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Bachtell RK, Larson TA, Winkler MC. Adenosine receptor stimulation inhibits methamphetamine-associated cue seeking. J Psychopharmacol 2023; 37:192-203. [PMID: 36629009 DOI: 10.1177/02698811221147157] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
BACKGROUND Methamphetamine (METH) is a psychostimulant drug that remains a popular and threatening drug of abuse with high abuse liability. There is no established pharmacotherapy to treat METH dependence, but evidence suggests that stimulation of adenosine receptors reduces the reinforcing properties of METH and could be a potential pharmacological target. This study examines the effects of adenosine receptor subtype stimulation on METH seeking using both a cue-induced reinstatement and cue-craving model of relapse. METHODS Male and female rats were trained to self-administer METH during daily 2-h sessions. Cue-induced reinstatement of METH seeking was evaluated after extinction training. A systemic pretreatment of an adenosine A1 receptor (A1R) or A2A receptor (A2AR) agonist was administered prior to an extinction or cue session to evaluate the effects of adenosine receptor subtype stimulation on METH seeking. The effects of a systemic pretreatment of A1R or A2AR agonists were also evaluated in a cue-craving model where the cued-seeking test was conducted after 21 days of forced home-cage abstinence without extinction training. RESULTS Cue-induced reinstatement was reduced in both male and female rats that received A1R or A2AR agonist pretreatments. Similarly, an A1R or A2AR agonist pretreatment also inhibited cue craving in both male and female rats. CONCLUSION Stimulation of either adenosine A1R or A2AR subtypes inhibits METH-seeking behavior elicited by METH-associated cues. These effects may be attributed to the ability of A1R and A2AR stimulation to disrupt cue-induced dopamine and glutamate signaling throughout the brain.
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Affiliation(s)
- Ryan K Bachtell
- Department of Psychology and Neuroscience and Center for Neuroscience, University of Colorado Boulder, Boulder, CO, USA.,Institute for Behavioral Genetics, University of Colorado Boulder, Boulder, CO, USA
| | - Tracey A Larson
- Department of Psychology and Neuroscience and Center for Neuroscience, University of Colorado Boulder, Boulder, CO, USA
| | - Madeline C Winkler
- Department of Psychology and Neuroscience and Center for Neuroscience, University of Colorado Boulder, Boulder, CO, USA
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2
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Hámor PU, Knackstedt LA, Schwendt M. The role of metabotropic glutamate receptors in neurobehavioral effects associated with methamphetamine use. INTERNATIONAL REVIEW OF NEUROBIOLOGY 2023; 168:177-219. [PMID: 36868629 DOI: 10.1016/bs.irn.2022.10.005] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Metabotropic glutamate (mGlu) receptors are expressed throughout the central nervous system and act as important regulators of drug-induced neuroplasticity and behavior. Preclinical research suggests that mGlu receptors play a critical role in a spectrum of neural and behavioral consequences arising from methamphetamine (meth) exposure. However, an overview of mGlu-dependent mechanisms linked to neurochemical, synaptic, and behavioral changes produced by meth has been lacking. This chapter provides a comprehensive review of the role of mGlu receptor subtypes (mGlu1-8) in meth-induced neural effects, such as neurotoxicity, as well as meth-associated behaviors, such as psychomotor activation, reward, reinforcement, and meth-seeking. Additionally, evidence linking altered mGlu receptor function to post-meth learning and cognitive deficits is critically evaluated. The chapter also considers the role of receptor-receptor interactions involving mGlu receptors and other neurotransmitter receptors in meth-induced neural and behavioral changes. Taken together, the literature indicates that mGlu5 regulates the neurotoxic effects of meth by attenuating hyperthermia and possibly through altering meth-induced phosphorylation of the dopamine transporter. A cohesive body of work also shows that mGlu5 antagonism (and mGlu2/3 agonism) reduce meth-seeking, though some mGlu5-blocking drugs also attenuate food-seeking. Further, evidence suggests that mGlu5 plays an important role in extinction of meth-seeking behavior. In the context of a history of meth intake, mGlu5 also co-regulates aspects of episodic memory, with mGlu5 stimulation restoring impaired memory. Based on these findings, we propose several avenues for the development of novel pharmacotherapies for Methamphetamine Use Disorder based on the selective modulation mGlu receptor subtype activity.
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Affiliation(s)
- Peter U Hámor
- Department of Psychology, University of Florida, Gainesville, FL, United States; Center for Addiction Research and Education, University of Florida, Gainesville, FL, United States; Department of Pharmacology, Weill Cornell Medicine, Cornell University, New York, NY, United States
| | - Lori A Knackstedt
- Department of Psychology, University of Florida, Gainesville, FL, United States; Center for Addiction Research and Education, University of Florida, Gainesville, FL, United States
| | - Marek Schwendt
- Department of Psychology, University of Florida, Gainesville, FL, United States; Center for Addiction Research and Education, University of Florida, Gainesville, FL, United States.
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3
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Broadhead MJ, Miles GB. A common role for astrocytes in rhythmic behaviours? Prog Neurobiol 2021; 202:102052. [PMID: 33894330 DOI: 10.1016/j.pneurobio.2021.102052] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2020] [Revised: 03/03/2021] [Accepted: 04/13/2021] [Indexed: 01/16/2023]
Abstract
Astrocytes are a functionally diverse form of glial cell involved in various aspects of nervous system infrastructure, from the metabolic and structural support of neurons to direct neuromodulation of synaptic activity. Investigating how astrocytes behave in functionally related circuits may help us understand whether there is any conserved logic to the role of astrocytes within neuronal networks. Astrocytes are implicated as key neuromodulatory cells within neural circuits that control a number of rhythmic behaviours such as breathing, locomotion and circadian sleep-wake cycles. In this review, we examine the evidence that astrocytes are directly involved in the regulation of the neural circuits underlying six different rhythmic behaviours: locomotion, breathing, chewing, gastrointestinal motility, circadian sleep-wake cycles and oscillatory feeding behaviour. We discuss how astrocytes are integrated into the neuronal networks that regulate these behaviours, and identify the potential gliotransmission signalling mechanisms involved. From reviewing the evidence of astrocytic involvement in a range of rhythmic behaviours, we reveal a heterogenous array of gliotransmission mechanisms, which help to regulate neuronal networks. However, we also observe an intriguing thread of commonality, in the form of purinergic gliotransmission, which is frequently utilised to facilitate feedback inhibition within rhythmic networks to constrain a given behaviour within its operational range.
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Affiliation(s)
- Matthew J Broadhead
- School of Psychology and Neuroscience, University of St Andrews, St Andrews, UK.
| | - Gareth B Miles
- School of Psychology and Neuroscience, University of St Andrews, St Andrews, UK
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4
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Gipson CD, Rawls S, Scofield MD, Siemsen BM, Bondy EO, Maher EE. Interactions of neuroimmune signaling and glutamate plasticity in addiction. J Neuroinflammation 2021; 18:56. [PMID: 33612110 PMCID: PMC7897396 DOI: 10.1186/s12974-021-02072-8] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2020] [Accepted: 01/05/2021] [Indexed: 02/28/2023] Open
Abstract
Chronic use of drugs of abuse affects neuroimmune signaling; however, there are still many open questions regarding the interactions between neuroimmune mechanisms and substance use disorders (SUDs). Further, chronic use of drugs of abuse can induce glutamatergic changes in the brain, but the relationship between the glutamate system and neuroimmune signaling in addiction is not well understood. Therefore, the purpose of this review is to bring into focus the role of neuroimmune signaling and its interactions with the glutamate system following chronic drug use, and how this may guide pharmacotherapeutic treatment strategies for SUDs. In this review, we first describe neuroimmune mechanisms that may be linked to aberrant glutamate signaling in addiction. We focus specifically on the nuclear factor-kappa B (NF-κB) pathway, a potentially important neuroimmune mechanism that may be a key player in driving drug-seeking behavior. We highlight the importance of astroglial-microglial crosstalk, and how this interacts with known glutamatergic dysregulations in addiction. Then, we describe the importance of studying non-neuronal cells with unprecedented precision because understanding structure-function relationships in these cells is critical in understanding their role in addiction neurobiology. Here we propose a working model of neuroimmune-glutamate interactions that underlie drug use motivation, which we argue may aid strategies for small molecule drug development to treat substance use disorders. Together, the synthesis of this review shows that interactions between glutamate and neuroimmune signaling may play an important and understudied role in addiction processes and may be critical in developing more efficacious pharmacotherapies to treat SUDs.
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Affiliation(s)
- Cassandra D Gipson
- Department of Family and Community Medicine, University of Kentucky, 741 S. Limestone, BBSRB, Room 363, Lexington, KY, 40536-0509, USA.
| | - Scott Rawls
- Department of Pharmacology, Lewis Katz School of Medicine, Temple University, Philadelphia, USA
| | - Michael D Scofield
- Department of Anesthesiology, Medical University of South Carolina, Charleston, USA
- Department of Neuroscience, Medical University of South Carolina, Charleston, USA
| | - Benjamin M Siemsen
- Department of Anesthesiology, Medical University of South Carolina, Charleston, USA
| | - Emma O Bondy
- Department of Family and Community Medicine, University of Kentucky, 741 S. Limestone, BBSRB, Room 363, Lexington, KY, 40536-0509, USA
| | - Erin E Maher
- Department of Family and Community Medicine, University of Kentucky, 741 S. Limestone, BBSRB, Room 363, Lexington, KY, 40536-0509, USA
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5
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Hámor PU, Gobin CM, Schwendt M. The role of glutamate mGlu5 and adenosine A2a receptor interactions in regulating working memory performance and persistent cocaine seeking in rats. Prog Neuropsychopharmacol Biol Psychiatry 2020; 103:109979. [PMID: 32470496 DOI: 10.1016/j.pnpbp.2020.109979] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/17/2020] [Revised: 05/19/2020] [Accepted: 05/20/2020] [Indexed: 01/17/2023]
Abstract
Cocaine use disorder (CUD) is associated with neurobehavioral deficits that are resistant to current treatments. While craving and high rates of relapse are prominent features of CUD, persistent cognitive impairments are common and linked to poorer treatment outcomes. Here we sought to develop an animal model to study post-cocaine changes in drug seeking and working memory, and to evaluate 'therapeutic' effects of combined glutamate mGlu5 and adenosine A2a receptor blockade. As mGlu5 antagonists reduce drug seeking, and A2a blockade ameliorates working memory impairment, we hypothesized that mGlu5 + A2a antagonist cocktail would reduce both cocaine relapse and post-cocaine working memory deficits. Adult male Sprague-Dawley rats were first trained and tested in an operant delayed match-to-sample (DMS) task to establish the working memory baseline, followed by 6 days of limited and 12 days of extended access cocaine self-administration. Chronic cocaine reduced working memory performance (abstinence day 30-40) and produced robust time-dependent cocaine seeking at 45-, but not 120-days of abstinence. Systemic administration of A2a antagonist KW-6002 (0.125 and 1 mg/kg) failed to rescue post-cocaine working memory deficit. It also failed to reverse working memory impairment produced by mGlu5 NAM MTEP (1 mg/kg). Finally, KW-6002 prevented the ability of MTEP to reduce cocaine seeking and increased locomotor behavior. Thus, despite mGlu5 and A2a being exclusively co-localized in the striatum and showing behavioral synergism towards reducing cocaine effects in some studies, our findings advocate against the use of mGlu5 + A2a antagonist cocktail as it may further compromise cognitive deficits and augment drug craving in CUD.
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Affiliation(s)
- Peter U Hámor
- Department of Psychology, University of Florida, FL, USA; Center for Addiction Education and Research, University of Florida, FL, USA
| | - Christina M Gobin
- Center for Addiction Education and Research, University of Florida, FL, USA; Department of Pharmacodynamics, University of Florida, FL, USA
| | - Marek Schwendt
- Department of Psychology, University of Florida, FL, USA; Center for Addiction Education and Research, University of Florida, FL, USA.
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6
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León-Navarro DA, Albasanz JL, Martín M. Functional Cross-Talk between Adenosine and Metabotropic Glutamate Receptors. Curr Neuropharmacol 2019; 17:422-437. [PMID: 29663888 PMCID: PMC6520591 DOI: 10.2174/1570159x16666180416093717] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2017] [Revised: 03/19/2018] [Accepted: 04/13/2018] [Indexed: 12/14/2022] Open
Abstract
Abstract: G-protein coupled receptors are transmembrane proteins widely expressed in cells and their transduction pathways are mediated by controlling second messenger levels through different G-protein interactions. Many of these receptors have been described as involved in the physiopathology of neurodegenerative diseases and even considered as potential targets for the design of novel therapeutic strategies. Endogenous and synthetic allosteric and orthosteric selective ligands are able to modulate GPCRs at both gene and protein expression levels and can also modify their physiological function. GPCRs that coexist in the same cells can homo- and heteromerize, therefore, modulating their function. Adenosine receptors are GPCRs which stimulate or inhibit adenylyl cyclase activity through Gi/Gs protein and are involved in the control of neurotransmitter release as glutamate. In turn, metabotropic glutamate receptors are also GPCRs which inhibit adenylyl cyclase or stimulate phospholipase C activities through Gi or Gq proteins, respectively. In recent years, evidence of crosstalk mechanisms be-tween different GPCRs have been described. The aim of the present review was to summarize the described mechanisms of interaction and crosstalking between adenosine and metabotropic glutamate receptors, mainly of group I, in both in vitro and in vivo systems, and their possible use for the design of novel ligands for the treatment of neurodegenerative diseases.
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Affiliation(s)
- David Agustín León-Navarro
- Departamento de Quimica Inorganica, Organica y Bioquimica. CRIB, Universidad de Castilla-La Mancha, Spain.,Facultad de Ciencias y Tecnologías Químicas, Avenida Camilo José Cela, 10, 13071 Ciudad Real, Spain
| | - José Luis Albasanz
- Departamento de Quimica Inorganica, Organica y Bioquimica. CRIB, Universidad de Castilla-La Mancha, Spain.,Facultad de Ciencias y Tecnologías Químicas, Avenida Camilo José Cela, 10, 13071 Ciudad Real, Spain.,Facultad de Medicina de Ciudad Real, Camino Moledores s/n. 13071 Ciudad Real, Spain
| | - Mairena Martín
- Departamento de Quimica Inorganica, Organica y Bioquimica. CRIB, Universidad de Castilla-La Mancha, Spain.,Facultad de Ciencias y Tecnologías Químicas, Avenida Camilo José Cela, 10, 13071 Ciudad Real, Spain.,Facultad de Medicina de Ciudad Real, Camino Moledores s/n. 13071 Ciudad Real, Spain
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7
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Mao LM, Wang JQ. Amphetamine-induced Conditioned Place Preference and Changes in mGlu1/5 Receptor Expression and Signaling in the Rat Medial Prefrontal Cortex. Neuroscience 2018; 400:110-119. [PMID: 30599269 DOI: 10.1016/j.neuroscience.2018.12.041] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2018] [Revised: 11/27/2018] [Accepted: 12/21/2018] [Indexed: 12/27/2022]
Abstract
The medial prefrontal cortex (mPFC) is implicated in the rewarding effect of psychostimulants, although molecular mechanisms underlying the rewarding properties of stimulants in this region are poorly understood. Group I metabotropic glutamate (mGlu) receptors (mGlu1/5 subtypes) are believed to be critical in this event. We thus in this study investigated changes in mGlu1/5 receptor expression and function in the rat mPFC in response to conditioned place preference (CPP) induced by amphetamine. Repeated amphetamine administration (2.5 mg/kg, once daily on alternate days for 10 days) induced reliable CPP. In the mPFC, surface expression of mGlu5 receptors was elevated in rats after amphetamine conditioning. mGlu5 receptors were also increased at synaptic and extrasynaptic sites in amphetamine-conditioned rats. Expression of mGlu1 receptors was stable in surface and synaptic compartments, while it was elevated in the extrasynaptic location. In mPFC neurons, the mGlu1/5 agonist-stimulated phosphoinositide signaling pathway was upregulated in its efficacy following amphetamine conditioning. The mGlu1/5 agonist-stimulated Src kinase phosphorylation was also augmented in rats treated with amphetamine. These results demonstrate the sensitivity of mPFC mGlu1/5 receptors to amphetamine-induced CPP. Amphetamine conditioning results in the upregulation of mGlu1/5 receptor expression at subcellular and/or subsynaptic levels and mGlu1/5-mediated postreceptor signaling in mPFC neurons.
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Affiliation(s)
- Li-Min Mao
- Department of Biomedical Sciences, School of Medicine, University of Missouri-Kansas City, Kansas City, MO 64108, USA
| | - John Q Wang
- Department of Biomedical Sciences, School of Medicine, University of Missouri-Kansas City, Kansas City, MO 64108, USA; Department of Anesthesiology, School of Medicine, University of Missouri-Kansas City, Kansas City, MO 64108, USA.
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8
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Lindberg D, Andres-Beck L, Jia YF, Kang S, Choi DS. Purinergic Signaling in Neuron-Astrocyte Interactions, Circadian Rhythms, and Alcohol Use Disorder. Front Physiol 2018; 9:9. [PMID: 29467662 PMCID: PMC5808134 DOI: 10.3389/fphys.2018.00009] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2017] [Accepted: 01/05/2018] [Indexed: 12/17/2022] Open
Abstract
Alcohol use disorder (AUD) is a debilitating condition marked by cyclic patterns of craving, use, and withdrawal. These pathological behaviors are mediated by multiple neurotransmitter systems utilizing glutamate, GABA, dopamine, ATP, and adenosine. In particular, purines such as ATP and adenosine have been demonstrated to alter the phase and function of the circadian clock and are reciprocally regulated by the clock itself. Importantly, chronic ethanol intake has been demonstrated to disrupt the molecular circadian clock and is associated with altered circadian patterns of activity and sleep. Moreover, ethanol has been demonstrated to disrupt purinergic signaling, while dysfunction of the purinergic system has been implicated in conditions of drug abuse such as AUD. In this review, we summarize our current knowledge regarding circadian disruption by ethanol, focusing on the reciprocal relationship that exists between oscillatory neurotransmission and the molecular circadian clock. In particular, we offer detailed explanations and hypotheses regarding the concerted regulation of purinergic signaling and circadian oscillations by neurons and astrocytes, and review the diverse mechanisms by which purinergic dysfuction may contribute to circadian disruption or alcohol abuse. Finally, we describe the mechanisms by which ethanol may disrupt or hijack endogenous circadian rhythms to induce the maladaptive behavioral patterns associated with AUD.
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Affiliation(s)
- Daniel Lindberg
- Neurobiology of Disease, Mayo Clinic College of Medicine, Rochester, MN, United States
| | - Lindsey Andres-Beck
- Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic College of Medicine, Rochester, MN, United States
| | - Yun-Fang Jia
- Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic College of Medicine, Rochester, MN, United States
| | - Seungwoo Kang
- Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic College of Medicine, Rochester, MN, United States
| | - Doo-Sup Choi
- Neurobiology of Disease, Mayo Clinic College of Medicine, Rochester, MN, United States.,Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic College of Medicine, Rochester, MN, United States.,Department of Psychiatry and Psychology, Mayo Clinic College of Medicine, Rochester, MN, United States
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9
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Perry CJ, Lawrence AJ. Hurdles in Basic Science Translation. Front Pharmacol 2017; 8:478. [PMID: 28769807 PMCID: PMC5513913 DOI: 10.3389/fphar.2017.00478] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2017] [Accepted: 07/03/2017] [Indexed: 11/13/2022] Open
Abstract
In the past century there have been incredible advances in the field of medical research, but what hinders translation of this knowledge into effective treatment for human disease? There is an increasing focus on the failure of many research breakthroughs to be translated through the clinical trial process and into medical practice. In this mini review, we will consider some of the reasons that findings in basic medical research fail to become translated through clinical trials and into basic medical practices. We focus in particular on the way that human disease is modeled, the understanding we have of how our targets behave in vivo, and also some of the issues surrounding reproducibility of basic research findings. We will also look at some of the ways that have been proposed for overcoming these issues. It appears that there needs to be a cultural shift in the way we fund, publish and recognize quality control in scientific research. Although this is a daunting proposition, we hope that with increasing awareness and focus on research translation and the hurdles that impede it, the field of medical research will continue to inform and improve medical practice across the world.
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Affiliation(s)
- Christina J Perry
- Behavioural Neuroscience Division, The Florey Institute of Neuroscience and Mental Health, ParkvilleVIC, Australia.,Florey Department of Neuroscience and Mental Health, University of Melbourne, MelbourneVIC, Australia
| | - Andrew J Lawrence
- Behavioural Neuroscience Division, The Florey Institute of Neuroscience and Mental Health, ParkvilleVIC, Australia.,Florey Department of Neuroscience and Mental Health, University of Melbourne, MelbourneVIC, Australia
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10
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The galanin-3 receptor antagonist, SNAP 37889, suppresses alcohol drinking and morphine self-administration in mice. Neuropharmacology 2017; 118:1-12. [DOI: 10.1016/j.neuropharm.2017.03.004] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2016] [Revised: 02/17/2017] [Accepted: 03/02/2017] [Indexed: 02/07/2023]
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11
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Morin N, Morissette M, Grégoire L, Di Paolo T. mGlu5, Dopamine D2 and Adenosine A2A Receptors in L-DOPA-induced Dyskinesias. Curr Neuropharmacol 2017; 14:481-93. [PMID: 26639458 PMCID: PMC4983750 DOI: 10.2174/1570159x14666151201185652] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2015] [Revised: 11/04/2015] [Accepted: 11/11/2015] [Indexed: 02/07/2023] Open
Abstract
Patients with Parkinson's disease (PD) receiving L-3,4-dihydroxyphenylalanine (L-DOPA, the gold-standard treatment for this disease) frequently develop abnormal involuntary movements, termed L-DOPA-induced dyskinesias (LID). Glutamate overactivity is well documented in PD and LID. An approach to manage LID is to add to L-DOPA specific agents to reduce dyskinesias such as metabotropic glutamate receptor (mGlu receptor) drugs. This article reviews the contribution of mGlu type 5 (mGlu5) receptors in animal models of PD. Several mGlu5 negative allosteric modulators acutely attenuate LID in 1-methyl-4-phenyl-1,2,3,6- tetrahydropyridine (MPTP) monkeys and 6-hydroxydopamine(6-OHDA)-lesioned rats. Chronic administration of mGlu5 negative allosteric modulators to MPTP monkeys and 6-OHDA rats also attenuates LID while maintaining the antiparkinsonian effect of L-DOPA. Radioligand autoradiography shows an elevation of striatal mGlu5 receptors of dyskinetic L-DOPA-treated MPTP monkeys but not in those without LID. The brain molecular correlates of the long-term effect of mGlu5 negative allosteric modulators treatments with L-DOPA attenuating development of LID was shown to extend beyond mGlu5 receptors with normalization of glutamate activity in the basal ganglia of L-DOPA-induced changes of NMDA, AMPA, mGlu2/3 receptors and VGlut2 transporter. In the basal ganglia, mGlu5 receptor negative allosteric modulators also normalize the L-DOPA-induced changes of dopamine D2receptors, their associated signaling proteins (ERK1/2 and Akt/GSK3β) and neuropeptides (preproenkephalin, preprodynorphin) as well as the adenosine A2A receptors expression. These results show in animal models of PD reduction of LID with mGlu5 negative allosteric modulation associated with normalization of glutamate, dopamine and adenosine receptors suggesting a functional link of these receptors in chronic treatment with L-DOPA.
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Affiliation(s)
| | | | | | - Thérèse Di Paolo
- Neuroscience Research Unit, Centre de recherche du CHU de Québec, 2705 Laurier Boulevard, Quebec, Qc, Canada, G1V 4G2.
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12
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Wright SR, Zanos P, Georgiou P, Yoo JH, Ledent C, Hourani SM, Kitchen I, Winsky-Sommerer R, Bailey A. A critical role of striatal A2A R-mGlu5 R interactions in modulating the psychomotor and drug-seeking effects of methamphetamine. Addict Biol 2016; 21:811-25. [PMID: 25975203 DOI: 10.1111/adb.12259] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
Addiction to psychostimulants is a major public health problem with no available treatment. Adenosine A2A receptors (A2A R) co-localize with metabotropic glutamate 5 receptors (mGlu5 R) in the striatum and functionally interact to modulate behaviours induced by addictive substances, such as alcohol. Using genetic and pharmacological antagonism of A2A R in mice, we investigated whether A2A R-mGlu5 R interaction can regulate the locomotor, stereotypic and drug-seeking effect of methamphetamine and cocaine, two drugs that exhibit distinct mechanism of action. Genetic deletion of A2A R, as well as combined administration of sub-threshold doses of the selective A2A R antagonist (SCH 58261, 0.01 mg/kg, i.p.) with the mGlu5 R antagonist, 3-((2-methyl-4-thiazolyl)ethynyl)pyridine (0.01 mg/kg, i.p.), prevented methamphetamine- but not cocaine-induced hyperactivity and stereotypic rearing behaviour. This drug combination also prevented methamphetamine-rewarding effects in a conditioned-place preference paradigm. Moreover, mGlu5 R binding was reduced in the nucleus accumbens core of A2A R knockout (KO) mice supporting an interaction between these receptors in a brain region crucial in mediating addiction processes. Chronic methamphetamine, but not cocaine administration, resulted in a significant increase in striatal mGlu5 R binding in wild-type mice, which was absent in the A2A R KO mice. These data are in support of a critical role of striatal A2A R-mGlu5 R functional interaction in mediating the ambulatory, stereotypic and reinforcing effects of methamphetamine but not cocaine-induced hyperlocomotion or stereotypy. The present study highlights a distinct and selective mechanistic role for this receptor interaction in regulating methamphetamine-induced behaviours and suggests that combined antagonism of A2A R and mGlu5 R may represent a novel therapy for methamphetamine addiction.
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Affiliation(s)
- Sherie R. Wright
- Sleep, Chronobiology and Addiction Group; School of Biosciences and Medicine; Faculty of Health and Medical Sciences; University of Surrey; UK
| | - Panos Zanos
- Sleep, Chronobiology and Addiction Group; School of Biosciences and Medicine; Faculty of Health and Medical Sciences; University of Surrey; UK
| | - Polymnia Georgiou
- Sleep, Chronobiology and Addiction Group; School of Biosciences and Medicine; Faculty of Health and Medical Sciences; University of Surrey; UK
| | - Ji-Hoon Yoo
- Sleep, Chronobiology and Addiction Group; School of Biosciences and Medicine; Faculty of Health and Medical Sciences; University of Surrey; UK
| | - Catherine Ledent
- Institut de Recherche Interdisciplinaire en Biologie Humaine et Moléculaire; Université Libre de Bruxelles; Belgium
| | - Susanna M. Hourani
- Sleep, Chronobiology and Addiction Group; School of Biosciences and Medicine; Faculty of Health and Medical Sciences; University of Surrey; UK
| | - Ian Kitchen
- Sleep, Chronobiology and Addiction Group; School of Biosciences and Medicine; Faculty of Health and Medical Sciences; University of Surrey; UK
| | - Raphaelle Winsky-Sommerer
- Sleep, Chronobiology and Addiction Group; School of Biosciences and Medicine; Faculty of Health and Medical Sciences; University of Surrey; UK
| | - Alexis Bailey
- Sleep, Chronobiology and Addiction Group; School of Biosciences and Medicine; Faculty of Health and Medical Sciences; University of Surrey; UK
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13
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Chesworth R, Brown RM, Kim JH, Ledent C, Lawrence AJ. Adenosine 2A receptors modulate reward behaviours for methamphetamine. Addict Biol 2016; 21:407-21. [PMID: 25612195 DOI: 10.1111/adb.12225] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Addiction to methamphetamine (METH) is a global health problem for which there are no approved pharmacotherapies. The adenosine 2A (A2 A ) receptor presents a potential therapeutic target for METH abuse due to its modulatory effects on striatal dopamine and glutamate transmission. Notably, A2 A receptor signalling has been implicated in the rewarding effects of alcohol, cocaine and opiates; yet, the role of this receptor in METH consumption and seeking is essentially unknown. Therefore, the current study used A2 A knockout (KO) mice to assess the role of A2 A in behaviours relevant to METH addiction. METH conditioned place preference was absent in A2 A KO mice compared with wild-type (WT) littermates. Repeated METH treatment produced locomotor sensitization in both genotypes; however, sensitization was attenuated in A2 A KO mice in a dose-related manner. METH intravenous self-administration was intact in A2 A KO mice over a range of doses and schedules of reinforcement. However, the motivation to self-administer was reduced in A2 A KO mice. Regression analysis further supported the observation that the motivation to self-administer METH was reduced in A2 A KO mice even when self-administration was similar to WT mice. Sucrose self-administration was also reduced in A2 A KO mice but only at higher schedules of reinforcement. Collectively, these data suggest that A2 A signalling is critically required to integrate rewarding and motivational properties of both METH and natural rewards.
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Affiliation(s)
- Rose Chesworth
- Behavioural Neuroscience Division; Florey Institute of Neuroscience and Mental Health; Australia
- Florey Department of Neuroscience and Mental Health; University of Melbourne; Australia
| | - Robyn M. Brown
- Behavioural Neuroscience Division; Florey Institute of Neuroscience and Mental Health; Australia
- Florey Department of Neuroscience and Mental Health; University of Melbourne; Australia
- Department of Neurosciences; Medical University of South Carolina; Charleston SC USA
| | - Jee Hyun Kim
- Behavioural Neuroscience Division; Florey Institute of Neuroscience and Mental Health; Australia
- Florey Department of Neuroscience and Mental Health; University of Melbourne; Australia
| | - Catherine Ledent
- Institut de Recherche Interdisciplinaire; Faculté de Médecine; Université de Bruxelles; Belgium
| | - Andrew J. Lawrence
- Behavioural Neuroscience Division; Florey Institute of Neuroscience and Mental Health; Australia
- Florey Department of Neuroscience and Mental Health; University of Melbourne; Australia
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14
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Gould RW, Amato RJ, Bubser M, Joffe ME, Nedelcovych MT, Thompson AD, Nickols HH, Yuh JP, Zhan X, Felts AS, Rodriguez AL, Morrison RD, Byers FW, Rook JM, Daniels JS, Niswender CM, Conn PJ, Emmitte KA, Lindsley CW, Jones CK. Partial mGlu₅ Negative Allosteric Modulators Attenuate Cocaine-Mediated Behaviors and Lack Psychotomimetic-Like Effects. Neuropsychopharmacology 2016; 41:1166-78. [PMID: 26315507 PMCID: PMC4748441 DOI: 10.1038/npp.2015.265] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/26/2015] [Revised: 08/17/2015] [Accepted: 08/21/2015] [Indexed: 11/09/2022]
Abstract
Cocaine abuse remains a public health concern for which pharmacotherapies are largely ineffective. Comorbidities between cocaine abuse, depression, and anxiety support the development of novel treatments targeting multiple symptom clusters. Selective negative allosteric modulators (NAMs) targeting the metabotropic glutamate receptor 5 (mGlu5) subtype are currently in clinical trials for the treatment of multiple neuropsychiatric disorders and have shown promise in preclinical models of substance abuse. However, complete blockade or inverse agonist activity by some full mGlu5 NAM chemotypes demonstrated adverse effects, including psychosis in humans and psychotomimetic-like effects in animals, suggesting a narrow therapeutic window. Development of partial mGlu5 NAMs, characterized by their submaximal but saturable levels of blockade, may represent a novel approach to broaden the therapeutic window. To understand potential therapeutic vs adverse effects in preclinical behavioral assays, we examined the partial mGlu5 NAMs, M-5MPEP and Br-5MPEPy, in comparison with the full mGlu5 NAM MTEP across models of addiction and psychotomimetic-like activity. M-5MPEP, Br-5MPEPy, and MTEP dose-dependently decreased cocaine self-administration and attenuated the discriminative stimulus effects of cocaine. M-5MPEP and Br-5MPEPy also demonstrated antidepressant- and anxiolytic-like activity. Dose-dependent effects of partial and full mGlu5 NAMs in these assays corresponded with increasing in vivo mGlu5 occupancy, demonstrating an orderly occupancy-to-efficacy relationship. PCP-induced hyperlocomotion was potentiated by MTEP, but not by M-5MPEP and Br-5MPEPy. Further, MTEP, but not M-5MPEP, potentiated the discriminative-stimulus effects of PCP. The present data suggest that partial mGlu5 NAM activity is sufficient to produce therapeutic effects similar to full mGlu5 NAMs, but with a broader therapeutic index.
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Affiliation(s)
- Robert W Gould
- Department of Pharmacology, Vanderbilt University Medical Center, Nashville, TN, USA.,Vanderbilt Center for Neuroscience Drug Discovery, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Russell J Amato
- Department of Pharmacology, Vanderbilt University Medical Center, Nashville, TN, USA.,Vanderbilt Center for Neuroscience Drug Discovery, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Michael Bubser
- Department of Pharmacology, Vanderbilt University Medical Center, Nashville, TN, USA.,Vanderbilt Center for Neuroscience Drug Discovery, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Max E Joffe
- Department of Pharmacology, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Michael T Nedelcovych
- Department of Pharmacology, Vanderbilt University Medical Center, Nashville, TN, USA.,Vanderbilt Center for Neuroscience Drug Discovery, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Analisa D Thompson
- Department of Pharmacology, Vanderbilt University Medical Center, Nashville, TN, USA.,Vanderbilt Center for Neuroscience Drug Discovery, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Hilary H Nickols
- Vanderbilt Center for Neuroscience Drug Discovery, Vanderbilt University Medical Center, Nashville, TN, USA.,Department of Pathology, Microbiology and Immunology, Division of Neuropathology, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Johannes P Yuh
- Department of Pharmacology, Vanderbilt University Medical Center, Nashville, TN, USA.,Vanderbilt Center for Neuroscience Drug Discovery, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Xiaoyan Zhan
- Department of Pharmacology, Vanderbilt University Medical Center, Nashville, TN, USA.,Vanderbilt Center for Neuroscience Drug Discovery, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Andrew S Felts
- Vanderbilt Center for Neuroscience Drug Discovery, Vanderbilt University Medical Center, Nashville, TN, USA.,Department of Chemistry, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Alice L Rodriguez
- Department of Pharmacology, Vanderbilt University Medical Center, Nashville, TN, USA.,Vanderbilt Center for Neuroscience Drug Discovery, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Ryan D Morrison
- Department of Pharmacology, Vanderbilt University Medical Center, Nashville, TN, USA.,Vanderbilt Center for Neuroscience Drug Discovery, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Frank W Byers
- Department of Pharmacology, Vanderbilt University Medical Center, Nashville, TN, USA.,Vanderbilt Center for Neuroscience Drug Discovery, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Jerri M Rook
- Department of Pharmacology, Vanderbilt University Medical Center, Nashville, TN, USA.,Vanderbilt Center for Neuroscience Drug Discovery, Vanderbilt University Medical Center, Nashville, TN, USA
| | - John S Daniels
- Department of Pharmacology, Vanderbilt University Medical Center, Nashville, TN, USA.,Vanderbilt Center for Neuroscience Drug Discovery, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Colleen M Niswender
- Department of Pharmacology, Vanderbilt University Medical Center, Nashville, TN, USA.,Vanderbilt Center for Neuroscience Drug Discovery, Vanderbilt University Medical Center, Nashville, TN, USA
| | - P Jeffrey Conn
- Department of Pharmacology, Vanderbilt University Medical Center, Nashville, TN, USA.,Vanderbilt Center for Neuroscience Drug Discovery, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Kyle A Emmitte
- Department of Pharmacology, Vanderbilt University Medical Center, Nashville, TN, USA.,Vanderbilt Center for Neuroscience Drug Discovery, Vanderbilt University Medical Center, Nashville, TN, USA.,Department of Chemistry, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Craig W Lindsley
- Department of Pharmacology, Vanderbilt University Medical Center, Nashville, TN, USA.,Vanderbilt Center for Neuroscience Drug Discovery, Vanderbilt University Medical Center, Nashville, TN, USA.,Department of Chemistry, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Carrie K Jones
- Department of Pharmacology, Vanderbilt University Medical Center, Nashville, TN, USA.,Vanderbilt Center for Neuroscience Drug Discovery, Vanderbilt University Medical Center, Nashville, TN, USA
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15
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Chronic administration of the methylxanthine propentofylline impairs reinstatement to cocaine by a GLT-1-dependent mechanism. Neuropsychopharmacology 2014; 39:499-506. [PMID: 23985782 PMCID: PMC3870775 DOI: 10.1038/npp.2013.223] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/26/2013] [Revised: 08/22/2013] [Accepted: 08/23/2013] [Indexed: 01/30/2023]
Abstract
In recent years, interactions between neurons and glia have been evaluated as mediators of neuropsychiatric diseases, including drug addiction. In particular, compounds that increase expression of the astroglial glutamate transporter GLT-1 (N-acetylcysteine and ceftriaxone) can decrease measures of drug seeking. However, it is unknown whether the compounds that influence broad measures of glial physiology can influence behavioral measures of drug relapse, nor is it clear whether the upregulated GLT-1 is functionally important for suppressing of drug seeking. To address these questions, we sought to determine whether the glial modulator and neuroprotective agent propentofylline (PPF) modifies drug seeking in rats using a reinstatement model of cocaine relapse. We found that 7 days of chronic (but not acute) administration of PPF significantly decreased both cue- and cocaine-induced reinstatement of cocaine seeking. We next determined whether the effect of systemic PPF on reinstatement depended upon its ability to restore expression of GLT-1 in the nucleus accumbens. PPF restored the cocaine-induced decrease in GLT-1 in the accumbens core; then, using an antisense strategy against glutamate transporter GLT-1, we found that restored transporter expression was necessary for PPF to inhibit cue-primed cocaine seeking. These findings indicate that modulating glial physiology with atypical xanthine derivatives like PPF is a potential avenue for developing new medications for cocaine abuse, and support the hypothesis that neuron-glial interactions contribute to mechanisms of psychostimulant addiction, particularly via expression and function of astroglial glutamate transporters.
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16
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Chesworth R, Brown RM, Kim JH, Lawrence AJ. The metabotropic glutamate 5 receptor modulates extinction and reinstatement of methamphetamine-seeking in mice. PLoS One 2013; 8:e68371. [PMID: 23861896 PMCID: PMC3701637 DOI: 10.1371/journal.pone.0068371] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2013] [Accepted: 05/29/2013] [Indexed: 12/12/2022] Open
Abstract
Methamphetamine (METH) is a highly addictive psychostimulant with no therapeutics registered to assist addicts in discontinuing use. Glutamatergic dysfunction has been implicated in the development and maintenance of addiction. We sought to assess the involvement of the metabotropic glutamate 5 receptor (mGlu5) in behaviours relevant to METH addiction because this receptor has been implicated in the actions of other drugs of abuse, including alcohol, cocaine and opiates. mGlu5 knockout (KO) mice were tested in intravenous self-administration, conditioned place preference and locomotor sensitization. Self-administration of sucrose was used to assess the response of KO mice to a natural reward. Acquisition and maintenance of self-administration, as well as the motivation to self-administer METH was intact in mGlu5 KO mice. Importantly, mGlu5 KO mice required more extinction sessions to extinguish the operant response for METH, and exhibited an enhanced propensity to reinstate operant responding following exposure to drug-associated cues. This phenotype was not present when KO mice were tested in an equivalent paradigm assessing operant responding for sucrose. Development of conditioned place preference and locomotor sensitization were intact in KO mice; however, conditioned hyperactivity to the context previously paired with drug was elevated in KO mice. These data demonstrate a role for mGlu5 in the extinction and reinstatement of METH-seeking, and suggests a role for mGlu5 in regulating contextual salience.
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Affiliation(s)
- Rose Chesworth
- Behavioural Neuroscience Division, Florey Institute of Neuroscience and Mental Health, Parkville, Victoria, Australia
- Florey Department of Neuroscience and Mental Health, University of Melbourne, Parkville, Victoria, Australia
| | - Robyn M. Brown
- Behavioural Neuroscience Division, Florey Institute of Neuroscience and Mental Health, Parkville, Victoria, Australia
- Florey Department of Neuroscience and Mental Health, University of Melbourne, Parkville, Victoria, Australia
- Department of Neurosciences, Medical University of South Carolina, Charleston, South Carolina, United States of America
| | - Jee Hyun Kim
- Behavioural Neuroscience Division, Florey Institute of Neuroscience and Mental Health, Parkville, Victoria, Australia
- Florey Department of Neuroscience and Mental Health, University of Melbourne, Parkville, Victoria, Australia
| | - Andrew J. Lawrence
- Behavioural Neuroscience Division, Florey Institute of Neuroscience and Mental Health, Parkville, Victoria, Australia
- Florey Department of Neuroscience and Mental Health, University of Melbourne, Parkville, Victoria, Australia
- * E-mail:
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17
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Dai SS, Wang H, Yang N, An JH, Li W, Ning YL, Zhu PF, Chen JF, Zhou YG. Plasma glutamate-modulated interaction of A2AR and mGluR5 on BMDCs aggravates traumatic brain injury-induced acute lung injury. ACTA ACUST UNITED AC 2013; 210:839-51. [PMID: 23478188 PMCID: PMC3620361 DOI: 10.1084/jem.20122196] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Activation of adenosine A2A receptor aggravates lung damage in a neurogenic mouse model of acute lung injury (ALI) but protects against nonneurogenic ALI. The bone marrow–derived cell (BMDC)–associated inflammatory response plays a key role in the development of acute lung injury (ALI). Activation of adenosine A2A receptor (A2AR) is generally considered to be antiinflammatory, inhibiting BMDC activities to protect against ALI. However, in the present study, we found that in a mouse model of neurogenic ALI induced by severe traumatic brain injury (TBI), BMDC A2AR exerted a proinflammatory effect, aggravating lung damage. This is in contrast to the antiinflammatory effect observed in the mouse oleic acid–induced ALI model (a nonneurogenic ALI model.) Moreover, the A2AR agonist CGS21680 aggravated, whereas the antagonist ZM241385 attenuated, the severe TBI-induced lung inflammatory damage in mice. Further investigation of white blood cells isolated from patients or mouse TBI models and of cultured human or mouse neutrophils demonstrated that elevated plasma glutamate after severe TBI induced interaction between A2AR and the metabotropic glutamate receptor 5 (mGluR5) to increase phospholipase C–protein kinase C signaling, which mediated the proinflammatory effect of A2AR. These results are in striking contrast to the well-known antiinflammatory and protective role of A2AR in nonneurogenic ALI and indicate different therapeutic strategies should be used for nonneurogenic and neurogenic ALI treatment when targeting A2AR.
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Affiliation(s)
- Shuang-Shuang Dai
- Department of Biochemistry and Molecular Biology, State Key Laboratory of Trauma, Burn, and Combined Injury, Third Military Medical University, Chongqing 400042, China
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18
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Brown RM, Mustafa S, Ayoub MA, Dodd PR, Pfleger KDG, Lawrence AJ. mGlu5 Receptor Functional Interactions and Addiction. Front Pharmacol 2012; 3:84. [PMID: 22586398 PMCID: PMC3345582 DOI: 10.3389/fphar.2012.00084] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2011] [Accepted: 04/16/2012] [Indexed: 12/22/2022] Open
Abstract
The idea of “receptor mosaics” is that proteins may form complex and dynamic networks with respect to time and composition. These have the potential to markedly expand the diversity and specificity of G protein-coupled receptors (GPCR) signaling, particularly in neural cells, where a few key receptors have been implicated in many neurological and psychiatric disorders, including addiction. Metabotropic glutamate type 5 receptors (mGlu5) can form complexes with other GPCRs, including adenosine A2A and dopamine D2 receptors. mGlu5-containing complexes have been reported in the striatum, a brain region critical for mediating the rewarding and incentive motivational properties of drugs of abuse. mGlu5-containing complexes and/or downstream interactions between divergent receptors may play roles in addiction–relevant behaviors. Interactions between mGlu5 receptors and other GPCRs can regulate the rewarding and conditioned effects of drugs as well as drug-seeking behaviors. mGlu5 complexes may influence striatal function, including GABAergic output of striatopallidal neurons and glutamatergic input from corticostriatal afferents. Given their discrete localization, mGlu5-[non-mGlu5] receptor interactions and/or mGlu5-containing complexes may minimize off-target effects and thus provide a novel avenue for drug discovery. The therapeutic targeting of receptor–receptor functional interactions and/or receptor mosaics in a tissue specific or temporal manner (for example, a sub-population of receptors in a “pathological state”) might reduce detrimental side effects that may otherwise impair vital brain functions.
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Affiliation(s)
- Robyn M Brown
- Addiction Neuroscience, Behavioural Neuroscience, Florey Neuroscience Institutes, University of Melbourne Parkville, VIC, Australia
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