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Thompson SJ, Pitcher MH, Stone LS, Tarum F, Niu G, Chen X, Kiesewetter DO, Schweinhardt P, Bushnell MC. Chronic neuropathic pain reduces opioid receptor availability with associated anhedonia in rat. Pain 2019; 159:1856-1866. [PMID: 29794614 PMCID: PMC6095806 DOI: 10.1097/j.pain.0000000000001282] [Citation(s) in RCA: 60] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Supplemental Digital Content is Available in the Text. Chronic pain reduces opioid receptor expression in the rat striatum, where the correlation between receptor expression and anhedonia may represent a molecular substrate for comorbid depression. The opioid system plays a critical role in both the experience and management of pain. Although acute activation of the opioid system can lead to pain relief, the effects of chronic pain on the opioid system remain opaque. Cross-sectional positron emission tomography (PET) studies show reduced availability of brain opioid receptors in patients with chronic pain but are unable to (1) determine whether these changes are due to the chronic pain itself or due to preexisting or medication-induced differences in the endogenous opioid system, and (2) identify the neurobiological substrate of reduced opioid receptor availability. We investigated these possibilities using a well-controlled longitudinal study design in rat. Using [18F]-FDPN-PET in either sham rats (n = 17) or spared nerve injury rats (n = 17), we confirmed reduced opioid receptor availability in the insula, caudate–putamen, and motor cortex of nerve injured rats 3 months after surgery, indicating that painful neuropathy altered the endogenous opioid system. Immunohistochemistry showed reduced expression of the mu-opioid receptor, MOR1, in the caudate–putamen and insula. Neither the opioid peptide enkephalin nor the neuronal marker NeuN differed between groups. In nerve-injured animals, sucrose preference, a measure of anhedonia/depression-like behavior, positively correlated with PET opioid receptor availability and MOR1-immunoreactivity in the caudate–putamen. These findings provide new evidence that the altered supraspinal opioid receptor availability observed in human patients with chronic pain may be a direct result of chronic pain. Moreover, reduced opioid receptor availability seems to reflect decreased receptor expression, which may contribute to pain-induced depression.
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Affiliation(s)
- Scott J Thompson
- Division of Intramural Research, National Center for Complementary and Integrative Health, National Institutes of Health, Bethesda, MD, United States.,Faculty of Dentistry, McGill University, Montreal, QC, Canada
| | - Mark H Pitcher
- Division of Intramural Research, National Center for Complementary and Integrative Health, National Institutes of Health, Bethesda, MD, United States
| | - Laura S Stone
- Faculty of Dentistry, McGill University, Montreal, QC, Canada
| | - Farid Tarum
- Division of Intramural Research, National Center for Complementary and Integrative Health, National Institutes of Health, Bethesda, MD, United States
| | - Gang Niu
- Division of Intramural Research, National Institute of Biomedical Imaging and Bioengineering, National Institutes of Health, Bethesda, MD, United States
| | - Xiaoyuan Chen
- Division of Intramural Research, National Institute of Biomedical Imaging and Bioengineering, National Institutes of Health, Bethesda, MD, United States
| | - Dale O Kiesewetter
- Division of Intramural Research, National Institute of Biomedical Imaging and Bioengineering, National Institutes of Health, Bethesda, MD, United States
| | | | - M Catherine Bushnell
- Division of Intramural Research, National Center for Complementary and Integrative Health, National Institutes of Health, Bethesda, MD, United States
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2
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Taylor BK, Corder G. Endogenous analgesia, dependence, and latent pain sensitization. Curr Top Behav Neurosci 2014; 20:283-325. [PMID: 25227929 PMCID: PMC4464817 DOI: 10.1007/7854_2014_351] [Citation(s) in RCA: 54] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Endogenous activation of µ-opioid receptors (MORs) provides relief from acute pain. Recent studies have established that tissue inflammation produces latent pain sensitization (LS) that is masked by spinal MOR signaling for months, even after complete recovery from injury and re-establishment of normal pain thresholds. Disruption with MOR inverse agonists reinstates pain and precipitates cellular, somatic, and aversive signs of physical withdrawal; this phenomenon requires N-methyl-D-aspartate receptor-mediated activation of calcium-sensitive adenylyl cyclase type 1 (AC1). In this review, we present a new conceptual model of the transition from acute to chronic pain, based on the delicate balance between LS and endogenous analgesia that develops after painful tissue injury. First, injury activates pain pathways. Second, the spinal cord establishes MOR constitutive activity (MORCA) as it attempts to control pain. Third, over time, the body becomes dependent on MORCA, which paradoxically sensitizes pain pathways. Stress or injury escalates opposing inhibitory and excitatory influences on nociceptive processing as a pathological consequence of increased endogenous opioid tone. Pain begets MORCA begets pain vulnerability in a vicious cycle. The final result is a silent insidious state characterized by the escalation of two opposing excitatory and inhibitory influences on pain transmission: LS mediated by AC1 (which maintains the accelerator) and pain inhibition mediated by MORCA (which maintains the brake). This raises the prospect that opposing homeostatic interactions between MORCA analgesia and latent NMDAR-AC1-mediated pain sensitization creates a lasting vulnerability to develop chronic pain. Thus, chronic pain syndromes may result from a failure in constitutive signaling of spinal MORs and a loss of endogenous analgesic control. An overarching long-term therapeutic goal of future research is to alleviate chronic pain by either (a) facilitating endogenous opioid analgesia, thus restricting LS within a state of remission, or (b) extinguishing LS altogether.
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Affiliation(s)
- Bradley K Taylor
- Department of Physiology, School of Medicine, University of Kentucky Medical Center, Lexington, KY, 40536-0298, USA,
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La Porta C, Bura SA, Aracil-Fernández A, Manzanares J, Maldonado R. Role of CB1 and CB2 cannabinoid receptors in the development of joint pain induced by monosodium iodoacetate. Pain 2013. [DOI: 10.1016/j.pain.2012.10.009] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
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4
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Shen PC, Shiau AL, Jou IM, Lee CH, Tai MH, Juan HY, Lin PR, Liu GS, Wu CL, Hsieh JL. Inhibition of cartilage damage by pro-opiomelanocortin prohormone overexpression in a rat model of osteoarthritis. Exp Biol Med (Maywood) 2011; 236:334-40. [DOI: 10.1258/ebm.2010.010319] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Pro-opiomelanocortin (POMC) is a precursor of various neuropeptides. POMC-derived neuropeptides are potent inflammation inhibitors and immunosuppressants. Evidence that osteoarthritis (OA) is an inflammatory disease is accumulating. We assessed whether intra-articular gene delivery of POMC ameliorates experimentally induced OA in a rat model. OA was induced in Wistar rats by anterior cruciate ligament-transection (ACLT) in the knee of one hind limb. Adenoviral vector encoding human POMC (AdPOMC) was injected intra-articularly into the knee joints after ACLT. The transgene expression and the inflammatory responses were evaluated using immunoblotting, immunohistochemistry and enzyme-linked immunosorbent assay. The treated joints were assessed histologically for manifestations of the disease. Human POMC was expressed in the chondrocytes and synovial membrane after the intra-articular injection. POMC gene transfer reduced nuclear factor- κB activity and the levels of interleukin-1 β in HTB-94 chondrosarcoma cells and Raw 264.7 macrophages; it also reduced microvessel density in the synovium. Histological examination showed that symptoms of OA in AdPOMC-treated rats were less severe than in rats treated with either empty adenoviral vector (AdNull) or normal saline. Intra-articular injection of adenoviral vectors expressing POMC significantly suppressed the progression and severity of OA, and reduced inflammatory responses and angiogenesis. POMC gene delivery may offer novel therapeutic approach for treating OA.
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Affiliation(s)
- Po-Chuan Shen
- Department of Orthopedic Surgery, Tainan Hospital, Department of Health, Executive Yuan, Tainan 70043
| | | | - I-Ming Jou
- Department of Orthopedics, National Cheng Kung University Medical College, Tainan 70101
| | - Che-Hsin Lee
- Department of Microbiology, School of Medicine, China Medical University, Taichung 40402
| | - Ming-Hong Tai
- Institute of Biomedical Sciences, National Sun Yat-Sen University, Kaohsiung 804
| | | | - Pey-Ru Lin
- Department of Microbiology and Immunology
| | - Guei-Sheung Liu
- Graduate Institute of Medicine, Kaohsiung Medical University, Kaohsiung 807
| | - Chao-Liang Wu
- Department of Biochemistry and Molecular Biology, National Cheng Kung University Medical College, 1 University Road, Tainan 70101
| | - Jeng-Long Hsieh
- Department of Nursing, Chung Hwa University of Medical Technology, 89 Wun-Hwa 1st Street, Jen-Te, Tainan Hsien 717, Taiwan
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N-Methyl-D-Aspartate Receptor-Mediated Chronic Pain: New Approaches to Fibromyalgia Syndrome Etiology and Therapy. ACTA ACUST UNITED AC 2010. [DOI: 10.1300/j094v15n02_07] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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6
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Pinto M, Castro AR, Tshudy F, Wilson SP, Lima D, Tavares I. Opioids modulate pain facilitation from the dorsal reticular nucleus. Mol Cell Neurosci 2008; 39:508-18. [DOI: 10.1016/j.mcn.2008.07.008] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2008] [Revised: 07/03/2008] [Accepted: 07/08/2008] [Indexed: 11/25/2022] Open
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Schepers R, Mahoney JL, Gehrke BJ, Shippenberg TS. Endogenous kappa-opioid receptor systems inhibit hyperalgesia associated with localized peripheral inflammation. Pain 2008; 138:423-439. [PMID: 18355964 PMCID: PMC2553515 DOI: 10.1016/j.pain.2008.01.023] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2007] [Revised: 12/20/2007] [Accepted: 01/22/2008] [Indexed: 11/20/2022]
Abstract
Peripheral inflammation evokes functional and biochemical changes in the periphery and spinal cord which result in central sensitization and hypersensitivity. Inhibitory control systems from the rostral ventromedial medulla (RVM) are also activated. The present study investigates whether endogenous kappa-opioid receptor (KOPr) systems contribute to these neuroadaptations. Inflammation was induced by intraplantar injection of complete Freund's adjuvant (CFA) into one hindpaw. Mechanical and thermal thresholds were determined using the Von Frey and radiant heat tests, respectively. KOPr gene deletion in mice or systemic administration of the long-acting KOPr antagonist, norbinaltorphimine (norBNI) significantly exacerbated mechanical and thermal hypersensitivity of the ipsilateral, inflamed paw. Thermal and mechanical thresholds of the non-inflamed, contralateral hindpaw were unaffected by CFA treatment. However, gene deletion as well as norBNI treatment resulted in mechanical, but not thermal hypersensitivity of the non-inflamed paw. Similar results were obtained when norBNI was administered intrathecally or into the RVM in rats. These data demonstrate a previously unrecognized role of endogenous KOPr systems in inhibiting hyperalgesia during inflammation. Furthermore, they demonstrate that decreased KOPr activity in either the spinal cord or RVM not only enhances mechanical and thermal hyperalgesia of the inflamed limb but also leads to an unmasking of mechanical hyperalgesia at a site remote from inflammation. The differential effects of KOPr antagonism on mechanical versus thermal thresholds for the non-inflamed paw support the notion that distinct neuroanatomical or neurochemical mechanisms modulate the processing of thermal versus mechanical stimuli.
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Affiliation(s)
- R.J. Schepers
- University of Maryland School of Medicine, 660 West Redwood Street, Baltimore, MD 21201, USA
- Integrative Neuroscience Section, Behavioral Neuroscience Branch, National Institutes of Health/National Institute on Drug Abuse Intramural Research Program, 333 Cassell Drive, Baltimore, MD 21224, USA
| | - Janet Lynn Mahoney
- Integrative Neuroscience Section, Behavioral Neuroscience Branch, National Institutes of Health/National Institute on Drug Abuse Intramural Research Program, 333 Cassell Drive, Baltimore, MD 21224, USA
| | - Brenda Jean Gehrke
- Integrative Neuroscience Section, Behavioral Neuroscience Branch, National Institutes of Health/National Institute on Drug Abuse Intramural Research Program, 333 Cassell Drive, Baltimore, MD 21224, USA
| | - Toni Shaun Shippenberg
- Integrative Neuroscience Section, Behavioral Neuroscience Branch, National Institutes of Health/National Institute on Drug Abuse Intramural Research Program, 333 Cassell Drive, Baltimore, MD 21224, USA
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8
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Neto FL, Carvalhosa AR, Ferreira-Gomes J, Reguenga C, Castro-Lopes JM. Delta opioid receptor mRNA expression is changed in the thalamus and brainstem of monoarthritic rats. J Chem Neuroanat 2008; 36:122-7. [PMID: 18572383 DOI: 10.1016/j.jchemneu.2008.05.004] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2008] [Revised: 05/09/2008] [Accepted: 05/09/2008] [Indexed: 11/27/2022]
Abstract
Changes in the mRNA expression of neurotransmitters receptors under chronic pain conditions have been described in various areas of the central nervous system (CNS). Delta opioid receptors (DORs) have been implicated in pain mechanisms but, although its mRNA expression has been studied in the rat CNS, there are no reports describing its distribution in specific thalamic and brainstem nuclei during chronic inflammatory pain. Here, in situ hybridization for DOR mRNA was performed in brain sections from control and monoarthritic (MA) rats with 2, 4, 7 and 14 days of inflammation. Grain densities were determined bilaterally in the ventrobasal complex (VB), posterior (Po), centromedial/centrolateral (CM/CL) and reticular (Rt) nuclei of the thalamus, and in the dorsal reticular (DRt), lateral reticular (LRt) and parvocellular reticular (PCRt) nuclei of the brainstem. Control animals exhibited weak mRNA expression in the VB, Po and CM/CL, as well as in PCRt, while moderate grain densities were observed in the Rt, DRt and LRt. During MA, DOR mRNA expression was significantly decreased (22%) in the Rt contralateral to the affected joint at both 7 and 14 days of inflammation, as compared to controls. A bilateral reduction (35%) was also observed in the DRt at 14 days of MA, while a contralateral increase was found in the PCRt at 7 days (+39%). No significant changes were observed in the other regions analyzed. Thus, data show changes in the DOR mRNA expression during the development of chronic inflammatory pain, in thalamic and brainstem nuclei implicated in pain processing mechanisms.
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Affiliation(s)
- Fani Lourença Neto
- Institute of Histology and Embryology, Faculty of Medicine of Porto and IBMC, University of Porto, Portugal.
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9
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Sato E, Takano Y, Kuno Y, Takano M, Sato I. Involvement of spinal tyrosine kinase in inflammatory and N-methyl-D-aspartate-induced hyperalgesia in rats. Eur J Pharmacol 2003; 468:191-8. [PMID: 12754057 DOI: 10.1016/s0014-2999(03)01718-7] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Phosphorylation of a subunit of N-methyl-D-aspartate (NMDA) receptor by protein tyrosine kinase (PTK) Src or Trk is known to enhance its channel activity. We examined whether a spinally administered selective PTK inhibitor, lavendustin A, which has high affinity for Src and Trk tyrosine kinases, could influence the development and maintenance of inflammatory hyperalgesia or NMDA-induced hyperalgesia. Inflammation was induced by injection of a mixture of carrageenan and kaolin into the tail base of rats. In another group of rats, hyperalgesia was induced by intrathecal administration of NMDA. Intrathecal administration of lavendustin A (1.0 microg) or NMDA receptor antagonist, (+)-5-methyl-10,11-dihydro-5H-dibenzo[a,d]cycloheptane-5,10-iminemaleate, MK-801 (3.0 microg) before injection of a mixture of carrageenan and kaolin or after the development of inflammation inhibited carrageenan-kaolin-induced mechanical hyperalgesia. Intrathecal injection of 1.0 microg NMDA produced thermal and mechanical hyperalgesia. Co-administration of 1.0 microg lavendustin A with NMDA significantly reduced the duration of spontaneous pain behaviour and inhibited NMDA-induced hyperalgesia. Lavendustin A itself did not cause any sedation, motor impairment or analgesia. Our results suggest that inhibition of PTK could be therapeutically effective as an analgesic in some NMDA receptor-mediated hyperalgesic states.
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Affiliation(s)
- Eiru Sato
- Department of Anesthesiology, Koshigaya Hospital, Dokkyo University, School of Medicine, 2-1-50 Minami-Koshigaya, Saitama 343-8555, Koshigaya City, Japan.
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Parra MC, Nguyen TN, Hurley RW, Hammond DL. Persistent inflammatory nociception increases levels of dynorphin1-17 in the spinal cord, but not in supraspinal nuclei involved in pain modulation. THE JOURNAL OF PAIN 2002; 3:330-6. [PMID: 14622757 DOI: 10.1054/jpai.2002.125185] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
It is well established that nerve injury or inflammatory injury results in a time-dependent increase in the expression of dynorphin in the spinal cord. However, little is known about the effects of persistent pain on the expression of this endogenous opioid peptide by supraspinal nuclei implicated in the modulation of pain sensitivity. This study used enzyme-linked immunosorbent assay to measure the levels of dynorphin(1-17) in the spinal cord as well as in brainstem nuclei 4 hours, 4 days, or 2 weeks after intraplantar injection of saline or complete Freund's adjuvant in the left hind paw. As previously reported, complete Freund adjuvant produced a time-dependent increase in dynorphin that was confined to the ipsilateral dorsal horn. In contrast, levels of dynorphin(1-17) in the nucleus raphe magnus, nucleus reticularis gigantocellularis pars alpha, parabrachial nuclei, microcellular tegmentum, pontine periaqueductal gray, and midbrain periaqueductal gray were not affected at any time after injection of complete Freund adjuvant. These data suggest that alterations in levels of dynorphin do not mediate the up-regulation of activity in bulbospinal pain inhibitory or pain facilitatory pathways that occurs during persistent pain.
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11
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Affiliation(s)
- S L Ingram
- Vollum Institute, Oregon Health Sciences University, Portland 97201, USA.
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12
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The analgesic effects of supraspinal mu and delta opioid receptor agonists are potentiated during persistent inflammation. J Neurosci 2000. [PMID: 10648729 DOI: 10.1523/jneurosci.20-03-01249.2000] [Citation(s) in RCA: 157] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
This study examined the antihyperalgesic and antinociceptive effects of opioid receptor agonists microinjected in the rostral ventromedial medulla (RVM) of rats 4 hr, 4 d, and 2 weeks after the induction of an inflammatory injury by injection of complete Freund's adjuvant (CFA) in one hindpaw. Nociceptive sensitivity of the ipsilateral, inflamed and the contralateral, uninflamed hindpaws was determined by the radiant-heat paw withdrawal test. The antihyperalgesic potency of the mu opioid receptor agonist [D-Ala(2),N-Me-Phe(4),Gly(5)-ol]enkephalin (DAMGO), determined for the inflamed hindpaw, was enhanced 4 d and 2 weeks after injury. The antinociceptive potency of DAMGO, determined for the contralateral, uninflamed hindpaw, was also progressively enhanced 4 hr, 4 d, and 2 weeks after injury. The magnitude of enhancement paralleled the chronicity of the injury. The greatest potentiation occurred 2 weeks after injury when the ED(50) value of DAMGO in CFA-treated rats was one-tenth that in saline-treated rats. The antihyperalgesic and antinociceptive effects of the delta opioid receptor agonist [D-Ala(2),Glu(4)]deltorphin were also increased 2 weeks after injury. These results indicate that peripheral inflammatory injury alters the pharmacology of excitatory and inhibitory inputs that modulate the activity of RVM neurons in such a manner as to enhance the effects of opioid agonists in this region. These changes have ramifications not only for the alleviation of hyperalgesia at the site of injury but also for opioid-induced antinociception at sites remote to the injury as revealed by increases in the potency of opioid agonists to suppress nociceptive responses of the contralateral, uninflamed hindpaw.
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Kato M, Taguchi K, Hagiwara Y, Kubo T. Effects of electrical stimulation and morphine microinjection into periaqueductal gray on 5-hydroxyindole oxidation current in spinal cord of cats. GENERAL PHARMACOLOGY 1996; 27:1195-201. [PMID: 8981067 DOI: 10.1016/s0306-3623(96)00057-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
1. The effects of electrical stimulation and microinjection of morphine into the periaqueductal gray (PAG) on the 5-hydroxyindole oxidation current (280-300 mV) in laminae I-VI (800-2500 microns) of the spinal cord were examined using in vivo voltammetry in anesthetized cats. 2. Electrical stimulation of the PAG (PAG-S) both enhanced and attenuated the current. PAG-S increased the signal by 13.3 +/- 3.7% (laminae I-II: 800-1200 microns) or 19.0 +/- 3.6% (laminae V-VI: 1700-2500 microns) in comparison to control values. Attenuation by PAG-S decreased the signal by 15.3 +/- 2.6% (laminae I-II) or 13.3 +/- 2.0% (laminae V-VI) of control values. Naloxone antagonized signal enhancement by PAG-S. 3. Morphine (10 micrograms/microliter) microinjected into the PAG significantly increased the height of the signal (laminae I-II: 15.0 +/- 3.4%, laminae V-VI: 12.2 +/- 1.5%). Enhancement by microinjected morphine was antagonized by naloxone. In contrast, microinjected morphine also significantly decreased the signal by 10.4 +/- 2.7% (laminae I-II) and by 10.3 +/- 1.3% (laminae V-VI) of control values. 4. Microinjection of morphine and electrical stimulation of the PAG was observed both to enhance and attenuate the oxidation current of 5-hydroxyindole in the superficial and deeper dorsal horn. PAG may function to regulate the RVM-spinal serotonergic pathway, which modulates the transmission of nociceptive messages at the spinal cord.
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Affiliation(s)
- M Kato
- Department of Pharmacology, Showa College of Pharmaceutical Sciences, Tokyo, Japan
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14
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Williams FG, Mullet MA, Beitz AJ. Basal release of Met-enkephalin and neurotensin in the ventrolateral periaqueductal gray matter of the rat: a microdialysis study of antinociceptive circuits. Brain Res 1995; 690:207-16. [PMID: 8535838 DOI: 10.1016/0006-8993(95)00554-4] [Citation(s) in RCA: 68] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The periaqueductal gray (PAG) contains neural circuits that participate in descending antinociception. Anatomical and electrophysiological evidence suggests that these circuits might employ opioid peptides and GABA in series to remove a tonic inhibition of descending PAG output neurons. The present studies examined the release of the antinociceptive peptides Met-enkephalin and neurotensin in the ventrolateral PAG, and investigated the interaction between GABA and Met-enkephalin release. In awake and freely moving rats the ventrolateral PAG was dialysed using 25 ga. concentric probes. Basal release of peptide in 12 min or 40 min fractions was determined using radioimmunoassays. To establish how the ventrolateral PAG responds to nociception, dialysis was performed following unilateral hindpaw inflammation using Complete Freund's Adjuvant. Twenty-four hours after inflammation was induced, neurotensin release was increased 133% and Met-enkephalin release was increased 353% compared to control animals. Seven days after inflammation was induced, neurotensin release declined precipitously, while basal Met-enkephalin release remained elevated 313% above controls. Thus, unlike enkephalin, increased basal neurotensin release is not sustained with persistent tonic nociception. In addition, we confirmed in normal animals that the ventrolateral PAG is induced to release Met-enkephalin by systemic morphine. A 43% increase in basal Met-enkephalin release was observed immediately following a 12 mg/kg i.p. morphine injection. Morphine should have the opposite effect (inhibit peptide release) if it acts directly on the enkephalinergic neurons. Thus, we examined the hypothesis that GABAergic interneurons in the PAG mediated morphine-stimulated enkephalin release. When the GABAantagonist bicuculline (0.25 microM to 25 microM) was co-infused with the dialysis medium, Met-enkephalin release increased in a dose-dependent fashion and peaked 68% above pre-infusion levels. These data elucidate the reciprocal inhibitory relationship between GABA and enkephalin in the ventrolateral PAG. We hypothesize that, when nociception induces Met-enkephalin release within this region, the tonic GABAergic inhibition is overcome, resulting in greater sensitivity of PAG enkephalinergic neurons. Ultimately, this enhanced enkephalin release should result in greater excitability of the descending PAG output neurons that are responsible for antinociception.
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Affiliation(s)
- F G Williams
- Department of Veterinary Biology, College of Veterinary Medicine, University of Minnesota, St. Paul 55108, USA
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15
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Minami M, Satoh M. Molecular biology of the opioid receptors: structures, functions and distributions. Neurosci Res 1995; 23:121-45. [PMID: 8532211 DOI: 10.1016/0168-0102(95)00933-k] [Citation(s) in RCA: 216] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Opiates like morphine and endogenous opioid peptides exert their pharmacological and physiological effects through binding to their endogenous receptors, opioid receptors. The opioid receptors are classified into at least three types, mu-, delta- and kappa-types. Recently, cDNAs of the opioid receptors have been cloned and have greatly advanced our understanding of their structure, function and expression. This review focuses on the recent advances in the studies on opioid receptors using the cloned cDNAs. We describe the molecular cloning of the opioid receptor gene family and studies of the structure-function relationships, modes of coupling to second messenger systems, pharmacological effects of antisense oligonucleotide and anatomical distributions of opioid receptors.
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Affiliation(s)
- M Minami
- Department of Molecular Pharmacology, Faculty of Pharmaceutical Sciences, Kyoto University, Japan
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16
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Abstract
Opioid receptors are the primary sites of actions of opiates and endogenous opioid peptides, which have a wide variety of pharmacological and physiological effects. The opioid receptors are classified into at least three subtypes, mu, delta, and kappa, and their cDNAs have been cloned. In this review, we describe the molecular cloning of opioid receptor gene family and studies of the structure-function relationships, modes of coupling to second messenger systems, pharmacological effects of antisense oligonucleotides, and anatomical distribution of opioid receptor mRNAs.
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MESH Headings
- Amino Acid Sequence
- Central Nervous System/metabolism
- Ganglia, Spinal/metabolism
- Molecular Sequence Data
- RNA, Messenger/analysis
- Receptors, Opioid/genetics
- Receptors, Opioid/metabolism
- Receptors, Opioid, delta/genetics
- Receptors, Opioid, delta/metabolism
- Receptors, Opioid, kappa/genetics
- Receptors, Opioid, kappa/metabolism
- Receptors, Opioid, mu/genetics
- Receptors, Opioid, mu/metabolism
- Second Messenger Systems/physiology
- Sequence Homology, Amino Acid
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Affiliation(s)
- M Satoh
- Department of Molecular Pharmacology, Kyoto University, Japan
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Luthra S, Brady F, Turton D, Brown D, Dowsett K, Waters S, Jones A, Matthews R, Crowder J. Automated radiosyntheses of [6-O-methyl-11C]diprenorphine and [6-O-methyl-11C]buprenorphine from 3-O-trityl protected precursors. Appl Radiat Isot 1994. [DOI: 10.1016/0969-8043(94)90217-8] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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Maldonado R, Valverde O, Turcaud S, Fournié-Zaluski MC, Roques BP. Antinociceptive response induced by mixed inhibitors of enkephalin catabolism in peripheral inflammation. Pain 1994; 58:77-83. [PMID: 7970841 DOI: 10.1016/0304-3959(94)90186-4] [Citation(s) in RCA: 48] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
RB101 (N-((R,S)-2-benzyl-3[(S)(2-amino-4-methylthio)butyl dithio]-1-ox-opropyl)-L-phenylalanine benzyl ester) is a recently developed full inhibitor of the enkephalin-catabolizing enzymes able to cross the blood-brain barrier, whereas RB38A ((R)-3-(N-hydroxycarboxamido-2-benzylpropanoyl)-L-phenylalanine) is as potent as RB101 but almost unable to enter the brain. In this study, we have investigated the effects of systemic administration of morphine, RB101 and RB38A on nociception induced by pressure on inflamed peripheral tissues. Antinociceptive test was performed between 4 and 5 days after injection into the rat left hindpaw of Freund's complete adjuvant to produce localized inflammation. Morphine (1, 2 and 4 mg/kg, i.v.) induced antinociception in inflamed paws at all the doses used, and only at the highest dose in non-inflamed paws. RB101 (10 and 20 mg/kg, i.v.) induced an antinociceptive response only in the inflamed paws. RB38A, also induced an antinociceptive effect in the inflamed paws, but only at the highest dose (20 mg/kg, i.v.). The responses induced by morphine and the inhibitors of enkephalin catabolism were antagonized by the systemic administration of naloxone (1 mg/kg) or methylnaloxonium (2 mg/kg) which acts essentially outside the brain. Central injection (i.c.v.) of methylnaloxonium (2 micrograms) blocked the effect of morphine only in non-inflamed paws, and slightly decreased the response induced by RB101 on inflamed paws. These results indicate that the endogenous opioid peptides, probably enkephalins, are important in the peripheral control of nociception from inflamed tissues.
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Affiliation(s)
- R Maldonado
- Department of Molecular and Structural Pharmacochemistry, U266 INSERM/URA D1500 CNRS, University René Descartes, UFR of Pharmaceutical and Biological Sciences, Faculty of Pharmacy, 75270 Paris Cedex 06 France
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19
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Minami M, Hosoi Y, Toya T, Katao Y, Maekawa K, Katsumata S, Yabuuchi K, Onogi T, Satoh M. In situ hybridization study of kappa-opioid receptor mRNA in the rat brain. Neurosci Lett 1993; 162:161-4. [PMID: 7907172 DOI: 10.1016/0304-3940(93)90585-9] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Distribution of kappa-opioid receptor mRNA in rat brain was examined by in situ hybridization technique. kappa-Opioid receptor mRNA was expressed in various brain regions, especially intensely in the neocortex (layer V and VI), caudate-putamen, nucleus accumbens, preoptic area, paraventricular thalamic nucleus, amygdala, several nuclei of hypothalamus, ventral tegmental area and substantia nigra pars compacta.
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Affiliation(s)
- M Minami
- Department of Pharmacology, Faculty of Pharmaceutical Sciences, Kyoto University, Japan
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20
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Herrero JF, Headley PM. The effects of sham and full spinalization on the systemic potency of mu- and kappa-opioids on spinal nociceptive reflexes in rats. Br J Pharmacol 1991; 104:166-70. [PMID: 1664760 PMCID: PMC1908269 DOI: 10.1111/j.1476-5381.1991.tb12402.x] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
1. Flexor withdrawal reflexes to noxious mechanical pinch stimuli were recorded as single motor unit activity in alpha-chloralose anaesthetized rats, by means of tungsten bipolar electrodes inserted percutaneously into hindlimb flexor muscles. The relative spinal and supraspinal contributions to mu- and kappa-opioid agonists in inhibiting these spinal reflexes, together with possible potency changes elicited by surgical trauma, were examined by comparing their relative potencies in spinally unoperated, sham spinalized and spinalized rats. 2. The noxious stimuli, which were of comparable intensity in the three groups, elicited similar mean firing rates of the motor units in all groups. This indicates that the excitability levels in the reflex pathway were not greatly affected by either sham or actual spinalization. 3. The mu-agonists morphine and fentanyl, and the kappa-agonist U-50,488H, inhibited the reflexes in a dose-dependent manner, when administered intravenously in a log2 cumulative dose regime. 4. The surgery of sham spinalization had little effect on the potency of morphine and fentanyl, whereas it doubled the potency of U-50,488. 5. Spinalization did not affect the potency of morphine. In contrast it decreased the potency of fentanyl 2-4 fold and that of U-50,488 approximately 6 fold. 6. The effects of all agonists were antagonized by naloxone. Dose-dependence studies indicating that antagonism of U-50,488H required about 5 times the dose of naloxone that antagonized morphine. 7. The data suggest that surgical trauma to the spinal column and/or dura mater triggers supraspinal mechanisms that significantly enhance the potency of kappa- but not mu-agonists. 8. It is concluded that most of the effects of systemic morphine on spinal reflexes are mediated, under all three conditions tested, by direct effects in the spinal cord. In contrast, the inhibition of reflexes by U-50,488H is mediated at both spinal and supraspinal levels, the latter being enhanced in the presence of surgical trauma. The differences between morphine and fentanyl remain unexplained.
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Affiliation(s)
- J F Herrero
- Department of Physiology, School of Medical Sciences, University of Bristol
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21
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Takahashi O, Shiosaka S, Traub RJ, Ruda MA. Ultrastructural demonstration of synaptic connections between calcitonin gene-related peptide immunoreactive axons and dynorphin A(1-8) immunoreactive dorsal horn neurons in a rat model of peripheral inflammation and hyperalgesia. Peptides 1990; 11:1233-7. [PMID: 1982351 DOI: 10.1016/0196-9781(90)90157-z] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Synaptic contact between dynorphin A(1-8)-like immunoreactive lamina V spinal neurons and calcitonin gene-related peptide-like immunoreactive axon terminals was demonstrated using the immuno-electron microscopic mirror technique in a rat model of peripheral inflammation and hyperalgesia. Adjacent tissue sections were immunocytochemically labeled for either dynorphin A(1-8) or calcitonin gene-related peptide and examined at the electron microscopic level for the presence of synaptic contacts. The results suggest that some opioid neurons which exhibit a dynamic increase in dynorphin peptide associated with peripheral inflammation and hyperalgesia receive direct monosynaptic input from presumptive nociceptive primary afferents.
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Affiliation(s)
- O Takahashi
- Neurobiology and Anesthesiology Branch, National Institute of Dental Research, National Institutes of Health, Bethesda, MD 20892
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22
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Riesenberg R, Nitsch C. Two different types of dynorphin-A-immunoreactive terminals in rat substantia nigra. Cell Tissue Res 1990; 261:107-13. [PMID: 1974480 DOI: 10.1007/bf00329443] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
The opioid peptide dynorphin A (1-17) is the third transmitter identified in the striatonigral projection, the other two being gamma-aminobutyric acid (GABA) and substance P. The ultrastructural features of the dynorphinergic terminals in substantia nigra/pars reticulata were studied using pre-embedding immunocytochemistry with the classical peroxidase-antiperoxidase-diaminobenzidine-method; these features were compared with GABAergic boutons visualized with an immunogold method. Two distinct types of dynorphin-A-immunoreactive boutons could be identified: (1) type A (81%) possessing characteristics similar to the GABAergic nerve endings in this region, i.e., large pleomorphic vesicles and symmetric synaptic contacts; (2) type B (19%) displaying asymmetric synaptic zones and small, mostly round vesicles. These results are in agreement with physiological studies suggesting a dual action of dynorphin A in substantia nigra.
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Affiliation(s)
- R Riesenberg
- Anatomische Anstalt, Universität München, Federal Republic of Germany
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23
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Abstract
Over the past decade, opioids have attracted great attention. One important reason for this is the need for novel, strong analgesics free of the abuse potential and side-effects of narcotics such as morphine. Because morphine acts at mu-opioid receptors, efforts have been made to characterize analgesia mediated by non-mu sites, in particular kappa-opioid receptors. There is now good evidence that kappa-receptors do indeed mediate analgesia. However, kappa-agonists display properties that could curtail their therapeutic exploitation. Since the first selective kappa-agonists are now entering clinical trials, this is an opportune moment for Mark Millan to review the pharmacology of drugs of this type in the control of nociception and their therapeutic potential as analgesics.
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Affiliation(s)
- M J Millan
- Fondax, Neurobiology Division, Groupe de Recherches Servier, Paris, France
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24
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Abstract
Although an opioid-mediated mechanism appears to be involved in the alteration of pain perception during feeding behavior, little is known about macronutrient effects on nociception. In this report we show that prolonged sucrose feeding alters responsiveness to painful stimuli and the analgesic potency of morphine. Male Sprague-Dawley rats maintained on ad lib laboratory chow with continuous access to a 20% sucrose solution displayed a significant decrease in tail-flick latency as early as 20 hours after introduction of the sucrose. The differences in pain threshold were naloxone sensitive. After 25 days on the diet, morphine sulfate, 8 mg/kg administered IP, proved to be significantly more potent in the sucrose-fed animals. The results indicate that sucrose feeding alters endogenous opioid-mediated nociception.
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Affiliation(s)
- D S Roane
- Department of Foods and Nutrition, University of Georgia, Athens 30602
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25
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Kayser V, Fournie-Zaluski MC, Guilbaud G, Roques BP. Potent antinociceptive effects of kelatorphan (a highly efficient inhibitor of multiple enkephalin-degrading enzymes) systemically administered in normal and arthritic rats. Brain Res 1989; 497:94-101. [PMID: 2790459 DOI: 10.1016/0006-8993(89)90974-8] [Citation(s) in RCA: 70] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
The effects of various i.v. doses (2.5, 5, 10 and 15 mg/kg) of the highly efficient inhibitor of multiple enkephalin-degrading enzymes, Kelatorphan, were evaluated on the vocalization threshold to paw pressure in normal rats and in rats with Freund's adjuvant-induced arthritis. In normal rats, Kelatorphan at doses as low as 2.5 mg/kg i.v. at which the enkephalinase inhibitor acetorphan was ineffective, produced potent antinociceptive effects, comparable to that induced by 1 mg/kg i.v. morphine. In contrast, for the higher doses used (5, 10, 15 mg/kg i.v.), the effects of Kelatorphan were not more pronounced than that of acetorphan. Unlike acetorphan, Kelatorphan was found to be much more effective in arthritic than in normal rats in raising the vocalization threshold, even at the lower concentration, 2.5 mg/kg i.v.: 244% in arthritic vs 144% in normal rats. The effects of Kelatorphan were prevented by naloxone at the dose of 0.5 mg/kg i.v. The enhanced potency of Kelatorphan is discussed in relation with the increase in peptidase-sensitive dynorphin fragments in arthritic rats.
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Affiliation(s)
- V Kayser
- Unité de Recherches de Physiopharmacologie du Système Nerveux, U 161 INSERM, Paris, France
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26
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Morris BJ, Herz A. Control of opiate receptor number in vivo: simultaneous kappa-receptor down-regulation and mu-receptor up-regulation following chronic agonist/antagonist treatment. Neuroscience 1989; 29:433-42. [PMID: 2542839 DOI: 10.1016/0306-4522(89)90070-5] [Citation(s) in RCA: 45] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
While it is well established that opiate receptors up-regulate following chronic antagonist treatment in vivo, possible down-regulation following chronic agonist treatment remains controversial. In this study, rats received a continuous seven-day infusion of bremazocine, an opioid drug suggested to be a potent agonist at kappa receptors and an antagonist at mu and delta receptors. Opiate receptor binding was assessed in both cryostat sections and homogenates of rat brain, under conditions selective for mu, delta and kappa sites. Data from both sections and homogenates showed an increase in the capacity of mu binding sites following chronic bremazocine treatment, suggesting that up-regulation of mu receptors had occurred, and that residual ligand from the in vivo treatment had largely been removed. A significant decrease in kappa binding was observed in sections, and experiments using homogenates demonstrated a dramatic loss of high-affinity kappa binding, with an increase in low-affinity binding. There was no apparent alteration in binding to delta receptors. No significant changes were observed following acute injection of bremazocine. Quantitative light-microscopic autoradiography confirmed the results of the binding experiments, and showed that the magnitude of these effects varied between different brain regions. No decrease in kappa binding was seen following chronic administration of the partial kappa agonist nalorphine, indicating that high agonist intrinsic activity is necessary for down-regulation to occur. In addition, chronic co-administration of bremazocine with the partial agonist/antagonist diprenorphine did not cause a significant decrease in kappa binding, implying that diprenorphine can antagonize the down-regulatory effect. These results provide evidence that bremazocine possesses different degrees of intrinsic activity at mu, delta and kappa receptors. They demonstrate that, at least in the case of kappa sites, opiate receptors do show down-regulation following chronic agonist treatment in vivo.
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Affiliation(s)
- B J Morris
- Department of Neuropharmacology, Max-Planck-Institut für Psychiatrie, Planegg-Martinsried, F.R.G
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27
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Takahashi O, Traub RJ, Ruda MA. Demonstration of calcitonin gene-related peptide immunoreactive axons contacting dynorphin A(1-8) immunoreactive spinal neurons in a rat model of peripheral inflammation and hyperalgesia. Brain Res 1988; 475:168-72. [PMID: 2905620 DOI: 10.1016/0006-8993(88)90213-2] [Citation(s) in RCA: 45] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
In a rat model of peripheral inflammation and hyperalgesia, dynorphin A(1-8)-like immunoreactive (DYN-LIr) spinal neurons were examined for contacts from calcitonin gene-related peptide-like immunoreactive (CGRP-LIr) varicosities using a double-label PAP method. Ipsilateral to the inflammation, CGRP-LIr varicosities contacted both dendrites and somata of DYN-LIr neurons in lumbar laminae I, II and V. Few such contacts were found on the contralateral side. The results suggest that opioid neurons which exhibit a dynamic change in dynorphin associated with inflammation, represent a subpopulation of neurons that receive contacts from presumptive nociceptive primary afferents.
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Affiliation(s)
- O Takahashi
- Neurobiology and Anesthesiology Branch, National Institute of Dental Research, Bethesda, MD 20892
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28
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Shaikh MB, Shaikh AB, Siegel A. Opioid peptides within the midbrain periaqueductal gray suppress affective defense behavior in the cat. Peptides 1988; 9:999-1004. [PMID: 3244568 DOI: 10.1016/0196-9781(88)90080-0] [Citation(s) in RCA: 27] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
The effects of the methionine-enkephalin analog [D-Ala2-Met5]-enkephalinamide (DAME) upon the threshold for affective defense behavior were determined following microinjections placed into midbrain periaqueductal gray sites from which this response was elicited. Affective defense behavior was elicited by electrical stimulation through a cannula electrode situated in the dorsal aspect of the midbrain periaqueductal gray. Dose-response curves characterizing the effects of DAME upon affective defense behavior were determined utilizing the following doses: 0.25, 0.5 and 1.0 microgram in 0.5 microliter saline, pH = 7.4 or vehicle control (saline). Response thresholds were tested 10-30, 30-60, 60-90, 120-150, 180-210, 1440-1470 and 2880-2910 min postinjection. The results obtained indicated that injections of DAME at a dose of 1.0 microgram/0.5 microliter produced significant, long duration elevations in affective defense thresholds, lasting up to 1440-1470 min postinjection. Lower doses of DAME (0.25 and 0.5 microgram/0.5 microliter) also resulted in significant increases in affective defense thresholds, but these effects were of shorter durations (60-90 and 120-150 min) postinjection, respectively. The suppressive effects of DAME were blocked when animals were pretreated with naloxone (10 micrograms/0.5 microliter) microinjected into the same midbrain periaqueductal gray site into which 0.25 microgram DAME was injected and affective defense behavior was elicited.
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Affiliation(s)
- M B Shaikh
- Department of Neurosciences, New Jersey Medical School, Newark 07103
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