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Luessen DJ, Conn PJ. Allosteric Modulators of Metabotropic Glutamate Receptors as Novel Therapeutics for Neuropsychiatric Disease. Pharmacol Rev 2022; 74:630-661. [PMID: 35710132 PMCID: PMC9553119 DOI: 10.1124/pharmrev.121.000540] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Metabotropic glutamate (mGlu) receptors, a family of G-protein-coupled receptors, have been identified as novel therapeutic targets based on extensive research supporting their diverse contributions to cell signaling and physiology throughout the nervous system and important roles in regulating complex behaviors, such as cognition, reward, and movement. Thus, targeting mGlu receptors may be a promising strategy for the treatment of several brain disorders. Ongoing advances in the discovery of subtype-selective allosteric modulators for mGlu receptors has provided an unprecedented opportunity for highly specific modulation of signaling by individual mGlu receptor subtypes in the brain by targeting sites distinct from orthosteric or endogenous ligand binding sites on mGlu receptors. These pharmacological agents provide the unparalleled opportunity to selectively regulate neuronal excitability, synaptic transmission, and subsequent behavioral output pertinent to many brain disorders. Here, we review preclinical and clinical evidence supporting the utility of mGlu receptor allosteric modulators as novel therapeutic approaches to treat neuropsychiatric diseases, such as schizophrenia, substance use disorders, and stress-related disorders.
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Hámor PU, Schwendt M. Metabotropic Glutamate Receptor Trafficking and its Role in Drug-Induced Neurobehavioral Plasticity. Brain Plast 2021; 7:61-76. [PMID: 34868874 PMCID: PMC8609495 DOI: 10.3233/bpl-210120] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/06/2021] [Indexed: 12/18/2022] Open
Abstract
Glutamate is the major excitatory neurotransmitter in the mammalian central nervous system that guides developmental and experience-dependent changes in many cellular substrates and brain circuits, through the process collectively referred to as neurobehavioral plasticity. Regulation of cell surface expression and membrane trafficking of glutamate receptors represents an important mechanism that assures optimal excitatory transmission, and at the same time, also allows for fine-tuning neuronal responses to glutamate. On the other hand, there is growing evidence implicating dysregulated glutamate receptor trafficking in the pathophysiology of several neuropsychiatric disorders. This review provides up-to-date information on the molecular determinants regulating trafficking and surface expression of metabotropic glutamate (mGlu) receptors in the rodent and human brain and discusses the role of mGluR trafficking in maladaptive synaptic plasticity produced by addictive drugs. As substantial evidence links glutamatergic dysfunction to the progression and the severity of drug addiction, advances in our understanding of mGluR trafficking may provide opportunities for the development of novel pharmacotherapies of addiction and other neuropsychiatric disorders.
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Affiliation(s)
- Peter U. Hámor
- Department of Psychology, University of Florida, Gainesville, FL, USA
- Center for Addiction Research and Education, University of Florida, Gainesville, FL, USA
| | - Marek Schwendt
- Department of Psychology, University of Florida, Gainesville, FL, USA
- Center for Addiction Research and Education, University of Florida, Gainesville, FL, USA
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3
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Cocaine use disorder: A look at metabotropic glutamate receptors and glutamate transporters. Pharmacol Ther 2021; 221:107797. [DOI: 10.1016/j.pharmthera.2020.107797] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2019] [Accepted: 11/04/2020] [Indexed: 01/08/2023]
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Hammad AM, Alasmari F, Althobaiti YS, Sari Y. Modulatory effects of Ampicillin/Sulbactam on glial glutamate transporters and metabotropic glutamate receptor 1 as well as reinstatement to cocaine-seeking behavior. Behav Brain Res 2017. [PMID: 28624317 DOI: 10.1016/j.bbr.2017.06.017] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Glutamatergic system has an important role in cocaine-seeking behavior. Studies have reported that chronic exposure to cocaine induces downregulation of glutamate transporter-1 (GLT-1) and cystine/glutamate exchanger (xCT) in the central reward brain regions. Ceftriaxone, a β-lactam antibiotic, restored GLT-1 expression and consequently reduced cue-induced reinstatement of cocaine-seeking behavior. In this study, we investigated the reinstatement to cocaine (20mg/kg, i.p.) seeking behavior using a conditioned place preference (CPP) paradigm in male alcohol-preferring (P) rats. In addition, we investigated the effects of Ampicillin/Sulbactam (AMP/SUL) (200mg/kg, i.p.), a β-lactam antibiotic, on cocaine-induced reinstatement. We also investigated the effects of AMP/SUL on the expression of glial glutamate transporters and metabotropic glutamate receptor 1 (mGluR1) in the nucleus accumbens (NAc) core and shell and the dorsomedial prefrontal cortex (dmPFC). We found that AMP/SUL treatment reduced cocaine-triggered reinstatement. This effect was associated with a decrease in locomotor activity. Moreover, GLT-1 and xCT were downregulated in the NAc core and shell, but not in the dmPFC, following cocaine-primed reinstatement. However, cocaine exposure increased the expression of mGluR1 in the NAc core, but not in the NAc shell or dmPFC. Importantly, AMP/SUL treatment normalized GLT-1 and xCT expression in the NAc core and shell; however, the drug normalized mGluR1 expression in the NAc core only. Additionally, AMP/SUL increased the expression of GLT-1 and xCT in the dmPFC as compared to the water naïve group. These findings demonstrated that glial glutamate transporters and mGluR1 in the mesocorticolimbic area could be potential therapeutic targets for the attenuation of reinstatement to cocaine-seeking behavior.
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Affiliation(s)
- Alaa M Hammad
- Department of Pharmacology and Experimental Therapeutics, College of Pharmacy and Pharmaceutical Sciences, University of Toledo, Toledo, OH, USA
| | - Fawaz Alasmari
- Department of Pharmacology and Experimental Therapeutics, College of Pharmacy and Pharmaceutical Sciences, University of Toledo, Toledo, OH, USA
| | - Yusuf S Althobaiti
- Department of Pharmacology and Experimental Therapeutics, College of Pharmacy and Pharmaceutical Sciences, University of Toledo, Toledo, OH, USA
| | - Youssef Sari
- Department of Pharmacology and Experimental Therapeutics, College of Pharmacy and Pharmaceutical Sciences, University of Toledo, Toledo, OH, USA.
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mGlu1 receptor as a drug target for treatment of substance use disorders: time to gather stones together? Psychopharmacology (Berl) 2017; 234:1333-1345. [PMID: 28285325 DOI: 10.1007/s00213-017-4581-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/16/2016] [Accepted: 02/21/2017] [Indexed: 10/20/2022]
Abstract
Modulation of the mGlu1 receptor was repeatedly shown to inhibit various phenomena associated with exposure to abused drugs. Efficacy in preclinical models was observed with both positive and negative allosteric modulators (PAMs and NAMs, respectively) using essentially non-overlapping sets of experimental methods. Taken together, these data indicate that the mGlu1 receptor certainly plays a significant role in the plasticity triggered by the exposure to abused drugs and is involved in the maintenance of drug-seeking and drug-taking behaviors. Understanding whether modulation of the mGlu1 receptor activity can also affect drug-seeking and drug-taking in humans could have a significant impact on the future development of medications in this field. We argue that the mGlu1 receptor NAMs have a significant value as potential tools for human experimental pharmacology that could help to validate methods used in preclinical research. Compared with the PAMs, the mGlu1 receptor NAMs appear to be better candidates for this role due to the following: (1) a number of highly potent, selective, and chemically diverse mGlu1 receptor NAMs to choose from; (2) availability of high-quality PET ligands to monitor target exposure; and (3) a rich pharmacological profile with a number of effects that can complement anti-addictive action (e.g., anxiolytic/antidepressant) and may also serve as additional pharmacodynamic readouts during the preclinical-to-clinical translation. We believe that the mGlu1 receptor NAMs have a significant value as potential tools for human experimental pharmacology that could help to validate methods used in preclinical research.
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Scofield MD, Heinsbroek JA, Gipson CD, Kupchik YM, Spencer S, Smith ACW, Roberts-Wolfe D, Kalivas PW. The Nucleus Accumbens: Mechanisms of Addiction across Drug Classes Reflect the Importance of Glutamate Homeostasis. Pharmacol Rev 2017; 68:816-71. [PMID: 27363441 DOI: 10.1124/pr.116.012484] [Citation(s) in RCA: 358] [Impact Index Per Article: 51.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The nucleus accumbens is a major input structure of the basal ganglia and integrates information from cortical and limbic structures to mediate goal-directed behaviors. Chronic exposure to several classes of drugs of abuse disrupts plasticity in this region, allowing drug-associated cues to engender a pathologic motivation for drug seeking. A number of alterations in glutamatergic transmission occur within the nucleus accumbens after withdrawal from chronic drug exposure. These drug-induced neuroadaptations serve as the molecular basis for relapse vulnerability. In this review, we focus on the role that glutamate signal transduction in the nucleus accumbens plays in addiction-related behaviors. First, we explore the nucleus accumbens, including the cell types and neuronal populations present as well as afferent and efferent connections. Next we discuss rodent models of addiction and assess the viability of these models for testing candidate pharmacotherapies for the prevention of relapse. Then we provide a review of the literature describing how synaptic plasticity in the accumbens is altered after exposure to drugs of abuse and withdrawal and also how pharmacological manipulation of glutamate systems in the accumbens can inhibit drug seeking in the laboratory setting. Finally, we examine results from clinical trials in which pharmacotherapies designed to manipulate glutamate systems have been effective in treating relapse in human patients. Further elucidation of how drugs of abuse alter glutamatergic plasticity within the accumbens will be necessary for the development of new therapeutics for the treatment of addiction across all classes of addictive substances.
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Affiliation(s)
- M D Scofield
- Department of Neuroscience, Medical University of South Carolina, Charleston, South Carolina (M.D.S., J.A.H., S.S., D.R.-W., P.W.K.); Department of Psychology, Arizona State University, Tempe, Arizona (C.D.G.); Department of Neuroscience, Hebrew University, Jerusalem, Israel (Y.M.K.); and Department of Pharmacology and Systems Therapeutics, Icahn School of Medicine at Mount Sinai, New York, New York (A.C.W.S.)
| | - J A Heinsbroek
- Department of Neuroscience, Medical University of South Carolina, Charleston, South Carolina (M.D.S., J.A.H., S.S., D.R.-W., P.W.K.); Department of Psychology, Arizona State University, Tempe, Arizona (C.D.G.); Department of Neuroscience, Hebrew University, Jerusalem, Israel (Y.M.K.); and Department of Pharmacology and Systems Therapeutics, Icahn School of Medicine at Mount Sinai, New York, New York (A.C.W.S.)
| | - C D Gipson
- Department of Neuroscience, Medical University of South Carolina, Charleston, South Carolina (M.D.S., J.A.H., S.S., D.R.-W., P.W.K.); Department of Psychology, Arizona State University, Tempe, Arizona (C.D.G.); Department of Neuroscience, Hebrew University, Jerusalem, Israel (Y.M.K.); and Department of Pharmacology and Systems Therapeutics, Icahn School of Medicine at Mount Sinai, New York, New York (A.C.W.S.)
| | - Y M Kupchik
- Department of Neuroscience, Medical University of South Carolina, Charleston, South Carolina (M.D.S., J.A.H., S.S., D.R.-W., P.W.K.); Department of Psychology, Arizona State University, Tempe, Arizona (C.D.G.); Department of Neuroscience, Hebrew University, Jerusalem, Israel (Y.M.K.); and Department of Pharmacology and Systems Therapeutics, Icahn School of Medicine at Mount Sinai, New York, New York (A.C.W.S.)
| | - S Spencer
- Department of Neuroscience, Medical University of South Carolina, Charleston, South Carolina (M.D.S., J.A.H., S.S., D.R.-W., P.W.K.); Department of Psychology, Arizona State University, Tempe, Arizona (C.D.G.); Department of Neuroscience, Hebrew University, Jerusalem, Israel (Y.M.K.); and Department of Pharmacology and Systems Therapeutics, Icahn School of Medicine at Mount Sinai, New York, New York (A.C.W.S.)
| | - A C W Smith
- Department of Neuroscience, Medical University of South Carolina, Charleston, South Carolina (M.D.S., J.A.H., S.S., D.R.-W., P.W.K.); Department of Psychology, Arizona State University, Tempe, Arizona (C.D.G.); Department of Neuroscience, Hebrew University, Jerusalem, Israel (Y.M.K.); and Department of Pharmacology and Systems Therapeutics, Icahn School of Medicine at Mount Sinai, New York, New York (A.C.W.S.)
| | - D Roberts-Wolfe
- Department of Neuroscience, Medical University of South Carolina, Charleston, South Carolina (M.D.S., J.A.H., S.S., D.R.-W., P.W.K.); Department of Psychology, Arizona State University, Tempe, Arizona (C.D.G.); Department of Neuroscience, Hebrew University, Jerusalem, Israel (Y.M.K.); and Department of Pharmacology and Systems Therapeutics, Icahn School of Medicine at Mount Sinai, New York, New York (A.C.W.S.)
| | - P W Kalivas
- Department of Neuroscience, Medical University of South Carolina, Charleston, South Carolina (M.D.S., J.A.H., S.S., D.R.-W., P.W.K.); Department of Psychology, Arizona State University, Tempe, Arizona (C.D.G.); Department of Neuroscience, Hebrew University, Jerusalem, Israel (Y.M.K.); and Department of Pharmacology and Systems Therapeutics, Icahn School of Medicine at Mount Sinai, New York, New York (A.C.W.S.)
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Metabotropic glutamate receptor 5 – a promising target in drug development and neuroimaging. Eur J Nucl Med Mol Imaging 2016; 43:1151-70. [DOI: 10.1007/s00259-015-3301-5] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2015] [Accepted: 12/22/2015] [Indexed: 10/22/2022]
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Sukhanov I, Caffino L, Efimova EV, Espinoza S, Sotnikova TD, Cervo L, Fumagalli F, Gainetdinov RR. Increased context-dependent conditioning to amphetamine in mice lacking TAAR1. Pharmacol Res 2016; 103:206-14. [DOI: 10.1016/j.phrs.2015.11.002] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/13/2015] [Revised: 11/05/2015] [Accepted: 11/05/2015] [Indexed: 11/29/2022]
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Jenda M, Gawel K, Marszalek M, Komsta L, Kotlinska JH. AMN082, a metabotropic glutamate receptor 7 allosteric agonist, attenuates locomotor sensitization and cross-sensitization induced by cocaine and morphine in mice. Prog Neuropsychopharmacol Biol Psychiatry 2015; 57:166-75. [PMID: 25448778 DOI: 10.1016/j.pnpbp.2014.11.004] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/09/2014] [Revised: 10/29/2014] [Accepted: 11/06/2014] [Indexed: 10/24/2022]
Abstract
Previous studies have indicated that metabotropic glutamate receptors 7 (mGluR7s) are involved in drug addiction. However, the role of these receptors in drug-induced behavioral sensitization is unknown. The aim of the present study was to determine whether systemic injection of AMN082, a selective mGluR7 allosteric agonist, reduces the cocaine- and morphine-induced hyperactivity and the development and expression of locomotor sensitization, and also affects the reciprocal cross-sensitization to the stimulant effect of cocaine and morphine in mice. AMN082 (1.25-10.0 mg/kg, i.p.) did not have an impact on locomotion of naive mice and did not affect the acute cocaine- or morphine-induced hyperactivity, except the dose of 10 mg/kg that suppressed the locomotor effect of both drugs. Repeated exposure to cocaine or morphine (10 mg/kg, 5× every 3 days) gradually increased locomotion during induction of sensitization and after 4 (cocaine) or 7 day (morphine) withdrawal phase when challenged with cocaine (10 mg/kg, i.p.) or morphine (10 mg/kg, i.p.) on day 17 or 20, respectively. Pretreatment of animals with the lower doses of AMN082 (1.25-5.0 mg/kg, i.p.), 30 min before every cocaine or morphine injection during repeated drug administration or before cocaine or morphine challenge, dose-dependently attenuated the development, as well as the expression of cocaine or morphine locomotor sensitization. AMN082 also inhibited the reciprocal cross-sensitization between these drugs. Prior to administration of MMPIP (10 mg/kg, i.p.), a selective mGluR7 antagonist reversed the inhibitory effect of AMN082 on the development or expression of cocaine or morphine sensitization. These data indicate that AMN082 attenuated the development and expression of cocaine and morphine sensitization, and the reciprocal cross-sensitization via a mechanism that involves mGluR7s. Thus, AMN082 might have therapeutic implications not only in the treatment of cocaine or opioid addiction but also in the treatment of cocaine/opioid polydrug-abusers.
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Affiliation(s)
- M Jenda
- Department of Pharmacology and Pharmacodynamics, Medical University, Lublin, Poland
| | - K Gawel
- Department of Pharmacology and Pharmacodynamics, Medical University, Lublin, Poland
| | - M Marszalek
- Department of Pharmacology and Pharmacodynamics, Medical University, Lublin, Poland
| | - L Komsta
- Department of Medicinal Chemistry, Medical University, Lublin, Poland
| | - J H Kotlinska
- Department of Pharmacology and Pharmacodynamics, Medical University, Lublin, Poland.
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Bird MK, Lohmann P, West B, Brown RM, Kirchhoff J, Raymond CR, Lawrence AJ. The mGlu5 receptor regulates extinction of cocaine-driven behaviours. Drug Alcohol Depend 2014; 137:83-9. [PMID: 24576814 DOI: 10.1016/j.drugalcdep.2014.01.017] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/30/2013] [Revised: 01/07/2014] [Accepted: 01/13/2014] [Indexed: 11/24/2022]
Abstract
BACKGROUND There is extensive evidence implicating the metabotropic glutamate 5 (mGlu5) receptor in aspects of addiction-related behaviours. METHODS Here, we used a well-characterized line of mGlu5-deficient mice to further examine the role of this receptor in cocaine-driven behaviours. We confirmed the previously reported deficit in hippocampal long-term potentiation and associated spatial learning impairment. RESULTS Despite a spatial learning deficit, mGlu5-deficient mice developed and maintained a conditioned place preference to cocaine, suggesting cocaine reward and Pavlovian conditioning are intact in these animals. Notably, however, mGlu5-deficient mice exhibited a marked deficit in the extinction of a cocaine-conditioned place preference compared to wild type littermates. Moreover, in a fixed ratio operant intravenous self-administration paradigm, both genotypes showed similar responding for cocaine over two different doses, while mGlu5-deficient mice displayed enhanced responding on a progressive ratio schedule. In addition, cue-induced drug-seeking after abstinence was exaggerated in mGlu5-deficient mice. CONCLUSION Collectively, these findings suggest that while the mGlu5 receptor may be involved in mediating the rewarding effects of cocaine, it appears necessary for the extinction of cocaine-driven behaviours.
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Affiliation(s)
- Michael K Bird
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, Australia
| | - Peter Lohmann
- The John Curtin School of Medical Research & Eccles Institute of Neuroscience, Australian National University, Canberra, Australia
| | - Billy West
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, Australia
| | - Robyn M Brown
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, Australia; Medical University of South Carolina, Charleston, SC, USA
| | - Jeppe Kirchhoff
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, Australia
| | - Clarke R Raymond
- The John Curtin School of Medical Research & Eccles Institute of Neuroscience, Australian National University, Canberra, Australia
| | - Andrew J Lawrence
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, Australia.
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Synaptic depression via mGluR1 positive allosteric modulation suppresses cue-induced cocaine craving. Nat Neurosci 2013; 17:73-80. [PMID: 24270186 PMCID: PMC3971923 DOI: 10.1038/nn.3590] [Citation(s) in RCA: 107] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2013] [Accepted: 10/31/2013] [Indexed: 01/25/2023]
Abstract
Cue-induced cocaine craving is a major cause of relapse in abstinent addicts. In rats, cue-induced craving progressively intensifies (incubates) during withdrawal from extended-access cocaine self-administration. After ~1 month of withdrawal, incubated craving is mediated by Ca2+-permeable AMPARs (CP-AMPARs) that accumulate in the nucleus accumbens (NAc). We found that decreased mGluR1 surface expression in the NAc precedes and enables CP-AMPAR accumulation. Thus, restoring mGluR1 tone by administering repeated injections of an mGluR1 positive allosteric modulator (PAM) prevented CP-AMPAR accumulation and incubation, whereas blocking mGluR1 transmission at even earlier withdrawal times accelerated CP-AMPAR accumulation. In studies conducted after prolonged withdrawal, when CP-AMPAR levels and cue-induced craving are high, we found that systemic administration of an mGluR1 PAM attenuated the expression of incubated craving by reducing CP-AMPAR transmission in the NAc to control levels. These results demonstrate a strategy whereby recovering addicts could use a systemically active compound to protect against cue-induced relapse.
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Keck TM, Yang HJ, Bi GH, Huang Y, Zhang HY, Srivastava R, Gardner EL, Newman AH, Xi ZX. Fenobam sulfate inhibits cocaine-taking and cocaine-seeking behavior in rats: implications for addiction treatment in humans. Psychopharmacology (Berl) 2013; 229:253-65. [PMID: 23615919 PMCID: PMC4191672 DOI: 10.1007/s00213-013-3106-9] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/23/2012] [Accepted: 03/30/2013] [Indexed: 12/14/2022]
Abstract
RATIONALE The metabotropic glutamate receptor subtype 5 (mGluR5) has been reported to be critically involved in drug reward and addiction. Because the mGluR5 negative allosteric modulators (NAMs) 2-methyl-6-(phenylethynyl)pyridine (MPEP) and 3-((2-methyl-1,3-thiazol-4-yl)ethynyl)pyridine (MTEP) significantly inhibit addictivelike behaviors of cocaine and other drugs of abuse in experimental animals, it has been suggested that mGluR5 NAMs may have translational potential for treatment of addiction in humans. However, neither MPEP nor MTEP have been evaluated in humans due to their off-target actions and rapid metabolism. OBJECTIVES Herein, we evaluate a potential candidate for translational addiction research: a new sulfate salt formulation of fenobam, a selective mGluR5 NAM that has been investigated in humans. RESULTS In rats, fenobam sulfate had superior pharmacokinetics compared to the free base, with improved maximal plasma concentration (C max) and longer half life. Oral (p.o.) administration of fenobam sulfate (30 or 60 mg/kg) inhibited intravenous (i.v.) cocaine self-administration, cocaine-induced reinstatement of drug-seeking behavior, and cocaine-associated cue-induced cocaine-seeking behavior in rats. Fenobam sulfate also inhibited p.o. sucrose self-administration and sucrose-induced reinstatement of sucrose-seeking behavior, but had no effect on locomotion. CONCLUSIONS This study provides additional support for the role of mGluR5 signaling in cocaine addiction and suggests that fenobam sulfate may have translational potential in medication development for the treatment of cocaine addiction in humans.
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Affiliation(s)
- Thomas M. Keck
- Medicinal Chemistry Section, Molecular Targets and Medications Discovery Branch, Intramural Research Program, National Institute on Drug Abuse, NIH, DHHS, Baltimore, MD, USA 21224
| | - Hong-Ju Yang
- Neuropsychopharmacology Section, Chemical Biology Research Branch, Intramural Research Program, National Institute on Drug Abuse, NIH, DHHS, Baltimore, MD, USA 21224
| | - Guo-Hua Bi
- Neuropsychopharmacology Section, Chemical Biology Research Branch, Intramural Research Program, National Institute on Drug Abuse, NIH, DHHS, Baltimore, MD, USA 21224
| | - Yong Huang
- Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, San Francisco, CA, USA 94143
| | - Hai-Ying Zhang
- Neuropsychopharmacology Section, Chemical Biology Research Branch, Intramural Research Program, National Institute on Drug Abuse, NIH, DHHS, Baltimore, MD, USA 21224
| | - Ratika Srivastava
- Neuropsychopharmacology Section, Chemical Biology Research Branch, Intramural Research Program, National Institute on Drug Abuse, NIH, DHHS, Baltimore, MD, USA 21224
| | - Eliot L. Gardner
- Neuropsychopharmacology Section, Chemical Biology Research Branch, Intramural Research Program, National Institute on Drug Abuse, NIH, DHHS, Baltimore, MD, USA 21224
| | - Amy Hauck Newman
- Medicinal Chemistry Section, Molecular Targets and Medications Discovery Branch, Intramural Research Program, National Institute on Drug Abuse, NIH, DHHS, Baltimore, MD, USA 21224
- Corresponding authors: Z.-X. Xi – Phone: (443) 740-2517. Fax: (443) 740-2781. ; A. H. Newman – Phone: (443) 740-2887. Fax: (443) 740-2111.
| | - Zheng-Xiong Xi
- Neuropsychopharmacology Section, Chemical Biology Research Branch, Intramural Research Program, National Institute on Drug Abuse, NIH, DHHS, Baltimore, MD, USA 21224
- Corresponding authors: Z.-X. Xi – Phone: (443) 740-2517. Fax: (443) 740-2781. ; A. H. Newman – Phone: (443) 740-2887. Fax: (443) 740-2111.
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Herrold AA, Voigt RM, Napier TC. mGluR5 is necessary for maintenance of methamphetamine-induced associative learning. Eur Neuropsychopharmacol 2013; 23:691-6. [PMID: 22732517 PMCID: PMC3473109 DOI: 10.1016/j.euroneuro.2012.05.014] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/25/2011] [Revised: 05/10/2012] [Accepted: 05/29/2012] [Indexed: 11/30/2022]
Abstract
Conditioned place preference (CPP) reflects the significance of contextual cues that are associated with rewarding effects of abused drugs such as methamphetamine (Meth). Glutamate neurotransmission is augmented following exposure to stimulants and associated cues. Activation of group I metabotropic glutamate receptors (mGluR) is critical for the acquisition and expression of stimulant-induced CPP. We hypothesized that the maintenance of Meth-induced CPP would also require activated mGluR, and that the role of mGluR1 vs. mGluR5 group I subtypes may differ. To test this hypothesis, negative allosteric modulators (NAMs) of these receptors were administered following the development of Meth-induced CPP. NAMs exert their functional effects by displacing agonist from agonist-occupied receptors, thus NAMs selectively target brain regions with glutamate release. Conditioning with Meth every other day for six days resulted in significant preference for the Meth-paired compartment. Two once-daily injections of the mGluR1 NAM, JNJ16259685 (0.3mg/kg, i.p.) or its vehicle on days 13 and 14 after Meth-conditioning did not influence the maintenance of Meth-induced CPP; however, administration of the mGluR5 NAMs MTEP (3mg/kg, i.p.) and MPEP (30 mg/kg, i.p.) inhibited maintenance processes necessary for CPP to be expressed. These findings suggest a subtype-specific role of mGluR5 receptors in the maintenance of place preference memory and potential of mGluR5 NAMs as a useful target for Meth addiction therapy.
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Affiliation(s)
- A A Herrold
- Department of Pharmacology and Center for Compulsive Behavior and Addiction, Rush University Medical Center, Chicago, IL 60612, USA
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Herrold AA, Persons AL, Napier TC. Cellular distribution of AMPA receptor subunits and mGlu5 following acute and repeated administration of morphine or methamphetamine. J Neurochem 2013; 126:503-17. [PMID: 23711322 DOI: 10.1111/jnc.12323] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2013] [Revised: 05/09/2013] [Accepted: 05/14/2013] [Indexed: 01/14/2023]
Abstract
Ionotropic AMPA receptors (AMPAR) and metabotropic glutamate group I subtype 5 receptors (mGlu5) mediate neuronal and behavioral effects of abused drugs. mGlu5 stimulation increases expression of striatal-enriched tyrosine phosphatase isoform 61 (STEP61 ) which internalizes AMPARs. We determined the rat brain profile of these proteins using two different classes of abused drugs, opiates, and stimulants. STEP61 levels, and cellular distribution/expression of AMPAR subunits (GluA1, GluA2) and mGlu5, were evaluated via a protein cross-linking assay in medial prefrontal cortex (mPFC), nucleus accumbens (NAc), and ventral pallidum (VP) harvested 1 day after acute, or fourteen days after repeated morphine (8 mg/kg) or methamphetamine (1 mg/kg) (treatments producing behavioral sensitization). Acute morphine decreased GluA1 and GluA2 surface expression in mPFC and GluA1 in NAc. Fourteen days after repeated morphine or methamphetamine, mGlu5 surface expression increased in VP. In mPFC, mGlu5 were unaltered; however, after methamphetamine, STEP61 levels decreased and GluA2 surface expression increased. Pre-treatment with a mGlu5-selective negative allosteric modulator, blocked methamphetamine-induced behavioral sensitization and changes in mPFC GluA2 and STEP61 . These data reveal (i) region-specific distinctions in glutamate receptor trafficking between acute and repeated treatments of morphine and methamphetamine, and (ii) that mGlu5 is necessary for methamphetamine-induced alterations in mPFC GluA2 and STEP61 .
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Affiliation(s)
- Amy A Herrold
- Laboratory of Origin, Department of Pharmacology, Center for Compulsive Behavior and Addiction, Rush University Medical Center, Chicago, Illinois 60612, USA
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Metabotropic glutamate receptor I (mGluR1) antagonism impairs cocaine-induced conditioned place preference via inhibition of protein synthesis. Neuropsychopharmacology 2013; 38:1308-21. [PMID: 23348064 PMCID: PMC3656374 DOI: 10.1038/npp.2013.29] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Antagonism of group I metabotropic glutamate receptors (mGluR1 and mGluR5) reduces behavioral effects of drugs of abuse, including cocaine. However, the underlying mechanisms remain poorly understood. Activation of mGluR5 increases protein synthesis at synapses. Although mGluR5-induced excessive protein synthesis has been implicated in the pathology of fragile X syndrome, it remains unknown whether group I mGluR-mediated protein synthesis is involved in any behavioral effects of drugs of abuse. We report that group I mGluR agonist DHPG induced more pronounced initial depression of inhibitory postsynaptic currents (IPSCs) followed by modest long-term depression (I-LTD) in dopamine neurons of rat ventral tegmental area (VTA) through the activation of mGluR1. The early component of DHPG-induced depression of IPSCs was mediated by the cannabinoid CB1 receptors, while DHPG-induced I-LTD was dependent on protein synthesis. Western blotting analysis indicates that mGluR1 was coupled to extracellular signal-regulated kinase (ERK) and mammalian target of rapamycin (mTOR) signaling pathways to increase translation. We also show that cocaine conditioning activated translation machinery in the VTA via an mGluR1-dependent mechanism. Furthermore, intra-VTA microinjections of mGluR1 antagonist JNJ16259685 and protein synthesis inhibitor cycloheximide significantly attenuated or blocked the acquisition of cocaine-induced conditioned place preference (CPP) and activation of translation elongation factors. Taken together, these results suggest that mGluR1 antagonism inhibits de novo protein synthesis; this effect may block the formation of cocaine-cue associations and thus provide a mechanism for the reduction in CPP to cocaine.
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Adaptations in AMPA receptor transmission in the nucleus accumbens contributing to incubation of cocaine craving. Neuropharmacology 2013; 76 Pt B:287-300. [PMID: 23727437 DOI: 10.1016/j.neuropharm.2013.04.061] [Citation(s) in RCA: 101] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2013] [Revised: 04/29/2013] [Accepted: 04/30/2013] [Indexed: 12/23/2022]
Abstract
Cue-induced cocaine craving in rodents intensifies or "incubates" during the first months of withdrawal from long access cocaine self-administration. This incubation phenomenon is relevant to human users who achieve abstinence but exhibit persistent vulnerability to cue-induced relapse. It is well established that incubation of cocaine craving involves complex neuronal circuits. Here we will focus on neuroadaptations in the nucleus accumbens (NAc), a region of convergence for pathways that control cocaine seeking. A key adaptation is a delayed (~3-4 weeks) accumulation of Ca(2+)-permeable AMPAR receptors (CP-AMPARs) in synapses on medium spiny neurons (MSN) of the NAc. These CP-AMPARs mediate the expression of incubation after prolonged withdrawal, although different mechanisms must be responsible during the first weeks of withdrawal, prior to CP-AMPAR accumulation. The cascade of events leading to CP-AMPAR accumulation is still unclear. However, several candidate mechanisms have been identified. First, mGluR1 has been shown to negatively regulate CP-AMPAR levels in NAc synapses, and it is possible that a withdrawal-dependent decrease in this effect may help explain CP-AMPAR accumulation during incubation. Second, an increase in phosphorylation of GluA1 subunits (at the protein kinase A site) within extrasynaptic homomeric GluA1 receptors (CP-AMPARs) may promote their synaptic insertion and oppose their removal. Finally, elevation of brain-derived neurotrophic factor (BDNF) levels in the NAc may contribute to maintenance of incubation after months of withdrawal, although incubation-related increases in BDNF accumulation do not account for CP-AMPAR accumulation. Receptors and pathways that negatively regulate incubation, such as mGluR1, are promising targets for the development of therapeutic strategies to help recovering addicts maintain abstinence. This article is part of a Special Issue entitled 'NIDA 40th Anniversary Issue'.
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Kufahl PR, Nemirovsky NE, Watterson LR, Zautra N, Olive MF. Positive or negative allosteric modulation of metabotropic glutamate receptor 5 (mGluR5) does not alter expression of behavioral sensitization to methamphetamine. F1000Res 2013; 2:84. [PMID: 24358885 PMCID: PMC3814922 DOI: 10.12688/f1000research.2-84.v1] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 03/01/2013] [Indexed: 01/29/2023] Open
Abstract
We investigated the role of metabotropic glutamate receptor type 5 (mGluR5) in methamphetamine-induced behavioral sensitization. The mGluR5 positive allosteric modulator (3-cyano-N-(1,3-diphenyl-1H-pyrazol-5-yl) benzamide (CDPPB) and negative allosteric modulator fenobam were tested in separate experiments. Sprague-Dawley rats were repeatedly injected with 1 mg/kg methamphetamine or saline, and then given a locomotor challenge test using a dose of 0.5 mg/kg methamphetamine. Prior to the challenge test session, rats were injected with CDPPB, fenobam, or a vehicle. Doses from previous studies showed reduced drug-conditioned behavior; however in this study neither CDPPB nor fenobam pretreatment resulted in an altered expression of behavioral sensitization, indicating a lack of mGluR5 involvement in sensitized methamphetamine-induced locomotion. Additionally, the high dose (30 mg/kg) of fenobam resulted in decreased methamphetamine-induced locomotion in rats regardless of drug exposure history, which suggests evidence of nonspecific behavioral inhibition.
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Affiliation(s)
- Peter R Kufahl
- Department of Psychology, Arizona State University, Tempe, AZ, 85287-1104, USA
| | - Natali E Nemirovsky
- Department of Psychology, Arizona State University, Tempe, AZ, 85287-1104, USA
| | - Lucas R Watterson
- Department of Psychology, Arizona State University, Tempe, AZ, 85287-1104, USA
| | - Nicholas Zautra
- Department of Psychology, Arizona State University, Tempe, AZ, 85287-1104, USA
| | - M Foster Olive
- Department of Psychology, Arizona State University, Tempe, AZ, 85287-1104, USA
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Loweth JA, Tseng KY, Wolf ME. Using metabotropic glutamate receptors to modulate cocaine's synaptic and behavioral effects: mGluR1 finds a niche. Curr Opin Neurobiol 2013; 23:500-6. [PMID: 23385114 DOI: 10.1016/j.conb.2013.01.009] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2012] [Revised: 01/10/2013] [Accepted: 01/11/2013] [Indexed: 11/29/2022]
Abstract
Group I metabotropic glutamate receptors (mGluR) are important modulators of excitatory synaptic transmission and therefore potential targets for drug development. In several brain regions (ventral tegmental area (VTA), cerebellum, and amygdala), stimulation of mGluR1 selectively inhibits synaptic transmission mediated by calcium-permeable AMPA receptors (CP-AMPARs) and thus produces synaptic depression. The same relationship has now been demonstrated in the nucleus accumbens (NAc), a region that is critical for cocaine craving. CP-AMPAR levels in NAc synapses are normally low, but they increase after prolonged withdrawal from extended-access cocaine self-administration (SA). These CP-AMPARs mediate the intensified ('incubated') cue-induced cocaine craving observed under these conditions. Therefore, activation of mGluR1 with positive allosteric modulators (PAM) may reduce cue-induced relapse in abstinent cocaine addicts.
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Affiliation(s)
- Jessica A Loweth
- Department of Neuroscience, Rosalind Franklin University of Medicine, USA
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Parkitna JR, Sikora M, Gołda S, Gołembiowska K, Bystrowska B, Engblom D, Bilbao A, Przewlocki R. Novelty-seeking behaviors and the escalation of alcohol drinking after abstinence in mice are controlled by metabotropic glutamate receptor 5 on neurons expressing dopamine d1 receptors. Biol Psychiatry 2013; 73:263-70. [PMID: 22902169 DOI: 10.1016/j.biopsych.2012.07.019] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/18/2012] [Revised: 06/15/2012] [Accepted: 07/05/2012] [Indexed: 12/28/2022]
Abstract
BACKGROUND Novel experiences activate the brain's reward system in a manner similar to drugs of abuse, and high levels of novelty-seeking and sensation-seeking behavior have been associated with increased susceptibility to alcohol and drug abuse. Here, we show that metabotropic glutamate receptor 5 (mGluR5) signaling on dopaminoceptive neurons is necessary for both novelty-seeking behavior and the abstinence-induced escalation of alcohol drinking. METHODS Mice harboring a transgene expressing microRNA hairpins against mGluR5 messenger RNA under the control of the D1 dopamine receptor gene promoter (mGluR5(KD-D1)) were tested in a battery of behavioral tests measuring learning abilities, anxiety levels, reactions to novelty, operant sensation seeking, and alcohol sensitivity. In addition, we have developed a method to assess long-term patterns of alcohol drinking in mice housed in groups using the IntelliCage system. RESULTS mGluR5(KD-D1) mice showed no behavioral deficits and exhibited normal anxiety-like behaviors and learning abilities. However, mGluR5(KD-D1) animals showed reduced locomotor activity when placed in a novel environment, and exhibited decreased interaction with a novel object. Moreover, unlike control animals, mutant mice did not perform instrumental responses under the operant sensation-seeking paradigm, although they learned to respond for food normally. When mGluR5(KD-D1) mice were provided access to alcohol, they showed similar patterns of consumption as wild-type animals. However, mutant mice did not escalate their alcohol consumption after a period of forced abstinence, but control mice almost doubled their intake. CONCLUSIONS These data identify mGluR5 receptors on D1-expressing neurons as a common molecular substrate of novelty-seeking behaviors and behaviors associated with alcohol abuse.
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Affiliation(s)
- Jan Rodriguez Parkitna
- Department of Molecular Neuropharmacology, Institute of Pharmacology of the Polish Academy of Sciences, Krakow, Poland
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Hovelsø N, Sotty F, Montezinho LP, Pinheiro PS, Herrik KF, Mørk A. Therapeutic potential of metabotropic glutamate receptor modulators. Curr Neuropharmacol 2012; 10:12-48. [PMID: 22942876 PMCID: PMC3286844 DOI: 10.2174/157015912799362805] [Citation(s) in RCA: 73] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2010] [Revised: 01/10/2011] [Accepted: 03/04/2011] [Indexed: 12/21/2022] Open
Abstract
Glutamate is the main excitatory neurotransmitter in the central nervous system (CNS) and is a major player in complex brain functions. Glutamatergic transmission is primarily mediated by ionotropic glutamate receptors, which include NMDA, AMPA and kainate receptors. However, glutamate exerts modulatory actions through a family of metabotropic G-protein-coupled glutamate receptors (mGluRs). Dysfunctions of glutamatergic neurotransmission have been implicated in the etiology of several diseases. Therefore, pharmacological modulation of ionotropic glutamate receptors has been widely investigated as a potential therapeutic strategy for the treatment of several disorders associated with glutamatergic dysfunction. However, blockade of ionotropic glutamate receptors might be accompanied by severe side effects due to their vital role in many important physiological functions. A different strategy aimed at pharmacologically interfering with mGluR function has recently gained interest. Many subtype selective agonists and antagonists have been identified and widely used in preclinical studies as an attempt to elucidate the role of specific mGluRs subtypes in glutamatergic transmission. These studies have allowed linkage between specific subtypes and various physiological functions and more importantly to pathological states. This article reviews the currently available knowledge regarding the therapeutic potential of targeting mGluRs in the treatment of several CNS disorders, including schizophrenia, addiction, major depressive disorder and anxiety, Fragile X Syndrome, Parkinson’s disease, Alzheimer’s disease and pain.
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Affiliation(s)
- N Hovelsø
- Department of Neurophysiology, H. Lundbeck A/S, Ottiliavej 9, 2500 Copenhagen-Valby, Denmark
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21
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Achat-Mendes C, Platt DM, Spealman RD. Antagonism of metabotropic glutamate 1 receptors attenuates behavioral effects of cocaine and methamphetamine in squirrel monkeys. J Pharmacol Exp Ther 2012; 343:214-24. [PMID: 22815535 DOI: 10.1124/jpet.112.196295] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Within the group I family of metabotropic glutamate receptors (mGluRs), substantial evidence points to a role for mGluR5 mechanisms in cocaine's abuse-related behavioral effects, but less is understood about the contribution of mGluR1, which also belongs to the group I mGluR family. The selective mGluR1 antagonist JNJ16259685 [(3,4-dihydro-2H-pyrano-[2,3-b]quinolin-7-yl)-(cis-4-methoxycyclohexyl)-methanone] was used to investigate the role of mGluR1 in the behavioral effects of cocaine and methamphetamine. In drug discrimination experiments, squirrel monkeys were trained to discriminate cocaine from saline by using a two-lever, food-reinforced operant procedure. JNJ16259685 (0.56 mg/kg) pretreatments significantly attenuated cocaine's discriminative stimulus effects and the cocaine-like discriminative stimulus effects of methamphetamine. In monkeys trained to self-administer cocaine or methamphetamine under a second-order schedule of intravenous drug injection, JNJ16259685 (0.56 mg/kg) significantly reduced drug-reinforced responding, resulting in a downward displacement of dose-response functions. In reinstatement studies, intravenous priming with cocaine accompanied by restoration of a cocaine-paired stimulus reinstated extinguished cocaine-seeking behavior, which was significantly attenuated by JNJ16259685 (0.56 mg/kg). Finally, in experiments involving food rather than drug self-administration, cocaine and methamphetamine increased the rate of responding, and the rate-increasing effects of both psychostimulants were significantly attenuated by JNJ16259685 (0.3 mg/kg). At the doses tested, JNJ16259685 did not significantly suppress food-reinforced behavior (drug discrimination or fixed-interval schedule of food delivery), but did significantly reduce species-typical locomotor activity in observational studies. To the extent that the psychostimulant-antagonist effects of JNJ16259685 are independent of motor function suppression, further research is warranted to investigate other mGluR1 antagonists for potential therapeutic value in psychostimulant abuse.
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Affiliation(s)
- Cindy Achat-Mendes
- Division of Neuroscience, New England Primate Research Center, Harvard Medical School, Southborough, MA 01772, USA.
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22
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Impact of mGluR5 during amphetamine-induced hyperactivity and conditioned hyperactivity in differentially reared rats. Psychopharmacology (Berl) 2012; 221:227-37. [PMID: 22139452 DOI: 10.1007/s00213-011-2565-0] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/31/2011] [Accepted: 10/28/2011] [Indexed: 12/23/2022]
Abstract
RATIONALE 3-((2-Methyl-1,3-thiazol-4-yl)ethynyl)pyridine hydrochloride (MTEP) is a metabotropic glutamate receptor 5 (mGluR5) antagonist that may alter drug sensitivity in differentially reared rats due to its involvement in the psychostimulant reward pathway and plasticity. OBJECTIVES The purpose of this study was to assess the effects of MTEP on acute amphetamine-induced hyperactivity, conditioned hyperactivity, and sensitization. METHODS Rats were reared in an enriched (EC), isolated (IC), or standard (SC) condition after which rats were either administered MTEP (1.0 mg/kg, ip) or saline prior to an acute (0.5 or 1.0 mg/kg, sc) or repeated (0.3 mg/kg, sc) amphetamine exposure. Rats undergoing repeated amphetamine exposure were administered MTEP prior to conditioned hyperactivity and sensitization tests. RESULTS EC and SC rats administered with MTEP prior to acute amphetamine demonstrated attenuated amphetamine-induced locomotor activity compared to controls, while IC rats administered MTEP following repeated amphetamine exposure demonstrated attenuated amphetamine-induced locomotor activity. Interestingly, MTEP treatment only altered conditioned hyperactivity in EC rats, as MTEP pretreatment resulted in conditioned hyperactivity in EC rats while conditioned hyperactivity was not observed in EC rats pretreated with saline. CONCLUSIONS Glutamatergic pathways are altered during differential rearing, which differentially alters the role of mGluR5 in EC, IC, and SC rats when administered psychostimulant acutely versus repeatedly. These findings suggest that differential rearing alters glutamatergic function, which reduces sensitivity to psychostimulants.
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Cleva RM, Olive MF. Metabotropic glutamate receptors and drug addiction. ACTA ACUST UNITED AC 2012; 1:281-295. [DOI: 10.1002/wmts.18] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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Schmidt K, Krishnan B, Xia Y, Sun A, Orozco-Cabal L, Pollandt S, Centeno M, Genzer K, Gallagher JP, Shinnick-Gallagher P, Liu J. Cocaine withdrawal reduces group I mGluR-mediated long-term potentiation via decreased GABAergic transmission in the amygdala. Eur J Neurosci 2011; 34:177-89. [PMID: 21749491 DOI: 10.1111/j.1460-9568.2011.07769.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Cocaine relapse can occur when cocaine-associated environmental cues induce craving. Conditioned place preference (CPP) is a behavioral paradigm modeling the association between cocaine exposure and environmental cues. The amygdala is involved in cocaine cue associations with the basolateral amygdala (BLA) and central amygdala (CeA) acting differentially in cue-induced relapse. Activation of metabotropic glutamate receptors induces synaptic plasticity, the mechanism of which is thought to underlie learning, memory and drug-cue associations. The goal of this study was to examine the neural alterations in responses to group I metabotropic glutamate receptor (mGluR) agonists in the BLA to lateral capsula of CeA (BLA-CeLc) pathway in slices from rats exposed to cocaine-CPP conditioning and withdrawn for 14 days. mGluR1, but not mGluR5, agonist-induced long-term potentiation (mGluR1-LTP) in the BLA-CeLc pathway was reduced in rats withdrawal from cocaine for 2 and 14 days, and exhibited an altered concentration response to picrotoxin. Cocaine withdrawal also reduced γ-aminobutyric acid (GABA)ergic synaptic inhibition in CeLc neurons. Blocking cannabinoid receptor 1 (CB(1) ) reduced mGluR1-LTP in the saline-treated but not cocaine-withdrawn group. Response to CB(1) but not CB(2) agonist was altered after cocaine. Additionally, increasing endocannabinoid (eCB) levels abolished mGluR1-LTP in the saline but not cocaine-withdrawn group. However, CB(1) and CB(2) protein levels were increased in the amygdala of cocaine-withdrawn rats while mGluR1 and mGluR5 remained unchanged. These data suggested that the mechanisms underlying the diminished mGluR1-LTP in cocaine-withdrawn rats involve an altered GABAergic synaptic inhibition mediated by modulation of downstream eCB signaling. These changes may ultimately result in potentiated responses to environmental cues that would bias behavior toward drug-seeking.
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Affiliation(s)
- Kady Schmidt
- Department of Pharmacology and Toxicology, University of Texas Medical Branch at Galveston, Galveston, TX, USA
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Duncan JR, Lawrence AJ. The role of metabotropic glutamate receptors in addiction: evidence from preclinical models. Pharmacol Biochem Behav 2011; 100:811-24. [PMID: 21443897 DOI: 10.1016/j.pbb.2011.03.015] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/30/2010] [Revised: 02/21/2011] [Accepted: 03/16/2011] [Indexed: 11/25/2022]
Abstract
Addiction is a chronic disorder characterised by repeated bouts of drug taking, abstinence and relapse. The addicted state may be in part due to drug-induced neuroadaptations in the mesocorticolimbic and corticostriatal pathways. Recently focus has been on the role of aberrant glutamate transmission and its contribution to the hierarchical control over these systems. This review will expand our current knowledge of the most recent advances that have been made in preclinical animal models that provide evidence that implicate metabotropic glutamate receptors (mGluRs) in contributing to the neuroadaptations pertinent to addiction, as well as the role of Homer proteins in regulating these responses. The recent discovery of receptor mosaics will be discussed which add an additional dimension to the complexity of understanding the mechanism of glutamate mediated behaviours. Finally this review introduces a new area related to glutamatergic responses, namely microRNAs, that may become pivotal in directing our future understanding of how to best target intervention strategies to prevent addictive behaviours.
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Affiliation(s)
- Jhodie R Duncan
- Florey Neuroscience Institutes, University of Melbourne, Parkville, Vic., 3010, Australia.
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Characterization of the selective mGluR1 antagonist, JNJ16259685, in rodent models of movement and coordination. Pharmacol Biochem Behav 2011; 98:181-7. [DOI: 10.1016/j.pbb.2010.11.018] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/22/2010] [Revised: 11/22/2010] [Accepted: 11/23/2010] [Indexed: 11/23/2022]
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Uys JD, Reissner KJ. Glutamatergic Neuroplasticity in Cocaine Addiction. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2011; 98:367-400. [DOI: 10.1016/b978-0-12-385506-0.00009-0] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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28
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Li X, Li J, Gardner EL, Xi ZX. Activation of mGluR7s inhibits cocaine-induced reinstatement of drug-seeking behavior by a nucleus accumbens glutamate-mGluR2/3 mechanism in rats. J Neurochem 2010; 114:1368-80. [PMID: 20534005 DOI: 10.1111/j.1471-4159.2010.06851.x] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The metabotropic glutamate receptor 7 (mGluR7) has been reported to be involved in cocaine and alcohol self-administration. However, the role of mGluR7 in relapse to drug seeking is unknown. Using a rat relapse model, we found that systemic administration of AMN082, a selective mGluR7 allosteric agonist, dose-dependently inhibits cocaine-induced reinstatement of drug-seeking behavior. Intracranial microinjections of AMN082 into the nucleus accumbens (NAc) or ventral pallidum, but not the dorsal striatum, also inhibited cocaine-primed reinstatement, an effect that was blocked by local co-administration of MMPIP, a selective mGluR7 antagonist. In vivo microdialysis demonstrated that cocaine priming significantly increased extracellular dopamine in the NAc, ventral pallidum and dorsal striatum, while increasing extracellular glutamate in the NAc only. AMN082 alone failed to alter extracellular dopamine, but produced a slow-onset long-lasting increase in extracellular glutamate in the NAc only. Pre-treatment with AMN082 dose-dependently blocked both cocaine-enhanced NAc glutamate and cocaine-induced reinstatement, an effect that was blocked by MMPIP or LY341497 (a selective mGluR2/3 antagonist). These data suggest that mGluR7 activation inhibits cocaine-induced reinstatement of drug-seeking behavior by a glutamate-mGluR2/3 mechanism in the NAc. The present findings support the potential use of mGluR7 agonists for the treatment of cocaine addiction.
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Affiliation(s)
- Xia Li
- Intramural Research Program, National Institute on Drug Abuse, National Institutes of Health, DHHS, Baltimore, Maryland 21224, USA
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29
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Mitrano D, Pare JF, Smith Y. Ultrastructural relationships between cortical, thalamic, and amygdala glutamatergic inputs and group I metabotropic glutamate receptors in the rat accumbens. J Comp Neurol 2010; 518:1315-29. [PMID: 20151362 PMCID: PMC3895817 DOI: 10.1002/cne.22277] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Changes in glutamatergic transmission in the nucleus accumbens play a key role in mediating reward-related behaviors and addiction to psychostimulants. Glutamatergic inputs to the accumbens originate from multiple sources, including the prefrontal cortex, basolateral amygdala, and midline thalamus. The group I metabotropic glutamate receptors (mGluRs) are found throughout the core and shell of the nucleus accumbens, but their localization and function at specific glutamatergic synapses remain unknown. To further characterize the substrate that underlies group I mGluR functions in the accumbens, we combined anterograde tract tracing method with electron microscopy immunocytochemistry to study the ultrastructural relationships between specific glutamatergic afferents and mGluR1a- or mGluR5-containing neurons in the rat nucleus accumbens. Although cortical, thalamic, and amygdala glutamatergic terminals contact both mGluR1a- and mGluR5-immunoreactive dendrites and spines in the shell and core of the accumbens, they do so to varying degrees. Overall, glutamatergic terminals contact mGluR1a-positive spines about 30% of the time, whereas they form synapses twice as frequently with mGluR5-labeled spines. At the subsynaptic level, mGluR5 is more frequently expressed perisynaptically and closer to the edges of glutamatergic axospinous synapses than mGluR1a, suggesting a differential degree of activation of the two group I mGluRs by transmitter spillover from glutamatergic synapses in the rat accumbens. These results lay the foundation for a deeper understanding of group I mGluR-mediated effects in the ventral striatum, and their potential therapeutic benefits in drug addiction and other neuropsychiatric changes in reward-related behaviors.
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Affiliation(s)
- D.A. Mitrano
- Yerkes National Primate Research Center, Emory University, Atlanta, Georgia 30322
- Department of Human Genetics, Emory University, Atlanta, Georgia 30322
| | - J.-F. Pare
- Yerkes National Primate Research Center, Emory University, Atlanta, Georgia 30322
| | - Y. Smith
- Yerkes National Primate Research Center, Emory University, Atlanta, Georgia 30322
- Department of Neurology, Emory University, Atlanta, Georgia 30322
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Schmidt HD, Pierce RC. Cocaine-induced neuroadaptations in glutamate transmission: potential therapeutic targets for craving and addiction. Ann N Y Acad Sci 2010; 1187:35-75. [PMID: 20201846 DOI: 10.1111/j.1749-6632.2009.05144.x] [Citation(s) in RCA: 164] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
A growing body of evidence indicates that repeated exposure to cocaine leads to profound changes in glutamate transmission in limbic nuclei, particularly the nucleus accumbens. This review focuses on preclinical studies of cocaine-induced behavioral plasticity, including behavioral sensitization, self-administration, and the reinstatement of cocaine seeking. Behavioral, pharmacological, neurochemical, electrophysiological, biochemical, and molecular biological changes associated with cocaine-induced plasticity in glutamate systems are reviewed. The ultimate goal of these lines of research is to identify novel targets for the development of therapies for cocaine craving and addiction. Therefore, we also outline the progress and prospects of glutamate modulators for the treatment of cocaine addiction.
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Affiliation(s)
- Heath D Schmidt
- Department of Psychiatry, Center for Neurobiology and Behavior, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, USA
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McIldowie MJ, Gandy MN, Skelton BW, Brotchie JM, Koutsantonis GA, Spackman MA, Piggott MJ. Physical and crystallographic characterisation of the mGlu5 antagonist MTEP and its monohydrochloride. J Pharm Sci 2010; 99:234-45. [DOI: 10.1002/jps.21823] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Xie X, Ramirez DR, Lasseter HC, Fuchs RA. Effects of mGluR1 antagonism in the dorsal hippocampus on drug context-induced reinstatement of cocaine-seeking behavior in rats. Psychopharmacology (Berl) 2010; 208:1-11. [PMID: 19847405 PMCID: PMC4381836 DOI: 10.1007/s00213-009-1700-7] [Citation(s) in RCA: 75] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/20/2009] [Accepted: 10/05/2009] [Indexed: 10/20/2022]
Abstract
RATIONALE The functional integrity of the dorsal hippocampus (DH) is necessary for drug context-induced reinstatement of cocaine seeking. However, the neuropharmacological mechanisms of this phenomenon are poorly understood. OBJECTIVES Given the known significance of group I metabotropic glutamate receptors (mGluRs), including the mGluR1 subtype, in drug-induced behaviors, the present study was designed to evaluate the contribution of mGluR1s in the DH to drug context-induced reinstatement of extinguished cocaine-seeking behavior. METHODS Sprague-Dawley rats were trained to lever press for unsignaled cocaine infusions in a distinct environmental context (cocaine-paired context) followed by extinction training in a distinctly different environmental context (extinction context). Using a counterbalanced partial within-subjects testing design, rats were re-exposed to the cocaine-paired context or the extinction context while cocaine-seeking behavior (nonreinforced active lever pressing) was assessed. Prior to each test session, rats received bilateral microinfusions of the highly potent mGluR1-selective antagonist JNJ16259685 (0.6, 30, or 120 pg/0.5 microl per hemisphere) or vehicle into the DH or the overlying somatosensory cortex trunk region (SStr; anatomical control). RESULTS Intra-DH, but not intra-SStr, JNJ16259685 infusions dose dependently attenuated drug context-induced reinstatement of cocaine seeking relative to vehicle treatment, without attenuating instrumental behavior in the extinction context, general motor activity, or food-reinforced instrumental behavior in control experiments. CONCLUSIONS Stimulation of mGluR1s in the DH is necessary for incentive motivational and/or memory processes that contribute to drug context-induced cocaine-seeking behavior. These findings indicate that the mGluR1 is an interesting target from an addiction treatment perspective.
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Affiliation(s)
- Xiaohu Xie
- Department of Psychology, University of North Carolina, Chapel Hill, NC, USA
| | - Donna R. Ramirez
- Department of Psychology, University of North Carolina, Chapel Hill, NC, USA
| | - Heather C. Lasseter
- Department of Psychology, University of North Carolina, Chapel Hill, NC, USA
| | - Rita A. Fuchs
- Department of Psychology, University of North Carolina, Chapel Hill, NC, USA
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Kotlinska J, Bochenski M. Pretreatment with group I metabotropic glutamate receptors antagonists attenuates lethality induced by acute cocaine overdose and expression of sensitization to hyperlocomotor effect of cocaine in mice. Neurotox Res 2009; 19:23-30. [PMID: 19936864 DOI: 10.1007/s12640-009-9136-8] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2009] [Revised: 10/12/2009] [Accepted: 11/10/2009] [Indexed: 10/20/2022]
Abstract
Cocaine abuse and dependence is a worldwide health problem. However, there are no currently approved medications to reduce cocaine abuse/relapse and toxicity. The aim of the present study was to test, whether group I metabotropic glutamate receptors (mGluRs) antagonists (mGluR1 and mGluR5) differentially regulate toxic versus behavioral effects of cocaine, both phenomena relevant to the psychopathology of cocaine addiction in humans. In the present study, we assessed the impact of mGluR1 antagonist-EMQMCM and mGluR5 antagonist-MTEP on the cocaine-induced lethality and the expression of sensitization to hyperlocomotor effect of cocaine in mice. Our study indicated that EMQMCM and MTEP, both substances at the doses of 5 and 10 mg/kg (but not 2.5 mg/kg), decreased cocaine-induced lethality produced by 75 mg/kg of cocaine, which was given acutely. The effect of EMQMCM was dose-dependent, and this compound at the dose of 10 mg/kg almost completely abolished the lethality induced by cocaine. MTEP reduced this cocaine effect at the doses of 5 and 10 mg/kg, equally. Furthermore, EMQMCM (1.25-5 mg/kg) at the doses of 2.5 and 5.0 mg/kg, and MTEP (2.5-10 mg/kg) only at the highest dose of 10 mg/kg, significantly reduced the expression of cocaine-induced (10 mg/kg) behavioral sensitization. Our results suggest that stimulation of mGluR1 and mGluR5 is involved in lethal effect of cocaine overdose and cocaine seeking behavior evaluated in behavioral sensitization test. However, the participation of mGluR1 in these cocaine effects seems to be dominant. Therefore, antagonists showing preferences towards mGluR1 might be useful in therapy of cocaine toxicity and abuse.
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Affiliation(s)
- Jolanta Kotlinska
- Department of Pharmacology and Pharmacodynamics, Medical University, Staszica 4, 20-081 Lublin, Poland.
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Olive MF. Metabotropic glutamate receptor ligands as potential therapeutics for addiction. ACTA ACUST UNITED AC 2009; 2:83-98. [PMID: 19630739 DOI: 10.2174/1874473710902010083] [Citation(s) in RCA: 162] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
There is now compelling evidence that the excitatory amino acid neurotransmitter glutamate plays a pivotal role in drug addiction and alcoholism. As a result, there has been increasing interest in developing glutamate-based therapies for the treatment of addictive disorders. Receptors for glutamate are primarily divided into two classes: ionotropic glutamate receptors (iGluRs) that mediate fast excitatory glutamate transmission, and metabotropic glutamate receptors (mGluRs), which are G-protein coupled receptors that mediate slower, modulatory glutamate transmission. Most iGluR antagonists, while showing some efficacy in animal models of addiction, exhibit serious side effects when tested in humans. mGluR ligands, on the other hand, which have been advanced to testing in clinical trials for various medical conditions, have demonstrated the ability to reduce drug reward, reinforcement, and relapse-like behaviors in animal studies. mGluR ligands that have been shown to be primarily effective are Group I (mGluR1 and mGluR5) negative allosteric modulators and Group II (mGluR2 and mGluR3) orthosteric presynaptic autoreceptor agonists. In this review, we will summarize findings from animal studies suggesting that these mGluR ligands may be of potential benefit in reducing on-going drug self-administration and may aid in the prevention of relapse. The neuroanatomical distribution of mGluR1, mGluR2/3, and mGluR5 receptors and the pharmacological properties of Group I negative allosteric modulators and Group II agonists will also be overviewed. Finally, we will discuss the current status of mGluR ligands in human clinical trials.
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Affiliation(s)
- M Foster Olive
- Center for Drug and Alcohol Programs, Department of Psychiatry and Behavioral Sciences, Medical University of South Carolina, 67 President Street, MSC 861, Charleston, SC 29425, USA.
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Metabotropic glutamate receptor 5 (mGluR5) antagonists attenuate cocaine priming- and cue-induced reinstatement of cocaine seeking. Behav Brain Res 2009; 202:238-44. [PMID: 19463707 DOI: 10.1016/j.bbr.2009.03.039] [Citation(s) in RCA: 132] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2009] [Revised: 03/25/2009] [Accepted: 03/28/2009] [Indexed: 11/23/2022]
Abstract
Accumulating evidence suggests that metabotropic glutamate receptors (mGluRs) are involved in both cocaine reinforcement and the reinstatement of cocaine-seeking behavior. In the present experiments, rats were trained to self-administer cocaine under fixed ratio (for cocaine priming-induced reinstatement) or second-order (for cocaine cue-induced reinstatement) schedules of reinforcement. Lever pressing was then extinguished followed by a reinstatement phase where operant responding was promoted by either cocaine itself or cocaine-associated light cues. Results indicated that systemic administration of the mGluR5 antagonists 2-methyl-6-(phenylethynyl)pyridine (MPEP: 1 and 3mg/kg i.p.) or 3-((2-methyl-1,3-thiazol-4-yl)ethynyl)pyridine (MTEP: 0.1 and 1mg/kg i.p.) dose-dependently attenuated reinstatement of drug seeking induced by a systemic priming injection of 10mg/kg cocaine. Systemic administration of MTEP (0.1 and 1mg/kg i.p.) also dose-dependently attenuated cocaine cue-induced reinstatement of drug seeking. Systemic administration of neither MPEP nor MTEP influenced the reinstatement of sucrose seeking, which indicates that the effects of these compounds on cocaine seeking were reinforcer specific. Additionally, administration of MPEP (1microg/0.5microl) into the nucleus accumbens shell, a brain region that plays a critical role in cocaine seeking, attenuated cocaine priming-induced reinstatement of drug seeking. These results add to a growing literature indicating that mGluR antagonists attenuate the reinstatement of cocaine seeking. Importantly, the current findings also suggest that activation of mGluR5s specifically in the nucleus accumbens shell may promote the reinstatement of cocaine seeking.
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Subcellular and subsynaptic localization of group I metabotropic glutamate receptors in the nucleus accumbens of cocaine-treated rats. Neuroscience 2008; 154:653-66. [PMID: 18479833 DOI: 10.1016/j.neuroscience.2008.03.049] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2008] [Revised: 03/06/2008] [Accepted: 03/20/2008] [Indexed: 10/22/2022]
Abstract
There is significant pharmacological and behavioral evidence that group I metabotropic glutamate receptors (mGluR1a and mGluR5) in the nucleus accumbens play an important role in the neurochemical and pathophysiological mechanisms that underlie addiction to psychostimulants. To further address this issue, we undertook a detailed ultrastructural analysis to characterize changes in the subcellular and subsynaptic localization of mGluR1a and mGluR5 in the core and shell of nucleus accumbens following acute or chronic cocaine administration in rats. After a single cocaine injection (30 mg/kg) and 45 min withdrawal, there was a significant decrease in the proportion of plasma membrane-bound mGluR1a in accumbens shell dendrites. Similarly, the proportion of plasma membrane-bound mGluR1a was decreased in large dendrites of accumbens core neurons following chronic cocaine exposure (i.e. 1-week treatment followed by 3-week withdrawal). However, neither acute nor chronic cocaine treatments induced significant change in the localization of mGluR5 in accumbens core and shell, which is in contrast with the significant reduction of plasma membrane-bound mGluR1a and mGluR5 induced by local intra-accumbens administration of the group I mGluR agonist, (RS)-3,5-dihydroxyphenylglycine (DHPG). In conclusion, these findings demonstrate that cocaine-induced glutamate imbalance has modest effects on the trafficking of group I mGluRs in the nucleus accumbens. These results provide valuable information on the neuroadaptive mechanisms of accumbens group I mGluRs in response to cocaine administration.
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Jaeschke G, Wettstein JG, Nordquist RE, Spooren W. mGlu5 receptor antagonists and their therapeutic potential. Expert Opin Ther Pat 2008. [DOI: 10.1517/13543776.18.2.123] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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Sukhotina IA, Dravolina OA, Novitskaya Y, Zvartau EE, Danysz W, Bespalov AY. Effects of mGlu1 receptor blockade on working memory, time estimation, and impulsivity in rats. Psychopharmacology (Berl) 2008; 196:211-20. [PMID: 17909752 DOI: 10.1007/s00213-007-0953-2] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/09/2007] [Accepted: 09/17/2007] [Indexed: 12/27/2022]
Abstract
RATIONALE Metabotropic glutamate 1 (mGlu1) receptor antagonists were reported to induce cognitive deficits in several animal models using aversive learning procedures. OBJECTIVE The present study aimed to further characterize behavioral effects of mGlu1 receptor antagonists using appetitively motivated tasks that evaluate working memory, timing, and impulsivity functions. MATERIALS AND METHODS Separate groups of adult male Wistar rats were trained to perform four food-reinforced operant tasks: delayed non-matching to position (DNMTP), differential reinforcement of low rates of responding 18 s (DRL 18-s), signal duration discrimination (2-s vs 8-s bisection), and tolerance to delay of reward. Before the tests, rats were pretreated with (3-ethyl-2-methyl-quinolin-6-yl)-(4-methoxy-cyclohexyl)-methanone methanesulfonate (EMQMCM; 2.5-10 mg/kg, i.p.; JNJ16567083). RESULTS In DNMTP task, EMQMCM produced delay-dependent increases in performance accuracy so that, at 10 mg/kg dose level, percentage of correct lever choices was enhanced at 8- and 16-s delays. In DRL task, at all three tested doses, response rates were higher, and reinforcement rates were lower than under control conditions. In signal duration discrimination tasks, EMQMCM did not have any specific effects on temporal control. In tolerance to delay of reward, EMQMCM (5 and 10 mg/kg) facilitated choice of the lever associated with large reward at longer delay levels. CONCLUSIONS Blockade of mGlu1 receptors improves working memory and reduces impulsive choice at the doses that have no effects on time perception but appear to facilitate impulsive action.
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Affiliation(s)
- Irina A Sukhotina
- Laboratory of Behavioral Pharmacology, Institute of Pharmacology, Pavlov Medical University, 6/8 Leo Tolstoy Str., St. Petersburg, 197089, Russia
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Palucha A, Pilc A. Metabotropic glutamate receptor ligands as possible anxiolytic and antidepressant drugs. Pharmacol Ther 2007; 115:116-47. [PMID: 17582504 DOI: 10.1016/j.pharmthera.2007.04.007] [Citation(s) in RCA: 175] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2007] [Accepted: 04/25/2007] [Indexed: 11/18/2022]
Abstract
Depression and anxiety represent a major problem. However, the current treatment of both groups of diseases is not satisfactory. As the glutamatergic system may play an important role in pathophysiology of both depression and anxiety, we decided to discuss the recent data on possible anxiolytic and/or antidepressant effects of metabotropic glutamate (mGlu) receptor ligands. Preclinical data indicated that antagonists of group I mGlu receptors, particularly antagonists of mGlu5 receptors, produced both anxiolytic-like and antidepressant-like effects. Clinical data also demonstrated that mGlu5 receptor antagonist, fenobam, was an active anxiolytic drug. The anxiolytic effects exerted by mGlu5 receptor antagonists are profound, comparable with or stronger than those of benzodiazepines. However, the problem with the psychotomimetic activity of mGlu5 receptor antagonists and their possible influence on memory has to be further investigated. Among all mGlu receptor ligands, group II mGlu receptor agonists seem to be the drugs with the most promising therapeutic potential and a good safety profile. Animal studies showed anxiolytic-like effects of group II mGlu receptor agonists. Currently, group II mGlu receptor agonists are in phase III clinical trials for potential treatment of anxiety disorders. On the other hand, data has been accumulated, indicating that antagonists of group II mGlu receptors have an antidepressant potential. Group III mGlu receptor ligands represent the least investigated group of mGlu receptors. However, preclinical data also indicates that ligands of these receptors, both agonists and antagonists, may have an anxiolytic-like and antidepressant-like potential.
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Affiliation(s)
- Agnieszka Palucha
- Institute of Pharmacology, Polish Academy of Sciences, Smetna 12, 31-343 Kraków, Poland
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Kotlinska J, Bochenski M. Comparison of the effects of mGluR1 and mGluR5 antagonists on the expression of behavioral sensitization to the locomotor effect of morphine and the morphine withdrawal jumping in mice. Eur J Pharmacol 2006; 558:113-8. [PMID: 17222405 DOI: 10.1016/j.ejphar.2006.11.067] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2006] [Revised: 11/28/2006] [Accepted: 11/29/2006] [Indexed: 11/29/2022]
Abstract
The aim of the present study was to compare the influence of group I metabotropic glutamate receptor (mGluR) antagonists (mGluR1 and mGluR5) on the expression of sensitization to the locomotor effect of morphine. We also tested how these compounds affect the morphine withdrawal jumps in mice. In our study, the mGluR1 antagonist EMQMCM [3-ethyl-2-methyl-quinolin-6-yl-(4-methoxy-cyclohexyl)-methanone methanesulfonate] and the mGluR5 antagonist MTEP ([(2-methyl-1,3-thiazol-4-yl) ethynyl] pyridine) were used. Sensitization was induced by five intraperitoneal (i.p.) injections of morphine at the dose of 10 mg/kg, every 3 days. Morphine dependence was induced by subcutaneous (s.c.) implantation of pellets containing 37.5 mg of morphine base for three days. Our data indicate that pretreatment with EMQMCM (5, 10, 20 mg/kg) and MTEP (5, 10 mg/kg) on the challenge day, inhibited the expression of sensitization to the locomotor effect of morphine in mice. Antagonists of both subtypes of the group I mGlurs given alone, did not modify the acute locomotor effect of morphine. On the other hand, EMQMCM did not attenuate the morphine withdrawal jumps precipitated by naloxone (4 mg/kg). The results suggest that both subtypes of the group I mGluRs (mGluR1 and mGluR5) take part in the expression of morphine sensitization processes but mGluR1 is not involved in the expression of morphine withdrawal jumps in mice. These findings may have implications for the treatment of opiate addiction in future.
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Affiliation(s)
- Jolanta Kotlinska
- Department of Pharmacology and Pharmacodynamics, Medical University, Staszica 4, 20-081 Lublin, Poland.
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