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Bin C, Xiaohui W, Mengrou S, Xin L, Ting Z, Ping G. Preliminary evaluation of the efficacy and safety of brimonidine for general anesthesia. BMC Anesthesiol 2021; 21:305. [PMID: 34861822 PMCID: PMC8641169 DOI: 10.1186/s12871-021-01516-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2021] [Accepted: 11/08/2021] [Indexed: 12/04/2022] Open
Abstract
Background To determine the hypnotic and analgesic effects of brimonidine, and evaluate its efficacy and safety for general anesthesia. Potentiation of pentobarbital sleeping time following brimonidine administration was observed in mice, as was the analgesic activity of brimonidine. Methods The median effective dose (ED50) and lethal dose (LD50) of intraperitoneally injected brimonidine were determined in hypnotized mice. In addition, the LD50 of intravenously injected brimonidine, and ED50 of intravenously, intramuscularly, and intrarectally injected brimonidine in hypnotized rabbits were determined. Finally, the synergistic anesthetic effect of brimonidine and chloral hydrate was evaluated in rabbits. Results Intraperitoneal injection of 10 mg/kg brimonidine enhanced the hypnotic effect of a threshold dose of pentobarbital. Intraperitoneally injected brimonidine produced dose-related analgesic effects in mice. The ED50 of intraperitoneally administered brimonidine in hypnotized mice was 75.7 mg/kg and the LD50 was 379 mg/kg. ED50 values of intravenous, intramuscular, and intrarectal brimonidine for hypnosis in rabbits were 5.2 mg/kg, 8.8 mg/kg, and 8.7 mg/kg, respectively; the LD50 of intravenous brimonidine was 146 mg/kg. Combined intravenous administration of 0.6 mg/kg brimonidine and 0.03 g/kg chloral hydrate had a synergistic anesthetic effect. Conclusions Brimonidine elicited hypnotic and analgesic effects after systemic administration and exhibited safety. Moreover, brimonidine enhanced the effects of other types of narcotics when combined. Supplementary Information The online version contains supplementary material available at 10.1186/s12871-021-01516-1.
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Affiliation(s)
- Chen Bin
- Tianjin Institute of Medical & Pharmaceutical Sciences, No. 79 Duolun Road, Heping District, Tianjin, 300020, China
| | - Wang Xiaohui
- Tianjin Institute of Medical & Pharmaceutical Sciences, No. 79 Duolun Road, Heping District, Tianjin, 300020, China
| | - Shi Mengrou
- Tianjin Institute of Medical & Pharmaceutical Sciences, No. 79 Duolun Road, Heping District, Tianjin, 300020, China
| | - Li Xin
- Tianjin Institute of Medical & Pharmaceutical Sciences, No. 79 Duolun Road, Heping District, Tianjin, 300020, China
| | - Zhang Ting
- Tianjin Institute of Medical & Pharmaceutical Sciences, No. 79 Duolun Road, Heping District, Tianjin, 300020, China
| | - Gao Ping
- Tianjin Institute of Medical & Pharmaceutical Sciences, No. 79 Duolun Road, Heping District, Tianjin, 300020, China.
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Berthiaume S, Abdallah K, Blais V, Gendron L. Alleviating pain with delta opioid receptor agonists: evidence from experimental models. J Neural Transm (Vienna) 2020; 127:661-672. [PMID: 32189076 DOI: 10.1007/s00702-020-02172-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2019] [Accepted: 03/06/2020] [Indexed: 12/11/2022]
Abstract
The use of opioids for the relief of pain and headache disorders has been studied for years. Nowadays, particularly because of its ability to produce analgesia in various pain models, delta opioid receptor (DOPr) emerges as a promising target for the development of new pain therapies. Indeed, their potential to avoid the unwanted effects commonly observed with clinically used opioids acting at the mu opioid receptor (MOPr) suggests that DOPr agonists could be a therapeutic option. In this review, we discuss the use of opioids in the management of pain in addition to describing the evidence of the analgesic potency of DOPr agonists in animal models.
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Affiliation(s)
- Sophie Berthiaume
- Département de Pharmacologie-Physiologie, Institut de Pharmacologie de Sherbrooke, Centre de Recherche du Centre Hospitalier Universitaire de Sherbrooke, Faculté de médecine et des sciences de la santé, Université de Sherbrooke, 3001, 12th Avenue North, Sherbrooke, QC, J1H 5N4, Canada
| | - Khaled Abdallah
- Département de Pharmacologie-Physiologie, Institut de Pharmacologie de Sherbrooke, Centre de Recherche du Centre Hospitalier Universitaire de Sherbrooke, Faculté de médecine et des sciences de la santé, Université de Sherbrooke, 3001, 12th Avenue North, Sherbrooke, QC, J1H 5N4, Canada
| | - Véronique Blais
- Département de Pharmacologie-Physiologie, Institut de Pharmacologie de Sherbrooke, Centre de Recherche du Centre Hospitalier Universitaire de Sherbrooke, Faculté de médecine et des sciences de la santé, Université de Sherbrooke, 3001, 12th Avenue North, Sherbrooke, QC, J1H 5N4, Canada
| | - Louis Gendron
- Département de Pharmacologie-Physiologie, Institut de Pharmacologie de Sherbrooke, Centre de Recherche du Centre Hospitalier Universitaire de Sherbrooke, Faculté de médecine et des sciences de la santé, Université de Sherbrooke, 3001, 12th Avenue North, Sherbrooke, QC, J1H 5N4, Canada.
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Larson CM, Wilcox GL, Fairbanks CA. The Study of Pain in Rats and Mice. Comp Med 2019; 69:555-570. [PMID: 31822322 PMCID: PMC6935695 DOI: 10.30802/aalas-cm-19-000062] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2019] [Revised: 07/17/2019] [Accepted: 09/30/2019] [Indexed: 01/07/2023]
Abstract
Pain is a clinical syndrome arising from a variety of etiologies in a heterogeneous population, which makes successfully treating the individual patient difficult. Organizations and governments recognize the need for tailored and specific therapies, which drives pain research. This review summarizes the different types of pain assessments currently being used and the various rodent models that have been developed to recapitulate the human pain condition.
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Affiliation(s)
- Christina M Larson
- Comparative and Molecular Biosciences, University of Minnesota College of Veterinary Medicine, St Paul, Minnesota
| | - George L Wilcox
- Departments of Neuroscience, University of Minnesota Medical School, Minneapolis, Minnesota
| | - Carolyn A Fairbanks
- Departments of Neuroscience, University of Minnesota Medical School, Minneapolis, Minnesota;,
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Fan W, Wang H, Zhang Y, Loh HH, Law PY, Xu C. Morphine regulates adult neurogenesis and contextual memory extinction via the PKCε/Prox1 pathway. Neuropharmacology 2018; 141:126-138. [PMID: 30170081 DOI: 10.1016/j.neuropharm.2018.08.031] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2018] [Revised: 08/21/2018] [Accepted: 08/24/2018] [Indexed: 02/08/2023]
Abstract
We have previously reported that the miR-181a/Prox1/Notch1 pathway mediates the effect of morphine on modulating lineage-specific differentiation of adult neural stem/progenitor cells (NSPCs) via a PKCε-dependent pathway, whereas fentanyl shows no such effect. However, the role of the PKCε/Prox1 pathway in mediating drug-associated contextual memory remains unknown. The current study investigated the effect of PKCε/Prox1 on morphine-induced inhibition of adult neurogenesis and drug-associated contextual memory in mice, while the effect of fentanyl was tested simultaneously. By using BrdU labeling, we were able to examine the lineages of differentiated NSPCs in adult DG. PKCε knockout blocked morphine's effects on inducing in vivo astrocyte-preferential differentiation of NSPCs, but did not alter NSPC lineages upon fentanyl treatment. Inhibited adult neurogenesis further resulted in prolonged extinction and enhanced reinstatement of morphine-induced CPP, as well as prolonged extinction of space reference memory indicated by the Morris water maze paradigm. However, after fentanyl administration, no significant changes were found between wild-type and PKCε knockout mice, during either CPP or water maze tasks. When the lentivirus encoding Nestin-promoter-controlled Prox1 cDNA was injected into hippocampi of wildtype and PKCε knockout adult mice to modulate PKCε/Prox1 activity, similar effects were discovered in adult mice injected with lentivirus encoding Prox1, and more dramatic effects were found in PKCε knockout mice with concurrent Prox1 overexpression. In conclusion, morphine mediates lineage-specific NSPC differentiation, inhibits adult neurogenesis and regulates contextual memory retention via the PKCε/Prox1 pathway, which are implicated in the eventual context-associated relapse.
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Affiliation(s)
- Wenxiang Fan
- State Key Laboratory of Natural Medicines, School of Basic Medicine and Clinical Pharmacy, China Pharmaceutical University, 24 Tong Jia Xiang, Nanjing, Jiangsu, 210009, People's Republic of China
| | - Helei Wang
- State Key Laboratory of Natural Medicines, School of Basic Medicine and Clinical Pharmacy, China Pharmaceutical University, 24 Tong Jia Xiang, Nanjing, Jiangsu, 210009, People's Republic of China
| | - Yue Zhang
- Department of Pharmacology, University of Minnesota Medical School, 6-120 Jackson Hall, 321 Church St. SE, Minneapolis, MN, 55455, USA
| | - Horace H Loh
- Department of Pharmacology, University of Minnesota Medical School, 6-120 Jackson Hall, 321 Church St. SE, Minneapolis, MN, 55455, USA
| | - Ping-Yee Law
- Department of Pharmacology, University of Minnesota Medical School, 6-120 Jackson Hall, 321 Church St. SE, Minneapolis, MN, 55455, USA
| | - Chi Xu
- State Key Laboratory of Natural Medicines, School of Basic Medicine and Clinical Pharmacy, China Pharmaceutical University, 24 Tong Jia Xiang, Nanjing, Jiangsu, 210009, People's Republic of China.
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Gendron L, Cahill CM, von Zastrow M, Schiller PW, Pineyro G. Molecular Pharmacology of δ-Opioid Receptors. Pharmacol Rev 2017; 68:631-700. [PMID: 27343248 DOI: 10.1124/pr.114.008979] [Citation(s) in RCA: 86] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Opioids are among the most effective analgesics available and are the first choice in the treatment of acute severe pain. However, partial efficacy, a tendency to produce tolerance, and a host of ill-tolerated side effects make clinically available opioids less effective in the management of chronic pain syndromes. Given that most therapeutic opioids produce their actions via µ-opioid receptors (MOPrs), other targets are constantly being explored, among which δ-opioid receptors (DOPrs) are being increasingly considered as promising alternatives. This review addresses DOPrs from the perspective of cellular and molecular determinants of their pharmacological diversity. Thus, DOPr ligands are examined in terms of structural and functional variety, DOPrs' capacity to engage a multiplicity of canonical and noncanonical G protein-dependent responses is surveyed, and evidence supporting ligand-specific signaling and regulation is analyzed. Pharmacological DOPr subtypes are examined in light of the ability of DOPr to organize into multimeric arrays and to adopt multiple active conformations as well as differences in ligand kinetics. Current knowledge on DOPr targeting to the membrane is examined as a means of understanding how these receptors are especially active in chronic pain management. Insight into cellular and molecular mechanisms of pharmacological diversity should guide the rational design of more effective, longer-lasting, and better-tolerated opioid analgesics for chronic pain management.
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Affiliation(s)
- Louis Gendron
- Département de Pharmacologie-Physiologie, Faculté de médecine et des sciences de la santé, Université de Sherbrooke, Centre de Recherche du CHU de Sherbrooke, Centre d'excellence en neurosciences de l'Univeristé de Sherbrooke, and Institut de Pharmacologie de Sherbrooke, Sherbrooke, Quebec, Canada (L.G.); Québec Pain Research Network, Sherbrooke, Quebec, Canada (L.G.); Departments of Anesthesiology and Perioperative Care and Pharmacology, University of California, Irvine, California (C.M.C.); Department of Biomedical and Molecular Sciences, Queen's University, Kingston, Ontario, Canada (C.M.C.); Departments of Psychiatry and Cellular and Molecular Pharmacology, University of California, San Francisco, California (M.v.Z.); Laboratory of Chemical Biology and Peptide Research, Clinical Research Institute of Montréal, Montreal, Quebec, Canada (P.W.S.); and Departments of Psychiatry, Pharmacology, and Neurosciences, Faculty of Medicine, University of Montréal and Sainte-Justine Hospital Research Center, Montreal, Quebec, Canada (G.P.)
| | - Catherine M Cahill
- Département de Pharmacologie-Physiologie, Faculté de médecine et des sciences de la santé, Université de Sherbrooke, Centre de Recherche du CHU de Sherbrooke, Centre d'excellence en neurosciences de l'Univeristé de Sherbrooke, and Institut de Pharmacologie de Sherbrooke, Sherbrooke, Quebec, Canada (L.G.); Québec Pain Research Network, Sherbrooke, Quebec, Canada (L.G.); Departments of Anesthesiology and Perioperative Care and Pharmacology, University of California, Irvine, California (C.M.C.); Department of Biomedical and Molecular Sciences, Queen's University, Kingston, Ontario, Canada (C.M.C.); Departments of Psychiatry and Cellular and Molecular Pharmacology, University of California, San Francisco, California (M.v.Z.); Laboratory of Chemical Biology and Peptide Research, Clinical Research Institute of Montréal, Montreal, Quebec, Canada (P.W.S.); and Departments of Psychiatry, Pharmacology, and Neurosciences, Faculty of Medicine, University of Montréal and Sainte-Justine Hospital Research Center, Montreal, Quebec, Canada (G.P.)
| | - Mark von Zastrow
- Département de Pharmacologie-Physiologie, Faculté de médecine et des sciences de la santé, Université de Sherbrooke, Centre de Recherche du CHU de Sherbrooke, Centre d'excellence en neurosciences de l'Univeristé de Sherbrooke, and Institut de Pharmacologie de Sherbrooke, Sherbrooke, Quebec, Canada (L.G.); Québec Pain Research Network, Sherbrooke, Quebec, Canada (L.G.); Departments of Anesthesiology and Perioperative Care and Pharmacology, University of California, Irvine, California (C.M.C.); Department of Biomedical and Molecular Sciences, Queen's University, Kingston, Ontario, Canada (C.M.C.); Departments of Psychiatry and Cellular and Molecular Pharmacology, University of California, San Francisco, California (M.v.Z.); Laboratory of Chemical Biology and Peptide Research, Clinical Research Institute of Montréal, Montreal, Quebec, Canada (P.W.S.); and Departments of Psychiatry, Pharmacology, and Neurosciences, Faculty of Medicine, University of Montréal and Sainte-Justine Hospital Research Center, Montreal, Quebec, Canada (G.P.)
| | - Peter W Schiller
- Département de Pharmacologie-Physiologie, Faculté de médecine et des sciences de la santé, Université de Sherbrooke, Centre de Recherche du CHU de Sherbrooke, Centre d'excellence en neurosciences de l'Univeristé de Sherbrooke, and Institut de Pharmacologie de Sherbrooke, Sherbrooke, Quebec, Canada (L.G.); Québec Pain Research Network, Sherbrooke, Quebec, Canada (L.G.); Departments of Anesthesiology and Perioperative Care and Pharmacology, University of California, Irvine, California (C.M.C.); Department of Biomedical and Molecular Sciences, Queen's University, Kingston, Ontario, Canada (C.M.C.); Departments of Psychiatry and Cellular and Molecular Pharmacology, University of California, San Francisco, California (M.v.Z.); Laboratory of Chemical Biology and Peptide Research, Clinical Research Institute of Montréal, Montreal, Quebec, Canada (P.W.S.); and Departments of Psychiatry, Pharmacology, and Neurosciences, Faculty of Medicine, University of Montréal and Sainte-Justine Hospital Research Center, Montreal, Quebec, Canada (G.P.)
| | - Graciela Pineyro
- Département de Pharmacologie-Physiologie, Faculté de médecine et des sciences de la santé, Université de Sherbrooke, Centre de Recherche du CHU de Sherbrooke, Centre d'excellence en neurosciences de l'Univeristé de Sherbrooke, and Institut de Pharmacologie de Sherbrooke, Sherbrooke, Quebec, Canada (L.G.); Québec Pain Research Network, Sherbrooke, Quebec, Canada (L.G.); Departments of Anesthesiology and Perioperative Care and Pharmacology, University of California, Irvine, California (C.M.C.); Department of Biomedical and Molecular Sciences, Queen's University, Kingston, Ontario, Canada (C.M.C.); Departments of Psychiatry and Cellular and Molecular Pharmacology, University of California, San Francisco, California (M.v.Z.); Laboratory of Chemical Biology and Peptide Research, Clinical Research Institute of Montréal, Montreal, Quebec, Canada (P.W.S.); and Departments of Psychiatry, Pharmacology, and Neurosciences, Faculty of Medicine, University of Montréal and Sainte-Justine Hospital Research Center, Montreal, Quebec, Canada (G.P.)
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Alongkronrusmee D, Chiang T, van Rijn RM. Involvement of delta opioid receptors in alcohol withdrawal-induced mechanical allodynia in male C57BL/6 mice. Drug Alcohol Depend 2016; 167:190-8. [PMID: 27567436 PMCID: PMC5325684 DOI: 10.1016/j.drugalcdep.2016.08.017] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/15/2016] [Revised: 07/25/2016] [Accepted: 08/15/2016] [Indexed: 01/10/2023]
Abstract
BACKGROUND As a legal drug, alcohol is commonly abused and it is estimated that 17 million adults in the United States suffer from alcohol use disorder. Heavy alcoholics can experience withdrawal symptoms including anxiety and mechanical allodynia that can facilitate relapse. The molecular mechanisms underlying this phenomenon are not well understood, which stifles development of new therapeutics. Here we investigate whether delta opioid receptors (DORs) play an active role in alcohol withdrawal-induced mechanical allodynia (AWiMA) and if DOR agonists may provide analgesic relief from AWiMA. METHODS To study AWiMA, adult male wild-type and DOR knockout C57BL/6 mice were exposed to alcohol by a voluntary drinking model or oral gavage exposure model, which we developed and validated here. We also used the DOR-selective agonist TAN-67 and antagonist naltrindole to examine the involvement of DORs in AWiMA, which was measured using a von Frey model of mechanical allodynia. RESULTS We created a robust model of alcohol withdrawal-induced anxiety and mechanical allodynia by orally gavaging mice with 3g/kg alcohol for three weeks. AWiMA was exacerbated and prolonged in DOR knockout mice as well as by pharmacological blockade of DORs compared to control mice. However, analgesia induced by TAN-67 was attenuated during withdrawal in alcohol-gavaged mice. CONCLUSIONS DORs appear to play a protective role in the establishment of AWiMA. Our current results indicate that DORs could be targeted to prevent or reduce the development of AWiMA during alcohol use; however, DORs may be a less suitable target to treat AWiMA during active withdrawal.
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Affiliation(s)
- Doungkamol Alongkronrusmee
- Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, West Lafayette, Indiana 47907
| | - Terrance Chiang
- Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, West Lafayette, Indiana 47907
| | - Richard M. van Rijn
- Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, West Lafayette, Indiana 47907,Corresponding author: Richard M. van Rijn;
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Xu C, Zheng H, Loh HH, Law PY. Morphine Promotes Astrocyte-Preferential Differentiation of Mouse Hippocampal Progenitor Cells via PKCε-Dependent ERK Activation and TRBP Phosphorylation. Stem Cells 2015; 33:2762-72. [PMID: 26012717 DOI: 10.1002/stem.2055] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2014] [Accepted: 05/12/2015] [Indexed: 01/24/2023]
Abstract
Previously we have shown that morphine regulates adult neurogenesis by modulating miR-181a maturation and subsequent hippocampal neural progenitor cell (NPC) lineages. Using NPCs cultured from PKCε or β-arrestin2 knockout mice and the MAPK/ERK kinase inhibitor U0126, we demonstrate that regulation of NPC differentiation via the miR-181a/Prox1/Notch1 pathway exhibits ligand-dependent selectivity. In NPCs, morphine and fentanyl activate ERK via the PKCε- and β-arrestin-dependent pathways, respectively. After fentanyl exposure, the activated phospho-ERK translocates to the nucleus. Conversely, after morphine treatment, phospho-ERK remains in the cytosol and is capable of phosphorylating TAR RNA-binding protein (TRBP), a cofactor of Dicer. This augments Dicer activity and promotes the maturation of miR-181a. Furthermore, using NPCs transfected with wild-type TRBP, SΔA, and SΔD TRBP mutants, we confirmed the crucial role of TRBP phosphorylation in Dicer activity, miR-181a maturation, and finally the morphine-induced astrocyte-preferential differentiation of NPCs. Thus, morphine modulates the lineage-specific differentiation of NPCs by PKCε-dependent ERK activation with subsequent TRBP phosphorylation and miR-181a maturation.
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Affiliation(s)
- Chi Xu
- Department of Pharmacology, University of Minnesota Medical School, Minneapolis, Minnesota, USA
| | - Hui Zheng
- Stem Cell and Cancer Biology Group, Key Laboratory of Regenerative Biology, South China Institute for Stem Cell Biology and Regenerative Medicine, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, People's Republic of China
| | - Horace H Loh
- Department of Pharmacology, University of Minnesota Medical School, Minneapolis, Minnesota, USA
| | - Ping-Yee Law
- Department of Pharmacology, University of Minnesota Medical School, Minneapolis, Minnesota, USA
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Fujita W, Gomes I, Devi LA. Revolution in GPCR signalling: opioid receptor heteromers as novel therapeutic targets: IUPHAR review 10. Br J Pharmacol 2015; 171:4155-76. [PMID: 24916280 DOI: 10.1111/bph.12798] [Citation(s) in RCA: 68] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2013] [Revised: 01/27/2014] [Accepted: 04/16/2014] [Indexed: 12/24/2022] Open
Abstract
GPCRs can interact with each other to form homomers or heteromers. Homomers involve interactions with the same receptor type while heteromers involve interactions between two different GPCRs. These receptor-receptor interactions modulate not only the binding but also the signalling and trafficking properties of individual receptors. Opioid receptor heteromerization has been extensively investigated with the objective of identifying novel therapeutic targets that are as potent as morphine but without the side effects associated with chronic morphine use. In this context, studies have described heteromerization between the different types of opioid receptors and between opioid receptors and a wide range of GPCRs including adrenoceptors, cannabinoid, 5-HT, metabotropic glutamate and sensory neuron-specific receptors. Recent advances in the field involving the generation of heteromer-specific reagents (antibodies or ligands) or of membrane-permeable peptides that disrupt the heteromer interaction are helping to elucidate the physiological role of opioid receptor heteromers and the contribution of the partner receptor to the side effects associated with opioid use. For example, studies using membrane-permeable peptides targeting the heteromer interface have implicated μ and δ receptor heteromers in the development of tolerance to morphine, and heteromers of μ and gastrin-releasing peptide receptors in morphine-induced itch. In addition, a number of ligands that selectively target opioid receptor heteromers exhibit potent antinociception with a decrease in the side effects commonly associated with morphine use. In this review, we summarize the latest findings regarding the biological and functional characteristics of opioid receptor heteromers both in vitro and in vivo.
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Affiliation(s)
- Wakako Fujita
- Department of Pharmacology and Systems Therapeutics, Icahn School of Medicine at Mount Sinai, New York, NY, USA
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Abstract
This paper is the thirty-sixth consecutive installment of the annual review of research concerning the endogenous opioid system. It summarizes papers published during 2013 that studied the behavioral effects of molecular, pharmacological and genetic manipulation of opioid peptides, opioid receptors, opioid agonists and opioid antagonists. The particular topics that continue to be covered include the molecular-biochemical effects and neurochemical localization studies of endogenous opioids and their receptors related to behavior, and the roles of these opioid peptides and receptors in pain and analgesia; stress and social status; tolerance and dependence; learning and memory; eating and drinking; alcohol and drugs of abuse; sexual activity and hormones, pregnancy, development and endocrinology; mental illness and mood; seizures and neurologic disorders; electrical-related activity and neurophysiology; general activity and locomotion; gastrointestinal, renal and hepatic functions; cardiovascular responses; respiration and thermoregulation; and immunological responses.
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Affiliation(s)
- Richard J Bodnar
- Department of Psychology and Neuropsychology Doctoral Sub-Program, Queens College, City University of New York, Flushing, NY 11367, United States.
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Schuster DJ, Metcalf MD, Kitto KF, Messing RO, Fairbanks CA, Wilcox GL. Ligand requirements for involvement of PKCε in synergistic analgesic interactions between spinal μ and δ opioid receptors. Br J Pharmacol 2014; 172:642-53. [PMID: 24827408 DOI: 10.1111/bph.12774] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2013] [Revised: 04/29/2014] [Accepted: 05/01/2014] [Indexed: 12/17/2022] Open
Abstract
BACKGROUND AND PURPOSE We recently found that PKCε was required for spinal analgesic synergy between two GPCRs, δ opioid receptors and α2 A adrenoceptors, co-located in the same cellular subpopulation. We sought to determine if co-delivery of μ and δ opioid receptor agonists would similarly result in synergy requiring PKCε. EXPERIMENTAL APPROACH Combinations of μ and δ opioid receptor agonists were co-administered intrathecally by direct lumbar puncture to PKCε-wild-type (PKCε-WT) and -knockout (PKCε-KO) mice. Antinociception was assessed using the hot-water tail-flick assay. Drug interactions were evaluated by isobolographic analysis. KEY RESULTS All agonists produced comparable antinociception in both PKCε-WT and PKCε-KO mice. Of 19 agonist combinations that produced analgesic synergy, only 3 required PKCε for a synergistic interaction. In these three combinations, one of the agonists was morphine, although not all combinations involving morphine required PKCε. Morphine + deltorphin II and morphine + deltorphin I required PKCε for synergy, whereas a similar combination, morphine + deltorphin, did not. Additionally, morphine + oxymorphindole required PKCε for synergy, whereas a similar combination, morphine + oxycodindole, did not. CONCLUSIONS AND IMPLICATIONS We discovered biased agonism for a specific signalling pathway at the level of spinally co-delivered opioid agonists. As the bias is only revealed by an appropriate ligand combination and cannot be accounted for by a single drug, it is likely that the receptors these agonists act on are interacting with each other. Our results support the existence of μ and δ opioid receptor heteromers at the spinal level in vivo. LINKED ARTICLES 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.
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Affiliation(s)
- D J Schuster
- Department of Neuroscience, Medical School, University of Minnesota, Minneapolis, MN, USA
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Aira Z, Barrenetxea T, Buesa I, Azkue JJ. Plasticity of α2-adrenergic spinal antinociception following nerve injury: selective, bidirectional interaction with the delta opioid receptor. Brain Res 2014; 1594:190-203. [PMID: 25446445 DOI: 10.1016/j.brainres.2014.11.009] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2014] [Revised: 11/04/2014] [Accepted: 11/06/2014] [Indexed: 11/25/2022]
Abstract
Interactions of opioid receptors with other receptor families can be made use of to improve analgesia and reduce adverse effects of opioid analgesics. We investigated interactions of the α2-adrenergic receptor (α2AR) with opioid receptors of the mu (MOR) and delta (DOR) types in the spinal dorsal horn in an animal model of neuropathic pain induced by spinal nerve ligation. Nine days after nerve injury, immunoreactivity for the α2AR subtype A (α2AAR) was increased both in tissue homogenates and at pre- and post-synaptic sites in transverse sections. The efficacy of spinally administered α2AAR agonist guanfacine at reducing C-fiber-evoked field potentials was increased in nerve-ligated rats. This reducing effect was impaired by simultaneous administration of DOR antagonist naltrindole, but not MOR antagonist CTOP, suggesting that concurrent DOR activation was required for α2AAR-mediated inhibition. While DOR agonist deltorphin II and MOR agonist DAMGO both effectively depressed C-fiber-evoked spinal field potentials, DOR- but not MOR-mediated depression was enhanced by subclinical guanfacine. In conscious, nerve-ligated rats, chronically administered deltorphin II produced stable thermal and mechanical antinociception over the 9 following days after nerve injury without apparent signs of habituation. Such an effect was dramatically enhanced by co-administration of a low dose of guanfacine, which reversed thermal and mechanical thresholds to levels near those prior to injury. The results suggest that spinal, α2AAR-mediated antinociception is increased after nerve injury and based on DOR co-activation. We demonstrate in vivo that α2AAR/DOR interaction can be exploited to provide effective behavioral antinociception during neuropathic pain.
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Affiliation(s)
- Zigor Aira
- Department of Neurosciences, School of Medicine and Dentistry, University of the Basque Country, PO Box 699, 48080 Bilbao, Spain
| | - Teresa Barrenetxea
- Department of Neurosciences, School of Medicine and Dentistry, University of the Basque Country, PO Box 699, 48080 Bilbao, Spain
| | - Itsaso Buesa
- Department of Neurosciences, School of Medicine and Dentistry, University of the Basque Country, PO Box 699, 48080 Bilbao, Spain
| | - Jon Jatsu Azkue
- Department of Neurosciences, School of Medicine and Dentistry, University of the Basque Country, PO Box 699, 48080 Bilbao, Spain.
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Zhang X, Bao L, Li S. Opioid receptor trafficking and interaction in nociceptors. Br J Pharmacol 2014; 172:364-74. [PMID: 24611685 DOI: 10.1111/bph.12653] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2013] [Revised: 01/29/2014] [Accepted: 02/17/2014] [Indexed: 01/15/2023] Open
Abstract
UNLABELLED Opiate analgesics such as morphine are often used for pain therapy. However, antinociceptive tolerance and dependence may develop with long-term use of these drugs. It was found that μ-opioid receptors can interact with δ-opioid receptors, and morphine antinociceptive tolerance can be reduced by blocking δ-opioid receptors. Recent studies have shown that μ- and δ-opioid receptors are co-expressed in a considerable number of small neurons in the dorsal root ganglion. The interaction of μ-opioid receptors with δ-opioid receptors in the nociceptive afferents is facilitated by the stimulus-induced cell-surface expression of δ-opioid receptors, and contributes to morphine tolerance. Further analysis of the molecular, cellular and neural circuit mechanisms that regulate the trafficking and interaction of opioid receptors and related signalling molecules in the pain pathway would help to elucidate the mechanism of opiate analgesia and improve pain therapy. LINKED ARTICLES 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.
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Affiliation(s)
- X Zhang
- Institute of Neuroscience and State Key Laboratory of Neuroscience, Shanghai, China
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Chabot-Doré AJ, Schuster DJ, Stone LS, Wilcox GL. Analgesic synergy between opioid and α2 -adrenoceptors. Br J Pharmacol 2014; 172:388-402. [PMID: 24641506 DOI: 10.1111/bph.12695] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2013] [Revised: 03/08/2014] [Accepted: 03/12/2014] [Indexed: 12/24/2022] Open
Abstract
UNLABELLED 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. LINKED ARTICLES 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.
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Affiliation(s)
- A-J Chabot-Doré
- Alan Edwards Centre for Research on Pain, McGill University, Montreal, QC, Canada; Department of Neurology and Neurosurgery, McGill University, Montreal, QC, Canada
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Gendron L, Mittal N, Beaudry H, Walwyn W. Recent advances on the δ opioid receptor: from trafficking to function. Br J Pharmacol 2014; 172:403-19. [PMID: 24665909 DOI: 10.1111/bph.12706] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2013] [Revised: 03/17/2014] [Accepted: 03/18/2014] [Indexed: 01/12/2023] Open
Abstract
UNLABELLED Within the opioid family of receptors, δ (DOPrs) and μ opioid receptors (MOPrs) are typical GPCRs that activate canonical second-messenger signalling cascades to influence diverse cellular functions in neuronal and non-neuronal cell types. These receptors activate well-known pathways to influence ion channel function and pathways such as the map kinase cascade, AC and PI3K. In addition new information regarding opioid receptor-interacting proteins, downstream signalling pathways and resultant functional effects has recently come to light. In this review, we will examine these novel findings focusing on the DOPr and, in doing so, will contrast and compare DOPrs with MOPrs in terms of differences and similarities in function, signalling pathways, distribution and interactions. We will also discuss and clarify issues that have recently surfaced regarding the expression and function of DOPrs in different cell types and analgesia. LINKED ARTICLES 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.
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Affiliation(s)
- Louis Gendron
- Département de physiologie et biophysique, Institut de pharmacologie de Sherbrooke, Faculté de médecine et des sciences de la santé, Université de Sherbrooke, Sherbrooke, QC, Canada
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