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Sample records for rat masseter muscle

  1. An animal model for human masseter muscle: histochemical characterization of mouse, rat, rabbit, cat, dog, pig, and cow masseter muscle

    DEFF Research Database (Denmark)

    Tuxen, A; Kirkeby, S

    1990-01-01

    .4, type IM fibers react moderately, and type II fibers react strongly. Rat and mouse masseter muscles contained type II fibers only, as did some rabbit masseter muscles, whereas other rabbit masseter muscles possessed equal amounts of type I and II fibers. Cat and dog masseter muscles possessed both type...

  2. Nerve growth factor alters the sensitivity of rat masseter muscle mechanoreceptors to NMDA receptor activation.

    Science.gov (United States)

    Wong, Hayes; Dong, Xu-Dong; Cairns, Brian E

    2014-11-01

    Intramuscular injection of nerve growth factor (NGF) into rat masseter muscle induces a local mechanical sensitization that is greater in female than in male rats. The duration of NGF-induced sensitization in male and female rats was associated with an increase in peripheral N-methyl-d-aspartate (NMDA) receptor expression by masseter muscle afferent fibers that began 3 days postinjection. Here, we investigated the functional consequences of increased NMDA expression on the response properties of masseter muscle mechanoreceptors. In vivo extracellular single-unit electrophysiological recordings of trigeminal ganglion neurons innervating the masseter muscle were performed in anesthetized rats 3 days after NGF injection (25 μg/ml, 10 μl) into the masseter muscle. Mechanical activation threshold was assessed before and after intramuscular injection of NMDA. NMDA injection induced mechanical sensitization in both sexes that was increased significantly following NGF injection in the male rats but not in the female rats. However, in female but not male rats, further examination found that preadministration of NGF induced a greater sensitization in slow Aδ-fibers (2-7 m/s) than fast Aδ-fibers (7-12 m/s). This suggests that preadministration of NGF had a different effect on slowly conducting mechanoreceptors in the female rats compared with the male rats. Although previous studies have found an association between estrogenic tone and NMDA activity, no correlation was observed between NMDA-evoked mechanical sensitization and plasma estrogen level. This study suggests NGF alters NMDA-induced mechanical sensitization in the peripheral endings of masseter mechanoreceptors in a sexually dimorphic manner.

  3. Effect of triiodothyronine on the maxilla and masseter muscles of the rat stomatognathic system

    Directory of Open Access Journals (Sweden)

    M.V. Mariúba

    2011-07-01

    Full Text Available The maxilla and masseter muscles are components of the stomatognathic system involved in chewing, which is frequently affected by physical forces such as gravity, and by dental, orthodontic and orthopedic procedures. Thyroid hormones (TH are known to regulate the expression of genes that control bone mass and the oxidative properties of muscles; however, little is known about the effects of TH on the stomatognathic system. This study investigated this issue by evaluating: i osteoprotegerin (OPG and osteopontine (OPN mRNA expression in the maxilla and ii myoglobin (Mb mRNA and protein expression, as well as fiber composition of the masseter. Male Wistar rats (~250 g were divided into thyroidectomized (Tx and sham-operated (SO groups (N = 24/group treated with T3 or saline (0.9% for 15 days. Thyroidectomy increased OPG (~40% and OPN (~75% mRNA expression, while T3 treatment reduced OPG (~40% and OPN (~75% in Tx, and both (~50% in SO rats. Masseter Mb mRNA expression and fiber type composition remained unchanged, despite the induction of hypo- and hyperthyroidism. However, Mb content was decreased in Tx rats even after T3 treatment. Since OPG and OPN are key proteins involved in the osteoclastogenesis inhibition and bone mineralization, respectively, and that Mb functions as a muscle store of O2 allowing muscles to be more resistant to fatigue, the present data indicate that TH also interfere with maxilla remodeling and the oxidative properties of the masseter, influencing the function of the stomatognathic system, which may require attention during dental, orthodontic and orthopedic procedures in patients with thyroid diseases.

  4. Chronic sleep deprivation alters the myosin heavy chain isoforms in the masseter muscle in rats.

    Science.gov (United States)

    Cao, Ruihua; Huang, Fei; Wang, Peihuan; Chen, Chen; Zhu, Guoxiong; Chen, Lei; Wu, Gaoyi

    2015-05-01

    To investigate the changes in myosin heavy chain (MyHC) isoforms of rat masseter muscle fibres caused by chronic sleep deprivation and a possible link with the pathogenesis of disorders of the temporomandibular joint (TMJ). A total of 180 male rats were randomly divided into three groups (n=60 in each): cage controls, large platform controls, and chronic sleep deprivation group. Each group was further divided into three subgroups with different observation periods (7, 14, and 21 days). We investigated he expression of MyHC isoforms in masseter muscle fibres by real-time quantitative polymerase chain reaction (PCR), Western blotting, and immunohistochemical staining. In rats with chronic sleep deprivation there was increased MyHC-I expression in layers of both shallow and deep muscles at 7 and 21 days compared with the control groups, whereas sleep deprivation was associated with significantly decreased MyHC-II expression. At 21 days, there were no differences in MyHC-I or MyHC-II expression between the groups and there were no differences between the two control groups at any time point. These findings suggest that chronic sleep deprivation alters the expression of MyHC isoforms, which may contribute to the pathogenesis of disorders of the TMJ.

  5. Effects of the unilateral removal and dissection of the masseter muscle on the facial growth of young rats

    Directory of Open Access Journals (Sweden)

    Lucimar Rodrigues

    2009-03-01

    Full Text Available This study analyzed the effects of the unilateral removal and dissection of the masseter muscle on the facial growth of young rats. A total of 30 one-month-old Wistar rats were used. Unilateral complete removal of the masseter muscle was performed in the removal group, and detachment followed by repositioning of the masseter muscle was performed in the dissection group, while only surgical access was performed in the sham-operated group. The animals were sacrificed at three months of age. Axial radiographic projections of the skulls and lateral projections of the hemimandibles were taken. Cephalometric evaluations were made and the values obtained were submitted to statistical analyses. In the removal group, there were contour alterations of the angular process, and a significant homolateral difference in the length of the maxilla and a significant bilateral difference in the height of the mandibular body and the length of the mandible were observed. Comparison among groups revealed significance only in the removal group. It was concluded that the experimental removal of the masseter muscle during the growing period in rats induced atrophic changes in the angular process, as well as asymmetry of the maxilla and shortening of the whole mandible.

  6. Comparative anatomic study of mandibular growth in rats after bilateral resections of superficial masseter, posterior temporal, and anterior digastric muscles.

    Science.gov (United States)

    Lifshitz, J

    1976-01-01

    Bilateral resections of the superficial masseter, posterior temporal, and anterior digastric muscles of rats were done to determine their effects on mandibular growth. The macroscopic findings support the functional matrix theory of mandibular growth. The analysis of body weight and the statistical two-way analysis of variance done suggest that malnutrition was the main factor that caused the mandibles of rats in the experimental groups of remain undersized.

  7. Changes following denervation to the masseter muscle

    Institute of Scientific and Technical Information of China (English)

    Lei Zhang

    2008-01-01

    BACKGROUND: Masseter muscle nerve is often injured in mandible osteotomy. What changes in food intake and masseter muscle will be brought after masseter muscle nerve injury?OBJECTIVE: This study was designed to selectively establish animal models of denervated masseter muscle and investigate the effects of severing masseter muscular nerve on masseter muscle and animal's food intake. DESIGN, TIME AND SETTING: A randomized controlled animal experiment was performed at the Laboratory Animal Center, Nanfang Hospital, Southern Medical University from September to November 2005. MATERIALS: A total of 50 healthy, adult, SPF-grade, New Zealand rabbits, of both genders, were used to develop an animal model of selectively denervated masseter muscle.METHODS: Five rabbits were randomly selected as normal controls. According to various mutilation methods, the remaining animals were randomly divided into 3 experimental groups, with 15 rabbits in each group: masseter muscular neural stem denervated, masseter muscular neural superior branch-denervated, and masseter muscular neural inferior branch-denervated groups. Self-control comparison was performed on each animal. The right masseter muscle served as the experimental side, and the left masseter muscle served as the control side. In each group, 3 time points (2, 8, and 24 weeks post-surgery) were allotted for observation. MAIN OUTCOME MEASURES: At the pre-set time points, masseter muscular thickness was measured with a Logic 500 color Doppler ultrasonic diagnostic apparatus. Masseter muscle tissue was resected for hematoxylin eosin staining. Masseter muscular fiber diameter and area were measured with an optical microscope. Masseter muscle tissue was sectioned and nicotinamide adenine dinucleotide tetrazolium oxidoreductase (NADH-TR) and adenosine triphosphatase staining were performed. Following staining, the sections were quantitatively analyzed using an IBAS200 image analyzer.RESULTS: Post-surgery food intake: No abnormal

  8. Spatiotemporal Profiles of Proprioception Processed by the Masseter Muscle Spindles in Rat Cerebral Cortex: An Optical Imaging Study

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    Fujita, Satoshi; Kaneko, Mari; Nakamura, Hiroko; Kobayashi, Masayuki

    2017-01-01

    Muscle spindles in the jaw-closing muscles, which are innervated by trigeminal mesencephalic neurons (MesV neurons), control the strength of occlusion and the position of the mandible. The mechanisms underlying cortical processing of proprioceptive information are critical to understanding how sensory information from the masticatory muscles regulates orofacial motor function. However, these mechanisms are mostly unknown. The present study aimed to identify the regions that process proprioception of the jaw-closing muscles using in vivo optical imaging with a voltage-sensitive dye in rats under urethane anesthesia. First, jaw opening that was produced by mechanically pulling down the mandible evoked an optical response, which reflects neural excitation, in two cortical regions: the most rostroventral part of the primary somatosensory cortex (S1) and the border between the ventral part of the secondary somatosensory cortex (S2) and the insular oral region (IOR). The kinetics of the optical signal, including the latency, amplitude, rise time, decay time and half duration, in the S1 region for the response with the largest amplitude were comparable to those in the region with the largest response in S2/IOR. Second, we visualized the regions responding to electrical stimulation of the masseter nerve, which activates both motor efferent fibers and somatosensory afferent fibers, including those that transmit nociceptive and proprioceptive information. Masseter nerve stimulation initially excited the rostral part of the S2/IOR region, and an adjacent region responded to jaw opening. The caudal part of the region showing the maximum response overlapped with the region responding to jaw opening, whereas the rostral part overlapped with the region responding to electrical stimulation of the maxillary and mandibular molar pulps. These findings suggest that proprioception of the masseter is processed in S1 and S2/IOR. Other sensory information, such as nociception, is

  9. Esterase profile of human masseter muscle

    DEFF Research Database (Denmark)

    Kirkeby, S; Moe, D; Vilmann, H

    1988-01-01

    The esterase profile of fresh human masseter muscle was investigated by use of histochemistry and electrophoresis. The histochemical methods included reactions for alpha-naphthyl esterase, myofibrillar ATPase, reverse myofibrillar ATPase and succinic dehydrogenase. In frozen sections of the muscl...

  10. Effects on craniofacial growth and development of unilateral botulinum neurotoxin injection into the masseter muscle.

    Science.gov (United States)

    Tsai, Chi-Yang; Chiu, Wan Chi; Liao, Yi-Hsuan; Tsai, Chih-Mong

    2009-02-01

    The effects of botulinum neurotoxin type A (BoNT/A) on masseter muscles, when injected for cosmetic purposes (volumetric reduction) or treatment of excessive muscle activity (bruxism), have been investigated. However, the full anatomic effects of treatment are not known, particularly with respect to the mandible and relevant anthropometric measurements. The intent of this study was to use unilaterial BoNT/A injections to induce localized masseter atrophy and paresis and then to measure the effects of muscle influence on craniofacial growth and development. Growing male Wistar rats, 30 days old, were studied. The experimental group consisted of 8 rats. One side of the masseter muscle was injected with BoNT/A and the other side of the masseter muscle was injected with saline. The side with BoNT/A belonged to 1 group and the side with saline was the sham group. Three rats without injections was the control. After 45 days, the masseter muscles were dissected and weighed. Dry skulls were prepared, and anthropometric measurements determined. One-way ANOVA showed that the animals maintained their weight in both groups; however, the muscles injected with BoNT/A were smaller than the sham or control muscles. Anthropometric measurements of the bony structures attached to the masseter muscle showed a significant treatment effect. After localized masseter muscle atrophy induced by BoNT/A injection, alterations of craniofacial bone growth and development were seen. The results agree with the functional matrix theory that soft tissues regulate bone growth.

  11. Masseter and medial pterygoid muscle hypertrophy.

    Science.gov (United States)

    Guruprasad, R; Rishi, Sudhirkumar; Nair, Preeti P; Thomas, Shaji

    2011-09-26

    Hypertrophy refers to an enlargement caused by an increase in the size but not in the number of cells. Generalised masticatory muscle hypertrophy may affect the temporalis muscle, masseters and medial pterygoids in a variety of combinations. Masseteric hypertrophy may present as either unilateral or bilateral painless swelling of unknown origin in the region of angle of mandible. It is a relatively rare condition and presents a diagnostic dilemma. While the history and clinical examination are important in differentiating this benign condition from parotid or dental pathology, they cannot necessarily exclude rare malignant lesion within the muscle. Advanced imaging modalities like CT and MRI are essential to confirm the diagnosis. Here the authors are reporting a unique case of masseter muscle hypertrophy along with medial pterygoid hypertrophy which was missed clinically but confirmed using CT and MRI.

  12. Masseter and medial pterygoid muscle hypertrophy

    OpenAIRE

    R, Guruprasad; Rishi, Sudhirkumar; Nair, Preeti P; Thomas, Shaji

    2011-01-01

    Hypertrophy refers to an enlargement caused by an increase in the size but not in the number of cells. Generalised masticatory muscle hypertrophy may affect the temporalis muscle, masseters and medial pterygoids in a variety of combinations. Masseteric hypertrophy may present as either unilateral or bilateral painless swelling of unknown origin in the region of angle of mandible. It is a relatively rare condition and presents a diagnostic dilemma. While the history and clinical examination ar...

  13. GABAB receptors in the NTS mediate the inhibitory effect of trigeminal nociceptive inputs on parasympathetic reflex vasodilation in the rat masseter muscle.

    Science.gov (United States)

    Ishii, Hisayoshi; Izumi, Hiroshi

    2012-03-15

    The present study was designed to examine whether trigeminal nociceptive inputs are involved in the modulation of parasympathetic reflex vasodilation in the jaw muscles. This was accomplished by investigating the effects of noxious stimulation to the orofacial area with capsaicin, and by microinjecting GABA(A) and GABA(B) receptor agonists or antagonists into the nucleus of the solitary tract (NTS), on masseter hemodynamics in urethane-anesthetized rats. Electrical stimulation of the central cut end of the cervical vagus nerve (cVN) in sympathectomized animals bilaterally increased blood flow in the masseter muscle (MBF). Increases in MBF evoked by cVN stimulation were markedly reduced following injection of capsaicin into the anterior tongue in the distribution of the lingual nerve or lower lip, but not when injected into the skin of the dorsum of the foot. Intravenous administration of either phentolamine or propranolol had no effect on the inhibitory effects of capsaicin injection on the increases of MBF evoked by cVN stimulation, which were largely abolished by microinjecting the GABA(B) receptor agonist baclofen into the NTS. Microinjection of the GABA(B) receptor antagonist CGP-35348 into the NTS markedly attenuated the capsaicin-induced inhibition of MBF increase evoked by cVN stimulation, while microinjection of the GABA(A) receptor antagonist bicuculline did not. Our results indicate that trigeminal nociceptive inputs inhibit vagal-parasympathetic reflex vasodilation in the masseter muscle and suggest that the activation of GABA(B) rather than GABA(A) receptors underlies the observed inhibition in the NTS.

  14. Bimaxillary protrusion with masseter muscle hypertrophy treated with titanium screw anchorage and masseter surgical reduction.

    Science.gov (United States)

    Hashimoto, Takashi; Kuroda, Shingo; Kamioka, Hiroshi; Mishima, Katsuaki; Sugahara, Toshio; Takano-Yamamoto, Teruko

    2009-04-01

    This case report describes the treatment of a patient with bimaxillary protrusion and masseter muscle hypertrophy. At age 21 years 7 months, this woman had temporomandibular disorder (TMD) symptoms, severe bimaxillary protrusion, and a prominent mandibular angle with facial asymmetry. After an attempt to alleviate the TMD symptoms with occlusal splint stabilization, portions of the masseter muscle and the mandible were surgically removed. Titanium screws were placed bilaterally in both arches, and a retraction force was applied. After active treatment for 38 months, the convexity of the facial profile with lip protrusion was improved remarkably, and good occlusion was achieved. The prominent mandibular angle with facial asymmetry was improved as a result of the surgical reduction of the masseter muscle and the modeling ostectomy near the masseteric tuberosity. The TMD symptoms disappeared, and the jaw movement pattern became normal. Therefore, our results suggest that this combination treatment would be useful for masseter muscle hypertrophy for morphologic and functional problems.

  15. Protective Effects of Clenbuterol against Dexamethasone-Induced Masseter Muscle Atrophy and Myosin Heavy Chain Transition.

    Science.gov (United States)

    Umeki, Daisuke; Ohnuki, Yoshiki; Mototani, Yasumasa; Shiozawa, Kouichi; Suita, Kenji; Fujita, Takayuki; Nakamura, Yoshiki; Saeki, Yasutake; Okumura, Satoshi

    2015-01-01

    Glucocorticoid has a direct catabolic effect on skeletal muscle, leading to muscle atrophy, but no effective pharmacotherapy is available. We reported that clenbuterol (CB) induced masseter muscle hypertrophy and slow-to-fast myosin heavy chain (MHC) isoform transition through direct muscle β2-adrenergic receptor stimulation. Thus, we hypothesized that CB would antagonize glucocorticoid (dexamethasone; DEX)-induced muscle atrophy and fast-to-slow MHC isoform transition. We examined the effect of CB on DEX-induced masseter muscle atrophy by measuring masseter muscle weight, fiber diameter, cross-sectional area, and myosin heavy chain (MHC) composition. To elucidate the mechanisms involved, we used immunoblotting to study the effects of CB on muscle hypertrophic signaling (insulin growth factor 1 (IGF1) expression, Akt/mammalian target of rapamycin (mTOR) pathway, and calcineurin pathway) and atrophic signaling (Akt/Forkhead box-O (FOXO) pathway and myostatin expression) in masseter muscle of rats treated with DEX and/or CB. Masseter muscle weight in the DEX-treated group was significantly lower than that in the Control group, as expected, but co-treatment with CB suppressed the DEX-induced masseter muscle atrophy, concomitantly with inhibition of fast-to-slow MHC isoforms transition. Activation of the Akt/mTOR pathway in masseter muscle of the DEX-treated group was significantly inhibited compared to that of the Control group, and CB suppressed this inhibition. DEX also suppressed expression of IGF1 (positive regulator of muscle growth), and CB attenuated this inhibition. Myostatin protein expression was unchanged. CB had no effect on activation of the Akt/FOXO pathway. These results indicate that CB antagonizes DEX-induced muscle atrophy and fast-to-slow MHC isoform transition via modulation of Akt/mTOR activity and IGF1 expression. CB might be a useful pharmacological agent for treatment of glucocorticoid-induced muscle atrophy.

  16. Long lasting pain hypersensitivity following ligation of the tendon of the masseter muscle in rats: A model of myogenic orofacial pain

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    Dubner Ronald

    2010-07-01

    Full Text Available Abstract Background A major subgroup of patients with temporomandibular joint (TMJ disorders have masticatory muscle hypersensitivity. To study myofacial temporomandibular pain, a number of preclinical models have been developed to induce myogenic pain of the masseter muscle, one of the four muscles involved in mastication. The currently used models, however, generate pain that decreases over time and only lasts from hours to weeks and hence are not suitable for studying chronicity of the myogenic pain in TMJ disorders. Here we report a model of constant myogenic orofacial pain that lasts for months. Results The model involves unilateral ligation of the tendon of the anterior superficial part of the rat masseter muscle (TASM. The ligation of the TASM was achieved with two chromic gut (4.0 ligatures via an intraoral approach. Nocifensive behavior of the rat was assessed by probing the skin site above the TASM with a series of von Frey filaments. The response frequencies were determined and an EF50 value, defined as the von Frey filament force that produces a 50% response frequency, was derived and used as a measure of mechanical sensitivity. Following TASM ligation, the EF50 of the injured side was significantly reduced and maintained throughout the 8-week observation period, suggesting the presence of mechanical hyperalgesia/allodynia. In sham-operated rats, the EF50 of the injured side was transiently reduced for about a week, likely due to injury produced by the surgery. Somatotopically relevant Fos protein expression was indentified in the subnucleus caudalis of the spinal trigeminal sensory complex. In the same region, persistent upregulation of NMDA receptor NR1 phosphorylation and protein expression and increased expression of glial markers glial fibrillary acidic protein (astroglia and CD11b (microglia were found. Morphine (0.4-8 mg/kg, s.c. and duloxetine (0.4-20 mg/kg, i.p., a selective serotonin-norepinephrine reuptake inhibitor

  17. Reduced masticatory function is related to lower satellite cell numbers in masseter muscle.

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    Kuijpers, M A R; Grefte, S; Bronkhorst, E M; Carels, C E L; Kiliaridis, S; Von den Hoff, J W

    2014-06-01

    The physiology of masseter muscles is known to change in response to functional demands, but the effect on the satellite cell (SC) population is not known. In this study, the hypothesis is tested that a decreased functional demand of the masseter muscle causes a reduction of SCs. To this end, twelve 5-week-old male Sprague-Dawley rats were put on a soft diet (SD, n = 6) or a hard diet (HD, n = 6) and sacrificed after 14 days. Paraffin sections of the superficial masseter and the m. digastricus (control muscle) were stained with haematoxylin and eosin for tissue survey and with anti-myosin heavy chain (MHC) for slow and fast fibres. Frozen sections of both muscles were double-stained for collagen type IV and Pax7. Slow MHC fibres were equally distributed in the m. digastricus but only localized in a small area of the m. masseter. No differences between HD or SD for the m. digastricus were found. The m. masseter had more SCs per fibre in HD than in SD (0.093 ± 0.007 and 0.081 ± 0.008, respectively; P = 0.027). The m. masseter had more fibres per surface area than the m. digastricus in rats with an SD group (758.1 ± 101.6 and 568.4 ± 85.6, P = 0.047) and a HD group (737.7 ± 32.6 and 592.2 ± 82.2; P = 0.007). The m. digastricus had more SCs per fibre than the m. masseter in the SD group (0.094 ± 0.01 and 0.081 ± 0.008; P = 0.039). These results suggest that reduced masseter muscle function is related to a lower number of SCs. Reduced muscle function might decrease microdamage and hence the requirement of SCs in the muscle fibres.

  18. Functional Compartmentalization of the Human Superficial Masseter Muscle

    OpenAIRE

    Guzmán-Venegas, Rodrigo A.; Biotti Picand, Jorge L.; Francisco J Berral de la Rosa

    2015-01-01

    Some muscles have demonstrated a differential recruitment of their motor units in relation to their location and the nature of the motor task performed; this involves functional compartmentalization. There is little evidence that demonstrates the presence of a compartmentalization of the superficial masseter muscle during biting. The aim of this study was to describe the topographic distribution of the activity of the superficial masseter (SM) muscle's motor units using high-density surface e...

  19. Bilateral masseter and internal pterygoid muscle hypertrophy: a diagnostic challenge.

    Science.gov (United States)

    Andreadis, Dimitrios; Stylianou, Florentia; Link-Tsatsouli, Iris; Markopoulos, Anastasios

    2014-01-01

    To describe an unusual case of bilateral masseter and pterygoid muscle hypertrophy. A 53-year-old female patient presented with a bilateral, painless swelling at the parotid areas without improvement after using antibiotics/systemic corticosteroids/nonsteroidal anti-inflammatory agents. Her medical history included thyroid nodules, but no dental/occlusal disorders were observed. The initial differential diagnosis included salivary gland/jaw bone/masseter pathology, but the CT/MRI revealed only an increase in the size of the masseter and pterygoid muscles. The patient was informed of the benign nature of the swelling and was advised to discontinue the use of nonsteroidal anti-inflammatory agents. The bilateral hypertrophy of masseter muscles should be considered in differential diagnosis in cases of unilateral or bilateral swelling of the parotid or lateral mandible area. © 2013 S. Karger AG, Basel.

  20. Peripheral primitive neuroectodermal tumor in masseter muscle.

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    Yazc, Haşmet; Yiğit, Barş; Doğan, Sedat; Sunter, Ahmet Volkan; Behzatoğlu, Kemal

    2013-05-01

    Primitive neuroectodermal tumor is a member of malignant small round cell tumors. These tumors especially originate from the central and autonomous nervous system. However, these tumors may be originated from peripheral tissues and are called peripheral primitive neuroectodermal tumor. A 14-year-old girl attended to the Ear Nose Throat Clinic with the complaint of progressive painless swelling mass for 2 months on the right side of the face. Neck magnetic resonance imaging showed 3.5 × 2.5 × 2-cm isointense mass on T1 and hyperintense on T2 sequences. There was no pathological lymphadenopathy on computed tomographic scan. As a result of mandibular cortical invasion seen on computed tomographic scan, radical surgical excision was decided as surgical treatment. Total parotidectomy with preserving facial nerve and partial mandibulectomy with a 2-cm margin of safety were done, and reconstruction plaque applied to the mandible. Two lymph nodes were seen at the submandibular region. For this reason, prophylactic supraomohyoid neck dissection had also been performed. Pathological assessment proved the diagnosis of PNET, and chemoradiotherapy was planned for the patient.To our knowledge, this is the second reported case in literature. In this present case, peripheral neuroectodermal tumor in the masseter muscle and its diagnosis and treatment process were reported with literature review.

  1. MOTOR UNIT TERRITORIES AND FIBER TYPES IN RABBIT MASSETER MUSCLE

    NARCIS (Netherlands)

    WEIJS, WA; JUCH, PJW; KWA, SHS; KORFAGE, JAM

    1993-01-01

    The myosin heavy chain (MHC) content and spatial distribution of the fibers of 11 motor units (MUs) of the rabbit masseter muscle were determined. The fibers of single MUs were visualized in whole-muscle serial sections by a negative periodic acid/Schiff reaction for glycogen after they had been dep

  2. Dimensions and geometry of the temporomandibular joint and masseter muscles.

    Science.gov (United States)

    Zurowski, R; Gosek, M; Aleksandrowicz, R

    1976-01-01

    The bio-engineering team presents its suggestion of a method for the measurement of the temporomandibular joint and masseter muscles in order to determine the parameters necessary for exact sciences and indispensable for unified and objective cognitive studies. Ten formalin-fixed human cadavers served for the studies. The preparations were prepared by the modified method of anatomical procedure. Linear and angular measurements of temporomandibular joint and masseter muscles were carried out with the use of the three-dimensional Cartesian system of OXYZ coordinates in relation to frontal, sagittal and horizontal planes. The physiological cross-sections of the masseter, temporal, lateral and medial pterygoid muscles were also determined. The collected data make it possible to develop a mathematical three-dimensioned model of the osseo-articulo-muscular system of the mastication organ.

  3. Changes in intramuscular cytokine levels during masseter inflammation in male and female rats

    OpenAIRE

    Niu, Katelyn Y.; Ro, Jin Y.

    2010-01-01

    The present study was conducted to examine cytokine profiles in the masseter muscle before and after complete Freund’s adjuvant (CFA)-induced inflammation and possible sex differences in the cytokine levels. Age matched male and female Sprague Dawley rats were injected with CFA in the mid-region of the masseter muscle. Muscle tissue surrounding the injection site was extracted 6 hrs, 1, 3 and 7 days after the injection to measure TNF-α, IL-1β, IL-6 and IL-4 levels with Luminex multi-analyte p...

  4. THE CAPILLARY PATTERN IN HUMAN MASSETER MUSCLE DURING AGEING

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    Erika Cvetko

    2013-10-01

    Full Text Available The effect of ageing on the capillary network in skeletal muscles has produced conflicting results in both, human and animals studies. Some of the inconsistencies are due to non-comparable and biased methods that were applied on thin transversal sections, especially in muscles with complicated morphological structures, such as in human masseter muscle. We present a new immunohistochemical method for staining capillaries and muscle fibres in 100 µm thick sections as well as novel approach to 3D visualization of capillaries and muscle fibres. Applying confocal microscopy and virtual 3D stereological grids, or tracing capillaries in virtual reality, length of capillaries within a muscle volume or length of capillaries adjacent to muscle fibre per fibre length, fibre surface or fibre volume were evaluated in masseter muscle of young and old subjects by an unbiased approach. Our findings show that anatomic capillarity is well maintained in masseter muscle in old subjects; however, vascular remodelling occurs with age, which could be a response to changed muscle function and age-related muscle fibre type transformations.

  5. Inhibitory reflex responses of masseter muscle in anterior open bite

    OpenAIRE

    Priyada, SANTILAKANAWONG; Hiroaki, KIRIMOTO; Yoichiro, SEKI; Kunimichi, SOMA; Orthodontic Science, Department of Orofacial Development and Function, Division of Oral Health Sciences, Graduate School, Tokyo Medical and Dental University

    2003-01-01

    Animal studies indicated that loss of occlusal contact between maxillary and mandibular teeth causes altered functional activity of periodontal mechanoreceptors. The alteration of periodontal mechanoreceptors may influence jawmuscle reflex and masticatory muscle activity. In this study, the inhibitory reflex response of masseter muscle in subjects with anterior open bite was investigated. The study population included 10 subjects with anterior open bite with no muscle pain or craniomandibular...

  6. Ultrastructural features of masseter muscle exhibiting altered occlusal relationship—a study in a rodent model

    Science.gov (United States)

    Lisboa, Marcio V.; Aciole, Gilberth T. S.; Oliveira, Susana C. P. S.; Marques, Aparecida M. C.; Baptista, Abrahão F.; Pinheiro, Antonio L. B.; Aguiar, Marcio C.; Santos, Jean N.

    2010-05-01

    The role of occlusion on Tempormandibular Disorders (TMD) is still unclear, mainly regarding muscular function. The aim of this study was to evaluate the occlusion highlights on masseter ultra morphology. Twenty Wistar rats were randomly divided in four groups: 10 for control group, 10 for occlusal alteration group (CCO). Rats underwent unilateral amputation of the left inferior and superior molar cusps to simulate an occlusal wear situation. The rats of control group had no occlusal wear. Half of the animals of each group was sacrificed in 14 days after the occlusal consuming and half 30 days after the occlusal consuming. The masseter muscles ipsilateral to the amputated molars were excised and processed for light microscopy, electron microscopy. The light microscopy did not show differences between the groups. The electron microscopy was able to detect a degree of intracellular damage in muscle fibers of CCO group: swollen mitochondria with disrupted cristae and cleared matrix, signs of hypercontraction of I bands and myofibril disorganization.

  7. Relationship between masseter muscle size and maxillary morphology.

    Science.gov (United States)

    Uchida, Yasuki; Motoyoshi, Mitsuru; Shigeeda, Toru; Shinohara, Akihiko; Igarashi, Yu; Sakaguchi, Masahito; Shimizu, Noriyoshi

    2011-12-01

    The aim of this study was to investigate the relationship between masseter muscle size and craniofacial morphology, focusing on the maxilla. Twenty-four patients (11 males and 13 females; mean age 27.6 ± 5.6 years) underwent cephalometric analyses. Ultrasonography was used to measure the cross-sectional area (CSA) of the masseter muscle and bite force was measured using pressure sensitive film. The results showed that CSA-relaxed was positively correlated with upper anterior face height (UAFH)/total anterior face height (TAFH) and negatively with lower anterior face height (LAFH)/TAFH and LAFH (P < 0.05). CSA-clenched was correlated positively with SN-palatal, FH-palatal, UAFH/TAFH, and lower posterior face height (LPFH)/total posterior face height (TPFH) and negatively with LAFH/TAFH, LAFH, upper posterior face height (UPFH)/TPFH, and UPFH (P < 0.05). Bite force was positively correlated with LPFH/TPFH and negatively with UPFH/TPFH (P < 0.05). As the masseter became larger, the anterior maxillary region tended to shift downwards relative to the cranial base, whereas the posterior region tended to shift upwards. The decrease in LAFH/TAFH and increase in LPFH/TPFH as the size of the masseter muscle increases may be influenced not only by the inclination of the mandibular plane but also by the clockwise rotation of the maxilla.

  8. Acoustic myography, electromyography and bite force in the masseter muscle.

    Science.gov (United States)

    Tortopidis, D; Lyons, M F; Baxendale, R H

    1998-12-01

    Acoustic myography (AMG) offers some advantages over electromyography (EMG) in certain circumstances, but the use of AMG on the jaw-closing muscles has not been fully tested. The purpose of this study was to examine the relationship between AMG, EMG and force in the masseter muscles of nine healthy male subjects. The AMG was recorded using a piezoelectric crystal microphone and the EMG was recorded simultaneously with surface electrodes. Force was recorded between the anterior teeth with a strain-gauge transducer. Analysis showed that Pearson's correlation coefficient was 0.913 for force/AMG and 0.973 for force/EMG in all subjects, indicating a linear relationship between force, AMG and EMG at the four different force levels tested (25-75% of maximum). It is apparent that AMG may be used as an accurate monitor of masseter muscle force production, although some care is required in the technique.

  9. Hipertrofia benigna do músculo masseter Benign masseter muscle hypertrophy

    Directory of Open Access Journals (Sweden)

    Daniel Zeni Rispoli

    2008-10-01

    Full Text Available A hipertrofia idiopática do músculo masseter (HIM é uma patologia pouco freqüente e de causa desconhecida. Alguns autores correlacionam tal condição com hábitos de mascar gomas, disfunção da articulação temporomandibular (ATM, hipertrofias congênitas e funcionais, e distúrbios emocionais (nervosismo e ansiedade. A maioria dos pacientes queixa-se da alteração estética decorrente da assimetria facial, também chamada "face quadrada", no entanto, sintomas como trismo, protrusão e bruxismo também podem ocorrer. Os objetivos deste estudo foram: relatar um caso de HIM e descrever a sintomatologia e o tratamento realizado. O paciente relatava aumento bilateral na região do ângulo da mandíbula de evolução lenta e progressiva. Negava dor ou desconforto, porém se queixava de otalgia bilateral, trismo noturno e ansiedade. Ao exame físico, observou-se hipertrofia bilateral de masseter sem alterações inflamatórias no local. Foi indicado tratamento cirúrgico com abordagem extra-oral. Exames complementares são indicados na dúvida diagnóstica. A conduta terapêutica varia de conservadora a cirúrgica, sendo que esta depende principalmente da experiência e da habilidade do cirurgião.Idiopathic hypertrophy of the masseter muscle is a rare disorder of unknown cause. Some authors associate it with the habit of chewing gum, temporo-mandibular joint disorder, congenital and functional hypertrophies, and emotional disorders (stress and nervousness. Most patients complain of the cosmetic change caused by facial asymmetry, also called square face, however, symptoms such as trismus, protrusion and bruxism may also occur. The goals of the present investigation were: to report a case of idiopathic masseter hypertrophy, describe its symptoms and treatment. The patient reported bilateral bulging in the region of the mandible angle, of slow and progressive evolution. He did not complain of pain or discomfort, however there was bilateral

  10. Ultrasound measurements of the masseter muscle as predictors of cephalometric indices in orthodontics: a pilot study.

    Science.gov (United States)

    Naser-Ud-Din, S; Sampson, W J; Dreyer, C W; Thoirs, K

    2010-09-01

    This study investigated the potential of ultrasound measurements of the masseter muscle to accurately predict indices normally derived from cephalograms. Masseter muscle measurements on 11 adults (22 to 30 y) were made using lateral cephalometrics and extended field-of-view ultrasound. The ultrasound technique was validated in a simulation pilot study using 12 dry skulls and raw chicken breasts. Twenty cephalometric variables were analyzed against four ultrasound measurements of the masseter muscle. Highly significant correlations (r = 0.81-0.85, p = 0.001-0.002) between ultrasound measurements of the masseter muscle and cephalometric measurements representing the length of the superficial masseter muscle, the length and shape of the mandible and vertical facial proportions were demonstrated. Predictive equations from regression analyses were constructed to deduce ramus length and shape from the ultrasound measurements. The results provide pilot data suggesting that ultrasound is a potential clinical tool for sequential evaluation of masseter muscle length in orthodontics and facial muscle growth studies.

  11. Fatigue in the masseter and temporalis muscles at constant load.

    Science.gov (United States)

    Sforza, Chiarella; Zanotti, Gianfranco; Mantovani, Enrica; Ferrario, Virgilio F

    2007-01-01

    Fatigue is usually defined as the point at which a particular level of force can be no longer maintained. In the present study, surface EMG of the masseter and temporalis anterior muscles was measured in ten healthy young adults performing a unilateral molar (right side) clench. The subjects clenched on a bite force transducer at a fixed force level of 13 kg (127 N) as long as they could (endurance). The test ended when the subjects could no longer produce the required bite force. From the EMG recordings, the median power frequency was calculated at the beginning of the task (T0), after one minute of clenching (T1), and at the end of the task (T2, endurance time). For each subject and muscle, percentage decrements in the median power frequency were also computed at T1 and T2. Endurance time ranged between 79 and 470 s. Significant modifications in the median power frequency in both masseter muscles (right side, p=0.003; left side, p=0.02, analysis of variance) were found, with a significant difference for the median frequency at T2 (p0.05). Additionally, at T1, significant percentage decrements in the median power frequency were found for both right side muscles (p0.05) were not significant. A significant effect of side was found (p=0.007, analysis of variance), without effects of muscle and no muscle x side interaction. At T2, both masseter muscles and the right side temporalis had a significant modification in their median power frequency. Overall, the modifications were larger in the masseter than in the temporalis muscles (p=0.022, analysis of variance), without effects of side and no muscle x side interaction. In conclusion, a fixed submaximal muscular contraction provoked fatigue modifications in the EMG power spectra that were well comparable to those obtained in previous investigations using forces computed as percentages of individually assessed maximum bite forces The present protocol (endurance clenching at a fixed force level) could be used as both a

  12. Prolonging the duration of masseter muscle reduction by adjusting the masticatory movements after the treatment of masseter muscle hypertrophy with botulinum toxin type a injection.

    Science.gov (United States)

    Wei, Jiao; Xu, Hua; Dong, Jiasheng; Li, Qingfeng; Dai, Chuanchang

    2015-01-01

    Botulinum toxin type A (BTX-A) is widely used for the clinical treatment of masseteric hypertrophy. Until now, few reports have discussed how to prolong the duration of its effectiveness. This study evaluated that purposely adjusting the masticatory movements is possible of postponing the masseter muscle rehypertrophy. Ninety-eight patients were randomly and equally divided into 2 groups, and 35 U BTX-A per side was injected into the masseters. The thickness and volume of the masticatory muscles were measured by ultrasound and computerized tomography, respectively. Patients in Group 1 were instructed to strengthen their masticatory effort during the denervated atrophic stage of the masseter (the interval was evaluated by real-time ultrasound monitoring), whereas patients in Group 2 were not given this instruction. When the masseter muscle began to recover, patients in both groups were instructed to reduce their chewing. The duration of the masseter muscle rehypertrophy was significantly prolonged in Group 1 patients. The thickness and the volume of the other masticatory muscles were significantly increased in Group 1 but were either slightly decreased or insignificantly different in Group 2. Purposely strengthening masticatory muscle movement during the denervated atrophic stage of the masseter can prolong the duration of masseter rehypertrophy.

  13. Functional compartmentalization of the human superficial masseter muscle.

    Directory of Open Access Journals (Sweden)

    Rodrigo A Guzmán-Venegas

    Full Text Available Some muscles have demonstrated a differential recruitment of their motor units in relation to their location and the nature of the motor task performed; this involves functional compartmentalization. There is little evidence that demonstrates the presence of a compartmentalization of the superficial masseter muscle during biting. The aim of this study was to describe the topographic distribution of the activity of the superficial masseter (SM muscle's motor units using high-density surface electromyography (EMGs at different bite force levels. Twenty healthy natural dentate participants (men: 4; women: 16; age 20±2 years; mass: 60±12 kg, height: 163±7 cm were selected from 316 volunteers and included in this study. Using a gnathodynamometer, bites from 20 to 100% maximum voluntary bite force (MVBF were randomly requested. Using a two-dimensional grid (four columns, six electrodes located on the dominant SM, EMGs in the anterior, middle-anterior, middle-posterior and posterior portions were simultaneously recorded. In bite ranges from 20 to 60% MVBF, the EMG activity was higher in the anterior than in the posterior portion (p-value = 0.001.The center of mass of the EMG activity was displaced towards the posterior part when bite force increased (p-value = 0.001. The topographic distribution of EMGs was more homogeneous at high levels of MVBF (p-value = 0.001. The results of this study show that the superficial masseter is organized into three functional compartments: an anterior, a middle and a posterior compartment. However, this compartmentalization is only seen at low levels of bite force (20-60% MVBF.

  14. Functional compartmentalization of the human superficial masseter muscle.

    Science.gov (United States)

    Guzmán-Venegas, Rodrigo A; Biotti Picand, Jorge L; de la Rosa, Francisco J Berral

    2015-01-01

    Some muscles have demonstrated a differential recruitment of their motor units in relation to their location and the nature of the motor task performed; this involves functional compartmentalization. There is little evidence that demonstrates the presence of a compartmentalization of the superficial masseter muscle during biting. The aim of this study was to describe the topographic distribution of the activity of the superficial masseter (SM) muscle's motor units using high-density surface electromyography (EMGs) at different bite force levels. Twenty healthy natural dentate participants (men: 4; women: 16; age 20±2 years; mass: 60±12 kg, height: 163±7 cm) were selected from 316 volunteers and included in this study. Using a gnathodynamometer, bites from 20 to 100% maximum voluntary bite force (MVBF) were randomly requested. Using a two-dimensional grid (four columns, six electrodes) located on the dominant SM, EMGs in the anterior, middle-anterior, middle-posterior and posterior portions were simultaneously recorded. In bite ranges from 20 to 60% MVBF, the EMG activity was higher in the anterior than in the posterior portion (p-value = 0.001).The center of mass of the EMG activity was displaced towards the posterior part when bite force increased (p-value = 0.001). The topographic distribution of EMGs was more homogeneous at high levels of MVBF (p-value = 0.001). The results of this study show that the superficial masseter is organized into three functional compartments: an anterior, a middle and a posterior compartment. However, this compartmentalization is only seen at low levels of bite force (20-60% MVBF).

  15. 不同开口度对大鼠咬肌及颞下颌关节的影响%Effects of mouth opening degree on masseter muscle and temporomandibular joint of rats

    Institute of Scientific and Technical Information of China (English)

    党薇; 于世宾; 何惠明; 李甜

    2013-01-01

    目的:观察不同开口度对大鼠咬肌及颞下颌关节的影响,探索实验操作过程中大鼠最适张口度.方法:选择头部发育完全的12周龄雄性SD大鼠25只,随机分为1个对照组和4个实验组(每组5只),分别给予不同开口度处理.所有大鼠经麻醉后除对照组(开口度0 mm)外,4个实验组分别给予10、15、20、25 mm不同开口度的被动张口干预.每天干预1次,每次0.5h,连续7d.干预期间,每天观察并记录各大鼠的体质量变化情况.连续处理7d后处死大鼠,完整取出大鼠颞下颌关节及咬肌,常规组织学观察.结果:10、15、20 mm组与对照组相比,大鼠体质量、颞下颌关节及咬肌组织等结构均无明显差别;而25mm组大鼠体质量增长缓慢,从干预后第2天起各时间点的体质量均明显低于对照组和其他实验组,差异有统计学意义(P<0.05);而且咬肌肌纤维间有红细胞渗出和炎症细胞聚集;颞下颌关节髁突大量软骨细胞增殖,髁突软骨厚度明显增加.结论:大鼠开口度达到25 mm,并持续0.5h连续7d时,会引起其咬肌及颞下颌关节显微结构的变化.%AIM: To investigate the effects of mouth opening degree on masseter muscle and temporoman dibular joint in rats so as to find out the most suitable degree of mouth opening in experimental procedures. METHODS: 25 male SD rats aged 12 weeks were randomly divided into 5 groups(n =5). After anesthesia the rats were intervened with different degrees of passive mouth opening (10 mm, 15 mm, 20 mm and 25 mm) for 0. 5 h a day. The control rats received no intervention. Body weight of the rats was recorded during the intervention period. After 7 days of intervention, all rats were sacrificed, the masseter muscles and the temporomandibular joints were taken and examined by histology. RESULTS: No significant change was found among the 10 mm, 15 mm and 20 mm groups and the control group in terms of body weight and histological feature (P>0

  16. Masseter muscle rigidity: Atypical malignant hyperthermia presentation or isolated event?

    Directory of Open Access Journals (Sweden)

    Onyeka Tonia

    2010-01-01

    Full Text Available This report describes a case of masseter muscle rigidity encountered at the start of an elective gynaecological procedure. At preoperative assessment, the patient, a 41-year old woman with a previous non-eventful surgical and anesthetic history was given a Mallampati score of 3. Following suxamethonium administration, full mouth opening proved difficult. Laryngoscopy and tracheal intubation were not possible leading to the eventual use of a laryngeal mask airway and resulting in a successful anaesthetic outcome. A number of possibilities that may account for this situation as well as viable options for airway access in such cases are discussed below.

  17. Effects of chronic Akt/mTOR inhibition by rapamycin on mechanical overload-induced hypertrophy and myosin heavy chain transition in masseter muscle.

    Science.gov (United States)

    Umeki, Daisuke; Ohnuki, Yoshiki; Mototani, Yasumasa; Shiozawa, Kouichi; Fujita, Takayuki; Nakamura, Yoshiki; Saeki, Yasutake; Okumura, Satoshi

    2013-01-01

    To examine the effects of the Akt/mammalian target of rapamycin (mTOR) pathway on masseter muscle hypertrophy and myosin heavy chain (MHC) transition in response to mechanical overload, we analyzed the effects of bite-opening (BO) on the hypertrophy and MHC composition of masseter muscle of BO-rats treated or not treated with rapamycin (RAPA), a selective mTOR inhibitor. The masseter muscle weight in BO-rats was significantly greater than that in controls, and this increase was attenuated by RAPA treatment. Expression of slow-twitch MHC isoforms was significantly increased in BO-rats with/without RAPA treatment, compared with controls, but the magnitude of the increase was much smaller in RAPA-treated BO-rats. Phosphorylation of p44/42 MAPK (ERK1/2), which preserves fast-twitch MHC isoforms in skeletal muscle, was significantly decreased in BO-rats, but the decrease was abrogated by RAPA treatment. Calcineurin signaling is known to be important for masseter muscle hypertrophy and fast-to-slow MHC isoform transition, but expression of known calcineurin activity modulators was unaffected by RAPA treatment. Taken together, these results indicate that the Akt/mTOR pathway is involved in both development of masseter muscle hypertrophy and fast-to-slow MHC isoform transition in response to mechanical overload with inhibition of the ERK1/2 pathway and operates independently of the calcineurin pathway.

  18. MYOSITIS OSSIFICANS TRAUMATICA OF THE MASSETER MUSCLE- review of the literature and case report.

    Directory of Open Access Journals (Sweden)

    Elitsa G. Deliverska

    2013-11-01

    Full Text Available Introduction: Myositis ossificans traumatica (MOT is known mostly in the orthopedic literature as non-neoplastic, heterotopic bone formation within muscle or fascia, presumably due to acute trauma or repeated injury. Myositis ossificans traumatica of the masseter muscle is uncommon disease producing limitation of opening of the jaws. Purpose: To present a case of MOT of the masseter muscle in patient with history of facial trauma. Material and methods: The medical history of a 53 years patient with complaint of decreasing ability to open his mouth over the past 10 years after a blow to face. CT revealed enlarged calcification in the left masseter muscle.Conclusion: Treatment of MOT of the masseter muscle is surgical- total extirpation of the ossified muscle but also surgical techniques including osteotomy that involve the muscle attachment region should be considered and after that appropriate physical therapy.

  19. Muscle spindle composition and distribution in human young masseter and biceps brachii muscles reveal early growth and maturation.

    Science.gov (United States)

    Osterlund, Catharina; Liu, Jing-Xia; Thornell, Lars-Eric; Eriksson, Per-Olof

    2011-04-01

    Significant changes in extrafusal fiber type composition take place in the human masseter muscle from young age, 3-7 years, to adulthood, in parallel with jaw-face skeleton growth, changes of dentitions and improvement of jaw functions. As motor and sensory control systems of muscles are interlinked, also the intrafusal fiber population, that is, muscle spindles, should undergo age-related changes in fiber type appearance. To test this hypothesis, we examined muscle spindles in the young masseter muscle and compared the result with previous data on adult masseter spindles. Also muscle spindles in the young biceps brachii muscle were examined. The result showed that muscle spindle composition and distribution were alike in young and adult masseter. As for the adult masseter, young masseter contained exceptionally large muscle spindles, and with the highest spindle density and most complex spindles found in the deep masseter portion. Hence, contrary to our hypothesis, masseter spindles do not undergo major morphological changes between young age and adulthood. Also in the biceps, young spindles were alike adult spindles. Taken together, the results showed that human masseter and biceps muscle spindles are morphologically mature already at young age. We conclude that muscle spindles in the human young masseter and biceps precede the extrafusal fiber population in growth and maturation. This in turn suggests early reflex control and proprioceptive demands in learning and maturation of jaw motor skills. Similarly, well-developed muscle spindles in young biceps reflect early need of reflex control in learning and performing arm motor behavior. Copyright © 2011 Wiley-Liss, Inc.

  20. Replicability of electromyographic recordings of the masseter muscle during mastication.

    Science.gov (United States)

    Garrett, N R; Kapur, K K

    1986-03-01

    This study evaluates the reliability of a method to duplicate the location of surface electrodes for recording the electromyographic activity of masseter muscles during mastication and quantifying the activity by a microcomputer system. A plastic framework consisting of a bite fork and electrode positioners was used to place the electrodes by relating the positioners to an occlusal index and keeping this relationship constant at subsequent sittings. EMG recordings were repeated on two different days for each of 10 subjects while they performed standardized masticatory performance tests with peanuts and carrots. The muscle activity recorded with hardware integrators was an average of 26.7% of the computerized software integrations but measures derived from the two methods of integration were highly correlated (r = 0.965) and yielded similar results. Significant correlations were found between test sessions for each measure of masticatory performance and integrated EMG activity for ipsilateral and contralateral muscles. For each subject, no significant differences were found between sessions for any masticatory performance or EMG variable. The results indicate that reliable inter session EMG recordings during mastication can be made by using the template for positioning of the electrodes. In addition, the microcomputer data acquisition system provides results comparable to those obtained with conventional hardware integrators, with the added benefit of providing information on each individual stroke and its various components.

  1. Muscle fatigue in the temporal and masseter muscles in patients with temporomandibular dysfunction.

    Science.gov (United States)

    Woźniak, Krzysztof; Lipski, Mariusz; Lichota, Damian; Szyszka-Sommerfeld, Liliana

    2015-01-01

    The aim of this study is to evaluate muscle fatigue in the temporal and masseter muscles in patients with temporomandibular dysfunction (TMD). Two hundred volunteers aged 19.3 to 27.8 years (mean 21.50, SD 0.97) participated in this study. Electromyographical (EMG) recordings were performed using a DAB-Bluetooth Instrument (Zebris Medical GmbH, Germany). Muscle fatigue was evaluated on the basis of a maximum effort test. The test was performed during a 10-second maximum isometric contraction (MVC) of the jaws. An analysis of changes in the mean power frequency of the two pairs of temporal and masseter muscles (MPF%) revealed significant differences in the groups of patients with varying degrees of temporomandibular disorders according to Di (P muscle fatigue of the temporal and masseter muscles correlated with the intensity of temporomandibular dysfunction symptoms in patients. The use of surface electromyography in assessing muscle fatigue is an excellent diagnostic tool for identifying patients with temporomandibular dysfunction.

  2. Muscle Fatigue in the Temporal and Masseter Muscles in Patients with Temporomandibular Dysfunction

    Directory of Open Access Journals (Sweden)

    Krzysztof Woźniak

    2015-01-01

    Full Text Available The aim of this study is to evaluate muscle fatigue in the temporal and masseter muscles in patients with temporomandibular dysfunction (TMD. Two hundred volunteers aged 19.3 to 27.8 years (mean 21.50, SD 0.97 participated in this study. Electromyographical (EMG recordings were performed using a DAB-Bluetooth Instrument (Zebris Medical GmbH, Germany. Muscle fatigue was evaluated on the basis of a maximum effort test. The test was performed during a 10-second maximum isometric contraction (MVC of the jaws. An analysis of changes in the mean power frequency of the two pairs of temporal and masseter muscles (MPF% revealed significant differences in the groups of patients with varying degrees of temporomandibular disorders according to Di (P<0.0000. The study showed an increase in the muscle fatigue of the temporal and masseter muscles correlated with the intensity of temporomandibular dysfunction symptoms in patients. The use of surface electromyography in assessing muscle fatigue is an excellent diagnostic tool for identifying patients with temporomandibular dysfunction.

  3. Muscle Fatigue in the Temporal and Masseter Muscles in Patients with Temporomandibular Dysfunction

    Science.gov (United States)

    Woźniak, Krzysztof; Lipski, Mariusz; Lichota, Damian

    2015-01-01

    The aim of this study is to evaluate muscle fatigue in the temporal and masseter muscles in patients with temporomandibular dysfunction (TMD). Two hundred volunteers aged 19.3 to 27.8 years (mean 21.50, SD 0.97) participated in this study. Electromyographical (EMG) recordings were performed using a DAB-Bluetooth Instrument (Zebris Medical GmbH, Germany). Muscle fatigue was evaluated on the basis of a maximum effort test. The test was performed during a 10-second maximum isometric contraction (MVC) of the jaws. An analysis of changes in the mean power frequency of the two pairs of temporal and masseter muscles (MPF%) revealed significant differences in the groups of patients with varying degrees of temporomandibular disorders according to Di (P < 0.0000). The study showed an increase in the muscle fatigue of the temporal and masseter muscles correlated with the intensity of temporomandibular dysfunction symptoms in patients. The use of surface electromyography in assessing muscle fatigue is an excellent diagnostic tool for identifying patients with temporomandibular dysfunction. PMID:25883949

  4. [Electromyographic (EMG) electrode impedance and EMG activity from anterior temporal muscle and masseter muscle].

    Science.gov (United States)

    Takarada, T; Alvarado Larrinaga, G; Nishida, F; Nishino, M

    1989-01-01

    The value and change with time of the impedance of surface EMG electrodes and the effects of their difference between the bipolar electrodes on the electromyographic activity from the anterior temporal muscle and the masseter muscle in six adult male subjects with normal occlusion were studied. The results were as follows: 1. In the anterior temporal muscle, if the impedance of the electrode was under 20 k omega it was stable from just after the electrode disc was applied to the skin. In the masseter muscle, if the impedance was under 30 k omega it became stable within two minutes after the electrode was applied. 2. The difference of impedance between the bipolar EMG electrodes did not correlate with EMG activity.

  5. Electromyographic analysis of masseter muscle in newborns during suction in breast, bottle or cup feeding

    National Research Council Canada - National Science Library

    França, Ellia C L; Sousa, Cejana B; Aragão, Lucas C; Costa, Luciane R

    2014-01-01

    .... The aim of this study was to analyze the electrical activity of the masseter muscle using surface electromyography during suction in term newborns by comparing breastfeeding, bottle and cup feeding...

  6. Simultaneous Bilateral Hypertrophies of the Parotid Gland and Masseter Muscle: Case Report.

    Science.gov (United States)

    Prabhu, Rohan; Mandel, Louis

    2017-01-01

    Increased salivary demand can lead to enlarged parotid salivary glands, and increased activity of the masseter muscles can cause masseter hypertrophy. This report describes a most unusual case of simultaneous bilateral hypertrophies of the parotid gland and masseter muscle originating from the very extensive habit of chewing gum. An extensive literature review uncovered many cases of the independent existence of masseteric or parotid hypertrophy, but no example of the simultaneous occurrence of these 2 conditions. Copyright © 2016 American Association of Oral and Maxillofacial Surgeons. Published by Elsevier Inc. All rights reserved.

  7. [Muscle action potential and masticatory rhythm of anterior temporal and masseter muscles in children and adults].

    Science.gov (United States)

    Alvarado Larrinaga, G; Takarada, T; Nishida, F; Nishino, M

    1989-01-01

    For the investigation of the functional change of the masticatory muscles along with growth and development, electromyographic evaluation was carried out. The subjects were 6 children (5 males and 1 female) with full deciduous dentition (Hellman's dental age IIA) aged 4.5 +/- 0.2 years and 6 adults (4 males and 2 females) with full permanent dentition aged 27.7 +/- 3.8 years. EMG signals were recorded bilaterally by means of bipolar silver surface electrodes from the anterior temporal and masseter muscles when the subjects were chewing chewing gum or performing maximum clenches in intercuspal position. The cumulative power values from 62.5 to 1000 Hz in the EMG power spectrum during chewing or clenching were calculated as the muscle action potential. The ratio of the action potential of each muscle to the total action potential of four muscles were analyzed. Masticatory rhythm during chewing was analyzed by means of the time parameter (duration, interval and cycle) and their coefficients of variation. The results were as follows: 1. In children the temporal muscles predominated in chewing and clenching, whereas in adults there were three types with Temporal muscles predominating, Masseter muscles predominating and both muscles sharing equally. 2. No statistically significant differences between children and adults were observed in the duration, interval and cycle. 3. In adults the coefficients of variation of the duration, interval and cycle were smaller and the masticatory rhythm was more stable than in children.

  8. Macrophages and mast cells in dystrophic masseter muscle: a light and electron microscopic study

    DEFF Research Database (Denmark)

    Kirkeby, S; Mikkelsen, H

    1988-01-01

    Macrophages and mast cells in masseter muscle from normal and dystrophic mice were studied by light and electron microscopy. Acid phosphatase activity and FITC-dextran were used to identify and describe macrophages. Toluidine blue was used as a marker for mast cells. In dystrophic muscle, the num......Macrophages and mast cells in masseter muscle from normal and dystrophic mice were studied by light and electron microscopy. Acid phosphatase activity and FITC-dextran were used to identify and describe macrophages. Toluidine blue was used as a marker for mast cells. In dystrophic muscle...

  9. A Case of Painful Hemimasticatory Spasm with Masseter Muscle Hypertrophy Responsive to Botulinum Toxin

    Directory of Open Access Journals (Sweden)

    Jin-Hyuck Kim

    2009-10-01

    Full Text Available Hemimasticatory spasm (HMS is a rare disorder of the trigeminal nerve characterized by paroxysmal involuntary contractions of the unilateral jaw-closing muscles. HMS has been frequently described in association with facial hemiatrophy or localized scleroderma. A 42-year-old female presented with involuntary paroxysmal spasms of the left face, of 6 months duration. Her lower face on the left was markedly hypertrophied without skin lesions. An electrophysiological study indicated that the masseter reflexes and masseteric silent period were attenuated on the affected side. Surface electromyography demonstrated irregular bursts of motor unit potentials at high frequencies up to 200 Hz. Magnetic resonance imaging of the head showed marked hypertrophy of the left masseter muscle. Biopsy of the hypertrophied masseter muscle was normal. Repeated local injections of botulinum toxin noticeably reduced the size of the hypertrophied muscle as well as improved the patient’s symptoms.

  10. Feasibility of eliciting the H reflex in the masseter muscle in patients under general anesthesia.

    Science.gov (United States)

    Ulkatan, Sedat; Jaramillo, Ana Maria; Téllez, Maria J; Goodman, Robert R; Deletis, Vedran

    2017-01-01

    To explore the feasibility of eliciting the brainstem H reflex in the masseter muscle in patients under general anesthesia. We electrically stimulated the masseteric nerve, a branch of the trigeminal nerve, and recorded ipsilateral masseteric and temporalis muscle responses. We tested eight patients who presented with trigeminal neuralgia; one patient had a temporal bone tumor and one patient had a brainstem arteriovenous malformation. All responses were elicited when patients were under general anesthesia and before the initiation of surgery. The H reflex in the masseter muscle was reliably elicited in 70% of the patients. The reflexes met the usual criteria for the H reflex because they were elicited below the threshold of the direct M response, and their amplitudes decreased when the M response increased with stronger stimuli. The mean onset latencies of the masseter H reflex and the M response were 5.4±1.3ms and 2.6±0.6ms, respectively. In the present study, we provide evidence of the feasibility of eliciting the H reflex in the masseter muscles of patients under general anesthesia. The H reflex of the masseter muscle may represent a new method available for intraoperative monitoring. Specifically, this method may be important for the monitoring of brainstem functional integrity, particularly in the midbrain and mid-pons, in addition to the trigeminal nerve path. Copyright © 2016 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.

  11. Masseter Muscle Activity in Track and Field Athletes: A Pilot Study

    Science.gov (United States)

    Nukaga, Hideyuki; Takeda, Tomotaka; Nakajima, Kazunori; Narimatsu, Keishiro; Ozawa, Takamitsu; Ishigami, Keiichi; Funato, Kazuo

    2016-01-01

    Teeth clenching has been shown to improve remote muscle activity (by augmentation of the Hoffmann reflex), and joint fixation (by decreased reciprocal inhibition) in the entire body. Clenching could help maintain balance, improve systemic function, and enhance safety. Teeth clenching from a sports dentistry viewpoint was thought to be important and challenging. Therefore, it is quite important to investigate mastication muscles’ activity and function during sports events for clarifying a physiological role of the mastication muscle itself and involvement of mastication muscle function in whole body movement. Running is a basic motion of a lot of sports; however, a mastication muscles activity during this motion was not clarified. Throwing and jumping operation were in a same situation. The purpose of this study was to investigate the presence or absence of masseter muscle activity during track and field events. In total, 28 track and field athletes took part in the study. The Multichannel Telemetry system was used to monitor muscle activity, and the electromyograms obtained were synchronized with digital video imaging. The masseter muscle activity threshold was set 15% of maximum voluntary clenching. As results, with few exceptions, masseter muscle activity were observed during all analyzed phases of the 5 activities, and that phases in which most participants showed masseter muscle activity were characterized by initial acceleration, such as in the short sprint, from the commencement of throwing to release in both the javelin throw and shot put, and at the take-off and landing phases in both jumps. PMID:27708727

  12. Effects of experimental nasal obstruction on human masseter and suprahyoid muscle activities during sleep.

    Science.gov (United States)

    Hiyama, Shigetoshi; Ono, Takashi; Ishiwata, Yasuo; Kuroda, Takayuki; Ohyama, Kimie

    2003-04-01

    The effect of nasal obstruction on nocturnal masseter and suprahyoid muscle activities using a newly developed portable electromygram (EMG)-recording unit was examined. Ten healthy Japanese males participated in this study. EMG activities of both the right masseter and bilateral suprahyoid muscles were recorded with a portable EMG-recording unit. At midnight, the subject was asked to lie on a bed after complete preparation with surface electrodes. After maximal clenching and jaw-opening effort (100% maximum voluntary contribution), the subject was allowed to fall asleep. In the first half of the night, EMG activities were recorded for about three hours of sleep without nasal obstruction. In the second half of the night, EMG activities were recorded for about three hours of sleep with nasal obstruction. In both muscles, there were no significant changes in either the maximal EMG activities or the number of events beyond 40% MVC with nasal obstruction. But in an evaluation based on the distribution of muscle activities, the EMG activity of the masseter muscle tended to decrease (P = .07) and that of the suprahyoid muscles increased significantly (P = .02) with nasal obstruction. These results suggest that nasal obstruction could modulate the activities of the masseter and suprahyoid muscles during sleep.

  13. Antero-posterior activity changes in the superficial masseter muscle after exposure to experimental pain.

    Science.gov (United States)

    Türp, Jens C; Schindler, Hans J; Pritsch, Maria; Rong, Qiguo

    2002-04-01

    The aim of this randomized, controlled, double-blind study was to examine how the activation pattern of the masseter muscle changes during natural function when experimental pain is induced in a discrete anterior area of the muscle. In 20 subjects, three bipolar surface electrodes and three intramuscular fine-wire electrodes (antero-posterior mapping) were simultaneously attached above and in the right masseter muscle to record the electromyographic (EMG) activity during unilateral chewing before and after infusion of a 0.9% isotonic and 5% hypertonic saline bolus in the anterior area of the muscle. The activity of the contralateral masseter muscle was registered by surface electrodes. In addition, the development of pain intensity was quantitatively measured with a numerical rating scale (NRS). While both saline concentrations caused pain, the hypertonic solution evoked stronger pain. The experiments also provided evidence of a significant although differential activity reduction of the ipsilateral masseter muscle in the antero-posterior direction. The activity reduction decreased with increasing distance from the location of the infusion. The results support the idea that the strategy of differential activation protects the injured muscle while simultaneously maintaining optimal function.

  14. Botulinum neurotoxin type A in the masseter muscle: Effects on incisor eruption in rabbits

    Science.gov (United States)

    Navarrete, Alfonso L.; Rafferty, Katherine L.; Liu, Zi Jun; Ye, Wenmin; Greenlee, Geoffrey M.; Herring, Susan W.

    2015-01-01

    Introduction Botulinum neurotoxins are responsible for the paralytic food poisoning, botulism. Commercial formulations such as botulinum neurotoxin type A are increasingly used for various conditions, including cosmetic recontouring of the lower face by injection of the large masseter muscles. The paralysis of a major muscle of mastication lowers occlusal force and thus might affect tooth eruption. The purpose of this study was to investigate the effects of unilateral masseter muscle injection of botulinum neurotoxin type A on the rate of eruption of incisors in a rabbit model. We hypothesized that the teeth would overerupt in an underloaded environment. Methods Forty rabbits were injected with either botulinum neurotoxin type A or saline solution in 1 masseter muscle. Mastication and muscle force production were monitored, and incisor eruption rate was assessed by caliper measurement of grooved teeth. Results The injection of saline solution had no effect. The masseter muscle injected with botulinum neurotoxin type A showed a dramatic loss of force 3 weeks after injection despite apparently normal mastication. Incisor eruption rate was significantly decreased for the botulinum neurotoxin type A group, an effect attributed to decreased attrition. Conclusions This study has implications for orthodontics. Although findings from ever-growing rabbit incisors cannot be extrapolated to human teeth, it is clear that botulinum neurotoxin type A caused a decrease in bite force that could influence dental eruption. PMID:23561411

  15. An Eectromyographic Ccomparison Between the Activities of Temporal and Masseter Muscles in Class III Skeletal

    Directory of Open Access Journals (Sweden)

    T Hossein-Zadeh-Nik

    2002-02-01

    Full Text Available Electromyographic (EMG investigations about the activities of the muscles have been the focus of attention for many years. In the field of orthodontics, investigators, among other things, tried to evaluate correlation between EMG activity, occlusal relationships and craniofacial morphology to analyze the effect of muscular activity, as an etiological factor in malocclusion. The purpose of the present investigation is to analyze the effect of EMG activity of temporal and masseter muscles quantitatively in skeletal class III malocclusion. 26 patients (9 to If years old, with class III malocclusion were selected and their EMG activity of temporal and masseter muscles in rest position, centric occlusion, clenching, mastication and swallowing were compared with 20 normal children at the same age range. Then the statistical correlation between 13 cephalometric parameters and EMG activities were analyzed and then the regression analysis was performed and the results were as follows:1- The mean amplitude of masseter and temporal muscles activity in rest position, centric occlusion, mastication, and clenching in class III samples were greater than normal group (PO.05.2- The mean duration of masseter and temporal muscles activity in rest position and centric occlusion in class III samples were more than normal group (PO.05.3- According to regression analysis, a linear correlation was observed between ANB angle and temporal muscle activity in rest and centric occlusion that was not observed in other cases.The findings of this study showed that difference in temporal muscle activity in class III malocclusion, in comparison with the normal group, is correlated with skeletal morphology of the face, but according to other investigations it is not ture for the masseter muscle.

  16. Comparative data from young men and women on masseter muscle fibres, function and facial morphology

    DEFF Research Database (Denmark)

    Tuxen, A.; Bakke, M.; Pinholt, E. M.

    1999-01-01

    The primary aim was to relate information about masseter muscle fibres and function to aspects of facial morphology in a group of healthy young men. The secondary aim was to investigate possible sex differences using data previously obtained from a comparable group of age-matched, healthy women....... Dental status and facial morphology were recorded in 13 male students aged 20-26 years. Functional examinations included bite-force measurements and electromyographic recordings of masseter activity. A biopsy was removed from the masseter of each participant during surgical extraction of a wisdom tooth......, and the tissue examined for myosin ATPase activity. Further, the cross-sectional areas of the different fibre types were measured. In spite of using age-matched healthy men and women with a full complement of teeth, statistically significant sex differences were found among measures related to muscle function...

  17. Body position effects on EMG activity of sternocleidomastoid and masseter muscles in healthy subjects.

    Science.gov (United States)

    Miralles, R; Palazzi, C; Ormeño, G; Giannini, R; Verdugo, F; Valenzuela, S; Santander, H

    1998-04-01

    This study was conducted in order to determine the effects of body position on integrated electromyographic (IEMG) activity of sternocleidomastoid and masseter muscles in 20 healthy subjects. EMG recordings at rest and during swallowing of saliva and maximal voluntary clenching were performed by placing surface electrodes on the sternocleidomastoid and masseter muscles (contralateral to the habitual side of sleeping of each subject), in the following body positions: standing, seated, supine, and lateral decubitus position. Significant higher EMG activities were recorded in the sternocleidomastoid muscle in the lateral decubitus position, whereas significant lower EMG activities were recorded in the masseter muscle in the supine position. This finding supports the idea that there may exist a differential modulation of the motor neuron pools of the sternocleidomastoid and masseter muscles of peripheral and/or central origin. Significant differences in the EMG pattern as well as in the levels of EMG activities upon variations in body positions were observed between healthy subjects and patients with myogenic craniomandibular dysfunction reported by Palazzi, et al.

  18. Efficacy of massage treatment technique in masseter muscle hardness: robotic experimental approach.

    Science.gov (United States)

    Hiraiwa, Yuichiro; Ariji, Yoshiko; Kise, Yoshitaka; Sakuma, Shigemitsu; Kurita, Kenichi; Ariji, Eiichiro

    2013-10-01

    The study aimed to clarify the masseter muscle hardness in patients with myofascial pain, to examine their changes after massage, and to analyze whether the hardness can be an index for massage treatment. Sixteen patients with myofascial pain (12 with unilateral and 4 with bilateral masseter muscle pain) and 24 healthy volunteers were enrolled in this study. The masseter hardness between patients and the healthy volunteers was compared. The changes in the hardness in patients after massage were examined. The relation of the hardness with massage regimens and efficacies was analyzed. There was a significant right-and-left difference of the hardness in patients, although there was no difference in the healthy volunteers. The hardness decreased after massage. The pretreatment asymmetry index of the hardness showed a significant correlation with the massage pressure. It was concluded that there was a significant difference between the right and left masseter hardness in patients with myofascial pain. After massage treatment, the masseter hardness and right-and-left difference decreased. The hardness may be an index for determining the massage pressure.

  19. Differential activity patterns in the masseter muscle under simulated clenching and grinding forces.

    Science.gov (United States)

    Schindler, H J; Türp, J C; Blaser, R; Lenz, J

    2005-08-01

    The aim of this study was to investigate (i) whether the masseter muscle shows differential activation under experimental conditions which simulate force generation during clenching and grinding activities; and (ii) whether there are (a) preferentially active muscle regions or (b) force directions which show enhanced muscle activation. To answer these questions, the electromyographic (EMG) activity of the right masseter muscle was recorded with five intramuscular electrodes placed in two deep muscle areas and in three surface regions. Intraoral force transfer and force measurement were achieved by a central bearing pin device equipped with three strain gauges (SG). The activity distribution in the muscle was recorded in four different mandibular positions (central, left, right, anterior). In each position, maximum voluntary contraction (MVC) was exerted in vertical, posterior, anterior, medial and lateral directions. The investigated muscle regions showed different amount of EMG activity. The relative intensity of the activation, with respect to other regions, changed depending on the task. In other words, the muscle regions demonstrated heterogeneous changes of the EMG pattern for the various motor tasks. The resultant force vectors demonstrated similar amounts in all horizontal bite directions. Protrusive force directions revealed the highest relative activation of the masseter muscle. The posterior deep muscle region seemed to be the most active compartment during the different motor tasks. The results indicate a heterogeneous activation of the masseter muscle under test conditions simulating force generation during clenching and grinding. Protrusively directed bite forces were accompanied by the highest activation in the muscle, with the posterior deep region as the most active area.

  20. The contribution of the deep fibers of the masseter muscle to selected tooth-clenching and chewing tasks.

    Science.gov (United States)

    Belser, U C; Hannam, A G

    1986-11-01

    Anatomically, the human masseter muscle consists of at least two portions (pars superficialis, pars profunda) with distinctly different fiber directions. The purpose of this study was to describe functional behavior in the deep fibers of the masseter muscle and to define any differences in its behavior from that of the superficial fibers. In 20 subjects, EMG activity of the superficial and the deep portions of the masseter muscle was recorded during specific parafunctional (intercuspal and eccentric tooth clenching) and functional (unilateral chewing) tests. Superficial and deep activity was measured with bipolar surface electrodes and intramuscular fine-wire electrodes. Simultaneously, displacement of a lower incisor point was recorded in three dimensions. The data were collected and stored for analysis by a disk-based computer system. The results indicated that changes in the direction of effort, in mandibular position, and in the side used for chewing all influenced activity in both parts of the muscle to different extents. The most distinct separation of activity occurred when intercuspal clenching was directed retrusively; the deep fibers of the masseter muscle response reduced to 47.5% of its maximum value while that of the superficial fibers of the masseter muscle fell to 5.5%. During chewing, activity in the deep fibers of masseter muscle was distributed evenly bilaterally, whereas that in the superficial fibers of the masseter muscle was biased significantly toward the chewing side. Differentiation of activity within the masseter muscle may be relevant to the distribution of regional tenderness in the muscle when it is involved in parafunctional activity.(ABSTRACT TRUNCATED AT 250 WORDS)

  1. Electromyographic and ultrasonographic evaluation of the masseter muscle individuals with unilateral peripheral facial paralysis

    Directory of Open Access Journals (Sweden)

    Sassi, Fernanda Chiarion

    2011-10-01

    Full Text Available Introduction: Individuals with peripheral Facial Paralysis (FP show conditions that lead to unilateral mastication, performed by the non-affected side, mainly due to the difficulty of action of the buccinator muscle. Objectives: characterize the motor control and morphology of the masseter muscle in individuals with unilateral peripheral FP through electromyographic and ultrasonographic evaluation. Method: 16 participants, of both sexes, with ages superior to 18 years old. The study group (SG consisted of 8 individuals who'd had idiopathic unilateral peripheral FP for more than 6 months; the control group (CG consisted of 8 normal individuals. All the subjects were submitted to the masseter muscle evaluation through surface electromyography (sEMG and ultrasonography (USG during the following tasks: rest, clenching with cotton roller between the teeth (CT and clenching with maximum intercuspation (MIC. Results: There was no statistically significant difference in comparisons within and between the groups concerning the hemifacial asymmetry, both for the sEMG and for the USG. Also there were no significant differences in the activation of the masticatory muscles (masseter and temporal in the sEMG. Conclusions: Both the motor control and the morphology of the masseter muscles in individuals with unilateral peripheral FP were similar to those of normal individuals. Although literature suggests that the demand of functional adaptations made by FP individuals could exceed the structural and functional tolerance of the temporomandibular joints, the results indicate that the length of analyzed patient's FP was not enough to generate anatomical and physiological differences in the masticatory muscles.

  2. Evaluation of sexual dimorphism and the relationship between craniofacial, dental arch and masseter muscle characteristics in mixed dentition

    OpenAIRE

    Marquezin, Maria Carolina Salomé; Andrade, Annicele da Silva; Rossi, Moara de; Gameiro, Gustavo Hauber; Gavião, Maria Beatriz Duarte; Castelo,Paula Midori

    2014-01-01

    Purpose: to evaluate sexual dimorphism and the relationship between craniofacial characteristics, dental arch morphology and masseter muscle thickness in children in the mixed dentition stage. Methods: the study sample comprised 32 children, aged 6-10 years (14♀/18♂) with normal occlusion. Craniofacial characteristics, dental morphology and masseter muscle thickness were evaluated by means of posteroanterior cephalometric radiographs, dental cast evaluation and ultrasound exam, respectively. ...

  3. Jaw-opening accuracy is not affected by masseter muscle vibration in healthy men.

    Science.gov (United States)

    Wiesinger, B; Häggman-Henrikson, B; Wänman, A; Lindkvist, M; Hellström, F

    2014-11-01

    There is a functional integration between the jaw and neck regions with head extension-flexion movements during jaw-opening/closing tasks. We recently reported that trigeminal nociceptive input by injection of hypertonic saline into the masseter muscle altered this integrated jaw-neck function during jaw-opening/closing tasks. Thus, in jaw-opening to a predefined position, the head-neck component increased during pain. Previous studies have indicated that muscle spindle stimulation by vibration of the masseter muscle may influence jaw movement amplitudes, but the possible effect on the integrated jaw-neck function is unknown. The aim of this study was to investigate the effect of masseter muscle vibration on jaw-head movements during a continuous jaw-opening/closing task to a target position. Sixteen healthy men performed two trials without vibration (Control) and two trials with bilateral masseter muscle vibration (Vibration). Movements of the mandible and the head were registered with a wireless three-dimensional optoelectronic recording system. Differences in jaw-opening and head movement amplitudes between Control and Vibration, as well as achievement of the predefined jaw-opening target position, were analysed with Wilcoxon's matched pairs test. No significant group effects from vibration were found for jaw or head movement amplitudes, or in the achievement of the target jaw-opening position. A covariation between the jaw and head movement amplitudes was observed. The results imply a high stability for the jaw motor system in a target jaw-opening task and that this task was achieved with the head-neck and jaw working as an integrated system.

  4. Effect of thyroid hypofunction on the masseter motor innervation pattern in developing rats

    Directory of Open Access Journals (Sweden)

    Farzaneh Ganji

    2006-01-01

    Full Text Available Introduction: The thyroid hormones have profound effects on the development of neuromuscular system. These hormones exert their influence on both muscle fibers and related motoneurons during development. The masseter is one of the most important muscles for mastication in mammals. We attempted to evaluate the effect of thyroid hormone deficiency on the morphological characteristics of masseteric motoneurons in the period of alteration from sucking to biting and chewing in the rat. Materials and Methods: To induce hypothyroidism, timed pregnant dams received 50 ppm antithyroid drug propylthiouracil (PTU in their drinking water and PTU was administered to the pups during suckling period. Horseradish peroxidase (HRP was injected into the masseter (0.5-5 μlit, 40% of normal and prenatal hypothyroid pups on postnatal days of 1, 7, 15, and 23 (n=24. After 24-48 hours, the 50 μm thick brainstem sections containing trigeminal motor nucleus were processed for TMB histochemical procedure and morphological characteristics of HRP labeled motoneurons and their HRP labeling intensity was evaluated. Student's t-test and two-way analysis of variance (ANOVA were used for statistical analysis. Results: No significant morphological differences were observed at the end of first week of life. On day 15, hypothyroid labeled masseteric motoneurons consisted of 70% small and 30% medium neurons versus 40% and 60% in normal pups respectively (p<0.05. At the time of weaning, the number of large motoneurons dropped to 30% of normal value (p<0.001 with few, short, and disoriented dendrites. Conclusion: The alteration in particular patterns of masseteric motoneuron morphology and a severe delay in size transition could affect the development and plasticity of oral motor behavior under congenital hypothyroidism.

  5. A Modelling of Normal and Abnormal EMG Silent Period Generation of Masseter Muscle

    Energy Technology Data Exchange (ETDEWEB)

    Kim, T.H.; Jeon, C.I. [University Of Seoul, Seoul (Korea); Lee, S.H. [Induk Institute of Technology, Seoul (Korea)

    2003-02-01

    This paper proposes a model of SP(silent period) generation in masseter muscle by means of computer simulation. The model is based on the anatomical and physiological properties of trigeminal nervous system. In determining the SP generation pathway, evoked SPs of masseter muscle after mechanical stimulation to the chin are divided into normal and abnormal group. Normal SP is produced by the activation of mechanoreceptors in periodontal ligament. The activation of nociceptors contributes to the latter part of normal SP, abnormal extended SP is produced. As a result, the EMG signal generated by a proposed SP generation model is similar to both real EMG signal including normal SP and abnormal extended SP with TMJ patients. The result of this study have shown differences of SP generation mechanism between subjects both with and without TMJ dysfunction. (author). 21 refs., 12 figs., 1 tab.

  6. Entropy as a new measure of mechanical pain sensitivity in the masseter muscle

    DEFF Research Database (Denmark)

    Castrillon, Eduardo; Sato, Hitoshi; Tanosoto, Tomohiro

    barely painful” and “100” defined as “most pain imaginable”. All subjects participated in 3 sessions in a randomized order with injections of glutamate (0.5 ml, 1 mol/L), lidocaine (0.5 ml, 1%) or isotonic saline (0.5 ml, 0.9%)into the mid-portion (X = 2, Y = 3) of the masseter muscle. All sessions...... and 2 kg stimulation (Plidocaine and placebo......ENTROPY AS A NEW MEASURE OF MECHANICAL PAIN SENSITIVITY IN THE MASSETER MUSCLE Author Block: E. E. Castrillon1, H. Sato2,3, T. Tanosoto4, T. Arima4, L. Baad-Hansen1, P. Svensson1, 1Clinical Oral Physiology, Århus Univ., Aarhus, Denmark, 2Dept. of Dentistry & Oral Physiology, Sch. of Med., Keio Univ...

  7. Clinical significance of isometric bite force versus electrical activity in temporal and masseter muscles

    DEFF Research Database (Denmark)

    Bakke, Merete; Michler, L; Han, K

    1989-01-01

    Bite force and activity in temporal and masseter muscles during biting and chewing were recorded in 19 control subjects and 23 subjects with symptoms and signs of functional disorders of the craniomandibular system. The entire group comprised 13 men and 29 women, 14-63 yr of age. Maximal unilater...... of mandibular elevator strength as a whole, but inadequate to disclose asymmetric conditions. During isometric contraction, relative strength of electromyographic activity fairly accurately imaged the output of mechanical activity....

  8. Masseter length determines muscle spindle reflex excitability during jaw-closing movements.

    Science.gov (United States)

    Naser-Ud-Din, Shazia; Sowman, Paul F; Sampson, Wayne J; Dreyer, Craig W; Türker, Kemal Sitki

    2011-04-01

    The masticatory muscles are considered to be important determinants of facial form, but little is known of the muscle spindle reflex characteristics and their relationship, if any, to face height. The aim of this study was to determine whether spindle reflexes, evoked by mechanical stimulation of an incisor and recorded on the masseter muscle, correlated with different facial patterns. Twenty-eight adult volunteers (16 women; ages, 19-38 years) underwent 2-N tap stimuli to their maxillary left central incisor during simulated mastication. Reflexes were recorded during local anesthesia of the stimulated tooth to eliminate the contribution from periodontal mechanoreceptors. Surface electromyograms of the reflex responses of the jaw muscles to these taps were recorded via bipolar electrodes on the masseter muscle and interpreted by using spike-triggered averaging of the surface electromyograms. Lateral cephalometric analysis was carried out with software (version 10.5, Dolphin, Los Angeles, Calif; and Mona Lisa, Canberra, Australia). Two-newton tooth taps produced principally excitatory reflex responses beginning at 17 ms poststimulus. Correlation analysis showed a significant relationship between these muscle spindle reflexes and facial heights: specifically, shorter face heights were associated with stronger spindle reflexes. This correlation was strongest between the derived measure of masseter length and the spindle reflex strength during jaw closure (r = -0.49, P = 0.008). These results suggest that a similar muscle spindle stimulus will generate a stronger reflex activation in the jaw muscles of patients with shorter faces compared with those with longer faces. This finding might help to explain the higher incidence of clenching or bruxism in those with short faces and also might, in the future, influence the design of orthodontic appliances and dental prostheses. Copyright © 2011 American Association of Orthodontists. Published by Mosby, Inc. All rights

  9. Comparative study of excitation patterns in the masseter muscle before and after orthognathic surgery.

    Science.gov (United States)

    Eckardt, L; Harzer, W; Schneevoigt, R

    1997-12-01

    This study was designed to inquire into changes occurring in the electromyographic activity throughout the masseter muscle after orthognathic surgical treatment of various bite anomalies. A total of 32 adult patients showing distinct class II (n = 15) or class III malocclusions (n = 17) were entered into the investigation. All patients had monopolar surface electromyograms of the masseter muscle taken prior to presurgical orthodontic treatment and after removal of their orthodontic appliances after surgery. Twenty eugnathic adult patients served as controls. Unlike bipolar lead readings, simultaneous sampling from 16 electrodes permits the registration of the overall excitation pattern in the entire muscle. Recordings were taken during clenching, chewing and protrusion of the lower jaw against a defined force. Comparison with preoperative EMGs proved postsurgical distribution of excitation in class 11 patients to approximate the excitation pattern of eugnathic patients. By contrast, correction in class III malocclusions produced a shift in excitation maxima in the sense of a cranial advance. Harmonization, as evident in class II patients, did not occur. The postoperative discords in masseter excitation patterns, as observed after correction of class III anomalies, are indicative of the risk of relapse and the prolonged phase of retention associated with these conditions.

  10. Fiber-type differences in masseter muscle associated with different facial morphologies

    Science.gov (United States)

    Rowlerson, Anthea; Raoul, Gwénaël; Daniel, Yousif; Close, John; Maurage, Claude-Alain; Ferri, Joel; Sciote, James J.

    2013-01-01

    Background The influence of muscle forces and associated physiologic behaviors on dental and skeletal development is well recognized but difficult to quantify because of the limited understanding of the interrelationships between physiologic and other mechanisms during growth. Methods The purpose of this study was to characterize fiber-type composition of masseter muscle in 44 subjects during surgical correction of malocclusion. Four fiber types were identified after immunostaining of biopsy sections with myosin heavy chain-specific antibodies, and the average fiber diameter and percentage of muscle occupancy of the fiber types were determined in each of 6 subject groups (Class II or Class III and open bite, normal bite, or deepbite). A 2 × 3 × 4 analysis of variance was used to determine significant differences between mean areas for fiber types, vertical relationships, and sagittal relationships. Results There were significant differences in percentage of occupancy of fiber types in masseter muscle in bite groups with different vertical dimensions. Type I fiber occupancy increased in open bites, and conversely, type II fiber occupancy increased in deepbites. The association between sagittal jaw relationships and mean fiber area was less strong, but, in the Class III group, the average fiber area was significantly different between the open bite, normal bite, and deepbite subjects. In the Class III subjects, type I and I/II hybrid fiber areas were greatly increased in subjects with deepbite. Conclusions Given the variation between subjects in fiber areas and fiber numbers, larger subject populations will be needed to demonstrate more significant associations between sagittal relationships and muscle composition. However, the robust influence of jaw-closing muscles on vertical dimension allowed us to conclude that vertical bite characteristics vary according to the fiber type composition of masseter muscle. PMID:15643413

  11. Haemodynamic changes in human masseter and temporalis muscles induced by different levels of isometric contraction.

    Science.gov (United States)

    Kim, Y J; Kuboki, T; Tsukiyama, Y; Koyano, K; Clark, G T

    1999-08-01

    This study evaluated the influence of low contraction forces on intramuscular haemodynamics in human masseter and temporalis using near-infrared tissue spectroscopy. This method allowed the intramuscular haemoglobin (Hb) to be assessed dynamically before, during and after a 5, 15, 25 and 100% maximum voluntary contraction (MVC). Twenty volunteers, 10 males and 10 females, without pain or dysfunction in the masticatory system were included in this study. Data were recorded for 30 s before, 30 s during and 5 min after the four sustained contraction tasks. The results showed that all four levels of voluntary contraction produced a clear haemodynamic response (during and after contraction) in both muscles. For analytical purposes, the maximum Hb achieved after 100% MVC was set equal to 1.00. In the masseter the mean peak Hb during the 5, 15, 25 and 100% MVC was 0.49, 0.92, 1.30 and 1.73 while after the contractions it was 0.50, 0.65, 0.78 and 1.00, respectively. In the temporalis the peak Hb during the contractions was 0.23, 0.36, 0.48 and 0.66 and after the contractions 0.32, 0.45, 0.56 and 1.00, respectively. Repeated-measures analysis of variance revealed a significant main effect for the different contraction levels both in the masseter (during contraction, p = 0.001; after contraction, parchitecture between the two muscles contributes to these differences in blood flow.

  12. The influence of the type of contraction on the masseter muscle EMG power spectrum.

    Science.gov (United States)

    Nadeau, S; Bilodeau, M; Delisle, A; Chmielewski, W; Arsenault, A B; Gravel, D

    1993-01-01

    Different behaviours of the EMG power spectrum across increasing force levels have been reported for the masseter muscle. A factor that could explain these different behaviours may be the type of contraction used, as was recently shown for certain upper limb muscles(5). The purpose of this study was to compare, between two types of isometric contractions, the behaviour of EMG power spectrum statistics (median frequency (MF) and mean power frequency (MPF)) obtained across increasing force levels. Ten women exerted, while biting in the intercuspal position, three 5 s ramp contractions that increased linearly from 0 to 100% of the maximal voluntary contraction (MVC). They also completed three step contractions (constant EMG amplitude) at each of the following levels: 20, 40, 60 and 80% MVC. EMG signals from the masseter muscle were recorded with miniature surface electrodes. The RMS, as well as the MPF and MF of the power spectrum were calculated at 20, 40, 60 and 80% MVC for each type of contraction. As expected, the RMS values showed similar increases with increasing levels of effort for both types of contractions. Different behaviours for both MPF (contraction(∗)force interaction, ANOVA, P0.05) across increasing levels of effort were found between the two types of contraction. The use of step contractions gave rise to a decrease of both MPF and MF with increasing force, while the use of ramp contractions gave rise to an increase in both statistics up to at least 40% MVC followed by a decrease at higher force levels. These findings suggest that the type of contraction used does influence the behaviour of the spectral statistics across increasing force levels and that this could explain the differences obtained in previous studies for the masseter muscle. Copyright © 1993. Published by Elsevier Ltd.

  13. Initial Presentation of Renal Cell Carcinoma as a Metastatic Mass within the Masseter Muscle: A Case Report and Literature Review

    Energy Technology Data Exchange (ETDEWEB)

    Bae, Kyung Eun; Lee, Han Bee; Cho, Woo Ho; Kim, Jae Hyung; Lee, Ji Hae; Kang, Min Jin [Dept. of Radiology, Sanggye Paik Hospital, Inje University College of Medicine, Seoul (Korea, Republic of); Kim, Hyun Jung [Dept. of Pathology, Sanggye Paik Hospital, Inje University College of Medicine, Seoul (Korea, Republic of)

    2012-02-15

    Renal cell carcinoma (RCC) is often concomitant with distant metastasis, and these metastases are the first sign of an otherwise occult primary. Whereas metastasis of RCC to the head and neck has been reported, metastasis to the masseter muscle, which is composed of skeletal muscle, is quite rare. We now report the case of a 66-year-old man who had a past history of pulmonary tuberculosis, with RCC metastasis of a well-defined intensely enhancing hypervascular mass in the masseter muscle as the initial presentation. We present the imaging findings of this case and a literature review about radiologic differential diagnosis of intramasseteric masses.

  14. Cold pressor stimulus temperature and resting masseter muscle haemodynamics in normal humans.

    Science.gov (United States)

    Maekawa, K; Kuboki, T; Clark, G T; Shinoda, M; Yamashita, A

    1998-11-01

    Cold pressor stimulation reportedly increases sympathetic nerve activity in human skeletal muscles. This study examined the effect of cold pressor stimulation on the resting haemodynamics of the right masseter muscle in normal individuals, using near-infrared spectroscopy. Nine healthy non-smoking males with no history of chronic muscle pain or vascular headaches participated. Their right hand was immersed in a water bath (4, 10, 15 degrees C) for exactly 1 min. Each trial lasted 7 min (1 min before, 1 min during, 5 min after stimulation) and a strictly random order was utilized for the three test temperatures and the mock trial. Masseter muscle haemoglobin concentration and oxygen saturation, as well as heart rate and blood pressure, were continuously recorded in each trial. After completing the four trials, each participant produced and sustained a 30-s maximum voluntary clench in the intercuspal position. Data across the four trials were baseline-corrected and then magnitude-normalized to the individual's highest absolute haemoglobin and oxygen signal during the 30-s maximal clenching effort. Haemoglobin and oxygen saturation increased progressively during cold pressor stimulation as the water temperature decreased (Hb, p cold pressor, stimulation induces a strong increase in intramuscular blood volume which appears to be due to both a local vasodilative response and increased cardiac output.

  15. Ultrasonographic assessment of the swelling of the human masseter muscle after static and dynamic activity

    DEFF Research Database (Denmark)

    Bakke, M; Thomsen, C E; Vilmann, A

    1996-01-01

    Work-related fatigue, pain and disorders in skeletal muscles have been related to prolonged static and dynamic activity. Such contractions have been shown to impair blood flow and increase muscle thickness and fluid. In the present study the effect of static and dynamic activity was evaluated from...... changes in masseter thickness as a measure of oedema, simultaneously with assessment of perceived pain/discomfort and cardiovascular responses. As static activity, fourteen young healthy women bit at 15% maximal voluntary contraction on bite-force transducers in the molar regions until exhaustion or 20.......5%) than dynamic activity (4.3%), whereas heart rate rose significantly only during dynamic exercise (13.3%). Hence, activity was associated with muscular swelling and pain, and, despite the relatively small size of the masticatory muscles, also with general cardiovascular responses....

  16. Evaluation of the masseter muscle elasticity with the use of acoustic coupling agents as references in strain sonoelastography.

    Science.gov (United States)

    Nakayama, M; Ariji, Y; Nishiyama, W; Ariji, E

    2015-01-01

    To verify the use of a single coupling agent as a reference to obtain the elasticity index (EI) ratios and to investigate the EI ratios of the masseter muscles of healthy volunteers. Muscle phantoms with known elasticity (20, 40 and 60 kPa in the Young's modulus) were examined by strain-type sonoelastography using a coupling agent as the reference. Eight examiners tested soft (with 7 kPa) and hard (with 40 kpa) reference coupling agents separately. The correlation coefficients were determined between the EI ratio and Young's modulus of muscle phantoms. The interclass correlation coefficients were calculated for inter- and intraexaminer agreement. Strong correlations were found between the EI ratios and Young's modulus for both soft and hard references. The variations of the EI ratios were larger with soft coupling agents than those with hard coupling agents, and they increased in phantoms with 60 kPa elasticity. There were no differences in the EI ratios of the masseter muscle at rest between males and females or between the right and left sides. The ratio increased during clenching. The hard reference coupling agent was suitable for obtaining EI ratio of the masseter muscle. No differences were found in the EI ratios of the masseter muscle either between sexes or between the right and left sides at rest, and the ratios increased with the widening of their variations during clenching.

  17. EMG power spectrum and motor unit characteristics in the masseter muscle of the rabbit.

    Science.gov (United States)

    Turkawski, S J; van Eijden, T M

    2000-04-01

    Masticatory muscles contain a large variety of motor units with different physiological and morphological properties. In this study, we tested the hypothesis that a relationship exists between the mechanical and myo-electric properties of single motor units in the masseter muscle of the rabbit. It was expected that faster-contracting motor units, which usually have a relatively large number of fibers with large diameters, should have faster action potentials with larger amplitudes than slower motor units. Single motor units were stimulated. A two-dimensional force transducer registered mechanical parameters of the units. EMG electrodes were used to determine amplitude and frequency parameters of the action potentials of the same units. The results showed that faster-contracting motor units indeed produced action potentials with higher conduction velocities. However, faster motor units had no significant larger amplitude of the action potential. Small but significant positive correlations were found between the tetanic peak force and the amplitude of the action potentials. Little difference was found among the various frequency and amplitude parameters, respectively, making them equally suitable to describe the action potential. Surprisingly, a negative correlation between the amplitude and frequency parameters of the action potential was found, which may result from variability in arrival times of action potentials at the electrode site. Regional differences in the frequency parameters were found between the anterior and posterior parts of the superficial masseter.

  18. [Motor unit activities of human masseter muscle during sustained voluntary contractions].

    Science.gov (United States)

    Shimizu, T

    1990-02-01

    The purpose of this paper is to investigate the motor unit activities of the human masseter muscle during sustained the bite force at a constant level. The electrical activities recorded with surface and inserted electrodes were studied, with the following results. 1. The masseter muscle had the changes of activities in two phases as a contraction progressed. 2. In the first phase, surface EMG activities decreased and discharge frequency of motor units also decreased. 3. In the second phase, surface EMG activities increased and discharge frequency of motor units also increased. 4. In the first phase, it was suggested that the bite force was maintained by an increase in the twitch tension produced by a motor unit and that there were no recruitment of additional motor units. 5. In the second phase, it was indicated that the bite force was maintained by the recruitment of new motor units and an increase in the discharge frequency of motor units to compensate a loss of force resulted from the contractile element fatigue.

  19. Electromyographic biofeedback training for reducing muscle pain and tension on masseter and temporal muscles: A pilot study.

    Science.gov (United States)

    Criado, Laura; de La Fuente, Antonio; Heredia, Margarita; Montero, Javier; Albaladejo, Alberto; Criado, José-María

    2016-12-01

    Due to the absence of agreement about an effective unified treatment for temporomandibular disorders, non-invasive therapies such as EMG-biofeedback generate a greater interest. Furthermore, most studies to the present show methodological deficiencies that must be solved in the future, which makes important to emphasize this line of studies. Fourteen patients were selected for this case series study, and replied to a questionnaire concerning awareness of bruxism, painful muscles, and muscle tension. They also practiced an intraoral exploration (occlusal analysis and mandibular dynamics), and an extraoral exploration of the head and neck muscles and the temporomandibular joint. Before each session, patients responded to a questionnaire about the subjective perceived improvement. In each session, a period of three minutes of pre-biofeedback EMG activity of right masseter and temporal muscles was registered, then patients performed 30 iterations of visual EMG-biofeedback training and finally, a period of three minutes of post-EMG activity was also registered for those muscles. Patients performed four sessions. A decrease in painful symptoms was found for all patients since the first session. EMG activity decreases (pmuscles during the biofeedback training stage, in the four sessions. It is also observed a decrease (pmuscle at the post-biofeedback stage, in the second and third sessions. There is likewise a decrease in EMG post-biofeedback activity of the temporal muscle (pmuscles during the session. This decrease persists during the post-biofeedback period since the second session. Also there is a decrease in painful symptoms for all patients. Key words:Muscle tension, muscle pain, EMG-biofeedback, masseter muscle, temporal muscle.

  20. [Relationship between jaws and the masseter muscle by superimposing MR images on the cephalogram].

    Science.gov (United States)

    Higashino, Ryoji

    2006-03-01

    The purpose of this study was to observe the morphological relationship between maxillofacial skeleton and masseter by superimposing the masseter image constructed by MR image scanning on the cephalogram. Sixteen subjects with different mandibular plane angle were examined in this study. Cephalogram and MR images of each subject were taken, and the images were input to a computer by using a digitizer. The areas of masseter were selected in each MR scan image which were projected to the mid-sagittal layer of the MR scan images. The synthesized image of cephalogram and masseter was obtained by completely superimposing sagittal images of the masseter with the mid-sagittal-plane MR image on the cephalogram. The inclination of masseter was determined by the center of gravity on the cross-section of masseter. These synthesized images of cephalogram and masseter showed various shapes of masseter according to different mandibular plane angle. The inclination of masseter had a close correlation with some skeletal parameters (mandibular plane angle, ANB, Y-axis, facial angle, saddle angle) of cephalometric analysis. The volume of the masseter also had a close correlation with skeletal parameters (mandibular plane angle, gonial angle, Y-axis). These results revealed that morphometric analysis using synthesized images of cephalogram and masseter is useful, and that the inclination and the volume of masseter may have an influence on the shape of the mandibular bone and its vertical and anteroposterior development.

  1. Sarcoglycan complex in masseter and sternocleidomastoid muscles of baboons: an immunohistochemical study

    Directory of Open Access Journals (Sweden)

    G. Cutroneo

    2015-06-01

    Full Text Available The sarcoglycan complex consists of a group of single-pass transmembrane glycoproteins that are essential to maintain the integrity of muscle membranes. Any mutation in each sarcoglycan gene causes a series of recessive autosomal dystrophin-positive muscular dystrophies. Negative fibres for sarcoglycans have never been found in healthy humans and animals. In this study, we have investigated whether the social ranking has an influence on the expression of sarcoglycans in the skeletal muscles of healthy baboons. Biopsies of masseter and sternocleidomastoid muscles were processed for confocal immunohistochemical detection of sarcoglycans. Our findings showed that baboons from different social rankings exhibited different sarcoglycan expression profiles. While in dominant baboons almost all muscles were stained for sarcoglycans, only 55% of muscle fibres showed a significant staining. This different expression pattern is likely to be due to the living conditions of these primates. Sarcoglycans which play a key role in muscle activity by controlling contractile forces may influence the phenotype of muscle fibres, thus determining an adaptation to functional conditions. We hypothesize that this intraspecies variation reflects an epigenetic modification of the muscular protein network that allows baboons to adapt progressively to a different social status.

  2. Sarcoglycan complex in masseter and sternocleidomastoid muscles of baboons: an immunohistochemical study.

    Science.gov (United States)

    Cutroneo, G; Centofanti, A; Speciale, F; Rizzo, G; Favaloro, A; Santoro, G; Bruschetta, D; Milardi, D; Micali, A; Di Mauro, D; Vermiglio, G; Anastasi, G; Trimarchi, F

    2015-06-05

    The sarcoglycan complex consists of a group of single-pass transmembrane glycoproteins that are essential to maintain the integrity of muscle membranes. Any mutation in each sarcoglycan gene causes a series of recessive autosomal dystrophin-positive muscular dystrophies. Negative fibres for sarcoglycans have never been found in healthy humans and animals. In this study, we have investigated whether the social ranking has an influence on the expression of sarcoglycans in the skeletal muscles of healthy baboons. Biopsies of masseter and sternocleidomastoid muscles were processed for confocal immunohistochemical detection of sarcoglycans. Our findings showed that baboons from different social rankings exhibited different sarcoglycan expression profiles. While in dominant baboons almost all muscles were stained for sarcoglycans, only 55% of muscle fibres showed a significant staining. This different expression pattern is likely to be due to the living conditions of these primates. Sarcoglycans which play a key role in muscle activity by controlling contractile forces may influence the phenotype of muscle fibres, thus determining an adaptation to functional conditions. We hypothesize that this intraspecies variation reflects an epigenetic modification of the muscular protein network that allows baboons to adapt progressively to a different social status.

  3. Body position effects on EMG activity of sternocleidomastoid and masseter muscles in patients with myogenic cranio-cervical-mandibular dysfunction.

    Science.gov (United States)

    Palazzi, C; Miralles, R; Soto, M A; Santander, H; Zuñiga, C; Moya, H

    1996-07-01

    This study was conducted in order to determine the effects of body position on integrated electromyographic (IEMG) activity of sternocleidomastoid and masseter muscles in 17 patients with myogenic cranio-cervical-mandibular dysfunction. EMG recordings at rest and during swallowing of saliva and maximal voluntary clenching were performed by placing surface electrodes on the sternocleidomastoid and masseter muscles (contralateral to the habitual side of sleeping of each patient), in the following body positions: standing, seated, supine, and lateral decubitus position. Significant higher EMG activities were recorded in the sternocleidomastoid muscle in the lateral decubitus position and in the supine position (except during swallowing), whereas a significant higher EMG activity was recorded in the masseter muscle during maximal voluntary clenching in standing and seated positions. The EMG pattern observed suggests that the presence of parafunctional habits and body position could be closely correlated with the clinical symptomatology in the sternocleidomastoid and masseter muscles at wakening and during waking hours, respectively, in patients with myogenic cranio-cervical-mandibular dysfunction.

  4. Muscle response to the twin-block appliance: an electromyographic study of the masseter and anterior temporal muscles.

    Science.gov (United States)

    Aggarwal, P; Kharbanda, O P; Mathur, R; Duggal, R; Parkash, H

    1999-10-01

    An electromyographic study was performed on 10 young growing girls in the age group of 9 to 12 years with Class II Division 1 malocclusion and retruded mandible, who were under treatment with Twin-block appliances. Bilateral EMG activity of elevator muscles of the mandible (ie, anterior temporalis and masseter) was monitored longitudinally with bipolar surface electrodes to determine changes in postural, swallowing, and maximal voluntary clenching activity during an observation period of 6 months. The changes were noted at the start of treatment (0 month), within 1 month of Twin-block insertion, at the end of 3 months, and at the end of 6 months. The results revealed a significant increase in postural and maximal clenching EMG activity in masseter (P <.01) and a numeric increase in anterior temporalis activity during the 6 month period of treatment. The increased electromyographic activity can be attributed to an enhanced stretch (myotatic) reflex of the elevator muscles, contributing to isometric contractions. The main force for Twin-block treatment appears to be provided through increased active tension in the stretched muscles (motor unit stimulation) and from initiation of myotatic reflex activity and not through passive tension (viscoelastic properties) of jaw muscles. The results of this study reaffirm the importance of full-time wear for functional appliances to exert their maximum therapeutic effect by way of neuromuscular adaptation.

  5. Positional changes of the masseter and medial pterygoid muscles after surgical mandibular advancement procedures: an MRI study

    NARCIS (Netherlands)

    Dicker, G.J.; Koolstra, J.H.; Castelijns, J.A.; van Schijndel, R.A.; Tuinzing, D.B.

    2012-01-01

    This study evaluated whether surgical mandibular advancement procedures induced a change in the direction and the moment arms of the masseter (MAS) and medial pterygoid (MPM) muscles. Sixteen adults participated in this study. The sample was divided in two groups: Group I (n = 8) with a mandibular

  6. EMG Activity of Masseter Muscles in the Elderly According to Rheological Properties of Solid Food.

    Science.gov (United States)

    Kang, Au Jin; Kim, Don-Kyu; Kang, Si Hyun; Seo, Kyung Mook; Park, Hyoung Su; Park, Ki-Hwan

    2016-06-01

    To assess the impact of aging on masticatory muscle function according to changes in hardness of solid food. Each of fifteen healthy elderly and young people were selected. Subjects were asked to consume cooked rice, which was processed using the guidelines of the Universal Design Foods concept for elderly people (Japan Care Food Conference 2012). The properties of each cooked rice were categorized as grade 1, 2, 3 and 4 (5×10(3), 2×10(4), 5×10(4), and 5×10(5) N/m(2)) respectively. Surface electromyography (sEMG) was used to measure masseter activity from food ingestion to swallowing of test foods. The raw data was normalized by the ratio of sEMG activity to maximal voluntary contraction and compared among subjects. The data was divided according to each sequence of mastication and then calculated within the parameters of EMG activities. Intraoral tongue pressure was significantly higher in the young than in the elderly (psEMG data of the masseter can provide valuable information to aid in the selection of foods according to hardness for the elderly. The results also support the necessity of specialized food preparation or products for the elderly.

  7. Reproducibility of surface EMG in the human masseter and anterior temporalis muscle areas.

    Science.gov (United States)

    Castroflorio, Tommaso; Icardi, Katia; Torsello, Ferruccio; Deregibus, Andrea; Debernardi, Cesare; Bracco, Pietro

    2005-04-01

    The aim of this study was to test the hypothesis that surface electromyography (sEMG) recordings, made at mandibular rest position from the masseter and temporalis anterior areas, are intra- and inter-session reproducible. A template was designed and built to permit the correct electrode placement from one session to the next session. A sample of 18 subjects was examined. Two groups, homogeneous for age, sex, and craniofacial morphology were selected. The first group included asymptomatic subjects with no signs or symptoms of temporomandibular joint dysfunction (TMD) and the second group included patients suffering from muscle-related TMD. Data were obtained from different sEMG recordings made at mandibular rest position in the same session and in different sessions, repositioning the electrodes using a template designed for that purpose. The electromyograph used in this, study is part of the EMG K6-I Win Diagnostic System. Results showed that reproducibility of sEMG signals from the masseter and anterior temporalis areas at mandibular rest position is possible.

  8. Electromyographic analysis of the masseter and temporal muscles in oralized deaf individuals.

    Science.gov (United States)

    Regalo, S C H; Vitti, M; Semprini, M; Rosa, L B; Martinez, F H R M; Santos, C M; Hallak, J E C

    2006-01-01

    Deaf individuals show a number of difficulties related to the functionality of the stomatognathic system, mainly by reason of the little or no use of facial musculature during speech either due to the use of sign language or to the difficulty that these individuals have in articulating words. The stomatognathic system muscles play important roles in functions such as mastication, deglutition, and phonation. This study aimed to assess, by means of computerized bilateral electromyography (EMG), masseter and temporal muscles of 12 oralized deaf individuals in clinical activities that involve part of this masticatory musculature and compare this system's functionality with that of 12 normal listening individuals, performing the same activities. An 8-channel K6-I EMG Light Channel Surface Electromyography device was used (Myo-Tronics Co.Seattle, WA, USA), in addition to disposable double electrodes covered with silver chloride (Duotrodes; Myo-tronics Co., Seattle, WA) containing a conductor gel (Myogel- Myo-tronics Co., Seatlle, WA). The averaged rectified EMG values were normalized with reference to the EMG amplitude induced by a maximum bite force. The statistical analysis confirmed that there were any significant differences between the groups, clinical activities, and muscles, and also effects of interaction among them. The analysis made use of Variance Analysis (ANOVA). Significant differences (p masseter and temporal muscular activity such as mastication, mouth opening and closing, and dental compression. Greater electromyographic values were found for both deaf individuals and healthy controls during clinical activities of mastication and dental compression. Based on the obtained data, we concluded that deaf individuals showed a lower activity of the masticatory musculature than healthy individuals; the differences were significant at the level of p < 0.01 between the performed clinical activities; and all deaf individuals and healthy controls showed greater

  9. Three-dimensional CT might be a potential evaluation modality in correction of asymmetrical masseter muscle hypertrophy by botulinum toxin injection.

    Science.gov (United States)

    No, Yeon A; Ahn, Byeong Heon; Kim, Beom Joon; Kim, Myeung Nam; Hong, Chang Kwon

    2016-01-01

    For correction of this asymmetrical hypertrophy, botulinum toxin type A (BTxA) injection is one of convenient treatment modalities. Unfortunately, physical examination of masseter muscle is not enough to estimate the exact volume of muscle hypertrophy difference. Two Koreans, male and female, of bilateral masseter hypertrophy with asymmetricity were evaluated. BTxA (NABOTA(®), Daewoong, Co. Ltd., Seoul, Korea) was injected at master muscle site with total 50 U (25 U at each side) and volume change was evaluated with three-dimensional (3D) CT image analysis. Maximum reduction of masseter hypertrophy was recognized at 2-month follow-up and reduced muscle size started to restore after 3 months. Mean reduction of masseter muscle volume was 36% compared with baseline. More hypertrophied side of masseter muscle presented 42% of volume reduction at 2-month follow-up but less hypertrophied side of masseter muscle showed 30% of volume shrinkage. In conclusion, 3D CT image analysis might be the exact evaluation tool for correction of asymmetrical masseter hypertrophy by botulinum toxin injection.

  10. Frequency analyses of EMG power spectra of anterior temporal and masseter muscles in children and adults.

    Science.gov (United States)

    Takarada, T; Larrinaga, G A; Nishida, F; Nishino, M

    1990-01-01

    To study the functional change of masticatory muscles during growth and development, frequency analyses of surface electromyogram (EMG) power spectra were carried out. The subjects were six children (five males and one female), aged 4.5 +/- 0.2 years, having full deciduous dentition (Hellman's dental age IIA) and six adults (four males and two females), aged 27.7 +/- 3.8 years, having full permanent dentition. EMG signals were recorded bilaterally by using bipolar silver-surface electrodes from the anterior temporal and masseter muscles while the subjects were chewing gum and while performing maximum clenching in the intercuspal position. A fast Fourier transform algorithm was used to obtain the power-spectral density function and the power spectra of the EMG signals. Since the total power value from 62.5 to 1000 Hz was 100 percent, the frequencies at 25, 50, 75, and 90 percent of the cumulative power were calculated. The results showed that the frequencies at every percent of the cumulative power were age-dependent and that the EMG power spectra patterns in adult muscles were shifted to significantly lower frequencies than those in child muscles. The shift was probably caused by differences in the proportion of fiber type and fiber size between muscles of children and adults.

  11. The role of masseter muscle EMG during DISE to predict the effectiveness of MAD: preliminary results.

    Science.gov (United States)

    Marchese, M R; Scarano, E; Rizzotto, G; Grippaudo, C; Paludetti, G

    2016-12-01

    The use of a mandibular advancement device (MAD) increases the activity of the temporo-mandibular (TM) complex and masseter (MM) muscles with the risk of reducing treatment compliance. Predictors of treatment outcome are of importance in selecting patients who might benefit from MAD without side effects. The role of mandibular advancement (MA) during drug-induced sleep endoscopy (DISE) is controversial. In three cases (BMI DISE. At follow-up all cases improved the AHI, two cases that showed transient increase of MM activity did not suffer from changes of overjet and did not complain of discomfort with the use of MAD. The case that showed a continuing increase of MM activity reported TM discomfort without changes of dental occlusion. EMG of MM during DISE may contribute to ameliorate the selection of cases amenable to treatment with MAD.

  12. Masseter muscle tension, chewing ability, and selected parameters of physical fitness in elderly care home residents in Lodz, Poland

    Directory of Open Access Journals (Sweden)

    Gaszynska E

    2014-07-01

    Full Text Available Ewelina Gaszynska,1 Malgorzata Godala,2 Franciszek Szatko,1 Tomasz Gaszynski3 1Department of Hygiene and Health Promotion, Medical University of Lodz, Poland; 2Department of Nutrition and Epidemiology, Medical University of Lodz, Poland; 3Department of Emergency Medicine and Disaster Medicine, Medical University of Lodz, Poland Background: Maintaining good physical fitness and oral function in old age is an important element of good quality of life. Disability-related impairment of oral function contributes to a deterioration of the diet of older people and to the reduction of their social activity.Objectives: Investigate the association between masseter muscle tension, dental status, and physical fitness parameters.Materials and methods: Two hundred fifty-nine elderly care home residents (97 men, 162 women; mean age, 75.3±8.9 years were involved in this cross-sectional study. Their chewing ability was evaluated by masseter muscle tension palpation, differences of masseter muscle thickness, self-reported chewing ability, number of present and functional teeth, and number of posterior tooth pairs. Masseter muscle thickness was measured by ultrasonography. To assess physical fitness, hand grip strength and the timed up-and-go test were performed. Nutritional status was assessed using body mass index and body cell mass index (BCMI, calculated on the basis of electrical bioimpedance measurements. Medical records were used to collect information on systemic diseases and the number of prescribed medications. Subjects were also evaluated for their ability to perform ten activities of daily living.Results: Ninety-seven percent of the subjects suffered from systemic diseases. The three most prevalent illnesses were cardiac/circulatory 64.5%, musculoskeletal 37.3%, and endocrine/metabolic/nutritional 29.3%. Of the participants, 1.5% were underweight and more than one third (34.4% were overweight. Malnutrition (BCMI below normal was found in almost

  13. Effect of experimental jaw-muscle pain on the spatial distribution of surface EMG activity of the human masseter muscle during tooth clenching.

    Science.gov (United States)

    Castroflorio, T; Falla, D; Wang, K; Svensson, P; Farina, D

    2012-02-01

    This study tested the hypothesis that painful injections of glutamate into the human masseter muscle differentially affect the distribution of the electromyographic (EMG) activity in the masseter muscle at rest and during tooth clenching. Surface EMG signals were recorded bilaterally from the superficial masseter of nine healthy men with a grid of 32 electrodes, before and after intramuscular injection of glutamate or isotonic saline, during rest and isometric contractions at 20%, 40%, 60% and 80% of the maximal voluntary bite force. Intramuscular injection of glutamate evoked moderate pain (0-10 visual analogue scale: 6·4 ± 1·4), with sensory-discriminative characteristics of the perceived pain, evaluated with the use of the McGill Pain Questionnaire (MPQ), similar to those previously reported for patients with temporomandibular disorders. There was no effect of the glutamate injection on EMG amplitude during rest, whereas during tooth clenching, the spatial distribution of the masseter EMG activity on both sides was more uniform in the painful condition compared to the control condition. Moreover, the overall EMG amplitude decreased on both sides during the more forceful tooth clenching following glutamate injection. In conclusion, a unilateral painful stimulation was associated with a bilateral inhibition of the masseter muscles during tooth clenching which resulted in a more uniform distribution of EMG activity. © 2011 Blackwell Publishing Ltd.

  14. Effect of botulinum toxin type A injection into human masseter muscle on stimulated parotid saliva flow rate.

    Science.gov (United States)

    Kwon, J S; Kim, S T; Jeon, Y M; Choi, J H

    2009-04-01

    Botulinum toxin type A (BTX-A) injection into the masseter muscles is used to treat masseteric hypertrophy. No serious side effects of BTX-A have been reported, but patients sometimes complain of xerostomia. The aim of this study was to evaluate the effect of injecting BTX-A into the masseter for the treatment of masseteric hypertrophy on the flow of saliva from the parotid gland. 34 volunteers enrolled in this study. A total of 25 units of BTX-A was injected into each side bilaterally at two points at the center of the lower third of the masseter muscle. Saliva was collected from the parotid gland over a period of 10 min to determine the flow rate for 18 weeks after injection. The flow rate was calculated by dividing the amount in milliliters by the collection time in minutes. There were no significant changes in the stimulated parotid saliva flow at 4, 8, 12 or 18 weeks compared with the baseline. Within this limited study, it can be concluded that BTX-A injection into the masseter does not cause any significant decrease in the production of saliva from the parotid gland.

  15. [INVESTIATION OF ELECTROMYOGRAPHIC ACTIVITY OF TEMPORAL AND MASSETER MUSCLES AFTER ORTHODONTIC TREATMENT OF MALOCCLUSION COMPLICATED BY DENTAL CROWDING].

    Science.gov (United States)

    Dmitrenko, M I

    2014-01-01

    The results of investigation showed that it is necessary to use complex methods of orthodontic treatment in patients with malocclusion complicated by dental crowding. Orthodontic appliance therapy should be accompanied by differentiated massage and mioymnastics to improve functional state of masseter and temporal muscles. It was found that after the treatment electromyographic potential amplitude of temporal muscles is on the average in 1.5 times lower as compared with pretreatment records (P muscles during clenching after the treatment of maxillary and mandibular dental crowding (P muscles functional symmetry. During clenching index MASI(MM) significantly decreased in all groups in comparison with pretreatment indices (P < 0.05).

  16. The human masseter muscle and its biological correlates: A review of published data pertinent to face prediction.

    Science.gov (United States)

    Stephan, Carl N

    2010-09-10

    The masseter muscle forms a cornerstone of anatomical facial reconstruction (FR) methods, yet it is only scantily described in the FR literature despite relatively intense research focus from other disciplines. This suggests that much more data exists for masseter prediction than that which is currently used in FR. This paper reviews the masseter muscle and finds that highly pertinent anatomical and metric data to be available despite being overlooked in the FR literature. This includes variance and means of the perimeter dimensions, thicknesses, cross-sectional areas, volumes, metrics associated with muscle attachment, and correlations with other biological and craniometric variables (such as sex, age, tooth loss, cranial breadths, facial heights, alveolar thicknesses, and gonial angles). The oversight of these metric data adds to a general pattern seen for other hallmark structures of the face in FR and, taken together, these observations hold major ramifications for longstanding debates of FR accuracy, reliability, and error. Irrespectively, the data reviewed in this manuscript help set an improved basis for quantification of FR techniques. Published by Elsevier Ireland Ltd.

  17. SURFACE ELECTROMYOGRAPHY OF MASSETER AND TEMPORAL MUSCLES WITH USE PERCENTAGE WHILE CHEWING ON CANDIDATES FOR GASTROPLASTY.

    Science.gov (United States)

    Santos, Andréa Cavalcante Dos; Silva, Carlos Antonio Bruno da

    Surface electromyography identifies changes in the electrical potential of the muscles during each contraction. The percentage of use is a way to treat values enabling comparison between groups. To analyze the electrical activity and the percentage of use of masseter and temporal muscles during chewing in candidates for gastric bypass. It was used Surface Electromyography Miotool 200,400 (Miotec (r), Porto Alegre/RS, Brazil) integrated with Miograph 2.0 software, involving patients between 20-40 years old. Were included data on electrical activity simultaneously and in pairs of temporal muscle groups and masseter at rest, maximum intercuspation and during the chewing of food previously classified. Were enrolled 39 patients (59 women), mean age 27.1+/-5.7. The percentage of use focused on temporal muscle, in a range of 11-20, female literacy (n=11; 47.82) on the left side and 15 (65.21) on the right-hand side. In the male, nine (56.25) at left and 12 (75.00) on the right-hand side. In masseter, also in the range of 11 to 20, female literacy (n=10; 43.48) on the left side and 11 (47.83) on the right-hand side. In the male, nine (56.25) at left and eight (50.00) on the right-hand side. 40-50% of the sample showed electrical activity in muscles (masseter and temporal) with variable values, and after processing into percentage value, facilitating the comparison of load of used electrical activity between the group, as well as usage percentage was obtained of muscle fibers 11-20% values involving, representing a range that is considered as a reference to the group studied. The gender was not a variable. A eletromiografia de superfície identifica variações dos potenciais elétricos dos músculos durante cada contração realizada. O percentual de uso é uma forma de tratar valores possibilitando comparação entre grupos. Analisar a atividade elétrica e o percentual de uso dos músculos masséteres e temporais durante a mastigação em candidatos à gastroplastia

  18. The effect of a cholecystokinin agonist on masseter muscle activity in the cat.

    Science.gov (United States)

    Sitthisomwong, P; Weiner, S; Levin, L; Reisman, S; Siegel, A

    2000-10-01

    The CCK(B) agonist, pentagastrin, has been shown to induce anxiety in human subjects. Similarly, in the cat model, pentagastrin facilitates the expression of hypothalamically activated emotional behavior. Because hypothalamically mediated emotional behavior is also accompanied by increased EMG activity in the jaw muscles, these experiments were designed to examine the combined effects of administration of pentagastrin with activation of hypothalamically mediated emotional behavior upon jaw muscle EMG activity. Electrodes were carefully lowered through previously placed guide tubes overlying the hypothalamus until a behavioral site was identified. Following the establishment of a stable threshold current for eliciting an emotional behavioral response, the skin overlying the ipsilateral masseter muscle was shaved and cleaned with alcohol, and surface electrodes were attached. The EMG was recorded, amplified, digitized, and stored in a microcomputer for analysis. Mean power frequencies (MPF) and latencies for behavior were calculated for baseline prior to infusion of all drugs. Following this, the effects of intravenous administration of pentagastrin and the CCK(B) antagonist LY288513 on the MPF were determined. The infusion of the CCK(B) agonist, pentagastrin (0.77, 1.92, and 3.84 microg/kg), decreased MPF in a time-related manner. The effects of pentagastrin 1.92 microg/kg were blocked by the CCK(B) antagonist, LY288513 (6.54 microg/kg). In addition, the infusion of LY288513 alone increased MPF. These results are surprising in that pentagastrin's anxiogenic properties would appear to make it likely to facilitate motor activity, not suppress it.

  19. Illusion caused by vibration of muscle spindles reveals an involvement of muscle spindle inputs in regulating isometric contraction of masseter muscles.

    Science.gov (United States)

    Tsukiboshi, Taisuke; Sato, Hajime; Tanaka, Yuto; Saito, Mitsuru; Toyoda, Hiroki; Morimoto, Toshifumi; Türker, Kemal Sitki; Maeda, Yoshinobu; Kang, Youngnam

    2012-11-01

    Spindle Ia afferents may be differentially involved in voluntary isometric contraction, depending on the pattern of synaptic connections in spindle reflex pathways. We investigated how isometric contraction of masseter muscles is regulated through the activity of their muscle spindles that contain the largest number of intrafusal fibers among skeletal muscle spindles by examining the effects of vibration of muscle spindles on the voluntary isometric contraction. Subjects were instructed to hold the jaw at resting position by counteracting ramp loads applied on lower molar teeth. In response to the increasing-ramp load, the root mean square (RMS) of masseter EMG activity almost linearly increased under no vibration, while displaying a steep linear increase followed by a slower increase under vibration. The regression line of the relationship between the load and RMS was significantly steeper under vibration than under no vibration, suggesting that the subjects overestimated the ramp load and excessively counteracted it as reflected in the emergence of bite pressure. In response to the decreasing-ramp load applied following the increasing one, the RMS hardly decreased under vibration unlike under no vibration, leading to a generation of bite pressure even after the offset of the negative-ramp load until the vibration was ceased. Thus the subjects overestimated the increasing rate of the load while underestimating the decreasing rate of the load, due to the vibration-induced illusion of jaw opening. These observations suggest that spindle Ia/II inputs play crucial roles both in estimating the load and in controlling the isometric contraction of masseter muscles in the jaw-closed position.

  20. Study on the association of ultrasonographic thickness and electromyographic activity of masseter muscle in young females with different vertical craniofacial morphology.

    Science.gov (United States)

    Li, Hai-Tao; Cui, Chuan-Jiang; Lu, Shu-Lai; He, Kai-Yun

    2008-10-01

    To study the relationship between ultrasonographic thickness and EMG activity of the masseter muscle in subjects with different vertical craniofacial morphology. Thirty female students were separated into two groups (14 cases with high-angle, 16 cases with low-angle) based on SN-MP angle, FH-MP angle, and FHI. The thickness of the masseter muscle under relaxed conditions and during maximal clenching was assessed by ultrasonography. EMG activity of the masseter muscle under relaxed conditions and during maximal clenching was recorded with bipolar surface electrodes.All measurements were analyzed with SPSS 11.0 software package. Differences between groups were tested for statistical significance using Student's t test. The relationship between masseter muscle thickness and its EMG activity was estimated by Pearson's correlation coefficient. The thickness of the masseter muscle in the low-angle individuals was significantly greater than that in the high-angle individuals under relaxed conditions (P=0.009) and during maximal clenching (P=0.000). Although there was no significant difference in resting EMG activity between the two groups, the EMG activity of masseter muscle in the low-angle individuals was also significantly higher than that in the high-angle individuals during maximal clenching(P=0.022). Relaxed thickness of masseter muscle was significantly correlated with its mean maximum EMG activity in the low-angle group (r=0.61, P=0.003) and moderately correlated with that in the high-angle group (r=0.38, P=0.023). Similar correlation was found between contracted thickness of masseter muscle and the mean maximum EMG activity, being significantly correlated in the low-angle group (r=0.73, P=0.002) and moderately correlated in the high-angle group(r=0.53, P=0.006). The present findings support the concept that subjects with different vertical craniofacial morphology have different form and function of masseter muscle. The ultrasonographic thickness and EMG activity

  1. Compression-induced hyperaemia in the rabbit masseter muscle: a model to investigate vascular mechano-sensitivity of skeletal muscle.

    Science.gov (United States)

    Turturici, Marco; Roatta, Silvestro

    2013-03-01

    Recent evidence suggests that the mechano-sensitivity of the vascular network may underlie rapid dilatory events in skeletal muscles. Previous investigations have been mostly based either on in vitro or on whole-limb studies, neither preparation allowing one to assess the musculo-vascular specificity under physiological conditions. The aim of this work is to characterize the mechano-sensitivity of an exclusively-muscular vascular bed in vivo. In five anesthetized rabbits, muscle blood flow was continuously monitored in the masseteric artery, bilaterally (n = 10). Hyperaemic responses were evoked by compressive stimuli of different extent (50, 100 and 200 mm Hg) and duration (0.5, 1, 2 and 5 s) exerted by a servo-controlled motor on the masseter muscle. Peak amplitude of the hyperaemic response ranged from 340 ± 30% of baseline (at 50 mm Hg) to 459 ± 57% (at 200 mm Hg) (P < 0.05), did not depend on stimulus duration and exhibited very good reliability (ICC = 0.98) when reassessed at 30 min intervals. The time course of the response depended neither on applied pressure nor on the duration of the stimulus. In conclusion, for its high sensitivity and reliability this technique is adequate to characterize mechano-vascular reactivity and may prove useful in the investigation of the underlying mechanisms, with implications in the control of vascular tone and blood pressure in health and disease.

  2. Noninvasive estimation of the location of the end plate in the human masseter muscle using surface electromyograms with an electrode array.

    Science.gov (United States)

    Iwasaki, S; Tokunaga, T; Baba, S; Tanaka, M; Kawazoe, T

    1990-10-01

    The purpose of this study was to estimate the location of the end plate in the masseter muscle, and to decide the appropriate position of surface electrodes for recording electromyograms (EMG) in humans. The subjects were 16 males who had no signs or symptoms of muscular disease. Identical electrode arrays were placed on the masseter muscles on each side. Each subject was asked to clench in the intercuspal position at various levels of maximum EMG amplitude. Eleven amplified EMGs were monitored simultaneously using a linear electrode array consisting of 12 stainless steel contacts. Various values were observed in different regions of the masseter muscle for the root mean square rectified EMG during brief isometric contraction. The superior region of the muscle had lower values than the inferior. The end-plate zone, which is in the center of the lower half of the masseter muscle, showed a lower amplitude than other regions. The propagation of motor unit action potentials was also observed. It was concluded that, aside from the end-plate zone, a position within the lower half of the muscle was most suitable for recording the surface EMG of the masseter muscle.

  3. EMG, bite force, and elongation of the masseter muscle under isometric voluntary contractions and variations of vertical dimension.

    Science.gov (United States)

    Manns, A; Miralles, R; Palazzi, C

    1979-12-01

    The relation EMG activity, bite force, and muscular elongation was studied in eight subjects with complete natural dentition during isometric contractions of the masseter muscle, measured from 7 mm to almost maximum jaw opening. EMG was registered with superficial electrodes and bite force with a gnathodynamometer. In series 1, recordings of EMG activity maintaining bite force constant (10 and 20 kg) show that EMG is high when the bite opening is 7 mm, decreases from 15 to 20 mm, and then increases again as jaw opening approaches maximum opening. In series 2, recordings of bite force maintaining EMG constant show that bite force increases up to a certain range of jaw opening (around 15 to 20 mm) and then decreases as we approach maximum jaw opening. Results show that there is for each experimental subject a physiologically optimum muscular elongation of major efficiency where the masseter develops highest muscular force with least EMG activity.

  4. Short-term effects of dry needling of active myofascial trigger points in the masseter muscle in patients with temporomandibular disorders.

    Science.gov (United States)

    Fernández-Carnero, Josué; La Touche, Roy; Ortega-Santiago, Ricardo; Galan-del-Rio, Fernando; Pesquera, Jorge; Ge, Hong-You; Fernández-de-Las-Peñas, César

    2010-01-01

    To investigate the effects of dry needling over active trigger points (TrPs) in the masseter muscle in patients with temporomandibular disorders (TMD). Twelve females, aged 20 to 41 years old (mean = 25, standard deviation +/- 6 years) diagnosed with myofascial TMD were recruited. Each patient attended two treatment sessions on two separate days and received one intervention assigned in a random fashion, at each visit: deep dry needling (experimental) or sham dry needling (placebo) at the most painful point on the masseter muscle TrP. Pressure pain threshold (PPT) over the masseter muscle TrP and the mandibular condyle and pain-free active jaw opening were assessed pre- and 5 minutes postintervention by an examiner blinded to the treatment allocation of the subject. A two-way repeated-measures analysis of variance (ANOVA) with intervention as the between-subjects variable and time as the within-subjects variable was used to examine the effects of the intervention. The ANOVA detected a significant interaction between intervention and time for PPT levels in the masseter muscle (F = 62.5; P dry needling compared to the sham dry needling (P dry needling into active TrPs in the masseter muscle induced significant increases in PPT levels and maximal jaw opening when compared to the sham dry needling in patients with myofascial TMD.

  5. [Frequency analysis of the EMG power spectrum of the anterior temporal and masseter muscles in children and adults].

    Science.gov (United States)

    Takarada, T; Alvarado Larrinaga, G; Nishida, F; Nishino, M

    1989-01-01

    For the investigation of the functional change of the masticatory muscles along with growth and development, the frequency analysis of the EMG power spectrum was carried out. The subjects were 6 children (5 males and 1 female) with full deciduous dentition (Hellman's dental age IIA) aged 4.5 +/- 0.2 years and 6 adults (4 males and 2 females) with full permanent dentition aged 27.7 +/- 3.8 years. EMG signals were recorded bilaterally by means of bipolar silver surface electrodes from the anterior temporal and masseter muscles when the subjects were chewing chewing gum or performing maximum clenches in the intercuspal position. A fast Fourier transform (FFT) algorithm was used to obtain the power spectrum of the EMG signal. As the total power value from 62.5 to 1000 Hz was 100 per cent, the mean frequencies at 25, 50, 75 and 90 per cent of the cumulative power were calculated. The results were as follows: 1. The mean frequencies at each ratio of the cumulative power were age-dependent and EMG power spectrum patterns significantly shifted to lower frequencies in the muscles of the adults. 2. No statistically significant differences between the chewing and clenching, the anterior temporal and masseter muscle and the left and right side were observed in each group.

  6. Molecular Motor MYO1C, Acetyltransferase KAT6B and Osteogenetic Transcription Factor RUNX2 Expression in Human Masseter Muscle Contributes to Development of Malocclusion

    Science.gov (United States)

    Desh, Heather; Gray, S Lauren; Horton, Michael J; Raoul, Gwenael; Rowlerson, Anthea M; Ferri, Joel; Vieira, Alexandre R; Sciote, James J

    2014-01-01

    Objective Type I myosins are molecular motors necessary for glucose transport in the cytoplasm and initiation of transcription in the nucleus. Two of these, MYO1H and MYO1C, are paralogs which may be important in the development of malocclusion. The objective of this study was to investigate their gene expression in the masseter muscle of malocclusion subjects. Two functionally related proteins known to contribute to malocclusion were also investigated: KAT6B (a chromatin remodeling epigenetic enzyme which is activated by MYO1C) and RUNX2 (a transcription factor regulating osteogenesis which is activated by KAT6B). Design Masseter muscle samples and malocclusion classifications were obtained from orthognathic surgery subjects. Muscle was sectioned and immunostained to determine fiber type properties. RNA was isolated from the remaining sample to determine expression levels for the four genes by TaqMan® RT-PCR. Fiber type properties, gene expression quantities and malocclusion classification were compared. Results There were very significant associations (P<0.0000001) between MYO1C and KAT6B expressions. There were also significant associations (P<0.005) between RUNX2 expression and masseter muscle type II fiber properties. Very few significant associations were identified between MYO1C and masseter muscle fiber type properties. Conclusions The relationship between MYO1C and KAT6B suggests that the two are interacting in chromatin remodeling for gene expression. This is the nuclear myosin1 (NM1) function of MYO1C. A surprising finding is the relationship between RUNX2 and type II masseter muscle fibers, since RUNX2 expression in mature muscle was previously unknown. Further investigations are necessary to elucidate the role of RUNX2 in adult masseter muscle. PMID:24698832

  7. A intervenção fonoaudiológica no pós-operatório da hipertrofia benigna do músculo masseter The miofunctional oral intervention in the surgery treatment for the masseter muscle hipertrophy

    Directory of Open Access Journals (Sweden)

    Laura Davison Mangilli

    2006-04-01

    Full Text Available OBJETIVO: descrever a abordagem fonoaudiológica no pós-operatório de pacientes que realizaram correção cirúrgica da hipertrofia do músculo masseter. METODOLOGIA: foram coletados dados referentes à avaliação e ao tratamento fonoaudiológico de 4 prontuários de sujeitos de ambos os gêneros, com faixa etária entre 16 e 24 anos, com hipertrofia benigna do músculo masseter, tratados cirurgicamente. RESULTADOS: as principais queixas pós-cirúrgicas estiveram relacionadas à limitação da abertura da boca, à dor na região da cirurgia, à rigidez muscular e a estalo em região da ATM. A terapia fonoaudiológica baseou-se em orientação quanto à retirada de hábitos deletérios; termoterapia na região do músculo masseter; manipulação da musculatura envolvida extra e intrabucais; alongamento da musculatura facial e cervical; alavanca de abertura forçada de boca e exercícios de órgãos fonoarticulatórios. CONCLUSÕES: a terapia fonoaudiológica apresenta-se como uma possibilidade de complementação ao tratamento cirúrgico, na adequação da amplitude dos movimentos mandibulares, assim como na eliminação dos sintomas presentes no pós-cirúrgico e na conscientização dos hábitos deletérios, que são apontados pela literatura como possíveis fatores desencadeantes.AIM: the aim of this study was to describe miofunctional oral intervention in patients with Masseter muscle hipertrophy treated by surgery. METHODS: the sample consisted of 4 patients, male and female, with ages between 16 and 24 years, with Masseter muscle hipertrophy treated by surgery. RESULTS: the main complains on the postoperative were related to trismus, muscle rigidity, and clicking in the temporomandibular joint. The myofunctional oral therapy was based on orientation in the abnormal habits (bruxism, clenching elimination, hyperthermia induced in the masseter muscle, oral muscles massage, facial and cervical muscles stretching, miofunctional exercises and

  8. A COMPARATIVE-STUDY OF ELECTROMYOGRAMS OF THE MASSETER, TEMPORALIS, AND ANTERIOR DIGASTRIC MUSCLES OBTAINED BY SURFACE AND INTRAMUSCULAR ELECTRODES - RAW-EMG

    NARCIS (Netherlands)

    KOOLE, P; DEJONGH, HJ; BOERING, G

    Electromyographic activity was synchronously recorded by surface and intramuscular electrodes in the same muscle. The activity of the left masseter, left temporalis, and both bellies of the anterior digastric muscle was studied by this double registration technique. In rest position no

  9. Muscle-specific integrins in masseter muscle fibers of chimpanzees: an immunohistochemical study.

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    Gianluigi Vaccarino

    2010-05-01

    Full Text Available Most notably, recent comparative genomic analyses strongly indicate that the marked differences between modern human and chimpanzees are likely due more to changes in gene regulation than to modifications of the genes. The most peculiar aspect of hominoid karyotypes is that human have 46 chromosomes whereas gorillas and chimpanzees have 48. Interestingly, human and chimpanzees do share identical inversions on chromosome 7 and 9 that are not evident in the gorilla karyotype. Thus, the general phylogeny suggests that humans and chimpanzees are sister taxa; based on this, it seems that human-chimpanzee sequence similarity is an astonishing 99%. At this purpose, of particular interest is the inactivation of the myosin heavy chain 16 (MYH16 gene, most prominently expressed in the masticatory muscle of mammals. It has been showed that the loss of this gene in humans may have resulted in smaller masticatory muscle and consequential changes to cranio-facial morphology and expansion of the human brain case. Powerful masticatory muscles are found in most primates; contrarily, in both modern and fossil member Homo, these muscles are considerably smaller. The evolving hominid masticatory apparatus shifted towards a pattern of gracilization nearly simultaneously with accelerated encephalization in early Homo. To better comprehend the real role of the MYH16 gene, we studied the primary proteins present in the muscle fibers of humans and non-humans, in order to understand if they really can be influenced by MYH16 gene. At this aim we examined the muscle-specific integrins, alpha 7B and beta 1D-integrins, and their relative fetal isoforms, alpha 7A and beta 1A-integrins, analyzing, by immunohistochemistry, muscle biopsies of two components of a chimpanzee's group in captivity, an alpha male and a non-alpha male subjects; all these integrins participate in vital biological processes such as maintenance of tissue integrity, embryonic development, cell

  10. Isolated asymptomatic masseter muscle metastasis as first sign of metastatic disease in a patient with known melanoma

    DEFF Research Database (Denmark)

    Gjorup, Caroline Asirvatham; Hendel, Helle Westergren; Svane, Inge Marie

    2016-01-01

    A 65-year-old woman diagnosed with a nodular melanoma on the right shoulder had a PET/CT scan 13 months later demonstrating a FDG-avid mass in the left masseter muscle, which was asymptomatic and not clinically evident. Pathologic analysis confirmed metastasis of melanoma. Further subcutaneous......, intramuscular and bone metastases developed and the patient was treated with surgery and immunotherapy. The patient is in complete-remission with no evident metastases seen on PET/CT 2.5 years after treatment with adoptive cell therapy using tumor-infiltrating lymphocytes (TIL therapy). Asymptomatic skeletal...

  11. Involvement of trigeminal transition zone and laminated subnucleus caudalis in masseter muscle hypersensitivity associated with tooth inflammation.

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    Kohei Shimizu

    Full Text Available A rat model of pulpitis/periapical periodontitis was used to study mechanisms underlying extraterritorial enhancement of masseter response associated with tooth inflammation. Periapical bone loss gradually increased and peaked at 6 weeks after complete Freund's adjuvant (CFA application to the upper molar tooth pulp (M1. On day 3, the number of Fos-immunoreactive (IR cells was significantly larger in M1 CFA rats compared with M1 vehicle (veh rats in the trigeminal subnucleus interpolaris/caudalis transition zone (Vi/Vc. The number of Fos-IR cells was significantly larger in M1 CFA and masseter (Mass capsaicin applied (M1 CFA/Mass cap rats compared with M1 veh/Mass veh rats in the contralateral Vc and Vi/Vc. The number of phosphorylated extracellular signal-regulated kinase (pERK-IR cells was significantly larger in M1 CFA/Mass cap and M1 veh/Mass cap rats compared to Mass-vehicle applied rats with M1 vehicle or CFA in the Vi/Vc. Pulpal CFA application caused significant increase in the number of Fos-IR cells in the Vi/Vc but not Vc on week 6. The number of pERK-IR cells was significantly lager in the rats with capsaicin application to the Mass compared to Mass-vehicle treated rats after pulpal CFA- or vehicle-application. However, capsaicin application to the Mass did not further affect the number of Fos-IR cells in the Vi/Vc in pulpal CFA-applied rats. The digastric electromyographic (d-EMG activity after Mass-capsaicin application was significantly increased on day 3 and lasted longer at 6 weeks after pulpal CFA application, and these increase and duration were significantly attenuated by i.t. PD98059, a MEK1 inhibitor. These findings suggest that Vi/Vc and Vc neuronal excitation is involved in the facilitation of extraterritorial hyperalgesia for Mass primed with periapical periodontitis or acute pulpal-inflammation. Furthermore, phosphorylation of ERK in the Vi/Vc and Vc play pivotal roles in masseter hyperalgesia after pulpitis or

  12. The Electrical Activity of the Temporal and Masseter Muscles in Patients with TMD and Unilateral Posterior Crossbite

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    Krzysztof Woźniak

    2015-01-01

    Full Text Available The aim of this study was to assess the influence of unilateral posterior crossbite on the electrical activity of the temporal and masseter muscles in patients with subjective symptoms of temporomandibular dysfunctions (TMD. The sample consisted of 50 patients (22 female and 28 male aged 18.4 to 26.3 years (mean 20.84, SD 1.14 with subjective symptoms of TMD and unilateral posterior crossbite malocclusion and 100 patients without subjective symptoms of TMD and malocclusion (54 female and 46 male aged between 18.4 and 28.7 years (mean 21.42, SD 1.06. The anamnestic interviews were conducted according to a three-point anamnestic index of temporomandibular dysfunction (Ai. Electromyographical (EMG recordings were performed using a DAB-Bluetooth Instrument (Zebris Medical GmbH, Germany. Recordings were carried out in the mandibular rest position and during maximum voluntary contraction (MVC. Analysis of the results of the EMG recordings confirmed the influence of unilateral posterior crossbite on variations in spontaneous muscle activity in the mandibular rest position and maximum voluntary contraction. In addition, there was a significant increase in the Asymmetry Index (As and Torque Coefficient (Tc, responsible for a laterodeviating effect on the mandible caused by unbalanced right and left masseter and temporal muscles.

  13. Development of an Eletromiograph and Load Cell for the Silent Period Generation and Measurement in Myoelectric Signals of the Masseter and Temporal Muscles

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    Alexandre BALBINOT

    2011-05-01

    Full Text Available This paper presents the development of an experimental system for the Silent Period (SP generation and characterization in the myoelectric signals of the masseter and temporal muscles derived from an impact on the jaw during maximal voluntary contraction. A load cell to monitor the mechanical stimulus intensity responsible for the SP appearance was developed. This load cell was adapted to the mechanic shooter to generate impacts on the jaw, and strain-gages sensors were used for acquiring signals from such impacts. The system consists of a computer, an analog-digital converter, an electromyograph of up to eight channels, a signal conditioner, and a ring-type load cell adapted to a mechanical impact generator called shooter in this work. Surface electrodes were placed on the right masseter, left masseter, right anterior temporal, and left anterior temporal. Individuals were asked to perform the voluntary muscles contraction. The shooter was positioned at a fixed distance of 5 cm from the individual’s jaw and fired to generate the stimulus. The output signal of the load cell was obtained simultaneously with the EMG signals of the masseter and temporal muscles. Incoming data from EMG and load cell were stored in a computer for further processing. This system was tested in three voluntary individuals and the results demonstrated that the system is suitable for this application, so it was able to generate, acquire, and measure the SP of the masseter and temporal myoelectric signals.

  14. Pain and intramuscular release of algesic substances in the masseter muscle after experimental tooth-clenching exercises in healthy subjects.

    Science.gov (United States)

    Dawson, Andreas; Ghafouri, Bijar; Gerdle, Björn; List, Thomas; Svensson, Peter; Ernberg, Malin

    2013-01-01

    To investigate whether experimental tooth clenching leads to a release of algesic substances in the masseter muscle. Thirty healthy subjects (16 females, 14 males) participated. During two sessions, separated by at least 1 week, intramuscular microdialysis was performed to collect masseter muscle 5-hydroxytryptamine (5-HT) and glutamate as well as the metabolic markers pyruvate and lactate. Two hours after the start of microdialysis, participants were randomized to a 20-min repetitive experimental tooth-clenching task (50% of maximal voluntary contraction) or a control session (no clenching). Pain and fatigue were measured throughout. The Friedman and Wilcoxon tests were used for statistical analyses. No alterations were observed in the concentrations of 5-HT, glutamate, pyruvate, and lactate over time in the clenching or control session, or between sessions at various time points. Pain (P pain and fatigue developed with this experimental tooth-clenching model, but they were not associated with an altered release of 5-HT, glutamate, lactate, or pyruvate. More research is required to elucidate the peripheral release of algesic substances in response to tooth clenching.

  15. [Comparison of postmortal changes in the ultrastructure of the masseter muscle and the longissimus dorsi muscle in pigs with PSE-meat].

    Science.gov (United States)

    Bergmann, V

    1975-01-01

    Samples of the two muscles were taken from 8 Landrace fattened pigs, affected with pale, soft exudative meat, during stunning and 15, 30, 45 and 60 minutes after death; also 2, 3, 6, 12, 24 and 48 hours after slaughter, with storage at 20 degrees C for the first six hours and 2-5 degrees C subsequently. Considerable changes were found during the first hour after death, or even in samples taken during stunning, in longissimus dorsi samples. These consisted of destruction of mitochondria and sarcoplasmic reticulum, breakdown of cell membranes, liberation of clumps of fibre protein, disappearance of glycogen, rigor and destruction of capillaries. Such changes would account for the features of pale, soft exudative meat such as water loss, brief rigor, pale colour, deficiency of energy-rich phosphates. By contrast, in the masseter muscles of the same animal these changes did not occur until later, or were in port absent. In both muscle the breakdown of fibres took place by destruction of the "I" bands and the "Z" strips, and this process also commenced in longissimus dorsi before masseter.

  16. Relationship between Occlusal Force Distribution and the Activity of Masseter and Anterior Temporalis Muscles in Asymptomatic Young Adults

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    Aneta Wieczorek

    2013-01-01

    Full Text Available Healthy subjects have a prevalent side on which they display higher-muscle activity during clenching. The relationship between symmetry of masseter muscle (MM and anterior temporalis (TA muscle activities and occlusion has been evaluated on the basis of physiological parameters. The aim of the present study was to investigate whether the symmetry of surface EMG (sEMG activity in asymptomatic young adults is related to symmetry of occlusal contacts. Material. The study population consisted of seventy-two 18-year-old subjects with no temporomandibular disorder (TMD symptoms. Method. All the participants underwent an sEMG recording with an 8-channel electromyograph (BioEMG III. A T-Scan III evolution 7.01 device was used to analyze the occlusal contact points. Results. The correlation between the activity of right (R and left (L TA and the percentage of occlusal contacts was assessed, but no significant differences were found between the RMM and LMM muscles. The differences in the medium values of sEMG between males and females were not statistically significant. Equilibrated muscular activity between RTA and LTA occurred when occlusal contacts reached the percentage of 65% on the left side. Conclusion. The symmetry of sEMG activity in asymptomatic young adults is not related to symmetry of occlusal contacts.

  17. Cysticercosis of masseter

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    B Dilip Kumar

    2011-01-01

    Full Text Available Cysticercosis is a parasitic infestation caused by the larval stage of Taenia solium, a cestodic paratise. It is a common disease in developing countries where it is also endemic. The most commonly infested body organs include subcutaneous tissues, brain and skeletal muscles. It is interesting to note that oral lesion of cysticercosis is a rare event. Here we report an isolated lesion of cysticercosis in the masseter muscle.

  18. Role of cyclic AMP sensor Epac1 in masseter muscle hypertrophy and myosin heavy chain transition induced by β2-adrenoceptor stimulation.

    Science.gov (United States)

    Ohnuki, Yoshiki; Umeki, Daisuke; Mototani, Yasumasa; Jin, Huiling; Cai, Wenqian; Shiozawa, Kouichi; Suita, Kenji; Saeki, Yasutake; Fujita, Takayuki; Ishikawa, Yoshihiro; Okumura, Satoshi

    2014-12-15

    The predominant isoform of β-adrenoceptor (β-AR) in skeletal muscle is β2-AR and that in the cardiac muscle is β1-AR. We have reported that Epac1 (exchange protein directly activated by cAMP 1), a new protein kinase A-independent cAMP sensor, does not affect cardiac hypertrophy in response to pressure overload or chronic isoproterenol (isoprenaline) infusion. However, the role of Epac1 in skeletal muscle hypertrophy remains poorly understood. We thus examined the effect of disruption of Epac1, the major Epac isoform in skeletal muscle, on masseter muscle hypertrophy induced by chronic β2-AR stimulation with clenbuterol (CB) in Epac1-null mice (Epac1KO). The masseter muscle weight/tibial length ratio was similar in wild-type (WT) and Epac1KO at baseline and was significantly increased in WT after CB infusion, but this increase was suppressed in Epac1KO. CB treatment significantly increased the proportion of myosin heavy chain (MHC) IIb at the expense of that of MHC IId/x in both WT and Epac1KO, indicating that Epac1 did not mediate the CB-induced MHC isoform transition towards the faster isoform. The mechanism of suppression of CB-mediated hypertrophy in Epac1KO is considered to involve decreased activation of Akt signalling. In addition, CB-induced histone deacetylase 4 (HDAC4) phosphorylation on serine 246 mediated by calmodulin kinase II (CaMKII), which plays a role in skeletal muscle hypertrophy, was suppressed in Epac1KO. Our findings suggest that Epac1 plays a role in β2-AR-mediated masseter muscle hypertrophy, probably through activation of both Akt signalling and CaMKII/HDAC4 signalling. © 2014 The Authors. The Journal of Physiology © 2014 The Physiological Society.

  19. The effect of sensory level electrical stimulation of the masseter muscle in early stroke patients with dysphagia: A randomized controlled study.

    Science.gov (United States)

    Umay, Ebru K; Yaylaci, Atilay; Saylam, Guleser; Gundogdu, Ibrahim; Gurcay, Eda; Akcapinar, Dehen; Kirac, Zeynep

    2017-01-01

    Dysphagia is a serious cause of morbidity and mortality in stroke patients. As the first study in literature, we aimed to evaluate the effects of sensory-level electrical stimulation (SES) to bilateral masseter muscles in early stroke patients with dysphagia. This study was conducted at the Physical Medicine and Rehabilitation Clinic of our hospital between 2013 and 2015. Ninety-eight patients with dysphagia within the first month after ischemic stroke were included in this study. Patients were evaluated by bedside screening tests (Bedside Dysphagia Score, Neurological Examination Dysphagia Score, Total Dysphagia Score, and Mann Assessment of Swallowing Ability test) and by flexible fibreoptic endoscopic evaluation of swallowing (FEES) methods. All patients were included in a traditional swallowing therapy. Patients were divided into two groups, namely the "stimulation group" and "sham group." SES was applied to bilateral masseter muscles. Evaluation parameters were compared between the groups before and after therapy. The Friedman test, Wilcoxon Signed Rank test, Mann-Whitney U test, and Fisher exact test were used in this study. There was a significant improvement in dysphagia severity scores evaluated by bedside screening tests and FEES in cognitive and total functionality levels except in motor functional independence level in the stimulation group. In the sham group, there were no significant changes in the evaluation parameters. SES applied to bilateral masseter muscles may provide an effective treatment for both dysphagia and cognitive function in early stroke patients.

  20. Illusion caused by vibration of muscle spindles reveals an involvement of muscle spindle inputs in regulating isometric contraction of masseter muscles

    National Research Council Canada - National Science Library

    Tsukiboshi, Taisuke; Sato, Hajime; Tanaka, Yuto; Saito, Mitsuru; Toyoda, Hiroki; Morimoto, Toshifumi; Türker, Kemal Sitki; Maeda, Yoshinobu; Kang, Youngnam

    2012-01-01

    .... In response to the increasing-ramp load, the root mean square (RMS) of masseter EMG activity almost linearly increased under no vibration, while displaying a steep linear increase followed by a slower increase under vibration...

  1. A comparative study of electromyograms of the masseter, temporalis, and anterior digastric muscles obtained by surface and intramuscular electrodes: raw-EMG.

    Science.gov (United States)

    Koole, P; de Jongh, H J; Boering, G

    1991-07-01

    Electromyographic activity was synchronously recorded by surface and intramuscular electrodes in the same muscle. The activity of the left masseter, left temporalis, and both bellies of the anterior digastric muscle was studied by this double registration technique. In rest position no electromyographic activity could be detected in any of the muscles by both techniques. Both techniques give comparable results in cyclic jaw movements. In isometric contractions, however, differences in the registered activity were observed between the surface electrode on the depressor group muscles and the intramuscularly recorded anterior digastric muscles. Silent periods evoked in the elevator muscles were of slightly longer duration when recorded by intramuscular electrodes than when recorded by surface electrodes. A protruded position of the mandible results in a silent period of longer duration than the position of the mandible in maximal occlusion during clenching for both techniques.

  2. The power features of Masseter muscle activity in tension-type and migraine without aura headache during open-close clench cycles

    Directory of Open Access Journals (Sweden)

    Behrouz Alizadeh Savareh

    2017-07-01

    Full Text Available Introduction Different types of headaches and TMJ click influence the masseter muscle activity. The aim of this study was to assess the trend of energy level of the electromyography (EMG activity of the masseter muscle during open-close clench cycles in migraine without aura (MOA and tension-type headache (TTH with or without TMJ click. Methods Twenty-five women with MOA and twenty four women with TTH participated in the study. They matched with 25 healthy subjects, in terms of class of occlusion and prevalence of temporomandibular joint (TMJ with click. The EMG of both masseter muscles were recorded during open-close clench cycles at a rate of 80 cycles per minute for 15 seconds. The mouth opening was restricted to two centimeters by mandibular motion frame. Signal processing steps have been done on the EMG as: noise removing, smoothing, feature extraction, and statistical analyzing. The six statistical parameters of energy computed were mean, Variance, Skewness, Kurtosis, and first and second half energy over all signal energy. Results A three-way ANOVA indicated that during all the cycles, the mean of energy was more and there was a delay in showing the peak of energy in the masseter of the left side with clicked TMJ in MOA group compared to the two other groups, while this pattern occurred inversely in the side with no-clicked TMJ (P < 0.009. The variation of energy was significantly less in MOA group compared to the two other groups in the no-clicked TMJ (P < 0.003. However, the proportion of the first or second part of signal energy to all energy showed that TTH group had less energy in the first part and more energy in the second part in comparison to the two other groups (P < 0.05. Conclusion The study showed different changes in the energy distribution of masseter muscle activity during cycles in MOA and TTH. MOA, in contrast to TTH, had lateralization effect on EMG and interacted with TMJ click.

  3. Effects of gadolinium chloride on basal flow and compression-induced rapid hyperemia in the rabbit masseter muscle.

    Science.gov (United States)

    Turturici, M; Roatta, S

    2014-06-01

    Aim of the present study is to investigate the role of mechano-sensitive channels on basal muscle blood flow and on the compression-induced rapid hyperaemia. To this aim, the mechano-sensitive channel blocker Gadolinium (Gd(3+)) is employed, which already proved to reduce the myogenic response in isolated vessels. Muscle blood flow (MaBF) was recorded from the masseteric artery in 8 urethane-anesthetized rabbits. Rapid hyperemic responses were evoked by 1-s lasting compressions of the masseter muscle (MC) delivered before and after close arterial infusion of Gd(3+) in the masseteric artery. Three infusions were performed at 1-h interval, producing estimated plasma concentration (EPC) of 0.045, 0.45 and 4.5 mM, in the masseteric artery. The amplitude of the hyperaemic response to MC, equal to 195±77% of basal flow in control condition, was reduced by 9.5±19.4% (p=0.18) and 45±28% (p<0.01) while basal MaBf increased by 10±3% (p=0.90) and by 68±30% (p<0.01) at EPC of 0.045 and 0.45 mM, respectively. At EPC of 4.5 mM a strong reduction in both MaBF (by 54±13%, p<0.01) and MC response (75±12%, p<0.01) was instead observed. These effects did not depend on time from infusion. At all doses employed Gd(3+) never affected arterial blood pressure, heart rate and contralateral MaBF. While the effects observed at the highest EPC likely result from blood vessel occlusion due to Gd(3+) precipitation, the effects observed at lower concentrations demonstrate that Gd(3+) affects musculo-vascular function by decreasing both resting vascular tone and responsiveness to mechanical stimuli. The results are compatible with a Gd(3+)-induced blockade of vascular mechano-sensitive channels.

  4. [Quantitative topographic characterization of the myoelectric activity distribution of the masseter muscle: mapping of spectral EMG parameters].

    Science.gov (United States)

    Scholle, H C; Schumann, N P; Anders, C; Mey, E

    1992-09-01

    A new method for quantitative characterization of myoelectrical masseter activity distribution by mapping of spectral EMG-parameters is described. The surface electromyograms of M. masseter were monopolarly recorded (16 channels). On the basis of registered EMG intervals (512 ms) the spectral EMG power of several frequency bands was calculated (Fast Fourier Transformation). The spectral EMG parameters between the 16 electrode positions were estimated by linear interpolation (4-nearest neighbours algorithm). Afterwards the spectral EMG parameters were fitted in a grey-tone or colour scale with 10 intervals. The so obtained EMG activity maps ("EMG-Maps") permit a quantitative-topographic characterization of myoelectrical masseter activity during different functional load procedures. The frequency range which is to consider in masseter surface-EMG investigations encloses frequencies between 15 and 500 Hz. The topography of EMG activation pattern of M. masseter is only described in a comprehensive manner when the electrode array consists of 16 electrodes and more. During defined motor tasks like clenching with controlled forces the reproducibility of EMG-Maps which respect to the topography of EMG activity pattern is very high. The absolute values of spectral EMG power as well as power changes of selected band ranges during clenching correlate to the extent of chewing forces.

  5. Cysticercosis of the masseter

    Directory of Open Access Journals (Sweden)

    Prabhath Ramakrishnan

    2012-01-01

    Full Text Available Cysticercosis of the oral cavity is a very rare soft tissue lesion and very few cases have been reported worldwide. Here we report a case of a cysticercous cellulosae within the masseter muscle which was diagnosed with the help of high resolution ultrasonography (USG and ultrasound guided fine needle aspiration cytology (FNAC and managed conservatively using oral antiparasitic medication. Cysticercosis is not commonly considered in the diagnosis of swellings of the head and neck and this is the reason why they are of utmost interest to the practitioner and have to be studied.

  6. Effect of intramuscular injection of botulinum toxin type A and triamcinolone to the masseter muscle on the development of mandible: an experimental study%咬肌内注射A型肉毒毒素和曲安奈德对大鼠下颌骨发育影响的实验研究

    Institute of Scientific and Technical Information of China (English)

    黄进军; 王晋煌; 柳大烈; 陈伯华; 陈兵

    2011-01-01

    Objective To evaluate the effect of intramuscular injection of botulinum toxin type A and triamcinolone to the masseter muscle on the development of mandible. Methods Thirty 28-days-old Wistar rats were divided into four groups: botulinum toxin type A group ( B group, 8 rats) , triamcinolone group (T group,8 rats) , botulinum toxin type A and triamcinolone group ( BT group, 8 rats) . control group ( C group, 6 rats) .The right side of masseter muscle was injected with the drugs corresponding to its group and the left side of masseter muscle was injected with saline. The control group was only anaesthetised. CT scan and 3D reconstruction were taken when the rats were 75 days old. Seven cephalometric points were digitized and selected 7 linear distances were measured. The rats were killed with an overdose of 10% chloral hydrate after CT scan. Masseter muscles of each side were obtained and weighted immediately. Results Significant atrophy of masseter muscles were observed in the B group and BT group. Mandibular length Ⅲ ( Go-Iia) . mandibular height Ⅱ ( Cor-GoT)on the right side was less than that on the left side in B group. Mandibular height Ⅱ on the right side was less than that on the left side in BT group. The variances of mandibular height Ⅱ and mandibular height Ⅲ ( ConGoT) on the right side between 4 groups were significant. Conclusion Changes on mandibular height after intramuscular injection of botulinum toxin type A to the masseter muscle were seen. But alterations of mandibular length and bigonial width were not found. Cephalometric changes were not obvious on the triamcinolone group.%目的 探讨咬肌内注射A型肉毒毒素和曲安奈德对大鼠下颌骨发育的影响.方法 取28日龄雄性Wistar大鼠为实验对象,随机分为4组:A型肉毒毒素组(B组,n=8)、曲安奈德组(T组,n=8)、A型肉毒毒素+曲安奈德组(BT组,n=8)、对照组(C组,n=6),每组大鼠取右侧咬肌并向肌内注射相应的药物,左侧注射等

  7. Management of trismus by masseter myotomy

    Directory of Open Access Journals (Sweden)

    Sonal Bhavesh Shah

    2014-01-01

    Full Text Available Mild trismus after parotid gland surgery may be related to inflammation and fibrosis of the masseter muscle. We present a case of long standing trismus due to masseter muscle spasm caused by a recurrent pleomorphic adenoma. As the patient did not agree for removal of the pleomaorphic adenoma, owing to the risk of injuring the facial nerve, a masseter myotomy with inter-positioning of temporalis fascia was planned for symptomatic relief. Mouth opening showed significant improvement even 1 year post-operatively.

  8. Evidence that the contraction-induced rapid hyperemia in rabbit masseter muscle is based on a mechanosensitive mechanism, not shared by cutaneous vascular beds.

    Science.gov (United States)

    Turturici, Marco; Mohammed, Mazher; Roatta, Silvestro

    2012-08-15

    Several mechanisms have been hypothesized to contribute to the rapid hyperemia at the onset of exercise. The aim of the present study was to investigate the role played by the mechanosensitivity of the vascular network. In 12 anesthetized rabbits blood flow was recorded from the exclusively muscular masseteric artery in response to brief spontaneous contractions (BSC) of the masseter muscle, artery occlusion (AO), muscle compression (MC), and muscle stretch (MS). Activation of masseter muscle was monitored by electromyography (EMG). Responses to AO were also recorded from the mostly cutaneous facial and the central ear arteries. Five animals were also tested in the awake condition. The hyperemic response to BSC (peak amplitude of 394 ± 82%; time to peak of 1.8 ± 0.8 s) developed with a latency of 300-400 ms from the beginning of the EMG burst and 200-300 ms from the contraction-induced transient flow reduction. This response was neither different from the response to AO (peak amplitude = 426 ± 158%), MC, and MS (P = 0.23), nor from the BSC response in the awake condition. Compared with the masseteric artery, the response to AO was markedly smaller both in the facial (83 ± 18%,) and in the central ear artery (68 ± 20%) (P < 0.01). In conclusion, the rapid contraction-induced hyperemia can be replicated by a variety of stimuli affecting transmural pressure in muscle blood vessels and is thus compatible with the Bayliss effect. This prominent mechanosensitivity appears to be a characteristic of muscle and not cutaneous vascular beds.

  9. Botulinum toxin in masticatory muscles of the adult rat induces bone loss at the condyle and alveolar regions of the mandible associated with a bone proliferation at a muscle enthesis.

    Science.gov (United States)

    Kün-Darbois, Jean-Daniel; Libouban, Hélène; Chappard, Daniel

    2015-08-01

    In man, botulinum toxin type A (BTX) is injected in masticatory muscles for several indications such as trismus, bruxism, or masseter hypertrophy. Bone changes in the mandible following BTX injections in adult animal have therefore became a subject of interest. The aim of this study was to analyze condylar and alveolar bone changes following BTX unilateral injections in masseter and temporal muscles in adult rats. Mature male rats (n = 15) were randomized into 2 groups: control (CTRL; n = 6) and BTX group (n= 9). Rats of the BTX group received a single injection of BTX into right masseter and temporal muscles. Rats of the CTRL group were similarly injected with saline solution. Rats were sacrificed 4 weeks after injections. Masticatory muscles examination and microcomputed tomography (microCT) were performed. A significant difference of weight was found between the 2 groups at weeks 2, 3 and 4 (p condylar areas in BTX rats. Decrease in bone volume reached -20% for right alveolar bone and -35% for right condylar bone. A hypertrophic bone metaplasia at the digastric muscle enthesis was found on every right hemimandible in the BTX group and none in the CTRL group. BTX injection in masticatory muscles leads to a significant and major mandible bone loss. These alterations can represent a risk factor for fractures in human. The occurrence of a hypertrophic bone metaplasia at the Mus Digastricus enthesis may constitute an etiological factor for tori.

  10. Peripheral mGluR5 antagonist attenuated craniofacial muscle pain and inflammation but not mGluR1 antagonist in lightly anesthetized rats.

    Science.gov (United States)

    Lee, Ho Jeong; Choi, Hyo Soon; Ju, Jin Sook; Bae, Yong Chul; Kim, Sung Kyo; Yoon, Young Wook; Ahn, Dong Kuk

    2006-10-16

    The present study investigated the role of peripheral group I metabotropic glutamate receptors (mGluRs) in MO-induced nociceptive behaviour and inflammation in the masseter muscles of lightly anesthetized rats. Experiments were carried out on male Sprague-Dawley rats weighing 300-400 g. After initial anesthesia with sodium pentobarbital (40 mg/kg, i.p.), one femoral vein was cannulated and connected to an infusion pump for intravenous infusion of sodium pentobarbital. The rate of infusion was adjusted to provide a constant level of anesthesia. Mustard oil (MO, 30 microl) was injected into the mid-region of the left masseter muscle via a 30-gauge needle over 10s. After 30 microl injection of 5, 10, 15, or 20% MO into the masseter muscle, the total number of hindpaw shaking behaviour and extravasated Evans' blue dye concentration in the masseter muscle were significantly higher in the MO-treated group in a dose-dependent manner compared with the vehicle (mineral oil)-treated group. Intramuscular pretreatment with 3 or 5% lidocaine reduced MO-induced hindpaw shaking behaviour and increases in extravasated Evans' blue dye concentration. Intramuscular pretreatment with 5 mM MCPG, non-selective group I/II mGluR antagonist, or MPEP, a selective group I mGluR5 antagonist, produced a significant attenuation of MO-induced hindpaw shaking behaviour and increases in extravasated Evans' blue dye concentration in the masseter muscle while LY367385, a selective group I mGluR1 antagonist, did not affect MO-induced nociceptive behaviour and inflammation in the masseter muscle. These results indicate that peripheral mGluR5 plays important role in mediating MO-induced nociceptive behaviour and inflammation in the craniofacial muscle.

  11. Growth effects of botulinum toxin type A injected unilaterally into the masseter muscle of developing rats%咬肌单侧注射A型肉毒毒素对大鼠下颌骨生长发育的影响

    Institute of Scientific and Technical Information of China (English)

    Chanyoung PARK; Kitae PARK; Jiyeon KIM

    2015-01-01

    Objective:To evaluate the effects of botulinum toxin type A (BTX-A) on mandible skeletal development by inducing muscle hypofunction. Methods:Four-week-old Sprague-Dawley rats (n=60) were divided into three groups:Group 1 animals served as controls and were injected with saline; Group 2 animals were injected unilateral y with BTX-A (the contralateral side was injected with saline);and Group 3 animals were injected bilateral y with BTX-A. In Group 2, the saline-injected side was designated the control side (Group 2-1), whereas the BTX-A-injected side was designated the experimental side (Group 2-2). After four weeks, the animals were sacrificed, dry skulls were prepared, and mandibles were measured. Results: In the unilateral group, the experimental side (Group 2-2) had reduced di-mensions for al mandible measurements compared with the control side (Group 2-1), suggesting a local effect of BTX-A on mandible growth, likely due to muscle reduction. Conclusions:Localized BTX-A injection induced a change in craniofacial growth, and the skeletal effect was unilateral despite both sides of the mandible functioning as one unit.%通过诱导肌肉功能衰退,评估 A 型肉毒毒素(BTX-A)对下颌骨生长发育的影响。

  12. Correlation between the clinical phonoaudiological assessment and electromyographic activity of the masseter muscle Correlação entre a avaliação clínico-fonoaudiológica e a eletromiográfica do músculo masseter

    Directory of Open Access Journals (Sweden)

    Daiana Cristina Biasotto

    2005-12-01

    Full Text Available OBJECTIVE: The objective of this paper was to evaluate the specificity of masseter muscle palpation when compared to its electromyographic activity. MATERIALS AND METHODS: Twenty-one young female adults, aged between 17 and 25, participated in this research. The speech therapy evaluation data were obtained by two speech therapists through masseter muscle palpation during isometric contraction, and the electromyographic exam was achieved by using bipolar superficial electrodes, positioned on the masseter muscle. The volunteers were instructed to chew the Parafilm M® material bilaterally and simultaneously. The capture of the electromiographic signals occurred during masseter muscle isometric contractions. The electrical activity study of the masticatory muscle was analyzed through the Root Mean Square value during its isotonic contraction. STATISTICAL ANALYSIS: All data were then submitted to Kappa statistical analysis. RESULTS: The results of this study have shown a low correlation between palpation and electromyography (25%, as well as between evaluators (40%. CONCLUSION: According to the findings of the present study, it could be observed that the correlation between masseter muscle palpation and its electromyographic activity was very low, which allows to conclude that muscular palpation cannot effectively replace the eletromyographical exam, but complement it instead.OBJETIVO: Este trabalho teve como objetivo avaliar a correlação entre os resultados obtidos na palpação e os dados obtidos no exame eletromiográfico do músculo masseter. MATERIAL E MÉTODO: Participaram deste estudo 21 adultos jovens do sexo feminino, idades entre 17-25 anos. Os dados da avaliação fonoaudiológica foram obtidos por meio da palpação do músculo masseter durante a contração isométrica por dois fonoaudiólogos e os dados eletromiográficos foram captados com a utilização de eletrodos de superfície bipolares posicionados no músculo masseter durante

  13. Pressure pain thresholds assessed over temporalis, masseter, and frontalis muscles in healthy individuals, patients with tension-type headache, and those with migraine--a systematic review.

    Science.gov (United States)

    Andersen, Sanne; Petersen, Marie Weinreich; Svendsen, Anette Sand; Gazerani, Parisa

    2015-08-01

    A systematic review was conducted to identify and summarize the available scientific literature addressing pressure pain threshold (PPT) values over the temporalis, masseter, and frontalis muscles in healthy humans, patients with tension-type headache (TTH), and those with migraine both in males and females. Six relevant medical databases for the literature search were included: PubMed, Web of Science, Cochrane, CINAHL, BioMed Central, and Embase. The search strategy was performed applying 15 keywords (eg, pressure pain threshold, temporalis muscle, tension type headache, pressure algometer) and their combinations. A total of 156 articles were identified, and 40 relevant articles were included. The main outcomes of the systematic review were extracted, and it was demonstrated that the PPT values in general were lower in patients compared with healthy subjects, and this was especially noted for temporalis in both females (migraine: 231.2 ± 38.3 kPa craniofacial muscles of healthy subjects, patients with TTH, and those with migraine to provide the PPT value ranges. Based on these findings, a set of guidelines was established to assist future studies including PPT assessments over craniofacial muscles.

  14. A intervenção fonoaudiológica no pós-operatório da hipertrofia benigna do músculo masseter The miofunctional oral intervention in the surgery treatment for the masseter muscle hipertrophy

    OpenAIRE

    Laura Davison Mangilli; Christiane Siman Rodrigues; Alcione Ramos Campiotto

    2006-01-01

    OBJETIVO: descrever a abordagem fonoaudiológica no pós-operatório de pacientes que realizaram correção cirúrgica da hipertrofia do músculo masseter. METODOLOGIA: foram coletados dados referentes à avaliação e ao tratamento fonoaudiológico de 4 prontuários de sujeitos de ambos os gêneros, com faixa etária entre 16 e 24 anos, com hipertrofia benigna do músculo masseter, tratados cirurgicamente. RESULTADOS: as principais queixas pós-cirúrgicas estiveram relacionadas à limitação da abertura da bo...

  15. The relationship between masseter force and masseter electromyogram during mastication in the monkey Macaca fascicularis.

    Science.gov (United States)

    Hylander, W L; Johnson, K R

    1989-01-01

    In five adult monkeys, electromyograms (EMGs) were recorded from bipolar surface electrodes positioned over the superficial masseter and from bipolar fine-wire electrodes within both the superficial and deep masseter. Relative masseter force was estimated by measuring surface bone strain from the lateral aspect of the zygomatic arch using rosette strain gauges. Multiple step-wise regression procedures demonstrated that peak values of the averaged masseter EMG could often explain a considerable amount of the variation of peak relative masseter force during mastication, i.e. r2 values ranged from 0.23 to 0.96 for the various single-electrode models and R2 values ranged from 0.78 to 0.96 for the various multiple-electrode models. The r2 values for relative masseter force and EMG data from the surface electrodes ranged from 0.69 to 0.96, and, on average, EMG data from surface electrodes provided somewhat more information about overall relative muscle force than data from fine-wire electrodes. The R2 values for a two-electrode model, consisting of data from surface electrodes over the superficial masseter and fine-wire electrodes in the posterior portion of the deep masseter, ranged from 0.78 to 0.95. The latency between the averaged surface EMG and relative muscle force was determined and the data indicated that the surface EMG usually preceded muscle force. This latency tended to decrease gradually throughout the entire power stroke of mastication. At peak values, the surface EMG preceded muscle force by about 22 ms. Towards the end of the power stroke, i.e. the 25% of peak values during unloading, muscle force may actually precede the average EMG.

  16. Myosin proteins identified from masseter muscle using quantitative reverse transcriptase-polymerase chain reaction--a pilot study of the relevance to orthodontics.

    Science.gov (United States)

    Suchak, Archna; Hunt, Nigel P; Shah, Rishma; Sinanan, Andrea C M; Lloyd, Tim; Lewis, Mark P

    2009-04-01

    There is a clearly established relationship between masticatory muscle structure and facial form. Human studies in this area, however, have been limited, especially in consideration of the myosin heavy chain (MyHC) family of contractile proteins. The aim of this pilot study was to assess if differences were detectable between genotype with respect to MyHC isoforms and the vertical facial phenotype in a sample of nine Caucasian female patients, age range 18-49 years, using a novel rapid technique. Masseter muscle biopsies were taken from patients with a range of vertical facial form. The levels of expression of the MyHC isoform genes MYH 1, 2, 3, 6, 7, and 8 were compared with the expression in a female calibrator patient aged 23 years with normal vertical facial form, using quantitative reverse transcriptase-polymerase chain reaction (RT-PCR) analysis. Statistical analysis was undertaken using Pearson correlation coefficient. The results showed that there were distinct differences in gene expression between patients with a wide range of variation although changes in MYH1 were consistent with one cephalometric variable, the maxillo-mandibular angle. The full procedure, from start to finish, can be completed within half a day. Rapid genotyping of patients in this way could reveal important information of relevance to treatment. This technology has potential as a diagnostic and prognostic aid when considering correction of certain malocclusions.

  17. Composition of Muscle Fiber Types in Rat Rotator Cuff Muscles.

    Science.gov (United States)

    Rui, Yongjun; Pan, Feng; Mi, Jingyi

    2016-10-01

    The rat is a suitable model to study human rotator cuff pathology owing to the similarities in morphological anatomy structure. However, few studies have reported the composition muscle fiber types of rotator cuff muscles in the rat. In this study, the myosin heavy chain (MyHC) isoforms were stained by immunofluorescence to show the muscle fiber types composition and distribution in rotator cuff muscles of the rat. It was found that rotator cuff muscles in the rat were of mixed fiber type composition. The majority of rotator cuff fibers labeled positively for MyHCII. Moreover, the rat rotator cuff muscles contained hybrid fibers. So, compared with human rotator cuff muscles composed partly of slow-twitch fibers, the majority of fast-twitch fibers in rat rotator cuff muscles should be considered when the rat model study focus on the pathological process of rotator cuff muscles after injury. Gaining greater insight into muscle fiber types in rotator cuff muscles of the rat may contribute to elucidate the mechanism of pathological change in rotator cuff muscles-related diseases. Anat Rec, 299:1397-1401, 2016. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

  18. Management of Unilateral Masseter Hypertrophy and Hypertrophic Scar—A Case Report

    Directory of Open Access Journals (Sweden)

    Naresh Shetty

    2012-01-01

    Full Text Available Masseter muscle hypertrophy is a rare condition of idiopathic cause. It clinically presents as an enlargement of one or both masseter muscles. Most patients complain of facial asymmetry; however, symptoms such as trismus, protrusion, and bruxism may also occur. Several treatment options reported for masseter hypertrophy are present, which range from simple pharmacotherapy to more invasive surgical reduction. Keloid scar with unilateral masseter hypertrophy is a rarely seen in clinical practice. This paper reports a case of unilateral masseter hypertrophy with keloid scar in the angle of the mandible for which surgical treatment was rendered to the patient by using a single approach.

  19. Avaliação eletromiográfica do músculo masseter em pessoas com paralisia facial periférica de longa duração Masseter muscle electromyographic assessment in subject with long lasting facial palsy

    Directory of Open Access Journals (Sweden)

    Adriana Rahal

    2007-06-01

    Full Text Available OBJETIVO: verificar a atividade elétrica do músculo masseter em pessoas com paralisia facial periférica de longa duração. MÉTODOS: participaram deste estudo seis sujeitos de ambos os sexos, com paralisia facial há pelo menos doze meses, sem queixas mastigatórias e sem disfunção temporomandibular e com pelo menos seis dentes em cada hemiarcada. Todos preencheram um questionário de anamnese e em seguida foram submetidos à eletromiografia de superfície dos masseteres de ambos os lados. As provas eletromiográficas foram: posição habitual com lábios fechados, apertamento dentário, mastigação habitual e unilateral à direita e à esquerda com uva passa. RESULTADOS: em todas as provas eletromiográficas não foram observadas diferenças significantes (p=0,05 entre os lados com e sem paralisia facial. CONCLUSÃO: observou-se com o presente estudo que a força do músculo masseter não sofre influência da paralisia facial de longa duração.PURPOSE: to check the masseter electrical activity in long lasting facial paralysis patients. METHODS: six subjects, with facial paralysis for over a period of twelve months, males and females, took part in this study. Patients should not show any masticatory complaints or have any diagnoses of temporo-mandibular joint dysfunction, having at least six teeth in each half dental ridge. All subjects filled out a questionnaire regarding oral habits and were assessed by surface electromyography of the masseter muscle of both sides. Electromyographic records were taken with lips closed at rest, teeth tightness, besides usual mastication, and unilateral mastication on both sides with raisins. RESULTS: in all electromyographic tests there were no statistically significant differences (p=0.05 between both sides, with and without facial paralysis. CONCLUSION: it was observed that the strength of the masseter muscle is not under the influence of long lasting facial paralysis.

  20. No effect of experimental occlusal interferences on pressure pain thresholds of the masseter and temporalis muscles in healthy women

    NARCIS (Netherlands)

    Michelotti, A; Farella, M; Steenks, MH; Gallo, LM; Palla, S

    It has been suggested that occlusal interferences may lead to pain and tenderness of the masticatory muscles. Tender jaw muscles are more sensitive to pressure pain, as assessed by means of pressure algometry. We tested the effects of occlusal interferences on the pressure pain threshold of the jaw

  1. The role of TRPA1 in muscle pain and mechanical hypersensitivity under inflammatory conditions in rats.

    Science.gov (United States)

    Asgar, J; Zhang, Y; Saloman, J L; Wang, S; Chung, M-K; Ro, J Y

    2015-12-03

    Transient receptor potential cation channel, subfamily A, member 1 (TRPA1) is expressed in muscle afferents and direct activation of these receptors induces acute mechanical hypersensitivity. However, the functional role of TRPA1 under pathological muscle pain conditions and mechanisms by which TRPA1 mediate muscle pain and hyperalgesia are not clearly understood. Two rodent behavioral models validated to assess craniofacial muscle pain conditions were used to study ATP- and N-Methyl-D-aspartate (NMDA)-induced acute mechanical hypersensitivity and complete Freund's adjuvant (CFA)-induced persistent mechanical hypersensitivity. The rat grimace scale (RGS) was utilized to assess inflammation-induced spontaneous muscle pain. Behavioral pharmacology experiments were performed to assess the effects of AP18, a selective TRPA1 antagonist under these conditions. TRPA1 expression levels in trigeminal ganglia (TG) were examined before and after CFA treatment in the rat masseter muscle. Pre-treatment of the muscle with AP18 dose-dependently blocked the development of acute mechanical hypersensitivity induced by NMDA and α,β-methylene adenosine triphosphate (αβmeATP), a specific agonist for NMDA and P2X3 receptor, respectively. CFA-induced mechanical hypersensitivity and spontaneous muscle pain responses were significantly reversed by post-treatment of the muscle with AP18 when CFA effects were most prominent. CFA-induced myositis was accompanied by significant up-regulation of TRPA1 expression in TG. Our findings showed that TRPA1 in muscle afferents plays an important role in the development of acute mechanical hypersensitivity and in the maintenance of persistent muscle pain and hypersensitivity. Our data suggested that TRPA1 may serve as a downstream target of pro-nociceptive ion channels, such as P2X3 and NMDA receptors in masseter afferents, and that increased TRPA1 expression under inflammatory conditions may contribute to the maintenance of persistent muscle pain

  2. Intramuscular administration of morphine reduces mustard-oil-induced craniofacial-muscle pain behavior in lightly anesthetized rats.

    Science.gov (United States)

    Han, Seung R; Lee, Min K; Lim, Koang H; Yang, Gwi Y; Jeon, Hye J; Ju, Jin S; Yoon, Young W; Kim, Sung K; Ahn, Dong K

    2008-04-01

    The present study investigated the role of peripheral opioid receptors in mustard oil-induced nociceptive behavior and inflammation in the masseter muscles of lightly anesthetized rats. Experiments were carried out on male Sprague-Dawley rats weighing between 300 and 400 g. After initial anesthesia with sodium pentobarbital (40 mg/kg, i.p.), one femoral vein was cannulated and connected to an infusion pump for the intravenous infusion of sodium pentobarbital. The rate of infusion was adjusted to provide a constant level of anesthesia. Mustard oil (MO, 30 microl) was injected into the mid-region of the left masseter muscle via a 30-gauge needle. Intramuscularly-administered morphine significantly reduced shaking behavior but not MO-induced inflammation. Intramuscular pretreatment with naloxone, an opioid receptor antagonist, reversed antinociception produced by intramuscularly-administered morphine, while intracisternal administration of naloxone did not affect the antinociception of peripheral morphine. Pretreatment with d-Pen-Cys-Tyr-D-Trp-Orn-Thr-Pen-Thr-NH2 (CTOP), a mu opioid receptor antagonist, but not naltrindole, a delta opioid receptor antagonist, nor norbinaltorphimine (nor-BNI), a kappa opioid receptor antagonist, reversed intramuscularly-administered morphine-induced antinociception. These results indicate that intramuscularly-administered morphine produces antinociception in craniofacial muscle nociception and that this intramuscularly-administered morphine-induced antinociception is mediated by a peripheral mu opioid receptor. Our observations further support the clinical approach of administering opioids in the periphery for the treatment of craniofacial muscle nociception.

  3. Identification of the occurrence and pattern of masseter muscle activities during sleep using EMG and accelerometer systems

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    Sato Sadao

    2009-02-01

    Full Text Available Abstract Background Sleep bruxism has been described as a combination of different orofacial motor activities that include grinding, clenching and tapping, although accurate distribution of the activities still remains to be clarified. Methods We developed a new system for analyzing sleep bruxism to examine the muscle activities and mandibular movement patterns during sleep bruxism. The system consisted of a 2-axis accelerometer, electroencephalography and electromyography. Nineteen healthy volunteers were recruited and screened to evaluate sleep bruxism in the sleep laboratory. Results The new system could easily distinguish the different patterns of bruxism movement of the mandible and the body movement. Results showed that grinding (59.5% was most common, followed by clenching (35.6% based on relative activity to maximum voluntary contraction (%MVC, whereas tapping was only (4.9%. Conclusion It was concluded that the tapping, clenching, and grinding movement of the mandible could be effectively differentiated by the new system and sleep bruxism was predominantly perceived as clenching and grinding, which varied between individuals.

  4. Histological, Histochemical, and Protein Changes after Induced Malocclusion by Occlusion Alteration of Wistar Rats

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    Carolina de Souza Guerra

    2014-01-01

    rats (left side, and the animals were sacrificed after either 14 or 26 days. The masseter muscle was processed for histological analysis, conventional and in situ zymography, and immunohistochemistry. The morphological analysis showed unique and specific characteristics for the experimental group. By conventional zymography no significant values of 72 kDa MMP-2 (P< 0.05 were found in both of the sides of masseter muscle after 14 and 26 days of unilateral extraction. The in situ zymography showed gelatinolytic activity on all deep masseter muscles, with significant increase on the contralateral side after 14 and 26 days (P< 0.05. The immunohistochemistry demonstrated greater expression of MMP-2 than MMP-9 and MMP-14 in all masseter muscles and there were few differences in the staining of 4 TIMPs. This knowledge about morphology and molecular masticatory muscle remodeling following environmental interventions can be used to develop clinically successful treatments.

  5. Development of a behavioral assessment of craniofacial muscle pain in lightly anesthetized rats.

    Science.gov (United States)

    Ro, Jin Y; Capra, Norman; Masri, Radi

    2003-07-01

    In this study, a new behavioral assessment of craniofacial muscle pain in the lightly anesthetized rat is described. Intramuscular injections with algesic agents in lightly anesthetized rats evoked a characteristic ipsilateral hindpaw shaking behavior for several minutes similar to previously described orofacial pain-induced grooming behavior in awake rats (Neurosci Lett 103 (1989) 349, Pain 62 (1995) 295). Eighty-two male Sprague-Dawley rats were used in a series of experiments to study whether this behavior could serve as a valid measure of craniofacial muscle pain. First, we demonstrated that different algesic chemicals, mustard oil (20%), formalin (3%) or hypertonic saline (5%) injected in the mid-region of the masseter muscle effectively elicited the hindpaw shaking behavior. The behavior was only minimally evoked with vehicle injection. Repeated administrations of hypertonic saline, a short duration non-sensitizing algogen, demonstrated reproducibility of the assay. Second, we showed that the peak and overall magnitude of the shaking behavior evoked by injections with different concentrations of mustard oil (1 and 5%) changed in a concentration dependent manner. Finally, we showed that systemic administration of morphine sulfate (3 and 0.3 mg/kg, i.p.) dose dependently attenuated mustard oil induced hindpaw-shaking behavior. Lidocaine injected locally 5 min prior to mustard oil injection also significantly decreased the hindpaw shaking behavior. Based on these results we concluded that ipsilateral hindpaw shaking in lightly anesthetized rats is a stereotypical behavior evoked by noxious muscle stimulation and can be used as a reliable behavioral measure to assess craniofacial muscle pain.

  6. APPLICATION OF MRI IN THE DIAGNOSTICS OF M. MASSETER

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    Mariana Dimova-Gabrovska

    2017-06-01

    Full Text Available Magnetic resonance imaging (MRI is a non-invasive diagnostic method which can provide detailed images of organs and structures of the human body. The purpose of this review is to explore and introduce the diagnostic capabilities of MRI in imaging m. masseter in conditions of norm and pathology. The material of the review is information of 20 literary sources selected from 530, found by keywordsfromJanuary to April 2017. The information about MRI imaging of the normal anatomy of m. masseter and the most common findings in muscle - muscle hypertrophy, inflammatory changes, vascular malformations, intramuscular hemangioma, cysticercosis and changes after radiotherapy was analyzed. In conclusion, the diagnostic capabilities of MRI of masseter muscle – both in the conditions of norm and pathology were confirmed. The method is considered to be reliable, objective, non-invasive and accurate.

  7. Modelling relative masseter force from surface electromyograms during mastication in non-human primates.

    Science.gov (United States)

    Hylander, W L; Johnson, K R

    1993-03-01

    The purpose was to analyse the relation between masseter electromyograms (EMGs) and relative masseter force during the power stroke of mastication. The electromyographic activity of the masseter was characterized by recording from bipolar surface electrodes placed over the superficial portion of the muscle; relative masseter force was estimated by characterizing surface bone strain along the lateral aspect of the zygomatic arch. The subjects were six adult macaques and one adult baboon. Masseter EMGs were quantified by r.m.s. analysis of the raw digitized EMG. The length of the time interval (the time constant) during which the r.m.s. values were calculated was repeatedly altered so as to determine which time constant was optimal for producing an EMG-derived waveform that best mimicked relative masseter force during the near-isometric phase of muscle contraction. The data indicate that between subjects this time constant varied from 35 to 72 ms, with an overall median of 42 ms and a grand mean of 49 ms. The use of a 42-ms time constant for all of the subjects resulted in an average latency between the masseter EMG waveform and relative masseter force of about 30 ms during the latter portion of the power stroke of mastication. This analysis provides, as a first approximation, an empirical basis for modelling relative jaw-muscle force using surface EMGs recorded during that portion of the power stroke of mastication when the jaw-closing muscles are contracting under near isometric conditions.

  8. Effects of masticatory muscle force on temporomandibular joint disc growth in rats.

    Science.gov (United States)

    Sakurai, Makoto; Yonemitsu, Ikuo; Muramoto, Takeshi; Soma, Kunimichi

    2007-12-01

    Biomechanical factors in masticatory function are related to the development of the mandible and the condyle. Previous studies have reported that reduced masticatory muscle force influences mandibular bone formation and chondroblastic proliferation. We examined the importance of compressive force in temporomandibular joint (TMJ) disc growth by reducing the masticatory load. Thirty 3-week-old male Wistar rats were used in this study. In the experimental group, the masseter muscles were bilaterally resected to evaluate the influence of masticatory muscle force on morphology and composition of TMJ disc during growth. No surgery was performed in the control group. The thickness of the TMJ disc was measured to evaluate the morphological changes. The localization of type I collagen and decorin was performed by immunostaining to examine compositional change. Cell proliferation in the disc was identified by insulin-like growth factor-1 receptor (IGF-1r) immunostaining. The disc thickness at each region in the experimental group was reduced compared to the control group. While in the control group, type I collagen and decorin were identified throughout the disc, it was concentrated on the superior portion of the disc at the anterior and posterior bands in the experimental group. The expression of IGF-1r immunopositive cells in the experimental group was also significantly lower than in the control. We conclude that masticatory muscle force is closely related to TMJ disc morphology and composition during growth.

  9. 牙尖交错位最大紧咬时胸锁乳突肌与咬肌肌电研究%Electromyographic activity of the masseter and sternocleidomastoid muscle during maximal voluntary clenching in intercuspal position

    Institute of Scientific and Technical Information of China (English)

    郭少雄; 李宝勇; 张渊; 刘璐; 邓琪; 王美青

    2015-01-01

    Objective :To investigate the relationship between occlusal force level and the surface electro‐myography(SEMG) activity of sternocleidomastoid muscle (SCM )versus masseter muscle(MM ) during maximal voluntary clenching (MVC) in intercuspal position(ICP) .Methods :T‐Scan III system and BioEMG III system were used to record SEMG activity of the SCM and of the MM simultaneously .Recordings which were obtained from 25 healthy young adult during MVC were analyzed in different occlusal force levels .Normalized SEMG value was ratio of SEMG values of different occlusal force levels to MVC .Results :There was no difference between bite force , SEMG value of left side and right side in ICP‐MVC .Ratios of sternocleidomastoid(SCM ) to masseter muscle activity range from (9 .13 ± 4 .77)% to(10 .23 ± 6 .47)% .In normalized SEMG value of the MM and SCM ,which increased before 75% ‐MVC ,and decreased after 75% ‐ICP(P< 0 .05) .Conclusion :The results confirmed that a lower SEMG activity of SCM is similar to MM when the highest level of bite force achieved during MVC in ICP .%目的:以咬肌(Masseter muscle ,MM )为对照,研究牙尖交错位最大紧咬过程中咬合力和胸锁乳突肌(Sternocleidomastoid muscle ,SCM )肌电之间的关系。方法:采用 T‐scanIII 咬合记录仪和 BioEMG III 肌电图仪,同步记录25名健康受试者 SCM 和 MM 的肌电值,分析不同咬合力水平下肌电值与自主最大紧咬(Maximal voluntary clenching ,MVC)时肌电值的比值的变化。结果:M VC 时,咬合力、SCM 及 MM 肌电值双侧之间无明显差异,SCM 肌电幅值约为 MM 的(9.13±4.77)%~(10.23±6.47)%,SCM 及 MM 的肌电比值在达到最大咬合力的75%之前均呈逐渐增高趋势,但从该水平至 MVC 时均显著下降(P< 0.05)。结论:在自主最大紧咬过程中 SCM 表现出与 MM 同步的先升高后降低的肌电变化规律。

  10. The imbalance of masticatory muscle activity affects the asymmetric growth of condylar cartilage and subchondral bone in rats.

    Science.gov (United States)

    Miyazaki, Mutsumi; Yonemitsu, Ikuo; Takei, Maki; Kure-Hattori, Ikuko; Ono, Takashi

    2016-03-01

    To examine the effects of imbalance of masticatory muscle activity of the rat mandible on the condylar cartilage and subchondral bone during the growth period. Forty 5-week-old male Wistar rats were randomly divided into experimental (n=20) and control (n=20) groups. In the experimental group, the left masseter muscles were resected. The rats were sacrificed at 7 or 9 weeks of age in both groups. Microcomputed tomography was used to determine the three-dimensional morphology and cancellous bone structure. For histological and histochemical examination, 5-μm-thick serial frontal sections of the condyle were stained with toluidine blue and immunostained with asporin and TGF-β1 to evaluate the promotion and inhibition of chondrogenesis. In the experimental group, microcomputed tomography analysis showed asymmetric growth; the resected side condyles showed degenerative changes. Histological analysis showed that the total cartilage in the central region of the resected side was significantly thinner than in the non-resected side in the experimental group, as well as in the control group. Compared with the control group, the expression of asporin was significantly higher in the resected side, and significantly lower in the non-resected side. In contrast, the expression of TGF-β1-immunopositive cells in the non-resected side was significantly higher than in the resected side and the control group. These findings imply that lateral imbalance of masseter muscle activity lead to inhibition of chondrogenesis and induce asymmetric formation of the condyle during the growth period. Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.

  11. Uso de toxina botulínica para tratamiento de la hipertrofía del músculo masetero Use of botulinum toxin for treatment of hypetrophy of the masseter muscle

    Directory of Open Access Journals (Sweden)

    F. González Magaña

    2012-09-01

    Full Text Available Definimos la hipertrofia del músculo masetero como el crecimiento excesivo de la masa muscular de dicho músculo, de presentación subclínica y de etiología multifactorial. Presenta una incidencia entre los 20 a 40 años sin predilección de sexo. Desde que en 1880 Legg la describiera por primera vez, se han intentado múltiples tratamientos, desde los médicos hasta los quirúrgicos, siendo el tratamiento con toxina botulínica el de mayor aceptación en la actualidad. El objetivo del presente artículo es realizar una revisión bibliográfica y proveer una herramienta para el médico que se enfrente a la hipertrofia del músculo masetero, además de presentar un caso clínico unilateral y la técnica empleada para su tratamiento. Como método diagnóstico en el paciente empleamos TAC de cráneo y macizo facial con cortes finos a 1 mm, así como de la región maseterina y aplicamos toxina botulínica de acuerdo a la zona de seguridad propuesta por Nam-Ho Kim y en base a los puntos anatómicos que indica el mismo protocolo, a dosis de 50 U en intervalos de 3 meses. Empleamos también TAC postoperatorio como medio de evaluación del resultado. Los tratamientos médicos con toxina botulínica son variables en sus dosis, aplicaciones y técnicas, así como en los diferentes productos disponibles en el mercado. En nuestro caso, el resultado fue clínicamente satisfactorio, cubriendo en su totalidad las expectativas del paciente. Proponemos que la protocolización del paciente, las dosis adecuadas, el tiempo entre aplicaciones y los sitios anatómicos correctos de inyección, llevan a la corrección de la hipertrofia del músculo masetero.Masseter muscle hypertrophy is an overgrowth of muscle mass with subclinical presentation and multifactorial etiology, with an incidence between 20 to 40 years and without sex predilection. In 1880 Legg describes this pathology for the first time and since then have been reported and attempted to formally

  12. Cardiac Muscle Studies with Rat Ventricular Strips

    Science.gov (United States)

    Whitten, Bert K.; Faleschini, Richard J.

    1977-01-01

    Details undergraduate physiology laboratory experiments that demonstrate mechanical properties of cardiac muscle, using strips from the ventricle of a rat heart. Includes procedures for obtaining length-tension curves, demonstrating the role of calcium in excitation-contraction coupling, and showing effects of several cardiovascular drugs…

  13. Muscle bioenergetics in obese Zucker rats.

    Science.gov (United States)

    Klein, M; Kaminsky, P; Walker, P M; Straczek, J; Barbe, F; Duc, M; Burlet, C

    1994-03-01

    The purpose of this study was to investigate the energetic metabolism in obese Zucker rats, using phosphorus nuclear magnetic resonance spectroscopy at rest and during a 2-Hz muscle stimulation and subsequent recovery. Animals were anesthetized with ketamine (150 mg/kg ip). Fed obese rats and 2-day-fasted obese rats were compared with their normally fed and 2-day-fasted lean litter mates. No differences were found between the two groups for ATP, total creatine, phosphocreatine (PCr), and intracellular pH. Starvation in lean rats resulted in a significant fall in inorganic phosphate (Pi), increased resting ADP level, and decreased PCr and ADP recovery after stimulation. The obese rats exhibited a decreased PCr/Pi and increased ADP at rest and a decreased PCr resynthesis and ADP metabolization rate after stimulation. Muscle stimulation in fasted obese rats induced higher PCr depletion and more pronounced acidosis. These results suggest an in vivo mitochondrial metabolism dysfunction in fasted lean as well as in fed and fasted obese rats.

  14. IGF and myostatin pathways are respectively induced during the earlier and the later stages of skeletal muscle hypertrophy induced by clenbuterol, a β₂-adrenergic agonist.

    Science.gov (United States)

    Abo, Tokuhisa; Iida, Ryo-Hei; Kaneko, Syuhei; Suga, Takeo; Yamada, Hiroyuki; Hamada, Yoshiki; Yamane, Akira

    2012-12-01

    Clenbuterol, a β₂-adrenergic agonist, increases the hypertrophy of skeletal muscle. Insulin-like growth factor (IGF) is reported to work as a potent positive regulator in the clenbuterol-induced hypertrophy of skeletal muscles. However, the precise regulatory mechanism for the hypertrophy of skeletal muscle induced by clenbuterol is unknown. Myostatin, a member of the TGFβ super family, is a negative regulator of muscle growth. The aim of the present study is to elucidate the function of myostatin and IGF in the hypertrophy of rat masseter muscle induced by clenbuterol. To investigate the function of myostatin and IGF in regulatory mechanism for the clenbuterol-induced hypertrophy of skeletal muscles, we analysed the expression of myostatin and phosphorylation levels of myostatin and IGF signaling components in the masseter muscle of rat to which clenbuterol was orally administered for 21 days. Hypertrophy of the rat masseter muscle was induced between 3 and 14 days of oral administration of clenbuterol and was terminated at 21 days. The expression of myostatin and the phosphorylation of smad2/3 were elevated at 21 days. The phosphorylation of IGF receptor 1 (IGFR1) and akt1 was elevated at 3 and 7 days. These results suggest that myostatin functions as a negative regulator in the later stages in the hypertrophy of rat masseter muscle induced by clenbuterol, whereas IGF works as a positive regulator in the earlier stages. Copyright © 2012 John Wiley & Sons, Ltd.

  15. Segmental fibre type composition of the rat iliopsoas muscle.

    Science.gov (United States)

    Vlahovic, Hrvoje; Bazdaric, Ksenija; Marijancic, Verner; Soic-Vranic, Tamara; Malnar, Daniela; Arbanas, Juraj

    2017-01-18

    The iliopsoas of the rat is composed of two muscles - the psoas major muscle and the iliacus muscle. The psoas major muscle arises from all the lumbar vertebrae and the iliacus muscle from the fifth and sixth lumbar vertebrae and ilium. Their common insertion point is the lesser trochanter of the femur, and their common action is the lateral rotation of the femur and flexion of the hip joint. Unlike humans, the rat is a quadruped and only occasionally rises up on its hind legs. Therefore, it is expected that the fibre type composition of the rat iliopsoas muscle will be different than that of humans. The iliopsoas muscle of the rat is generally considered to be a fast muscle. However, previous studies of the fibre type composition of the rat psoas muscle showed different results. Moreover, very little is known about the composition of the rat iliacus muscle. The aim of our study was to examine the fibre type composition of the rat iliopsoas muscle in order to better understand the complex function of the listed muscle. The psoas major muscle was examined segmentally at four different levels of its origin. Type I, IIA, IIB and IIX muscle fibres were typed using monoclonal antibodies for myosin heavy chain identification. The percentage of muscle fibre types and muscle fibre cross-sectional areas were calculated. In our study we showed that in the rat iliopsoas muscle both the iliacus and the psoas major muscles had a predominance of fast muscle fibre types, with the highest percentage of the fastest IIB muscle fibres. Also, the IIB muscle fibres showed the largest cross-sectional area (CSA) in both muscles. As well, the psoas major muscle showed segmental differences of fibre type composition. Our results showed changes in percentages, as well as the CSAs of muscle fibre types in cranio-caudal direction. The most significant changes were visible in type IIB muscle fibres, where there was a decrease of percentages and the CSAs from the cranial towards the caudal part

  16. Testosterone and muscle hypertrophy in female rats

    Science.gov (United States)

    Kuhn, F. E.; Max, S. R.

    1985-01-01

    The effects of chronic treatment with testosterone propionate (TP) on compensatory muscle hypertropy in female rats are examined. The 48 female rats were placed in one of four test groups: (1) no overload (synergist removal), no TP, (2) overload, no TP, (3) no overload + TP, and (4) overload + TP. The technique used to administer the TP is described. The preparation of the plantaris muscle, the analysis of pyruvate oxidation and the determination of malate and lactate dehydrogenases and the noncollogen protein are explained. The results which reveal the effect of overload and TP on body weight, noncollogen protein concentration, lactate and malate dehydrogenase activities, and pyruvate oxidation are presented and discussed. It is concluded that in terms of body weight, protein content, pyruvate, glycolysis, and oxidative metabolisms chronic TP treatments do not change compensatory muscle hypertropy.

  17. Testosterone and muscle hypertrophy in female rats

    Science.gov (United States)

    Kuhn, F. E.; Max, S. R.

    1985-01-01

    The effects of chronic treatment with testosterone propionate (TP) on compensatory muscle hypertropy in female rats are examined. The 48 female rats were placed in one of four test groups: (1) no overload (synergist removal), no TP, (2) overload, no TP, (3) no overload + TP, and (4) overload + TP. The technique used to administer the TP is described. The preparation of the plantaris muscle, the analysis of pyruvate oxidation and the determination of malate and lactate dehydrogenases and the noncollogen protein are explained. The results which reveal the effect of overload and TP on body weight, noncollogen protein concentration, lactate and malate dehydrogenase activities, and pyruvate oxidation are presented and discussed. It is concluded that in terms of body weight, protein content, pyruvate, glycolysis, and oxidative metabolisms chronic TP treatments do not change compensatory muscle hypertropy.

  18. Reconstruction of postoperative soft tissue defect of oral carcinoma using masseter muscle flap: Two cases report and literature review%嚼肌瓣整复口腔癌术后软组织缺损2例及文献回顾

    Institute of Scientific and Technical Information of China (English)

    黄平; 秦旭; 廖琳迪; 黄梅靖; 邵乐南; 陈卫民

    2012-01-01

    目的:总结应用嚼肌瓣修复口腔癌术后软组织缺损的临床效果.方法:收集2例口腔癌病例,利用嚼肌瓣修复术后软组织缺损,并对相关文献进行回顾.结果:口腔癌术后软组织缺损严重影响患者的口腔功能,应用嚼肌瓣以及生物膜整复可获得较为满意的功能及美学效果.结论:应用嚼肌瓣修复口腔癌术后软组织缺损可以获得较为满意的临床效果好.%Objective:To investigare feasibility the postoperative result of using masseter flap as a postoperative soft tissue defect of oral carcinoma reconstruction regional flap. Method: We choosed two cases of oral carcinoma patient, performing oral soft tissue defect reconstruction with masseter muscle flap, then make a briefly literature review. Result: Oral carcinoma is a kind of common head and neck cancer, and its postoperative soft tissue defect have severe impact on the oral function,such as eating, pronunciation, swallowing and so on. The using of split masseter muscle combined with oral biofilm could obtain satisfactory function and aesthetic effect in reconstruction of large area defect caused by the ablation of oral cancer. Conclusion: The masseter muscle can be used as a useful flap to reconstruct targe area oral cancer postoperative defect.

  19. The alterations in adenosine nucleotides and lactic acid levels in striated muscles following death with cervical dislocation or electric shock.

    Science.gov (United States)

    Pençe, Halime Hanim; Pençe, Sadrettin; Kurtul, Naciye; Bakan, Ebubekir; Kök, Ahmet Nezih; Kocoglu, Hasan

    2003-01-01

    In this study, changes in adenosine triphosphate (ATP), adenosine diphosphate (ADP), adenosine monophosphate (AMP) and lactic acid levels in masseter, triceps, and quadriceps muscles obtained from right and left sides of Spraque-Dawley rats following two different types of death were investigated. The samples were taken immediately and 120 minutes after death occurred either by cervical dislocation or electric shock. ATP concentrations in the muscles of masseter, triceps, and quadriceps were lower in samples obtained 120 minutes after death than that of samples obtained immediately after death. ADP, AMP, and lactic acid concentrations in these muscles were higher in samples obtained 120 minutes after death than those obtained immediately after death. A positive linear correlation was determined between ATP and ADP concentrations in quadriceps muscles of the rats killed with cervical dislocation and in masseter muscles of the rats killed with electric shock. When the rats killed with cervical dislocation and with electric shock were compared, ADP, AMP, and lactic acid concentrations were lower in the former than in the latter for both times (immediately and 120 minutes after death occurred). In the case of electric shock, ATP is consumed faster because of immediate contractions during death, resulting in a faster rigor mortis. This finding was confirmed with higher lactic acid levels in muscles of the rats killed with electric shock than the other group. In the cervical dislocation and electric shock group rats, ATP decreased in different levels in the three different muscle types mentioned above, being much decline in masseter in cervical dislocation and in quadriceps in electric shock group. This may be caused by low mass and less glycogen storage of masseter and by near localisation of electrode to quadriceps. One can conclude that the occurrence of rigor mortis is closely related to the mode of death.

  20. Is the long-latency stretch reflex in human masseter transcortical?

    Science.gov (United States)

    Pearce, Sophie L; Miles, Timothy S; Thompson, Philip D; Nordstrom, Michael A

    2003-06-01

    A long-latency stretch reflex (LLSR) has been described in the human masseter muscle, but its pathway remains uncertain. To investigate this, the excitability of corticomotoneuronal (CM) cells projecting to masseter motoneurons during the LLSR was assessed with transcranial magnetic stimulation (TMS). A facilitated response to TMS would be evidence of a LLSR pathway that traverses the motor cortex. Surface electromyogram electrodes were placed over the left or right masseter, and subjects ( n=10) bit on bars with their incisor teeth at 10% of maximal electromyographic activity (EMG). Servo-controlled displacements were imposed on the lower jaw to evoke a short- and long-latency stretch reflex in masseter. TMS intensity was just suprathreshold for a response in contralateral masseter. Trials consisted of: (1) stretch alone, (2) TMS alone, and (3) TMS with a preceding conditioning stretch at varied conditioning-testing (C-T) intervals chosen to combine TMS with the short-latency stretch reflex (3 ms, 5 ms) and the LLSR (23-41 ms). Masseter EMG was rectified and averaged. With TMS alone, mean (+/- SE) MEP area above baseline was 56+/-9%. The area of masseter MEPs above baseline in the C-T trials was calculated from each EMG average following subtraction of the response to stretch alone. Conditioning muscle stretch had no significant effect on masseter MEPs evoked by TMS with any C-T interval (ANOVA; P=0.90). In addition, subjects were unable to modify the SLSR or LLSR by voluntary command. It is concluded that the long-latency stretch reflex in the masseter does not involve the motor cortex and is not influenced by "motor set".

  1. cav-p60 expression in rat muscle tissues. Distribution of caveolar proteins

    DEFF Research Database (Denmark)

    Voldstedlund, M.; Vinten, Jørgen; Tranum-Jensen, Jørgen

    2001-01-01

    Caveolae, Caveolin, muscle, endothel, electron microscopy, immunofluorescence microscopy, rat (Wistar)......Caveolae, Caveolin, muscle, endothel, electron microscopy, immunofluorescence microscopy, rat (Wistar)...

  2. The uremic environment and muscle dysfunction in man and rat

    DEFF Research Database (Denmark)

    Harrison, Adrian Paul; Nielsen, Arne Høj; Eidemak, I.;

    2006-01-01

    patients prior to and after a session of hemodialysis (HD) treatment, alongside in vitro measurements of muscle function in isolated rat muscles incubated in normal or uremic conditions approximating to those found in uremic rats (rat uremic: RU) or uremic humans (human uremic: HU). Results: HD......-twitch). In isolated rat muscles, a uremic environment had no significant effect on slow-twitch soleus during field stimulation, however, in fast-twitch extensor digitorum longus, a significant 23% (RU) and 22% (HU) faster rate of decline in force was measured, compared to controls (p

  3. Muscle fiber types composition and type identified endplate morphology of forepaw intrinsic muscles in the rat.

    Science.gov (United States)

    Pan, Feng; Mi, Jing-Yi; Zhang, Yan; Pan, Xiao-Yun; Rui, Yong-Jun

    2016-06-01

    The failure to accept reinnervation is considered to be one of the reasons for the poor motor functional recovery of intrinsic hand muscles (IHMs) after nerve injury. Rat could be a suitable model to be used in simulating motor function recovery of the IHMs after nerve injury as to the similarities in function and anatomy of the muscles between human and rat. However, few studies have reported the muscle fiber types composition and endplate morphologic characteristics of intrinsic forepaw muscles (IFMs) in the rat. In this study, the myosin heavy chain isoforms and acetylcholine receptors were stained by immunofluorescence to show the muscle fiber types composition and endplates on type-identified fibers of the lumbrical muscles (LMs), interosseus muscles (IMs), abductor digiti minimi (AM) and flexor pollicis brevis (FM) in rat forepaw. The majority of IFMs fibers were labeled positively for fast-switch fiber. However, the IMs were composed of only slow-switch fiber. With the exception of the IMs, the other IFMs had a part of hybrid fibers. Two-dimensional morphological characteristics of endplates on I and IIa muscle fiber had no significant differences among the IFMs. The LMs is the most suitable IFMs of rat to stimulate reinnervation of the IHMs after nerve injury. Gaining greater insight into the muscle fiber types composition and endplate morphology in the IFMs of rat may help understand the pathological and functional changes of IFMs in rat model stimulating reinnervation of IHMs after peripheral nerve injury.

  4. FINE STRUCTURE OF RAT INTRAFUSAL MUSCLE FIBERS

    Science.gov (United States)

    Ovalle, William K.

    1972-01-01

    An ultrastructural study has been undertaken on the equatorial (sensory) region of the rat muscle spindle. Two kinds of intrafusal muscle fibers, a nuclear bag fiber and a nuclear chain fiber, have been identified in this region on the basis of fiber diameter, nuclear disposition, and M-band appearance. The large-diameter nuclear bag fiber contains an aggregation of tightly packed vesicular nuclei, while the small-diameter nuclear chain fiber contains a single row of elongated, well-separated nuclei. Both muscle fibers contain an attenuated peripheral cylinder of myofilaments surrounding a central core of sarcoplasm. Elements of the sarcotubular system, dilatations of the sarcoplasmic reticulum, and the presence of other sarcoplasmic organelles and inclusions are considerably more abundant in the nuclear chain fiber than in the nuclear bag fiber. Leptomeric organelles and membrane-bounded sarcoplasmic granules are present in both intrafusal fiber types and may be situated between the myofibrils or in intimate association with the sarcolemma. The functional significance of some of these structural findings is discussed. PMID:4257999

  5. BRAINSTEM CHOLINERGIC MODULATION OF MUSCLE TONE IN INFANT RATS

    OpenAIRE

    Gall, Andrew J.; Poremba, Amy; Blumberg, Mark S.

    2007-01-01

    In week-old rats, lesions of the dorsolateral pontine tegmentum (DLPT) and nucleus pontis oralis (PnO) have opposing effects on nuchal muscle tone. Specifically, pups with DLPT lesions exhibit prolonged bouts of nuchal muscle atonia (indicative of sleep) and pups with PnO lesions exhibit prolonged bouts of high nuchal muscle tone (indicative of wakefulness). Here we test the hypothesis that nuchal muscle tone is modulated, at least in part, by cholinergically mediated interactions between the...

  6. Contrasting phenotypes of putative proprioceptive and nociceptive trigeminal neurons innervating jaw muscle in rat

    Directory of Open Access Journals (Sweden)

    Connor Mark

    2005-10-01

    Full Text Available Abstract Background Despite the clinical significance of muscle pain, and the extensive investigation of the properties of muscle afferent fibers, there has been little study of the ion channels on sensory neurons that innervate muscle. In this study, we have fluorescently tagged sensory neurons that innervate the masseter muscle, which is unique because cell bodies for its muscle spindles are in a brainstem nucleus (mesencephalic nucleus of the 5th cranial nerve, MeV while all its other sensory afferents are in the trigeminal ganglion (TG. We examine the hypothesis that certain molecules proposed to be used selectively by nociceptors fail to express on muscle spindles afferents but appear on other afferents from the same muscle. Results MeV muscle afferents perfectly fit expectations of cells with a non-nociceptive sensory modality: Opiates failed to inhibit calcium channel currents (ICa in 90% of MeV neurons, although ICa were inhibited by GABAB receptor activation. All MeV afferents had brief (1 msec action potentials driven solely by tetrodotoxin (TTX-sensitive Na channels and no MeV afferent expressed either of three ion channels (TRPV1, P2X3, and ASIC3 thought to be transducers for nociceptive stimuli, although they did express other ATP and acid-sensing channels. Trigeminal masseter afferents were much more diverse. Virtually all of them expressed at least one, and often several, of the three putative nociceptive transducer channels, but the mix varied from cell to cell. Calcium currents in 80% of the neurons were measurably inhibited by μ-opioids, but the extent of inhibition varied greatly. Almost all TG masseter afferents expressed some TTX-insensitive sodium currents, but the amount compared to TTX sensitive sodium current varied, as did the duration of action potentials. Conclusion Most masseter muscle afferents that are not muscle spindle afferents express molecules that are considered characteristic of nociceptors, but these

  7. Skeletal muscle metabolism in hypokinetic rats

    Science.gov (United States)

    Tischler, Marc E.

    1993-01-01

    This grant focused on the mechanisms of metabolic changes associated with unweighting atrophy and reduced growth of hind limb muscles of juvenile rats. Metabolic studies included a number of different areas. Amino acid metabolic studies placed particular emphasis on glutamine and branched-chain amino acid metabolism. These studies were an outgrowth of understanding stress effects and the role of glucocorticoids in these animals. Investigations on protein metabolism were largely concerned with selective loss of myofibrillar proteins and the role of muscle proteolysis. These investigations lead to finding important differences from denervation and atrophy and to define the roles of cytosolic versus lysosomal proteolysis in these atrophy models. A major outgrowth of these studies was demonstrating an ability to prevent atrophy of the unweighted muscle for at least 24 hours. A large amount of work concentrated on carbohydrate metabolism and its regulation by insulin and catecholamines. Measurements focused on glucose transport, glycogen metabolism, and glucose oxidation. The grant was used to develop an important new in situ approach for studying protein metabolism, glucose transport, and hormonal effects which involves intramuscular injection of various agents for up to 24 hours. Another important consequence of this project was the development and flight of Physiological-Anatomical Rodent Experiment-1 (PARE-1), which was launched aboard Space Shuttle Discovery in September 1991. Detailed descriptions of these studies can be found in the 30 peer-reviewed publications, 15 non-reviewed publications, 4 reviews and 33 abstracts (total 82 publications) which were or are scheduled to be published as a result of this project. A listing of these publications grouped by area (i.e. amino acid metabolism, protein metabolism, carbohydrate metabolism, and space flight studies) are included.

  8. Mangiferin protects against adverse skeletal muscle changes and enhances muscle oxidative capacity in obese rats.

    Science.gov (United States)

    Acevedo, Luz M; Raya, Ana I; Martínez-Moreno, Julio M; Aguilera-Tejero, Escolástico; Rivero, José-Luis L

    2017-01-01

    Obesity-related skeletal muscle changes include muscle atrophy, slow-to-fast fiber-type transformation, and impaired mitochondrial oxidative capacity. These changes relate with increased risk of insulin resistance. Mangiferin, the major component of the plant Mangifera indica, is a well-known anti-inflammatory, anti-diabetic, and antihyperlipidemic agent. This study tested the hypothesis that mangiferin treatment counteracts obesity-induced fiber atrophy and slow-to-fast fiber transition, and favors an oxidative phenotype in skeletal muscle of obese rats. Obese Zucker rats were fed gelatin pellets with (15 mg/kg BW/day) or without (placebo group) mangiferin for 8 weeks. Lean Zucker rats received the same gelatin pellets without mangiferin and served as non-obese and non-diabetic controls. Lesser diameter, fiber composition, and histochemical succinic dehydrogenase activity (an oxidative marker) of myosin-based fiber-types were assessed in soleus and tibialis cranialis muscles. A multivariate discriminant analysis encompassing all fiber-type features indicated that obese rats treated with mangiferin displayed skeletal muscle phenotypes significantly different compared with both lean and obese control rats. Mangiferin significantly decreased inflammatory cytokines, preserved skeletal muscle mass, fiber cross-sectional size, and fiber-type composition, and enhanced muscle fiber oxidative capacity. These data demonstrate that mangiferin attenuated adverse skeletal muscle changes in obese rats.

  9. Mangiferin protects against adverse skeletal muscle changes and enhances muscle oxidative capacity in obese rats

    Science.gov (United States)

    Acevedo, Luz M.; Raya, Ana I.; Martínez-Moreno, Julio M.

    2017-01-01

    Obesity-related skeletal muscle changes include muscle atrophy, slow-to-fast fiber-type transformation, and impaired mitochondrial oxidative capacity. These changes relate with increased risk of insulin resistance. Mangiferin, the major component of the plant Mangifera indica, is a well-known anti-inflammatory, anti-diabetic, and antihyperlipidemic agent. This study tested the hypothesis that mangiferin treatment counteracts obesity-induced fiber atrophy and slow-to-fast fiber transition, and favors an oxidative phenotype in skeletal muscle of obese rats. Obese Zucker rats were fed gelatin pellets with (15 mg/kg BW/day) or without (placebo group) mangiferin for 8 weeks. Lean Zucker rats received the same gelatin pellets without mangiferin and served as non-obese and non-diabetic controls. Lesser diameter, fiber composition, and histochemical succinic dehydrogenase activity (an oxidative marker) of myosin-based fiber-types were assessed in soleus and tibialis cranialis muscles. A multivariate discriminant analysis encompassing all fiber-type features indicated that obese rats treated with mangiferin displayed skeletal muscle phenotypes significantly different compared with both lean and obese control rats. Mangiferin significantly decreased inflammatory cytokines, preserved skeletal muscle mass, fiber cross-sectional size, and fiber-type composition, and enhanced muscle fiber oxidative capacity. These data demonstrate that mangiferin attenuated adverse skeletal muscle changes in obese rats. PMID:28253314

  10. 肌筋膜疼痛伴开口受限患者咬肌肌电图研究%Electromyography Analysis on Masseter Muscles in Myofacial Pain Syndrome Patients with Limited Mouth Opening

    Institute of Scientific and Technical Information of China (English)

    张非煜; 吕亚林; 董坚; 张杰夫; 李俨

    2013-01-01

    Objective: To analyze the surface electromyography (EMG) data of masseter muscles (MM) in patients with temporomandibular joint myofascial pain and anterior disk displacement without reduction (ADDWR). Methods: Twenty patients diagnosed with muscular TMD( ADDWR) by clinical examination were selected as experimental group. Ten people checked without TMD were selected as contrast group. EMG data MM of both groups were recorded and analyzed at mandibular postural position (MPP) and maximum contacted intercuspal position (ICP). The data were analyzed by 2 -way repeated-measures ANOVA and means were compared by SNK test (P<0. 05). Results: At MPP,patients' EMG potentials showed the significantly greater root mean square (RMS) of bilateral MM comparing with those of the control group MM (P<0. 01). At ICP, RMS of the bilateral MM of the experimental group was significantly less (P<0. 01). At MPP,patients' median frequency (MF) shows significantly less (P

  11. Body position effects on sternocleidomastoid and masseter EMG pattern activity in patients undergoing occlusal splint therapy.

    Science.gov (United States)

    Ormeño, G; Miralles, R; Santander, H; Casassus, R; Ferrer, P; Palazzi, C; Moya, H

    1997-10-01

    This study was conducted in order to determine the effects of body position on electromyographic (EMG) activity of sternocleidomastoid and masseter muscles, in 15 patients with myogenic cranio-cervical-mandibular dysfunction undergoing occlusal splint therapy. EMG activity was recorded by placing surface electrodes on the sternocleidomastoid and masseter muscles (contralateral to the habitual sleeping side of each patient). EMG activity at rest and during swallowing of saliva and maximal voluntary clenching was recorded in the following body positions: standing, supine and lateral decubitus. In the sternocleidomastoid muscle significant higher EMG activities at rest and during swallowing were recorded in the lateral decubitus position, whereas during maximal voluntary clenching EMG activity did not change. In the masseter muscle significant higher EMG activity during maximal voluntary clenching in a standing position was observed, whereas EMG activity at rest and during swallowing did not change. The opposite pattern of EMG activity supports the idea that there may exist a differential modulation of the motor neuron pools of the sternocleidomastoid and masseter muscles, of peripheral and/or central origin. This suggests that the presence of parafunctional habits and body position could be closely correlated with the clinical symptomatology in these muscles in patients with myogenic craniomandibular dysfunction.

  12. Muscle and liver glycogen, protein, and triglyceride in the rat

    DEFF Research Database (Denmark)

    Richter, Erik; Sonne, Bente; Joensen Mikines, Kari

    1984-01-01

    in skeletal muscle was accompanied by increased breakdown of triglyceride and/or protein. Thus, the effect of exhausting swimming and of running on concentrations of glycogen, protein, and triglyceride in skeletal muscle and liver were studied in rats with and without deficiencies of the sympatho......-adrenal system. In control rats, both swimming and running decreased the concentration of glycogen in fast-twitch red and slow-twitch red muscle whereas concentrations of protein and triglyceride did not decrease. In the liver, swimming depleted glycogen stores but protein and triglyceride concentrations did...... not decrease. In exercising rats, muscle glycogen breakdown was impaired by adrenodemedullation and restored by infusion of epinephrine. However, impaired glycogen breakdown during exercise was not accompanied by a significant net breakdown of protein or triglyceride. Surgical sympathectomy of the muscles did...

  13. Carboxylic ester hydrolases in mitochondria from rat skeletal muscle

    DEFF Research Database (Denmark)

    Kirkeby, S; Moe, D; Zelander, T

    1990-01-01

    A mitochondrial pellet, prepared from rat skeletal muscle, contained a number of carboxylic ester hydrolase isoenzymes. The esterases which split alpha-naphthyl acetate were organophosphate sensitive, whereas two out of three indoxyl acetate hydrolysing enzymes were resistant to both organophosph......A mitochondrial pellet, prepared from rat skeletal muscle, contained a number of carboxylic ester hydrolase isoenzymes. The esterases which split alpha-naphthyl acetate were organophosphate sensitive, whereas two out of three indoxyl acetate hydrolysing enzymes were resistant to both...

  14. The influence of flow redistribution on working rat muscle oxygenation

    NARCIS (Netherlands)

    Hoofd, L.J.C.; Degens, H.

    2009-01-01

    We applied a theoretical model of muscle tissue O2 transport to investigate the effects of flow redistribution on rat soleus muscle oxygenation. The situation chosen was the anaerobic threshold where redistribution of flow is expected to have the largest impact. In the basic situation all

  15. Clenching and grinding: effect on masseter and sternocleidomastoid electromyographic activity in healthy subjects.

    Science.gov (United States)

    Venegas, Macarena; Valdivia, José; Fresno, María Javiera; Miralles, Rodolfo; Gutiérrez, Mario Felipe; Valenzuela, Saúl; Fuentes, Aler

    2009-07-01

    This study compares the effect of clenching and grinding on masseter and sternocleidomastoid electromyographic (EMG) activity during different jaw posture tasks in the sagittal plane. The study included 34 healthy subjects with natural dentition, Class I bilateral molar Angle relationship, and absence of posterior occlusal contacts during mandibular protrusion. An inclusion criterion was that subjects had to be free of signs and symptoms of any dysfunction of the masticatory system. Bipolar surface electrodes were located on the right masseter and sternocleidomastoid muscles. EMG activity was recorded while the subjects were in standing position, during the following jaw posture tasks: A. maximal clenching in the intercuspal position; B. grinding from intercuspal position to edge-to-edge protrusive contact position; C. maximal clenching in the edge-to-edge protrusive contact position; D. grinding from edge-to-edge protrusive contact position to intercuspal position; E. grinding from retrusive contact position to intercuspal position. EMG activities in tasks B, C, D, and E were significantly lower than in task A in both muscles (mixed model with unstructured covariance matrix). EMG activity among tasks B, C, D, and E did not show significant differences in both muscles, except between tasks D and E in the masseter muscle. A higher effect was observed on the masseter than on the sternocleidomastoid muscle to avoid excessive muscular activity during clenching and grinding. The EMG patterns observed could be of clinical importance in the presence of parafunctional habits, i.e., clenching and/or grinding.

  16. Leucine supplementation improves regeneration of skeletal muscles from old rats.

    Science.gov (United States)

    Pereira, Marcelo G; Silva, Meiricris T; da Cunha, Fernanda M; Moriscot, Anselmo S; Aoki, Marcelo S; Miyabara, Elen H

    2015-12-01

    The decreased regenerative capacity of old skeletal muscles involves disrupted turnover of proteins. This study investigated whether leucine supplementation in old rats could improve muscle regenerative capacity. Young and old male Wistar rats were supplemented with leucine; then, the muscles were cryolesioned and examined after 3 and 10 days. Leucine supplementation attenuated the decrease in the expression of eukaryotic translation initiation factor 4E binding protein 1 (4E-BP1) and eukaryotic translation initiation factor 4E (eIF4E) in young and old muscles on day 3 post-injury and promoted an increase in the cross-sectional area of regenerating myofibers from both young and old soleus muscles on day 10 post-injury. This supplementation decreased the levels of ubiquitinated proteins and increased the proteasome activity in young regenerating muscles, but the opposite effect was observed in old regenerating muscles. Moreover, leucine decreased the inflammation area and induced an increase in the number of proliferating satellite cells in both young and old muscles. Our results suggest that leucine supplementation improves the regeneration of skeletal muscles from old rats, through the preservation of certain biological responses upon leucine supplementation. Such responses comprise the decrease in the inflammation area, increase in the number of proliferating satellite cells and size of regenerating myofibers, combined with the modulation of components of the phosphoinositide 3-kinase/Akt-protein kinase B/mammalian target of rapamycin (PI3K/Akt/mTOR) pathway and ubiquitin-proteasome system.

  17. THREE INTERMITTENT SESSIONS OF CRYOTHERAPY REDUCE THE SECONDARY MUSCLE INJURY IN SKELETAL MUSCLE OF RAT

    Directory of Open Access Journals (Sweden)

    Nuno M. L. Oliveira

    2006-06-01

    Full Text Available Although cryotherapy associated to compression is recommended as immediate treatment after muscle injury, the effect of intermittent sessions of these procedures in the area of secondary muscle injury is not established. This study examined the effect of three sessions of cryotherapy (30 min of ice pack each 2h and muscle compression (sand pack in the muscle-injured area. Twenty-four Wistar rats (312 ± 20g were evaluated. In three groups, the middle belly of tibialis anterior (TA muscle was injured by a frozen iron bar and received one of the following treatments: a three sessions of cryotherapy; b three sessions of compression; c not treated. An uninjured group received sessions of cryotherapy. Frozen muscles were cross- sectioned (10 µm and stained for the measurement of injured and uninjured muscle area. Injured muscles submitted to cryotherapy showed the smallest injured area (29.83 ± 6.6%, compared to compressed (39.2 ± 2.8%, p= 0.003 and untreated muscles (41.74 ± 4.0%, p = 0.0008. No difference was found between injured compressed and injured untreated muscles. In conclusion, three intermittent sessions of cryotherapy applied immediately after muscle damage was able to reduce the secondary muscle injury, while only the muscle compression did not provide the same effectiveness

  18. Conventional versus implant-retained overlay dentures: a pilot study of masseter and anterior temporalis electromyography.

    Science.gov (United States)

    Dakhilalian, Mansour; Rismanchian, Mansour; Fazel, Akbar; Basiri, Keyvan; Azadeh, Hamid; Mahmoodi, Maryam; Fayazi, Sara; Sadr-Eshkvari, Pooyan

    2014-08-01

    Implant-supported overlay dentures (ISODs) have been widely accepted among patients using conventional removable complete dentures (CRCDs). The present study aimed to comparatively study conventional and ISODs in terms of function and coordination of masticatory muscles using electromyograms. Included were 10 patients with ISODs (each with 2 implants in the intercanine area). The mean wave range (MWR) and frequency (MWF) of masseter and temporalis were recorded with (ISOD) and without (CRCD) ball attachments while maximum clenching on cotton rolls (cotton roll clenching), maximum intercuspal clenching (clenching), and unilateral gum chewing (chewing) using electromyography. Data were analyzed in SPAW using t-paired for matched groups and independent-sample t tests for unmatched ones. The MWF differences were not statistically significant with or without attachments (P > .05). Without attachments in place, the MWF of both masseter and temporalis muscles significantly decreased when patients clenched on cotton rolls (P = .01 and .02, respectively) and when chewing unilaterally (both P = .01). With attachments present, the right and left temporalis muscles did not show identical mean wave ranges while chewing (P = .01). Without attachments, this disharmony was seen in the left and right masseter muscles (P = .03). The MWR of masseter was higher in men while chewing with attachments (P = .02). Without attachments, the MWR of temporalis was higher in women while cotton roll clenching (P = .03) and chewing (P = .02). These findings are seemingly in favor of improved masticatory function and coordination in edentulous patients with the application of ISODs.

  19. CONTRACTION CHARACTERISTICS AND MYOSIN HEAVY-CHAIN COMPOSITION OF RABBIT MASSETER MOTOR UNITS

    NARCIS (Netherlands)

    KWA, SHS; WEIJS, WA; JUCH, PJW

    1995-01-01

    1. We studied isometric twitch peak force (TPF) and twitch contraction time (TCT) of 249 motor units of the masseter muscle in 41 rabbits after extracellular electrical stimulation of single trigeminal motoneurons in the brain stem. In 41 of these units we determined the amount of tension decrease d

  20. The effect of age on rat rotator cuff muscle architecture.

    Science.gov (United States)

    Swan, Malcolm A; Sato, Eugene; Galatz, Leesa M; Thomopoulos, Stavros; Ward, Samuel R

    2014-12-01

    Understanding rotator cuff muscle function during disease development and after repair is necessary for preventing degeneration and improving postsurgical outcomes, respectively. The rat is a commonly used rotator cuff animal model; however, unlike humans, rats continue to grow throughout their lifespan, so age-related changes in muscle structure may complicate an understanding of muscle adaptations to injury. Infraspinatus and supraspinatus muscle mass, fiber length, pennation angle, sarcomere length, and physiological cross-sectional area (PCSA) were measured in Sprague-Dawley rats (n = 30) with a body mass ranging from 51 to 814 g (approximately 3 weeks to approximately 18 months). Both the supraspinatus and infraspinatus showed a striking conservation of sarcomere length throughout growth. There was linear growth in muscle mass and PCSA, nonlinear growth in muscle length and fiber bundle length, and a linear relationship between humeral head diameter and fiber bundle length, suggesting that muscle fiber length (serial sarcomere number) adjusted according to skeletal dimensions. These muscle growth trajectories allowed sarcomere length to remain nearly constant. During the typical rat rotator cuff experimental period (animal mass, 400-600 g), muscle mass will increase by 30%, fiber length will increase by 7%, and PCSA will increase by 27%, but sarcomere lengths are nearly constant. Therefore, these normal growth-induced changes in architecture must be considered when muscle atrophy or fiber shortening is measured after rotator cuff tears in this model. Copyright © 2014 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.

  1. Effect of salbutamol on innervated and denervated rat soleus muscle

    Directory of Open Access Journals (Sweden)

    ?oic-Vranic T.

    2005-01-01

    Full Text Available The objective of the present investigation was to perform a 14-day time-course study of treatment with salbutamol, a ß2 adrenoceptor agonist, on rat soleus muscle in order to assess fiber type selectivity in the hypertrophic response and fiber type composition. Male Wistar rats were divided into four groups: control (N = 10, treated with salbutamol (N = 30, denervated (N = 30, and treated with salbutamol after denervation (N = 30. Salbutamol was injected intraperitoneally in the rats of the 2nd and 4th groups at a concentration of 0.3 mg/kg twice a day for 2 weeks. The muscles were denervated using the crush method with pean. The animals were sacrificed 3, 6, 9, 12, and 14 days after treatment. Frozen cross-sections of soleus muscle were stained for myosin ATPase, pH 9.4. Cross-sectional area and percent of muscle fibers were analyzed morphometrically by computerized image analysis. Treatment with salbutamol induced hypertrophy of all fiber types and a higher percentage of type II fibers (21% in the healthy rat soleus muscle. Denervation caused marked atrophy of all fibers and conversion from type I to type II muscle fibers. Denervated muscles treated with salbutamol showed a significantly larger cross-sectional area of type I muscle fibers, 28.2% compared to the denervated untreated muscle. Moreover, the number of type I fibers was increased. These results indicate that administration of salbutamol is able to induce changes in cross-sectional area and fiber type distribution in the early phase of treatment. Since denervation-induced atrophy and conversion from type I to type II fibers were improved by salbutamol treatment we propose that salbutamol, like other ß2 adrenoceptor agonists, may have a therapeutic potential in improving the condition of skeletal muscle after denervation.

  2. Dihydroartemisinin-Stimulated Hyperplasia of Rat Lung Smooth Muscles

    Directory of Open Access Journals (Sweden)

    Utoh-Nedosa U. Anastasia

    2012-01-01

    Full Text Available Problem statement: Dihydroartemisinin was shown to produce two types of inhibitory effects on the cardiac muscles of rats. It was also shown to stimulate haemopoiesis in the lungs, liver, spleen, intestine and kidney of rats. This study attempted to find out the nature of the effect of oral dihydroartemisinin on the lungs of Wistar albino rats. Approach: The effects of dihydroartemisinin on the tissues of the lungs of wistar albino rats were investigated with five doses of Dihydroartemisinin (DHA administered for 5 days by oral intubation. The five tested doses were 1 mg kg-1, a repeated dose of 1, 2, 60 and 80 mg kg-1 DHA. Results: Histopathological examination of the tissue micrographs of the lungs of the dihydroartemisinin treated rats showed that in comparism with those of the controls, DHA had no adverse effects on the tissues of the lungs of the rats but rather produced a direct stimulatory effect on the smooth muscles of the lungs. This stimulation caused hyperplasia of these tissues which was observable histologically in tissue micrographs of the lungs. These effects of dihydroartemisinin on the tissues of the lungs of Wistar albino rats were dose, repetition and time dependent. Conclusion: These growth hormone-like stimulatory effects of dihydroartemisinin on the smooth muscles of the lungs suggest that DHA enhanced the functioning capacity of the lungs of the DHA-treated rats. These results suggest that dihydroartemisinin has possible respiration enhancement effects.

  3. Avaliação eletromiográfica com eletrodos de captação de superfície dos músculos masseter, temporal e bucinador de lactentes em situação de aleitamento natural e artificial Surface electromyography of facial muscles during natural and artificial feeding of infants

    Directory of Open Access Journals (Sweden)

    Cristiane F. Gomes

    2006-04-01

    Full Text Available OBJETIVO: Mensurar e comparar a atividade dos músculos masseter, temporal e bucinador em diferentes métodos de alimentação de lactentes. MÉTODO: Estudo transversal, com participação de 60 lactentes nascidos a termo e sem intercorrências, entre 2 e 3 meses de idade, divididos em três grupos: 1 aleitamento materno exclusivo; 2 aleitamento misto com uso de mamadeira; e 3 aleitamento materno exclusivo com uso de copo. Foi realizada eletromiografia com eletrodos de captação de superfície durante a alimentação. O teste estatístico utilizado é o Kruskal-Wallis, complementado com as comparações múltiplas entre pares de grupos, e todas as discussões são realizadas no nível de 5% de significância. RESULTADOS: Verificam-se maiores resultados no grupo de aleitamento materno em relação ao grupo de aleitamento por mamadeira, tanto na amplitude quanto na média de contração do músculo masseter. No que se refere ao músculo temporal, há resultados maiores na amplitude do grupo de aleitamento materno e na média de contração do grupo de aleitamento por copo, quando comparados ao grupo de aleitamento por mamadeira. Quanto ao músculo bucinador, observam-se resultados maiores no grupo de aleitamento por mamadeira com relação ao aleitamento materno, sendo que tal diferença ocorre apenas na amplitude de contração. CONCLUSÃO: As semelhanças entre a atividade muscular do grupo de aleitamento materno e aleitamento por copo permitem sugerir o uso do copo como método alternativo na alimentação de lactentes, ao contrário do aleitamento por mamadeira, devido à hiperfunção do músculo bucinador, podendo resultar em alterações motoras orais e das funções neurovegetativas.OBJECTIVE: To measure and compare the activity of the masseter, temporalis and buccinator muscles in different infant feeding methods METHODS: Cross-sectional study of 60 full-term infants with no intercurrent diseases, aged between two and three months

  4. Modulation of an inhibitory reflex in single motor units in human masseter by tonic painful stimulation.

    Science.gov (United States)

    Svensson, P; McMillan, A S; Graven-Nielsen, T; Wang, K; Arendt-Nielsen, L

    1999-12-01

    Perioral electrical stimuli cause inhibitory reflex responses in single motor-units (SMU) and surface electromyographic (EMG) recordings from voluntary contracted human jaw-closing muscles. Tonic experimental masseter pain has recently been shown to reduce the inhibitory reflex response in surface EMG recordings but the effect on SMU activity has not been described. In this study, motor-unit action potentials were recorded with wire electrodes inserted into the left masseter in eleven subjects. The subjects kept the SMU firing rate around 10 Hz by feedback. Ninety-nine electrical stimuli were applied sequentially to the left mental nerve with increasing stimulus delays in steps of 1 ms after the preceding motor unit action potential. The inhibitory reflex in SMU was recorded before, during and after infusion of hypertonic saline (5%) into the ipsilateral masseter muscle. Spike train data were used to calculate (1) the mean pre- and post-stimulus inter-spike-intervals (ISI) in all of the 99 trials, (2) cumulative changes in firing probability, and (3) estimation of the compound inhibitory post-synaptic potential (IPSP) in the masseter motoneuron. Tonic masseter pain did not change pre-stimulus SMU firing characteristics but the mean ISI for the first post-stimulus discharge (158.2+/-9.2 ms) was significantly decreased compared to the pre-pain (175.8+/-11.3 ms, Pmasseter pain compared to pre-pain and post-pain conditions. In conclusion, this study indicates that tonic masseter pain has a net excitatory effect on the inhibitory jaw-reflexes, which could be mediated by presynaptic mechanisms on the involved motoneurons.

  5. Ultrastructural organization of muscle fiber types and their distribution in the rat superior rectus extraocular muscle.

    Science.gov (United States)

    Rashed, Rashed M; El-Alfy, Sherif H

    2012-05-01

    Extraocular muscles (EOMs) are unique as they show greater variation in anatomical and physiological properties than any other skeletal muscles. To investigate the muscle fiber types and to understand better the structure-function correlation of the extraocular muscles, the present study examined the ultrastructural characteristics of the superior rectus muscle of rat. The superior rectus muscle is organized into two layers: a central global layer of mainly large-diameter fibers and an outer C-shaped orbital layer of principally small-diameter fibers. Six morphologically distinct fiber types were identified within the superior rectus muscle. Four muscle fiber types, three single innervated fibers (SIFs) and one multiple innervated fiber (MIF), were recognized in the global layer. The single innervated fibers included red, white and intermediate fibers. They differed from one another with respect to diameter, mitochondrial size and distribution, sarcoplasmic reticulum and myofibrillar size. The orbital layer contained two distinct MIFs in addition to the red and intermediate SIFs. The orbital MIFs were categorized into low oxidative and high oxidative types according to their mitochondrial content and distribution. The highly specialized function of the superior rectus extraocular muscle is reflected in the multiplicity of its fiber types, which exhibit unique structural features. The unique ultrastructural features of the extraocular muscles and their possible relation to muscle function are discussed. Copyright © 2011 Elsevier GmbH. All rights reserved.

  6. Passive stiffness of rat skeletal muscle undernourished during fetal development

    Directory of Open Access Journals (Sweden)

    Ana Elisa Toscano

    2010-01-01

    Full Text Available OBJECTIVES: The aim of the study was to investigate the effect of fetal undernutrition on the passive mechanical properties of skeletal muscle of weaned and young adult rats. INTRODUCTION: A poor nutrition supply during fetal development affects physiological functions of the fetus. From a mechanical point of view, skeletal muscle can be also characterized by its resistance to passive stretch. METHODS: Male Wistar rats were divided into two groups according to their mother's diet during pregnancy: a control group (mothers fed a 17% protein diet and an isocaloric low-protein group (mothers fed a 7.8% protein diet. At birth, all mothers received a standardized meal ad libitum. At the age of 25 and 90 days, the soleus muscle and extensor digitorum longus (EDL muscles were removed in order to test the passive mechanical properties. A first mechanical test consisted of an incremental stepwise extension test using fast velocity stretching (500 mm/s enabling us to measure, for each extension stepwise, the dynamic stress (σd and the steady stress (σs. A second test consisted of a slow velocity stretch in order to calculate normalized stiffness and tangent modulus from the stress-strain relationship. RESULTS: The results for the mechanical properties showed an important increase in passive stiffness in both the soleus and EDL muscles in weaned rat. In contrast, no modification was observed in young adult rats. CONCLUSIONS: The increase in passive stiffness in skeletal muscle of weaned rat submitted to intrauterine undernutrition it is most likely due to changes in muscle passive stiffness.

  7. [Effect of prednisolon on trachea smooth muscle of normal rats and rats with fibrosing alveolitis].

    Science.gov (United States)

    Fedin, A N; Nekrasova, E A; Frolova, S A; Danilov, L N; Lebedeva, E S; Il'kovich, M M

    2007-01-01

    Effect of prednisolone on isolated preparations of trachea of normal rats and rats with fibrosing alveolitis was studied. Prednisolone at a concentration of 0.4 microg/l decreased responses of smooth muscle on stimulation of preganglionar nerve fibers at trachea areas with intramural ganglia in rats with acute alveolitis by 48%, while in normal rats--by 19% of control. In trachea preparations without ganglia, prednisolone at a dose of 10 microg/l decreased responses of muscle to the nerve fiber stimulation by 21.3%. The higher prednisolone doses were less efficient: 0.1-10 microg/l glucocorticoid practically did not affect the smooth muscle responses produced by stimulation of muscle cells. In rats with fibrosing alveolitis, 10 microg/l prednisolone restored the smooth muscle responses to control values in preparations of trachea with intramural ganglia. After the prednisolone treatment, amplitude of the rat trachea muscle contraction in response to the nerve fiber electric stimulation did not differ statistically significantly from control and 0.1-10 microg/l prednisolone did not change the response value. The conclusion is made that prednisolone affected the diseased rats more efficiently than the healthy animals. The character of the glucocorticoid effect depends on the presence of intramural ganglia in the trachea wall.

  8. Ureter smooth muscle cell orientation in rat is predominantly longitudinal.

    Directory of Open Access Journals (Sweden)

    Bart Spronck

    Full Text Available In ureter peristalsis, the orientation of the contracting smooth muscle cells is essential, yet current descriptions of orientation and composition of the smooth muscle layer in human as well as in rat ureter are inconsistent. The present study aims to improve quantification of smooth muscle orientation in rat ureters as a basis for mechanistic understanding of peristalsis. A crucial step in our approach is to use two-photon laser scanning microscopy and image analysis providing objective, quantitative data on smooth muscle cell orientation in intact ureters, avoiding the usual sectioning artifacts. In 36 rat ureter segments, originating from a proximal, middle or distal site and from a left or right ureter, we found close to the adventitia a well-defined longitudinal smooth muscle orientation. Towards the lamina propria, the orientation gradually became slightly more disperse, yet the main orientation remained longitudinal. We conclude that smooth muscle cell orientation in rat ureter is predominantly longitudinal, though the orientation gradually becomes more disperse towards the proprial side. These findings do not support identification of separate layers. The observed longitudinal orientation suggests that smooth muscle contraction would rather cause local shortening of the ureter, than cause luminal constriction. However, the net-like connective tissue of the ureter wall may translate local longitudinal shortening into co-local luminal constriction, facilitating peristalsis. Our quantitative, minimally invasive approach is a crucial step towards more mechanistic insight into ureter peristalsis, and may also be used to study smooth muscle cell orientation in other tube-like structures like gut and blood vessels.

  9. Angiotensin II induces differential insulin action in rat skeletal muscle.

    Science.gov (United States)

    Surapongchai, Juthamard; Prasannarong, Mujalin; Bupha-Intr, Tepmanas; Saengsirisuwan, Vitoon

    2017-03-01

    Angiotensin II (ANGII) is reportedly involved in the development of skeletal muscle insulin resistance. The present investigation evaluated the effects of two ANGII doses on the phenotypic characteristics of insulin resistance syndrome and insulin action and signaling in rat skeletal muscle. Male Sprague-Dawley rats were infused with either saline (SHAM) or ANGII at a commonly used pressor dose (100 ng/kg/min; ANGII-100) or a higher pressor dose (500 ng/kg/min; ANGII-500) via osmotic minipumps for 14 days. We demonstrated that ANGII-100-infused rats exhibited the phenotypic features of non-obese insulin resistance syndrome, including hypertension, impaired glucose tolerance and insulin resistance of glucose uptake in the soleus muscle, whereas ANGII-500-treated rats exhibited diabetes-like symptoms, such as post-prandial hyperglycemia, impaired insulin secretion and hypertriglyceridemia. At the cellular level, insulin-stimulated glucose uptake in the soleus muscle of the ANGII-100 group was 33% lower (P study demonstrates for the first time that chronic infusion with these two pressor doses of ANGII induced differential metabolic responses at both the systemic and skeletal muscle levels.

  10. Abdominal expiratory muscle activity in anesthetized vagotomized neonatal rats.

    Science.gov (United States)

    Iizuka, Makito

    2009-05-01

    The pattern of respiratory activity in abdominal muscles was studied in anesthetized, spontaneously breathing, vagotomized neonatal rats at postnatal days 0-3. Anesthesia (2.0% isoflurane, 50% O(2)) depressed breathing and resulted in hypercapnia. Under this condition, abdominal muscles showed discharge late in the expiratory phase (E2 activity) in most rats. As the depth of anesthesia decreased, the amplitude of discharges in the diaphragm and abdominal muscles increased. A small additional burst frequently occurred in abdominal muscles just after the termination of diaphragmatic inspiratory activity (E1 or postinspiratory activity). Since this E1 activity is not often observed in adult rats, the abdominal respiratory pattern likely changes during postnatal development. Anoxia-induced gasping after periodic expiratory activity without inspiratory activity, and in most rats, abdominal expiratory activity disappeared before terminal apnea. These results suggest that a biphasic abdominal motor pattern (a combination of E2 and E1 activity) is a characteristic of vagotomized neonatal rats during normal respiration.

  11. Endogenous L-Carnosine Level in Diabetes Rat Cardiac Muscle

    Directory of Open Access Journals (Sweden)

    Yali Liu

    2016-01-01

    Full Text Available A novel method for quantitation of cardiac muscle carnosine levels using HPLC-UV is described. In this simple and reliable method, carnosine from the rat cardiac muscle and the internal standard, thymopentin, were extracted by protein precipitation with acetonitrile. The method was linear up to 60.96 μg·mL−1 for L-carnosine. The calibration curve was linear in concentration ranges from 0.5 to 60.96 μg·mL−1. The relative standard deviations obtained for intra- and interday precision were lower than 12% and the recoveries were higher than 90% for both carnosine and internal standard. We successfully applied this method to the analysis of endogenous carnosine in cardiac muscle of the diabetes rats and healthy control rats. The concentration of carnosine was significantly lower in the diabetes rats group, compared to that in the healthy control rats. These results support the usefulness of this method as a means of quantitating carnosine and illustrate the important role of L-carnosine in cardiac muscle.

  12. Endurance training facilitates myoglobin desaturation during muscle contraction in rat skeletal muscle.

    Science.gov (United States)

    Takakura, Hisashi; Furuichi, Yasuro; Yamada, Tatsuya; Jue, Thomas; Ojino, Minoru; Hashimoto, Takeshi; Iwase, Satoshi; Hojo, Tatsuya; Izawa, Tetsuya; Masuda, Kazumi

    2015-03-24

    At onset of muscle contraction, myoglobin (Mb) immediately releases its bound O2 to the mitochondria. Accordingly, intracellular O2 tension (PmbO2) markedly declines in order to increase muscle O2 uptake (mVO2). However, whether the change in PmbO2 during muscle contraction modulates mVO2 and whether the O2 release rate from Mb increases in endurance-trained muscles remain unclear. The purpose of this study was, therefore, to determine the effect of endurance training on O2 saturation of Mb (SmbO2) and PmbO2 kinetics during muscle contraction. Male Wistar rats were subjected to a 4-week swimming training (Tr group; 6 days per week, 30 min × 4 sets per day) with a weight load of 2% body mass. After the training period, deoxygenated Mb kinetics during muscle contraction were measured using near-infrared spectroscopy under hemoglobin-free medium perfusion. In the Tr group, the VmO2peak significantly increased by 32%. Although the PmbO2 during muscle contraction did not affect the increased mVO2 in endurance-trained muscle, the O2 release rate from Mb increased because of the increased Mb concentration and faster decremental rate in SmbO2 at the maximal twitch tension. These results suggest that the Mb dynamics during muscle contraction are contributing factors to faster VO2 kinetics in endurance-trained muscle.

  13. Rat gracilis muscle preparation for combined macro- and microvascular research.

    Science.gov (United States)

    Swain, D P; Lalone, B J

    1982-04-01

    A skeletal muscle preparation for the study of single vessel and whole organ vascular responses is presented. After surgical isolation from anesthetized rats, the gracilis muscle preparation is autoperfused via cannulation circuits. This allows the measurement of, and experimental control over, such macrovascular parameters as arterial and venous pressures and total muscle blood flow. In addition, the preparation is thin enough to allow the simultaneous study of microvessels by transilluminated microscopy. Such dual capabilities allow the preparation to be used in a wide variety of investigations and, in particular, as a primary tool in correlating microcirculatory responses with those of the whole organ in experiments designed to elucidate local control mechanisms of skeletal muscle vasculature. An example of such is demonstrated for reactive hyperemia responses simultaneously obtained at arteriolar and muscle venous effluent locations.

  14. Alpha-adrenergic receptors in rat skeletal muscle

    DEFF Research Database (Denmark)

    Rattigan, S; Appleby, G J; Edwards, S J;

    1986-01-01

    Sarcolemma-enriched preparations from muscles rich in slow oxidative red fibres contained specific binding sites for the alpha 1 antagonist, prazosin (e.g. soleus Kd 0.13 nM, Bmax 29 fmol/mg protein). Binding sites for prazosin were almost absent from white muscle. Displacement of prazosin bindin...... adrenergic receptors are present on the sarcolemma of slow oxidative red fibres of rat skeletal muscle. The presence provides the mechanistic basis for apparent alpha-adrenergic effects to increase glucose and oxygen uptake in perfused rat hindquarter.......Sarcolemma-enriched preparations from muscles rich in slow oxidative red fibres contained specific binding sites for the alpha 1 antagonist, prazosin (e.g. soleus Kd 0.13 nM, Bmax 29 fmol/mg protein). Binding sites for prazosin were almost absent from white muscle. Displacement of prazosin binding...... from sarcolemma of soleus muscle (phentolamine greater than phenylephrine greater than idazoxan greater than yohimbine) suggested that the receptors were alpha 1. Binding sites for dihydroalprenolol (beta antagonist) were also more concentrated on red than white muscle and outnumbered prazosin sites...

  15. Astaxanthin intake attenuates muscle atrophy caused by immobilization in rats.

    Science.gov (United States)

    Shibaguchi, Tsubasa; Yamaguchi, Yusuke; Miyaji, Nobuyuki; Yoshihara, Toshinori; Naito, Hisashi; Goto, Katsumasa; Ohmori, Daijiro; Yoshioka, Toshitada; Sugiura, Takao

    2016-08-01

    Astaxanthin is a carotenoid pigment and has been shown to be an effective inhibitor of oxidative damage. We tested the hypothesis that astaxanthin intake would attenuate immobilization-induced muscle atrophy in rats. Male Wistar rats (14-week old) were fed for 24 days with either astaxanthin or placebo diet. After 14 days of each experimental diet intake, the hindlimb muscles of one leg were immobilized in plantar flexion position using a plaster cast. Following 10 days of immobilization, both the atrophic and the contralateral plantaris muscles were removed and analyzed to determine the level of muscle atrophy along with measurement of the protein levels of CuZn-superoxide dismutase (CuZn-SOD) and selected proteases. Compared with placebo diet animals, the degree of muscle atrophy in response to immobilization was significantly reduced in astaxanthin diet animals. Further, astaxanthin supplementation significantly prevented the immobilization-induced increase in the expression of CuZn-SOD, cathepsin L, calpain, and ubiquitin in the atrophied muscle. These results support the postulate that dietary astaxanthin intake attenuates the rate of disuse muscle atrophy by inhibiting oxidative stress and proteolysis via three major proteolytic pathways. © 2016 The Authors. Physiological Reports published by Wiley Periodicals, Inc. on behalf of the American Physiological Society and The Physiological Society.

  16. A rat model for muscle regeneration in the soft palate.

    Directory of Open Access Journals (Sweden)

    Paola L Carvajal Monroy

    Full Text Available BACKGROUND: Children with a cleft in the soft palate have difficulties with speech, swallowing, and sucking. Despite successful surgical repositioning of the muscles, optimal function is often not achieved. Scar formation and defective regeneration may hamper the functional recovery of the muscles after cleft palate repair. Therefore, the aim of this study is to investigate the anatomy and histology of the soft palate in rats, and to establish an in vivo model for muscle regeneration after surgical injury. METHODS: Fourteen adult male Sprague Dawley rats were divided into four groups. Groups 1 (n = 4 and 2 (n = 2 were used to investigate the anatomy and histology of the soft palate, respectively. Group 3 (n = 6 was used for surgical wounding of the soft palate, and group 4 (n = 2 was used as unwounded control group. The wounds (1 mm were evaluated by (immunohistochemistry (AZAN staining, Pax7, MyoD, MyoG, MyHC, and ASMA after 7 days. RESULTS: The present study shows that the anatomy and histology of the soft palate muscles of the rat is largely comparable with that in humans. All wounds showed clinical evidence of healing after 7 days. AZAN staining demonstrated extensive collagen deposition in the wound area, and initial regeneration of muscle fibers and salivary glands. Proliferating and differentiating satellite cells were identified in the wound area by antibody staining. CONCLUSIONS: This model is the first, suitable for studying muscle regeneration in the rat soft palate, and allows the development of novel adjuvant strategies to promote muscle regeneration after cleft palate surgery.

  17. Muscle fiber viability, a novel method for the fast detection of ischemic muscle injury in rats.

    Science.gov (United States)

    Turóczi, Zsolt; Arányi, Péter; Lukáts, Ákos; Garbaisz, Dávid; Lotz, Gábor; Harsányi, László; Szijártó, Attila

    2014-01-01

    Acute lower extremity ischemia is a limb- and life-threatening clinical problem. Rapid detection of the degree of injury is crucial, however at present there are no exact diagnostic tests available to achieve this purpose. Our goal was to examine a novel technique - which has the potential to accurately assess the degree of ischemic muscle injury within a short period of time - in a clinically relevant rodent model. Male Wistar rats were exposed to 4, 6, 8 and 9 hours of bilateral lower limb ischemia induced by the occlusion of the infrarenal aorta. Additional animals underwent 8 and 9 hours of ischemia followed by 2 hours of reperfusion to examine the effects of revascularization. Muscle samples were collected from the left anterior tibial muscle for viability assessment. The degree of muscle damage (muscle fiber viability) was assessed by morphometric evaluation of NADH-tetrazolium reductase reaction on frozen sections. Right hind limbs were perfusion-fixed with paraformaldehyde and glutaraldehyde for light and electron microscopic examinations. Muscle fiber viability decreased progressively over the time of ischemia, with significant differences found between the consecutive times. High correlation was detected between the length of ischemia and the values of muscle fiber viability. After reperfusion, viability showed significant reduction in the 8-hour-ischemia and 2-hour-reperfusion group compared to the 8-hour-ischemia-only group, and decreased further after 9 hours of ischemia and 2 hours of reperfusion. Light- and electron microscopic findings correlated strongly with the values of muscle fiber viability: lesser viability values represented higher degree of ultrastructural injury while similar viability results corresponded to similar morphological injury. Muscle fiber viability was capable of accurately determining the degree of muscle injury in our rat model. Our method might therefore be useful in clinical settings in the diagnostics of acute ischemic

  18. Polyneural innervation in the psoas muscle of the developing rat

    NARCIS (Netherlands)

    Ijkema-Paassen, J; Gramsbergen, A

    1998-01-01

    Polyneural innervation was studied in the psoas muscle in developing rats from P4 till P25 and at adult age, with the combined silver-acetylcholinesterase technique. Nerve endings were counted, and endplates were measured. These data were compared with such data in the human. The end of polyneural i

  19. Masseter thickness, endurance and exercise-induced pain in subjects with different vertical craniofacial morphology.

    Science.gov (United States)

    Farella, Mauro; Bakke, Merete; Michelotti, Ambra; Rapuano, Alessia; Martina, Roberto

    2003-06-01

    The aim of the study was to compare neuromuscular features of the masseter muscle in subjects with different vertical craniofacial morphology. Fifteen short-faced (mandibular plane-Frankfurt plane angle or = 23 degrees) male students participated. The thickness of the masseter was assessed by ultrasonography. Onset and endurance of exercise pain were recorded during sustained biting at a level of 15% of maximum voluntary contraction and 30 micro V electromyographic activity. Pain and fatigue was measured on visual analog scales before and after the biting, as well as before and after 10 min chewing. Statistical comparison showed that the masseter muscle was significantly thicker (+15%) in the short-faced than the normal- to long-faced subjects. The pain onset time and endurance time were also consistently shorter in short-faced subjects, whereas the intensity of pain and fatigue did not differ significantly between the two groups. Multiple stepwise regression showed positive influence from the mandibular plane inclination and the masseter thickness on the pain onset time and endurance time. The present findings support the concept that subjects with different craniofacial morphology show neuromuscular differences.

  20. Purinergic effects on Na,K-ATPase activity differ in rat and human skeletal muscle

    DEFF Research Database (Denmark)

    Juel, Carsten; Nordsborg, Nikolai Baastrup; Bangsbo, Jens

    2014-01-01

    P2Y receptor activation may link the effect of purines to increased maximal in vitro activity of the Na,K-ATPase in rat muscle. The hypothesis that a similar mechanism is present in human skeletal muscle was investigated with membranes from rat and human skeletal muscle.......P2Y receptor activation may link the effect of purines to increased maximal in vitro activity of the Na,K-ATPase in rat muscle. The hypothesis that a similar mechanism is present in human skeletal muscle was investigated with membranes from rat and human skeletal muscle....

  1. Bone and muscle atrophy with suspension of the rat

    Science.gov (United States)

    Leblanc, A.; Marsh, C.; Evans, H.; Johnson, P.; Schneider, V.; Jhingran, S.

    1985-01-01

    In order to identify a suitable model for the study of muscle atrophy due to suspension in space, a modified version of the Morey tail suspension model was used to measure the atrophic responses of rat bone and muscle to 14-30 days of unloading of the hindlimbs. The progress of atrophy was measured by increases in methylene diphosphonate (MDP) uptake. It is found that bone uptake of methylene diphosphonate followed a phasic pattern similar to changes in the bone formation rate of immobilized dogs and cats. Increased MDP uptake after a period of 60 days indicated an accelerated bone metabolism. Maximum muscle atrophy in the suspended rats was distinctly different from immobilization atrophy. On the basis of the experimental results, it is concluded that the tail suspension model is an adequate simulation of bone atrophy due to suspension.

  2. Bone and muscle atrophy with suspension of the rat

    Science.gov (United States)

    Leblanc, A.; Marsh, C.; Evans, H.; Johnson, P.; Schneider, V.; Jhingran, S.

    1985-01-01

    In order to identify a suitable model for the study of muscle atrophy due to suspension in space, a modified version of the Morey tail suspension model was used to measure the atrophic responses of rat bone and muscle to 14-30 days of unloading of the hindlimbs. The progress of atrophy was measured by increases in methylene diphosphonate (MDP) uptake. It is found that bone uptake of methylene diphosphonate followed a phasic pattern similar to changes in the bone formation rate of immobilized dogs and cats. Increased MDP uptake after a period of 60 days indicated an accelerated bone metabolism. Maximum muscle atrophy in the suspended rats was distinctly different from immobilization atrophy. On the basis of the experimental results, it is concluded that the tail suspension model is an adequate simulation of bone atrophy due to suspension.

  3. Establishment of bipotent progenitor cell clone from rat skeletal muscle.

    Science.gov (United States)

    Murakami, Yousuke; Yada, Erica; Nakano, Shin-ichi; Miyagoe-Suzuki, Yuko; Hosoyama, Tohru; Matsuwaki, Takashi; Yamanouchi, Keitaro; Nishihara, Masugi

    2011-12-01

    The present study describes the isolation, cloning and characterization of adipogenic progenitor cells from rat skeletal muscle. Among the obtained 10 clones, the most highly adipogenic progenitor, 2G11 cells, were further characterized. In addition to their adipogenicity, 2G11 cells retain myogenic potential as revealed by formation of multinucleated myotubes when co-cultured with myoblasts. 2G11 cells were resistant to an inhibitory effect of basic fibroblast growth factor on adipogenesis, while adipogenesis of widely used preadipogenic cell line, 3T3-L1 cells, was suppressed almost completely by the same treatment. In vivo transplantation experiments revealed that 2G11 cells are able to possess both adipogenicity and myogenicity in vivo. These results indicate the presence of bipotent progenitor cells in rat skeletal muscle, and suggest that such cells may contribute to ectopic fat formation in skeletal muscle.

  4. Dexamethasone regulates glutamine synthetase expression in rat skeletal muscles

    Science.gov (United States)

    Max, Stephen R.; Konagaya, Masaaki; Konagaya, Yoko; Thomas, John W.; Banner, Carl; Vitkovic, Ljubisa

    1986-01-01

    The regulation of glutamine synthetase by glucocorticoids in rat skeletal muscles was studied. Administration of dexamethasone strikingly enhanced glutamine synthetase activity in plantaris and soleus muscles. The dexamethasone-mediated induction of glutamine synthetase activity was blocked to a significant extent by orally administered RU38486, a glucocorticoid antagonist, indicating the involvement of intracellular glucocorticoid receptors in the induction. Northern blot analysis revealed that dexamethasone-mediated enhancement of glutamine synthetase activity involves dramatically increased levels of glutamine synthetase mRNA. The induction of glutamine synthetase was selective in that glutaminase activity of soleus and plantaris muscles was not increased by dexamethasone. Furthermore, dexamethasone treatment resulted in only a small increase in glutamine synthetase activity in the heart. Accordingly, there was only a slight change in glutamine synthetase mRNA level in this tissue. Thus, glucocorticoids regulate glutamine synthetase gene expression in rat muscles at the transcriptional level via interaction with intracellular glutamine production by muscle and to mechanisms underlying glucocorticoid-induced muscle atrophy.

  5. Brainstem cholinergic modulation of muscle tone in infant rats.

    Science.gov (United States)

    Gall, Andrew J; Poremba, Amy; Blumberg, Mark S

    2007-06-01

    In week-old rats, lesions of the dorsolateral pontine tegmentum (DLPT) and nucleus pontis oralis (PnO) have opposing effects on nuchal muscle tone. Specifically, pups with DLPT lesions exhibit prolonged bouts of nuchal muscle atonia (indicative of sleep) and pups with PnO lesions exhibit prolonged bouts of high nuchal muscle tone (indicative of wakefulness). Here we test the hypothesis that nuchal muscle tone is modulated, at least in part, by cholinergically mediated interactions between these two regions. First, in unanesthetized pups, we found that chemical infusion of the cholinergic agonist carbachol (22 mm, 0.1 microL) within the DLPT produced high muscle tone. Next, chemical lesions of the PnO were used to produce a chronic state of high nuchal muscle tone, at which time the cholinergic antagonist scopolamine (10 mm, 0.1 microL) was infused into the DLPT. Scopolamine effectively decreased nuchal muscle tone, thus suggesting that lesions of the PnO increase muscle tone via cholinergic activation of the DLPT. Using 2-deoxyglucose autoradiography, metabolic activation throughout the DLPT was observed after PnO lesions. Finally, consistent with the hypothesis that PnO inactivation produces high muscle tone, infusion of the sodium channel blocker lidocaine (2%) into the PnO of unanesthetized pups produced rapid increases in muscle tone. We conclude that, even early in infancy, the DLPT is critically involved in the regulation of muscle tone and behavioral state, and that its activity is modulated by a cholinergic mechanism that is directly or indirectly controlled by the PnO.

  6. Mechanisms mediating cholinergic antral circular smooth muscle contraction in rats

    Science.gov (United States)

    Wrzos, Helena F; Tandon, Tarun; Ouyang, Ann

    2004-01-01

    AIM: To investigate the pathway (s) mediating rat antral circular smooth muscle contractile responses to the cholinomimetic agent, bethanechol and the subtypes of muscarinic receptors mediating the cholinergic contraction. METHODS: Circular smooth muscle strips from the antrum of Sprague-Dawley rats were mounted in muscle baths in Krebs buffer. Isometric tension was recorded. Cumulative concentration-response curves were obtained for (+)-cis-dioxolane (cD), a nonspecific muscarinic agonist, at 10-8-10-4 mol/L, in the presence of tetrodotoxin (TTX, 10-7 mol/L). Results were normalized to cross sectional area. A repeat concentration-response curve was obtained after incubation of the muscle for 90 min with antagonists for M1 (pirenzepine), M2 (methoctramine) and M3 (darifenacin) muscarinic receptor subtypes. The sensitivity to PTX was tested by the ip injection of 100 mg/kg of PTX 5 d before the experiment. The antral circular smooth muscles were removed from PTX-treated and non-treated rats as strips and dispersed smooth muscle cells to identify whether PTX-linked pathway mediated the contractility to bethanechol. RESULTS: A dose-dependent contractile response observed with bethanechol, was not affected by TTX. The pretreatment of rats with pertussis toxin decreased the contraction induced by bethanechol. Lack of calcium as well as the presence of the L-type calcium channel blocker, nifedipine, also inhibited the cholinergic contraction, with a reduction in response from 2.5 ± 0.4 g/mm2 to 1.2 ± 0.4 g/mm2 (P methocramine (M2) > pirenzepine (M1). CONCLUSION: The muscarinic receptors-dependent contraction of rat antral circular smooth muscles was linked to the signal transduction pathway(s) involving pertussis-toxin sensitive GTP-binding proteins and to extracellular calcium via L-type voltage gated calcium channels. The presence of the residual contractile response after the treatment with nifedipine, suggests that an additional pathway could mediate the

  7. Mechanisms mediating cholinergic antral circular smooth muscle contraction in rats

    Institute of Scientific and Technical Information of China (English)

    Helena F Wrzos; Tarun Tandon; Ann Ouyang

    2004-01-01

    AIM: To investigate the pathway (s) mediating rat antral circular smooth muscle contractile responses to the cholinomimetic agent, bethanechol and the subtypes of muscarinic receptors mediating the cholinergic contraction.METHODS: Circular smooth muscle strips from the antrum of Sprague-Dawley rats were mounted in muscle baths in Krebs buffer. Isometric tension was recorded. Cumulative concentration-response curves were obtained for (+)-cisdioxolane (cD), a nonspecific muscarinic agonist, at 10-8-10-4 mol/L, in the presence of tetrodotoxin (TTX, 10-7 mol/L).Results were normalized to cross sectional area. A repeat concentration-response curve was obtained after incubation of the muscle for 90 min with antagonists for M1 (pirenzepine),M2 (methoctramine) and M3 (darifenacin) muscarinic receptor subtypes. The sensitivity to PTX was tested by the ip injection of 100 mg/kg of PTX 5 d before the experiment. The antral circular smooth muscles were removed from PTX-treated and non-treated rats as strips and dispersed smooth muscle cells to identify whether PTX-linked pathway mediated the contractility to bethanechol.RESULTS: A dose-dependent contractile response observed with bethanechol, was not affected by TTX. The pretreatment of rats with pertussis toxin decreased the contraction induced by bethanechol. Lack of calcium as Well as the presence of the L-type calcium channel blocker, nifedipine, also inhibited the cholinergic contraction, with a reduction in response from 2.5±0.4 g/mm2 to 1.2±0.4 g/mm2 (P<0.05). The doseresponse curves were shifted to the right by muscarinic antagonists in the following order of affinity: darifenacin(M3)>methocramine (M2)>pirenzepine (M1).CONCLUSION: The muscarinic receptors-dependent contraction of rat antral circular smooth muscles was linked to the signal transduction pathway(s) involving pertussis-toxin sensitive GTP-binding proteins and to extracellular calcium via L-type voltage gated calcium channels. The presence of the

  8. Glucose uptake and transport in contracting, perfused rat muscle with different pre-contraction glycogen concentrations

    DEFF Research Database (Denmark)

    Hespel, P; Richter, Erik

    1990-01-01

    1. Glucose uptake and transport, muscle glycogen, free glucose and glucose-6-phosphate concentrations were studied in perfused resting and contracting rat skeletal muscle with different pre-contraction glycogen concentrations. Rats were pre-conditioned by a combination of swimming exercise and diet......, resulting in either low (glycogen-depleted rats), normal (control rats) or high (supercompensated rats) muscle glycogen concentrations at the time their hindlimbs were perfused. 2. Compared with control rats, pre-contraction muscle glycogen concentration was approximately 40% lower in glycogen-depleted rats......, whereas it was 40% higher in supercompensated rats. Muscle glycogen break-down correlated positively (r = 0.76; P less than 0.001) with pre-contraction muscle glycogen concentration. 3. Glucose uptake during contractions was approximately 50% higher in glycogen-depleted hindquarters than in control...

  9. Enhanced muscle glucose metabolism after exercise in the rat

    DEFF Research Database (Denmark)

    Garetto, L P; Richter, Erik; Goodman, M N

    1984-01-01

    Thirty minutes after a treadmill run, glucose utilization and glycogen synthesis in perfused rat skeletal muscle are enhanced due to an increase in insulin sensitivity (Richter et al., J. Clin. Invest. 69: 785-793, 1982). The exercise used in these studies was of moderate intensity, and muscle...... was evident. The data suggest that the restoration of muscle glycogen after exercise occurs in two phases. In phase I, muscle glycogen is depleted and insulin-stimulated glucose utilization and glucose utilization in the absence of added insulin may both be enhanced. In phase II glycogen levels have returned...... to near base-line values and only the increase in insulin sensitivity persists. It is proposed that phase I corresponds to the period of rapid glycogen repletion that immediately follows exercise and phase II to the period of supercompensation....

  10. Alterations in contractile properties of tongue muscles in old rats.

    Science.gov (United States)

    Ota, Fumikazu; Connor, Nadine P; Konopacki, Richard

    2005-10-01

    Fatigue and weakness are well-known signs of aging that are related to sarcopenia, or loss of skeletal muscle mass, organization, and strength. Sarcopenia may affect swallowing. The tongue plays a vital role in swallowing, but there is limited knowledge regarding age-related changes in lingual muscle contractile properties. Our purpose was to determine whether alterations in tongue force, temporal features of tongue muscle contraction, and fatigability are manifested as a function of aging in old rats. We evaluated tongue muscle contractile properties in young and old Fischer 344/Brown Norway rats. Contractions were elicited via bilateral electrical stimulation of the hypoglossal nerves. Maximum tongue forces and fatigability were not significantly altered in old animals, but aging was associated with significantly longer twitch contraction time and longer half-decay recovery time intervals (p < .01). The results indicated that old animals generated sufficient maximum tongue forces, but were slower in achieving these forces than young animals. These findings are consistent with reports of altered temporal parameters of tongue actions during swallowing in humans, and suggest that a disruption in the timing of muscle contraction onset and recovery may contribute to the altered tongue kinetics observed with aging.

  11. Muscle fragments on a scaffold in rats

    DEFF Research Database (Denmark)

    Jangö, Hanna; Gräs, Søren; Christensen, Lise

    2015-01-01

    INTRODUCTION AND HYPOTHESIS: The use of permanent synthetic meshes to improve the outcome of pelvic organ prolapse (POP) repair causes frequent and serious complications. The use of the synthetic, biodegradable scaffold methoxypolyethyleneglycol-polylactic-co-glycolic acid (MPEG-PLGA) seeded...... labeled with PKH26-fluorescence dye. After 8 weeks labeled cells were identified in tissue samples and histopathological and immunohistochemical analyses of connective tissue organization and desmin reactivity of muscle cells were performed. Fresh tissue samples were subjected to uniaxial biomechanical...

  12. Pioglitazone treatment restores in vivo muscle oxidative capacity in a rat model of diabetes

    NARCIS (Netherlands)

    Wessels, B.; Ciapaite, J.; van den Broek, N. M. A.; Houten, S. M.; Nicolay, K.; Prompers, J. J.

    2015-01-01

    Aim: To determine the effect of pioglitazone treatment on in vivo and ex vivo muscle mitochondrial function in a rat model of diabetes. Methods: Both the lean, healthy rats and the obese, diabetic rats are Zucker Diabetic Fatty (ZDF) rats. The homozygous fa/fa ZDF rats are obese and diabetic. The he

  13. Manual therapy ameliorates delayed-onset muscle soreness and alters muscle metabolites in rats.

    Science.gov (United States)

    Urakawa, Susumu; Takamoto, Kouichi; Nakamura, Tomoya; Sakai, Shigekazu; Matsuda, Teru; Taguchi, Toru; Mizumura, Kazue; Ono, Taketoshi; Nishijo, Hisao

    2015-02-01

    Delayed-onset muscle soreness (DOMS) can be induced by lengthening contraction (LC); it can be characterized by tenderness and movement-related pain in the exercised muscle. Manual therapy (MT), including compression of exercised muscles, is widely used as physical rehabilitation to reduce pain and promote functional recovery. Although MT is beneficial for reducing musculoskeletal pain (i.e. DOMS), the physiological mechanisms of MT remain unclear. In the present study, we first developed an animal model of MT in DOMS; LC was applied to the rat gastrocnemius muscle under anesthesia, which induced mechanical hyperalgesia 2-4 days after LC. MT (manual compression) ameliorated mechanical hyperalgesia. Then, we used capillary electrophoresis time-of-flight mass spectroscopy (CE-TOFMS) to investigate early effects of MT on the metabolite profiles of the muscle experiencing DOMS. The rats were divided into the following three groups; (1) normal controls, (2) rats with LC application (LC group), and (3) rats undergoing MT after LC (LC + MT group). According to the CE-TOFMS analysis, a total of 171 metabolites were detected among the three groups, and 19 of these metabolites were significant among the groups. Furthermore, the concentrations of eight metabolites, including branched-chain amino acids, carnitine, and malic acid, were significantly different between the LC + MT and LC groups. The results suggest that MT significantly altered metabolite profiles in DOMS. According to our findings and previous data regarding metabolites in mitochondrial metabolism, the ameliorative effects of MT might be mediated partly through alterations in metabolites associated with mitochondrial respiration.

  14. Contractions but not AICAR increase FABPpm content in rat muscle sarcolemma

    DEFF Research Database (Denmark)

    Jeppesen, Jacob; Albers, Peter; Luiken, Joost J.;

    2009-01-01

    In the present study, it was investigated whether acute muscle contractions in rat skeletal muscle increased the protein content of FABPpm in the plasma membrane. Furthermore, the effect of AICAR stimulation on FAT/CD36 and FABPpm protein content in sarcolemma of rat skeletal muscle was evaluated...

  15. Lower facial remodeling with botulinum toxin type A for the treatment of masseter hypertrophy*

    Science.gov (United States)

    Klein, Fernanda Homem de Mello de Souza; Brenner, Fabiane Mulinari; Sato, Maurício Shigeru; Robert, Fernanda Manfron Batista Rosas; Helmer, Karin Adriane

    2014-01-01

    BACKGROUND Masseter hypertrophy has been treated with botulinum toxin injections because of esthetic complaints especially in Asians. OBJECTIVES The goal of the present study was to evaluate the efficacy of abobotulin toxin use in masseter hipertrophy treatment in Brazilians. METHODS Ten Brazilian female patients with masseter hypertrophy were subjected to injections of 90U of abobotulinum toxin A applied on each side respecting the safety zone stabilished in literature and were followed up for 24 weeks. RESULTS When analyzing the coefficients between measures of middle and lower third of the face obtained from standardized photographs, an increase was observed, with statistical significance at 2 weeks (p=0.005) and 12 weeks (p=0.001). The progression of lower third reduction was 3.94%, 5.26%, 11.99%, and 5.47% (2, 4, 12, and 24 weeks respectively). All patients showed improvement in bruxism after treatment. Observed adverse effects were masticatory fatigue, smile limitation, and smile asymmetry. CONCLUSION The use of abobotulinum toxin A for masseter hypertrophy is effective in Brazilians and reached its maximum effect of facial thinning at 12 weeks. Smile limitation had a higher incidence compared to that reported in the literature and may result from risorius muscle blockage caused by toxin dissemination. Despite its side effects, 80% of the patients would like to repeat the treatment. PMID:25387491

  16. Optical characterization and composition of abdominal wall muscle from rat

    Science.gov (United States)

    Oliveira, Luís; Lage, Armindo; Pais Clemente, M.; Tuchin, Valery

    2009-06-01

    Complete optical characterization of biological tissue is desirable to develop clinical methods using optical technologies. Particularly, to develop optical clearing methods in biological tissues, it is necessary to know the composition of the tissue, the percentage of each constituent and corresponding refractive indexes. To obtain such information for rat muscle, we used a simple method to characterize tissue constituents for both content percentage and refractive index. The study consisted on measuring mass with a precision weighting scale and the refractive index with an Abbe refractometer during tissue dehydration. With the collected data, we used a theoretical model to calculate the refractive index and percentage for both interstitial fluid and solid part of the rat muscle. The results obtained are in good agreement with data published by other authors, and were considered of vital information for the optical clearing studies that we planned to perform.

  17. Muscle glucose metabolism following exercise in the rat

    DEFF Research Database (Denmark)

    Richter, Erik; Garetto, L P; Goodman, M N

    1982-01-01

    Muscle glycogen stores are depleted during exercise and are rapidly repleted during the recovery period. To investigate the mechanism for this phenomenon, untrained male rats were run for 45 min on a motor-driven treadmill and the ability of their muscles to utilize glucose was then assessed during...... perfusion of their isolated hindquarters. Glucose utilization by the hindquarter was the same in exercised and control rats perfused in the absence of added insulin; however, when insulin (30-40,000 muU/ml) was added to the perfusate, glucose utilization was greater after exercise. Prior exercise lowered...... both, the concentration of insulin that half-maximally stimulated glucose utilization (exercise, 150 muU/ml; control, 480 muU/ml) and modestly increased its maximum effect. The increase in insulin sensitivity persisted for 4 h following exercise, but was not present after 24 h. The rate-limiting step...

  18. Tissue specific phosphorylation of mitochondrial proteins isolated from rat liver, heart muscle, and skeletal muscle

    DEFF Research Database (Denmark)

    Bak, Steffen; León, Ileana R; Jensen, Ole Nørregaard;

    2013-01-01

    of TiO2 phosphopeptide-enrichment, HILIC fractionation, and LC-MS/MS on isolated mitochondria to investigate the tissue-specific mitochondrial phosphoproteomes of rat liver, heart, and skeletal muscle. In total, we identified 899 phosphorylation sites in 354 different mitochondrial proteins including......Phosphorylation of mitochondrial proteins in a variety of biological processes is increasingly being recognized and may contribute to the differences in function and energy demands observed in mitochondria from different tissues such as liver, heart, and skeletal muscle. Here, we used a combination...

  19. Distinct muscle apoptotic pathways are activated in muscles with different fiber types a rat model of critical illness myopathy

    OpenAIRE

    Barnes, Benjamin T.; Confides, Amy L.; Rich, Mark M.; Dupont-Versteegden, Esther E.

    2015-01-01

    Critical illness myopathy (CIM) is associated with severe muscle atrophy and fatigue in affected patients. Apoptotic signaling is involved in atrophy and is elevated in muscles from patients with CIM. In this study we investigated underlying mechanisms of apoptosis-related pathways in muscles with different fiber type composition in a rat model of CIM using denervation and glucocorticoid administration (denervation and steroid-induced myopathy, DSIM). Soleus and tibialis anterior (TA) muscles...

  20. UROTENSIN II RECEPTOR IN THE RAT AIRWAY SMOOTH MUSCLE AND ITS EFFECT ON THE RAT AIRWAY SMOOTH MUSCLE CELLS PROLIFERATION

    Institute of Scientific and Technical Information of China (English)

    陈亚红; 赵鸣武; 刘秀华; 姚婉贞; 杨军; 张肇康; 唐朝枢

    2001-01-01

    Objective. To investigate the characteristics of urotensin II (U-II) receptor in the rat airway smooth muscleand the effect and signal transduction pathway of U-II on the proliferation of airway smooth muscle cells.Methods. Using 125-UII binding assay to measure the Bmax and Kd of U-II receptor. Using the 3H-TdRincorporation to deter mine the effect of U-II on the proliferation of airway smooth muscle cells and its signal transduc-tion pathway. Using Fura-2/AM to measure the effect of U-II on the cytosolic free calcium concentration.Results. 1. 125I-UⅡ binding increased with the time and reached saturation at 45min. The Bmax was(ll. 36 +0.37)fmol/mg pr and Kd was (4.46 +0.61)nmol/L. 2. U-II increased 3H-TdR incorporation of theairway smooth muscle cells in a dose-dependent manner. 3. H7, PDg8059 and nicardipine, inhibitors of PKC,MAPK, calcium cha.nnel, respectively, significantly inhibited U-II-stimulated 3H-TdR incorporation of airwaysmooth muscle cells. W7, inhibitor of CaM-PK, had no effect. 4. Cyclosporin A, inhibitor of CaN, inhibited3H-TdRincorporation ofthe airway smooth muscle cells induced by U-Ⅱl in a dose-dependent manner. 5. U-Ⅱlpromot-ed cy-tosolic free calcium concentration increase by 18%.Conclusions. 1. There was U-II receptor in the rat airway smooth muscle. 2. The effect of U-II-stimulated-3H-TdR incorporation of airway smooth muscle cells was mediated by such signal transduction pathway as Ca2 +.PKC, MAPK and Ca.N, etc.``

  1. Low level laser therapy on injured rat muscle

    Science.gov (United States)

    Mantineo, M.; Pinheiro, J. P.; Morgado, A. M.

    2013-06-01

    Although studies show the clinical effectiveness of low level laser therapy (LLLT) in facilitating the muscle healing process, scientific evidence is still required to prove the effectiveness of LLLT and to clarify the cellular and molecular mechanisms triggered by irradiation. Here we evaluate the effect of different LLLT doses, using continuous illumination (830 nm), in the treatment of inflammation induced in the gastrocnemius muscle of Wistar rats, through the quantification of cytokines in systemic blood and histological analysis of muscle tissue. We verified that all applied doses produce an effect on reducing the number of inflammatory cells and the concentration of pro-inflammatory TNF-α and IL-1β cytokines. The best results were obtained for 40 mW. The results may suggest a biphasic dose response curve.

  2. Botulinum toxin injection causes hyper-reflexia and increased muscle stiffness of the triceps surae muscle in the rat.

    Science.gov (United States)

    Pingel, Jessica; Wienecke, Jacob; Lorentzen, Jakob; Nielsen, Jens Bo

    2016-12-01

    Botulinum toxin is used with the intention of diminishing spasticity and reducing the risk of development of contractures. Here, we investigated changes in muscle stiffness caused by reflex activity or elastic muscle properties following botulinum toxin injection in the triceps surae muscle in rats. Forty-four rats received injection of botulinum toxin in the left triceps surae muscle. Control measurements were performed on the noninjected contralateral side in all rats. Acute experiments were performed, 1, 2, 4, and 8 wk following injection. The triceps surae muscle was dissected free, and the Achilles tendon was cut and attached to a muscle puller. The resistance of the muscle to stretches of different amplitudes and velocities was systematically investigated. Reflex-mediated torque was normalized to the maximal muscle force evoked by supramaximal stimulation of the tibial nerve. Botulinum toxin injection caused severe atrophy of the triceps surae muscle at all time points. The force generated by stretch reflex activity was also strongly diminished but not to the same extent as the maximal muscle force at 2 and 4 wk, signifying a relative reflex hyperexcitability. Passive muscle stiffness was unaltered at 1 wk but increased at 2, 4, and 8 wk (P botulinum toxin causes a relative increase in reflex stiffness, which is likely caused by compensatory neuroplastic changes. The stiffness of elastic elements in the muscles also increased. The data are not consistent with the ideas that botulinum toxin is an efficient antispastic medication or that it may prevent development of contractures.

  3. Procedures for rat in situ skeletal muscle contractile properties.

    Science.gov (United States)

    MacIntosh, Brian R; Esau, Shane P; Holash, R John; Fletcher, Jared R

    2011-10-15

    There are many circumstances where it is desirable to obtain the contractile response of skeletal muscle under physiological circumstances: normal circulation, intact whole muscle, at body temperature. This includes the study of contractile responses like posttetanic potentiation, staircase and fatigue. Furthermore, the consequences of disease, disuse, injury, training and drug treatment can be of interest. This video demonstrates appropriate procedures to set up and use this valuable muscle preparation. To set up this preparation, the animal must be anesthetized, and the medial gastrocnemius muscle is surgically isolated, with the origin intact. Care must be taken to maintain the blood and nerve supplies. A long section of the sciatic nerve is cleared of connective tissue, and severed proximally. All branches of the distal stump that do not innervate the medial gastrocnemius muscle are severed. The distal nerve stump is inserted into a cuff lined with stainless steel stimulating wires. The calcaneus is severed, leaving a small piece of bone still attached to the Achilles tendon. Sonometric crystals and/or electrodes for electromyography can be inserted. Immobilization by metal probes in the femur and tibia prevents movement of the muscle origin. The Achilles tendon is attached to the force transducer and the loosened skin is pulled up at the sides to form a container that is filled with warmed paraffin oil. The oil distributes heat evenly and minimizes evaporative heat loss. A heat lamp is directed on the muscle, and the muscle and rat are allowed to warm up to 37°C. While it is warming, maximal voltage and optimal length can be determined. These are important initial conditions for any experiment on intact whole muscle. The experiment may include determination of standard contractile properties, like the force-frequency relationship, force-length relationship, and force-velocity relationship. With care in surgical isolation, immobilization of the origin of the

  4. Quercetin protects rat skeletal muscle from ischemia reperfusion injury.

    Science.gov (United States)

    Ekinci Akdemir, Fazile Nur; Gülçin, İlhami; Karagöz, Berna; Soslu, Recep

    2016-01-01

    In this study, we investigated the potential beneficial effects of quercetin on skeletal muscle ischemia reperfusion injury. Twenty-four Sprague-Dawley type rats were randomly divided into four groups. In the sham group, only gastrocnemius muscle were removed and given no quercetin. In ischemia group, all the femoral artery, vein and collaterals were occluded in the left hindlimb by applying tourniquate under general anaesthesia for three hours but reperfusion was not done. In the Quercetin + Ischemia reperfusion group, quercetin (200 mg kg(-1) dose orally) was given during one-week reoperation and later ischemia reperfusion model was done. Finally, gastrocnemius muscle samples were removed to measure biochemical parameters. The biomarkers, MDA levels, SOD, CAT and GPx activities, were evaluated related to skeletal muscle ischemia reperfusion injury. MDA levels reduced and SOD, CAT and GPx activities increased significantly in Quercetin + Ischemia reperfusion group. Results clearly showed that Quercetin have a protective role against oxidative damage induced by ischemia reperfusion in rats.

  5. Basal and insulin-stimulated skeletal muscle sugar transport in endotoxic and bacteremic rats

    Energy Technology Data Exchange (ETDEWEB)

    Westfall, M.V.; Sayeed, M.M.

    1988-04-01

    Membrane glucose transport with and without insulin was studied in soleus muscle from 5-h endotoxic rats (40 mg/kg Salmonella enteritidis lipopolysaccharide), and in soleus and epitrochlearis muscles from 12-h bacteremic (Escherichia coli, 4 X 10(10) CFU/kg) rats. Glucose transport was measured in muscles by evaluating the fractional efflux of /sup 14/C-labeled 3-O-methylglucose (/sup 14/C-3-MG) after loading muscles with /sup 14/C-3-MG. Basal 3-MG transport was elevated in soleus muscles from endotoxic as well as in soleus and epitrochlearis muscles from bacteremic rats compared with time-matched controls. Low insulin concentrations stimulated /sup 14/C-3-MG transport more in bacteremic and endotoxic rat muscles than in controls. However, sugar transport in the presence of high insulin dose was attenuated in soleus and epitrochlearis muscles from bacteremic rats and soleus muscles from endotoxic rats compared with controls. Analysis of the dose-response relationship with ALLFIT revealed that the maximal transport response to insulin was significantly decreased in both models of septic shock. Sensitivity to insulin (EC50) was increased in endotoxic rat muscles, and a somewhat similar tendency was observed in bacteremic rat soleus muscles. Neural and humoral influences and/or changes in cellular metabolic energy may contribute to the increase in basal transport. Shifts in insulin-mediated transport may be due to alterations in insulin-receptor-effector coupling and/or the number of available glucose transporters.

  6. Implantation of muscle satellite cells overexpressing myogenin improves denervated muscle atrophy in rats

    Directory of Open Access Journals (Sweden)

    H. Shen

    2016-01-01

    Full Text Available This study evaluated the effect of muscle satellite cells (MSCs overexpressing myogenin (MyoG on denervated muscle atrophy. Rat MSCs were isolated and transfected with the MyoG-EGFP plasmid vector GV143. MyoG-transfected MSCs (MTMs were transplanted into rat gastrocnemius muscles at 1 week after surgical denervation. Controls included injections of untransfected MSCs or the vehicle only. Muscles were harvested and analyzed at 2, 4, and 24 weeks post-transplantation. Immunofluorescence confirmed MyoG overexpression in MTMs. The muscle wet weight ratio was significantly reduced at 2 weeks after MTM injection (67.17±6.79 compared with muscles injected with MSCs (58.83±5.31 or the vehicle (53.00±7.67; t=2.37, P=0.04 and t=3.39, P=0.007, respectively. The muscle fiber cross-sectional area was also larger at 2 weeks after MTM injection (2.63×103±0.39×103 compared with MSC injection (1.99×103±0.58×103 or the vehicle only (1.57×103±0.47×103; t=2.24, P=0.049 and t=4.22, P=0.002, respectively. At 4 and 24 weeks post-injection, the muscle mass and fiber cross-sectional area were similar across all three experimental groups. Immunohistochemistry showed that the MTM group had larger MyoG-positive fibers. The MTM group (3.18±1.13 also had higher expression of MyoG mRNA than other groups (1.41±0.65 and 1.03±0.19 at 2 weeks after injection (t=2.72, P=0.04. Transplanted MTMs delayed short-term atrophy of denervated muscles. This approach can be optimized as a novel stand-alone therapy or as a bridge to surgical re-innervation of damaged muscles.

  7. Implantation of muscle satellite cells overexpressing myogenin improves denervated muscle atrophy in rats.

    Science.gov (United States)

    Shen, H; Lv, Y; Shen, X Q; Xu, J H; Lu, H; Fu, L C; Duan, T

    2016-02-01

    This study evaluated the effect of muscle satellite cells (MSCs) overexpressing myogenin (MyoG) on denervated muscle atrophy. Rat MSCs were isolated and transfected with the MyoG-EGFP plasmid vector GV143. MyoG-transfected MSCs (MTMs) were transplanted into rat gastrocnemius muscles at 1 week after surgical denervation. Controls included injections of untransfected MSCs or the vehicle only. Muscles were harvested and analyzed at 2, 4, and 24 weeks post-transplantation. Immunofluorescence confirmed MyoG overexpression in MTMs. The muscle wet weight ratio was significantly reduced at 2 weeks after MTM injection (67.17±6.79) compared with muscles injected with MSCs (58.83±5.31) or the vehicle (53.00±7.67; t=2.37, P=0.04 and t=3.39, P=0.007, respectively). The muscle fiber cross-sectional area was also larger at 2 weeks after MTM injection (2.63×10³±0.39×10³) compared with MSC injection (1.99×10³±0.58×10³) or the vehicle only (1.57×10³±0.47×10³; t=2.24, P=0.049 and t=4.22, P=0.002, respectively). At 4 and 24 weeks post-injection, the muscle mass and fiber cross-sectional area were similar across all three experimental groups. Immunohistochemistry showed that the MTM group had larger MyoG-positive fibers. The MTM group (3.18±1.13) also had higher expression of MyoG mRNA than other groups (1.41±0.65 and 1.03±0.19) at 2 weeks after injection (t=2.72, P=0.04). Transplanted MTMs delayed short-term atrophy of denervated muscles. This approach can be optimized as a novel stand-alone therapy or as a bridge to surgical re-innervation of damaged muscles.

  8. Histochemical and morphological characteristics of the levator ani muscle in rats

    OpenAIRE

    2011-01-01

    The current study aimed to analyze the histochemical and morphological characteristics of the levator ani muscle in rats. For this, we used 10 Wistar rats (5 males and 5 females), weighing between 200 and 765g. The animals were dissected fresh and in formalin for the levator ani muscle anatomical observation. Muscle fragments were collected and frozen in n-Hexane previously cooled in liquid nitrogen. Then, the muscles were transferred to a microtome cryostat (HM 505 E Microm), being fixed in ...

  9. AN ELECTROMYOGRAPHIC STUDY OF WHETHER THE DIGASTRIC MUSCLES ARE CONTROLLED BY JAW-CLOSING PROPRIOCEPTORS IN MAN

    NARCIS (Netherlands)

    VANWILLIGEN, JD; MORIMOTO, T; BROEKHUIJSEN, ML; BIJL, GK; INOUE, T

    1993-01-01

    Whether in the oral system the digastric muscles (which lack muscle spindles) are under the control of proprioceptive information from the masseter muscles (which contain muscle spindles) was investigated by analysing whether and how the masseters and digastrics showed coordinated behaviour during a

  10. Muscle specific changes in length-force characteristics of the calf muscles in the spastic Han-Wistar rat

    DEFF Research Database (Denmark)

    Olesen, Annesofie Thorup; Jensen, Bente Rona; Uhlendorf, Toni L;

    2014-01-01

    , the extent of this interaction was not different in the spastic rats. In conclusion, the effects of spasticity on length-force characteristics were muscle specific. The changes seen for GA and PL muscles are consistent with the changes in limb mechanics reported for human patients. Our results indicate......The purpose of the present study was to investigate muscle mechanical properties and mechanical interaction between muscles in the lower hindlimb of the spastic mutant rat. Length-force characteristics of gastrocnemius (GA), soleus (SO) and plantaris (PL) were assessed in anesthetized spastic...... and normally-developed Han-Wistar rats. In addition, the extent of epimuscular myofascial force transmission between synergistic GA, SO and PL, as well as between the calf muscles and antagonistic tibialis anterior (TA) was investigated. Active length-force characteristics of spastic GA and PL were narrower...

  11. Effects of acidification and increased extracellular potassium on dynamic muscle contractions in isolated rat muscles.

    Science.gov (United States)

    Overgaard, Kristian; Højfeldt, Grith Westergaard; Nielsen, Ole Bækgaard

    2010-12-15

    Since accumulation of both H(+) and extracellular K(+) have been implicated in the reduction in dynamic contractile function during intense exercise, we investigated the effects of acidification and high K(+) on muscle power and the force-velocity relation in non-fatigued rat soleus muscles. Contractions were elicited by supramaximal electrical stimulation at 60 Hz. Force-velocity (FV) curves were obtained by fitting data on force and shortening velocity at different loads to the Hill equation. Acidification of the muscles by incubation with up to 24 mm lactic acid produced no significant changes in maximal power (P(max)) at 30 °C. More pronounced acidification, obtained by increasing CO(2) levels in the equilibration gas from 5% to 53%, markedly decreased P(max) and maximal isometric force (F(max)), increased the curvature of the FV relation, but left maximal shortening velocity (V(max)) unchanged. Increase of extracellular K(+) from 4 to 10 mm caused a depression of 58% in P(max) and 52% in F(max), but had no significant effect on V(max) or curvature of the FV curve. When muscles at 10 mM K(+) were acidified by 20 mm lactic acid, P(max) and F(max) recovered completely to the initial control level at 4 mm K(+). CO(2) acidification also induced significant recovery of dynamic contractions, but not entirely to control levels. These results demonstrate that in non-fatigued muscles severe acidification can be detrimental to dynamic contractile function, but in muscles depolarised by exposure to high extracellular [K(+)], approaching the [K(+)] level seen during intense fatiguing exercise, acidification can have positive protective effects on dynamic muscle function.

  12. INFLUENCE OF SHORTENED AND LENGTHENED IMMOBILIZATION ON RAT SOLEUS MUSCLE ATROPHY

    Institute of Scientific and Technical Information of China (English)

    邢国刚; 樊小力; 吴苏娣; 宋新爱; 朱保恭; 唐斌

    2001-01-01

    Objective: To study the possible mechanism and prevention of disuse muscle atrophy. Methods: The shortened immobilization (plaster fixation) of rat' s soleus muscle (SOL) was used as the model of muscle and the lengthened immobilization of rat' s SOL muscle as "passive stretch" method. Types of skeletal muscle fibers were differentiated with m - ATPase staining technique. The changes of rat' s SOL muscle weight (wet weight) as well as the types and the mean cross - sectional area (CSA) of muscle fibers were examined respectively on day 2, 4,7, 14 and 21 under both shortened and lengthened immobilization and then the effect of passive stretch on soleus muscle atrophy in immobilized rats was observed. Results: When shortened immobilization was applied for 4 days, SOL muscle weight (wet weight) became lighter; the fiber crosssectional area (CSA) shrank and type Ⅰ muscle fibers started transforming into type Ⅱ, which all indicated immobilized muscles began to atrophy and as immobilization proceeded, muscle atrophy proceeded toward higher level. In contrast to that, when lengthened immobilization was applied, SOL muscle didn' t show any sign of atrophy until 7th day, and reached its highest level on day 14 and maintained that level even though immobilization continued. Conclusion: From the results, we conclude that passive stretch can either relieve or defer disuse muscle atrophy.

  13. Effects of interocclusal distance on bite force and masseter EMG in healthy participants.

    Science.gov (United States)

    Arima, T; Takeuchi, T; Honda, K; Tomonaga, A; Tanosoto, T; Ohata, N; Svensson, P

    2013-12-01

    The aim of this study was to investigate effects of interocclusal distance (IOD) on bite force and masseter electromyographic (EMG) activity during different isometric contraction tasks. Thirty-one healthy participants (14 women and 17 men, 21·2 ± 1·8 years) were recruited. Maximal Voluntary Occlusal Bite Force (MVOBF) between the first molars and masseter EMG activity during all the isometric-biting tasks were measured. The participants were asked to bite at submaximal levels of 20%, 40%, 60% and 80% MVOBF with the use of visual feedback. The thickness of the force transducer was set at 8, 12, 16 and 20 mm (= IOD), and sides were tested in random sequence. MVOBF was significantly higher at 8 mm compared with all other IODs (P EMG (P EMG activity compared with the balancing side (P EMG at any IODs. The results replicated the finding that higher occlusal forces can be generated between the first molars at shorter IODs. The new finding in this study was that an effect of hand dominance could be found on masseter muscle activity during isometric biting. This may suggest that there can be a general dominant side effect on human jaw muscles possibly reflecting differences in motor unit recruitment strategies.

  14. Injection of adjuvant but not acidic saline into craniofacial muscle evokes nociceptive behaviors and neuropeptide expression.

    Science.gov (United States)

    Ambalavanar, R; Yallampalli, C; Yallampalli, U; Dessem, D

    2007-11-09

    Craniofacial muscle pain including muscular temporomandibular disorders accounts for a substantial portion of all pain perceived in the head and neck region. In spite of its high clinical prevalence, the mechanisms of chronic craniofacial muscle pain are not well understood. Injection of acidic saline into rodent hindlimb muscles produces pathologies which resemble muscular pathologies in chronic pain patients. Here we investigated whether analogous transformations occur following repeated injections of acidic saline into the rat masseter muscle. Injection of acidic saline (pH 4) into the masseter muscle transiently lowered i.m. pH to levels comparable to those reported for rodent hindlimb muscles. Nevertheless, repeated unilateral or bilateral injections of acidic saline (pH 4) into the masseter muscle failed to alter nociceptive behavioral responses as occurs in the hindlimb. Changing the pH of injected saline to pH 3.0 or 5.0 also did not evoke nocifensive behavior. Acid sensing ion channel 3 receptors, which are implicated in transformations following acidification of hindlimb muscles, were found on trigeminal ganglion muscle afferent neurons via combined neuronal tracing and immunocytochemistry. In contrast to the acidic saline, injection of complete Freund's adjuvant (CFA) into the masseter muscle induced mechanical allodynia for 3 weeks, thermal hyperalgesia for 1 week and an increase in the number of calcitonin gene-related peptide (CGRP)-immunoreactive muscle afferent neurons in the trigeminal ganglion. Although pH may alter CGRP release in primary afferent neurons, the number of CGRP-muscle afferent neurons did not change following i.m. injection of acidic saline. Further, there was no change in ganglionic iCGRP levels at 1, 4 or 12 days after i.m. injection of acidic saline. While these findings extend our earlier reports that CFA-induced muscle inflammation results in behavioral and neuropeptide changes they further suggest that i.m. acidification in

  15. Differences in Age-Related Alterations in Muscle Contraction Properties in Rat Tongue and Hindlimb

    Science.gov (United States)

    Connor, Nadine P.; Ota, Fumikazu; Nagai, Hiromi; Russell, John A.; Leverson, Glen

    2008-01-01

    Purpose: Because of differences in muscle architecture and biomechanics, the purpose of this study was to determine whether muscle contractile properties of rat hindlimb and tongue were differentially affected by aging. Method: Deep peroneal and hypoglossal nerves were stimulated in 6 young and 7 old Fischer 344-Brown Norway rats to allow…

  16. Differences in Age-Related Alterations in Muscle Contraction Properties in Rat Tongue and Hindlimb

    Science.gov (United States)

    Connor, Nadine P.; Ota, Fumikazu; Nagai, Hiromi; Russell, John A.; Leverson, Glen

    2008-01-01

    Purpose: Because of differences in muscle architecture and biomechanics, the purpose of this study was to determine whether muscle contractile properties of rat hindlimb and tongue were differentially affected by aging. Method: Deep peroneal and hypoglossal nerves were stimulated in 6 young and 7 old Fischer 344-Brown Norway rats to allow…

  17. Electrical stimulation using sine waveform prevents unloading-induced muscle atrophy in the deep calf muscles of rat.

    Science.gov (United States)

    Tanaka, Minoru; Hirayama, Yusuke; Fujita, Naoto; Fujino, Hidemi

    2014-09-01

    The aim of this study was to compare the effects of electrical stimulation by using rectangular and sine waveforms in the prevention of deep muscle atrophy in rat calf muscles. Rats were randomly divided into the following groups: control, hindlimb unloading (HU), and HU plus electrical stimulation (ES). The animals in the ES group were electrically stimulated using rectangular waveform (RS) on the left calves and sine waveform (SS) on the right calves, twice a day, for 2 weeks during unloading. HU for 2 weeks resulted in a loss of the muscle mass, a decrease in the cross-sectional area of the muscle fibers, and overexpression of ubiquitinated proteins in the gastrocnemius and soleus muscles. In contrast, electrical stimulation with RS attenuated the HU-induced reduction in the cross-sectional area of muscle fibers and the increase of ubiquitinated proteins in the gastrocnemius muscle. However, electrical stimulation with RS failed to prevent muscle atrophy in the deep portion of the gastrocnemius and the soleus muscles. Nevertheless, electrical stimulation with SS attenuated the HU-induced muscle atrophy and the up-regulation of ubiquitinated proteins in both gastrocnemius and soleus muscles. This indicates that SS was more effective in the prevention of deep muscle atrophy than RS. Since the skin muscle layers act like the plates of a capacitor, separated by the subcutaneous adipose layer, the SS can pass through this capacitor more easily than the RS. Hence, SS can prevent the progressive loss of muscle fibers in the deep portion of the calf muscles. Copyright © 2014 Elsevier GmbH. All rights reserved.

  18. Preservation of rat skeletal muscle energy metabolism by illumination.

    Science.gov (United States)

    Lindgård, Ann; Lundberg, Jonas; Rakotonirainy, Olivier; Elander, Anna; Soussi, Bassam

    2003-04-25

    Skeletal muscle viability is crucially dependent on the tissue levels of its high energy phosphates. In this study we investigated the effect of the preservation medium Perfadex and illumination with Singlet Oxygen Energy (SOE). Singlet oxygen can be produced photochemically by energy transfer from an excited photosensitizer. The energy emitted from singlet oxygen upon relaxation to its triplet state is captured as photons at 634 nm and is here referred to as SOE. Rat hind limb rectus femoris muscles were preserved for five hours at 22 degrees C in Perfadex, saline, SOE illuminated Perfadex or SOE illuminated saline. Extracts of the muscles were analysed by 31P NMR. Data were analysed using two-way analysis of variance and are given as mean values micromol/g dry weight) +/- SEM. The ATP concentration was higher (p = 0.006) in saline groups (4.52) compared with Perfadex groups (2.82). There was no statistically significant difference in PCr between the saline groups (1.25) and Perfadex groups (0.82). However, there were higher (p = 0.003) ATP in the SOE illuminated groups (4.61) compared with the non-illuminated groups (2.73). The PCr was also higher (p < 0.0001) in the SOE illuminated groups (1.89) compared with the non-illuminated groups (0.18). In conclusion, Perfadex in this experimental model was incapable of preserving the high energy phosphates in skeletal muscle during 5 hours of ischemia. Illumination with SOE at 634 nm improved the preservation potential, in terms of a positive effect on the energy status of the muscle cell.

  19. Oxygen exchange profile in rat muscles of contrasting fibre types

    Science.gov (United States)

    Behnke, Brad J; McDonough, Paul; Padilla, Danielle J; Musch, Timothy I; Poole, David C

    2003-01-01

    To determine whether fibre type affects the O2 exchange characteristics of skeletal muscle at the microcirculatory level we tested the hypothesis that, following the onset of contractions, muscle comprising predominately type I fibres (soleus, Sol, 86 % type I) would, based on demonstrated blood flow responses, exhibit a blunted microvascular PO2 (PO2,m, which is determined by the O2 delivery () to O2 uptake () ratio) profile (assessed via phosphorescence quenching) compared to muscle of primarily type II fibres (peroneal, Per, 84 % type II). PO2,m was measured at rest, and following the rest-contractions (twitch, 1 Hz, 2–4 V for 120 s) transition in Sol (n = 6) and Per (n = 6) muscles of Sprague-Dawley rats. Both muscles exhibited a delay followed by a mono-exponential decrease in PO2,m to the steady state. However, compared with Sol, Per demonstrated (1) a larger change in baseline minus steady state contracting PO2,m (ΔPO2,m) (Per, 13.4 ± 1.7 mmHg; Sol, 8.6 ± 0.9 mmHg, P < 0.05); (2) a faster mean response time (i.e. time delay (TD) plus time constant (τ); Per, 23.8 ± 1.5 s; Sol, 39.6 ± 4.3 s, P < 0.05); and therefore (3) a greater rate of PO2,m decline (ΔPO2,m/τ; Per, 0.92 ± 0.08 mmHg s−1; Sol, 0.42 ± 0.05 mmHg s−1, P < 0.05). These data demonstrate an increased microvascular pressure head of O2 at any given point after the initial time delay for Sol versus Per following the onset of contractions that is probably due to faster dynamics relative to those of . PMID:12692174

  20. Green tea extract attenuates muscle loss and improves muscle function during disuse, but fails to improve muscle recovery following unloading in aged rats

    Science.gov (United States)

    Bennett, Brian T.; Wilson, Joseph C.; Sperringer, Justin; Mohamed, Junaith S.; Edens, Neile K.; Pereira, Suzette L.

    2014-01-01

    In this study we tested the hypothesis that green tea extract (GTE) would improve muscle recovery after reloading following disuse. Aged (32 mo) Fischer 344 Brown Norway rats were randomly assigned to receive either 14 days of hindlimb suspension (HLS) or 14 days of HLS followed by normal ambulatory function for 14 days (recovery). Additional animals served as cage controls. The rats were given GTE (50 mg/kg body wt) or water (vehicle) by gavage 7 days before and throughout the experimental periods. Compared with vehicle treatment, GTE significantly attenuated the loss of hindlimb plantaris muscle mass (−24.8% vs. −10.7%, P muscle function or mass compared with vehicle treatment, animals given green tea via gavage maintained the lower losses of muscle mass that were found during HLS (−25.2% vs. −16.0%, P muscle fiber cross-sectional area loss in both plantaris (−39.9% vs. −23.9%, P muscles after HLS. This green tea-induced difference was not transient but was maintained over the reloading period for plantaris (−45.6% vs. −21.5%, P muscle fiber cross-sectional area (−38.7% vs. −10.9%, P muscles during recovery from HLS compared with vehicle-treated muscles and decreased oxidative stress and abundance of the Bcl-2-associated X protein (Bax), yet this did not further improve muscle recovery in reloaded muscles. These data suggest that muscle recovery following disuse in aging is complex. Although satellite cell proliferation and differentiation are critical for muscle repair to occur, green tea-induced changes in satellite cell number is by itself insufficient to improve muscle recovery following a period of atrophy in old rats. PMID:25414242

  1. [Amino acid composition of the rat quadriceps femoris muscle after a flight on the Kosmos-936 biosatellite].

    Science.gov (United States)

    Vlasova, T F; Miroshnikova, E B; Poliakov, V V; Murugova, T P

    1982-01-01

    The amino acid composition of the quadriceps muscle of rats flown onboard the biosatellite Cosmos-936 and exposed to the ground-based synchronous control experiment was studied. The weightless rats showed changes in the amino acid concentration in the quadriceps muscle. The centrifuged flight and synchronous rats displayed an accumulation of free amino acids in the above muscle.

  2. Transcutaneous carbon dioxide application accelerates muscle injury repair in rat models.

    Science.gov (United States)

    Akahane, Shiho; Sakai, Yoshitada; Ueha, Takeshi; Nishimoto, Hanako; Inoue, Miho; Niikura, Takahiro; Kuroda, Ryosuke

    2017-05-01

    Skeletal muscle injuries are commonly observed in sports and traumatology medicine. Previously, we demonstrated that transcutaneous application of carbon dioxide (CO2) to lower limbs increased the number of muscle mitochondria and promoted muscle endurance. Therefore, we aimed to investigate whether transcutaneous CO2 application could enhance recovery from muscle injury. Tibialis anterior muscle damage was induced in 27 Sprague Dawley rats via intramuscular injection of bupivacaine. After muscle injury, rats were randomly assigned to transcutaneous CO2-treated or -untreated groups. From each group, three rats were sacrificed at weeks one, two, four and six. At each time point, histology and immunofluorescence analyses were performed, and changes in muscle weight, muscle weight/body weight ratio, muscle fibre circumference, gene expression levels and capillary density were measured. Injured muscle fibres were completely repaired at week six in the CO2-treated group but only partially repaired in the untreated group. The repair of basement and plasma membranes did not differ significantly between groups. However, expression levels of genes and proteins related to muscle protein synthesis were significantly higher in the CO2-treated group and significantly more capillaries four weeks after injury. Transcutaneous CO2 application can accelerate recovery after muscle injury in rats.

  3. Alterations in Skeletal Muscle Microcirculation of Head-Down Tilted Rats

    Science.gov (United States)

    Musacchia, X. J.; Stepke, Bernhard; Fleming, John T.; Joshua, Irving G.

    1992-01-01

    In this study we assessed the function of microscopic blood vessels in skeletal muscle (cremaster muscle) for alterations which may contribute to the observed elevation of blood pressure associated with head-down tilted whole body suspension (HDT/WBS), a model of weightlessness. Arteriolar baseline diameters, vasoconstrictor responses to norepinephrine (NE) and vasodilation to nitroprusside (NP) were assessed in control rats, rats suspended for 7 or 14 day HDT/WBS rats, and rats allowed to recover for 1 day after 7 days HDT/WBS. Neither baseline diameters nor ability to dilate were influenced by HDT/WBS. Maximum vasoconstriction to norepinephrine was significantly greater in arterioles of hypertensive 14 day HDT/WBS rats. This first study of the intact microvasculature in skeletal muscle indicates that an elevated contractility of arterioles to norepinephrine in suspended rats, and suggests an elevated peripheral resistance in striated muscle may contribute to the increase in blood pressures among animals subjected to HDT/WBS.

  4. Functional Effects of Hyperthyroidism on Cardiac Papillary Muscle in Rats

    Science.gov (United States)

    Vieira, Fabricio Furtado; Olivoto, Robson Ruiz; da Silva, Priscyla Oliveira; Francisco, Julio Cesar; Fogaça, Rosalvo Tadeu Hochmuller

    2016-01-01

    Background Hyperthyroidism is currently recognized to affect the cardiovascular system, leading to a series of molecular and functional changes. However, little is known about the functional influence of hyperthyroidism in the regulation of cytoplasmic calcium and on the sodium/calcium exchanger (NCX) in the cardiac muscle. Objectives To evaluate the functional changes in papillary muscles isolated from animals with induced hyperthyroidism. Methods We divided 36 Wistar rats into a group of controls and another of animals with hyperthyroidism induced by intraperitoneal T3 injection. We measured in the animals' papillary muscles the maximum contraction force, speed of contraction (+df/dt) and relaxation (-df/dt), contraction and relaxation time, contraction force at different concentrations of extracellular sodium, post-rest potentiation (PRP), and contraction force induced by caffeine. Results In hyperthyroid animals, we observed decreased PRP at all rest times (p < 0.05), increased +df/dt and -df/dt (p < 0.001), low positive inotropic response to decreased concentration of extracellular sodium (p < 0.001), reduction of the maximum force in caffeine-induced contraction (p < 0.003), and decreased total contraction time (p < 0.001). The maximal contraction force did not differ significantly between groups (p = 0.973). Conclusion We hypothesize that the changes observed are likely due to a decrease in calcium content in the sarcoplasmic reticulum, caused by calcium leakage, decreased expression of NCX, and increased expression of a-MHC and SERCA2.

  5. Functional Effects of Hyperthyroidism on Cardiac Papillary Muscle in Rats

    Directory of Open Access Journals (Sweden)

    Fabricio Furtado Vieira

    Full Text Available Abstract Background: Hyperthyroidism is currently recognized to affect the cardiovascular system, leading to a series of molecular and functional changes. However, little is known about the functional influence of hyperthyroidism in the regulation of cytoplasmic calcium and on the sodium/calcium exchanger (NCX in the cardiac muscle. Objectives: To evaluate the functional changes in papillary muscles isolated from animals with induced hyperthyroidism. Methods: We divided 36 Wistar rats into a group of controls and another of animals with hyperthyroidism induced by intraperitoneal T3 injection. We measured in the animals' papillary muscles the maximum contraction force, speed of contraction (+df/dt and relaxation (-df/dt, contraction and relaxation time, contraction force at different concentrations of extracellular sodium, post-rest potentiation (PRP, and contraction force induced by caffeine. Results: In hyperthyroid animals, we observed decreased PRP at all rest times (p < 0.05, increased +df/dt and -df/dt (p < 0.001, low positive inotropic response to decreased concentration of extracellular sodium (p < 0.001, reduction of the maximum force in caffeine-induced contraction (p < 0.003, and decreased total contraction time (p < 0.001. The maximal contraction force did not differ significantly between groups (p = 0.973. Conclusion: We hypothesize that the changes observed are likely due to a decrease in calcium content in the sarcoplasmic reticulum, caused by calcium leakage, decreased expression of NCX, and increased expression of a-MHC and SERCA2.

  6. Effects of voluntary wheel running on satellite cells in the rat plantaris muscle

    OpenAIRE

    Atsushi Kojima; Mitsutoshi Kurosaka; Yuji Ogura; Hisashi Naito; Shizuo Katamoto; Katsumasa Goto

    2009-01-01

    This study investigated the effects of voluntary wheel running on satellite cells in the rat plantaris muscle. Seventeen 5-week-old male Wistar rats were assigned to a control (n = 5) or training (n = 12) group. Each rat in the training group ran voluntarily in a running-wheel cage for 8 weeks. After the training period, the animals were anesthetized, and the plantaris muscles were removed, weighed, and analyzed immunohistochemically and biochemically. Although there were no significant diffe...

  7. Effect of one stretch a week applied to the immobilized soleus muscle on rat muscle fiber morphology

    Directory of Open Access Journals (Sweden)

    Gomes A.R.S.

    2004-01-01

    Full Text Available We determined the effect of stretching applied once a week to the soleus muscle immobilized in the shortened position on muscle fiber morphology. Twenty-six male Wistar rats weighing 269 ± 26 g were divided into three groups. Group I, the left soleus was immobilized in the shortened position for 3 weeks; group II, the soleus was immobilized in the shortened position and stretched once a week for 3 weeks; group III, the soleus was submitted only to stretching once a week for 3 weeks. The medial part of the soleus muscle was frozen for histology and muscle fiber area evaluation and the lateral part was used for the determination of number and length of serial sarcomeres. Soleus muscle submitted only to immobilization showed a reduction in weight (44 ± 6%, P = 0.002, in serial sarcomere number (23 ± 15% and in cross-sectional area of the fibers (37 ± 31%, P < 0.001 compared to the contralateral muscles. The muscle that was immobilized and stretched showed less muscle fiber atrophy than the muscles only immobilized (P < 0.05. Surprisingly, in the muscles submitted only to stretching, fiber area was decreased compared to the contralateral muscle (2548 ± 659 vs 2961 ± 806 µm², respectively, P < 0.05. In conclusion, stretching applied once a week for 40 min to the soleus muscle immobilized in the shortened position was not sufficient to prevent the reduction of muscle weight and of serial sarcomere number, but provided significant protection against muscle fiber atrophy. In contrast, stretching normal muscles once a week caused a reduction in muscle fiber area.

  8. Leucine-enriched essential amino acids attenuate inflammation in rat muscle and enhance muscle repair after eccentric contraction.

    Science.gov (United States)

    Kato, Hiroyuki; Miura, Kyoko; Nakano, Sayako; Suzuki, Katsuya; Bannai, Makoto; Inoue, Yoshiko

    2016-09-01

    Eccentric exercise results in prolonged muscle damage that may lead to muscle dysfunction. Although inflammation is essential to recover from muscle damage, excessive inflammation may also induce secondary damage, and should thus be suppressed. In this study, we investigated the effect of leucine-enriched essential amino acids on muscle inflammation and recovery after eccentric contraction. These amino acids are known to stimulate muscle protein synthesis via mammalian target of rapamycin (mTOR), which, is also considered to alleviate inflammation. Five sets of 10 eccentric contractions were induced by electrical stimulation in the tibialis anterior muscle of male SpragueDawley rats (8-9 weeks old) under anesthesia. Animals received a 1 g/kg dose of a mixture containing 40 % leucine and 60 % other essential amino acids or distilled water once a day throughout the experiment. Muscle dysfunction was assessed based on isometric dorsiflexion torque, while inflammation was evaluated by histochemistry. Gene expression of inflammatory cytokines and myogenic regulatory factors was also measured. We found that leucine-enriched essential amino acids restored full muscle function within 14 days, at which point rats treated with distilled water had not fully recovered. Indeed, muscle function was stronger 3 days after eccentric contraction in rats treated with amino acids than in those treated with distilled water. The amino acid mix also alleviated expression of interleukin-6 and impeded infiltration of inflammatory cells into muscle, but did not suppress expression of myogenic regulatory factors. These results suggest that leucine-enriched amino acids accelerate recovery from muscle damage by preventing excessive inflammation.

  9. EFFECTS OF PASSIVE STRETCH ON SOLEUS MUSCLE ATROPHY IN IMMOBILIZED RATS

    Institute of Scientific and Technical Information of China (English)

    邢国刚; 樊小力; 吴苏娣; 宋新爱; 朱保恭; 唐斌

    2002-01-01

    Objective To study the possible mechanism and prevention of disused muscle atrophy. Methods The shortened immobilization (plaster fixation) of rat's soleus muscle(SOL) was used as the model of muscle "disuse" and the lengthened immobilization of rat's SOL muscle as "passive stretch" method. Types of skeletal muscle fibers were differentiated with m-ATPase staining technique. The changes of rat's SOL weight (wet weight) as well as the types and the mean cross sectional area (CSA) of muscle fibers were examined respectively on days 2,4,7,14 and 21 under both shortened and lengthened immobilization, and then the effect of passive stretch on soleus muscle atrophy in immobilized rats was observed. Results When shortened immobilization was applied for 4 days, SOL weight (wet weight ) became lighter, the fiber cross-sectional area (CSA) shrank, and type Ⅰ muscle fibers started to transform into type Ⅱ, which all indicated that immobilized muscles began to atrophy, and as immobilization proceeded, muscle atrophy proceeded toward higher level. In contrast to that, when lengthened immobilization was applied, SOL didn't show any signs of atrophy until day 7, the sign reached its highest level on day 14 and maintained that level even though immobilization continued. Conclusion From the results, we conclude that the passive stretch can either relieve or retard the disused muscle atrophy.

  10. Cryotherapy Reduces Inflammatory Response Without Altering Muscle Regeneration Process and Extracellular Matrix Remodeling of Rat Muscle.

    Science.gov (United States)

    Vieira Ramos, Gracielle; Pinheiro, Clara Maria; Messa, Sabrina Peviani; Delfino, Gabriel Borges; Marqueti, Rita de Cássia; Salvini, Tania de Fátima; Durigan, Joao Luiz Quagliotti

    2016-01-04

    The application of cryotherapy is widely used in sports medicine today. Cooling could minimize secondary hypoxic injury through the reduction of cellular metabolism and injury area. Conflicting results have also suggested cryotherapy could delay and impair the regeneration process. There are no definitive findings about the effects of cryotherapy on the process of muscle regeneration. The aim of the present study was to evaluate the effects of a clinical-like cryotherapy on inflammation, regeneration and extracellular matrix (ECM) remodeling on the Tibialis anterior (TA) muscle of rats 3, 7 and 14 days post-injury. It was observed that the intermittent application of cryotherapy (three 30-minute sessions, every 2 h) in the first 48 h post-injury decreased inflammatory processes (mRNA levels of TNF-α, NF-κB, TGF-β and MMP-9 and macrophage percentage). Cryotherapy did not alter regeneration markers such as injury area, desmin and Myod expression. Despite regulating Collagen I and III and their growth factors, cryotherapy did not alter collagen deposition. In summary, clinical-like cryotherapy reduces the inflammatory process through the decrease of macrophage infiltration and the accumulation of the inflammatory key markers without influencing muscle injury area and ECM remodeling.

  11. A Standardized Rat Model of Volumetric Muscle Loss Injury for the Development of Tissue Engineering Therapies

    Science.gov (United States)

    2012-12-01

    conditions, making this assessment advantageous for the study of VML. However, hypertrophy of the EDL muscle in response to VML injury (Table 1) would...prevents com- pensatory hypertrophy of overloaded mouse extensor digito- rum longus muscle . J Appl Physiol. 1992;73:2538–2543. 34. Rosenblatt JD, Yong...D, Parry DJ. Satellite cell activity is re- quired for hypertrophy of overloaded adult rat muscle . Muscle Nerve. 1994;17:608–613. 35. Corona BT

  12. Electrical Stimulation of Denervated Rat Skeletal Muscle Retards Capillary and Muscle Loss in Early Stages of Disuse Atrophy

    Directory of Open Access Journals (Sweden)

    Kouki Nakagawa

    2017-01-01

    Full Text Available The purpose of the present study is to investigate the effects of low-frequency electrical muscle stimulation (ES on the decrease in muscle mass, fiber size, capillary supply, and matrix metalloproteinase (MMP immunoreactivity in the early stages of denervation-induced limb disuse. Direct ES was performed on the tibialis anterior muscle following denervation in seven-week-old male rats. The rats were divided into the following groups: control (CON, denervation (DN, and denervation with direct ES (DN + ES. Direct ES was performed at an intensity of 16 mA and a frequency of 10 Hz for 30 min per day, six days a week, for one week. We performed immunohistochemical staining to determine the expression of dystrophin, CD34, and MMP-2 in transverse sections of TA muscles. The weight, myofiber cross-sectional area (FCSA, and capillary-to-fiber (C/F ratio of the tibialis anterior (TA muscle were significantly reduced in the DN group compared to the control and DN + ES groups. The MMP-2 positive area was significantly greater in DN and DN + ES groups compared to the control group. These findings suggest beneficial effects of direct ES in reducing muscle atrophy and capillary regression without increasing MMP-2 immunoreactivity in the early stages of DN-induced muscle disuse in rat hind limbs.

  13. Optimizing hyaluronidase dose and plasmid DNA delivery greatly improves gene electrotransfer efficiency in rat skeletal muscle

    DEFF Research Database (Denmark)

    Åkerström, Thorbjörn; Vedel, Kenneth; Needham Andersen, Josefine

    2015-01-01

    Transfection of rat skeletal muscle in vivo is a widely used research model. However, gene electrotransfer protocols have been developed for mice and yield variable results in rats. We investigated whether changes in hyaluronidase pre-treatment and plasmid DNA delivery can improve transfection...... efficiency in rat skeletal muscle. We found that pre-treating the muscle with a hyaluronidase dose suitable for rats (0.56. U/g b.w.) prior to plasmid DNA injection increased transfection efficiency by >200% whereas timing of the pre-treatment did not affect efficiency. Uniformly distributing plasmid DNA...... delivery across the muscle by increasing the number of plasmid DNA injections further enhanced transfection efficiency whereas increasing plasmid dose from 0.2 to 1.6. μg/g b.w. or vehicle volume had no effect. The optimized protocol resulted in ~80% (CI95%: 79-84%) transfected muscle fibers...

  14. Enhancement of aging rat laryngeal muscles with endogenous growth factor treatment.

    Science.gov (United States)

    Stemple, Joseph C; Andreatta, Richard D; Seward, Tanya S; Angadi, Vrushali; Dietrich, Maria; McMullen, Colleen A

    2016-05-01

    Clinical evidence suggests that laryngeal muscle dysfunction is associated with human aging. Studies in animal models have reported morphological changes consistent with denervation in laryngeal muscles with age. Life-long laryngeal muscle activity relies on cytoskeletal integrity and nerve-muscle communication at the neuromuscular junction (NMJ). It is thought that neurotrophins enhance neuromuscular transmission by increasing neurotransmitter release. We hypothesized that treatment with neurotrophin 4 (NTF4) would modify the morphology and functional innervation of aging rat laryngeal muscles. Fifty-six Fischer 344xBrown Norway rats (6- and 30-mo age groups) were used to evaluate to determine if NTF4, given systemically (n = 32) or directly (n = 24), would improve the morphology and functional innervation of aging rat thyroarytenoid muscles. Results demonstrate the ability of rat laryngeal muscles to remodel in response to neurotrophin application. Changes were demonstrated in fiber size, glycolytic capacity, mitochondrial, tyrosine kinase receptors (Trk), NMJ content, and denervation in aging rat thyroarytenoid muscles. This study suggests that growth factors may have therapeutic potential to ameliorate aging-related laryngeal muscle dysfunction.

  15. Calcium regulation of oxidative phosphorylation in rat skeletal muscle mitochondria.

    Science.gov (United States)

    Kavanagh, N I; Ainscow, E K; Brand, M D

    2000-02-24

    Activation of oxidative phosphorylation by physiological levels of calcium in mitochondria from rat skeletal muscle was analysed using top-down elasticity and regulation analysis. Oxidative phosphorylation was conceptually divided into three subsystems (substrate oxidation, proton leak and phosphorylation) connected by the membrane potential or the protonmotive force. Calcium directly activated the phosphorylation subsystem and (with sub-saturating 2-oxoglutarate) the substrate oxidation subsystem but had no effect on the proton leak kinetics. The response of mitochondria respiring on 2-oxoglutarate at two physiological concentrations of free calcium was quantified using control and regulation analysis. The partial integrated response coefficients showed that direct stimulation of substrate oxidation contributed 86% of the effect of calcium on state 3 oxygen consumption, and direct activation of the phosphorylation reactions caused 37% of the increase in phosphorylation flux. Calcium directly activated phosphorylation more strongly than substrate oxidation (78% compared to 45%) to achieve homeostasis of mitochondrial membrane potential during large increases in flux.

  16. Leucine-enriched essential amino acids attenuate muscle soreness and improve muscle protein synthesis after eccentric contractions in rats.

    Science.gov (United States)

    Kato, Hiroyuki; Suzuki, Hiromi; Mimura, Masako; Inoue, Yoshiko; Sugita, Mayu; Suzuki, Katsuya; Kobayashi, Hisamine

    2015-06-01

    Eccentric exercise results in prolonged muscle weakness and muscle soreness, which are typical symptoms of muscle damage. Recovery from muscle damage is related to mammalian target of rapamycin (mTOR) activity. Leucine-enriched essential amino acids (LEAAs) stimulate muscle protein synthesis via activation of the mTOR pathway. Therefore, we investigated the effect of LEAAs on muscle protein synthesis and muscle soreness after eccentric contractions (EC). Male Sprague-Dawley rats (9-11 weeks old) were administered an LEAA solution (AminoL40; containing 40 % leucine and 60 % other essential amino acids) at 1 g/kg body weight or distilled water (control) 30 min before and 10 min after EC. Tibialis anterior (TA) muscle was exposed to 500 EC by electrical stimulation under anesthesia. The fractional synthesis rate (FSR; %/h) in the TA muscle was measured by incorporating L-[ring-(2)H5] phenylalanine into skeletal muscle protein. Muscle soreness was evaluated by the paw withdrawal threshold using the Randal-Selitto test with some modifications from 1 to 3 days after EC. The FSR in the EC-control group (0.147 ± 0.016 %/h) was significantly lower than in the sedentary group (0.188 ± 0.016 %/h, p < 0.05). AminoL40 administration significantly mitigated the EC-induced impairment of the FSR (0.172 ± 0.018 %/h). EC decreased the paw withdrawal threshold at 1 and 2 days after EC, which indicated that EC induced muscle soreness. Furthermore, AminoL40 administration alleviated the decreased paw withdrawal threshold. These findings suggest that LEAA supplementation improves the rate of muscle protein synthesis and ameliorates muscle soreness after eccentric exercise.

  17. Altered aortic and cremaster muscle prostaglandin synthesis in diabetic rats

    Energy Technology Data Exchange (ETDEWEB)

    Myers, T.O.; Messina, E.J.; Rodrigues, A.M.; Gerritsen, M.E.

    1985-10-01

    Alterations in the synthesis and release of prostaglandins have been reported in humans and animal models of diabetes mellitus. In the present study synthesis and release of prostaglandins by thoracic aorta and cremaster muscle of rats with streptozotocin-induced diabetes of 8 wk duration was compared with age-matched controls. Prostaglandin synthesis was assessed by the measurement of immunoreactive prostaglandin E2 (PGE2) and 6-ketoprostaglandin F1 alpha (6-keto-PGF1 alpha) release and by quantifying metabolism of exogenous (1- UC)arachidonic acid by thoracic aortic rings and minced cremaster muscle. These studies indicate that diminished prostacyclin (PGI2) and/or PGE2 production is not a general feature of all diabetic vascular tissues, suggesting that large and small blood vessels may not be similarly affected by diabetes in regard to the metabolism of exogenous arachidonic acid and the synthesis and release of prostaglandins. Furthermore, the vascular changes often observed in conjunction with diabetes, i.e., alterations in vascular reactivity and microangiopathy in small blood vessels and atherosclerosis of large blood vessels may be related in some way to the segmental differences observed in prostaglandin synthesis.

  18. Muscle-specific changes in length-force characteristics of the calf muscles in the spastic Han-Wistar rat.

    Science.gov (United States)

    Olesen, Annesofie T; Jensen, Bente R; Uhlendorf, Toni L; Cohen, Randy W; Baan, Guus C; Maas, Huub

    2014-11-01

    The purpose of the present study was to investigate muscle mechanical properties and mechanical interaction between muscles in the lower hindlimb of the spastic mutant rat. Length-force characteristics of gastrocnemius (GA), soleus (SO), and plantaris (PL) were assessed in anesthetized spastic and normally developed Han-Wistar rats. In addition, the extent of epimuscular myofascial force transmission between synergistic GA, SO, and PL, as well as between the calf muscles and antagonistic tibialis anterior (TA), was investigated. Active length-force curves of spastic GA and PL were narrower with a reduced maximal active force. In contrast, active length-force characteristics of spastic SO were similar to those of controls. In reference position (90° ankle and knee angle), higher resistance to ankle dorsiflexion and increased passive stiffness was found for the spastic calf muscle group. At optimum length, passive stiffness and passive force of spastic GA were decreased, whereas those of spastic SO were increased. No mechanical interaction between the calf muscles and TA was found. As GA was lengthened, force from SO and PL declined despite a constant muscle-tendon unit length of SO and PL. However, the extent of this interaction was not different in spastic rats. In conclusion, the effects of spasticity on length-force characteristics were muscle specific. The changes observed for GA and PL muscles are consistent with the changes in limb mechanics reported for human patients. Our results indicate that altered mechanics in spastic rats cannot be attributed to differences in mechanical interaction, but originate from individual muscular structures. Copyright © 2014 the American Physiological Society.

  19. Muscle relaxant and neurotoxic activities of intrathecal baclofen in rats.

    Science.gov (United States)

    Kuroiwa, Miho; Kitano, Yutaka; Takasuna, Kiyoshi; Manabe, Sunao; Saito, Takao

    2009-11-01

    Intrathecal baclofen therapy by the continuous intrathecal infusion of baclofen has been shown to be an effective treatment for spasticity in patients with spinal cord injury, cerebral palsy, traumatic brain injury, multiple sclerosis and other disorders. To demonstrate the efficacy and safety of intrathecal baclofen therapy, we investigated the muscle relaxant and neurotoxic activities of intrathecal baclofen in rats, compared with intravenous baclofen. Intrathecal and intravenous administration of baclofen dose-dependently inhibited the anemic decerebrate rigidity with ED(50) values of 0.31microg/animal (=1.1-1.3microg/kg) and 0.43mg/kg, respectively. Intrathecal administration of baclofen induced no noticeable changes in a spontaneous electroencephalogram at 30microg/animal. Intravenous administration of baclofen induced an abnormal electroencephalogram with flat waves in all the animals and the no-observed-effect level was estimated to be 5mg/kg. In some animals, intravenous administration of baclofen induced sporadic spikes or sharp waves with background flat waves, indicating inhibitory and excitatory effects on the central nervous system. In conclusion, intrathecal administration of baclofen dose-dependently inhibited anemic decerebrate rigidity in rats and the effective dose was more than 300 times lower than that of intravenous baclofen. The safety margin of intrathecal baclofen was greater than that of intravenous baclofen (> or =97 versus 12). These results suggest that intrathecal baclofen therapy is superior to systemic baclofen therapy in both efficacy and safety.

  20. Changes in antioxidant enzymes and lipid peroxidation in extensor digitorum longus muscles of streptozotocin-diabetic rats may contribute to muscle atrophy.

    Science.gov (United States)

    Nonaka, Koji; Une, S; Tatsuta, N; Ito, K; Akiyama, J

    2014-12-01

    We investigated muscle atrophy, major antioxidant enzymes and lipid peroxidation in the extensor digitorum longus (EDL, predominantly fast fibers) and soleus (predominantly slow fibers) muscle of streptozotocin-diabetic rats. Female Wistar rats were divided into a control (n = 5) and streptozotocin-induced diabetic group (n = 5). Eight weeks after diabetes induction the EDL and soleus muscles were removed and catalase (CAT), glutathione peroxidase (GPX) and superoxide dismutase activity (SOD), and thiobarbituric acid reactive substances (TBARS) levels measured. The CAT activity increased in both the EDL and soleus muscles of the diabetic rats (p muscle (p muscle of the diabetic rats (p muscles showed significant atrophy but the EDL muscle elicited the greatest atrophy. In conclusion, it appears that adaptive responses to oxidative stress were adequate in the soleus muscle, but not in the EDL muscle, of diabetic rats. Thus fast twitch muscle fibers may be more susceptible to oxidative stress than slow twitch muscle fibers and this may contribute to muscle atrophy under diabetic conditions.

  1. Abnormalities in the Fiber Composition and Capillary Architecture in the Soleus Muscle of Type 2 Diabetic Goto-Kakizaki Rats

    Directory of Open Access Journals (Sweden)

    Shinichiro Murakami

    2012-01-01

    Full Text Available Type 2 diabetes mellitus is linked to impaired skeletal muscle glucose uptake and storage. This study aimed to investigate the fiber type distributions and the three-dimensional (3D architecture of the capillary network in the skeletal muscles of type 2 diabetic rats. Muscle fiber type transformation, succinate dehydrogenase (SDH activity, capillary density, and 3D architecture of the capillary network in the soleus muscle were determined in 36-week-old Goto-Kakizaki (GK rats as an animal model of nonobese type 2 diabetes and age-matched Wistar (Cont rats. Although the soleus muscle of Cont rats comprised both type I and type IIA fibers, the soleus muscle of GK rats had only type I fibers. In addition, total SDH activity in the soleus muscle of GK rats was significantly lower than that in Cont rats because GK rats had no high-SDH activity type IIA fiber in the soleus muscle. Furthermore, the capillary diameter, capillary tortuosity, and microvessel volume in GK rats were significantly lower than those in Cont rats. These results indicate that non-obese diabetic GK rats have muscle fiber type transformation, low SDH activity, and reduced skeletal muscle capillary content, which may be related to the impaired glucose metabolism characteristic of type 2 diabetes.

  2. Distinct muscle apoptotic pathways are activated in muscles with different fiber types a rat model of critical illness myopathy

    Science.gov (United States)

    Barnes, Benjamin T.; Confides, Amy L.; Rich, Mark M.; Dupont-Versteegden, Esther E.

    2015-01-01

    Critical illness myopathy (CIM) is associated with severe muscle atrophy and fatigue in affected patients. Apoptotic signaling is involved in atrophy and is elevated in muscles from patients with CIM. In this study we investigated underlying mechanisms of apoptosis-related pathways in muscles with different fiber type composition in a rat model of CIM using denervation and glucocorticoid administration (denervation and steroid-induced myopathy, DSIM). Soleus and tibialis anterior (TA) muscles showed severe muscle atrophy (40–60% of control muscle weight) and significant apoptosis in interstitial as well as myofiber nuclei that was similar between the two muscles with DSIM. Caspase-3 and −8 activities, but not caspase-9 and −12, were elevated in TA and not in soleus muscle, while the caspase-independent proteins endonuclease G (EndoG) and apoptosis inducing factor (AIF) were not changed in abundance nor differentially localized in either muscle. Anti-apoptotic proteins HSP70, −27, and apoptosis repressor with a caspase recruitment domain (ARC) were elevated in soleus compared to TA muscle and ARC was significantly decreased with induction of DSIM in soleus. Results indicate that apoptosis is a significant process associated with DSIM in both soleus and TA muscles, and that apoptosis-associated processes are differentially regulated in muscles of different function and fiber type undergoing atrophy due to DSIM. We conclude that interventions combating apoptosis with CIM may need to be directed towards inhibiting caspase-dependent as well as -independent mechanisms to be able to affect muscles of all fiber types. PMID:25740800

  3. Distinct muscle apoptotic pathways are activated in muscles with different fiber types in a rat model of critical illness myopathy.

    Science.gov (United States)

    Barnes, Benjamin T; Confides, Amy L; Rich, Mark M; Dupont-Versteegden, Esther E

    2015-06-01

    Critical illness myopathy (CIM) is associated with severe muscle atrophy and fatigue in affected patients. Apoptotic signaling is involved in atrophy and is elevated in muscles from patients with CIM. In this study we investigated underlying mechanisms of apoptosis-related pathways in muscles with different fiber type composition in a rat model of CIM using denervation and glucocorticoid administration (denervation and steroid-induced myopathy, DSIM). Soleus and tibialis anterior (TA) muscles showed severe muscle atrophy (40-60% of control muscle weight) and significant apoptosis in interstitial as well as myofiber nuclei that was similar between the two muscles with DSIM. Caspase-3 and -8 activities, but not caspase-9 and -12, were elevated in TA and not in soleus muscle, while the caspase-independent proteins endonuclease G (EndoG) and apoptosis inducing factor (AIF) were not changed in abundance nor differentially localized in either muscle. Anti-apoptotic proteins HSP70, -27, and apoptosis repressor with a caspase recruitment domain (ARC) were elevated in soleus compared to TA muscle and ARC was significantly decreased with induction of DSIM in soleus. Results indicate that apoptosis is a significant process associated with DSIM in both soleus and TA muscles, and that apoptosis-associated processes are differentially regulated in muscles of different function and fiber type undergoing atrophy due to DSIM. We conclude that interventions combating apoptosis with CIM may need to be directed towards inhibiting caspase-dependent as well as -independent mechanisms to be able to affect muscles of all fiber types.

  4. Glucose metabolism in rats submitted to skeletal muscle denervation

    Directory of Open Access Journals (Sweden)

    Wilton Marlindo Santana Nunes

    2005-07-01

    Full Text Available This study analyzed the local and systemic effects of immobilization by denervation of the skeletal muscle on glucose metabolism. The rats were submitted to section of the right paw sciatic nerve. A reduction was observed in glucose uptake by the isolated soleus muscle of the denervated paw after 3 and 7 days, but not after 28 days in relation to the control animals. There was no difference after 3 and 7 days in glucose uptake by the soleus muscle of the opposite intact paw in relation to the control. There was increased glucose uptake in the same paw 28 days after denervation. The rate of glucose removal in response to exogenous insulin after 28 days of denervation was significantly higher than in control animals and those observed after 3 and 7 days of denervation. These results suggest that immobilization by denervation interfered not only in glucose metabolism in the skeletal muscle involved but also in other tissues.O estudo analisou os efeitos locais e sistêmicos da imobilização por desnervação do músculo esquelético sobre o metabolismo glicidico. Ratos foram submetidos à secção do nervo ciático da pata direita. Observou-se redução da captação de glicose pelo músculo sóleo isolado da pata desnervada após 3 e 7 mas não após 28 dias em relação a animais controle. Não houve diferença após 3 e 7 dias na captação de glicose pelo músculo sóleo da pata contralateral intacta em relação ao controle. Houve aumento da captação de glicose nesta mesma pata 28 dias após a desnervação. A taxa de remoção da glicose em resposta à insulina exógena após 28 dias de desnervação foi significantemente superior à do controle e àquelas observadas após 3 e 7 dias da desnervação. Esses resultados sugerem que a imobilização por desnervação interfere não só no metabolismo da glicose no músculo esquelético envolvido como também em outros tecidos.

  5. Activation of estrogen response elements is mediated both via estrogen and muscle contractions in rat skeletal muscle myotubes

    DEFF Research Database (Denmark)

    Wiik, A.; Hellsten, Ylva; Berthelson, P.

    2009-01-01

    The aim of the present study was to investigate the activation of estrogen response elements (EREs) by estrogen and muscle contractions in rat myotubes in culture and to assess whether the activation is dependent on the estrogen receptors (ERs). In addition, the effect of estrogen and contraction...... increased (P estrogen and attenuated (P estrogen-induced transactivation is mediated via ERs, the effect of muscle contraction...... is ER independent. The muscle contraction-induced transactivation of ERE and increase in ERbeta mRNA were instead found to be MAP kinase (MAPK) dependent. This study demonstrates for the first time that muscle contractions have a similar functional effect as estrogen in skeletal muscle myotubes, causing...

  6. Motor Unit Changes Seen With Skeletal Muscle Sarcopenia in Oldest Old Rats

    Science.gov (United States)

    Kung, Theodore A.; van der Meulen, Jack H.; Urbanchek, Melanie G.; Kuzon, William M.; Faulkner, John A.

    2014-01-01

    Sarcopenia leads to many changes in skeletal muscle that contribute to atrophy, force deficits, and subsequent frailty. The purpose of this study was to characterize motor unit remodeling related to sarcopenia seen in extreme old age. Whole extensor digitorum longus muscle and motor unit contractile properties were measured in 19 adult (11–13 months) and 12 oldest old (36–37 months) Brown-Norway rats. Compared with adults, oldest old rats had significantly fewer motor units per muscle, smaller muscle cross-sectional area, and lower muscle specific force. However, mean motor unit force generation was similar between the two groups due to an increase in innervation ratio by the oldest old rats. These findings suggest that even in extreme old age both fast- and slow-twitch motor units maintain the ability to undergo motor unit remodeling that offsets some effects of sarcopenia. PMID:24077596

  7. Contractile Properties of Esophageal Striated Muscle: Comparison with Cardiac and Skeletal Muscles in Rats

    Directory of Open Access Journals (Sweden)

    Takahiko Shiina

    2010-01-01

    Full Text Available The external muscle layer of the mammalian esophagus consists of striated muscles. We investigated the contractile properties of esophageal striated muscle by comparison with those of skeletal and cardiac muscles. Electrical field stimulation with single pulses evoked twitch-like contractile responses in esophageal muscle, similar to those in skeletal muscle in duration and similar to those in cardiac muscle in amplitude. The contractions of esophageal muscle were not affected by an inhibitor of gap junctions. Contractile responses induced by high potassium or caffeine in esophageal muscle were analogous to those in skeletal muscle. High-frequency stimulation induced a transient summation of contractions followed by sustained contractions with amplitudes similar to those of twitch-like contractions, although a large summation was observed in skeletal muscle. The results demonstrate that esophageal muscle has properties similar but not identical to those of skeletal muscle and that some specific properties may be beneficial for esophageal peristalsis.

  8. Changes of contractile responses due to simulated weightlessness in rat soleus muscle

    Science.gov (United States)

    Elkhammari, A.; Noireaud, J.; Léoty, C.

    1994-08-01

    Some contractile and electrophysiological properties of muscle fibers isolated from the slow-twitch soleus (SOL) and fast-twitch extensor digitorum longus (EDL) muscles of rats were compared with those measured in SOL muscles from suspended rats. In suspendede SOL (21 days of tail-suspension) membrane potential (Em), intracellular sodium activity (aiNa) and the slope of the relationship between Em and log [K]o were typical of fast-twitch muscles. The relation between the maximal amplitude of K-contractures vs Em was steeper for control SOL than for EDL and suspended SOL muscles. After suspension, in SOL muscles the contractile threshold and the inactivation curves for K-contractures were shifted to more positive Em. Repriming of K-contractures was unaffected by suspencion. The exposure of isolated fibers to perchlorate (ClO4-)-containing (6-40 mM) solutions resulted ina similar concentration-dependent shift to more negative Em of activation curves for EDL and suspended SOL muscles. On exposure to a Na-free TEA solution, SOL from control and suspended rats, in contrast to EDL muscles, generated slow contractile responses. Suspended SOL showed a reduced sensitivity to the contracture-producing effect of caffeine compared to control muscles. These results suggested that the modification observed due to suspension could be encounted by changes in the characteristics of muscle fibers from slow to fast-twitch type.

  9. A semiquantitative scoring tool to evaluate eccentric exercise-induced muscle damage in trained rats.

    Science.gov (United States)

    Rizo-Roca, D; Ríos-Kristjánsson, J G; Núñez-Espinosa, C; Ascensão, A; Magalhães, J; Torrella, J R; Pagès, T; Viscor, G

    2015-11-02

    Unaccustomed eccentric exercise is a well-documented cause of exercise-induced muscle damage. However, in trained subjects muscle injury involves only light or moderate tissue damage. Since trained rats are widely used as a model for skeletal muscle injury, here we propose a semiquantitative scoring tool to evaluate muscle damage in trained rats. Twenty male Sprague-Dawley rats were trained fortwo weeks following a two-week preconditioning period, and randomly divided into two groups: control rats (CTL; n=5) and rats with eccentric exercise-induced muscle damage (INJ; n=15). Injured rats were sacrificed at three time points: 1, 3 and 7 days post injury (n=5 each). Transverse sections from the right soleus were cut (10 µm) and stained with haematoxylin-eosin. Samples were evaluated by two groups of observers (four researchers experienced in skeletal muscle histopathology and four inexperienced) using the proposed tool, which consisted of six items organised in three domains: abnormal fibre morphology, necrotic/(re)degenerating fibres (muscle fibre domain), endomysial and perimysial infiltration (inflammatory state domain) and endomysium and perimysium distension (interstitial compartment domain). We observed the expected time course in the six evaluated items. Furthermore, agreement among observers was evaluated by measuring the Intraclass Correlation Coefficient (ICC). Within the experienced group, items from the muscle fibre and interstitial compartment domains showed good agreement and the two items from the infiltration compartment domain showed excellent agreement. in conclusion, the proposed tool allowed quick and correct evaluation of light to moderate muscle damage in trained rats with good agreement between observers.

  10. Effect of diltiazem on skeletal muscle 3-O-methylglucose transport in bacteremic rats

    Energy Technology Data Exchange (ETDEWEB)

    Westfall, M.V.; Sayeed, M.M.

    1989-03-01

    This study examined whether alterations in cellular Ca2+ regulation contribute to previously observed changes in skeletal muscle sugar transport during bacteremia. Fasted male rats received saline (control) or bacteria (4 X 10(10) Escherichia coli/kg) intraperitoneally. Twelve hours later, basal and insulin-mediated 3-O-methylglucose (3MG) transport was measured in isolated soleus muscles. Measurements of 3MG transport in the presence of cytochalasin b or at a low temperature (0.5 degree C) indicated that altered sugar transport in bacteremic rat muscles was not due to nonspecific membrane permeability changes. To determine the role of Ca2+ in the pathogenesis of altered sugar transport during bacteremia, rats were treated with the Ca2+ antagonist diltiazem (DZ, 0.6-2.4 mg/kg) at various times (0, 0 + 7.5, 10 h) after saline or bacterial injection. In bacteremic rats given 2.4 mg/kg DZ at 10 h, basal and insulin-mediated transport were similar to control values. This dose of DZ had little effect on control muscles. The addition of 20 microM DZ to the incubation media did not affect basal or insulin-mediated 3MG transport in bacteremic rat muscles. Addition of the Ca2+ agonist BAY K 8644 to the incubation media had no effect on sugar transport in bacteremic rat muscles but caused alterations in control rat muscles that were comparable to those observed in bacteremia. These results suggest that alterations in Ca2+ regulation could contribute to the previously observed changes in sugar transport in skeletal muscles from bacteremic rats.

  11. Gated /sup 31/P NMR study of tetanic contraction in rat muscle depleted of phosphocreatine

    Energy Technology Data Exchange (ETDEWEB)

    Shoubridge, E.A.; Radda, G.K.

    1987-05-01

    Rats were fed a diet containing 1% ..beta..-guanidino-propionic acid (GPA) for 6-12 wk to deplete their muscles of phosphocreatine (PCr). Gated /sup 31/P nuclear magnetic resonance (NMR) spectra were obtained from the gastrocnemius-plantaris muscle at various time points during either a 1- or 3-s isometric tetanic contraction using a surface coil. The energy cost of a 1-s tetanus in unfatigued control rat muscle was 48.4 ..mu..mol ATP x g dry wt/sup -1/ x s/sup -1/ and was largely supplied by PCr; anaerobic glycogenolysis was negligible. In GPA-fed rats PCr was undetectable after 400 ms. This had no effect on initial force generated per gram, which was not significantly different from controls. Developed tension in a 3-s tetanus in GPA-fed rats could be divided into a peak phase (duration 0.8-0.9 s) and a plateau phase (65% peak tension) in which PCr was undetectable and the (ATP) was < 20% of that in control muscle. Energy from glycogenolysis was sufficient to maintain force generation at this submaximal level. Mean net glycogen utilization per 3-s tetanus was 78% greater than in control muscle. However, the observed decrease in intracellular pH was less than that expected from energy budget calculations, suggesting either increased buffering capacity or modulation of ATP hydrolysis in the muscles of GPA-fed rats. The results demonstrate that the transport role of PCr is not essential in contracting muscle in GPA-fed rats. PCr is probably important in this regard in the larger fibers of control muscle. Although fast-twitch muscles depleted of PCr have nearly twice the glycogen reserves of control muscle, glycogenolysis is limited in its capacity to fill the role of PCr as an energy buffer under conditions of maximum ATP turnover.

  12. Peripheral benzodiazepine binding sites on striated muscles of the rat: Properties and effect of denervation

    Energy Technology Data Exchange (ETDEWEB)

    Mueller, W.E.; Ickstadt, A. (Mainz Univ. (Germany, F.R.). Pharmakologisches Inst.); Hopf, H.Ch. (Mainz Univ. (Germany, F.R.))

    1985-01-01

    In order to test the hypothesis that peripheral benzodiazepine binding sites mediate some direct effects of benzodiazepines on striated muscles, the properties of specific /sup 3/H-Ro 5-4864 binding to rat biceps and rat diaphragm homogenates were investigated. In both tissues a single population of sites was found with a Ksub(D) value of 3 nmol/l. The density of these sites in both muscles was higher than the density in rat brain, but was considerably lower than in rat kidney. Competition experiments indicate a substrate specificity of specific /sup 3/H-Ro 5-4864 binding similar to the properties already demonstrated for the specific binding of this ligand to peripheral benzodiazepine binding sites in many other tissues. The properties of these sites in the rat diaphragm are not changed after motoric denervation by phrenicectomy. It is concluded that peripheral benzodiazepine binding sites are not involved in direct effects of benzodiazepines on striated muscles.

  13. Avaliação do dimorfismo sexual e da relação entre as características craniofaciais, dos arcos dentários e do músculo masseter na fase de dentição mista

    OpenAIRE

    Maria Carolina Salomé Marquezin; Annicele da Silva Andrade; Moara De Rossi; Gustavo Hauber Gameiro; Maria Beatriz Duarte Gavião; Paula Midori Castelo

    2014-01-01

    Purposeto evaluate sexual dimorphism and the relationship between craniofacial characteristics, dental arch morphology and masseter muscle thickness in children in the mixed dentition stage. Methodthe study sample comprised 32 children, aged 6-10 years (14♀/18♂) with normal occlusion. Craniofacial characteristics, dental morphology and masseter muscle thickness were evaluated by means of posteroanterior cephalometric radiographs, dental cast evaluation and ultrasound exam, respectively. The r...

  14. [Morphohistochemical study of skeletal muscles in rats after experimental flight on "Kosmos-1887"].

    Science.gov (United States)

    Il'ina-Kakueva, E I

    1990-01-01

    Morphometric and histochemical methods were used to examine the soleus, gastrocnemius (medial portion), quadriceps femoris (central portion) and biceps brachii muscles of Wistar SPF rats two days after the 13-day flight on Cosmos-1887. It was found that significant atrophy developed only in the soleus muscle. The space flight did not change the percentage content of slow (type I) and fast (type II) fibers in fast twitch muscles. During two days at 1 g the slow soleus muscle developed substantial circulation disorders, which led to interstitial edema and necrotic changes. The gastrocnemius muscle showed small foci containing necrotic myofibers. Two days after recovery no glycogen aggregates were seen in myofibers, which were previously observed in other rats examined 4--8 hours after flight. An initial stage of muscle readaptation to 1 g occurred, when NAD.H2-dehydrogenase activity was decreased.

  15. Eccentric contractions affect muscle membrane phospholipid fatty acid composition in rats

    DEFF Research Database (Denmark)

    Helge, Jørn Wulff; Therkildsen, K J; Jørgensen, T B

    2001-01-01

    This study investigated if prior eccentric contractions, and thus mechanical strain and muscle damage, exert an effect on the muscle membrane phospholipid fatty acid composition in rats, and whether a possible effect could be attenuated by dietary supplements. Twenty-three rats were randomised...... to three groups who received chow with added fish oil (n = 8), vitamin C (n = 8) or no supplement (n = 7). After 3 weeks of feeding, calf muscles on one side were stimulated electrically during anaesthesia causing eccentric contractions. Two days later the white gastrocnemius, a part of the stimulated calf...... muscle, was excised from both legs. In the muscles stimulated to contract eccentrically, compared to the control muscles, the proportion of arachidonic acid, C20:4,n-6 (17.7 +/- 0.6; 16.4 +/- 0.4% of total fatty acids, respectively) and docosapentanoeic acid, C22:5,n-3 (2.9 +/- 0.1 and 2.7 +/- 0...

  16. Detection of histidine decarboxylase in rat aorta and cultured rat aortic smooth muscle cells.

    Science.gov (United States)

    Tippens, A S; Davis, S V; Hayes, J R; Bryda, E C; Green, T L; Gruetter, C A

    2004-08-01

    Having previously demonstrated release of histamine from mast-cell-deficient rat aorta, the objective of this study was to determine and localize histamine synthesis capability in the aorta by detecting histidine decarboxylase (HDC), the enzyme that catalyzes histamine formation. Experiments were conducted with nested reverse transcription-polymerase chain reaction (nRT-PCR) to detect HDC mRNA and with immunofluorescence and western blot analysis to detect HDC protein in rat aorta, cultured rat aortic smooth muscle (RASMC) and endothelial cells (RAEC). Gel electrophoresis of nRT-PCR products indicated HDC mRNA in liver, aorta and RASMC but not in RAEC or kidney. Sequence analysis confirmed that the band observed in RASMC was the target HDC amplicon. Immunofluorescence indicated the presence of HDC protein in RASMC and not in RAEC. Western Blot analysis revealed HDC protein (55 kDa) in liver, aorta, RASMC but not in RAEC or kidney. The results of this study are the first to demonstrate the presence of HDC mRNA and protein in rat aorta and more specifically in RASMC, indicative of their capability to synthesize histamine. Copyright 2004 Birkhäuser Verlag, Basel

  17. Wortmannin inhibits both insulin- and contraction-stimulated glucose uptake and transport in rat skeletal muscle

    DEFF Research Database (Denmark)

    Wojtaszewski, Jørgen; Hansen, B F; Ursø, Birgitte

    1996-01-01

    The role of phosphatidylinositol (PI) 3-kinase for insulin- and contraction-stimulated muscle glucose transport was investigated in rat skeletal muscle perfused with a cell-free perfusate. The insulin receptor substrate-1-associated PI 3-kinase activity was increased sixfold upon insulin stimulat...

  18. Sub-sarcolemmal swelling of sarcoplasmic reticulum after isometric contractions in rat semimembranosus lateralis muscle

    NARCIS (Netherlands)

    Willems, M.E.T.; Huijing, P.A.J.B.M.; Friden, J.

    1999-01-01

    The decline in isometric force, swelling of sarcoplasmic reticulum and loss of desmin was measured in semimembranosus lateralis muscle of male Wistar rats immediately after a short series of brief (500 ms) maximal isometric contractions. For the active muscle, the series ended below (protocol A) and

  19. Electrophysiological, histochemical, and hormonal adaptation of rat muscle after prolonged hindlimb suspension

    Science.gov (United States)

    Kourtidou-Papadeli, Chrysoula; Kyparos, Antonios; Albani, Maria; Frossinis, Athanasios; Papadelis, Christos L.; Bamidis, Panagiotis; Vivas, Ana; Guiba-Tziampiri, Olympia

    2004-05-01

    The perspective of long-duration flights for future exploration, imply more research in the field of human adaptation. Previous studies in rat muscles hindlimb suspension (HLS), indicated muscle atrophy and a change of fibre composition from slow-to-fast twitch types. However, the contractile responses to long-term unloading is still unclear. Fifteen adult Wistar rats were studied in 45 and 70 days of muscle unweighting and soleus (SOL) muscle as well as extensor digitorum longus (EDL) were prepared for electrophysiological recordings (single, twitch, tetanic contraction and fatigue) and histochemical stainings. The loss of muscle mass observed was greater in the soleus muscle. The analysis of electrophysiological properties of both EDL and SOL showed significant main effects of group, of number of unweighting days and fatigue properties. Single contraction for soleus muscle remained unchanged but there was statistically significant difference for tetanic contraction and fatigue. Fatigue index showed a decrease for the control rats, but increase for the HLS rats. According to the histochemical findings there was a shift from oxidative to glycolytic metabolism during HLS. The data suggested that muscles atrophied, but they presented an adaptation pattern, while their endurance in fatigue was decreased.

  20. Fibre type regionalisation in lower hindlimb muscles of rabbit, rat and mouse : a comparative study

    NARCIS (Netherlands)

    Wang, LC; Kernell, D

    2001-01-01

    The topographical distribution of different fibre types in muscles of the lower hindlimb in rabbits and mice was quantitatively determined. The results were compared to those previously obtained, using the same new quantification methods, in homologous muscles of the rat. Type I fibres ('slow') were

  1. Muscle differentiation after sciatic nerve transection and reinnervation in adult rats

    NARCIS (Netherlands)

    Ijkema-Paassen, J; Meek, MF; Gramsbergen, A

    Reinnervation after peripheral nerve transections generally leads to poor functional recovery. In order to study whether changes in muscles might be a contributing factor in this phenomenon we studied muscle morphology and fibre type distributions after sciatic nerve transection in the rat hind

  2. Isolation and characterization of satellite cells from rat head branchiomeric muscles

    NARCIS (Netherlands)

    Carvajal Monroy, P.L.; Yablonka-Reuveni, Z.; Grefte, Sander; Kuijpers-Jagtman, Anne Marie; Wagener, F.A.D.T.G.; Hoff, Von den J.W.

    2015-01-01

    This protocol describes the isolation of satellite cells from branchiomeric head muscles of a 9 week-old rat. The muscles originate from different branchial arches. Subsequently, the satellite cells are cultured on a spot coating of millimeter size to study their differentiation. This approach avoid

  3. Proximo-distal organization and fibre type regionalization in rat hindlimb muscles

    NARCIS (Netherlands)

    Wang, LC; Kernell, D

    2000-01-01

    Five muscles of the rat's lower hindlimb were compared with regard to their histochemical fibre type distribution at seven different proximo-distal levels. The muscles were: extensor digitorum longus (ED), flexor digitorum and hallucis longus (FD), gastrocnemius medialis (GM), peroneus longus (PE) a

  4. Carnosine content in skeletal muscle is dependent on vitamin B6 status in rats

    Directory of Open Access Journals (Sweden)

    Sofya eSuidasari

    2016-01-01

    Full Text Available Carnosine, a histidine-containing dipeptide, is well known to be associated with skeletal muscle performance. However, there is limited information on the effect of dietary micronutrients on muscle carnosine level. Pyridoxal 5′-phosphate (PLP, the active form of vitamin B6, is involved in amino acid metabolisms in the body as a co-factor. We hypothesized that enzymes involved in β-alanine biosynthesis, the rate-limiting precursor of carnosine, may also be PLP-dependent. Thus, we examined the effects of dietary vitamin B6 on the muscle carnosine content of rats. Male and female rats were fed a diet containing 1, 7, or 35 mg pyridoxine HCl/kg for 6 weeks. Carnosine in skeletal muscles was quantified by ultra-performance liquid chromatography coupled with tandem mass spectrometry (UPLC-MS/MS. In the gastrocnemius muscle of male rats, carnosine concentration was significantly higher in the 7 and 35 mg groups (+70% and +61%, respectively than in the 1 mg pyridoxine HCl/kg group, whereas that in the soleus muscle of male rats was significantly higher only in the 7 mg group (+43% than in the 1 mg pyridoxine HCl/kg group (P<0.05. In both muscles of female rats, carnosine concentration was significantly higher in the 7 and 35 mg groups (+32% ~ +226% than in the 1 mg pyridoxine HCl/kg group (P<0.05. We also found that compared to the 1 mg group, β-alanine concentrations in the 7 and 35 mg groups were markedly elevated in gastrocnemius muscles of male (+153% and +148%, respectively, P<0.05 and female (+381% and +437%, respectively, P<0.05 rats. Noteworthy, the concentrations of ornithine in the 7 and 35 mg groups were decreased in gastrocnemius muscles of male rats (−46% and −54%, respectively, P<0.05, which strongly inversely correlated with β-alanine concentration (r=−0.84, P<0.01. In humans, 19% lower muscle carnosine content was found in soleus muscle of women of the lower plasma PLP tertile, but this was not observed in gastrocnemius muscle

  5. A linear description of shortening induced changes in isometric length-force characteristics of rat muscle

    OpenAIRE

    Meijer, K; Grootenboer, H.J.; Koopman, H.F.J.M.; Huijing, P.A.

    1996-01-01

    Active muscle shortening reduces the isometric force potential of muscle. This observation indicates that the isometric length-force characteristics are altered during muscle shortening. Post-shortening decrease in isometric force depends on starting length, shortening amplitude and shortening velocity. In the present study, post-shortening decrease in isometric force was determined after isokinetic contractions with various shortening amplitudes initiated from different lengths of rat medial...

  6. Leucine Protects Against Skeletal Muscle Atrophy in Lipopolysaccharide-Challenged Rats.

    Science.gov (United States)

    Wan, Jin; Chen, Daiwen; Yu, Bing; Luo, Yuheng; Mao, Xiangbing; Zheng, Ping; Yu, Jie; Luo, Junqiu; He, Jun

    2017-01-01

    Skeletal muscle atrophy is a decrease in muscle mass that occurs when protein degradation exceeds protein synthesis. Leucine (Leu), an essential branched-chain amino acid in animal nutrition, regulates skeletal muscle protein metabolism. Two experiments were conducted to evaluate whether Leu could alleviate lipopolysaccharide (LPS)-induced skeletal muscle wasting by modulating skeletal muscle protein synthesis and degradation. A total of 24 rats were randomly allocated into three groups (n = 8): (1) non-challenged control; (2) LPS-challenged control; and (3) LPS +3.0% Leu. Rats were fed with control or Leu-supplemented (part of the casein was replaced with 3.0% Leu) diets throughout the trial and were injected intraperitoneally with sterile saline or LPS at days 6, 11, 16, and 21. On the morning of day 22, serum samples were collected and rats were then sacrificed for liver and muscle analysis. In vitro protein degradation, nuclear factor-κB (NF-κB) activity, and proteolytic enzyme activities of the muscles from immune-challenged rats were also measured. Our results showed that the LPS challenge resulted in not only enhanced serum interleukin-1 and liver C-reactive protein (CRP) concentrations but also decreased the average daily body weight gain and muscle fiber diameter. However, dietary Leu inclusion attenuated the increase in CRP level and the decrease in muscle fiber diameter. Importantly, the LPS challenge caused a significant elevation in the muscle proteolysis rate, but dietary Leu supplementation significantly blocked the muscle proteolysis. The mRNA expression of NF-κB, muscle atrophy F-box (MAFbx), and muscle ring finger 1 (MuRF1) was upregulated by the LPS challenge in gastrocnemius muscles, but was downregulated by Leu supplementation. Interestingly, when muscles from the LPS-challenged rats were incubated with Leu in vitro, proteasome-, calpain-, and cathepsin-L-dependent muscle proteolysis and NF-κB activity were decreased. Collectively, the

  7. Endothermic force generation in skinned cardiac muscle from rat.

    Science.gov (United States)

    Ranatunga, K W

    1999-08-01

    Isometric tension responses to rapid temperature jumps (T-jumps) of 2-6 degrees C were examined in skinned muscle fibre bundles isolated from papillary muscles of the rat heart. T-jumps were induced by an infra-red laser pulse (wave length 1.32 microm, pulse duration 0.2 ms) obtained from a Nd-YAG laser, which heated the fibres and bathing buffer solution in a 50 microl trough; the increased temperature by laser pulse was clamped at the high temperature by a Peltier system (see Ranatunga, 1996). In maximally Ca2+ -activated (pCa ca. 4.5) fibres, the relationship between tension and temperature was non-linear, the increase of active tension with temperature being more pronounced at lower temperatures (below ca. 20 degrees C). A T-jump at any temperature (range 3-35 degrees C) induced an initial step decrease of tension of variable amplitude (Phase 1), probably due to thermal expansion, and it was followed by a tension transient which resulted in a net rise of tension above the pre-T-jump level. The rate of net rise of tension (Phase 2b or endothermic force generation) was 7-10/s at ca. 12 degrees C and its Q10 was 6.3 (below 25 degrees C). In cases where the step decrease of tension in Phase 1 was prominent, an initial quick tension recovery phase (Phase 2a, 70-100/s at 12 degrees C) that did not contribute to a rise of tension above the pre-T-jump level, was also seen. This phase (Phase 2a) appeared to be similar to the quick tension recovery induced by a small length release and its rate increased with temperature with a Q10 of 1.8. In some cases where Phase 2a was present, a slower tension rise (Phase 3) was seen; its rate (ca. 5/s) was temperature-insensitive. The results show that the rate of endothermic force generation in cardiac fibres is clearly different from that of either fast-twitch or slow-twitch mammalian skeletal muscle fibres; implication of such fibre type-specific differences is discussed in relation to the difficulty in identifying the

  8. Effect of endurance training on glucose transport capacity and glucose transporter expression in rat skeletal muscle

    Energy Technology Data Exchange (ETDEWEB)

    Ploug, T.; Stallknecht, B.M.; Pedersen, O.; Kahn, B.B.; Ohkuwa, T.; Vinten, J.; Galbo, H. (Panum Institute, Copenhagen (Denmark))

    1990-12-01

    The effect of 10 wk endurance swim training on 3-O-methylglucose (3-MG) uptake (at 40 mM 3-MG) in skeletal muscle was studied in the perfused rat hindquarter. Training resulted in an increase of approximately 33% for maximum insulin-stimulated 3-MG transport in fast-twitch red fibers and an increase of approximately 33% for contraction-stimulated transport in slow-twitch red fibers compared with nonexercised sedentary muscle. A fully additive effect of insulin and contractions was observed both in trained and untrained muscle. Compared with transport in control rats subjected to an almost exhaustive single exercise session the day before experiment both maximum insulin- and contraction-stimulated transport rates were increased in all muscle types in trained rats. Accordingly, the increased glucose transport capacity in trained muscle was not due to a residual effect of the last training session. Half-times for reversal of contraction-induced glucose transport were similar in trained and untrained muscles. The concentrations of mRNA for GLUT-1 (the erythrocyte-brain-Hep G2 glucose transporter) and GLUT-4 (the adipocyte-muscle glucose transporter) were increased approximately twofold by training in fast-twitch red muscle fibers. In parallel to this, Western blot demonstrated a approximately 47% increase in GLUT-1 protein and a approximately 31% increase in GLUT-4 protein. This indicates that the increases in maximum velocity for 3-MG transport in trained muscle is due to an increased number of glucose transporters.

  9. Periurethral muscle-derived mononuclear cell injection improves urethral sphincter restoration in rats.

    Science.gov (United States)

    Turco, Marcelo Pitelli; de Souza, Alex Balduino; de Campos Sousa, Isida; Fratini, Paula; Veras, Mariana Matera; Rodrigues, Marcio Nogueira; de Bessa, José; Brolio, Marina Pandolphi; Leite, Katia Ramos Moreira; Bruschini, Homero; Srougi, Miguel; Miglino, Maria Angélica; Gomes, Cristiano Mendes

    2017-03-27

    Investigate the effect of a novel cell-based therapy with skeletal muscle-derived mononuclear cells (SMDMCs) in a rat model of stress urinary incontinence. Male Wistar-Kyoto rats' hind limb muscles were enzymatically dissociated, and SMDMCs were isolated without needing expansion. The cell population was characterized. Twenty female rats underwent urethrolysis. One week later, 10 rats received periurethral injection of 10(6) cells (SMDMC group), and 10 rats received saline injections (Saline group). Ten rats underwent sham surgery (Sham group). Four weeks after injection, animals were euthanized and the urethra was removed. The incorporation of SMDMCs in the female urethra was evaluated with fluorescence in situ hybridization for the detection of Y-chromosomes. Hematoxylin and eosin, Masson's trichrome staining, and immunohistochemistry for actin and myosin were performed. The muscle/connective tissue, actin and myosin ratios were calculated. Morphological evaluation of the urethral diameters and fractional areas of the lumen, mucosa, and muscular layer was performed. SMDMCs population was consistent with the presence of muscle cells, muscle satellite cells, perivascular cells, muscle progenitor cells, and endothelial cells. SMDMCs were incorporated into the urethra. A significant decrease in the muscle/connective tissue ratio was observed in the Saline group compared with the SMDMC and Sham groups. The proportions of actin and myosin were significantly decreased in the Saline group. No differences were observed in the morphometric parameters. SDMSC were incorporated into the rat urethra and promoted histological recovery of the damaged urethral sphincter, resulting in decreased connective tissue deposition and increased muscle content. © 2017 Wiley Periodicals, Inc.

  10. Increased cellular proliferation in rat skeletal muscle and tendon in response to exercise

    DEFF Research Database (Denmark)

    Skovgaard, Dorthe; Bayer, Monika L; Mackey, Abigail

    2010-01-01

    PURPOSE: The purpose of this study is to investigate exercise-induced cellular proliferation in rat skeletal muscle/tendon with the use of 3'-[F-18]fluoro-3'deoxythymidine (FLT) and to quantitatively study concomitant changes in the proliferation-associated factor, Ki67. PROCEDURES: Wistar rats (...

  11. Intercostal muscle motor behavior during tracheal occlusion conditioning in conscious rats

    Science.gov (United States)

    Jaiswal, Poonam B.

    2016-01-01

    A respiratory load compensation response is characterized by increases in activation of primary respiratory muscles and/or recruitment of accessory respiratory muscles. The contribution of the external intercostal (EI) muscles, which are a primary respiratory muscle group, during normal and loaded breathing remains poorly understood in conscious animals. Consciousness has a significant role on modulation of respiratory activity, as it is required for the integration of behavioral respiratory responses and voluntary control of breathing. Studies of respiratory load compensation have been predominantly focused in anesthetized animals, which make their comparison to conscious load compensation responses challenging. Using our established model of intrinsic transient tracheal occlusions (ITTO), our aim was to evaluate the motor behavior of EI muscles during normal and loaded breathing in conscious rats. We hypothesized that 1) conscious rats exposed to ITTO will recruit the EI muscles with an increased electromyogram (EMG) activation and 2) repeated ITTO for 10 days would potentiate the baseline EMG activity of this muscle in conscious rats. Our results demonstrate that conscious rats exposed to ITTO respond by recruiting the EI muscle with a significantly increased EMG activation. This response to occlusion remained consistent over the 10-day experimental period with little or no effect of repeated ITTO exposure on the baseline ∫EI EMG amplitude activity. The pattern of activation of the EI muscle in response to an ITTO is discussed in detail. The results from the present study demonstrate the importance of EI muscles during unloaded breathing and respiratory load compensation in conscious rats. PMID:26823339

  12. Enhancement of Skeletal Muscle in Aged Rats Following High-Intensity Stretch-Shortening Contraction Training.

    Science.gov (United States)

    Rader, Erik P; Naimo, Marshall A; Layner, Kayla N; Triscuit, Alyssa M; Chetlin, Robert D; Ensey, James; Baker, Brent A

    2016-08-03

    Exercise is the most accessible, efficacious, and multifactorial intervention to improve health and treat chronic disease. High-intensity resistance exercise, in particular, also maximizes skeletal muscle size and strength-outcomes crucial at advanced age. However, such training is capable of inducing muscle maladaptation when misapplied at old age. Therefore, characterization of parameters (e.g., mode and frequency) that foster adaptation is an active research area. To address this issue, we utilized a rodent model that allowed training at maximal intensity in terms of muscle activation and tested the hypothesis that muscles of old rats adapt to stretch-shortening contraction (SSC) training, provided the training frequency is sufficiently low. At termination of training, normalized muscle mass (i.e., muscle mass divided by tibia length) and muscle quality (isometric force divided by normalized muscle mass) were determined. For young rats, normalized muscle mass increased by ∼20% regardless of training frequency. No difference was observed for muscle quality values after 2 days versus 3 days per week training (0.65 ± 0.09 N/mg/mm vs. 0.59 ± 0.05 N/mg/mm, respectively). For old rats following 3 days per week training, normalized muscle mass was unaltered and muscle quality was 30% lower than young levels. Following 2 days per week training at old age, normalized muscle mass increased by 17% and muscle quality was restored to young levels. To investigate this enhanced response, oxidative stress was assessed by lipid peroxidation quantification. For young rats, lipid peroxidation levels were unaltered by training. With aging, baseline levels of lipid peroxidation increased by 1.5-fold. For old rats, only 2 days per week training decreased lipid peroxidation to levels indistinguishable from young values. These results imply that, appropriately scheduled high-intensity SSC training at old age is capable of restoring muscle to a younger phenotype in terms

  13. Effect of denervation or unweighting on GLUT-4 protein in rat soleus muscle

    Science.gov (United States)

    Henriksen, Erik J.; Rodnick, Kenneth J.; Mondon, Carl E.; James, David E.; Holloszy, John O.

    1991-01-01

    The study is intended to test the hypothesis that the decreased capacity for glucose transport in the denervated rat soleus and the increased capacity for glucose transport in the unweighted rat soleus are related to changes in the expression of the regulatable glucose transporter protein in skeletal muscle (GLUT-4). Results obtained indicate that altered GLUT-4 expression may be a major contributor to the changes in insulin-stimulated glucose transport that are observed with denervation and unweighting. It is concluded that muscle activity is an important factor in the regulation of the GLUT-4 expression in skeletal muscle.

  14. [Skeletal muscle mixed fiber tissue metabolism in rats after a flight on the Kosmos-690 biosatellite].

    Science.gov (United States)

    Gaevskaia, M S; Belitskaia, R A; Kolganova, N S; Kolchina, E V; Kurkina, L M

    1979-01-01

    On the R+O day the quadriceps muscle of rats showed a decrease in the content of T protein and an inhibition of LDH activity of sacroplasmatic proteins. These changes resulted from the combined affect of space flight factors and gamma-irradiation, and may be considered as a decline of compensatory synthetic processes responsible for the recovery of muscle proteins in weightlessness. Inhibition of the age-associated shift of the M:H ratio of LDH found on the R+25 day can be attributed to the inhibitory effect of gamma-irradiation. No change in the content of glycogen in the gastrocnemius muscle of flight rats was noted.

  15. Fatigue resistance of rat extraocular muscles does not depend on creatine kinase activity.

    Science.gov (United States)

    McMullen, Colleen A; Hayess, Katrin; Andrade, Francisco H

    2005-08-17

    Creatine kinase (CK) links phosphocreatine, an energy storage system, to cellular ATPases. CK activity serves as a temporal and spatial buffer for ATP content, particularly in fast-twitch skeletal muscles. The extraocular muscles are notoriously fast and active, suggesting the need for efficient ATP buffering. This study tested the hypotheses that (1) CK isoform expression and activity in rat extraocular muscles would be higher, and (2) the resistance of these muscles to fatigue would depend on CK activity. We found that mRNA and protein levels for cytosolic and mitochondrial CK isoforms were lower in the extraocular muscles than in extensor digitorum longus (EDL). Total CK activity was correspondingly decreased in the extraocular muscles. Moreover, cytoskeletal components of the sarcomeric M line, where a fraction of CK activity is found, were downregulated in the extraocular muscles as was shown by immunocytochemistry and western blotting. CK inhibition significantly accelerated the development of fatigue in EDL muscle bundles, but had no major effect on the extraocular muscles. Searching for alternative ATP buffers that could compensate for the relative lack of CK in extraocular muscles, we determined that mRNAs for two adenylate kinase (AK) isoforms were expressed at higher levels in these muscles. Total AK activity was similar in EDL and extraocular muscles. These data indicate that the characteristic fatigue resistance of the extraocular muscles does not depend on CK activity.

  16. Fatigue resistance of rat extraocular muscles does not depend on creatine kinase activity

    Directory of Open Access Journals (Sweden)

    Hayeß Katrin

    2005-08-01

    Full Text Available Abstract Background Creatine kinase (CK links phosphocreatine, an energy storage system, to cellular ATPases. CK activity serves as a temporal and spatial buffer for ATP content, particularly in fast-twitch skeletal muscles. The extraocular muscles are notoriously fast and active, suggesting the need for efficient ATP buffering. This study tested the hypotheses that (1 CK isoform expression and activity in rat extraocular muscles would be higher, and (2 the resistance of these muscles to fatigue would depend on CK activity. Results We found that mRNA and protein levels for cytosolic and mitochondrial CK isoforms were lower in the extraocular muscles than in extensor digitorum longus (EDL. Total CK activity was correspondingly decreased in the extraocular muscles. Moreover, cytoskeletal components of the sarcomeric M line, where a fraction of CK activity is found, were downregulated in the extraocular muscles as was shown by immunocytochemistry and western blotting. CK inhibition significantly accelerated the development of fatigue in EDL muscle bundles, but had no major effect on the extraocular muscles. Searching for alternative ATP buffers that could compensate for the relative lack of CK in extraocular muscles, we determined that mRNAs for two adenylate kinase (AK isoforms were expressed at higher levels in these muscles. Total AK activity was similar in EDL and extraocular muscles. Conclusion These data indicate that the characteristic fatigue resistance of the extraocular muscles does not depend on CK activity.

  17. Muscle pain induced by static contraction in rats is modulated by peripheral inflammatory mechanisms.

    Science.gov (United States)

    Santos, Diogo Francisco da Silva Dos; Melo Aquino, Bruna de; Jorge, Carolina Ocanha; Azambuja, Graciana de; Schiavuzzo, Jalile Garcia; Krimon, Suzy; Neves, Juliana Dos Santos; Parada, Carlos Amilcar; Oliveira-Fusaro, Maria Claudia Gonçalves

    2017-09-01

    Muscle pain is an important health issue and frequently related to static force exertion. The aim of this study is to evaluate whether peripheral inflammatory mechanisms are involved with static contraction-induced muscle pain in rats. To this end, we developed a model of muscle pain induced by static contraction performed by applying electrical pulses through electrodes inserted into muscle. We also evaluated the involvement of neutrophil migration, bradykinin, sympathetic amines and prostanoids. A single session of sustained static contraction of gastrocnemius muscle induced acute mechanical muscle hyperalgesia without affecting locomotor activity and with no evidence of structural damage in muscle tissue. Static contraction increased levels of creatine kinase but not lactate dehydrogenase, and induced neutrophil migration. Dexamethasone (glucocorticoid anti-inflammatory agent), DALBK (bradykinin B1 antagonist), Atenolol (β1 adrenoceptor antagonist), ICI 118,551 (β2 adrenoceptor antagonist), indomethacin (cyclooxygenase inhibitor), and fucoidan (non-specific selectin inhibitor) all reduced static contraction-induced muscle hyperalgesia; however, the bradykinin B2 antagonist, bradyzide, did not have an effect on static contraction-induced muscle hyperalgesia. Furthermore, an increased hyperalgesic response was observed when the selective bradykinin B1 agonist des-Arg(9)-bradykinin was injected into the previously stimulated muscle. Together, these findings demonstrate that static contraction induced mechanical muscle hyperalgesia in gastrocnemius muscle of rats is modulated through peripheral inflammatory mechanisms that are dependent on neutrophil migration, bradykinin, sympathetic amines and prostanoids. Considering the clinical relevance of muscle pain, we propose the present model of static contraction-induced mechanical muscle hyperalgesia as a useful tool for the study of mechanisms underlying static contraction-induced muscle pain. Copyright © 2017 IBRO

  18. Noninvasive Cu-64-ATSM and PET/CT Assessment of Hypoxia in Rat Skeletal Muscles and Tendons During Muscle Contractions

    DEFF Research Database (Denmark)

    Skovgaard, D.; Kjaer, M.; Madsen, J.;

    2009-01-01

    expression of 2 hypoxia-related genes, hypoxia-inducible factor 1 alpha (HIF1 alpha) and carbonic anhydrase III (CAIII). Methods: Two groups of Wistar rats performed 1-leg contractions of the calf muscle by electrostimulation of the sciatic nerve. After 10 min of muscle contractions, Cu-64-ATSM was injected...... and contractions were continued for 20 min. PET/CT of both hind limbs was performed immediately and 1 h after the contractions. The exercise group (n = 8) performed only muscle contractions as described, whereas the other group, exercise plus cuff (n = 8), in addition underwent cuff-induced hypoxia during...... the first PET/CT scan. Standardized uptake values (SUVs) were calculated for the Achilles tendons and triceps surae muscles and were correlated to gene expression of HIF1 alpha and CAIII using real-time polymerase chain reaction. Results: Immediately after the contractions, uptake of Cu-64-ATSM...

  19. SPRINT-INTERVAL TRAINING INDUCES HEAT SHOCK PROTEIN 72 IN RAT SKELETAL MUSCLES

    Directory of Open Access Journals (Sweden)

    Yuji Ogura

    2006-06-01

    Full Text Available Previous studies have demonstrated that endurance exercise training increases the level of heat shock proteins (HSPs in skeletal muscles. However, little attention has been drawn to the effects of high intensity-short duration exercise, or sprint- interval training (SIT on HSP72 level in rat skeletal muscles. This study performed to test the hypothesis that the SIT would induce the HSP72 in fast and slow skeletal muscles of rats. Young male Wistar rats (8 weeks old were randomly assigned to a control (CON or a SIT group (n = 8/group. Animals in the SIT group were trained (1 min/sprint, 6~10 sets/day and 5~6 days/week on a treadmill for 9 weeks. After the training period, HSP72 levels in the plantaris (fast and soleus (slow muscles were analyzed by Western blotting method. Enzyme activities (hexokinase, phosphofructokinase and citrate synthase and histochemical properties (muscle fiber type compositions and cross sectional area in both muscles were also determined. The SIT resulted in significantly (p < 0.05 higher levels of HSP72 in both the plantaris and soleus muscles compared to the CON group, with the plantaris producing a greater HSP72 increase than the soleus (plantaris; 550 ± 116%, soleus; 26 ± 8%, p < 0.05. Further, there were bioenergetic improvements, fast-to-slow shift of muscle fiber composition and hypertrophy in the type IIA fiber only in the plantaris muscle. These findings indicate that the SIT program increases HSP72 level of the rat hindlimb muscles, and the SIT-induced accumulation of HSP72 differs between fast and slow muscles

  20. THE ROLE OF SATELLITE CELLS IN CRUSH INJURY OF RAT SKELETON MUSCLE

    Directory of Open Access Journals (Sweden)

    DilekBURUKOĞLU

    2013-02-01

    Full Text Available The crush type of injury in rat skeletal muscle is often used in tissue degeneration and regeneration. After crush injury muscle tissue begins to regenerate. In this process, it is accepted that satellite cells play an important role which are very sensitive to muscle injury. The aim of this microscopic study was to examine role of satellite cells in muscle regeneration in crush injury. This research was done the department of Histology&Embryology in Eskişehir Osmangazi University in 2008. Ethic approval of this study has been received. During the study, the whole essential and ethics conditionshave been done. In the study 36 Spraque-Dawley rats were used. The rats were separated into 5 groups as test and control groups. Crush type of injury has been applied on muscles of right hind extremitiesof testing group rats by applying 3.5 kg of weight for 6 hours. In according to testing periods rats were anaesthetized intraperitoneally with ketamine 30mg/kg + xylazine 10mg/kg and sacrificied 3, 7, 14 and 21-day intervals. After crush injury, increased satellite cells were particularly observed on day 7. Alsosignificant increased of satellite cells and regenerated myofibrils were detected on day 14. However, satellite cells were seen on day-21 were similar to control group. In crush injuries, number of satellitecells were markedly increased and actively involved into regeneration process of the skeleton muscle.

  1. Fatiguing stimulation of one skeletal muscle triggers heat shock protein activation in several rat organs: the role of muscle innervation.

    Science.gov (United States)

    Jammes, Yves; Steinberg, Jean Guillaume; By, Youlet; Brerro-Saby, Christelle; Condo, Jocelyne; Olivier, Marine; Guieu, Regis; Delliaux, Stephane

    2012-11-15

    We hypothesised that activation of muscle afferents by fatigue triggers a widespread activation of heat shock proteins (HSPs) in resting muscles and different organs. In anaesthetised rats, HSP25 and HSP70 levels were determined in both tibialis anterior (TA) and extensor digitorum longus (EDL) muscles and in the diaphragm, kidney and brain by ELISA, which mostly identifies phosphorylated HSP, and western blotting. One TA muscle was electrically stimulated and tissues were sampled 10 or 60 min after the stimulation had ended. The nerve supply to the stimulated TA or its counterpart in the contralateral limb was left intact or suppressed. In control rats, no muscle stimulation was performed and tissues were sampled at the same time points (10 or 60 min). After TA stimulation, ELISA showed an increased HSP25 content in the contralateral TA, EDL and diaphragm at 10 min but not at 60 min, and HSP70 increased in all sampled tissues at 60 min. Western blotting did not show any changes in HSP25 and HSP70 at 10 min, while at 60 min HSP25 increased in all sampled tissues except the brain and HSP70 was elevated in all tissues. Denervation of the contralateral non-stimulated limb suppressed HSP changes in TA and after denervation of the stimulated TA the widespread activation of HSPs in other organs was absent. Our data suggest that fatigue-induced activation of skeletal muscle afferents triggers an early increase in phosphorylated HSP25 in muscles and a delayed elevation of non-phosphorylated HSP25 and HSP70 in skeletal and respiratory muscles, kidney and brain.

  2. [Contractile properties of skeletal muscles of rats after flight on "Kosmos-1887"].

    Science.gov (United States)

    Oganov, V S; Skuratova, S A; Murashko, L M

    1991-01-01

    Contractile properties of skeletal muscles of rats were investigated using glycerinated muscle preparations that were obtained from Cosmos-1887 animals flown for 13 days (plus 2 days on the ground) and from rats that remained hypokinetic for 13 days on the ground. In the flow rats, the absolute mass of postural muscles remained unchanged while their relative mass increased; this may be attributed to their enhanced hydration which developed during the first 2 days after landing. Strength losses of the postural muscles were less significant than after previous flights. Comparison of the Cosmos-1887 and hypokinesia control data has shown that even 2-day exposure to 1 G after 13-day flight can modify drastically flight-induced changes.

  3. Effect of Cerium on Cardiac Muscle of Rat and Guinea Pig

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    The effect of Ce3+ on cardiac muscle of rat and guinea pig was studied. In vitro, 0.05 mmol.L-1 solution of Ce3+ inhibited the contraction of guinea pig atria. The change of action potential duration(APD) of guinea pig papillary muscle exposed to 0.4 mmol·L-1 Ce3+ was significant, and those exposed to 0.1 and 0.2 mmol·L-1 Ce3+ were not significant. In vivo, compared with the control group, the APD for rat cardiac muscle after long-term feed on Ce3+ was significantly delayed in high dose, and that was not significantly delayed in low dose. The results suggest that Ce3+ with long-term high dose intake might affect the influx of Ca2+, Na+ and outflow of K+ for rat cardiac muscle.

  4. Optimizing hyaluronidase dose and plasmid DNA delivery greatly improves gene electrotransfer efficiency in rat skeletal muscle

    DEFF Research Database (Denmark)

    Åkerström, Thorbjörn; Vedel, Kenneth; Needham Andersen, Josefine;

    2015-01-01

    delivery across the muscle by increasing the number of plasmid DNA injections further enhanced transfection efficiency whereas increasing plasmid dose from 0.2 to 1.6. μg/g b.w. or vehicle volume had no effect. The optimized protocol resulted in ~80% (CI95%: 79-84%) transfected muscle fibers......Transfection of rat skeletal muscle in vivo is a widely used research model. However, gene electrotransfer protocols have been developed for mice and yield variable results in rats. We investigated whether changes in hyaluronidase pre-treatment and plasmid DNA delivery can improve transfection...... with a homogenous distribution. We also show that transfection was stable over five weeks of regular exercise or inactivity. Our findings show that species-specific plasmid DNA delivery and hyaluronidase pre-treatment greatly improves transfection efficiency in rat skeletal muscle....

  5. Transcriptional profiling of rat skeletal muscle hypertrophy under restriction of blood flow.

    Science.gov (United States)

    Xu, Shouyu; Liu, Xueyun; Chen, Zhenhuang; Li, Gaoquan; Chen, Qin; Zhou, Guoqing; Ma, Ruijie; Yao, Xinmiao; Huang, Xiao

    2016-12-15

    Blood flow restriction (BFR) under low-intensity resistance training (LIRT) can produce similar effects upon muscles to that of high-intensity resistance training (HIRT) while overcoming many of the restrictions to HIRT that occurs in a clinical setting. However, the potential molecular mechanisms of BFR induced muscle hypertrophy remain largely unknown. Here, using a BFR rat model, we aim to better elucidate the mechanisms regulating muscle hypertrophy as induced by BFR and reveal possible clinical therapeutic targets for atrophy cases. We performed genome wide screening with microarray analysis to identify unique differentially expressed genes during rat muscle hypertrophy. We then successfully separated the differentially expressed genes from BRF treated soleus samples by comparing the Affymetrix rat Genome U34 2.0 array with the control. Using qRT-PCR and immunohistochemistry (IHC) we also analyzed other related differentially expressed genes. Results suggested that muscle hypertrophy induced by BFR is essentially regulated by the rate of protein turnover. Specifically, PI3K/AKT and MAPK pathways act as positive regulators in controlling protein synthesis where ubiquitin-proteasome acts as a negative regulator. This represents the first general genome wide level investigation of the gene expression profile in the rat soleus after BFR treatment. This may aid our understanding of the molecular mechanisms regulating and controlling muscle hypertrophy and provide support to the BFR strategies aiming to prevent muscle atrophy in a clinical setting. Copyright © 2016 Elsevier B.V. All rights reserved.

  6. Effect of hypnosis on masseter EMG recorded during the 'resting' and a slightly open jaw posture.

    Science.gov (United States)

    Al-Enaizan, N; Davey, K J; Lyons, M F; Cadden, S W

    2015-11-01

    The aim of this experimental study was to determine whether minimal levels of electromyographic activity in the masseter muscle are altered when individuals are in a verified hypnotic state. Experiments were performed on 17 volunteer subjects (8 male, 9 female) all of whom gave informed consent. The subjects were dentate and had no symptoms of pain or masticatory dysfunction. Surface electromyograms (EMGs) were made from the masseter muscles and quantified by integration following full-wave rectification and averaging. The EMGs were obtained (i) with the mandible in 'resting' posture; (ii) with the mandible voluntarily lowered (but with the lips closed); (iii) during maximum voluntary clenching (MVC). The first two recordings were made before, during and after the subjects were in a hypnotic state. Susceptibility to hypnosis was assessed with Spiegel's eye-roll test, and the existence of the hypnotic state was verified by changes in ventilatory pattern. On average, EMG levels expressed as percentages of MVC were less: (i) when the jaw was deliberately lowered as opposed to being in the postural position: (ii) during hypnosis compared with during the pre- and post-hypnotic periods. However, analysis of variance followed by post hoc tests with multiple comparison corrections (Bonferroni) revealed that only the differences between the level during hypnosis and those before and after hypnosis were statistically significant (P hypnosis, it appears that part of that EMG is of biological origin.

  7. Characteristics of Tetanic Force Produced by the Sternomastoid Muscle of the Rat

    Directory of Open Access Journals (Sweden)

    Stanislaw Sobotka

    2010-01-01

    Full Text Available The sternomastoid (SM muscle plays an important role in supporting breathing. It also has unique anatomical advantages that allow its wide use in head and neck tissue reconstruction and muscle reinnervation. However, little is known about its contractile properties. The experiments were run on rats and designed to determine in vivo the relationship between muscle force (active muscle contraction to electrical stimulation with passive tension (passive force changing muscle length and two parameters (intensity and frequency of electrical stimulation. The threshold current for initiating noticeable muscle contraction was 0.03 mA. Maximal muscle force (0.94 N was produced by using moderate muscle length/tension (28 mm/0.08 N, 0.2 mA stimulation current, and 150 Hz stimulation frequency. These data are important not only to better understand the contractile properties of the rat SM muscle, but also to provide normative values which are critical to reliably assess the extent of functional recovery following muscle reinnervation.

  8. Force Characteristics of the Rat Sternomastoid Muscle Reinnervated with End-to-End Nerve Repair

    Directory of Open Access Journals (Sweden)

    Stanislaw Sobotka

    2011-01-01

    Full Text Available The goal of this study was to establish force data for the rat sternomastoid (SM muscle after reinnervation with nerve end-to-end anastomosis (EEA, which could be used as a baseline for evaluating the efficacy of new reinnervation techniques. The SM muscle on one side was paralyzed by transecting its nerve and then EEA was performed at different time points: immediate EEA, 1-month and 3-month delay EEA. At the end of 3-month recovery period, the magnitude of functional recovery of the reinnervated SM muscle was evaluated by measuring muscle force and comparing with the force of the contralateral control muscle. Our results demonstrated that the immediately reinnervated SM produced approximately 60% of the maximal tetanic force of the control. The SM with delayed nerve repair yielded approximately 40% of the maximal force. Suboptimal recovery of muscle force after EEA demonstrates the importance of developing alternative surgical techniques to treat muscle paralysis.

  9. Skeletal muscle and hormonal adaptation to physical training in the rat

    DEFF Research Database (Denmark)

    Henriksson, J; Svedenhag, J; Richter, Erik

    1985-01-01

    The main purpose of the present study was to test the hypothesis that adrenergic stimulation of muscle fibres during exercise is a major stimulus for the training-induced enhancement of skeletal muscle respiratory capacity. Therefore, Sprague-Dawley rats either underwent bilateral surgical ablation...... of the adrenal medulla or were sham-operated. Furthermore, unilateral surgical extirpation of the lumbar sympathetic chain was performed. Half of the rats were then trained for 12 weeks by swimming (up to 5.5 h X day-1, 4 days X week-1) and the remaining rats were sedentary controls. In the gastrocnemius muscle......, training significantly increased the mitochondrial enzymes citrate synthase, succinate dehydrogenase, cytochrome c oxidase, and 3-hydroxyacyl-CoA dehydrogenase. In sham-operated rats, the increases were 40%, 43%, 66%, and 25%, respectively, in legs with intact sympathetic innervation. The training...

  10. Electrical Stimulation of Denervated Rat Skeletal Muscle Ameliorates Bone Fragility and Muscle Loss in Early-Stage Disuse Musculoskeletal Atrophy.

    Science.gov (United States)

    Tamaki, Hiroyuki; Yotani, Kengo; Ogita, Futoshi; Hayao, Keishi; Nakagawa, Kouki; Sugawara, Kazuhiro; Kirimoto, Hikari; Onishi, Hideaki; Kasuga, Norikatsu; Yamamoto, Noriaki

    2017-04-01

    We tested whether daily muscle electrical stimulation (ES) can ameliorate the decrease in cortical bone strength as well as muscle and bone geometric and material properties in the early stages of disuse musculoskeletal atrophy. 7-week-old male F344 rats were randomly divided into three groups: age-matched control group (Cont); a sciatic denervation group (DN); and a DN + direct electrical stimulation group (DN + ES). Denervated tibialis anterior (TA) muscle in the DN + ES group received ES with 16 mA at 10 Hz for 30 min/day, 6 days/week. Micro CT, the three-point bending test, and immunohistochemistry were used to characterize cortical bone mechanical, structural, and material properties of tibiae. TA muscle in the DN + ES group showed significant improvement in muscle mass and myofiber cross-sectional area relative to the DN group. Maximal load and stiffness of tibiae, bone mineral density estimated by micro CT, and immunoreactivity of DMP1 in the cortical bone tissue were also significantly greater in the DN + ES group than in the DN group. These results suggest that daily ES-induced muscle contraction treatment reduced the decrease in muscle mass and cortical bone strength in early-stage disuse musculoskeletal atrophy and is associated with a beneficial effect on material properties such as mineralization of cortical bone tissue.

  11. Induction of Muscle Hypertrophy in Rats through Low Intensity Eccentric Contraction.

    Science.gov (United States)

    Tsumiyama, Wakako; Oki, Sadaaki; Takamiya, Naomi; Umei, Namiko; Shimizu, Michele Eisemann; Ono, Takeya; Otsuka, Akira

    2014-10-01

    [Purpose] The purpose of this study was to examine whether a low intensity exercise using an eccentric contraction would result in skeletal muscle hypertrophy in rats. [Subjects and Methods] Eighteen female Wistar rats were used in this study. The rats were randomly divided into three groups. The control group performed no exercise. The level group ran on a treadmill on a 0° incline. The downhill group ran on a treadmill on a -16° incline. The two exercise groups ran on a treadmill at 16 m/min for 90 minutes, once every three days for a total of twenty sessions. [Results] The muscle wet weights, the relative weight ratios, and the muscle fiber cross-section minor axes of the downhill group were significantly larger than those of the control and level groups. There were no differences in the muscle wet weights, the relative weight ratios, and the muscle fiber cross-section minor axes between the control group and the level group. [Conclusion] The stimulation from the low intensity eccentric contraction may have produced enough mechanical stress to induce muscle hypertrophy without the over-stressing that might have produced muscle fiber damage. These results indicate that this technique may be an effective method of inducing hypertrophy in skeletal muscle.

  12. Architectural and morphological assessment of rat abdominal wall muscles: comparison for use as a human model.

    Science.gov (United States)

    Brown, Stephen H M; Banuelos, Karina; Ward, Samuel R; Lieber, Richard L

    2010-09-01

    The abdominal wall is a composite of muscles that are important for the mechanical stability of the spine and pelvis. Tremendous clinical attention is given to these muscles, yet little is known about how they function in isolation or how they interact with one another. Given the morphological, vascular, and innervation complexities associated with these muscles and their proximity to the internal organs, an appropriate animal model is important for understanding their physiological and mechanical significance during function. To determine the extent to which the rat abdominal wall resembles that of human, 10 adult male Sprague-Dawley rats were killed and formalin-fixed for architectural and morphological analyses of the four abdominal wall muscles (rectus abdominis, external oblique, internal oblique, and transversus abdominis). Physiological cross-sectional areas and optimal fascicle lengths demonstrated a pattern that was similar to human abdominal wall muscles. In addition, sarcomere lengths measured in the neutral spine posture were similar to human in their relation to optimal sarcomere length. These data indicate that the force-generating and length change capabilities of these muscles, relative to one another, are similar in rat and human. Finally, the fiber lines of action of each abdominal muscle were similar to human over most of the abdominal wall. The main exception was in the lower abdominal region (inferior to the pelvic crest), where the external oblique becomes aponeurotic in human but continues as muscle fibers into its pelvic insertion in the rat. We conclude that, based on the morphology and architecture of the abdominal wall muscles, the adult male Sprague-Dawley rat is a good candidate for a model representation of human, particularly in the middle and upper abdominal wall regions.

  13. Localized infusion of IGF-I results in skeletal muscle hypertrophy in rats

    Science.gov (United States)

    Adams, G. R.; McCue, S. A.

    1998-01-01

    Insulin-like growth factor I (IGF-I) peptide levels have been shown to increase in overloaded skeletal muscles (G. R. Adams and F. Haddad. J. Appl. Physiol. 81: 2509-2516, 1996). In that study, the increase in IGF-I was found to precede measurable increases in muscle protein and was correlated with an increase in muscle DNA content. The present study was undertaken to test the hypothesis that direct IGF-I infusion would result in an increase in muscle DNA as well as in various measurements of muscle size. Either 0.9% saline or nonsystemic doses of IGF-I were infused directly into a non-weight-bearing muscle of rats, the tibialis anterior (TA), via a fenestrated catheter attached to a subcutaneous miniosmotic pump. Saline infusion had no effect on the mass, protein content, or DNA content of TA muscles. Local IGF-I infusion had no effect on body or heart weight. The absolute weight of the infused TA muscles was approximately 9% greater (P muscles. IGF-I infusion resulted in significant increases in the total protein and DNA content of TA muscles (P hypertrophied TA was similar to that of the contralateral muscles. These results suggest that IGF-I may be acting to directly stimulate processes such as protein synthesis and satellite cell proliferation, which result in skeletal muscle hypertrophy.

  14. Localized infusion of IGF-I results in skeletal muscle hypertrophy in rats

    Science.gov (United States)

    Adams, G. R.; McCue, S. A.

    1998-01-01

    Insulin-like growth factor I (IGF-I) peptide levels have been shown to increase in overloaded skeletal muscles (G. R. Adams and F. Haddad. J. Appl. Physiol. 81: 2509-2516, 1996). In that study, the increase in IGF-I was found to precede measurable increases in muscle protein and was correlated with an increase in muscle DNA content. The present study was undertaken to test the hypothesis that direct IGF-I infusion would result in an increase in muscle DNA as well as in various measurements of muscle size. Either 0.9% saline or nonsystemic doses of IGF-I were infused directly into a non-weight-bearing muscle of rats, the tibialis anterior (TA), via a fenestrated catheter attached to a subcutaneous miniosmotic pump. Saline infusion had no effect on the mass, protein content, or DNA content of TA muscles. Local IGF-I infusion had no effect on body or heart weight. The absolute weight of the infused TA muscles was approximately 9% greater (P muscles. IGF-I infusion resulted in significant increases in the total protein and DNA content of TA muscles (P hypertrophied TA was similar to that of the contralateral muscles. These results suggest that IGF-I may be acting to directly stimulate processes such as protein synthesis and satellite cell proliferation, which result in skeletal muscle hypertrophy.

  15. Influence of exercise training on the oxidative capacity of rat abdominal muscles

    Science.gov (United States)

    Uribe, J. M.; Stump, C. S.; Tipton, C. M.; Fregosi, R. F.

    1992-01-01

    Our purpose was to determine if endurance exercise training would increase the oxidative capacity of the abdominal expiratory muscles of the rat. Accordingly, 9 male rats were subjected to an endurance training protocol (1 h/day, 6 days/week, 9 weeks) and 9 litter-mates served as controls. Citrate synthase (CS) activity was used as an index of oxidative capacity, and was determined in the following muscles: soleus, plantaris, costal diaphragm, crural diaphragm, and in all four abdominal muscles: rectus abdominis, transversus abdominis, external oblique, and internal oblique. Compared to their non-trained litter-mates, the trained rats had higher peak whole body oxygen consumption rates (+ 16%) and CS activities in plantaris (+34%) and soleus (+36%) muscles. Thus, the training program caused substantial systemic and locomotor muscle adaptations. The CS activity of costal diaphragm was 20% greater in the trained animals, but no difference was observed in crural diaphragm. The CS activity in the abdominal muscles was less than one-half of that in locomotor and diaphragm muscles, and there were no significant changes with training except in the rectus abdominis where a 26% increase was observed. The increase in rectus abdominis CS activity may reflect its role in postural support and/or locomotion, as none of the primary expiratory pumping muscles adapted to the training protocol. The relatively low levels of CS activity in the abdominal muscles suggests that they are not recruited frequently at rest, and the lack of an increase with training indicates that these muscles do not contribute significantly to the increased ventilatory activity accompanying exercise in the rat.

  16. Glycogen stability and glycogen phosphorylase activities in isolated skeletal muscles from rat and toad.

    Science.gov (United States)

    Goodman, C A; Stephenson, G M

    2000-01-01

    There is increasing evidence that endogenous glycogen depletion may affect excitation-contraction (E-C) coupling events in vertebrate skeletal muscle. One approach employed in physiological investigations of E-C coupling involves the use of mechanically skinned, single fibre preparations obtained from tissues stored under paraffin oil, at room temperature (RT: 20-24 degrees C) and 4 degrees C for several hours. In the present study, we examined the effect of these storage conditions on the glycogen content in three muscles frequently used in research on E-C coupling: rat extensor digitorum longus (EDL) and soleus (SOL) and toad iliofibularis (IF). Glycogen content was determined fluorometrically in homogenates prepared from whole muscles, stored under paraffin oil for up to 6 h at RT or 4 degrees C. Control muscles and muscles stored for 0.5 and 6 h were also analysed for total phosphorylase (Phos(total)) and phosphorylase a (Phos a) activities. No significant change was observed in the glycogen content of EDL and SOL muscles stored at RT for 0.5 h. In rat muscles stored at RT for longer than 0.5 h, the glycogen content decreased to 67.6% (EDL) and 78.7% (SOL) of controls after 3 h and 25.3% (EDL) and 37.4% (SOL) after 6 h. Rat muscles stored at 4 degrees C retained 79.0% (EDL) and 92.5% (SOL) of glycogen after 3 h and 75.2% (EDL) and 61.1% (SOL) after 6 h. The glycogen content of IF muscles stored at RT or 4 degrees C for 6 h was not significantly different from controls. Phos(total) was unchanged in all muscles over the 6 h period, at both temperatures. Phos a was also unchanged in the toad IF muscles, but in rat muscles it decreased rapidly, particularly in EDL (4.1-fold after 0.5 h at RT). Taken together these results indicate that storage under paraffin oil for up to 6 h at RT or 4 degrees C is accompanied by minimal glycogen loss in toad IF muscles and by a time- and temperature-dependent glycogen loss in EDL and SOL muscles of the rat.

  17. Vitamin E levels in soleus muscles of experimentally induced hyperthyroid rats differ consequent to feeding of edible oils.

    Science.gov (United States)

    Merican, Z; Suboh, B; Marzuki, A; Khalid, B A

    1999-12-01

    It has been shown that lipid peroxidation product levels in the soleus muscles of rats fed palm olein were lower than in the soleus muscles of rats fed soya bean oil. A study was carried out to test our hypothesis that the lower level of lipid peroxidation products in the soleus muscle of palm olein-fed rats is due, at least partly, to the higher amount of vitamin E in their soleus muscles. Experimentally induced hyperthyroid rats were fed either ground rat chow or ground rat chow mixed with palm olein oil or soya bean oil for a period of 8 weeks. Euthyroid rats fed ground rat chow for a similar period served as controls. At the end of the 8-week period, the rats were sacrificed and the α-tocopherol and tocotrienol levels in their soleus muscles were measured using high pressure liquid chromatography. It was found that the levels of α-tocopherol (23.682 ± 0.363), α-tocotrienol (1.974 ± 0.040) and γ-tocotrienol (1.418 ± 0.054) in μg/g tissue wet weight in the soleus muscles of hyperthyroid rats fed palm olein oil were statistically significantly higher than those found in the soleus muscles of hyperthyroid rats fed soya bean oil, which were 14.299 ± 0.378, 0.053 ± 0.053 and 0.184 ± 0.120μg/g tissue wet weight, respectively. The result shows that the increased level of a-tocopherol and tocotrienols found in the soleus muscles of hyperthyroid rats fed palm olein oil is responsible, at least partly, for the lower amount of lipid peroxidation products in these muscles compared with the soleus muscles of hyperthyroid rats fed soya bean oil in our earlier study.

  18. Effect of age on fatty infiltration of supraspinatus muscle after experimental tendon release in rats

    Directory of Open Access Journals (Sweden)

    Farshad Mazda

    2011-12-01

    Full Text Available Abstract Background Rotator cuff tendon tear is a leading cause for atrophy, fibrosis and fatty infiltration of the rotator cuff muscles. The pathophysiology of fatty muscle infiltration is not well understood. An animal model suited to study cellular and molecular mechanisms would therefore be desirable. While a rat model has been established for chronic rotator cuff tendon pathology, sufficient and easily identifiable fatty infiltration of the muscle has not yet been shown in rats. As younger animals regenerate better, we hypothesized that the absence of a sufficient amount of fatty infiltration in previous experiments was due to the selection of young animals and that older animals would exhibit higher amounts of fatty infiltration after tendon tear. Findings The supraspinatus tendon was released using tenotomy in 3 young (6 weeks old and in 3 aged (24 months old Sprague Dawley rats (group I and II. Another 3 aged (24 months old rats underwent sham surgery and served as a control group (group III. In group I and II retraction of the musculotendinous unit was allowed for 6 weeks. All animals were sacrificed 6 weeks after surgery and the supraspinatus muscles were harvested. Each sample was examined for fatty infiltration of the muscle by histological methods and micro-CT. In histology, fat cells were counted with a 10-fold magnification in 6 fields of view twice. An adjusted measurement setup was developed for the use of micro-CT to quantify the absorption coefficient of the muscle as a reciprocal indicator for fatty infiltration, based on the established procedure for quantification of fatty infiltration on CT in humans. Tenotomy resulted in an insignificant increase of fat cells in histological sections in both, aged and young rats. Micro-CT was able to quantify small differences in the absorption coefficients of muscle samples; the absorption coefficient was 8.1% ± 11.3% lower in retracted muscles (group I and II compared with the control

  19. [Effects of antioxidant on reduction of hindlimb muscle atrophy induced by cisplatin in rats].

    Science.gov (United States)

    Kim, Jin il; Choe, Myoung-Ae

    2014-08-01

    The purpose of this study was to examine the effects of Cu/Zn SOD on reduction of hindlimb muscular atrophy induced by cisplatin in rats. Forty-two rats were assigned to three groups; control group, Cisplatin (CDDP) group and cisplatin with Cu/Zn SOD (CDDP-SOD) group. At day 35 hindlimb muscles were dissected. Food intake, activity, withdrawal threshold, muscle weight, and Type I, II fiber cross-sectional area (CSA) of dissected muscles were measured. Relative SOD activity and expression of MHC and phosphorylated Akt, ERK were measured after dissection. Muscle weight and Type I, II fiber CSA of hindlimb muscles in the CDDP group were significantly less than the control group. Muscle weight and Type I, II fiber CSA of hindlimb muscles, food intake, activity, and withdrawal thresholds of the CDDP-SOD group were significantly greater than the CDDP group. There were no significant differences in relative SOD activities of hindlimb muscles between the CDDP-SOD and CDDP groups. MHC expression and phosphorylated Akt, ERK of hindlimb muscles in the CDDP-SOD group were significantly greater than the CDDP group. Cu/Zn SOD attenuates hindlimb muscular atrophy induced by cisplatin through increased food intake and activity. Increment of phosphorylated Akt, ERK may relate to attenuation of hindlimb muscular atrophy.

  20. Mitochondria-targeted antioxidant preserves contractile properties and mitochondrial function of skeletal muscle in aged rats.

    Science.gov (United States)

    Javadov, Sabzali; Jang, Sehwan; Rodriguez-Reyes, Natividad; Rodriguez-Zayas, Ana E; Soto Hernandez, Jessica; Krainz, Tanja; Wipf, Peter; Frontera, Walter

    2015-11-24

    Mitochondrial dysfunction plays a central role in the pathogenesis of sarcopenia associated with a loss of mass and activity of skeletal muscle. In addition to energy deprivation, increased mitochondrial ROS damage proteins and lipids in aged skeletal muscle. Therefore, prevention of mitochondrial ROS is important for potential therapeutic strategies to delay sarcopenia. This study elucidates the pharmacological efficiency of the new developed mitochondria-targeted ROS and electron scavenger, XJB-5-131 (XJB) to restore muscle contractility and mitochondrial function in aged skeletal muscle. Male adult (5-month old) and aged (29-month old) Fischer Brown Norway (F344/BN) rats were treated with XJB for four weeks and contractile properties of single skeletal muscle fibres and activity of mitochondrial ETC complexes were determined at the end of the treatment period. XJB-treated old rats showed higher muscle contractility associated with prevention of protein oxidation in both muscle homogenate and mitochondria compared with untreated counterparts. XJB-treated animals demonstrated a high activity of the respiratory complexes I, III, and IV with no changes in citrate synthase activity. These data demonstrate that mitochondrial ROS play a causal role in muscle weakness, and that a ROS scavenger specifically targeted to mitochondria can reverse age-related alterations of mitochondrial function and improve contractile properties in skeletal muscle.

  1. Myofascial force transmission between antagonistic rat lower limb muscles: Effects of single muscle or muscle group lengthening

    NARCIS (Netherlands)

    Meijer, Hanneke J.M; Rijkelijkhuizen, Josina M.; Huijing, Peter A.

    2007-01-01

    Effects of lengthening of the whole group of anterior crural muscles (tibialis anterior and extensor hallucis longus muscles (TA + EHL) and extensor digitorum longus (EDL)) on myofascial interaction between synergistic EDL and TA + EHL muscles, and on myofascial force transmission between anterior c

  2. Heat stress attenuates skeletal muscle atrophy of extensor digitorum longus in streptozotocin-induced diabetic rats.

    Science.gov (United States)

    Nonaka, K; Une, S; Akiyama, J

    2015-09-01

    To investigate whether heat stress attenuates skeletal muscle atrophy of the extensor digitorum longus (EDL) muscle in streptozotocin-induced diabetic rats, 12-week-old male Wistar rats were randomly assigned to four groups (n = 6 per group): control (Con), heat stress (HS), diabetes mellitus (DM), and diabetes mellitus/heat stress (DM + HS). Diabetes was induced by intraperitoneal injection of streptozotocin (50 mg/kg). Heat stress was induced in the HS and DM + HS groups by immersion of the lower half of the body in hot water at 42 °C for 30 min; it was initiated 7 days after injection of streptozotocin, and was performed once a day, five times a week for 3 weeks. The muscle fiber cross-sectional area of EDL muscles from diabetic and non-diabetic rats was determined; heat stress protein (HSP) 72 and HSP25 expression levels were also analyzed by western blotting. Diabetes-induced muscle fiber atrophy was attenuated upon heat stress treatment in diabetic rats. HSP72 and HSP25 expression was upregulated in the DM + HS group compared with the DM group. Our findings suggest that heat stress attenuates atrophy of the EDL muscle by upregulating HSP72 and HSP25 expression.

  3. THE EFFECTS OF CREATINE LONG-TERM SUPPLEMENTATION ON MUSCLE MORPHOLOGY AND SWIMMING PERFORMANCE IN RATS

    Directory of Open Access Journals (Sweden)

    Sena Erdal

    2009-12-01

    Full Text Available Creatine (Cr has been shown to increase the total muscle mass. The purpose of this study was to investigate the effect of Cr supplementation on muscle morphology and swimming performance, using an animal model. Each rat was subjected to exercise 15-minute period daily for the 12 weeks. The rats were randomly divided into four groups: no Cr supplementation (CON, no Cr supplementation and incomplete food intake (lacking lysine and methionine in diet for rats (INCO, Cr supplementation 1 g·kg-1·day-1 (CREAT-I and Cr supplementation 2 g·kg-1·day-1 (CREAT-II. Three months later, all groups adult rats exercised in swimming pool chambers. Swimming time was recorded as minute for each rat. Following swimming performance period, the animals were killed by cervical dislocation and the gastrocnemius and diaphragm muscles were dissected. Serial slices of 5-7 μm were allocated paraffin wax and histochemical staining procedure of cross-sections was carried out with heamatoxylin-eosin technics. All groups gained body weight at the end of 12 weeks but there was no statistical difference among them. Swimming time values were statistical difference between CREAT-II and CON group as well as between CREAT-I and CON group (p < 0.05. In the INCO group was determined increased connective tissue cell of the muscle sample. In contrast, in the CREAT-I and CREAT-II group, the basic histological changes were large-scale muscle fibers and hypertrophic muscle cells. These results suggest that long-term creatine supplementation increased the number of muscle fibers and enhanced endurance swimming performance in rats

  4. Localized infusion of IGF-I results in skeletal muscle hypertrophy in rats

    Science.gov (United States)

    Adams, G. R.; McCue, S. A.

    1998-01-01

    Insulin-like growth factor I (IGF-I) peptide levels have been shown to increase in overloaded skeletal muscles (G. R. Adams and F. Haddad. J. Appl. Physiol. 81: 2509-2516, 1996). In that study, the increase in IGF-I was found to precede measurable increases in muscle protein and was correlated with an increase in muscle DNA content. The present study was undertaken to test the hypothesis that direct IGF-I infusion would result in an increase in muscle DNA as well as in various measurements of muscle size. Either 0.9% saline or nonsystemic doses of IGF-I were infused directly into a non-weight-bearing muscle of rats, the tibialis anterior (TA), via a fenestrated catheter attached to a subcutaneous miniosmotic pump. Saline infusion had no effect on the mass, protein content, or DNA content of TA muscles. Local IGF-I infusion had no effect on body or heart weight. The absolute weight of the infused TA muscles was approximately 9% greater (P protein and DNA content of TA muscles (P DNA-to-protein ratio of the hypertrophied TA was similar to that of the contralateral muscles. These results suggest that IGF-I may be acting to directly stimulate processes such as protein synthesis and satellite cell proliferation, which result in skeletal muscle hypertrophy.

  5. Identification of a skeletal muscle-specific regulatory domain in the rat GLUT4/muscle-fat gene.

    Science.gov (United States)

    Richardson, J M; Pessin, J E

    1993-10-05

    To identify sequences responsible for the muscle-specific expression of the rat GLUT4/muscle-fat gene, we examined the transcriptional regulation of this gene in the differentiating murine C2C12 skeletal muscle cell line. Differentiated myofibers displayed a 4-5-fold increase in GLUT4 mRNA compared with undifferentiated myoblasts which paralleled the conversion from non-muscle beta-actin mRNA to muscle-specific alpha-actin mRNA expression. Transient transfection of progressive 5' and 3' deletions of the GLUT4 5'-flanking DNA identified a 281-base pair region located between -517 and -237 relative to the transcription start site which conferred myotube-specific expression. This region increased reporter activity in the context of the GLUT4 minimal promoter in an orientation-independent manner and, in addition, onto the heterologous thymidine kinase promoter. Myotube-specific expression of both GLUT4 reporter constructs and the endogenous mouse GLUT4 mRNA was also observed to be thyroid hormone-dependent. Further, cotransfection of reporter constructs containing the 281-base pair GLUT4 differentiation-specific enhancer with the thyroid hormone receptor specifically increased luciferase activity in myotubes approximately 12-fold. Thus, these data demonstrate the presence of a proximal skeletal muscle-specific activation domain that is necessary for both myotube-specific GLUT4 expression and thyroid hormone responsiveness.

  6. Is there morphological difference between branchiomeric and somitic muscles submitted to alcohol consumption? An experimental study in rats (Rattus norvegicus Existe diferença morfológica entre músculos branquioméricos e somíticos submetidos ao consumo de alcool? Um estudo experimental em ratos (Rattus norvegicus

    Directory of Open Access Journals (Sweden)

    Jesus Carlos Andreo

    2005-09-01

    Full Text Available Alcoholism is considered a physical dependence disorder. More than 18 million people are alcoholics in the USA and England and between 1/3 to ½ of them present some kind of physical disorder. In general the literature is focused on alcoholic trunk muscle disorders. These muscles have different embryological origins if compared to the masticatory muscles. The aim of this research was to evaluate the effects of alcohol on the masticatory muscles in order to compare them with the somitic muscles. For this purpose, 15 male Wistar rats weighing around 250g were used. The rats were divided into three groups: Normal control (N, Alcoholic (A and Isocaloric (I. Slices of the masseter muscle, temporalis muscle and rectus abdominal muscle were harvested and submitted to histochemical reactions (m-ATPase: acid and alkaline pre incubation and NADH-TR. The myofibers were classified in SO, FOG and FG. The results showed atrophy of the fast fibers (FG and FOG in the masticatory muscles but this atrophy was not statistically significant in this study (pO alcoolismo é considerado uma doença que causa desordens físicas e também dependência. Mais de 18 milhões de pessoas nos Estados Unidos são alcoólatras e na Inglaterra, entre 1/3 à ½ delas apresentam algum tipo de desordem física. No geral a literatura está focada para as desordens que acometem os músculos do tronco. Esses músculos têm origem embriológica diferente dos músculos da mastigação. O propósito desta pesquisa foi avaliar o efeito do álcool sobre os músculos da mastigação (branquiméricos no intuito de compará-lo com as alterações que ocorrem nos músculos do tronco (miotômicos. Para isso 15 ratos machos Wistar, pesando ao redor de 250g foram utilizados. Os animais foram divididos em três grupos: Controle normal (N; Alcoolizado (A e Isocalórico (I. Fragmentos dos músculos masseter, temporal e reto do abdome foram coletados e submetidos às reações de m-ATPase (com pr

  7. Masticatory muscles in the muscular dystrophic mouse. Aspects of the age-related progression of the disease

    DEFF Research Database (Denmark)

    Vilmann, H; Kirkeby, S

    1988-01-01

    Cross-sections of normal and dystrophic digastric and masseter muscles from 7- and 35- to 40-week-old mice were studied in the light microscope. Comparisons of mean cell size, cell size variance and number of centrally positioned nuclei in a given number of fibers were carried out. The masseter m...... muscle seems at both ages to be far more affected by the disease than the digastric muscle. However, the progression of the disease from 7 to 40 weeks is more pronounced in the digastric muscle than in the masseter muscle....

  8. Titin Isoform Size is Not Correlated with Thin Filament Length in Rat Skeletal Muscle

    Directory of Open Access Journals (Sweden)

    Marion Lewis Greaser

    2014-02-01

    Full Text Available The mechanisms controlling thin filament length in muscle remain controversial. It was recently reported that thin filament length was related to titin size, and that the latter might be involved in thin filament length determination. Titin plays several crucial roles in the sarcomere, but its function as it pertains to the thin filament has not been explored. We tested this relationship using several muscles from wild type rats and from a mutant rat model which results in increased titin size. Myofibrils were isolated from skeletal muscles (extensor digitorum longus, external oblique, gastrocnemius, longissimus dorsi, psoas major, and tibialis anterior using both adult wild type (WT and homozygous mutant (HM rats. Phalloidin and antibodies against tropomodulin-4 and nebulin’s N-terminus were used to determine thin filament length. The WT rats studied express skeletal muscle titin sizes ranging from 3.2 to 3.7 MDa, while the HM rats express a giant titin isoform sized at 3.7 MDa. No differences in phalloidin-based thin filament length, nebulin N terminus distances from the Z line, or tropomodulin distances from the Z line were observed across genotypes. The data indicates that, although titin performs many sarcomeric functions, its correlation with thin filament length and structure could not be demonstrated in the rat. Current models of thin filament assembly are inadequate to explain the phalloidin, nebulin N terminus, and tropomodulin staining patterns in the myofibril.

  9. Skeletal Muscle Regeneration in a Rat (Rattus norvegicus) Model with CorMatrix and Adipose Derived Stem Cells

    Science.gov (United States)

    2015-07-16

    not provide a regenerative scaffold for growth of skeletal muscle after volumetric muscle loss. 12. PROTOCOL OUTCOME SUMMARY: (Please provide, in...additional pages if necessary.) PROTOCOL #: FDG20130044A DATE: 16 July 2015 PROTOCOL TITLE: "Skeletal Muscle Regeneration in a Rat (Rattus no1Vegicus...volumetric muscle loss, with a clinical need for enhanced repair. Extracellular matrix (ECM) shows promise to regenerate skeletal muscle , opening a

  10. Dietary fat influences the expression of contractile and metabolic genes in rat skeletal muscle.

    Directory of Open Access Journals (Sweden)

    Wataru Mizunoya

    Full Text Available Dietary fat plays a major role in obesity, lipid metabolism, and cardiovascular diseases. To determine whether the intake of different types of dietary fats affect the muscle fiber types that govern the metabolic and contractile properties of the skeletal muscle, we fed male Wistar rats with a 15% fat diet derived from different fat sources. Diets composed of soybean oil (n-6 polyunsaturated fatty acids (PUFA-rich, fish oil (n-3 PUFA-rich, or lard (low in PUFAs were administered to the rats for 4 weeks. Myosin heavy chain (MyHC isoforms were used as biomarkers to delineate the skeletal muscle fiber types. Compared with soybean oil intake, fish oil intake showed significantly lower levels of the fast-type MyHC2B and higher levels of the intermediate-type MyHC2X composition in the extensor digitorum longus (EDL muscle, which is a fast-type dominant muscle. Concomitantly, MyHC2X mRNA levels in fish oil-fed rats were significantly higher than those observed in the soybean oil-fed rats. The MyHC isoform composition in the lard-fed rats was an intermediate between that of the fish oil and soybean oil-fed rats. Mitochondrial uncoupling protein 3, pyruvate dehydrogenase kinase 4, and porin mRNA showed significantly upregulated levels in the EDL of fish oil-fed rats compared to those observed in soybean oil-fed and lard-fed rats, implying an activation of oxidative metabolism. In contrast, no changes in the composition of MyHC isoforms was observed in the soleus muscle, which is a slow-type dominant muscle. Fatty acid composition in the serum and the muscle was significantly influenced by the type of dietary fat consumed. In conclusion, dietary fat affects the expression of genes related to the contractile and metabolic properties in the fast-type dominant skeletal muscle, where the activation of oxidative metabolism is more pronounced after fish oil intake than that after soybean oil intake.

  11. Evaluation of Histological Changes in Back Muscle Injuries in Rats over Time

    Science.gov (United States)

    Inage, Kazuhide; Sakuma, Yoshihiro; Orita, Sumihisa; Yamauchi, Kazuyo; Suzuki, Miyako; Kubota, Go; Oikawa, Yasuhiro; Sainoh, Takeshi; Sato, Jun; Fujimoto, Kazuki; Shiga, Yasuhiro; Kanamoto, Hirohito; Takahashi, Kazuhisa; Ohtori, Seiji

    2017-01-01

    Study Design Animal model study. Purpose The purpose of this study was to evaluate the histological variation in the injured muscle and production of calcitonin gene-related peptide in rats over time. Overview of Literature Vertebral surgery has been reported to cause atrophy of the back muscles, which may result in pain. However, few reports have described the time series histological variation in the injured muscle and changes in the dominant nerve. Methods We used 30 male, 8-week-old Sprague-Dawley rats. The right and left sides of the paravertebral muscle were considered as the injured and uninjured sides, respectively. A 115 g weight was dropped from a height of 1 m on the right paravertebral muscle. Hematoxylin and eosin (H&E) staining of the muscle was performed 1–3 weeks after injury for histological evaluation. Fluoro-Gold (FG) was injected into the paravertebral muscle. The L2 dorsal root ganglia on both sides were resected 1, 2, and 3 weeks after injury, and immunohistochemical staining for calcitonin gene-related peptide was performed. Results H&E staining of the paravertebral muscle showed infiltration of inflammatory cells and the presence of granulation tissue in the injured part on the ipsilateral side 1 week after injury. Muscle atrophy occurred 3 weeks after injury, but was repaired via spontaneous replacement of muscle cells/fibers. In contrast, compared with the uninjured side, the percentage of cells double-labeled with FG and calcitonin gene-related peptide in FG-positive cells in the dorsal root ganglia of the injured side was significantly increased at each time point throughout the study period. Conclusions These results suggest that sensitization of the dominant nerve in the dorsal root ganglia, which may be caused by cicatrix formation, can protract injured muscle pain. This information may be helpful in elucidating the underlying mechanism of persistent pain after back muscle injury.

  12. Age-dependent Muscle Adaptation after Chronic Stretch-shortening Contractions in Rats.

    Science.gov (United States)

    Rader, Erik P; Layner, KaylaN; Triscuit, Alyssa M; Chetlin, Robert D; Ensey, James; Baker, Brent A

    2016-01-01

    Age-related differences in contraction-induced adaptation have been well characterized especially for young and old rodent models but much less so at intermediate ages. Therefore, additional research is warranted to determine to what extent alterations in adaptation are due to maturation versus aging per se. The purpose of our study was to evaluate muscles of Fisher 344XBrown Norway rats of various ages following one month of exposure to stretch-shortening contractions (SSCs). With exposure, muscles mass increased by ~10% for 27 and 30 month old rats vs. ~20% for 3 and 6 month old rats (P muscle performance in general beginning at late adulthood. Such findings motivate careful investigation to determine appropriate SSC exposures at all stages of life.

  13. Induction of amino acid transporters expression by endurance exercise in rat skeletal muscle

    Energy Technology Data Exchange (ETDEWEB)

    Murakami, Taro, E-mail: tamuraka@sgk.ac.jp; Yoshinaga, Mariko

    2013-10-04

    Highlights: •Regulation of amino acid transporter expression in working muscle remains unclear. •Expression of amino acid transporters for leucine were induced by a bout of exercise. •Requirement of leucine in muscle cells might regulate expression of its transporters. •This information is beneficial for understanding the muscle remodeling by exercise. -- Abstract: We here investigated whether an acute bout of endurance exercise would induce the expression of amino acid transporters that regulate leucine transport across plasma and lysosomal membranes in rat skeletal muscle. Rats ran on a motor-driven treadmill at a speed of 28 m/min for 90 min. Immediately after the exercise, we observed that expression of mRNAs encoding L-type amino acid transporter 1 (LAT1) and CD98 was induced in the gastrocnemius, soleus, and extensor digitorum longus (EDL) muscles. Sodium-coupled neutral amino acid transporter 2 (SNAT2) mRNA was also induced by the exercise in those three muscles. Expression of proton-assisted amino acid transporter 1 (PAT1) mRNA was slightly but not significantly induced by a single bout of exercise in soleus and EDL muscles. Exercise-induced mRNA expression of these amino acid transporters appeared to be attenuated by repeated bouts of the exercise. These results suggested that the expression of amino acid transporters for leucine may be induced in response to an increase in the requirement for this amino acid in the cells of working skeletal muscles.

  14. Temporal profile of rat skeletal muscle capillary haemodynamics during recovery from contractions

    Science.gov (United States)

    Ferreira, Leonardo F; Padilla, Danielle J; Musch, Timothy I; Poole, David C

    2006-01-01

    In skeletal muscle capillaries, red blood cell (RBC) flux (FRBC), velocity (VRBC) and haematocrit (HctCAP) are key determinants of microvascular O2 exchange. However, the mechanisms leading to the changes in FRBC, VRBC and HctCAP during muscle contractions and recovery thereafter are not fully understood. To address this issue we used intravital microscopy to investigate the temporal profile of the rat spinotrapezius muscle (n = 5) capillary haemodynamics during recovery from 3 min of twitch muscle contractions (1 Hz, 4–6 V). Specifically, we hypothesized that (1) during early recovery FRBC and VRBC would decrease rapidly and FRBC would display a biphasic response (consistent with a muscle pump effect on capillary haemodynamics), and (2) there would be a dynamic relationship between changes (Δ) in VRBC and HctCAP. The values at rest (R) and end-recovery (ER) were significantly lower (P 0.05). Based on the early decrease in FRBC(within 5 s), overall dynamic profile of FRBC and the ∼20 s ‘delay’ to the decrease in VRBC we conclude that the muscle pump does not appear to contribute substantially to the steady-state capillary haemodynamics in the contracting rat spinotrapezius muscle. Moreover, our findings suggest that alterations in VRBC do not obligate proportional changes in HctCAP within individual capillaries following muscle contractions. PMID:16581868

  15. Contraction-associated translocation of protein kinase C in rat skeletal muscle

    DEFF Research Database (Denmark)

    Richter, Erik; Cleland, P J; Rattigan, S

    1987-01-01

    Electrical stimulation of the sciatic nerve of the anaesthetized rat in vivo led to a time-dependent translocation of protein kinase C from the muscle cytosol to the particulate fraction. Maximum activity of protein kinase C in the particulate fraction occurred after 2 min of intermittent short t...... tetanic contractions of the gastrocnemius-plantaris-soleus muscle group and coincided with the loss of activity from the cytosol. Translocation of protein kinase C may imply a role for this kinase in contraction-initiated changes in muscle metabolism.......Electrical stimulation of the sciatic nerve of the anaesthetized rat in vivo led to a time-dependent translocation of protein kinase C from the muscle cytosol to the particulate fraction. Maximum activity of protein kinase C in the particulate fraction occurred after 2 min of intermittent short...

  16. Contraction-induced muscle fiber damage is increased in soleus muscle of streptozotocin-diabetic rats and is associated with elevated expression of brain-derived neurotrophic factor mRNA in muscle fibers and activated satellite cells

    NARCIS (Netherlands)

    Copray, S; Liem, R; Brouwer, N; Greenhaff, P; Habens, F; Fernyhough, P

    The expression of brain-derived neurotrophic factor (BDNF) is elevated in the soleus muscle of streptozotocin-diabetic rats. To determine whether this diabetes-induced elevation was associated with or enhanced by muscle activity we have induced high-intensity muscle contraction by electrically

  17. Contraction-induced muscle fiber damage is increased in soleus muscle of streptozotocin-diabetic rats and is associated with elevated expression of brain-derived neurotrophic factor mRNA in muscle fibers and activated satellite cells

    NARCIS (Netherlands)

    Copray, S; Liem, R; Brouwer, N; Greenhaff, P; Habens, F; Fernyhough, P

    2000-01-01

    The expression of brain-derived neurotrophic factor (BDNF) is elevated in the soleus muscle of streptozotocin-diabetic rats. To determine whether this diabetes-induced elevation was associated with or enhanced by muscle activity we have induced high-intensity muscle contraction by electrically stimu

  18. Activation of the ATP-ubiquitin-proteasome pathway in skeletal muscle of cachectic rats bearing a hepatoma

    Science.gov (United States)

    Baracos, V. E.; DeVivo, C.; Hoyle, D. H.; Goldberg, A. L.

    1995-01-01

    Rats implanted with Yoshida ascites hepatoma (YAH) show a rapid and selective loss of muscle protein due mainly to a marked increase (63-95%) in the rate of protein degradation (compared with rates in muscles of pair-fed controls). To define which proteolytic pathways contribute to this increase, epitrochlearis muscles from YAH-bearing and control rats were incubated under conditions that modify different proteolytic systems. Overall proteolysis in either group of rats was not affected by removal of Ca2+ or by blocking the Ca(2+)-dependent proteolytic system. Inhibition of lysosomal function with methylamine reduced proteolysis (-12%) in muscles from YAH-bearing rats, but not in muscles of pair-fed rats. When ATP production was also inhibited, the remaining accelerated proteolysis in muscles of tumor-bearing rats fell to control levels. Muscles of YAH-bearing rats showed increased levels of ubiquitin-conjugated proteins and a 27-kDa proteasome subunit in Western blot analysis. Levels of mRNA encoding components of proteolytic systems were quantitated using Northern hybridization analysis. Although their total RNA content decreased 20-38%, pale muscles of YAH-bearing rats showed increased levels of ubiquitin mRNA (590-880%) and mRNA for multiple subunits of the proteasome (100-215%). Liver, kidney, heart, and brain showed no weight loss and no change in these mRNA species. Muscles of YAH-bearing rats also showed small increases (30-40%) in mRNA for cathepsins B and D, but not for calpain I or heat shock protein 70. Our findings suggest that accelerated muscle proteolysis and muscle wasting in tumor-bearing rats result primarily from activation of the ATP-dependent pathway involving ubiquitin and the proteasome.

  19. Ectopic development of skeletal muscle induced by subcutaneous transplant of rat satellite cells

    Directory of Open Access Journals (Sweden)

    M.G. Fukushima

    2005-03-01

    Full Text Available The present study analyzes the ectopic development of the rat skeletal muscle originated from transplanted satellite cells. Satellite cells (10(6 cells obtained from hindlimb muscles of newborn female 2BAW Wistar rats were injected subcutaneously into the dorsal area of adult male rats. After 3, 7, and 14 days, the transplanted tissues (N = 4-5 were processed for histochemical analysis of peripheral nerves, inactive X-chromosome and acetylcholinesterase. Nicotinic acetylcholine receptors (nAChRs were also labeled with tetramethylrhodamine-labeled alpha-bungarotoxin. The development of ectopic muscles was successful in 86% of the implantation sites. By day 3, the transplanted cells were organized as multinucleated fibers containing multiple clusters of nAChRs (N = 2-4, resembling those from non-innervated cultured skeletal muscle fibers. After 7 days, the transplanted cells appeared as a highly vascularized tissue formed by bundles of fibers containing peripheral nuclei. The presence of X chromatin body indicated that subcutaneously developed fibers originated from female donor satellite cells. Differently from the extensor digitorum longus muscle of adult male rat (87.9 ± 1.0 µm; N = 213, the diameter of ectopic fibers (59.1 µm; N = 213 did not obey a Gaussian distribution and had a higher coefficient of variation. After 7 and 14 days, the organization of the nAChR clusters was similar to that of clusters from adult innervated extensor digitorum longus muscle. These findings indicate the histocompatibility of rats from 2BAW colony and that satellite cells transplanted into the subcutaneous space of adult animals are able to develop and fuse to form differentiated skeletal muscle fibers.

  20. Three-O-methylglucose transport in soleus muscle of bacteremic rats

    Energy Technology Data Exchange (ETDEWEB)

    Westfall, M.V.; Sayeed, M.M.

    1987-07-01

    Basal and insulin-stimulated soleus muscle 3-O-(/sup 14/C)merhylglucose ((/sup 14/C)-3-O-MG) transport was studied in vitro and in vivo during bacteremia in rats. Fasted rats were injected with Escherichia coli to produce bacteremia (B), and controls (C) received saline. In vitro studies using soleus muscles were carried out 8 of 12 hr after bacterial injection, and transport was measured using the rate coefficient (lambda = min/sup /minus/1/). Although insulin-stimulated (/sup 14/C)-3-O-MG transport was decreased in 12-h bacteremic rat muscles the basal (/sup 14/C)-3-O-MG transport was rate coefficient was elevated. For in vivo studies, (/sup 14/C)-3-O-MG with or without insulin was injected into rats 10-40 min prior to removing soleus muscles at 12 h postbacterial or postsaline injection. Transport was measured as the ratio of (/sup 14/C)-3-O-MG/sub intracell//(/sup 14/C)-3-O-MG/sub extracell/. Basal ratios were not different and muscles from both control and bacteremic rats responded comparably to insulin with increased (/sup 14/C)-3-O-MG transport during the initial 30 min. At 35-40 min postinsulin injection there was a further stimulation of (/sup 14/C)-3-O-MG transport in control but not in 12-h bacteremic rat muscles. The changes in (/sup 14/C)-3-O-MG transport observed in vitro and in vivo after 12 h of bacteremia may be due to circulating mediators and/or changes in membrane function.

  1. PAT1 (SLC36A1) shows nuclear localization and affect growth of smooth muscle cells from rats

    DEFF Research Database (Denmark)

    Jensen, Anne; Figueiredo-Larsen, Evan Manuel; Holm, René

    2014-01-01

    the localization and function of PAT1 in smooth muscle cells (SMCs). The PAT1 protein was found in smooth muscles from rat intestine and in the embryonic rat aorta cell line A7r5. Immunolocalization and cellular fractionation studies revealed that the majority of the PAT1 protein located within the cell nucleus...

  2. Localized infusion of IGF-I results in skeletal muscle hypertrophy in rats

    Science.gov (United States)

    Adams, G. R.; McCue, S. A.

    1998-01-01

    Insulin-like growth factor I (IGF-I) peptide levels have been shown to increase in overloaded skeletal muscles (G. R. Adams and F. Haddad. J. Appl. Physiol. 81: 2509-2516, 1996). In that study, the increase in IGF-I was found to precede measurable increases in muscle protein and was correlated with an increase in muscle DNA content. The present study was undertaken to test the hypothesis that direct IGF-I infusion would result in an increase in muscle DNA as well as in various measurements of muscle size. Either 0.9% saline or nonsystemic doses of IGF-I were infused directly into a non-weight-bearing muscle of rats, the tibialis anterior (TA), via a fenestrated catheter attached to a subcutaneous miniosmotic pump. Saline infusion had no effect on the mass, protein content, or DNA content of TA muscles. Local IGF-I infusion had no effect on body or heart weight. The absolute weight of the infused TA muscles was approximately 9% greater (P hypertrophied TA was similar to that of the contralateral muscles. These results suggest that IGF-I may be acting to directly stimulate processes such as protein synthesis and satellite cell proliferation, which result in skeletal muscle hypertrophy.

  3. Effects of 8 wk of voluntary unloaded wheel running on K+ tolerance and excitability of soleus muscles in rat.

    Science.gov (United States)

    Broch-Lips, Martin; de Paoli, Frank; Pedersen, Thomas Holm; Overgaard, Kristian; Nielsen, Ole Bækgaard

    2011-07-01

    During intense exercise, efflux of K(+) from working muscles increases extracellular K(+) ([K(+)](o)) to levels that can compromise muscle excitability and hence cause fatigue. In this context, the reduction in the exercise-induced elevation of [K(+)](o) observed after training in humans is suggested to contribute to the increased performance after training. Although a similar effect could be obtained by an increase in the tolerance of muscle to elevated [K(+)](o), this possibility has not been investigated. To examine this, isolated soleus muscles from sedentary (sedentary) rats and from rats that had voluntarily covered 13.1 ± 0.7 km/day in an unloaded running wheel for 8 wk (active) were compared. In muscles from active rats, the loss of force induced by exposure to an elevated [K(+)](o) of 9 mM was 42% lower than in muscles from sedentary rats (P fibers (P fiber action potentials (AP), and higher Na(+)/K(+) pump content. When stimulated intermittently at 6.5 mM K(+), muscles from active rats displayed better endurance than muscles from sedentary rats, whereas no difference was found when the muscles were stimulated continuously at 30 or 120 Hz. We conclude that voluntary running increases muscle excitability, leading to improved tolerance to elevated [K(+)](o).

  4. Effects of estrogen on gastrocnemius muscle strain injury and regeneration in female rats

    Institute of Scientific and Technical Information of China (English)

    XinFENG; Guo-zhenLI; ShengWANG

    2004-01-01

    AIM: To study the effects of estrogen on muscle damage and regeneration after acute passive gastrocnemius muscle strain injury in female Sprague-Dawley rats. METHODS: Rats were divided into 5 groups: ovariectomized, strained and treated with low-dosage estradiol (20μg/d) (Elow), treated with high-dosage estradiol (200 lag/d) (Ehigh), treated with oil placebo (Oil), strained with no ovariectomy (Strain), and sham operated with no strain and no ovariectomy (Con). Muscle damage index [plasma creatine kinase (CK)], antioxidant indexes [glutathione (GSH), Vitamin E (Vit E), total antioxidant capability (TAC)], and muscle regeneration index (desmin) were investigated at 7d. RESULTS: The plasma CK activity increased but GSH, Vit E, and TAC levels decreased after muscle strain injury (Strain vs Con P<0.05). Plasma CK activity was the greatest while GSH, Vit E, and TAC were the lowest in the Oil group among the five groups (P<0.01). Plasma CK in the Ehigh and Strain groups was lower than that in the Elow group. Plasma GSH, Vit E, and TAC were higher in the Ehigh and Strain groups compared with the Elow group (P<0.05). The expression of desmin in the Ehigh and Strain groups was higher than that in the Elow group (P<0.01) while that in the Oil group was the lowest in all the five groups (P<0.01). CONCLUSION: Endogenous estrogen in normal female rats or exogenous estrogen in ovariectomized rats could improve antioxidant capability in vivo, so that reduced muscle damage and accelerated muscle regeneration post gastronemius muscle strain injury.

  5. Effects of estrogen on gastrocnemius muscle strain injury and regeneration in female rats

    Institute of Scientific and Technical Information of China (English)

    Xin FENG; Guo-zhen LI; Sheng WANG

    2004-01-01

    AIM: To study the effects of estrogen on muscle damage and regeneration after acute passive gastrocnemius muscle strain injury in female Sprague-Dawley rats. METHODS: Rats were divided into 5 groups: ovariectomized,strained and treated with low-dosage estradiol (20 μg/d) (Elow), treated with high-dosage estradiol (200 μg/d) (Ehigh),treated with oil placebo (Oil), strained with no ovariectomy (Strain), and sham operated with no strain and no ovariectomy (Con). Muscle damage index [plasma creatine kinase (CK)], antioxidant indexes [glutathione (GSH),Vitamin E (Vit E), total antioxidant capability (TAC)], and muscle regeneration index (desmin) were investigated at7 d. RESULTS: The plasma CK activity increased but GSH, Vit E, and TAC levels decreased after muscle strain injury (Strain vs Con P<0.05). Plasma CK activity was the greatest while GSH, Vit E, and TAC were the lowest in the Oil group among the five groups (P<0.01). Plasma CK in the Ehigh and Strain groups was lower than that in the Elow group. Plasma GSH, Vit E, and TAC were higher in the Ehigh and Strain groups compared with the Elow group(P <0.05). The expression of desmin in the Ehigh and Strain groups was higher than that in the Elow group (P<0.01)while that in the Oil group was the lowest in all the five groups (P<0.01). CONCLUSION: Endogenous estrogen in normal female rats or exogenous estrogen in ovariectomized rats could improve antioxidant capability in vivo, so that reduced muscle damage and accelerated muscle regeneration post gastronemius muscle strain injury.

  6. Evaluation of the response of rat skeletal muscle to a model of weightlessness

    Science.gov (United States)

    Templeton, G. H.; Padalino, M.; Glasberg, M.; Manton, J.; Silver, P.; Sutko, J.

    1982-01-01

    Suspension of rats in a head-down tilt position such that their hind limbs are non-load bearing has been proposed as a model for weightlessness. Changes observed in metabolism, bone formation (Morey et al., 1979), and muscle catabolism (Mussachia et al., 1980) support the validity of the model. To further document this model, the effects of suspension on the mechanical, biochemical and histochemical characteristics of two hind limb skeletal muscles, the gastrocnemius and the soleus, are investigated.

  7. Lingual muscle activity across sleep-wake states in rats with surgically altered upper airway

    Directory of Open Access Journals (Sweden)

    Irma eRukhadze

    2014-04-01

    Full Text Available Obstructive sleep apnea (OSA patients have increased upper airway muscle activity, including such lingual muscles as the genioglossus (GG, geniohyoid (GH and hyoglossus (HG. This adaptation partially protects their upper airway against obstructions. Rodents are used to study the central neural control of sleep and breathing but they do not naturally exhibit OSA. We investigated whether, in chronically instrumented, behaving rats, disconnecting the GH and HG muscles from the hyoid (H apparatus would result in a compensatory increase of other upper airway muscle activity (EMG and/or other signs of upper airway instability. We first determined that, in intact rats, lingual (GG and intrinsic muscles maintained stable activity levels when quantified based on 2 h-long recordings conducted on days 6 through 22 after instrumentation. We then studied 5 rats in which the tendons connecting the GH and HG muscles to the H apparatus were experimentally severed. When quantified across all recording days, lingual EMG during SWS was modestly but significantly increased in rats with surgically altered upper airway (8.6% ±0.7(SE vs. 6.2% ±0.7 of the mean during wakefulness; p=0.012. Respiratory modulation of lingual EMG occurred mainly during SWS and was similarly infrequent in both groups, and the incidence of sighs and central apneas also was similar. Thus, a weakened action of selected lingual muscles did not produce sleep-disordered breathing but resulted in a relatively elevated activity in other lingual muscles during SWS. These results encourage more extensive surgical manipulations with the aim to obtain a rodent model with collapsible upper airway.

  8. Overload-induced skeletal muscle hypertrophy is not impaired in STZ-diabetic rats

    Science.gov (United States)

    Fortes, Marco Aurélio S; Pinheiro, Carlos Hermano J; Guimarães-Ferreira, Lucas; Vitzel, Kaio F; Vasconcelos, Diogo A A; Curi, Rui

    2015-01-01

    The aim of this study was to evaluate the effect of overload-induced hypertrophy on extensor digitorum longus (EDL) and soleus muscles of streptozotocin-induced diabetic rats. The overload-induced hypertrophy and absolute tetanic and twitch forces increases in EDL and soleus muscles were not different between diabetic and control rats. Phospho-Akt and rpS6 contents were increased in EDL muscle after 7 days of overload and returned to the pre-overload values after 30 days. In the soleus muscle, the contents of total and phospho-Akt and total rpS6 were increased in both groups after 7 days. The contents of total Akt in controls and total rpS6 and phospho-Akt in the diabetic rats remained increased after 30 days. mRNA expression after 7 days of overload in the EDL muscle of control and diabetic animals showed an increase in MGF and follistatin and a decrease in myostatin and Axin2. The expression of FAK was increased and of MuRF-1 and atrogin-1 decreased only in the control group, whereas Ankrd2 expression was enhanced only in diabetic rats. In the soleus muscle caused similar changes in both groups: increase in FAK and MGF and decrease in Wnt7a, MuRF-1, atrogin-1, and myostatin. Differences between groups were observed only in the increased expression of follistatin in diabetic animals and decreased Ankrd2 expression in the control group. So, insulin deficiency does not impair the overload-induced hypertrophic response in soleus and EDL muscles. However, different mechanisms seem to be involved in the comparable hypertrophic responses of skeletal muscle in control and diabetic animals. PMID:26197932

  9. Skeletal muscle afferent regulation of bioassayable growth hormone in the rat pituitary

    Science.gov (United States)

    Gosselink, K. L.; Grindeland, R. E.; Roy, R. R.; Zhong, H.; Bigbee, A. J.; Grossman, E. J.; Edgerton, V. R.

    1998-01-01

    There are forms of growth hormone (GH) in the plasma and pituitary of the rat and in the plasma of humans that are undetected by presently available immunoassays (iGH) but can be measured by bioassay (bGH). Although the regulation of iGH release is well documented, the mechanism(s) of bGH release is unclear. On the basis of changes in bGH and iGH secretion in rats that had been exposed to microgravity conditions, we hypothesized that neural afferents play a role in regulating the release of these hormones. To examine whether bGH secretion can be modulated by afferent input from skeletal muscle, the proximal or distal ends of severed hindlimb fast muscle nerves were stimulated ( approximately 2 times threshold) in anesthetized rats. Plasma bGH increased approximately 250%, and pituitary bGH decreased approximately 60% after proximal nerve trunk stimulation. The bGH response was independent of muscle mass or whether the muscles were flexors or extensors. Distal nerve stimulation had little or no effect on plasma or pituitary bGH. Plasma iGH concentrations were unchanged after proximal nerve stimulation. Although there may be multiple regulatory mechanisms of bGH, the present results demonstrate that the activation of low-threshold afferents from fast skeletal muscles can play a regulatory role in the release of bGH, but not iGH, from the pituitary in anesthetized rats.

  10. Skeletal muscle afferent regulation of bioassayable growth hormone in the rat pituitary

    Science.gov (United States)

    Gosselink, K. L.; Grindeland, R. E.; Roy, R. R.; Zhong, H.; Bigbee, A. J.; Grossman, E. J.; Edgerton, V. R.

    1998-01-01

    There are forms of growth hormone (GH) in the plasma and pituitary of the rat and in the plasma of humans that are undetected by presently available immunoassays (iGH) but can be measured by bioassay (bGH). Although the regulation of iGH release is well documented, the mechanism(s) of bGH release is unclear. On the basis of changes in bGH and iGH secretion in rats that had been exposed to microgravity conditions, we hypothesized that neural afferents play a role in regulating the release of these hormones. To examine whether bGH secretion can be modulated by afferent input from skeletal muscle, the proximal or distal ends of severed hindlimb fast muscle nerves were stimulated ( approximately 2 times threshold) in anesthetized rats. Plasma bGH increased approximately 250%, and pituitary bGH decreased approximately 60% after proximal nerve trunk stimulation. The bGH response was independent of muscle mass or whether the muscles were flexors or extensors. Distal nerve stimulation had little or no effect on plasma or pituitary bGH. Plasma iGH concentrations were unchanged after proximal nerve stimulation. Although there may be multiple regulatory mechanisms of bGH, the present results demonstrate that the activation of low-threshold afferents from fast skeletal muscles can play a regulatory role in the release of bGH, but not iGH, from the pituitary in anesthetized rats.

  11. Role of the trigeminal mesencephalic nucleus in rat whisker pad proprioception.

    Science.gov (United States)

    Mameli, Ombretta; Stanzani, Stefania; Mulliri, Gabriele; Pellitteri, Rosalia; Caria, Marcello A; Russo, Antonella; De Riu, Pierluigi

    2010-11-15

    Trigeminal proprioception related to rodent macrovibrissae movements is believed to involve skin receptors on the whisker pad because pad muscles operate without muscle spindles. This study was aimed to investigate in rats whether the trigeminal mesencephalic nucleus (TMnu), which provides proprioceptive feedback for chewing muscles, may be also involved in whisker pad proprioception. Two retrograde tracers, Dil and True Blue Chloride, were injected into the mystacial pad and the masseter muscle on the same side of deeply anesthetized rats to label the respective projecting sensory neurons. This double-labeling technique was used to assess the co-innervation of both structures by the trigeminal mesencephalic nucleus (TMnu).In a separate group of anesthetized animals, the spontaneous electrical activities of TMnu neurons were analyzed by extracellular recordings during spontaneous movements of the macrovibrissae. Mesencephalic neurons (TMne) were previously identified by their responses to masseter muscle stretching. Changes in TMne spontaneous electrical activities, analyzed under baseline conditions and during whisking movements, were statistically evaluated using Student's t-test for paired observations. Neuroanatomical experiments revealed different subpopulations of trigeminal mesencephalic neurons: i) those innervating the neuromuscular spindles of the masseter muscle, ii) those innervating the mystacial pad, and iii) those innervating both structures. Extracellular recordings made during spontaneous movements of the macrovibrisae showed that whisking neurons similar to those observed in the trigeminal ganglion were located in the TMnu. These neurons had different patterns of activation, which were dependent on the type of spontaneous macrovibrissae movement. In particular, their spiking activity tonically increased during fan-like movements of the vibrissae and showed phasic bursting during rhythmic whisking. Furthermore, the same neurons may also respond to

  12. Role of the trigeminal mesencephalic nucleus in rat whisker pad proprioception

    Directory of Open Access Journals (Sweden)

    Russo Antonella

    2010-11-01

    Full Text Available Abstract Background Trigeminal proprioception related to rodent macrovibrissae movements is believed to involve skin receptors on the whisker pad because pad muscles operate without muscle spindles. This study was aimed to investigate in rats whether the trigeminal mesencephalic nucleus (TMnu, which provides proprioceptive feedback for chewing muscles, may be also involved in whisker pad proprioception. Methods Two retrograde tracers, Dil and True Blue Chloride, were injected into the mystacial pad and the masseter muscle on the same side of deeply anesthetized rats to label the respective projecting sensory neurons. This double-labeling technique was used to assess the co-innervation of both structures by the trigeminal mesencephalic nucleus (TMnu. In a separate group of anesthetized animals, the spontaneous electrical activities of TMnu neurons were analyzed by extracellular recordings during spontaneous movements of the macrovibrissae. Mesencephalic neurons (TMne were previously identified by their responses to masseter muscle stretching. Changes in TMne spontaneous electrical activities, analyzed under baseline conditions and during whisking movements, were statistically evaluated using Student's t-test for paired observations. Results Neuroanatomical experiments revealed different subpopulations of trigeminal mesencephalic neurons: i those innervating the neuromuscular spindles of the masseter muscle, ii those innervating the mystacial pad, and iii those innervating both structures. Extracellular recordings made during spontaneous movements of the macrovibrisae showed that whisking neurons similar to those observed in the trigeminal ganglion were located in the TMnu. These neurons had different patterns of activation, which were dependent on the type of spontaneous macrovibrissae movement. In particular, their spiking activity tonically increased during fan-like movements of the vibrissae and showed phasic bursting during rhythmic whisking

  13. Metabolic adaptations of skeletal muscle to voluntary wheel running exercise in hypertensive heart failure rats

    DEFF Research Database (Denmark)

    Schultz, R L; Kullman, E L; Waters, Ryan

    2013-01-01

    The Spontaneously Hypertensive Heart Failure (SHHF) rat mimics the human progression of hypertension from hypertrophy to heart failure. However, it is unknown whether SHHF animals can exercise at sufficient levels to observe beneficial biochemical adaptations in skeletal muscle. Thirty-seven female...... SHHF and Wistar-Furth (WF) rats were randomized to sedentary (SHHFsed and WFsed) and exercise groups (SHHFex and WFex). The exercise groups had access to running wheels from 6-22 months of age. Hindlimb muscles were obtained for metabolic measures that included mitochondrial enzyme function...... and expression, and glycogen utilization. The SHHFex rats ran a greater distance and duration as compared to the WFex rats (Pmuscle citrate synthase and beta-hydroxyacyl-CoA dehydrogenase enzyme activity was not altered in the SHHFex group...

  14. Longitudinal and transversal displacements between triceps surae muscles during locomotion of the rat.

    Science.gov (United States)

    Bernabei, Michel; van Dieën, Jaap H; Maas, Huub

    2017-02-15

    The functional consequences of differential muscle activation and contractile behavior between mechanically coupled synergists are still poorly understood. Even though synergistic muscles exert similar mechanical effects at the joint they span, differences in the anatomy, morphology and neural drive may lead to non-uniform contractile conditions. This study aimed to investigate the patterns of activation and contractile behavior of triceps surae muscles, to understand how these contribute to the relative displacement between the one-joint soleus (SO) and two-joint lateral gastrocnemius (LG) muscle bellies and their distal tendons during locomotion in the rat. In seven rats, muscle belly lengths and muscle activation during level and upslope trotting were measured by sonomicrometry crystals and electromyographic electrodes chronically implanted in the SO and LG. Length changes of muscle-tendon units (MTUs) and tendon fascicles were estimated based on joint kinematics and muscle belly lengths. Distances between implanted crystals were further used to assess longitudinal and transversal deformations of the intermuscular volume between the SO and LG. For both slope conditions, we observed differential timing of muscle activation as well as substantial differences in contraction speeds between muscle bellies (maximal relative speed 55.9 mm s(-1)). Muscle lengths and velocities did not differ significantly between level and upslope locomotion, only EMG amplitude of the LG was affected by slope. Relative displacements between SO and LG MTUs were found in both longitudinal and transversal directions, yielding an estimated maximal length change difference of 2.0 mm between their distal tendons. Such relative displacements may have implications for the force exchanged via intermuscular and intertendinous pathways.

  15. Imbalance in SOD/CAT activities in rat skeletal muscles submitted to treadmill training exercise.

    Science.gov (United States)

    Pinho, Ricardo A; Andrades, Michael E; Oliveira, Marcos R; Pirola, Aline C; Zago, Morgana S; Silveira, Paulo C L; Dal-Pizzol, Felipe; Moreira, José Cláudio F

    2006-10-01

    The association between physical exercise and oxidative damage in the skeletal musculature has been the focus of many studies in literature, but the balance between superoxide dismutase and catalase activities and its relation to oxidative damage is not well established. Thus, the aim of the present study was to investigate the association between regular treadmill physical exercise, oxidative damage and antioxidant defenses in skeletal muscle of rats. Fifteen male Wistar rats (8-12 months) were randomly separated into two groups (trained n=9 and untrained n=6). Trained rats were treadmill-trained for 12 weeks in progressive exercise (velocity, time, and inclination). Training program consisted in a progressive exercise (10 m/min without inclination for 10 min/day). After 1 week the speed, time and inclination were gradually increased until 17 m/min at 10% for 50 min/day. After the training period animals were killed, and gastrocnemius and quadriceps were surgically removed to the determination of biochemical parameters. Lipid peroxidation, protein oxidative damage, catalase, superoxide dismutase and citrate synthase activities, and muscular glycogen content were measured in the isolated muscles. We demonstrated that there is a different modulation of CAT and SOD in skeletal muscle in trained rats when compared to untrained rats (increased SOD/CAT ratio). TBARS levels were significantly decreased and, in contrast, a significant increase in protein carbonylation was observed. These results suggest a non-described adaptation of skeletal muscle against exercise-induced oxidative stress.

  16. Vascularity of myocardium and gastrocnemius muscle in rats selectively bred for endurance running capacity.

    Science.gov (United States)

    Beighley, Patricia E; Zamir, Mair; Wentz, Robert J; Koch, Lauren G; Britton, Steven L; Ritman, Erik L

    2013-02-04

    We tested the hypothesis that changes in the arteriolar branching architecture contributed to increased running capacity of rats subjected to two-way artificial selection for intrinsic aerobic endurance treadmill running capacity resulting in strains of low-capacity and high-capacity endurance rats. Hearts and gastrocnemius muscles were harvested from each strain, and the microvasculature's branching geometry measured from micro-CT images. The vascular branching geometry of the hearts and skeletal muscle from the high capacity was indistinguishable from low-capacity rats. Our hypothesis was not supported. Neither remodeling nor an increase in arteriolar microvasculature branching appears to play a role in the enhanced performance of the high capacity rats. We are led to speculate that endothelial tolerance for shear stress and/or increased coupling of myocardial muscle fiber metabolic-to-contractile function is increased in the high-capacity runner strain to the effect of allowing either higher flow rate per unit volume of muscle or more efficient use of oxygen and nutrients in the high-capacity endurance rats.

  17. Effects of Charred Fructus Crataegi on the contractilily of isolated rat gastric and intestine muscle strips

    Institute of Scientific and Technical Information of China (English)

    ZHANG Hou-li; DIAO Yun-peng; LIU Zhi-hao; HUANG Shan-shan; MA Xiao-chi; LIN Yuan

    2008-01-01

    Objective The purpose of the study is to investigate the effects of Charred Fructus Crataegi Alcohol Extract on contractililty of isolated rat gastric and intesting smooth muscle strips. Methods Isolated rat intestine was selected in the assay to test the effects of Charred Fructus Crataegi Alcohol Extract on contractilty of isolated rat gastric and intestine smooth muscle strips using Krebs' solution, to observe the effects of in the presence of acetylcholine or atropine. Results Charred Fructus Crataegi Alcohol Extract in the range of 2-8 rag crude drugs/mL could significantly reduce the contractility of rat gastric and intestine smooth muscle strips in a dose-dependent manner, and Charred Fructus Crataegi Alcohol Extract 8 mg·mL-1(crude drugs) could inhibit the stimulation induced by acetylcholine. Charred Fructus Crataegi Alcohol Extract 8 mg·mL-1(crude drugs) was found to have a inhibiton of the relaxtion concurrently used with atropin. Conclusions The results suggest that Charred Fructus Crataegi Alcohol Extract has prominent inhibitory effects on the contractile activity of isolated rat gastric and intestine smooth muscle strips.

  18. Oxidative stress participates in quadriceps muscle dysfunction during the initiation of osteoarthritis in rats.

    Science.gov (United States)

    Hsu, Dur-Zong; Chu, Pei-Yi; Wu, Po-Ting; Shen, Po-Chuan; Jou, I-Ming

    2015-01-01

    Osteoarthritis is the most common form of arthritis, affecting approximately 15% of the population. Quadriceps muscle weakness is one of the risk factors of osteoarthritis development. Oxidative stress has been reported to play an important role in the pathogenesis of various muscle dysfunction; however, whether it is involved in osteoarthritis-associated quadriceps muscle weakness has never been investigated. The aim of the present study is to examine the involvement of oxidative stress in quadriceps muscle dysfunction in the initiation of osteoarthritis in rats. Rat osteoarthritis was initiated by conducting meniscectomy (MNX). Quadriceps muscle dysfunction was evaluated by assessing muscular interleukin-6, citrate synthase activity, and myosin heavy chain IIa mRNA expression levels. Muscular oxidative stress was assessed by determining lipid peroxidation, Nrf2 expression, reactive oxygen species, and circulating antioxidants. Increased muscular interleukin-6 production as well as decreased citrate synthase activity and myosin heavy chain IIa mRNA expression were observed at 7 and 14 days after MNX. Biomarkers of oxidative stress were significantly increased after MNX. Muscular free radical counts were increased while glutathione and glutathione peroxidase expression were decreased in MNX-treated rats. We conclude that oxidative stress may be involved in the pathogenesis of muscle dysfunction in MNX-induced osteoarthritis.

  19. Effects of muscle pain induced by glutamate injections during sustained clenching on the contraction pattern of masticatory muscles.

    Science.gov (United States)

    Michelotti, Ambrosina; Cioffi, Iacopo; Rongo, Roberto; Borrelli, Roberta; Chiodini, Paolo; Svensson, Peter

    2014-01-01

    To evaluate the contraction pattern of masticatory muscles during sustained clenching tasks with or without experimental pain induced by glutamate injection into the masseter muscle. It was hypothesized that acute muscle pain could induce compensatory changes in the electromyographic (EMG) activity of the masticatory muscles. Fifteen volunteers (seven males, mean age ± SD = 29.7 ± 1.1 years; eight females, mean age ± SD = 23.5 ± 1.2 years) were recruited in a crossover experimental study. All subjects participated in two randomized 20-minute experimental sessions. Each subject was asked to clench at 25% of the maximum voluntary contraction (MVC). After 10 minutes, isotonic saline or glutamate was injected in random order into the right masseter. EMG activity (root mean square [RMS] and mean power frequency [MPF]) was assessed in the masseter and anterior temporalis muscles on both sides. Pain and fatigue were assessed by 0-10 numeric rating scales (NRS) every minute. Differences between conditions (isotonic saline vs glutamate) for all the outcome parameters were analyzed by using a mixed effect model. The EMG activity of the masticatory muscles and pain and fatigue scores were not dependent on isotonic saline/glutamate injection (all P > .05). The RMS in the temporalis and masseter muscles increased with time (right masseter P = 0.001, left masseter P = .004, right temporalis P = .22, left temporalis P = .006), whereas the MPF decreased (right masseter P = .0001, left masseter P muscles during a sustained clenching task. This finding strongly suggests the adaptive capacity of the stomatognathic system in the presence of acute nociceptive inputs.

  20. Nociceptor interleukin 10 receptor 1 is critical for muscle analgesia induced by repeated bouts of eccentric exercise in the rat.

    Science.gov (United States)

    Alvarez, Pedro; Bogen, Oliver; Green, Paul G; Levine, Jon D

    2017-08-01

    Delayed-onset muscle soreness is typically observed after strenuous or unaccustomed eccentric exercise. Soon after recovery, blunted muscle soreness is observed on repeated eccentric exercise, a phenomenon known as repeated bout effect (RBE). Although regular physical activity decreases muscle hyperalgesia, likely because of increased production of the anti-inflammatory cytokine interleukin-10 (IL-10) in the skeletal muscle, whether IL-10 also contributes to the antinociceptive effect of RBE is unknown. Furthermore, whether IL-10 attenuates muscle hyperalgesia by acting on muscle nociceptors remains to be established. Here, we explored the hypothesis that blunted muscle nociception observed in RBE depends on a local effect of IL-10, acting on IL-10 receptor 1 (IL-10R1) expressed by muscle nociceptors. Results show that after a second bout of eccentric exercise, rats exhibited decreased muscle hyperalgesia, indicative of RBE, and increased expression of IL-10 in the exercised gastrocnemius muscle. Although knockdown of IL-10R1 protein in nociceptors innervating the gastrocnemius muscle by intrathecal antisense oligodeoxynucleotide did not change nociceptive threshold in naive rats, it unveiled latent muscle hyperalgesia in rats submitted to eccentric exercise 12 days ago. Furthermore, antisense also prevented the reduction of muscle hyperalgesia observed after a second bout of eccentric exercise. These data indicate that recovery of nociceptive threshold after eccentric exercise and RBE-induced analgesia depend on a local effect of IL-10, acting on its canonical receptor in muscle nociceptors.

  1. GENE RESPONSE OF THE GASTROCNEMIUS AND SOLEUS MUSCLES TO AN ACUTE AEROBIC RUN IN RATS

    Directory of Open Access Journals (Sweden)

    Michael J. McKenzie

    2011-06-01

    Full Text Available Genes can be activated or inhibited by signals within the tissues in response to an acute bout of exercise. It is unclear how a particular aerobic exercise bout may influence two muscles with similar actions to the activity. Therefore, the purposes of this investigation was to determine the gene response of selected genes involved in the "stress" response of the gastrocnemius (fast-twitch and soleus (slow-twitch muscles to a single two hour aerobic exercise bout in female Sprague-Dawley Rats at the 1 hour time point after the exercise. Exercised rats were run (n=8 for 2 hours at 20 m.min-1 and one hour after the completion of the bout had their soleus (S and gastrocnemius (G muscles removed. Age and timed matched sedentary control rats had both S and G muscles removed also. RNA was isolated from all muscles. Real-time PCR analysis was performed on the following genes: NFκB, TNFα, and Atf3. GAPDH was used as the housekeeping gene for both muscles. S muscle showed more genes altered (n = 52 vs G (n = 26. NFκB gene expression was 0.83 ± 0.14 in the exercised S but was + 1.36 ± 0.58 in the exercised G and was not significantly different between the muscles. TNFα was altered 1.30 ± 0. 34 in the exercised S and 1.36 ± 0.71 in the exercised G and was not significantly different between the muscles. The gene Atf3 was significantly altered at 4.97 ± 1.01 in the exercised S, while it was not significantly altered in the exercised G (0.70 ± 0.55. This study demonstrates that an acute bout of aerobic exercise can alter gene expression to a different extent in both the S and G muscles. It is highly likely that muscle recruitment was a factor which influenced the gene expression in theses muscles. It is interesting to note that some genes were similarly activated in these two muscles but other genes may demonstrate a varied response to the same exercise bout depending on the type of muscle

  2. Loquat (Eriobotrya japonica) extract prevents dexamethasone-induced muscle atrophy by inhibiting the muscle degradation pathway in Sprague Dawley rats.

    Science.gov (United States)

    Noh, Kyung Kyun; Chung, Ki Wung; Sung, Bokyung; Kim, Min Jo; Park, Chan Hum; Yoon, Changshin; Choi, Jae Sue; Kim, Mi Kyung; Kim, Cheol Min; Kim, Nam Deuk; Chung, Hae Young

    2015-09-01

    In the Orient, loquat (Eriobotrya japonica) extract (LE) is widely used in teas, food and folk medicines. The leaves of the loquat tree have been used for generations to treat chronic bronchitis, coughs, phlegm production, high fever and gastroenteric disorders. One of the major active components of loquat leaves is ursolic acid, which was recently investigated in the context of preventing muscle atrophy. The present study investigated the therapeutic potential of LE on dexamethasone‑induced muscle atrophy in rats. Daily intraperitoneal injections of dexamethasone caused muscle atrophy and evidence of muscle atrophy prevention by LE was demonstrated using various assays. In particular, dexamethasone‑induced grip strength loss was alleviated by LE and the increase in serum creatine kinase activity, a surrogate marker of muscle damage, caused by dexamethasone injection was reduced by LE. Western blot analysis and immunoprecipitation demonstrated that dexamethasone markedly increased the protein expression levels of muscle ring finger 1 (MuRF1), which causes the ubiquitination and degradation of myosin heavy chain (MyHC), and decreased the protein expression levels of MyHC as well as increased the ubiquitinated MyHC to MyHC ratio. However, LE reduced the dexamethasone‑induced protein expression levels of MuRF1 and ubiquitinated MyHC. Additional experiments revealed that LE supplementation inhibited the nuclear translocation of FoxO1 induced by dexamethasone. These findings suggested that LE prevented dexamethasone‑induced muscle atrophy by regulating the FoxO1 transcription factor and subsequently the expression of MuRF1.

  3. The time course of denervation-induced changes is similar in soleus muscles of adult and old rats.

    NARCIS (Netherlands)

    Degens, H.; Kosar, S.N.; Hopman, M.T.E.; Haan, A. de

    2008-01-01

    Muscle denervation is accompanied by atrophy and a decline in oxidative capacity. We investigated whether the time course of adaptations following denervation of the soleus muscle differs in adult (5 months old) and older adult (25 months old) rats. We denervated the soleus muscle of the left leg, w

  4. Lactate/H+ transport kinetics in rat skeletal muscle related to fibre type and changes in transport capacity

    DEFF Research Database (Denmark)

    Juel; Pilegaard

    1998-01-01

    Lactate/H+ transport kinetics were determined by means of the pH-sensitive probe BCECF in sarcolemmal giant vesicles, obtained from rat skeletal muscle, and related to variations in lactate/H+ transport capacity. Vesicle preparations were made from red and white muscles, mixed muscles, denervated...

  5. The Effect of Exercise Training on Skeletal Muscle Glucose Transorter Isoform GLUT4 Concentration in the Obese Zucker Rat

    Science.gov (United States)

    1991-05-01

    NUMBERS The Effect of Exercise Training on Skeletal Muscle Glucose Transorter Isoform GLUT4 Concentration in the Obese Zucker Rat 6. AUTHOR(S) Eric A...Zr) THE EFFECT OF EXERCISE TRAINING ON SKELETAL MUSCLE GLUCOSE TRANSPORTER ISOFORM GLUT4 CONCENTRATION IN THE OBESE ZUCKER RAT by Eric Anthony Banks...laboratory for their help. Eric A. Banks v ABSTRACT THE EFFECT OF EXERCISE TRAINING ON SKELETAL MUSCLE GLUCOSE TRANSPORTER ISOFORM GLUT4 CONCENTRATION IN

  6. [Effect of thyroidectomy on energetics of isometric muscle contraction in white rats].

    Science.gov (United States)

    Soboliev, V I; Moskalets', T V

    2007-01-01

    The effect of thyroidactomia on parameters of energetics of isometric contractions of front shin--bone muscle of white rats is studied in in situ experiments. It is shown that experimental atiriosis lengthen considerably the latent period of muscle contractions (+95%) considerably reduce (in 5.5 times) the speed of it contraction in first phase of contraction act and also considerably increase the time (+37%), which necessery for developing maximum strength of contraction. Thyroidactomia with general negative influence on ergothropic characteristics of isometric muscle contraction decrease considerably the expenditure of thermal energy on maximum strength of contraction unit (-17%) or on middle isometric tension unit (-9.3%).

  7. Effects of stretching and disuse on amino acids in muscles of rat hind limbs

    Science.gov (United States)

    Jaspers, Stephen R.; Henriksen, Erik J.; Satarug, Soisungwan; Tischler, Marc E.

    1989-01-01

    The effects of disuse and passive stretch on the concentrations of amino acids and ammonia in the unloaded soleus muscle was investigated in hindquarter-suspended (for six days by casting one foot in dorsiflexion) tail-casted rats. For a comparison with the condition of unloading, amino acids and ammonia were also measured in shortened extensor digitorum longus in the same casted limb and in denervated leg muscles. The results obtained suggest that passive stretch diminishes some of the characteristic alterations of amino acid concentrations due to unloading. This effect of stretch is considered to be due to the maintenance of muscle tension.

  8. Growth hormone mitigates loss of periosteal bone formation and muscle mass in disuse osteopenic rats

    DEFF Research Database (Denmark)

    Grubbe, M-C; Thomsen, Jesper Skovhus; Nyengaard, J R

    2014-01-01

    Growth hormone (GH) is a potent anabolic agent capable of increasing both bone and muscle mass. The aim was to investigate whether GH could counteract disuse-induced loss of bone and muscle mass in a rat model. Paralysis was induced by injecting 4 IU Botox (BTX) into the muscles of the right hind......BMD, -13%, Pmuscle mass (-69%, Pmuscle cell cross sectional area (CSA) (-73%, P... of periosteal BFR/BS (2-fold increase vs. BTX, Pmuscle mass (+29% vs. BTX, Pmuscle CSA (+11%, P=0.064). In conclusion, GH mitigates disuse...

  9. Gestational Undernourishment Modifies the Composition of Skeletal Muscle Transverse Tubule Membranes and the Mechanical Properties of Muscles in Newborn Rats

    Directory of Open Access Journals (Sweden)

    Ricardo Tonathiu Ramírez-Oseguera

    2013-10-01

    Full Text Available Backgroud/Aims: Skeletal muscle (SM constitutes more than 40% of the body weight in adulthood. Transports dietary glucose mainly through the insulin-dependent glucose transporter (Glut-4 located in the Transverse tubule membrane system (TT. The TT development ends shortly after birth. The TT membrane hosts the proteins involved in excitation-contraction coupling and glucose uptake. Glycaemic regulation through movement is a key function of fully developed skeletal muscle. In this study, we aimed to characterize the effect of gestational undernourishment (GUN in rats GLUT-4 expression and on the protein/lipid content of the TT membranes. We also examined the effect of GUN on the mechanical properties of muscles as an indication of the metabolic condition of the SM at birth. Methods: Isolated TT membrane from SM of GUN rats were used to study lipid/protein content and protein stability by differential scanning calorimetry. The effect of GUN on the SM mechanical properties was determined in isolated Extensor Digitorum Longus (EDL muscle. Results: We demonstrate that compared to control, GUN in the new-born produces; i decreases body weight; ii diminution in SM mass; iii decreases the formation of TT membranes; iv expresses TT membrane proteins with higher thermal stability. The TT membrane expression of GLUT-4 in GUN offspring was twice that of controls. The isolated EDL of GUN offspring was 20% stronger as measured by contractile force and more resistant to fatigue relative to controls. Conclusion; These results provide the first evidence of adaptive changes of the SM in new-borns exposed to severe gestational food restriction. The effects of GUN on muscle at birth are the first step toward detrimental SM metabolic function, contributing to the physiopathology of metabolic diseases in adulthood.

  10. Nitric oxide and Na,K-ATPase activity in rat skeletal muscle

    DEFF Research Database (Denmark)

    Juel, Carsten

    2016-01-01

    Aim: It has been suggested that nitric oxide (NO) stimulates the Na,K-ATPase in cardiac myocytes. Therefore, the aims of this study were to investigate whether NO increases Na,K-ATPase activity in skeletal muscle and, if that is the case, to identify the underlying mechanism. Method: The study used...... activity was depressed by oxidized glutathione. Conclusion: NO and cGMP stimulate the Na,K-ATPase in glycolytic skeletal muscle. Direct S-nitrosylation and interference with S-glutathionylation seem to be excluded. In addition, phosphorylation of phospholemman at serine 68 is not involved. Most likely...... isolated rat muscle, muscle homogenates and purified membranes as model systems. Na,K-ATPase activity was quantified from phosphate release due to ATP hydrolysis. Results: Exposure to the NO donor spermine NONOate (10 μm) increased the maximal Na,K-ATPase activity by 27% in isolated glycolytic muscles...

  11. Effects of magnetic stimulation on oxidative stress and skeletal muscle regeneration induced by mepivacaine in rat.

    Science.gov (United States)

    Jimena, I; Tasset, I; López-Martos, R; Rubio, A J; Luque, E; Montilla, P; Peña, J; Túnez, I

    2009-01-01

    We investigated the effect of magnetic field stimulation (MS) on oxidative damage and skeletal muscle injury prompted by mepivacaine injection in the anterior tibial muscle of Wistar rats. The effects of mepivacaine and MS on oxidative stress were evaluated by lipid peroxidation, GSH levels and catalase activity. Muscle regeneration was analyzed by haematoxylin-eosin stained, NADH-TR histochemical reaction, desmin immunostaining as well as by morphometric parameters such as fibers density and fiber area were evaluated. Our data revealed that mepivacaine induced oxidative stress, that MS prevents the harmful effects induced by mepivacaine and that it facilitates the regeneration process of skeletal muscle. In conclusion, the results show the ability of MS to modify skeletal muscle response to mepivacaine.

  12. Oxidative stress and peripheral skeletal muscle dysfunction in rats with emphysema

    Institute of Scientific and Technical Information of China (English)

    ZHANG Xiao-lei; PANG Bao-sen; HOU Xiao-li; WANG Jun; WANG Chen

    2010-01-01

    Background Peripheral skeletal muscle dysfunction in patients with chronic obstructive pulmonary disease (COPD)may be due to the disease per se or as a result of concomitant confounding factors. Although the mechanistic basis forthis functional impairment is uncertain, oxidative stress may play a role. The purpose of this study was to investigatewhether local oxidative stress is associated with the reduced peripheral skeletal muscle performance in rats withemphysema.Methods In situ mechanical properties of gastrocnemius were measured in Sprague-Dawley rats 5 months afterintratracheal instillation of either elastase (EMP, n=10) or normal saline (CON, n=10). Lipofuscin inclusions, myocyteapoptosis and antioxidant enzyme activities were examined in the gastrocnemius muscle.Results Lipofuscin inclusions were significantly higher in the gastrocnemius muscle of EMP compared with CON(3.2±0.4 vs. 1.7±0.4, P0.05). EMP decreased the fatigue endurance of gastrocnemius muscle (half-time to fatiguerecovery: (150.0±55.4) seconds vs. (55.2±29.3) seconds, P 0.05). A significantly positive correlation was found between the level of lipofuscininclusions and the half-time to fatigue recovery of gastrocnemius muscle in EMP (/to.664, P<0.05).Conclusion Local oxidative stress may have important functional consequences for peripheral skeletal muscle in ratswith EMP.

  13. Exercise training, glucose transporters, and glucose transport in rat skeletal muscles

    Science.gov (United States)

    Rodnick, K. J.; Henriksen, E. J.; James, D. E.; Holloszy, J. O.

    1992-01-01

    It was previously found that voluntary wheel running induces an increase in the insulin-sensitive glucose transporter, i.e., the GLUT4 isoform, in rat plantaris muscle (K. J. Rodnick, J. O. Holloszy, C. E. Mondon, and D. E. James. Diabetes 39: 1425-1429, 1990). The present study was undertaken to determine whether 1) the increase in muscle GLUT4 protein is associated with an increase in maximally stimulated glucose transport activity, 2) a conversion of type IIb to type IIa or type I muscle fibers plays a role in the increase in GLUT4 protein, and 3) an increase in the GLUT1 isoform is a component of the adaptation of muscle to endurance exercise. Five weeks of voluntary wheel running that resulted in a 33% increase in citrate synthase activity induced a 50% increase in GLUT4 protein in epitrochlearis muscles of female Sprague-Dawley rats. The rate of 2-deoxy-glucose transport maximally stimulated with insulin or insulin plus contractions was increased approximately 40% (P less than 0.05). There was no change in muscle fiber type composition, evaluated by myosin ATPase staining, in the epitrochlearis. There was also no change in GLUT1 protein concentration. We conclude that an increase in GLUT4, but not of GLUT1 protein, is a component of the adaptive response of muscle to endurance exercise and that the increase in GLUT4 protein is associated with an increased capacity for glucose transport.

  14. A novel insulin sensitizer (S15511) enhances insulin-stimulated glucose uptake in rat skeletal muscles.

    Science.gov (United States)

    Jessen, N; Selmer Buhl, E; Pold, R; Schmitz, O; Lund, S

    2008-04-01

    Type 2 diabetes is preceded by the presence of skeletal muscle insulin resistance, and drugs that increase insulin sensitivity in skeletal muscle prevent the disease. S15511 is an original compound with demonstrated effects on insulin sensitivity in animal models of insulin resistance. However, the mechanisms behind the insulin-sensitizing effect of S15511 are unknown. The aim of our study was to explore whether S15511 improves insulin sensitivity in skeletal muscles. Insulin sensitivity was assessed in skeletal muscles from S15511-treated rats by measuring intracellular insulin-signaling activity and insulin-stimulated glucose transport in isolated muscles. In addition, GLUT4 expression and glycogen levels were assessed after treatment. S15511 treatment was associated with an increase in insulin-stimulated glucose transport in type IIb fibers, while type I fibers were unaffected. The enhanced glucose transport was mirrored by a fiber type-specific increase in GLUT4 expression, while no improvement in insulin-signaling activity was observed. S15511 is a novel insulin sensitizer that is capable of improving glucose homeostasis in nondiabetic rats. The compound enhances skeletal muscle insulin sensitivity and specifically targets type IIb muscle fibers by increasing GLUT4 expression. Together these data show S15511 to be a potentially promising new drug in the treatment and prevention of type 2 diabetes.

  15. Effect of tongue position on masseter and temporalis electromyographic activity during swallowing and maximal voluntary clenching: a cross-sectional study.

    Science.gov (United States)

    Valdés, C; Astaburuaga, F; Falace, D; Ramirez, V; Manns, A

    2014-12-01

    The purpose of this study was to measure and compare the tonic electromyographic (EMG) activity of the temporalis and masseter muscles following placement of the tongue either on the palate or in the floor of the mouth during swallowing and maximal voluntary clenching (MVC). Thirty healthy dental students with natural dentition and bilateral molar support, between the ages of 18 and 22, with no prior history of oro-facial injury, or current or past pain in the jaw, mouth or tongue participated in the study. Tonic masseter and temporalis EMG activities were recorded using surface electrodes. Subjects were instructed to passively place the tongue either on the anterior hard palate or in the floor of the mouth during swallowing and MVC. At each tongue position, the resulting EMG was recorded. During swallowing, no significant difference in EMG activity was found either for the masseter (P-value = 0.1592) or the temporalis (P-value = 0.0546) muscles, regardless of the tongue position. During MVC, there was a statistically significant difference for both the masseter (P-value = 0.0016) and the temporalis (P-value = 0.0277) muscles with lower levels recorded with the tongue in the floor of the mouth. This study found that in normal, pain-free subjects, placing the tongue in the floor of the mouth significantly reduces masticatory muscle activity during MVC. Thus, it may be considered as a possible therapeutic option to decrease masticatory muscle activity; however, further research is needed in patients with oro-facial pain.

  16. Lesions of rat skeletal muscle after local block of acetylcholinesterase and neuromuscular stimulation.

    Science.gov (United States)

    Mense, S; Simons, D G; Hoheisel, U; Quenzer, B

    2003-06-01

    In skeletal muscle, a local increase of acetylcholine (ACh) in a few end plates has been hypothesized to cause the formation of contraction knots that can be found in myofascial trigger points. To test this hypothesis in rats, small amounts of an acetylcholinesterase inhibitor [diisopropylfluorophosphate (DFP)] were injected into the proximal half of the gastrocnemius muscle, and the muscle nerve was electrically stimulated for 30-60 min for induction of muscle twitches. The distal half of the muscle, which performed the same contractions, served as a control to assess the effects of the twitches without DFP. Sections of the muscle were evaluated for morphological changes in relation to the location of blocked end plates. Compared with the distal half of the muscle, the DFP-injected proximal half exhibited significantly higher numbers of abnormally contracted fibers (local contractures), torn fibers, and longitudinal stripes. DFP-injected animals in which the muscle nerve was not stimulated and that were allowed to survive for 24 h exhibited the same lesions but in smaller numbers. The data indicate that an increased concentration of ACh in a few end plates causes damage to muscle fibers. The results support the assumption that a dysfunctional end plate exhibiting increased release of ACh may be the starting point for regional abnormal contractions, which are thought to be essential for the formation of myofascial trigger points.

  17. Mild Hyperbaric Oxygen Improves Decreased Oxidative Capacity of Spinal Motoneurons Innervating the Soleus Muscle of Rats with Type 2 Diabetes.

    Science.gov (United States)

    Takemura, Ai; Ishihara, Akihiko

    2016-09-01

    Rats with type 2 diabetes exhibit decreased oxidative capacity, such as reduced oxidative enzyme activity, low-intensity staining for oxidative enzymes in fibers, and no high-oxidative type IIA fibers, in the skeletal muscle, especially in the soleus muscle. In contrast, there are no data available concerning the oxidative capacity of spinal motoneurons innervating skeletal muscle of rats with type 2 diabetes. This study examined the oxidative capacity of motoneurons innervating the soleus muscle of non-obese rats with type 2 diabetes. In addition, this study examined the effects of mild hyperbaric oxygen at 1.25 atmospheres absolute with 36 % oxygen for 10 weeks on the oxidative capacity of motoneurons innervating the soleus muscle because mild hyperbaric oxygen improves the decreased oxidative capacity of the soleus muscle in non-obese rats with type 2 diabetes. Spinal motoneurons innervating the soleus muscle were identified using nuclear yellow, a retrograde fluorescent neuronal tracer. Thereafter, the cell body sizes and succinate dehydrogenase activity of identified motoneurons were analyzed. Decreased succinate dehydrogenase activity of small-sized alpha motoneurons innervating the soleus muscle was observed in rats with type 2 diabetes. The decreased succinate dehydrogenase activity of these motoneurons was improved by mild hyperbaric oxygen. Therefore, we concluded that rats with type 2 diabetes have decreased oxidative capacity in motoneurons innervating the soleus muscle and this decreased oxidative capacity is improved by mild hyperbaric oxygen.

  18. Effect of areca on contraction of colonic muscle strips in rats

    Institute of Scientific and Technical Information of China (English)

    Dong-Ping Xie; Wei Li; Song-Yi Qu; Tian-Zhen Zheng; Ying-Li Yang; Yong-Hui Ding; Yu-Ling Wei; Lian-Bi Chen

    2002-01-01

    AIM: To investigate the effects of areca on the contractileactivity of isolated colonic muscle strips in rats andmechanism involved.METHODS: Each strip (LMPC, longitudinal muscle ofproximal colon; CMPC, circular muscle of proximal colon;LMDC, longitudinal muscle of distal colon; CMlC, circularmuscle of distal colon. ) was suspended in a tissue chambercontaining 5 mL Krebs solution (37 ℃), bubbledcontinuously with 950 mL@ L-1 O2 and 50 mL@ L-1 CO2 . Themean contractile amplitude (A), the resting tension (T),and the contractile frequency (F) were simultaneouslyrecorded on recorders.RESULTS: Arsca dose dependently increased the meancontractile amplitude, the resting tension of proximal anddistal colonic smooth muscle strips in rats ( P < 0.05). Italso partly increased the contractile frequency of colonicsmooth muscle strips in rats ( P < 0.05). The effects werepartly inhibited by atropine (the resting tension of LMPCdecreased from 0. 44 ± 0. 12 to 0. 17 ± 0.03; the restingtension of LMDC decreased from 0.71 ± 0.14 to 0.03 ± 0.01;the mean contractile amplitude of LMPC increased from -45.8 ± 7.2 to -30.5 ± 2.9; the motility index of CMDC decreasedfrom 86.6± 17.3 to 32.8 ± 9.3; P< 0.05 vs areca), but theeffects were not inhibited by hexamethonium (P> 0.05).CONCLUSION: Areca stimulated the motility of isolatedcolonic smooth muscle strips in rats. The stimulation ofareca might be relevant with M reoeptor partly.

  19. Efficacy of photobiomodulation therapy on masseter thickness and oral health-related quality of life in children with spastic cerebral palsy.

    Science.gov (United States)

    Santos, Maria Teresa Botti Rodrigues; Nascimento, Karla Santos; Carazzato, Simone; Barros, Alina Oliveira; Mendes, Fausto Medeiros; Diniz, Michele Baffi

    2017-08-01

    The study aimed to evaluate the efficacy of photobiomodulation therapy (PBMT) on bilateral masseter muscle thickness and amplitude of mouth opening in children with spastic cerebral palsy (CP), and the impact on their oral health-related quality of life (OHRQOL). Three groups were included: experimental CP group (EG: n = 26 with oral complaints), positive control CP group (PCG: n = 26 without complaints), and negative control group (NCG: n = 26 without CP). In the EG, the masseter muscles on both sides were irradiated with an infrared low-level Ga-Al-As laser (λ = 808 ± 3 nm, 120 mW) using a 3 J/cm(2) energy dose per site, with a 20 s exposure time per site (spot area: 4 mm(2); irradiance: 3 W/cm(2); energy delivery per point: 2.4 J) six times over six consecutive weeks. Masseter thickness, assessed through ultrasonography, and the amplitude of mouth opening were measured in the EG before and after six applications of PBMT and once in the PCG and NCG. The Parental-Caregiver Perception Questionnaire (P-CPQ) was used to evaluate OHRQOL. ANOVA, chi-square, t tests, and multilevel linear regression were used for statistical analysis. In the EG, the study results revealed average increments of 0.77 (0.08) millimeter in masseter thickness (P < 0.05) and 7.39 (0.58) millimeter for mouth opening (P < 0.05) and reduction in all P-CPQ domains (P < 0.001), except for social well-being. The six applications of PBMT increased masseter thickness and mouth opening amplitude and reduced the impact of spastic CP on OHRQOL.

  20. Melatonin prevents mitochondrial dysfunction and insulin resistance in rat skeletal muscle.

    Science.gov (United States)

    Teodoro, Bruno G; Baraldi, Flavia G; Sampaio, Igor H; Bomfim, Lucas H M; Queiroz, André L; Passos, Madla A; Carneiro, Everardo M; Alberici, Luciane C; Gomis, Ramon; Amaral, Fernanda G; Cipolla-Neto, José; Araújo, Michel B; Lima, Tanes; Akira Uyemura, Sérgio; Silveira, Leonardo R; Vieira, Elaine

    2014-09-01

    Melatonin has a number of beneficial metabolic actions and reduced levels of melatonin may contribute to type 2 diabetes. The present study investigated the metabolic pathways involved in the effects of melatonin on mitochondrial function and insulin resistance in rat skeletal muscle. The effect of melatonin was tested both in vitro in isolated rats skeletal muscle cells and in vivo using pinealectomized rats (PNX). Insulin resistance was induced in vitro by treating primary rat skeletal muscle cells with palmitic acid for 24 hr. Insulin-stimulated glucose uptake was reduced by palmitic acid followed by decreased phosphorylation of AKT which was prevented my melatonin. Palmitic acid reduced mitochondrial respiration, genes involved in mitochondrial biogenesis and the levels of tricarboxylic acid cycle intermediates whereas melatonin counteracted all these parameters in insulin-resistant cells. Melatonin treatment increases CAMKII and p-CREB but had no effect on p-AMPK. Silencing of CREB protein by siRNA reduced mitochondrial respiration mimicking the effect of palmitic acid and prevented melatonin-induced increase in p-AKT in palmitic acid-treated cells. PNX rats exhibited mild glucose intolerance, decreased energy expenditure and decreased p-AKT, mitochondrial respiration, and p-CREB and PGC-1 alpha levels in skeletal muscle which were restored by melatonin treatment in PNX rats. In summary, we showed that melatonin could prevent mitochondrial dysfunction and insulin resistance via activation of CREB-PGC-1 alpha pathway. Thus, the present work shows that melatonin play an important role in skeletal muscle mitochondrial function which could explain some of the beneficial effects of melatonin in insulin resistance states.

  1. Interactive effects of growth hormone and exercise on muscle mass in suspended rats

    Science.gov (United States)

    Grindeland, Richard E.; Roy, Roland R.; Edgerton, V. Reggie; Grossman, Elena J.; Mukku, Venkat R.; Jiang, Bian; Pierotti, David J.; Rudolph, Ingrid

    1994-01-01

    Measures to attenuate muscle atrophy in rats in response to simulated microgravity (hindlimb suspension (HS)) have been only partially successful. In the present study, hypophysectomized rats were in HS for 7 days, and the effects of recombinant human growth hormone (GH), exercise (Ex), or GH+Ex on the weights, protein concentrations, and fiber cross-sectional areas (CSAs) of hindlimb muscles were determined. The weights of four extensor muscles, i.e., the soleus (Sol), medial (MG) and lateral (LG) gastrocnemius, and plantaris (Plt), and one adductor, i.e., the adductor longus (AL), were decreased by 10-22% after HS. Fiber CSAs were decreased by 34% in the Sol and by 1 17% in the MG after HS. In contrast, two flexors, i.e., the tibialis anterior (TA) and extensor digitorum longus (EDL), did not atrophy. In HS rats, GH treatment alone maintained the weights of the fast extensors (MG, LG, Plt) and flexors (TA, EDL) at or above those of control rats. This effect was not observed in the slow extensor (Sol) or AL. Exercise had no significant effect on the weight of any muscle in HS rats. A combination of GH and Ex treatments yielded a significant increase in the weights of the fast extensors and in the CSA of both fast and slow fibers of the MG and significantly increased Sol weight and CSA of the slow fibers of the Sol. The AL was not responsive to either GH or Ex treatments. Protein concentrations of the Sol and MG were higher only in the Sol of Ex and GH+Ex rats. These results suggest that while GH treatment or intermittent high intensity exercise alone have a minimal effect in maintaining the mass of unloaded muscle, there is a strong interactive effect of these two treatments.

  2. Effect of HIV-1-related protein expression on cardiac and skeletal muscles from transgenic rats

    Directory of Open Access Journals (Sweden)

    Guidot David M

    2008-04-01

    Full Text Available Abstract Background Human immunodeficiency virus type 1 (HIV-1 infection and the consequent acquired immunodeficiency syndrome (AIDS has protean manifestations, including muscle wasting and cardiomyopathy, which contribute to its high morbidity. The pathogenesis of these myopathies remains partially understood, and may include nutritional deficiencies, biochemical abnormalities, inflammation, and other mechanisms due to viral infection and replication. Growing evidence has suggested that HIV-1-related proteins expressed by the host in response to viral infection, including Tat and gp120, may also be involved in the pathophysiology of AIDS, particularly in cells or tissues that are not directly infected with HIV-1. To explore the potentially independent effects of HIV-1-related proteins on heart and skeletal muscles, we used a transgenic rat model that expresses several HIV-1-related proteins (e.g., Tat, gp120, and Nef. Outcome measures included basic heart and skeletal muscle morphology, glutathione metabolism and oxidative stress, and gene expressions of atrogin-1, muscle ring finger protein-1 (MuRF-1 and Transforming Growth Factor-β1 (TGFβ1, three factors associated with muscle catabolism. Results Consistent with HIV-1 associated myopathies in humans, HIV-1 transgenic rats had increased relative heart masses, decreased relative masses of soleus, plantaris and gastrocnemius muscles, and decreased total and myosin heavy chain type-specific plantaris muscle fiber areas. In both tissues, the levels of cystine (Cyss, the oxidized form of the anti-oxidant cysteine (Cys, and Cyss:Cys ratios were significantly elevated, and cardiac tissue from HIV-1 transgenic rats had altered glutathione metabolism, all reflective of significant oxidative stress. In HIV-1 transgenic rat hearts, MuRF-1 gene expression was increased. Further, HIV-1-related protein expression also increased atrogin-1 (~14- and ~3-fold and TGFβ1 (~5-fold and ~3-fold in heart and

  3. Effects and its possible mechanism of Radix Saposhnikoviae on rat colonic smooth muscle in vitro

    Institute of Scientific and Technical Information of China (English)

    Zhenqing Liu; Tao Lü; Ping Hu; Muxin Wei

    2009-01-01

    Objective: To determine the effect of different concentrations of Radix Saposhnikoviae (RS) on the contraction of smooth muscle strips and the Ca2. mobilization of cultured smooth muscle cells of rat colon and its possible mechanism of action. Methods: Strips of rat colon longitudinal muscle were prepared and smooth muscle cells from rat colon were isolated and cultured. In the experiments, in vitro muscle strips were suspended in an organ bath and the contraction of the strips was recorded. In the cell-experiments, intracellular Ca2+ was assessed using fluorescent intensity (FI) of smooth muscle cells loaded with Fluo-4/AM, measured with a laser scanning confocal microscope and related software. Results: In the in vitro experiment, RS (0.02, 0.2, 2, 20 g/L) inhibited contraction of muscle strips in a concentration-dependent manner, and this inhibition was significant for the three higher RS concentrations (P < 0.01) for both Peak (the maximal contraction amplitude) and Area (the area under curves), Similarly, RS inhibited Ach-induced contraction. In these experiments the inhibition of the Peak values in the RS 2 and 20 g/L groups was significant (P < 0.01), as was the inhibition of the Area values in all RS groups (P < 0.05). Naloxone and propranolol did not significantly affect the inhibitory effect of RS on smooth muscle contractility, while phentolamine significantly reduced the inhibitory effect (P < 0.01). In experiments using primary smooth muscle cell cultures in Ca2+-containing buffer, the post-treatment fluorescence of cells in the RS 0.2, 2 and 20 g/L groups differed significantly from pre-treatment values (P < 0.05), and the percent inhibition of fluorescence in the RS 2 g/L and 20 g/L groups was significant (P < 0.01). However, in Ca2+-free buffer, FS had no significant effect on cell fluorescence. Conclusion: RS inhibited both the spontaneous and Ach-stimulated contraction of rat colonic smooth muscle strips. This RS effect appeared to involve a

  4. Induction of Muscle Hypertrophy in Rats through Low Intensity Eccentric Contraction

    OpenAIRE

    Tsumiyama, Wakako; Oki, Sadaaki; Takamiya, Naomi; Umei, Namiko; Shimizu, Michele Eisemann; Ono, Takeya; Otsuka, Akira

    2014-01-01

    [Purpose] The purpose of this study was to examine whether a low intensity exercise using an eccentric contraction would result in skeletal muscle hypertrophy in rats. [Subjects and Methods] Eighteen female Wistar rats were used in this study. The rats were randomly divided into three groups. The control group performed no exercise. The level group ran on a treadmill on a 0° incline. The downhill group ran on a treadmill on a −16° incline. The two exercise groups ran on a treadmill at 16 m/mi...

  5. Histomorphometric analysis of the response of rat skeletal muscle to swimming, immobilization and rehabilitation

    Directory of Open Access Journals (Sweden)

    C.C.F. Nascimento

    2008-09-01

    Full Text Available The objective of the present study was to determine to what extent, if any, swimming training applied before immobilization in a cast interferes with the rehabilitation process in rat muscles. Female Wistar rats, mean weight 260.52 ± 16.26 g, were divided into 4 groups of 6 rats each: control, 6 weeks under baseline conditions; trained, swimming training for 6 weeks; trained-immobilized, swimming training for 6 weeks and then immobilized for 1 week; trained-immobilized-rehabilitated, swimming training for 6 weeks, immobilized for 1 week and then remobilized with swimming for 2 weeks. The animals were then sacrificed and the soleus and tibialis anterior muscles were dissected, frozen in liquid nitrogen and processed histochemically (H&E and mATPase. Data were analyzed statistically by the mixed effects linear model (P < 0.05. Cytoarchitectural changes such as degenerative characteristics in the immobilized group and regenerative characteristics such as centralized nucleus, fiber size variation and cell fragmentation in the groups submitted to swimming were more significant in the soleus muscle. The diameters of the lesser soleus type 1 and type 2A fibers were significantly reduced in the trained-immobilized group compared to the trained group (P < 0.001. In the tibialis anterior, there was an increase in the number of type 2B fibers and a reduction in type 2A fibers when trained-immobilized rats were compared to trained rats (P < 0.001. In trained-immobilized-rehabilitated rats, there was a reduction in type 2B fibers and an increase in type 2A fibers compared to trained-immobilized rats (P < 0.009. We concluded that swimming training did not minimize the deleterious effects of immobilization on the muscles studied and that remobilization did not favor tissue re-adaptation.

  6. The Dilator Naris Muscle as a Reporter of Facial Nerve Regeneration in a Rat Model

    NARCIS (Netherlands)

    Weinberg, J.S.; Kleiss, I.J.; Knox, C.J.; Heaton, J.T.; Hadlock, T.A.

    2016-01-01

    OBJECTIVE: Many investigators study facial nerve regeneration using the rat whisker pad model, although widely standardized outcomes measures of facial nerve regeneration in the rodent have not yet been developed. The intrinsic whisker pad "sling" muscles producing whisker protraction, situated at t

  7. Effect of Tongue Exercise on Protrusive Force and Muscle Fiber Area in Aging Rats

    Science.gov (United States)

    Connor, Nadine P.; Russell, John A.; Wang, Hao; Jackson, Michelle A.; Mann, Laura; Kluender, Keith

    2009-01-01

    Purpose: Age-related changes in tongue function may contribute to dysphagia in elderly people. The authors' purpose was to investigate whether aged rats that have undergone tongue exercise would manifest increased protrusive tongue forces and increased genioglossus (GG) muscle fiber cross-sectional areas. Method: Forty-eight young adult,…

  8. CHANGES IN THE ELECTROMYOGRAM OF 2 MAJOR HINDLIMB MUSCLES DURING LOCOMOTOR DEVELOPMENT IN THE RAT

    NARCIS (Netherlands)

    WESTERGA, J; GRAMSBERGEN, A

    1993-01-01

    The development of the electromyogram (EMG) of tibialis anterior (TA) and medial gastrocnemius (GM) during locomotion was studied in normal rats from the onset of quadruped walking (postnatal day 10, P10) until P42. The objectives were to relate signal properties of the EMG and coordination of muscl

  9. Formation of hydrogen peroxide and nitric oxide in rat skeletal muscle cells during contractions

    DEFF Research Database (Denmark)

    Silveira, Leonardo R.; Pereira-Da-Silva, Lucia; Juel, Carsten

    2003-01-01

    We examined intra- and extracellular H(2)O(2) and NO formation during contractions in primary rat skeletal muscle cell culture. The fluorescent probes DCFH-DA/DCFH (2,7-dichlorofluorescein-diacetate/2,7-dichlorofluorescein) and DAF-2-DA/DAF-2 (4,5-diaminofluorescein-diacetate/4,5-diaminofluoresce...

  10. Reinnervation of muscles after transection of the sciatic nerve in adult rats

    NARCIS (Netherlands)

    Ijkema-Paassen, J; Meek, MF; Gramsbergen, A

    2002-01-01

    Functional recovery after transection of the sciatic nerve in adult rats is poor, probably because of abnormalities in reinnervation. Denervation and reinnervation patterns were studied morphologically in the lateral gastrocnemius (LGC), tibialis anterior (TA), and soleus (SOL) muscles for 21 weeks

  11. Neurotrophin-3 mRNA expression in rat intrafusal muscle fibres after denervation and reinnervation

    NARCIS (Netherlands)

    Copray, JCVM; Brouwer, N

    1997-01-01

    We have studied the regulation of the expression of neurotrophin-3 (NT-3) mRNA in neonatal and adult rat muscle spindles after denervation and after denervation followed by reinnervation. Denervation of the intrafusal fibres did not result in an upregulation of the NT-3 mRNA expression but decreased

  12. BRAIN-STEM INFLUENCES ON BICEPS REFLEX ACTIVITY AND MUSCLE TONE IN THE ANESTHETIZED RAT

    NARCIS (Netherlands)

    JUCH, PJW; SCHAAFSMA, A; VANWILLIGEN, JD

    1992-01-01

    This study analyzes the effect of electrical stimulation of the locus coeruleus (LC) and adjacent brainstem structures on the tonic reflex (TVR), the tonic stretch reflex (TSR) and on muscle tone (MT) in anaesthetized rat. Increases in TVR. TSR and MT of the m. biceps were evoked from regions

  13. Effect of Tongue Exercise on Protrusive Force and Muscle Fiber Area in Aging Rats

    Science.gov (United States)

    Connor, Nadine P.; Russell, John A.; Wang, Hao; Jackson, Michelle A.; Mann, Laura; Kluender, Keith

    2009-01-01

    Purpose: Age-related changes in tongue function may contribute to dysphagia in elderly people. The authors' purpose was to investigate whether aged rats that have undergone tongue exercise would manifest increased protrusive tongue forces and increased genioglossus (GG) muscle fiber cross-sectional areas. Method: Forty-eight young adult,…

  14. Effect of Ferula hermonis root extract on rat skeletal muscle adaptation to exercise.

    Science.gov (United States)

    Allouh, Mohammed Z

    2011-12-01

    Ferula hermonis Boiss. is an aphrodisiac plant that grows in the Mediterranean region. It has been reported that treatment with acetonic extract from the root of this plant acutely increases serum testosterone in the rat. This study investigated the effects of F. hermonis extract alone or combined with exercise on rat skeletal muscle fibers. Adult male rats were divided into four groups: control-sedentary (CS) that had no treatment or exercise; ferula-sedentary (FS) that was orally treated with ferula extract at a dose of 60 mg/kg/rat every other day over a period of 20 d; control-exercised (CE) that was trained by swimming for 40 min every other day; and ferula-exercised (FE) that received ferula and performed exercise. At the end of experiments, the fiber diameter and number of muscle nuclei of tibialis anterior were measured by using immunofluorescent techniques and software analyses. The FE group showed significant increases in muscle weight, fiber size and nuclear number compared with the other groups. However, no significant changes in the aforementioned parameters were found among the CS, FS and CE groups. Ferula treatment and exercise were additive to each other. In conclusion, short-term exercise combined with administration of F. hermonis extract was more effective in enhancing the growth of skeletal muscle fibers than exercise alone.

  15. Soy germ protein concentrate diet decreased body fat weight and increased hindlimb muscle weight in rats.

    Science.gov (United States)

    Kataoka, Hisashi; Saito, Sanshiro; Itoh, Atsushi; Matsuo, Tatsuhiro

    2012-01-01

    The purpose of this study was to investigate the effects of soy germ protein intake on body composition. Wistar rats were fed experimental diets for 16 weeks. These consisted of soy germ protein, soy protein, or casein. Abdominal adipose tissue weights significantly lower and hindlimb muscle weights were significantly higher in the soy germ protein group than in the casein group.

  16. Effects of One Resistance Exercise Session on Vascular Smooth Muscle of Hypertensive Rats

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Tharciano Luiz Teixeira Braga da; Mota, Marcelo Mendonça; Fontes, Milene Tavares; Araújo, João Eliakim dos Santos; Carvalho, Vitor Oliveira; Bonjardim, Leonardo Rigoldi; Santos, Márcio Roberto Viana, E-mail: marciorvsantos@bol.com.br [Universidade Federal de Sergipe, Universidade de São Paulo (Brazil)

    2015-08-15

    Hypertension is a public health problem and increases the incidence of cardiovascular diseases. To evaluate the effects of a resistance exercise session on the contractile and relaxing mechanisms of vascular smooth muscle in mesenteric arteries of N{sup G}-nitro L-arginine methyl ester (L-NAME)-induced hypertensive rats. Wistar rats were divided into three groups: control (C), hypertensive (H), and exercised hypertensive (EH). Hypertension was induced by administration of 20 mg/kg of L-NAME for 7 days prior to experimental protocols. The resistance exercise protocol consisted of 10 sets of 10 repetitions and intensity of 40% of one repetition maximum. The reactivity of vascular smooth muscle was evaluated by concentration‑response curves to phenylephrine (PHEN), potassium chloride (KCl) and sodium nitroprusside (SNP). Rats treated with L-NAME showed an increase (p < 0.001) in systolic blood pressure (SBP), diastolic blood pressure (DBP) and mean arterial pressure (MAP) compared to the initial period of induction. No difference in PHEN sensitivity was observed between groups H and EH. Acute resistance exercise reduced (p < 0.001) the contractile response induced by KCl at concentrations of 40 and 60 mM in group EH. Greater (p < 0.01) smooth muscle sensitivity to NPS was observed in group EH as compared to group H. One resistance exercise session reduces the contractile response induced by KCl in addition to increasing the sensitivity of smooth muscle to NO in mesenteric arteries of hypertensive rats.

  17. Effect of training and detraining on skeletal muscle glucose transporter (GLUT4) content in rats.

    Science.gov (United States)

    Neufer, P D; Shinebarger, M H; Dohm, G L

    1992-09-01

    The aim of the present study was to examine the effects of treadmill exercise training and detraining on the skeletal muscle fiber type specific expression of the insulin-regulated glucose transporter protein (GLUT4) in rats. GLUT4 protein content was determined by Western and dot-blot analysis, using a polyclonal antibody raised against the carboxy-terminal peptide. Rats were sacrificed 24 h after the last training session. There were no significant changes in muscle GLUT4 after 1 day or 1 week of training. Six weeks of training increased GLUT4 protein content 1.4- to 1.7-fold (p < 0.05) over controls in the soleus and red vastus lateralis, whereas no significant change was evident in the white vastus lateralis muscle. GLUT4 protein content in both soleus and red vastus lateralis muscle returned to near control values after 7 days of detraining. Similar to GLUT4, citrate synthase activity showed no change after 1 day or 1 week of training, increased 1.8-fold over controls after 6 weeks of training, but returned to control values after 7 days detraining. These findings demonstrate that muscle GLUT4 protein is increased in rats with as little as 6 weeks of treadmill exercise training but that the adaptation is lost within 1 week of detraining. It is suggested that expression of the GLUT4 protein is coordinated with the well-documented adaptations in oxidative enzyme activity with endurance training and detraining.

  18. Targeted gene transfer into rat facial muscles by nanosecond pulsed laser-induced stress waves

    Science.gov (United States)

    Kurita, Akihiro; Matsunobu, Takeshi; Satoh, Yasushi; Ando, Takahiro; Sato, Shunichi; Obara, Minoru; Shiotani, Akihiro

    2011-09-01

    We investigate the feasibility of using nanosecond pulsed laser-induced stress waves (LISWs) for gene transfer into rat facial muscles. LISWs are generated by irradiating a black natural rubber disk placed on the target tissue with nanosecond pulsed laser light from the second harmonics (532 nm) of a Q-switched Nd:YAG laser, which is widely used in head and neck surgery and proven to be safe. After injection of plasmid deoxyribose nucleic acid (DNA) coding for Lac Z into rat facial muscles, pulsed laser is used to irradiate the laser target on the skin surface without incision or exposure of muscles. Lac Z expression is detected by X-gal staining of excised rat facial skin and muscles. Strong Lac Z expression is observed seven days after gene transfer, and sustained for up to 14 days. Gene transfer is achieved in facial muscles several millimeters deep from the surface. Gene expression is localized to the tissue exposed to LISWs. No tissue damage from LISWs is observed. LISW is a promising nonviral target gene transfer method because of its high spatial controllability, easy applicability, and minimal invasiveness. Gene transfer using LISW to produce therapeutic proteins such as growth factors could be used to treat nerve injury and paralysis.

  19. Cryotherapy reduces skeletal muscle damage after ischemia/reperfusion in rats.

    Science.gov (United States)

    Puntel, Gustavo O; Carvalho, Nélson R; Dobrachinski, Fernando; Salgueiro, Andréia C F; Puntel, Robson L; Folmer, Vanderlei; Barbosa, Nilda B V; Royes, Luiz F F; Rocha, João Batista T; Soares, Félix A A

    2013-02-01

    The aim of this study was to analyze the effects of cryotherapy on the biochemical and morphological changes in ischemic and reperfused (I/R) gastrocnemius muscle of rats. Forty male Wistar rats were divided into control and I/R groups, and divided based on whether or not the rats were submitted to cryotherapy. Following the reperfusion period, biochemical and morphological analyses were performed. Following cryotherapy, a reduction in thiobarbituric acid-reactive substances and dichlorofluorescein oxidation levels were observed in I/R muscle. Cryotherapy in I/R muscle also minimized effects such as decreased cellular viability, levels of non-protein thiols and calcium ATPase activity as well as increased catalase activity. Cryotherapy also limited mitochondrial dysfunction and decreased the presence of neutrophils in I/R muscle, an effect that was corroborated by reduced myeloperoxidase activity in I/R muscle treated with cryotherapy. The effects of cryotherapy are associated with a reduction in the intensity of the inflammatory response and also with a decrease in mitochondrial dysfunction.

  20. Branched-chain amino acid metabolism in rat muscle: abnormal regulation in acidosis

    Energy Technology Data Exchange (ETDEWEB)

    May, R.C.; Hara, Y.; Kelly, R.A.; Block, K.P.; Buse, M.G.; Mitch, W.E.

    1987-06-01

    Branched-chain amino acid (BCAA) metabolism is frequently abnormal in pathological conditions accompanied by chronic metabolic acidosis. To study how metabolic acidosis affects BCAA metabolism in muscle, rats were gavage fed a 14% protein diet with or without 4 mmol NH/sub 4/Cl x 100 g body wt/sup -1/ x day/sup -1/. Epitrochlearis muscles were incubated with L-(1-/sup 14/C)-valine and L-(1-/sup 14/C)leucine, and rates of decarboxylation, net transamination, and incorporation into muscle protein were measured. Plasma and muscle BCAA levels were lower in acidotic rats. Rates of valine and leucine decarboxylation and net transamination were higher in muscles from acidotic rats; these differences were associated with a 79% increase in the total activity of branched-chain ..cap alpha..-keto acid dehydrogenase and a 146% increase in the activated form of the enzyme. They conclude that acidosis affects the regulation of BCAA metabolism by enhancing flux through the transaminase and by directly stimulating oxidative catabolism through activation of branched-chain ..cap alpha..-keto acid dehydrogenase.

  1. Repeated bouts of fast velocity eccentric contractions induce atrophy of gastrocnemius muscle in rats.

    Science.gov (United States)

    Ochi, Eisuke; Nosaka, Kazunori; Tsutaki, Arata; Kouzaki, Karina; Nakazato, Koichi

    2015-10-01

    One bout of exercise consisting of fast velocity eccentric contractions has been shown to increase muscle protein degradation in rats. The present study tested the hypothesis that muscle atrophy would be induced after four bouts of fast velocity eccentric contractions, but not after four bouts of slow velocity eccentric contractions. Male Wistar rats were randomly placed into 3 groups; fast (180°/s) velocity (180EC, n = 7), slow (30°/s) velocity eccentric exercise (30EC, n = 7), or sham-treatment group (control, n = 7). The 180EC and 30EC groups received 4 sessions of 4 sets of 5 eccentric contractions of triceps surae muscles by extending the ankle joint during evoked electrical stimulation of the muscles, and the control group had torque measures, every 2 days, and all rats were sacrificed 1 day after the fourth session. Medial and lateral gastrocnemius wet mass were 4-6 % smaller, cross-sectional area of medial gastrocnemius was 6-7% smaller, and isometric tetanic torque of triceps surae muscles was 36 % smaller (p contractions.

  2. The effect of a single dose of morphine on muscle fatigue indices in male rats

    Directory of Open Access Journals (Sweden)

    Sedigheh Amiresmaili

    2016-09-01

    Full Text Available Background and Aim: Endogenous opioids and addictive opiate drugs change many body functions. . Previous studies have referred to the effects of morphine on smooth and pulmonary muscles ., but the  effects of opioids on skeletal muscles is not known well. Thus, the current study aimed at assessing the effect of a single dose of morphine on muscle fatigue in male rats. Materials and Methods: In this experimental study, 40 male Wistar rats weighing 220-270 g were randomly divided into four equal groups: control (the mice were kept in their cages and received food and water, morphine receiving group, fatigue group (the mice in this group were kept running on  a treadmill . for120 minutes at a rate of 20 meters per minute, and morphine plus fatigue group. At the end of the experiments, blood samples were obtained from the corner of their eyes and were sent to the laboratory for measurement of muscle fatigue indexes including lactate dehydrogenase (LDH and creatine phosphokinase (CPK. Results: Administration of morphine to the fatigue group decreased running time compared with the control group (P=0.009. Furthermore, administration of morphine to the fatigue group significantly increased serum levels of LDH (P=0.009 and CPK (P=0.008. Conclusion: The present study showed that administration of a single dose of morphine in rats increases muscle fatigue biomarkers (LDH, CPK.

  3. Influence of creatine supplementation on indicators of glucose metabolism in skeletal muscle of exercised rats

    Directory of Open Access Journals (Sweden)

    Michel Barbosa de Araújo

    2013-12-01

    Full Text Available The purpose of this study was to evaluate the effect of creatine supplementation in the diet on indicators of glucose metabolism in skeletal muscle of exercised rats. Forty Wistar adult rats were distributed into four groups for eight weeks: 1 Control: sedentary rats that received balanced diet; 2 Creatine control: sedentary rats that received supplementation of 2% creatine in the balanced diet; 3 Trained: rats that ran on a treadmill at the Maximal Lactate Steady State and received balanced diet; and 4 Supplemented-trained: rats that ran on a treadmill at the Maximal Lactate Steady State and received creatine supplementation (2% in the balanced diet. The hydric intake increased and the body weight gain decreased in the supplemented-trained group. In the soleus muscle, the glucose oxidation increased in both supplemented groups. The production of lactate and glycemia during glucose tolerance test decreased in the supplemented-trained group. Creatine supplementation in conjunction with exercise training improved muscular glycidic metabolism of rats.

  4. Fish protein intake induces fast-muscle hypertrophy and reduces liver lipids and serum glucose levels in rats.

    Science.gov (United States)

    Kawabata, Fuminori; Mizushige, Takafumi; Uozumi, Keisuke; Hayamizu, Kohsuke; Han, Li; Tsuji, Tomoko; Kishida, Taro

    2015-01-01

    In our previous study, fish protein was proven to reduce serum lipids and body fat accumulation by skeletal muscle hypertrophy and enhancing basal energy expenditure in rats. In the present study, we examined the precise effects of fish protein intake on different skeletal muscle fiber types and metabolic gene expression of the muscle. Fish protein increased fast-twitch muscle weight, reduced liver triglycerides and serum glucose levels, compared with the casein diet after 6 or 8 weeks of feeding. Furthermore, fish protein upregulated the gene expressions of a fast-twitch muscle-type marker and a glucose transporter in the muscle. These results suggest that fish protein induces fast-muscle hypertrophy, and the enhancement of basal energy expenditure by muscle hypertrophy and the increase in muscle glucose uptake reduced liver lipids and serum glucose levels. The present results also imply that fish protein intake causes a slow-to-fast shift in muscle fiber type.

  5. Atrophy and growth failure of rat hindlimb muscles in tail-cast suspension

    Science.gov (United States)

    Jaspers, S. R.; Tischler, M. E.

    1984-01-01

    The primary objective of the present study is related to an evaluation of a modified tail-cast suspension model as a means of identifying metabolic factors which control or are associated with muscle atrophy and growth failure. Two different control conditions (normal and tail-casted weight bearing) were studied to determine the appropriate control for tail-cast suspension. A description is presented of a model which is most useful for studying atrophy of hindlimb muscles under certain conditions. Female Sprague-Dawley rats were employed in the experiments. Attention is given to growth rate and urinary excretion of urea and ammonia in different types of rats, the relationship between body weight and skeletal muscle weight, and the relationship between animal body weight and rates of protein synthesis and protein degradation.

  6. Atrophy and growth failure of rat hindlimb muscles in tail-cast suspension

    Science.gov (United States)

    Jaspers, S. R.; Tischler, M. E.

    1984-01-01

    The primary objective of the present study is related to an evaluation of a modified tail-cast suspension model as a means of identifying metabolic factors which control or are associated with muscle atrophy and growth failure. Two different control conditions (normal and tail-casted weight bearing) were studied to determine the appropriate control for tail-cast suspension. A description is presented of a model which is most useful for studying atrophy of hindlimb muscles under certain conditions. Female Sprague-Dawley rats were employed in the experiments. Attention is given to growth rate and urinary excretion of urea and ammonia in different types of rats, the relationship between body weight and skeletal muscle weight, and the relationship between animal body weight and rates of protein synthesis and protein degradation.

  7. Succinylcholine-induced hyperkalemia in the rat following radiation injury to muscle

    Energy Technology Data Exchange (ETDEWEB)

    Cairoli, V.J.; Ivankovich, A.D.; Vucicevic, D.; Patel, K.

    1982-02-01

    During anesthetic preparation of a patient who had received routine radiation therapy for sarcoma of the leg, cardiac collapse occurred following succinylcholine (SCh) administration. Experiments were designed to test the hypothesis that radiation injury to muscle might cause increased sensitivity to SCh similar to that reported in patients with muscle trauma, severe burns, and lesions causing muscle denervation. Venous plasma potassium levels and arterial blood gas tensions were measured in rats after they were given SCh (3 mg/kg) at various times following /sup 60/Co irradiation of the hind legs. Nonirradiated rats responded to SCh with a slight but statistically significant increase in plasma K+. Rats subjected to high levels of radiation (10,000 to 20,000 R) and given SCh 4 to 7 days later responded in the same way as the control rats. Plasma K+ levels in rats exposed to a fractionated irradiated dosage (2500 R given twice with a 1-week interval) followed by SCh 1 week later were similar to those in the control group, but when SCh was given 2 weeks later (3 weeks after initial irradiation) there was a marked elevation of plasma K+, from 3.6 to 7.7 meq/L, a statistically significant increase.

  8. Succinylcholine-induced hyperkalemia in the rat following radiation injury to muscle. [60Co

    Energy Technology Data Exchange (ETDEWEB)

    Cairoli, V.J.; Ivankovich, A.D.; Vucicevic, D.; Patel, K.

    1982-02-01

    During anesthetic preparation of a patient who had received routine radiation therapy of sarcoma of the leg, cardiac collapse occurred following succinylcholine (SCh) administration. Experiments were designed to test the hypothesis that radiation injury to muscle might cause increased sensitivity to SCh similar to that reported in patients with muscle trauma, severe burns, and lesions causing muscle denervation. Venous plasma potassium levels and arterial blood gas tensions were measured in rats after they were given SCh (3 mg/kg) at various times following 60Co irradiation of the hind legs. Nonirradiated rats responded to SCh with a slight but statistically significant increase in plasma K+. Rats subjected to high levels of radiation (10,000 to 20,000 R) and given SCh 4 to 7 days later responded in the same way as the control rats. Plasma K+ levels in rats exposed to a fractionated irradiated dosage (25000 R given twice with a 1-week interval) followed by SCh 1 week later were similar to those in the control group, but when SCh was given 2 weeks later (3 weeks after initial irradiation) there was a marked elevation of plasma K+, from 3.6 to 7.7 meq/L, a statistically significant increase.

  9. Receptor Expression in Rat Skeletal Muscle Cell Cultures

    Science.gov (United States)

    Young, Ronald B.

    1996-01-01

    One on the most persistent problems with long-term space flight is atrophy of skeletal muscles. Skeletal muscle is unique as a tissue in the body in that its ability to undergo atrophy or hypertrophy is controlled exclusively by cues from the extracellular environment. The mechanism of communication between muscle cells and their environment is through a group of membrane-bound and soluble receptors, each of which carries out unique, but often interrelated, functions. The primary receptors include acetyl choline receptors, beta-adrenergic receptors, glucocorticoid receptors, insulin receptors, growth hormone (i.e., somatotropin) receptors, insulin-like growth factor receptors, and steroid receptors. This project has been initiated to develop an integrated approach toward muscle atrophy and hypertrophy that takes into account information on the populations of the entire group of receptors (and their respective hormone concentrations), and it is hypothesized that this information can form the basis for a predictive computer model for muscle atrophy and hypertrophy. The conceptual basis for this project is illustrated in the figure below. The individual receptors are shown as membrane-bound, with the exception of the glucocorticoid receptor which is a soluble intracellular receptor. Each of these receptors has an extracellular signalling component (e.g., innervation, glucocorticoids, epinephrine, etc.), and following the interaction of the extracellular component with the receptor itself, an intracellular signal is generated. Each of these intracellular signals is unique in its own way; however, they are often interrelated.

  10. Effects of botulinum toxin A injection and exercise on the growth of juvenile rat gastrocnemius muscle.

    Science.gov (United States)

    Chen, Chen-Ming; Stott, N Susan; Smith, Heather K

    2002-10-01

    Botulinum toxin A (Btx) injections and supervised exercise are often used concurrently to treat calf muscle spasticity in children. This study has analyzed the early effects of Btx-induced paralysis and increased activity by voluntary wheel running on cell growth-related processes in juvenile rat gastrocnemius muscle. Btx injection at 29 days of age prevented the normal increases in wet mass (50%) and fiber cross-sectional area (34%) seen by 36 days of age in control rats. Btx-injected vs. contralateral muscles had 22% fewer myonuclei per fiber length but greater than twofold the number of MyoD-positive nuclei at 36 days of age. The accretion of 5-bromo-2'-deoxyuridine-labeled newly produced myonuclei did not differ between limbs. Voluntary exercise during the 7 days increased the mass (18%) and fiber size (23%) of Btx-injected and contralateral muscles but did not affect any other variable. Thus Btx injection and exercise had early effects on muscle and fiber size without consistently associated changes in myonuclear production or number. This suggests the presence of noncontractile activity-dependent, growth-promoting cytoplasmic events in juvenile muscle.

  11. Effect of the Lipoxygenase Inhibitor Baicalein on Muscles in Ovariectomized Rats

    Directory of Open Access Journals (Sweden)

    D. Saul

    2016-01-01

    Full Text Available Sarcopenia, a loss of muscle mass accompanying osteoporosis, leads to falls and fall-related injuries. Baicalein, as a phytochemical agent, has an antioxidative and anti-inflammatory effect in muscle. In this study, sixty-one female Sprague Dawley rats were divided into five groups: four groups were ovariectomized (OVX and one control group was nonovariectomized (NON-OVX. Eight weeks after ovariectomy, three disparate concentrations (1 mg/kg body weight (BW, 10 mg/kg BW, and 100 mg/kg BW of baicalein were applied subcutaneously daily in three OVX groups. Mm. soleus, gastrocnemius, and longissimus were extracted; their diameter, area, relation to body, and muscle weights as well as number of capillaries per fibre were recorded. In Mm. soleus and gastrocnemius, the baicalein effect (increasing number of capillaries per fibre was proportional to the dose applied. The fibre diameters and area under baicalein treatment were significantly greater compared to OVX and NON-OVX groups. In M. longissimus, we observed a shift to type IIa fibres. Serum creatine kinase levels were significantly lower in highest baicalein concentration group. We conclude that baicalein can stimulate angiogenesis, though not fibre type-specific, in skeletal muscle and reduce the estrogen-related loss of fibre diameter and area in the skeletal muscle in rats. Therefore, a protective effect of baicalein on muscle cells can be assumed.

  12. Acute resistance exercise reduces increased gene expression in muscle atrophy of ovariectomised arthritic rats

    Directory of Open Access Journals (Sweden)

    Roberto Furlanetto Jr

    2017-02-01

    Full Text Available Objective: We studied the effect of resistance exercise (RE on mRNA levels of atrogin-1, MuRF-1, and myostatin in the gastrocnemius muscle of arthritic rats after loss of ovarian function (LOF. Material and methods : Thirty female Wistar rats (nine weeks old, 195.3 ±17.4 grams were randomly allocated into five groups: control group (CT-Sham; n = 6; group with rheumatoid arthritis (RA; n = 6; group with rheumatoid arthritis subjected to RE (RAEX; n = 6; ovariectomy group with rheumatoid arthritis (RAOV; n = 6; and an ovariectomy group with rheumatoid arthritis subjected to RE (RAOVEX; n = 6. After 15 days of intra-articular injections with Met-BSA the animals were subjected to RE and six hours after workout were euthanised. Results : The rheumatoid arthritis provoked reduction in the cross-sectional area (CSA of muscle fibres, but the CSA was lower in the RAOV when compared to the RA groups. Skeletal muscle atrogin-1 mRNA level was increased in arthritic rats (RA and RAOV, but the atrogin-1 level was higher in RAOV group when compared to other arthritic groups. The Muscle MuRF-1 mRNA level was also increased in the RAOV group. The increased atrogin-1 and MuRF-1 mRNA levels were lower in the RAOVEX group than in the RAOV group. The myostatin mRNA level was similar in all groups, except for the RAOVEX group, in which it was lower than the other groups. Conclusions : LOF results in increased loss of skeletal muscle-related ubiquitin ligases (atrogin-1 and MuRF-1. However, the RE reduces the atrogin-1, MuRF-1, and myostatin mRNA levels in muscle of arthritic rats affected by LOF.

  13. Exercise at simulated high altitude facilitates the increase in capillarity in skeletal muscle of rats

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    AIM: To study the changes in capillarity of skeletal muscle during acclimation to high altitude, and explore the effects of a certain extent physical activity under hypoxia on capillary formation and the role of vascular endothelial growth factor (VEGF) in this process. METHODS: 48 Wistar rats were divided into 3 groups: Ⅰ normoxic control; Ⅱ hypoxia and Ⅲ hypoxia+exercise. Rats of Ⅱ and Ⅲ groups were subjected to hypobaric hypoxia for 5 weeks (23 h/d). They were first brought to simulated 4 000 m altitude, where rats of the Ⅲgroup were forced to swim for 1 h/d (6 d/week). Then the animals were ascent to 5 000 m. Biomicrosphere method was used to determine blood flow of skeletal muscle. The mean fiber cross-sectional area (FCSA), capillary density (CD) and capillary/fiber ratio (C/F) of red portion of the lateral head of the gastrocneminus were assayed by myofibrillar ATPase histochemistry. VEGF and its receptor KDR were assayed with immunohistochemistry method.RESULTS: By comparison with the normoxic control, 5-week hypoxic exposure resulted in a decrease in cross-sectional area of skeletal muscle fiber and an increase in CD, but the C/F remained unchanged. The blood supply to the gastrocnemius was not changed. After 5-week-exercise at high altitude, the muscle fibers did not undergo atrophy. CD, C/F, and the blood flow at rest increased significantly. VEGF protein was found primarily in the matrix between muscle fibers; KDR were shown mainly in endothelial cells of capillary. VEGF was more strongly stained in the skeletal muscle of hypoxia-exercise rats.CONCLUSION: Hypoxia itself can not induce neovascularization. While exercise during hypoxic exposure can lead to capillary formation. VEGF and KDR may play roles in it. New capillary formation benefits the blood supply, oxygen delivery and working performance at high altitude.

  14. Changes in nitric oxide and free radical levels in rat gastrocnemius muscle during contraction and fatigue.

    Science.gov (United States)

    Ibrahim, Mariam Y; Ashour, Osama M

    2011-12-01

    1. The ratio of nitric oxide (NO) to free radicals is critical during skeletal muscle contraction. Changes in this ratio have been suggested to play a role in muscle fatigue. 2. The aim of the present study was to investigate the changes in NO and free radicals during tetanic and subtetanic contraction and fatigue in the gastrocnemius muscle of adult male Wistar rats. 3. Rats were subjected to either low- or high-frequency stimulation (10 and 100 Hz, respectively) of the right gastrocnemius muscle. Both groups were further subdivided into untreated (0.9% NaCl solution), N(G) -nitro-L-arginine methyl ester (L-NAME)-treated and reduced glutathione (GSH)-treated groups. Rats were administered their treatments intraperitoneally 30 min prior to electrical stimulation. 4. Levels of both NO and lipid peroxides increased significantly during peak force contraction for either type of contractions, with a more significant response during subtetanic contraction. Treatment with L-NAME significantly reduced the maximal force and this effect was more marked in the low frequency-stimulated group. Although peroxides levels were reduced by GSH, it had no significant effect on force production. In L-NAME-treated rats, the onset of 50% fatigue was accelerated with a significant increase in peroxides levels, whereas the opposite effects were observed after GSH treatment. 5. Current results reflect the importance of endogenous NO, as an anti-oxidant, in aiding muscle performance by overcoming oxidative stress during fatigue. They provide a possible explanation as to why patients with myopathies like Duchenne muscular dystrophy, in which dystrophin is lacking suffer from muscle weakness and fatigue easily.

  15. Acute resistance exercise reduces increased gene expression in muscle atrophy of ovariectomised arthritic rats

    Science.gov (United States)

    Furlanetto, Roberto; de Paula Souza, Aletéia; de Oliveira, Anselmo Alves; Nunes, Paulo Ricardo Prado; Michelin, Márcia Antoniazi; Chica, Javier Emilio Lazo; Murta, Eddie Fernando Candido

    2017-01-01

    Objective We studied the effect of resistance exercise (RE) on mRNA levels of atrogin-1, MuRF-1, and myostatin in the gastrocnemius muscle of arthritic rats after loss of ovarian function (LOF). Material and methods Thirty female Wistar rats (nine weeks old, 195.3 ±17.4 grams) were randomly allocated into five groups: control group (CT-Sham; n = 6); group with rheumatoid arthritis (RA; n = 6); group with rheumatoid arthritis subjected to RE (RAEX; n = 6); ovariectomy group with rheumatoid arthritis (RAOV; n = 6); and an ovariectomy group with rheumatoid arthritis subjected to RE (RAOVEX; n = 6). After 15 days of intra-articular injections with Met-BSA the animals were subjected to RE and six hours after workout were euthanised. Results The rheumatoid arthritis provoked reduction in the cross-sectional area (CSA) of muscle fibres, but the CSA was lower in the RAOV when compared to the RA groups. Skeletal muscle atrogin-1 mRNA level was increased in arthritic rats (RA and RAOV), but the atrogin-1 level was higher in RAOV group when compared to other arthritic groups. The Muscle MuRF-1 mRNA level was also increased in the RAOV group. The increased atrogin-1 and MuRF-1 mRNA levels were lower in the RAOVEX group than in the RAOV group. The myostatin mRNA level was similar in all groups, except for the RAOVEX group, in which it was lower than the other groups. Conclusions LOF results in increased loss of skeletal muscle-related ubiquitin ligases (atrogin-1 and MuRF-1). However, the RE reduces the atrogin-1, MuRF-1, and myostatin mRNA levels in muscle of arthritic rats affected by LOF. PMID:28250722

  16. Anesthesia with propofol induces insulin resistance systemically in skeletal and cardiac muscles and liver of rats

    Energy Technology Data Exchange (ETDEWEB)

    Yasuda, Yoshikazu; Fukushima, Yuji; Kaneki, Masao [Department of Anaesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital, Shriners Hospitals for Children, Harvard Medical School, Boston, MA 02114 (United States); Martyn, J.A. Jeevendra, E-mail: jmartyn@partners.org [Department of Anaesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital, Shriners Hospitals for Children, Harvard Medical School, Boston, MA 02114 (United States)

    2013-02-01

    Highlights: ► Propofol, as a model anesthetic drug, induced whole body insulin resistance. ► Propofol anesthesia decreased glucose infusion rate to maintain euglycemia. ► Propofol decreased insulin-mediated glucose uptake in skeletal and cardiac muscles. ► Propofol increased hepatic glucose output confirming hepatic insulin resistance. -- Abstract: Hyperglycemia together with hepatic and muscle insulin resistance are common features in critically ill patients, and these changes are associated with enhanced inflammatory response, increased susceptibility to infection, muscle wasting, and worsened prognosis. Tight blood glucose control by intensive insulin treatment may reduce the morbidity and mortality in intensive care units. Although some anesthetics have been shown to cause insulin resistance, it remains unknown how and in which tissues insulin resistance is induced by anesthetics. Moreover, the effects of propofol, a clinically relevant intravenous anesthetic, also used in the intensive care unit for sedation, on insulin sensitivity have not yet been investigated. Euglycemic hyperinsulinemic clamp study was performed in rats anesthetized with propofol and conscious unrestrained rats. To evaluate glucose uptake in tissues and hepatic glucose output [{sup 3}H]glucose and 2-deoxy[{sup 14}C]glucose were infused during the clamp study. Anesthesia with propofol induced a marked whole-body insulin resistance compared with conscious rats, as reflected by significantly decreased glucose infusion rate to maintain euglycemia. Insulin-stimulated tissue glucose uptake was decreased in skeletal muscle and heart, and hepatic glucose output was increased in propofol anesthetized rats. Anesthesia with propofol induces systemic insulin resistance along with decreases in insulin-stimulated glucose uptake in skeletal and heart muscle and attenuation of the insulin-mediated suppression of hepatic glucose output in rats.

  17. [Energy reactions in the skeletal muscles of rats after a flight on the Kosmos-1129 biosatellite].

    Science.gov (United States)

    Mailian, E S; Buravkova, L B; Kokoreva, L V

    1983-01-01

    The polarographic analysis of biological oxidation in rat skeletal muscles after the 18.5-day flight revealed changes specific for the flight animals: oxidative phosphorylation uncoupling, distinct inertness of energy accumulation 10 hrs after recovery. Tissue respiration inhibition occurred in both flight and synchronous rats suggesting the effect of other than weightlessness factors. In the flight animals the parameters of energy metabolism returned to the prelaunch level within a longer (29 days) time than in the synchronous rats (6 days). Muscles of different function (predominance of fast or slow fibers) showed similar responses of energy metabolism to weightlessness, i. e. inhibition of the intensity and decrease of the energy efficiency of oxidative processes.

  18. Ipsilateral inspiratory intercostal muscle activity after C2 spinal cord hemisection in rats.

    Science.gov (United States)

    Beth Zimmer, M; Grant, Joshua S; Ayar, Angelo E; Goshgarian, Harry G

    2015-03-01

    Upper cervical spinal cord hemisection causes paralysis of the ipsilateral hemidiaphragm; however, the effect of C2 hemisection on the function of the intercostal muscles is not clear. We hypothesized that C2 hemisection would eliminate inspiratory intercostal activity ipsilateral to the injury and that some activity would return in a time-dependent manner. Female Sprague Dawley rats were anesthetized with urethane and inspiratory intercostal electromyogram (EMG) activity was recorded in control rats, acutely injured C2 hemisected rats, and at 1 and 16 weeks post C2 hemisection. Bilateral recordings of intercostal EMG activity showed that inspiratory activity was reduced immediately after injury and increased over time. EMG activity was observed first in rostral spaces followed by recovery occurring in caudal spaces. Theophylline increased respiratory drive and increased intercostal activity, inducing activity that was previously absent. These results suggest that there are crossed, initially latent, respiratory connections to neurons innervating the intercostal muscles similar to those innervating phrenic motor neurons.

  19. Na+-K+ pump location and translocation during muscle contraction  in rat skeletal muscle

    DEFF Research Database (Denmark)

    Kristensen, Michael; Rasmussen, Martin Krøyer; Juel, Carsten

    2008-01-01

    , in an outer-membrane-enriched fraction and a 41% and 17% increase, respectively, in sarcolemma giant vesicles. The Na+-K+ pump activity measured with the 3-O-MFPase assay was increased by 37% in giant vesicles from exercised rats. Immunoprecipitation with Cav-3 antibody showed that 17%, 11% and 14% of the a1......Muscle contraction may up-regulate the number of Na+-K+ pumps in the plasma membrane by translocation of subunits. Since there is still controversy about where this translocation takes place from and if it takes place at all, the present study used different techniques to characterize...

  20. Branched-chain amino acid-rich diet improves skeletal muscle wasting caused by cigarette smoke in rats.

    Science.gov (United States)

    Tomoda, Koichi; Kubo, Kaoru; Hino, Kazuo; Kondoh, Yasunori; Nishii, Yasue; Koyama, Noriko; Yamamoto, Yoshifumi; Yoshikawa, Masanori; Kimura, Hiroshi

    2014-04-01

    Cigarette smoke induces skeletal muscle wasting by a mechanism not yet fully elucidated. Branched-chain amino acids (BCAA) in the skeletal muscles are useful energy sources during exercise or systemic stresses. We investigated the relationship between skeletal muscle wasting caused by cigarette smoke and changes in BCAA levels in the plasma and skeletal muscles of rats. Furthermore, the effects of BCAA-rich diet on muscle wasting caused by cigarette smoke were also investigated. Wistar Kyoto (WKY) rats that were fed with a control or a BCAA-rich diet were exposed to cigarette smoke for four weeks. After the exposure, the skeletal muscle weight and BCAA levels in plasma and the skeletal muscles were measured. Cigarette smoke significantly decreased the skeletal muscle weight and BCAA levels in both plasma and skeletal muscles, while a BCAA-rich diet increased the skeletal muscle weight and BCAA levels in both plasma and skeletal muscles that had decreased by cigarette smoke exposure. In conclusion, skeletal muscle wasting caused by cigarette smoke was related to the decrease of BCAA levels in the skeletal muscles, while a BCAA-rich diet may improve cases of cigarette smoke-induced skeletal muscle wasting.

  1. [Relationship between PMI and fourier transform infrared spectral changes in muscle of rats after death caused by mechanical asphyxial].

    Science.gov (United States)

    Li, Shi-ying; Shao, Yu; Li, Zheng-dong; Liu, Ning-guo; Zou, Dong-hua; Qin, Zhi-qiang; Chen, Yi-jiu; Huang, Ping

    2012-06-01

    To observe the postmortem degradation process in rat myocardium and skeletal muscle using Fourier transform infrared (FTIR) spectroscopy and to provide a new method for estimating postmortem interval (PMI). Left ventricle and skeletal muscles of rats dying of mechanical asphyxiated were sampled at different PMIs. The changes of different chemical functional group in the myocardium and skeletal muscle samples were measured by FTIR spectroscopy. The different absorbance (A) ratios of peaks were calculated and the curve estimation analysis between absorbance ratios (x) and PMI (y) were performed to establish six mathematical models. FTIR spectral absorption peak of rat myocardium and skeletal muscle showed three changes: increase, decrease and stable. The cubic model function showed the strongest correlation coefficient. The A1080/A1396 ratio of skeletal muscle showed the strongest correlation coefficient (r = 0.832) with more accurate determination of PMI. FYIR spectroscopy can be potentially used as an effective method for estimating PMI in forensic practice using myocardium and skeletal muscle.

  2. Estimation of musculoskeletal models from in situ measurements of muscle action in the rat hindlimb.

    Science.gov (United States)

    Yeo, Sang Hoon; Mullens, Christopher H; Sandercock, Thomas G; Pai, Dinesh K; Tresch, Matthew C

    2011-03-01

    Musculoskeletal models are often created by making detailed anatomical measurements of muscle properties. These measurements can then be used to determine the parameters of canonical models of muscle action. We describe here a complementary approach for developing and validating muscle models, using in situ measurements of muscle actions. We characterized the actions of two rat hindlimb muscles: the gracilis posticus (GRp) and the posterior head of biceps femoris (BFp; excluding the anterior head with vertebral origin). The GRp is a relatively simple muscle, with a circumscribed origin and insertion. The BFp is more complex, with an insertion distributed along the tibia. We measured the six-dimensional isometric forces and moments at the ankle evoked from stimulating each muscle at a range of limb configurations. The variation of forces and moments across the workspace provides a succinct characterization of muscle action. We then used this data to create a simple muscle model with a single point insertion and origin. The model parameters were optimized to best explain the observed force-moment data. This model explained the relatively simple muscle, GRp, very well (R(2)>0.85). Surprisingly, this simple model was also able to explain the action of the BFp, despite its greater complexity (R(2)>0.84). We then compared the actions observed here with those predicted using recently published anatomical measurements. Although the forces and moments predicted for the GRp were very similar to those observed here, the predictions for the BFp differed. These results show the potential utility of the approach described here for the development and refinement of musculoskeletal models based on in situ measurements of muscle actions.

  3. Acute and chronic changes in rat soleus muscle after high-fat high-sucrose diet.

    Science.gov (United States)

    Collins, Kelsey H; Hart, David A; Smith, Ian C; Issler, Anthony M; Reimer, Raylene A; Seerattan, Ruth A; Rios, Jaqueline L; Herzog, Walter

    2017-05-01

    The effects of obesity on different musculoskeletal tissues are not well understood. The glycolytic quadriceps muscles are compromised with obesity, but due to its high oxidative capacity, the soleus muscle may be protected against obesity-induced muscle damage. To determine the time-course relationship between a high-fat/high-sucrose (HFS) metabolic challenge and soleus muscle integrity, defined as intramuscular fat invasion, fibrosis and molecular alterations over six time points. Male Sprague-Dawley rats were fed a HFS diet (n = 64) and killed at serial short-term (3 days, 1 week, 2 weeks, 4 weeks) and long-term (12 weeks, 28 weeks) time points. Chow-fed controls (n = 21) were killed at 4, 12, and 28 weeks. At sacrifice, animals were weighed, body composition was calculated (DXA), and soleus muscles were harvested and flash-frozen. Cytokine and adipokine mRNA levels for soleus muscles were assessed, using RT-qPCR Histological assessment of muscle fibrosis and intramuscular fat was conducted, CD68(+) cell number was determined using immunohistochemistry, and fiber typing was assessed using myosin heavy chain protein analysis. HFS animals demonstrated significant increases in body fat by 1 week, and this increase in body fat was sustained through 28 weeks on the HFS diet. Short-term time-point soleus muscles demonstrated up-regulated mRNA levels for inflammation, atrophy, and oxidative stress molecules. However, intramuscular fat, fibrosis, and CD68(+) cell number were similar to their respective control group at all time points evaluated. Therefore, the oxidative capacity of the soleus may be protective against diet-induced alterations to muscle integrity. Increasing oxidative capacity of muscles using aerobic exercise may be a beneficial strategy for mitigating obesity-induced muscle damage, and its consequences. © 2017 The Authors. Physiological Reports published by Wiley Periodicals, Inc. on behalf of The Physiological Society and the American

  4. Muscle differentiation after sciatic nerve transection and reinnervation in adult rats.

    Science.gov (United States)

    Ijkema-Paassen, J; Meek, M F; Gramsbergen, A

    2001-07-01

    Reinnervation after peripheral nerve transections generally leads to poor functional recovery. In order to study whether changes in muscles might be a contributing factor in this phenomenon we studied muscle morphology and fibre type distributions after sciatic nerve transection in the rat hind limb. Proximally, before the bifurcation in the tibial and common peroneal nerve, a 12 mm segment of the sciatic nerve was resected, reversed and re-implanted as an autologous nerve graft. After survival periods of 7, 15 and 21 weeks the lateral gastrocnemius, tibialis anterior and soleus muscles were dissected, stained with mATP-ase, and fibre type distributions were studied. In addition, numbers of muscle fibres were counted, and cross sectional areas were calculated. After 7 weeks, cross sectional areas were decreased in all muscles. In the gastrocnemius and tibialis anterior muscles the fibre number remained unaltered but the hypotrophy had been reversed at later ages. The number of muscle fibres in the soleus muscle remained decreased over the entire period of observation. The percentages of type II fibres in the gastrocnemius and tibialis anterior muscles were decreased at 7 and 15 weeks but these again approached normal values at 21 weeks. The type I fibres, however, remained arranged in groups. In the soleus muscle a large increase in the percentage of type II muscle fibres was observed and this remained until 21 weeks. We conclude that a non-selective reinnervation and later readjustments by regression of polyneural innervation may in part explain the changes in distributions of various fibre types.

  5. Proteinous amino acids in hearts' muscle cytosol of rats pretreated with digoxin, caffeine or isoproterenol.

    Science.gov (United States)

    Gabrys, Janusz; Konecki, Janusz; Głowacka, Maria; Durczok, Katarzyna; Nowak, Przemysław; Bielaczyc, Grzegorz; Brus, Ryszard; Shani, Jashovam

    2004-01-01

    Levels of the 19 proteinous amino acids and total free amino acids were assayed by gas-liquid chromatography in cytosols of rat atrial and ventricular muscle cardiomyocytes. The tissues were assayed after the rats had been exposed to the cardioactive drugs digoxin, caffeine, and isoproterenol, each having different mechanisms of action. We demonstrated that, in the atrial and ventricular cardiac muscle cytosol of control (untreated) rats, arginine, glutamine, and cysteine existed in their highest levels: 35.1% and 17.6%; 14.8% and 51.6%; 9.9% and 0.25% of the total free amino acids, respectively. The levels of the other amino acids in the atrial and ventricular cardiac muscle cytosols ranged between 0.1% and 10.0% of the total free amino acids. Digoxin, caffeine, and isoproterenol significantly reduced the total amount of cytosolic free amino acids in the atrial heart muscle cytosol to 7.6%, 9.0%, and 9.2% of the control value (100%), and in the ventricular heart muscle cytosol to 31.1%, 43.2%, and 28.3% of the control. The three drugs tested changed the cytosols' levels of arginine, cysteine, tryptophane, asparagine, and tyrosine in atrial and ventricular heart muscle cytosol, as compared to the control groups (calculated as a percent of the total free amino acids in the experimental groups). The role of proteinous amino acids in the function of the heart muscle and in the mechanism of action of these drugs on the mammalian heart is discussed.

  6. Acute effects of stretching exercise on the soleus muscle of female aged rats.

    Science.gov (United States)

    Zotz, Talita Gnoato; Capriglione, Luiz Guilherme A; Zotz, Rafael; Noronha, Lucia; Viola De Azevedo, Marina Louise; Fiuza Martins, Hilana Rickli; Silveira Gomes, Anna Raquel

    2016-01-01

    It has been shown that stretching exercises can improve the flexibility and independence of the elderly. However, although these exercises commonly constitute training programs, the morphological adaptations induced by stretching exercises in aged skeletal muscle are still unclear. To assess the acute effects of passive mechanical static stretching on the morphology, sarcomerogenesis and modulation of important components of the extracellular matrix of the soleus muscle of aged female rats. Fifteen old female rats with 26 months were divided into two groups: stretching (n=8, SG) and control (n=7, CG): The stretching protocol consisted of 4 repetitions each of 1 min with 30s interval between sets. Stretching was performed on the left soleus muscle, 3 times a week for 1 week. After three sessions, the rats were anesthetized to remove the left soleus muscle, and then euthanized. The following analyses were carried out: muscle fiber cross-sectional area and serial sarcomere number; immunohistochemistry for the quantification of collagen I, III and TGFβ-1. a decrease in muscle fiber cross-sectional area of the SG was observed when compared to the CG (p=0.0001, Kruskal-Wallis); the percentage of type I collagen was significantly lower in the SG when compared to the CG (p=0.01, Kruskal-Wallis), as well as the percentage of TGFβ-1 (p=0.04, Kruskal-Wallis); collagen III was significantly higher in the SG than in the CG (7.06±6.88% vs 4.92±5.30%, p=0.01, Kruskal-Wallis). Although the acute stretching induced muscle hypotrophy, an antifibrotic action was detected. Copyright © 2015 Elsevier GmbH. All rights reserved.

  7. Effects of Hyperbaric Oxygen on Metabolic Capacity of the Skeletal Muscle in Type 2 Diabetic Rats with Obesity

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    Naoto Fujita

    2012-01-01

    Full Text Available We investigated whether hyperbaric oxygen enhances the oxidative metabolic capacity of the skeletal muscle and attenuates adipocyte hypertrophy in type 2 diabetic rats with obesity. Five-week-old male Otsuka Long-Evans Tokushima fatty (OLETF and Long-Evans Tokushima Otsuka (LETO rats were used as diabetic animals and nondiabetic controls, respectively, and assigned to control and hyperbaric oxygen groups. Animals in the hyperbaric oxygen group were exposed to an atmospheric pressure of 1.25 with an oxygen concentration of 36% for 3 h daily. The glucose level at 27 weeks of age was significantly higher in OLETF rats than in LETO rats, but the elevation was inhibited in OLETF rats exposed to hyperbaric oxygen. The slow-to-fast fiber transition in the skeletal muscle was observed in OLETF rats, but the shift was inhibited in OLETF rats exposed to hyperbaric oxygen. Additionally, the oxidative enzyme activity of muscle fibers was increased by hyperbaric oxygen. The adipocyte size was larger in OLETF rats than in LETO rats, but hypertrophied adipocytes were not observed in OLETF rats exposed to hyperbaric oxygen. Hyperbaric oxygen enhances glucose and lipid metabolism in the skeletal muscle, indicating that hyperbaric oxygen can prevent elevation of glucose and adipocyte hypertrophy in diabetic rats with obesity.

  8. [Modulation of the effects of dexamethasone in rat skeletal muscle by testosterone].

    Science.gov (United States)

    Trush, V V; Soboliev, V I

    2013-01-01

    In experiments on young females white rats by means of methods of electromyography and ergography we investigated the efficiency of a testosterone-propionate for smoothing of negative effects of dexamethasone on skeletal muscle. It has been established that the chronic injection of dexamethasone causes the decreasing of amplitude of contraction of forward tibial muscle on 29.7-59.3% (after 5-25 injections) and the lengthening of the latent period of muscle's excitation on 18.5-16.5% (after 15-25 injections), whereas the complex application of testosterone and dexamethasone prevents the changing of these parameters. At the same time testosterone didn't provide the smoothing of negative influence of dexamethasone on muscle's resistance to fatigue development.

  9. Microtransplantation of acetylcholine receptors from normal or denervated rat skeletal muscles to frog oocytes

    Science.gov (United States)

    Bernareggi, Annalisa; Reyes-Ruiz, Jorge Mauricio; Lorenzon, Paola; Ruzzier, Fabio; Miledi, Ricardo

    2011-01-01

    Cell membranes, carrying neurotransmitter receptors and ion channels, can be ‘microtransplanted’ into frog oocytes. This technique allows a direct functional characterization of the original membrane proteins, together with any associated molecules they may have, still embedded in their natural lipid environment. This approach has been previously demonstrated to be very useful to study neurotransmitter receptors and ion channels contained in cell membranes isolated from human brains. Here, we examined the possibility of using the microtransplantation method to study acetylcholine receptors from normal and denervated rat skeletal muscles. We found that the muscle membranes, carrying their fetal or adult acetylcholine receptor isoforms, could be efficiently microtransplanted to the oocyte membrane, making the oocytes become sensitive to acetylcholine. These results show that oocytes injected with skeletal muscle membranes efficiently incorporate functional acetylcholine receptors, thus making the microtransplantation approach a valuable tool to further investigate receptors and ion channels of human muscle diseases. PMID:21224230

  10. Decreased insulin action on muscle glucose transport after eccentric contractions in rats

    DEFF Research Database (Denmark)

    Asp, S; Richter, Erik

    1996-01-01

    We have recently shown that eccentric contractions (Ecc) of rat calf muscles cause muscle damage and decreased glycogen and glucose transporter GLUT-4 protein content in the white (WG) and red gastrocnemius (RG) but not in the soleus (S) (S. Asp, S. Kristiansen, and E. A. Richter. J. Appl. Physiol....... 79: 1338-1345, 1995). To study whether these changes affect insulin action, hindlimbs were perfused at three different insulin concentrations (0, 200, and 20,000 microU/ml) 2 days after one-legged eccentric contractions of the calf muscles. Compared with control, basal glucose transport was slightly...... velocity of glycogen synthase increased similarly with increasing insulin concentrations in Ecc- and control WG and RG. We conclude that insulin action on glucose transport but not glycogen synthase activity is impaired in perfused muscle exposed to prior eccentric contractions....

  11. Skeletal Muscle Satellite Cell Activation Following Cutaneous Burn in Rats

    Science.gov (United States)

    2013-12-01

    Satellite cell isolation and culture Satellite cells were isolated similar as described by Allen et al. [30]. Following euthanasia , muscles were...satellite cell cultures. Methods Cell Biol 1997;52:155–76. [31] Tatsumi R, Liu X, Pulido A, Morales M, Sakata T, Dial S, Hattori A, Ikeuchi Y, Allen RE

  12. Smooth muscle pharmacology in the isolated virgin and pregnant rat uterus and cervix.

    Science.gov (United States)

    Darios, Emma S; Seitz, Bridget; Watts, Stephanie W

    2012-06-01

    Uterine smooth muscle function is established, but comparatively little is known about cervical smooth muscle pharmacology. We performed a proof-of-principle experiment that smooth muscle was expressed in the cervix in both virgin and pregnant rats, using the uterus as a comparator. We tested whether all tissues were pharmacologically responsive to contractile and relaxant agonists. Immunohistochemistry revealed the expression of smooth muscle α-actin in all tissues. The isolated tissue bath was used to measure isometric contractility of uterine strips and whole cervices from virgin and pregnant (day 11 ± 2) female Sprague-Dawley rats. We tested classic activators of uterine smooth muscle contraction and relaxation in both uterus and cervix. All tissues contracted to the depolarizing agent potassium chloride, prostaglandin F2α, muscarinic cholinergic agonist carbachol [2-[(aminocarbonxyl)oxy]-N,N,N-trimethylethanaminium chloride], and 5-hydroxytryptamine. Unlike other tissues, the pregnant cervix did not contract to oxytocin, but the oxytocin receptor was present. Both cervix and uterus (virgin and pregnant) had concentration-dependent, near-complete relaxation to the adrenergic agonist norepinephrine and adenylate cyclase activator forskolin [(3R,4aR,5S,6S,6aS,10S,10aR,10bS)-6,10-10b-trihydroxy-3,4a,7,10a-pentamethyl-1-oxo-3-vinyldodecahydro-1H-benzo[f] chroment-5-yl acetate]. The β-adrenergic receptor agonist isoproterenol was less potent in pregnant cervix versus virgin by ∼10-fold. All tissues, particularly the cervix, responded poorly to the nitric-oxide donor sodium nitroprusside, relaxing ∼20% maximally. These findings support the importance of smooth muscle in the cervix, the use of the isolated cervix in pharmacological studies, and a similarity between smooth muscle pharmacology of the nonpregnant uterus and cervix. This work highlights the unappreciated smooth muscle function of the cervix versus uterus and cervical changes in pharmacology during

  13. Combined isometric, concentric, and eccentric resistance exercise prevents unloading-induced muscle atrophy in rats.

    Science.gov (United States)

    Adams, G R; Haddad, F; Bodell, P W; Tran, P D; Baldwin, K M

    2007-11-01

    Previously, we reported that an isometric resistance training program that was effective in stimulating muscle hypertrophy in ambulatory rats could not completely prevent muscle atrophy during unloading (Haddad F, Adams GR, Bodell PW, Baldwin KM. J Appl Physiol 100: 433-441, 2006). These results indicated that preventing muscle atrophy does not appear to be simply a function of providing an anabolic stimulus. The present study was undertaken to determine if resistance training, with increased volume (3-s contractions) and incorporating both static and dynamic components, would be effective in preventing unloading-induced muscle atrophy. Rats were exposed to 5 days of muscle unloading via tail suspension. During that time one leg received electrically stimulated resistance exercise (RE) that included an isometric, concentric, and eccentric phase. The results of this study indicate that this combined-mode RE provided an anabolic stimulus sufficient to maintain the mass and myofibril content of the trained but not the contralateral medial gastrocnemius (MG) muscle. Relative to the contralateral MG, the RE stimulus increased the amount of total RNA (indicative of translational capacity) as well as the mRNA for several anabolic/myogenic markers such as insulin-like growth factor-I, myogenin, myoferlin, and procollagen III-alpha-1 and decreased that of myostatin, a negative regulator of muscle size. The combined-mode RE protocol also increased the activity of anabolic signaling intermediates such as p70S6 kinase. These results indicate that a combination of static- and dynamic-mode RE of sufficient volume provides an effective stimulus to stimulate anabolic/myogenic mechanisms to counter the initial stages of unloading-induced muscle atrophy.

  14. Effects of eccentric exercise in rehabilitation of phasic and tonic muscles after leg immobilization in rats.

    Science.gov (United States)

    Cornachione, Anabelle S; Cação-Benedini, Letícia O; Chesca, Deise Lucia; Martinez, Edson Z; Mattiello-Sverzut, Ana Claudia

    2014-10-01

    Eccentric exercise is an essential resource for skeletal muscle rehabilitation following muscle disuse however, abnormalities linked to the tissue recuperation require further research. Our aim was analyze the adaptation ability of rehabilitated muscular tissue in rats during different periods of eccentric training after 10 days of limb immobilization. Twenty-seven Wistar rats were divided into six groups: immobilized 10 days, immobilized and eccentric trained for 10 days, immobilized and eccentric trained for 21 days, and three age-matched control groups. After sacrifice, soleus and plantaris muscles were frozen, cut and stained for general histology using hematoxylin and eosin and Gomori trichrome methods and immunohistochemical methods for fiber typing (mATPase, NADH2-TR), for capillaries (CD31) and intermediate filaments (desmin, vimentin) and high resolution microscopy of resin embedded material. Immobilization resulted in more intense morphological alterations in soleus muscles such as formation of target fibers, nuclear centralization, a reduction in the number of type I fibers, diameter of type I, IIA, IIAD fibers, and capillaries. After 10 days of eccentric training, increases in the nuclear centralization and the number of lobulated fibers were observed. This period was insufficient to reestablish the capillary/fiber (C/F) ratio and distribution of fiber types as that observed in the control group. However, 21 days of rehabilitation allowed the reversal of all morphological and quantitative abnormalities. For the plantaris muscles, 10-days of training restored their basic characteristics. Despite the fact that immobilization affected soleus and plantaris muscles, 10 days of eccentric training was insufficient to restore the morphological characteristics of soleus muscles, which was not the case observed in plantaris muscle.

  15. Anatomy and Disorders of the Oral Cavity of Rat-like and Squirrel-like Rodents.

    Science.gov (United States)

    Mancinelli, Elisabetta; Capello, Vittorio

    2016-09-01

    The order Rodentia comprises more than 2000 species divided into 3 groups based on anatomic and functional differences of the masseter muscle. Myomorph and sciuromorph species have elodont incisors and anelodont cheek teeth, unlike hystrichomorph species which have full anelodont dentition. Diseases of incisors and cheek teeth of rat-like and squirrel-like rodents result in a wide variety of symptoms and clinical signs. Appropriate diagnostic testing and imaging techniques are required to obtain a definitive diagnosis, formulate a prognosis, and develop a treatment plan. A thorough review of elodontoma, odontoma, and pseudo-odontoma is provided, including treatment of pseudo-odontomas in prairie dogs.

  16. Impairment of Electron Transfer Chain Induced by Acute Carnosine Administration in Skeletal Muscle of Young Rats

    Directory of Open Access Journals (Sweden)

    José Roberto Macarini

    2014-01-01

    Full Text Available Serum carnosinase deficiency is an inherited disorder that leads to an accumulation of carnosine in the brain tissue, cerebrospinal fluid, skeletal muscle, and other tissues of affected patients. Considering that high levels of carnosine are associated with neurological dysfunction and that the pathophysiological mechanisms involved in serum carnosinase deficiency remain poorly understood, we investigated the in vivo effects of carnosine on bioenergetics parameters, namely, respiratory chain complexes (I–III, II, and II-III, malate dehydrogenase, succinate dehydrogenase, and creatine kinase activities and the expression of mitochondrial-specific transcription factors (NRF-1, PGC-1α, and TFAM in skeletal muscle of young Wistar rats. We observed a significant decrease of complexes I–III and II activities in animals receiving carnosine acutely, as compared to control group. However, no significant alterations in respiratory chain complexes, citric acid cycle enzymes, and creatine kinase activities were found between rats receiving carnosine chronically and control group animals. As compared to control group, mRNA levels of NRF-1, PGC-1α, and TFAM were unchanged. The present findings indicate that electron transfer through the respiratory chain is impaired in skeletal muscle of rats receiving carnosine acutely. In case these findings are confirmed by further studies and ATP depletion is also observed, impairment of bioenergetics could be considered a putative mechanism responsible for the muscle damage observed in serum carnosinase-deficient patients.

  17. Ginseng administration protects skeletal muscle from oxidative stress induced by acute exercise in rats.

    Science.gov (United States)

    Voces, J; Cabral de Oliveira, A C; Prieto, J G; Vila, L; Perez, A C; Duarte, I D G; Alvarez, A I

    2004-12-01

    Enzymatic activity was analyzed in the soleus, gastrocnemius (red and white) and plantaris muscles of acutely exercised rats after long-term administration of Panax ginseng extract in order to evaluate the protective role of ginseng against skeletal muscle oxidation. Ginseng extract (3, 10, 100, or 500 mg/kg) was administered orally for three months to male Wistar rats weighing 200 +/- 50 g before exercise and to non-exercised rats (N = 8/group). The results showed a membrane stabilizing capacity of the extract since mitochondrial function measured on the basis of citrate synthase and 3-hydroxyacyl-CoA dehydrogenase activities was reduced, on average, by 20% (P < 0.05) after exercise but the activities remained unchanged in animals treated with a ginseng dose of 100 mg/kg. Glutathione status did not show significant changes after exercise or treatment. Lipid peroxidation, measured on the basis of malondialdehyde levels, was significantly higher in all muscles after exercise, and again was reduced by about 74% (P < 0.05) by the use of ginseng extract. The administration of ginseng extract was able to protect muscle from exercise-induced oxidative stress irrespective of fiber type.

  18. Ginseng administration protects skeletal muscle from oxidative stress induced by acute exercise in rats

    Directory of Open Access Journals (Sweden)

    J. Voces

    2004-12-01

    Full Text Available Enzymatic activity was analyzed in the soleus, gastrocnemius (red and white and plantaris muscles of acutely exercised rats after long-term administration of Panax ginseng extract in order to evaluate the protective role of ginseng against skeletal muscle oxidation. Ginseng extract (3, 10, 100, or 500 mg/kg was administered orally for three months to male Wistar rats weighing 200 ± 50 g before exercise and to non-exercised rats (N = 8/group. The results showed a membrane stabilizing capacity of the extract since mitochondrial function measured on the basis of citrate synthase and 3-hydroxyacyl-CoA dehydrogenase activities was reduced, on average, by 20% (P < 0.05 after exercise but the activities remained unchanged in animals treated with a ginseng dose of 100 mg/kg. Glutathione status did not show significant changes after exercise or treatment. Lipid peroxidation, measured on the basis of malondialdehyde levels, was significantly higher in all muscles after exercise, and again was reduced by about 74% (P < 0.05 by the use of ginseng extract. The administration of ginseng extract was able to protect muscle from exercise-induced oxidative stress irrespective of fiber type.

  19. Double muscle innervation using end-to-side neurorrhaphy in rats

    Directory of Open Access Journals (Sweden)

    Elisangela Jeronymo Stipp-Brambilla

    Full Text Available CONTEXT AND OBJECTIVE: One of the techniques used for treating facial paralysis is double muscle innervation using end-to-end neurorrhaphy with sectioning of healthy nerves. The aim of this study was to evaluate whether double muscle innervation by means of end-to-side neurorrhaphy could occur, with maintenance of muscle innervation. DESIGN AND SETTING: Experimental study developed at the Experimental Research Center, Faculdade de Medicina de Botucatu, Unesp. METHODS: One hundred rats were allocated to five groups as follows: G1, control group; G2, the peroneal nerve was sectioned; G3, the tibial nerve was transected and the proximal stump was end-to-side sutured to the intact peroneal nerve; G4, 120 days after the G3 surgery, the peroneal nerve was sectioned proximally to the neurorrhaphy; G5, 120 days after the G3 surgery, the peroneal and tibial nerves were sectioned proximally to the neurorrhaphy. RESULTS: One hundred and fifty days after the surgery, G3 did not show any change in tibial muscle weight or muscle fiber diameter, but the axonal fiber diameter in the peroneal nerve distal to the neurorrhaphy had decreased. Although G4 showed atrophy of the cranial tibial muscle 30 days after sectioning the peroneal nerve, the electrophysiological test results and axonal diameter measurement confirmed that muscle reinnervation had occurred. CONCLUSION: These findings suggest that double muscle innervation did not occur through end-to-side neurorrhaphy; the tibial nerve was not able to maintain muscle innervation after the peroneal nerve had been sectioned, although muscle reinnervation was found to have occurred, 30 days after the peroneal nerve had been sectioned.

  20. Muscle atrophy associated with microgravity in rat: Basic data for countermeasures

    Science.gov (United States)

    Falempin, M.; Mounier, Y.

    Morphological, contractile properties and myosin heavy chain (MHC) composition of rat soleus muscles were studied after 2 weeks of unloading (HS) and after 2 weeks of HS associated with selective deafferentation (HS + DEAF) at the level L4 and L5. The same significant reductions in muscle mass and tetanic tension were found after HS and HS + DEAF. However, the transformation of the slow-twitch soleus muscle towards a faster type characterized by a decrease in twitch time parameters and an increase in fast-twitch type MHC isoforms in HS did not appear in HS + DEAF conditions. Our results also showed that a pattern similar to firing rate of motoneurones innervating slow-twitch muscles inhibited the slow to fast fiber changes observed during HS. Nevertheless, neither the loss of mass or force output in the HS muscles were prevented by electrostimulation. Immobilization in a stretched position during HS maintained the muscle wet weight, mechanical and electrophoretical characteristics close to control values. We concluded that the decrease in mechanical strains imposed on the muscle during unloading was the main factor for the development of atrophy, while the kinetic changes might be predominantly modulated by the nervous command. These basic data suggested that some experimental conditions such as electrostimulation or stretching, could participate in countermeasure programmes.

  1. Hsp25 and Hsp72 content in rat skeletal muscle following controlled shortening and lengthening contractions.

    Science.gov (United States)

    Holwerda, Andrew M; Locke, Marius

    2014-12-01

    The cytoprotective proteins, Hsp25 and Hsp72, are increased in skeletal muscle after nondamaging, shortening contractions, but the temporal pattern of expression and stimulatory mechanisms remain unclear. Thus, we sought to define the in vivo temporal patterns of expression for Hsp25 and Hsp72 after 2 opposing contractions types. To do this, male Sprague-Dawley rats had 1 tibialis anterior (TA) muscle electrically stimulated (5 sets of 20 repetitions) while being either forcibly lengthened (LC) or shortened (SC). At 2, 8, 24, 48, 72, or 168 h after the contractions both the stimulated and the nonstimulated (contra-lateral control) TA muscles were removed and processed to examine muscle damage (hemotoxylin and eosin staining) and Hsp content (Western blot analyses). Cross-sections from TA muscles subjected to LCs showed muscle fibre damage at 8 h and thereafter. In contrast, no muscle fibre damage was observed at any time point following SCs. When normalized to contra-lateral controls, Hsp25 and Hsp72 content were significantly (P < 0.01) increased at 24 h (3.1- and 3.8-fold, respectively) and thereafter. There were no significant increases in Hsp25 or Hsp72 content at any time point following SC. These data suggest that LCs, but not SCs, result in Hsp accumulation and that the fibre/cellular damage sustained from LCs may be the stimulus for elevating Hsp content.

  2. l-Carnitine supplement reduces skeletal muscle atrophy induced by prolonged hindlimb suspension in rats.

    Science.gov (United States)

    Jang, Jiwoong; Park, Jonghoon; Chang, Hyukki; Lim, Kiwon

    2016-12-01

    l-Carnitine was recently found to downregulate the ubiquitin proteasome pathway (UPP) and increase insulin-like growth factor 1 concentrations in animal models. However, the effect of l-carnitine administration on disuse muscle atrophy induced by hindlimb suspension has not yet been studied. Thus, we hypothesized that l-carnitine may have a protective effect on muscle atrophy induced by hindlimb suspension via the Akt1/mTOR and/or UPP. Male Wistar rats were assigned to 3 groups: hindlimb suspension group, hindlimb suspension with l-carnitine administration (1250 mg·kg(-1)·day(-1)) group, and pair-fed group adjusted hindlimb suspension. l-Carnitine administration for 2 weeks of hindlimb suspension alleviated the decrease in weight and fiber size in the soleus muscle. In addition, l-carnitine suppressed atrogin-1 mRNA expression, which has been reported to play a pivotal role in muscle atrophy. The present study shows that l-carnitine has a protective effect against soleus muscle atrophy caused by hindlimb suspension and decreased E3 ligase messenger RNA expression, suggesting the possibility that l-carnitine protects against muscle atrophy, at least in part, through the inhibition of the UPP. These observations suggest that l-carnitine could serve as an effective supplement in the decrease of muscle atrophy caused by weightlessness in the fields of clinical and rehabilitative research.

  3. Desensitized morphological and cytokine response after stretch-shortening muscle contractions as a feature of aging in rats.

    Science.gov (United States)

    Rader, Erik P; Layner, Kayla N; Triscuit, Alyssa M; Kashon, Michael L; Gu, Ja K; Ensey, James; Baker, Brent A

    2015-12-01

    Recovery from contraction-induced injury is impaired with aging. At a young age, the secondary response several days following contraction-induced injury consists of edema, inflammatory cell infiltration, and segmental muscle fiber degeneration to aid in the clearance of damaged tissue and repair. This morphological response has not been wholly established at advanced age. Our aim was to characterize muscle fiber morphology 3 and 10 days following stretch-shortening contractions (SSCs) varying in repetition number (i.e. 0, 30, 80, and 150) for young and old rats. For muscles of young rats, muscle fiber degeneration was overt at 3 days exclusively after 80 or 150 SSCs and returned significantly closer to control values by 10 days. For muscles of old rats, no such responses were observed. Transcriptional microarray analysis at 3 days demonstrated that muscles of young rats differentially expressed up to 2144 genes while muscles of old rats differentially expressed 47 genes. Bioinformatic analysis indicated that cellular movement was a major biological process over-represented with genes that were significantly altered by SSCs especially for young rats. Protein levels in muscle for various cytokines and chemokines, key inflammatory factors for cell movement, increased 3- to 50-fold following high-repetition SSCs for young rats with no change for old rats. This age-related differential response was insightful given that for control (i.e. 0 SSCs) conditions, protein levels of circulatory cytokines/chemokines were increased with age. The results demonstrate ongoing systemic low-grade inflammatory signaling and subsequent desensitization of the cytokine/chemokine and morphological response to contraction-induced injury with aging - features which accompany age-related impairment in muscle recovery.

  4. Efficacy of maslinic acid and fenbendazole on muscle larvae of Trichinella zimbabwensis in laboratory rats.

    Science.gov (United States)

    Mukaratirwa, S; Gcanga, L; Kamau, J

    2016-01-01

    Trichinellosis is a zoonotic disease caused by nematode species of the genus Trichinella. Anthelmintics targeting the intestinal adults and muscle-dwelling larvae of Trichinella spp. have been tested, with limited success. This study was aimed at determining the efficacy of maslinic acid and fenbendazole on muscle larvae of Trichinella zimbabwensis in laboratory rats. Forty-two Sprague-Dawley rats, with an average weight of 270 g and 180 g for males and females respectively, were infected with T. zimbabwensis larvae. Infected rats were randomly assigned to three groups which were subjected to single treatments with each of maslinic acid, fenbendazole and a combination of both on day 25 post-infection (pi), and three groups which were subjected to double treatments with each of these drugs and a combination on days 25 and 32 pi. The untreated control group received a placebo. In single-treatment groups, the efficacy of each treatment, measured by rate of reduction in muscle larvae, was significant (P0.05). We conclude that the efficacy of maslinic acid against larval stages of T. zimbabwensis in rats was comparable to that of fenbendazole, with no side-effects observed, making maslinic acid a promising anthelmintic against larval stages of Trichinella species.

  5. Neuromuscular electrical stimulation improves GLUT-4 and morphological characteristics of skeletal muscle in rats with heart failure.

    Science.gov (United States)

    de Leon, E B; Bortoluzzi, A; Rucatti, A; Nunes, R B; Saur, L; Rodrigues, M; Oliveira, U; Alves-Wagner, A B; Xavier, L L; Machado, U F; Schaan, B D; Dall'Ago, P

    2011-02-01

    Changes in skeletal muscle morphology and metabolism are associated with limited functional capacity in heart failure, which can be attenuated by neuromuscular electrical stimulation (ES). The purpose of the present study was to analyse the effects of ES upon GLUT-4 protein content, fibre structure and vessel density of the skeletal muscle in a rat model of HF subsequent to myocardial infarction. Forty-four male Wistar rats were assigned to one of four groups: sham (S), sham submitted to ES (S+ES), heart failure (HF) and heart failure submitted to ES (HF+ES). The rats in the ES groups were submitted to ES of the left leg during 20 days (2.5 kHz, once a day, 30 min, duty cycle 50%- 15 s contraction/15 s rest). After this period, the left tibialis anterior muscle was collected from all the rats for analysis. HF+ES rats showed lower values of lung congestion when compared with HF rats (P = 0.0001). Although muscle weight was lower in HF rats than in the S group, thus indicating hypotrophy, 20 days of ES led to their recovery (P muscle vessel density (P muscle. © 2010 The Authors. Acta Physiologica © 2010 Scandinavian Physiological Society.

  6. Effect of chronic ethanol ingestion and exercise training on skeletal muscle in rat.

    Science.gov (United States)

    Vila, L; Ferrando, A; Voces, J; Cabral de Oliveira, C; Prieto, J G; Alvarez, A I

    2001-09-01

    The aim of this study was to investigate the interactive effects of exercise training and chronic ethanol consumption on metabolism, capillarity, and myofibrillar composition in rat limb muscles. Male Wistar rats were treated in separate groups as follows: non exercised-control; ethanol (15%) in animals' drinking water for 12 weeks; exercise training in treadmill and ethanol administration plus exercise for 12 weeks. Ethanol administration decreased capillarity and increased piruvate kinase and lactate dehydrogenase activities in white gastrocnemius; in plantaris muscle, ethanol increased citrate synthase activity and decreased cross-sectional area of type I, IIa, and IIb fibres. Exercise increased capillarity in all four limb muscles and decreased type I fibre area in plantaris. The decreased capillarity effect induced by ethanol in some muscles, was ameliorated when alcohol was combined with exercise. While alcoholic myopathy affects predominantly type IIb fibres, ethanol administration and aerobic exercise in some cases can affect type I and type IIa fibre areas. The exercise can decrease some harmful effects produced by ethanol in the muscle, including the decrease in the fibre area and capillary density.

  7. Effect of oxidative stress on Rho kinase II and smooth muscle contraction in rat stomach.

    Science.gov (United States)

    Al-Shboul, Othman; Mustafa, Ayman

    2015-06-01

    Recent studies have shown that both Rho kinase signaling and oxidative stress are involved in the pathogenesis of a number of human diseases, such as diabetes mellitus, hypertension, and atherosclerosis. However, very little is known about the effect of oxidative stress on the gastrointestinal (GI) smooth muscle Rho kinase pathway. The aim of the current study was to investigate the effect of oxidative stress on Rho kinase II and muscle contraction in rat stomach. The peroxynitrite donor 3-morpholinosydnonimine (SIN-1), hydrogen peroxide (H2O2), and peroxynitrite were used to induce oxidative stress. Rho kinase II expression and ACh-induced activity were measured in control and oxidant-treated cells via specifically designed enzyme-linked immunosorbent assay (ELISA) and activity assay kits, respectively. Single smooth muscle cell contraction was measured via scanning micrometry in the presence or absence of the Rho kinase blocker, Y-27632 dihydrochloride. All oxidant agents significantly increased ACh-induced Rho kinase II activity without affecting its expression level. Most important, oxidative stress induced by all three agents augmented ACh-stimulated muscle cell contraction, which was significantly inhibited by Y-27632. In conclusion, oxidative stress activates Rho kinase II and enhances contraction in rat gastric muscle, suggesting an important role in GI motility disorders associated with oxidative stress.

  8. Prior swimming exercise favors muscle recovery in adult female rats after joint immobilization.

    Science.gov (United States)

    Petrini, Ana Claudia; Ramos, Douglas Massoni; Gomes de Oliveira, Luana; Alberto da Silva, Carlos; Pertille, Adriana

    2016-07-01

    [Purpose] To evaluate the efficacy of pre-exercise on immobilization and subsequent recovery of white gastrocnemius (WG) and soleus (SOL) muscles of female rats. [Subjects and Methods] Thirty, 8-month-old, female Wistar rats were randomly and evenly allocated to six groups: sedentary (S); immobilized sedentary (IS); immobilized/rehabilitated sedentary (IRS); trained (T); immobilized trained (IT); and immobilized/rehabilitated trained (IRT). For four months, T, IT and IRT group animals performed swimming exercise (three sessions per week, 60 minutes per session), while S, IS and IRS groups animals remained housed in cages. After this period, the left hindlimb of the animals from the IS, IRS, IT and IRT groups was immobilized for five days, with the ankle at 90°. After removal of the orthosis, animals from the IRS and IRT groups followed a rehabilitation program based on swimming (five sessions per week, 60 minutes per session) for two weeks. [Results] Immobilization significantly reduced the cross-sectional area of the white gastrocnemius muscle; no changes were observed in the soleus muscles of the trained animals. Transforming growth factor-β1 protein levels were similar among the trained groups. [Conclusion] Prior swimming prevents hypotrophy of the soleus muscle after immobilization, and protein levels reflected the adaptive capacity of the skeletal muscle.

  9. Effects of space flight on GLUT-4 content in rat plantaris muscle

    Science.gov (United States)

    Tabata, I.; Kawanaka, Kentaro; Sekiguchi, Chiharu; Nagaoka, Shunji; Ohira, Yoshinobu

    The effects of 14 days of space flight on the glucose transporter protein (GLUT-4) were studied in the plantaris muscle of growing 9-week-old, male Sprague Dawley rats. The rats were randomly separated into five groups: pre-flight vivarium ground controls (PF-VC) sacrificed approximately 2 h after launch; flight groups sacrificed either approximately 5 h (F-R0) or 9 days (F-R9) after the return from space; and synchronous ground controls (SC-R0 and SC-R9) sacrificed at the same time as the respective flight groups. The flight groups F-R0 and F-R9 were exposed to micro-gravity for 14 days in the Spacelab module located in the cargo bay of the shuttle transport system - 58 of the manned Space Shuttle for the NASA mission named ''Spacelab Life Sciences 2''. Body weight and plantaris weight of SC-R0 and F-R0 were significantly higher than those of PF-VC. Neither body weight nor plantaris muscle weight in either group had changed 9 days after the return from space. As a result, body weight and plantaris muscle weight did not differ between the flight and synchronous control groups at any of the time points investigated. The GLUT-4 content (cpm/µg membrane protein) in the plantaris muscle did not show any significant change in response to 14 days of space flight or 9 days after return. Similarly, citrate synthase activity did not change during the course of the space flight or the recovery period. These results suggest that 14 days of space flight does not affect muscle mass or GLUT-4 content of the fast-twitch plantaris muscle in the rat.

  10. Electromyographic studies regarding denervation potentials in skeletal muscles at sites near and distant from the burn in rats.

    Science.gov (United States)

    Sajadi, Simin; Mansoori, Korosh; Forogh, Bijan; Fatemi, Mohammad Javad; Ahadi, Tannaz; Chahardoli Razji, Mahnaz

    2016-04-01

    Changes in membrane AChRs in skeletal muscles located near or distant from burn injury similar to denervated muscles may make electrodiagnostic features indistinguishable from true neuropathic changes. The aim of this study was to examine electrodiagnostic changes of muscles at sites local and distant from the burn after thermal injuries due to neuromuscular junction dysfunction. A total of 40 adult male rats were randomly allocated to four groups. Rats in group 1 received thermal burn injury over gastrocnemius muscle of one leg and sham burn on the other leg. A 20-25% and 30-35% surface body area burn and also 30-35% surface body area sham burn were produced at distant site from gastrocnemius muscle in group 2, 3 and 4, respectively. To explore any fibrillation potential, the rats underwent serial electromyographic studies of bilateral gastrocnemius muscles over 5 weeks after burn injury. There were no denervation potentials either in muscles at sites distant from 20-25% and 30-35% of total body surface area burns or in muscles beneath the burn. In the present study on rats, thermal burn injury could not make fibrillation potentials in the electrodiagnostic study of muscles located near and distant from the burn site.

  11. Early remodeling of rat cardiac muscle induced by swimming training