristics. The Ehrlich tumor cells (1 × 104–107 cells induced dose-dependent mechanical hyperalgesia (electronic version of the von Frey filaments, paw edema/tumor growth (caliper, and flinches compared with the saline group between days 2 and 12. There was no difference between doses of cells regarding thermal hyperalgesia in the hot-plate test. Indomethacin (a cyclooxygenase inhibitor and amitriptyline hydrochloride (a tricyclic antidepressant treatments did not affect flinches or thermal and mechanical hyperalgesia. On the other hand, morphine (an opioid inhibited the flinch behavior and the thermal and mechanical hyperalgesia. These effects of morphine on pain-like behavior were prevented by naloxone (an opioid receptor antagonist treatment. None of the treatments affected paw edema/tumor growth. The results showed that, in addition to tumor growth, administration of the Ehrlich tumor cells may represent a novel model for the study of cancer pain, specially the pain that is susceptible to treatment with opioids, but not to cyclooxygenase inhibitor or to tricyclic antidepressant.

  4. Impact of Psychological Stress on Pain Perception in an Animal Model of Endometriosis.

    Science.gov (United States)

    Hernandez, Siomara; Cruz, Myrella L; Seguinot, Inevy I; Torres-Reveron, Annelyn; Appleyard, Caroline B

    2017-10-01

    Pain in patients with endometriosis is considered a significant source of stress but does not always correlate with severity of the condition. We have demonstrated that stress can worsen endometriosis in an animal model. Here, we tested the impact of a psychological stress protocol on pain thresholds and pain receptors. Endometriosis was induced in female rats by suturing uterine horn tissue next to the intestinal mesentery. Sham rats had sutures only. Rats were exposed to water avoidance stress for 7 consecutive days or handled for 5 minutes (no stress). Fecal pellets and serum corticosterone (CORT) levels were measured as an index of anxiety. Pain perception was assessed using hot plate and Von Frey tests. Substance P, enkephalin, endomorphin-2, Mu opioid receptor (MOR), and neurokinin-1 receptor expression in the spinal cord were measured by immunohistochemistry. Fecal pellets and CORT were significantly higher in the endo-stress (ES) group than endo-no stress (ENS; P stress groups (SNS; P stress reversed the allodynic effect caused by endo ( P stress develop more severe symptoms but interestingly stress seems to have beneficial effects on abdominal allodynia, which could be a consequence of the stress-induced analgesia phenomenon.

  5. Variability in negative emotions among individuals with chronic low back pain: relationships with pain and function.

    Science.gov (United States)

    Gerhart, James I; Burns, John W; Bruehl, Stephen; Smith, David A; Post, Kristina M; Porter, Laura S; Schuster, Erik; Buvanendran, Asokumar; Fras, Anne Marie; Keefe, Francis J

    2017-11-13

    Chronic pain is associated with elevated negative emotions, and resources needed to adaptively regulate these emotions can be depleted during prolonged pain. Studies of links between pain, function, and negative emotions in people with chronic pain, however, have focused almost exclusively on relationships among mean levels of these factors. Indexes that may reflect aspects of emotion regulation have typically not been analyzed. We propose that 1 index of emotion regulation is variability in emotion over time as opposed to average emotion over time. The sample was 105 people with chronic low back pain and 105 of their pain-free spouses. They completed electronic diary measures 5x/d for 14 consecutive days, producing 70 observations per person from which we derived estimates of within-subject variance in negative emotions. Location-scale models were used to simultaneously model predictors of both mean level and variance in patient negative emotions over time. Patients reported significantly more variability in negative emotions compared to their spouses. Patients who reported higher average levels of pain, pain interference, and downtime reported significantly higher levels of variability in negative emotions. Spouse-observed pain and pain behaviors were also associated with greater variability in patients' negative emotions. Test of the inverse associations between negative emotion level and variability in pain and function were significant but weaker in magnitude. These findings support the notion that chronic pain may erode negative emotion regulation resources, to the potential detriment of intra- and inter-personal function.

  6. Pain perception description after advanced surface ablation

    Directory of Open Access Journals (Sweden)

    Sobas EM

    2017-04-01

    Full Text Available Eva M Sobas,1,2 Sebastián Videla,3,4 Amanda Vázquez,1 Itziar Fernández,1,5 Miguel J Maldonado,1 José-Carlos Pastor1,6,7 1Instituto Universitario de Oftalmobiología Aplicada (IOBA, Universidad de Valladolid, Valladolid, Spain; 2Facultad de Enfermería, Universidad de Valladolid, Valladolid Spain; 3Laboratorios Dr. Esteve S.A., Barcelona, Spain; 4Department of Experimental and Health Sciences, Facultad de Ciencias de la Salud y de la Vida, Universidad Pompeu Fabra, Barcelona, Spain; 5Networking Research Center on Bioengineering, Biomaterials and Nanomedicine (CIBER-BBN, Valladolid, Spain; 6Department of Ophthalmology, Hospital Clínico Universitario, Valladolid, Spain; 7Department of Surgery, Ophthalmology, Otorhinolaryngology and Physiotherapy, Facultad de Medicina, Universidad de Valladolid, Valladolid, Spain Purpose: The objective of this study was to characterize the evolution of ocular pain after advanced surface ablation (ASA to improve strategies in postoperative pain management.Methods: This was a multicenter, prospective, descriptive, cohort study. The inclusion criteria were healthy individuals ≥18 years old receiving bilateral alcohol-assisted surface ablation with epithelial removal. Pain intensity was evaluated with the visual analog scale (VAS and the numeric pain rating scale before and after surgery. Comorbidities (photophobia, burning, tearing, and foreign body sensation and Hospital Anxiety and Depression (HAD questionnaire were evaluated before and at 6 hours after surgery. Postoperative treatments included cold patch, topical cold antibiotics, topical steroids, and benzodiazepines.Results: Thirty-two consecutive patients having similar profiles of postoperative pain evolution were included. At 0.5 hour after ASA, the pain score by VAS was 37±20 mm, and the maximum pain, 61±31 mm, occurred at 24 hours. Afterward, it decreased progressively until 72 hours after surgery (19±20 mm. Most patients (81% scored >60 mm, and

  7. Few promising multivariable prognostic models exist for recovery of people with non-specific neck pain in musculoskeletal primary care: a systematic review.

    Science.gov (United States)

    Wingbermühle, Roel W; van Trijffel, Emiel; Nelissen, Paul M; Koes, Bart; Verhagen, Arianne P

    2018-01-01

    Which multivariable prognostic model(s) for recovery in people with neck pain can be used in primary care? Systematic review of studies evaluating multivariable prognostic models. People with non-specific neck pain presenting at primary care. Baseline characteristics of the participants. Recovery measured as pain reduction, reduced disability, or perceived recovery at short-term and long-term follow-up. Fifty-three publications were included, of which 46 were derivation studies, four were validation studies, and three concerned combined studies. The derivation studies presented 99 multivariate models, all of which were at high risk of bias. Three externally validated models generated usable models in low risk of bias studies. One predicted recovery in non-specific neck pain, while two concerned participants with whiplash-associated disorders (WAD). Discriminative ability of the non-specific neck pain model was area under the curve (AUC) 0.65 (95% CI 0.59 to 0.71). For the first WAD model, discriminative ability was AUC 0.85 (95% CI 0.79 to 0.91). For the second WAD model, specificity was 99% (95% CI 93 to 100) and sensitivity was 44% (95% CI 23 to 65) for prediction of non-recovery, and 86% (95% CI 73 to 94) and 55% (95% CI 41 to 69) for prediction of recovery, respectively. Initial Neck Disability Index scores and age were identified as consistent prognostic factors in these three models. Three externally validated models were found to be usable and to have low risk of bias, of which two showed acceptable discriminative properties for predicting recovery in people with neck pain. These three models need further validation and evaluation of their clinical impact before their broad clinical use can be advocated. PROSPERO CRD42016042204. [Wingbermühle RW, van Trijffel E, Nelissen PM, Koes B, Verhagen AP (2018) Few promising multivariable prognostic models exist for recovery of people with non-specific neck pain in musculoskeletal primary care: a systematic review

  8. Efficacy of kilohertz-frequency and conventional spinal cord stimulation in rat models of different pain conditions.

    Science.gov (United States)

    Song, Zhiyang; Viisanen, Hanna; Meyerson, Björn A; Pertovaara, Antti; Linderoth, Bengt

    2014-04-01

    The aim was to compare the effects of high-frequency spinal cord stimulation (HF-SCS) at subparesthetic intensity with conventional SCS in rat models of different types of pain. In addition, microrecordings of afferent activity in the dorsal columns during both types of SCS were performed to elucidate their mode of action. Miniature SCS electrodes were implanted in all rats. One group was submitted to the spared nerve injury procedure (SNI) and another to inflammatory pain after carrageenan injection into a hind paw. All animals were tested for hypersensitivity to normally innocuous tactile and thermal stimuli. One group of normal healthy rats was submitted to acute nociceptive (pinch, heat) pain. Microrecording of afferent activity in the gracile nucleus (GN) was performed in a group of nerve-lesioned rats responding to conventional SCS. HF-SCS at 500, 1,000, or 10,000 Hz at subparesthetic amplitudes produced similar reductions in hypersensitivity due to nerve lesion as did conventional SCS at 50 Hz. HF-SCS showed no effect on thermal pain. A trial to rescue non-responders to conventional SCS using HF-SCS was not successful. There were no effects either of conventional or of HF-SCS on acute or inflammatory pain. Conventional SCS produced massive activation in the GN but no activation during HF-SCS, though normal peripherally evoked afferent activity remained. Conventional SCS proved equally effective to HF-SCS in various pain models. As no activity is conveyed rostrally in subparesthetic HF-SCS, we hypothesize that its mechanisms of action are primarily segmental. © 2014 International Neuromodulation Society.

  9. Gender differences in pain: do emotions play a role?

    Science.gov (United States)

    Rhudy, Jamie L; Williams, Amy E

    2005-12-01

    affect may be more attuned to pleasurable stimuli in men. However, there is a paucity of research directly addressing this issue; much of the research on this topic has failed to test a comprehensive model of emotion, failed to use adequate manipulation checks, or failed to use within-subject experimental designs that control for intra- and interindividual differences. Therefore, it is concluded that additional research is warranted.

  10. Vitamin D and ferritin correlation with chronic neck pain using standard statistics and a novel artificial neural network prediction model.

    Science.gov (United States)

    Eloqayli, Haytham; Al-Yousef, Ali; Jaradat, Raid

    2018-02-15

    Despite the high prevalence of chronic neck pain, there is limited consensus about the primary etiology, risk factors, diagnostic criteria and therapeutic outcome. Here, we aimed to determine if Ferritin and Vitamin D are modifiable risk factors with chronic neck pain using slandered statistics and artificial intelligence neural network (ANN). Fifty-four patients with chronic neck pain treated between February 2016 and August 2016 in King Abdullah University Hospital and 54 patients age matched controls undergoing outpatient or minor procedures were enrolled. Patients and control demographic parameters, height, weight and single measurement of serum vitamin D, Vitamin B12, ferritin, calcium, phosphorus, zinc were obtained. An ANN prediction model was developed. The statistical analysis reveals that patients with chronic neck pain have significantly lower serum Vitamin D and Ferritin (p-value artificial neural network can be of future benefit in classification and prediction models for chronic neck pain. We hope this initial work will encourage a future larger cohort study addressing vitamin D and iron correction as modifiable factors and the application of artificial intelligence models in clinical practice.

  11. Social redistribution of pain and money.

    Science.gov (United States)

    Story, Giles W; Vlaev, Ivo; Metcalfe, Robert D; Crockett, Molly J; Kurth-Nelson, Zeb; Darzi, Ara; Dolan, Raymond J

    2015-10-30

    People show empathic responses to others' pain, yet how they choose to apportion pain between themselves and others is not well understood. To address this question, we observed choices to reapportion social allocations of painful stimuli and, for comparison, also elicited equivalent choices with money. On average people sought to equalize allocations of both pain and money, in a manner which indicated that inequality carried an increasing marginal cost. Preferences for pain were more altruistic than for money, with several participants assigning more than half the pain to themselves. Our data indicate that, given concern for others, the fundamental principle of diminishing marginal utility motivates spreading costs across individuals. A model incorporating this assumption outperformed existing models of social utility in explaining the data. By implementing selected allocations for real, we also found that while inequality per se did not influence pain perception, altruistic behavior had an intrinsic analgesic effect for the recipient.

  12. Postural hygiene program to prevent low back pain.

    Science.gov (United States)

    Méndez, F J; Gómez-Conesa, A

    2001-06-01

    A quasi-experimental study with 3 x 4 design was performed. To improve the level of knowledge and motor skills and thereby avert the development of painful symptoms. Despite the fact that low back pain affects a high percentage of the population, little research has been carried out to prevent low back pain through health education. The participants in this study were 106 third-grade (9-year-old) students. The program included 11 sessions. The teacher attended the placebo group sessions. No intervention was used with the control group. The level of knowledge and motor skills in the experimental group showed a significant increase immediately after the intervention finished, and at 6- and 12-month intervals after completion of the postural hygiene program (P = 0.00). Some positive changes were generalized to natural situations (P = 0.00). In an independent health check carried out by the local school health services 4 years after application of the postural hygiene program, the results tended slightly to favor the experimental condition over the control conditions (placebo + no intervention). A greater number of the control subjects required medical treatment for low back pain, although this difference was only marginally significant (P = 0.07). The findings from this study support the hypothesis that programs involving practice and motivating strategies impart health knowledge and habits more efficiently than those restricted to the mere transmission of information.

  13. Physical activity, pain responses to heat stimuli, and conditioned pain modulation in postmenopausal women.

    Science.gov (United States)

    Adrian, Amanda L; O'Connor, Patrick J; Ward-Ritacco, Christie L; Evans, Ellen M

    2015-08-01

    Postmenopausal women (PMW) are at high risk for disabling pain and physical inactivity. This study sought to enhance the understanding of relationships between physical activity (PA) and pain among PMW using heat pain sensitivity test and conditioned pain modulation test. We hypothesized that, compared with active women, (i) inactive women would report higher pain intensity and pain unpleasantness ratings; (ii) inactive women in disabling pain would report higher pain intensity and pain unpleasantness at high, but not low, stimulus intensities; and (iii) inactive women would have less modulation. Sixty-eight PMW rated the pain intensity and pain unpleasantness of hot stimuli presented to the thenar eminence of the hand. A subset of 31 women rated the pain intensity of a test stimulus (noxious heat) and a conditioning stimulus (cold water) as part of the conditioned pain modulation task. PA was assessed objectively with accelerometry. Mixed-model analysis of variance (2 × 4 × 2; PA × Temperature × Pain Status) showed that inactive women in disabling pain rated pain unpleasantness higher than active women in disabling pain (F3,192 = 3.526, ∂η = 0.052, P = 0.016). Significantly lower pain unpleasantness ratings were found at the highest stimulus intensity (49°C) only for active women in disabling pain compared with inactive women in disabling pain (t11 = 2.523, P = 0.028). The other hypotheses were not supported. PA is associated with a reduced sensitivity to the unpleasantness of painful high-intensity heat stimuli among women in disabling pain.

  14. The possible role of meditation in myofascial pain syndrome: A new hypothesis

    Directory of Open Access Journals (Sweden)

    Prashanth Panta

    2017-01-01

    Full Text Available Background of Hypothesis: Myofascial pain syndrome (MPS is the most common musculoskeletal pain disorder of the head and neck area. In the past, several theories were put forth to explain its origin and nature, but none proved complete. Myofascial pain responds to changing psychological states and stress, anxiety, lack of sleep, anger, depression and chronic pain are direct contributional factors. Myofascial pain syndrome may be considered as a psychosomatic disorder. There are numerous accepted palliative approaches, but of all, relaxation techniques stand out and initiate healing at the base level. In this article, the connection between mental factors, MPS and meditation are highlighted. Recent literature has shed light on the fundamental role of free radicals in the emergence of myofascial pain. The accumulating free radicals disrupt mitochondrial integrity and function, leading to sustenance and progression of MPS. Meditation on the other hand was shown to reduce free radical load and can result in clinical improvement. 'Mindfulness' is the working principle behind the effect of all meditations, and I emphasize that it can serve as a potential tool to reverse the neuro-architectural, neurobiological and cellular changes that occur in MPS. Conclusions: The findings described in this paper were drawn from studies on myofascial pain, fibromyalgia, similar chronic pain models and most importantly from self experience (experimentation. Till date, no hypothesis is available connecting MPS and meditation. Mechanisms linking MPS and meditation were identified, and this paper can ignite novel research in this direction.

  15. Central Sensitization and Neuropathic Features of Ongoing Pain in a Rat Model of Advanced Osteoarthritis.

    Science.gov (United States)

    Havelin, Joshua; Imbert, Ian; Cormier, Jennifer; Allen, Joshua; Porreca, Frank; King, Tamara

    2016-03-01

    Osteoarthritis (OA) pain is most commonly characterized by movement-triggered joint pain. However, in advanced disease, OA pain becomes persistent, ongoing and resistant to treatment with nonsteroidal anti-inflammatory drugs (NSAIDs). The mechanisms underlying ongoing pain in advanced OA are poorly understood. We recently showed that intra-articular (i.a.) injection of monosodium iodoacetate (MIA) into the rat knee joint produces concentration-dependent outcomes. Thus, a low dose of i.a. MIA produces NSAID-sensitive weight asymmetry without evidence of ongoing pain and a high i.a. MIA dose produces weight asymmetry and NSAID-resistant ongoing pain. In the present study, palpation of the ipsilateral hind limb of rats treated 14 days previously with high, but not low, doses of i.a. MIA produced expression of the early oncogene, FOS, in the spinal dorsal horn. Inactivation of descending pain facilitatory pathways using a microinjection of lidocaine within the rostral ventromedial medulla induced conditioned place preference selectively in rats treated with the high dose of MIA. Conditioned place preference to intra-articular lidocaine was blocked by pretreatment with duloxetine (30 mg/kg, intraperitoneally at -30 minutes). These observations are consistent with the likelihood of a neuropathic component of OA that elicits ongoing, NSAID-resistant pain and central sensitization that is mediated, in part, by descending modulatory mechanisms. This model provides a basis for exploration of underlying mechanisms promoting neuropathic components of OA pain and for the identification of mechanisms that might guide drug discovery for treatment of advanced OA pain without the need for joint replacement. Difficulty in managing advanced OA pain often results in joint replacement therapy in these patients. Improved understanding of mechanisms driving NSAID-resistant ongoing OA pain might facilitate development of alternatives to joint replacement therapy. Our findings suggest

  16. PHYSIOLOGICAL MECHANISMS OF POLARIZED LIGHT INFLUENCE ON PAIN

    OpenAIRE

    S. О. Gulyar; Z. А. Tamarova

    2016-01-01

    There are presented experimental evidences of BIOPTRON device polarized light influence on the acupuncture points and pain locus. It is proved that PILER-light can induce analgesia which depends on the choice of the application zone, exposure and nature of pain (tonic, acute or visceral). Analgesic response has systemic character and is accompanied by participation of opioidergic nociceptive system

  17. Cancer Health Empowerment for Living without Pain (Ca-HELP: study design and rationale for a tailored education and coaching intervention to enhance care of cancer-related pain

    Directory of Open Access Journals (Sweden)

    Slee Christina

    2009-09-01

    Full Text Available Abstract Background Cancer-related pain is common and under-treated. This article describes a study designed to test the effectiveness of a theory-driven, patient-centered coaching intervention to improve cancer pain processes and outcomes. Methods/Design The Cancer Health Empowerment for Living without Pain (Ca-HELP Study is an American Cancer Society sponsored randomized trial conducted in Sacramento, California. A total of 265 cancer patients with at least moderate pain severity (Worst Pain Numerical Analog Score >=4 out of 10 or pain-related impairment (Likert score >= 3 out of 5 were randomly assigned to receive tailored education and coaching (TEC or educationally-enhanced usual care (EUC; 258 received at least one follow-up assessment. The TEC intervention is based on social-cognitive theory and consists of 6 components (assess, correct, teach, prepare, rehearse, portray. Both interventions were delivered over approximately 30 minutes just prior to a scheduled oncology visit. The majority of visits (56% were audio-recorded for later communication coding. Follow-up data including outcomes related to pain severity and impairment, self-efficacy for pain control and for patient-physician communication, functional status and well-being, and anxiety were collected at 2, 6, and 12 weeks. Discussion Building on social cognitive theory and pilot work, this study aims to test the hypothesis that a brief, tailored patient activation intervention will promote better cancer pain care and outcomes. Analyses will focus on the effects of the experimental intervention on pain severity and impairment (primary outcomes; self-efficacy and quality of life (secondary outcomes; and relationships among processes and outcomes of cancer pain care. If this model of coaching by lay health educators proves successful, it could potentially be implemented widely at modest cost. Trial Registration [Clinical Trials Identifier: NCT00283166

  18. Development and validation of an animal model of prostate inflammation-induced chronic pelvic pain: evaluating from inflammation of the prostate to pain behavioral modifications.

    Directory of Open Access Journals (Sweden)

    Feng Zeng

    Full Text Available BACKGROUND: Chronic prostatitis/Chronic pelvic pain syndrome (CP/CPPS is the most common type of prostatitis. Due to the lack of a suitable animal model partly, the pathogenesis for this condition is obscure. In the current study we developed and validated an animal model for nonbacterial prostatitis and prostate inflammation-induced chronic pelvic pain in rats with the use of intraprostatic injection of λ-carrageenan. METHODS: Male Sprague-Dawley rats weighing 250-350 g were used for the experiments. After intraprostatic injection of 3% λ-carrageenan, at different time points(after 24 h, 7 d, 14 d and 30 d of injection, radiant heat and von Frey filaments were applied to the scrotum of rats to measure the heat and mechanical thresholds respectively. Then the prostate was removed for histology, and cyclooxygenase (COX 2 protein expression was determined by Western-blot. Evans blue(50 mg/kg was also injected intravenously to assess for plasma protein extravasation at different time points after injection of λ-carrageenan. RESULTS: Compared to control group, inflamed animals showed a significant reduction in mechanical threshold (mechanical allodynia at 24 h and 7d(p = 0.022,0.046, respectively, and a significant reduction in heat threshold (thermal hyperalgesia at 24 h, 7d and 14 d(p = 0.014, 0.018, 0.002, respectively in the scrotal skin. Significant increase of inflammatory cell accumulation, COX2 expression and Evans blue extravasation were observed at 24 h, 7d and 14 d after injection. CONCLUSIONS: Intraprostatic λ-carrageenan injection induced neurogenic prostatitis and prostate inflammation pain, which lasted at least 2 weeks. The current model is expected to be a valuable preclinical tool to study the neurobiological mechanisms of male chronic pelvic pain.

  19. Mechanisms of Dorsal Root Ganglion Stimulation in Pain Suppression: A Computational Modeling Analysis.

    Science.gov (United States)

    Kent, Alexander R; Min, Xiaoyi; Hogan, Quinn H; Kramer, Jeffery M

    2018-04-01

    The mechanisms of dorsal root ganglion (DRG) stimulation for chronic pain remain unclear. The objective of this work was to explore the neurophysiological effects of DRG stimulation using computational modeling. Electrical fields produced during DRG stimulation were calculated with finite element models, and were coupled to a validated biophysical model of a C-type primary sensory neuron. Intrinsic neuronal activity was introduced as a 4 Hz afferent signal or somatic ectopic firing. The transmembrane potential was measured along the neuron to determine the effect of stimulation on intrinsic activity across stimulation parameters, cell location/orientation, and membrane properties. The model was validated by showing close correspondence in action potential (AP) characteristics and firing patterns when compared to experimental measurements. Subsequently, the model output demonstrated that T-junction filtering was amplified with DRG stimulation, thereby blocking afferent signaling, with cathodic stimulation at amplitudes of 2.8-5.5 × stimulation threshold and frequencies above 2 Hz. This amplified filtering was dependent on the presence of calcium and calcium-dependent small-conductance potassium channels, which produced a hyperpolarization offset in the soma, stem, and T-junction with repeated somatic APs during stimulation. Additionally, DRG stimulation suppressed somatic ectopic activity by hyperpolarizing the soma with cathodic or anodic stimulation at amplitudes of 3-11 × threshold and frequencies above 2 Hz. These effects were dependent on the stem axon being relatively close to and oriented toward a stimulating contact. These results align with the working hypotheses on the mechanisms of DRG stimulation, and indicate the importance of stimulation amplitude, polarity, and cell location/orientation on neuronal responses. © 2018 International Neuromodulation Society.

  20. Differential effects of subcutaneous electrical stimulation (SQS) and transcutaneous electrical nerve stimulation (TENS) in rodent models of chronic neuropathic or inflammatory pain.

    Science.gov (United States)

    Vera-Portocarrero, Louis P; Cordero, Toni; Billstrom, Tina; Swearingen, Kim; Wacnik, Paul W; Johanek, Lisa M

    2013-01-01

    Electrical stimulation has been used for many years for the treatment of pain. Present-day research demonstrates that stimulation targets and parameters impact the induction of specific pain-modulating mechanisms. New targets are increasingly being investigated clinically, but the scientific rationale for a particular target is often not well established. This present study compares the behavioral effects of targeting peripheral axons by electrode placement in the subcutaneous space vs. electrode placement on the surface of the skin in a rodent model. Rodent models of inflammatory and neuropathic pain were used to investigate subcutaneous electrical stimulation (SQS) vs. transcutaneous electrical nerve stimulation (TENS). Electrical parameters and relative location of the leads were held constant under each condition. SQS had cumulative antihypersensitivity effects in both inflammatory and neuropathic pain rodent models, with significant inhibition of mechanical hypersensitivity observed on days 3-4 of treatment. In contrast, reduction of thermal hyperalgesia in the inflammatory model was observed during the first four days of treatment with SQS, and reduction of cold allodynia in the neuropathic pain model was seen only on the first day with SQS. TENS was effective in the inflammation model, and in agreement with previous studies, tolerance developed to the antihypersensitivity effects of TENS. With the exception of a reversal of cold hypersensitivity on day 1 of testing, TENS did not reveal significant analgesic effects in the neuropathic pain rodent model. The results presented show that TENS and SQS have different effects that could point to unique biologic mechanisms underlying the analgesic effect of each therapy. Furthermore, this study is the first to demonstrate in an animal model that SQS attenuates neuropathic and inflammatory-induced pain behaviors. © 2013 Medtronic, Inc.