Role of Ca+2 and other second messengers in excitatory amino acid receptor mediated neurodegeneration: clinical perspectives

DEFF Research Database (Denmark)

Schousboe, A; Belhage, B; Frandsen, A

1997-01-01

Neurodegeneration associated with neurological disorders such as epilepsy, Huntington's Chorea, Alzheimer's disease, and olivoponto cerebellar atrophy or with energy failure such as ischemia, hypoxia, and hypoglycemia proceeds subsequent to overexposure of neurons to excitatory amino acids of which...... glutamate and aspartate may be quantitatively the most important. The toxic action of glutamate and aspartate is mediated through activation of glutamate receptors of the N-methyl-D-aspartate (NMDA) and non-NMDA subtypes. Antagonists for these receptors can act as neuroprotectants both in in vitro model...

Repeated injections of piracetam improve spatial learning and increase the stimulation of inositol phospholipid hydrolysis by excitatory amino acids in aged rats

NARCIS (Netherlands)

Canonico, P. L.; Aronica, E.; Aleppo, G.; Casabona, G.; Copani, A.; Favit, A.; Nicoletti, F.; Scapagnini, U.

1991-01-01

Repeated injections of piracetam (400 mg/kg, i.p. once a day for 15 days) to 16-month old rats led to an improved performance on an 8-arm radial maze, used as a test for spatial learning. This effect was accompanied by a greater ability of excitatory amino acids (ibotenate and glutamate) to

Up-Regulation of Excitatory Amino Acid Transporters EAAT1 and EAAT2 by ß-Klotho

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Jamshed Warsi

2015-12-01

Full Text Available Background/Aims: Klotho, a transmembrane protein expressed in chorioid plexus of the brain, kidney, and several other tissues, is required for inhibition of 1,25(OH2D3 formation by FGF23. The extracellular domain of Klotho protein could be cleaved off, thus being released into blood or cerebrospinal fluid. At least in part by exerting β-glucuronidase activity, soluble klotho regulates several ion channels and carriers. Klotho protein deficiency accelerates the appearance of age related disorders including neurodegeneration and muscle wasting and eventually leads to premature death. The present study explored the effect of Klotho protein on the excitatory glutamate transporters EAAT1 (SLC1A3 and EAAT2 (SLC1A2, Na+ coupled carriers clearing excitatory amino acids from the synaptic cleft and thus participating in the regulation of neuronal excitability. Methods: cRNA encoding EAAT1 or EAAT2 was injected into Xenopus laevis oocytes and glutamate (2 mM-induced inward current (IGlu taken as measure of glutamate transport. Measurements were made without or with prior 24 h treatment with soluble ß-Klotho protein (30 ng/ml in the absence and presence of β-glucuronidase inhibitor D-saccharic acid 1,4-lactone monohydrate (DSAL,10 µM. Results: IGlu was observed in EAAT1 and in EAAT2 expressing oocytes but not in water injected oocytes. In both, EAAT1 and EAAT2 expressing oocytes IGlu was significantly increased by treatment with soluble ß-Klotho protein, an effect reversed by DSAL. Treatment with ß-klotho protein increased significantly the maximal transport rate without significantly modifying the affinity of the carriers. Conclusion: ß-Klotho up-regulates the excitatory glutamate transporters EAAT1 and EAAT2 and thus participates in the regulation of neuronal excitation.

Excitatory amino acid transporters EAAT-1 and EAAT-2 in temporal lobe and hippocampus in intractable temporal lobe epilepsy

DEFF Research Database (Denmark)

Sarac, Sinan; Afzal, Shoaib; Broholm, Helle

2009-01-01

Intractable temporal lobe epilepsy (TLE) is an invalidating disease and many patients are resistant to medical treatment. Increased glutamate concentration has been found in epileptogenic foci and may induce local over-excitation and cytotoxicity; one of the proposed mechanisms involves reduced...... extra-cellular clearance of glutamate by excitatory amino acid transporters (EAAT-1 to EAAT-5). EAAT-1 and EAAT-2 are mainly expressed on astroglial cells for the reuptake of glutamate from the extra-cellular space. We have studied the expression of EAAT-1 and EAAT-2 in the hippocampus and temporal lobe...

Biochemical characterization of an autoradiographic method for studying excitatory amino acid receptors using L-[3H]glutamate

International Nuclear Information System (INIS)

Cincotta, M.; Summers, R.J.; Beart, P.M.

1989-01-01

A method was developed for radiolabeling excitatory amino acid receptors of rat brain with L-[ 3 H]glutamate. Effective labeling of glutamate receptors in slide-mounted 10-microns sections was obtained using a low incubation volume (0.15 ml) and rapid washing: a procedure where high ligand concentrations were achieved with minimal waste. Saturation experiments using [ 3 H]glutamate revealed a single binding site of micromolar affinity. The Bmax was trebled in the presence of Ca2+ (2.5 mM) and Cl- (20 mM) with no change in the Kd. Binding was rapid, saturable, stereospecific, and sensitive to glutamate receptor agonists. The proportions of [ 3 H]glutamate binding sensitive to N-methyl-D-aspartate (NMDA), kainate, and alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) were 34, 54, and 51%, respectively. NMDA inhibited binding at a distinct subset of L-[ 3 H]glutamate sites, whereas AMPA and kainate competed for some common sites. Labeling of sections with L-[ 3 H]glutamate in the presence of the selective agonists allowed autoradiographic visualization of glutamate receptor subtypes in brain tissue

Excitatory amino acid receptor antagonists

DEFF Research Database (Denmark)

Johansen, T N; Frydenvang, Karla Andrea; Ebert, B

1997-01-01

We have previously shown that (RS)-2-amino-2-(5-tert-butyl-3-hydroxyisoxazol-4-yl)acetic acid (ATAA) is an antagonist at N-methyl-D-aspartic acid (NMDA) and (RS)-2-amino-3-(3-hydroxy-5-methylisoxazol-4-yl)propionic acid (AMPA) receptors. We have now resolved ATAA via diastereomeric salt formation......)-phenylethylamine salt of N-BOC-(R)-ATAA. Like ATAA, neither (R)- nor (S)-ATAA significantly affected (IC50 > 100 microM) the receptor binding of tritiated AMPA, kainic acid, or (RS)-3-(2-carboxypiperazin-4-yl)propyl-1-phosphonic acid, the latter being a competitive NMDA antagonist. Electrophysiological experiments......, using the rat cortical wedge preparation, showed the NMDA antagonist effect as well as the AMPA antagonist effect of ATAA to reside exclusively in the (R)-enantiomer (Ki = 75 +/- 5 microM and 57 +/- 1 microM, respectively). Neither (R)- nor (S)-ATAA significantly reduced kainic acid-induced excitation...

Glutathione in Cellular Redox Homeostasis: Association with the Excitatory Amino Acid Carrier 1 (EAAC1

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Koji Aoyama

2015-05-01

Full Text Available Reactive oxygen species (ROS are by-products of the cellular metabolism of oxygen consumption, produced mainly in the mitochondria. ROS are known to be highly reactive ions or free radicals containing oxygen that impair redox homeostasis and cellular functions, leading to cell death. Under physiological conditions, a variety of antioxidant systems scavenge ROS to maintain the intracellular redox homeostasis and normal cellular functions. This review focuses on the antioxidant system’s roles in maintaining redox homeostasis. Especially, glutathione (GSH is the most important thiol-containing molecule, as it functions as a redox buffer, antioxidant, and enzyme cofactor against oxidative stress. In the brain, dysfunction of GSH synthesis leading to GSH depletion exacerbates oxidative stress, which is linked to a pathogenesis of aging-related neurodegenerative diseases. Excitatory amino acid carrier 1 (EAAC1 plays a pivotal role in neuronal GSH synthesis. The regulatory mechanism of EAAC1 is also discussed.

Up-Regulation of Excitatory Amino Acid Transporters EAAT3 and EAAT4 by Lithium Sensitive Glycogen Synthase Kinase GSK3ß

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Abeer Abousaab

2016-12-01

Full Text Available Background: Cellular uptake of glutamate by the excitatory amino-acid transporters (EAATs decreases excitation and thus participates in the regulation of neuroexcitability. Kinases impacting on neuronal function include Lithium-sensitive glycogen synthase kinase GSK3ß. The present study thus explored whether the activities of EAAT3 and/or EAAT4 isoforms are sensitive to GSK3ß. Methods: cRNA encoding wild type EAAT3 (SLC1A1 or EAAT4 (SLC1A6 was injected into Xenopus oocytes without or with additional injection of cRNA encoding wild type GSK3ß or the inactive mutant K85AGSK3ß. Dual electrode voltage clamp was performed in order to determine glutamate-induced current (IEAAT. Results: Appreciable IEAAT was observed in EAAT3 or EAAT4 expressing but not in water injected oocytes. IEAAT was significantly increased by coexpression of GSK3ß but not by coexpression of K85AGSK3ß. Coexpression of GSK3ß increased significantly the maximal IEAAT in EAAT3 or EAAT4 expressing oocytes, without significantly modifying apparent affinity of the carriers. Lithium (1 mM exposure for 24 hours decreased IEAAT in EAAT3 and GSK3ß expressing oocytes to values similar to IEAAT in oocytes expressing EAAT3 alone. Lithium did not significantly modify IEAAT in oocytes expressing EAAT3 without GSK3ß. Conclusions: Lithium-sensitive GSK3ß is a powerful regulator of excitatory amino acid transporters EAAT3 and EAAT4.

Probing for improved potency and in vivo bioavailability of excitatory amino acid transporter subtype 1 inhibitors UCPH-101 and UCPH-102: Design, synthesis and pharmacological evaluation of substituted 7-biphenyl analogs

DEFF Research Database (Denmark)

Erichsen, Mette Norman; Hansen, J; Artacho Ruiz, Jose

2014-01-01

Uptake of the major excitatory neurotransmitter in the CNS, (S)-glutamate, is mediated by a family of excitatory amino acid transporters (EAAT). Previously we have explored the structure-activity relationship (SAR) of a series of EAAT1 selective inhibitors, leading to the development of the potent...... were designed, synthesized and characterized pharmacologically at EAAT1-3 in a [(3)H]-D-aspartate uptake assay. Most notably, the potent EAAT1 inhibition displayed of UCPH-101 and UCPH-102 was retained in analog 1d in which the napht-1-yl group in the 7-position of UCPH-102 has been replaced by an o...

Stress activates pronociceptive endogenous opioid signalling in DRG neurons during chronic colitis.

Science.gov (United States)

Guerrero-Alba, Raquel; Valdez-Morales, Eduardo E; Jimenez-Vargas, Nestor N; Lopez-Lopez, Cintya; Jaramillo-Polanco, Josue; Okamoto, Takanobu; Nasser, Yasmin; Bunnett, Nigel W; Lomax, Alan E; Vanner, Stephen J

2017-12-01

Psychological stress accompanies chronic inflammatory diseases such as IBD, and stress hormones can exacerbate pain signalling. In contrast, the endogenous opioid system has an important analgesic action during chronic inflammation. This study examined the interaction of these pathways. Mouse nociceptive dorsal root ganglia (DRG) neurons were incubated with supernatants from segments of inflamed colon collected from patients with chronic UC and mice with dextran sodium sulfate (cDSS)-induced chronic colitis. Stress effects were studied by adding stress hormones (epinephrine and corticosterone) to dissociated neurons or by exposing cDSS mice to water avoidance stress. Changes in excitability of colonic DRG nociceptors were measured using patch clamp and Ca 2+ imaging techniques. Supernatants from patients with chronic UC and from colons of mice with chronic colitis caused a naloxone-sensitive inhibition of neuronal excitability and capsaicin-evoked Ca 2+ responses. Stress hormones decreased signalling induced by human and mouse supernatants. This effect resulted from stress hormones signalling directly to DRG neurons and indirectly through signalling to the immune system, leading to decreased opioid levels and increased acute inflammation. The net effect of stress was a change endogenous opioid signalling in DRG neurons from an inhibitory to an excitatory effect. This switch was associated with a change in G protein-coupled receptor excitatory signalling to a pathway sensitive to inhibitors of protein kinase A-protein, phospholipase C-protein and G protein βϒ subunits. Stress hormones block the inhibitory actions of endogenous opioids and can change the effect of opioid signalling in DRG neurons to excitation. Targeting these pathways may prevent heavy opioid use in IBD. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.

Excitatory amino acids in epilepsy and potential novel therapies.

Science.gov (United States)

Meldrum, B S

1992-07-01

Evidence that an abnormality of excitatory neurotransmission may contribute to the epileptic phenomena in various animal and human syndromes is reviewed. Altered glutamate transport or metabolism may be a contributory factor in some genetic syndromes and enhanced responsiveness to activation of NMDA receptors may be significant in various acquired forms of epilepsy. Decreasing glutamatergic neurotransmission provides a rational therapeutic approach to epilepsy. Potent anticonvulsant effects are seen with the acute administration of NMDA antagonists in a wide range of animal models. Some competitive antagonists acting at the NMDA/glutamate site show prolonged anticonvulsant activity following oral administration at doses free of motor side effects and appear suitable for clinical trial.

Interlaminar and lateral excitatory amino acid connections in the striate cortex of monkey

International Nuclear Information System (INIS)

Kisvarday, Z.F.; Cowey, A.; Smith, A.D.; Somogyi, P.

1989-01-01

The intrinsic excitatory amino acid pathways within the striate cortex of monkeys were studied by autoradiographic detection of retrogradely labeled somata following microinjections of D-3H-aspartate (D-3H-Asp) into different layers. The labeled amino acid was selectively accumulated by subpopulations of neurons and, to a small extent, by glial cells, the latter mainly in the supragranular layers. Immunocytochemical detection of neurons containing GABA showed that, apart from a few cells exclusively in layer I, GABAergic neurons do not accumulate D-3H-Asp. Several lines of evidence suggest that D-3H-Asp uptake occurred only at nerve terminals; thus, the pattern of perikaryal labeling allowed the delineation of interlaminar and lateral projections. Neurons in layer I probably project laterally, and layer I receives wide-ranging projections from layer IVB and layer V from cells up to 1300 microns laterally. Some neurons in layer II send a focused projection to lower layer VI. Some neurons in layers II/III project up to 1 mm laterally within their own layer, but relatively few neurons can be labeled in these projections. Similarly, in layers II/III few neurons can be retrogradely labeled from layers V and upper VI, and this projection is organized such that cells closer to the pia project deeper in layer V/VI. The connections of layer IVA could not be revealed separately because of the difficulty of confining injections to this thin sublamina. Neurons in layer IVB project up to 1300 microns within IVB itself. A small number of cells from IVB also project to layers III, IVC-alpha, V, and VI with much more restricted lateral spread. Neurons in upper IVC-alpha send axons to layer IVB with at least 600-800 microns lateral spread. Neurons in lower IVC-alpha/upper IVC-beta project to layer III with at least 300-500 microns lateral spread

Interlaminar and lateral excitatory amino acid connections in the striate cortex of monkey

Energy Technology Data Exchange (ETDEWEB)

Kisvarday, Z.F.; Cowey, A.; Smith, A.D.; Somogyi, P.

1989-02-01

The intrinsic excitatory amino acid pathways within the striate cortex of monkeys were studied by autoradiographic detection of retrogradely labeled somata following microinjections of D-3H-aspartate (D-3H-Asp) into different layers. The labeled amino acid was selectively accumulated by subpopulations of neurons and, to a small extent, by glial cells, the latter mainly in the supragranular layers. Immunocytochemical detection of neurons containing GABA showed that, apart from a few cells exclusively in layer I, GABAergic neurons do not accumulate D-3H-Asp. Several lines of evidence suggest that D-3H-Asp uptake occurred only at nerve terminals; thus, the pattern of perikaryal labeling allowed the delineation of interlaminar and lateral projections. Neurons in layer I probably project laterally, and layer I receives wide-ranging projections from layer IVB and layer V from cells up to 1300 microns laterally. Some neurons in layer II send a focused projection to lower layer VI. Some neurons in layers II/III project up to 1 mm laterally within their own layer, but relatively few neurons can be labeled in these projections. Similarly, in layers II/III few neurons can be retrogradely labeled from layers V and upper VI, and this projection is organized such that cells closer to the pia project deeper in layer V/VI. The connections of layer IVA could not be revealed separately because of the difficulty of confining injections to this thin sublamina. Neurons in layer IVB project up to 1300 microns within IVB itself. A small number of cells from IVB also project to layers III, IVC-alpha, V, and VI with much more restricted lateral spread. Neurons in upper IVC-alpha send axons to layer IVB with at least 600-800 microns lateral spread. Neurons in lower IVC-alpha/upper IVC-beta project to layer III with at least 300-500 microns lateral spread.

Miniature excitatory synaptic currents in cultured hippocampal neurons.

Science.gov (United States)

Finch, D M; Fisher, R S; Jackson, M B

1990-06-04

We performed patch clamp recordings in the whole cell mode from cultured embryonic mouse hippocampal neurons. In bathing solutions containing tetrodotoxin (TTX), the cells showed spontaneous inward currents (SICs) ranging in size from 1 to 100 pA. Several observations indicated that the SICs were miniature excitatory synaptic currents mediated primarily by non-NMDA (N-methyl-D-aspartate) excitatory amino acid receptors: the rising phase of SICs was fast (1 ms to half amplitude at room temperature) and smooth, suggesting unitary events. The SICs were blocked by the broad-spectrum glutamate receptor antagonist gamma-D-glutamylglycine (DGG), but not by the selective NMDA-receptor antagonist D-2-amino-5-phosphonovaleric acid (5-APV). SICs were also blocked by desensitizing concentrations of quisqualate. Incubating cells in tetanus toxin, which blocks exocytotic transmitter release, eliminated SICs. The presence of SICs was consistent with the morphological arrangement of glutamatergic innervation in the cell cultures demonstrated immunohistochemically. Spontaneous outward currents (SOCs) were blocked by bicuculline and presumed to be mediated by GABAA receptors. This is consistent with immunohistochemical demonstration of GABAergic synapses. SIC frequency was increased in a calcium dependent manner by bathing the cells in a solution high in K+, and application of the dihydropyridine L-type calcium channel agonist BAY K 8644 increased the frequency of SICs. Increases in SIC frequency produced by high K+ solutions were reversed by Cd2+ and omega-conotoxin GVIA, but not by the selective L-type channel antagonist nimodipine. This suggested that presynaptic L-type channels were in a gating mode that was not blocked by nimodipine, and/or that another class of calcium channel makes a dominant contribution to excitatory transmitter release.

Pharmacological characterization of human excitatory amino acid transporters EAAT1, EAAT2 and EAAT3 in a fluorescence-based membrane potential assay

DEFF Research Database (Denmark)

Jensen, Anders A.; Bräuner-Osborne, Hans

2004-01-01

We have expressed the human excitatory amino acid transporters EAAT1, EAAT2 and EAAT3 stably in HEK293 cells and characterized the transporters pharmacologically in a conventional [(3) H]-d-aspartate uptake assay and in a fluorescence-based membrane potential assay, the FLIPR Membrane Potential...... (FMP) assay. The K(m) and K(i) values obtained for 12 standard EAAT ligands at EAAT1, EAAT2 and EAAT3 in the FMP assay correlated well with the K(i) values obtained in the [(3) H]-d-aspartate assay (r(2) values of 0.92, 0.92, and 0.95, respectively). Furthermore, the pharmacological characteristics...

Neuromodulation by Mg2+ and polyamines of excitatory amino acid currents in rodent neurones in culture.

Science.gov (United States)

Kumamoto, E

1996-12-01

Excitatory amino-acid currents in rodent central neurones are mediated by the activation of glutamate receptors. Ionotropic types of the receptors are divided into alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionate (AMPA), kainate and N-methyl-D-aspartate (NMDA) receptors, and the former two are collectively called non-NMDA receptors. The NMDA receptor is modulated by a number of endogenous neuromodulators including Mg2+, polyamines, glycine and protons in extracellular solutions. Although it has been generally thought that each of the neuromodulators acts on a distinct site in the NMDA receptor, recent studies have revealed that these actions may be not necessarily independent of each other. The NMDA receptor response is not only inhibited but also potentiated by Mg2+, and the latter action is due to an interaction of a Mg2+ site with either glycine- or proton-binding site. In the presence of polyamines, a tonic inhibition by protons of the NMDA receptor response is relieved, resulting in a potentiation of the response. Alternatively, it has been recently revealed that there are some subtypes of non-NMDA receptors which are negatively modulated by polyamines in either extra- or intra cellular solutions. The difference in polyamine sensitivity among non-NMDA receptors is attributed to a distinction in their constituted subunits. The inhibition of non-NMDA receptor by intracellular polyamines results in inward rectification of the current-voltage relation which is not seen for polyamine-insensitive ones. This polyamine action is not mimicked by intracellular Mg2+.

Prenatal ethanol exposure reduces the effects of excitatory amino acids in the rat hippocampus

International Nuclear Information System (INIS)

Noble, E.P.; Ritchie, T.

1989-01-01

Chronic alcohol ingestion during pregnancy can lead to the Fetal Alcohol Syndrome (FAS), a disorder marked by learning disabilities. A rat model of FAS was used by introducing pregnant Sprague-Dawley rats to a liquid diet containing 35% ethanol-derived calories (E), while a second group was pair-fed an isocaloric liquid diet without ethanol (P). A third group of pregnant dams received ad libitum lab chow (C). At parturition, pups from the E and P groups were cross fostered by C mothers and all groups received lab chow. During adulthood, male offspring were sacrificed and hippocampal and prefrontal cortical slices were prelabeled with [3H]inositol. Phosphoinositide (PI) hydrolysis was determined by measuring the accumulation of [3H]inositol phosphates in the presence of LiCl in response to activation of various excitatory amino acid (EAA) receptors. In hippocampal slices, ibotenate- and quisqualate-induced PI hydrolysis was reduced in E compared to P and C animals. Moreover, the inhibitory effect of N-methyl-D-aspartate (NMDA) on carbachol-induced PI hydrolysis, evident in P and C animals, was completely abolished in the hippocampus of E animals. In contrast, in the prefrontal cerebral cortex, this inhibitory effect of NMDA prevailed even in the E animals. The evidence suggests that prenatal ethanol exposure alters the activity of EAA receptors in the hippocampal generation of 2nd messengers

4,4-Dimethyl- and diastereomeric 4-hydroxy-4-methyl-(2S)-glutamate analogues display distinct pharmacological profiles at ionotropic glutamate receptors and excitatory amino acid transporters

DEFF Research Database (Denmark)

Bunch, Lennart; Pickering, Darryl S; Gefflaut, Thierry

2009-01-01

this approach has provided important insight into the structure-activity relationships (SAR) for ionotropic and metabotropic glutamate receptors (iGluRs and mGluRs), as well as the excitatory amino acid transporters (EAATs). In this work, three 4,4-disubstituted Glu analogues 1-3, which are hybrid structures......Subtype-selective ligands are of great interest to the scientific community, as they provide a tool for investigating the function of one receptor or transporter subtype when functioning in its native environment. Several 4-substituted (S)-glutamate (Glu) analogues were synthesized, and altogether...

Designing Novel Nanoformulations Targeting Glutamate Transporter Excitatory Amino Acid Transporter 2: Implications in Treating Drug Addiction.

Science.gov (United States)

Rao, Pss; Yallapu, Murali M; Sari, Youssef; Fisher, Paul B; Kumar, Santosh

Chronic drug abuse is associated with elevated extracellular glutamate concentration in the brain reward regions. Deficit of glutamate clearance has been identified as a contributing factor that leads to enhanced glutamate concentration following extended drug abuse. Importantly, normalization of glutamate level through induction of glutamate transporter 1 (GLT1)/ excitatory amino acid transporter 2 (EAAT2) expression has been described in several in vivo studies. GLT1 upregulators including ceftriaxone, a beta-lactam antibiotic, have been effective in attenuating drug-seeking and drug-consumption behavior in rodent models. However, potential obstacles toward clinical translation of GLT1 (EAAT2) upregulators as treatment for drug addiction might include poor gastrointestinal absorption, serious peripheral adverse effects, and/or suboptimal CNS concentrations. Given the growing success of nanotechnology in targeting CNS ailments, nanoformulating known GLT1 (EAAT2) upregulators for selective uptake across the blood brain barrier presents an ideal therapeutic approach for treating drug addiction. In this review, we summarize the results obtained with promising GLT1 (EAAT2) inducing compounds in animal models recapitulating drug addiction. Additionally, the various nanoformulations that can be employed for selectively increasing the CNS bioavailability of GLT1 (EAAT2) upregulators are discussed. Finally, the applicability of GLT1 (EAAT2) induction via central delivery of drug-loaded nanoformulations is described.

Stereoselective chemoenzymatic synthesis of the four stereoisomers of l-2-(2-carboxycyclobutyl)glycine and pharmacological characterization at human excitatory amino acid transporter subtypes 1, 2, and 3

DEFF Research Database (Denmark)

Faure, Sophie; Jensen, Anders A.; Maurat, Vincent

2006-01-01

The four stereoisomers of l-2-(2-carboxycyclobutyl)glycine, l-CBG-I, l-CBG-II, l-CBG-III, and l-CBG-IV, were synthesized in good yield and high enantiomeric excess, from the corresponding cis and trans-2-oxalylcyclobutanecarboxylic acids 5 and 6 using the enzymes aspartate aminotransferase (AAT......) and branched chain aminotransferase (BCAT) from Escherichia coli. The four stereoisomeric compounds were evaluated as potential ligands for the human excitatory amino acid transporters, subtypes 1, 2, and 3 (EAAT1, EAAT2, and EAAT3) in the FLIPR membrane potential assay. While the one trans-stereoisomer, l...

Amino acid neurotransmitters and new approaches to anticonvulsant drug action.

Science.gov (United States)

Meldrum, B

1984-01-01

Amino acids provide the most universal and important inhibitory (gamma-aminobutyric acid (GABA), glycine) and excitatory (glutamate, aspartate, cysteic acid, cysteine sulphinic acid) neurotransmitters in the brain. An anticonvulsant action may be produced (1) by enhancing inhibitory (GABAergic) processes, and (2) by diminishing excitatory transmission. Possible pharmacological mechanisms for enhancing GABA-mediated inhibition include (1) GABA agonist action, (2) GABA prodrugs, (3) drugs facilitating GABA release from terminals, (4) inhibition of GABA-transaminase, (5) allosteric enhancement of the efficacy of GABA at the receptor complex, (6) direction action on the chloride ionophore, and (7) inhibition of GABA reuptake. Examples of these approaches include the use of irreversible GABA-transaminase inhibitors, such as gamma-vinyl GABA, and the development of anticonvulsant beta-carbolines that interact with the "benzodiazepine receptor." Pharmacological mechanisms for diminishing excitatory transmission include (1) enzyme inhibitors that decrease the maximal rate of synthesis of glutamate or aspartate, (2) drugs that decrease the synaptic release of glutamate or aspartate, and (3) drugs that block the post-synaptic action of excitatory amino acids. Compounds that selectively antagonise excitation due to dicarboxylic amino acids have recently been developed. Those that selectively block excitation produced by N-methyl-D-aspartate (and aspartate) have proved to be potent anticonvulsants in many animal models of epilepsy. This provides a novel approach to the design of anticonvulsant drugs.

Interlaminar and lateral excitatory amino acid connections in the striate cortex of monkey.

Science.gov (United States)

Kisvarday, Z F; Cowey, A; Smith, A D; Somogyi, P

1989-02-01

The intrinsic excitatory amino acid pathways within the striate cortex of monkeys were studied by autoradiographic detection of retrogradely labeled somata following microinjections of D-3H-aspartate (D-3H-Asp) into different layers. The labeled amino acid was selectively accumulated by subpopulations of neurons and, to a small extent, by glial cells, the latter mainly in the supragranular layers. Immunocytochemical detection of neurons containing GABA showed that, apart from a few cells exclusively in layer I, GABAergic neurons do not accumulate D-3H-Asp. Several lines of evidence suggest that D-3H-Asp uptake occurred only at nerve terminals; thus, the pattern of perikaryal labeling allowed the delineation of interlaminar and lateral projections. Neurons in layer I probably project laterally, and layer I receives wide-ranging projections from layer IVB and layer V from cells up to 1300 microns laterally. Some neurons in layer II send a focused projection to lower layer VI. Some neurons in layers II/III project up to 1 mm laterally within their own layer, but relatively few neurons can be labeled in these projections. Similarly, in layers II/III few neurons can be retrogradely labeled from layers V and upper VI, and this projection is organized such that cells closer to the pia project deeper in layer V/VI. The connections of layer IVA could not be revealed separately because of the difficulty of confining injections to this thin sublamina. Neurons in layer IVB project up to 1300 microns within IVB itself. A small number of cells from IVB also project to layers III, IVC-alpha, V, and VI with much more restricted lateral spread. Neurons in upper IVC-alpha send axons to layer IVB with at least 600-800 microns lateral spread. Neurons in lower IVC-alpha/upper IVC-beta project to layer III with at least 300-500 microns lateral spread. The bottom 50-80 microns of layer IVC-beta contains neurons with a very focused projection, apparently exclusively to the layer III

Sustained Morphine Administration Induces TRPM8-Dependent Cold Hyperalgesia.

Science.gov (United States)

Gong, Kerui; Jasmin, Luc

2017-02-01

It is not uncommon for patients chronically treated with opioids to exhibit opioid-induced hyperalgesia, and this has been widely reported clinically and experimentally. The molecular substrate for this hyperalgesia is multifaceted, and associated with a complex neural reorganization even in the periphery. For instance, we have recently shown that chronic morphine-induced heat hyperalgesia is associated with an increased expression of GluN2B containing N-methyl-D-aspartate receptors, as well as of the neuronal excitatory amino acid transporter 3/excitatory amino acid carrier 1, in small-diameter primary sensory neurons only. Cold allodynia is also a common complaint of patients chronically treated with opioids, yet its molecular mechanisms remain to be understood. Here we present evidence that the cold sensor TRPM8 channel is involved in opioid-induced hyperalgesia. After 7 days of morphine administration, we observed an upregulation of TRPM8 channels using patch clamp recording on sensory neurons and Western blot analysis on dorsal root ganglia. The selective TRPM8 antagonist RQ-00203078 blocked cold hyperalgesia in morphine-treated rats. Also, TRPM8 knockout mice failed to develop cold hyperalgesia after chronic administration of morphine. Our results show that chronic morphine upregulates TRPM8 channels, which is in contrast with the previous finding that acute morphine triggers TRPM8 internalization. Patients receiving chronic opioid are sensitive to cold. We show in mice and rats that sustained morphine administration induces cold hyperalgesia and an upregulation of TRPM8. Knockout or selectively blocking TRPM8 reduces morphine-induced cold hyperalgesia suggesting TRPM8 is regulated by opioids. Copyright © 2016 American Pain Society. Published by Elsevier Inc. All rights reserved.

Molecular characterization of opioid receptors

Energy Technology Data Exchange (ETDEWEB)

Howard, A.D.

1986-01-01

The aim of this research was to purify and characterize active opioid receptors and elucidate molecular aspects of opioid receptor heterogeneity. Purification to apparent homogeneity of an opioid binding protein from bovine caudate was achieved by solubilization in the non-ionic detergent, digitonin, followed by sequential chromatography on the opiate affinity matrix, ..beta..-naltrexylethylenediamine-CH-Sepharose 4B, and on the lectine affinity matrix, wheat germ agglutinin-agarose. Polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate (SDS-PAGE) followed by autoradiography revealed that radioiodinated purified receptor gave a single band. Purified receptor preparations showed a specific activity of 12,000-15,000 fmol of opiate bound per mg of protein. Radioiodinated human beta-endorphin (/sup 125/I-beta-end/sub H/) was used as a probe to investigate the ligand binding subunits of mu and delta opioid receptors. /sup 125/I-beta-end/sub H/ was shown to bind to a variety of opioid receptor-containing tissues with high affinity and specificity with preference for mu and delta sites, and with little, if any, binding to kappa sites. Affinity crosslinking techniques were employed to covalently link /sup 125/I-beta-end/sub H/ to opioid receptors, utilizing derivatives of bis-succinimidyl esters that are bifunctional crosslinkers with specificities for amino and sulfhydryl groups. This, and competition experiments with high type-selective ligands, permitted the assignment of two labeled peptides to their receptor types, namely a peptide of M/sub r/ = 65,000 for mu receptors and one of M/sub r/ = 53,000 for delta receptors.

The excitatory amino acid receptor antagonist MK-801 prevents the hypersensitivity induced by spinal cord ischemia in the rat

International Nuclear Information System (INIS)

Hao, J.X.; Xu, X.J.; Aldskogius, H.; Seiger, A.; Wiesenfeld-Hallin, Z.

1991-01-01

Protection by the NMDA receptor antagonist MK-801 against transient spinal cord ischemia-induced hypersensitivity was studied in rats. The spinal ischemia was initiated by vascular occlusion resulting from the interaction between the photosensitizing dye Erythrosin B and an argon laser beam. The hypersensitivity, termed allodynia, where the animals reacted by vocalization to nonnoxious mechanical stimuli in the flank area, was consistently observed during several days after induction of the ischemia. Pretreatment with MK-801 (0.1-0.5 mg/kg, iv) 10 min before laser irradiation dose dependently prevented the occurrence of allodynia. The neuroprotective effect of MK-801 was not reduced by maintaining normal body temperature during and after irradiation. There was a significant negative correlation between the delay in the administration of MK-801 after irradiation and the protective effect of the drug. Histological examination revealed slight morphological damage in the spinal cord in 38% of control rats after 1 min of laser irradiation without pretreatment with MK-801. No morphological abnormalities were observed in rats after pretreatment with MK-801 (0.5 mg/kg). The present results provide further evidence for the involvement of excitatory amino acids, through activation of the NMDA receptor, in the development of dysfunction following ischemic trauma to the spinal cord

Plasticity of cortical excitatory-inhibitory balance.

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Froemke, Robert C

2015-07-08

Synapses are highly plastic and are modified by changes in patterns of neural activity or sensory experience. Plasticity of cortical excitatory synapses is thought to be important for learning and memory, leading to alterations in sensory representations and cognitive maps. However, these changes must be coordinated across other synapses within local circuits to preserve neural coding schemes and the organization of excitatory and inhibitory inputs, i.e., excitatory-inhibitory balance. Recent studies indicate that inhibitory synapses are also plastic and are controlled directly by a large number of neuromodulators, particularly during episodes of learning. Many modulators transiently alter excitatory-inhibitory balance by decreasing inhibition, and thus disinhibition has emerged as a major mechanism by which neuromodulation might enable long-term synaptic modifications naturally. This review examines the relationships between neuromodulation and synaptic plasticity, focusing on the induction of long-term changes that collectively enhance cortical excitatory-inhibitory balance for improving perception and behavior.

Excitatory amino acid receptors mediate asymmetry and lateralization in the descending cardiovascular pathways from the dorsomedial hypothalamus.

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Carlos Henrique Xavier

Full Text Available The dorsomedial hypothalamus (DMH and lateral/dorsolateral periaqueductal gray (PAG are anatomically and functionally connected. Both the DMH and PAG depend on glutamatergic inputs for activation. We recently reported that removal of GABA-ergic tone in the unilateral DMH produces: asymmetry, that is, a right- (R- sided predominance in cardiac chronotropism, and lateralization, that is, a greater increase in ipsilateral renal sympathetic activity (RSNA. In the current study, we investigated whether excitatory amino acid (EAA receptors in the DMH-PAG pathway contribute to the functional interhemispheric difference. In urethane (1.2 to 1.4 g/kg, i.p. anesthetized rats, we observed that: (i nanoinjections of N-methyl D-aspartate (NMDA 100 pmol/100 nl into the unilateral DMH produced the same right-sided predominance in the control of cardiac chronotropy, (ii nanoinjections of NMDA into the ipsilateral DMH or PAG evoked lateralized RSNA responses, and (iii blockade of EAA receptors in the unilateral DMH attenuated the cardiovascular responses evoked by injection of NMDA into either the R- or left- (L- PAG. In awake rats, nanoinjection of kynurenic acid (1 nmol/100 nL into the L-DMH or R- or L-PAG attenuated the tachycardia evoked by air stress. However, the magnitude of stress-evoked tachycardia was smallest when the EAA receptors of the R-DMH were blocked. We conclude that EAA receptors contribute to the right-sided predominance in cardiac chronotropism. This interhemispheric difference that involves EAA receptors was observed in the DMH but not in the PAG.

Functional characteristics of the naked mole rat μ-opioid receptor.

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Melanie Busch-Dienstfertig

Full Text Available While humans and most animals respond to µ-opioid receptor (MOR agonists with analgesia and decreased aggression, in the naked mole rat (NMR opioids induce hyperalgesia and severe aggression. Single nucleotide polymorphisms in the human mu-opioid receptor gene (OPRM1 can underlie altered behavioral responses to opioids. Therefore, we hypothesized that the primary structure of the NMR MOR may differ from other species. Sequencing of the NMR oprm1 revealed strong homology to other mammals, but exposed three unique amino acids that might affect receptor-ligand interactions. The NMR and rat oprm1 sequences were cloned into mammalian expression vectors and transfected into HEK293 cells. Radioligand binding and 3'-5'-cyclic adenosine monophosphate (cAMP enzyme immunoassays were used to compare opioid binding and opioid-mediated cAMP inhibition. At normalized opioid receptor protein levels we detected significantly lower [3H]DAMGO binding to NMR compared to rat MOR, but no significant difference in DAMGO-induced cAMP inhibition. Strong DAMGO-induced MOR internalization was detectable using radioligand binding and confocal imaging in HEK293 cells expressing rat or NMR receptor, while morphine showed weak or no effects. In summary, we found minor functional differences between rat and NMR MOR suggesting that other differences e.g. in anatomical distribution of MOR underlie the NMR's extreme reaction to opioids.

Piracetam ameliorated oxygen and glucose deprivation-induced injury in rat cortical neurons via inhibition of oxidative stress, excitatory amino acids release and P53/Bax.

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He, Zhi; Hu, Min; Zha, Yun-hong; Li, Zi-cheng; Zhao, Bo; Yu, Ling-ling; Yu, Min; Qian, Ying

2014-05-01

Our previous work has demonstrated that piracetam inhibited the decrease in amino acid content induced by chronic hypoperfusion, ameliorated the dysfunction of learning and memory in a hypoperfusion rat model, down-regulated P53, and BAX protein, facilitated the synaptic plasticity, and may be helpful in the treatment of vascular dementia. To explore the precise mechanism, the present study further evaluated effects of piracetam on Oxygen and glucose deprivation (OGD)-induced neuronal damage in rat primary cortical cells. The addition of piracetam to the cultured cells 12 h before OGD for 4 h significantly reduced neuronal damage as determined by MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay and lactate dehydrogenase release experiments. Piracetam also lowered the levels of malondialdehyde, nitrogen monoxidum, and xanthine oxidase which was increased in the OGD cells, and enhanced the activities of superoxide dismutase and glutathione peroxidase, which were decreased in the OGD cells. We also demonstrated that piracetam could decrease glutamate and aspartate release when cortical cells were subjected to OGD. Furthermore, Western blot study demonstrated that piracetam attenuated the increased expression of P53 and BAX protein in OGD cells. These observations demonstrated that piracetam reduced OGD-induced neuronal damage by inhibiting the oxidative stress and decreasing excitatory amino acids release and lowering P53/Bax protein expression in OGD cells.

Mechanism of Transport Modulation by an Extracellular Loop in an Archaeal Excitatory Amino Acid Transporter (EAAT) Homolog*

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Mulligan, Christopher; Mindell, Joseph A.

2013-01-01

Secondary transporters in the excitatory amino acid transporter family terminate glutamatergic synaptic transmission by catalyzing Na+-dependent removal of glutamate from the synaptic cleft. Recent structural studies of the aspartate-specific archaeal homolog, GltPh, suggest that transport is achieved by a rigid body, piston-like movement of the transport domain, which houses the substrate-binding site, between the extracellular and cytoplasmic sides of the membrane. This transport domain is connected to an immobile scaffold by three loops, one of which, the 3–4 loop (3L4), undergoes substrate-sensitive conformational change. Proteolytic cleavage of the 3L4 was found to abolish transport activity indicating an essential function for this loop in the transport mechanism. Here, we demonstrate that despite the presence of fully cleaved 3L4, GltPh is still able to sample conformations relevant for transport. Optimized reconstitution conditions reveal that fully cleaved GltPh retains some transport activity. Analysis of the kinetics and temperature dependence of transport accompanied by direct measurements of substrate binding reveal that this decreased transport activity is not due to alteration of the substrate binding characteristics but is caused by the significantly reduced turnover rate. By measuring solute counterflow activity and cross-link formation rates, we demonstrate that cleaving 3L4 severely and specifically compromises one or more steps contributing to the movement of the substrate-loaded transport domain between the outward- and inward-facing conformational states, sparing the equivalent step(s) during the movement of the empty transport domain. These results reveal a hitherto unknown role for the 3L4 in modulating an essential step in the transport process. PMID:24155238

Opioid adjuvant strategy: improving opioid effectiveness.

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Bihel, Frédéric

2016-01-01

Opioid analgesics continue to be the mainstay of pharmacologic treatment of moderate to severe pain. Many patients, particularly those suffering from chronic pain, require chronic high-dose analgesic therapy. Achieving clinical efficacy and tolerability of such treatment regimens is hampered by the appearance of opioid-induced side effects such as tolerance, hyperalgesia and withdrawal syndrome. Among the therapeutic options to improve the opioid effectiveness, this current review focuses on strategies combining opioids to other drugs that can modulate opioid-mediated effects. We will discuss about experimental evidences reported for several potential opioid adjuvants, including N-methyl-D-aspartate receptor antagonists, 5-HT7 agonists, sigma-1 antagonists, I2-R ligands, cholecystokinin antagonists, neuropeptide FF-R antagonists and toll-like receptor 4 antagonists.

Low efficacy of non-opioid drugs in opioid withdrawal symptoms.

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Hermann, Derik; Klages, Eckard; Welzel, Helga; Mann, Karl; Croissant, Bernhard

2005-06-01

Opioid withdrawal, stress or cues associated with opioid consumption can induce opioid craving. If opioids are not available, opioid-dependent patients usually search for alternative drugs. Because several non-opioid drugs stimulate the endogenous opioidergic system, this concept may explain their frequent use by opioid-dependent patients. We hypothesized that non-opioid drugs alleviate opioid withdrawal symptoms and are therefore consumed by opioid addicts. We asked 89 opioid-dependent patients participating in an out-patient opioid maintenance program to estimate the potential of several non-opioid drugs in being able to alleviate opioid withdrawal. We applied a five-point Lickert scale (1 = very good reduction of opioid withdrawal; 5 = no reduction of opioid withdrawal). Patients could also indicate a worsening of opioid withdrawal. Values (mean +/- SD) were: for benzodiazepines, 3.2 +/- 1.1; tricyclic antidepressants, 3.6 +/- 1.1; cannabis, 3.6 +/- 1.0; alcohol, 4.1 +/- 1.1; cocaine, 4.2 +/- 1.1; amphetamine, 4.4 +/- 0.9; nicotine, 4.7 +/- 0.7; and caffeine, 4.9 +/- 0.5. A worsening of opioid withdrawal was reported by 62% of the patients for cocaine, 62% for amphetamine, 50% for caffeine, 37.5% for cannabis, 27% for nicotine, 26% for alcohol, 8% for tricyclic antidepressants and 3% for benzodiazepines. Our study shows a low efficacy of non-opioid drugs in alleviating opioid withdrawal symptoms. The data basis of this study was good and the sample was suitable to be asked for estimations of drug-drug interactions. Of the patients, 26 - 62% even reported a worsening of opioid withdrawal for cannabis, alcohol, cocaine and amphetamine. Only benzodiazepines and tricyclic antidepressants were reported to have a moderate positive effect on opioid withdrawal.

Synthesis of [3]DIPPA: a potent irreversible antagonist selective for the κ opioid receptor

International Nuclear Information System (INIS)

Chang, Anchih; Portoghese, P.S.

1995-01-01

2-(3,4-Dichlorophenyl)-N-methyl-N-[(1S)-1-(3-isothiocyanatophe nyl)-2-(1-pyrrolidinyl)ethyl]acetamide (1,DIPPA) has been previously reported to be an opioid receptor affinity label that produces selective and long-lasting κ opioid receptor antagonism in mice. High specific activity [ 3 H]DIPPA (39.7 Ci/mmol) was prepared by bromination and catalytic tritiation of the amino precursor of DIPPA followed by conversion to the isothiocyanate with thiophosgene. (Author)

Opioid rotation with extended-release opioids: where should we begin?

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Nalamachu S

2011-12-01

Full Text Available Srinivas NalamachuInternational Clinical Research Institute and Pain Management Institute, Overland Park, KS, USAAbstract: Opioid rotation is a common and necessary clinical practice in the management of chronic non-cancer pain to improve therapeutic efficacy with the lowest opioid dose. When dose escalations fail to achieve adequate analgesia or are associated with intolerable side effects, a trial of a new opioid should be considered. Much of the scientific rationale of opioid rotation is based on the wide interindividual variability in sensitivity to opioid analgesics and the novel patient response observed when introducing an opioid-tolerant patient to a new opioid. This article discusses patient indicators for opioid rotation, the conversion process between opioid medications, and additional practical considerations for increasing the effectiveness of opioid therapy during a trial of a new opioid. A Patient vignette that demonstrates a step-wise approach to opioid rotation is also presented.Keywords: extended-release opioids, chronic pain, opioid rotation

Non-analgesic effects of opioids: opioids and the endocrine system.

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Elliott, Jennifer A; Opper, Susan E; Agarwal, Sonali; Fibuch, Eugene E

2012-01-01

Opioids are among the oldest known and most widely used analgesics. The application of opioids has expanded over the last few decades, especially in the treatment of chronic non-malignant pain. This upsurge in opioid use has been accompanied by the increasingly recognized occurrence of opioid-associated endocrinopathy. This may arise after exposure to enteral, parenteral, or neuraxial opioids. Opioid-associated endocrinopathy consists primarily of hypothalamic-pituitary-gonadal axis or hypothalamic-pituitary-adrenal axis dysfunction and may manifest with symptoms of hypogonadism, adrenal dysfunction, and other hormonal disturbances. Additionally, opioid related endocrine dysfunction may be coupled with such disorders as osteoporosis and mood disturbances including depression. Undesirable changes in pain sensitivity such as opioid-induced hyperalgesia, and reduced potency of opioid analgesia may also be potential consequences of chronic opioid consumption. Few studies to date have been able to establish what degree of opioid exposure, in terms of dose or duration of therapy, may predispose patients to opioid-associated endocrinopathy. This article will review the currently available literature concerning opioid-associated endocrinopathy and will provide recommendations for the evaluation, monitoring, and management of opioid-associated endocrinopathy and its other accompanying undesired effects.

Interacting cannabinoid and opioid receptors in the nucleus accumbens core control adolescent social play

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Antonia Manduca

2016-11-01

Full Text Available Social play behavior is a highly rewarding, developmentally important form of social interaction in young mammals. However, its neurobiological underpinnings remain incompletely understood. Previous work has suggested that opioid and endocannabinoid neurotransmission interact in the modulation of social play. Therefore, we combined behavioral, pharmacological, electrophysiological and genetic approaches to elucidate the role of the endocannabinoid 2-arachidonoylglycerol (2-AG in social play, and how cannabinoid and opioid neurotransmission interact to control social behavior in adolescent rodents. Systemic administration of the 2-AG hydrolysis inhibitor JZL184 or the opioid receptor agonist morphine increased social play behavior in adolescent rats. These effects were blocked by systemic pretreatment with either CB1 cannabinoid receptor (CB1R or mu-opioid receptor (MOR antagonists. The social play-enhancing effects of systemic morphine or JZL184 treatment were also prevented by direct infusion of the CB1R antagonist SR141716 and the MOR antagonist naloxone into the nucleus accumbens core (NAcC. Searching for synaptic correlates of these effects in adolescent NAcC excitatory synapses, we observed that CB1R antagonism blocked the effect of the MOR agonist DAMGO and, conversely, that naloxone reduced the effect of a cannabinoid agonist. These results were recapitulated in mice, and completely abolished in CB1R and MOR knockout mice, suggesting that the functional interaction between CB1R and MOR in the NAcC in the modulation of mediates social behavior is widespread in rodents. The data shed new light on the mechanism by which endocannabinoid lipids and opioid peptides interact to orchestrate rodent socioemotional behaviors.

Are Prescription Opioids Driving the Opioid Crisis? Assumptions vs Facts.

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Rose, Mark Edmund

2018-04-01

Sharp increases in opioid prescriptions, and associated increases in overdose deaths in the 2000s, evoked widespread calls to change perceptions of opioid analgesics. Medical literature discussions of opioid analgesics began emphasizing patient and public health hazards. Repetitive exposure to this information may influence physician assumptions. While highly consequential to patients with pain whose function and quality of life may benefit from opioid analgesics, current assumptions about prescription opioid analgesics, including their role in the ongoing opioid overdose epidemic, have not been scrutinized. Information was obtained by searching PubMed, governmental agency websites, and conference proceedings. Opioid analgesic prescribing and associated overdose deaths both peaked around 2011 and are in long-term decline; the sharp overdose increase recorded in 2014 was driven by illicit fentanyl and heroin. Nonmethadone prescription opioid analgesic deaths, in the absence of co-ingested benzodiazepines, alcohol, or other central nervous system/respiratory depressants, are infrequent. Within five years of initial prescription opioid misuse, 3.6% initiate heroin use. The United States consumes 80% of the world opioid supply, but opioid access is nonexistent for 80% and severely restricted for 4.1% of the global population. Many current assumptions about opioid analgesics are ill-founded. Illicit fentanyl and heroin, not opioid prescribing, now fuel the current opioid overdose epidemic. National discussion has often neglected the potentially devastating effects of uncontrolled chronic pain. Opioid analgesic prescribing and related overdoses are in decline, at great cost to patients with pain who have benefited or may benefit from, but cannot access, opioid analgesic therapy.

Population activity structure of excitatory and inhibitory neurons.

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Bittner, Sean R; Williamson, Ryan C; Snyder, Adam C; Litwin-Kumar, Ashok; Doiron, Brent; Chase, Steven M; Smith, Matthew A; Yu, Byron M

2017-01-01

Many studies use population analysis approaches, such as dimensionality reduction, to characterize the activity of large groups of neurons. To date, these methods have treated each neuron equally, without taking into account whether neurons are excitatory or inhibitory. We studied population activity structure as a function of neuron type by applying factor analysis to spontaneous activity from spiking networks with balanced excitation and inhibition. Throughout the study, we characterized population activity structure by measuring its dimensionality and the percentage of overall activity variance that is shared among neurons. First, by sampling only excitatory or only inhibitory neurons, we found that the activity structures of these two populations in balanced networks are measurably different. We also found that the population activity structure is dependent on the ratio of excitatory to inhibitory neurons sampled. Finally we classified neurons from extracellular recordings in the primary visual cortex of anesthetized macaques as putative excitatory or inhibitory using waveform classification, and found similarities with the neuron type-specific population activity structure of a balanced network with excitatory clustering. These results imply that knowledge of neuron type is important, and allows for stronger statistical tests, when interpreting population activity structure.

Population activity structure of excitatory and inhibitory neurons.

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Sean R Bittner

Full Text Available Many studies use population analysis approaches, such as dimensionality reduction, to characterize the activity of large groups of neurons. To date, these methods have treated each neuron equally, without taking into account whether neurons are excitatory or inhibitory. We studied population activity structure as a function of neuron type by applying factor analysis to spontaneous activity from spiking networks with balanced excitation and inhibition. Throughout the study, we characterized population activity structure by measuring its dimensionality and the percentage of overall activity variance that is shared among neurons. First, by sampling only excitatory or only inhibitory neurons, we found that the activity structures of these two populations in balanced networks are measurably different. We also found that the population activity structure is dependent on the ratio of excitatory to inhibitory neurons sampled. Finally we classified neurons from extracellular recordings in the primary visual cortex of anesthetized macaques as putative excitatory or inhibitory using waveform classification, and found similarities with the neuron type-specific population activity structure of a balanced network with excitatory clustering. These results imply that knowledge of neuron type is important, and allows for stronger statistical tests, when interpreting population activity structure.

Population activity structure of excitatory and inhibitory neurons

Science.gov (United States)

Doiron, Brent

2017-01-01

Many studies use population analysis approaches, such as dimensionality reduction, to characterize the activity of large groups of neurons. To date, these methods have treated each neuron equally, without taking into account whether neurons are excitatory or inhibitory. We studied population activity structure as a function of neuron type by applying factor analysis to spontaneous activity from spiking networks with balanced excitation and inhibition. Throughout the study, we characterized population activity structure by measuring its dimensionality and the percentage of overall activity variance that is shared among neurons. First, by sampling only excitatory or only inhibitory neurons, we found that the activity structures of these two populations in balanced networks are measurably different. We also found that the population activity structure is dependent on the ratio of excitatory to inhibitory neurons sampled. Finally we classified neurons from extracellular recordings in the primary visual cortex of anesthetized macaques as putative excitatory or inhibitory using waveform classification, and found similarities with the neuron type-specific population activity structure of a balanced network with excitatory clustering. These results imply that knowledge of neuron type is important, and allows for stronger statistical tests, when interpreting population activity structure. PMID:28817581

Pain, opioids, and sleep: implications for restless legs syndrome treatment.

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Trenkwalder, Claudia; Zieglgänsberger, Walter; Ahmedzai, Sam H; Högl, Birgit

2017-03-01

Opioid receptor agonists are known to relieve restless legs syndrome (RLS) symptoms, including both sensory and motor events, as well as improving sleep. The mechanisms of action of opioids in RLS are still a matter of speculation. The mechanisms by which endogenous opioids contribute to the pathophysiology of this polygenetic disorder, in which there are a number of variants, including developmental factors, remains unknown. A summary of the cellular mode of action of morphine and its (partial) antagonist naloxone via α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptors and the involvement of dendritic spine activation is described. By targeting pain and its consequences, opioids are the first-line treatment in many diseases and conditions with both acute and chronic pain and have thus been used in both acute and chronic pain conditions over the last 40 years. Addiction, dependence, and tolerability of opioids show a wide variability interindividually, as the response to opioids is influenced by a complex combination of genetic, molecular, and phenotypic factors. Although several trials have now addressed opioid treatment in RLS, hyperalgesia as a complication of long-term opioid treatment, or opioid-opioid interaction have not received much attention so far. Therapeutic opioids may act not only on opioid receptors but also via histamine or N-methyl-d-aspartate (NMDA) receptors. In patients with RLS, one of the few studies investigating opioid bindings found that possible brain regions involved in the severity of RLS symptoms are similar to those known to be involved in chronic pain, such as the medial pain system (medial thalamus, amygdala, caudate nucleus, anterior cingulate gyrus, insular cortex, and orbitofrontal cortex). The results of this diprenorphine positron emission tomography study suggested that the more severe the RLS, the greater the release of endogenous opioids. Since 1993, when the first small controlled study was performed with

Effects of Ketamine on Neuronal Spontaneous Excitatory Postsynaptic Currents and Miniature Excitatory Postsynaptic Currents in the Somatosensory Cortex of Rats

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Chengdong Yuan

2016-07-01

Full Text Available Background: Ketamine is a commonly used intravenous anesthetic which produces dissociation anesthesia, analgesia, and amnesia. The mechanism of ketamine-induced synaptic inhibition in high-level cortical areas is still unknown. We aimed to elucidate the effects of different concentrations of ketamine on the glutamatergic synaptic transmission of the neurons in the primary somatosensory cortex by using the whole-cell patch-clamp method. Methods: Sprague-Dawley rats (11–19 postnatal days, n=36 were used to obtain brain slices (300 μM. Spontaneous excitatory postsynaptic currents (data from 40 neurons were recorded at a command potential of -70 mV in the presence of bicuculline (a competitive antagonist of GABAA receptors, 30 μM and strychnine (glycine receptor antagonist, 30 μM. Miniature excitatory postsynaptic currents (data from 40 neurons were also recorded when 1 μM of tetrodotoxin was added into the artificial cerebrospinal fluid. We used GraphPad Prism5for statistical analysis. Significant differences in the mean amplitude and frequency were tested using the Student paired 2-tailed t test. Values of P<0.05 were considered significant. Results: Different concentrations of ketamine inhibited the frequency and amplitude of the spontaneous excitatory postsynaptic currents as well as the amplitude of the miniature excitatory postsynaptic currents in a concentration-dependent manner, but they exerted no significant effect on the frequency of the miniature excitatory postsynaptic currents. Conclusion: Ketamine inhibited the excitatory synaptic transmission of the neurons in the primary somatosensory cortex. The inhibition may have been mediated by a reduction in the sensitivity of the postsynaptic glutamatergic receptors.

Are peripheral opioid antagonists the solution to opioid side effects?

LENUS (Irish Health Repository)

Bates, John J

2012-02-03

Opioid medication is the mainstay of therapy for severe acute and chronic pain. Unfortunately, the side effects of these medications can affect patient comfort and safety, thus limiting their proven therapeutic potential. Whereas the main analgesic effects of opioids are centrally mediated, many of the common side effects are mediated via peripheral receptors. Novel peripheral opioid antagonists have been recently introduced that can block the peripheral actions of opioids without affecting centrally mediated analgesia. We review the clinical and experimental evidence of their efficacy in ameliorating opioid side effects and consider what further information might be useful in defining their role. IMPLICATIONS: The major analgesic effects of opioid medication are mediated within the brain and spinal cord. Many of the side effects of opioids are caused by activation of receptors outside these areas. Recently developed peripherally restricted opioid antagonists have the ability to block many opioid side effects without affecting analgesia.

Opioid intoxication

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... easily result in intoxication. The provider prescribes a sleep medicine (sedative) in addition to the opioid. The provider ... an opioid with certain other drugs, such as sleep medicines or alcohol Taking the opioid in ways not ...

Opiate-induced suppression of rat hypoglossal motoneuron activity and its reversal by ampakine therapy.

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Amanda R Lorier

2010-01-01

Full Text Available Hypoglossal (XII motoneurons innervate tongue muscles and are vital for maintaining upper-airway patency during inspiration. Depression of XII nerve activity by opioid analgesics is a significant clinical problem, but underlying mechanisms are poorly understood. Currently there are no suitable pharmacological approaches to counter opiate-induced suppression of XII nerve activity while maintaining analgesia. Ampakines accentuate alpha-amino-3-hydroxyl-5-methyl-4-isoxazole-propionate (AMPA receptor responses. The AMPA family of glutamate receptors mediate excitatory transmission to XII motoneurons. Therefore the objectives were to determine whether the depressant actions of mu-opioid receptor activation on inspiratory activity includes a direct inhibitory action at the inspiratory premotoneuron to XII motoneuron synapse, and to identify underlying mechanism(s. We then examined whether ampakines counteract opioid-induced depression of XII motoneuron activity.A medullary slice preparation from neonatal rat that produces inspiratory-related output in vitro was used. Measurements of inspiratory burst amplitude and frequency were made from XII nerve roots. Whole-cell patch recordings from XII motoneurons were used to measure membrane currents and synaptic events. Application of the mu-opioid receptor agonist, DAMGO, to the XII nucleus depressed the output of inspiratory XII motoneurons via presynaptic inhibition of excitatory glutamatergic transmission. Ampakines (CX614 and CX717 alleviated DAMGO-induced depression of XII MN activity through postsynaptic actions on XII motoneurons.The inspiratory-depressant actions of opioid analgesics include presynaptic inhibition of XII motoneuron output. Ampakines counteract mu-opioid receptor-mediated depression of XII motoneuron inspiratory activity. These results suggest that ampakines may be beneficial in countering opiate-induced suppression of XII motoneuron activity and resultant impairment of airway patency.

The role of opioid antagonist efficacy and constitutive opioid receptor activity in the opioid withdrawal syndrome in mice

OpenAIRE

Navani, Dipesh M.; Sirohi, Sunil; Madia, Priyanka A.; Yoburn, Byron C.

2011-01-01

On the basis of efficacy, opioid antagonists are classified as inverse opioid agonists (e.g. naltrexone) or neutral opioid antagonists (e.g. 6β-naltrexol). This study examined the interaction between naltrexone and 6β-naltrexol in the precipitated opioid withdrawal syndrome in morphine dependent mice. Furthermore, the possible contribution of constitutive opioid receptor activity to precipitated withdrawal was evaluated using increasing levels of morphine dependence. In the first experiment, ...

Radioreceptor opioid assay

International Nuclear Information System (INIS)

Miller, R.J.; Chang, K.-J.

1981-01-01

A radioreceptor assay is described for assaying opioid drugs in biological fluids. The method enables the assay of total opioid activity, being specific for opioids as a class but lacking specificity within the class. A radio-iodinated opioid and the liquid test sample are incubated with an opiate receptor material. The percentage inhibition of the binding of the radio-iodinated compound to the opiate receptor is calculated and the opioid activity of the test liquid determined from a standard curve. Examples of preparing radio-iodinated opioids and assaying opioid activity are given. A test kit for the assay is described. Compared to other methods, this assay is cheap, easy and rapid. (U.K.)

Stereochemical Basis for a Unified Structure Activity Theory of Aromatic and Heterocyclic Rings in Selected Opioids and Opioid Peptides

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Joel S. Goldberg

2010-02-01

Full Text Available This paper presents a novel unified theory of the structure activity relationship of opioids and opioid peptides. It is hypothesized that a virtual or known heterocyclic ring exists in all opioids which have activity in humans, and this ring occupies relative to the aromatic ring of the drug, approximately the same plane in space as the piperidine ring of morphine. Since the rings of morphine are rigid, and the aromatic and piperidine rings are critical structural components for morphine’s analgesic properties, the rigid morphine molecule allows for approximations of the aromatic and heterocyclic relationships in subsequent drug models where bond rotations are common. This hypothesis and five propositions are supported by stereochemistry and experimental observations. Proposition #1 The structure of morphine provides a template. Proposition #2 Steric hindrance of some centric portion of the piperidine ring explains antagonist properties of naloxone, naltrexone and alvimopam. Proposition #3 Methadone has an active conformation which contains a virtual heterocyclic ring which explains its analgesic activity and racemic properties. Proposition #4 The piperidine ring of fentanyl can assume the morphine position under conditions of nitrogen inversion. Proposition #5 The first 3 amino acid sequences of beta endorphin (l-try-gly-gly and the active opioid dipeptide, l-tyr-pro, (as a result of a peptide turn and zwitterion bonding form a virtual piperazine-like ring which is similar in size, shape and location to the heterocyclic rings of morphine, meperidine, and methadone. Potential flaws in this theory are discussed. This theory could be important for future analgesic drug design.

Using behavioral economics to predict opioid use during prescription opioid dependence treatment.

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Worley, Matthew J; Shoptaw, Steven J; Bickel, Warren K; Ling, Walter

2015-03-01

Research grounded in behavioral economics has previously linked addictive behavior to disrupted decision-making and reward-processing, but these principles have not been examined in prescription opioid addiction, which is currently a major public health problem. This study examined whether pre-treatment drug reinforcement value predicted opioid use during outpatient treatment of prescription opioid addiction. Secondary analyses examined participants with prescription opioid dependence who received 12 weeks of buprenorphine-naloxone and counseling in a multi-site clinical trial (N=353). Baseline measures assessed opioid source and indices of drug reinforcement value, including the total amount and proportion of income spent on drugs. Weekly urine drug screens measured opioid use. Obtaining opioids from doctors was associated with lower pre-treatment drug spending, while obtaining opioids from dealers/patients was associated with greater spending. Controlling for demographics, opioid use history, and opioid source frequency, patients who spent a greater total amount (OR=1.30, peconomic resources to drugs, reflects propensity for continued opioid use during treatment among individuals with prescription opioid addiction. Future studies should examine disrupted decision-making and reward-processing in prescription opioid users more directly and test whether reinforcer pathology can be remediated in this population. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

Irregular persistent activity induced by synaptic excitatory feedback

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Francesca Barbieri

2007-11-01

Full Text Available Neurophysiological experiments on monkeys have reported highly irregular persistent activity during the performance of an oculomotor delayed-response task. These experiments show that during the delay period the coefficient of variation (CV of interspike intervals (ISI of prefrontal neurons is above 1, on average, and larger than during the fixation period. In the present paper, we show that this feature can be reproduced in a network in which persistent activity is induced by excitatory feedback, provided that (i the post-spike reset is close enough to threshold , (ii synaptic efficacies are a non-linear function of the pre-synaptic firing rate. Non-linearity between presynaptic rate and effective synaptic strength is implemented by a standard short-term depression mechanism (STD. First, we consider the simplest possible network with excitatory feedback: a fully connected homogeneous network of excitatory leaky integrate-and-fire neurons, using both numerical simulations and analytical techniques. The results are then confirmed in a network with selective excitatory neurons and inhibition. In both the cases there is a large range of values of the synaptic efficacies for which the statistics of firing of single cells is similar to experimental data.

Opioid antagonists with minimal sedation for opioid withdrawal.

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Gowing, Linda; Ali, Robert; White, Jason M

2017-05-29

Managed withdrawal is a necessary step prior to drug-free treatment or as the endpoint of long-term substitution treatment. To assess the effects of opioid antagonists plus minimal sedation for opioid withdrawal. Comparators were placebo as well as more established approaches to detoxification, such as tapered doses of methadone, adrenergic agonists, buprenorphine and symptomatic medications. We updated our searches of the following databases to December 2016: CENTRAL, MEDLINE, Embase, PsycINFO and Web of Science. We also searched two trials registers and checked the reference lists of included studies for further references to relevant studies. We included randomised and quasi-randomised controlled clinical trials along with prospective controlled cohort studies comparing opioid antagonists plus minimal sedation versus other approaches or different opioid antagonist regimens for withdrawal in opioid-dependent participants. We used standard methodological procedures expected by Cochrane. Ten studies (6 randomised controlled trials and 4 prospective cohort studies, involving 955 participants) met the inclusion criteria for the review. We considered 7 of the 10 studies to be at high risk of bias in at least one of the domains we assessed.Nine studies compared an opioid antagonist-adrenergic agonist combination versus a treatment regimen based primarily on an alpha 2 -adrenergic agonist (clonidine or lofexidine). Other comparisons (placebo, tapered doses of methadone, buprenorphine) made by included studies were too diverse for any meaningful analysis. This review therefore focuses on the nine studies comparing an opioid antagonist (naltrexone or naloxone) plus clonidine or lofexidine versus treatment primarily based on clonidine or lofexidine.Five studies took place in an inpatient setting, two studies were in outpatients with day care, two used day care only for the first day of opioid antagonist administration, and one study described the setting as outpatient

Mu Opioid Receptor Gene: New Point Mutations in Opioid Addicts

Directory of Open Access Journals (Sweden)

Amin Dinarvand

2014-02-01

Full Text Available Introduction: Association between single-nucleotide polymorphisms (SNPs in mu opioid receptor gene and drug addiction has been shown in various studies. Here, we have evaluated the existence of polymorphisms in exon 3 of this gene in Iranian population and investigated the possible association between these mutations and opioid addiction.  Methods: 79 opioid-dependent subjects (55 males, 24 females and 134 non-addict or control individuals (74 males, 60 females participated in the study. Genomic DNA was extracted from volunteers’ peripheral blood and exon 3 of the mu opioid receptor gene was amplified by polymerase chain reaction (PCR whose products were then sequenced.  Results: Three different heterozygote polymorphisms were observed in 3 male individuals: 759T>C and 877G>A mutations were found in 2 control volunteers and 1043G>C substitution was observed in an opioid-addicted subject. Association between genotype and opioid addiction for each mutation was not statistically significant.  Discussion: It seems that the sample size used in our study is not enough to confirm or reject any association between 759T>C, 877G>A and 1043G>C substitutions in exon 3 of the mu opioid receptor gene and opioid addiction susceptibility in Iranian population.

Chimeric opioid peptides: Tools for identifying opioid receptor types

International Nuclear Information System (INIS)

Xie, G.; Miyajima, A.; Yokota, T.; Arai, K.; Goldstein, A.

1990-01-01

The authors synthesized several chimeric [125J-labelled] peptides in which the N-terminal nine residues of dynorphin-32, a peptide selective for the κ opioid receptor, were replaced by opioid peptides selective for other opioid receptor types. Each chimeric peptide retained the high affinity and type selectivity characteristic of its N-terminal sequence. The common C-terminal two-thirds of the chimeric peptides served as an epitope recognized by the same monoclonal antibody. When bound to receptors on a cell surface or membrane preparation, these peptides could still bind specifically to the monoclonal antibody. These chimeric peptides should be useful for isolating μ, δ, and κ opioid receptors and for identifying opioid receptors on transfected cells in expression cloning procedures. The general approach using chimeric peptides should be applicable to other peptide receptors

LRRTM3 Regulates Excitatory Synapse Development through Alternative Splicing and Neurexin Binding

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Ji Won Um

2016-02-01

Full Text Available The four members of the LRRTM family (LRRTM1-4 are postsynaptic adhesion molecules essential for excitatory synapse development. They have also been implicated in neuropsychiatric diseases. Here, we focus on LRRTM3, showing that two distinct LRRTM3 variants generated by alternative splicing regulate LRRTM3 interaction with PSD-95, but not its excitatory synapse-promoting activity. Overexpression of either LRRTM3 variant increased excitatory synapse density in dentate gyrus (DG granule neurons, whereas LRRTM3 knockdown decreased it. LRRTM3 also controlled activity-regulated AMPA receptor surface expression in an alternative splicing-dependent manner. Furthermore, Lrrtm3-knockout mice displayed specific alterations in excitatory synapse density, excitatory synaptic transmission and excitability in DG granule neurons but not in CA1 pyramidal neurons. Lastly, LRRTM3 required only specific splice variants of presynaptic neurexins for their synaptogenic activity. Collectively, our data highlight alternative splicing and differential presynaptic ligand utilization in the regulation of LRRTMs, revealing key regulatory mechanisms for excitatory synapse development.

High-Dose Opioid Prescribing and Opioid-Related Hospitalization: A Population-Based Study.

Directory of Open Access Journals (Sweden)

Kimberly Fernandes

Full Text Available To examine the impact of national clinical practice guidelines and provincial drug policy interventions on prevalence of high-dose opioid prescribing and rates of hospitalization for opioid toxicity.Interventional time-series analysis.Ontario, Canada, from 2003 to 2014.Ontario Drug Benefit (ODB beneficiaries aged 15 to 64 years from 2003 to 2014.Publication of Canadian clinical practice guidelines for use of opioids in chronic non-cancer pain (May 2010 and implementation of Ontario's Narcotics Safety and Awareness Act (NSAA; November 2011.Three outcomes were explored: the rate of opioid use among ODB beneficiaries, the prevalence of opioid prescriptions exceeding 200 mg and 400 mg morphine equivalents per day, and rates of opioid-related emergency department visits and hospital admissions.Over the 12 year study period, the rate of opioid use declined 15.2%, from 2764 to 2342 users per 10,000 ODB eligible persons. The rate of opioid use was significantly impacted by the Canadian clinical practice guidelines (p-value = .03 which led to a decline in use, but no impact was observed by the enactment of the NSAA (p-value = .43. Among opioid users, the prevalence of high-dose prescribing doubled (from 4.2% to 8.7% over the study period. By 2014, 40.9% of recipients of long-acting opioids exceeded daily doses of 200 mg morphine or equivalent, including 55.8% of long-acting oxycodone users and 76.3% of transdermal fentanyl users. Moreover, in the last period, 18.7% of long-acting opioid users exceeded daily doses of 400 mg morphine or equivalent. Rates of opioid-related emergency department visits and hospital admissions increased 55.0% over the study period from 9.0 to 14.0 per 10,000 ODB beneficiaries from 2003 to 2013. This rate was not significantly impacted by the Canadian clinical practice guidelines (p-value = .68 or enactment of the NSAA (p-value = .59.Although the Canadian clinical practice guidelines for use of opioids in chronic non

Opioid tapering in patients with prescription opioid use disorder : A retrospective study

NARCIS (Netherlands)

Zhou, Kehua; Jia, Peng; Bhargava, Swati; Zhang, Yong; Reza, Taslima; Peng, Yuan Bo; Wang, Gary G.

2017-01-01

Background and aims: Opioid use disorder (OUD) refers to a maladaptive pattern of opioid use leading to clinically significant impairment or distress. OUD causes, and vice versa, misuses and abuse of opioid medications. Clinicians face daily challenges to treat patients with prescription opioid use

Past-year Prescription Drug Monitoring Program Opioid Prescriptions and Self-reported Opioid Use in an Emergency Department Population With Opioid Use Disorder.

Science.gov (United States)

Hawk, Kathryn; D'Onofrio, Gail; Fiellin, David A; Chawarski, Marek C; O'Connor, Patrick G; Owens, Patricia H; Pantalon, Michael V; Bernstein, Steven L

2017-11-22

Despite increasing reliance on prescription drug monitoring programs (PDMPs) as a response to the opioid epidemic, the relationship between aberrant drug-related behaviors captured by the PDMP and opioid use disorder is incompletely understood. How PDMP data should guide emergency department (ED) assessment has not been studied. The objective was to evaluate a relationship between PDMP opioid prescription records and self-reported nonmedical opioid use of prescription opioids in a cohort of opioid-dependent ED patients enrolled in a treatment trial. PDMP opioid prescription records during 1 year prior to study enrollment on 329 adults meeting Diagnostic and Statistical Manual IV criteria for opioid dependence entering a randomized clinical trial in a large, urban ED were cross-tabulated with data on 30-day nonmedical prescription opioid use self-report. The association among these two types of data was assessed by the Goodman and Kruskal's gamma; a logistic regression was used to explore characteristics of participants who had PDMP record of opioid prescriptions. During 1 year prior to study enrollment, 118 of 329 (36%) patients had at least one opioid prescription (range = 1-51) in our states' PDMP. Patients who reported ≥15 of 30 days of nonmedical prescription opioid use were more likely to have at least four PDMP opioid prescriptions (20/38; 53%) than patients reporting 1 to 14 days (14/38, 37%) or zero days of nonmedical prescription opioid use (4/38, 11%; p = 0.002). Female sex and having health insurance were significantly more represented in the PDMP (p Medicine.

Role and psychological dependenci arrangement of opioid by type of reseptor opioid

OpenAIRE

Arif Nurrochmad, Arif Nurrochmad

2015-01-01

Opioid receptor can be classified as p., 8, and K-opioid receptor that widely expressed in the CNS. The development of selective receptor agonist and cloning of each receptor have contributed greatly to our increasing knowledge of the neuropharmacological profile of each opioid receptor type. This review focuses on the functional interaction among these opioid receptor types that contribute to opioid dependence especially in psychological dependence. Several lines of evidence provide argument...

Internalisation of the mu-opioid receptor by endomorphin-1 and leu-enkephalin is dependant on aromatic amino acid residues.

Science.gov (United States)

Del Borgo, Mark P; Blanchfield, Joanne T; Toth, Istvan

2008-04-15

The opioid receptor system in the central nervous system controls a number of physiological processes, most notably pain. However, most opioids currently available have a variety of side-effects as well as exhibiting tolerance. Tolerance is most likely to be a complex phenomenon, however, the role of receptor internalisation is thought to play a crucial role. In this study, we examined the role of aromaticity in ligand-mediated receptor internalisation of the mu-opioid receptor (MOPR). These studies show that the amount of receptor internalisation may be dependant on the amphiphilicity of the ligand. Specifically, deletion of the C-terminus aromatic residues of endomorphin 1, particularly tryptophan reduces receptor-mediated internalisation whilst the addition of tryptophan within the enkephalin sequence increases receptor internalisation and decreases tolerance.

Co-morbid pain and opioid addiction: long term effect of opioid maintenance on acute pain.

Science.gov (United States)

Wachholtz, Amy; Gonzalez, Gerardo

2014-12-01

Medication assisted treatment for opioid dependence alters the pain experience. This study will evaluate changes pain sensitivity and tolerance with opioid treatments; and duration of this effect after treatment cessation. 120 Individuals with chronic pain were recruited in 4 groups (N = 30): 1-methadone for opioid addiction; 2-buprenorphine for opioid addiction; 3-history of opioid maintenance treatment for opioid addiction but with prolonged abstinence (M = 121 weeks; SD = 23.3); and 4-opioid naïve controls. Participants completed a psychological assessment and a cold water task including, time to first pain (sensitivity) and time to stopping the pain task (tolerance). Data analysis used survival analyses. A Kaplan-Meier-Cox survival analysis showed group differences for both pain sensitivity (log rank = 15.50; p opioid maintenance resulted in differing pain sensitivity compared to opioid naïve (p's opioid maintenance compared to active methadone patients (p opioid naïve control group participants (p's opioid abstinence increased (R = .37; p opioid maintenance, there appears to be long-term differences in pain sensitivity that do not resolve with discontinuation of opioid maintenance. Although pain sensitivity does not change, pain tolerance does improve after opioid maintenance cessation. Implications for treating co-morbid opioid addiction and pain (acute and chronic) are discussed. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

Distance traveled and frequency of interstate opioid dispensing in opioid shoppers and nonshoppers.

Science.gov (United States)

Cepeda, M Soledad; Fife, Daniel; Yuan, Yingli; Mastrogiovanni, Greg

2013-10-01

Little is known about how far opioid shoppers travel or how often they cross state lines to fill their opioid prescriptions. This retrospective cohort study evaluated these measures for opioid shoppers and nonshoppers using a large U.S. prescription database. Patients with ≥3 opioid dispensings were followed for 18 months. A subject was considered a shopper when he or she filled overlapping opioid prescriptions written by >1 prescriber at ≥3 pharmacies. A heavy shopper had ≥5 shopping episodes. Outcomes assessed were distance traveled among pharmacies and number of states visited to fill opioid prescriptions. A total of 10,910,451 subjects were included; .7% developed any shopping behavior and their prescriptions accounted for 8.6% of all opioid dispensings. Shoppers and heavy shoppers were younger than the nonshoppers. Shoppers traveled a median of 83.8 miles, heavy shoppers 199.5 miles, and nonshoppers 0 miles. Almost 20% of shoppers or heavy shoppers, but only 4% of nonshoppers, visited >1 state. Shoppers traveled greater distances and more often crossed state borders to fill opioid prescriptions than nonshoppers, and their dispensings accounted for a disproportionate number of opioid dispensings. Sharing of data among prescription-monitoring programs will likely strengthen those programs and may decrease shopping behavior. This study shows that opioid shoppers travel greater distances and more often cross state borders to fill opioid prescriptions than nonshoppers, and their dispensings accounted for a disproportionate number of opioid dispensings. The findings support the need for data sharing among prescription-monitoring programs to deter opioid shopping behavior. Copyright © 2013 American Pain Society. Published by Elsevier Inc. All rights reserved.

Nonopioid substance use disorders and opioid dose predict therapeutic opioid addiction.

Science.gov (United States)

Huffman, Kelly L; Shella, Elizabeth R; Sweis, Giries; Griffith, Sandra D; Scheman, Judith; Covington, Edward C

2015-02-01

Limited research examines the risk of therapeutic opioid addiction (TOA) in patients with chronic noncancer pain. This study examined TOA among 199 patients undergoing long-term opioid therapy at the time of admission to a pain rehabilitation program. It was hypothesized that nonopioid substance use disorders and opioid dosage would predict TOA. Daily mean opioid dose was 132.85 mg ± 175.39. Patients with nonopioid substance use disorders had 28 times the odds (odds ratio [OR] = 28.58; 95% confidence interval [CI] = 10.86, 75.27) of having TOA. Each 50-mg increase in opioid dose nearly doubled the odds of TOA (OR = 1.73; 95% CI = 1.29, 2.32). A 100-mg increase was associated with a 3-fold increase in odds (OR = 3.00; 95% CI = 1.67, 5.41). Receiver operating characteristic analysis revealed that opioid dose was a moderately accurate predictor (area under the curve = .75; 95% CI = .68, .82) of TOA. The sensitivity (.70) and specificity (.68) of opioid dose in predicting TOA was maximized at 76.10 mg; in addition, 46.00 mg yielded 80% sensitivity in identifying TOA. These results underscore the importance of obtaining a substance use history prior to prescribing and suggest a low screening threshold for TOA in patients who use opioids in the absence of improvement in pain or functional impairment. This article examines TOA in patients with chronic noncancer pain undergoing long-term opioid therapy. Results suggest that patients should be screened for nonopioid substance use disorders prior to prescribing. In the absence of improvement in pain or function, there is a low threshold (∼50 mg daily opioid dose) for addiction screening. Copyright © 2015 American Pain Society. Published by Elsevier Inc. All rights reserved.

Neonatal opioid withdrawal syndrome.

Science.gov (United States)

Sutter, Mary Beth; Leeman, Lawrence; Hsi, Andrew

2014-06-01

Neonatal opioid withdrawal syndrome is common due to the current opioid addiction epidemic. Infants born to women covertly abusing prescription opioids may not be identified as at risk until withdrawal signs present. Buprenorphine is a newer treatment for maternal opioid addiction and appears to result in a milder withdrawal syndrome than methadone. Initial treatment is with nonpharmacological measures including decreasing stimuli, however pharmacological treatment is commonly required. Opioid monotherapy is preferred, with phenobarbital or clonidine uncommonly needed as adjunctive therapy. Rooming-in and breastfeeding may decease the severity of withdrawal. Limited evidence is available regarding long-term effects of perinatal opioid exposure. Copyright © 2014 Elsevier Inc. All rights reserved.

Physician Introduction to Opioids for Pain Among Patients with Opioid Dependence and Depressive Symptoms

Science.gov (United States)

Tsui, Judith I.; Herman, Debra S.; Kettavong, Malyna; Alford, Daniel; Anderson, Bradley J.; Stein, Michael D.

2011-01-01

This study determined the frequency of reporting being introduced to opioids by a physician among opioid dependent patients. Cross-sectional analyses were performed using baseline data from a cohort of opioid addicts seeking treatment with buprenorphine. The primary outcome was response to the question: “Who introduced you to opiates?” Covariates included sociodemographics, depression, pain, current and prior substance use. Of 140 participants, 29% reported that they had been introduced to opioids by a physician. Of those who were introduced to opioids by a physician, all indicated that they had initially used opioids for pain, versus only 11% of those who did not report being introduced to opioids by a physician (p<0.01). There was no difference in current pain (78% vs. 85%, p=0.29), however participants who were introduced to opioids by a physician were more likely to have chronic pain (63% vs. 43%, p=0.04). A substantial proportion of individuals with opioid dependence seeking treatment may have been introduced to opioids by a physician. PMID:20727704

Medications Development for Opioid Abuse

Science.gov (United States)

Negus, S. Stevens; Banks, Matthew L.

2013-01-01

Here we describe methods for preclinical evaluation of candidate medications to treat opioid abuse and dependence. Our perspective is founded on the propositions that (1) drug self-administration procedures provide the most direct method for assessment of medication effects, (2) procedures that assess choice between opioid and nondrug reinforcers are especially useful, and (3) the states of opioid dependence and withdrawal profoundly influence both opioid reinforcement and the effects of candidate medications. Effects of opioid medications on opioid choice in nondependent and opioid-dependent subjects are reviewed. Various nonopioid medications have also been examined, but none yet have been identified that safely and reliably reduce opioid choice. Future research will focus on (1) strategies for increasing safety and/or effectiveness of opioid medications, and (2) continued development of nonopioids such as inhibitors of endocannabinoid catabolic enzymes or inhibitors of opioid-induced glial activation. PMID:23125072

Excitatory Neuronal Hubs Configure Multisensory Integration of Slow Waves in Association Cortex

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Satoshi Kuroki

2018-03-01

Full Text Available Summary: Multisensory integration (MSI is a fundamental emergent property of the mammalian brain. During MSI, perceptual information encoded in patterned activity is processed in multimodal association cortex. The systems-level neuronal dynamics that coordinate MSI, however, are unknown. Here, we demonstrate intrinsic hub-like network activity in the association cortex that regulates MSI. We engineered calcium reporter mouse lines based on the fluorescence resonance energy transfer sensor yellow cameleon (YC2.60 expressed in excitatory or inhibitory neurons. In medial and parietal association cortex, we observed spontaneous slow waves that self-organized into hubs defined by long-range excitatory and local inhibitory circuits. Unlike directional source/sink-like flows in sensory areas, medial/parietal excitatory and inhibitory hubs had net-zero balanced inputs. Remarkably, multisensory stimulation triggered rapid phase-locking mainly of excitatory hub activity persisting for seconds after the stimulus offset. Therefore, association cortex tends to form balanced excitatory networks that configure slow-wave phase-locking for MSI. Video Abstract: : Kuroki et al. performed cell-type-specific, wide-field FRET-based calcium imaging to visualize cortical network activity induced by multisensory inputs. They observed phase-locking of cortical slow waves in excitatory neuronal hubs in association cortical areas that may underlie multisensory integration. Keywords: wide-field calcium imaging, multisensory integration, cortical slow waves, association cortex, phase locking, fluorescence resonance energy transfer, spontaneous activity, excitatory neuron, inhibitory neuron, mouse

Opioid tapering in patients with prescription opioid use disorder: A retrospective study.

Science.gov (United States)

Zhou, Kehua; Jia, Peng; Bhargava, Swati; Zhang, Yong; Reza, Taslima; Peng, Yuan Bo; Wang, Gary G

2017-10-01

Opioid use disorder (OUD) refers to a maladaptive pattern of opioid use leading to clinically significant impairment or distress. OUD causes, and vice versa, misuses and abuse of opioid medications. Clinicians face daily challenges to treat patients with prescription opioid use disorder. An evidence-based management for people who are already addicted to opioids has been identified as the national priority in the US; however, options are limited in clinical practices. In this study, we aimed to explore the success rate and important adjuvant medications in the medication assisted treatment with temporary use of methadone for opioid discontinuation in patients with prescription OUD. This is a retrospective chart review performed at a private physician office for physical medicine and rehabilitation. We reviewed all medical records dated between December 1st, 2011 and August 30th, 2016. The initial evaluation of the included patients (N=140) was completed between December 1st, 2011 and December 31st, 2014. They all have concumittant prescription OUD and chronic non-cancer pain. The patients (87 female and 53 male) were 46.7±12.7 years old, and had a history of opioid use of 7.7±6.1 years. All patients received the comprehensive opioid taper treatments (including interventional pain management techniques, psychotherapy, acupuncture, physical modalities and exercises, and adjuvant medications) on top of the medication assisted treatment using methadone (transient use). Opioid tapering was considered successful when no opioid medication was used in the last patient visit. The 140 patients had pain of 9.6±8.4 years with 8/10 intensity before treatment which decreased after treatment in all comparisons (pOUD. For patients with OUD, indefinite opioid maintenance treatment may not be necessary. Considering the ethical values of autonomy, nonmaleficence, and beneficence, clinicians should provide patients with OUD the option of opioid tapering. Copyright © 2017

Chimeric opioid peptides: tools for identifying opioid receptor types.

OpenAIRE

Xie, G X; Miyajima, A; Yokota, T; Arai, K; Goldstein, A

1990-01-01

We synthesized several chimeric peptides in which the N-terminal nine residues of dynorphin-32, a peptide selective for the kappa opioid receptor, were replaced by opioid peptides selective for other opioid receptor types. Each chimeric peptide retained the high affinity and type selectivity characteristic of its N-terminal sequence. The common C-terminal two-thirds of the chimeric peptides served as an epitope recognized by the same monoclonal antibody. When bound to receptors on a cell surf...

Chemo-enzymatic synthesis of (2S,4R)-2-amino-4-(3-(2,2-diphenylethylamino)-3-oxopropyl)pentanedioic acid

DEFF Research Database (Denmark)

Sagot, Emanuelle; Jensen, Anders A.; Pickering, Darryl S

2008-01-01

In the mammalian central nervous system (CNS), the action of sodium dependent excitatory amino acid transporters (EAATs) is responsible for termination of glutamatergic neurotransmission by reuptake of ( S) -glutamate (Glu) from the synaptic cleft. Five EAAT subtypes have been identified, of which...

Opioid withdrawal suppression efficacy of oral dronabinol in opioid dependent humans.

Science.gov (United States)

Lofwall, Michelle R; Babalonis, Shanna; Nuzzo, Paul A; Elayi, Samy Claude; Walsh, Sharon L

2016-07-01

The cannabinoid (CB) system is a rational novel target for treating opioid dependence, a significant public health problem around the world. This proof-of-concept study examined the potential efficacy of a CB1 receptor partial agonist, dronabinol, in relieving signs and symptoms of opioid withdrawal. Twelve opioid dependent adults participated in this 5-week, inpatient, double-blind, randomized, placebo-controlled study. Volunteers were maintained on double-blind oxycodone (30mg oral, four times/day) and participated in a training session followed by 7 experimental sessions, each testing a single oral test dose (placebo, oxycodone 30 and 60mg, dronabinol 5, 10, 20, and 30mg [decreased from 40mg]). Placebo was substituted for oxycodone maintenance doses for 21h before each session in order to produce measurable opioid withdrawal. Outcomes included observer- and participant-ratings of opioid agonist, opioid withdrawal and psychomotor/cognitive performance. Oxycodone produced prototypic opioid agonist effects (i.e. suppressing withdrawal and increasing subjective effects indicative of abuse liability). Dronabinol 5 and 10mg produced effects most similar to placebo, while the 20 and 30mg doses produced modest signals of withdrawal suppression that were accompanied by dose-related increases in high, sedation, bad effects, feelings of heart racing, and tachycardia. Dronabinol was not liked more than placebo, showed some impairment in cognitive performance, and was identified as marijuana with increasing dose. CB1 receptor activation is a reasonable strategy to pursue for the treatment of opioid withdrawal; however, dronabinol is not a likely candidate given its modest withdrawal suppression effects of limited duration and previously reported tachycardia during opioid withdrawal. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Sex differences in opioid analgesia and addiction: interactions among opioid receptors and estrogen receptors

Science.gov (United States)

2013-01-01

Opioids are widely used as the pain reliever and also notorious for being addictive drugs. Sex differences in the opioid analgesia and addiction have been reported and investigated in human subjects and animal models. Yet, the molecular mechanism underlying the differences between males and females is still unclear. Here, we reviewed the literature describing the sex differences in analgesic responses and addiction liabilities to clinically relevant opioids. The reported interactions among opioids, estrogens, opioid receptors, and estrogen receptors are also evaluated. We postulate that the sex differences partly originated from the crosstalk among the estrogen and opioid receptors when stimulated by the exogenous opioids, possibly through common secondary messengers and the downstream gene transcriptional regulators. PMID:24010861

Craving and subsequent opioid use among opioid dependent patients who initiate treatment with buprenorphine

Science.gov (United States)

Tsui, Judith I.; Anderson, Bradley J.; Strong, David R.; Stein, Michael D.

2016-01-01

Background Few studies have directly assessed associations between craving and subsequent opioid use among treated patients. Our objective was to prospectively evaluate the relative utility of two craving questionnaires to predict opioid use among opioid dependent patients in treatment. Method Opioid dependent patients (n=147) initiating buprenorphine treatment were assessed for three months. Craving was measured using: 1) the Desires for Drug Questionnaire (DDQ) and 2) the Penn Alcohol-Craving Scale adapted for opioid craving (PCS) for this study. Multi-level logistic regression models estimated the effects of craving on the likelihood of opioid use after adjusting for gender, age, ethnicity, education, opioid of choice, frequency of use, pain and depression. In these analyses craving assessed at time t was entered as a time-varying predictor of opioid use at time t+1. Results In adjusted regression models, a 1-point increase in PCS scores (on a 7-point scale) was associated with a significant increase in the odds of opioid use at the subsequent assessment (OR = 1.27, 95% CI 1.08; 1.49, p .05) or DDQ control (OR = 0.97, 95%CI 0.85; 1.11, p > .05) scores. Conclusion Self-reported craving for opioids was associated with subsequent lapse to opioid use among a cohort of patients treated with buprenorphine. PMID:24521036

Differences between opioids

DEFF Research Database (Denmark)

Drewes, Asbjørn; Jensen, Rasmus D.; Nielsen, Lecia M.

2013-01-01

to morphine. Although this approach is recognized as cost-effective in most cases there is solid evidence that, on an individual patient basis, opioids are not all equal. Therefore it is important to have an armamentarium of strong analgesics in clinical practice to ensure a personalized approach in patients...... who do not respond to standard treatment. In this review we highlight differences between opioids in human studies from a pharmacological, experimental, clinical and health economics point of view. We provide evidence that individuals respond differently to opioids, and that general differences......Clinical studies comparing the response and side effects of various opioids have not been able to show robust differences between drugs. Hence, recommendations of the regulatory authorities have been driven by costs with a general tendency in many countries to restrict physician's use of opioids...

Prescription Opioids

Science.gov (United States)

... therapy in a primary care setting struggles with opioid addiction. 4,5,6 Once addicted, it can be ... of drug overdose deaths involving methadone and other opioid analgesics in West Virginia. Addiction 2009;104(9):1541-8. Dunn KM, Saunders ...

Opioid dependence - management in general practice.

Science.gov (United States)

Frei, Matthew

2010-08-01

Addiction to opioids, or opioid dependence, encompasses the biopsychosocial dysfunction seen in illicit heroin injectors, as well as aberrant behaviours in patients prescribed opioids for chronic nonmalignant pain. To outline the management of opioid dependence using opioid pharmacotherapy as part of a comprehensive chronic illness management strategy. The same principles and skills general practitioners employ in chronic illness management underpin the care of patients with opioid dependence. Opioid pharmacotherapy, with the substitution medications methadone and buprenorphine, is an effective management of opioid dependence. Training and regulatory requirements for prescribing opioid pharmacotherapies vary between jurisdictions, but this treatment should be within the scope of most Australian GPs.

Computer simulations of neural mechanisms explaining upper and lower limb excitatory neural coupling

Directory of Open Access Journals (Sweden)

Ferris Daniel P

2010-12-01

Full Text Available Abstract Background When humans perform rhythmic upper and lower limb locomotor-like movements, there is an excitatory effect of upper limb exertion on lower limb muscle recruitment. To investigate potential neural mechanisms for this behavioral observation, we developed computer simulations modeling interlimb neural pathways among central pattern generators. We hypothesized that enhancement of muscle recruitment from interlimb spinal mechanisms was not sufficient to explain muscle enhancement levels observed in experimental data. Methods We used Matsuoka oscillators for the central pattern generators (CPG and determined parameters that enhanced amplitudes of rhythmic steady state bursts. Potential mechanisms for output enhancement were excitatory and inhibitory sensory feedback gains, excitatory and inhibitory interlimb coupling gains, and coupling geometry. We first simulated the simplest case, a single CPG, and then expanded the model to have two CPGs and lastly four CPGs. In the two and four CPG models, the lower limb CPGs did not receive supraspinal input such that the only mechanisms available for enhancing output were interlimb coupling gains and sensory feedback gains. Results In a two-CPG model with inhibitory sensory feedback gains, only excitatory gains of ipsilateral flexor-extensor/extensor-flexor coupling produced reciprocal upper-lower limb bursts and enhanced output up to 26%. In a two-CPG model with excitatory sensory feedback gains, excitatory gains of contralateral flexor-flexor/extensor-extensor coupling produced reciprocal upper-lower limb bursts and enhanced output up to 100%. However, within a given excitatory sensory feedback gain, enhancement due to excitatory interlimb gains could only reach levels up to 20%. Interconnecting four CPGs to have ipsilateral flexor-extensor/extensor-flexor coupling, contralateral flexor-flexor/extensor-extensor coupling, and bilateral flexor-extensor/extensor-flexor coupling could enhance

Non-analgesic effects of opioids: management of opioid-induced constipation by peripheral opioid receptor antagonists: prevention or withdrawal?

Science.gov (United States)

Holzer, Peter

2012-01-01

The therapeutic action of opioid analgesics is compromised by peripheral adverse effects among which opioid-induced constipation (OIC) is the most disabling, with a prevalence reported to vary between 15 and 90 %. Although OIC is usually treated with laxatives, there is insufficient clinical evidence that laxatives are efficacious in this indication. In contrast, there is ample evidence from double- blind, randomized and placebo-controlled trials that peripheral opioid receptor antagonists (PORAs) counteract OIC. This specific treatment modality is currently based on subcutaneous methylnaltrexone for the interruption of OIC in patients with advanced illness, and a fixed combination of oral prolonged-release naloxone with prolonged-release oxycodone for the prevention of OIC in the treatment of non-cancer and cancer pain. Both drugs counteract OIC while the analgesic effect of opioids remains unabated. The clinical studies show that more than 50 % of the patients with constipation under opioid therapy may benefit from the use of PORAs, while PORA-resistant patients are likely to suffer from non-opioid-induced constipation, the prevalence of which increases with age. While the addition of naloxone to oxycodone seems to act by preventing OIC, the intermittent dosing of methylnaltrexone every other day seems to stimulate defaecation by provoking an intestinal withdrawal response. The availability of PORAs provides a novel opportunity to specifically control OIC and other peripheral adverse effects of opioid analgesics (e.g., urinary retention and pruritus). The continuous dosing of a PORA has the advantage of few adverse effects, while intermittent dosing of a PORA can be associated with abdominal cramp-like pain.

An N-methyl-D-aspartate receptor mediated large, low-frequency, spontaneous excitatory postsynaptic current in neonatal rat spinal dorsal horn neurons.

Science.gov (United States)

Thomson, L M; Zeng, J; Terman, G W

2006-09-01

Examples of spontaneous oscillating neural activity contributing to both pathological and physiological states are abundant throughout the CNS. Here we report a spontaneous oscillating intermittent synaptic current located in lamina I of the neonatal rat spinal cord dorsal horn. The spontaneous oscillating intermittent synaptic current is characterized by its large amplitude, slow decay time, and low-frequency. We demonstrate that post-synaptic N-methyl-D-aspartate receptors (NMDARs) mediate the spontaneous oscillating intermittent synaptic current, as it is inhibited by magnesium, bath-applied d-2-amino-5-phosphonovalerate (APV), or intracellular MK-801. The NR2B subunit of the NMDAR appears important to this phenomenon, as the NR2B subunit selective NMDAR antagonist, alpha-(4-hydroxphenyl)-beta-methyl-4-benzyl-1-piperidineethanol tartrate (ifenprodil), also partially inhibited the spontaneous oscillating intermittent synaptic current. Inhibition of spontaneous glutamate release by the AMPA/kainate receptor antagonist 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX) or the mu-opioid receptor agonist [D-Ala2, N-Me-Phe4, Gly5] enkephalin-ol (DAMGO) inhibited the spontaneous oscillating intermittent synaptic current frequency. Marked inhibition of spontaneous oscillating intermittent synaptic current frequency by tetrodotoxin (TTX), but not post-synaptic N-(2,6-dimethylphenylcarbamoylmethyl)triethylammonium bromide (QX-314), suggests that the glutamate release important to the spontaneous oscillating intermittent synaptic current is dependent on active neural processes. Conversely, increasing dorsal horn synaptic glutamate release by GABAA or glycine inhibition increased spontaneous oscillating intermittent synaptic current frequency. Moreover, inhibiting glutamate transporters with threo-beta-benzyloxyaspartic acid (DL-TBOA) increased spontaneous oscillating intermittent synaptic current frequency and decay time. A possible functional role of this spontaneous NMDAR

Functional interactions between endogenous cannabinoid and opioid systems: focus on alcohol, genetics and drug-addicted behaviors.

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López-Moreno, J A; López-Jiménez, A; Gorriti, M A; de Fonseca, F Rodríguez

2010-04-01

Although the first studies regarding the endogenous opioid system and addiction were published during the 1940s, addiction and cannabinoids were not addressed until the 1970s. Currently, the number of opioid addiction studies indexed in PubMed-Medline is 16 times greater than the number of cannabinoid addiction reports. More recently, functional interactions have been demonstrated between the endogenous cannabinoid and opioid systems. For example, the cannabinoid brain receptor type 1 (CB1) and mu opioid receptor type 1 (MOR1) co-localize in the same presynaptic nerve terminals and signal through a common receptor-mediated G-protein pathway. Here, we review a great variety of behavioral models of drug addiction and alcohol-related behaviors. We also include data providing clear evidence that activation of the cannabinoid and opioid endogenous systems via WIN 55,512-2 (0.4-10 mg/kg) and morphine (1.0-10 mg/kg), respectively, produces similar levels of relapse to alcohol in operant alcohol self-administration tasks. Finally, we discuss genetic studies that reveal significant associations between polymorphisms in MOR1 and CB1 receptors and drug addiction. For example, the SNP A118G, which changes the amino acid aspartate to asparagine in the MOR1 gene, is highly associated with altered opioid system function. The presence of a microsatellite polymorphism of an (AAT)n triplet near the CB1 gene is associated with drug addiction phenotypes. But, studies exploring haplotypes with regard to both systems, however, are lacking.

Opioid system and human emotions.

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Nummenmaa, Lauri; Tuominen, Lauri

2017-04-10

Emotions are states of vigilant readiness that guide human and animal behaviour during survival-salient situations. Categorical models of emotions posit neurally and physiologically distinct basic human emotions (anger, fear, disgust, happiness, sadness and surprise) that govern different survival functions. Opioid receptors are expressed abundantly in the mammalian emotion circuit, and the opioid system modulates a variety of functions related to arousal and motivation. Yet, its specific contribution to different basic emotions has remained poorly understood. Here, we review how the endogenous opioid system and particularly the μ receptor contribute to emotional processing in humans. Activation of the endogenous opioid system is consistently associated with both pleasant and unpleasant emotions. In general, exogenous opioid agonists facilitate approach-oriented emotions (anger, pleasure) and inhibit avoidance-oriented emotions (fear, sadness). Opioids also modulate social bonding and affiliative behaviour, and prolonged opioid abuse may render both social bonding and emotion recognition circuits dysfunctional. However, there is no clear evidence that the opioid system is able to affect the emotions associated with surprise and disgust. Taken together, the opioid systems contribute to a wide array of positive and negative emotions through their general ability to modulate the approach versus avoidance motivation associated with specific emotions. Because of the protective effects of opioid system-mediated prosociality and positive mood, the opioid system may constitute an important factor contributing to psychological and psychosomatic resilience. © 2017 The British Pharmacological Society.

Biased Agonism of Endogenous Opioid Peptides at the μ-Opioid Receptor.

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Thompson, Georgina L; Lane, J Robert; Coudrat, Thomas; Sexton, Patrick M; Christopoulos, Arthur; Canals, Meritxell

2015-08-01

Biased agonism is having a major impact on modern drug discovery, and describes the ability of distinct G protein-coupled receptor (GPCR) ligands to activate different cell signaling pathways, and to result in different physiologic outcomes. To date, most studies of biased agonism have focused on synthetic molecules targeting various GPCRs; however, many of these receptors have multiple endogenous ligands, suggesting that "natural" bias may be an unappreciated feature of these GPCRs. The μ-opioid receptor (MOP) is activated by numerous endogenous opioid peptides, remains an attractive therapeutic target for the treatment of pain, and exhibits biased agonism in response to synthetic opiates. The aim of this study was to rigorously assess the potential for biased agonism in the actions of endogenous opioids at the MOP in a common cellular background, and compare these to the effects of the agonist d-Ala2-N-MePhe4-Gly-ol enkephalin (DAMGO). We investigated activation of G proteins, inhibition of cAMP production, extracellular signal-regulated kinase 1 and 2 phosphorylation, β-arrestin 1/2 recruitment, and MOP trafficking, and applied a novel analytical method to quantify biased agonism. Although many endogenous opioids displayed signaling profiles similar to that of DAMGO, α-neoendorphin, Met-enkephalin-Arg-Phe, and the putatively endogenous peptide endomorphin-1 displayed particularly distinct bias profiles. These may represent examples of natural bias if it can be shown that they have different signaling properties and physiologic effects in vivo compared with other endogenous opioids. Understanding how endogenous opioids control physiologic processes through biased agonism can reveal vital information required to enable the design of biased opioids with improved pharmacological profiles and treat diseases involving dysfunction of the endogenous opioid system. Copyright © 2015 by The American Society for Pharmacology and Experimental Therapeutics.

Effects of Neuromodulation on Excitatory-Inhibitory Neural Network Dynamics Depend on Network Connectivity Structure

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Rich, Scott; Zochowski, Michal; Booth, Victoria

2018-01-01

Acetylcholine (ACh), one of the brain's most potent neuromodulators, can affect intrinsic neuron properties through blockade of an M-type potassium current. The effect of ACh on excitatory and inhibitory cells with this potassium channel modulates their membrane excitability, which in turn affects their tendency to synchronize in networks. Here, we study the resulting changes in dynamics in networks with inter-connected excitatory and inhibitory populations (E-I networks), which are ubiquitous in the brain. Utilizing biophysical models of E-I networks, we analyze how the network connectivity structure in terms of synaptic connectivity alters the influence of ACh on the generation of synchronous excitatory bursting. We investigate networks containing all combinations of excitatory and inhibitory cells with high (Type I properties) or low (Type II properties) modulatory tone. To vary network connectivity structure, we focus on the effects of the strengths of inter-connections between excitatory and inhibitory cells (E-I synapses and I-E synapses), and the strengths of intra-connections among excitatory cells (E-E synapses) and among inhibitory cells (I-I synapses). We show that the presence of ACh may or may not affect the generation of network synchrony depending on the network connectivity. Specifically, strong network inter-connectivity induces synchronous excitatory bursting regardless of the cellular propensity for synchronization, which aligns with predictions of the PING model. However, when a network's intra-connectivity dominates its inter-connectivity, the propensity for synchrony of either inhibitory or excitatory cells can determine the generation of network-wide bursting.

Changing patterns in opioid addiction

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Sproule, Beth; Brands, Bruna; Li, Selina; Catz-Biro, Laura

2009-01-01

ABSTRACT OBJECTIVE To evaluate the clinical observation that the number of individuals seeking opioid detoxification from oxycodone was increasing at the Centre for Addiction and Mental Health (CAMH) in Toronto, Ont; and to identify the characteristics of individuals seeking opioid detoxification at CAMH. DESIGN Retrospective analysis of patient health records. SETTING Medical Withdrawal Management Service at CAMH. PARTICIPANTS All patients admitted for opioid detoxification between January 2000 and December 2004. MAIN OUTCOME MEASURES Number of opioid detoxification admissions each year; type, dose, and source of opioids; comorbid problems and symptoms. RESULTS There were 571 opioid detoxification admissions during the 5-year study period. The number of admissions increased steadily over the 5 years; in particular, the number of admissions related to controlled-release oxycodone increased substantially (3.8%, 8.3%, 20.8%, 30.6%, and 55.4% of the total opioid admissions in 2000 to 2004, respectively; χ42= 105.5, P < .001). The rates of admissions involving heroin remained low and stable. Use of controlled-release oxycodone was associated with considerably higher doses than use of other prescription opioids was. Physician prescriptions were the source of the prescription opioids for a large percentage of patients, particularly for older patients. Prescription opioid users reported considerable comorbid substance use problems, pain, and psychiatric symptoms. CONCLUSION This study has demonstrated a significant rise in the number of individuals seeking treatment at CAMH for controlled-release oxycodone addiction. The substantial comorbid pain, psychiatric symptoms, and other psychoactive substance use problems in these patients, coupled with the finding that prescriptions were an important source of opioids, highlight the clinical complexities encountered in the treatment of these individuals. Further research examining these complexities and the many possible

Distinct roles of exogenous opioid agonists and endogenous opioid peptides in the peripheral control of neuropathy-triggered heat pain.

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Labuz, Dominika; Celik, Melih Ö; Zimmer, Andreas; Machelska, Halina

2016-09-08

Neuropathic pain often results from peripheral nerve damage, which can involve immune response. Local leukocyte-derived opioid peptides or exogenous opioid agonists inhibit neuropathy-induced mechanical hypersensitivity in animal models. Since neuropathic pain can also be augmented by heat, in this study we investigated the role of opioids in the modulation of neuropathy-evoked heat hypersensitivity. We used a chronic constriction injury of the sciatic nerve in wild-type and opioid peptide-knockout mice, and tested opioid effects in heat and mechanical hypersensitivity using Hargreaves and von Frey tests, respectively. We found that although perineural exogenous opioid agonists, including peptidergic ligands, were effective, the endogenous opioid peptides β-endorphin, Met-enkephalin and dynorphin A did not alleviate heat hypersensitivity. Specifically, corticotropin-releasing factor, an agent triggering opioid peptide secretion from leukocytes, applied perineurally did not attenuate heat hypersensitivity in wild-type mice. Exogenous opioids, also shown to release opioid peptides via activation of leukocyte opioid receptors, were equally analgesic in wild-type and opioid peptide-knockout mice, indicating that endogenous opioids do not contribute to exogenous opioid analgesia in heat hypersensitivity. Furthermore, exogenously applied opioid peptides were ineffective as well. Conversely, opioid peptides relieved mechanical hypersensitivity. Thus, both opioid type and sensory modality may determine the outcome of neuropathic pain treatment.

Opioid Abuse and Addiction - Multiple Languages

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... Spanish) PDF The basics - Opioids, part 1 - English MP3 The basics - Opioids, part 1 - español (Spanish) MP3 The basics - Opioids, part 1 - English MP4 The ... español (Spanish) PDF Pain - Opioids, part 2 - English MP3 Pain - Opioids, part 2 - español (Spanish) MP3 Pain - ...

Biotinylated human. beta. -endorphins as probes for the opioid receptor

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Hochhaus, G.; Gibson, B.W.; Sadee, W.

1988-01-05

The reaction of human ..beta..-endorphin and biotinyl N-hydroxysuccinimide with or without spacer arm, afforded a series of products that were separated by high performance liquid chromatography (HPLC). Liquid secondary ion mass spectrometry of the biotinylated products and their tryptic digests produced abundant protonated molecular ions (MH/sup +/), which specified the number and location of biotinylation. Between 1 and 4 biotinyl residues were incorporated per human ..beta..-endorphin molecule, at Lys-9, -19, -24, -28, and -29, but not at the amino-terminal Try-1. Three HPLC fractions were isolated for receptor binding studies monobiotinylation of Lys-9, Lys-19, and a mixture of Lys-24, Lys-28, and Lys-29 derivatives. IC/sub 50/ values for binding to ..mu.. and delta opioid receptor sites were 3-8 times higher for monobiotinylated derivatives than for the parent human ..beta..-endorphin. Association with avidin decreased opioid receptor affinities for the C/sub 6/ spacer derivative biotinylated at position Lys-9, which is close to the (1-5) enkephalin receptor region. In contrast, avidin did not affect or even increased apparent affinities to ..mu.. and delta sites for derivatives biotinylated at the ..cap alpha..-helical part of the molecule (Lys-19, -24, -28, and -29). Biotinylated human ..beta..-endorphins also bound to low affinity nonopioid binding sites on NG-108-15 cells; however, affinities to these sites were considerably reduced when derivatives were bound to avidin. The ability of biotinylated human ..beta..-endorphin to cross-link the ..mu.. and delta opioid receptors to avidin allows application of the biotin-avidin system as a molecular probe of the opioid receptor.

Is this ?complicated? opioid withdrawal?

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Parkar, S.R.; Seethalakshmi, R; Adarkar, S; Kharawala, S

2006-01-01

Seven patients with opioid dependence admitted in the de-addiction centre for detoxification developed convulsions and delirium during the withdrawal phase. After ruling out all other possible causes of these complications, opioid withdrawal seemed to emerge as the most likely explanation. The unpredictability of the course of opioid dependence and withdrawal needs to be considered when treating patients with opioid dependence.

Gabapentin, opioids, and the risk of opioid-related death: A population-based nested case-control study.

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Tara Gomes

2017-10-01

Full Text Available Prescription opioid use is highly associated with risk of opioid-related death, with 1 of every 550 chronic opioid users dying within approximately 2.5 years of their first opioid prescription. Although gabapentin is widely perceived as safe, drug-induced respiratory depression has been described when gabapentin is used alone or in combination with other medications. Because gabapentin and opioids are both commonly prescribed for pain, the likelihood of co-prescription is high. However, no published studies have examined whether concomitant gabapentin therapy is associated with an increased risk of accidental opioid-related death in patients receiving opioids. The objective of this study was to investigate whether co-prescription of opioids and gabapentin is associated with an increased risk of accidental opioid-related mortality.We conducted a population-based nested case-control study among opioid users who were residents of Ontario, Canada, between August 1, 1997, and December 31, 2013, using administrative databases. Cases, defined as opioid users who died of an opioid-related cause, were matched with up to 4 controls who also used opioids on age, sex, year of index date, history of chronic kidney disease, and a disease risk index. After matching, we included 1,256 cases and 4,619 controls. The primary exposure was concomitant gabapentin use in the 120 days preceding the index date. A secondary analysis characterized gabapentin dose as low (<900 mg daily, moderate (900 to 1,799 mg daily, or high (≥1,800 mg daily. A sensitivity analysis examined the effect of concomitant nonsteroidal anti-inflammatory drug (NSAID use in the preceding 120 days. Overall, 12.3% of cases (155 of 1,256 and 6.8% of controls (313 of 4,619 were prescribed gabapentin in the prior 120 days. After multivariable adjustment, co-prescription of opioids and gabapentin was associated with a significantly increased odds of opioid-related death (odds ratio [OR] 1.99, 95% CI

Reasons for opioid use among patients with dependence on prescription opioids: the role of chronic pain.

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Weiss, Roger D; Potter, Jennifer Sharpe; Griffin, Margaret L; McHugh, R Kathryn; Haller, Deborah; Jacobs, Petra; Gardin, John; Fischer, Dan; Rosen, Kristen D

2014-08-01

The number of individuals seeking treatment for prescription opioid dependence has increased dramatically, fostering a need for research on this population. The aim of this study was to examine reasons for prescription opioid use among 653 participants with and without chronic pain, enrolled in the Prescription Opioid Addiction Treatment Study, a randomized controlled trial of treatment for prescription opioid dependence. Participants identified initial and current reasons for opioid use. Participants with chronic pain were more likely to report pain as their primary initial reason for use; avoiding withdrawal was rated as the most important reason for current use in both groups. Participants with chronic pain rated using opioids to cope with physical pain as more important, and using opioids in response to social interactions and craving as less important, than those without chronic pain. Results highlight the importance of physical pain as a reason for opioid use among patients with chronic pain. Copyright © 2014 Elsevier Inc. All rights reserved.

Amino acids as dietary excitotoxins: a contribution to understanding neurodegenerative disorders.

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Meldrum, B

1993-01-01

The possibility that some acidic amino acids occurring naturally or as additives in the diet can act as excitotoxins producing central nervous system pathology has been the subject of extensive debate in the last 20 years and is here reviewed. High doses of glutamate, aspartate or related excitatory amino acids given in isolation to neonatal rodents produce acute degeneration organs. Neuropathology resulting from consumption of glutamate or aspartate has not been described in man. Various unusual amino acids of plant origin can produce acute excitotoxic syndromes. In man domoate (consumed in mussels that have fed on (Nitschia pungens) can produce an acute syndrome associated with limbic system lesions and anterograde amnesia. Kainate and domoate produce similar syndromes in rodents; acromelate produces spinal pathology. The mechanisms and manifestations of chronic excitotoxicity are less clearly established. A combination of impaired energy metabolism or impaired buffering of calcium and free radicals and endogenous or exogenous excitotoxins may contribute to neuronal loss in human neurodegenerative disorders.

Who Benefits from Chronic Opioid Therapy? Rethinking the Question of Opioid Misuse Risk

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Elizabeth Huber

2016-05-01

Full Text Available Beginning in the late 1990s, a movement began within the pain management field focused upon the underutilization of opioids, thought to be a potentially safe and effective class of pain medication. Concern for addiction and misuse were present at the start of this shift within pain medicine, and an emphasis was placed on developing reliable and valid methods and measures of identifying those at risk for opioid misuse. Since that time, the evidence for the safety and effectiveness of chronic opioid therapy (COT has not been established. Rather, the harmful, dose-dependent deleterious effects have become clearer, including addiction, increased risk of injuries, respiratory depression, opioid induced hyperalgesia, and death. Still, many individuals on low doses of opioids for long periods of time appear to have good pain control and retain social and occupational functioning. Therefore, we propose that the question, “Who is at risk of opioid misuse?” should evolve to, “Who may benefit from COT?” in light of the current evidence.

Genetics Home Reference: opioid addiction

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... Facebook Twitter Home Health Conditions Opioid addiction Opioid addiction Printable PDF Open All Close All Enable Javascript to view the expand/collapse boxes. Description Opioid addiction is a long-lasting (chronic) disease that can ...

The opioid manager: a point-of-care tool to facilitate the use of the Canadian Opioid Guideline.

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Furlan, Andrea D; Reardon, Rhoda; Salach, Lena

2012-01-01

The Opioid Manager is designed to be used as a point-of-care tool for providers prescribing opioids for chronic noncancer pain. It condenses the key elements from the Canadian Opioid Guideline and can be used as a chart insert. The Opioid Manager has been validated and is available for download from the Guideline's Web site http://nationalpaincentre.mcmaster.ca/opioidmanager/. The Opioid Manager is divided into the following four parts: A) before you write the first script, B) initiation trial, C) maintenance and monitoring, and D) when is it time to decrease the dose or stop the opioid completely? The Opioid Manager has been downloaded by 1,432 users: 47 percent family physicians, 18 percent pharmacists, 13 percent other physicians, and 22 percent miscellaneous. To show how to use the Opioid Manager, the authors created a 10-minute video that is available on the Internet. The Opioid Manager is being translated to French, Spanish, Portuguese, and Farsi.

Opioid-Induced Glial Activation: Mechanisms of Activation and Implications for Opioid Analgesia, Dependence, and Reward

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Mark R. Hutchinson

2007-01-01

Full Text Available This review will introduce the concept of toll-like receptor (TLR–mediated glial activation as central to all of the following: neuropathic pain, compromised acute opioid analgesia, and unwanted opioid side effects (tolerance, dependence, and reward. Attenuation of glial activation has previously been demonstrated both to alleviate exaggerated pain states induced by experimental pain models and to reduce the development of opioid tolerance. Here we demonstrate that selective acute antagonism of TLR4 results in reversal of neuropathic pain as well as potentiation of opioid analgesia. Attenuating central nervous system glial activation was also found to reduce the development of opioid dependence, and opioid reward at a behavioral (conditioned place preference and neurochemical (nucleus accumbens microdialysis of morphine-induced elevations in dopamine level of analysis. Moreover, a novel antagonism of TLR4 by (+- and (˗-isomer opioid antagonists has now been characterized, and both antiallodynic and morphine analgesia potentiating activity shown. Opioid agonists were found to also possess TLR4 agonistic activity, predictive of glial activation. Targeting glial activation is a novel and as yet clinically unexploited method for treatment of neuropathic pain. Moreover, these data indicate that attenuation of glial activation, by general or selective TLR antagonistic mechanisms, may also be a clinical method for separating the beneficial (analgesia and unwanted (tolerance, dependence, and reward actions of opioids, thereby improving the safety and efficacy of their use.

Spatial distribution of excitatory synapses on the dendrites of ganglion cells in the mouse retina.

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Yin-Peng Chen

Full Text Available Excitatory glutamatergic inputs from bipolar cells affect the physiological properties of ganglion cells in the mammalian retina. The spatial distribution of these excitatory synapses on the dendrites of retinal ganglion cells thus may shape their distinct functions. To visualize the spatial pattern of excitatory glutamatergic input into the ganglion cells in the mouse retina, particle-mediated gene transfer of plasmids expressing postsynaptic density 95-green fluorescent fusion protein (PSD95-GFP was used to label the excitatory synapses. Despite wide variation in the size and morphology of the retinal ganglion cells, the expression of PSD95 puncta was found to follow two general rules. Firstly, the PSD95 puncta are regularly spaced, at 1-2 µm intervals, along the dendrites, whereby the presence of an excitatory synapse creates an exclusion zone that rules out the presence of other glutamatergic synaptic inputs. Secondly, the spatial distribution of PSD95 puncta on the dendrites of diverse retinal ganglion cells are similar in that the number of excitatory synapses appears to be less on primary dendrites and to increase to a plateau on higher branch order dendrites. These observations suggest that synaptogenesis is spatially regulated along the dendritic segments and that the number of synaptic contacts is relatively constant beyond the primary dendrites. Interestingly, we also found that the linear puncta density is slightly higher in large cells than in small cells. This may suggest that retinal ganglion cells with a large dendritic field tend to show an increased connectivity of excitatory synapses that makes up for their reduced dendrite density. Mapping the spatial distribution pattern of the excitatory synapses on retinal ganglion cells thus provides explicit structural information that is essential for our understanding of how excitatory glutamatergic inputs shape neuronal responses.

Chronic Opioid Use After Surgery: Implications for Perioperative Management in the Face of the Opioid Epidemic.

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Hah, Jennifer M; Bateman, Brian T; Ratliff, John; Curtin, Catherine; Sun, Eric

2017-11-01

Physicians, policymakers, and researchers are increasingly focused on finding ways to decrease opioid use and overdose in the United States both of which have sharply increased over the past decade. While many efforts are focused on the management of chronic pain, the use of opioids in surgical patients presents a particularly challenging problem requiring clinicians to balance 2 competing interests: managing acute pain in the immediate postoperative period and minimizing the risks of persistent opioid use after the surgery. Finding ways to minimize this risk is particularly salient in light of a growing literature suggesting that postsurgical patients are at increased risk for chronic opioid use. The perioperative care team, including surgeons and anesthesiologists, is poised to develop clinical- and systems-based interventions aimed at providing pain relief in the immediate postoperative period while also reducing the risks of opioid use longer term. In this paper, we discuss the consequences of chronic opioid use after surgery and present an analysis of the extent to which surgery has been associated with chronic opioid use. We follow with a discussion of the risk factors that are associated with chronic opioid use after surgery and proceed with an analysis of the extent to which opioid-sparing perioperative interventions (eg, nerve blockade) have been shown to reduce the risk of chronic opioid use after surgery. We then conclude with a discussion of future research directions.

Characteristics of opioid-users whose death was related to opioid-toxicity: a population-based study in Ontario, Canada.

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Parvaz Madadi

Full Text Available The impact of the prescription opioid public health crisis has been illustrated by the dramatic increase in opioid-related deaths in North America. We aimed to identify patterns and characteristics amongst opioid-users whose cause of death was related to opioid toxicity.This was a population-based study of Ontarians between the years 2006 and 2008. All drug-related deaths which occurred during this time frame were reviewed at the Office of the Chief Coroner of Ontario, and opioid-related deaths were identified. Medical, toxicology, pathology, and police reports were comprehensively reviewed. Narratives, semi-quantitative, and quantitative variables were extracted, tabulated, and analyzed.Out of 2330 drug-related deaths in Ontario, 58% were attributed either in whole or in part, to opioids (n = 1359. Oxycodone was involved in approximately one-third of all opioid-related deaths. At least 7% of the entire cohort used opioids that were prescribed for friends and/or family, 19% inappropriately self-administered opioids (injection, inhalation, chewed patch, 3% were recently released from jail, and 5% had been switched from one opioid to another near the time of death. Accidental deaths were significantly associated with personal history of substance abuse, enrollment in methadone maintenance programs, cirrhosis, hepatitis, and cocaine use. Suicides were significantly associated with mental illness, previous suicide attempts, chronic pain, and a history of cancer.These results identify novel, susceptible groups of opioid-users whose cause of death was related to opioids in Ontario and provide the first evidence to assist in quantifying the contribution of opioid misuse and diversion amongst opioid-related mortality in Canada. Multifaceted prevention strategies need to be developed based on subpopulations of opioid users.

Degree of synchronization modulated by inhibitory neurons in clustered excitatory-inhibitory recurrent networks

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Li, Huiyan; Sun, Xiaojuan; Xiao, Jinghua

2018-01-01

An excitatory-inhibitory recurrent neuronal network is established to numerically study the effect of inhibitory neurons on the synchronization degree of neuronal systems. The obtained results show that, with the number of inhibitory neurons and the coupling strength from an inhibitory neuron to an excitatory neuron increasing, inhibitory neurons can not only reduce the synchronization degree when the synchronization degree of the excitatory population is initially higher, but also enhance it when it is initially lower. Meanwhile, inhibitory neurons could also help the neuronal networks to maintain moderate synchronized states. In this paper, we call this effect as modulation effect of inhibitory neurons. With the obtained results, it is further revealed that the ratio of excitatory neurons to inhibitory neurons being nearly 4 : 1 is an economic and affordable choice for inhibitory neurons to realize this modulation effect.

Illicit Opioid Intoxication: Diagnosis and Treatment

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A. Fareed

2011-01-01

Full Text Available Opioid intoxications and overdose are associated with high rates of morbidity and mortality. Opioid overdose may occur in the setting of intravenous or intranasal heroin use, illicit use of diverted opioid medications, intentional or accidental misuse of prescription pain medications, or iatrogenic overdose. In this review, we focused on the epidemiology of illict opioid use in the United States and on the mechanism of action of opioid drugs. We also described the signs and symptoms, and diagnoses of intoxication and overdose. Lastly, we updated the reader about the most recent recommendations for treatment and prevention of opioid intoxications and overdose.

The opioid epidemic and national guidelines for opioid therapy for chronic noncancer pain: a perspective from different continents.

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Häuser, Winfried; Schug, Stephan; Furlan, Andrea D

2017-05-01

A marked rise in opioid prescriptions for patients with chronic noncancer pain (CNCP) with a parallel increase in opioid abuse/misuse, and resulting deaths was noted in the Unites states in the past decade (opioid epidemic). In response, the US Center of Diseases Control (CDC) developed a guideline for prescribing of opioids for patients with CNCP. To assess (1) if there is an opioid epidemic in Australia, Canada, and Germany (2) to compare Australian, Canadian, German, and Center of Diseases Control guidelines recommendations for long-term opioid therapy for CNCP. National evidence-based guidelines and PubMed were searched for recommendations for opioid prescriptions for CNCP. There are signs of an opioid epidemic in Australia and Canada, but not in Germany. Guidelines in all 4 countries provide similar recommendations: opioids are not the first-line therapy for patients with CNCP; regular clinical assessments of benefits and harms are necessary; excessive doses should be avoided (recommended morphine equivalent daily doses range from 50 to 200 mg/d); stopping rules should be followed. All guidelines do not recommend the use of opioids in chronic pain conditions without an established nociceptive or neuropathic cause such as fibromyalgia and primary headache. Implementation of opioid prescribing guidelines should ensure that physicians prescribe opioids only for appropriate indications in limited doses for selected patients and advice patients on their safe use. These measures could contribute to reduce prescription opioid misuse/abuse and deaths.

Feeding Releases Endogenous Opioids in Humans.

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Tuulari, Jetro J; Tuominen, Lauri; de Boer, Femke E; Hirvonen, Jussi; Helin, Semi; Nuutila, Pirjo; Nummenmaa, Lauri

2017-08-23

The endogenous opioid system supports a multitude of functions related to appetitive behavior in humans and animals, and it has been proposed to govern hedonic aspects of feeding thus contributing to the development of obesity. Here we used positron emission tomography to investigate whether feeding results in hedonia-dependent endogenous opioid release in humans. Ten healthy males were recruited for the study. They were scanned with the μ-opioid-specific ligand [ 11 C]carfentanil three times, as follows: after a palatable meal, a nonpalatable meal, and after an overnight fast. Subjective mood, satiety, and circulating hormone levels were measured. Feeding induced significant endogenous opioid release throughout the brain. This response was more pronounced following a nonpalatable meal versus a palatable meal, and independent of the subjective hedonic responses to feeding. We conclude that feeding consistently triggers cerebral opioid release even in the absence of subjective pleasure associated with feeding, suggesting that metabolic and homeostatic rather than exclusively hedonic responses play a role in the feeding-triggered cerebral opioid release. SIGNIFICANCE STATEMENT The endogenous opioid system supports both hedonic and homeostatic functions. It has been proposed that overeating and concomitant opioid release could downregulate opioid receptors and promote the development of obesity. However, it remains unresolved whether feeding leads to endogenous opioid release in humans. We used in vivo positron emission tomography to test whether feeding triggers cerebral opioid release and whether this response is associated with pleasurable sensations. We scanned volunteers using the μ-opioid receptor-specific radioligand [ 11 C]carfentanil three times, as follows: after an overnight fast, after consuming a palatable meal, and after consuming a nonpalatable meal. Feeding led to significant endogenous opioid release, and this occurred also in the absence of feeding

Selective synaptic targeting of the excitatory and inhibitory presynaptic organizers FGF22 and FGF7.

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Terauchi, Akiko; Timmons, Kendall M; Kikuma, Koto; Pechmann, Yvonne; Kneussel, Matthias; Umemori, Hisashi

2015-01-15

Specific formation of excitatory and inhibitory synapses is crucial for proper functioning of the brain. Fibroblast growth factor 22 (FGF22) and FGF7 are postsynaptic-cell-derived presynaptic organizers necessary for excitatory and inhibitory presynaptic differentiation, respectively, in the hippocampus. For the establishment of specific synaptic networks, these FGFs must localize to appropriate synaptic locations - FGF22 to excitatory and FGF7 to inhibitory postsynaptic sites. Here, we show that distinct motor and adaptor proteins contribute to intracellular microtubule transport of FGF22 and FGF7. Excitatory synaptic targeting of FGF22 requires the motor proteins KIF3A and KIF17 and the adaptor protein SAP102 (also known as DLG3). By contrast, inhibitory synaptic targeting of FGF7 requires the motor KIF5 and the adaptor gephyrin. Time-lapse imaging shows that FGF22 moves with SAP102, whereas FGF7 moves with gephyrin. These results reveal the basis of selective targeting of the excitatory and inhibitory presynaptic organizers that supports their different synaptogenic functions. Finally, we found that knockdown of SAP102 or PSD95 (also known as DLG4), which impairs the differentiation of excitatory synapses, alters FGF7 localization, suggesting that signals from excitatory synapses might regulate inhibitory synapse formation by controlling the distribution of the inhibitory presynaptic organizer. © 2015. Published by The Company of Biologists Ltd.

Opioid-free anaesthesia in three dogs

Directory of Open Access Journals (Sweden)

Donna M. White

2017-05-01

Full Text Available Opioid-free anaesthesia (OFA is a relatively new and growing field in human medicine. There are multiple motivations behind this emerging practice with the recognition of several serious potential opioid-related adverse effects including opioid induced hyperalgesia, opioid tolerance and immunomodulatory effects of opioids. Opioids have long been the mainstay of veterinary anaesthesia and pain management practice. The feasibility of OFA in veterinary patients is presented here. A case series of three dogs that underwent OFA for canine ovariohysterectomy is reported. The authors conclude OFA is possible in veterinary medicine; however the move away from the familiar effects of opioids perioperatively is challenging. Gaining experience with these types of protocols for standard procedures in healthy animals, such as neutering, will provide the anaesthetist with the building blocks for more invasive surgeries.

Effect of calcium on excitatory neuromuscular transmission in the crayfish

Science.gov (United States)

Bracho, H.; Orkand, R. K.

1970-01-01

1. The effects of varying the external Ca concentration from 1·8 to 30 mM/l. (⅛-2 times normal) have been studied at the in vitro crayfish excitatory neuromuscular junction. Electrophysiological techniques were used to record transmembrane junctional potentials from muscle fibres and extracellular junctional currents from the vicinity of nerve terminals. 2. The excitatory junctional potential amplitude was proportional to [Ca]0n, where n varied between 0·68 and 0·94 (mean 0·82) when [Ca]0 was varied from 1·8 to 15 mM/l. 3. The increase in junctional potential amplitude on raising [Ca]0 resulted primarily from an increase in the average number of quanta of excitatory transmitter released from the presynaptic nerve terminal by the nerve impulse. 4. The size of the quanta, synaptic delay, presynaptic potential and electrical properties of the muscle membrane were little affected by changes in calcium concentration in the range studied. PMID:5498460

Excitatory amino acid receptor ligands: resolution, absolute stereochemistry, and enantiopharmacology of 2-amino-3-(4-butyl-3-hydroxyisoxazol-5-yl)propionic acid

DEFF Research Database (Denmark)

Johansen, T N; Ebert, B; Bräuner-Osborne, Hans

1998-01-01

(RS)-2-Amino-3-(4-butyl-3-hydroxyisoxazol-5-yl)propionic acid (Bu-HIBO, 6) has previously been shown to be an agonist at (RS)-2-amino-3-(3-hydroxy-5-methylisoxazol-4-yl)propionic acid (AMPA) receptors and an inhibitor of CaCl2-dependent [3H]-(S)-glutamic acid binding (J. Med. Chem. 1992, 35, 3512......-3519). To elucidate the pharmacological significance of this latter binding affinity, which is also shown by quisqualic acid (3) but not by AMPA, we have now resolved Bu-HIBO via diastereomeric salt formation using the diprotected Bu-HIBO derivative 11 and the enantiomers of 1-phenylethylamine (PEA). The absolute...... equipotent as inhibitors of CaCl2-dependent [3H]-(S)-glutamic acid binding, neither enantiomer showed significant affinity for the synaptosomal (S)-glutamic acid uptake system(s). AMPA receptor affinity (IC50 = 0.48 microM) and agonism (EC50 = 17 microM) were shown to reside exclusively in the S...

Macroeconomic conditions and opioid abuse.

Science.gov (United States)

Hollingsworth, Alex; Ruhm, Christopher J; Simon, Kosali

2017-12-01

We examine how deaths and emergency department (ED) visits related to use of opioid analgesics (opioids) and other drugs vary with macroeconomic conditions. As the county unemployment rate increases by one percentage point, the opioid death rate per 100,000 rises by 0.19 (3.6%) and the opioid overdose ED visit rate per 100,000 increases by 0.95 (7.0%). Macroeconomic shocks also increase the overall drug death rate, but this increase is driven by rising opioid deaths. Our findings hold when performing a state-level analysis, rather than county-level; are primarily driven by adverse events among whites; and are stable across time periods. Copyright © 2017 Elsevier B.V. All rights reserved.

Targinact--opioid pain relief without constipation?

Science.gov (United States)

2010-12-01

Targinact (Napp Pharmaceuticals Ltd) is a modified-release combination product containing the strong opioid oxycodone plus the opioid antagonist naloxone. It is licensed for "severe pain, which can be adequately managed only with opioid analgesics".1 The summary of product characteristics (SPC) states that "naloxone is added to counteract opioid-induced constipation by blocking the action of oxycodone at opioid receptors locally in the gut". Advertising for the product claims "better pain relief", "superior GI [gastrointestinal] tolerability" and "improved quality of life" "compared to previous treatment in a clinical practice study (n=7836)". Here we consider whether Targinact offers advantages over using strong opioids plus laxatives where required.

Excitatory components of the mammalian locomotor CPG

DEFF Research Database (Denmark)

Kiehn, Ole; Quinlan, Katharina A.; Restrepo, Carlos Ernesto

2008-01-01

Locomotion in mammals is to a large degree controlled directly by intrinsic spinal networks, called central pattern generators (CPGs). The overall function of these networks is governed by interaction between inhibitory and excitatory neurons. In the present review, we will discuss recent finding...

Do personality traits predict individual differences in excitatory and inhibitory learning?

Directory of Open Access Journals (Sweden)

Zhimin eHe

2013-05-01

Full Text Available Conditioned inhibition (CI is demonstrated in classical conditioning when a stimulus is used to signal the omission of an otherwise expected outcome. This basic learning ability is involved in a wide range of normal behaviour - and thus its disruption could produce a correspondingly wide range of behavioural deficits. The present study employed a computer-based task to measure conditioned excitation and inhibition in the same discrimination procedure. Conditioned inhibition by summation test was clearly demonstrated. Additionally summary measures of excitatory and inhibitory learning (difference scores were calculated in order to explore how performance related to individual differences in a large sample of normal participants (n=176 following exclusion of those not meeting the basic learning criterion. The individual difference measures selected derive from two biologically-based personality theories, Gray’s reinforcement sensitivity theory (1982 and Eysenck’s psychoticism, extraversion and neuroticism theory (1991. Following the behavioural tasks, participants completed the behavioural inhibition system/behavioural activation system scales (BIS/BAS and the Eysenck personality questionnaire revised short scale (EPQ-RS. Analyses of the relationship between scores on each of the scales and summary measures of excitatory and inhibitory learning suggested that those with higher BAS (specifically the drive sub-scale and higher EPQ-RS neuroticism showed reduced levels of excitatory conditioning. Inhibitory conditioning was similarly attenuated in those with higher EPQ-RS neuroticism, as well as in those with higher BIS scores. Thus the findings are consistent with higher levels of neuroticism being accompanied by generally impaired associative learning, both inhibitory and excitatory. There was also evidence for some dissociation in the effects of behavioural activation and behavioural inhibition on excitatory and inhibitory learning respectively.

Risk factors for opioid overdose and awareness of overdose risk among veterans prescribed chronic opioids for addiction or pain.

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Wilder, Christine M; Miller, Shannon C; Tiffany, Elizabeth; Winhusen, Theresa; Winstanley, Erin L; Stein, Michael D

2016-01-01

Rising overdose fatalities among U.S. veterans suggest veterans taking prescription opioids may be at risk for overdose. However, it is unclear whether veterans prescribed chronic opioids are aware of this risk. The objective of this study was to identify risk factors and determine awareness of risk for opioid overdose in veterans treated with opioids for chronic pain, using veterans treated with methadone or buprenorphine for opioid use disorder as a high-risk comparator group. In the current study, 90 veterans on chronic opioid medication, for either opioid use disorder or pain management, completed a questionnaire assessing risk factors, knowledge, and self-estimate of risk for overdose. Nearly all veterans in both groups had multiple overdose risk factors, although individuals in the pain management group had on average a significantly lower total number of risk factors than did individuals in the opioid use disorder group (5.9 versus 8.5, p opioid overdose risk factors (12.1 versus 13.5, p opioid overdose risk factors. Our results suggest that veterans in both groups underestimated their risk for opioid overdose. Expansion of overdose education to include individuals on chronic opioids for pain management and a shift in educational approaches to overdose prevention may be indicated.

Opioids and breast cancer recurrence

DEFF Research Database (Denmark)

Cronin-Fenton, Deirdre P; Heide-Jørgensen, Uffe; Ahern, Thomas P

2015-01-01

BACKGROUND: Opioids may alter immune function, thereby potentially affecting cancer recurrence. The authors investigated the association between postdiagnosis opioid use and breast cancer recurrence. METHODS: Patients with incident, early stage breast cancer who were diagnosed during 1996 through...... 2008 in Denmark were identified from the Danish Breast Cancer Cooperative Group Registry. Opioid prescriptions were ascertained from the Danish National Prescription Registry. Follow-up began on the date of primary surgery for breast cancer and continued until breast cancer recurrence, death......, emigration, 10 years, or July 31, 2013, whichever occurred first. Cox regression models were used to compute hazard ratios and 95% confidence intervals associating breast cancer recurrence with opioid prescription use overall and by opioid type and strength, immunosuppressive effect, chronic use (≥6 months...

Women who abuse prescription opioids: findings from the Addiction Severity Index-Multimedia Version Connect prescription opioid database.

Science.gov (United States)

Green, Traci C; Grimes Serrano, Jill M; Licari, Andrea; Budman, Simon H; Butler, Stephen F

2009-07-01

Evidence suggests gender differences in abuse of prescription opioids. This study aimed to describe characteristics of women who abuse prescription opioids in a treatment-seeking sample and to contrast gender differences among prescription opioid abusers. Data collected November 2005 to April 2008 derived from the Addiction Severity Index Multimedia Version Connect (ASI-MV Connect) database. Bivariate and multivariable logistic regression examined correlates of prescription opioid abuse stratified by gender. 29,906 assessments from 220 treatment centers were included, of which 12.8% (N=3821) reported past month prescription opioid abuse. Women were more likely than men to report use of any prescription opioid (29.8% females vs. 21.1% males, phistory of drug overdose. Men-specific correlates were age screen and identify those at highest risk of prescription opioid abuse. Prevention and intervention efforts with a gender-specific approach are warranted.

Medication-assisted therapy for opioid addiction

OpenAIRE

Tai, Betty; Saxon, Andrew J.; Ling, Walter

2013-01-01

The “Medication-Assisted Therapy for Opioid Addiction” session was chaired by Dr. Betty Tai and had three presenters. The presenters (and their topics) were: Dr. Andrew J. Saxon (Methadone and Buprenorphine for Treatment of Opioid Addiction and HIV Risk Reduction), Dr. Walter Ling (Opioid Antagonist Treatment for Opioid Addiction), and Dr. Betty Tai (Chronic Care Model for Substance Use Disorder).

Excitatory amino acid b-N-methylamino-L-alanine is a putative environmental neurotoxin

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VLADIMIR NEDELJKOV

2011-04-01

Full Text Available The amino acid b-N-methylamino-L-alanine (L-BMAA has been associated with the amyotrophic lateral sclerosis/parkinsonism-dementia complex in three distinct western Pacific populations. The putative neurotoxin is produced by cyanobacteria, which live symbiotically in the roots of cycad trees. L-BMAA was thought to be a threat only to those few populations whose diet and medicines rely heavily on cycad seeds. However, the recent discovery that cyanobacteria from diverse terrestrial, freshwater, and saltwater ecosystems around the world produce the toxin requires a reassessment of whether it poses a larger health threat. Therefore, it is proposed that monitoring L-BMAA levels in cyanobacteria-contaminated water supplies might be prudent.

Peripherally applied opioids for postoperative pain

DEFF Research Database (Denmark)

Nielsen, B N; Henneberg, S W; Schmiegelow, K

2015-01-01

BACKGROUND: Opioids applied peripherally at the site of surgery may produce postoperative analgesia with few side effects. We performed this systematic review to evaluate the analgesic effect of peripherally applied opioids for acute postoperative pain. METHODS: We searched PubMed (1966 to June...... 2013), Embase (1980 to June 2013), and the Cochrane Central Register of Controlled Trials (The Cochrane Library 2013, Issue 6). Randomized controlled trials investigating the postoperative analgesic effect of peripherally applied opioids vs. systemic opioids or placebo, measured by pain intensity...... difference -5 mm, 95% CI: -7 to -3) for peripherally applied opioids vs. placebo and statistically significant increased time to first analgesic (mean difference 153 min, 95% CI: 41-265). When preoperative inflammation was reported (five studies), peripherally applied opioids significantly improved...

[The endogenous opioid system and drug addiction].

Science.gov (United States)

Maldonado, R

2010-01-01

Drug addiction is a chronic brain disorder leading to complex adaptive changes within the brain reward circuits. Several neurotransmitters, including the endogenous opioid system are involved in these changes. The opioid system plays a pivotal role in different aspects of addiction. Thus, opioid receptors and endogenous opioid peptides are largely distributed in the mesolimbic system and modulate dopaminergic activity within the reward circuits. Opioid receptors and peptides are selectively involved in several components of the addictive processes induced by opioids, cannabinoids, psychostimulants, alcohol and nicotine. This review is focused on the contribution of each component of the endogenous opioid system in the addictive properties of the different drugs of abuse. Copyright 2010 Elsevier Masson SAS. All rights reserved.

42 CFR 8.11 - Opioid treatment program certification.

Science.gov (United States)

2010-10-01

... Substances Act (21 U.S.C. 823(g)(1)) to dispense opioid drugs in the treatment of opioid addiction. An OTP... opioid addiction. (2) To obtain certification from SAMHSA, an OTP must meet the Federal opioid treatment... governmental entities to regulate the use of opioid drugs in the treatment of opioid addiction. The provisions...

Electrical field stimulation-induced excitatory responses of ...

African Journals Online (AJOL)

effect of the endothelium on electrical field stimulation (EFS)-induced excitatory responses of pulmonary artery segments from pulmonary hypertensive rats. Methods: Pulmonary hypertension was induced in rats with a single dose of monocrotaline (60 mg/kg) and 21 days later, arterial rings were set up for isometric tension ...

Excitatory amino acid receptor blockade within the caudal pressor area and rostral ventrolateral medulla alters cardiovascular responses to nucleus raphe obscurus stimulation in rats

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Silva N.F.

2002-01-01

Full Text Available Pressor responses elicited by stimulation of the nucleus raphe obscurus (NRO depend on the integrity of the rostral ventrolateral medulla (RVLM. Therefore, to test the participation of excitatory amino acid (EAA receptors in the cardiovascular responses evoked by NRO stimulation (1 ms, 100 Hz, 40-70 µA, for 10 s, the EAA antagonist kynurenic acid (Kyn was microinjected at different sites in the ventrolateral medullar surface (2.7 nmol/200 nl of male Wistar rats (270-320 g, N = 39 and NRO stimulation was repeated. The effects of NRO stimulation were: hypertension (deltaMAP = +43 ± 1 mmHg, P<0.01, bradycardia (deltaHR = -30 ± 7 bpm, P<0.01 and apnea. Bilateral microinjection of Kyn into the RVLM, which did not change baseline parameters, almost abolished the bradycardia induced by NRO stimulation (deltaHR = -61 ± 3 before vs -2 ± 3 bpm after Kyn, P<0.01, N = 7. Unilateral microinjection of Kyn into the CVLM did not change baseline parameters or reduce the pressor response to NRO stimulation (deltaMAP = +46 ± 5 before vs +48 ± 5 mmHg after Kyn, N = 6. Kyn bilaterally microinjected into the caudal pressor area reduced blood pressure and heart rate and almost abolished the pressor response to NRO stimulation (deltaMAP = +46 ± 4 mmHg before vs +4 ± 2 mmHg after Kyn, P<0.01, N = 7. These results indicate that EAA receptors on the medullary ventrolateral surface play a role in the modulation of the cardiovascular responses induced by NRO stimulation, and also suggest that the RVLM participates in the modulation of heart rate responses and that the caudal pressor area modulates the pressor response following NRO stimulation.

Dependence and addiction during chronic opioid therapy.

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Juurlink, David N; Dhalla, Irfan A

2012-12-01

The use of opioids for chronic noncancer pain has increased dramatically over the past 25 years in North America and has been accompanied by a major increase in opioid addiction and overdose deaths. The increase in opioid prescribing is multifactorial and partly reflects concerns about the effectiveness and safety of alternative medications, particularly the nonsteroidal anti-inflammatory drugs. However, much of the rise in opioid prescribing reflects the assertion, widely communicated to physicians in the 1990s, that the risks of dependence and addiction during chronic opioid therapy were low, predictable, and could be minimized by the use of controlled-release opioid formulations. In this narrative review, we offer a critical appraisal of the publications most frequently cited as evidence that the risk of addiction during chronic opioid therapy is low. We conclude that very few well-designed studies support the notion that opioid addiction is rare during chronic opioid therapy and that none can be readily generalized to present-day practice. Despite serious methodological limitations, these studies have been repeatedly mischaracterized as showing that the risk of addiction during chronic opioid therapy is rare. These studies are countered by a larger, more rigorous and contemporary body of evidence demonstrating that dependence and addiction are relatively common consequences of chronic opioid therapy, occurring in up to one-third of patients in some series.

Sequential dynamics in the motif of excitatory coupled elements

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Korotkov, Alexander G.; Kazakov, Alexey O.; Osipov, Grigory V.

2015-11-01

In this article a new model of motif (small ensemble) of neuron-like elements is proposed. It is built with the use of the generalized Lotka-Volterra model with excitatory couplings. The main motivation for this work comes from the problems of neuroscience where excitatory couplings are proved to be the predominant type of interaction between neurons of the brain. In this paper it is shown that there are two modes depending on the type of coupling between the elements: the mode with a stable heteroclinic cycle and the mode with a stable limit cycle. Our second goal is to examine the chaotic dynamics of the generalized three-dimensional Lotka-Volterra model.

Opioids, pain, the brain, and hyperkatifeia: a framework for the rational use of opioids for pain.

Science.gov (United States)

Shurman, Joseph; Koob, George F; Gutstein, Howard B

2010-07-01

Opioids have relieved more human suffering than any other medication, but their use is still fraught with significant concerns of misuse, abuse, and addiction. This theoretical article explores the hypothesis that opioid misuse in the context of pain management produces a hypersensitivity to emotional distress, termed hyperkatifeia. In the misuse of opioids, neural substrates that mediate positive emotional states (brain reward systems) are compromised, and substrates mediating negative emotional states (brain stress systems) are enhanced. A reflection and early marker of such a nonhomeostatic state may be the development of opioid-induced hyperkatifeia, defined as the increased intensity of the constellation of negative emotional/motivational symptoms and signs observed during withdrawal from drugs of abuse (derived from the Greek "katifeia" for dejection or negative emotional state) and is most likely to occur in subjects in whom the opioid produces a break with homeostasis and less likely to occur when the opioid is restoring homeostasis, such as in effective pain treatment. When the opioid appropriately relieves pain, opponent processes are not engaged. However, if the opioid is administered in excess of need because of overdose, pharmacokinetic variables, or treating an individual without pain, then the body will react to that perturbation by engaging opponent processes in the domains of both pain (hyperalgesia) and negative emotional states (hyperkatifeia). Repeated engagement of opponent processes without time for the brain's emotional systems to reestablish homeostasis will further drive changes in emotional processes that may produce opioid abuse or addiction, particularly in individuals with genetic or environmental vulnerability.

Comparison of craving for opioid in opioid-dependent individuals and people under methadone maintenance treatment

Directory of Open Access Journals (Sweden)

Azita Chehri

2014-02-01

Full Text Available Background: Methadone Maintenance Therapy (MMT is the most important treatment for opioid -dependency recurrence. The aim of this study was to compare the craving level in opioid-dependent individuals and people under methadone maintenance therapy. Methods: In this case – control study, 120 men with opioid dependency were selected through cluster sampling method. They were divided into two groups, 60 people in opioid-dependent group and 60 people in MMT group. Both groups were matched for age, sex, marital status, education, duration of opioid dependency and method of consumption. Then, they completed INCAS Substance Abuse Profile (ISAP, opiate withdrawal symptoms checklist, self–report of craving, Desire for Drug Questionnaire (DDQ, Obsessive Compulsive Drug Use Scale (OCDUS and visual cue-induced craving questionnaire. Data were analyzed by SPSS 15 using t-test and ANOVA. Results: Mean craving for drug significantly was lower in MMT group comparing opioid-dependent group (P<0.01. Conclusion: Methadone Maintenance Therapy decreased the craving for drugs and substances This can have an important role in relapse prevention.

Creating opioid dependence in the emergency department.

Science.gov (United States)

Upadhye, Suneel

2018-01-01

Clinical question What is the risk of creating opioid dependence from an ED opioid prescription? Article chosen Barnett ML, Olenski AR, Jena AB. Opioid-prescribing patterns of emergency physicians and risk of long-term use. N Engl J Med 2017;376:663-73, doi:10.1056/NEJMsa1610524. This study examined the risk of creating long-term opioid dependence from a prescription written in an opioid-naive patient in the ED.

Deltorphins: a family of naturally occurring peptides with high affinity and selectivity for delta opioid binding sites.

Science.gov (United States)

Erspamer, V; Melchiorri, P; Falconieri-Erspamer, G; Negri, L; Corsi, R; Severini, C; Barra, D; Simmaco, M; Kreil, G

1989-07-01

Deltorphins are endogenous linear heptapeptides, isolated from skin extracts of frogs belonging to the genus Phyllomedusa, that have a higher affinity and selectivity for delta opioid binding sites than any other natural compound known. Two deltorphins with the sequence Tyr-Ala-Phe-Asp(or Glu)-Val-Val-Gly-NH2 have been isolated from skin extracts of Phyllomedusa bicolor. The alanine in position 2 is in the D configuration. These peptides, [D-Ala2]deltorphins I and II, show an even higher affinity for delta receptors than the previously characterized deltorphin, which contains D-methionine as the second amino acid. These peptides show some similarity to another constituent of Phyllomedusa skin, dermorphin, which is highly selective for mu-opioid receptors. These peptides all have the N-terminal sequence Tyr-D-Xaa-Phe, where D-Xaa is either D-alanine or D-methionine. While this structure seems to be capable of activating both mu and delta opioid receptors, differences in the C-terminal regions of these peptides are probably responsible for the observed high receptor selectivity of dermorphin and deltorphin.

CDC Vital Signs: Opioid Painkiller Prescribing

Science.gov (United States)

... Mental Health Services Administration Medication-Assisted Treatment for Opioid Addiction: Facts for Families and Friends Opioid Overdose Prevention ... Abuse Drugs, Brains, and Behavior: The Science of Addiction Opioid and Pain Management CMEs/CEs Prescription Drugs U.S. ...

Connections between EM2-containing terminals and GABA/μ-opioid receptor co-expressing neurons in the rat spinal trigeminal caudal nucleus

Science.gov (United States)

Li, Meng-Ying; Wu, Zhen-Yu; Lu, Ya-Cheng; Yin, Jun-Bin; Wang, Jian; Zhang, Ting; Dong, Yu-Lin; Wang, Feng

2014-01-01

Endomorphin-2 (EM2) demonstrates a potent antinociceptive effect via the μ-opioid receptor (MOR). To provide morphological evidence for the pain control effect of EM2, the synaptic connections between EM2-immunoreactive (IR) axonal terminals and γ-amino butyric acid (GABA)/MOR co-expressing neurons in lamina II of the spinal trigeminal caudal nucleus (Vc) were investigated in the rat. Dense EM2-, MOR- and GABA-IR fibers and terminals were mainly observed in lamina II of the Vc. Within lamina II, GABA- and MOR-neuronal cell bodies were also encountered. The results of immunofluorescent histochemical triple-staining showed that approximately 14.2 or 18.9% of GABA-IR or MOR-IR neurons also showed MOR- or GABA-immunopositive staining in lamina II; approximately 45.2 and 36.1% of the GABA-IR and MOR-IR neurons, respectively, expressed FOS protein in their nuclei induced by injecting formalin into the left lower lip of the mouth. Most of the GABA/MOR, GABA/FOS, and MOR/FOS double-labeled neurons made close contacts with EM2-IR fibers and terminals. Immuno-electron microscopy confirmed that the EM2-IR terminals formed synapses with GABA-IR or MOR-IR dendritic processes and neuronal cell bodies in lamina II of the Vc. These results suggest that EM2 might participate in pain transmission and modulation by binding to MOR-IR and GABAergic inhibitory interneuron in lamina II of the Vc to exert inhibitory effect on the excitatory interneuron in lamina II and projection neurons in laminae I and III. PMID:25386121

Hiperalgesia Inducida por Opioides

OpenAIRE

Jiménez Salazar, Andrés

2013-01-01

Los opioides producen analgesia a través de un efecto inhibitorio sobre el sistema nociceptivo principalmente. Hasta la fecha, los opioides siguen siendo los analgésicos más potentes para el manejo de dolor moderado a severo. La Asociación Internacional del Estudio del Dolor (IASP, en inglés) define hiperalgesia como "un aumento de la respuesta a un estímulo que normalmente es doloroso". En contraste, está bien establecido que la terapia crónica con opioides se asocia con el desarrollo de ...

The Relative Potency of Inverse Opioid Agonists and a Neutral Opioid Antagonist in Precipitated Withdrawal and Antagonism of Analgesia and Toxicity

OpenAIRE

Sirohi, Sunil; Dighe, Shveta V.; Madia, Priyanka A.; Yoburn, Byron C.

2009-01-01

Opioid antagonists can be classified as inverse agonists and neutral antagonists. In the opioid-dependent state, neutral antagonists are significantly less potent in precipitating withdrawal than inverse agonists. Consequently, neutral opioid antagonists may offer advantages over inverse agonists in the management of opioid overdose. In this study, the relative potency of three opioid antagonists to block opioid analgesia and toxicity and precipitate withdrawal was exa...

Opioid Therapy for Chronic Nonmalignant Pain

Directory of Open Access Journals (Sweden)

Russell K Portenoy

1996-01-01

Full Text Available Long term administration of an opioid drug for chronic nonmalignant pain continues to be controversial, but is no longer uniformly rejected by pain specialists. This is true despite concerns that the regulatory agencies that oversee physician prescribing of opioid drugs continue to stigmatize the practice. The changing clinical perspective has been driven, in part, by widespread acknowledgement of the remarkably favourable outcomes achieved during opioid treatment of cancer pain. These outcomes contrast starkly with popular teaching about chronic opioid therapy and affirm the potential for prolonged efficacy, tolerable side effects, enhanced function associated with improved comfort and minimal risk of aberrant drug-related behaviours consistent with addiction. A large anecdotal experience in populations with nonmalignant pain suggests that these patients are more heterogeneous and that opioid therapy will greatly benefit some and will contribute to negative outcomes for others. The few controlled clinical trials that have been performed support the safety and efficacy of opioid therapy, but have been too limited to ensure generalization to the clinical setting. A critical review of the medical literature pertaining to chronic pain, opioid pharmacology and addiction medicine can clarify misconceptions about opioid therapy and provide a foundation for patient selection and drug administration. The available data support the view that opioids are no panacea for chronic pain, but should be considered in carefully selected patients using clinically derived guidelines that stress a structured approach and ongoing monitoring of efficacy, adverse effects, functional outcomes and the occurrence of aberrant drug-related behaviours.

Long-term course of opioid addiction.

Science.gov (United States)

Hser, Yih-Ing; Evans, Elizabeth; Grella, Christine; Ling, Walter; Anglin, Douglas

2015-01-01

Opioid addiction is associated with excess mortality, morbidities, and other adverse conditions. Guided by a life-course framework, we review the literature on the long-term course of opioid addiction in terms of use trajectories, transitions, and turning points, as well as other factors that facilitate recovery from addiction. Most long-term follow-up studies are based on heroin addicts recruited from treatment settings (mostly methadone maintenance treatment), many of whom are referred by the criminal justice system. Cumulative evidence indicates that opioid addiction is a chronic disorder with frequent relapses. Longer treatment retention is associated with a greater likelihood of abstinence, whereas incarceration is negatively related to subsequent abstinence. Over the long term, the mortality rate of opioid addicts (overdose being the most common cause) is about 6 to 20 times greater than that of the general population; among those who remain alive, the prevalence of stable abstinence from opioid use is low (less than 30% after 10-30 years of observation), and many continue to use alcohol and other drugs after ceasing to use opioids. Histories of sexual or physical abuse and comorbid mental disorders are associated with the persistence of opioid use, whereas family and social support, as well as employment, facilitates recovery. Maintaining opioid abstinence for at least five years substantially increases the likelihood of future stable abstinence. Recent advances in pharmacological treatment options (buprenorphine and naltrexone) include depot formulations offering longer duration of medication; their impact on the long-term course of opioid addiction remains to be assessed.

The prescription opioid epidemic: an overview for anesthesiologists.

Science.gov (United States)

Alam, Asim; Juurlink, David N

2016-01-01

The objectives for preparing this article were to review the historical context and epidemiology surrounding the North American prescription opioid crisis, to summarize the evidence regarding the benefits and harms of long-term opioid therapy for non-cancer pain, and to outline ways in which anesthesiologists may help ameliorate the problem. We searched PubMed, Google Scholar, and EMBASE™ for relevant articles using various search terms, including pain, opioid epidemic, history of opioid use, perioperative care, and addiction. Related citations were further explored and searched depending on the specific subtopic of interest. In the 1980s and early 1990s, opioids were infrequently used for the treatment of chronic pain. Thereafter, however, physicians were gradually inculcated with the message that long-term opioid therapy was a safe and effective treatment option for patients with chronic non-cancer pain. Pharmaceutical companies supported this growing movement and employed aggressive and sometimes misleading marketing strategies for new opioid formulations. As a result, the practice of prescribing opioids flourished in the late 1990s. The surge in prescribing opioids was accompanied by a marked increase in opioid-related morbidity and mortality. This change in practice transpired despite the absence of randomized trials showing clinically significant benefit from the long-term use of opioids. Subsequently, however, a large and growing body of evidence has emerged quantifying the harms associated with long-term opioid therapy. Anesthesiologists widely prescribe opioids for acute and chronic pain; yet, as a group, they may be largely unaware of the current state of this growing epidemic and what role they can play to rectify this problem. Anesthesiologists are well positioned to take a leadership role in the management of postoperative discharge opioid therapy in an effort to curb the overutilization of opioids. Furthermore, anesthesiologists who regularly

Pain Management in the Opioid-Dependent Pregnant Woman.

Science.gov (United States)

Safley, Rebecca R; Swietlikowski, Jamie

Opioid dependence is an epidemic in the United States, and the percentage of pregnant women who are opioid dependent has increased dramatically in the last decade. Pain management, already a concern for intrapartum and postpartum care, is complicated in the context of opioid dependence. This clinical review surveys the literature on pain management in opioid-dependent pregnant women to summarize current consensus and evidence to guide clinical practice. Points of consensus for pain management in opioid-dependent pregnant women include continual opioid maintenance therapy throughout the pregnancy and the postpartum period; adequate management of acute pain; the contraindication of opioid agonist-antagonists for pain management; and the need for interdisciplinary teams using a multimodal approach to provide optimal care to opioid-dependent pregnant women.

The impact of opioids on the endocrine system.

Science.gov (United States)

Katz, Nathaniel; Mazer, Norman A

2009-02-01

Opioids have been used for medicinal and analgesic purposes for centuries. However, their negative effects on the endocrine system, which have been known for some times, are barely discussed in modern medicine. Therefore, we conducted a systematic review of the impact of opioids on the endocrine system. A review of the English language literature on preclinical and clinical studies of any type on the influence of opioids on the endocrine system was conducted. Preliminary recommendations for monitoring and managing these problems were provided. Long-term opioid therapy for either addiction or chronic pain often induces hypogonadism owing to central suppression of hypothalamic secretion of gonadotropin-releasing hormone. Symptoms of opioid-induced hypogonadism include loss of libido, infertility, fatigue, depression, anxiety, loss of muscle strength and mass, osteoporosis, and compression fractures in both men and women; impotence in men; and menstrual irregularities and galactorrhea in women. In view of the increased use of opioids for chronic pain, it has become increasingly important to monitor patients taking opioids and manage endocrine complications. Therefore, patients on opioid therapy should be routinely screened for such symptoms and for laboratory abnormalities in sex hormones. Opioid-induced hypogonadism seems to be a common complication of therapeutic or illicit opioid use. Patients on long-term opioid therapy should be prospectively monitored, and in cases of opioid-induced hypogonadism, we recommend nonopioid pain management, opioid rotation, or sex hormone supplementation after careful consideration of the risks and benefits.

The opioid overdose epidemic: opportunities for pharmacists

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Wu LT

2017-07-01

Full Text Available Li-Tzy Wu,1–4 Udi E Ghitza,5 Anne L Burns,6 Paolo Mannelli,1 1Department of Psychiatry and Behavioral Sciences, 2Department of Medicine, 3Duke Clinical Research Institute, Duke University School of Medicine, 4Center for Child and Family Policy, Sanford School of Public Policy, Duke University, Durham, NC, 5Center for Clinical Trials Network, National Institute on Drug Abuse, Bethesda, MD, 6American Pharmacists Association, Washington, DC, USA The USA is experiencing an opioid overdose epidemic. It has been driven largely by prescription opioids and intensified by a surge of illicit opioids (e.g., heroin and fentanyl.1,2 Drug-involved overdose, mainly opioids (e.g., prescription opioids and heroin, is a leading cause of accidental death in the USA. The opioid overdose epidemic has been escalating consistently for over a decade.2 Every day, an estimated 91 Americans die from opioid-related overdose.3 Opioid overdose appears to have disproportionally affected men, adults aged 25–64 years, and non-Hispanic whites.2

America's Opioid Epidemic: Supply and Demand Considerations.

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Clark, David J; Schumacher, Mark A

2017-11-01

America is in the midst of an opioid epidemic characterized by aggressive prescribing practices, highly prevalent opioid misuse, and rising rates of prescription and illicit opioid overdose-related deaths. Medical and lay public sentiment have become more cautious with respect to prescription opioid use in the past few years, but a comprehensive strategy to reduce our reliance on prescription opioids is lacking. Addressing this epidemic through reductions in unnecessary access to these drugs while implementing measures to reduce demand will be important components of any comprehensive solution. Key supply-side measures include avoiding overprescribing, reducing diversion, and discouraging misuse through changes in drug formulations. Important demand-side measures center around educating patients and clinicians regarding the pitfalls of opioid overuse and methods to avoid unnecessary exposure to these drugs. Anesthesiologists, by virtue of their expertise in the use of these drugs and their position in guiding opioid use around the time of surgery, have important roles to play in reducing patient exposure to opioids and providing education about appropriate use. Aside from the many immediate steps that can be taken, clinical and basic research directed at understanding the interaction between pain and opioid misuse is critical to identifying the optimal use of these powerful pain relievers in clinical practice.

Tourette syndrome and excitatory substances: is there a connection?

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Zou, Li-Ping; Wang, Ying; Zhang, Li-Ping; Zhao, Jian-Bo; Lu, Jin-Fang; Liu, Qun; Wang, Hang-Yan

2011-05-01

The objective of this study is to investigate the relationship between excitatory substances by testing the urine in children with Tourette syndrome (TS). We performed a control study involving 44 patients with TS and 44 normal children by investigating the children's daily eating habits. We used the gas chromatograph-mass spectrometer and liquid chromatograph-mass spectrometer from Agilent. Substances for detection included 197 excitatory substances prohibited by the International Olympic Committee and other substances with similar chemical structures or biological functions for urine samples. Forty-four patients who did not take any drugs in the past 2 weeks enrolled in the study. The positive rate in the experiment group was three cases, while it was negative in the control group. The level of 1-testosterone increased in one extremely severe TS patient who ate large amounts of puffed food and drank an average of 350 ml of cola per day. Cathine and other substances with similar chemical constitution or similar biological effects increased in one severe TS patient who ate bags of instant noodles daily, according to the high score of the Yale Global Tic Severity Scale. An increase in ephedrine type, testosterone, and stimulants may be related to the pathogenesis of TS. Unhealthy food possibly causes TS. The relationship between excitatory substances and TS needs to be explored with the goal of providing more information on diagnosing and treating TS.

Location-dependent excitatory synaptic interactions in pyramidal neuron dendrites.

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Bardia F Behabadi

Full Text Available Neocortical pyramidal neurons (PNs receive thousands of excitatory synaptic contacts on their basal dendrites. Some act as classical driver inputs while others are thought to modulate PN responses based on sensory or behavioral context, but the biophysical mechanisms that mediate classical-contextual interactions in these dendrites remain poorly understood. We hypothesized that if two excitatory pathways bias their synaptic projections towards proximal vs. distal ends of the basal branches, the very different local spike thresholds and attenuation factors for inputs near and far from the soma might provide the basis for a classical-contextual functional asymmetry. Supporting this possibility, we found both in compartmental models and electrophysiological recordings in brain slices that the responses of basal dendrites to spatially separated inputs are indeed strongly asymmetric. Distal excitation lowers the local spike threshold for more proximal inputs, while having little effect on peak responses at the soma. In contrast, proximal excitation lowers the threshold, but also substantially increases the gain of distally-driven responses. Our findings support the view that PN basal dendrites possess significant analog computing capabilities, and suggest that the diverse forms of nonlinear response modulation seen in the neocortex, including uni-modal, cross-modal, and attentional effects, could depend in part on pathway-specific biases in the spatial distribution of excitatory synaptic contacts onto PN basal dendritic arbors.

The changing landscape of opioid prescribing: long-acting and extended-release opioid class-wide Risk Evaluation and Mitigation Strategy

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Gudin JA

2012-05-01

Full Text Available Jeffrey A GudinEnglewood Hospital and Medical Center, Englewood, NJ, USAAbstract: Prescriptions for opioid analgesics to manage moderate-to-severe chronic noncancer pain have increased markedly over the last decade, as have postmarketing reports of adverse events associated with opioids. As an unintentional consequence of greater prescription opioid utilization, there has been the parallel increase in misuse, abuse, and overdose, which are serious risks associated with all opioid analgesics. In response to these concerns, the Food and Drug Administration announced the requirement for a class-wide Risk Evaluation and Mitigation Strategy (REMS for long-acting and extended-release (ER opioid analgesics in April 2011. An understanding of the details of this REMS will be of particular importance to primary care providers. The class-wide REMS is focused on educating health care providers and patients on appropriate prescribing and safe use of ER opioids. Support from primary care will be necessary for the success of this REMS, as these clinicians are the predominant providers of care and the main prescribers of opioid analgesics for patients with chronic pain. Although currently voluntary, future policy will likely dictate that providers undergo mandatory training to continue prescribing medications within this class. This article outlines the elements of the class-wide REMS for ER opioids and clarifies the impact on primary care providers with regard to training, patient education, and clinical practice.Keywords: long-acting opioid, extended-release opioid, risk, REMS, FDA, primary care

Opioid Analgesics and Nicotine: More Than Blowing Smoke.

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Yoon, Jin H; Lane, Scott D; Weaver, Michael F

2015-09-01

Practitioners are highly likely to encounter patients with concurrent use of nicotine products and opioid analgesics. Smokers present with more severe and extended chronic pain outcomes and have a higher frequency of prescription opioid use. Current tobacco smoking is a strong predictor of risk for nonmedical use of prescription opioids. Opioid and nicotinic-cholinergic neurotransmitter systems interact in important ways to modulate opioid and nicotine effects: dopamine release induced by nicotine is dependent on facilitation by the opioid system, and the nicotinic-acetylcholine system modulates self-administration of several classes of abused drugs-including opioids. Nicotine can serve as a prime for the use of other drugs, which in the case of the opioid system may be bidirectional. Opioids and compounds in tobacco, including nicotine, are metabolized by the cytochrome P450 enzyme system, but the metabolism of opioids and tobacco products can be complicated. Accordingly, drug interactions are possible but not always clear. Because of these issues, asking about nicotine use in patients taking opioids for pain is recommended. When assessing patient tobacco use, practitioners should also obtain information on products other than cigarettes, such as cigars, pipes, smokeless tobacco, and electronic nicotine delivery systems (ENDS, or e-cigarettes). There are multiple forms of behavioral therapy and pharmacotherapy available to assist patients with smoking cessation, and opioid agonist maintenance and pain clinics represent underutilized opportunities for nicotine intervention programs.

Patient-reported opioid analgesic requirements after elective inguinal hernia repair: A call for procedure-specific opioid-administration strategies.

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Mylonas, Konstantinos S; Reinhorn, Michael; Ott, Lauren R; Westfal, Maggie L; Masiakos, Peter T

2017-11-01

A better understanding of the analgesia needs of patients who undergo common operative procedures is necessary as we address the growing opioid public health crisis in the United States. The aim of this study was to evaluate patient experience with our opioid prescribing practice after elective inguinal hernia repairs. A prospective, observational study was conducted between October 1, 2015, and September 30, 2016, in a single-surgeon, high-volume, practice of inguinal hernia operation. Adult patients undergoing elective inguinal herniorrhaphy under local anesthesia with intravenous sedation were invited to participate. All patients were prescribed 10 opioid analgesic tablets postoperatively and were counseled to reserve opioids for pain not controlled by nonopioid analgesics. Their experience was captured by completing a questionnaire 2 to 3 weeks postoperatively during their postoperative visit. A total of 185 patients were surveyed. The majority of the participants were males (177, 95.7%) and ≥60 years old (96, 51.9%). Of the 185 patients, 159 (85.9%) reported using ≤4 opioid tablets; 110 patients (59.5%) reported that they used no opioid analgesics postoperatively. None of the patients was taking opioids within 7 days of their postoperative appointment. Of the 147 patients who were employed, 111 (75.5%) reported missing ≤3 work days, 57 of whom (51.4%) missed no work at all. Patients who were employed were more likely to take opioid analgesics postoperatively (P = .049). Patients who took no opioid analgesics experienced less maximum (P require any opioid analgesics, and nearly all of those who thought that they did need opioids used reserved.

Positron Emission Tomography (PET) Imaging of Opioid Receptors

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van Waarde, Aren; Absalom, Anthony; Visser, Anniek; Dierckx, Rudi; Dierckx, Rudi AJO; Otte, Andreas; De Vries, Erik FJ; Van Waarde, Aren; Luiten, Paul GM

2014-01-01

The opioid system consists of opioid receptors (which mediate the actions of opium), their endogenous ligands (the enkephalins, endorphins, endomorphins, dynorphin, and nociceptin), and the proteins involved in opioid production, transport, and degradation. PET tracers for the various opioid

The opioid epidemic and national guidelines for opioid therapy for chronic noncancer pain: a perspective from different continents

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Winfried Häuser

2017-06-01

Conclusion:. Implementation of opioid prescribing guidelines should ensure that physicians prescribe opioids only for appropriate indications in limited doses for selected patients and advice patients on their safe use. These measures could contribute to reduce prescription opioid misuse/abuse and deaths.

Tolerance to non-opioid analgesics is opioid-sensitive in nucleus raphe magnus

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Merab G Tsagareli

2011-07-01

Full Text Available Repeated injection of opioid analgesics can lead to a progressive loss of its effect. This phenomenon is known as tolerance. Several lines of investigations have shown that systemic, intraperitoneal administration or the microinjection of non-opioid analgesics, non-steroidal anti-inflammatory drugs (NSAIDs in the midbrain periaqueductal gray matter induces antinociception with some effects of tolerance. Our recent study has revealed that microinjection of three drugs analgin, ketorolac and xefocam into the central nucleus of amygdala produce tolerance to them and cross-tolerance to morphine. Here we report that repeated administrations of these NSAIDs into the nucleus raphe magnus (NRM in the following four days result in progressively less antinociception, i.e. produce the development of tolerance to these drugs in mail rats. Special control experiments showed that post-treatment with μ-opioid antagonist naloxone in NRM significantly decreased antinociceptive effects of NSAIDs at the first day in behavioral tail flick reflex (TF and hot plate (HP latencies. At the second day, naloxone generally had trend effects in both TF and HP tests impeded the development of tolerance to the antinociceptive effect of non-opioid analgesics. These findings strongly support the suggestion on endogenous opioid involvement in NSAIDs antinociception and tolerance in the descending pain control system. Moreover, repeated injections of NSAIDs progressively lead to tolerance to them, cross-tolerance to morphine and the risk of a withdrawal syndrome. Therefore, these results are important for human medicine too.

Drug interactions: volatile anesthetics and opioids.

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Glass, P S; Gan, T J; Howell, S; Ginsberg, B

1997-09-01

Multiple drugs are used to provide anesthesia. Volatile anesthetics are commonly combined with opioids. Several studies have demonstrated that small doses of opioid (i.e., within the analgesic range) result in a marked reduction in minimum alveolar concentration (MAC) of the volatile anesthetic that will prevent purposeful movement in 50% of patients at skin incision). Further increases in opioid dose provide only a further small reduction in MAC. Thus, a ceiling effect of the opioid is observed at a MAC value of the volatile anesthetic equal to its MAC awake. Recovery from anesthesia when an opioid is combined with a volatile anesthetic is dependent on the rate of decrease of both drugs to their respective concentrations that are associated with adequate spontaneous ventilation and awakening. Through an understanding of the pharmacodynamic interaction of volatile anesthetics with opioids and the pharmacokinetic processes responsible for the recovery from drug effect, optimal dosing schemes can thus be developed. A review of these pharmacodynamic and pharmacokinetic principles that will allow clinicians to administer drugs to provide a more optimal anesthetic is provided.

Genetic controls balancing excitatory and inhibitory synaptogenesis in neurodevelopmental disorder models

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Cheryl L Gatto

2010-06-01

Full Text Available Proper brain function requires stringent balance of excitatory and inhibitory synapse formation during neural circuit assembly. Mutation of genes that normally sculpt and maintain this balance results in severe dysfunction, causing neurodevelopmental disorders including autism, epilepsy and Rett syndrome. Such mutations may result in defective architectural structuring of synaptic connections, molecular assembly of synapses and/or functional synaptogenesis. The affected genes often encode synaptic components directly, but also include regulators that secondarily mediate the synthesis or assembly of synaptic proteins. The prime example is Fragile X syndrome (FXS, the leading heritable cause of both intellectual disability and autism spectrum disorders. FXS results from loss of mRNA-binding FMRP, which regulates synaptic transcript trafficking, stability and translation in activity-dependent synaptogenesis and plasticity mechanisms. Genetic models of FXS exhibit striking excitatory and inhibitory synapse imbalance, associated with impaired cognitive and social interaction behaviors. Downstream of translation control, a number of specific synaptic proteins regulate excitatory versus inhibitory synaptogenesis, independently or combinatorially, and loss of these proteins is also linked to disrupted neurodevelopment. The current effort is to define the cascade of events linking transcription, translation and the role of specific synaptic proteins in the maintenance of excitatory versus inhibitory synapses during neural circuit formation. This focus includes mechanisms that fine-tune excitation and inhibition during the refinement of functional synaptic circuits, and later modulate this balance throughout life. The use of powerful new genetic models has begun to shed light on the mechanistic bases of excitation/inhibition imbalance for a range of neurodevelopmental disease states.

DYNAMICS OF OPIOID SUBSTITUTION TREATMENTIN DIFFERENT INITIAL SUBSTANCE USER OPIOID DEPENDENT PATIENTS.

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Todadze, Kh; Mosia, S

2016-05-01

Injecting drug user size estimation studies carried out in 2009, 2012 and 2015 revealed growing trends of drug abuse in Georgia:estimated number of people who inject drugs (PWID) have been increased from 40000 and 45000 to 50000. Since Soviet period the most popular injective narcotics have been opioids: home-made opium, heroine, buprenorphine and home-made desomorphine ("Krokodile") replacing each other on the black market. Self-made desomorphine typically contains big amounts of different toxic substances and causes significant somatic disorders, especially skin, bone, blood infections, liver and kidney failure; is highly addictive, associates with frequent injections that enhance injecting-related harm, including the risk of HIV transmission, in comparison with typical opioids. The aim of the study was to determine the effectiveness of opioid substitution treatment (OST) on depression and anxiety in opioid dependent clients with history of different opioid substance use. 104 opioid drug users undergoing OST with intensive psychological counseling have been divided in 5 groups according to the principal opioid drug that was abused during past 6 months before starting treatment: heroine, desomorphine, illicit methadone injectors, illicit buprenorphine injectors, and multiple drug abusers consuming opioids as primary drugs. Level of depression (Beck Depression Inventory), anxiety (Spielberger Anxiety Inventory) as well as clinical symptoms, risky behavior, quality of life (WHO), and other data were measured before starting and after 3, 9, 15, 21 months of treatment. The illegal use of psychotropic-narcotics was checked through random urine-testing 1-2 times per patient per month. In all five groups remarkable decrease of depression and anxiety was observed in comparison with the starting data. Before inclusion desomorphine and poly-drug users had the highest scores of depression and anxiety while buprenorphine users manifested the lowest rate. Improvement of

Effect Of A “No Superuser Opioid Prescription” Policy On ED Visits And Statewide Opioid Prescription

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Zachary P. Kahler

2017-07-01

Full Text Available Introduction: The U.S. opioid epidemic has highlighted the need to identify patients at risk of opioid abuse and overdose. We initiated a novel emergency department- (ED based interventional protocol to transition our superuser patients from the ED to an outpatient chronic pain program. The objective was to evaluate the protocol’s effect on superusers’ annual ED visits. Secondary outcomes included a quantitative evaluation of statewide opioid prescriptions for these patients, unique prescribers of controlled substances, and ancillary testing. Methods: Patients were referred to the program with the following inclusion criteria: ≥ 6 visits per year to the ED; at least one visit identified by the attending physician as primarily driven by opioid-seeking behavior; and a review by a committee comprising ED administration and case management. Patients were referred to a pain management clinic and informed that they would no longer receive opioid prescriptions from visits to the ED for chronic pain complaints. Electronic medical record (EMR alerts notified ED providers of the patient’s referral at subsequent visits. We analyzed one year of data pre- and post-referral. Results: A total of 243 patients had one year of data post-referral for analysis. Median annual ED visits decreased from 14 to 4 (58% decrease, 95% CI [50 to 66]. We also found statistically significant decreases for these patients’ state prescription drug monitoring program (PDMP opioid prescriptions (21 to 13, total unique controlled-substance prescribers (11 to 7, computed tomography imaging (2 to 0, radiographs (5 to 1, electrocardiograms (12 to 4, and labs run (47 to 13. Conclusion: This program and the EMR-based alerts were successful at decreasing local ED visits, annual opioid prescriptions, and hospital resource allocation for this population of patients. There is no evidence that these patients diverted their visits to neighboring EDs after being informed that they

Chronic ethanol consumption in rats produces opioid antinociceptive tolerance through inhibition of mu opioid receptor endocytosis.

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Li He

Full Text Available It is well known that the mu-opioid receptor (MOR plays an important role in the rewarding properties of ethanol. However, it is less clear how chronic ethanol consumption affects MOR signaling. Here, we demonstrate that rats with prolonged voluntary ethanol consumption develop antinociceptive tolerance to opioids. Signaling through the MOR is controlled at many levels, including via the process of endocytosis. Importantly, agonists at the MOR that promote receptor endocytosis, such as the endogenous peptides enkephalin and β-endorphin, show a reduced propensity to promote antinociceptive tolerance than do agonists, like morphine, which do not promote receptor endocytosis. These observations led us to examine whether chronic ethanol consumption produced opioid tolerance by interfering with MOR endocytosis. Indeed, here we show that chronic ethanol consumption inhibits the endocytosis of MOR in response to opioid peptide. This loss of endocytosis was accompanied by a dramatic decrease in G protein coupled receptor kinase 2 (GRK2 protein levels after chronic drinking, suggesting that loss of this component of the trafficking machinery could be a mechanism by which endocytosis is lost. We also found that MOR coupling to G-protein was decreased in ethanol-drinking rats, providing a functional explanation for loss of opioid antinociception. Together, these results suggest that chronic ethanol drinking alters the ability of MOR to endocytose in response to opioid peptides, and consequently, promotes tolerance to the effects of opioids.

The gut-brain interaction in opioid tolerance.

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Akbarali, Hamid I; Dewey, William L

2017-12-01

The prevailing opioid crisis has necessitated the need to understand mechanisms leading to addiction and tolerance, the major contributors to overdose and death and to develop strategies for developing drugs for pain treatment that lack abuse liability and side-effects. Opioids are commonly used for treatment of pain and symptoms of inflammatory bowel disease. The significant effect of opioids in the gut, both acute and chronic, includes persistent constipation and paradoxically may also worsen pain symptoms. Recent work has suggested a significant role of the gastrointestinal microbiome in behavioral responses to opioids, including the development of tolerance to its pain-relieving effects. In this review, we present current concepts of gut-brain interaction in analgesic tolerance to opioids and suggest that peripheral mechanisms emanating from the gut can profoundly affect central control of opioid function. Copyright © 2017 Elsevier Ltd. All rights reserved.

Global Supply and Demand of Opioids for Pain Management.

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Kunnumpurath, Sreekumar; Julien, Natasha; Kodumudi, Gopal; Kunnumpurath, Anamika; Kodumudi, Vijay; Vadivelu, Nalini

2018-04-04

The goal of this review is to evaluate the global supply and demand of opioids used for pain management and discuss how it relates to the utilization of opioids around the world. The purpose of the review is also to determine the factors that contribute to inappropriate pain management. The total global production of opium for opioid manufacturing is enough to supply the growing global demands. However, licit opioids are only consumed by 20% of the world population. Most people throughout the world had no access to opioid analgesics for pain relief in case of need. Opioid misuse and abuse is not only a phenomena plague by the USA but globally across many countries. Many countries have a lack of availability of opioids, contributing factors being strict government regulations limiting access, lack of knowledge of the efficacy of opioid analgesics in treating acute and chronic pain and palliative care, and the stigma that opioids are highly addictive. For the countries in which opioids are readily available and prescribed heavily, diversion, misuse, abuse, and the resurgence of heroin have become problems leading to morbidity and mortality. It is pertinent to find a balance between having opioids accessible to patients in need, with ensuring that opioids are regulated along with other illicit drugs to decrease abuse potential.

Spinal Hb9::Cre-derived excitatory interneurons contribute to rhythm generation in the mouse.

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Caldeira, Vanessa; Dougherty, Kimberly J; Borgius, Lotta; Kiehn, Ole

2017-01-27

Rhythm generating neurons are thought to be ipsilaterally-projecting excitatory neurons in the thoracolumbar mammalian spinal cord. Recently, a subset of Shox2 interneurons (Shox2 non-V2a INs) was found to fulfill these criteria and make up a fraction of the rhythm-generating population. Here we use Hb9::Cre mice to genetically manipulate Hb9::Cre-derived excitatory interneurons (INs) in order to determine the role of these INs in rhythm generation. We demonstrate that this line captures a consistent population of spinal INs which is mixed with respect to neurotransmitter phenotype and progenitor domain, but does not overlap with the Shox2 non-V2a population. We also show that Hb9::Cre-derived INs include the comparatively small medial population of INs which continues to express Hb9 postnatally. When excitatory neurotransmission is selectively blocked by deleting Vglut2 from Hb9::Cre-derived INs, there is no difference in left-right and/or flexor-extensor phasing between these cords and controls, suggesting that excitatory Hb9::Cre-derived INs do not affect pattern generation. In contrast, the frequencies of locomotor activity are significantly lower in cords from Hb9::Cre-Vglut2 Δ/Δ mice than in cords from controls. Collectively, our findings indicate that excitatory Hb9::Cre-derived INs constitute a distinct population of neurons that participates in the rhythm generating kernel for spinal locomotion.

Npas4 regulates excitatory-inhibitory balance within neural circuits through cell-type-specific gene programs.

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Spiegel, Ivo; Mardinly, Alan R; Gabel, Harrison W; Bazinet, Jeremy E; Couch, Cameron H; Tzeng, Christopher P; Harmin, David A; Greenberg, Michael E

2014-05-22

The nervous system adapts to experience by inducing a transcriptional program that controls important aspects of synaptic plasticity. Although the molecular mechanisms of experience-dependent plasticity are well characterized in excitatory neurons, the mechanisms that regulate this process in inhibitory neurons are only poorly understood. Here, we describe a transcriptional program that is induced by neuronal activity in inhibitory neurons. We find that, while neuronal activity induces expression of early-response transcription factors such as Npas4 in both excitatory and inhibitory neurons, Npas4 activates distinct programs of late-response genes in inhibitory and excitatory neurons. These late-response genes differentially regulate synaptic input to these two types of neurons, promoting inhibition onto excitatory neurons while inducing excitation onto inhibitory neurons. These findings suggest that the functional outcomes of activity-induced transcriptional responses are adapted in a cell-type-specific manner to achieve a circuit-wide homeostatic response. Copyright © 2014 Elsevier Inc. All rights reserved.

Intentional intrathecal opioid detoxification in 3 patients: characterization of the intrathecal opioid withdrawal syndrome.

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Jackson, Tracy P; Lonergan, Daniel F; Todd, R David; Martin, Peter R

2013-04-01

Intrathecal (IT) drug delivery systems for patients with chronic non-malignant pain are intended to improve pain and quality of life and reduce side effects of systemic use. A subset of patients may have escalating pain, functional decline, and/or intolerable side effects even as IT opioid doses are increased. Discontinuation of IT medications may represent a viable treatment option but strategies to accomplish this are needed. Three patients with intrathecal drug delivery systems (IDDS), inadequate pain control, and declining functionality underwent abrupt IT opioid cessation. This was accomplished through a standardized protocol with symptom-triggered administration of clonidine and buprenorphine, monitored using the clinical opiate withdrawal scale. Symptoms of IT withdrawal were similar in all patients and included diuresis, agitation, hyperalgesia, mild diarrhea, yawning, and taste and smell aversion. Hypertension and tachycardia were effectively controlled by clonidine administration. Classic symptoms of withdrawal, such as piloerection, chills, severe diarrhea, nausea, vomiting, diaphoresis, myoclonus, and mydriasis, were not noted. At 2 to 3 months follow-up, patients reported decreased, but ongoing pain, with improvements in functional capacity and quality of life. This preliminary work demonstrates the safety of abrupt IT opioid cessation utilizing standardized inpatient withdrawal protocols. To our knowledge, these are among the first reported cases of intentional, controlled IT opioid cessation without initiation of an opioid bridge: self-reported pain scores, functional capacity, and quality of life improved. The IT opioid withdrawal syndrome is characterized based upon our observations and a review of the literature. © 2012 The Authors. Pain Practice © 2012 World Institute of Pain.

Detecting aberrant opioid behavior in the emergency department: a prospective study using the screener and Opioid Assessment for Patients with Pain-Revised (SOAPP®-R), Current Opioid Misuse Measure (COMM)™, and provider gestalt.

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Varney, Shawn M; Perez, Crystal A; Araña, Allyson A; Carey, Katherine R; Ganem, Victoria J; Zarzabal, Lee A; Ramos, Rosemarie G; Bebarta, Vikhyat S

2018-03-03

Emergency department (ED) providers have limited time to evaluate patients at risk for opioid misuse. A validated tool to assess the risk for aberrant opioid behavior may mitigate adverse sequelae associated with prescription opioid misuse. We sought to determine if SOAPP-R, COMM, and provider gestalt were able to identify patients at risk for prescription opioid misuse as determined by pharmacy records at 12 months. We conducted a prospective observational study of adult patients in a high volume US ED. Patients completed the SOAPP-R and COMM, and treating EM providers evaluated patients' opioid misuse risk. We performed variable-centered, person-centered, and hierarchical cluster analyses to determine whether provider gestalt, SOAPP-R, or COMM, or a combination, predicted higher misuse risk. The primary outcome was the number of opioid prescriptions at 12 months according to pharmacy records. For 169 patients (mean age 43 years, 51% female, 73% white), correlation analysis showed a strong relationship between SOAPP-R and COMM with predicting the number of opioid prescriptions dispensed at 12 months. Provider scores estimating opioid misuse were not related to SOAPP-R and only weakly associated with COMM. In our adjusted regression models, provider gestalt and SOAPP-R uniquely predicted opioid prescriptions at 6 and 12 months. Using designated cutoff scores, only SOAPP-R detected a difference in the number of opioid prescriptions. Cluster analysis revealed that provider gestalt, SOAPP-R, and COMM scores jointly predicted opioid prescriptions. Provider gestalt and self-report instruments uniquely predicted the number of opioid prescriptions in ED patients. A combination of gestalt and self-assessment scores can be used to identify at-risk patients who otherwise miss the cutoff scores for SOAPP-R and COMM.

Combined autoradiographic-immunocytochemical analysis of opioid receptors and opioid peptide neuronal systems in brain

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Lewis, M.E.; Khachaturian, H.; Watson, S.J.

1985-01-01

Using adjacent section autoradiography-immunocytochemistry, the distribution of (TH)naloxone binding sites was studied in relation to neuronal systems containing (Leu)enkephalin, dynorphin A, or beta-endorphin immunoreactivity in rat brain. Brain sections from formaldehyde-perfused rats show robust specific binding of (TH)naloxone, the pharmacological (mu-like) properties of which appear unaltered. In contrast, specific binding of the delta ligand (TH)D-Ala2,D-Leu5-enkephalin was virtually totally eliminated as a result of formaldehyde perfusion. Using adjacent section analysis, the authors have noted associations between (TH)naloxone binding sites and one, two, or all three opioid systems in different brain regions; however, in some areas, no apparent relationship could be observed. Within regions, the relationship was complex. The complexity of the association between (TH)naloxone binding sites and the multiple opioid systems, and previous reports of co-localization of mu and kappa receptors in rat brain, are inconsistent with a simple-one-to-one relationship between a given opioid precursor and opioid receptor subtype. Instead, since differential processing of the three precursors gives rise to peptides of varying receptor subtype potencies and selectivities, the multiple peptide-receptor relationships may point to a key role of post-translational processing in determining the physiological consequences of opioid neurotransmission.

Gut Homeostasis, Microbial Dysbiosis, and Opioids.

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Wang, Fuyuan; Roy, Sabita

2017-01-01

Gut homeostasis plays an important role in maintaining animal and human health. The disruption of gut homeostasis has been shown to be associated with multiple diseases. The mutually beneficial relationship between the gut microbiota and the host has been demonstrated to maintain homeostasis of the mucosal immunity and preserve the integrity of the gut epithelial barrier. Currently, rapid progress in the understanding of the host-microbial interaction has redefined toxicological pathology of opioids and their pharmacokinetics. However, it is unclear how opioids modulate the gut microbiome and metabolome. Our study, showing opioid modulation of gut homeostasis in mice, suggests that medical interventions to ameliorate the consequences of drug use/abuse will provide potential therapeutic and diagnostic strategies for opioid-modulated intestinal infections. The study of morphine's modulation of the gut microbiome and metabolome will shed light on the toxicological pathology of opioids and its role in the susceptibility to infectious diseases.

Resisting Prescribed Opioids: A Qualitative Study of Decision Making in Patients Taking Opioids for Chronic Noncancer Pain.

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Paterson, Charlotte; Ledgerwood, Kay; Arnold, Carolyn; Hogg, Malcolm; Xue, Charlie; Zheng, Zhen

2016-04-01

Opioids are increasingly prescribed for chronic noncancer pain across the developed world. Clinical guidelines for management of these patients focus on over-use. However, research into other types of long-term medication indicates that many patients minimize drug use whenever possible. To identify the varying influences on patients' decisions about their use of prescribed opioids and explore whether concepts of resistance and minimization of intake apply to these patients. A multiprofessional team performed a qualitative interview study using the constant-comparative method. Patient's decision making was explored in depth and with a thematic analysis utilizing a published "Model of medicine-taking." A purposive sample of 20 participants drawn from two pain clinics in Melbourne, Australia. The sample was biased toward patients interested in nonmedication pain management options. Patients' needs to obtain relief from severe pain, maintain function, and minimize side effects could lead to under-use as well as over-use of prescribed opioids. In keeping with the published Model of medicine-taking, resistance to taking opioids was a common and important influence on behavior. In the face of severe chronic pain, many participants used a variety of strategies to evaluate, avoid, reduce, self-regulate, and replace opioids. Furthermore, participants perceived a resistance to opioids within the system and among some healthcare professionals. This sometimes adversely affected their adherence. Both patients and doctors exhibit aspects of resistance to the use of prescribed opioids for chronic noncancer pain, suggesting that this shared concern could be the basis of a productive therapeutic alliance to improve communication and shared decision making. Clinical guidelines for opioids use for chronic noncancer pain focus on over-use. Our qualitative interview study found that many patients resisted and minimized the use of opioids. Using a published "Model of medicine-taking," we

Pleiotropic opioid regulation of spinal endomorphin 2 release and its adaptations to opioid withdrawal are sexually dimorphic.

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Chakrabarti, Sumita; Liu, Nai-Jiang; Zadina, James E; Sharma, Tarak; Gintzler, Alan R

2012-01-01

We studied adaptations to acute precipitated opioid withdrawal of spinal μ-opioid receptor (MOR)-coupled regulation of the release of endomorphin 2 (EM2). The release of this highly MOR-selective endogenous opioid from opioid-naive spinal tissue of male rats is subjected to MOR-coupled positive as well as negative modulation via cholera toxin-sensitive G(s) and pertussis toxin-sensitive G(i)/G(o), respectively. The net effect of this concomitant bidirectional modulation is inhibitory. MOR-coupled pleiotropic regulation of EM2 release is retained in opioid-withdrawn spinal tissue of male rats, but the balance of MOR-coupled inhibitory and facilitatory regulation shifted such that facilitatory regulation predominates. Augmented coupling of MOR to G(s) is causally associated with this change. Strikingly, pleiotropic characteristics of MOR-coupled regulation of spinal EM2 release and adaptations thereof to opioid withdrawal are male-specific. In females, MOR-coupled regulation of EM2 release from opioid-naive and -withdrawn spinal tissue does not have a significant G(s)-coupled facilitatory component, and MOR-coupled inhibition of EM2 release persists unabated in withdrawn preparations. The male-specific adaptations to chronic morphine that shift the relative predominance of opposing dual G protein-coupled MOR pathways provides a mechanism for mitigating inhibitory MOR signaling without losing MOR-coupled feedback regulation. These adaptations enable using endogenous EM2 as a substitute for morphine that had been precipitously removed. The sexually dimorphic functionality and regulation of spinal EM2/MOR-coupled signaling suggest the clinical utility of using sex-specific treatments for addiction that harness the activity of endogenous opioids.

Secular trends in opioid prescribing in the USA

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Pezalla EJ

2017-02-01

Full Text Available Edmund J Pezalla,1 David Rosen,2 Jennifer G Erensen,2 J David Haddox,2,3 Tracy J Mayne2 1Bioconsult, LLC, Wethersfield, 2Purdue Pharma L.P., Stamford, CT, 3Public Health and Community Medicine, Tufts University School of Medicine, Boston, MA, USA Abstract: Opioid abuse and misuse in the USA is a public health crisis. The use of prescription opioid analgesics increased substantially from 2002 through 2010, then plateaued and began to decrease in 2011. This study examined prescriptions of branded and generic immediate- and extended-release opioid analgesics from 1992 to 2016. This was juxtaposed against state and federal policies designed to decrease overutilization and abuse, as well as the launch of new opioid products, including opioids with abuse-deterrent properties (OADPs. The data indicate that these health policies, including the utilization and reimbursement of OADPs, have coincided with decreased opioid utilization. The hypothesis that OADPs will paradoxically increase opioid prescribing is not supported. Keywords: OADP, prescription, utilization trends, legislation, opioids

The relative potency of inverse opioid agonists and a neutral opioid antagonist in precipitated withdrawal and antagonism of analgesia and toxicity.

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Sirohi, Sunil; Dighe, Shveta V; Madia, Priyanka A; Yoburn, Byron C

2009-08-01

Opioid antagonists can be classified as inverse agonists and neutral antagonists. In the opioid-dependent state, neutral antagonists are significantly less potent in precipitating withdrawal than inverse agonists. Consequently, neutral opioid antagonists may offer advantages over inverse agonists in the management of opioid overdose. In this study, the relative potency of three opioid antagonists to block opioid analgesia and toxicity and precipitate withdrawal was examined. First, the potency of two opioid inverse agonists (naltrexone and naloxone) and a neutral antagonist (6beta-naltrexol) to antagonize fentanyl-induced analgesia and lethality was determined. The order of potency to block analgesia was naltrexone > naloxone > 6beta-naltrexol (17, 4, 1), which was similar to that to block lethality (13, 2, 1). Next, the antagonists were compared using withdrawal jumping in fentanyl-dependent mice. The order of potency to precipitate withdrawal jumping was naltrexone > naloxone 6beta-naltrexol (1107, 415, 1). The relative potencies to precipitate withdrawal for the inverse agonists compared with the neutral antagonist were dramatically different from that for antagonism of analgesia and lethality. Finally, the effect of 6beta-naltrexol pretreatment on naloxone-precipitated jumping was determined in morphine and fentanyl-dependent mice. 6beta-Naltrexol pretreatment decreased naloxone precipitated withdrawal, indicating that 6beta-naltrexol is a neutral antagonist. These data demonstrate that inverse agonists and neutral antagonists have generally comparable potencies to block opioid analgesia and lethality, whereas the neutral opioid antagonist is substantially less potent in precipitating opioid withdrawal. These results support suggestions that neutral antagonists may have advantages over inverse agonists in the management of opioid overdose.

Health-Related Quality of Life among Chronic Opioid Users, Nonchronic Opioid Users, and Nonopioid Users with Chronic Noncancer Pain.

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Hayes, Corey J; Li, Xiaocong; Li, Chenghui; Shah, Anuj; Kathe, Niranjan; Bhandari, Naleen Raj; Payakachat, Nalin

2018-02-25

Evaluate the association between opioid therapy and health-related quality of life (HRQoL) in participants with chronic, noncancer pain (CNCP). Medical Expenditure Panel Survey Longitudinal, Medical Conditions, and Prescription Files. Using a retrospective cohort study design, the Mental Health Component (MCS12) and Physical Health Component (PCS12) scores of the Short Form-12 Version 2 were assessed to measure mental and physical HRQoL. Chronic, noncancer pain participants were classified as chronic, nonchronic, and nonopioid users. One-to-one propensity score matching was employed to match chronic opioid users to nonchronic opioid users plus nonchronic opioid users and chronic opioid users to nonopioid users. A total of 5,876 participants were identified. After matching, PCS12 was not significantly different between nonchronic versus nonopioid users (LSM Diff = -0.98, 95% CI: -2.07, 0.10), chronic versus nonopioid users (LSM Diff = -2.24, 95% CI: -4.58, 0.10), or chronic versus nonchronic opioid users (LSM Diff = -2.23, 95% CI: -4.53, 0.05). Similarly, MCS12 was not significantly different between nonchronic versus nonopioid users (LSM Diff = 0.76, 95% CI: -0.46, 1.98), chronic versus nonopioid users (LSM Diff = 1.08, 95% CI: -1.26, 3.42), or chronic versus nonchronic opioid users (LSM Diff = -0.57, 95% CI: -2.90, 1.77). Clinicians should evaluate opioid use in participants with CNCP as opioid use is not correlated with better HRQoL. © Health Research and Educational Trust.

Tolerance to Non-Opioid Analgesics is Opioid Sensitive in the Nucleus Raphe Magnus.

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Tsagareli, Merab G; Nozadze, Ivliane; Tsiklauri, Nana; Gurtskaia, Gulnaz

2011-01-01

Repeated injection of opioid analgesics can lead to a progressive loss of effect. This phenomenon is known as tolerance. Several lines of investigations have shown that systemic, intraperitoneal administration or the microinjection of non-opioid analgesics, non-steroidal anti-inflammatory drugs (NSAIDs) into the midbrain periaqueductal gray matter induces antinociception with some effects of tolerance. Our recent study has revealed that microinjection of three drugs analgin, ketorolac, and xefocam into the central nucleus of amygdala produce tolerance to them and cross-tolerance to morphine. Here we report that repeated administrations of these NSAIDs into the nucleus raphe magnus (NRM) in the following 4 days result in progressively less antinociception compare to the saline control, i.e., tolerance develops to these drugs in male rats. Special control experiments showed that post-treatment with the μ-opioid antagonist naloxone into the NRM significantly decreased antinociceptive effects of NSAIDs on the first day of testing in the tail-flick (TF) reflex and hot plate (HP) latency tests. On the second day, naloxone generally had trend effects in both TF and HP tests and impeded the development of tolerance to the antinociceptive effect of non-opioid analgesics. These findings strongly support the suggestion of endogenous opioid involvement in NSAIDs antinociception and tolerance in the descending pain-control system. Moreover, repeated injections of NSAIDs progressively lead to tolerance to them, cross-tolerance to morphine, and the risk of a withdrawal syndrome. Therefore, these results are important for human medicine too.

Tolerance and withdrawal from prolonged opioid use in critically ill children.

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Anand, Kanwaljeet J S; Willson, Douglas F; Berger, John; Harrison, Rick; Meert, Kathleen L; Zimmerman, Jerry; Carcillo, Joseph; Newth, Christopher J L; Prodhan, Parthak; Dean, J Michael; Nicholson, Carol

2010-05-01

After prolonged opioid exposure, children develop opioid-induced hyperalgesia, tolerance, and withdrawal. Strategies for prevention and management should be based on the mechanisms of opioid tolerance and withdrawal. Relevant manuscripts published in the English language were searched in Medline by using search terms "opioid," "opiate," "sedation," "analgesia," "child," "infant-newborn," "tolerance," "dependency," "withdrawal," "analgesic," "receptor," and "individual opioid drugs." Clinical and preclinical studies were reviewed for data synthesis. Mechanisms of opioid-induced hyperalgesia and tolerance suggest important drug- and patient-related risk factors that lead to tolerance and withdrawal. Opioid tolerance occurs earlier in the younger age groups, develops commonly during critical illness, and results more frequently from prolonged intravenous infusions of short-acting opioids. Treatment options include slowly tapering opioid doses, switching to longer-acting opioids, or specifically treating the symptoms of opioid withdrawal. Novel therapies may also include blocking the mechanisms of opioid tolerance, which would enhance the safety and effectiveness of opioid analgesia. Opioid tolerance and withdrawal occur frequently in critically ill children. Novel insights into opioid receptor physiology and cellular biochemical changes will inform scientific approaches for the use of opioid analgesia and the prevention of opioid tolerance and withdrawal.

Isobolographic analysis of the opioid-opioid interactions in a tonic and a phasic mouse model of induced nociceptive pain.

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

2014-07-15

Opioids have been used for the management of pain and coadministration of two opioids may induce synergism. In a model of tonic pain, the acetic acid writhing test and in a phasic model, the hot plate, the antinociceptive interaction between fentanyl, methadone, morphine, and tramadol was evaluated. The potency of opioids in the writhing test compared to the hot plate assay was from 2.5 (fentanyl) to 15.5 (morphine) times, respectively. The ED50 was used in a fixed ratio for each of the six pairs of opioid combinations, which, resulted in a synergistic antinociception except for methadone/tramadol and fentanyl/tramadol which were additive, in the hot plate. The opioid antagonists naltrexone, naltrindole and nor-binaltorphimine, suggests that the synergism of morphine combinations are due to the activation of MOR subtypes with partially contribution of DOR and KOR, however fentanyl and methadone combinations are partially due to the activation of MOR and DOR subtypes and KOR lack of participation. The antinociceptive effects of tramadol combinations, are partially due to the activation of MOR, DOR and KOR opioid subtypes. These results suggets that effectiveness and magnitude of the interactions between opioids are dependent on pain stimulus intensity.

Schaffer collateral inputs to CA1 excitatory and inhibitory neurons follow different connectivity rules.

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Kwon, Osung; Feng, Linqing; Druckmann, Shaul; Kim, Jinhyun

2018-05-04

Neural circuits, governed by a complex interplay between excitatory and inhibitory neurons, are the substrate for information processing, and the organization of synaptic connectivity in neural network is an important determinant of circuit function. Here, we analyzed the fine structure of connectivity in hippocampal CA1 excitatory and inhibitory neurons innervated by Schaffer collaterals (SCs) using mGRASP in male mice. Our previous study revealed spatially structured synaptic connectivity between CA3-CA1 pyramidal cells (PCs). Surprisingly, parvalbumin-positive interneurons (PVs) showed a significantly more random pattern spatial structure. Notably, application of Peters' Rule for synapse prediction by random overlap between axons and dendrites enhanced structured connectivity in PCs, but, by contrast, made the connectivity pattern in PVs more random. In addition, PCs in a deep sublayer of striatum pyramidale appeared more highly structured than PCs in superficial layers, and little or no sublayer specificity was found in PVs. Our results show that CA1 excitatory PCs and inhibitory PVs innervated by the same SC inputs follow different connectivity rules. The different organizations of fine scale structured connectivity in hippocampal excitatory and inhibitory neurons provide important insights into the development and functions of neural networks. SIGNIFICANCE STATEMENT Understanding how neural circuits generate behavior is one of the central goals of neuroscience. An important component of this endeavor is the mapping of fine-scale connection patterns that underlie, and help us infer, signal processing in the brain. Here, using our recently developed synapse detection technology (mGRASP and neuTube), we provide detailed profiles of synaptic connectivity in excitatory (CA1 pyramidal) and inhibitory (CA1 parvalbumin-positive) neurons innervated by the same presynaptic inputs (CA3 Schaffer collaterals). Our results reveal that these two types of CA1 neurons follow

Observational study to calculate addictive risk to opioids: a validation study of a predictive algorithm to evaluate opioid use disorder

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Brenton A

2017-05-01

Full Text Available Ashley Brenton,1 Steven Richeimer,2,3 Maneesh Sharma,4 Chee Lee,1 Svetlana Kantorovich,1 John Blanchard,1 Brian Meshkin1 1Proove Biosciences, Irvine, CA, 2Keck school of Medicine, University of Southern California, Los Angeles, CA, 3Departments of Anesthesiology and Psychiatry, University of Southern California, Los Angeles, CA, 4Interventional Pain Institute, Baltimore, MD, USA Background: Opioid abuse in chronic pain patients is a major public health issue, with rapidly increasing addiction rates and deaths from unintentional overdose more than quadrupling since 1999. Purpose: This study seeks to determine the predictability of aberrant behavior to opioids using a comprehensive scoring algorithm incorporating phenotypic risk factors and neuroscience-associated single-nucleotide polymorphisms (SNPs. Patients and methods: The Proove Opioid Risk (POR algorithm determines the predictability of aberrant behavior to opioids using a comprehensive scoring algorithm incorporating phenotypic risk factors and neuroscience-associated SNPs. In a validation study with 258 subjects with diagnosed opioid use disorder (OUD and 650 controls who reported using opioids, the POR successfully categorized patients at high and moderate risks of opioid misuse or abuse with 95.7% sensitivity. Regardless of changes in the prevalence of opioid misuse or abuse, the sensitivity of POR remained >95%. Conclusion: The POR correctly stratifies patients into low-, moderate-, and high-risk categories to appropriately identify patients at need for additional guidance, monitoring, or treatment changes. Keywords: opioid use disorder, addiction, personalized medicine, pharmacogenetics, genetic testing, predictive algorithm

Comparison of the risks of shopping behavior and opioid abuse between tapentadol and oxycodone and association of shopping behavior and opioid abuse.

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Cepeda, M Soledad; Fife, Daniel; Kihm, Mary A; Mastrogiovanni, Greg; Yuan, Yingli

2014-12-01

This study compared the risks of opioid shopping behavior and opioid abuse between tapentadol immediate release and oxycodone immediate release and, to validate the definition of shopping, examined the association between opioid shopping and opioid abuse further. This retrospective cohort study using linked dispensing and diagnosis databases followed opioid-naive patients for development of shopping behavior and/or opioid abuse during 1 year after initial exposure to tapentadol or oxycodone. Shopping was defined by having overlapping opioid prescriptions from >1 prescriber filled at ≥3 pharmacies; abuse by having International Classification of Diseases, 9th revision diagnoses reflecting opioid abuse, addiction, or dependence. To determine their association, we cross-tabulated shopping and opioid abuse and calculated odds ratios. Risks of developing each outcome were estimated using logistic regression. Among 277,401 participants initiating opioid use with tapentadol (39,524) or oxycodone (237,877), 0.6% developed shopping behavior, 0.75% developed abuse. Higher proportions of patients in the oxycodone group developed shopping behavior and abuse than in the tapentadol group (shopping: adjusted odds ratio [95% confidence interval], 0.45 [0.36-0.55]; abuse: 0.44 [0.37-0.54]). Shopping behavior and abuse were associated; of those with shopping behavior, 6.5% had abuse. Age (18 to 64 y), sex (male), prior benzodiazepine use, paying cash, and history (mood disorders, abuse of nonopioid medications, and back pain) were risk factors for developing either outcome. Shopping behavior and abuse measure complementary, but associated, constructs, which further validates the current definition of shopping. The risk of developing either is lower among patients who initiate opioid use with tapentadol than those who initiate opioid use with oxycodone.

Spinal Hb9::Cre-derived excitatory interneurons contribute to rhythm generation in the mouse

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Caldeira, Vanessa; Dougherty, Kimberly J.; Borgius, Lotta

2017-01-01

Rhythm generating neurons are thought to be ipsilaterally-projecting excitatory neurons in the thoracolumbar mammalian spinal cord. Recently, a subset of Shox2 interneurons (Shox2 non-V2a INs) was found to fulfill these criteria and make up a fraction of the rhythm-generating population. Here we...... than in cords from controls. Collectively, our findings indicate that excitatory Hb9::Cre-derived INs constitute a distinct population of neurons that participates in the rhythm generating kernel for spinal locomotion....... use Hb9::Cre mice to genetically manipulate Hb9::Cre-derived excitatory interneurons (INs) in order to determine the role of these INs in rhythm generation. We demonstrate that this line captures a consistent population of spinal INs which is mixed with respect to neurotransmitter phenotype...

Long-term evaluation of opioid treatment in fibromyalgia.

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Peng, Xiaomei; Robinson, Rebecca L; Mease, Philip; Kroenke, Kurt; Williams, David A; Chen, Yi; Faries, Douglas; Wohlreich, Madelaine; McCarberg, Bill; Hann, Danette

2015-01-01

In a 12-month observational study, we evaluated the effect of opioid use on the outcomes in 1700 adult patients with fibromyalgia. Data were evaluated using propensity score matching after patients were divided into cohorts based on their baseline medication use: (1) taking an opioid (concurrent use of tramadol was permitted); (2) taking tramadol (but no opioids); and (3) not taking opioids or tramadol. Changes in outcomes were assessed using the Brief Pain Inventory for severity and pain-related interference (BPI-S, BPI-I), Fibromyalgia Impact Questionnaire (FIQ), Patient Health Questionnaire for depression (PHQ-8), Insomnia Severity Index (ISI), Sheehan Disability Scale (SDS), 7-item Generalized Anxiety Disorder Scale (GAD-7), and economic factors. Time-to-opioid or tramadol discontinuation was analyzed using Kaplan-Meier survival analyses. Compared with the opioid cohort, the nonopioid cohort demonstrated significantly greater reductions (PFIQ, PHQ-8, SDS, and ISI; the tramadol cohort compared with the opioid group showed greater reductions on FIQ and ISI. Reductions in BPI-S and GAD-7 did not differ significantly among cohorts. Compared with the opioid cohort, patients in the tramadol cohort had fewer outpatient visits to health care providers. Few significant differences were found between the tramadol and nonopioid cohorts across outcomes. Although pain severity was reduced over time in all cohorts, opioid users showed less improvement in pain-related interference with daily living, functioning, depression, and insomnia. Overall, the findings show little support for the long-term use of opioid medications in patients with fibromyalgia given the poorer outcomes across multiple assessment domains associated with this cohort.

Reduction of opioid withdrawal and potentiation of acute opioid analgesia by systemic AV411 (ibudilast).

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Hutchinson, Mark R; Lewis, Susannah S; Coats, Benjamen D; Skyba, David A; Crysdale, Nicole Y; Berkelhammer, Debra L; Brzeski, Anita; Northcutt, Alexis; Vietz, Christine M; Judd, Charles M; Maier, Steven F; Watkins, Linda R; Johnson, Kirk W

2009-02-01

Morphine-induced glial proinflammatory responses have been documented to contribute to tolerance to opioid analgesia. Here, we examined whether drugs previously shown to suppress glial proinflammatory responses can alter other clinically relevant opioid effects; namely, withdrawal or acute analgesia. AV411 (ibudilast) and minocycline, drugs with distinct mechanisms of action that result in attenuation of glial proinflammatory responses, each reduced naloxone-precipitated withdrawal. Analysis of brain nuclei associated with opioid withdrawal revealed that morphine altered expression of glial activation markers, cytokines, chemokines, and a neurotrophic factor. AV411 attenuated many of these morphine-induced effects. AV411 also protected against spontaneous withdrawal-induced hyperactivity and weight loss recorded across a 12-day timecourse. Notably, in the spontaneous withdrawal study, AV411 treatment was delayed relative to the start of the morphine regimen so to also test whether AV411 could still be effective in the face of established morphine dependence, which it was. AV411 did not simply attenuate all opioid effects, as co-administering AV411 with morphine or oxycodone caused three-to-five-fold increases in acute analgesic potency, as revealed by leftward shifts in the analgesic dose response curves. Timecourse analyses revealed that plasma morphine levels were not altered by AV411, suggestive that potentiated analgesia was not simply due to prolongation of morphine exposure or increased plasma concentrations. These data support and extend similar potentiation of acute opioid analgesia by minocycline, again providing converging lines of evidence of glial involvement. Hence, suppression of glial proinflammatory responses can significantly reduce opioid withdrawal, while improving analgesia.

Pain management and opioid risk mitigation in the military.

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Sharpe Potter, Jennifer; Bebarta, Vikhyat S; Marino, Elise N; Ramos, Rosemarie G; Turner, Barbara J

2014-05-01

Opioid analgesics misuse is a significant military health concern recognized as a priority issue by military leadership. Opioids are among those most commonly prescribed medications in the military for pain management. The military has implemented opioid risk mitigation strategies, including the Sole Provider Program and the Controlled Drug Management Analysis and Reporting Tool, which are used to identify and monitor for risk and misuse. However, there are substantial opportunities to build on these existing systems to better ensure safer opioid prescribing and monitor for misuse. Opioid risk mitigation strategies implemented by the civilian sector include establishing clinical guidelines for opioid prescribing and prescription monitoring programs. These strategies may help to inform opioid risk mitigation in the military health system. Reducing the risk of opioid misuse and improving quality of care for our Warfighters is necessary. This must be done through evidence-based approaches with an investment in research to improve patient care and prevent opioid misuse as well as its sequelae. Reprint & Copyright © 2014 Association of Military Surgeons of the U.S.

A case of rhabdomyolysis associated with severe opioid withdrawal.

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Gangahar, Deepali

2015-08-01

While the risk of opioid overdose is widely accepted, the dangers of opioid withdrawal are far less clearly defined. The purpose of this publication is to provide evidence against the erroneous clinical dictum that opioid withdrawal is never life-threatening. This case report (N = 1) illustrates an unfortunate, common scenario of a man abusing prescription opioids and heroin. His attempt at self-detoxification with buprenorphine-naloxone resulted in life-threatening opioid withdrawal. A detailed account of each day of his withdrawal period was documented by patient and family report and review of all medical records. The patient was contacted three months after hospitalization to verify information and determine progress in treatment and abstinence from drugs and alcohol. A review of the literature was completed on severe cases of precipitated and spontaneous opioid withdrawal followed by a discussion of the significance as it relates to this case. Given the widespread use of prescription opioids and opioid maintenance treatment, physicians should be aware of the complications of acute opioid withdrawal and should be equipped to treat these complications. © American Academy of Addiction Psychiatry.

Prescription opioid abuse, pain and addiction: clinical issues and implications.

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Ling, Walter; Mooney, Larissa; Hillhouse, Maureen

2011-05-01

Prescription opioid misuse in the USA has increased over threefold since 1990 to epidemic proportions, with substantial increases in prescription opioid use also reported in other countries, such as Australia and New Zealand. The broad availability of prescription pain medications, coupled with public misconceptions about their safety and addictive potential, have contributed to the recent surge in non-medical use of prescription opioids and corresponding increases in treatment admissions for problems related to opioid misuse. Given competing pressures faced by physicians to both diagnose and treat pain syndromes and identify individuals at risk for addictive disorders, the use of opioids in the treatment of pain poses a significant clinical challenge. This paper reviews the interaction between pain and opioid addiction with a focus on clinical management issues, including risk factors for opioid dependence in patients with chronic pain and the use of assessment tools to identify and monitor at-risk individuals. Treatment options for opioid dependence and pain are reviewed, including the use of the partial µ agonist buprenorphine in the management of concurrent pain and opioid addiction. Physicians should strive to find a reasonable balance between minimising potential adverse effects of opioid medications without diminishing legitimate access to opioids for analgesia. The article discusses the need to identify methods for minimising risks and negative consequences associated with opioid analgesics and poses research directions, including the development of abuse-deterrent opioid formulations, genetic risk factors for opioid dependence and opioid-induced hyperalgesia as a potential target for medication therapy. © 2011 Australasian Professional Society on Alcohol and other Drugs.

Newer approaches to opioid detoxification

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Siddharth Sarkar

2012-01-01

Full Text Available Opioid use disorders present with distressing withdrawal symptoms at the time of detoxification. The pharmacological agents and methods currently in use for detoxification mainly include buprenorphine, methadone, and clonidine. Many other pharmacological agents have been tried for opioid detoxification. This review takes a look at the newer pharmacological options, both opioid agonists and non-agonist medications that have been utilized for detoxification. Peer reviewed articles were identified using PubMed and PsychInfo databases. The keywords included for the search were a combination of ′opioid′ and ′detoxification′ and their synonyms. All the articles published in the last 10 years were screened for. Relevant data was extracted from identified studies. Many newer pharmacological agents have been tried in detoxification of opioids. However, the quest for a safe, efficacious, cost-effective pharmacological option which requires minimal monitoring still continues. The role of non-pharmacological measures and alternative medicine needs further evaluation.

Towards safer use of opioids.

LENUS (Irish Health Repository)

Carson, R W R

2009-09-01

The main aim of our work was to improve the safety of opioid use in our institution, an acute generalhospital with 620 beds. Initially, all reported opioid errors from 2001 - 2006 were audited. The findings directed a range of multidisciplinary staff educational inputs to improve opioid prescribing and administration practice, and encourage drug error reporting. 448 drug errors were reported, of which 54 (12%) involved opioids; of these, 43 (79%) involved codeine, morphine or oxycodone. 31 of the errors (57%) were associated with administration, followed by 12 (22%) with dispensing and 11 (20%) with prescribing. There were 2 reports of definite patient harm. A subsequent audit examined a 17-month period following the introduction of the above teaching: 17 errors were noted, of which 14 (83%) involved codeine, morphine or oxycodone. Again, drug administration was most error-prone, comprising 11 (65%) of reports. However, just 2 (12%) of the reported errors now involved prescribing, which was a reduction.

Endogenous opioids encode relative taste preference.

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Taha, Sharif A; Norsted, Ebba; Lee, Lillian S; Lang, Penelope D; Lee, Brian S; Woolley, Joshua D; Fields, Howard L

2006-08-01

Endogenous opioid signaling contributes to the neural control of food intake. Opioid signaling is thought to regulate palatability, the reward value of a food item as determined by orosensory cues such as taste and texture. The reward value of a food reflects not only these sensory properties but also the relative value of competing food choices. In the present experiment, we used a consummatory contrast paradigm to manipulate the relative value of a sucrose solution for two groups of rats. Systemic injection of the nonspecific opioid antagonist naltrexone suppressed sucrose intake; for both groups, however, this suppression was selective, occurring only for the relatively more valuable sucrose solution. Our results indicate that endogenous opioid signaling contributes to the encoding of relative reward value.

Dextromethorphan differentially affects opioid antinociception in rats

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Chen, Shiou-Lan; Huang, Eagle Yi-Kung; Chow, Lok-Hi; Tao, Pao-Luh

2005-01-01

Opioid drugs such as morphine and meperidine are widely used in clinical pain management, although they can cause some adverse effects. A number of studies indicate that N-methyl-D-aspartate (NMDA) receptors may play a role in the mechanism of morphine analgesia, tolerance and dependence. Being an antitussive with NMDA antagonist properties, dextromethorphan (DM) may have some therapeutic benefits when coadministered with morphine. In the present study, we investigated the effects of DM on the antinociceptive effects of different opioids. We also investigated the possible pharmacokinetic mechanisms involved. The antinociceptive effects of the μ-opioid receptor agonists morphine (5 mg kg−1, s.c.), meperidine (25 mg kg−1, s.c.) and codeine (25 mg kg−1, s.c.), and the κ-opioid agonists nalbuphine (8 mg kg−1, s.c.) and U-50,488H (20 mg kg−1, s.c.) were studied using the tail-flick test in male Sprague–Dawley rats. Coadministration of DM (20 mg kg−1, i.p.) with these opioids was also performed and investigated. The pharmacokinetic effects of DM on morphine and codeine were examined, and the free concentration of morphine or codeine in serum was determined by HPLC. It was found that DM potentiated the antinociceptive effects of some μ-opioid agonists but not codeine or κ-opioid agonists in rats. DM potentiated morphine's antinociceptive effect, and acutely increased the serum concentration of morphine. In contrast, DM attenuated the antinociceptive effect of codeine and decreased the serum concentration of its active metabolite (morphine). The pharmacokinetic interactions between DM and opioids may partially explain the differential effects of DM on the antinociception caused by opioids. PMID:15655510

PSYCHIATRIC COMORBIDITY IN PATIENTS WITH OPIOID DEPENDENCE

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Shihab Kattukulathil

2018-02-01

Full Text Available BACKGROUND Opioid dependence is a major public health problem in Kerala. Presence of psychiatric disorder among opioid dependent patients worsens the scenario. To date no attempts have been made to analyse the magnitude and pattern of comorbid psychiatric disorders in the state. MATERIALS AND METHODS We assessed 30 patients with ICD-10 diagnosis of opioid dependence syndrome for the presence of comorbid psychiatric disorders using structured clinical interview for DSM IV Axis 1 disorder (SCID-1. Patients with opioid withdrawal state, delirium and acute medical emergencies were excluded. RESULTS 56.7% of our subjects had a comorbid psychiatric disorder. Major depressive disorder was the most common one (n=7, 23.3%. Prevalence of other disorders were generalised anxiety disorder (n=6, 20%, bipolar affective disorder (n=3, 10% and schizophrenia (n=1, 3.3%. CONCLUSION Comorbid Psychiatric disorders are highly prevalent in opioid dependence. There is a need for further large sample studies in the areas of comorbidities and in the integrated strategies for the identification and management of both opioid dependence and comorbid psychiatric disorders.

Variants of opioid system genes are associated with non-dependent opioid use and heroin dependence

NARCIS (Netherlands)

Randesi, Matthew; van den Brink, Wim; Levran, Orna; Blanken, Peter; Butelman, Eduardo R; Yuferov, Vadim; da Rosa, Joel Correa; Ott, Jurg; van Ree, Jan M; Kreek, Mary Jeanne

2016-01-01

BACKGROUND: Heroin addiction is a chronic, relapsing brain disease. Genetic factors are involved in the development of drug addiction. The aim of this study was to determine whether specific variants in genes of the opioid system are associated with non-dependent opioid use and heroin dependence.

Variants of opioid system genes are associated with non-dependent opioid use and heroin dependence

NARCIS (Netherlands)

Randesi, Matthew; van den Brink, Wim; Levran, Orna; Blanken, Peter; Butelman, Eduardo R.; Yuferov, Vadim; da Rosa, Joel Correa; Ott, Jurg; van Ree, Jan M.; Kreek, Mary Jeanne

2016-01-01

Heroin addiction is a chronic, relapsing brain disease. Genetic factors are involved in the development of drug addiction. The aim of this study was to determine whether specific variants in genes of the opioid system are associated with non-dependent opioid use and heroin dependence. Genetic

Opioid Prescriptions by Specialty in Ohio, 2010-2014.

Science.gov (United States)

Weiner, Scott G; Baker, Olesya; Rodgers, Ann F; Garner, Chad; Nelson, Lewis S; Kreiner, Peter W; Schuur, Jeremiah D

2018-05-01

The current US opioid epidemic is attributed to the large volume of prescribed opioids. This study analyzed the contribution of different medical specialties to overall opioids by evaluating the pill counts and morphine milligram equivalents (MMEs) of opioid prescriptions, stratified by provider specialty, and determined temporal trends. This was an analysis of the Ohio prescription drug monitoring program database, which captures scheduled medication prescriptions filled in the state as well as prescriber specialty. We extracted prescriptions for pill versions of opioids written in the calendar years 2010 to 2014. The main outcomes were the number of filled prescriptions, pill counts, MMEs, and extended-released opioids written by physicians in each specialty, and annual prescribing trends. There were 56,873,719 prescriptions for the studied opioids dispensed, for which 41,959,581 (73.8%) had prescriber specialty type available. Mean number of pills per prescription and MMEs were highest for physical medicine/rehabilitation (PM&R; 91.2 pills, 1,532 mg, N = 1,680,579), anesthesiology/pain (89.3 pills, 1,484 mg, N = 3,261,449), hematology/oncology (88.2 pills, 1,534 mg, N = 516,596), and neurology (84.4 pills, 1,230 mg, N = 573,389). Family medicine (21.8%) and internal medicine (17.6%) wrote the most opioid prescriptions overall. Time trends in the average number of pills and MMEs per prescription also varied depending on specialty. The numbers of pills and MMEs per opioid prescription vary markedly by prescriber specialty, as do trends in prescribing characteristics. Pill count and MME values define each specialty's contribution to overall opioid prescribing more accurately than the number of prescriptions alone.

Possible Opioid Shopping and its Correlates.

Science.gov (United States)

Walker, Alexander M; Weatherby, Lisa B; Cepeda, M Soledad; Bradford, Daniel; Yuan, Yingli

2017-11-01

We created an operational definition of possible opioid shopping in US commercial health insurance data and examined its correlates. The population consisted of 264,204 treatment courses in persons with a fill for an opioid or diuretic prescription in 2012 and a second within 18 months. We examined counts of prescribers and pharmacies and the numbers of fills and overlaps for ability to discriminate courses of opioids from diuretics, which were a negative control. The most discriminatory measure, indicating possible shopping behavior, was cross-tabulated against other prescriptions filled and diagnoses as found in insurance claims. The associations between claims characteristics and shopping behavior were assessed in a logistic regression. A definition that classified possible "moderate" or "extensive" shopping when a person obtained drug through at least 3 practices and at least 3 pharmacies over 18 months was highly discriminatory between opioid and diuretic treatment. Overlaps between fills and number of fills did not improve the discrimination. Data from insurance claims strongly predicted moderate-to-extensive levels of possible shopping (c=0.82). Prominent among 20 significant predictors were: state of residence; amount of opioid dispensed; self-payment; use of nonspecialist prescribers; high use of anxiolytics, hypnotics, psychostimulants, and antipsychotics; and use of both immediate release and extended-release or long-acting opioids. The use of ≥3 prescribing practices and ≥3 dispensing pharmacies over 18 months sharply discriminated courses of opioid treatment from courses of diuretics. This pattern of fills was additionally associated with the numbers of nonspecialist and self-paid fills, the total morphine milligram equivalents dispensed, and heavier use of drugs for anxiety, sleep, attention, and psychosis.

Opioid withdrawal signs and symptoms in children: frequency and determinants.

Science.gov (United States)

Fisher, Deborah; Grap, Mary Jo; Younger, Janet B; Ameringer, Suzanne; Elswick, R K

2013-01-01

The purpose of this study was to, in a pediatric population, describe the frequency of opioid withdrawal signs and symptoms and to identify factors associated with these opioid withdrawal signs and symptoms. Opioids are used routinely in the pediatric intensive care population for analgesia, sedation, blunting of physiologic responses to stress, and safety. In children, physical dependence may occur in as little as 2-3 days of continuous opioid therapy. Once the child no longer needs the opioid, the medications are reduced over time. A prospective, descriptive study was conducted. The sample of 26 was drawn from all patients, ages 2 weeks to 21 years admitted to the Children's Hospital of Richmond pediatric intensive care unit (PICU) and who have received continuous infusion or scheduled opioids for at least 5 days. Data collected included: opioid withdrawal score (WAT-1), opioid taper rate (total dose of opioid per day in morphine equivalents per kilogram [MEK]), pretaper peak MEK, pretaper cumulative MEK, number of days of opioid exposure prior to taper, and age. Out of 26 enrolled participants, only 9 (45%) had opioid withdrawal on any given day. In addition, there was limited variability in WAT-1 scores. The most common symptoms notes were diarrhea, vomit, sweat, and fever. For optimal opioid withdrawal assessments, clinicians should use a validated instrument such as the WAT-1 to measure for signs and symptoms of opioid withdrawal. Further research is indicated to examine risk factors for opioid withdrawal in children. Copyright © 2013 Elsevier Inc. All rights reserved.

Using [11C]diprenorphine to image opioid receptor occupancy by methadone in opioid addiction: clinical and preclinical studies.

Science.gov (United States)

Melichar, Jan K; Hume, Susan P; Williams, Tim M; Daglish, Mark R C; Taylor, Lindsay G; Ahmad, Rabia; Malizia, Andrea L; Brooks, David J; Myles, Judith S; Lingford-Hughes, Anne; Nutt, David J

2005-01-01

Substitute methadone prescribing is one of the main modes of treatment for opioid dependence with established evidence for improved health and social outcomes. However, the pharmacology underpinning the effects of methadone is little studied despite controversies about dosing in relation to outcome. We therefore examined the relationship between methadone dose and occupation of opioid receptors in brain using the positron emission tomography (PET) radioligand [(11)C]diprenorphine in humans and rats. Eight opioid-dependent subjects stable on their substitute methadone (18-90 mg daily) had an [(11)C]diprenorphine PET scan at predicted peak plasma levels of methadone. These were compared with eight healthy controls. No difference in [(11)C]diprenorphine binding was found between the groups, with no relationship between methadone dose and occupancy. Adult male Sprague-Dawley rats that had been given an acute i.v. injection of methadone hydrochloride (0.35, 0.5, 0.7, or 1.0 mg kg(-1)) before [(11)C]diprenorphine showed a dose-dependent increase in biodistribution but no reduction in [(11)C]diprenorphine binding. We suggest that the lack of a dose-dependent relationship between methadone dose, either given chronically in human or acutely in rat, and occupancy of opioid receptor measured with [(11)C]diprenorphine PET is related to efficacy of this opioid agonist at very low levels of opioid receptor occupancy. This has implications for understanding the actions of methadone in comparison with other opioid drugs such as partial agonists and antagonists.

Drugs acting on amino acid neurotransmitters.

Science.gov (United States)

Meldrum, B S

1986-01-01

The most potent agents currently available for suppressing myoclonic activity in animals and humans act to enhance GABA-mediated inhibition and/or to diminish amino acid-induced excitation. Postsynaptic GABA-mediated inhibition plays an important role at the cortical level, diminishing the effect of augmented afferent activity and preventing pathologically enhanced output. Enhancement of GABAergic inhibition, principally at the cortical level but also at lower levels, by clonazepam and by valproate appears to be a predominant element in their antimyoclonic action. Studies in various animal models, including photically induced myoclonus in the baboon, P papio, indicate the value of other approaches to enhancing GABA-mediated inhibition. Among such approaches meriting evaluation in humans are inhibition of GABA-transaminase activity by gamma-vinyl GABA and action at some of the benzodiazepine receptors to enhance the action of GABA, as by the novel anticonvulsant beta-carbolines. Excitatory transmission mediated by dicarboxylic amino acids appears to play a role in myoclonus, especially at the spinal level, but also in the brainstem, cerebellum, basal ganglia, and cortex. Among various novel agents that act at the postsynaptic receptor site to antagonize such excitation, those specifically blocking excitation induced by aspartate and/or NMDA prevent myoclonic activity in a wide range of animal models. Further research is required before such agents can be evaluated in humans.

Nurses and opioids: results of a bi-national survey on mental models regarding opioid administration in hospitals.

Science.gov (United States)

Guest, Charlotte; Sobotka, Fabian; Karavasopoulou, Athina; Ward, Stephen; Bantel, Carsten

2017-01-01

Pain remains insufficiently treated in hospitals. Increasing evidence suggests human factors contribute to this, due to nurses failing to administer opioids. This behavior might be the consequence of nurses' mental models about opioids. As personal experience and conceptions shape these models, the aim of this prospective survey was to identify model-influencing factors. A questionnaire was developed comprising of 14 statements concerning ideations about opioids and seven questions concerning demographics, indicators of adult learning, and strength of religious beliefs. Latent variables that may underlie nurses' mental models were identified using undirected graphical dependence models. Representative items of latent variables were employed for ordinal regression analysis. Questionnaires were distributed to 1,379 nurses in two London, UK, hospitals (n=580) and one German (n=799) hospital between September 2014 and February 2015. A total of 511 (37.1%) questionnaires were returned. Mean (standard deviation) age of participants were 37 (11) years; 83.5% participants were female; 45.2% worked in critical care; and 51.5% had more than 10 years experience. Of the nurses, 84% were not scared of opioids, 87% did not regard opioids as drugs to help patients die, and 72% did not view them as drugs of abuse. More English (41%) than German (28%) nurses were afraid of criminal investigations and were constantly aware of side effects (UK, 94%; Germany, 38%) when using opioids. Four latent variables were identified which likely influence nurses' mental models: "conscious decision-making"; "medication-related fears"; "practice-based observations"; and "risk assessment". They were predicted by strength of religious beliefs and indicators of informal learning such as experience but not by indicators of formal learning such as conference attendance. Nurses in both countries employ analytical and affective mental models when administering the opioids and seem to learn from experience

State Emergency Department Opioid Guidelines: Current Status.

Science.gov (United States)

Broida, Robert I; Gronowski, Tanner; Kalnow, Andrew F; Little, Andrew G; Lloyd, Christopher M

2017-04-01

The purpose of this study was to evaluate and categorize current state-sponsored opioid guidelines for the practice of emergency medicine (EM). We conducted a comprehensive search of EM-specific opioid prescribing guidelines and/or policies in each state to determine current state involvement in EM opioid prescribing, as well as to evaluate some of the specifics of each guideline or policy. The search was conducted using an online query and a follow-up email request to each state chapter of ACEP. We found that 17 states had emergency department-specific guidelines. We further organized the guidelines into four categories: limiting prescriptions for opioids with 67 total recommendations; preventing/diverting abuse with 56 total recommendations; addiction-related guidelines with 29 total recommendations; and a community resources section with 24 total recommendations. Our results showed that current state guidelines focus on providers limiting opioid pain prescriptions and vetting patients for possible abuse/diversion. This study highlights the 17 states that have addressed opioid prescribing guidelines and categorizes their efforts to date. It is hoped that this study will provide the basis for similar efforts in other states.

Opioid mediated activity and expression of mu and delta opioid receptors in isolated human term non-labouring myometrium.

LENUS (Irish Health Repository)

Fanning, Rebecca A

2013-01-05

The existence of opioid receptors in mammalian myometrial tissue is now widely accepted. Previously enkephalin degrading enzymes have been shown to be elevated in pregnant rat uterus and a met-enkephalin analogue has been shown to alter spontaneous contractility of rat myometrium. Here we have undertaken studies to determine the effects of met-enkephalin on in vitro human myometrial contractility and investigate the expression of opioid receptors in pregnant myometrium. Myometrial biopsies were taken from women undergoing elective caesarean delivery at term. Organ bath experiments were used to investigate the effect of the met-enkephalin analogue [d-Ala 2, d-met 5] enkephalin (DAMEA) on spontaneous contractility. A confocal immunofluorescent technique and real time PCR were used to determine the expression of protein and mRNA, respectively for two opioid receptor subtypes, mu and delta. DAMEA had a concentration dependent inhibitory effect on contractile activity (1 × 10(-7)M-1 × 10(-4)M; 54% reduction in contractile activity, P<0.001 at 1 × 10(-4)M concentration). Mu and delta opioid receptor protein sub-types and their respective mRNA were identified in all tissues sampled. This is the first report of opioid receptor expression and of an opioid mediated uterorelaxant action in term human non-labouring myometrium in vitro.

Paraventricular Nucleus Modulates Excitatory Cardiovascular Reflexes during Electroacupuncture

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Tjen-A-Looi, Stephanie C.; Guo, Zhi-Ling; Fu, Liang-Wu; Longhurst, John C.

2016-01-01

The paraventricular nucleus (PVN) regulates sympathetic outflow and blood pressure. Somatic afferent stimulation activates neurons in the hypothalamic PVN. Parvocellular PVN neurons project to sympathoexcitatory cardiovascular regions of the rostral ventrolateral medulla (rVLM). Electroacupuncture (EA) stimulates the median nerve (P5-P6) to modulate sympathoexcitatory responses. We hypothesized that the PVN and its projections to the rVLM participate in the EA-modulation of sympathoexcitatory cardiovascular responses. Cats were anesthetized and ventilated. Heart rate and mean blood pressure were monitored. Application of bradykinin every 10-min on the gallbladder induced consistent pressor reflex responses. Thirty-min of bilateral EA stimulation at acupoints P5-P6 reduced the pressor responses for at least 60-min. Inhibition of the PVN with naloxone reversed the EA-inhibition. Responses of cardiovascular barosensitive rVLM neurons evoked by splanchnic nerve stimulation were reduced by EA and then restored with opioid receptor blockade in the PVN. EA at P5-P6 decreased splanchnic evoked activity of cardiovascular barosensitive PVN neurons that also project directly to the rVLM. PVN neurons labeled with retrograde tracer from rVLM were co-labeled with μ-opioid receptors and juxtaposed to endorphinergic fibers. Thus, the PVN and its projection to rVLM are important in processing acupuncture modulation of elevated blood pressure responses through a PVN opioid mechanism. PMID:27181844

Provider confidence in opioid prescribing and chronic pain management: results of the Opioid Therapy Provider Survey

Science.gov (United States)

Pearson, Amy CS; Moman, Rajat N; Moeschler, Susan M; Eldrige, Jason S; Hooten, W Michael

2017-01-01

Introduction Many providers report lack of confidence in managing patients with chronic pain. Thus, the primary aim of this study was to investigate the associations of provider confidence in managing chronic pain with their practice behaviors and demographics. Materials and methods The primary outcome measure was the results of the Opioid Therapy Provider Survey, which was administered to clinicians attending a pain-focused continuing medical education conference. Nonparametric correlations were assessed using Spearman’s rho. Results Of the respondents, 55.0% were women, 92.8% were white, and 56.5% were physicians. Primary care providers accounted for 56.5% of the total respondents. The majority of respondents (60.8%) did not feel confident managing patients with chronic pain. Provider confidence in managing chronic pain was positively correlated with 1) following an opioid therapy protocol (P=0.001), 2) the perceived ability to identify patients at risk for opioid misuse (P=0.006), and 3) using a consistent practice-based approach to improve their comfort level with prescribing opioids (Pcorrelated with the perception that treating pain patients was a “problem in my practice” (P=0.005). Conclusion In this study, the majority of providers did not feel confident managing chronic pain. However, provider confidence was associated with a protocolized and consistent practice-based approach toward managing opioids and the perceived ability to identify patients at risk for opioid misuse. Future studies should investigate whether provider confidence is associated with measurable competence in managing chronic pain and explore approaches to enhance appropriate levels of confidence in caring for patients with chronic pain. PMID:28652805

Excitatory and inhibitory synaptic mechanisms at the first stage of integration in the electroreception system of the shark

DEFF Research Database (Denmark)

Rotem, Naama; Sestieri, Emanuel; Hounsgaard, Jørn Dybkjær

2014-01-01

High impulse rate in afferent nerves is a common feature in many sensory systems that serve to accommodate a wide dynamic range. However, the first stage of integration should be endowed with specific properties that enable efficient handling of the incoming information. In elasmobranches...... of this afferent pathway. We found that stimulating the afferent nerve activates a mixture of excitatory and inhibitory synapses mediated by AMPA-like and GABAA receptors, respectively. The excitatory synapses that are extremely efficient in activating the postsynaptic neurons display unusual voltage dependence......, enabling them to operate as a current source. The inhibitory input is powerful enough to completely eliminate the excitatory action of the afferent nerve but is ineffective regarding other excitatory inputs. These observations can be explained by the location and efficiency of the synapses. We conclude...

Opioid-use disorder among patients on long-term opioid therapy: impact of final DSM-5 diagnostic criteria on prevalence and correlates.

Science.gov (United States)

Boscarino, Joseph A; Hoffman, Stuart N; Han, John J

2015-01-01

Previously, we estimated the prevalence and risk factors for prescription opioid-use disorder among outpatients on opioid therapy using the Diagnostic and Statistical Manual of Mental Disorders (DSM)-5 and DSM-4 criteria. However, at the time, the DSM-5 criteria were not finalized. In the current study, we analyzed these data using the final DSM-5 criteria and compared these results. Using electronic records from a large US health care system, we identified outpatients receiving five or more prescription orders for opioid therapy in the past 12 months for noncancer pain (mean prescription orders =10.72; standard deviation =4.96). In 2008, we completed diagnostic interviews with 705 of these patients using the DSM-4 criteria. In the current study, we reassessed these results using the final DSM-5 criteria. The lifetime prevalence of DSM-5 opioid-use disorders using the final DSM-5 criteria was 58.7% for no or few symptoms (DSM-4 criteria indicated that the majority of patients with lifetime DSM-4 opioid dependence were now classified as having mild opioid-use disorder, based on the DSM-5 criteria (53.6%; 95% CI =44.1-62.8). In ordinal logistic regression predicting no/few, mild, moderate, and severe opioid-use disorder, the best predictors were age DSM-5 criteria, including the elimination of tolerance and withdrawal, inclusion of craving and abuse symptoms, and introduction of a new graded severity classification, the prevalence of opioid-use disorders has changed, while many of the DSM-4 risk factors for opioid dependence were similar. To our knowledge, this is one of the first studies to compare the final results for DSM-5 versus DSM-4 prescription opioid-use disorders among a high-risk patient population.

Comorbid Post-Traumatic Stress Disorder and Opioid Dependence.

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Patel, Rikinkumar S; Elmaadawi, Ahmed; Nasr, Suhayl; Haskin, John

2017-09-03

Post-traumatic stress disorder (PTSD) is predominant amongst individuals addicted to opioids and obscures the course of illness and the treatment outcome. We report the case of a patient with major depressive disorder and opioid dependence, who experienced post-traumatic stress disorder symptoms during a recent visit to the inpatient unit. The similarity of symptoms between post-traumatic stress disorder and opioid dependence is so high that, sometimes, it is a challenge to differentiate between these conditions. Since opioid withdrawal symptoms mimic hyper vigilance, this results in an exaggeration of the response of patients with post-traumatic stress disorder. This comorbidity is associated with worse health outcomes, as its pathophysiology involves a common neurobiological circuit. Opioid substitution therapy and psychotherapeutic medications in combination with evidence-based cognitive behavioral therapy devised for individuals with comorbid post-traumatic stress disorder and opioid dependence may improve treatment outcomes in this population. Therefore, we conclude that the screening for post-traumatic stress disorder in the opioid-abusing population is crucial. To understand the underlying mechanisms for this comorbidity and to improve the treatment response, further research should be encouraged.

Risk Factors for Opioid-Use Disorder and Overdose.

Science.gov (United States)

Webster, Lynn R

2017-11-01

Opioid analgesics are recognized as a legitimate medical therapy for selected patients with severe chronic pain that does not respond to other therapies. However, opioids are associated with risks for patients and society that include misuse, abuse, diversion, addiction, and overdose deaths. Therapeutic success depends on proper candidate selection, assessment before administering opioid therapy, and close monitoring throughout the course of treatment. Risk assessment and prevention include knowledge of patient factors that may contribute to misuse, abuse, addiction, suicide, and respiratory depression. Risk factors for opioid misuse or addiction include past or current substance abuse, untreated psychiatric disorders, younger age, and social or family environments that encourage misuse. Opioid mortality prevalence is higher in people who are middle aged and have substance abuse and psychiatric comorbidities. Suicides are probably undercounted or frequently misclassified in reports of opioid-related poisoning deaths. Greater understanding and better assessment are needed of the risk associated with suicide risk in patients with pain. Clinical tools and an evolving evidence base are available to assist clinicians with identifying patients whose risk factors put them at risk for adverse outcomes with opioids.

Bistability Analysis of Excitatory-Inhibitory Neural Networks in Limited-Sustained-Activity Regime

International Nuclear Information System (INIS)

Ni Yun; Wu Liang; Wu Dan; Zhu Shiqun

2011-01-01

Bistable behavior of neuronal complex networks is investigated in the limited-sustained-activity regime when the network is composed of excitatory and inhibitory neurons. The standard stability analysis is performed on the two metastable states separately. Both theoretical analysis and numerical simulations show consistently that the difference between time scales of excitatory and inhibitory populations can influence the dynamical behaviors of the neuronal networks dramatically, leading to the transition from bistable behaviors with memory effects to the collapse of bistable behaviors. These results may suggest one possible neuronal information processing by only tuning time scales. (interdisciplinary physics and related areas of science and technology)

Expression of gastrin-releasing peptide by excitatory interneurons in the mouse superficial dorsal horn.

Science.gov (United States)

Gutierrez-Mecinas, Maria; Watanabe, Masahiko; Todd, Andrew J

2014-12-11

Gastrin-releasing peptide (GRP) and its receptor have been shown to play an important role in the sensation of itch. However, although GRP immunoreactivity has been detected in the spinal dorsal horn, there is debate about whether this originates from primary afferents or local excitatory interneurons. We therefore examined the relation of GRP immunoreactivity to that seen with antibodies that label primary afferent or excitatory interneuron terminals. We tested the specificity of the GRP antibody by preincubating with peptides with which it could potentially cross-react. We also examined tissue from a mouse line in which enhanced green fluorescent protein (EGFP) is expressed under control of the GRP promoter. GRP immunoreactivity was seen in both primary afferent and non-primary glutamatergic axon terminals in the superficial dorsal horn. However, immunostaining was blocked by pre-incubation of the antibody with substance P, which is present at high levels in many nociceptive primary afferents. EGFP+ cells in the GRP-EGFP mouse did not express Pax2, and their axons contained the vesicular glutamate transporter 2 (VGLUT2), indicating that they are excitatory interneurons. In most cases, their axons were also GRP-immunoreactive. Multiple-labelling immunocytochemical studies indicated that these cells did not express either of the preprotachykinin peptides, and that they generally lacked protein kinase Cγ, which is expressed by a subset of the excitatory interneurons in this region. These results show that GRP is expressed by a distinct population of excitatory interneurons in laminae I-II that are likely to be involved in the itch pathway. They also suggest that the GRP immunoreactivity seen in primary afferents in previous studies may have resulted from cross-reaction of the GRP antibody with substance P or the closely related peptide neurokinin A.

Hiperalgesia asociada al tratamiento con opioides

OpenAIRE

A. Gil Martín; M. Moreno García; J. Sánchez-Rubio Ferrández; T. Molina García

2014-01-01

La hiperalgesia inducida por opioides es una reacción paradójica caracterizada por una percepción intensificada de dolor relacionada con el uso de estos medicamentos en ausencia de progresión de la enfermedad o de síndrome de retirada. A diferencia de los casos de tolerancia, definida como pérdida de potencia analgésica durante el uso prolongado de opioides, no se produce mejoría con el escalado de dosis. La hiperalgesia inducida por opioides se ha manifestado en pacientes con dosis de manten...

Bilateral Breast Reduction Without Opioid Analgesics: A Comparative Study.

Science.gov (United States)

Parsa, Fereydoun Don; Cheng, Justin; Stephan, Brad; Castel, Nikki; Kim, Leslie; Murariu, Daniel; Parsa, Alan A

2017-09-01

Breast reduction has traditionally been performed under general anesthesia with adjunct opioid use. However, opioids are associated with a wide variety of adverse effects, including nausea, vomiting, constipation, postoperative sedation, dizziness, and addiction. This study compares bilateral breast reduction using a multimodal opioid-free pain management regimen vs traditional general anesthesia with adjunct opioids. A total of 83 female patients were enrolled in this study. Group 1 includes a retrospective series of 39 patients that underwent breast reduction via general anesthesia with adjunct opioid use. This series was compared to 2 prospective groups of patients who did not receive opioids either preoperatively or intraoperatively. In group 2, twenty-six patients underwent surgery under intravenous sedation and local anesthesia. In group 3, eighteen patients underwent surgery with general anesthesia. All patients in groups 2 and 3 received preoperative gabapentin and celecoxib along with infiltration of local anesthetics during the operation and prior to discharge to the Post-Anesthesia Care Unit (PACU). Primary outcome measures included the duration of surgery, time from end of operation to discharge home, postoperative opioid and antiemetic use, and unplanned postoperative hospitalizations. When compared to group 1, groups 2 and 3 experienced a shorter time from end of operation to discharge home (P opioid use (P opioid-free bilateral breast reduction either under local or general anesthesia as an outpatient. This method resulted in significantly less morbidity, use of opioids postoperatively, as well as unplanned hospital admissions compared to "traditional" breast reduction under general anesthesia with the use of opioids. 3. © 2017 The American Society for Aesthetic Plastic Surgery, Inc. Reprints and permission: journals.permissions@oup.com

Fentanyl and a Novel Synthetic Opioid U-47700 Masquerading as Street "Norco" in Central California: A Case Report.

Science.gov (United States)

Armenian, Patil; Olson, Alexander; Anaya, Andres; Kurtz, Alicia; Ruegner, Rawnica; Gerona, Roy R

2017-01-01

In 2013 and 2014, more than 700 deaths were attributed to fentanyl and fentanyl analogues in the United States. Of recent concern is the cluster of unintentional fentanyl overdoses because of tablets thought to be "Norco" purchased on the street in Northern California. U-47700 (trans-3,4-dichloro-N-[2-(dimethyl-amino)cyclohexyl]-N-methylbenz-amide) is a nonfentanyl-based synthetic opioid with 7.5 times the binding affinity of morphine to μ-opioid. We report a case of fentanyl and U-47700 intoxication from what was thought to be illicitly purchased Norco. A 41-year-old woman presented to the emergency department (ED) for altered mental status shortly after ingesting 3 beige Norco pills bearing a Watson imprint. She had pinpoint pupils and respiratory depression, which reversed after 0.4 mg naloxone administration intravenously. She had complete recovery and was discharged from the ED after a 4-hour observation period. Serum testing with liquid chromatography-quadrupole time-of-flight mass spectrometry (LC 1260 QTOF/MS 6550; Agilent, Santa Clara, CA) confirmed the presence of the medications the patient reported receiving, and additionally fentanyl (15.2 ng/mL) and U-47700 (7.6 ng/mL). In this case report, street Norco purchased in Central California resulted in altered mental status requiring naloxone reversal because of fentanyl and the novel synthetic opioid U-47700. Because these compounds are not detected by routine urine drug testing and physical examination findings are similar to those of a traditional opioid toxidrome, emergency providers should use the patient's history and other circumstantial details to aid in diagnosis. In cases with suspicion of opioid or opioid analogue cause, we recommend that emergency providers contact their local poison control center, medical toxicologist, or public health department to aid in the investigation. Copyright © 2016 American College of Emergency Physicians. Published by Elsevier Inc. All rights reserved.

Opioid Overdose

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... Updated: 03/10/2016 Medications to Treat OPIOID ADDICTION Methadone Naltrexone Buprenorphine Related SAMHSA Resources Behavioral Health ... Systems Integration Health Disparities Health Financing Health Information Technology HIV, AIDS, and Viral Hepatitis Homelessness and Housing ...

Behavioral intervention to reduce opioid overdose among high-risk persons with opioid use disorder: A pilot randomized controlled trial.

Directory of Open Access Journals (Sweden)

Phillip Oliver Coffin

Full Text Available The United States is amidst an opioid epidemic, including synthetic opioids that may result in rapid death, leaving minimal opportunity for bystander rescue. We pilot tested a behavioral intervention to reduce the occurrence of opioid overdose among opioid dependent persons at high-risk for subsequent overdose.We conducted a single-blinded randomized-controlled trial of a repeated dose motivational interviewing intervention (REBOOT to reduce overdose versus treatment as usual, defined as information and referrals, over 16 months at the San Francisco Department of Public Health from 2014-2016. Participants were 18-65 years of age, had opioid use disorder by Structured Clinical Interview, active opioid use, opioid overdose within 5 years, and prior receipt of naloxone kits. The intervention was administered at months 0, 4, 8, and 12, preceded by the assessment which was also administered at month 16. Dual primary outcomes were any overdose event and number of events, collected by computer-assisted personal interview, as well as any fatal overdose events per vital records.A total of 78 persons were screened and 63 enrolled. Mean age was 43 years, 67% were born male, 65% White, 17% African-American, and 14% Latino. Ninety-two percent of visits and 93% of counseling sessions were completed. At baseline, 33.3% of participants had experienced an overdose in the past four months, with a similar mean number of overdoses in both arms (p = 0.95; 29% overdosed during follow-up. By intention-to-treat, participants assigned to REBOOT were less likely to experience any overdose (incidence rate ratio [IRR] 0.62 [95%CI 0.41-0.92, p = 0.019 and experienced fewer overdose events (IRR 0.46, 95%CI 0.24-0.90, p = 0.023, findings that were robust to sensitivity analyses. There were no differences between arms in days of opioid use, substance use treatment, or naloxone carriage.REBOOT reduced the occurrence of any opioid overdose and the number of overdoses

Induction of synaptic long-term potentiation after opioid withdrawal.

Science.gov (United States)

Drdla, Ruth; Gassner, Matthias; Gingl, Ewald; Sandkühler, Jürgen

2009-07-10

mu-Opioid receptor (MOR) agonists represent the gold standard for the treatment of severe pain but may paradoxically also enhance pain sensitivity, that is, lead to opioid-induced hyperalgesia (OIH). We show that abrupt withdrawal from MOR agonists induces long-term potentiation (LTP) at the first synapse in pain pathways. Induction of opioid withdrawal LTP requires postsynaptic activation of heterotrimeric guanine nucleotide-binding proteins and N-methyl-d-aspartate receptors and a rise of postsynaptic calcium concentrations. In contrast, the acute depression by opioids is induced presynaptically at these synapses. Withdrawal LTP can be prevented by tapered withdrawal and shares pharmacology and signal transduction pathways with OIH. These findings provide a previously unrecognized target to selectively combat pro-nociceptive effects of opioids without compromising opioid analgesia.

Access to opioids: a global pain management crisis.

Science.gov (United States)

Buitrago, Rosa

2013-03-01

The lack of availability of opioids in many countries has created a pain management crisis. Because the Single Convention on Narcotic Drugs requires governments to report annual opioid statistics, there is a need for methods to calculate individual nations' opioid needs. Ways to address this need are discussed.

The opioid ketobemidone has a NMDA blocking effect

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Andersen, S; Dickenson, A H; Kohn, M

1996-01-01

There are clinical observations that neurogenic pain can respond well to the opioid ketobemidone, in contrast to pethidine and morphine. This has led us to the hypothesis that the analgesic effect of ketobemidone in neurogenic pain may be due to both opioid as well as additional non-opioid effect...

Computational opioid prescribing: a novel application of clinical pharmacokinetics.

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Linares, Oscar A; Linares, Annemarie L

2011-01-01

We implemented a pharmacokinetics-based mathematical modeling technique using algebra to assist prescribers with point-of-care opioid dosing. We call this technique computational opioid prescribing (COP). Because population pharmacokinetic parameter values are needed to estimate drug dosing regimen designs for individual patients using COP, and those values are not readily available to prescribers because they exist scattered in the vast pharmacology literature, we estimated the population pharmacokinetic parameter values for 12 commonly prescribed opioids from various sources using the bootstrap resampling technique. Our results show that opioid dosing regimen design, evaluation, and modification is feasible using COP. We conclude that COP is a new technique for the quantitative assessment of opioid dosing regimen design evaluation and adjustment, which may help prescribers to manage acute and chronic pain at the point-of-care. Potential benefits include opioid dose optimization and minimization of adverse opioid drug events, leading to potential improvement in patient treatment outcomes and safety.

Treating opioid dependence. Growing implications for primary care.

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Krantz, Mori J; Mehler, Philip S

2004-02-09

Almost 3 million Americans have abused heroin. The most effective treatment for this concerning epidemic is opioid replacement therapy. Although, from a historical perspective, acceptance of this therapy has been slow, growing evidence supports its efficacy. There are 3 approved medications for opioid maintenance therapy: methadone hydrochloride, levomethadyl acetate, and buprenorphine hydrochloride. Each has unique characteristics that determine its suitability for an individual patient. Cardiac arrhythmias have been reported with methadone and levomethadyl, but not with buprenorphine. Due to concerns about cardiac risk, levomethadyl use has declined and the product may ultimately be discontinued. These recent safety concerns, specifics about opioid detoxification and maintenance, and new federal initiatives were studied. Opioid detoxification has a role in both preventing acute withdrawal and maintaining long-term abstinence. Although only a minority of eligible patients are engaged in treatment, opioid maintenance therapy appears to offer the greatest public health benefits. There is growing interest in expanding treatment into primary care, allowing opioid addiction to be managed like other chronic illnesses. This model has gained wide acceptance in Europe and is now being implemented in the United States. The recent Drug Addiction Treatment Act enables qualified physicians to treat opioid-dependent patients with buprenorphine in an office-based setting. Mainstreaming opioid addiction treatment has many advantages; its success will depend on resolution of ethical and delivery system issues as well as improved and expanded training of physicians in addiction medicine.

Healthy Adult Male Facial Skin Surface Lipid Pheromone p.o. to Treat Opioid Addiction

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2018-03-20

Opioid Addiction; Opioid Abuse, Continuous Use; Opioid Use; Opioid-Related Disorders; Paternal Pheromone Deficiency; Opioid Dependence; Opioid Abuse; Opioid-use Disorder; Opioid Intoxication; Opioid Abuse, Episodic

Pain in the management of opioid use disorder

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Sirohi S

2016-11-01

Full Text Available Sunil Sirohi,1 Amit K Tiwari21Laboratory of Endocrine and Neuropsychiatric Disorders, Division of Basic Pharmaceutical Sciences, College of Pharmacy, Xavier University of Louisiana, New Orleans, LA, 2Department of Pharmacology and Experimental Therapeutics, College of Pharmacy and Pharmaceutical Sciences, University of Toledo, Toledo, OH, USAOpioids remain the drug of choice for the clinical management of moderate to severe pain. However, in addition to their most effective analgesic actions, opioids also produce a sense of well-being and euphoria, which may trigger significant concerns associated with their use.1 In fact, there has been an alarming increase in prescription opioid use, abuse and illicit use; and according to the National Center for Health Statistics, the total number of deaths related to opioid overdose has more than tripled from 2011 to 2014.2–5 Although representing 5.0 % of the global population, studies report that Americans consume 80% of the global opioid supply,3 and the United States is experiencing an opioid abuse epidemic.6 Considering this unprecedented rise in opioid consumption, the United States Centers for Disease Control and Prevention has listed prescription opioid overdose among one of the 10 most important public health problems in all the 50 states.7

Opioid Addiction

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... breathing rate nausea, vomiting constipation physical agitation poor decision making abandoning responsibilities slurred speech sleeping more or less than normal mood swings euphoria (feeling high) irritability depression lowered motivation anxiety attacks. Symptoms of opioid overdose An overdose ...

Medication-Assisted Treatment For Opioid Addiction in Opioid Treatment Programs. Treatment Improvement Protocol (TIP) Series 43

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Tinkler, Emily; Vallejos Bartlett, Catalina; Brooks, Margaret; Gilbert, Johnatnan Max; Henderson, Randi; Shuman, Deborah, J.

2005-01-01

TIP 43 provides best-practice guidelines for medication-assisted treatment of opioid addiction in opioid treatment programs (OTPs). The primary intended audience for this volume is substance abuse treatment providers and administrators who work in OTPs. Recommendations in the TIP are based on both an analysis of current research and determinations…

Is there a role for opioids in the treatment of fibromyalgia?

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Littlejohn, Geoffrey O; Guymer, Emma K; Ngian, Gene-Siew

2016-05-01

The use of opioids for chronic pain has increased significantly due to a combination of the high patient burden of pain and the more widespread availability of a range of long-acting opioid preparations. This increased opioid use has translated into the care of many patients with fibromyalgia. The pain mechanism in fibromyalgia is complex but does not seem to involve disturbance of opioid analgesic functions. Hence, there is general concern about the harms in the absence of benefits of opioids in this setting. There is no evidence that pure opioids are effective in fibromyalgia but there is some evidence that opioids with additional actions on the norepinephrine-related pain modulatory pathways, such as tramadol, can be clinically useful in some patients. Novel actions of low-dose opioid antagonists may lead to better understanding of the role of opioid function in fibromyalgia.

Endogenous opioids regulate moment-to-moment neuronal communication and excitability

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Winters, Bryony L.; Gregoriou, Gabrielle C.; Kissiwaa, Sarah A.; Wells, Oliver A.; Medagoda, Danashi I.; Hermes, Sam M.; Burford, Neil T.; Alt, Andrew; Aicher, Sue A.; Bagley, Elena E.

2017-01-01

Fear and emotional learning are modulated by endogenous opioids but the cellular basis for this is unknown. The intercalated cells (ITCs) gate amygdala output and thus regulate the fear response. Here we find endogenous opioids are released by synaptic stimulation to act via two distinct mechanisms within the main ITC cluster. Endogenously released opioids inhibit glutamate release through the δ-opioid receptor (DOR), an effect potentiated by a DOR-positive allosteric modulator. Postsynaptically, the opioids activate a potassium conductance through the μ-opioid receptor (MOR), suggesting for the first time that endogenously released opioids directly regulate neuronal excitability. Ultrastructural localization of endogenous ligands support these functional findings. This study demonstrates a new role for endogenously released opioids as neuromodulators engaged by synaptic activity to regulate moment-to-moment neuronal communication and excitability. These distinct actions through MOR and DOR may underlie the opposing effect of these receptor systems on anxiety and fear. PMID:28327612

The challenge of perioperative pain management in opioid-tolerant patients

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Coluzzi, Flaminia; Bifulco, Francesca; Cuomo, Arturo; Dauri, Mario; Leonardi, Claudio; Melotti, Rita Maria; Natoli, Silvia; Romualdi, Patrizia; Savoia, Gennaro; Corcione, Antonio

2017-01-01

The increasing number of opioid users among chronic pain patients, and opioid abusers among the general population, makes perioperative pain management challenging for health care professionals. Anesthesiologists, surgeons, and nurses should be familiar with some pharmacological phenomena which are typical of opioid users and abusers, such as tolerance, physical dependence, hyperalgesia, and addiction. Inadequate pain management is very common in these patients, due to common prejudices and fears. The target of preoperative evaluation is to identify comorbidities and risk factors and recognize signs and symptoms of opioid abuse and opioid withdrawal. Clinicians are encouraged to plan perioperative pain medications and to refer these patients to psychiatrists and addiction specialists for their evaluation. The aim of this review was to give practical suggestions for perioperative management of surgical opioid-tolerant patients, together with schemes of opioid conversion for chronic pain patients assuming oral or transdermal opioids, and patients under maintenance programs with methadone, buprenorphine, or naltrexone. PMID:28919771

Loss of MeCP2 From Forebrain Excitatory Neurons Leads to Cortical Hyperexcitation and Seizures

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Zhang, Wen; Peterson, Matthew; Beyer, Barbara; Frankel, Wayne N.

2014-01-01

Mutations of MECP2 cause Rett syndrome (RTT), a neurodevelopmental disorder leading to loss of motor and cognitive functions, impaired social interactions, and seizure at young ages. Defects of neuronal circuit development and function are thought to be responsible for the symptoms of RTT. The majority of RTT patients show recurrent seizures, indicating that neuronal hyperexcitation is a common feature of RTT. However, mechanisms underlying hyperexcitation in RTT are poorly understood. Here we show that deletion of Mecp2 from cortical excitatory neurons but not forebrain inhibitory neurons in the mouse leads to spontaneous seizures. Selective deletion of Mecp2 from excitatory but not inhibitory neurons in the forebrain reduces GABAergic transmission in layer 5 pyramidal neurons in the prefrontal and somatosensory cortices. Loss of MeCP2 from cortical excitatory neurons reduces the number of GABAergic synapses in the cortex, and enhances the excitability of layer 5 pyramidal neurons. Using single-cell deletion of Mecp2 in layer 2/3 pyramidal neurons, we show that GABAergic transmission is reduced in neurons without MeCP2, but is normal in neighboring neurons with MeCP2. Together, these results suggest that MeCP2 in cortical excitatory neurons plays a critical role in the regulation of GABAergic transmission and cortical excitability. PMID:24523563

Reviewing opioid use, monitoring, and legislature: Nursing perspectives

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Deniece A. Jukiewicz

2017-10-01

Full Text Available The phenomena of prescription opioid misuse and abuse have a complicated history of contributing factors including policies, practices, and prescribing leading to contemporary phenomena. Some factors implicated in the opioid drug abuse problem include inefficient prescribing and improper use, lack of knowledge related to interpretation and assessment of pain levels, and decreased oversight and regulation from government and policy agents. Nurses, often frontline providers, need to be knowledgeable and embrace the guidelines, and necessary implications associated with both prescribing and administration of opioids. Additionally, all providers including physicians, physician assistants, nurse practitioners, and bedside nurses must have a firm understanding of the improper use and abuse of opioids. The examination and review of opioid policies at the state and federal level has revealed inconsistency with regulations, policies, and guidelines that have lead to the current situation. The use of an interdisciplinary team with nurses and various other practitioners is a good strategy to help reduce this problem. Keywords: Abuse, Administration, Legislature, Nursing, Opioid, Overdose, Policy, Prescribing

Preventing Opioid Use Disorders among Fishing Industry Workers

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Angela Wangari Walter

2018-03-01

Full Text Available Fishing industry workers are at high risk for work-related musculoskeletal disorders (MSDs and injuries. Prescription opioids used to treat pain injuries may put these workers at increased risk for developing substance disorders. Using a Community-Based Participatory Research approach, formative research was conducted to inform the eventual development of relevant interventions to prevent and reduce opioid use disorders among fishing industry workers. Qualitative interviews (n = 21 were conducted to assess: knowledge and attitudes about opioid use disorders; features of fishing work that might affect use and/or access to treatment; and community and organizational capacity for prevention and treatment. Participants reported numerous pathways connecting commercial fishing with opioid use. The combination of high stress and physically tasking job duties requires comprehensive workplace interventions to prevent chronic pain and MSDs, in addition to tailored and culturally responsive treatment options to address opioid use disorders in this population. Public health programs must integrate workplace health and safety protection along with evidence-based primary, secondary, and tertiary interventions in order to address opioid use disorders, particularly among workers in strenuous jobs.

Knowledge of Opioid Overdose and Attitudes to Supply of Take-Home Naloxone Among People with Chronic Noncancer Pain Prescribed Opioids.

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Nielsen, Suzanne; Peacock, Amy; Lintzeris, Nicholas; Bruno, Raimondo; Larance, Briony; Degenhardt, Louisa

2018-03-01

Take-home naloxone (THN) is recommended in response to pharmaceutical opioid-related mortality. Some health professionals are reluctant to discuss THN for fear of causing offense. The aims of this study were to assess knowledge of opioid overdose and attitudes toward THN for opioid overdose reversal in people with chronic noncancer pain (CNCP). Prospective cohort study. Australia, September to October 2015. A subset of participants (N = 208) from a cohort of people prescribed restricted opioids for CNCP. Questions added in the two-year telephone interviews examined knowledge of overdose symptoms and attitudes toward community supply of naloxone. Associations with overdose risk factors and naloxone supply eligibility criteria with attitudes toward naloxone were explored. Fourteen percent reported ever experiencing opioid overdose symptoms. Participants correctly identified fewer than half of the overdose signs and symptoms. After receiving information on naloxone, most participants (60%), thought it was a "good" or "very good" idea. Few participants reported that they would be "a little" (N = 21, 10%) or "very" offended (N = 7, 3%) if their opioid prescriber offered them naloxone. Positive attitudes toward THN were associated with male gender (odds ratio [OR] = 1.96, 95% confidence interval [CI] = 1.09-3.50), past year cannabis use (OR = 2.52, 95% CI = 1.03-6.16), and past year nicotine use (OR = 2.11, 95% CI = 1.14-3.91). Most participants had positive attitudes toward THN but low knowledge about opioid overdose symptoms. Strategies for educating patients and their caregivers on opioid toxicity are needed. THN may be best targeted toward those with risk factors in terms of overdose prevention and acceptability.

Managing Opioid Addiction Risk in Plastic Surgery during the Perioperative Period.

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Demsey, Daniel; Carr, Nicholas J; Clarke, Hance; Vipler, Sharon

2017-10-01

Opioid addiction is a public health crisis that affects all areas of medicine. Large numbers of the population across all racial and economic demographics misuse prescription opioids and use illicit opioids. The current understanding is that opioid misuse is a disease that requires treatment, and is not an issue of choice or character. Use of opioid medication is a necessary part of postoperative analgesia, but many physicians are unsure of how to do this safely given the risk of patients developing an opioid misuse disorder. This review gives an update of the current state of the opioid crisis, explains how current surgeons' prescribing practices are contributing to it, and gives recommendations on how to use opioid medication safely in the perioperative period.

Opioid withdrawal syndrome: emerging concepts and novel therapeutic targets.

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Rehni, Ashish K; Jaggi, Amteshwar S; Singh, Nirmal

2013-02-01

Opioid withdrawal syndrome is a debilitating manifestation of opioid dependence and responds poorly to the available clinical therapies. Studies from various in vivo and in vitro animal models of opioid withdrawal syndrome have led to understanding of its pathobiology which includes complex interrelated pathways leading to adenylyl cyclase superactivation based central excitation. Advancements in the elucidation of opioid withdrawal syndrome mechanisms have revealed a number of key targets that have been hypothesized to modulate clinical status. The present review discusses the neurobiology of opioid withdrawal syndrome and its therapeutic target recptors like calcitonin gene related peptide receptors (CGRP), N-methyl-D-aspartate (NMDA) receptors, gamma aminobutyric acid receptors (GABA), G-proteingated inwardly rectifying potassium (GIRK) channels and calcium channels. The present review further details the potential role of second messengers like calcium (Ca2+) / calmodulin-dependent protein kinase (CaMKII), nitric oxide synthase, cytokines, arachidonic acid metabolites, corticotropin releasing factor, fos and src kinases in causing opioid withdrawal syndrome. The exploitation of these targets may provide effective therapeutic agents for the management of opioid dependence-induced abstinence syndrome.

A Trigger for Opioid Misuse: Chronic Pain and Stress Dysregulate the Mesolimbic Pathway and Kappa Opioid System.

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Massaly, Nicolas; Morón, Jose A; Al-Hasani, Ream

2016-01-01

Pain and stress are protective mechanisms essential in avoiding harmful or threatening stimuli and ensuring survival. Despite these beneficial roles, chronic exposure to either pain or stress can lead to maladaptive hormonal and neuronal modulations that can result in chronic pain and a wide spectrum of stress-related disorders including anxiety and depression. By inducing allostatic changes in the mesolimbic dopaminergic pathway, both chronic pain and stress disorders affect the rewarding values of both natural reinforcers, such as food or social interaction, and drugs of abuse. Despite opioids representing the best therapeutic strategy in pain conditions, they are often misused as a result of these allostatic changes induced by chronic pain and stress. The kappa opioid receptor (KOR) system is critically involved in these neuronal adaptations in part through its control of dopamine release in the nucleus accumbens. Therefore, it is likely that changes in the kappa opioid system following chronic exposure to pain and stress play a key role in increasing the misuse liability observed in pain patients treated with opioids. In this review, we will discuss how chronic pain and stress-induced pathologies can affect mesolimbic dopaminergic transmission, leading to increased abuse liability. We will also assess how the kappa opioid system may underlie these pathological changes.

A trigger for opioid misuse: Chronic pain and stress dysregulate the mesolimbic pathway and kappa opioid system

Directory of Open Access Journals (Sweden)

Nicolas Massaly

2016-11-01

Full Text Available Pain and stress are protective mechanisms essential in avoiding harmful or threatening stimuli and ensuring survival. Despite these beneficial roles, chronic exposure to either pain or stress can lead to maladaptive hormonal and neuronal modulations that can result in chronic pain and a wide spectrum of stress-related disorders including anxiety and depression. By inducing allostatic changes in the mesolimbic dopaminergic pathway, both chronic pain and stress disorders affect the rewarding values of both natural reinforcers, such as food or social interaction, and drugs of abuse. Despite opioids representing the best therapeutic strategy in acute pain conditions, they are often misused as a result of these allostatic changes induced by chronic pain and stress. The kappa opioid receptor system is critically involved in these neuronal adaptations in part through its control of dopamine release in the nucleus accumbens. Therefore, it is likely that changes in the kappa opioid system following chronic exposure to pain and stress play a key role in increasing the misuse liability observed in pain patients treated with opioids. In this review, we will discuss how chronic pain and stress-induced pathologies can affect mesolimbic dopaminergic transmission, leading to increased abuse liability. We will also assess how the kappa opioid system may underlie these pathological changes.

Nurses and opioids: results of a bi-national survey on mental models regarding opioid administration in hospitals

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Guest C

2017-03-01

Full Text Available Charlotte Guest,1 Fabian Sobotka,2 Athina Karavasopoulou,3 Stephen Ward,3 Carsten Bantel4,5 1Pain Medicine, Chelsea and Westminster Hospital NHS Foundation Trust, London, UK; 2Division of Epidemiology and Biometry, Department of Health Services Research, Faculty 6, Medicine and Health Sciences, Carl von Ossietzky Universität Oldenburg, Oldenburg, Germany; 3Pain Service, Barts Health, St Bartholomew’s Hospital, London, UK; 4Department of Anaesthesiology, Intensive Care, Emergency Medicine and Pain Therapy, Oldenburg University, Klinikum Oldenburg Campus, Oldenburg, Germany; 5Department of Surgery and Cancer, Anaesthetics Section, Imperial College London, Chelsea and Westminster Hospital Campus, London, UK Objective: Pain remains insufficiently treated in hospitals. Increasing evidence suggests human factors contribute to this, due to nurses failing to administer opioids. This behavior might be the consequence of nurses’ mental models about opioids. As personal experience and conceptions shape these models, the aim of this prospective survey was to identify model-influencing factors. Material and methods: A questionnaire was developed comprising of 14 statements concerning ideations about opioids and seven questions concerning demographics, indicators of adult learning, and strength of religious beliefs. Latent variables that may underlie nurses’ mental models were identified using undirected graphical dependence models. Representative items of latent variables were employed for ordinal regression analysis. Questionnaires were distributed to 1,379 nurses in two London, UK, hospitals (n=580 and one German (n=799 hospital between September 2014 and February 2015. Results: A total of 511 (37.1% questionnaires were returned. Mean (standard deviation age of participants were 37 (11 years; 83.5% participants were female; 45.2% worked in critical care; and 51.5% had more than 10 years experience. Of the nurses, 84% were not scared of opioids, 87

An excitatory paraventricular nucleus to AgRP neuron circuit that drives hunger.

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Krashes, Michael J; Shah, Bhavik P; Madara, Joseph C; Olson, David P; Strochlic, David E; Garfield, Alastair S; Vong, Linh; Pei, Hongjuan; Watabe-Uchida, Mitsuko; Uchida, Naoshige; Liberles, Stephen D; Lowell, Bradford B

2014-03-13

Hunger is a hard-wired motivational state essential for survival. Agouti-related peptide (AgRP)-expressing neurons in the arcuate nucleus (ARC) at the base of the hypothalamus are crucial to the control of hunger. They are activated by caloric deficiency and, when naturally or artificially stimulated, they potently induce intense hunger and subsequent food intake. Consistent with their obligatory role in regulating appetite, genetic ablation or chemogenetic inhibition of AgRP neurons decreases feeding. Excitatory input to AgRP neurons is important in caloric-deficiency-induced activation, and is notable for its remarkable degree of caloric-state-dependent synaptic plasticity. Despite the important role of excitatory input, its source(s) has been unknown. Here, through the use of Cre-recombinase-enabled, cell-specific neuron mapping techniques in mice, we have discovered strong excitatory drive that, unexpectedly, emanates from the hypothalamic paraventricular nucleus, specifically from subsets of neurons expressing thyrotropin-releasing hormone (TRH) and pituitary adenylate cyclase-activating polypeptide (PACAP, also known as ADCYAP1). Chemogenetic stimulation of these afferent neurons in sated mice markedly activates AgRP neurons and induces intense feeding. Conversely, acute inhibition in mice with caloric-deficiency-induced hunger decreases feeding. Discovery of these afferent neurons capable of triggering hunger advances understanding of how this intense motivational state is regulated.

The evolution of chronic opioid therapy and recognizing addiction.

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Daum, Akiva M; Berkowitz, Oren; Renner, John A

2015-05-01

Chronic pain is one of the most common complaints in the United States. Opioids have become a frequently prescribed treatment for patients with chronic nonmalignant pain. Concurrently, opioid use disorders have risen to epidemic levels. Studies investigating iatrogenic opioid addiction have been of limited quality. Aberrant drug-related behaviors may be warning signs of impending addiction. Proper screening and close monitoring are essential for managing patients on opioids for chronic nonmalignant pain.

Effectiveness of ketamine as an adjuvant to opioid-based therapy in decreasing pain associated with opioid tolerance in adults undergoing orthopedic surgery: a systematic review protocol.

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Bennett, Marsha; Bonanno, Laura; Kuhn, William

2016-10-01

The objective of this systematic review is to examine the best available evidence on the clinical effectiveness of ketamine as an adjuvant to opioid-based therapy versus opioid-based therapy alone in decreasing perioperative pain associated with opioid tolerance in adult patients, aged 18-70 years, undergoing orthopedic surgical procedures.The following question guides the systematic review: does the administration of ketamine as an adjuvant to opioid-based therapy, compared to opioid-based therapy alone, improve perioperative pain relief in opioid-tolerant adult patients undergoing orthopedic surgical procedures?

Chronic Pain, Chronic Opioid Addiction: a Complex Nexus.

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Salsitz, Edwin A

2016-03-01

Over the past two decades, there has been a significant increase in the prescribing of opioids, with associated increases in opioid addiction and overdose deaths. This article reviews the evidence for the effectiveness and risk of developing an opioid use disorder (OUD) in those patients treated with chronic opioid therapy (COT) for chronic non-cancer pain (CNCP). Rates of development of OUD range from 0-50 %, and aberrant drug related behaviors (ADRBs) are reported to be 20 %. Health care providers must properly assess, screen, and carefully monitor patients on COT utilizing evidence-based tools.

Opioid-induced preconditioning: recent advances and future perspectives.

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Peart, Jason N; Gross, Eric R; Gross, Garrett J

2005-01-01

Opioids, named by Acheson for compounds with morphine-like actions despite chemically distinct structures, have received much research interest, particularly for their central nervous system (CNS) actions involved in pain management, resulting in thousands of scientific papers focusing on their effects on the CNS and other organ systems. A more recent area which may have great clinical importance concerns the role of opioids, either endogenous or exogenous compounds, in limiting the pathogenesis of ischemia-reperfusion injury in heart and brain. The role of endogenous opioids in hibernation provides tantalizing evidence for the protective potential of opioids against ischemia or hypoxia. Mammalian hibernation, a distinct energy-conserving state, is associated with depletion of energy stores, intracellular acidosis and hypoxia, similar to those which occur during ischemia. However, despite the potentially detrimental cellular state induced with hibernation, the myocardium remains resilient for many months. What accounts for the hypoxia-tolerant state is of great interest. During hibernation, circulating levels of opioid peptides are increased dramatically, and indeed, are considered a "trigger" of hibernation. Furthermore, administration of opioid antagonists can effectively reverse hibernation in mammals. Therefore, it is not surprising that activation of opioid receptors has been demonstrated to preserve cellular status following a hypoxic insult, such as ischemia-reperfusion in many model systems including the intestine [Zhang, Y., Wu, Y.X., Hao, Y.B., Dun, Y. Yang, S.P., 2001. Role of endogenous opioid peptides in protection of ischemic preconditioning in rat small intestine. Life Sci. 68, 1013-1019], skeletal muscle [Addison, P.D., Neligan, P.C., Ashrafpour, H., Khan, A., Zhong, A., Moses, M., Forrest, C.R., Pang, C.Y., 2003. Noninvasive remote ischemic preconditioning for global protection of skeletal muscle against infarction. Am. J. Physiol. Heart Circ

Opioid prescriptions before and after high-energy trauma

DEFF Research Database (Denmark)

Zwisler, Stine T; Hallas, Jesper; Larsen, Morten S

2015-01-01

OBJECTIVE: To describe the legal use of opioids in adult patients before and after high-energy trauma. DESIGN: The study was a retrospective database study. SETTING: Clinical care outside hospitals. PATIENTS: All patients who suffered high-energy trauma and were brought to Odense University...... Hospital (OUH), Denmark, in 2007 and 2008 were retrieved from the trauma database. These patients were linked with data on opioid use from the regional prescription database. In all, 938 patients were included. MAIN OUTCOME MEASURE: Redemption of opioid prescription during the 6 months prior...... to a multitrauma or redemption of two or more prescriptions for opioids 6 months or later after a multitrauma. RESULTS: Of the 938 patients brought to OUH with severe trauma within the study period, 61 patients died (7 percent) and six of these had redeemed prescriptions for opioids within 6 months prior...

Vasopressin facilitates excitatory transmission in slices of the rat dorso-lateral septum.

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Van den Hooff, P; Urban, I J

1990-01-01

The effect of vasopressin on neurons of the rat dorso-lateral septum (DLS) was studied in brain slices with intracellular microelectrodes. Two out of 13 neurons showed a small depolarization, spontaneous activity, and increased input resistances following a 15 min exposure to 10(-6) to 10(-8) M vasopressin (VP). These membrane effects disappeared completely within 3-5 min after the application. The remaining DLS neurons treated with these vasopressin concentrations showed an increase in glutamate-mediated excitatory postsynaptic potentials (EPSPs), evoked by stimulation of the fimbria fibers. As little as 10(-12) MVP increased these EPSPs markedly in nearly 80% of the cells studied. This increase in most of the cells disappeared within 15 min after the application period, whereas the increase in EPSPs induced by 10(-10) M VP outlasted the peptide application period for more than 30 min. Neither the blockade of GABA-ergic synaptic inhibition nor the pre-treatment of the neurons with d(CH2)5-Tyr(Me)-arginine vasopressin or 2-amino-5-phosphonovaleric acid (2-APV), antagonists for the V1 type of vasopressin receptor and NMDA receptors, respectively, interfered with the EPSPs potentiating effect of the peptide. It is concluded that a type of vasopressin receptor other then the V1 type is involved in the long-lasting potentiation of the primarily non-NMDA receptor mediated transmission in DLS neurons.

Methylnaltrexone in the treatment of opioid-induced constipation

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Beverley Greenwood-Van Meerveld

2008-12-01

Full Text Available Beverley Greenwood-Van Meerveld1, Kelly M Standifer21Veterans Affairs Medical Center, Oklahoma Center for Neuroscience, Department of Physiology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA; 2Department of Pharmaceutical Sciences, Oklahoma Center for Neuroscience, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USAAbstract: Constipation is a significant problem related to opioid medications used to manage pain. This review attempts to outline the latest findings related to the therapeutic usefulness of a μ opioid receptor antagonist, methylnaltrexone in the treatment of opioid-induced constipation. The review highlights methylnaltrexone bromide (RelistorTM; Progenics/Wyeth a quaternary derivative of naltrexone, which was recently approved in the United States, Europe and Canada. The Food and Drug Administration in the United States approved a subcutaneous injection for the treatment of opioid bowel dysfunction in patients with advanced illness who are receiving palliative care and when laxative therapy has been insufficient. Methylnaltrexone is a peripherally restricted, μ opioid receptor antagonist that accelerates oral–cecal transit in patients with opioidinduced constipation without reversing the analgesic effects of morphine or inducing symptoms of opioid withdrawal. An analysis of the mechanism of action and the potential benefits of using methylnaltrexone is based on data from published basic research and recent clinical studies.Keywords: methylnaltrexone, constipation, opioid

Healthcare resource use and costs of opioid-induced constipation among non-cancer and cancer patients on opioid therapy

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Søndergaard, Jens; Christensen, Helene Nordahl; Ibsen, Rikke

2017-01-01

-based cohort study including patients ≥18 years of age initiating ≥4 weeks opioid therapy (1998–2012) in Denmark. A measure of OIC was constructed based on data from Danish national health registries, and defined as ≥1 diagnosis of constipation, diverticulitis, mega colon, ileus/subileus, abdominal pain....../acute abdomen or haemorrhoids and/or ≥2 subsequent prescription issues of laxatives. Total healthcare resource utilization and costs (including pharmacy dispense, inpatient-, outpatient-, emergency room- and primary care) were estimated according to OIC status, opioid treatment dosage and length, gender, age...... characteristics of non-cancer OIC patients showed a higher frequency of strong opioid treatment (69% versus 41%), long-term opioid treatment (1189 days versus 584 days), advanced age (73 years versus 61 years), and cardiovascular disease (31% versus 19%) compared to those without OIC (P 

Opioid-use disorder among patients on long-term opioid therapy: impact of final DSM-5 diagnostic criteria on prevalence and correlates

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Boscarino JA

2015-08-01

Full Text Available Joseph A Boscarino,1 Stuart N Hoffman,1 John J Han2 1Center for Health Research, 2Department of Pain Medicine, Geisinger Clinic, Danville, PA, USAAims: Previously, we estimated the prevalence and risk factors for prescription opioid-use disorder among outpatients on opioid therapy using the Diagnostic and Statistical Manual of Mental Disorders (DSM-5 and DSM-4 criteria. However, at the time, the DSM-5 criteria were not finalized. In the current study, we analyzed these data using the final DSM-5 criteria and compared these results.Methods: Using electronic records from a large US health care system, we identified outpatients receiving five or more prescription orders for opioid therapy in the past 12 months for noncancer pain (mean prescription orders =10.72; standard deviation =4.96. In 2008, we completed diagnostic interviews with 705 of these patients using the DSM-4 criteria. In the current study, we reassessed these results using the final DSM-5 criteria.Results: The lifetime prevalence of DSM-5 opioid-use disorders using the final DSM-5 criteria was 58.7% for no or few symptoms (<2, 28.1% for mild symptoms (2–3, 9.7% for moderate symptoms (4–5, and 3.5% for severe symptoms (six or more. Thus, the lifetime prevalence of “any” prescription opioid-use disorder in this cohort was 41.3% (95% confidence interval [CI] =37.6–45.0. A comparison to the DSM-4 criteria indicated that the majority of patients with lifetime DSM-4 opioid dependence were now classified as having mild opioid-use disorder, based on the DSM-5 criteria (53.6%; 95% CI =44.1–62.8. In ordinal logistic regression predicting no/few, mild, moderate, and severe opioid-use disorder, the best predictors were age <65 years, current pain impairment, trouble sleeping, suicidal thoughts, anxiety disorders, illicit drug use, and history of substance abuse treatment.Conclusion: Given the final DSM-5 criteria, including the elimination of tolerance and withdrawal, inclusion of

The effect of STDP temporal kernel structure on the learning dynamics of single excitatory and inhibitory synapses.

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Yotam Luz

Full Text Available Spike-Timing Dependent Plasticity (STDP is characterized by a wide range of temporal kernels. However, much of the theoretical work has focused on a specific kernel - the "temporally asymmetric Hebbian" learning rules. Previous studies linked excitatory STDP to positive feedback that can account for the emergence of response selectivity. Inhibitory plasticity was associated with negative feedback that can balance the excitatory and inhibitory inputs. Here we study the possible computational role of the temporal structure of the STDP. We represent the STDP as a superposition of two processes: potentiation and depression. This allows us to model a wide range of experimentally observed STDP kernels, from Hebbian to anti-Hebbian, by varying a single parameter. We investigate STDP dynamics of a single excitatory or inhibitory synapse in purely feed-forward architecture. We derive a mean-field-Fokker-Planck dynamics for the synaptic weight and analyze the effect of STDP structure on the fixed points of the mean field dynamics. We find a phase transition along the Hebbian to anti-Hebbian parameter from a phase that is characterized by a unimodal distribution of the synaptic weight, in which the STDP dynamics is governed by negative feedback, to a phase with positive feedback characterized by a bimodal distribution. The critical point of this transition depends on general properties of the STDP dynamics and not on the fine details. Namely, the dynamics is affected by the pre-post correlations only via a single number that quantifies its overlap with the STDP kernel. We find that by manipulating the STDP temporal kernel, negative feedback can be induced in excitatory synapses and positive feedback in inhibitory. Moreover, there is an exact symmetry between inhibitory and excitatory plasticity, i.e., for every STDP rule of inhibitory synapse there exists an STDP rule for excitatory synapse, such that their dynamics is identical.

Help, Resources and Information: National Opioids Crisis

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... Search Search Help, Resources and Information National Opioids Crisis Search Search Need Help? Call the National Helpline ... HHS 5-POINT STRATEGY TO COMBAT THE OPIOIDS CRISIS BETTER ADDICTION PREVENTION, TREATMENT, AND RECOVERY SERVICES BETTER ...

Neuraxial opioid-induced pruritus: a review.

LENUS (Irish Health Repository)

Szarvas, Szilvia

2012-02-03

When intrathecal and epidural opioids are administered, pruritus occurs as an unwanted and troublesome side effect. The reported incidence varies between 30% and 100%. The exact mechanisms of neuraxial opioid-induced pruritus remain unclear. Postulated mechanisms include the presence of an "itch center" in the central nervous system, medullary dorsal horn activation, and antagonism of inhibitory transmitters. The treatment of intrathecal opioid-induced pruritus remains a challenge. Many pharmacological therapies, including antihistamines, 5-HT(3)-receptor antagonists, opiate-antagonists, propofol, nonsteroid antiinflammatory drugs, and droperidol, have been studied. In this review, we will summarize pathophysiological and pharmacological advances that will improve understanding and ultimately the management of this troublesome problem.

Incidence of iatrogenic opioid dependence or abuse in patients with pain who were exposed to opioid analgesic therapy: a systematic review and meta-analysis.

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Higgins, C; Smith, B H; Matthews, K

2018-06-01

The prevalence and incidence of chronic conditions, such as pain and opioid dependence, have implications for policy development, resource allocation, and healthcare delivery. The primary objective of the current review was to estimate the incidence of iatrogenic opioid dependence or abuse after treatment with opioid analgesics. Systematic electronic searches utilised six research databases (Embase, Medline, PubMed, Cinahl Plus, Web of Science, OpenGrey). A 'grey' literature search and a reference search of included articles were also undertaken. The PICOS framework was used to develop search strategies and the findings are reported in accordance with the PRISMA Statement. After eligibility reviews of 6164 articles, 12 studies (involving 310 408 participants) were retained for inclusion in the meta-analyses. A random effects model (DerSimonian-Laird method) generated a pooled incidence of opioid dependence or abuse of 4.7%. There was little within-study risk of bias and no significant publication bias; however, substantial heterogeneity was found among study effects (99.78%). Sensitivity analyses indicated that the diagnostic criteria selected for identifying opioid dependence or abuse (Diagnostic Statistical Manual (DSM-IV) vs International Classification of Diseases (ICD-9)) accounted for 20% and duration of exposure to opioid analgesics accounted for 18% of variance in study effects. Longer-term opioid analgesic exposure, and prescription of strong rather than weak opioids, were associated with a significantly lower incidence of opioid dependence or abuse. The incidence of iatrogenic opioid dependence or abuse was 4.7% of those prescribed opioids for pain. Further research is required to confirm the potential for our findings to inform prevention of this serious adverse event. Copyright © 2018 British Journal of Anaesthesia. Published by Elsevier Ltd. All rights reserved.

Influence of intravenous opioid dose on postoperative ileus.

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Barletta, Jeffrey F; Asgeirsson, Theodor; Senagore, Anthony J

2011-07-01

Intravenous opioids represent a major component in the pathophysiology of postoperative ileus (POI). However, the most appropriate measure and threshold to quantify the association between opioid dose (eg, average daily, cumulative, maximum daily) and POI remains unknown. To evaluate the relationship between opioid dose, POI, and length of stay (LOS) and identify the opioid measure that was most strongly associated with POI. Consecutive patients admitted to a community teaching hospital who underwent elective colorectal surgery by any technique with an enhanced-recovery protocol postoperatively were retrospectively identified. Patients were excluded if they received epidural analgesia, developed a major intraabdominal complication or medical complication, or had a prolonged workup prior to surgery. Intravenous opioid doses were quantified and converted to hydromorphone equivalents. Classification and regression tree (CART) analysis was used to determine the dosing threshold for the opioid measure most associated with POI and define high versus low use of opioids. Risk factors for POI and prolonged LOS were determined through multivariate analysis. The incidence of POI in 279 patients was 8.6%. CART analysis identified a maximum daily intravenous hydromorphone dose of 2 mg or more as the opioid measure most associated with POI. Multivariate analysis revealed maximum daily hydromorphone dose of 2 mg or more (p = 0.034), open surgical technique (p = 0.045), and days of intravenous narcotic therapy (p = 0.003) as significant risk factors for POI. Variables associated with increased LOS were POI (p POI and prolonged LOS, particularly when the maximum hydromorphone dose per day exceeds 2 mg. Clinicians should consider alternative, nonopioid-based pain management options when this occurs.

Dynamic inhibition of excitatory synaptic transmission by astrocyte-derived ATP in hippocampal cultures

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Koizumi, Schuichi; Fujishita, Kayoko; Tsuda, Makoto; Shigemoto-Mogami, Yukari; Inoue, Kazuhide

2003-09-01

Originally ascribed passive roles in the CNS, astrocytes are now known to have an active role in the regulation of synaptic transmission. Neuronal activity can evoke Ca2+ transients in astrocytes, and Ca2+ transients in astrocytes can evoke changes in neuronal activity. The excitatory neurotransmitter glutamate has been shown to mediate such bidirectional communication between astrocytes and neurons. We demonstrate here that ATP, a primary mediator of intercellular Ca2+ signaling among astrocytes, also mediates intercellular signaling between astrocytes and neurons in hippocampal cultures. Mechanical stimulation of astrocytes evoked Ca2+ waves mediated by the release of ATP and the activation of P2 receptors. Mechanically evoked Ca2+ waves led to decreased excitatory glutamatergic synaptic transmission in an ATP-dependent manner. Exogenous application of ATP does not affect postsynaptic glutamatergic responses but decreased presynaptic exocytotic events. Finally, we show that astrocytes exhibit spontaneous Ca2+ waves mediated by extracellular ATP and that inhibition of these Ca2+ responses enhanced excitatory glutamatergic transmission. We therefore conclude that ATP released from astrocytes exerts tonic and activity-dependent down-regulation of synaptic transmission via presynaptic mechanisms.

Novel approaches for the treatment of psychostimulant and opioid abuse - focus on opioid receptor-based therapies.

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Bailey, Chris P; Husbands, Stephen M

2014-11-01

Psychostimulant and opioid addiction are poorly treated. The majority of abstinent users relapse back to drug-taking within a year of abstinence, making 'anti-relapse' therapies the focus of much current research. There are two fundamental challenges to developing novel treatments for drug addiction. First, there are three key stimuli that precipitate relapse back to drug-taking: stress, presentation of drug-conditioned cue, taking a small dose of drug. The most successful novel treatment would be effective against all three stimuli. Second, a large number of drug users are poly-drug users: taking more than one drug of abuse at a time. The ideal anti-addiction treatment would, therefore, be effective against all classes of drugs of abuse. In this review, the authors discuss the clinical need and animal models used to uncover potential novel treatments. There is a very broad range of potential treatment approaches and targets currently being examined as potential anti-relapse therapies. These broadly fit into two categories: 'memory-based' and 'receptor-based' and the authors discuss the key targets here within. Opioid receptors and ligands have been widely studied, and research into how different opioid subtypes affect behaviours related to addiction (reward, dysphoria, motivation) suggests that they are tractable targets as anti-relapse treatments. Regarding opioid ligands as novel 'anti-relapse' medication targets, research suggests that a 'non-selective' approach to targeting opioid receptors will be the most effective.

Dynamic excitatory and inhibitory gain modulation can produce flexible, robust and optimal decision-making.

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Ritwik K Niyogi

Full Text Available Behavioural and neurophysiological studies in primates have increasingly shown the involvement of urgency signals during the temporal integration of sensory evidence in perceptual decision-making. Neuronal correlates of such signals have been found in the parietal cortex, and in separate studies, demonstrated attention-induced gain modulation of both excitatory and inhibitory neurons. Although previous computational models of decision-making have incorporated gain modulation, their abstract forms do not permit an understanding of the contribution of inhibitory gain modulation. Thus, the effects of co-modulating both excitatory and inhibitory neuronal gains on decision-making dynamics and behavioural performance remain unclear. In this work, we incorporate time-dependent co-modulation of the gains of both excitatory and inhibitory neurons into our previous biologically based decision circuit model. We base our computational study in the context of two classic motion-discrimination tasks performed in animals. Our model shows that by simultaneously increasing the gains of both excitatory and inhibitory neurons, a variety of the observed dynamic neuronal firing activities can be replicated. In particular, the model can exhibit winner-take-all decision-making behaviour with higher firing rates and within a significantly more robust model parameter range. It also exhibits short-tailed reaction time distributions even when operating near a dynamical bifurcation point. The model further shows that neuronal gain modulation can compensate for weaker recurrent excitation in a decision neural circuit, and support decision formation and storage. Higher neuronal gain is also suggested in the more cognitively demanding reaction time than in the fixed delay version of the task. Using the exact temporal delays from the animal experiments, fast recruitment of gain co-modulation is shown to maximize reward rate, with a timescale that is surprisingly near the

Opioid interruptions, pain, and withdrawal symptoms in nursing home residents.

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Redding, Sarah E; Liu, Sophia; Hung, William W; Boockvar, Kenneth S

2014-11-01

Interruptions in opioid use have the potential to cause pain relapse and withdrawal symptoms. The objectives of this study were to observe patterns of opioid interruption during acute illness in nursing home residents and examine associations between interruptions and pain and withdrawal symptoms. Patients from 3 nursing homes in a metropolitan area who were prescribed opioids were assessed for symptoms of pain and withdrawal by researchers blinded to opioid dosage received, using the Brief Pain Inventory Scale and the Clinical Opioid Withdrawal Scale, respectively, during prespecified time periods. The prespecified time periods were 2 weeks after onset of acute illness (eg, urinary tract infection), and 2 weeks after hospital admission and nursing home readmission, if they occurred. Opioid dosing was recorded and a significant interruption was defined as a complete discontinuation or a reduction in dose of >50% for ≥1 day. The covariates age, sex, race, comorbid conditions, initial opioid dose, and initial pain level were recorded. Symptoms pre- and post-opioid interruptions were compared and contrasted with those in a group without opioid interruptions. Sixty-six patients receiving opioids were followed for a mean of 10.9 months and experienced a total of 104 acute illnesses. During 64 (62%) illnesses, patients experienced any reduction in opioid dosing, with a mean (SD) dose reduction of 63.9% (29.9%). During 39 (38%) illnesses, patients experienced a significant opioid interruption. In a multivariable model, residence at 1 of the 3 nursing homes was associated with a lower risk of interruption (odds ratio = 0.073; 95% CI, 0.009 to 0.597; P pain score (difference -0.50 [2.66]; 95% CI, -3.16 to 2.16) and withdrawal score (difference -0.91 [3.12]; 95% CI, -4.03 to 2.21) after the interruption as compared with before interruption. However, when compared with patients without interruptions, patients with interruptions experienced larger increases in pain scores

Comparison of periodontal manifestations in amphetamine and opioids' consumers

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Masoome Eivazi

2016-03-01

Full Text Available Background: Drug abuse is one of the most important etiologic and deteriorating factors in periodontal disease. Amphetamines and opioids, the most commonly used drugs worldwide, play an important role in this regard. The aim of this study was to compare the periodontal status of amphetamines and opioids consumers in Kermanshah city, Iran in 1393. Methods: Three drug rehabilitation clinics were selected randomly in Kermanshah. According to inclusion and exclusion criteria, 20 amphetamine consumers and 20 opioid consumers were selected randomly and participated in this study. A questionnaire for drug use and periodontal variables was designed. The collected data were entered into SPSS-18 software and Mann-Whitney and t-test were used for statistical analysis. Results: Pocket depth, gingival index and gingival bleeding in amphetamines users were more than those in opioids consumers (P<0.021. Plaque index and gingival recession in opioids users were more than those of amphetamines consumers (P<0.001. The number of periodontal disease cases in amphetamines group were 13 persons (65% and in opioids group 8 persons (40%. Conclusion: Our study showed that periodontal hygine in amphetamine consumers was worse than opioid consumers.

Opioid-use disorder among patients on long-term opioid therapy: impact of final DSM-5 diagnostic criteria on prevalence and correlates

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Boscarino, Joseph A; Hoffman, Stuart N; Han, John J

2015-01-01

Aims Previously, we estimated the prevalence and risk factors for prescription opioid-use disorder among outpatients on opioid therapy using the Diagnostic and Statistical Manual of Mental Disorders (DSM)-5 and DSM-4 criteria. However, at the time, the DSM-5 criteria were not finalized. In the current study, we analyzed these data using the final DSM-5 criteria and compared these results. Methods Using electronic records from a large US health care system, we identified outpatients receiving five or more prescription orders for opioid therapy in the past 12 months for noncancer pain (mean prescription orders =10.72; standard deviation =4.96). In 2008, we completed diagnostic interviews with 705 of these patients using the DSM-4 criteria. In the current study, we reassessed these results using the final DSM-5 criteria. Results The lifetime prevalence of DSM-5 opioid-use disorders using the final DSM-5 criteria was 58.7% for no or few symptoms (DSM-5 criteria (53.6%; 95% CI =44.1–62.8). In ordinal logistic regression predicting no/few, mild, moderate, and severe opioid-use disorder, the best predictors were age DSM-5 criteria, including the elimination of tolerance and withdrawal, inclusion of craving and abuse symptoms, and introduction of a new graded severity classification, the prevalence of opioid-use disorders has changed, while many of the DSM-4 risk factors for opioid dependence were similar. To our knowledge, this is one of the first studies to compare the final results for DSM-5 versus DSM-4 prescription opioid-use disorders among a high-risk patient population. PMID:26316838

Neurobiology of opioid withdrawal: Role of the endothelin system.

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Bhalla, Shaifali; Andurkar, Shridhar V; Gulati, Anil

2016-08-15

Morphine and oxycodone are potent opioid analgesics most commonly used for the management of moderate to severe acute and chronic pain. Their clinical utility is limited by undesired side effects like analgesic tolerance, dependence, and withdrawal. We have previously demonstrated that endothelin-A (ETA) receptor antagonists potentiate opioid analgesia and eliminate analgesic tolerance. Mechanistically, G proteins and regulatory proteins such as β-arrestins have shown to play an important role in mediating opioid tolerance, dependence, and withdrawal. Recently, the involvement of central ET mechanisms in opioid withdrawal was investigated. ETA receptor antagonist was shown to block majority of the signs and symptoms associated with opioid withdrawal. This review focuses on ET as one of the potential novel strategies to manage the challenge of opioid withdrawal. An overview of additional players in this process (G proteins and β-arrestin2), and the possible therapeutic implications of these findings are presented. Copyright © 2016 Elsevier Inc. All rights reserved.

Is tapentadol different from classical opioids? A review of the evidence.

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Langford, Richard M; Knaggs, Roger; Farquhar-Smith, Paul; Dickenson, Anthony H

2016-11-01

Tapentadol is a single molecule able to deliver analgesia by two distinct mechanisms, a feature which differentiates it from many other analgesics. Pre-clinical data demonstrate two mechanisms of action: mu-opioid receptor agonist activity and noradrenaline re-uptake inhibition. From these, one may predict that tapentadol would be applicable across a broad spectrum of pain from nociceptive to neuropathic. The evidence in animal models suggests that norepinephrine re-uptake inhibition (NRI) is a key mechanism and may even predominate over opioid actions in chronic (and especially neuropathic) pain states, reinforcing that tapentadol is different to classical opioids and may, therefore, be an a priori choice for the treatment of neuropathic and mixed pain. The clinical studies and subsequent practice experience and surveillance support the concept of opioid and non-opioid mechanisms of action. The reduced incidence of some of the typical opioid-induced side effects, compared to equianalgesic doses of classical opioids, supports the hypothesis that tapentadol analgesia is only partially mediated by opioid agonist mechanisms. Both the pre-clinical and clinical profiles appear to be differentiated from those of classical opioids.

Primary care for opioid use disorder

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Mannelli P

2016-08-01

Full Text Available Paolo Mannelli,1 Li-Tzy Wu1–41Department of Psychiatry and Behavioral Sciences, 2Department of Medicine, 3Duke Clinical Research Institute, Duke University Medical Center, 4Center for Child and Family Policy, Sanford School of Public Policy, Duke University, Durham, NC, USARecent reports on prescription opioid misuse and abuse have described unprecedented peaks of a national crisis and the only answer is to expand prevention and treatment, including different levels of care.1 Nonetheless, concerns remain about the ability of busy primary care settings to manage problem opioid users along with other patients. In particular, proposed extensions of buprenorphine treatment, a critically effective intervention for opioid use disorder (OUD, are cautiously considered due to the potential risk of misuse or abuse.2 General practitioners are already facing this burden daily in the treatment of chronic pain, and expert supervision and treatment model adjustment are needed to help improve outcomes. Approximately 20% of patients in primary care have noncancer pain symptoms, with most of them receiving opioid prescriptions by their physicians, and their number is increasing.3 Pain diagnoses are comparable in severity to those of tertiary centers and are complicated by significant psychiatric comorbidity, with a measurable lifetime risk of developing OUD.4,5 Some primary care physicians report frustration about opioid abuse and diversion by their patients; support from pain specialists would improve their competence, the quality f their performance, and the ability to identify patients at risk of opioid misuse.6 Thus, buprenorphine treatment should not be adding to a complex clinical scenario. To this end, the promising models of care emphasize the integration of medical with psychological and pharmacological expertise for the management of OUD. 

Desipramine in opioid-dependent cocaine abusers maintained on buprenorphine vs methadone.

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Oliveto, A H; Feingold, A; Schottenfeld, R; Jatlow, P; Kosten, T R

1999-09-01

Cocaine abuse occurs in 40% to 60% of patients entering opioid maintenance treatment, and effective pharmacotherapies are needed for this combined dependence. This 13-week, randomized, double-blind, placebo-controlled trial evaluated the efficacy of desipramine hydrochloride (0 or 150 mg/d) plus buprenorphine hydrochloride (12 mg/d) or methadone hydrochloride (65 mg/d) in 180 opioid-dependent cocaine abusers (124 men, 56 women). Supervised urine samples were obtained thrice weekly, and self-reported cocaine and heroin use was reported once weekly. Desipramine plasma levels were determined at weeks 4 and 10. In men, opioid abstinence was increased more rapidly over time when treated with methadone than with buprenorphine, whereas cocaine abstinence was increased more with buprenorphine than with methadone. In women, opioid abstinence was increased the least rapidly when treated with buprenorphine plus placebo, while cocaine abstinence was increased more rapidly over time when treated with methadone than with buprenorphine. Regardless of sex or opioid medication, desipramine increased opioid and cocaine abstinence more rapidly over time than placebo. Self-reported opioid use confirmed these findings. Desipramine plasma levels were higher in women than in men, particularly those on buprenorphine maintenance. Higher desipramine plasma levels were associated with greater opioid, but not cocaine, abstinence. Desipramine may be a useful adjunctive medication in facilitating opioid and cocaine abstinence in opioid-maintained patients. The efficacy of opioid medications to treat opioid or cocaine dependence may differ by sex. These findings highlight the importance of including sex as a factor when examining treatment outcome in these types of trials.

3-pyrazolone analogues of the 3-isoxazolol metabotropic excitatory amino acid receptor agonist homo-AMPA. Synthesis and pharmacological testing

DEFF Research Database (Denmark)

Zimmermann, D.; Janin, Y.L.; Brehm, L.

1999-01-01

the terminal carboxyl group has been replaced by various bioisosteric groups, such as phosphonic acid or 3-isoxazolol groups, have been shown to interact selectively with different subtypes of mGlu receptors. In this paper we report the synthesis of the 3-pyrazolone bioisosteres of a-AA, compounds (RS)-2-amino......-4-(1,2-dihydro-5-methyl-3-oxo-3H-pyrazol-4-yl)butyric acid (1) and (RS)-2-amino-4-(1,2-dihydro-1,5-dimethyl-3-oxo-3H-pyrazol-4-yl)butyric acid (2). At a number of steps in the reaction sequences used, the reactions took unexpected courses and provided products which could not be transformed......We have previously shown that the higher homologue of (S)-glutamic acid [(S)-Glu], (S)-a-aminoadipic acid [(S)-a-AA] is selectively recognized by the mGlu and mGlu subtypes of the family of metabotropic glutamic acid (mGlu) receptors. Furthermore, a number of analogues of (S)-a-AA, in which...

Evolving paradigms in the treatment of opioid-induced bowel dysfunction.

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Poulsen, Jakob Lykke; Brock, Christina; Olesen, Anne Estrup; Nilsson, Matias; Drewes, Asbjørn Mohr

2015-11-01

In recent years prescription of opioids has increased significantly. Although effective in pain management, bothersome gastrointestinal adverse effects are experienced by a substantial proportion of opioid-treated patients. This can lead to difficulties with therapy and subsequently inadequate pain relief. Collectively referred to as opioid-induced bowel dysfunction, these adverse effects are the result of binding of exogenous opioids to opioid receptors in the gastrointestinal tract. This leads to disturbance of three important gastrointestinal functions: motility, coordination of sphincter function and secretion. In the clinic this manifests in a wide range of symptoms such as reflux, bloating, abdominal cramping, hard, dry stools, and incomplete evacuation, although the most known adverse effect is opioid-induced constipation. Traditional treatment with laxatives is often insufficient, but in recent years a number of novel pharmacological approaches have been introduced. In this review the pathophysiology, symptomatology and prevalence of opioid-induced bowel dysfunction is presented along with the benefits and caveats of a suggested consensus definition for opioid-induced constipation. Finally, traditional treatment is appraised and compared with the latest pharmacological developments. In conclusion, opioid antagonists restricted to the periphery show promising results, but use of different definitions and outcome measures complicate comparison. However, an international working group has recently suggested a consensus definition for opioid-induced constipation and relevant outcome measures have also been proposed. If investigators within this field adapt the suggested consensus and include symptoms related to dysfunction of the upper gut, it will ease comparison and be a step forward in future research.

Opioid pharmaceuticals and addiction: the issues, and research directions seeking solutions.

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Walwyn, Wendy M; Miotto, Karen A; Evans, Christopher J

2010-05-01

There are few pharmaceuticals superior to opiates for the treatment of pain. However, with concerns of addiction, withdrawal and questionable efficacy for all types of pain, these compounds are far from a magical panacea for pain-relief. As it is unlikely that other classes of compounds will supersede the opioids in the very near future, it is important to both optimize current opioid therapies and curb the astounding diversion of opioids from their intended analgesic use to non-medical abuse. In optimizing opioid therapeutics it is necessary to enhance the clinical awareness of the benefits of treating pain and combine this with aggressive strategies to reduce diversion for non-medical use. At the heart of the issue of opioid misuse is the role of opioid systems in the reward circuitry, and the adaptive processes associated with repetitive opioid use that manifest during withdrawal. Emerging pharmacological insights of opioid receptors will be reviewed that provide future hope for developing opioid-based analgesics with reduced addictive properties and perhaps, reduced opponent processes. In addition, with the increased understanding of nociceptive circuitry and the molecules involved in transmitting pain, new therapeutic targets have become evident that may result in effective analgesics either alone or in combination with current opioid therapies.

Structure of the [delta]-opioid receptor bound to naltrindole

Energy Technology Data Exchange (ETDEWEB)

Granier, Sébastien; Manglik, Aashish; Kruse, Andrew C.; Kobilka, Tong Sun; Thian, Foon Sun; Weis, William I.; Kobilka, Brian K. (Stanford-MED)

2012-07-11

The opioid receptor family comprises three members, the {mu}-, {delta}- and {kappa}-opioid receptors, which respond to classical opioid alkaloids such as morphine and heroin as well as to endogenous peptide ligands like endorphins. They belong to the G-protein-coupled receptor (GPCR) superfamily, and are excellent therapeutic targets for pain control. The {delta}-opioid receptor ({delta}-OR) has a role in analgesia, as well as in other neurological functions that remain poorly understood. The structures of the {mu}-OR and {kappa}-OR have recently been solved. Here we report the crystal structure of the mouse {delta}-OR, bound to the subtype-selective antagonist naltrindole. Together with the structures of the {mu}-OR and {kappa}-OR, the {delta}-OR structure provides insights into conserved elements of opioid ligand recognition while also revealing structural features associated with ligand-subtype selectivity. The binding pocket of opioid receptors can be divided into two distinct regions. Whereas the lower part of this pocket is highly conserved among opioid receptors, the upper part contains divergent residues that confer subtype selectivity. This provides a structural explanation and validation for the 'message-address' model of opioid receptor pharmacology, in which distinct 'message' (efficacy) and 'address' (selectivity) determinants are contained within a single ligand. Comparison of the address region of the {delta}-OR with other GPCRs reveals that this structural organization may be a more general phenomenon, extending to other GPCR families as well.

Development and preliminary validation of the Opioid Abuse Risk Screener

Directory of Open Access Journals (Sweden)

Patricia Henrie-Barrus

2016-05-01

Full Text Available Prescription opioid drug abuse has reached epidemic proportions. Individuals with chronic pain represent a large population at considerable risk of abusing opioids. The Opioid Abuse Risk Screener was developed as a comprehensive self-administered measure of potential risk that includes a wide range of critical elements noted in the literature to be relevant to opioid risk. The creation, refinement, and preliminary modeling of the item pool, establishment of preliminary concurrent validity, and the determination of the factor structure are presented. The initial development and validation of the Opioid Abuse Risk Screener shows promise for effective risk stratification.

Parallel prefrontal pathways reach distinct excitatory and inhibitory systems in memory-related rhinal cortices.

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Bunce, Jamie G; Zikopoulos, Basilis; Feinberg, Marcia; Barbas, Helen

2013-12-15

To investigate how prefrontal cortices impinge on medial temporal cortices we labeled pathways from the anterior cingulate cortex (ACC) and posterior orbitofrontal cortex (pOFC) in rhesus monkeys to compare their relationship with excitatory and inhibitory systems in rhinal cortices. The ACC pathway terminated mostly in areas 28 and 35 with a high proportion of large terminals, whereas the pOFC pathway terminated mostly through small terminals in area 36 and sparsely in areas 28 and 35. Both pathways terminated in all layers. Simultaneous labeling of pathways and distinct neurochemical classes of inhibitory neurons, followed by analyses of appositions of presynaptic and postsynaptic fluorescent signal, or synapses, showed overall predominant association with spines of putative excitatory neurons, but also significant interactions with presumed inhibitory neurons labeled for calretinin, calbindin, or parvalbumin. In the upper layers of areas 28 and 35 the ACC pathway was associated with dendrites of neurons labeled with calretinin, which are thought to disinhibit neighboring excitatory neurons, suggesting facilitated hippocampal access. In contrast, in area 36 pOFC axons were associated with dendrites of calbindin neurons, which are poised to reduce noise and enhance signal. In the deep layers, both pathways innervated mostly dendrites of parvalbumin neurons, which strongly inhibit neighboring excitatory neurons, suggesting gating of hippocampal output to other cortices. These findings suggest that the ACC, associated with attention and context, and the pOFC, associated with emotional valuation, have distinct contributions to memory in rhinal cortices, in processes that are disrupted in psychiatric diseases. Copyright © 2013 Wiley Periodicals, Inc.

Comparative Analysis of Inpatient Costs for Obstetrics and Gynecology Surgery Patients Treated With IV Acetaminophen and IV Opioids Versus IV Opioid-only Analgesia for Postoperative Pain.

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Hansen, Ryan N; Pham, An T; Lovelace, Belinda; Balaban, Stela; Wan, George J

2017-10-01

Recovery from obstetrics and gynecology (OB/GYN) surgery, including hysterectomy and cesarean section delivery, aims to restore function while minimizing hospital length of stay (LOS) and medical expenditures. Our analyses compare OB/GYN surgery patients who received combination intravenous (IV) acetaminophen and IV opioid analgesia with those who received IV opioid-only analgesia and estimate differences in LOS, hospitalization costs, and opioid consumption. We performed a retrospective analysis of the Premier Database between January 2009 and June 2015, comparing OB/GYN surgery patients who received postoperative pain management with combination IV acetaminophen and IV opioids with those who received only IV opioids starting on the day of surgery and continuing up to the second postoperative day. We performed instrumental variable 2-stage least-squares regressions controlling for patient and hospital covariates to compare the LOS, hospitalization costs, and daily opioid doses (morphine equivalent dose) of IV acetaminophen recipients with that of opioid-only analgesia patients. We identified 225 142 OB/GYN surgery patients who were eligible for our study of whom 89 568 (40%) had been managed with IV acetaminophen and opioids. Participants averaged 36 years of age and were predominantly non-Hispanic Caucasians (60%). Multivariable regression models estimated statistically significant differences in hospitalization cost and opioid use with IV acetaminophen associated with $484.4 lower total hospitalization costs (95% CI = -$760.4 to -$208.4; P = 0.0006) and 8.2 mg lower daily opioid use (95% CI = -10.0 to -6.4), whereas the difference in LOS was not significant, at -0.09 days (95% CI = -0.19 to 0.01; P = 0.07). Compared with IV opioid-only analgesia, managing post-OB/GYN surgery pain with the addition of IV acetaminophen is associated with decreased hospitalization costs and reduced opioid use.

Yiguanjian cataplasm attenuates opioid dependence in a mouse

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Gao, Shuai; Gao, Hong; Fan, Yuchen; Zhang, Guanghua; Sun, Fengkai; Zhao, Jing; Li, Feng; Yang, Yang; Wang, Kai

2016-08-01

To investigate the effect of Yiguanjian (YGJ) cataplasm on the development of opioid dependence in a mouse model of naloxone-induced opioid withdrawal syndrome. One hundred Swiss albino mice, of equal male to female ratio, were randomly and equally divided into 10 groups. A portion (3 cm2) of the backside hair of the mice was removed 1 day prior to the experiment. Morphine (5 mg/kg) was intraperitoneally administered twice daily for 5 days. YGJ cataplasm was prepared and pasted on the bare region of the mice immediately before morphine administration on day 3 and subsequently removed at the end day 5. On day 6, naloxone (8 mg/kg) was intraperitoneally injected to precipitate opioid withdrawal syndrome. Behavioral observation was performed in two 30-min phases immediately after naloxone injection. The YGJ cataplasm significantly and dose-dependently attenuated morphine-naloxone- induced experimental opioid withdrawal, in terms of withdrawal severity score and the frequencies of jumping, rearing, forepaw licking, and circling behaviors. However, YGJ cataplasm treatment did not alter the acute analgesic effect of morphine. YGJ cataplasm could attenuate opioid dependence and its associated withdrawal symptoms. Therefore, YGJ cataplasm could serve as a potential therapy for opioid addiction in the future.

Changes in misuse and abuse of prescription opioids following implementation of Extended-Release and Long-Acting Opioid Analgesic Risk Evaluation and Mitigation Strategy.

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Bucher Bartelson, Becki; Le Lait, M Claire; Green, Jody L; Cepeda, M Soledad; Coplan, Paul M; Maziere, Jean-Yves; Wedin, Gregory P; Dart, Richard C

2017-09-01

An unintended consequence of extended-release (ER) and long-acting (LA) prescription opioids is that these formulations can be more attractive to abusers than immediate-release (IR) formulations. The US Food and Drug Administration recognized these risks and approved the ER/LA Opioid Analgesic Risk Evaluation and Mitigation Strategy (ER/LA REMS), which has a goal of reducing opioid misuse and abuse and their associated consequences. The primary objective of this analysis is to determine whether ER/LA REMS implementation was associated with decreased reports of misuse and abuse. Data from the Researched Abuse, Diversion and Addiction-Related Surveillance (RADARS(R)) System Poison Center Program were utilized. Poison center cases are assigned a reason for exposure, a medical outcome, and a level of health care received. Rates adjusted for population and drug utilization were analyzed over time. RADARS System Poison Center Program data indicate a notable decrease in ER/LA opioid rates of intentional abuse and misuse as well as major medical outcomes or hospitalizations following implementation of the ER/LA REMS. While similar decreases were observed for the IR prescription opioid group, the decreasing rate for the ER/LA opioids exceeded the decreasing rates for the IR prescription opioids and was distinctly different than that for the prescription stimulants, indicating that the ER/LA REMS program may have had an additional effect on decreases in opioid abuse and intentional misuse beyond secular trends. Copyright © 2017 John Wiley & Sons, Ltd.

Association of childhood abuse and prescription opioid use in early adulthood.

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Austin, Anna E; Shanahan, Meghan E; Zvara, Bharathi J

2018-01-01

Previous research has examined the association of childhood abuse with opioid misuse and dependence in adulthood. However, little research has focused specifically on prescription opioids, and no studies have examined associations with prescription opioid use, a potential pathway to later opioid misuse and dependence. The aim of the present study was to examine the association of childhood emotional, physical, and sexual abuse with prescription opioid use in early adulthood. We used data from Waves I (12-18years) and IV (24-32years) of the National Longitudinal Study of Adolescent to Adult Health. At Wave IV, respondents reported experiences of childhood abuse occurring prior to age 18years and prescription opioid use in the last four weeks. We conducted multivariable logistic regression to examine associations of childhood abuse with recent prescription opioid use. In multivariable models adjusted for respondent sex, race/ethnicity, age, and socioeconomic status, childhood emotional abuse (OR=1.57, 95% CI 1.29, 1.90), physical abuse (OR=1.46, 95% CI 1.14, 1.87), and any childhood abuse (OR=1.51, 95% CI 1.24, 1.82) were significantly associated with recent prescription opioid use. Given continued increases in prescription opioid use and opioid-related morbidity and mortality in the U.S., understanding upstream social and environmental factors associated with prescription opioid use is important to strengthening and expanding current prevention and intervention strategies. Future research is needed to examine factors potentially mediating the association between childhood abuse and prescription opioid use in order to provide additional insights for prevention and intervention efforts. Copyright © 2017 Elsevier Ltd. All rights reserved.

Prescription opioids for occupational injury: results from workers' compensation claims records.

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Berecki-Gisolf, Janneke; Collie, Alex; McClure, Roderick J

2014-09-01

The objective of this study is to identify the prevalence of opioid prescription use in an Australian workers' compensation population and assess predictors of long-term use. Retrospective administrative data analysis. WorkSafe Victoria (Australia) workers' compensation. Workers with a workers' compensation claim were included if the injury/illness started in 2008 or 2009 (N = 54,931). Claim payments records dating up to 2 years postinjury were analyzed to determine receipt of prescription opioids. Long-term use was defined as use of any opioid beyond 1 year postinjury. Within the follow-up period, 8,933 (16.3%) workers claimed prescription opioids: 10.0% claimed opioids in the first year only, and 6.3% claimed opioids beyond the first year. The most commonly received opioids were codeine (10.4%), oxycodone (7.5%), and tramadol (5.0%). Dextropropoxyphene, which is considered unsafe in many countries because of potentially fatal side effects, was used by 1.9% of injured workers. Progression to long-term use of opioids was common (N = 3,446; 39%): age (35-64 years; the association with age followed an inverse U-shaped curve), women, laborers, lower socioeconomic status, greater work disability, and greater hospital expense were associated with opioid use beyond the first year postinjury. Prescription opioid use for workplace injury in Australia is common but not as common as reports from U.S. workers' compensation schemes. The type of opioid and number of repeat prescriptions are factors that should be carefully considered by practitioners prescribing opioids to injured workers: progression to long-term use is common and not fully explained by injury severity. Wiley Periodicals, Inc.

Benzodiazepines and Opioid

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... Alcohol Club Drugs Cocaine Fentanyl Hallucinogens Inhalants Heroin Marijuana MDMA (Ecstasy/Molly) Methamphetamine Opioids Over-the-Counter Medicines Prescription Medicines Steroids (Anabolic) Synthetic Cannabinoids (K2/Spice) Synthetic Cathinones (Bath Salts) Tobacco/ ...

Opioid Overdose Crisis

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... Alcohol Club Drugs Cocaine Fentanyl Hallucinogens Inhalants Heroin Marijuana MDMA (Ecstasy/Molly) Methamphetamine Opioids Over-the-Counter Medicines Prescription Medicines Steroids (Anabolic) Synthetic Cannabinoids (K2/Spice) Synthetic Cathinones (Bath Salts) Tobacco/ ...

Undertreatment of pain and low use of opioids in Latin America.

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García, César Amescua; Santos Garcia, Joao Batista; Rosario Berenguel Cook, María Del; Colimon, Frantz; Flores Cantisani, José Alberto; Guerrero, Carlos; Rocío Guillén Núnez, María Del; Hernández Castro, John Jairo; Kraychete, Durval Campos; Lara-Solares, Argelia; Lech, Osvandré; Rico Pazos, María Antonieta; Gallegos, Manuel Sempértegui; Marcondes, Lizandra Pattaro

2018-05-01

Pain is highly prevalent among the adult Latin American population. However, many patients with moderate to severe pain do not have access to effective pain management with opioids due to limited access to healthcare, overuse of nonopioid analgesics, regulatory barriers and lack of appropriate information about opioids. There is scarce training on use of opioids among physicians and other healthcare providers, which leads to misconceptions, mainly related to a fear of prescribing opioids. Although opioids are safe and effective drugs for the treatment of moderate to severe chronic pain, the use of opioids in Latin American nations is clearly below standards compared with developed countries.

The opioid receptors of the rat periaqueductal gray

Energy Technology Data Exchange (ETDEWEB)

Fedynyshyn, J.P.

1989-01-01

The opioid binding characteristics of the rat (PAG) and the signal transduction mechanisms of the opioid receptors were examined with in vitro radioligand binding, GTPase, adenylyl cyclase, and inositol phosphate assays. The nonselective ligand {sup 3}H-ethylketocyclazocine (EKC), the {mu} and {delta} selective ligand {sup 3}H-(D-Ala{sup 2}, D-Leu{sup 5}) enkephalin (DADLE), the {mu} selective ligand {sup 3}H-(D-Ala{sup 2}, N-methyl Phe{sup 4}, Glyol{sup 5}) enkephalin (DAGO), and the {delta} selective ligand {sup 3}H-(D-Pen{sup 2}, D-Pen{sup 5}) enkephalin (DPDPE) were separately used as tracer ligands to label opioid binding sites in rat PAG enriched P{sub 2} membrane in competition with unlabeled DADLE, DAGO, DPDPE, or the {kappa} selective ligand trans-3,4-dichloro-N-(2-(1-pyrrolidinyl)cyclohexyl)benzeneacetamide, methane sulfonate, hydrate (U50, 488H). Only {mu} selective high affinity opioid binding was observed. No high affinity {delta} or {kappa} selective binding was detected. {sup 3}H-DAGO was used as a tracer ligand to label {mu} selective high affinity opioid binding sites in PAG enriched P{sub 2} membrane in competition with unlabeled {beta}-endorphin, dynorphin A (1-17), BAM-18, methionine enkephalin, dynorphin A (1-8), and leucine enkephalin. Of these endogenous opioid peptides only those with previously reported high affinity {mu} type opioid binding activity competed with {sup 3}H-DAGO for binding sites in rat PAG enriched P{sub 2} membrane with affinities similar to that of unlabeled DAGO.

Endogenous opioid peptides as neurotransmitters in the rat hippocampus

International Nuclear Information System (INIS)

Neumaier, J.F.

1989-01-01

The role of endogenous opioid peptides as neurotransmitters in the rat hippocampus was investigated by using extracellular recording and radioligand binding techniques in the hippocampal slice preparation. Synaptic conductances from endogenously released opioid peptides have been difficult to detect. This problem was approach by designing a novel assay of opioid peptide release, in which release was detected by measuring binding competition between endogenous opioids and added radioligand. Membrane depolarization displaced [ 3 H]-diprenorphine binding in a transient, calcium-dependent, and peptidase-sensitive manner. Autoradiographic localization of the sites of [ 3 H]-diprenorphine binding displacement showed that significant opioid peptide release and receptor occupancy occurred in each major subregion of the hippocampal slices. This assay method can not be used to define optimal electrical stimulation conditions for releasing endogenous opioids. The binding displacement method was extended to the study of the sigma receptor. Depolarization of hippocampal slices was found to reduce the binding of the sigma-selective radioligand [ 3 H]-ditolylguanidine in a transient and calcium-dependent manner with no apparent direct effects on sigma receptor affinity

Preference or fat? Revisiting opioid effects on food intake.

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Taha, Sharif A

2010-07-14

It is well established that opioid signaling in the central nervous system constitutes a powerful stimulus for food intake. The role of opioids in determining food preference, however, is less well defined. Opioids have been proposed to promote intake of preferred foods, or, alternatively, to preferentially increase consumption of fat. In the present manuscript, I comprehensively review results from previous studies investigating this issue. Data from these studies suggests a mechanism for opioid action that may reconcile the previously proposed hypotheses: opioid effects on food intake do appear to be largely specific for fat consumption, but individual animals' sensitivity to this effect may be dependent on baseline food preferences. In addition, I highlight the possibility that the selectivity of endogenous opioid effects may importantly differ from that of exogenous agonists in the degree to which baseline preferences, rather than macronutrient intake, are altered. The paper represents an invited review by a symposium, award winner or keynote speaker at the Society for the Study of Ingestive Behavior [SSIB] Annual Meeting in Portland, July 2009. 2010 Elsevier Inc. All rights reserved.

Amino Acids in Cerebrospinal Fluid of Patients with Aneurysmal Subarachnoid Haemorrhage: An Observational Study

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Bartosz Sokół

2017-08-01

Full Text Available BackgroundThe authors are aware of only one article investigating amino acid concentrations in cerebrospinal fluid (CSF in patients with ruptured intracranial aneurysms, and this was published 31 years ago. Since then, both management of subarachnoid haemorrhage (SAH and amino acid assay techniques have seen radical alterations, yet the pathophysiology of SAH remains unclear.ObjectiveTo analyse the pattern of concentrations of amino acids and related compounds in patients with different outcomes following aneurysmal SAH.Methods49 CSF samples were collected from 23 patients on days 0–3, 5, and 10 post-SAH. Concentrations of 33 amino acids and related compounds were assayed by liquid chromatography tandem mass spectrometry in patients with good [Glasgow Outcome Scale (GOS 1–3] and poor (GOS 4–5 outcome.ResultsOf the 33 compounds assayed, only hydroxyproline and 3-aminoisobutyric acid appeared not to increase significantly following SAH. In poor outcome patients, we found significantly higher concentrations of aspartic acid (p = 0.038, glutamic acid (p = 0.038, and seven other compounds on days 0–3 post-SAH; glutamic acid (p = 0.041 on day 5 post-SAH, and 2-aminoadipic acid (p = 0.033 on day 10 post-SAH. The most significant correlation with GOS at 3 months was found for aminoadipic acid on day 10 post-SAH (cc = −0.81.ConclusionAneurysmal rupture leads to a generalised increase of amino acids and related compounds in CSF. The patterns differ between good and poor outcome cases. Increased excitatory amino acids are strongly indicative of poor outcome.

Safety of oral dronabinol during opioid withdrawal in humans.

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Jicha, Crystal J; Lofwall, Michelle R; Nuzzo, Paul A; Babalonis, Shanna; Elayi, Samy Claude; Walsh, Sharon L

2015-12-01

Opioid dependence remains a significant public health problem worldwide with only three FDA-approved treatments, all targeting the mu-opioid receptor. Dronabinol, a cannabinoid (CB) 1 receptor agonist, is currently under investigation as a novel opioid withdrawal treatment. This study reports on safety outcomes of dronabinol among adults in opioid withdrawal. Twelve adults physically dependent on short-acting opioids participated in this 5-week within-subject, randomized, double blind, placebo-controlled inpatient study. Volunteers were maintained on oral oxycodone 30 mg qid. Double-blind placebo substitutions occurred for 21 h before each of 7 experimental sessions in order to produce opioid withdrawal. A single oral test dose was administered each session (placebo, oxycodone 30 and 60 mg, dronabinol 5, 10, 20, and 30 mg [decreased from 40 mg]). Heart rate, blood pressure, respiratory outcomes and pupil diameter were assessed repeatedly. Dronabinol 40 mg produced sustained sinus tachycardia accompanied by anxiety and panic necessitating dose reduction to 30 mg. Sinus tachycardia and anxiety also occurred in one volunteer after dronabinol 20mg. Compared to placebo, dronabinol 20 and 30 mg produced significant increases in heart rate beginning 1h after drug administration that lasted approximately 2h (popioid agonist effects (e.g., miosis). Dronabinol 20mg and higher increased heart rate among healthy adults at rest who were in a state of opioid withdrawal, raising concern about its safety. These results have important implications for future dosing strategies and may limit the utility of dronabinol as a treatment for opioid withdrawal. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

The role of the opioid system in alcohol dependence.

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Nutt, David J

2014-01-01

The role of the brain opioid system in alcohol dependence has been the subject of much research for over 25 years. This review explores the evidence: firstly describing the opioid receptors in terms of their individual subtypes, neuroanatomy, neurophysiology and ligands; secondly, summarising emerging data from specific neurochemical, behavioural and neuroimaging studies, explaining the characteristics of addiction with a focus on alcohol dependence and connecting the opioid system with alcohol dependence; and finally reviewing the known literature regarding opioid antagonists in clinical use for alcohol dependence. Further interrogation of how modulation of the opioid system, via use of MOP (mu), DOP (delta) and KOP (kappa) agents, restores the balance of a dysregulated system in alcohol dependence should increase our insight into this disease process and therefore guide better methods for understanding and treating alcohol dependence in the future.

Emerging therapies for patients with symptoms of opioid-induced bowel dysfunction

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Leppert W

2015-04-01

Full Text Available Wojciech Leppert Chair and Department of Palliative Medicine, Poznan University of Medical Sciences, Poznan, Poland Abstract: Opioid-induced bowel dysfunction (OIBD comprises gastrointestinal (GI symptoms, including dry mouth, nausea, vomiting, gastric stasis, bloating, abdominal pain, and opioid-induced constipation, which significantly impair patients’ quality of life and may lead to undertreatment of pain. Traditional laxatives are often prescribed for OIBD symptoms, although they display limited efficacy and exert adverse effects. Other strategies include prokinetics and change of opioids or their administration route. However, these approaches do not address underlying causes of OIBD associated with opioid effects on mostly peripheral opioid receptors located in the GI tract. Targeted management of OIBD comprises purely peripherally acting opioid receptor antagonists and a combination of opioid receptor agonist and antagonist. Methylnaltrexone induces laxation in 50%–60% of patients with advanced diseases and OIBD who do not respond to traditional oral laxatives without inducing opioid withdrawal symptoms with similar response (45%–50% after an oral administration of naloxegol. A combination of prolonged-release oxycodone with prolonged-release naloxone (OXN in one tablet (a ratio of 2:1 provides analgesia with limited negative effect on the bowel function, as oxycodone displays high oral bioavailability and naloxone demonstrates local antagonist effect on opioid receptors in the GI tract and is totally inactivated in the liver. OXN in daily doses of up to 80 mg/40 mg provides equally effective analgesia with improved bowel function compared to oxycodone administered alone in patients with chronic non-malignant and cancer-related pain. OIBD is a common complication of long-term opioid therapy and may lead to quality of life deterioration and undertreatment of pain. Thus, a complex assessment and management that addresses underlying

Network models predict that reduced excitatory fluctuations can give rise to hippocampal network hyper-excitability in MeCP2-null mice.

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Ernest C Y Ho

Full Text Available Rett syndrome is a severe pediatric neurological disorder caused by loss of function mutations within the gene encoding methyl CpG-binding protein 2 (MeCP2. Although MeCP2 is expressed near ubiquitously, the primary pathophysiology of Rett syndrome stems from impairments of nervous system function. One alteration within different regions of the MeCP2-deficient brain is the presence of hyper-excitable network responses. In the hippocampus, such responses exist despite there being an overall decrease in spontaneous excitatory drive within the network. In this study, we generated and used mathematical, neuronal network models to resolve this apparent paradox. We did this by taking advantage of previous mathematical modelling insights that indicated that decreased excitatory fluctuations, but not mean excitatory drive, more critically explain observed changes in hippocampal network oscillations from MeCP2-null mouse slices. Importantly, reduced excitatory fluctuations could also bring about hyper-excitable responses in our network models. Therefore, these results indicate that diminished excitatory fluctuations may be responsible for the hyper-excitable state of MeCP2-deficient hippocampal circuitry.

Analysis of opioid-mediated analgesia in Phase III studies of methylnaltrexone for opioid-induced constipation in patients with chronic noncancer pain

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Webster LR

2015-10-01

Full Text Available Lynn R Webster,1 Darren M Brenner,2 Andrew C Barrett,3 Craig Paterson,3 Enoch Bortey,3 William P Forbes3 1PRA Health Sciences, Salt Lake City, UT, 2Department of Medicine, Northwestern University Feinberg School of Medicine, Chicago, IL, 3Salix, a Division of Valeant Pharmaceuticals North America LLC, Bridgewater, NJ, USA Background: Subcutaneous methylnaltrexone is efficacious and well tolerated for opioid-induced constipation (OIC but may theoretically disrupt opioid-mediated analgesia. Methods: Opioid use, pain intensity, and opioid withdrawal (Objective Opioid Withdrawal Scale [OOWS] and Subjective Opiate Withdrawal Scale [SOWS] scores were reported in a randomized, double-blind trial with an open-label extension (RCT and an open-label trial (OLT evaluating safety in adults with chronic noncancer pain. In the RCT, patients taking ≥50 mg of oral morphine equivalents daily with <3 rescue-free bowel movements weekly received methylnaltrexone 12 mg once daily (n=150, every other day (n=148, or placebo (n=162 for 4 weeks, followed by open-label methylnaltrexone 12 mg (as needed [prn]; n=364 for 8 weeks. In the OLT, patients (n=1,034 on stable opioid doses with OIC received methylnaltrexone 12 mg prn for up to 48 weeks. Results: Minimal fluctuations of median morphine equivalent dose from baseline (BL were observed in the RCT double-blind period (BL, 154.8–161.0 mg/d; range, 137.1–168.0 mg/d, RCT open-label period (BL, 156.3–174.6; range, 144.0–180.0 and OLT (BL, 120 mg/d; range, 117.3–121.1 mg/d. No significant change from BL in pain intensity score occurred in any group at weeks 2 or 4 (both P≥0.1 of the RCT double-blind period, and scores remained stable during the open-label period and in the OLT (mean change, —0.2 to 0.1. Changes from BL in OOWS and SOWS scores during the double-blind period were not significantly impacted by methylnaltrexone exposure at weeks 2 or 4 (P>0.05 for all. Conclusion: Methylnaltrexone did not affect

Predictors of long-term opioid use among chronic nonmalignant pain patients

DEFF Research Database (Denmark)

Hansen, Carrinna; Abrahamsen, Bo

2016-01-01

, socioeconomic and demographic characteristics. Data analysis is ongoing. Conclusions: It is expected that this study will serve as a significant supplement of existing knowledge in the area of opioid consumption among CNP patients in Denmark. In a future perspective of prevention and health promotion......Aims: 1) To determine the distribution and determinants of opioid use among chronic nonmalignant pain(CNP) patients. 2) To identify the patient, treatment and socioeconomic characteristics as determinants for potential risk groups. We hypothesized that CNP patient who use opioids for more than 1...... product using the ATC codes N02AA01-N02AX06. Patients were then classified as either opioid use for more than 1 year(group A), as opioid use for more than 6 months but less than 1 year(group B) and opioid use equal to or less than 6 months(group C). Results: The quantity of sold opioids has been...

Clinical utility of naloxegol in the treatment of opioid-induced constipation.

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Bruner, Heather C; Atayee, Rabia S; Edmonds, Kyle P; Buckholz, Gary T

2015-01-01

Opioids are a class of medications frequently used for the treatment of acute and chronic pain, exerting their desired effects at central opioid receptors. Agonism at peripherally located opioid receptors, however, leads to opioid-induced constipation (OIC), one of the most frequent and debilitating side effects of prolonged opioid use. Insufficient relief of OIC with lifestyle modification and traditional laxative treatments may lead to decreased compliance with opioid regimens and undertreated pain. Peripherally acting mu-opioid receptor antagonists (PAMORAs) offer the reversal of OIC without loss of central pain relief. Until recently, PAMORAs were restricted to subcutaneous route or to narrow patient populations. Naloxegol is the first orally dosed PAMORA indicated for the treatment of OIC in noncancer patients. Studies have suggested its efficacy in patients failing traditional constipation treatments; however, insufficient evidence exists to establish its role in primary prevention of OIC at this time.

Low pain intensity after opioid withdrawal as a first step of a comprehensive pain rehabilitation program predicts long-term nonuse of opioids in chronic noncancer pain.

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Krumova, Elena K; Bennemann, Philipp; Kindler, Doris; Schwarzer, Andreas; Zenz, Michael; Maier, Christoph

2013-09-01

In specialized pain clinics there is an increasing number of patients with severe chronic noncancer pain (CNCP) despite long-term opioid medication. Few clinical studies show short-term pain relief after opioid withdrawal (OW). We have evaluated the relation between pain intensity after OW and long-term opioid nonuse. One hundred two consecutive patients with severe CNCP despite opioid medication (mean treatment duration, 43 mo) reported pain intensity (numerical rating scale, 0 to 10), Pain Disability Index, mood (CES-D), and quality of life (Short Form 36) before, shortly, and 12 to 24 months after inpatient OW. Total opioid withdrawal (n = 78) or significant dose reduction (DR; n = 24, mean reduction, 82%) was performed after individual decision. Opioid intake 12 to 24 months later, respectively dose increase ≥ 100% (DR group), was considered relapse. T tests, multivariable analysis of variance, logistic regression. After OW current pain intensity significantly decreased on an average by 41% (6.4 ± 2.4 vs. 3.8 ± 2.5), maximal and average pain by 18% and 24%, respectively. Twelve to 24 months later 42 patients (41%) relapsed (31 of the total opioid withdrawal group, 6 of the DR group, 5 lost). Patients without later relapse showed significantly lower pain scores than the later relapsed patients already shortly after OW (5.0 ± 2.2 vs. 5.9 ± 2.1) and 12 to 24 months later (5.5 ± 2.4 vs. 6.5 ± 2.0). There was a significant relation between relapse probability and pain intensity immediately after OW. In many patients with severe CNCP, despite opioid medication, sustainable pain relief can be achieved if OW is included in the rehabilitation program. Consequently, we recommend OW for opioid-resistant CNCP before any opioid escalation. Lower pain intensity shortly after OW may predict the long-term opioid nonuse probability.

The influence of propoxyphene withdrawal on opioid use in veterans.

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Hayes, Corey J; Hudson, Teresa J; Phillips, Martha M; Bursac, Zoran; Williams, James S; Austin, Mark A; Edlund, Mark J; Martin, Bradley C

2015-11-01

Our aim is to determine if propoxyphene withdrawal from the US market was associated with opioid continuation, continued chronic opioid use, and secondary propoxyphene-related adverse events (emergency department visits, opioid-related events, and acetaminophen toxicity). Medical service use and pharmacy data from 19/11/08 to 19/11/11 were collected from the national Veterans Healthcare Administration healthcare databases. A quasi-experimental pre-post retrospective cohort design utilizing a historical comparison group provided the study framework. Logistic regression controlling for baseline covariates was used to estimate the effect of propoxyphene withdrawal. There were 24,328 subjects (policy affected n = 10,747; comparison n = 13,581) meeting inclusion criteria. In the policy-affected cohort, 10.6% of users ceased using opioids, and 26.6% stopped chronic opioid use compared with 3.8% and 13.5% in the historical comparison cohort, respectively. Those in the policy-affected cohort were 2.7 (95%CI: 2.5-2.8) and 3.2 (95%CI: 2.9-3.6) times more likely than those in the historical comparison cohort to discontinue chronic opioid and any opioid use, respectively. Changes in adverse events and Emergency Department (ED) visits were not different between policy-affected and historical comparison cohorts (p > 0.05). The withdrawal of propoxyphene-containing products resulted in rapid and virtually complete elimination in propoxyphene prescribing in the veterans population; however, nearly 90% of regular users of propoxyphene switched to an alternate opioid, and three quarters continued to use opioids chronically. Copyright © 2015 John Wiley & Sons, Ltd.

Maturation- and sex-sensitive depression of hippocampal excitatory transmission in a rat schizophrenia model.

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Patrich, Eti; Piontkewitz, Yael; Peretz, Asher; Weiner, Ina; Attali, Bernard

2016-01-01

Schizophrenia is associated with behavioral and brain structural abnormalities, of which the hippocampus appears to be one of the most consistent region affected. Previous studies performed on the poly I:C model of schizophrenia suggest that alterations in hippocampal synaptic transmission and plasticity take place in the offspring. However, these investigations yielded conflicting results and the neurophysiological alterations responsible for these deficits are still unclear. Here we performed for the first time a longitudinal study examining the impact of prenatal poly I:C treatment and of gender on hippocampal excitatory neurotransmission. In addition, we examined the potential preventive/curative effects of risperidone (RIS) treatment during the peri-adolescence period. Excitatory synaptic transmission was determined by stimulating Schaffer collaterals and monitoring fiber volley amplitude and slope of field-EPSP (fEPSP) in CA1 pyramidal neurons in male and female offspring hippocampal slices from postnatal days (PNDs) 18-20, 34, 70 and 90. Depression of hippocampal excitatory transmission appeared at juvenile age in male offspring of the poly I:C group, while it expressed with a delay in female, manifesting at adulthood. In addition, a reduced hippocampal size was found in both adult male and female offspring of poly I:C treated dams. Treatment with RIS at the peri-adolescence period fully restored in males but partly repaired in females these deficiencies. A maturation- and sex-dependent decrease in hippocampal excitatory transmission occurs in the offspring of poly I:C treated pregnant mothers. Pharmacological intervention with RIS during peri-adolescence can cure in a gender-sensitive fashion early occurring hippocampal synaptic deficits. Copyright © 2015 Elsevier Inc. All rights reserved.

Unsupervised discrimination of patterns in spiking neural networks with excitatory and inhibitory synaptic plasticity.

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Srinivasa, Narayan; Cho, Youngkwan

2014-01-01

A spiking neural network model is described for learning to discriminate among spatial patterns in an unsupervised manner. The network anatomy consists of source neurons that are activated by external inputs, a reservoir that resembles a generic cortical layer with an excitatory-inhibitory (EI) network and a sink layer of neurons for readout. Synaptic plasticity in the form of STDP is imposed on all the excitatory and inhibitory synapses at all times. While long-term excitatory STDP enables sparse and efficient learning of the salient features in inputs, inhibitory STDP enables this learning to be stable by establishing a balance between excitatory and inhibitory currents at each neuron in the network. The synaptic weights between source and reservoir neurons form a basis set for the input patterns. The neural trajectories generated in the reservoir due to input stimulation and lateral connections between reservoir neurons can be readout by the sink layer neurons. This activity is used for adaptation of synapses between reservoir and sink layer neurons. A new measure called the discriminability index (DI) is introduced to compute if the network can discriminate between old patterns already presented in an initial training session. The DI is also used to compute if the network adapts to new patterns without losing its ability to discriminate among old patterns. The final outcome is that the network is able to correctly discriminate between all patterns-both old and new. This result holds as long as inhibitory synapses employ STDP to continuously enable current balance in the network. The results suggest a possible direction for future investigation into how spiking neural networks could address the stability-plasticity question despite having continuous synaptic plasticity.

Addiction to opioids in chronic pain patients: a literature review

DEFF Research Database (Denmark)

Højsted, Jette; Sjøgren, Per

2007-01-01

, incidence and prevalence of addiction in opioid treated pain patients, screening tools for assessing opioid addiction in chronic pain patients and recommendations regarding addiction problems in national and international guidelines for opioid treatment in cancer patients and chronic non-malignant pain...... patients. The review indicates that the prevalence of addiction varied from 0% up to 50% in chronic non-malignant pain patients, and from 0% to 7.7% in cancer patients depending of the subpopulation studied and the criteria used. The risk of addiction has to be considered when initiating long-term opioid...... long-term opioid treatment, and specialised treatment facilities for pain management or addiction medicine should be consulted in these cases....

Parenteral opioids for maternal pain management in labour.

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Smith, Lesley A; Burns, Ethel; Cuthbert, Anna

2018-06-05

Parenteral opioids (intramuscular and intravenous drugs including patient-controlled analgesia) are used for pain relief in labour in many countries throughout the world. This review is an update of a review first published in 2010. To assess the effectiveness, safety and acceptability to women of different types, doses and modes of administration of parenteral opioid analgesia in labour. A second objective is to assess the effects of opioids in labour on the baby in terms of safety, condition at birth and early feeding. We searched Cochrane Pregnancy and Childbirth's Trials Register, ClinicalTrials.gov, the WHO International Clinical Trials Registry Platform (ICTRP) (11 May 2017) and reference lists of retrieved studies. We included randomised controlled trials examining the use of intramuscular or intravenous opioids (including patient-controlled analgesia) for women in labour. Cluster-randomised trials were also eligible for inclusion, although none were identified. We did not include quasi-randomised trials. We looked at studies comparing an opioid with another opioid, placebo, no treatment, other non-pharmacological interventions (transcutaneous electrical nerve stimulation (TENS)) or inhaled analgesia. Two review authors independently assessed trials for inclusion and risk of bias, extracted data and checked them for accuracy. We assessed the quality of each evidence synthesis using the GRADE approach. We included 70 studies that compared an opioid with placebo or no treatment, another opioid administered intramuscularly or intravenously or compared with TENS applied to the back. Sixty-one studies involving more than 8000 women contributed data to the review and these studies reported on 34 different comparisons; for many comparisons and outcomes only one study contributed data. All of the studies were conducted in hospital settings, on healthy women with uncomplicated pregnancies at 37 to 42 weeks' gestation. We excluded studies focusing on women with pre

Multiple Sources of Prescription Payment and Risky Opioid Therapy Among Veterans.

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Becker, William C; Fenton, Brenda T; Brandt, Cynthia A; Doyle, Erin L; Francis, Joseph; Goulet, Joseph L; Moore, Brent A; Torrise, Virginia; Kerns, Robert D; Kreiner, Peter W

2017-07-01

Opioid overdose and other related harms are a major source of morbidity and mortality among US Veterans, in part due to high-risk opioid prescribing. We sought to determine whether having multiple sources of payment for opioids-as a marker for out-of-system access-is associated with risky opioid therapy among veterans. Cross-sectional study examining the association between multiple sources of payment and risky opioid therapy among all individuals with Veterans Health Administration (VHA) payment for opioid analgesic prescriptions in Kentucky during fiscal year 2014-2015. Source of payment categories: (1) VHA only source of payment (sole source); (2) sources of payment were VHA and at least 1 cash payment [VHA+cash payment(s)] whether or not there was a third source of payment; and (3) at least one other noncash source: Medicare, Medicaid, or private insurance [VHA+noncash source(s)]. Our outcomes were 2 risky opioid therapies: combination opioid/benzodiazepine therapy and high-dose opioid therapy, defined as morphine equivalent daily dose ≥90 mg. Of the 14,795 individuals in the analytic sample, there were 81.9% in the sole source category, 6.6% in the VHA+cash payment(s) category, and 11.5% in the VHA+noncash source(s) category. In logistic regression, controlling for age and sex, persons with multiple payment sources had significantly higher odds of each risky opioid therapy, with those in the VHA+cash having significantly higher odds than those in the VHA+noncash source(s) group. Prescribers should examine the prescription monitoring program as multiple payment sources increase the odds of risky opioid therapy.

Electroacupuncture-Induced Dynamic Processes of Gene Expression Levels of Endogenous Opioid Peptide Precursors and Opioid Receptors in the CNS of Goats

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Li-Li Cheng

2013-01-01

Full Text Available In order to investigate the dynamic processes of mRNA levels of proenkephalin, proopiomelanocortin, prodynorphin, and opioid receptors (δ-, μ-, and κ-receptor induced by electroacupuncture (EA in the central nerve system, goats were stimulated by EA of 60 Hz for 0.5 h at a set of Baihui, Santai, Ergen, and Sanyangluo points. The pain threshold was measured using the method of potassium iontophoresis. The mRNA levels of the three opioid peptide precursors and three opioid receptors were determined with quantitative real-time PCR and the levels of Met-enkephalin with SABC immunohistochemistry at 0.5 h before and at 0, 2, 4, 6, 8, 12, and 24 h after EA. The results showed that the pain threshold correlated (P<0.01 with Met-enkephalin immunoactivities in the measured nuclei and areas of goats. The analgesic aftereffect lasted for 12 h at least. The mRNA levels of the three opioid peptide precursors and three opioid receptors began to increase at 0 h, reached the peak during the time from 4 h to 6 h or at 12 h, and remained higher at 24 h after EA was discontinued. These results suggested that the initiation of gene expression of opioid peptides and the three receptors may be associated with EA-induced analgesic aftereffect.

Pavlovian conditioning of multiple opioid-like responses in mice.

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Bryant, Camron D; Roberts, Kristofer W; Culbertson, Christopher S; Le, Alan; Evans, Christopher J; Fanselow, Michael S

2009-07-01

Conditional responses in rodents such as locomotion have been reported for drugs of abuse and similar to the placebo response in humans, may be associated with the expectation of reward. We examined several conditional opioid-like responses and the influence of drug expectation on conditioned place preference and concomitant conditional locomotion. Male C57BL/6J mice were conditioned with the selective mu opioid receptor agonist fentanyl (0.2mg/kg, i.p.) in a novel context and subsequently given a vehicle injection. In separate experiments, locomotor activity, Straub tail, hot plate sensitivity, and conditioned place preference (CPP) were measured. Mice exhibited multiple conditional opioid-like responses including conditional hyperlocomotion, a conditional pattern of opioid-like locomotion, Straub tail, analgesia, and place preference. Modulating drug expectation via administration of fentanyl to "demonstrator" mice in the home cage did not affect the expression of conditioned place preference or the concomitant locomotor activity in "observer" mice. In summary, Pavlovian conditioning of an opioid in a novel context induced multiple conditional opioid-like behaviors and provides a model for studying the neurobiological mechanisms of the placebo response in mice.

Acute inflammation induces segmental, bilateral, supraspinally mediated opioid release in the rat spinal cord, as measured by μ-opioid receptor internalization

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Chen, Wenling; Marvizón, Juan Carlos G.

2009-01-01

The objective of this study was to measure opioid release in the spinal cord during acute and long-term inflammation using μ-opioid receptor (MOR) internalization. In particular, we determined whether opioid release occurs in the segments receiving the noxious signals or in the entire spinal cord, and whether it involves supraspinal signals. Internalization of neurokinin 1 receptors (NK1Rs) was measured to track the intensity of the noxious stimulus. Rats received peptidase inhibitors intrathecally to protect opioids from degradation. Acute inflammation of the hindpaw with formalin induced moderate MOR internalization in the L5 segment bilaterally, whereas NK1R internalization occurred only ipsilaterally. MOR internalization was restricted to the lumbar spinal cord, regardless of whether the peptidase inhibitors were injected in a lumbar or thoracic site. Formalin-induced MOR internalization was substantially reduced by isoflurane anesthesia. It was also markedly reduced by a lidocaine block of the cervical-thoracic spinal cord (which did not affect the evoked NK1R internalization) indicating that spinal opioid release is mediated supraspinally. In the absence of peptidase inhibitors, formalin and hindpaw clamp induced a small amount of MOR internalization, which was significantly higher than in controls. To study spinal opioid release during chronic inflammation, we injected Complete Freund's Adjuvant (CFA) in the hindpaw and peptidase inhibitors intrathecally. Two days later, no MOR or NK1R internalization was detected. Furthermore, CFA inflammation decreased MOR internalization induced by clamping the inflamed hindpaw. These results show that acute inflammation, but not chronic inflammation, induce segmental opioid release in the spinal cord that involves supraspinal signals. PMID:19298846

Acute inflammation induces segmental, bilateral, supraspinally mediated opioid release in the rat spinal cord, as measured by mu-opioid receptor internalization.

Science.gov (United States)

Chen, W; Marvizón, J C G

2009-06-16

The objective of this study was to measure opioid release in the spinal cord during acute and long-term inflammation using mu-opioid receptor (MOR) internalization. In particular, we determined whether opioid release occurs in the segments receiving the noxious signals or in the entire spinal cord, and whether it involves supraspinal signals. Internalization of neurokinin 1 receptors (NK1Rs) was measured to track the intensity of the noxious stimulus. Rats received peptidase inhibitors intrathecally to protect opioids from degradation. Acute inflammation of the hind paw with formalin induced moderate MOR internalization in the L5 segment bilaterally, whereas NK1R internalization occurred only ipsilaterally. MOR internalization was restricted to the lumbar spinal cord, regardless of whether the peptidase inhibitors were injected in a lumbar or thoracic site. Formalin-induced MOR internalization was substantially reduced by isoflurane anesthesia. It was also markedly reduced by a lidocaine block of the cervical-thoracic spinal cord (which did not affect the evoked NK1R internalization) indicating that spinal opioid release is mediated supraspinally. In the absence of peptidase inhibitors, formalin and hind paw clamp induced a small amount of MOR internalization, which was significantly higher than in controls. To study spinal opioid release during chronic inflammation, we injected complete Freund's adjuvant (CFA) in the hind paw and peptidase inhibitors intrathecally. Two days later, no MOR or NK1R internalization was detected. Furthermore, CFA inflammation decreased MOR internalization induced by clamping the inflamed hind paw. These results show that acute inflammation, but not chronic inflammation, induces segmental opioid release in the spinal cord that involves supraspinal signals.

Electrical stimulation of dog pudendal nerve regulates the excitatory pudendal-to-bladder reflex

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Yan-he Ju

2016-01-01

Full Text Available Pudendal nerve plays an important role in urine storage and voiding. Our hypothesis is that a neuroprosthetic device placed in the pudendal nerve trunk can modulate bladder function after suprasacral spinal cord injury. We had confirmed the inhibitory pudendal-to-bladder reflex by stimulating either the branch or the trunk of the pudendal nerve. This study explored the excitatory pudendal-to-bladder reflex in beagle dogs, with intact or injured spinal cord, by electrical stimulation of the pudendal nerve trunk. The optimal stimulation frequency was approximately 15-25 Hz. This excitatory effect was dependent to some extent on the bladder volume. We conclude that stimulation of the pudendal nerve trunk is a promising method to modulate bladder function.

Effects of opioid drugs on dopamine mediated locomotor activity in rats

Energy Technology Data Exchange (ETDEWEB)

Leathern, L L

1986-01-01

Opioid drugs influence various behavioural parameters including locomotor activity in experimental animals. The interaction between the opioid and dopaminergic systems is one possible explanation for the effect of opioid drugs on locomotor activity. In this study behavioural and biochemical assays were done to investigate the interaction between the opioid and dopaminergic systems. Behavioural studies were done by measurement of locomotor activity (LA) of rats after acute or chronic pretreatment with opioid andor dopaminergic drugs. Biochemical studies were in the form of radioligand binding assays, the effect on the number (Bmax) and affinity (K/sub D/) of receptors was measured after chronic pretreatment with opioid andor dopaminergic drugs. The opioid drugs used are morphine, nalbuphine and naloxone. Dopaminergic drugs used included: agonists-apomorphine and piribedil; antagonists-pimozide, haloperidol, chlorpromazine. In the acute situation increased LA was obtained with morphine and the DA agonists. A correlation between the behavioural and biochemical assays was found. Chronic pretreatment with morphine enhanced apomorphine induced LA, this supersensitivity was also measured as an increased receptor density (Bmax) of D2 receptors in the striatum. Chronic morphine pretreatment caused a decrease in morphine induced LA, while this subsensitivity was not apparent in the ligand binding assays - where no change in receptor number was observed. Chronic naloxone pretreatment enhanced morphine induced LA, as well as increased the Bmax of opioid receptors in the whole brain. It is concluded that an interaction between the opioid and dopaminergic systems does exist, and may account for the mechanism of action of the opioids.

TGF-β Signaling in Dopaminergic Neurons Regulates Dendritic Growth, Excitatory-Inhibitory Synaptic Balance, and Reversal Learning

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Sarah X. Luo

2016-12-01

Full Text Available Neural circuits involving midbrain dopaminergic (DA neurons regulate reward and goal-directed behaviors. Although local GABAergic input is known to modulate DA circuits, the mechanism that controls excitatory/inhibitory synaptic balance in DA neurons remains unclear. Here, we show that DA neurons use autocrine transforming growth factor β (TGF-β signaling to promote the growth of axons and dendrites. Surprisingly, removing TGF-β type II receptor in DA neurons also disrupts the balance in TGF-β1 expression in DA neurons and neighboring GABAergic neurons, which increases inhibitory input, reduces excitatory synaptic input, and alters phasic firing patterns in DA neurons. Mice lacking TGF-β signaling in DA neurons are hyperactive and exhibit inflexibility in relinquishing learned behaviors and re-establishing new stimulus-reward associations. These results support a role for TGF-β in regulating the delicate balance of excitatory/inhibitory synaptic input in local microcircuits involving DA and GABAergic neurons and its potential contributions to neuropsychiatric disorders.

Disruption of gut homeostasis by opioids accelerates HIV disease progression

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Jingjing eMeng

2015-06-01

Full Text Available Cumulative studies during the past 30 years have established the correlation between opioid abuse and human immunodeficiency virus (HIV infection. Further studies also demonstrate that opioid addiction is associated with faster progression to AIDS in patients. Recently, it was revealed that disruption of gut homeostasis and subsequent microbial translocation play important roles in pathological activation of the immune system during HIV infection and contributes to accelerated disease progression. Similarly, opioids have been shown to modulate gut immunity and induce gut bacterial translocation. This review will explore the mechanisms by which opioids accelerate HIV disease progression by disrupting gut homeostasis. Better understanding of these mechanisms will facilitate the search for new therapeutic interventions to treat HIV infection especially in opioid abusing population.

Opioid Overdoses Treated in Emergency Departments PSA (:60)

Centers for Disease Control (CDC) Podcasts

This 60 second public service announcement is based on the March 2018 CDC Vital Signs report. Opioid overdoses continue to increase in the United States. Learn what can be done to help prevent opioid overdose and death.

Traveling wave front solutions in lateral-excitatory neuronal networks

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Sittipong Ruktamatakul

2008-05-01

Full Text Available In this paper, we discuss the shape of traveling wave front solutions to a neuronal model with the connection function to be of lateral excitation type. This means that close connecting cells have an inhibitory influence, while cells that aremore distant have an excitatory influence. We give results on the shape of the wave fronts solutions, which exhibit different shapes depend ing on the size of a threshold parameter.

GABAergic activities control spike timing- and frequency-dependent long-term depression at hippocampal excitatory synapses

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Makoto Nishiyama

2010-06-01

Full Text Available GABAergic interneuronal network activities in the hippocampus control a variety of neural functions, including learning and memory, by regulating θ and γ oscillations. How these GABAergic activities at pre- and post-synaptic sites of hippocampal CA1 pyramidal cells differentially contribute to synaptic function and plasticity during their repetitive pre- and post-synaptic spiking at θ and γ oscillations is largely unknown. We show here that activities mediated by postsynaptic GABAARs and presynaptic GABABRs determine, respectively, the spike timing- and frequency-dependence of activity-induced synaptic modifications at Schaffer collateral-CA1 excitatory synapses. We demonstrate that both feedforward and feedback GABAAR-mediated inhibition in the postsynaptic cell controls the spike timing-dependent long-term depression of excitatory inputs (“e-LTD” at the θ frequency. We also show that feedback postsynaptic inhibition specifically causes e-LTD of inputs that induce small postsynaptic currents (<70 pA with LTP timing, thus enforcing the requirement of cooperativity for induction of long-term potentiation at excitatory inputs (“e-LTP”. Furthermore, under spike-timing protocols that induce e-LTP and e-LTD at excitatory synapses, we observed parallel induction of LTP and LTD at inhibitory inputs (“i-LTP” and “i-LTD” to the same postsynaptic cells. Finally, we show that presynaptic GABABR-mediated inhibition plays a major role in the induction of frequency-dependent e-LTD at α and β frequencies. These observations demonstrate the critical influence of GABAergic interneuronal network activities in regulating the spike timing and frequency dependences of long-term synaptic modifications in the hippocampus.

Non-analgesic effects of opioids

DEFF Research Database (Denmark)

Højsted, Jette; Kurita, Geana Paula; Kendall, Sally

2012-01-01

Opioids constitute the basis for pharmacological treatment of moderate to severe pain in cancer pain and non-cancer pain patients. Their action is mediated by the activation of opioid receptors, which integrates the pain modulation system with other effects in the central nervous system including...... groups: no effects or worsening of cognitive function in cancer pain patients and no effect or improvements in the chronic non-cancer pain patients, however, due to methodological limitations and a huge variety of designs definite conclusions are difficult to draw from the studies. In studies of higher...

Nicotine and endogenous opioids: neurochemical and pharmacological evidence.

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Hadjiconstantinou, Maria; Neff, Norton H

2011-06-01

Although the mesolimbic dopamine hypothesis is the most influential theory of nicotine reward and reinforcement, there has been a consensus that other neurotransmitter systems contribute to the addictive properties of nicotine as well. In this regard, the brain opioidergic system is of interest. Striatum is rich in opioid peptides and opioid receptors, and striatal opioidergic neurons are engaged in a bidirectional communication with midbrain dopaminergic neurons, closely regulating each other's activity. Enkephalins and dynorphins exert opposing actions on dopaminergic neurons, increasing and decreasing dopamine release respectively, and are components of circuits promoting positive or negative motivational and affective states. Moreover, dopamine controls the synthesis of striatal enkephalins and dynorphins. Evidence suggests that opioidergic function is altered after nicotine and endogenous opioids are involved in nicotine's behavioral effects. 1) The synthesis and release of β-endorphin, met-enkephalin and dynorphin in brain, especially nucleus accumbens (NAc), are altered after acute or chronic nicotine treatment and during nicotine withdrawal. 2) Although opioid receptor binding and mRNA do not appear to change in the striatum during nicotine withdrawal, the activity of κ-opioid (KOPr) and δ-opioid (DOPr) receptors is attenuated in NAc. 3) The nicotine withdrawal syndrome reminisces that of opiates, and naloxone precipitates some of its somatic, motivational, and affective signs. 4) Genetic and pharmacological studies indicate that μ-opioid (MOPr) receptors are mainly involved in nicotine reward, while DOPrs contribute to the emotional and KOPrs to the aversive responses of nicotine. 5) Finally, MOPrs and enkephalin, but not β-endorphin or dynorphin, are necessary for the physical manifestations of nicotine withdrawal. This article is part of a Special Issue entitled 'Trends in neuropharmacology: in memory of Erminio Costa'. Copyright © 2010 Elsevier

Buprenorphine implants in medical treatment of opioid addiction.

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Chavoustie, Steven; Frost, Michael; Snyder, Ole; Owen, Joel; Darwish, Mona; Dammerman, Ryan; Sanjurjo, Victoria

2017-08-01

Opioid use disorder is a chronic, relapsing disease that encompasses use of both prescription opioids and heroin and is associated with a high annual rate of overdose deaths. Medical treatment has proven more successful than placebo treatment or psychosocial intervention, and the partial µ-opioid receptor agonist and κ-opioid receptor antagonist buprenorphine is similar in efficacy to methadone while offering lower risk of respiratory depression. However, frequent dosing requirements and potential for misuse and drug diversion contribute to significant complications with treatment adherence for available formulations. Areas covered: This review describes the development of and preliminary data from clinical trials of an implantable buprenorphine formulation. Efficacy and safety data from comparative studies with other administrations of buprenorphine, including tablets and sublingual film, will be described. Key premises of the Risk Evaluation and Mitigation Strategy program for safely administering buprenorphine implants, which all prescribing physicians must complete, are also discussed. Expert commentary: Long-acting implantable drug formulations that offer consistent drug delivery and lower risk of misuse, diversion, or accidental pediatric exposure over traditional formulations represent a promising development for the effective treatment of opioid use disorder.

Pain Therapy Guided by Purpose and Perspective in Light of the Opioid Epidemic

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Amie L. Severino

2018-04-01

Full Text Available Prescription opioid misuse is an ongoing and escalating epidemic. Although these pharmacological agents are highly effective analgesics prescribed for different types of pain, opioids also induce euphoria, leading to increasing diversion and misuse. Opioid use and related mortalities have developed in spite of initial claims that OxyContin, one of the first opioids prescribed in the USA, was not addictive in the presence of pain. These claims allayed the fears of clinicians and contributed to an increase in the number of prescriptions, quantity of drugs manufactured, and the unforeseen diversion of these drugs for non-medical uses. Understanding the history of opioid drug development, the widespread marketing campaign for opioids, the immense financial incentive behind the treatment of pain, and vulnerable socioeconomic and physical demographics for opioid misuse give perspective on the current epidemic as an American-born problem that has expanded to global significance. In light of the current worldwide opioid epidemic, it is imperative that novel opioids are developed to treat pain without inducing the euphoria that fosters physical dependence and addiction. We describe insights from preclinical findings on the properties of opioid drugs that offer insights into improving abuse-deterrent formulations. One finding is that the ability of some agonists to activate one pathway over another, or agonist bias, can predict whether several novel opioid compounds bear promise in treating pain without causing reward among other off-target effects. In addition, we outline how the pharmacokinetic profile of each opioid contributes to their potential for misuse and discuss the emergence of mixed agonists as a promising pipeline of opioid-based analgesics. These insights from preclinical findings can be used to more effectively identify opioids that treat pain without causing physical dependence and subsequent opioid abuse.

Pain Therapy Guided by Purpose and Perspective in Light of the Opioid Epidemic

Science.gov (United States)

Severino, Amie L.; Shadfar, Arash; Hakimian, Joshua K.; Crane, Oliver; Singh, Ganeev; Heinzerling, Keith; Walwyn, Wendy M.

2018-01-01

Prescription opioid misuse is an ongoing and escalating epidemic. Although these pharmacological agents are highly effective analgesics prescribed for different types of pain, opioids also induce euphoria, leading to increasing diversion and misuse. Opioid use and related mortalities have developed in spite of initial claims that OxyContin, one of the first opioids prescribed in the USA, was not addictive in the presence of pain. These claims allayed the fears of clinicians and contributed to an increase in the number of prescriptions, quantity of drugs manufactured, and the unforeseen diversion of these drugs for non-medical uses. Understanding the history of opioid drug development, the widespread marketing campaign for opioids, the immense financial incentive behind the treatment of pain, and vulnerable socioeconomic and physical demographics for opioid misuse give perspective on the current epidemic as an American-born problem that has expanded to global significance. In light of the current worldwide opioid epidemic, it is imperative that novel opioids are developed to treat pain without inducing the euphoria that fosters physical dependence and addiction. We describe insights from preclinical findings on the properties of opioid drugs that offer insights into improving abuse-deterrent formulations. One finding is that the ability of some agonists to activate one pathway over another, or agonist bias, can predict whether several novel opioid compounds bear promise in treating pain without causing reward among other off-target effects. In addition, we outline how the pharmacokinetic profile of each opioid contributes to their potential for misuse and discuss the emergence of mixed agonists as a promising pipeline of opioid-based analgesics. These insights from preclinical findings can be used to more effectively identify opioids that treat pain without causing physical dependence and subsequent opioid abuse. PMID:29740351

GRK2 Constitutively Governs Peripheral Delta Opioid Receptor Activity

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Allison Doyle Brackley

2016-09-01

Full Text Available Opioids remain the standard for analgesic care; however, adverse effects of systemic treatments contraindicate long-term administration. While most clinical opioids target mu opioid receptors (MOR, those that target the delta class (DOR also demonstrate analgesic efficacy. Furthermore, peripherally restrictive opioids represent an attractive direction for analgesia. However, opioid receptors including DOR are analgesically incompetent in the absence of inflammation. Here, we report that G protein-coupled receptor kinase 2 (GRK2 naively associates with plasma membrane DOR in peripheral sensory neurons to inhibit analgesic agonist efficacy. This interaction prevents optimal Gβ subunit association with the receptor, thereby reducing DOR activity. Importantly, bradykinin stimulates GRK2 movement away from DOR and onto Raf kinase inhibitory protein (RKIP. protein kinase C (PKC-dependent RKIP phosphorylation induces GRK2 sequestration, restoring DOR functionality in sensory neurons. Together, these results expand the known function of GRK2, identifying a non-internalizing role to maintain peripheral DOR in an analgesically incompetent state.

Psychiatric disorders in opioid dependants.

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Ahmadi, Jamshid; Toobaee, Shahin; Kharras, Mohammad; Radmehr, Mohammad

2003-09-01

Psychiatric disorders are common among substance dependants. The objectives of this study were to assess the rate of neurotic disorders among opioid addicts, and reassess the rate of those neurotic disorders two weeks after complete detoxification of the patients. Data were gathered from 500 (496 men and 4 women) opioid dependants, using DSM-IV criteria. The Middlesex Hospital Questionnaire (MHQ) was used to measure free-floating anxiety, depression, phobia, obsession, hysteria and somatization. Four hundred and ninety-six (99.2%) of the subjects were men of whom the majority (65.2%) were married, 26.4% single and the others were divorced or separated. Three hundred and thirty-four (66.8%) were in age range of 20 to 39 years. Of the subjects 154 (30.8) were self-employed, 116 (23.2%) were factory workers, 100 (20%) unemployed, 64 (12.8%) employees and 32 (6.4%) retailers. The majority, 322 (64.4%), reported elementary and high school as their level of education and only 20 (4%) were illiterate. The means for neurotic disorders (using the MHQ) before and two weeks after detoxification were 10.12 and 9.98 for anxiety, 7.54 and 7.41 for phobia, 10.10 and 9.76 for depression, 11.11 and 11.05 for obsession, 8.47 and 8.49 for hysteria and 9.82 and 9.46 for somatization, respectively. The mean difference was significant only for depression. Present findings indicated that the rate of neurotic disorders in opioid dependants is high and (except for depression) was not significantly different before detoxification and two weeks after detoxification. Opium was found to be the most prevalent form of opioid used. Also it can be concluded that during the last years some demographic characteristics of Iranian opioid addicts in this sample have changed. Cultural attitudes toward substance use quite likely affect the pattern of substance use. These findings can be considered when planning preventive and therapeutic programs.

Glucose rapidly induces different forms of excitatory synaptic plasticity in hypothalamic POMC neurons.

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Jun Hu

Full Text Available Hypothalamic POMC neurons are required for glucose and energy homeostasis. POMC neurons have a wide synaptic connection with neurons both within and outside the hypothalamus, and their activity is controlled by a balance between excitatory and inhibitory synaptic inputs. Brain glucose-sensing plays an essential role in the maintenance of normal body weight and metabolism; however, the effect of glucose on synaptic transmission in POMC neurons is largely unknown. Here we identified three types of POMC neurons (EPSC(+, EPSC(-, and EPSC(+/- based on their glucose-regulated spontaneous excitatory postsynaptic currents (sEPSCs, using whole-cell patch-clamp recordings. Lowering extracellular glucose decreased the frequency of sEPSCs in EPSC(+ neurons, but increased it in EPSC(- neurons. Unlike EPSC(+ and EPSC(- neurons, EPSC(+/- neurons displayed a bi-phasic sEPSC response to glucoprivation. In the first phase of glucoprivation, both the frequency and the amplitude of sEPSCs decreased, whereas in the second phase, they increased progressively to the levels above the baseline values. Accordingly, lowering glucose exerted a bi-phasic effect on spontaneous action potentials in EPSC(+/- neurons. Glucoprivation decreased firing rates in the first phase, but increased them in the second phase. These data indicate that glucose induces distinct excitatory synaptic plasticity in different subpopulations of POMC neurons. This synaptic remodeling is likely to regulate the sensitivity of the melanocortin system to neuronal and hormonal signals.

Glucose rapidly induces different forms of excitatory synaptic plasticity in hypothalamic POMC neurons.

Science.gov (United States)

Hu, Jun; Jiang, Lin; Low, Malcolm J; Rui, Liangyou

2014-01-01

Hypothalamic POMC neurons are required for glucose and energy homeostasis. POMC neurons have a wide synaptic connection with neurons both within and outside the hypothalamus, and their activity is controlled by a balance between excitatory and inhibitory synaptic inputs. Brain glucose-sensing plays an essential role in the maintenance of normal body weight and metabolism; however, the effect of glucose on synaptic transmission in POMC neurons is largely unknown. Here we identified three types of POMC neurons (EPSC(+), EPSC(-), and EPSC(+/-)) based on their glucose-regulated spontaneous excitatory postsynaptic currents (sEPSCs), using whole-cell patch-clamp recordings. Lowering extracellular glucose decreased the frequency of sEPSCs in EPSC(+) neurons, but increased it in EPSC(-) neurons. Unlike EPSC(+) and EPSC(-) neurons, EPSC(+/-) neurons displayed a bi-phasic sEPSC response to glucoprivation. In the first phase of glucoprivation, both the frequency and the amplitude of sEPSCs decreased, whereas in the second phase, they increased progressively to the levels above the baseline values. Accordingly, lowering glucose exerted a bi-phasic effect on spontaneous action potentials in EPSC(+/-) neurons. Glucoprivation decreased firing rates in the first phase, but increased them in the second phase. These data indicate that glucose induces distinct excitatory synaptic plasticity in different subpopulations of POMC neurons. This synaptic remodeling is likely to regulate the sensitivity of the melanocortin system to neuronal and hormonal signals.

Novel pharmacotherapeutic strategies for treatment of opioid-induced neonatal abstinence syndrome

OpenAIRE

McLemore, Gabrielle L.; Lewis, Tamorah; Jones, Catherine H.; Gauda, Estelle B.

2012-01-01

The non-medical use of prescription drugs, in general, and opioids, in particular, is a national epidemic, resulting in enormous addiction rates, healthcare expenditures, and overdose deaths. Prescription opioids are overly prescribed, illegally trafficked, and frequently abused, all of which have created a new opioid addiction pathway, adding to the number of opioid-dependent newborns requiring treatment for neonatal abstinence syndrome (NAS), and contributing to challenges in effective care...

Most drug overdose deaths from nonprescription opioids

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Robbins RA

2016-12-01

Full Text Available No abstract available. Article truncated at 150 words. The Centers for Disease Control (CDC is reporting in Morbidity and Mortality Weekly that the number of people dying from an opioid overdose rose 15.5% from 2014 to 2015, but the increase had little to do with prescription painkillers such as oxycodone or hydrocodone (1. Roughly 52,000 people died from drug overdoses in 2015 and of those deaths 33,091 involved an opioid. The increases in “death rates were driven by synthetic opioids other than methadone (72.2%, most likely illicitly-manufactured fentanyl, and heroin (20.6%”. Deaths from methadone, which is usually prescribed by physicians, decreased 9.1%. The largest increase in deaths occurred in the South and Northeast with 3% and 24% increases in deaths from synthetic opioids from 2014 to 2015. In the Midwest and West, there were more modest 17% and 9% increases during the same period. States in the Southwest with “good” to “excellent” reporting included Colorado, Nevada, and New …

A nationwide pharmacy chain responds to the opioid epidemic.

Science.gov (United States)

Shafer, Emily; Bergeron, Nyahne; Smith-Ray, Renae; Robson, Chester; O'Koren, Rachel

To describe the 3-pronged approach taken by a large national retail pharmacy chain to address the opioid epidemic and associated overdoses. Large national retail pharmacy chain with more than 8200 stores in 50 states. Eight million customer interactions daily through in-store and digital settings. This is a company with a long history of responding to public health crises. Initiated 3 programs to respond to the opioid crisis: 1) provide safe medication disposal kiosks; 2) expand national access to naloxone; and 3) provide education on the risk and avoidance of opioid overdose. Used the RE-AIM framework to evaluate and enhance the quality, speed, and public health impact of the interventions. Not applicable. Early results are safe medication disposal kiosks in more than 43 states, naloxone-dispensing program in 33 states, and patient and support system education using the Opioid Overdose Toolkit from the Substance Abuse and Mental Health Services Administration. The availability of safe drug-disposal kiosks, naloxone dispensing at pharmacies, and patient education are key prevention initiatives to address the opioid epidemic and reduce the increasing national burden of opioid overdose. Early results are quantitatively and qualitatively promising. Copyright © 2017 American Pharmacists Association®. Published by Elsevier Inc. All rights reserved.

Molecular and cellular mechanisms of the age-dependency of opioid analgesia and tolerance

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Zhao Jing

2012-05-01

Full Text Available Abstract The age-dependency of opioid analgesia and tolerance has been noticed in both clinical observation and laboratory studies. Evidence shows that many molecular and cellular events that play essential roles in opioid analgesia and tolerance are actually age-dependent. For example, the expression and functions of endogenous opioid peptides, multiple types of opioid receptors, G protein subunits that couple to opioid receptors, and regulators of G protein signaling (RGS proteins change with development and age. Other signaling systems that are critical to opioid tolerance development, such as N-methyl-D-aspartic acid (NMDA receptors, also undergo age-related changes. It is plausible that the age-dependent expression and functions of molecules within and related to the opioid signaling pathways, as well as age-dependent cellular activity such as agonist-induced opioid receptor internalization and desensitization, eventually lead to significant age-dependent changes in opioid analgesia and tolerance development.

Clinical utility of naloxegol in the treatment of opioid-induced constipation

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Bruner HC

2015-06-01

Full Text Available Heather C Bruner,1 Rabia S Atayee,2 Kyle P Edmonds,3 Gary T Buckholz3 1Scripps Health and University of California San Diego, Joint Hospice and Palliative Medicine Fellowship, San Diego, CA, USA; 2University of California San Diego, Skaggs School of Pharmacy and Pharmaceutical Sciences, La Jolla, CA, USA; 3Department of Medicine, University of California San Diego, Doris A Howell Palliative Care Service, La Jolla, CA, USA Abstract: Opioids are a class of medications frequently used for the treatment of acute and chronic pain, exerting their desired effects at central opioid receptors. Agonism at peripherally located opioid receptors, however, leads to opioid-induced constipation (OIC, one of the most frequent and debilitating side effects of prolonged opioid use. Insufficient relief of OIC with lifestyle modification and traditional laxative treatments may lead to decreased compliance with opioid regimens and undertreated pain. Peripherally acting mu-opioid receptor antagonists (PAMORAs offer the reversal of OIC without loss of central pain relief. Until recently, PAMORAs were restricted to subcutaneous route or to narrow patient populations. Naloxegol is the first orally dosed PAMORA indicated for the treatment of OIC in noncancer patients. Studies have suggested its efficacy in patients failing traditional constipation treatments; however, insufficient evidence exists to establish its role in primary prevention of OIC at this time. Keywords: opioid-induced bowel dysfunction, chronic pain, peripherally-acting mu-opioid antagonist, bowel care, OIC, OIBD 

Binding-site analysis of opioid receptors using monoclonal anti-idiotypic antibodies

International Nuclear Information System (INIS)

Conroy, W.G.

1988-01-01

Structural relatedness between the variable region of anti-ligand antibodies and opioid binding sites allowed the generation of anti-idiotypic antibodies which recognized opioid receptors. The IgG 3 k antibodies which bound to opioid receptors were obtained when an anti-morphine antiserum was the idiotype. Both antibodies bound to opioid receptors, but only one of these blocked the binding of [ 3 H]naloxone. The antibody which did not inhibit the binding of [ 3 H]naloxone was itself displaced from the receptor by opioid ligands. The unique binding properties displayed by this antibody indicated that anti-idiotypic antibodies are not always a perfect image of the original ligand, and therefore may be more useful than typical ligands as probes for the receptor. An auto-anti-idiotypic technique was successfully used to obtain anti-opioid receptor antibodies. Another IgG 3 k antibody that blocked the binding of [ 3 H]naloxone to rat brain opioid receptors was obtained when a mouse was immunized with naloxone conjugated to bovine serum albumin. These data confirmed that an idiotype-anti-idiotype network which can generate an anti-receptor antibody normally functions when an opioid ligand is introduced into an animal in an immunogenic form

Characteristics of prescribers whose patients shop for opioids: results from a cohort study.

Science.gov (United States)

Cepeda, M Soledad; Fife, Daniel; Berlin, Jesse A; Mastrogiovanni, Gregory; Yuan, Yingli

2012-01-01

Little is known about the prevalence of opioid shoppers in clinical practices and the relation between prescriber characteristics and the risk of having opioid shoppers. Describe the prevalence of opioid shoppers in prescribers' practices. Assess the relation between prescribers' characteristics and patient opioid shopping behavior. Retrospective cohort study using a large US retail prescription database. Patients with ≥1 opioid dispensing were followed 18 months. These patients' prescribers are the focus of the study. A patient was a "shopper" if he or she had opioid prescriptions written by ≥1 prescriber with ≥1 day of overlap filled at ≥3 pharmacies and a "heavy shopper" if he or she had ≥5 shopping episodes. The proportions of shoppers by prescriber and the proportion of prescribers with ≥1 shopper or heavy shopper were calculated. Among 858,290 opioid prescribers, most (87 percent) had no shoppers and 98 percent had no heavy shoppers. Prescribers who were aged 70-79 years, male, or who prescribed schedule II opioids had an increased likelihood of having shoppers. As the number of patients for whom a prescriber prescribed opioids increased, the proportion of shoppers also increased. Prescribers with 66 or more patients receiving opioids, who represented 25 percent of prescribers, prescribed for 82 percent of all shoppers. The great majority of opioid prescribers appear to have no shoppers in their practice. Any educational program will be more cost effective if targeted to prescribers of schedule II opioids with a large volume of patients requiring opioids.

The challenge of perioperative pain management in opioid-tolerant patients

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Coluzzi F

2017-09-01

Full Text Available Flaminia Coluzzi,1 Francesca Bifulco,2 Arturo Cuomo,2 Mario Dauri,3 Claudio Leonardi,4 Rita Maria Melotti,5 Silvia Natoli,3 Patrizia Romualdi,6 Gennaro Savoia,7 Antonio Corcione8 1Department of Medical and Surgical Sciences and Biotechnologies, Unit of Anaesthesia, Intensive Care and Pain Medicine, Sapienza University of Rome, Polo Pontino, Latina, 2National Cancer Institute “G Pascale” Foundation, Unit of Anaesthesia, Intensive Care and Pain Medicine, Naples, 3Department of Clinical Science and Translational Medicine, Tor Vergata University of Rome, 4Addiction Disease Department, Local Health Unit (ASL Rome 2, Rome, 5Department of Medical and Surgical Sciences, 6Department of Pharmacy and Biotechnology, Alma Mater Studiorum University of Bologna, Bologna, 7Department Anesthesia, Fatebenefratelli Hospital, Naples, 8Unit of Anaesthesia and Intensive Care, Dei Colli Hospital, V. Monaldi, Naples, Italy Abstract: The increasing number of opioid users among chronic pain patients, and opioid abusers among the general population, makes perioperative pain management challenging for health care professionals. Anesthesiologists, surgeons, and nurses should be familiar with some pharmacological phenomena which are typical of opioid users and abusers, such as tolerance, physical dependence, hyperalgesia, and addiction. Inadequate pain management is very common in these patients, due to common prejudices and fears. The target of preoperative evaluation is to identify comorbidities and risk factors and recognize signs and symptoms of opioid abuse and opioid withdrawal. Clinicians are encouraged to plan perioperative pain medications and to refer these patients to psychiatrists and addiction specialists for their evaluation. The aim of this review was to give practical suggestions for perioperative management of surgical opioid-tolerant patients, together with schemes of opioid conversion for chronic pain patients assuming oral or transdermal opioids, and

Delayed Ego Strength Development in Opioid Dependent Adolescents and Young Adults

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Abramoff, Benjamin A.; Lange, Hannah L. H.; Matson, Steven C.; Cottrill, Casey B.; Bridge, Jeffrey A.; Abdel-Rasoul, Mahmoud; Bonny, Andrea E.

2015-01-01

Objective. To evaluate ego strengths, in the context of Erikson's framework, among adolescents and young adults diagnosed with opioid dependence as compared to non-drug using youth. Methods. Opioid dependent (n = 51) and non-drug using control (n = 31) youth completed the self-administered Psychosocial Inventory of Ego Strengths (PIES). The PIES assesses development in the framework of Erikson's ego strength stages. Multivariate linear regression modeling assessed the independent association of the primary covariate (opioid dependent versus control) as well as potential confounding variables (e.g., psychiatric comorbidities, intelligence) with total PIES score. Results. Mean total PIES score was significantly lower in opioid dependent youth (231.65 ± 30.39 opioid dependent versus 270.67 ± 30.06 control; p development. A treatment approach acknowledging this delay may be needed in the counseling and treatment of adolescents with opioid dependence. PMID:26664819

Adrenergic Agonists Bind to Adrenergic-Receptor-Like Regions of the Mu Opioid Receptor, Enhancing Morphine and Methionine-Enkephalin Binding: A New Approach to "Biased Opioids"?

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Root-Bernstein, Robert; Turke, Miah; Subhramanyam, Udaya K Tiruttani; Churchill, Beth; Labahn, Joerg

2018-01-17

Extensive evidence demonstrates functional interactions between the adrenergic and opioid systems in a diversity of tissues and organs. While some effects are due to receptor and second messenger cross-talk, recent research has revealed an extracellular, allosteric opioid binding site on adrenergic receptors that enhances adrenergic activity and its duration. The present research addresses whether opioid receptors may have an equivalent extracellular, allosteric adrenergic binding site that has similar enhancing effects on opioid binding. Comparison of adrenergic and opioid receptor sequences revealed that these receptors share very significant regions of similarity, particularly in some of the extracellular and transmembrane regions associated with adrenergic binding in the adrenergic receptors. Five of these shared regions from the mu opioid receptor (muOPR) were synthesized as peptides and tested for binding to adrenergic, opioid and control compounds using ultraviolet spectroscopy. Adrenergic compounds bound to several of these muOPR peptides with low micromolar affinity while acetylcholine, histamine and various adrenergic antagonists did not. Similar studies were then conducted with purified, intact muOPR with similar results. Combinations of epinephrine with methionine enkephalin or morphine increased the binding of both by about half a log unit. These results suggest that muOPR may be allosterically enhanced by adrenergic agonists.

Parenteral Opioid Analgesics Utilization Pattern in Amir-al-Momenin Hospital, Zabol-IRAN

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Hossein Vatanpour

2016-08-01

Full Text Available Opioids are the most available medicines to get rid of any general severe pain and avoiding of any deleterious sequential that can worsen patient outcomes. Rational prescription of opioid analgesics with respect to the possibility of abuse is a big concern in the medical care costs. Zabol, where is located in eastern part of Iran and has common border with Afghanistanhas the most opioid traffic in the region. In this study the rational prescription of parenteral opioid in Amir-al-Momenin general hospital was investigated. A retrospective drug utilization review was performed on 509 in-patients who received parenteral opioids including Morphine, Pethidin, Pentazocin, Fentanyl, Alfentanil, Sufentanil and Methadone from March 21sttoSeptember 23rd, 2011. Multivariate conditional regression modeling was used to determine independent predictors for daily parenteral opioid consumption. Total daily parenteral opioid consumption was 38.63 DDDs/100bed-days for Morphine, Pethidine and Pentazocin and 84564.78 PFEQs/100bed-days for Fentanyl, Alfentanil and Sufentanil and 766 mg for Methadone. Pethidine was the most frequently prescribed parenteral opioid. Most patients who were prescribed by the intramuscular routes, ordered PRN. Daily parenteral opioid consumption was the highest in the emergency ward whereas it was considered as the lowest in the intensive care unit[ICU]. According to our findings, total daily parenteral opioid consumption was almost high in Amir-al-Momenin Hospital. Unlike to some relevant factors that can effect on the consumption of analgesic opioids like gender, age, drug-drug interaction and etc, we found no rational prescription and consumption in the mentioned hospital.

TRV0109101, a G Protein-Biased Agonist of the µ-Opioid Receptor, Does Not Promote Opioid-Induced Mechanical Allodynia following Chronic Administration.

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Koblish, Michael; Carr, Richard; Siuda, Edward R; Rominger, David H; Gowen-MacDonald, William; Cowan, Conrad L; Crombie, Aimee L; Violin, Jonathan D; Lark, Michael W

2017-08-01

Prescription opioids are a mainstay in the treatment of acute moderate to severe pain. However, chronic use leads to a host of adverse consequences including tolerance and opioid-induced hyperalgesia (OIH), leading to more complex treatment regimens and diminished patient compliance. Patients with OIH paradoxically experience exaggerated nociceptive responses instead of pain reduction after chronic opioid usage. The development of OIH and tolerance tend to occur simultaneously and, thus, present a challenge when studying the molecular mechanisms driving each phenomenon. We tested the hypothesis that a G protein-biased µ -opioid peptide receptor (MOPR) agonist would not induce symptoms of OIH, such as mechanical allodynia, following chronic administration. We observed that the development of opioid-induced mechanical allodynia (OIMA), a model of OIH, was absent in β -arrestin1 -/- and β -arrestin2 -/- mice in response to chronic administration of conventional opioids such as morphine, oxycodone and fentanyl, whereas tolerance developed independent of OIMA. In agreement with the β -arrestin knockout mouse studies, chronic administration of TRV0109101, a G protein-biased MOPR ligand and structural analog of oliceridine, did not promote the development of OIMA but did result in drug tolerance. Interestingly, following induction of OIMA by morphine or fentanyl, TRV0109101 was able to rapidly reverse allodynia. These observations establish a role for β -arrestins in the development of OIH, independent of tolerance, and suggest that the use of G protein-biased MOPR ligands, such as oliceridine and TRV0109101, may be an effective therapeutic avenue for managing chronic pain with reduced propensity for opioid-induced hyperalgesia. Copyright © 2017 by The American Society for Pharmacology and Experimental Therapeutics.

Endogene opioider og deres terapeutiske anvendelse i smertebehandling

DEFF Research Database (Denmark)

Juul, A; Pedersen, A T

1990-01-01

Cancer patients with chronic pain and obstetric patients have participated in clinical trials of the analgesic effects of endogenous opioids. It is possible to achieve adequate relief of pain in these patients following epidural or intrathecal administration of endogenous opioids. Further investi...

Brain catalase activity inhibition as well as opioid receptor antagonism increases ethanol-induced HPA axis activation.

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Pastor, Raúl; Sanchis-Segura, Carles; Aragon, Carlos M G

2004-12-01

Growing evidence indicates that brain catalase activity is involved in the psychopharmacological actions of ethanol. Recent data suggest that participation of this enzymatic system in some ethanol effects could be mediated by the endogenous opioid system. The present study assessed whether brain catalase has a role in ethanol-induced activation of the HPA axis, a neuroendocrine system modulated by the endogenous opioid neurotransmission. Swiss male mice received an intraperitoneal injection of the catalase inhibitor 3-amino-1,2,4-triazole (AT; 0-1 g/kg), and 0 to 20 hr after this administration, animals received an ethanol (0-4 g/kg; intraperitoneally) challenge. Thirty, 60, or 120 min after ethanol administration, plasma corticosterone levels were determined immunoenzymatically. In addition, we tested the effects of 45 mg/kg of cyanamide (another catalase inhibitor) and 0 to 2 mg/kg of naltrexone (nonselective opioid receptor antagonist) on ethanol-induced enhancement in plasma corticosterone values. The present study revealed that AT boosts ethanol-induced increase in plasma corticosterone levels in a dose- and time-dependent manner. However, it did not affect corticosterone values when measured after administration of saline, cocaine (4 mg/kg, intraperitoneally), or morphine (30 mg/kg, intraperitoneally). The catalase inhibitor cyanamide (45 mg/kg, intraperitoneally) also increased ethanol-related plasma corticosterone levels. These effects of AT and cyanamide on ethanol-induced corticosterone values were observed under treatment conditions that decreased significantly brain catalase activity. Indeed, a significant correlation between effects of catalase manipulations on both variables was found. Finally, we found that the administration of naltrexone enhanced the levels of plasma corticosterone after the administration of saline or ethanol. This study shows that the inhibition of brain catalase increases ethanol-induced plasma corticosterone levels. Results are

Opioid Epidemic: Cellular & Molecular Anesthesia as a Key Solution

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Ali Dabbagh

2017-12-01

Full Text Available Opioids are one of the most important arsenals armamentarium of physicians for fighting against pain. During the decades, opioids have been used in a wide range of indications; both for treatment of acute and chronic pain; as natural and synthetic compounds and in a variety of delivery forms from intravenous infusion to intrathecal adjuvants of local anesthetics or as transdermal patches. There is no doubt that we are in an opioid misuse epidemic status; whether in the US or other countries; but if we want to resolve this miserable multilateral complication, there is no doubt that Cellular and Molecular aspects of Anesthesia has a key role in resolving the problem; through creating an opioid free pain management era.

A brain-targeted ampakine compound protects against opioid-induced respiratory depression.

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Dai, Wei; Xiao, Dian; Gao, Xiang; Zhou, Xin-Bo; Fang, Tong-Yu; Yong, Zheng; Su, Rui-Bin

2017-08-15

The use of opioid drugs for pain relief can induce life-threatening respiratory depression. Although naloxone effectively counteracts opioid-induced respiratory depression, it diminishes the efficacy of analgesia. Our studies indicate that ampakines, in particular, a brain-targeted compound XD-8-17C, are able to reverse respiratory depression without affecting analgesia at relatively low doses. Mice and rats were subcutaneously or intravenously injected with the opioid agonist TH-030418 to induce moderate or severe respiratory depression. XD-8-17C was intravenously administered before or after TH-030418. The effect of XD-8-17C on opioid-induced respiratory depression was evaluated in terms of the opioid-induced acute death rate, arterial blood gas analysis and pulmonary function tests. In addition, the hot-plate test was conducted to investigate whether XD-8-17C influenced opioid-induced analgesia. Pre-treatment with XD-8-17C significantly reduced opioid-induced acute death, and increased the median lethal dose of TH-030418 by 4.7-fold. Blood gas analysis and pulmonary function tests demonstrated that post-treatment with XD-8-17C alleviated respiratory depression, as indicated by restoration of arterial blood gas (pO 2 , sO 2 , cK + ) and lung function parameters (respiratory frequency, minute ventilation) to the normal range. The hot-plate test showed that XD-8-17C had no impact on the antinociceptive efficacy of morphine. The ability of XD-8-17C to reverse opioid-induced respiratory depression has the potential to increase the safety and convenience of opioid treatment. These findings contribute to the discovery of novel therapeutic agents that protect against opioid-induced respiratory depression without loss of analgesia. Copyright © 2017 Elsevier B.V. All rights reserved.

β-Arrestin-2 knockout prevents development of cellular μ-opioid receptor tolerance but does not affect opioid-withdrawal-related adaptations in single PAG neurons.

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Connor, M; Bagley, E E; Chieng, B C; Christie, M J

2015-01-01

Tolerance to the behavioural effects of morphine is blunted in β-arrestin-2 knockout mice, but opioid withdrawal is largely unaffected. The cellular mechanisms of tolerance have been studied in some neurons from β-arrestin-2 knockouts, but tolerance and withdrawal mechanisms have not been examined at the cellular level in periaqueductal grey (PAG) neurons, which are crucial for central tolerance and withdrawal phenomena. μ-Opioid receptor (MOPr) inhibition of voltage-gated calcium channel currents (ICa ) was examined by patch-clamp recordings from acutely dissociated PAG neurons from wild-type and β-arrestin-2 knockout mice treated chronically with morphine (CMT) or vehicle. Opioid withdrawal-induced activation of GABA transporter type 1 (GAT-1) currents was determined using perforated patch recordings from PAG neurons in brain slices. MOPr inhibition of ICa in PAG neurons was unaffected by β-arrestin-2 deletion. CMT impaired coupling of MOPrs to ICa in PAG neurons from wild-type mice, but this cellular tolerance was not observed in neurons from CMT β-arrestin-2 knockouts. However, β-arrestin-2 knockouts displayed similar opioid-withdrawal-induced activation of GAT-1 currents as wild-type PAG neurons. In β-arrestin-2 knockout mice, the central neurons involved in the anti-nociceptive actions of opioids also fail to develop cellular tolerance to opioids following chronic morphine. The results also provide the first cellular physiological evidence that opioid withdrawal is not disrupted by β-arrestin-2 deletion. However, the unaffected basal sensitivity to opioids in PAG neurons provides further evidence that changes in basal MOPr sensitivity cannot account for the enhanced acute nociceptive response to morphine reported in β-arrestin-2 knockouts. This article is part of a themed section on Opioids: New Pathways to Functional Selectivity. To view the other articles in this section visit http://dx.doi.org/10.1111/bph.2015.172.issue-2. © 2014 The British

Opioid shopping behavior: how often, how soon, which drugs, and what payment method.

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Cepeda, M Soledad; Fife, Daniel; Chow, Wing; Mastrogiovanni, Gregory; Henderson, Scott C

2013-01-01

Doctor shopping (obtaining opioid prescriptions from multiple prescribers) is one example of opioid abuse and diversion. The authors assessed how soon shopping behavior was observed after opioid exposure, number of events per shopper, preferred opioids, and method of payment. This was a cohort study. Individuals with ≤1 dispensing for any opioid in 2008 were followed for 18 months. Shopping behavior was defined as ≤2 prescriptions by different prescribers with ≤1 day of overlap and filled at ≤3 pharmacies. Of 25,161,024 subjects, 0.30% exhibited shopping behavior. Opioid-experienced subjects were 13.7 times more likely to exhibit shopping behavior and had more shopping episodes than opioid-naive subjects. Time to first shopping event was 246.90 ± 163.61 days. Number of episodes was 2.74 ± 4.66. Most subjects with shopping behavior (55.27%) had 1 shopping episode, whereas 9.52% had ≤6 episodes; 88.99% had ≤4 prescribers. Subjects with shopping behavior filled schedule II opioids more often than subjects without shopping behavior (19.51% vs 10.89%) and more often paid in cash (44.85% vs 18.54%). Three of 1000 people exposed to opioids exhibit shopping behavior, on average, 8 months after exposure. Opioid shoppers seek strong opioids, avoid combination products, often pay cash, and obtain prescriptions from few prescribers. © 2012 The Author(s).

Thallium exists in opioid poisoned patients.

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Ghaderi, Amir; Vahdati-Mashhadian, Naser; Oghabian, Zohreh; Moradi, Valiallah; Afshari, Reza; Mehrpour, Omid

2015-08-01

Thallium (Tl) is a toxic heavy metal that exists in nature. Tl poisoning (thallotoxicosis) may occur in opioid addicts. This study was designed to evaluate the frequency and level of urinary Tl in opioid abusers. In addition, clinical findings were evaluated. A total of 150 subjects were examined. Cases with a history of at least 3 years of abuse were admitted in the Imam Reza Hospital as the case group; 50 non-opioid abusers from the target population were included as the control group. Twenty-four hour urinary qualitative and quantitative Tl analyses were performed on both groups. Out of the 150 subjects, 128 (85 %) were negative for qualitative urinary Tl, followed by 5 % (trace), 7 % (1+), 2 % (2+), and 1 % (3+). Mean (standard error (SE), Min-Max) quantitative urinary Tl level was 14 μg/L (3.5 μg/L, 0-346 μg/L). Mean urinary Tl level in the case group was 21 μg/L (5 μg/L, 0-346 μg/L) and that in the controls was 1 μg/L (0.14 μg/L, 0-26 μg/L), which were significantly different (P = 0.001). The most frequent clinical findings were ataxia (86 %), sweating (81 %), and constipation (54 %). In all cases (n = 150), the mean (SE) value for cases with positive qualitative urinary Tl was 26.8 μg/L (0.9 μg/L) and that in the negative cases was 2.3 μg/L (0.2 μg/L), which were significantly different (P = 0.002). This study showed that long-term opioid abuse may lead to Tl exposure. In opioid abusers with the clinical manifestation of thallotoxicosis, urinary Tl should be determined.

Contribution of NMDA receptor hypofunction in prefrontal and cortical excitatory neurons to schizophrenia-like phenotypes.

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Gregory R Rompala

Full Text Available Pharmacological and genetic studies support a role for NMDA receptor (NMDAR hypofunction in the etiology of schizophrenia. We have previously demonstrated that NMDAR obligatory subunit 1 (GluN1 deletion in corticolimbic interneurons during early postnatal development is sufficient to confer schizophrenia-like phenotypes in mice. However, the consequence of NMDAR hypofunction in cortical excitatory neurons is not well delineated. Here, we characterize a conditional knockout mouse strain (CtxGluN1 KO mice, in which postnatal GluN1 deletion is largely confined to the excitatory neurons in layer II/III of the medial prefrontal cortex and sensory cortices, as evidenced by the lack of GluN1 mRNA expression in in situ hybridization immunocytochemistry as well as the lack of NMDA currents with in vitro recordings. Mutants were impaired in prepulse inhibition of the auditory startle reflex as well as object-based short-term memory. However, they did not exhibit impairments in additional hallmarks of schizophrenia-like phenotypes (e.g. spatial working memory, social behavior, saccharine preference, novelty and amphetamine-induced hyperlocomotion, and anxiety-related behavior. Furthermore, upon administration of the NMDA receptor antagonist, MK-801, there were no differences in locomotor activity versus controls. The mutant mice also showed negligible levels of reactive oxygen species production following chronic social isolation, and recording of miniature-EPSC/IPSCs from layer II/III excitatory neurons in medial prefrontal cortex suggested no alteration in GABAergic activity. All together, the mutant mice displayed cognitive deficits in the absence of additional behavioral or cellular phenotypes reflecting schizophrenia pathophysiology. Thus, NMDAR hypofunction in prefrontal and cortical excitatory neurons may recapitulate only a cognitive aspect of human schizophrenia symptoms.

Contribution of NMDA receptor hypofunction in prefrontal and cortical excitatory neurons to schizophrenia-like phenotypes.

Science.gov (United States)

Rompala, Gregory R; Zsiros, Veronika; Zhang, Shuqin; Kolata, Stefan M; Nakazawa, Kazu

2013-01-01

Pharmacological and genetic studies support a role for NMDA receptor (NMDAR) hypofunction in the etiology of schizophrenia. We have previously demonstrated that NMDAR obligatory subunit 1 (GluN1) deletion in corticolimbic interneurons during early postnatal development is sufficient to confer schizophrenia-like phenotypes in mice. However, the consequence of NMDAR hypofunction in cortical excitatory neurons is not well delineated. Here, we characterize a conditional knockout mouse strain (CtxGluN1 KO mice), in which postnatal GluN1 deletion is largely confined to the excitatory neurons in layer II/III of the medial prefrontal cortex and sensory cortices, as evidenced by the lack of GluN1 mRNA expression in in situ hybridization immunocytochemistry as well as the lack of NMDA currents with in vitro recordings. Mutants were impaired in prepulse inhibition of the auditory startle reflex as well as object-based short-term memory. However, they did not exhibit impairments in additional hallmarks of schizophrenia-like phenotypes (e.g. spatial working memory, social behavior, saccharine preference, novelty and amphetamine-induced hyperlocomotion, and anxiety-related behavior). Furthermore, upon administration of the NMDA receptor antagonist, MK-801, there were no differences in locomotor activity versus controls. The mutant mice also showed negligible levels of reactive oxygen species production following chronic social isolation, and recording of miniature-EPSC/IPSCs from layer II/III excitatory neurons in medial prefrontal cortex suggested no alteration in GABAergic activity. All together, the mutant mice displayed cognitive deficits in the absence of additional behavioral or cellular phenotypes reflecting schizophrenia pathophysiology. Thus, NMDAR hypofunction in prefrontal and cortical excitatory neurons may recapitulate only a cognitive aspect of human schizophrenia symptoms.

Intraoperative ketamine reduces immediate postoperative opioid consumption after spinal fusion surgery in chronic pain patients with opioid dependency

DEFF Research Database (Denmark)

Nielsen, Rikke Vibeke; Fomsgaard, Jonna Storm; Siegel, Hanna

2017-01-01

Perioperative handling of surgical patients with opioid dependency represents an important clinical problem. Animal studies suggest that ketamine attenuates central sensitization and hyperalgesia and thereby reduces postoperative opioid tolerance. We hypothesized that intraoperative ketamine would...... to 24 hours postoperatively (visual analogue scale), adverse events, and persistent pain 6 months postoperatively. One hundred fifty patients were randomly assigned to intraoperative S-ketamine bolus 0.5 mg/kg and infusion 0.25 mg·kg·h or placebo. Postoperatively, patients received their usual opioids......, paracetamol and IV patient-controlled analgesia with morphine. In the final analyses, 147 patients were included. Patient-controlled analgesia IV morphine consumption 0 to 24 hours postoperatively was significantly reduced in the ketamine group compared with the placebo group: 79 (47) vs 121 (53) mg IV, mean...

Glycine receptors support excitatory neurotransmitter release in developing mouse visual cortex

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Kunz, Portia A; Burette, Alain C; Weinberg, Richard J; Philpot, Benjamin D

2012-01-01

Glycine receptors (GlyRs) are found in most areas of the brain, and their dysfunction can cause severe neurological disorders. While traditionally thought of as inhibitory receptors, presynaptic-acting GlyRs (preGlyRs) can also facilitate glutamate release under certain circumstances, although the underlying molecular mechanisms are unknown. In the current study, we sought to better understand the role of GlyRs in the facilitation of excitatory neurotransmitter release in mouse visual cortex. Using whole-cell recordings, we found that preGlyRs facilitate glutamate release in developing, but not adult, visual cortex. The glycinergic enhancement of neurotransmitter release in early development depends on the high intracellular to extracellular Cl− gradient maintained by the Na+–K+–2Cl− cotransporter and requires Ca2+ entry through voltage-gated Ca2+ channels. The glycine transporter 1, localized to glial cells, regulates extracellular glycine concentration and the activation of these preGlyRs. Our findings demonstrate a developmentally regulated mechanism for controlling excitatory neurotransmitter release in the neocortex. PMID:22988142

Clinical implications of patient-provider agreements in opioid prescribing.

Science.gov (United States)

Kraus, Carl N; Baldwin, Alan T; Curro, Frederick A; McAllister, R G

2015-01-01

In June, 2012 the United States Food and Drug Administration (FDA) developed a "blueprint" for prescriber education as a means of directing Certified Medical Education (CME) activities that included content which would meet the regulatory requirements of the class-wide, longacting/ extended-release (LA-ER) opioid Risk Evaluation Mitigation Strategies (REMS). Within the blueprint is the suggested adoption of Patient-Provider Agreements (PPAs) to be used in association with opioid prescribing, but, to our knowledge, there have been no reported evaluations of the role played by opioid-agent PPAs in clinical practice, or of the perceptions of this regulatory mandate by clinicians. Therefore, we conducted a survey regarding PPA perceptions by opioid prescribers that was posted for five weeks on a well-trafficked online CME service provider (Medscape). Of the 1,232 respondents (reflecting a 99.5% completion rate), 52.4% treat acute or chronic pain with opioids. The survey identified an improvement of opioid safe-use education (21% of respondents) as the most frequently selected beneficial element of PPAs. Conversely, the challenges to adoption included time constraints (21% of physicians) as well as lack of evidence that PPAs will reduce drug misuse, and the lack of a uniform, patient-friendly PPA. Based on our survey, clinicians consider the PPA of potential value, but data regarding the utility of such an instrument are lacking.

Age-related decreased inhibitory vs. excitatory gene expression in the adult autistic brain

NARCIS (Netherlands)

van de Lagemaat, Louie N; Nijhof, Bonnie; Bosch, Daniëlle G M; Kohansal-Nodehi, Mahdokht; Keerthikumar, Shivakumar; Heimel, J.A.

2014-01-01

Autism spectrum disorders (ASDs) are neurodevelopmental disorders characterized by impaired social interaction and communication, and restricted behavior and interests. A disruption in the balance of excitatory and inhibitory neurotransmission has been hypothesized to underlie these disorders. Here

A new and novel treatment of opioid dependence: nigella sativa 500 mg

International Nuclear Information System (INIS)

Sangi, S.; Ahmed, S.P.; Channa, M.A.

2008-01-01

Opioid dependence is one of the major social and psychiatric problem of society. Unfortunately there is no non opiate treatment available. For centuries man has used plants for their healing proprieties. These plants play a fundamental part in all treatment modalities, both ancient and modern. This study was conducted to find non opiate treatment for opiate withdrawal. Total 35 known addicts of opiates were included in the study. This study was based on DSM IV criteria for opioid dependence. This study demonstrates that non opioid treatment for opioid addiction decreases the withdrawal effects significantly. It further demonstrates that there are no changes in physiological parameters of subjects during treatment (BP, Pulse rate etc.). There is increased appetite but no significant weight gain in the subjects. Non opioid drug Nigella sativa is effective in long term treatment of opioid dependence. It not merely cures the opioid dependence but also cures the infections and weakness from which majority of addicts suffer. (author)

Advances in the delivery of buprenorphine for opioid dependence

Directory of Open Access Journals (Sweden)

Rosenthal RN

2017-08-01

Full Text Available Richard N Rosenthal,1 Viral V Goradia2 1Department of Psychiatry, Addiction Institute at Mount Sinai, Icahn School of Medicine at Mount Sinai, New York, 2Department of Psychiatry, Upstate Medical University, Syracuse, NY, USA Abstract: Opioid use disorders (OUDs have long been a global problem, but the prevalence rates have increased over 20 years to epidemic proportions in the US, with concomitant increases in morbidity and all-cause mortality, but especially opioid overdose. These increases are in part attributable to a several-fold expansion in the prescription of opioid pain medications over the same time period. Opioid detoxification and psychosocial treatments alone have each not yielded sufficient efficacy for OUD, but μ-opioid receptor agonist, partial agonist, and antagonist medications have demonstrated the greatest overall benefit in OUD treatment. Buprenorphine, a μ-opioid receptor partial agonist, has been used successfully on an international basis for several decades in sublingual tablet and film preparations for the treatment of OUD, but the nature of formulation, which is typically self-administered, renders it susceptible to nonadherence, diversion, and accidental exposure. This article reviews the clinical trial data for novel buprenorphine delivery systems in the form of subcutaneous depot injections, transdermal patches, and subdermal implants for the treatment of OUD and discusses both the clinical efficacy of longer-acting formulations through increasing consistent medication exposure and their potential utility in reducing diversion. These new delivery systems also offer new dosing opportunities for buprenorphine and strategies for dosing intervals in the treatment of OUD. Keywords: opioid use disorder, buprenorphine, drug diversion, drug implants, depot medications, maintenance therapy, treatment adherence

A Conceptual Framework for Understanding Unintended Prolonged Opioid Use.

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Hooten, W Michael; Brummett, Chad M; Sullivan, Mark D; Goesling, Jenna; Tilburt, Jon C; Merlin, Jessica S; St Sauver, Jennifer L; Wasan, Ajay D; Clauw, Daniel J; Warner, David O

2017-12-01

An urgent need exists to better understand the transition from short-term opioid use to unintended prolonged opioid use (UPOU). The purpose of this work is to propose a conceptual framework for understanding UPOU that posits the influence of 3 principal domains that include the characteristics of (1) individual patients, (2) the practice environment, and (3) opioid prescribers. Although no standardized method exists for developing a conceptual framework, the process often involves identifying corroborative evidence, leveraging expert opinion to identify factors for inclusion in the framework, and developing a graphic depiction of the relationships between the various factors and the clinical problem of interest. Key patient characteristics potentially associated with UPOU include (1) medical and mental health conditions; (2) pain etiology; (3) individual affective, behavioral, and neurophysiologic reactions to pain and opioids; and (4) sociodemographic factors. Also, UPOU could be influenced by structural and health care policy factors: (1) the practice environment, including the roles of prescribing clinicians, adoption of relevant practice guidelines, and clinician incentives or disincentives, and (2) the regulatory environment. Finally, characteristics inherent to clinicians that could influence prescribing practices include (1) training in pain management and opioid use; (2) personal attitudes, knowledge, and beliefs regarding the risks and benefits of opioids; and (3) professionalism. As the gatekeeper to opioid access, the behavior of prescribing clinicians directly mediates UPOU, with the 3 domains interacting to determine this behavior. This proposed conceptual framework could guide future research on the topic and allow plausible hypothesis-based interventions to reduce UPOU. Copyright © 2017 Mayo Foundation for Medical Education and Research. Published by Elsevier Inc. All rights reserved.

Intrinsically-generated fluctuating activity in excitatory-inhibitory networks

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Mastrogiuseppe, Francesca; Ostojic, Srdjan

2017-01-01

Recurrent networks of non-linear units display a variety of dynamical regimes depending on the structure of their synaptic connectivity. A particularly remarkable phenomenon is the appearance of strongly fluctuating, chaotic activity in networks of deterministic, but randomly connected rate units. How this type of intrinsically generated fluctuations appears in more realistic networks of spiking neurons has been a long standing question. To ease the comparison between rate and spiking networks, recent works investigated the dynamical regimes of randomly-connected rate networks with segregated excitatory and inhibitory populations, and firing rates constrained to be positive. These works derived general dynamical mean field (DMF) equations describing the fluctuating dynamics, but solved these equations only in the case of purely inhibitory networks. Using a simplified excitatory-inhibitory architecture in which DMF equations are more easily tractable, here we show that the presence of excitation qualitatively modifies the fluctuating activity compared to purely inhibitory networks. In presence of excitation, intrinsically generated fluctuations induce a strong increase in mean firing rates, a phenomenon that is much weaker in purely inhibitory networks. Excitation moreover induces two different fluctuating regimes: for moderate overall coupling, recurrent inhibition is sufficient to stabilize fluctuations; for strong coupling, firing rates are stabilized solely by the upper bound imposed on activity, even if inhibition is stronger than excitation. These results extend to more general network architectures, and to rate networks receiving noisy inputs mimicking spiking activity. Finally, we show that signatures of the second dynamical regime appear in networks of integrate-and-fire neurons. PMID:28437436

Examining the role of mu opioid receptor endocytosis in the beneficial and side-effects of prolonged opioid use: From a symposium on new concepts in mu-opioid pharmacology

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Whistler, Jennifer L.

2012-01-01

Opioid drugs remain the gold standard for the treatment of severe pain, both acute/post-surgical and chronic. However, the utility of opioid drugs for the treatment of chronic pain is compromised by the development of analgesic tolerance which, in turn, leads to dose-escalation and increased likelihood of dangerous side effects, including dependence. Consequently, there remains resistance among clinicians and the general population to using opiates for pain management because of risk of “addi...

Endogenous Opioid Function and Responses to Morphine: The Moderating Effects of Anger Expressiveness.

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Burns, John W; Bruehl, Stephen; France, Christopher R; Schuster, Erik; Orlowska, Daria; Chont, Melissa; Gupta, Rajnish K; Buvanendran, Asokumar

2017-08-01

Long-term use of opioid analgesics may be ineffective or associated with significant negative side effects for some people. At present, there is no sound method of identifying optimal opioid candidates. Individuals with chronic low back pain (n = 89) and healthy control individuals (n = 102) underwent ischemic pain induction with placebo, opioid blockade (naloxone), and morphine in counterbalanced order. They completed the Spielberger Anger-Out subscale. Endogenous opioid function × Anger-out × Pain status (chronic pain, healthy control) interactions were tested for morphine responses to ischemic threshold, tolerance, and pain intensity (McGill Sensory and Affective subscales) and side effects. For individuals with chronic pain and healthy control participants, those with low endogenous opioid function and low anger-out scores exhibited the largest morphine analgesic responses, whereas those with high anger-out and low endogenous opioid function showed relatively weaker morphine analgesic responses. Further, individuals with chronic pain with low endogenous opioid function and low anger-out scores also reported the fewest negative effects to morphine, whereas those with low endogenous opioid function and high anger-out reported the most. Findings point toward individuals with chronic pain who may strike a favorable balance of good analgesia with few side effects, as well as those who have an unfavorable balance of poor analgesia and many side effects. We sought to identify optimal candidates for opioid pain management. Low back pain patients who express anger and also have deficient endogenous opioid function may be poor candidates for opioid therapy. In contrast, low back patients who tend not to express anger and who also have deficient endogenous opioid function may make optimal candidates for opioid therapy. Copyright © 2017 American Pain Society. Published by Elsevier Inc. All rights reserved.

Social Laughter Triggers Endogenous Opioid Release in Humans.

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Manninen, Sandra; Tuominen, Lauri; Dunbar, Robin I; Karjalainen, Tomi; Hirvonen, Jussi; Arponen, Eveliina; Hari, Riitta; Jääskeläinen, Iiro P; Sams, Mikko; Nummenmaa, Lauri

2017-06-21

The size of human social networks significantly exceeds the network that can be maintained by social grooming or touching in other primates. It has been proposed that endogenous opioid release after social laughter would provide a neurochemical pathway supporting long-term relationships in humans (Dunbar, 2012), yet this hypothesis currently lacks direct neurophysiological support. We used PET and the μ-opioid-receptor (MOR)-specific ligand [ 11 C]carfentanil to quantify laughter-induced endogenous opioid release in 12 healthy males. Before the social laughter scan, the subjects watched laughter-inducing comedy clips with their close friends for 30 min. Before the baseline scan, subjects spent 30 min alone in the testing room. Social laughter increased pleasurable sensations and triggered endogenous opioid release in thalamus, caudate nucleus, and anterior insula. In addition, baseline MOR availability in the cingulate and orbitofrontal cortices was associated with the rate of social laughter. In a behavioral control experiment, pain threshold-a proxy of endogenous opioidergic activation-was elevated significantly more in both male and female volunteers after watching laughter-inducing comedy versus non-laughter-inducing drama in groups. Modulation of the opioidergic activity by social laughter may be an important neurochemical pathway that supports the formation, reinforcement, and maintenance of human social bonds. SIGNIFICANCE STATEMENT Social contacts are vital to humans. The size of human social networks significantly exceeds the network that can be maintained by social grooming in other primates. Here, we used PET to show that endogenous opioid release after social laughter may provide a neurochemical mechanism supporting long-term relationships in humans. Participants were scanned twice: after a 30 min social laughter session and after spending 30 min alone in the testing room (baseline). Endogenous opioid release was stronger after laughter versus the

Dynamics of excitatory and inhibitory networks are differentially altered by selective attention

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Snyder, Adam C.; Morais, Michael J.

2016-01-01

Inhibition and excitation form two fundamental modes of neuronal interaction, yet we understand relatively little about their distinct roles in service of perceptual and cognitive processes. We developed a multidimensional waveform analysis to identify fast-spiking (putative inhibitory) and regular-spiking (putative excitatory) neurons in vivo and used this method to analyze how attention affects these two cell classes in visual area V4 of the extrastriate cortex of rhesus macaques. We found that putative inhibitory neurons had both greater increases in firing rate and decreases in correlated variability with attention compared with putative excitatory neurons. Moreover, the time course of attention effects for putative inhibitory neurons more closely tracked the temporal statistics of target probability in our task. Finally, the session-to-session variability in a behavioral measure of attention covaried with the magnitude of this effect. Together, these results suggest that selective targeting of inhibitory neurons and networks is a critical mechanism for attentional modulation. PMID:27466133

Dynamics of excitatory and inhibitory networks are differentially altered by selective attention.

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Snyder, Adam C; Morais, Michael J; Smith, Matthew A

2016-10-01

Inhibition and excitation form two fundamental modes of neuronal interaction, yet we understand relatively little about their distinct roles in service of perceptual and cognitive processes. We developed a multidimensional waveform analysis to identify fast-spiking (putative inhibitory) and regular-spiking (putative excitatory) neurons in vivo and used this method to analyze how attention affects these two cell classes in visual area V4 of the extrastriate cortex of rhesus macaques. We found that putative inhibitory neurons had both greater increases in firing rate and decreases in correlated variability with attention compared with putative excitatory neurons. Moreover, the time course of attention effects for putative inhibitory neurons more closely tracked the temporal statistics of target probability in our task. Finally, the session-to-session variability in a behavioral measure of attention covaried with the magnitude of this effect. Together, these results suggest that selective targeting of inhibitory neurons and networks is a critical mechanism for attentional modulation. Copyright © 2016 the American Physiological Society.

Opioid Summaries by State

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... Alcohol Club Drugs Cocaine Fentanyl Hallucinogens Inhalants Heroin Marijuana MDMA (Ecstasy/Molly) Methamphetamine Opioids Over-the-Counter Medicines Prescription Medicines Steroids (Anabolic) Synthetic Cannabinoids (K2/Spice) Synthetic Cathinones (Bath Salts) Tobacco/ ...

Intrathecal opioids versus epidural local anesthetics for labor analgesia: a meta-analysis.

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Bucklin, Brenda A; Chestnut, David H; Hawkins, Joy L

2002-01-01

Some anesthesiologists contend that intrathecal opioid administration has advantages over conventional epidural techniques during labor. Randomized clinical trials comparing analgesia and obstetric outcome using single-injection intrathecal opioids versus epidural local anesthetics suggest that intrathecal opioids provide comparable analgesia with few serious side effects. This meta-analysis compared the analgesic efficacy, side effects, and obstetric outcome of single-injection intrathecal opioid techniques versus epidural local anesthetics in laboring women. Relevant clinical studies were identified using electronic and manual searches of the literature covering the period from 1989 to 2000. Searches used the following descriptors: intrathecal analgesia, spinal opioids, epidural analgesia, epidural local anesthetics, and analgesia for labor. Data were extracted from 7 randomized clinical trials comparing analgesic measures, incidence of motor block, pruritus, nausea, hypotension, mode of delivery, and/or Apgar scores. Combined test results indicated comparable analgesic efficacy 15 to 20 minutes after injection with single-injection intrathecal opioid administration. Intrathecal opioid injections were associated with a greater incidence of pruritus (odds ratio, 14.01; 99% confidence interval, 6.9 to 28.3), but there was no difference in the incidence of nausea or in the method of delivery. Published studies suggest that intrathecal opioids provide comparable early labor analgesia when compared with epidural local anesthetics. Intrathecal opioid administration results in a greater incidence of pruritus. The choice of technique does not appear to affect the method of delivery.

Glucose Rapidly Induces Different Forms of Excitatory Synaptic Plasticity in Hypothalamic POMC Neurons

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Hu, Jun; Jiang, Lin; Low, Malcolm J.; Rui, Liangyou

2014-01-01

Hypothalamic POMC neurons are required for glucose and energy homeostasis. POMC neurons have a wide synaptic connection with neurons both within and outside the hypothalamus, and their activity is controlled by a balance between excitatory and inhibitory synaptic inputs. Brain glucose-sensing plays an essential role in the maintenance of normal body weight and metabolism; however, the effect of glucose on synaptic transmission in POMC neurons is largely unknown. Here we identified three types of POMC neurons (EPSC(+), EPSC(−), and EPSC(+/−)) based on their glucose-regulated spontaneous excitatory postsynaptic currents (sEPSCs), using whole-cell patch-clamp recordings. Lowering extracellular glucose decreased the frequency of sEPSCs in EPSC(+) neurons, but increased it in EPSC(−) neurons. Unlike EPSC(+) and EPSC(−) neurons, EPSC(+/−) neurons displayed a bi-phasic sEPSC response to glucoprivation. In the first phase of glucoprivation, both the frequency and the amplitude of sEPSCs decreased, whereas in the second phase, they increased progressively to the levels above the baseline values. Accordingly, lowering glucose exerted a bi-phasic effect on spontaneous action potentials in EPSC(+/−) neurons. Glucoprivation decreased firing rates in the first phase, but increased them in the second phase. These data indicate that glucose induces distinct excitatory synaptic plasticity in different subpopulations of POMC neurons. This synaptic remodeling is likely to regulate the sensitivity of the melanocortin system to neuronal and hormonal signals. PMID:25127258

The effects of opioid drugs on dopamine mediated locomotor activity in rats

International Nuclear Information System (INIS)

Leathern, L.L.

1986-12-01

Opioid drugs influence various behavioural parameters including locomotor activity in experimental animals. The interaction between the opioid and dopaminergic systems is one possible explanation for the effect of opioid drugs on locomotor activity. In this study behavioural and biochemical assays were done to investigate the interaction between the opioid and dopaminergic systems. Behavioural studies were done by measurement of locomotor activity (LA) of rats after acute or chronic pretreatment with opioid and/or dopaminergic drugs. Biochemical studies were in the form of radioligand binding assays, the effect on the number (Bmax) and affinity (K D ) of receptors was measured after chronic pretreatment with opioid and/or dopaminergic drugs. The opioid drugs used are morphine, nalbuphine and naloxone. Dopaminergic drugs used included: agonists-apomorphine and piribedil; antagonists-pimozide, haloperidol, chlorpromazine. In the acute situation increased LA was obtained with morphine and the DA agonists. A correlation between the behavioural and biochemical assays was found. Chronic pretreatment with morphine enhanced apomorphine induced LA, this supersensitivity was also measured as an increased receptor density (Bmax) of D2 receptors in the striatum. Chronic morphine pretreatment caused a decrease in morphine induced LA, while this subsensitivity was not apparent in the ligand binding assays - where no change in receptor number was observed. Chronic naloxone pretreatment enhanced morphine induced LA, as well as increased the Bmax of opioid receptors in the whole brain. It is concluded that an interaction between the opioid and dopaminergic systems does exist, and may account for the mechanism of action of the opioids

Prevalence of Long-Term Opioid Use in Long-Stay Nursing Home Residents.

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Hunnicutt, Jacob N; Chrysanthopoulou, Stavroula A; Ulbricht, Christine M; Hume, Anne L; Tjia, Jennifer; Lapane, Kate L

2018-01-01

Overall and long-term opioid use among older adults have increased since 1999. Less is known about opioid use in older adults in nursing homes (NHs). Cross-sectional. U.S. NHs (N = 13,522). Long-stay NH resident Medicare beneficiaries with a Minimum Data Set 3.0 (MDS) assessment between April 1, 2012, and June 30, 2012, and 120 days of follow-up (N = 315,949). We used Medicare Part D claims to measure length of opioid use in the 120 days from the index assessment (short-term: ≤30 days, medium-term: >30-89 days, long-term: ≥90 days), adjuvants (e.g., anticonvulsants), and other pain medications (e.g., corticosteroids). MDS assessments in the follow-up period were used to measure nonpharmacological pain management use. Modified Poisson models were used to estimate adjusted prevalence ratios (aPR) and 95% confidence intervals (CI) for age, gender, race and ethnicity, cognitive and physical impairment, and long-term opioid use. Of all long-stay residents, 32.4% were prescribed any opioid, and 15.5% were prescribed opioids long-term. Opioid users (versus nonusers) were more commonly prescribed pain adjuvants (32.9% vs 14.9%), other pain medications (25.5% vs 11.0%), and nonpharmacological pain management (24.5% vs 9.3%). Long-term opioid use was higher in women (aPR = 1.21, 95% CI = 1.18-1.23) and lower in racial and ethnic minorities (non-Hispanic blacks vs whites: APR = 0.93, 95% CI = 0.90-0.94) and those with severe cognitive impairment (vs no or mild impairment, aPR = 0.82, 95% CI = 0.79-0.83). One in seven NH residents was prescribed opioids long-term. Recent guidelines on opioid prescribing for pain recommend reducing long-term opioid use, but this is challenging in NHs because residents may not benefit from nonpharmacological and nonopioid interventions. Studies to address concerns about opioid safety and effectiveness (e.g., on pain and functional status) in NHs are needed. © 2017, Copyright the Authors Journal compilation © 2017, The American Geriatrics

Development of concepts on the interaction of drugs with opioid receptors

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Kuzmina, N E; Kuzmin, V S

2011-02-28

The development of concepts on the molecular mechanisms of the action of medicinal drugs on the opioid receptors is briefly surveyed. The modern point of view on the mechanism of activation of opioid receptors is given based on the data from chimeric and site-directed mutagenesis of the cloned opioid receptors and the computer-aided simulations of the reception zone and ligand-receptor complexes. Three-dimensional models of the opioid pharmacophore derived by both conventional methods and a comparative analysis of molecular fields are described in detail.

Synthesis of opioid receptor imaging agent 7α-o-IA-DPN

International Nuclear Information System (INIS)

Wang Rongfu

1997-01-01

A new opioid receptor imaging agent is designed and synthesized. 7α-o-iodoallyl diprenorphine (7α-o-IA-DPN) was obtained in one step by radioiododestannylation, which involved in the selection of DPN as an opioid antagonist, the regioselective protection of the DPN phenol tertiary-OH using acetylation and the introduction of vinylstannane as prosthetic group into the tertiary alcohol group position in the 7α-side chain. The iodinated DPN derivation was possessed of high radiolabeled yield (>90%) with 80 TBq/mmol specific radioactivity and more than 95% radiochemical purity. In vitro opioid receptor binding analysis showed very high affinity (Ki = 0.4 nmol/L). This new radioiodinated opioid ligand is suitable for SPECT study of opioid receptor imaging

Reward systems and food intake: role of opioids.

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Gosnell, B A; Levine, A S

2009-06-01

Humans eat for many reasons, including the rewarding qualities of foods. A host of neurotransmitters have been shown to influence eating behavior and some of these appear to be involved in reward-induced eating. Endogenous opioid peptides and their receptors were first reported more than 30 years ago, and studies suggesting a role of opioids in the regulation of food intake date back nearly as far. Opioid agonists and antagonists have corresponding stimulatory and inhibitory effects on feeding. In addition to studies aimed at identifying the relevant receptor subtypes and sites of action within the brain, there has been a continuing interest in the role of opioids on diet/taste preferences, food reward, and the overlap of food reward with others types of reward. Data exist that suggest a role for opioids in the control of appetite for specific macronutrients, but there is also evidence for their role in the stimulation of intake based on already-existing diet or taste preferences and in controlling intake motivated by hedonics rather than by energy needs. Finally, various types of studies indicate an overlap between mechanisms mediating drug reward and palatable food reward. Preference or consumption of sweet substances often parallels the self-administration of several drugs of abuse, and under certain conditions, the termination of intermittent access to sweet substances produces symptoms that resemble those observed during opiate withdrawal. The overconsumption of readily available and highly palatable foods likely contributes to the growing rates of obesity worldwide. An understanding of the role of opioids in mediating food reward and promoting the overconsumption of palatable foods may provide insights into new approaches for preventing obesity.

Opioid use following gynecologic and pelvic reconstructive surgery.

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Hota, Lekha S; Warda, Hussein A; Haviland, Miriam J; Searle, Frances M; Hacker, Michele R

2017-09-09

Opioid use, addiction, and overdose are a growing epidemic in the USA. Our objective was to determine whether the amount of opioid medication prescribed following gynecologic and pelvic reconstructive surgery is insufficient, adequate, or in excess. We hypothesized that we were overprescribing postoperative opioids. Participants who were at least 18 years old and underwent gynecologic and/or pelvic reconstructive surgery from April through August 2016 were eligible to participate. Routine practice for pain management is to prescribe 30 tablets of opioids for major procedures and ten to 15 tablets for minor procedures. At the 2-week postoperative visit, participants completed a questionnaire regarding the number of tablets prescribed and used, postoperative pain control, and relevant medical history. Fisher's exact test was used to compare data. Sixty-five participants completed questionnaires. Half (49.1%) reported being prescribed more opioids than needed, while two (3.5%) felt the amount was less than needed. Though not significant, participants who underwent major surgeries were more likely to report being prescribed more than needed (53.5%) compared with participants who underwent minor surgeries (35.7%; p = 0.47). Though not significant, participants with anxiety were less likely to report being prescribed more tablets than needed compared with participants without anxiety (44.4% vs. 57.1%; p = 0.38). This was also true of participants with depression compared with those without (37.5% vs. 58.3%; p = 0.17), and those with chronic pain compared with those without (33.3% vs. 60.0%; p = 0.10). Our current opioid prescription practice for postoperative pain management may exceed what patients need.

Respiratory depression in the intoxicated trauma patient: are opioids to blame?

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Shenk, Eleni; Barton, Cassie A; Mah, Nathan D; Ran, Ran; Hendrickson, Robert G; Watters, Jennifer

2016-02-01

Providing effective pain management to acutely intoxicated trauma patients represents a challenge of balancing appropriate pain management with the risk of potential respiratory depression from opioid administration. The objective of this study was to quantify the incidence of respiratory depression in trauma patients acutely intoxicated with ethanol who received opioids as compared with those who did not and identify potential risk factors for respiratory depression in this population. Retrospective medical record review was conducted for subjects identified via the trauma registry who were admitted as a trauma activation and had a detectable serum ethanol level upon admission. Risk factors and characteristics compared included demographics, Injury Severity Score, Glasgow Coma Score, serum ethanol level upon arrival, urine drug screen results, incidence of respiratory depression, and opioid and other sedative medication use. A total of 233 patients were included (78.5% male). Patients who received opioids were more likely to have a higher Injury Severity Score and initial pain score on admission as compared with those who did not receive opioids. Blood ethanol content was higher in patients who did not receive opioids (0.205 vs 0.237 mg/dL, P = .015). Patients who did not receive opioids were more likely to be intubated within 4 hours of admission (1.7% vs 12.1%, P = .02). Opioid administration was not associated with increased risk of respiratory depression (19.7% vs 22.4%, P = .606). Increased cumulative fentanyl dose was associated with increased risk of respiratory depression. Increased cumulative fentanyl dose, but not opioid administration alone, was found to be a risk factor for respiratory depression. Copyright © 2015 Elsevier Inc. All rights reserved.

Inhibition of GABAergic Neurotransmission by HIV-1 Tat and Opioid Treatment in the Striatum Involves μ-opioid Receptors

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Changqing Xu

2016-11-01

Full Text Available Due to combined antiretroviral therapy (cART, human immunodeficiency virus type 1 (HIV-1 is considered a chronic disease with high prevalence of mild forms of neurocognitive impairments, also referred to as HIV-associated neurocognitive disorders (HAND. Although opiate drug use can exacerbate HIV-1 Tat-induced neuronal damage, it remains unknown how and to what extent opioids interact with Tat on the GABAergic system. We conducted whole-cell recordings in mouse striatal slices and examined the effects of HIV-1 Tat in the presence and absence of morphine (1 μM and damgo (1 μM on GABAergic neurotransmission. Results indicated a decrease in the frequency and amplitude of spontaneous inhibitory postsynaptic currents (sIPSCs and miniature IPSCs (mIPSCs by Tat (5 – 50 nM in a concentration-dependent manner. The significant Tat-induced decrease in IPSCs was abolished when removing extracellular and/or intracellular calcium. Treatment with morphine or damgo alone significantly decreased the frequency, but not amplitude of IPSCs. Interestingly, morphine but not damgo indicated an additional downregulation of the mean frequency of mIPSCs in combination with Tat. Pretreatment with naloxone (1 μM and CTAP (1 μM prevented the Tat-induced decrease in sIPSCs frequency but only naloxone prevented the combined Tat and morphine effect on mIPSCs frequency. Results indicate a Tat- or opioid-induced decrease in GABAergic neurotransmission via µ-opioid receptors with combined Tat and morphine effects involving additional opioid receptor-related mechanisms. Exploring the interactions between Tat and opioids on the GABAergic system may help to guide future research on HAND in the context of opiate drug use.

Can we predict addiction to opioid analgesics? A possible tool to estimate the risk of opioid addiction in patients with pain.

Science.gov (United States)

Skala, Katrin; Reichl, Lukas; Ilias, Wilfried; Likar, Rudolf; Grogl-Aringer, Gabriele; Wallner, Christina; Schlaff, Golda; Herrmann, Peter; Lesch, Otto; Walter, Henriette

2013-01-01

The use of opioid analgesics in the treatment of chronic pain conditions has long been controversial. They have been reported to be relatively safe when prescribed with caution, but a brief and valid instrument to estimate a person's risk of addiction is still missing. The aim of this study was to investigate a self-rating questionnaire allowing an estimation of a person's risk of addiction to opioid analgesics. Retrospective review. Four Austrian hospitals. Seven hundred forty-one patients were interviewed. Of these, 634 patients were affected with chronic pain while 107 patients had a history of opioid addiction. Patients were interviewed about alcohol and nicotine consumption and family history of psychiatric disorders. Attitudes towards medication and the origin of pain were examined. We asked patients with an opioid addiction and patients suffering from chronic pain to complete a short questionnaire intended to help screen for addiction potential. Compared to the patients suffering from chronic pain, patients with an opioid addiction significantly more often had alcohol- and nicotine-related pathologies and psychiatric comorbidity. A family history of mental illness and developmental problems were significantly more frequent in this group. Compared to those not addicted, those with an opioid addiction had significantly higher expectations concerning the potential of medication to change one's mental state; they thought that psychological  factors might contribute to the pain they feel. The main limitation of this study is the use of a self-rating instrument which reduces objectivity and introduces the possibility of misreporting. Also, the 2 groups differ in number and are not homogenous. We found differences in questionnaire responses between patients with an opioid addiction and patients suffering from chronic pain to be dependent upon the prevalence of current or former addiction, psychiatric history, attitudes towards medication, and ideas about the

Is mechanism and symptom-based analgesia an answer to opioid-Induced hyperalgesia?

Directory of Open Access Journals (Sweden)

Mayank Gupta

2015-01-01

Full Text Available "Cancer Pain" and "Pain in cancer patient" are not synonymous. Opioid-induced Hyperalgesia (OIH is a paradoxical state of nociceptive sensitization caused by exposure to opioids. Neuropathic pain is only partially responsive to opioids; injudicious increase in dose of opioids in neuropathic pain may not only result in inadequate pain relief but also OIH. Majority of literature on OIH is in non-cancer pain with systemic use of opioids. We describe the development and successful treatment of OIH in a 55-year-old male patient with Small cell Carcinoma Lung. Opioid tapering, rotation, systemic desensitization helps in combatting OIH. The use of anti-neuropathic adjuvant analgesics helps not only in preventing and treating OIH but also in understanding putative mechanisms underlying neuropathic pain and OIH.

Exercise induced asthma and endogenous opioids.

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Gaillard, R C; Bachman, M; Rochat, T; Egger, D; de Haller, R; Junod, A F

1986-01-01

Concentrations of endogenous opioid peptides in the plasma are increased during exercise and these substances have been implicated in the pathogenesis of asthma induced by chloropropramide and alcohol in diabetic patients. This work was undertaken to determine whether exercise induced asthma might be mediated by endogenous opioids. Plasma beta endorphin, met-enkephalin, and adrenocorticotrophic hormone (ACTH) concentrations were measured in five asthmatic patients and five normal volunteers breathing cold air during exercise. In four of the patients the effect of an infusion of naloxone on FEV1 was also measured during exercise induced asthma. Exercise produced acute bronchoconstriction in all asthmatics, characterised by a fall in FEV1; whereas no change occurred in normal subjects. There was no difference in plasma met-enkephalin, beta endorphin, and ACTH concentration between the two groups. Infusion of naloxone neither prevented nor worsened exercise induced asthma. These data suggest that endogenous opioids probably do not play a part in the development of exercise induced asthma. PMID:2944240

Prescription opioid misuse in the United States and the United Kingdom: cautionary lessons.

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Weisberg, Daniel F; Becker, William C; Fiellin, David A; Stannard, Cathy

2014-11-01

In the United States, opioid analgesics have increasingly been prescribed in the treatment of chronic pain, and this trend has accompanied increasing rates of misuse and overdose. Lawmakers have responded with myriad policies to curb the growing epidemic of opioid misuse, and a global alarm has been sounded among countries wishing to avoid this path. In the United Kingdom, a similar trend of increasing opioid consumption, albeit at lower levels, has been observed without an increase in reported misuse or drug-related deaths. The comparison between these two countries in opioid prescribing and opioid overdose mortality underscores important features of prescribing, culture, and health systems that may be permissive or protective in the development of a public health crisis. As access to opioid medications increases around the world, it becomes vitally important to understand the forces impacting opioid use and misuse. Trends in benzodiazepine and methadone use in the UK as well as structural elements of the National Health Service may serve to buffer opioid-related harms in the face of increasing prescriptions. In addition, the availability and price of heroin, as well as the ease of access to opioid agonist treatment in the UK may limit the growth of the illicit market for prescription opioids. The comparison between the US and the UK in opioid consumption and overdose rates should serve as a call to action for UK physicians and policymakers. Basic, proactive steps in the form of surveillance - of overdoses, marketing practices, prescribers, and patients - and education programs may help avert a public health crisis as opioid prescriptions increase. Copyright © 2014 Elsevier B.V. All rights reserved.

Changing Trends in Opioid Use Among Patients With Rheumatoid Arthritis in the United States.

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Curtis, Jeffrey R; Xie, Fenglong; Smith, Christian; Saag, Kenneth G; Chen, Lang; Beukelman, Timothy; Mannion, Melissa; Yun, Huifeng; Kertesz, Stefan

2017-09-01

Opioid prescribing recently has come under intense scrutiny. However, longitudinal patterns of prescription opioid receipt in a population-based cohort of patients with chronic pain, such as those with rheumatoid arthritis (RA), have not been well characterized. The aim of this study was to examine both trends over time and variability in individual physician prescribing of short-term and long-term use of opioids. We identified a cohort of RA patients based on 2006-2014 Medicare data and evaluated longitudinal time trends in "regular" use of opioids. A separate analysis conducted in 2014 assessed rheumatologist-specific variability in regular use of opioid prescriptions in patients with RA. We identified 97,859 RA patients meeting the eligibility criteria. The mean age of the patients was 67 years, 80% were female, 82% were white, and 12% were African American. The most commonly used opioids were those that combined acetaminophen with hydrocodone or propoxyphene. Regular opioid prescribing increased slowly but peaked in 2010 before propoxyphene was withdrawn from the market. Following the withdrawal of propoxyphene, receipt of hydrocodone and tramadol increased commensurately, and overall opioid use declined only slightly. Factors associated with regular use of opioids included younger age, female sex, African American race, back pain, fibromyalgia, anxiety, and depression. Variability between US rheumatologists (n = 4,024) in prescribing the regular use of opioids for their RA patients was high; in the average rheumatologist's practice, 40% of RA patients used prescription opioids regularly. In almost half of the patients, at least some opioid prescriptions were written by a rheumatologist, and 14% received opioids that were co-prescribed concurrently by more than 1 physician. In the US, opioid use in older patients with RA peaked in 2010 and is now declining slightly. Withdrawal of propoxyphene from the US market in 2010 had minimal effect on overall opioid

Opioids and Chronic Pain | NIH MedlinePlus the Magazine

Science.gov (United States)

... Long-term daily use of opioids leads to physical dependence, which is not to be confused with addiction ... be screened and closely monitored. When people have physical dependence and the opioid use is stopped, withdrawal symptoms ...

Molecular pharmacology of 4-substituted glutamic acid analogues at ionotropic and metabotropic excitatory amino acid receptors

DEFF Research Database (Denmark)

Bräuner-Osborne, Hans; Nielsen, B; Stensbøl, T B

1997-01-01

(subtypes 1alpha and 2), respectively, whereas (S)-4-methyleneglutamic acid showed high but rather non-selective affinity for the (RS)-2-amino-3-(3-hydroxy-5-methylisoxazol-4-yl)propionic acid (AMPA), kainic acid, NMDA and mGlu receptors (subtypes 1alpha and 2). Although none of the compounds were specific......The pharmacology of (2S,4R)-4-methylglutamic acid, (2S,4S)-4-methylglutamic acid and (S)- and (R)-4-methyleneglutamic acids (obtained in high chemical and enantiomeric purity from racemic 4-methyleneglutamic acid by chiral HPLC using a Crownpak CR(+) column), was examined in binding experiments...... using rat brain ionotropic glutamate receptors, and in functional assays using cloned metabotropic glutamate (mGlu) receptors. As a notable result of these studies, (2S,4R)-4-methylglutamic acid and (2S,4S)-4-methylglutamic acid were shown to be selective for kainic acid receptors and mGlu receptors...

Haloperidol Disrupts Opioid-Antinociceptive Tolerance and Physical Dependence

Science.gov (United States)

Yang, Cheng; Chen, Yan; Tang, Lei

2011-01-01

Previous studies from our laboratory and others have implicated a critical role of Ca2+/calmodulin-dependent protein kinase II (CaMKII) in opioid tolerance and dependence. Translational research targeting the CaMKII pathway is challenging, if not impossible, because of a lack of selective inhibitors. We discovered in a preliminary study that haloperidol, a butyrophenone antipsychotic drug, inhibited CaMKII, which led us to hypothesize that haloperidol can attenuate opioid tolerance and dependence by inhibiting CaMKII. The hypothesis was tested in two rodent models of opioid tolerance and dependence. Pretreatment with haloperidol (0.2–1.0 mg/kg i.p.) prevented the development of morphine tolerance and dependence in a dose-dependent manner. Short-term treatment with haloperidol (0.06–0.60 mg/kg i.p.) dose-dependently reversed the established morphine-antinociceptive tolerance and physical dependence. Correlating with behavioral effects, pretreatment or short-term treatment with haloperidol dose-dependently inhibited morphine-induced up-regulation of supraspinal and spinal CaMKIIα activity. Moreover, haloperidol given orally was also effective in attenuating morphine-induced CaMKIIα activity, antinociceptive tolerance, and physical dependence. Taken together, these data suggest that haloperidol attenuates opioid tolerance and dependence by suppressing CaMKII activity. Because haloperidol is a clinically used drug that can be taken orally, we propose that the drug may be of use in attenuating opioid tolerance and dependence. PMID:21436292

"I was a little surprised": Qualitative Insights from Patients Enrolled in a 12-Month Trial Comparing Opioids to Non-Opioid Medications for Chronic Musculoskeletal Pain.

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Marianne S Matthias; Donaldson, Melvin T; Jensen, Agnes C; Krebs, Erin E

2018-04-28

Chronic musculoskeletal pain is a major public health problem. Although opioid prescribing for chronic pain has increased dramatically since the 1990s, this practice has come under scrutiny because of increases in opioid-related harms and lack of evidence for long-term effectiveness. The Strategies for Prescribing Analgesics Comparative Effectiveness (SPACE) trial was a pragmatic 12-month randomized trial comparing benefits and harms of opioid versus non-opioid medications for chronic musculoskeletal pain. The current qualitative study was designed to better understand trial results by exploring patients' experiences, including perceptions of medications, experiences with the intervention, and whether expectations were met. Thirty-four participants who were purposefully sampled based on treatment group and intervention response participated in semi-structured interviews. The constant comparison method guided analysis. Results revealed that participants often held strong beliefs about opioid medications, which sometimes changed during the trial as they gained experience with medications; participants described a wide variety of experiences with treatment effectiveness, regardless of study group or their response to the intervention; and participants highly valued the personalized pain care model used in SPACE. SPACE trial results indicated no advantage for opioid over non-opioid medications. Qualitative findings suggest that, for patients in both treatment groups, pre-existing expectations of medications and of anticipated improvement in pain shaped experiences with and responses to medications. In addition, the personalized pain care model was described as contributing to positive outcomes in both groups. Copyright © 2018. Published by Elsevier Inc.

μ-opioid modulation of HIV-1 coreceptor expressionand HIV-1 replication

International Nuclear Information System (INIS)

Steele, Amber D.; Henderson, Earl E.; Rogers, Thomas J.

2003-01-01

A substantial proportion of HIV-1-infected individuals are intravenous drug users (IVDUs) who abuse opiates. Opioids induce a number of immunomodulatory effects that may directly influence HIV-1 disease progression. In the present report, we have investigated the effect of opioids on the expression of the major HIV-1 coreceptors CXCR4 and CCR5. For these studies we have focused on opiates which are ligands for the μ-opioid receptor. Our results show that DAMGO, a selective μ-opioid agonist, increases CXCR4 and CCR5 expression in both CD3 + lymphoblasts and CD14 + monocytes three- to fivefold. Furthermore, DAMGO-induced elevation of HIV-1 coreceptor expression translates into enhanced replication of both X4 and R5 viral strains of HIV-1. We have confirmed the role of the μ-opioid receptor based on the ability of a μ-opioid receptor-selective antagonist to block the effects of DAMGO. We have also found that morphine enhances CXCR4 and CCR5 expression and subsequently increases both X4 and R5 HIV-1 infection. We suggest that the capacity of μ-opioids to increase HIV-1 coreceptor expression and replication may promote viral binding, trafficking of HIV-1-infected cells, and enhanced disease progression

Review of Opioid Pharmacogenetics and Considerations for Pain Management.

Science.gov (United States)

Owusu Obeng, Aniwaa; Hamadeh, Issam; Smith, Michael

2017-09-01

Opioid analgesics are the standards of care for the treatment of moderate to severe nociceptive pain, particularly in the setting of cancer and surgery. Their analgesic properties mainly emanate from stimulation of the μ receptors, which are encoded by the OPRM1 gene. Hepatic metabolism represents the major route of elimination, which, for some opioids, namely codeine and tramadol, is necessary for their bioactivation into more potent analgesics. The highly polymorphic nature of the genes coding for phase I and phase II enzymes (pharmacokinetics genes) that are involved in the metabolism and bioactivation of opioids suggests a potential interindividual variation in their disposition and, most likely, response. In fact, such an association has been substantiated in several pharmacokinetic studies described in this review, in which drug exposure and/or metabolism differed significantly based on the presence of polymorphisms in these pharmacokinetics genes. Furthermore, in some studies, the observed variability in drug exposure translated into differences in the incidence of opioid-related adverse effects, particularly nausea, vomiting, constipation, and respiratory depression. Although the influence of polymorphisms in pharmacokinetics genes, as well as pharmacodynamics genes (OPRM1 and COMT) on response to opioids has been a subject of intense research, the results have been somehow conflicting, with some evidence insinuating for a potential role for OPRM1. The Clinical Pharmacogenetics Implementation Consortium guidelines provide CYP2D6-guided therapeutic recommendations to individualize treatment with tramadol and codeine. However, implementation guidelines for other opioids, which are more commonly used in real-world settings for pain management, are currently lacking. Hence, further studies are warranted to bridge this gap in our knowledge base and ultimately ascertain the role of pharmacogenetic markers as predictors of response to opioid analgesics. © 2017

Intraoperative ketamine reduces immediate postoperative opioid consumption after spinal fusion surgery in chronic pain patients with opioid dependency: a randomized, blinded trial.

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Nielsen, Rikke Vibeke; Fomsgaard, Jonna Storm; Siegel, Hanna; Martusevicius, Robertas; Nikolajsen, Lone; Dahl, Jørgen Berg; Mathiesen, Ole

2017-03-01

Perioperative handling of surgical patients with opioid dependency represents an important clinical problem. Animal studies suggest that ketamine attenuates central sensitization and hyperalgesia and thereby reduces postoperative opioid tolerance. We hypothesized that intraoperative ketamine would reduce immediate postoperative opioid consumption compared with placebo in chronic pain patients with opioid dependency undergoing lumbar spinal fusion surgery. Primary outcome was morphine consumption 0 to 24 hours postoperatively. Secondary outcomes were acute pain at rest and during mobilization 2 to 24 hours postoperatively (visual analogue scale), adverse events, and persistent pain 6 months postoperatively. One hundred fifty patients were randomly assigned to intraoperative S-ketamine bolus 0.5 mg/kg and infusion 0.25 mg·kg·h or placebo. Postoperatively, patients received their usual opioids, paracetamol and IV patient-controlled analgesia with morphine. In the final analyses, 147 patients were included. Patient-controlled analgesia IV morphine consumption 0 to 24 hours postoperatively was significantly reduced in the ketamine group compared with the placebo group: 79 (47) vs 121 (53) mg IV, mean difference 42 mg (95% confidence interval -59 to -25), P ketamine group 6 and 24 hours postoperatively. There were no significant differences regarding acute pain, nausea, vomiting, hallucinations, or nightmares. Back pain at 6 months postoperatively compared with preoperative pain was significantly more improved in the ketamine group compared with the placebo group, P = 0.005. In conclusion, intraoperative ketamine significantly reduced morphine consumption 0 to 24 hours after lumbar fusion surgery in opioid-dependent patients. The trend regarding less persistent pain 6 months postoperatively needs further investigation.

Dynamical responses to external stimuli for both cases of excitatory and inhibitory synchronization in a complex neuronal network.

Science.gov (United States)

Kim, Sang-Yoon; Lim, Woochang

2017-10-01

For studying how dynamical responses to external stimuli depend on the synaptic-coupling type, we consider two types of excitatory and inhibitory synchronization (i.e., synchronization via synaptic excitation and inhibition) in complex small-world networks of excitatory regular spiking (RS) pyramidal neurons and inhibitory fast spiking (FS) interneurons. For both cases of excitatory and inhibitory synchronization, effects of synaptic couplings on dynamical responses to external time-periodic stimuli S ( t ) (applied to a fraction of neurons) are investigated by varying the driving amplitude A of S ( t ). Stimulated neurons are phase-locked to external stimuli for both cases of excitatory and inhibitory couplings. On the other hand, the stimulation effect on non-stimulated neurons depends on the type of synaptic coupling. The external stimulus S ( t ) makes a constructive effect on excitatory non-stimulated RS neurons (i.e., it causes external phase lockings in the non-stimulated sub-population), while S ( t ) makes a destructive effect on inhibitory non-stimulated FS interneurons (i.e., it breaks up original inhibitory synchronization in the non-stimulated sub-population). As results of these different effects of S ( t ), the type and degree of dynamical response (e.g., synchronization enhancement or suppression), characterized by the dynamical response factor [Formula: see text] (given by the ratio of synchronization degree in the presence and absence of stimulus), are found to vary in a distinctly different way, depending on the synaptic-coupling type. Furthermore, we also measure the matching degree between the dynamics of the two sub-populations of stimulated and non-stimulated neurons in terms of a "cross-correlation" measure [Formula: see text]. With increasing A , based on [Formula: see text], we discuss the cross-correlations between the two sub-populations, affecting the dynamical responses to S ( t ).

Opioid Prescribing PSA (:60)

Centers for Disease Control (CDC) Podcasts

This 60 second public service announcement is based on the July 2017 CDC Vital Signs report. Higher opioid prescribing puts patients at risk for addiction and overdose. Learn what can be done about this serious problem.

Analgesic synergy between opioid and α2 -adrenoceptors.

Science.gov (United States)

Chabot-Doré, A-J; Schuster, D J; Stone, L S; Wilcox, G L

2015-01-01

Opioid and α2 -adrenoceptor agonists are potent analgesic drugs and their analgesic effects can synergize when co-administered. These supra-additive interactions are potentially beneficial clinically; by increasing efficacy and/or reducing the total drug required to produce sufficient pain relief, undesired side effects can be minimized. However, combination therapies of opioids and α2 -adrenoceptor agonists remain underutilized clinically, in spite of a large body of preclinical evidence describing their synergistic interaction. One possible obstacle to the translation of preclinical findings to clinical applications is a lack of understanding of the mechanisms underlying the synergistic interactions between these two drug classes. In this review, we provide a detailed overview of the interactions between different opioid and α2 -adrenoceptor agonist combinations in preclinical studies. These studies have identified the spinal cord as an important site of action of synergistic interactions, provided insights into which receptors mediate these interactions and explored downstream signalling events enabling synergy. It is now well documented that the activation of both μ and δ opioid receptors can produce synergy with α2 -adrenoceptor agonists and that α2 -adrenoceptor agonists can mediate synergy through either the α2A or the α2C adrenoceptor subtypes. Current hypotheses surrounding the cellular mechanisms mediating opioid-adrenoceptor synergy, including PKC signalling and receptor oligomerization, and the evidence supporting them are presented. Finally, the implications of these findings for clinical applications and drug discovery are discussed. This article is part of a themed section on Opioids: New Pathways to Functional Selectivity. To view the other articles in this section visit http://dx.doi.org/10.1111/bph.2015.172.issue-2. © 2014 The British Pharmacological Society.

Endogenous opioid peptide-mediated neurotransmission in central and pericentral nuclei of the inferior colliculus recruits μ1-opioid receptor to modulate post-ictal antinociception.

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Felippotti, Tatiana Tocchini; de Freitas, Renato Leonardo; Coimbra, Norberto Cysne

2012-02-01

The aim of the present work was to investigate the involvement of the μ1-endogenous opioid peptide receptor-mediated system in post-ictal antinociception. Antinociceptive responses were determined by the tail-flick test after pre-treatment with the selective μ1-opioid receptor antagonist naloxonazine, peripherally or centrally administered at different doses. Peripheral subchronic (24 h) pre-treatment with naloxonazine antagonised the antinociception elicited by tonic-clonic seizures. Acute (10 min) pre-treatment, however, did not have the same effect. In addition, microinjections of naloxonazine into the central, dorsal cortical and external cortical nuclei of the inferior colliculus antagonised tonic-clonic seizure-induced antinociception. Neither acute (10-min) peripheral pre-treatment with naloxonazine nor subchronic intramesencephalic blockade of μ1-opioid receptors resulted in consistent statistically significant differences in the severity of tonic-clonic seizures shown by Racine's index (1972), although the intracollicular specific antagonism of μ1-opioid receptor decreased the duration of seizures. μ1-Opioid receptors and the inferior colliculus have been implicated in several endogenous opioid peptide-mediated responses such as antinociception and convulsion. The present findings suggest the involvement of μ1-opiate receptors of central and pericentral nuclei of the inferior colliculus in the modulation of tonic-clonic seizures and in the organisation of post-ictal antinociception. Copyright © 2011 Elsevier Ltd. All rights reserved.

Heterogeneity of Opioid Binding Sites in Guinea Pig Spinal Cord

Science.gov (United States)

1984-11-30

MEDICAL CENTER WILFORD HALL AIR FORCE MEDICAL CENTER Title of Thesis: "Heterogeneity of Opioid Binding Sites in Guinea Pig Spinal Cord" Name of...that the use of any copyrighted material in the dissertation manuscript entitled: "Heterogeneity of Opioid Binding Sites in Guinea Pig Spinal Cord...University of the Health Sciences 11 Abstract Title of Thesis: Heterogenity of Opioid Binding Sites In Guinea Pig Spinal Cord Gary Dean Zarr MAJ/ANC

Successful Treatment of Opioid-Refractory Cancer Pain with Short-Course, Low-Dose Ketamine.

Science.gov (United States)

Waldfogel, Julie M; Nesbit, Suzanne; Cohen, Steven P; Dy, Sydney M

2016-12-01

Opioids remain the mainstay of treatment for severe cancer pain, but up to 20% of patients have persistent or refractory pain despite rapid and aggressive opioid titration, or develop refractory pain after long-term opioid use. In these scenarios, alternative agents and mechanisms for analgesia should be considered. This case report describes a 28-year-old man with metastatic pancreatic neuroendocrine cancer with severe, intractable pain despite high-dose opioids including methadone and a hydromorphone patient-controlled analgesia (PCA). After treatment with short-course, low-dose ketamine, his opioid requirements decreased by 99% and pain ratings by 50%, with the majority of this decrease occurring in the first 48 hours. As this patient's pain and opioid regimen escalated, he likely experienced some component of central sensitization and hyperalgesia. Administration of ketamine reduced opioid consumption by 99% and potentially "reset" neuronal hyperexcitability and reduced pain signaling, allowing for improved pain control.

Preparation, characterization and biological evaluation of fac(M(CO)3)+ labeled amino carboxy ligands

International Nuclear Information System (INIS)

Baishya, Rinku; Halder, K.K.; Debnath, M.C.

2010-01-01

Full text: The objective of this study is to radiolabel various amino carboxy based chelating ligands with fac(M(CO) 3 )+ core, their physicochemical and biological characterization so that they can be used as bifunctional chelators and could be incorporated into biomolecules. Introduction: Amino acids as a class attract considerable physiological interest because of their participation in many vital processes associated with the living system. Some amino acids express in some particular organ like glutamic acid acts as excitatory neurotransmitter in mammalian brain. Histidine, methionine, tryptophan express in the tumor cell. Amino acids also play an important role for development of a new series of chelate complexes of 99m Tc that can direct the biodistribution of the radiotracer for purposes in diagnostic nuclear medicine. Various 99m Tc-amino acid chelates based on (Tc(V)O) 3 + core were reported from this laboratory some of which exhibited high renal specificity in animals. The structural requirements favouring this biological behaviour could be the oxotechnetium glycine sequence (TcO-NH-CH 2 -COOH) resembling the -CO-glycine sequence of hippurate. In recent years with the development of organometallic chemistry of technetium and rhenium for biological application intensive efforts have been executed on designing of the bifunctional chelator for effective coordination to (M(CO) 3 )+ core. The suitability and stability of the metal carbonyl core has given rise to a new platform for the preparation of the metal complexes of biologically active peptide in macroscopic quantity using the solid phase synthetic approach. Materials and Methods: We chelated different amino carboxy based ligands with ( 99m Tc(CO) 3 )+ and (Re(CO) 3 )+ core. The choice of amino acid was made by taking representative members from various groupings such as mono amino mono carboxylate, mono amino poly carboxylate, poly amino mono carboxylate and sulfur containing amino carboxylates. The

Variability in prescription opioid intake and reinforcement amongst 129 substrains.

Science.gov (United States)

Jimenez, S M; Healy, A F; Coelho, M A; Brown, C N; Kippin, T E; Szumlinski, K K

2017-09-01

Opioid abuse in the United States has reached epidemic proportions, with treatment admissions and deaths associated with prescription opioid abuse quadrupling over the past 10 years. Although genetics are theorized to contribute substantially to inter-individual variability in the development, severity and treatment outcomes of opioid abuse/addiction, little direct preclinical study has focused on the behavioral genetics of prescription opioid reinforcement and drug-taking. Herein, we employed different 129 substrains of mice currently available from The Jackson Laboratory (129S1/SvlmJ, 129X1/SvJ, 129S4/SvJaeJ and 129P3/J) as a model system of genetic variation and assayed mice for oral opioid intake and reinforcement, as well as behavioral and somatic signs of dependence. All substrains exhibited a dose-dependent increase in oral oxycodone and heroin preference and intake under limited-access procedures and all, but 129S1/SvlmJ mice, exhibited oxycodone reinforcement. Relative to the other substrains, 129P3/J mice exhibited higher heroin and oxycodone intake. While 129X1/SvJ exhibited the highest anxiety-like behavior during natural opioid withdrawal, somatic and behavior signs of precipitated withdrawal were most robust in 129P3/J mice. These results demonstrate the feasibility and relative sensitivity of our oral opioid self-administration procedures for detecting substrain differences in drug reinforcement/intake among 129 mice, of relevance to the identification of genetic variants contributing to high vs. low oxycodone reinforcement and intake. © 2017 John Wiley & Sons Ltd and International Behavioural and Neural Genetics Society.

Quality Improvement Initiative to Decrease Variability of Emergency Physician Opioid Analgesic Prescribing

Directory of Open Access Journals (Sweden)

John H. Burton

2016-05-01

Full Text Available Introduction: Addressing pain is a crucial aspect of emergency medicine. Prescription opioids are commonly prescribed for moderate to severe pain in the emergency department (ED; unfortunately, prescribing practices are variable. High variability of opioid prescribing decisions suggests a lack of consensus and an opportunity to improve care. This quality improvement (QI initiative aimed to reduce variability in ED opioid analgesic prescribing. Methods: We evaluated the impact of a three-part QI initiative on ED opioid prescribing by physicians at seven sites. Stage 1: Retrospective baseline period (nine months. Stage 2: Physicians were informed that opioid prescribing information would be prospectively collected and feedback on their prescribing and that of the group would be shared at the end of the stage (three months. Stage 3: After physicians received their individual opioid prescribing data with blinded comparison to the group means (from Stage 2 they were informed that individual prescribing data would be unblinded and shared with the group after three months. The primary outcome was variability of the standard error of the mean and standard deviation of the opioid prescribing rate (defined as number of patients discharged with an opioid divided by total number of discharges for each provider. Secondary observations included mean quantity of pills per opioid prescription, and overall frequency of opioid prescribing. Results: The study group included 47 physicians with 149,884 ED patient encounters. The variability in prescribing decreased through each stage of the initiative as represented by the distributions for the opioid prescribing rate: Stage 1 mean 20%; Stage 2 mean 13% (46% reduction, p<0.01, and Stage 3 mean 8% (60% reduction, p<0.01. The mean quantity of pills prescribed per prescription was 16 pills in Stage 1, 14 pills in Stage 2 (18% reduction, p<0.01, and 13 pills in Stage 3 (18% reduction, p<0.01. The group mean

The opioid crisis: past, present and future policy climate in Ontario, Canada.

Science.gov (United States)

Morin, Kristen A; Eibl, Joseph K; Franklyn, Alexandra M; Marsh, David C

2017-11-02

Addressing opioid use disorder has become a priority in Ontario, Canada, because of its high economic, social and health burden. There continues to be stigma and criticism relating to opioid use disorder and treatment options. The result has been unsystematic, partial, reactive policies and programs developed based on divergent points of view. The aim of this manuscript is to describe how past and present understandings, narratives, ideologies and discourse of opioid use, have impacted policies over the course of the growing opioid crisis. Assessing the impact of policy is complex. It involves consideration of conceptual issues of what impacts policy change. In this manuscript we argue that the development of polices and initiatives regarding opioids, opioid use disorder and opioid agonist treatment in the last decade, have been more strongly associated with the evolution of ideas, narratives and discourses rather than research relating to opioids. We formulate our argument using a framework by Sumner, Crichton, Theobald, Zulu, and Parkhurs. We use examples from the Canadian context to outline our argument such as: the anti- drug legislation from the Canadian Federal Conservative government in 2007; the removal of OxyContin™ from the drug formulary in 2012; the rapid expansion of opioid agonist treatment beginning in the early 2000s, the unilateral decision made regarding fee cuts for physicians providing opioid agonist treatment in 2015; and the most recent implementation of a narcotics monitoring system, which are all closely linked with the shifts in public opinion and discourse at the time of which these policies and programs are implemented. We conclude with recommendations to consider a multifactorial response using evidence and stakeholder engagement to address the opioid crisis, rather than a reactive policy approach. We suggest that researchers have an important role in shaping future policy by reframing ideas through knowledge translation, formation of

Detection of amino acid neurotransmitters by surface enhanced Raman scattering and hollow core photonic crystal fiber

Science.gov (United States)

Tiwari, Vidhu S.; Khetani, Altaf; Monfared, Ali Momenpour T.; Smith, Brett; Anis, Hanan; Trudeau, Vance L.

2012-03-01

The present work explores the feasibility of using surface enhanced Raman scattering (SERS) for detecting the neurotransmitters such as glutamate (GLU) and gamma-amino butyric acid (GABA). These amino acid neurotransmitters that respectively mediate fast excitatory and inhibitory neurotransmission in the brain, are important for neuroendocrine control, and upsets in their synthesis are also linked to epilepsy. Our SERS-based detection scheme enabled the detection of low amounts of GLU (10-7 M) and GABA (10-4 M). It may complement existing techniques for characterizing such kinds of neurotransmitters that include high-performance liquid chromatography (HPLC) or mass spectrography (MS). This is mainly because SERS has other advantages such as ease of sample preparation, molecular specificity and sensitivity, thus making it potentially applicable to characterization of experimental brain extracts or clinical diagnostic samples of cerebrospinal fluid and saliva. Using hollow core photonic crystal fiber (HC-PCF) further enhanced the Raman signal relative to that in a standard cuvette providing sensitive detection of GLU and GABA in micro-litre volume of aqueous solutions.

Barriers to access to opioid medicines for patients with opioid dependence: a review of legislation and regulations in eleven central and eastern European countries.

Science.gov (United States)

Vranken, Marjolein J M; Mantel-Teeuwisse, Aukje K; Jünger, Saskia; Radbruch, Lukas; Scholten, Willem; Lisman, John A; Subataite, Marija; Schutjens, Marie-Hélène D B

2017-06-01

Barriers linked to drug control systems are considered to contribute to inequitable access to controlled medicines, leaving millions of people in pain and suffering. Most studies focus on access to opioids for the treatment of severe (cancer) pain. This study aims to identify specific access barriers for patients with opioid dependence in legislation and regulations of 11 central and eastern European countries. This study builds on a previous analysis of legislation and regulations as part of the EU 7th Framework Access To Opioid Medication in Europe (ATOME) project. An in-depth analysis was undertaken to determine specific barriers for patients with opioid dependence in need of opioid analgesics or opioid agonist therapy (OAT). For each country, the number and nature of specific potential barriers for these patients were assessed according to eight categories: prescribing; dispensing; manufacturing; usage; trade and distribution; affordability; penalties; and other. An additional keyword search was conducted to minimize the omission of barriers. Barriers in an additional category, language, were recorded qualitatively. Countries included Bulgaria, Cyprus, Estonia, Greece, Hungary, Latvia, Lithuania, Serbia, Slovakia, Slovenia and Turkey. Ten of the 11 countries (all except Estonia) showed specific potential barriers in their legislation and regulations. The total number of barriers varied from two (Slovenia) to 46 (Lithuania); the number of categories varied from one (Slovenia) to five (Lithuania). Most specific potential barriers were shown in the categories 'prescribing', 'usage' and 'other'. The total number in a single category varied from one to 18 (Lithuania, prescribing). Individual differences between countries in the same specific potential barrier were shown; for example, variation in minimum age criteria for admission to OAT ranging from 15 (Lithuania, in special cases) to 20 years (Greece). All countries had stigmatizing language in their legislation

Postoperative opioid analgesia: time for a reconsideration?

DEFF Research Database (Denmark)

Kehlet, H; Rung, G W; Callesen, T

1996-01-01

Postoperative pain relief has improved in recent years with the development of new analgesics, additional routes of administration and the appearance of the hypothesis of preemptive as well as balanced analgesia (Kehlet H; Postoperative pain relief-what is the issue? Br J Anaesth 1994;72:375-8). ......Postoperative pain relief has improved in recent years with the development of new analgesics, additional routes of administration and the appearance of the hypothesis of preemptive as well as balanced analgesia (Kehlet H; Postoperative pain relief-what is the issue? Br J Anaesth 1994......;72:375-8). Many initial improvements simply involved the administration of opioid analgesics in new ways, such as continuous or on demand intravenous (i.v.) or epidural infusion. These methods allow lower total opioid dosages, provide a more stable concentration of opioid at the receptor and correspondingly...

Trait Mindfulness and Progression to Injection Use in Youth With Opioid Addiction.

Science.gov (United States)

Wilson, J Deanna; Vo, Hoa; Matson, Pamela; Adger, Hoover; Barnett, Gabriela; Fishman, Marc

2017-09-19

Many youth initiate opioid misuse with prescription opioids and transition over time to more severe substance-using behaviors, including injection. Trait mindfulness is a potentially protective factor. This is a cross-sectional study characterizing a sample of opioid-using youth by level of mindfulness and examines the potential effect modification of emotion regulation on the relationship between mindfulness and progression to injection opioid use. A convenience sample of 112 youth (ages 14-24) was recruited during an episode of inpatient detoxification and residential treatment for opioid use disorders. We examined emotion regulation (Difficulties in Emotion Regulation Scale), mindfulness (Child Acceptance and Mindfulness Measure), and opioid use. We completed multivariable regressions stratified by degree of emotion regulation looking at relationship of mindfulness on time to injection use from age of first prescription opioid. Youth had difficulties in emotion regulation (m = 104.2; SD = 2.41) and low mindfulness (m = 19.1;SD = 0.59). While we found overall that mindfulness was associated with time to progression to injection opioid use, there was significant effect modification. Among youth with high levels of difficulty in emotion regulation, those with high mindfulness trait had quicker progressions to injection (-1.31 years; p =.003). In contrast, youth with normal emotion regulation and high mindfulness trait had a slower progression to injection (1.67 years; p =.041). Conclusion/Importance: Our study showed a majority of youth presenting with opioid use disorders have impairments in emotion regulation and deficits in trait mindfulness. The relationship between mindfulness and opioid use is impacted by emotion regulation capacity. More research is needed to understand the various facets of mindfulness and how they interact with emotion regulation in youth.

Emergent spatial patterns of excitatory and inhibitory synaptic strengths drive somatotopic representational discontinuities and their plasticity in a computational model of primary sensory cortical area 3b

Directory of Open Access Journals (Sweden)

Kamil A. Grajski

2016-07-01

Full Text Available Mechanisms underlying the emergence and plasticity of representational discontinuities in the mammalian primary somatosensory cortical representation of the hand are investigated in a computational model. The model consists of an input lattice organized as a three-digit hand forward-connected to a lattice of cortical columns each of which contains a paired excitatory and inhibitory cell. Excitatory and inhibitory synaptic plasticity of feedforward and lateral connection weights is implemented as a simple covariance rule and competitive normalization. Receptive field properties are computed independently for excitatory and inhibitory cells and compared within and across columns. Within digit representational zones intracolumnar excitatory and inhibitory receptive field extents are concentric, single-digit, small, and unimodal. Exclusively in representational boundary-adjacent zones, intracolumnar excitatory and inhibitory receptive field properties diverge: excitatory cell receptive fields are single-digit, small, and unimodal; and the paired inhibitory cell receptive fields are bimodal, double-digit, and large. In simulated syndactyly (webbed fingers, boundary-adjacent intracolumnar receptive field properties reorganize to within-representation type; divergent properties are reacquired following syndactyly release. This study generates testable hypotheses for assessment of cortical laminar-dependent receptive field properties and plasticity within and between cortical representational zones. For computational studies, present results suggest that concurrent excitatory and inhibitory plasticity may underlie novel emergent properties.

Opioid Overdoses Treated in Emergency Departments PSA (:60)

Centers for Disease Control (CDC) Podcasts

2018-03-06

This 60 second public service announcement is based on the March 2018 CDC Vital Signs report. Opioid overdoses continue to increase in the United States. Learn what can be done to help prevent opioid overdose and death.  Created: 3/6/2018 by Centers for Disease Control and Prevention (CDC).   Date Released: 3/6/2018.

Inhibitory neurons modulate spontaneous signaling in cultured cortical neurons: density-dependent regulation of excitatory neuronal signaling

International Nuclear Information System (INIS)

Serra, Michael; Guaraldi, Mary; Shea, Thomas B

2010-01-01

Cortical neuronal activity depends on a balance between excitatory and inhibitory influences. Culturing of neurons on multi-electrode arrays (MEAs) has provided insight into the development and maintenance of neuronal networks. Herein, we seeded MEAs with murine embryonic cortical/hippocampal neurons at different densities ( 1000 cells mm −2 ) and monitored resultant spontaneous signaling. Sparsely seeded cultures displayed a large number of bipolar, rapid, high-amplitude individual signals with no apparent temporal regularity. By contrast, densely seeded cultures instead displayed clusters of signals at regular intervals. These patterns were observed even within thinner and thicker areas of the same culture. GABAergic neurons (25% of total neurons in our cultures) mediated the differential signal patterns observed above, since addition of the inhibitory antagonist bicuculline to dense cultures and hippocampal slice cultures induced the signal pattern characteristic of sparse cultures. Sparsely seeded cultures likely lacked sufficient inhibitory neurons to modulate excitatory activity. Differential seeding of MEAs can provide a unique model for analyses of pertubation in the interaction between excitatory and inhibitory function during aging and neuropathological conditions where dysregulation of GABAergic neurons is a significant component

Latin-American guidelines for opioid use in chronic nononcologic pain.

Science.gov (United States)

Lara-Solares, Argelia; Aguayo Zamora, Carlos; Amescua García, César; Garcia, João Batista Santos; Berenguel Cook, María Del Rosario; Bonilla Sierra, Patricia; Campos Kraychete, Durval; Flores Cantisani, José Alberto; Guerrero, Carlos; Guillén Núñez, María Del Rocío; Hernández Castro, John Jairo; Hernández Ortíz, Andrés; Jreige Iskandar, Aziza; Lech, Osvandré; Macías Guerra, Jacqueline; Ramírez Samayoa, Gerardo; Rangel Morillo, Edwin; Rico Pazos, María Antonieta; Sempértegui Gallegos, Manuel

2017-05-01

Latin-American experts in the use of opioids in patients with chronic nononcologic pain (CNOP) have updated existing recommendations to current Latin-American reality. Several key opinion leaders from Latin America participated in a face-to-face meeting in Guatemala (April 2015) to discuss the use of opioids in CNOP. Subgroups of experts worked on specific topics, reviewed the literature and shaped the final manuscript. The expert panel developed guidelines taking into consideration the utility of both opioid and nonopioid analgesics and factors pertaining to their efficacy, safety, adherence, administration and risks for abuse/addiction. Latin-American guidelines for the use of opioids in CNOP should improve pain relief and patients' quality of life by increasing access to these effective agents.

Peripheral δ-opioid receptors attenuate the exercise pressor reflex.

Science.gov (United States)

Leal, Anna K; Yamauchi, Katsuya; Kim, Joyce; Ruiz-Velasco, Victor; Kaufman, Marc P

2013-10-15

In rats with ligated femoral arteries, the exercise pressor reflex is exaggerated, an effect that is attenuated by stimulation of peripheral μ-opioid receptors on group IV metabosensitive afferents. In contrast, δ-opioid receptors are expressed mostly on group III mechanosensitive afferents, a finding that prompted us to determine whether stimulation of these opioid receptors could also attenuate the exaggerated exercise pressor reflex in "ligated" rats. We found femoral arterial injection of [D-Pen2,D-Pen5]enkephalin (DPDPE; 1.0 μg), a δ-opioid agonist, significantly attenuated the pressor and cardioaccelerator components of the exercise pressor reflex evoked by hindlimb muscle contraction in both rats with ligated and patent femoral arteries. DPDPE significantly decreased the pressor responses to muscle mechanoreflex activation, evoked by tendon stretch, in ligated rats only. DPDPE (1.0 μg) had no effect in either group on the pressor and cardioaccelerator responses to capsaicin (0.2 μg), which primarily stimulates group IV afferents. DPDPE (1.0 μg) had no effect on the pressor and cardioaccelerator responses to lactic acid (24 mM), which stimulates group III and IV afferents, in rats with patent femoral arteries but significantly decreased the pressor response in ligated rats. Western blots revealed the amount of protein comprising the δ-opioid receptor was greater in dorsal root ganglia innervating hindlimbs with ligated femoral arteries than in dorsal root ganglia innervating hindlimbs with patent femoral arteries. Our findings support the hypothesis that stimulation of δ-opioid receptors on group III afferents attenuated the exercise pressor reflex.

E-cigarette knowledge, attitudes, and use in opioid dependent smokers

OpenAIRE

Stein, Michael D.; Caviness, Celeste M.; Grimone, Kristin; Audet, Daniel; Borges, Allison; Anderson, Bradley J.

2014-01-01

Individuals in treatment for opioid dependence have smoking rates 3-5 times greater than U.S. prevalence rate. Traditional smoking cessation strategies have been ineffective in this population. Novel approaches are needed as well as harm reduction avenues. E-cigarettes (ecigs) may provide such a novel harm reduction and cessation opportunity but little is known about the knowledge of, attitudes about, and usage of e-cigs in opioid dependent smokers. The current study enrolled 315 opioid depen...

Opioid microinjection into raphe magnus modulates cardiorespiratory function in mice and rats.

Science.gov (United States)

Hellman, Kevin M; Mendelson, Scott J; Mendez-Duarte, Marco A; Russell, James L; Mason, Peggy

2009-11-01

The raphe magnus (RM) participates in opioid analgesia and contains pain-modulatory neurons with respiration-related discharge. Here, we asked whether RM contributes to respiratory depression, the most prevalent lethal effect of opioids. To investigate whether opioidergic transmission in RM produces respiratory depression, we microinjected a mu-opioid receptor agonist, DAMGO, or morphine into the RM of awake rodents. In mice, opioid microinjection produced sustained decreases in respiratory rate (170 to 120 breaths/min), as well as heart rate (520 to 400 beats/min). Respiratory sinus arrhythmia, indicative of enhanced parasympathetic activity, was prevalent in mice receiving DAMGO microinjection. We performed similar experiments in rats but observed no changes in breathing rate or heart rate. Both rats and mice experienced significantly more episodes of bradypnea, indicative of impaired respiratory drive, after opioid microinjection. During spontaneous arousals, rats showed less tachycardia after opioid microinjection than before microinjection, suggestive of an attenuated sympathetic tone. Thus, activation of opioidergic signaling within RM produces effects beyond analgesia, including the unwanted destabilization of cardiorespiratory function. These adverse effects on homeostasis consequent to opioid microinjection imply a role for RM in regulating the balance of sympathetic and parasympathetic tone.

Reducing the health consequences of opioid addiction in primary care.

Science.gov (United States)

Bowman, Sarah; Eiserman, Julie; Beletsky, Leo; Stancliff, Sharon; Bruce, R Douglas

2013-07-01

Addiction to prescription opioids is prevalent in primary care settings. Increasing prescription opioid use is largely responsible for a parallel increase in overdose nationally. Many patients most at risk for addiction and overdose come into regular contact with primary care providers. Lack of routine addiction screening results in missed treatment opportunities in this setting. We reviewed the literature on screening and brief interventions for addictive disorders in primary care settings, focusing on opioid addiction. Screening and brief interventions can improve health outcomes for chronic illnesses including diabetes, hypertension, and asthma. Similarly, through the use of screening and brief interventions, patients with addiction can achieve improved health outcome. A spectrum of low-threshold care options can reduce the negative health consequences among individuals with opioid addiction. Screening in primary care coupled with short interventions, including motivational interviewing, syringe distribution, naloxone prescription for overdose prevention, and buprenorphine treatment are effective ways to manage addiction and its associated risks and improve health outcomes for individuals with opioid addiction. Copyright © 2013 Elsevier Inc. All rights reserved.

[Management of opioid maintenance treatments when analgesic treatments are required].

Science.gov (United States)

Laprevote, Vincent; Geoffroy, Pierre A; Rolland, Benjamin; Leheup, Benoît F; Di Patrizio, Paolo; Cottencin, Olivier; Schwan, Raymund

2013-01-01

Opioid maintenance treatments (OMT) reduce illicit opiate use and its associated risks. They are often prescribed on a long-term basis. Physiological changes induced by long-term OMT may cause hyperalgesia and cross-tolerance to opioid agonists, which suggests that the dosage of analgesic treatment should be modified in cases of acute pain, especially when an opioid-based analgesia is required. When treatment with analgesics is necessary, OMT must be maintained, except in exceptional cases. If a split-dosing schedule is temporarily employed during OMT, the daily dosage should not be increased for analgesic purposes. Analgesic treatment must be managed differently in case of treatment with buprenorphine or methadone. With buprenorphine, non-opioid analgesics should be introduced first, if possible. If this strategy is inefficient or contraindicated, a temporary or definitive switch to methadone should be considered. In the case of methadone-based OMT, opioid analgesics should be added directly and the dosage should be adapted according to the level of pain reported by the patient. Copyright © 2013 Elsevier Masson SAS. All rights reserved.

Studies on the Protective Effects of Scutellarein against Neuronal Injury by Ischemia through the Analysis of Endogenous Amino Acids and Ca2+ Concentration Together with Ca2+-ATPase Activity

Directory of Open Access Journals (Sweden)

Hao Tang

2015-01-01

Full Text Available Scutellarin, which is extracted from the dried plant of Erigeron breviscapus, has been reported to protect the neural injury against excitotoxicity induced by ischemia. However, there are a few studies on the protective effects of scutellarein, which is the main metabolite of scutellarin in vivo. Thus, this study investigated the neuroprotective effects of scutellarein on cerebral ischemia/reperfusion in rats by bilateral common carotid artery occlusion (BCCAO model, through the analysis of endogenous amino acids using HILIC-MS/MS, and evaluation of Ca2+ concentration together with Ca2+-ATPase activity. The results showed that scutellarein having good protective effects on cerebral ischemia/reperfusion might by decreasing the excitatory amino acids, increasing the inhibitory amino acids, lowing intracellular Ca2+ level, and improving Ca2+-ATPase activity, which suggested that scutellarein might be a promising potent agent for the therapy of ischemic cerebrovascular disease.

The current status of opioid maintenance treatment in France: a survey of physicians, patients, and out-of-treatment opioid users

Directory of Open Access Journals (Sweden)

Benyamina A

2014-09-01

Full Text Available Amine Benyamina National Institute for Medical Research (INSERM U-669, Hôpital Universitaire Paul Brousse, 94804 Villejuif, France Aim: Project Access France was a national survey designed to provide real-world observations on the status of opioid dependence treatment in France. Methods: The views of physicians (n=100, patients (n=130, and out-of-treatment opioid users (n=33 were collected via interviews and questionnaires. Results: Physicians reported being moderately satisfied with treatment programs in their area (rating 6.9 out of 10. Most physicians (82% reported being concerned about misuse and diversion of medication-assisted treatment (MAT medications and 50% identified psychosocial/behavioral counseling as the key change that would most improve patient care. Among patients, the mean number of previous MAT episodes was low (1.5; 78% reported that it was easy to access a doctor to undergo MAT; 14% reported regularly or sometimes using heroin; misuse and diversion were reported in 15% and 39% of patients, respectively; and 57% of patients were not receiving psychosocial help. Out-of-treatment opioid users reported using drugs on a regular basis (42% regularly used heroin and cited 'not wanting to give up drugs completely' as the most frequent reason for staying out of MAT. Conclusion: This survey highlights a number of positive features of the open-access, GP-based treatment model for opioid dependence in France. Challenges remain with regard to continued misuse/diversion of MAT medications and limited patient access to psychosocial support. Keywords: opioid maintenance treatment, medication-assisted treatment, buprenorphine, methadone, buprenorphine–naloxone, France

Pain-related increase of excitatory transmission and decrease of inhibitory transmission in the central nucleus of the amygdala are mediated by mGluR1

Directory of Open Access Journals (Sweden)

Neugebauer Volker

2010-12-01

Full Text Available Abstract Neuroplasticity in the central nucleus of the amygdala (CeA, particularly its latero-capsular division (CeLC, is an important contributor to the emotional-affective aspects of pain. Previous studies showed synaptic plasticity of excitatory transmission to the CeLC in different pain models, but pain-related changes of inhibitory transmission remain to be determined. The CeLC receives convergent excitatory inputs from the parabrachial nucleus in the brainstem and from the basolateral amygdala (BLA. In addition, feedforward inhibition of CeA neurons is driven by glutamatergic projections from the BLA area to a cluster of GABAergic neurons in the intercalated cell masses (ITC. Using patch-clamp in rat brain slices we measured monosynaptic excitatory postsynaptic currents (EPSCs and polysynaptic inhibitory currents (IPSCs that were evoked by electrical stimulation in the BLA. In brain slices from arthritic rats, input-output functions of excitatory synaptic transmission were enhanced whereas inhibitory synaptic transmission was decreased compared to control slices from normal untreated rats. A non-NMDA receptor antagonist (NBQX blocked the EPSCs and reduced the IPSCs, suggesting that non-NMDA receptors mediate excitatory transmission and also contribute to glutamate-driven feed-forward inhibition of CeLC neurons. IPSCs were blocked by a GABAA receptor antagonist (bicuculline. Bicuculline increased EPSCs under normal conditions but not in slices from arthritic rats, which indicates a loss of GABAergic control of excitatory transmission. A metabotropic glutamate receptor subtype 1 (mGluR1 antagonist (LY367385 reversed both the increase of excitatory transmission and the decrease of inhibitory transmission in the arthritis pain model but had no effect on basal synaptic transmission in control slices from normal rats. The inhibitory effect of LY367385 on excitatory transmission was blocked by bicuculline suggesting the involvement of a GABAergic

γ-endorphin and Nα-acetyl-γ-endorphin interfere with distinct dopaminergic systems in the nucleus accumbens via opioid and non-opioid mechanisms

NARCIS (Netherlands)

Ree, J.M. van; Gaffori, O.; Kiraly, I.

1984-01-01

Low doses (10 ng) of the dopamine agonist apomorphine induced hypolocomotion when injected into the nucleus accumbens of rats. This behavioral response was antagonized by local treatment with either the opioid peptide γ-endorphin (γE) or the non-opioid peptide Nα-acetyl-γ-endorphin (AcγE) in a dose

Enhanced excitatory input to MCH neurons during developmental period of high food intake is mediated by GABA

Science.gov (United States)

Li, Ying; van den Pol, Anthony N.

2010-01-01

In contrast to the local axons of GABA neurons of the cortex and hippocampus, lateral hypothalamic neurons containing melanin concentrating hormone (MCH) and GABA send long axons throughout the brain and play key roles in energy homeostasis and mental status. In adults, MCH neurons maintain a hyperpolarized membrane potential and most of the synaptic input is inhibitory. In contrast, we found that developing MCH neurons received substantially more excitatory synaptic input. Based on gramicidicin-perforated patch recordings in hypothalamic slices from MCH-GFP transgenic mice, we found that GABA was the primary excitatory synaptic transmitter in embryonic and neonatal ages up to postnatal day 10. Surprisingly, glutamate assumed only a minor excitatory role, if any. GABA plays a complex role in developing MCH neurons, with its actions conditionally dependent on a number of factors. GABA depolarization could lead to an increase in spikes either independently or in summation with other depolarizing stimuli, or alternately, depending on the relative timing of other depolarizing events, could lead to shunting inhibition. The developmental shift from depolarizing to hyperpolarizing occurred later in the dendrites than in the cell body. Early GABA depolarization was based on a Cl− dependent inward current. An interesting secondary depolarization in mature neurons that followed an initial hyperpolarization was based on a bicarbonate mechanism. Thus during the early developmental period when food consumption is high, MCH neurons are more depolarized than in the adult, and an increased level of excitatory synaptic input to these orexigenic cells is mediated by GABA. PMID:19955372

Neurobiological mechanisms involved in nicotine dependence and reward: participation of the endogenous opioid system

Science.gov (United States)

Berrendero, Fernando; Robledo, Patricia; Trigo, José Manuel; Martín-García, Elena; Maldonado, Rafael

2010-01-01

Nicotine is the primary component of tobacco that maintains the smoking habit and develops addiction. The adaptive changes of nicotinic acetylcholine receptors produced by repeated exposure to nicotine play a crucial role in the establishment of dependence. However, other neurochemical systems also participate in the addictive effects of nicotine including glutamate, cannabinoids, GABA and opioids. This review will cover the involvement of these neurotransmitters in nicotine addictive properties, with a special emphasis on the endogenous opioid system. Thus, endogenous enkephalins and beta-endorphins acting on mu-opioid receptors are involved in nicotine rewarding effects, whereas opioid peptides derived from prodynorphin participate in nicotine aversive responses. An upregulation of mu-opioid receptors has been reported after chronic nicotine treatment that could counteract the development of nicotine tolerance, whereas the downregulation induced on kappa-opioid receptors seems to facilitate nicotine tolerance. Endogenous enkephalins acting on mu-opioid receptors also play a role in the development of physical dependence to nicotine. In agreement with these actions of the endogenous opioid system, the opioid antagonist naltrexone has shown to be effective for smoking cessation in certain subpopulations of smokers. PMID:20170672

Psychosexual disorders: A cross-sectional study among opioid-dependent individuals

Directory of Open Access Journals (Sweden)

M I Singh Sethi

2017-01-01

Full Text Available Context: Punjab is in hold of a drug abuse-related epidemic, and the prevalence of opioid misuse is increased in the last few decades. A large-scale epidemiological data on sexual disorders among opioid users are lacking in literature. Aim: The aim of this articles was to study the prevalence of sexual disorders in patients with opioid dependence. Settings and Design: A cross-sectional study was conducted at a de-addiction clinic of a tertiary care centre from Punjab, India. Methods and Materials: A total of 109 consecutive patients attending the de-addiction clinic and fulfilling the eligibility criteria were assessed for sexual dysfunction by a predesigned, pretested, semistructured questionnaire. International Index of Erectile Function (IIEF-15 was administered to all patients to explore various aspects of sexual dysfunction. Statistical Analysis: Collected data were analyzed by SPSS version 20 using appropriate statistical test. Results: Mean age of participants was 29.9 years, 67% were married and heroin was the opioid of choice for 81.7%. Impaired sexual desire (59.6% was the commonest psychosexual problem, followed by decreased orgasmic function (57.8%, erectile dysfunction (56.4%, decreased overall satisfaction (52.2%, and decreased intercourse satisfaction (46.7%. Conclusions: The prevalence of all types of sexual dysfunction was found to be statistically significant with more than 1 year of opioid use. These findings can be used to motivate the patients to enter a rehabilitation program at an earlier stage of opioid dependence. Opioid-dependent individuals should be thoroughly investigated for sexual dysfunction and its treatment should be made an integral part of de-addiction and rehabilitation program.

Development of a brief tool for monitoring aberrant behaviours among patients receiving long-term opioid therapy: The Opioid-Related Behaviours In Treatment (ORBIT) scale.

Science.gov (United States)

Larance, Briony; Bruno, Raimondo; Lintzeris, Nicholas; Degenhardt, Louisa; Black, Emma; Brown, Amanda; Nielsen, Suzanne; Dunlop, Adrian; Holland, Rohan; Cohen, Milton; Mattick, Richard P

2016-02-01

Early identification of problems is essential in minimising the unintended consequences of opioid therapy. This study aimed to develop a brief scale that identifies and quantifies recent aberrant behaviour among diverse patient populations receiving long-term opioid treatment. 40 scale items were generated via literature review and expert panel (N=19) and tested in surveys of: (i) N=41 key experts, and (ii) N=426 patients prescribed opioids >3 months (222 pain patients and 204 opioid substitution therapy (OST) patients). We employed item and scale psychometrics (exploratory factor analyses, confirmatory factor analyses and item-response theory statistics) to refine items to a brief scale. Following removal of problematic items (poor retest-reliability or wording, semantic redundancy, differential item functioning, collinearity or rarity) iterative factor analytic procedures identified a 10-item unifactorial scale with good model fit in the total sample (N=426; CFI=0.981, TLI=0.975, RMSEA=0.057), and among pain (CFI=0.969, TLI=0.960, RMSEA=0.062) and OST subgroups (CFI=0.989, TFI=0.986, RMSEA=0.051). The 10 items provided good discrimination between groups, demonstrated acceptable test-retest reliability (ICC 0.80, 95% CI 0.60-0.89; Cronbach's alpha=0.89), were moderately correlated with related constructs, including opioid dependence (SDS), depression and stress (DASS subscales) and Social Relationships and Environment domains of the WHO-QoL, and had strong face validity among advising clinicians. The Opioid-Related Behaviours In Treatment (ORBIT) scale is brief, reliable and validated for use in diverse patient groups receiving opioids. The ORBIT has potential applications as a checklist to prompt clinical discussions and as a tool to quantify aberrant behaviour and assess change over time. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Pregabalin for Opioid-Refractory Pain in a Patient with Ankylosing Spondylitis

Directory of Open Access Journals (Sweden)

Konstantinos A. Kontoangelos

2013-01-01

Full Text Available Background. Ankylosing spondylitis (AS is a systemic inflammatory disease with chronic back pain as the most common presenting symptom. We present a case of a male patient with AS reporting symptoms of severe low back pain, buttock pain, and limited spinal mobility. After chronic treatment with opioids, we administered pregabalin at a dose of 300 mg as an analgesic agent while opioids were discontinued. Findings. Pain symptoms improved progressively, and opioids were gradually discontinued without any withdrawal symptoms reported. Conclusions. Pregabalin is potentially useful in the management of pain in patients with AS while effectively managing the discontinuation of opioid treatment.

Dexmedetomidine decreases inhibitory but not excitatory neurotransmission to cardiac vagal neurons in the nucleus ambiguus.

Science.gov (United States)

Sharp, Douglas B; Wang, Xin; Mendelowitz, David

2014-07-29

Dexmedetomidine, an α2 adrenergic agonist, is a useful sedative but can also cause significant bradycardia. This decrease in heart rate may be due to decreased central sympathetic output as well as increased parasympathetic output from brainstem cardiac vagal neurons. In this study, using whole cell voltage clamp methodology, the actions of dexmedetomidine on excitatory glutamatergic and inhibitory GABAergic and glycinergic neurotransmission to parasympathetic cardiac vagal neurons in the rat nucleus ambiguus was determined. The results indicate that dexmedetomidine decreases both GABAergic and glycinergic inhibitory input to cardiac vagal neurons, with no significant effect on excitatory input. These results provide a mechanism for dexmedetomidine induced bradycardia and has implications for the management of this potentially harmful side effect. Copyright © 2014 Elsevier B.V. All rights reserved.

Critical issues on opioids in chronic non-cancer pain

DEFF Research Database (Denmark)

Eriksen, Jørgen; Sjøgren, Per; Bruera, Eduardo

2006-01-01

-related quality of life (SF-36), use of the health care system, functional capabilities, satisfaction with medical pain treatment and regular or continuous use of medications. Participants reporting pain were divided into opioid and non-opioid users. The analyses were adjusted for age, gender, concomitant use...

A text-mining analysis of the public's reactions to the opioid crisis.

Science.gov (United States)

Glowacki, Elizabeth M; Glowacki, Joseph B; Wilcox, Gary B

2017-07-19

Opioid abuse has become an epidemic in the United States. On August 25, 2016, the former Surgeon General of the United States sent an open letter to care providers asking for their help with combatting this growing health crisis. Social media forums such as Twitter allow for open discussions among the public and up-to-date exchanges of information about timely topics such as opioids. Therefore, the goal of the current study is to identify the public's reactions to the opioid epidemic by identifying the most popular topics tweeted by users. A text miner, algorithmic-driven statistical program was used to capture 73,235 original tweets and retweets posted within a 2-month time span 15 (August 15, 2016, through October 15, 2016). All tweets contained references to "opioids," "turnthetide," or similar keywords. The sets of tweets were then analyzed to identify the most prevalent topics. The most discussed topics had to do with public figures addressing opioid abuse, creating better treatment options for teen addicts, using marijuana as an alternative for managing pain, holding foreign and domestic drug makers accountable for the epidemic, promoting the "Rx for Change" campaign, addressing double standards in the perceptions and treatment of black and white opioid users, and advertising opioid recovery programs. Twitter allows users to find current information, voice their concerns, and share calls for action in response to the opioid epidemic. Monitoring the conversations about opioids that are taking place on social media forums such as Twitter can help public health officials and care providers better understand how the public is responding to this health crisis.

CXCL10 Controls Inflammatory Pain via Opioid Peptide-Containing Macrophages in Electroacupuncture

Science.gov (United States)

Wang, Ying; Gehringer, Rebekka; Mousa, Shaaban A.; Hackel, Dagmar; Brack, Alexander; Rittner, Heike L.

2014-01-01

Acupuncture is widely used for pain treatment in patients with osteoarthritis or low back pain, but molecular mechanisms remain largely enigmatic. In the early phase of inflammation neutrophilic chemokines direct opioid-containing neutrophils in the inflamed tissue and stimulate opioid peptide release and antinociception. In this study the molecular pathway and neuroimmune connections in complete Freund's adjuvant (CFA)-induced hind paw inflammation and electroacupuncture for peripheral pain control were analyzed. Free moving Wistar rats with hind paw inflammation were treated twice with electroacupuncture at GB30 (Huan Tiao - gall bladder meridian) (day 0 and 1) and analyzed for mechanical and thermal nociceptive thresholds. The cytokine profiles as well as the expression of opioid peptides were quantified in the inflamed paw. Electroacupuncture elicited long-term antinociception blocked by local injection of anti-opioid peptide antibodies (beta-endorphin, met-enkephalin, dynorphin A). The treatment altered the cytokine profile towards an anti-inflammatory pattern but augmented interferon (IFN)-gamma and the chemokine CXCL10 (IP-10: interferon gamma-inducible protein) protein and mRNA expression with concomitant increased numbers of opioid peptide-containing CXCR3+ macrophages. In rats with CFA hind paw inflammation without acupuncture repeated injection of CXCL10 triggered opioid-mediated antinociception and increase opioid-containing macrophages. Conversely, neutralization of CXCL10 time-dependently decreased electroacupuncture-induced antinociception and the number of infiltrating opioid peptide-expressing CXCR3+ macrophages. In summary, we describe a novel function of the chemokine CXCL10 - as a regulator for an increase of opioid-containing macrophages and antinociceptive mediator in inflammatory pain and as a key chemokine regulated by electroacupuncture. PMID:24732949

Reappraisal deficits promote craving and emotional distress among chronic pain patients at risk for prescription opioid misuse.

Science.gov (United States)

Garland, Eric L; Hanley, Adam W; Bedford, Carter E; Zubieta, Jon-Kar; Howard, Matthew O; Nakamura, Yoshio; Donaldson, Gary W; Froeliger, Brett

2018-06-04

A subset of chronic pain patients misuse prescription opioids as a means of regulating negative emotions. However, opioid misuse may result in deficits in emotion regulation strategies like reappraisal by virtue of the deleterious effects of chronic opioid exposure. The aim of this study was to characterize differences in reappraisal use among chronic pain patients at risk for opioid misuse and those who report taking opioids as prescribed. A sample of 127 pain patients receiving chronic opioid analgesic pharmacotherapy were classified as at risk for opioid misuse (n = 62) or taking opioids as prescribed (n = 65) using the Current Opioid Misuse Measure (COMM). The Emotion Regulation Questionnaire (ERQ) characterized use of emotion regulation strategies including reappraisal and expressive suppression. Participants also reported levels of opioid craving, emotional distress, and pain severity. Patients at risk for opioid misuse reported significantly less reappraisal use (M = 25.31, SD = 7.33) than those who reportedly took opioids as prescribed (M = 30.28, SD = 7.50), p<.001, but did differ with regard to suppression strategies. Reduced reappraisal use was associated with higher opioid craving and emotional distress that mediated the association between reappraisal deficits and opioid misuse risk. Further, there was a significant indirect effect of opioid misuse on emotional distress via reappraisal use. Opioid misuse risk was associated with reduced use of reappraisal, which in turn was associated with dysregulated negative emotions and increased appetitive drive towards consuming opioids. Studying individual differences in emotion regulation may yield efficacious intervention and prevention approaches to stem the rising tide of the prescription opioid crisis.

Polyglycerol-opioid conjugate produces analgesia devoid of side effects.

Science.gov (United States)

González-Rodríguez, Sara; Quadir, Mohiuddin A; Gupta, Shilpi; Walker, Karolina A; Zhang, Xuejiao; Spahn, Viola; Labuz, Dominika; Rodriguez-Gaztelumendi, Antonio; Schmelz, Martin; Joseph, Jan; Parr, Maria K; Machelska, Halina; Haag, Rainer; Stein, Christoph

2017-07-04

Novel painkillers are urgently needed. The activation of opioid receptors in peripheral inflamed tissue can reduce pain without central adverse effects such as sedation, apnoea, or addiction. Here, we use an unprecedented strategy and report the synthesis and analgesic efficacy of the standard opioid morphine covalently attached to hyperbranched polyglycerol (PG-M) by a cleavable linker. With its high-molecular weight and hydrophilicity, this conjugate is designed to selectively release morphine in injured tissue and to prevent blood-brain barrier permeation. In contrast to conventional morphine, intravenous PG-M exclusively activated peripheral opioid receptors to produce analgesia in inflamed rat paws without major side effects such as sedation or constipation. Concentrations of morphine in the brain, blood, paw tissue, and in vitro confirmed the selective release of morphine in the inflamed milieu. Thus, PG-M may serve as prototype of a peripherally restricted opioid formulation designed to forego central and intestinal side effects.

Opioids Switching with Transdermal Systems in Chronic Cancer Pain

Directory of Open Access Journals (Sweden)

Barbarisi M

2009-05-01

Full Text Available Abstract Background Due to tolerance development and adverse side effects, chronic pain patients frequently need to be switched to alternative opioid therapy Objective To assess the efficacy and tolerability of an alternative transdermally applied (TDS opioid in patients with chronic cancer pain receiving insufficient analgesia using their present treatment. Methods A total of 32 patients received alternative opioid therapy, 16 were switched from buprenorphine to fentanyl and 16 were switched from fentanyl to buprenorphine. The dosage used was 50% of that indicated in equipotency conversion tables. Pain relief was assessed at weekly intervals for the next 3 weeks Results Pain relief as assessed by VAS, PPI, and PRI significantly improved (p Conclusion Opioid switching at 50% of the calculated equianalgesic dose produced a significant reduction in pain levels and rescue medication. The incidence of side effects decreased and no new side effects were noted. Further studies are required to provide individualized treatment for patients according to their different types of cancer.

Atypical Opioid Mechanisms of Control of Injury-Induced Cutaneous Pain by Delta Receptors

Science.gov (United States)

2016-07-01

treat, and current opioids (i.e. mu opioid receptor agonists such as morphine) cause unacceptable side effects including addiction . Injuries suffered...treat, and current opioids that act on mu opioid receptors such as morphine generate significant side effects including addiction . War-related...al., J Neurosci Methods, 1994), starting with 0.1 g and ending with 2.0 g filament as cutoff value. As shown in Figure 2, our preliminary experiments

[Effect of opioid receptors on acute stress-induced changes in recognition memory].

Science.gov (United States)

Liu, Ying; Wu, Yu-Wei; Qian, Zhao-Qiang; Yan, Cai-Fang; Fan, Ka-Min; Xu, Jin-Hui; Li, Xiao; Liu, Zhi-Qiang

2016-12-25

Although ample evidence has shown that acute stress impairs memory, the influences of acute stress on different phases of memory, such as acquisition, consolidation and retrieval, are different. Experimental data from both human and animals support that endogenous opioid system plays a role in stress, as endogenous opioid release is increased and opioid receptors are activated during stress experience. On the other hand, endogenous opioid system mediates learning and memory. The aim of the present study was to investigate the effect of acute forced swimming stress on recognition memory of C57 mice and the role of opioid receptors in this process by using a three-day pattern of new object recognition task. The results showed that 15-min acute forced swimming damaged the retrieval of recognition memory, but had no effect on acquisition and consolidation of recognition memory. No significant change of object recognition memory was found in mice that were given naloxone, an opioid receptor antagonist, by intraperitoneal injection. But intraperitoneal injection of naloxone before forced swimming stress could inhibit the impairment of recognition memory retrieval caused by forced swimming stress. The results of real-time PCR showed that acute forced swimming decreased the μ opioid receptor mRNA levels in whole brain and hippocampus, while the injection of naloxone before stress could reverse this change. These results suggest that acute stress may impair recognition memory retrieval via opioid receptors.

Striatal μ-opioid receptor availability predicts cold pressor pain threshold in healthy human subjects

DEFF Research Database (Denmark)

Hagelberg, Nora; Aalto, Sargo; Tuominen, Lauri

2012-01-01

the potential associations between μ-opioid receptor BP(ND) and psychophysical measures. The results show that striatal μ-opioid receptor BP(ND) predicts cold pressor pain threshold, but not cold pressor pain tolerance or tactile sensitivity. This finding suggests that striatal μ-opioid receptor density......Previous PET studies in healthy humans have shown that brain μ-opioid receptor activation during experimental pain is associated with reductions in the sensory and affective ratings of the individual pain experience. The aim of this study was to find out whether brain μ-opioid receptor binding...... at the resting state, in absence of painful stimulation, can be a long-term predictor of experimental pain sensitivity. We measured μ-opioid receptor binding potential (BP(ND)) with μ-opioid receptor selective radiotracer [(11)C]carfentanil and positron emission tomography (PET) in 12 healthy male subjects...

Epidemiologic trends and geographic patterns of fatal opioid intoxications in Connecticut, USA: 1997-2007.

Science.gov (United States)

Green, Traci C; Grau, Lauretta E; Carver, H Wayne; Kinzly, Mark; Heimer, Robert

2011-06-01

The leading cause of injury death among adults in Connecticut (CT), USA is drug poisonings. We analyzed the epidemiology and geographic distribution of opioid-involved accidental drug-involved intoxication deaths ("overdoses") in CT over an 11-year period. We reviewed data from 1997 to 2007 on all adult accidental/undetermined drug intoxication deaths in CT that were referred to the Office of the Chief Medical Examiner (OCME). Regression analyses were conducted to uncover risk factors for fatal opioid-involved intoxications and to compare heroin- to prescription opioid- and methadone-involved deaths. Death locations were mapped to visualize differences in the geographic patterns of overdose by opioid type. Of the 2900 qualifying deaths, 2231 (77%) involved opioids. Trends over time revealed increases in total opioid-related deaths although heroin-related deaths remained constant. Methadone, oxycodone and fentanyl, the most frequently cited prescription opioids, exhibited significant increases in opioid deaths. Prescription opioid-only deaths were more likely to involve other medications (e.g., benzodiazepines) and to have occurred among residents of a suburban or small town location, compared to heroin-involved or methadone-involved deaths. Heroin-only deaths tended to occur among non-Whites, were more likely to involve alcohol or cocaine and to occur in public locations and large cities. The epidemiology of fatal opioid overdose in CT exhibits distinct longitudinal, risk factor, and geographic differences by opioid type. Each of these trends has implications for public health and prevention efforts. Copyright © 2010 Elsevier Ireland Ltd. All rights reserved.

Opioid Prescribing After Curative-Intent Surgery: A Qualitative Study Using the Theoretical Domains Framework.

Science.gov (United States)

Lee, Jay S; Parashar, Vartika; Miller, Jacquelyn B; Bremmer, Samantha M; Vu, Joceline V; Waljee, Jennifer F; Dossett, Lesly A

2018-07-01

Excessive opioid prescribing is common after curative-intent surgery, but little is known about what factors influence prescribing behaviors among surgeons. To identify targets for intervention, we performed a qualitative study of opioid prescribing after curative-intent surgery using the Theoretical Domains Framework, a well-established implementation science method for identifying factors influencing healthcare provider behavior. Prior to data collection, we constructed a semi-structured interview guide to explore decision making for opioid prescribing. We then conducted interviews with surgical oncology providers at a single comprehensive cancer center. Interviews were recorded, transcribed verbatim, then independently coded by two investigators using the Theoretical Domains Framework to identify theoretical domains relevant to opioid prescribing. Relevant domains were then linked to behavior models to select targeted interventions likely to improve opioid prescribing. Twenty-one subjects were interviewed from November 2016 to May 2017, including attending surgeons, resident surgeons, physician assistants, and nurses. Five theoretical domains emerged as relevant to opioid prescribing: environmental context and resources; social influences; beliefs about consequences; social/professional role and identity; and goals. Using these domains, three interventions were identified as likely to change opioid prescribing behavior: (1) enablement (deploy nurses during preoperative visits to counsel patients on opioid use); (2) environmental restructuring (provide on-screen prompts with normative data on the quantity of opioid prescribed); and (3) education (provide prescribing guidelines). Key determinants of opioid prescribing behavior after curative-intent surgery include environmental and social factors. Interventions targeting these factors are likely to improve opioid prescribing in surgical oncology.

Implementing opioid substitution in Lebanon: Inception and challenges.

Science.gov (United States)

El-Khoury, Joseph; Abbas, Zeinab; Nakhle, Pascale E; Matar, Marie-Therese

2016-05-01

Opioid Substitution Treatment (OST) is a firmly established method of treating and managing dependence to opioids in Europe, the US and rest of the developed world. It has a solid evidence base and a positive safety track record. Dissemination of its practice, in parallel to the acceptance of harm reduction as an effective approach, is still timid in low and middle Income countries. After years of advocacy on the parts of clinicians and the voluntary sector, the government of Lebanon launched a national opioid substitution program in 2011 using buprenorphine as the substance of substitution. Lebanon is one of the first countries in the MENA region to establish such a program despite a difficult socio-political context. This paper provides the background of harm reduction efforts in the region and presents the outline of the program from inception to present date. Challenges and recommendations for the future are also discussed. The Lebanese experience with opioid substitution is encouraging so far and can be used as a template for others in the region who might be contemplating broadening the range of services available to tackle addiction to heroin and related substances. Copyright © 2016 Elsevier B.V. All rights reserved.

Spatiotemporal expression of endogenous opioid processing enzymes in mouse uterus at peri-implantation.

Science.gov (United States)

Wu, Weiwei; Kong, Shuangbo; Wang, Bingyan; Chen, Yongjie; Wang, Haibin

2016-02-01

Successful implantation requires intimate interactions between a competent blastocyst and a receptive uterus. We recently demonstrated that the aberrant activation of opioid signaling by exogenous ligands adversely affects preimplantation embryonic development and subsequent implantation in mice. However, the underlying machinery governing the dynamic homeostasis of the endogenous opioid system in the uterus during early pregnancy remains elusive. We now show that all three major endogenous opioid precursors are spatiotemporally expressed in the uterus during early pregnancy. Moreover, we observe the well-coordinated expression of the synthetic enzyme prohormone convertases 1/3 (PC1/3) at lower levels and of its inhibitor proprotein convertase subtilisin/kexin type 1 inhibitor (Pcsk1n) and the degrading enzyme membrane metallo-endopeptidase (MME) at higher levels in the receptive uterus. Both estrogen and progestin tend to reduce the uterine levels of opioid ligand precursors in the ovariectomized mouse model. This tight regulation of the endogenous opioid system by PC1/3, Pcsk1n and MME has been further confirmed in physiologically related pseudopregnancy and delayed implantation mouse models. The coordinated regulation of opioid precursor biosynthesis and metabolism helps to create appropriate opioid signaling ensuring uterine receptivity for implantation. Thus, endogenous uterine opioid levels are primarily determined by the coordinated expressions of PC1/3, Pcsk1n and MME under the influence of ovarian progestin and estrogen. Our findings raise an additional cautionary note regarding the effects of opioid abuse on early pregnancy events.

Opioid and nicotine receptors affect growth regulation of human lung cancer cell lines

International Nuclear Information System (INIS)

Maneckjee, R.; Minna, J.D.

1990-01-01

Using specific radioactively-labeled ligands, the authors find that lung cancer cell lines of diverse histologic types express multiple, high-affinity membrane receptors for μ, δ, and κ opioid agonists and for nicotine and α-bungarotoxin. These receptors are biologically active because cAMP levels decreased in lung cancer cells after opioid and nicotine application. Nicotine at concentrations found in the blood of smokers had no effect on in vitro lung cancer cell growth, whereas μ, δ, and κ opioid agonists at low concentrations inhibited lung cancer growth in vitro. They also found that lung cancer cells expressed various combinations of immunoreactive opioid peptides (β-endorphin, enkephalin, or dynorphin), suggesting the participation of opioids in a negative autocrine loop or tumor-suppressing system. Due to the almost universal exposure of patients with lung cancer to nicotine, they tested whether nicotine affected the response of lung cancer cell growth to opioids and found that nicotine at concentrations of 100-200 nM partially or totally reversed opioid-induced growth inhibition in 9/14 lung cancer cell lines. These in vitro results for lung cancer cells suggest that opioids could function as part of a tumor suppressor system and that nicotine can function to circumvent this system in the pathogenesis of lung cancer

Opioid and nicotine receptors affect growth regulation of human lung cancer cell lines

Energy Technology Data Exchange (ETDEWEB)

Maneckjee, R.; Minna, J.D. (National Cancer Institute-Navy Medical Oncology Branch, Bethesda, MD (USA) Uniformed Services Univ. of the Health Sciences, Bethesda, MD (USA))

1990-05-01

Using specific radioactively-labeled ligands, the authors find that lung cancer cell lines of diverse histologic types express multiple, high-affinity membrane receptors for {mu}, {delta}, and {kappa} opioid agonists and for nicotine and {alpha}-bungarotoxin. These receptors are biologically active because cAMP levels decreased in lung cancer cells after opioid and nicotine application. Nicotine at concentrations found in the blood of smokers had no effect on in vitro lung cancer cell growth, whereas {mu}, {delta}, and {kappa} opioid agonists at low concentrations inhibited lung cancer growth in vitro. They also found that lung cancer cells expressed various combinations of immunoreactive opioid peptides ({beta}-endorphin, enkephalin, or dynorphin), suggesting the participation of opioids in a negative autocrine loop or tumor-suppressing system. Due to the almost universal exposure of patients with lung cancer to nicotine, they tested whether nicotine affected the response of lung cancer cell growth to opioids and found that nicotine at concentrations of 100-200 nM partially or totally reversed opioid-induced growth inhibition in 9/14 lung cancer cell lines. These in vitro results for lung cancer cells suggest that opioids could function as part of a tumor suppressor system and that nicotine can function to circumvent this system in the pathogenesis of lung cancer.

Sleep-disordered breathing decreases after opioid withdrawal: results of a prospective controlled trial.

Science.gov (United States)

Schwarzer, Andreas; Aichinger-Hinterhofer, Marie; Maier, Christoph; Vollert, Jan; Walther, Jörg Werner

2015-11-01

An increased cardiovascular event rate in elderly patients under opioid medications was recently reported. One reason for this increase could be the occurrence of nocturnal apnea and hypoxia, as a consequence of sleep-disordered breathing (SDB). Using a controlled study, we prospectively analyzed SDB using polysomnography in a total of 18 patients before and after opioid withdrawal (opioid withdrawal group [OG]) and 14 patients before and after comprehensive pain management (without any strong-acting opioids) who served as the control group (CG). To analyze the differences, unpaired/paired t tests and Mann-Whitney U tests/Wilcoxon rank tests were used. At baseline, the OG presented more nocturnal apneas/hypopneas than the CG with an apnea-hypopnea index (AHI) of 41.4 ± 27.8 vs 21.8 ± 15.9 (P = 0.018). After treatment, the AHI decreased significantly only in the withdrawal group (OG: 16.7 ± 8.9; CG: 20.1 ± 12.9) (P opioid withdrawal and in none of the patients after withdrawal (P opioid intake; these findings may explain the opioid-associated cardiovascular morbidity. Thus, SDB may be a risk at lower opioid doses than hitherto described, and particular caution should be exercised in patients with comorbidities that might make them vulnerable to the consequences of SDB.

Evidence for opioid involvement in the motivation to sing.

Science.gov (United States)

Riters, Lauren V

2010-03-01

Songbirds produce high rates of song within multiple social contexts, suggesting that they are highly motivated to sing and that song production itself may be rewarding. Progress has been made in understanding the neural basis of song learning and sensorimotor processing, however little is known about neurobiological mechanisms regulating the motivation to sing. Neural systems involved in motivation and reward have been conserved across species and in songbirds are neuroanatomically well-positioned to influence the song control system. Opioid neuropeptides within these systems play a primary role in hedonic reward, at least in mammals. In songbirds, opioid neuropeptides and receptors are found throughout the song control system and within several brain regions implicated in both motivation and reward, including the medial preoptic nucleus (POM) and ventral tegmental area (VTA). Growing research shows these regions to play a role in birdsong that differs depending upon whether song is sexually motivated in response to a female, used for territorial defense or sung as part of a flock but not directed towards an individual (undirected song). Opioid pharmacological manipulations and immunocytochemical data demonstrate a role for opioid activity possibly within VTA and POM in the regulation of song production. Although future research is needed, data suggest that opioids may be most critically involved in reinforcing song that does not result in any obvious form of immediate externally mediated reinforcement, such as undirected song produced in large flocks or during song learning. Data are reviewed supporting the idea that dopamine activity underlies the motivation or drive to sing, but that opioid release is what makes song production rewarding. Copyright 2009 Elsevier B.V. All rights reserved.