1
|
Qi Y, Nelson TS, Prasoon P, Norris C, Taylor BK. Contribution of µ Opioid Receptor-expressing Dorsal Horn Interneurons to Neuropathic Pain-like Behavior in Mice. Anesthesiology 2023; 139:840-857. [PMID: 37566700 PMCID: PMC10840648 DOI: 10.1097/aln.0000000000004735] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/13/2023]
Abstract
BACKGROUND Intersectional genetics have yielded tremendous advances in our understanding of molecularly identified subpopulations and circuits within the dorsal horn in neuropathic pain. The authors tested the hypothesis that spinal µ opioid receptor-expressing neurons (Oprm1-expressing neurons) contribute to behavioral hypersensitivity and neuronal sensitization in the spared nerve injury model in mice. METHODS The authors coupled the use of Oprm1Cre transgenic reporter mice with whole cell patch clamp electrophysiology in lumbar spinal cord slices to evaluate the neuronal activity of Oprm1-expressing neurons in the spared nerve injury model of neuropathic pain. The authors used a chemogenetic approach to activate or inhibit Oprm1-expressing neurons, followed by the assessment of behavioral signs of neuropathic pain. RESULTS The authors reveal that spared nerve injury yielded a robust neuroplasticity of Oprm1-expressing neurons. Spared nerve injury reduced Oprm1 gene expression in the dorsal horn as well as the responsiveness of Oprm1-expressing neurons to the selective µ agonist (D-Ala2, N-MePhe4, Gly-ol)-enkephalin (DAMGO). Spared nerve injury sensitized Oprm1-expressing neurons, as reflected by an increase in their intrinsic excitability (rheobase, sham 38.62 ± 25.87 pA [n = 29]; spared nerve injury, 18.33 ± 10.29 pA [n = 29], P = 0.0026) and spontaneous synaptic activity (spontaneous excitatory postsynaptic current frequency in delayed firing neurons: sham, 0.81 ± 0.67 Hz [n = 14]; spared nerve injury, 1.74 ± 1.68 Hz [n = 10], P = 0.0466), and light brush-induced coexpression of the immediate early gene product, Fos in laminae I to II (%Fos/tdTomato+: sham, 0.42 ± 0.57% [n = 3]; spared nerve injury, 28.26 ± 1.92% [n = 3], P = 0.0001). Chemogenetic activation of Oprm1-expressing neurons produced mechanical hypersensitivity in uninjured mice (saline, 2.91 ± 1.08 g [n = 6]; clozapine N-oxide, 0.65 ± 0.34 g [n = 6], P = 0.0006), while chemogenetic inhibition reduced behavioral signs of mechanical hypersensitivity (saline, 0.38 ± 0.37 g [n = 6]; clozapine N-oxide, 1.05 ± 0.42 g [n = 6], P = 0.0052) and cold hypersensitivity (saline, 6.89 ± 0.88 s [n = 5] vs. clozapine N-oxide, 2.31 ± 0.52 s [n = 5], P = 0.0017). CONCLUSIONS The authors conclude that nerve injury sensitizes pronociceptive µ opioid receptor-expressing neurons in mouse dorsal horn. Nonopioid strategies to inhibit these interneurons might yield new treatments for neuropathic pain. EDITOR’S PERSPECTIVE
Collapse
Affiliation(s)
- Yanmei Qi
- Department of Anesthesiology and Perioperative Medicine, Center for Neuroscience, Pittsburgh Center for Pain Research, Pittsburgh Project to end Opioid Misuse, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Tyler S. Nelson
- Department of Anesthesiology and Perioperative Medicine, Center for Neuroscience, Pittsburgh Center for Pain Research, Pittsburgh Project to end Opioid Misuse, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Pranav Prasoon
- Department of Anesthesiology and Perioperative Medicine, Center for Neuroscience, Pittsburgh Center for Pain Research, Pittsburgh Project to end Opioid Misuse, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Christopher Norris
- Department of Anesthesiology and Perioperative Medicine, Center for Neuroscience, Pittsburgh Center for Pain Research, Pittsburgh Project to end Opioid Misuse, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Bradley K. Taylor
- Department of Anesthesiology and Perioperative Medicine, Center for Neuroscience, Pittsburgh Center for Pain Research, Pittsburgh Project to end Opioid Misuse, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| |
Collapse
|
2
|
Zhang XY, Dou YN, Yuan L, Li Q, Zhu YJ, Wang M, Sun YG. Different neuronal populations mediate inflammatory pain analgesia by exogenous and endogenous opioids. eLife 2020; 9:55289. [PMID: 32519950 PMCID: PMC7311172 DOI: 10.7554/elife.55289] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2020] [Accepted: 06/10/2020] [Indexed: 02/06/2023] Open
Abstract
Mu-opioid receptors (MORs) are crucial for analgesia by both exogenous and endogenous opioids. However, the distinct mechanisms underlying these two types of opioid analgesia remain largely unknown. Here, we demonstrate that analgesic effects of exogenous and endogenous opioids on inflammatory pain are mediated by MORs expressed in distinct subpopulations of neurons in mice. We found that the exogenous opioid-induced analgesia of inflammatory pain is mediated by MORs in Vglut2+ glutamatergic but not GABAergic neurons. In contrast, analgesia by endogenous opioids is mediated by MORs in GABAergic rather than Vglut2+ glutamatergic neurons. Furthermore, MORs expressed at the spinal level is mainly involved in the analgesic effect of morphine in acute pain, but not in endogenous opioid analgesia during chronic inflammatory pain. Thus, our study revealed distinct mechanisms underlying analgesia by exogenous and endogenous opioids, and laid the foundation for further dissecting the circuit mechanism underlying opioid analgesia.
Collapse
Affiliation(s)
- Xin-Yan Zhang
- Institute of Neuroscience, State Key Laboratory of Neuroscience, CAS Center for Excellence in Brain Science & Intelligence Technology, Chinese Academy of Sciences, Shanghai, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Yan-Nong Dou
- Institute of Neuroscience, State Key Laboratory of Neuroscience, CAS Center for Excellence in Brain Science & Intelligence Technology, Chinese Academy of Sciences, Shanghai, China
| | - Lei Yuan
- Institute of Neuroscience, State Key Laboratory of Neuroscience, CAS Center for Excellence in Brain Science & Intelligence Technology, Chinese Academy of Sciences, Shanghai, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Qing Li
- Institute of Neuroscience, State Key Laboratory of Neuroscience, CAS Center for Excellence in Brain Science & Intelligence Technology, Chinese Academy of Sciences, Shanghai, China
| | - Yan-Jing Zhu
- Institute of Neuroscience, State Key Laboratory of Neuroscience, CAS Center for Excellence in Brain Science & Intelligence Technology, Chinese Academy of Sciences, Shanghai, China
| | - Meng Wang
- Institute of Neuroscience, State Key Laboratory of Neuroscience, CAS Center for Excellence in Brain Science & Intelligence Technology, Chinese Academy of Sciences, Shanghai, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Yan-Gang Sun
- Institute of Neuroscience, State Key Laboratory of Neuroscience, CAS Center for Excellence in Brain Science & Intelligence Technology, Chinese Academy of Sciences, Shanghai, China.,Shanghai Center for Brain Science and Brain-Inspired Intelligence Technology, Shanghai, China
| |
Collapse
|
3
|
Romero A, García-Carmona JA, Laorden ML, Puig MM. Role of CRF1 receptor in post-incisional plasma extravasation and nociceptive responses in mice. Toxicol Appl Pharmacol 2017; 332:121-128. [DOI: 10.1016/j.taap.2017.04.021] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2017] [Revised: 04/12/2017] [Accepted: 04/19/2017] [Indexed: 12/30/2022]
|
4
|
Accart N, Dawson J, Kolbinger F, Kramer I, Beckmann N. Non-invasive imaging demonstrates clinical features of ankylosing spondylitis in a rat adjuvant model: a case study. Eur J Histochem 2016; 60:2667. [PMID: 28076929 PMCID: PMC5134681 DOI: 10.4081/ejh.2016.2667] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2016] [Revised: 09/22/2016] [Accepted: 09/22/2016] [Indexed: 12/19/2022] Open
Abstract
Main features of ankylosing spondylitis like inflammatory erosive osteopenia and bony overgrowth are recapitulated in rats challenged with complete Freund’s adjuvant. In vivo changes induced in the rat spine were followed longitudinally by magnetic resonance imaging (MRI) and assessed terminally by micro-computerized tomography (micro-CT) and histology. Signals reflecting inflammation were detected by MRI at levels L5-L6 throughout the experiment, peaking at day 27 after adjuvant. Bone erosion and formation occurred from this time point onward, as confirmed by micro-CT. Histology confirmed the inflammation and bone remodeling. The present study demonstrates the potential of imaging for longitudinal assessments of spinal changes in this animal model and the excellent correlation between in vivo images and histology underlines its fundamental role in the validation of non-invasive imaging.
Collapse
Affiliation(s)
- N Accart
- Novartis Institute for Biomedical Research.
| | | | | | | | | |
Collapse
|
5
|
Tawfik DI, Osman AS, Tolba HM, Khattab A, Abdel-Salam LO, Kamel MM. Evaluation of therapeutic effect of low dose naltrexone in experimentally-induced Crohn's disease in rats. Neuropeptides 2016; 59:39-45. [PMID: 27392602 DOI: 10.1016/j.npep.2016.06.003] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/04/2016] [Revised: 06/17/2016] [Accepted: 06/20/2016] [Indexed: 12/25/2022]
Abstract
BACKGROUND AND AIM Crohn's disease is a relapsing inflammatory condition afflicting the digestive tract. Drugs used for treatment of Crohn's disease may be associated with serious side effects. Endogenous opioid peptides modulate inflammatory cytokine production. Opioid antagonists have been shown to play a role in healing and repair of tissues. This work was designed to detect the possible beneficial effects of opioid antagonist naltrexone in indomethacin-induced Crohn's disease in rats. EXPERIMENTAL APPROACH Enteritis was induced in male albino rats by two subcutaneous injection of indomethacin in a dose of 7.5mg/kg 24h apart started on day one. Salfasalazine, naltrexone and their combination were administered orally from day one of induction of enteritis to day 10. Disease activity index, serum levels of C-reactive protein and tumor necrosis factor-α, macroscopic and microscopic pathological scores and in vitro motility studies were evaluated. RESULTS Induction of enteritis resulted in significant increase of disease activity index, significant elevation of serum levels of C-reactive protein and tumor necrosis factor-α, significant deterioration of pathological scores and significant increase in the mean contractility response of the isolated ileal segments compared with normal untreated rats. Treatment with sulfasalazine, low dose of natrexone or their combination resulted in significant improvement of all measured parameters compared with enteritis group. CONCLUSION The current finding could provide new interesting opportunity for developing new therapeutic approaches for treatment of Crohn's disease. Use of naltrexone, especially in small dose, has little side effects making it of interest for treatment of Crohn's disease. Also, it provides the possibility of reduced doses of other drugs if it is used as combined therapy.
Collapse
Affiliation(s)
| | - Afaf Sayed Osman
- Medical Pharmacology Department, Faculty of Medicine, Cairo University, Eqypt.
| | | | - Aida Khattab
- Medical Pharmacology Department, Faculty of Medicine, Cairo University, Eqypt
| | | | - Mahmoud M Kamel
- Clinical Pathology Department, National Cancer Institute, Cairo University, Egypt
| |
Collapse
|
6
|
Akgün E, Javed MI, Lunzer MM, Powers MD, Sham YY, Watanabe Y, Portoghese PS. Inhibition of Inflammatory and Neuropathic Pain by Targeting a Mu Opioid Receptor/Chemokine Receptor5 Heteromer (MOR-CCR5). J Med Chem 2015; 58:8647-57. [PMID: 26451468 DOI: 10.1021/acs.jmedchem.5b01245] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Chemokine release promotes cross-talk between opioid and chemokine receptors that in part leads to reduced efficacy of morphine in the treatment of chronic pain. On the basis of the possibility that a MOR-CCR5 heteromer is involved in such cross-talk, we have synthesized bivalent ligands (MCC series) that contain mu opioid agonist and CCR5 antagonist pharmacophores linked through homologous spacers (14-24 atoms). When tested on lipopolysaccharide-inflamed mice, a member of the series (MCC22; 3e) with a 22-atom spacer exhibited profound antinociception (i.t. ED50 = 0.0146 pmol/mouse) that was 2000× greater than morphine. Moreover, MCC22 was ~3500× more potent than a mixture of mu agonist and CCR5 antagonist monovalent ligands. These data strongly suggest that MCC22 acts by bridging the protomers of a MOR-CCR5 heteromer having a TM5,6 interface. Molecular simulation studies are consistent with such bridging. This study supports the MOR-CCR5 heteromer as a novel target for the treatment of chronic pain.
Collapse
Affiliation(s)
- Eyup Akgün
- Department of Medicinal Chemistry, and ‡Center for Drug Design, University of Minnesota , Minneapolis, Minnesota 55455, United States
| | - Muhammad I Javed
- Department of Medicinal Chemistry, and ‡Center for Drug Design, University of Minnesota , Minneapolis, Minnesota 55455, United States
| | - Mary M Lunzer
- Department of Medicinal Chemistry, and ‡Center for Drug Design, University of Minnesota , Minneapolis, Minnesota 55455, United States
| | - Michael D Powers
- Department of Medicinal Chemistry, and ‡Center for Drug Design, University of Minnesota , Minneapolis, Minnesota 55455, United States
| | - Yuk Y Sham
- Department of Medicinal Chemistry, and ‡Center for Drug Design, University of Minnesota , Minneapolis, Minnesota 55455, United States
| | - Yoshikazu Watanabe
- Department of Medicinal Chemistry, and ‡Center for Drug Design, University of Minnesota , Minneapolis, Minnesota 55455, United States
| | - Philip S Portoghese
- Department of Medicinal Chemistry, and ‡Center for Drug Design, University of Minnesota , Minneapolis, Minnesota 55455, United States
| |
Collapse
|
7
|
Weibel R, Reiss D, Karchewski L, Gardon O, Matifas A, Filliol D, Becker JAJ, Wood JN, Kieffer BL, Gaveriaux-Ruff C. Mu opioid receptors on primary afferent nav1.8 neurons contribute to opiate-induced analgesia: insight from conditional knockout mice. PLoS One 2013; 8:e74706. [PMID: 24069332 PMCID: PMC3771900 DOI: 10.1371/journal.pone.0074706] [Citation(s) in RCA: 93] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2013] [Accepted: 08/05/2013] [Indexed: 12/26/2022] Open
Abstract
Opiates are powerful drugs to treat severe pain, and act via mu opioid receptors distributed throughout the nervous system. Their clinical use is hampered by centrally-mediated adverse effects, including nausea or respiratory depression. Here we used a genetic approach to investigate the potential of peripheral mu opioid receptors as targets for pain treatment. We generated conditional knockout (cKO) mice in which mu opioid receptors are deleted specifically in primary afferent Nav1.8-positive neurons. Mutant animals were compared to controls for acute nociception, inflammatory pain, opiate-induced analgesia and constipation. There was a 76% decrease of mu receptor-positive neurons and a 60% reduction of mu-receptor mRNA in dorsal root ganglia of cKO mice. Mutant mice showed normal responses to heat, mechanical, visceral and chemical stimuli, as well as unchanged morphine antinociception and tolerance to antinociception in models of acute pain. Inflammatory pain developed similarly in cKO and controls mice after Complete Freund's Adjuvant. In the inflammation model, however, opiate-induced (morphine, fentanyl and loperamide) analgesia was reduced in mutant mice as compared to controls, and abolished at low doses. Morphine-induced constipation remained intact in cKO mice. We therefore genetically demonstrate for the first time that mu opioid receptors partly mediate opiate analgesia at the level of Nav1.8-positive sensory neurons. In our study, this mechanism operates under conditions of inflammatory pain, but not nociception. Previous pharmacology suggests that peripheral opiates may be clinically useful, and our data further demonstrate that Nav1.8 neuron-associated mu opioid receptors are feasible targets to alleviate some forms of persistent pain.
Collapse
Affiliation(s)
- Raphaël Weibel
- IGBMC Institut de Génétique et de Biologie Moléculaire et Cellulaire, Translational Medicine and Neurogenetic Programme, UdS Université de Strasbourg, INSERM U964, CNRS UMR7104, Illkirch, France
| | - David Reiss
- IGBMC Institut de Génétique et de Biologie Moléculaire et Cellulaire, Translational Medicine and Neurogenetic Programme, UdS Université de Strasbourg, INSERM U964, CNRS UMR7104, Illkirch, France
| | - Laurie Karchewski
- IGBMC Institut de Génétique et de Biologie Moléculaire et Cellulaire, Translational Medicine and Neurogenetic Programme, UdS Université de Strasbourg, INSERM U964, CNRS UMR7104, Illkirch, France
| | - Olivier Gardon
- IGBMC Institut de Génétique et de Biologie Moléculaire et Cellulaire, Translational Medicine and Neurogenetic Programme, UdS Université de Strasbourg, INSERM U964, CNRS UMR7104, Illkirch, France
| | - Audrey Matifas
- IGBMC Institut de Génétique et de Biologie Moléculaire et Cellulaire, Translational Medicine and Neurogenetic Programme, UdS Université de Strasbourg, INSERM U964, CNRS UMR7104, Illkirch, France
| | - Dominique Filliol
- IGBMC Institut de Génétique et de Biologie Moléculaire et Cellulaire, Translational Medicine and Neurogenetic Programme, UdS Université de Strasbourg, INSERM U964, CNRS UMR7104, Illkirch, France
| | - Jérôme A. J. Becker
- IGBMC Institut de Génétique et de Biologie Moléculaire et Cellulaire, Translational Medicine and Neurogenetic Programme, UdS Université de Strasbourg, INSERM U964, CNRS UMR7104, Illkirch, France
| | - John N. Wood
- Molecular Nociception Group, Wolfson Institute for Biomedical research, University College London, London, United Kingdom
| | - Brigitte L. Kieffer
- IGBMC Institut de Génétique et de Biologie Moléculaire et Cellulaire, Translational Medicine and Neurogenetic Programme, UdS Université de Strasbourg, INSERM U964, CNRS UMR7104, Illkirch, France
| | - Claire Gaveriaux-Ruff
- IGBMC Institut de Génétique et de Biologie Moléculaire et Cellulaire, Translational Medicine and Neurogenetic Programme, UdS Université de Strasbourg, INSERM U964, CNRS UMR7104, Illkirch, France
- ESBS, École Supérieure de Biotechnologie de Strasbourg, UdS Université de Strasbourg, Strasbourg, France
- * E-mail:
| |
Collapse
|
8
|
Ligands that interact with putative MOR-mGluR5 heteromer in mice with inflammatory pain produce potent antinociception. Proc Natl Acad Sci U S A 2013; 110:11595-9. [PMID: 23798416 DOI: 10.1073/pnas.1305461110] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The low effectiveness of morphine and related mu opioid analgesics for the treatment of chronic inflammatory pain is a result of opioid-induced release of proinflammatory cytokines and glutamate that lower the pain threshold. In this regard, the use of opioids with metabotropic glutamate-5 receptor (mGluR5) antagonist has been reported to increase the efficacy of morphine and prevent the establishment of adverse effects during chronic use. Given the presence of opioid receptors (MORs) and mGluR5 in glia and neurons, together with reports that suggest coexpressed MOR/mGluR5 receptors in cultured cells associate as a heteromer, the possibility that such a heteromer could be a target in vivo was addressed by the design and synthesis of a series of bivalent ligands that contain mu opioid agonist and mGluR5 antagonist pharmacophores linked through spacers of varying length (10-24 atoms). The series was evaluated for antinociception using the tail-flick and von Frey assays in mice pretreated with lipopolysaccharide (LPS) or in mice with bone cancer. In LPS-pretreated mice, MMG22 (4c, 22-atom spacer) was the most potent member of the series (intrathecal ED50 ∼9 fmol per mouse), whereas in untreated mice its ED50 was more than three orders of magnitude higher. As members of the series with shorter or longer spacers have ≥500-fold higher ED50s in LPS-treated mice, the exceptional potency of MMG22 may be a result of the optimal bridging of protomers in a putative MOR-mGluR5 heteromer. The finding that MMG22 possesses a >10(6) therapeutic ratio suggests that it may be an excellent candidate for treatment of chronic, intractable pain via spinal administration.
Collapse
|
9
|
Abstract
BACKGROUND Neutrophils are one of the predominant immune cells initially migrating to surgical wound edges. They produce mediators both associated with supporting (interleukin [IL]-1β, C5a) and reducing (opioid peptides) pain. Studies demonstrate neutrophil depletion/blockade reduces nociceptive sensitization after nerve injury and carrageenan administration, but enhance sensitization in complete Freund's adjuvant inflammation. This research identifies the contribution of infiltrating neutrophils to incisional pain and inflammation. METHODS Antibody-mediated Gr1 neutrophil depletion preceded hind paw incisions. Sensitization to mechanical and thermal stimuli, effects on edema and local levels of IL-1β and C5a were measured. Local effects of C5a or IL-1 receptor antagonists PMX-53 and anakinra on sensitization after neutrophil depletion were examined. Groups of 4-8 mice were used. RESULTS Anti-Gr1 antibody depleted more than 90% of circulating and infiltrating skin neutrophils after incision. Neutrophil depletion did not change magnitude or duration of mechanical hypersensitivity in incised mice. However, paw edema was significantly reduced and heat hypersensitivity was slightly increased in depleted animals. In depleted animals IL-1β levels were half of controls 24 h after incision, whereas C5a levels were increased in both. Prominent IL-1β immunohistochemical staining of epidermis was seen in both groups. PMX-53 and anakinra reduced incisional mechanical and heat nociceptive sensitization to the same extent, regardless of neutrophil depletion. CONCLUSIONS Neutrophil-derived IL-1β and C5a do not appear to contribute critically to peri-incisional nociceptive signaling. Other sources of mediators, such as epidermal cells, may need to be considered. Controlling inflammatory activation of resident cells in epidermis/deeper structures may show therapeutic efficacy in reducing pain from surgical incisions.
Collapse
|
10
|
Inhibiting the breakdown of endogenous opioids and cannabinoids to alleviate pain. Nat Rev Drug Discov 2012; 11:292-310. [DOI: 10.1038/nrd3673] [Citation(s) in RCA: 139] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
|
11
|
Su TF, Zhang LH, Peng M, Wu CH, Pan W, Tian B, Shi J, Pan HL, Li M. Cannabinoid CB2 receptors contribute to upregulation of β-endorphin in inflamed skin tissues by electroacupuncture. Mol Pain 2011; 7:98. [PMID: 22177137 PMCID: PMC3281798 DOI: 10.1186/1744-8069-7-98] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2011] [Accepted: 12/19/2011] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Electroacupuncture (EA) can produce analgesia by increasing the β-endorphin level and activation of peripheral μ-opioid receptors in inflamed tissues. Endogenous cannabinoids and peripheral cannabinoid CB2 receptors (CB2Rs) are also involved in the antinociceptive effect of EA on inflammatory pain. However, little is known about how peripheral CB2Rs interact with the endogenous opioid system at the inflammatory site and how this interaction contributes to the antinociceptive effect of EA on inflammatory pain. In this study, we determined the role of peripheral CB2Rs in the effects of EA on the expression of β-endorphin in inflamed skin tissues and inflammatory pain. RESULTS Inflammatory pain was induced by injection of complete Freund's adjuvant into the left hindpaw of rats. Thermal hyperalgesia was tested with a radiant heat stimulus, and mechanical allodynia was quantified using von Frey filaments. The mRNA level of POMC and protein level of β-endorphin were quantified by real-time PCR and Western blotting, respectively. The β-endorphin-containing keratinocytes and immune cells in the inflamed skin tissues were detected by double-immunofluorescence labeling. The CB2R agonist AM1241 or EA significantly reduced thermal hyperalgesia and mechanical allodynia, whereas the selective μ-opioid receptor antagonist β-funaltrexamine significantly attenuated the antinociceptive effect produced by them. AM1241 or EA significantly increased the mRNA level of POMC and the protein level of β-endorphin in inflamed skin tissues, and these effects were significantly attenuated by pretreatment with the CB2R antagonist AM630. AM1241 or EA also significantly increased the percentage of β-endorphin-immunoreactive keratinocytes, macrophages, and T-lymphocytes in inflamed skin tissues, and these effects were blocked by AM630. CONCLUSIONS EA and CB2R stimulation reduce inflammatory pain through activation of μ-opioid receptors. EA increases endogenous opioid expression in keratinocytes and infiltrating immune cells at the inflammatory site through CB2R activation.
Collapse
Affiliation(s)
- Tang-feng Su
- Department of Neurobiology, Tongji Medical College of Huazhong University of Science and Technology, 13 Hangkong Road, Wuhan, 430030, PR China
| | | | | | | | | | | | | | | | | |
Collapse
|
12
|
Stein C, Machelska H. Modulation of Peripheral Sensory Neurons by the Immune System: Implications for Pain Therapy. Pharmacol Rev 2011; 63:860-81. [DOI: 10.1124/pr.110.003145] [Citation(s) in RCA: 133] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
|
13
|
Opioid receptors and opioid peptide-producing leukocytes in inflammatory pain--basic and therapeutic aspects. Brain Behav Immun 2010; 24:683-94. [PMID: 19879349 DOI: 10.1016/j.bbi.2009.10.013] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/06/2009] [Revised: 10/22/2009] [Accepted: 10/24/2009] [Indexed: 12/12/2022] Open
Abstract
This review summarizes recent findings on neuro-immune mechanisms underlying opioid-mediated inhibition of pain. The focus is on events occurring in peripheral injured tissues that lead to the sensitization and excitation of primary afferent neurons, and on the modulation of such mechanisms by immune cell-derived opioid peptides. Primary afferent neurons are of particular interest from a therapeutic perspective because they are the initial generators of impulses relaying nociceptive information towards the spinal cord and the brain. Thus, if one finds ways to inhibit the sensitization and/or excitation of peripheral sensory neurons, subsequent central events such as wind-up, sensitization and plasticity may be prevented. This is in part achieved by endogenously released immune cell-derived opioid peptides within inflamed tissue. In addition, exogenous opioid receptor ligands that selectively modulate primary afferent function and do not cross the blood-brain barrier, avoid centrally mediated untoward side effects of conventional analgesics (e.g., opioids, anticonvulsants). This article discusses peripheral opioid receptors and their signaling pathways, opioid peptide-producing/secreting inflammatory cells and arising therapeutic perspectives.
Collapse
|
14
|
Pain-related behaviors and neurochemical alterations in mice expressing sickle hemoglobin: modulation by cannabinoids. Blood 2010; 116:456-65. [PMID: 20304807 DOI: 10.1182/blood-2010-01-260372] [Citation(s) in RCA: 139] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Sickle cell disease causes severe pain. We examined pain-related behaviors, correlative neurochemical changes, and analgesic effects of morphine and cannabinoids in transgenic mice expressing human sickle hemoglobin (HbS). Paw withdrawal threshold and withdrawal latency (to mechanical and thermal stimuli, respectively) and grip force were lower in homozygous and hemizygous Berkley mice (BERK and hBERK1, respectively) compared with control mice expressing human hemoglobin A (HbA-BERK), indicating deep/musculoskeletal and cutaneous hyperalgesia. Peripheral nerves and blood vessels were structurally altered in BERK and hBERK1 skin, with decreased expression of mu opioid receptor and increased calcitonin gene-related peptide and substance P immunoreactivity. Activators of neuropathic and inflammatory pain (p38 mitogen-activated protein kinase, STAT3, and mitogen-activated protein kinase/extracellular signal-regulated kinase) showed increased phosphorylation, with accompanying increase in COX-2, interleukin-6, and Toll-like receptor 4 in the spinal cord of hBERK1 compared with HbA-BERK. These neurochemical changes in the periphery and spinal cord may contribute to hyperalgesia in mice expressing HbS. In BERK and hBERK1, hyperalgesia was markedly attenuated by morphine and cannabinoid receptor agonist CP 55940. We show that mice expressing HbS exhibit characteristics of pain observed in sickle cell disease patients, and neurochemical changes suggestive of nociceptor and glial activation. Importantly, cannabinoids attenuate pain in mice expressing HbS.
Collapse
|
15
|
Transfection of rat cells with proopiomeranocortin gene, precursor of endogenous endorphin, using radial shock waves suppresses inflammatory pain. Spine (Phila Pa 1976) 2009; 34:2270-7. [PMID: 19934807 DOI: 10.1097/brs.0b013e3181af77b4] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
STUDY DESIGN The effect of proopiomelanocortin (POMC) gene transfer with radial shock waves (RSW) was investigated in vitro and in vivo rat pain models. OBJECTIVE To examine the efficacy of POMC gene transfer with RSW, efficiency of beta-endorphin production in transfected cells, and its effects and side effects in pain models. SUMMARY OF BACKGROUND DATA Opioids have been used to treat chronic pain originating from knee osteoarthritis and the lower back; however, several side effects have been reported. Endogenous opioids are safe, but they are not used for clinical treatment because their metabolism is very fast. METHODS POMC plasmid was produced from pretransformed rat brain cDNA. POMC gene was added to the muscle of rat in vitro and in vivo with RSWs. We assessed beta-endorphin activity using immunohistochemistry. For assessment of pain behavior, we evaluated change in pain score and the level of the inflammatory neuropeptide, calcitonin gene-related peptide (CGRP), after transfection of the POMC gene in an adjuvant induced pain model for 28 days after treatment. RESULTS POMC transfected using RSW expressed beta-endorphin at a significantly increased level in muscle cells compared with non-RSW transfection and controls in vitro and in vivo (P < 0.05).Animals showed significant pain sensitivity and increased CGRP expression in dorsal root ganglia neurons in this model; however, these findings decreased for 14 days after transfection of POMC into muscle. There was no significant difference in side effects, such as a change in the level of food pellet intake or constipation, between POMC-treated animals and untreated animals. CONCLUSION POMC transfection with RSW increased beta-endorphin expression in muscle for 14 days, and suppressed pain behavior and CGRP expression in dorsal root ganglia neurons without side effects. This suggested that transfer of POMC by RSW is an effective treatment for inflammatory pain.
Collapse
|
16
|
Abstract
This chapter reviews the expression and regulation of opioid receptors in sensory neurons and the interactions of these receptors with endogenous and exogenous opioid ligands. Inflammation of peripheral tissues leads to increased synthesis and axonal transport of opioid receptors in dorsal root ganglion neurons. This results in opioid receptor upregulation and enhanced G protein coupling at peripheral sensory nerve terminals. These events are dependent on neuronal electrical activity, and on production of proinflammatory cytokines and nerve growth factor within the inflamed tissue. Together with the disruption of the perineurial barrier, these factors lead to an enhanced analgesic efficacy of peripherally active opioids. The major local source of endogenous opioid ligands (e.g. beta-endorphin) is leukocytes. These cells contain and upregulate signal-sequence-encoding messenger RNA of the beta-endorphin precursor proopiomelanocortin and the entire enzymatic machinery necessary for its processing into the functionally active peptide. Opioid-containing immune cells extravasate using adhesion molecules and chemokines to accumulate in inflamed tissues. Upon stressful stimuli or in response to releasing agents such as corticotropin-releasing factor, cytokines, chemokines, and catecholamines, leukocytes secrete opioids. Depending on the cell type, this release is contingent on extracellular Ca(2+) or on inositol triphosphate receptor triggered release of Ca(2+) from endoplasmic reticulum. Once secreted, opioid peptides activate peripheral opioid receptors and produce analgesia by inhibiting the excitability of sensory nerves and/or the release of proinflammatory neuropeptides. These effects occur without central untoward side effects such as depression of breathing, clouding of consciousness, or addiction. Future aims include the development of peripherally restricted opioid agonists, selective targeting of opioid-containing leukocytes to sites of painful injury, and the augmentation of peripheral opioid peptide and receptor synthesis.
Collapse
Affiliation(s)
- Christoph Stein
- Klinik für Anaesthesiologie und operative Intensivmedizin, Freie Universität Berlin, Charité - Campus Benjamin Franklin, 12200 Berlin, Germany.
| | | |
Collapse
|
17
|
Stein C, Clark JD, Oh U, Vasko MR, Wilcox GL, Overland AC, Vanderah TW, Spencer RH. Peripheral mechanisms of pain and analgesia. ACTA ACUST UNITED AC 2008; 60:90-113. [PMID: 19150465 DOI: 10.1016/j.brainresrev.2008.12.017] [Citation(s) in RCA: 184] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/29/2008] [Indexed: 12/23/2022]
Abstract
This review summarizes recent findings on peripheral mechanisms underlying the generation and inhibition of pain. The focus is on events occurring in peripheral injured tissues that lead to the sensitization and excitation of primary afferent neurons, and on the modulation of such mechanisms. Primary afferent neurons are of particular interest from a therapeutic perspective because they are the initial generator of noxious impulses traveling towards relay stations in the spinal cord and the brain. Thus, if one finds ways to inhibit the sensitization and/or excitation of peripheral sensory neurons, subsequent central events such as wind-up, sensitization and plasticity may be prevented. Most importantly, if agents are found that selectively modulate primary afferent function and do not cross the blood-brain-barrier, centrally mediated untoward side effects of conventional analgesics (e.g. opioids, anticonvulsants) may be avoided. This article begins with the peripheral actions of opioids, turns to a discussion of the effects of adrenergic co-adjuvants, and then moves on to a discussion of pro-inflammatory mechanisms focusing on TRP channels and nerve growth factor, their signaling pathways and arising therapeutic perspectives.
Collapse
Affiliation(s)
- Christoph Stein
- Department of Anesthesiology and Critical Care Medicine, Charité Campus Benjamin Franklin, Freie Universität Berlin, Germany
| | | | | | | | | | | | | | | |
Collapse
|
18
|
Börzsei R, Pozsgai G, Bagoly T, Elekes K, Pintér E, Szolcsányi J, Helyes Z. Inhibitory action of endomorphin-1 on sensory neuropeptide release and neurogenic inflammation in rats and mice. Neuroscience 2008; 152:82-8. [PMID: 18248905 DOI: 10.1016/j.neuroscience.2007.12.005] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2007] [Revised: 11/27/2007] [Accepted: 12/04/2007] [Indexed: 10/22/2022]
Abstract
Substance P (SP) and calcitonin gene-related peptide (CGRP) released from capsaicin-sensitive sensory nerves induce local neurogenic inflammation in the innervated area. The aim of the present study was to investigate the effects of an endogenous opioid peptide, endomorphin-1, on sensory neuropeptide release in vitro and acute neurogenic and non-neurogenic inflammatory reactions in vivo. Electrical field stimulation (EFS; 40 V, 0.1 ms, 10 Hz, 120 s; 1200 impulses) was performed to evoke SP and CGRP release from peptidergic afferents of the isolated rat tracheae which was determined from the incubation medium with radioimmunoassay. Neurogenic inflammation in the skin of the acutely denervated rat hind paw was induced by topical application of 1% mustard oil and detected by Evans Blue leakage. Mustard oil-induced ear swelling of the mouse was determined with a micrometer during 3 h and myeloperoxidase activity as an indicator of granulocyte accumulation was measured with spectrophotometry at 6 h. EFS evoked about a twofold elevation in the release of both pro-inflammatory sensory neuropeptides. Endomorphin-1 (5 nM-2 microM) diminished the release of SP and CGRP in a concentration-dependent manner, the EC50 values were 39.45 nM and 10.84 nM, respectively. The maximal inhibitory action was about 80% in both cases. Administration of endomorphin-1 (1-100 microg/kg i.p.) dose-dependently inhibited mustard oil-evoked neurogenic plasma protein extravasation in the rat skin as determined by microg Evans Blue per g wet tissue. Repeated i.p. injections of the 10 microg/kg dose three times per day for 10 days did not induce desensitization in this model. Neurogenic swelling of the mouse ear was also dose-dependently diminished by 1-100 microg/kg i.p. endomorphin-1, but non-neurogenic neutrophil accumulation was not influenced. These results suggest that endomorphin-1 is able to inhibit the outflow of pro-inflammatory sensory neuropeptides. Based on this mechanism of action it is also able to effectively diminish neurogenic inflammatory responses in vivo.
Collapse
Affiliation(s)
- R Börzsei
- Department of Pharmacology and Pharmacotherapy, Faculty of Medicine, University of Pécs, H-7643, Pécs, Szigeti u. 12, Hungary
| | | | | | | | | | | | | |
Collapse
|
19
|
Cho WG, Valtschanoff JG. Vanilloid receptor TRPV1-positive sensory afferents in the mouse ankle and knee joints. Brain Res 2008; 1219:59-65. [PMID: 18538749 DOI: 10.1016/j.brainres.2008.04.043] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2008] [Revised: 04/08/2008] [Accepted: 04/08/2008] [Indexed: 12/11/2022]
Abstract
TRPV1, a cation channel on sensory nerves sensitive to heat and capsaicin, plays an important role in the transduction of noxious stimuli to the spinal cord. It is expressed by neurons in dorsal root ganglia (DRG) that may also express neuropeptides, which are important for the development of inflammation. Mice with genetic deletion of TRPV1 have been used to study the involvement of this receptor in the mediation of pain and inflammation in animal models of arthritis. However, the expression of TRPV1 in the mouse articular afferents has not been studied. We here provide numerical data on expression of TRPV1 in an identified population of sensory afferents to the mouse L3-L5 DRG that innervate joints, in comparison with that from bladder and skin. A combination of tracing and immunohistochemistry revealed that TRPV1-positive fibers innervate the mouse knee and ankle. At the level of DRG, approximately 40% of articular afferents from these joints express TRPV1 and the majority of them are peptidergic, as revealed by simultaneous immunostaining for the neuropeptide calcitonin gene-related peptide. These findings are consistent with the idea that activation of TRPV1 in peripheral axons of joint afferents may mediate the synovial release of neuropeptides in arthritis.
Collapse
Affiliation(s)
- Won Gil Cho
- Department of Opthalmology and Visual Sciences, University of Kentucky, Lexington, Kentucky 40536, USA
| | | |
Collapse
|
20
|
Lynch JL, Alley JF, Wellman L, Beitz AJ. Decreased spinal cord opioid receptor mRNA expression and antinociception in a Theiler's murine encephalomyelitis virus model of multiple sclerosis. Brain Res 2007; 1191:180-91. [PMID: 18096140 DOI: 10.1016/j.brainres.2007.11.034] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2007] [Revised: 11/15/2007] [Accepted: 11/17/2007] [Indexed: 01/24/2023]
Abstract
Multiple sclerosis patients typically experience increased pain that is relatively insensitive to opiate treatment. The mechanistic basis for this increased nociception is currently poorly understood. In the present study, we utilized the Theiler's murine encephalomyelitis virus (TMEV) model of MS to examine possible changes in spinal cord opioid receptor mRNA over the course of disease progression. TMEV infection led to significantly decreased mu, delta and kappa opioid receptor mRNA expression as analyzed by quantitative real-time PCR in both male and female mice at days 90, 150 and 180 post-infection (PI). Since opioid receptor mRNA expression decreased in TMEV mice, we examined whether opiate analgesia is also altered. TMEV infected female mice had significantly decreased opiate analgesia in thermal nociceptive tests beginning at day 90 PI, while TMEV-infected male mice did not display significantly decreased opiate analgesia until day 120 PI. The novel finding that opioid receptor expression is significantly decreased in the spinal cord of TMEV mice could explain the increased nociception and loss of opiate analgesia observed in both TMEV mice and multiple sclerosis patients.
Collapse
Affiliation(s)
- Jessica L Lynch
- Department of Veterinary and Biomedical Sciences, University of Minnesota, 1988 Fitch Avenue, St. Paul, MN 55108, USA
| | | | | | | |
Collapse
|
21
|
Fernández-Dueñas V, Pol O, García-Nogales P, Hernández L, Planas E, Puig MM. Tolerance to the Antinociceptive and Antiexudative Effects of Morphine in a Murine Model of Peripheral Inflammation. J Pharmacol Exp Ther 2007; 322:360-8. [PMID: 17468301 DOI: 10.1124/jpet.106.118901] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Opioids are used in humans in the management of chronic osteoarticular pains, but the development of tolerance to the analgesic effects after continuous administration is still not well understood. Our aim was to characterize morphine tolerance in a murine model of arthritis that mimics the sequence of events occurring in humans. Inflammation was induced by the intraplantar injection of complete Freund's adjuvant (CFA) and tolerance by the implantation of a 75-mg morphine pellet. We assessed the antihyperalgesic (plantar and Randall-Selitto tests), antiallodynic (Von Frey test), and antiexudative (Evans blue) effects of morphine, the mu-opioid receptor (MOR) mRNA levels in dorsal root ganglia (DRG), and MOR protein levels in DRG and plantar tissue. Inflammation induced plasma extravasation, and it significantly increased the antihyperalgesic effects of morphine (p < 0.05). Morphine pellet implantation decreased morphine potency in all tests. ED(50) values decreased 4.4 and 7.3 times in the absence and presence of inflammation in the plantar test and 2.7 and 5.3 times in the Randall-Selitto test, whereas plasma extravasation decreased 4.2 times. MOR mRNA levels in the DRG were not affected 7 days after inflammation, whereas chronic morphine administration induced a discrete increase (p < 0.05). MOR protein in the DRG or the paw was unchanged. The results show that inflammation enhances the development of tolerance to the antihyperalgesic and antiexudative effects of morphine. At the molecular level, our results suggest that these effects are not mediated by changes in MOR expression but by other changes in receptor activation/internalization.
Collapse
Affiliation(s)
- Víctor Fernández-Dueñas
- Department of Anesthesiology, UAB, Hospital del Mar, Paseo Marítimo 25, 08003 Barcelona, Spain
| | | | | | | | | | | |
Collapse
|
22
|
Mousa SA, Straub RH, Schäfer M, Stein C. Beta-endorphin, Met-enkephalin and corresponding opioid receptors within synovium of patients with joint trauma, osteoarthritis and rheumatoid arthritis. Ann Rheum Dis 2007; 66:871-9. [PMID: 17324971 PMCID: PMC1955126 DOI: 10.1136/ard.2006.067066] [Citation(s) in RCA: 98] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
OBJECTIVE Intra-articularly applied opioid agonists or antagonists modulate pain after knee surgery and in chronic arthritis. Therefore, the expression of beta-endorphin (END), Met-enkephalin (ENK), and mu and delta opioid receptors (ORs) within synovium of patients with joint trauma (JT), osteoarthritis (OA) and rheumatoid arthritis (RA) were examined. METHODS Synovial samples were subjected to double immunohistochemical analysis of opioid peptides with immune cell markers, and of ORs with the neuronal markers calcitonin gene-related peptide (CGRP) and tyrosine hydroxylase (TH). RESULTS END and ENK were expressed by macrophage-like (CD68(+)) and fibroblast-like (CD68(-)) cells within synovial lining layers of all disorders. In the sublining layers, END and ENK were mostly expressed by granulocytes in patients with JT, and by macrophages/monocytes, lymphocytes and plasma cells in those with OA and RA. Overall, END- and ENK-immunoreactive (IR) cells were more abundant in patients with RA than in those with OA and JT. ORs were found on nerve fibres and immune cells in all patients. OR-IR nerve fibres were significantly more abundant in patients with RA than in those with OA and JT. muORs and deltaORs were coexpressed with CGRP but not with TH. CONCLUSIONS Parallel to the severity of inflammation, END and ENK in immune cells and their receptors on sensory nerve terminals are more abundant in patients with RA than in those with JT and OA. These findings are consistent with the notion that, with prolonged and enhanced inflammation, the immune and peripheral nervous systems upregulate sensory nerves expressing ORs and their ligands to counterbalance pain and inflammation.
Collapse
Affiliation(s)
- Shaaban A Mousa
- Klinik für Anaesthesiologie und Operative Intensivmedizin, Charité-Universitätsmedizin Berlin, Campus Benjamin Franklin, Hindenburgdamm 30, D-12200 Berlin, Germany.
| | | | | | | |
Collapse
|
23
|
Gouardères C, Zajac JM. Biochemical anti-opioid action of NPFF2 receptors in rat spinal cord. Neurosci Res 2007; 58:91-4. [PMID: 17337079 DOI: 10.1016/j.neures.2007.01.013] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2006] [Revised: 12/14/2006] [Accepted: 01/24/2007] [Indexed: 11/29/2022]
Abstract
Neuropeptide FF (NPFF) agonists counteract the cellular opioid actions. We demonstrate for the first time a biochemical anti-opioid effect of NPFF receptors in the rat spinal cord by using the [(35)S]GTPgammaS binding assay in autoradiography. The mu agonist DAMGO as well as the potent and selective NPFF(2) agonist dNPA, stimulated [(35)S]GTPgammaS binding at different optimal GDP concentrations. dNPA decreased the effects induced by DAMGO alone; the maximal of G-protein coupling was decreased but not the potency of opioid agonist. We conclude that NPFF(2) receptors are coupled to G-protein in the rat spinal cord and could exert a molecular anti-opioid effect.
Collapse
MESH Headings
- Analgesics, Opioid/metabolism
- Analgesics, Opioid/pharmacology
- Animals
- Binding, Competitive/drug effects
- Binding, Competitive/physiology
- Dose-Response Relationship, Drug
- Enkephalin, Ala(2)-MePhe(4)-Gly(5)-/pharmacology
- Guanosine 5'-O-(3-Thiotriphosphate)/metabolism
- Neurons/drug effects
- Neurons/metabolism
- Radioligand Assay
- Rats
- Rats, Sprague-Dawley
- Receptors, G-Protein-Coupled/drug effects
- Receptors, G-Protein-Coupled/metabolism
- Receptors, Neuropeptide/agonists
- Receptors, Neuropeptide/drug effects
- Receptors, Neuropeptide/metabolism
- Spinal Cord/drug effects
- Spinal Cord/metabolism
Collapse
Affiliation(s)
- Christine Gouardères
- Institut de Pharmacologie et de Biologie Structurale, CNRS UMR 5089, 205 Route de Narbonne, 31077 Toulouse Cedex, France
| | | |
Collapse
|
24
|
Abstract
Endomorphin (EM)-1 and EM-2 are tetrapeptides located within the mammalian central nervous system and immune tissues, with high affinity and specificity for micro-opioid receptors. Most of the literature has focused on the analgesic properties of EM-1 and EM-2 in animal models of neuropathic or neurogenic pain, but there is persuasive evidence emerging that EMs can also exert potent anti-inflammatory effects in both acute and chronic peripheral inflammation. The purpose of this review is to present and evaluate the evidence for anti-inflammatory properties of EM-1 and EM-2 with a view to their potential for use in chronic human inflammatory disease. Distribution of EMs within the immune system and functional roles as immunomodulatory agents are summarized and discussed. Possible milestones to be met revolve around issues of peptide stability, biodegradability problems and optimal route and method of delivery. The potential for delivery of a low-cost drug with both peripheral anti-inflammatory and analgesic properties, effective in low doses, and targeted to the site of inflammation, should focus our attention on further development of EMs as potent therapeutic agents in chronic inflammation.
Collapse
Affiliation(s)
- David S Jessop
- Henry Wellcome Laboratories for Integrative Neuroscience and Endocrinology, LINE, University of Bristol, Bristol, UK.
| |
Collapse
|
25
|
Li Z, Proud D, Zhang C, Wiehler S, McDougall JJ. Chronic arthritis down-regulates peripheral mu-opioid receptor expression with concomitant loss of endomorphin 1 antinociception. ACTA ACUST UNITED AC 2005; 52:3210-9. [PMID: 16200625 DOI: 10.1002/art.21359] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
OBJECTIVE To determine whether peripheral administration of the endogenous mu-opioid peptide endomorphin 1 could reduce knee joint pain, using animal models of acute and chronic arthritis. METHODS Extracellular electrophysiologic recordings were made of rat knee joint primary afferent nerve activity in response to noxious hyperrotation of the joint. Neuronal activity was assessed before and following local injection of endomorphin 1. Comparisons were made between normal knees and knees with adjuvant-induced monarthritis, tested at 48 hours and 1 week posttreatment. Expression of mu-opioid receptors in the dorsal root ganglia ipsilateral to the chronically inflamed joints was determined by real-time polymerase chain reaction (PCR) and immunohistochemical analysis. RESULTS In normal knees, endomorphin 1 caused up to a 75% reduction in joint afferent nerve activity, which was blocked by the mu-opioid receptor antagonist D-Phe-Cys-Tyr-D-Trp-Orn-Thr-Pen-Thr-amide. The inhibitory effect of endomorphin 1 was sustained in acutely inflamed knees. Conversely, in chronically inflamed joints, endomorphin 1 had no observable effect on the primary afferent nerve firing rate elicited by a noxious mechanical stimulus and, as such, was significantly different from the rate in normal joints. Immunohistochemical and real-time PCR analysis of the L3-L5 dorsal root ganglia ipsilateral to the chronic arthritis lesion revealed a reduction in mu-opioid receptor protein and gene expression compared with that in normal control animals. CONCLUSION Taken together, these results provide the first electrophysiologic evidence that selective activation of peripheral mu-opioid receptors reduces normal knee joint mechanosensitivity to a noxious stimulus. Furthermore, the analgesic effect of endomorphin 1 is lost during chronic inflammation due to down-regulation of mu-opioid receptor expression in afferent nerve cell bodies. These findings begin to explain the ambiguous efficacy of peripherally administered mu-opioid drugs in controlling chronic inflammatory joint pain.
Collapse
MESH Headings
- Analgesics, Opioid/pharmacology
- Animals
- Arthritis, Experimental/metabolism
- Chronic Disease
- Down-Regulation
- Edema/metabolism
- Ganglia, Spinal/cytology
- Joints/innervation
- Joints/metabolism
- Neurons, Afferent/drug effects
- Neurons, Afferent/physiology
- Nociceptors/drug effects
- Oligopeptides/pharmacology
- Pain/drug therapy
- Pain/metabolism
- RNA, Messenger/analysis
- Rats
- Rats, Wistar
- Receptors, Opioid, mu/genetics
- Receptors, Opioid, mu/metabolism
Collapse
Affiliation(s)
- Zongming Li
- University of Calgary, Calgary, Alberta, Canada
| | | | | | | | | |
Collapse
|
26
|
Abstract
The endogenous opioid system is one of the most studied innate pain-relieving systems. This system consists of widely scattered neurons that produce three opioids: beta-endorphin, the met- and leu-enkephalins, and the dynorphins. These opioids act as neurotransmitters and neuromodulators at three major classes of receptors, termed mu, delta, and kappa, and produce analgesia. Like their endogenous counterparts, the opioid drugs, or opiates, act at these same receptors to produce both analgesia and undesirable side effects. This article examines some of the recent findings about the opioid system, including interactions with other neurotransmitters, the location and existence of receptor subtypes, and how this information drives the search for better analgesics. We also consider how an understanding of the opioid system affects clinical responses to opiate administration and what the future may hold for improved pain relief. The goal of this article is to assist clinicians to develop pharmacological interventions that better meet their patient's analgesic needs.
Collapse
Affiliation(s)
- Janean E Holden
- Department of Medical-Surgical Nursing, The University of Illinois at Chicago, Illinois 60612-7350, USA.
| | | | | |
Collapse
|
27
|
Helyes Z. Role of peripheral μ-opioid receptors in arthritis: Are they potential targets for therapy? ACTA ACUST UNITED AC 2005; 52:2955-9. [PMID: 16200574 DOI: 10.1002/art.21360] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
|
28
|
Christoph T, Kögel B, Schiene K, Méen M, De Vry J, Friderichs E. Broad analgesic profile of buprenorphine in rodent models of acute and chronic pain. Eur J Pharmacol 2004; 507:87-98. [PMID: 15659298 DOI: 10.1016/j.ejphar.2004.11.052] [Citation(s) in RCA: 92] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2004] [Revised: 11/19/2004] [Accepted: 11/23/2004] [Indexed: 10/26/2022]
Abstract
Buprenorphine is a potent opioid analgesic clinically used to treat moderate to severe pain. The present study assessed its analgesic efficacy in a broad range of rodent models of acute and chronic pain. In the phenylquinone writhing, hot plate, and tail flick mouse models of acute pain, full analgesic efficacy was obtained (ED50 values: 0.0084-0.16 mg/kg i.v.). Full analgesic efficacy was also obtained in yeast- and formalin-induced inflammatory pain (ED50 values: 0.0024-0.025 mg/kg i.v., rats and mice) and in mustard-oil-induced spontaneous pain, referred allodynia, and referred hyperalgesia in mice (ED50 values: 0.018-0.025 mg/kg i.v.). Buprenorphine strongly inhibited mechanical and cold allodynia in mononeuropathic rats, as well as mechanical hyperalgesia and cold allodynia in polyneuropathic rats (ED50 values: 0.055 and 0.036 mg/kg i.v. and 0.129 and 0.038 mg/kg i.p., respectively). It is concluded that buprenorphine shows a broad analgesic profile and offers the opportunity to treat different pain conditions, including neuropathic pain.
Collapse
Affiliation(s)
- Thomas Christoph
- Department of Pharmacology, Grünenthal GmbH Research and Development, Zieglerstrasse 6, D-52078 Aachen, Germany.
| | | | | | | | | | | |
Collapse
|
29
|
Abstract
This paper is the 26th consecutive installment of the annual review of research concerning the endogenous opioid system, now spanning over a quarter-century of research. It summarizes papers published during 2003 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 (Section 2), and the roles of these opioid peptides and receptors in pain and analgesia (Section 3); stress and social status (Section 4); tolerance and dependence (Section 5); learning and memory (Section 6); eating and drinking (Section 7); alcohol and drugs of abuse (Section 8); sexual activity and hormones, pregnancy, development and endocrinology (Section 9); mental illness and mood (Section 10); seizures and neurologic disorders (Section 11); electrical-related activity and neurophysiology (Section 12); general activity and locomotion (Section 13); gastrointestinal, renal and hepatic functions (Section 14); cardiovascular responses (Section 15); respiration and thermoregulation (Section 16); and immunological responses (Section 17).
Collapse
Affiliation(s)
- Richard J Bodnar
- Department of Psychology and Neuropsychology, Doctoral Sub-Program, Queens College, City University of New York, 65-30 Kissena Blvd., Flushing, NY 11367, USA.
| | | |
Collapse
|