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Kahvandi N, Ebrahimi Z, Sharifi M, Karimi SA, Shahidi S, Salehi I, Haddadi R, Sarihi A. S-3,4-DCPG, a potent orthosteric agonist for the mGlu8 receptor, facilitates extinction and inhibits the reinstatement of morphine-induced conditioned place preference in male rats. Pharmacol Biochem Behav 2024; 240:173772. [PMID: 38653345 DOI: 10.1016/j.pbb.2024.173772] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/10/2023] [Revised: 04/13/2024] [Accepted: 04/17/2024] [Indexed: 04/25/2024]
Abstract
The limbic system, particularly the NAc, shows a high concentration of metabotropic glutamate receptors (mGluRs). Recent evidence suggests the significant involvement of mGluRs in mental disorders, including substance abuse and addiction. The objective of this study was to examine the involvement of mGlu8 receptors in the NAc in the mechanisms underlying the extinction and reinstatement of conditioned place preference (CPP) induced by morphine. Male Wistar rats underwent surgical implantation of bilateral cannulas in the NAc and were assessed in a CPP protocol. In study 1 at the same time as the extinction phase, the rats were given varying doses of S-3,4-DCPG (0.03, 0.3, and 3 μg/0.5 μl). In study 2, rats that had undergone CPP extinction were given S-3,4-DCPG (0.03, 0.3, and 3 μg/0.5 μl) five minutes prior to receiving a subthreshold dose of morphine (1 mg/kg) in order to reactivate the previously extinguished morphine response. The findings demonstrated that administering S-3,4-DCPG directly into the accumbens nucleus resulted in a decrease in the duration of the CPP extinction phase. Moreover, dose-dependent administration of S-3,4-DCPG into the NAc inhibited CPP reinstatement. The observations imply that microinjection of S-3,4-DCPG as a potent orthosteric agonist with high selectivity for the mGlu8 receptor into the NAc promotes the process of extinction while concurrently exerting inhibitory effects on the reinstatement of morphine-induced CPP. This effect may be associated with the modulation of glutamate engagement within the NAc and the plasticity of reward pathways at the synaptic level.
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Affiliation(s)
- Nazanin Kahvandi
- Neurophysiology Research Center, Hamadan University of Medical Sciences, Hamadan, Iran; Department of Physiology, Faculty of Medicine, Hamadan University of Medical Sciences, Hamadan, Iran
| | - Zahra Ebrahimi
- Neurophysiology Research Center, Hamadan University of Medical Sciences, Hamadan, Iran; Department of Physiology, Faculty of Medicine, Hamadan University of Medical Sciences, Hamadan, Iran
| | - Maryam Sharifi
- Neurophysiology Research Center, Hamadan University of Medical Sciences, Hamadan, Iran
| | - Seyed Asaad Karimi
- Neurophysiology Research Center, Hamadan University of Medical Sciences, Hamadan, Iran; Department of Neuroscience, School of Sciences and Advanced Technology in Medicine, Hamadan University of Medical Sciences, Hamadan, Iran
| | - Siamak Shahidi
- Neurophysiology Research Center, Hamadan University of Medical Sciences, Hamadan, Iran; Department of Neuroscience, School of Sciences and Advanced Technology in Medicine, Hamadan University of Medical Sciences, Hamadan, Iran
| | - Iraj Salehi
- Neurophysiology Research Center, Hamadan University of Medical Sciences, Hamadan, Iran; Department of Neuroscience, School of Sciences and Advanced Technology in Medicine, Hamadan University of Medical Sciences, Hamadan, Iran
| | - Rasool Haddadi
- Department of Pharmacology and Toxicology, School of Pharmacy, Hamadan University of Medical Sciences, Hamadan, Iran
| | - Abdolrahman Sarihi
- Neurophysiology Research Center, Hamadan University of Medical Sciences, Hamadan, Iran; Department of Neuroscience, School of Sciences and Advanced Technology in Medicine, Hamadan University of Medical Sciences, Hamadan, Iran.
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Alkhlaif Y, El-Halawany M, Toma W, Park A, Hamouda AK, Damaj MI. L-theanine attenuates nicotine reward and withdrawal signs in mice. Neurosci Lett 2023; 807:137279. [PMID: 37105354 PMCID: PMC10204724 DOI: 10.1016/j.neulet.2023.137279] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2023] [Revised: 04/22/2023] [Accepted: 04/24/2023] [Indexed: 04/29/2023]
Abstract
BACKGROUND L-theanine, 2-amino-4-(ethylcarbamoyl) butyric acid, an amino acid detected in green tea leaves, is used as a dietary supplement to attenuate stress and enhance mood and cognition. Furthermore, L-theanine induces anxiolytic effects in humans. Recently, L-theanine was reported to reduce morphine physical dependence in primates, suggesting the potential usefulness of L-theanine for drug dependence intervention. OBJECTIVE The aim of this study is to determine whether L-theanine attenuates nicotine-withdrawal (somatic and affective signs) and nicotine reward in mice. We also investigated the effects of L-theanine on nicotinic receptors binding and function. METHODS ICR male mice rendered dependent to nicotine through implanted subcutaneous osmotic minipumps for 14 days undertook precipitated nicotine withdrawal by mecamylamine on day 15. Anxiety-like behaviors using LDB, somatic signs observation and hot plate latency were assessed consecutively after treatment with L-theanine. Furthermore, we examined the effect of L-theanine on acute nicotine responses and nicotine conditioned reward in mice and on expressed nicotinic receptors in oocytes. KEY FINDINGS L-theanine reduced in a dose-dependent manner anxiety-like behavior, hyperalgesia and somatic signs during nicotine withdrawal. Also, L-theanine decreased the nicotine CPP, but it did not affect the acute responses of nicotine. Finally, L-theanine did not alter the binding or the function of expressed α4β2 and α7 nAChRs. CONCLUSION Our results support the potential of L-theanine as a promising candidate for treating nicotine dependence.
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Affiliation(s)
- Yasmin Alkhlaif
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, VA, United States
| | - Medhat El-Halawany
- Department of Pharmaceutical Sciences and Health Outcomes, College of Pharmacy, The University of Texas at Tyler, Tyler, TX, United States
| | - Wisam Toma
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, VA, United States
| | - Abigail Park
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, VA, United States
| | - Ayman K Hamouda
- Department of Pharmaceutical Sciences and Health Outcomes, College of Pharmacy, The University of Texas at Tyler, Tyler, TX, United States
| | - M Imad Damaj
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, VA, United States.
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Holter KM, Pierce BE, Gould RW. Metabotropic glutamate receptor function and regulation of sleep-wake cycles. INTERNATIONAL REVIEW OF NEUROBIOLOGY 2023; 168:93-175. [PMID: 36868636 DOI: 10.1016/bs.irn.2022.11.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Metabotropic glutamate (mGlu) receptors are the most abundant family of G-protein coupled receptors and are widely expressed throughout the central nervous system (CNS). Alterations in glutamate homeostasis, including dysregulations in mGlu receptor function, have been indicated as key contributors to multiple CNS disorders. Fluctuations in mGlu receptor expression and function also occur across diurnal sleep-wake cycles. Sleep disturbances including insomnia are frequently comorbid with neuropsychiatric, neurodevelopmental, and neurodegenerative conditions. These often precede behavioral symptoms and/or correlate with symptom severity and relapse. Chronic sleep disturbances may also be a consequence of primary symptom progression and can exacerbate neurodegeneration in disorders including Alzheimer's disease (AD). Thus, there is a bidirectional relationship between sleep disturbances and CNS disorders; disrupted sleep may serve as both a cause and a consequence of the disorder. Importantly, comorbid sleep disturbances are rarely a direct target of primary pharmacological treatments for neuropsychiatric disorders even though improving sleep can positively impact other symptom clusters. This chapter details known roles of mGlu receptor subtypes in both sleep-wake regulation and CNS disorders focusing on schizophrenia, major depressive disorder, post-traumatic stress disorder, AD, and substance use disorder (cocaine and opioid). In this chapter, preclinical electrophysiological, genetic, and pharmacological studies are described, and, when possible, human genetic, imaging, and post-mortem studies are also discussed. In addition to reviewing the important relationships between sleep, mGlu receptors, and CNS disorders, this chapter highlights the development of selective mGlu receptor ligands that hold promise for improving both primary symptoms and sleep disturbances.
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Affiliation(s)
- Kimberly M Holter
- Department of Physiology and Pharmacology, Wake Forest University School of Medicine, Winston-Salem, NC, United States
| | - Bethany E Pierce
- Department of Physiology and Pharmacology, Wake Forest University School of Medicine, Winston-Salem, NC, United States
| | - Robert W Gould
- Department of Physiology and Pharmacology, Wake Forest University School of Medicine, Winston-Salem, NC, United States.
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Seo SY, Yang JH, Kim S, Sohn S, Oh JH, Mao L, Wang JQ, Choe ES. Interaction of JNK and mGluR5 in the regulation of psychomotor behaviours after repeated cocaine administration. Addict Biol 2022; 27:e13127. [PMID: 35229936 DOI: 10.1111/adb.13127] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2021] [Revised: 12/01/2021] [Accepted: 12/03/2021] [Indexed: 11/30/2022]
Abstract
Activation of protein kinases after cocaine administration controls psychomotor behaviours by interacting with metabotropic receptors in the brain. This study identified how c-Jun N-terminal kinase (JNK) interacts with metabotropic glutamate receptor 5 (mGluR5) in vitro and in the caudate and putamen (CPu). The potential role of this interaction in the regulation of psychomotor behaviour was also evaluated after administration of cocaine. Active JNK phosphorylates a threonine residue at position 1055 in the carboxyl terminus (CT) of mGluR5 in vitro. The binding of active JNK to the D-motif within CT2 is necessary for that phosphorylation. Interaction of phosphorylated JNK and mGluR5 occurs in the CPu. Unilateral interference of the interaction decreases the repeated cocaine-induced increases in locomotor activity and conditioned place preference. These findings suggest that activation of JNK has the capability to interact with mGluR5 in the CPu. Phosphorylation of mGluR5 following the JNK-mGluR5 interaction may be responsible for the potentiation of behavioural sensitisation and cocaine-wanting behaviour in response to cocaine administration.
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Affiliation(s)
- Su Yeon Seo
- Department of Biological Sciences Pusan National University Busan South Korea
| | - Ju Hwan Yang
- Department of Biological Sciences Pusan National University Busan South Korea
| | - Sunghyun Kim
- Department of Biological Sciences Pusan National University Busan South Korea
| | - Sumin Sohn
- Department of Biological Sciences Pusan National University Busan South Korea
| | - Jeong Hwan Oh
- Department of Biological Sciences Pusan National University Busan South Korea
| | - Li‐Min Mao
- Department of Anesthesiology and Basic Medical Science University of Missouri–Kansas City Kansas City Missouri USA
| | - John Q. Wang
- Department of Anesthesiology and Basic Medical Science University of Missouri–Kansas City Kansas City Missouri USA
| | - Eun Sang Choe
- Department of Biological Sciences Pusan National University Busan South Korea
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Chang HA, Dai W, Hu SSJ. Sex differences in cocaine-associated memory: The interplay between CB 1, mGluR5, and estradiol. Psychoneuroendocrinology 2021; 133:105366. [PMID: 34419761 DOI: 10.1016/j.psyneuen.2021.105366] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/04/2020] [Revised: 07/16/2021] [Accepted: 07/22/2021] [Indexed: 10/20/2022]
Abstract
We know surprisingly little about the sex differences in the neurobiology of cocaine addiction, except females are more susceptible to the rewarding effects of cocaine than their male counterparts. Only a handful of recent studies have examined the neurobiology of cocaine-induced conditioned place preference (CPP) memory among female rodents. We contribute to this emerging line of research by documenting sex differences in cocaine-associated memory and illustrating the underlying signaling pathways in five experiments. Rimonabant (Rim), a cannabinoid CB1 antagonist and inverse agonist, exerted a facilitating effect for low-dose cocaine and an impairing effect for high-dose cocaine CPP memory in male mice, as in our previous study, but not in female mice. Nor did we observe the effect exist among CB1 knockout male mice, which indicated that the CB1 receptors played a mediating role. We also found that the metabotropic glutamate receptor 5 (mGluR5) was located in the same signaling pathway as CB1 in male mice. To clarify the mechanisms behind the sex differences, we used ovariectomized (OVX) female mice with estradiol benzoate (EB) replacement. In the OVX female mice, we showed that Rim-alone and EB-alone, but not Rim-and-EB-combined, facilitated the low-dose cocaine CPP memory. Moreover, 4-hydroxytamoxifen (4-OHT), an estrogen receptor (ER) antagonist, blocked Rim's and EB's facilitating effect. Finally, 2-methyl-6-(phenylethynyl)pyridine (MPEP), an mGluR5 antagonist, partially blocked EB's facilitating effect. In sum, we identified sex-specific effects of Rim on cocaine-induced CPP memory and the respective signaling pathways: mGluR5-CB1 for male mice and ER-mGluR5-CB1 for female mice. These findings may have merits for the development of sex-specific treatment for cocaine addiction.
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Affiliation(s)
- Heng-Ai Chang
- Department of Psychology, National Cheng Kung University, Tainan 70101, Taiwan; Institute of Basic Medical Sciences, National Cheng Kung University, Tainan 70101, Taiwan
| | - Wen Dai
- Department of Psychology, National Cheng Kung University, Tainan 70101, Taiwan
| | - Sherry Shu-Jung Hu
- Department of Psychology, National Cheng Kung University, Tainan 70101, Taiwan.
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Holter KM, Lekander AD, LaValley CM, Bedingham EG, Pierce BE, Sands LP, Lindsley CW, Jones CK, Gould RW. Partial mGlu 5 Negative Allosteric Modulator M-5MPEP Demonstrates Antidepressant-Like Effects on Sleep Without Affecting Cognition or Quantitative EEG. Front Neurosci 2021; 15:700822. [PMID: 34276300 PMCID: PMC8283128 DOI: 10.3389/fnins.2021.700822] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2021] [Accepted: 06/03/2021] [Indexed: 01/28/2023] Open
Abstract
Selective negative allosteric modulators (NAMs) targeting the metabotropic glutamate receptor subtype 5 (mGlu5) demonstrate anxiolytic-like and antidepressant-like effects yet concern regarding adverse effect liability remains. Functional coupling of mGlu5 with ionotropic N-methyl-D-aspartate receptors (NMDARs) represents a potential mechanism through which full inhibition leads to adverse effects, as NMDAR inhibition can induce cognitive impairments and psychotomimetic-like effects. Recent development of "partial" mGlu5 NAMs, characterized by submaximal but saturable levels of blockade, may represent a novel development approach to broaden the therapeutic index of mGlu5 NAMs. This study compared the partial mGlu5 NAM, M-5MPEP, with the full mGlu5 NAM, VU0424238 on sleep, cognition, and brain function alone and in combination with a subthreshold dose of the NMDAR antagonist, MK-801, using a paired-associates learning (PAL) cognition task and electroencephalography (EEG) in rats. M-5MPEP and VU0424238 decreased rapid eye movement (REM) sleep and increased REM sleep latency, both putative biomarkers of antidepressant-like activity. Neither compound alone affected accuracy, but 30 mg/kg VU0424238 combined with MK-801 decreased accuracy on the PAL task. Using quantitative EEG, VU0424238, but not M-5MPEP, prolonged arousal-related elevations in high gamma power, and, in combination, VU0424238 potentiated effects of MK-801 on high gamma power. Together, these studies further support a functional interaction between mGlu5 and NMDARs that may correspond with cognitive impairments. Present data support further development of partial mGlu5 NAMs given their potentially broader therapeutic index than full mGlu5 NAMs and use of EEG as a translational biomarker to titrate doses aligning with therapeutic versus adverse effects.
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Affiliation(s)
- Kimberly M. Holter
- Department of Physiology and Pharmacology, Wake Forest School of Medicine, Winston-Salem, NC, United States
| | - Alex D. Lekander
- Department of Physiology and Pharmacology, Wake Forest School of Medicine, Winston-Salem, NC, United States
| | - Christina M. LaValley
- Department of Physiology and Pharmacology, Wake Forest School of Medicine, Winston-Salem, NC, United States
| | | | - Bethany E. Pierce
- Department of Physiology and Pharmacology, Wake Forest School of Medicine, Winston-Salem, NC, United States
| | - L. Paul Sands
- Department of Physiology and Pharmacology, Wake Forest School of Medicine, Winston-Salem, NC, United States
| | - Craig W. Lindsley
- Department of Pharmacology, Vanderbilt University Medical Center, Nashville, TN, United States
- Warren Center for Neuroscience Drug Discovery, Vanderbilt University, Nashville, TN, United States
- Department of Chemistry, Vanderbilt University Medical Center, Nashville, TN, United States
| | - Carrie K. Jones
- Department of Pharmacology, Vanderbilt University Medical Center, Nashville, TN, United States
- Warren Center for Neuroscience Drug Discovery, Vanderbilt University, Nashville, TN, United States
| | - Robert W. Gould
- Department of Physiology and Pharmacology, Wake Forest School of Medicine, Winston-Salem, NC, United States
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Angarita GA, Hadizadeh H, Cerdena I, Potenza MN. Can pharmacotherapy improve treatment outcomes in people with co-occurring major depressive and cocaine use disorders? Expert Opin Pharmacother 2021; 22:1669-1683. [PMID: 34042556 DOI: 10.1080/14656566.2021.1931684] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
Introduction: Major depressive disorder (MDD) and cocaine use disorder (CUD) are prevalent and frequently co-occur. When co-occurring, the presence of one disorder typically negatively impacts the prognosis for the other. Given the clinical relevance, we sought to examine pharmacotherapies for co-occurring CUD and MDD. While multiple treatment options have been examined in the treatment of each condition individually, studies exploring pharmacological options for their comorbidity are fewer and not conclusive.Areas Covered: For this review, the authors searched the literature in PubMed using clinical query options for therapies and keywords relating to each condition. Then, they described potentially promising pharmacologic therapeutic options based on shared mechanisms between the two conditions and/or results from individual clinical trials conducted to date.Expert opinion: Medications like stimulants, dopamine (D3) receptors partial agonists or antagonists, antagonists of kappa opioid receptors, topiramate, and ketamine could be promising as there is significant overlap relating to reward deficiency models, antireward pathways, and altered glutamatergic systems. However, the available clinical literature on any one of these types of agents is mixed. Additionally, for some agents there is possible concern related to abuse potential (e.g. ketamine and stimulants).
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Affiliation(s)
- Gustavo A Angarita
- Department of Psychiatry, Yale University School of Medicine, New Haven, CT, USA.,Clinical Neuroscience Research Unit, Connecticut Mental Health Center, New Haven, CT, USA
| | - Hasti Hadizadeh
- Department of Psychiatry, Yale University School of Medicine, New Haven, CT, USA.,Clinical Neuroscience Research Unit, Connecticut Mental Health Center, New Haven, CT, USA
| | - Ignacio Cerdena
- Department of Psychiatry, Yale University School of Medicine, New Haven, CT, USA.,Connecticut Mental Health Center, New Haven, CT, USA
| | - Marc N Potenza
- Department of Psychiatry, Yale University School of Medicine, New Haven, CT, USA.,Connecticut Mental Health Center, New Haven, CT, USA.,Child Study Center, Yale University School of Medicine, New Haven, CT, USA.,Department of Neuroscience, Yale University, New Haven, CT, USA.,Connecticut Council on Problem Gambling, Wethersfield, CT, USA
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8
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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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Heinsbroek JA, De Vries TJ, Peters J. Glutamatergic Systems and Memory Mechanisms Underlying Opioid Addiction. Cold Spring Harb Perspect Med 2021; 11:cshperspect.a039602. [PMID: 32341068 DOI: 10.1101/cshperspect.a039602] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Glutamate is the main excitatory neurotransmitter in the brain and is of critical importance for the synaptic and circuit mechanisms that underlie opioid addiction. Opioid memories formed over the course of repeated drug use and withdrawal can become powerful stimuli that trigger craving and relapse, and glutamatergic neurotransmission is essential for the formation and maintenance of these memories. In this review, we discuss the mechanisms by which glutamate, dopamine, and opioid signaling interact to mediate the primary rewarding effects of opioids, and cover the glutamatergic systems and circuits that mediate the expression, extinction, and reinstatement of opioid seeking over the course of opioid addiction.
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Affiliation(s)
- Jasper A Heinsbroek
- Department of Anesthesiology, University of Colorado School of Medicine, Aurora, Colorado 80045, USA
| | - Taco J De Vries
- Amsterdam Neuroscience, Department of Molecular and Cellular Neurobiology, Center for Neurogenomics and Cognitive Research, Faculty of Earth and Life Sciences, VU University, 1081HV Amsterdam, The Netherlands.,Amsterdam Neuroscience, Department of Anatomy and Neurosciences, VU University Medical Center, 1081HZ Amsterdam, The Netherlands
| | - Jamie Peters
- Department of Anesthesiology, University of Colorado School of Medicine, Aurora, Colorado 80045, USA
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Johnson KA, Lovinger DM. Allosteric modulation of metabotropic glutamate receptors in alcohol use disorder: Insights from preclinical investigations. ADVANCES IN PHARMACOLOGY (SAN DIEGO, CALIF.) 2020; 88:193-232. [PMID: 32416868 DOI: 10.1016/bs.apha.2020.02.002] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Metabotropic glutamate (mGlu) receptors are family C G protein-coupled receptors (GPCRs) that modulate neuronal excitability and synaptic transmission throughout the nervous system. Owing to recent advances in development of subtype-selective allosteric modulators of mGlu receptors, individual members of the mGlu receptor family have been proposed as targets for treating a variety of neurological and psychiatric disorders, including substance use disorders. In this chapter, we highlight preclinical evidence that allosteric modulators of mGlu receptors could be useful for reducing alcohol consumption and preventing relapse in alcohol use disorder (AUD). We begin with an overview of the preclinical models that are used to study mGlu receptor involvement in alcohol-related behaviors. Alcohol exposure causes adaptations in both expression and function of various mGlu receptor subtypes, and pharmacotherapies aimed at reversing these adaptations have the potential to reduce alcohol consumption and seeking. Positive allosteric modulators (PAMs) of mGlu2 and negative allosteric modulators of mGlu5 show particular promise for reducing alcohol intake and/or preventing relapse. Finally, this chapter discusses important considerations for translating preclinical findings toward the development of clinically useful drugs, including the potential for PAMs to avoid tolerance issues that are frequently observed with repeated administration of GPCR agonists.
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Affiliation(s)
- Kari A Johnson
- Department of Pharmacology, Uniformed Services University of the Health Sciences, Bethesda, MD, United States.
| | - David M Lovinger
- Laboratory for Integrative Neuroscience, National Institute on Alcohol Abuse and Alcoholism, US National Institutes of Health, Rockville, MD, United States
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Wu CS, Jew CP, Sun H, Ballester Rosado CJ, Lu HC. mGlu5 in GABAergic neurons modulates spontaneous and psychostimulant-induced locomotor activity. Psychopharmacology (Berl) 2020; 237:345-361. [PMID: 31646346 PMCID: PMC7024012 DOI: 10.1007/s00213-019-05367-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/04/2019] [Accepted: 09/22/2019] [Indexed: 12/17/2022]
Abstract
RATIONALE A role of group I metabotropic glutamate receptor 5 (mGlu5) in regulating spontaneous locomotion and psychostimulant-induced hyperactivity has been proposed. OBJECTIVES This study aims to determine if mGlu5 in GABAergic neurons regulates spontaneous or psychostimulant-induced locomotion. METHODS We generated mice specifically lacking mGlu5 in forebrain GABAergic neuron by crossing DLX-Cre mice with mGlu5flox/flox mice to generate DLX-mGlu5 KO mice. The locomotion of adult mice was examined in the open-field assay (OFA) and home cage setting. The effects of the mGlu5 antagonist 6-methyl-2-(phenylethynyl)pyridine (MPEP), cocaine, and methylphenidate on acute motor behaviors in DLX-mGlu5 KO and littermate control mice were assessed in OFA. Striatal synaptic plasticity of these mice was examined with field potential electrophysiological recordings. RESULTS Deleting mGlu5 from forebrain GABAergic neurons results in failure to induce long-term depression (LTD) in the dorsal striatum and absence of habituated locomotion in both novel and familiar settings. In a familiar environment (home cage), DLX-mGlu5 KO mice were hyperactive. In the OFA, DLX-mGlu5 KO mice exhibited initial hypo-activity, and then gradually increased their locomotion with time, resulting in no habituation response. DLX-mGlu5 KO mice exhibited almost no locomotor response to MPEP (40 mg/kg), while the same dose elicited hyperlocomotion in control mice. The DLX-mGlu5 KO mice also showed reduced hyperactivity response to cocaine, while they retained normal hyperactivity response to methylphenidate, albeit with delayed onset. CONCLUSION mGlu5 in forebrain GABAergic neurons is critical to trigger habituation upon the initiation of locomotion as well as to mediate MPEP-induced hyperlocomotion and modulate psychostimulant-induced hyperactivity.
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Affiliation(s)
- Chia-Shan Wu
- The Cain Foundation Laboratories, Baylor College of Medicine, Houston, 77030, TX, USA.
- Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, 77030, TX, USA.
- Department of Nutrition and Food Science, Texas A&M University, 123 Cater-Mattil, 2253 TAMU, College Station, TX, 77843, USA.
| | - Christopher P Jew
- The Cain Foundation Laboratories, Baylor College of Medicine, Houston, 77030, TX, USA
- Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, 77030, TX, USA
- Program in Developmental Biology, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Hao Sun
- The Cain Foundation Laboratories, Baylor College of Medicine, Houston, 77030, TX, USA
- Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, 77030, TX, USA
| | - Carlos J Ballester Rosado
- The Cain Foundation Laboratories, Baylor College of Medicine, Houston, 77030, TX, USA
- Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, 77030, TX, USA
- Program in Developmental Biology, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Hui-Chen Lu
- The Cain Foundation Laboratories, Baylor College of Medicine, Houston, 77030, TX, USA.
- Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, 77030, TX, USA.
- Program in Developmental Biology, Baylor College of Medicine, Houston, TX, 77030, USA.
- Linda and Jack Gill Center, Department of Psychological and Brain Sciences, Indiana University, 1101 E. 10th Street, Bloomington, IN, 47405, USA.
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Niedzielska-Andres E, Mizera J, Sadakierska-Chudy A, Pomierny-Chamioło L, Filip M. Changes in the glutamate biomarker expression in rats vulnerable or resistant to the rewarding effects of cocaine and their reversal by ceftriaxone. Behav Brain Res 2019; 370:111945. [DOI: 10.1016/j.bbr.2019.111945] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2019] [Revised: 05/11/2019] [Accepted: 05/13/2019] [Indexed: 02/06/2023]
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13
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Kasten CR, Holmgren EB, Wills TA. Metabotropic Glutamate Receptor Subtype 5 in Alcohol-Induced Negative Affect. Brain Sci 2019; 9:E183. [PMID: 31366097 PMCID: PMC6721373 DOI: 10.3390/brainsci9080183] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2019] [Revised: 07/26/2019] [Accepted: 07/28/2019] [Indexed: 02/07/2023] Open
Abstract
Allosteric modulators of metabotropic glutamate 5 receptors (mGlu5 receptors) have been identified as a promising treatment to independently alleviate both negative affective states and ethanol-seeking and intake. However, these conditions are often comorbid and might precipitate one another. Acute and protracted ethanol withdrawal can lead to negative affective states. In turn, these states are primary drivers of alcohol relapse, particularly among women. The current review synthesizes preclinical studies that have observed the role of mGlu5 receptor modulation in negative affective states following ethanol exposure. The primary behavioral assays discussed are ethanol-seeking and intake, development and extinction of ethanol-associated cues and contexts, behavioral despair, and anxiety-like activity. The work done to-date supports mGlu5 receptor modulation as a promising target for mediating negative affective states to reduce ethanol intake or prevent relapse. Limitations in interpreting these data include the lack of models that use alcohol-dependent animals, limited use of adolescent and female subjects, and a lack of comprehensive evaluations of negative affective-like behavior.
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Affiliation(s)
- Chelsea R Kasten
- LSU Health Sciences Center-New Orleans, Department of Cell Biology and Anatomy, Medical Education Building, 1901 Perdido Street, Room 6103, New Orleans, LA 70112, USA
| | - Eleanor B Holmgren
- LSU Health Sciences Center-New Orleans, Department of Cell Biology and Anatomy, Medical Education Building, 1901 Perdido Street, Room 6103, New Orleans, LA 70112, USA
| | - Tiffany A Wills
- LSU Health Sciences Center-New Orleans, Department of Cell Biology and Anatomy, Medical Education Building, 1901 Perdido Street, Room 6103, New Orleans, LA 70112, USA.
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14
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Areal LB, Hamilton A, Martins-Silva C, Pires RGW, Ferguson SSG. Neuronal scaffolding protein spinophilin is integral for cocaine-induced behavioral sensitization and ERK1/2 activation. Mol Brain 2019; 12:15. [PMID: 30803445 PMCID: PMC6388481 DOI: 10.1186/s13041-019-0434-7] [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: 11/18/2018] [Accepted: 02/04/2019] [Indexed: 01/23/2023] Open
Abstract
Spinophilin is a scaffolding protein enriched in dendritic spines with integral roles in the regulation of spine density and morphology, and the modulation of synaptic plasticity. The ability of spinophilin to alter synaptic strength appears to involve its scaffolding of key synaptic proteins, including the important structural element F-actin, AMPA/NMDA modulator protein phosphatase 1, and neuromodulatory G-protein coupled receptors, including dopamine receptor D2 and metabotropic glutamate receptor 5. Additionally, spinophilin is highly expressed in the striatum, a brain region that is fundamentally involved in reward-processing and locomotor activity which receives both glutamatergic and dopaminergic inputs. Therefore, we aimed to investigate the role of spinophilin in behavioral responses to cocaine, evaluating wild-type and spinophilin knockout mice followed by the examination of underlying molecular alterations. Although acute locomotor response was not affected, deletion of spinophilin blocked the development and expression of behavioral sensitization to cocaine while maintaining normal conditioned place preference. This behavioral alteration in spinophilin knockout mice was accompanied by attenuated c-Fos and ∆FosB expression following cocaine administration and blunted cocaine-induced phosphorylation of ERK1/2 in the striatum, with no change in other relevant signaling molecules. Therefore, we suggest spinophilin fulfills an essential role in cocaine-induced behavioral sensitization, likely via ERK1/2 phosphorylation and induction of c-Fos and ∆FosB in the striatum, a mechanism that may underlie specific processes in cocaine addiction.
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Affiliation(s)
- Lorena Bianchine Areal
- Department of Cellular and Molecular Medicine and University of Ottawa Brain and Mind Institute, University of Ottawa, 451 Smyth Road, Ottawa, ON, K1H 8M5, Canada.,Graduate Program in Neuroscience, Institute of Biological Sciences, Federal University of Minas Gerais, Belo Horizonte, MG, 31270-901, Brazil
| | - Alison Hamilton
- Department of Cellular and Molecular Medicine and University of Ottawa Brain and Mind Institute, University of Ottawa, 451 Smyth Road, Ottawa, ON, K1H 8M5, Canada
| | - Cristina Martins-Silva
- Department of Physiological Sciences, Health Sciences Center, Federal University of Espirito, Santo, Vitoria, ES, 29043-910, Brazil
| | - Rita Gomes Wanderley Pires
- Graduate Program in Neuroscience, Institute of Biological Sciences, Federal University of Minas Gerais, Belo Horizonte, MG, 31270-901, Brazil.,Department of Physiological Sciences, Health Sciences Center, Federal University of Espirito, Santo, Vitoria, ES, 29043-910, Brazil
| | - Stephen S G Ferguson
- Department of Cellular and Molecular Medicine and University of Ottawa Brain and Mind Institute, University of Ottawa, 451 Smyth Road, Ottawa, ON, K1H 8M5, Canada.
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15
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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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16
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Gross KS, Moore KM, Meisel RL, Mermelstein PG. mGluR5 Mediates Dihydrotestosterone-Induced Nucleus Accumbens Structural Plasticity, but Not Conditioned Reward. Front Neurosci 2018; 12:855. [PMID: 30515075 PMCID: PMC6255826 DOI: 10.3389/fnins.2018.00855] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2018] [Accepted: 11/01/2018] [Indexed: 12/12/2022] Open
Abstract
Gonadal hormones play a vital role in driving motivated behavior. They not only modulate responses to naturally rewarding stimuli, but also influence responses to drugs of abuse. A commonality between gonadal hormones and drugs of abuse is that they both impact the neurocircuitry of reward, including the regulation of structural plasticity in the nucleus accumbens (NAc). Previous hormonal studies have focused on the mechanisms and behavioral correlates of estradiol-induced dendritic spine changes in the female NAc. Here we sought to determine the effects of androgens on medium spiny neuron (MSN) spine plasticity in the male NAc. Following treatment with the androgen receptor agonist dihydrotestosterone (DHT), MSNs in castrated male rats exhibited a significant decrease in dendritic spine density. This effect was isolated to the shell subregion of the NAc. The effect of DHT was dependent on mGluR5 activity, and local mGluR5 activation and subsequent endocannabinoid signaling produce an analogous NAc shell spine decrease. Somewhat surprisingly, DHT-induced conditioned place preference remained intact following systemic inhibition of mGluR5. These findings indicate that androgens can utilize mGluR signaling, similar to estrogens, to mediate changes in NAc dendritic structure. In addition, there are notable differences in the direction of spine changes, and site specificity of estrogen and androgen action, suggesting sex differences in the hormonal regulation of motivated behaviors.
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Affiliation(s)
- Kellie S Gross
- Graduate Program in Neuroscience, University of Minnesota, Minneapolis, MN, United States.,Department of Neuroscience, University of Minnesota, Minneapolis, MN, United States
| | - Kelsey M Moore
- Graduate Program in Neuroscience, University of Minnesota, Minneapolis, MN, United States.,Department of Neuroscience, University of Minnesota, Minneapolis, MN, United States
| | - Robert L Meisel
- Graduate Program in Neuroscience, University of Minnesota, Minneapolis, MN, United States.,Department of Neuroscience, University of Minnesota, Minneapolis, MN, United States
| | - Paul G Mermelstein
- Graduate Program in Neuroscience, University of Minnesota, Minneapolis, MN, United States.,Department of Neuroscience, University of Minnesota, Minneapolis, MN, United States
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17
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Joffe ME, Centanni SW, Jaramillo AA, Winder DG, Conn PJ. Metabotropic Glutamate Receptors in Alcohol Use Disorder: Physiology, Plasticity, and Promising Pharmacotherapies. ACS Chem Neurosci 2018; 9:2188-2204. [PMID: 29792024 PMCID: PMC6192262 DOI: 10.1021/acschemneuro.8b00200] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Developing efficacious treatments for alcohol use disorder (AUD) has proven difficult. The insidious nature of the disease necessitates a deep understanding of its underlying biology as well as innovative approaches to ameliorate ethanol-related pathophysiology. Excessive ethanol seeking and relapse are generated by long-term changes to membrane properties, synaptic physiology, and plasticity throughout the limbic system and associated brain structures. Each of these factors can be modulated by metabotropic glutamate (mGlu) receptors, a diverse set of G protein-coupled receptors highly expressed throughout the central nervous system. Here, we discuss how different components of the mGlu receptor family modulate neurotransmission in the limbic system and other brain regions involved in AUD etiology. We then describe how these processes are dysregulated following ethanol exposure and speculate about how mGlu receptor modulation might restore such pathophysiological changes. To that end, we detail the current understanding of the behavioral pharmacology of mGlu receptor-directed drug-like molecules in animal models of AUD. Together, this review highlights the prominent position of the mGlu receptor system in the pathophysiology of AUD and provides encouragement that several classes of mGlu receptor modulators may be translated as viable treatment options.
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Affiliation(s)
- Max E. Joffe
- Department of Pharmacology, Vanderbilt University, Nashville, Tennessee 37232-0697, United States
- Vanderbilt Center for Neuroscience Drug Discovery, Vanderbilt University, Nashville, Tennessee 37232-0697, United States
- Vanderbilt Center for Addiction Research, Vanderbilt University, Nashville, Tennessee 37232-0697, United States
| | - Samuel W. Centanni
- Vanderbilt Center for Addiction Research, Vanderbilt University, Nashville, Tennessee 37232-0697, United States
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, Tennessee 37212, United States
| | - Anel A. Jaramillo
- Vanderbilt Center for Addiction Research, Vanderbilt University, Nashville, Tennessee 37232-0697, United States
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, Tennessee 37212, United States
| | - Danny G. Winder
- Department of Pharmacology, Vanderbilt University, Nashville, Tennessee 37232-0697, United States
- Vanderbilt Center for Addiction Research, Vanderbilt University, Nashville, Tennessee 37232-0697, United States
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, Tennessee 37212, United States
| | - P. Jeffrey Conn
- Department of Pharmacology, Vanderbilt University, Nashville, Tennessee 37232-0697, United States
- Vanderbilt Center for Neuroscience Drug Discovery, Vanderbilt University, Nashville, Tennessee 37232-0697, United States
- Vanderbilt Center for Addiction Research, Vanderbilt University, Nashville, Tennessee 37232-0697, United States
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18
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Steffensen SC, Shin SI, Nelson AC, Pistorius SS, Williams SB, Woodward TJ, Park HJ, Friend L, Gao M, Gao F, Taylor DH, Foster Olive M, Edwards JG, Sudweeks SN, Buhlman LM, Michael McIntosh J, Wu J. α6 subunit-containing nicotinic receptors mediate low-dose ethanol effects on ventral tegmental area neurons and ethanol reward. Addict Biol 2018; 23:1079-1093. [PMID: 28901722 DOI: 10.1111/adb.12559] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2017] [Revised: 08/17/2017] [Accepted: 08/18/2017] [Indexed: 01/02/2023]
Abstract
Dopamine (DA) neuron excitability is regulated by inhibitory GABAergic synaptic transmission and modulated by nicotinic acetylcholine receptors (nAChRs). The aim of this study was to evaluate the role of α6 subunit-containing nAChRs (α6*-nAChRs) in acute ethanol effects on ventral tegmental area (VTA) GABA and DA neurons. α6*-nAChRs were visualized on GABA terminals on VTA GABA neurons, and α6*-nAChR transcripts were expressed in most DA neurons, but only a minority of VTA GABA neurons from GAD67 GFP mice. Low concentrations of ethanol (1-10 mM) enhanced GABAA receptor (GABAA R)-mediated spontaneous and evoked inhibition with blockade by selective α6*-nAChR antagonist α-conotoxins (α-Ctxs) and lowered sensitivity in α6 knock-out (KO) mice. Ethanol suppression of VTA GABA neuron firing rate in wild-type mice in vivo was significantly reduced in α6 KO mice. Ethanol (5-100 mM) had no effect on optically evoked GABAA R-mediated inhibition of DA neurons, and ethanol enhancement of VTA DA neuron firing rate at high concentrations was not affected by α-Ctxs. Ethanol conditioned place preference was reduced in α6 KO mice compared with wild-type controls. Taken together, these studies indicate that relatively low concentrations of ethanol act through α6*-nAChRs on GABA terminals to enhance GABA release onto VTA GABA neurons, in turn to reduce GABA neuron firing, which may lead to VTA DA neuron disinhibition, suggesting a possible mechanism of action of alcohol and nicotine co-abuse.
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Affiliation(s)
- Scott C. Steffensen
- Department of Psychology and Neuroscience; Brigham Young University; Provo UT USA
| | - Samuel I. Shin
- Department of Psychology and Neuroscience; Brigham Young University; Provo UT USA
| | - Ashley C. Nelson
- Department of Psychology and Neuroscience; Brigham Young University; Provo UT USA
| | | | | | - Taylor J. Woodward
- Department of Psychology and Neuroscience; Brigham Young University; Provo UT USA
| | - Hyun Jung Park
- Department of Psychology and Neuroscience; Brigham Young University; Provo UT USA
| | - Lindsey Friend
- Department of Psychology and Neuroscience; Brigham Young University; Provo UT USA
| | - Ming Gao
- Department of Neurobiology, Barrow Neurological Institute; St. Joseph's Hospital and Medical Center; Phoenix AZ USA
| | - Fenfei Gao
- Department of Neurobiology, Barrow Neurological Institute; St. Joseph's Hospital and Medical Center; Phoenix AZ USA
| | | | - M. Foster Olive
- School of Psychology; Arizona State University; Tempe AZ USA
| | - Jeffrey G. Edwards
- Department of Psychology and Neuroscience; Brigham Young University; Provo UT USA
| | - Sterling N. Sudweeks
- Department of Psychology and Neuroscience; Brigham Young University; Provo UT USA
| | - Lori M. Buhlman
- Biomedical Sciences Program; Midwestern University; Glendale AZ USA
| | - J. Michael McIntosh
- Departments of Psychiatry and Biology; University of Utah; Salt Lake City UT USA
| | - Jie Wu
- Department of Neurobiology, Barrow Neurological Institute; St. Joseph's Hospital and Medical Center; Phoenix AZ USA
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19
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Rorabaugh BR, Rose MJ, Stoops TS, Stevens AA, Seeley SL, D'Souza MS. Regulators of G-protein signaling 2 and 4 differentially regulate cocaine-induced rewarding effects. Physiol Behav 2018; 195:9-19. [PMID: 30036561 DOI: 10.1016/j.physbeh.2018.07.016] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2018] [Revised: 07/16/2018] [Accepted: 07/19/2018] [Indexed: 01/11/2023]
Abstract
There is a need to identify new therapeutic targets for the treatment of cocaine addiction due to the rise in cocaine abuse and deaths due to cocaine overdose. Regulator of G protein signaling (RGS) proteins such as RGS2 and RGS4 are widely distributed in brain regions that play a role in drug reward. Importantly, RGS2 and RGS4 negatively regulate G-protein coupled receptor signaling pathways of monoaminergic neurotransmitters that play a role in the rewarding effects of cocaine by enhancing the rate of hydrolysis of Gα-bound guanine nucleotide triphosphate. Thus, the objective of this study was to investigate the effects of cocaine on conditioned place preference (CPP) and locomotor activity in mice that lacked either RGS2 or RGS4 (i.e. knockout (KO) mice) and their wildtype (WT) littermates. Moreover recent studies have reported influence of sex on RGS functioning and hence studies were conducted in both male and female mice. Cocaine-induced CPP was attenuated in male, but not female RGS4 KO mice compared to respective RGS4 WT mice. Cocaine-induced CPP was not influenced by deletion of RGS2 in either male or female mice. Similarly, cocaine-induced locomotor activity was not influenced by deletion of either RGS2 or RGS4 irrespective of sex. Together, the data indicate that the rewarding effects of cocaine were attenuated in the absence of RGS4 expression, but not in the absence of RGS2 expression in a sex-dependent manner. Importantly, these data suggest that RGS4 can serve as a potential target for medications that can be used to treat cocaine addiction.
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Affiliation(s)
- Boyd R Rorabaugh
- Department of Pharmaceutical and Biomedical Sciences, The Raabe College of Pharmacy, Ohio Northern University, 525 S Main Street, Ada, OH 45810, United States
| | - Madison J Rose
- Department of Pharmaceutical and Biomedical Sciences, The Raabe College of Pharmacy, Ohio Northern University, 525 S Main Street, Ada, OH 45810, United States
| | - Thorne S Stoops
- Department of Pharmaceutical and Biomedical Sciences, The Raabe College of Pharmacy, Ohio Northern University, 525 S Main Street, Ada, OH 45810, United States
| | - Allison A Stevens
- Department of Pharmaceutical and Biomedical Sciences, The Raabe College of Pharmacy, Ohio Northern University, 525 S Main Street, Ada, OH 45810, United States
| | - Sarah L Seeley
- Department of Pharmaceutical and Biomedical Sciences, The Raabe College of Pharmacy, Ohio Northern University, 525 S Main Street, Ada, OH 45810, United States
| | - Manoranjan S D'Souza
- Department of Pharmaceutical and Biomedical Sciences, The Raabe College of Pharmacy, Ohio Northern University, 525 S Main Street, Ada, OH 45810, United States.
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20
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Loiodice S, McGhan P, Gryshkova V, Fleurance R, Dardou D, Hafidi A, Nogueira da Costa A, Durif F. Striatal changes underlie MPEP-mediated suppression of the acquisition and expression of pramipexole-induced place preference in an alpha-synuclein rat model of Parkinson's disease. J Psychopharmacol 2017. [PMID: 28631520 DOI: 10.1177/0269881117714051] [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] [Indexed: 12/21/2022]
Abstract
Impulsive-compulsive disorders in Parkinson's disease patients have been described as behavioural or substance addictions including pathological gambling or compulsive medication use of dopamine replacement therapy. A substantial gap remains in the understanding of these disorders. We previously demonstrated that the rewarding effect of the D2/D3 agonist pramipexole was enhanced after repeated exposure to L-dopa and alpha-synuclein mediated dopaminergic nigral loss with specific transcriptional signatures suggesting a key involvement of the glutamatergic pathway. Here, we further investigate the therapeutic potential of metabotropic glutamate receptor 5 antagonism in Parkinson's disease/dopamine replacement therapy related bias of reward-mediated associative learning. We identified protein changes underlying the striatal remodelling associated with the pramipexole-induced conditioned place preference. Acquisition and expression of the pramipexole-induced conditioned place preference were abolished by the metabotropic glutamate receptor 5 antagonist 2-methyl-6-phenylethynyl (pyridine) (conditioned place preference scores obtained with pramipexole conditioning were reduced by 12.5% and 125.8% when 2-methyl-6-phenylethynyl (pyridine) was co-administrated with pramipexole or after the pramipexole conditioning, respectively). Up-regulation of the metabotropic glutamate receptor 5 was found in the dorsomedial-striatum and nucleus accumbens core. Activation of these two brain sub-regions was also highlighted through FosB immunohistochemistry. Convergent molecular and pharmacological data further suggests metabotropic glutamate receptor 5 as a promising therapeutic target for the management of Parkinson's disease/dopamine replacement therapy related reward bias.
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Affiliation(s)
- Simon Loiodice
- 1 EA7280 Neuropsychopharmacology of sub-cortical dopaminergic pathways, Université d'Auvergne, Clermont-Ferrand, France.,2 Department of Non-Clinical Development, UCB Biopharma SPRL, Braine-l'Alleud, Belgium
| | - Portia McGhan
- 2 Department of Non-Clinical Development, UCB Biopharma SPRL, Braine-l'Alleud, Belgium
| | - Vitalina Gryshkova
- 2 Department of Non-Clinical Development, UCB Biopharma SPRL, Braine-l'Alleud, Belgium
| | - Renaud Fleurance
- 2 Department of Non-Clinical Development, UCB Biopharma SPRL, Braine-l'Alleud, Belgium
| | - David Dardou
- 1 EA7280 Neuropsychopharmacology of sub-cortical dopaminergic pathways, Université d'Auvergne, Clermont-Ferrand, France
| | - Aziz Hafidi
- 1 EA7280 Neuropsychopharmacology of sub-cortical dopaminergic pathways, Université d'Auvergne, Clermont-Ferrand, France
| | | | - Franck Durif
- 1 EA7280 Neuropsychopharmacology of sub-cortical dopaminergic pathways, Université d'Auvergne, Clermont-Ferrand, France.,3 Neurology Department, CHU Clermont-Ferrand, Clermont-Ferrand, France
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21
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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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22
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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: 372] [Impact Index Per Article: 53.1] [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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Goodwani S, Saternos H, Alasmari F, Sari Y. Metabotropic and ionotropic glutamate receptors as potential targets for the treatment of alcohol use disorder. Neurosci Biobehav Rev 2017; 77:14-31. [PMID: 28242339 DOI: 10.1016/j.neubiorev.2017.02.024] [Citation(s) in RCA: 55] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2016] [Revised: 02/13/2017] [Accepted: 02/22/2017] [Indexed: 12/16/2022]
Abstract
Emerging evidence indicates that dysfunctional glutamate neurotransmission is critical in the initiation and development of alcohol and drug dependence. Alcohol consumption induced downregulation of glutamate transporter 1 (GLT-1) as reported in previous studies from our laboratory. Glutamate is the major excitatory neurotransmitter in the brain, which acts via interactions with several glutamate receptors. Alcohol consumption interferes with the glutamatergic signal transmission by altering the functions of these receptors. Among the glutamate receptors involved in alcohol-drinking behavior are the metabotropic receptors such as mGluR1/5, mGluR2/3, and mGluR7, as well as the ionotropic receptors, NMDA and AMPA. Preclinical studies using agonists and antagonists implicate these glutamatergic receptors in the development of alcohol use disorder (AUD). Therefore, the purpose of this review is to discuss the neurocircuitry involving glutamate transmission in animals exposed to alcohol and further outline the role of metabotropic and ionotropic receptors in the regulation of alcohol-drinking behavior. This review provides ample information about the potential therapeutic role of glutamatergic receptors for the treatment of AUD.
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Affiliation(s)
- Sunil Goodwani
- University of Toledo, College of Pharmacy and Pharmaceutical Sciences, Department of Pharmacology and Experimental Therapeutics, Toledo, OH 43614, USA; The Neurodegeneration Consortium, Institute for Applied Cancer Science, The University of Texas MD Anderson Cancer Center, Houston, TX, 77054, USA
| | - Hannah Saternos
- University of Toledo, College of Pharmacy and Pharmaceutical Sciences, Department of Pharmacology and Experimental Therapeutics, Toledo, OH 43614, USA
| | - Fawaz Alasmari
- University of Toledo, College of Pharmacy and Pharmaceutical Sciences, Department of Pharmacology and Experimental Therapeutics, Toledo, OH 43614, USA
| | - Youssef Sari
- University of Toledo, College of Pharmacy and Pharmaceutical Sciences, Department of Pharmacology and Experimental Therapeutics, Toledo, OH 43614, USA.
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Emmitte KA. mGlu5negative allosteric modulators: a patent review (2013 - 2016). Expert Opin Ther Pat 2017; 27:691-706. [DOI: 10.1080/13543776.2017.1280466] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Affiliation(s)
- Kyle A. Emmitte
- Department of Pharmaceutical Sciences, UNT System College of Pharmacy, University of North Texas Health Science Center, Fort Worth, TX, USA
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25
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mGluR5 activation in the nucleus accumbens is not essential for sexual behavior or cross-sensitization of amphetamine responses by sexual experience. Neuropharmacology 2016; 107:122-130. [DOI: 10.1016/j.neuropharm.2016.03.002] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2015] [Revised: 02/11/2016] [Accepted: 03/01/2016] [Indexed: 12/23/2022]
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26
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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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Lee JY, Choe ES, Yang CH, Choi KH, Cheong JH, Jang CG, Seo JW, Yoon SS. The mGluR5 antagonist MPEP suppresses the expression and reinstatement, but not the acquisition, of the ethanol-conditioned place preference in mice. Pharmacol Biochem Behav 2016; 140:33-8. [DOI: 10.1016/j.pbb.2015.10.015] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/30/2015] [Revised: 10/05/2015] [Accepted: 10/23/2015] [Indexed: 01/29/2023]
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D'Souza MS. Glutamatergic transmission in drug reward: implications for drug addiction. Front Neurosci 2015; 9:404. [PMID: 26594139 PMCID: PMC4633516 DOI: 10.3389/fnins.2015.00404] [Citation(s) in RCA: 84] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2015] [Accepted: 10/12/2015] [Indexed: 12/12/2022] Open
Abstract
Individuals addicted to drugs of abuse such as alcohol, nicotine, cocaine, and heroin are a significant burden on healthcare systems all over the world. The positive reinforcing (rewarding) effects of the above mentioned drugs play a major role in the initiation and maintenance of the drug-taking habit. Thus, understanding the neurochemical mechanisms underlying the reinforcing effects of drugs of abuse is critical to reducing the burden of drug addiction in society. Over the last two decades, there has been an increasing focus on the role of the excitatory neurotransmitter glutamate in drug addiction. In this review, pharmacological and genetic evidence supporting the role of glutamate in mediating the rewarding effects of the above described drugs of abuse will be discussed. Further, the review will discuss the role of glutamate transmission in two complex heterogeneous brain regions, namely the nucleus accumbens (NAcc) and the ventral tegmental area (VTA), which mediate the rewarding effects of drugs of abuse. In addition, several medications approved by the Food and Drug Administration that act by blocking glutamate transmission will be discussed in the context of drug reward. Finally, this review will discuss future studies needed to address currently unanswered gaps in knowledge, which will further elucidate the role of glutamate in the rewarding effects of drugs of abuse.
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Affiliation(s)
- Manoranjan S D'Souza
- Pharmaceutical and Biomedical Sciences, Raabe College of Pharmacy, Ohio Northern University Ada, OH, USA
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Arndt DL, Johns KC, Dietz ZK, Cain ME. Environmental condition alters amphetamine self-administration: role of the MGluR₅ receptor and schedule of reinforcement. Psychopharmacology (Berl) 2015; 232. [PMID: 26211759 PMCID: PMC4667709 DOI: 10.1007/s00213-015-4031-x] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
RATIONALE Evidence suggests that differential rearing influences the function of a receptor subtype critical for maintaining glutamate homeostasis. Maintaining homeostatic glutamatergic function may be an important protector against drug abuse. OBJECTIVE This study sought to determine if differential rearing influences the function of a receptor critical for glutamate homeostasis, which could in turn affect rates of amphetamine self-administration. METHODS Rats were assigned to enriched (EC), isolated (IC), or standard (SC) conditions. After rearing for 30 days, rats were trained to lever press for sucrose reinforcement before the implantation of indwelling jugular catheters. After reaching stable responding for amphetamine (0.03 or 0.1 mg/kg/infusion), rats were injected with five doses (0, 0.3, 1.0, 3.0, and 5.0 mg/kg) of the mGluR5 antagonist, 3-((2-methyl-1,3-thiazol-4-yl)ethynyl) pyridine hydrochloride (MTEP), 30 min before self-administration sessions. Following fixed-ratio (FR-1) testing, rats were administered identical doses of MTEP on a progressive-ratio (PR) reinforcement schedule. RESULTS MTEP (3.0 mg/kg) attenuated FR-1 self-administration (0.03 mg/kg/infusion) in IC rats. MTEP also dose-dependently attenuated amphetamine self-administration (0.1 mg/kg/infusion) during FR-1 and PR sessions, with 5.0 mg/kg MTEP attenuating amphetamine self-administration in IC and SC rats and 3.0 mg/kg MTEP attenuating amphetamine self-administration in EC and SC rats. PR results also revealed that IC rats not treated with MTEP were more motivated to self-administer the higher dose of amphetamine. CONCLUSIONS These results suggest that the mGlu5 receptor mediates differences in drug-taking behavior among differentially reared rats. Isolation also decreased sensitivity to MTEP, suggesting that environmental factors alter glutamate homeostasis which subsequently affects sensitivity and motivation to self-administer amphetamine.
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Affiliation(s)
- D L Arndt
- Department of Psychological Sciences, Kansas State University, 492 Bluemont Hall, Manhattan, KS, 66506, USA,
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30
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Roohi N, Sarihi A, Shahidi S, Zarei M, Haghparast A. Microinjection of the mGluR5 antagonist MTEP into the nucleus accumbens attenuates the acquisition but not expression of morphine-induced conditioned place preference in rats. Pharmacol Biochem Behav 2014; 126:109-15. [DOI: 10.1016/j.pbb.2014.09.020] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/26/2014] [Revised: 09/18/2014] [Accepted: 09/26/2014] [Indexed: 02/03/2023]
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Perry CJ, Zbukvic I, Kim JH, Lawrence AJ. Role of cues and contexts on drug-seeking behaviour. Br J Pharmacol 2014; 171:4636-72. [PMID: 24749941 PMCID: PMC4209936 DOI: 10.1111/bph.12735] [Citation(s) in RCA: 89] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2013] [Revised: 04/04/2014] [Accepted: 04/10/2014] [Indexed: 01/15/2023] Open
Abstract
Environmental stimuli are powerful mediators of craving and relapse in substance-abuse disorders. This review examined how animal models have been used to investigate the cognitive mechanisms through which cues are able to affect drug-seeking behaviour. We address how animal models can describe the way drug-associated cues come to facilitate the development and persistence of drug taking, as well as how these cues are critical to the tendency to relapse that characterizes substance-abuse disorders. Drug-associated cues acquire properties of conditioned reinforcement, incentive motivation and discriminative control, which allow them to influence drug-seeking behaviour. Using these models, researchers have been able to investigate the pharmacology subserving the behavioural impact of environmental stimuli, some of which we highlight. Subsequently, we examine whether the impact of drug-associated stimuli can be attenuated via a process of extinction, and how this question is addressed in the laboratory. We discuss how preclinical research has been translated into behavioural therapies targeting substance abuse, as well as highlight potential developments to therapies that might produce more enduring changes in behaviour.
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Affiliation(s)
- Christina J Perry
- Behavioural Neuroscience Division, The Florey Institute of Neuroscience and Mental HealthParkville, Vic., Australia
- Florey Department of Neuroscience and Mental Health, University of MelbourneParkville, Vic., Australia
| | - Isabel Zbukvic
- Behavioural Neuroscience Division, The Florey Institute of Neuroscience and Mental HealthParkville, Vic., Australia
- Florey Department of Neuroscience and Mental Health, University of MelbourneParkville, Vic., Australia
| | - Jee Hyun Kim
- Behavioural Neuroscience Division, The Florey Institute of Neuroscience and Mental HealthParkville, Vic., Australia
- Florey Department of Neuroscience and Mental Health, University of MelbourneParkville, Vic., Australia
| | - Andrew J Lawrence
- Behavioural Neuroscience Division, The Florey Institute of Neuroscience and Mental HealthParkville, Vic., Australia
- Florey Department of Neuroscience and Mental Health, University of MelbourneParkville, Vic., Australia
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32
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Pomierny-Chamioło L, Rup K, Pomierny B, Niedzielska E, Kalivas PW, Filip M. Metabotropic glutamatergic receptors and their ligands in drug addiction. Pharmacol Ther 2014; 142:281-305. [DOI: 10.1016/j.pharmthera.2013.12.012] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2013] [Accepted: 12/02/2013] [Indexed: 02/07/2023]
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Arndt DL, Arnold JC, Cain ME. The effects of mGluR2/3 activation on acute and repeated amphetamine-induced locomotor activity in differentially reared male rats. Exp Clin Psychopharmacol 2014; 22:257-65. [PMID: 24467371 PMCID: PMC4041831 DOI: 10.1037/a0035273] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Environmental stimuli play a key role in affecting the likelihood to abuse drugs. Environmental enrichment can reduce that likelihood. The neurotransmitter glutamate contributes to both drug reward and rearing-induced changes in the brain. The current study investigated the effects of the Group-2 metabotropic glutamate receptor (mGluR2/3) agonist, LY-379268 (0.5, 1.0 mg/kg), on acute and repeated amphetamine-induced locomotor activity in differentially reared male rats. Male Sprague-Dawley rats were randomly assigned to one of 3 environmental conditions postweaning: enriched (EC), isolated (IC), or standard (SC), where they reared for 30 days. The effect of LY-379268 on acute amphetamine-induced locomotor activity was assessed. Rats were injected with either LY-379268 (0.5, 1.0 mg/kg) or saline prior to an amphetamine (0.5 mg/kg) or saline challenge injection. Rats were also administered amphetamine (0.5 mg/kg) or saline injections prior to 5 locomotor sessions. Following a rest period of 14-15 days, the effects of repeated amphetamine exposure were evaluated using LY-379268 (0.5, 1.0 mg/kg) or saline injections 30 min prior to receiving amphetamine (0.5 mg/kg). Results showed that LY-379268 administration dose-dependently attenuated acute amphetamine-induced locomotor activity, with EC rats generally displaying less attenuation than IC or SC rats. After repeated amphetamine administrations, the ability of LY-379268 to attenuate the final expression of amphetamine-induced locomotor activity in differentially reared rats was dose-dependent. The differing effect of LY-379268 observed in EC rats suggests enrichment-induced glutamatergic alterations that may protect against sensitivity to psychostimulants.
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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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Keck TM, Zou MF, Bi GH, Zhang HY, Wang XF, Yang HJ, Srivastava R, Gardner EL, Xi ZX, Newman AH. A novel mGluR5 antagonist, MFZ 10-7, inhibits cocaine-taking and cocaine-seeking behavior in rats. Addict Biol 2014; 19:195-209. [PMID: 24001208 DOI: 10.1111/adb.12086] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Pre-clinical studies suggest that negative allosteric modulators (NAMs) of the metabotropic glutamate receptor subtype 5 (mGluR5), including 2-methyl-6-(phenylethynyl)pyridine (MPEP), 3-[(2-methyl-1,3-thiazol-4-yl)ethynyl]pyridine (MTEP) and fenobam are highly effective in attenuating drug-taking and drug-seeking behaviors. However, both MPEP and MTEP have no translational potential for use in humans because of their off-target effects and short half-lives. Here, we report that 3-fluoro-5-[(6-methylpyridin-2-yl)ethynyl]benzonitrile (MFZ 10-7), a novel mGluR5 NAM, is more potent and selective than MPEP, MTEP and fenobam in both in vitro binding and functional assays. Similar to MTEP, intraperitoneal administration of MFZ 10-7 inhibited intravenous cocaine self-administration, cocaine-induced reinstatement of drug-seeking behavior and cocaine-associated cue-induced cocaine-seeking behavior in rats. Although MFZ 10-7 and MTEP lowered the rate of oral sucrose self-administration, they did not alter total sucrose intake. Further, MFZ 10-7 appeared to be more potent than MTEP in inducing downward shifts in the cocaine dose-response curve, but less effective than MTEP in attenuating sucrose-induced reinstatement of sucrose-seeking behavior. MFZ 10-7 and MTEP had no effect on basal locomotor behavior. These findings not only provide additional evidence supporting an important role for mGluR5 in cocaine reward and addiction, but also introduce a new tool for both in vitro and in vivo investigations with which to further characterize this role.
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Affiliation(s)
- Thomas M. Keck
- Medicinal Chemistry Section; Molecular Targets and Medications Discovery Branch; National Institute on Drug Abuse. NIH, DHHS; Baltimore MD USA
| | - Mu-Fa Zou
- Medicinal Chemistry Section; Molecular Targets and Medications Discovery Branch; National Institute on Drug Abuse. NIH, DHHS; Baltimore MD USA
| | - Guo-Hua Bi
- Neuropsychopharmacology Section; Chemical Biology Research Branch; Intramural Research Program; National Institute on Drug Abuse. NIH, DHHS; Baltimore MD USA
| | - Hai-Ying Zhang
- Neuropsychopharmacology Section; Chemical Biology Research Branch; Intramural Research Program; National Institute on Drug Abuse. NIH, DHHS; Baltimore MD USA
| | - Xiao-Fei Wang
- Neuropsychopharmacology Section; Chemical Biology Research Branch; Intramural Research Program; National Institute on Drug Abuse. NIH, DHHS; Baltimore MD USA
| | - Hong-Ju Yang
- Neuropsychopharmacology Section; Chemical Biology Research Branch; Intramural Research Program; National Institute on Drug Abuse. NIH, DHHS; Baltimore MD USA
| | - Ratika Srivastava
- Neuropsychopharmacology Section; Chemical Biology Research Branch; Intramural Research Program; National Institute on Drug Abuse. NIH, DHHS; Baltimore MD USA
| | - Eliot L. Gardner
- Neuropsychopharmacology Section; Chemical Biology Research Branch; Intramural Research Program; National Institute on Drug Abuse. NIH, DHHS; Baltimore MD USA
| | - Zheng-Xiong Xi
- Neuropsychopharmacology Section; Chemical Biology Research Branch; Intramural Research Program; National Institute on Drug Abuse. NIH, DHHS; Baltimore MD USA
| | - Amy Hauck Newman
- Medicinal Chemistry Section; Molecular Targets and Medications Discovery Branch; National Institute on Drug Abuse. NIH, DHHS; Baltimore MD USA
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Martinez D, Slifstein M, Nabulsi N, Grassetti A, Urban N, Perez A, Liu F, Lin SF, Ropchan J, Mao X, Kegeles LS, Shungu DC, Carson RE, Huang Y. Imaging glutamate homeostasis in cocaine addiction with the metabotropic glutamate receptor 5 positron emission tomography radiotracer [(11)C]ABP688 and magnetic resonance spectroscopy. Biol Psychiatry 2014; 75:165-71. [PMID: 24035345 PMCID: PMC4106018 DOI: 10.1016/j.biopsych.2013.06.026] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/04/2013] [Revised: 06/05/2013] [Accepted: 06/28/2013] [Indexed: 12/22/2022]
Abstract
BACKGROUND Preclinical studies demonstrate that glutamate homeostasis in the striatum is disrupted following cocaine exposure, including a decrease in metabotropic glutamate receptor type 5 (mGluR5) expression and reduced glutamate turnover. The goal of this study was to use imaging of the human brain to investigate alterations in the glutamate signaling in cocaine addiction. METHODS Positron emission tomography imaging with the radiotracer [(11)C]ABP688 was used to measure mGluR5 binding and magnetic resonance spectroscopy was used to measure glutamate-glutamine levels in the striatum of cocaine-addicted participants (n = 15) compared with healthy control subjects (n = 15). Following the scans, the cocaine-addicted volunteers performed cocaine self-administration sessions to investigate the correlation between cocaine-seeking behavior and mGluR5 receptor binding. RESULTS The results of the study showed that cocaine addiction was associated with a 20% to 22% reduction in [(11)C]ABP688 binding in the striatum. A secondary analysis of cortical and subcortical regions other than the striatum showed a similar reduction in [(11)C]ABP688 binding, suggesting that the decrease was widespread. No between-group differences were seen in the magnetic resonance spectroscopy measures of glutamate-glutamine in the left striatum. In addition, no correlation was seen between [(11)C]ABP688 binding in the striatum and the choice to self-administer cocaine. CONCLUSIONS Overall, these results show that long-term cocaine use is associated with a decrease in mGluR5 availability compared with matched healthy control subjects and suggests that this receptor may serve as a viable target for treatment development for this disorder.
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Affiliation(s)
- Diana Martinez
- Department of Psychiatry, Columbia University College of Physicians and Surgeons and the New York State Psychiatric Institute, New York, New York.
| | - Mark Slifstein
- Department of Psychiatry, Columbia University College of Physicians and Surgeons and the New York State Psychiatric Institute, New York, NY, USA
| | - Nabeel Nabulsi
- The Department of Psychiatry, Yale PET Center, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Alexander Grassetti
- Department of Psychiatry, Columbia University College of Physicians and Surgeons and the New York State Psychiatric Institute, New York, NY, USA
| | - Nina Urban
- Department of Psychiatry, Columbia University College of Physicians and Surgeons and the New York State Psychiatric Institute, New York, NY, USA
| | - Audrey Perez
- Department of Psychiatry, Columbia University College of Physicians and Surgeons and the New York State Psychiatric Institute, New York, NY, USA
| | - Fei Liu
- Department of Psychiatry, Columbia University College of Physicians and Surgeons and the New York State Psychiatric Institute, New York, NY, USA
| | - Shu-fei Lin
- The Department of Psychiatry, Yale PET Center, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Jim Ropchan
- The Department of Psychiatry, Yale PET Center, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Xiangling Mao
- Department of Radiology, Weill Medical College of Cornell University, New York, NY, USA
| | - Lawrence S. Kegeles
- Department of Psychiatry, Columbia University College of Physicians and Surgeons and the New York State Psychiatric Institute, New York, NY, USA
| | - Dikoma C. Shungu
- Department of Radiology, Weill Medical College of Cornell University, New York, NY, USA
| | - Richard E. Carson
- The Department of Psychiatry, Yale PET Center, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Yiyun Huang
- The Department of Psychiatry, Yale PET Center, Yale University School of Medicine, New Haven, Connecticut, USA
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Li X, Semenova S, D'Souza MS, Stoker AK, Markou A. Involvement of glutamatergic and GABAergic systems in nicotine dependence: Implications for novel pharmacotherapies for smoking cessation. Neuropharmacology 2014; 76 Pt B:554-65. [PMID: 23752091 PMCID: PMC3830589 DOI: 10.1016/j.neuropharm.2013.05.042] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2013] [Revised: 05/14/2013] [Accepted: 05/15/2013] [Indexed: 01/29/2023]
Abstract
Tobacco smoking continues to be a major global health hazard despite significant public awareness of its harmful consequences. Although several treatment options are currently available for smoking cessation, these medications are effective in only a small subset of smokers, and relapse rates continue to be high. Therefore, a better understanding of the neurobiological mechanisms that mediate tobacco dependence is essential for the development of effective smoking cessation medications. Nicotine is the primary psychoactive component of tobacco that drives the harmful tobacco smoking habit. Nicotine binds to nicotinic acetylcholine receptors (nAChRs) in the brain, resulting in the release of a wide range of neurotransmitters, including glutamate and γ-aminobutyric acid (GABA). This review article focuses on the role of the excitatory glutamate system and inhibitory GABA system in nicotine dependence. Accumulating evidence suggests that blockade of glutamatergic transmission or facilitation of GABAergic transmission attenuates the positive reinforcing and incentive motivational aspects of nicotine, inhibits the reward-enhancing and conditioned rewarding effects of nicotine, and blocks nicotine-seeking behavior. Chronic nicotine exposure produced long-term neuroadaptations that contribute to nicotine withdrawal, but the role of GABA and glutamate transmission in nicotine withdrawal is less understood. Overall, the findings presented in this review provide strong converging evidence for the potential effectiveness of glutamatergic and GABAergic medications in nicotine dependence. This article is part of a Special Issue entitled 'NIDA 40th Anniversary Issue'.
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Affiliation(s)
| | | | | | - Astrid K. Stoker
- Department of Psychiatry, School of Medicine, University of California San Diego, La Jolla, CA, USA
| | - Athina Markou
- Department of Psychiatry, School of Medicine, University of California San Diego, La Jolla, CA, USA
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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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Amato RJ, Felts AS, Rodriguez AL, Venable DF, Morrison RD, Byers FW, Daniels JS, Niswender CM, Conn PJ, Lindsley CW, Jones CK, Emmitte KA. Substituted 1-Phenyl-3-(pyridin-2-yl)urea negative allosteric modulators of mGlu5: discovery of a new tool compound VU0463841 with activity in rat models of cocaine addiction. ACS Chem Neurosci 2013; 4:1217-28. [PMID: 23682684 DOI: 10.1021/cn400070k] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Cocaine is a powerful and highly addictive stimulant that disrupts the normal reward circuitry in the central nervous system (CNS), producing euphoric effects. Cocaine use can lead to acute and life threatening emergencies, and abuse is associated with increased risk for contracting infectious diseases. Though certain types of behavioral therapy have proven effective for treatment of cocaine addiction, relapse remains high, and there are currently no approved medications for the treatment of cocaine abuse. Evidence has continued to accumulate that indicates a critical role for the metabotropic glutamate receptor subtype 5 (mGlu5) in the modulation of neural circuitry associated with the addictive properties of cocaine. While the small molecule mGlu5 negative allosteric modulator (NAM) field is relatively advanced, investigation into the potential of small molecule mGlu5 NAMs for the treatment of cocaine addiction remains an area of high interest. Herein we describe the discovery and characterization of a potent and selective compound 29 (VU0463841) with good CNS exposure in rats. The utility of 29 (VU0463841) was demonstrated by its ability to attenuate drug seeking behaviors in relevant rat models of cocaine addiction.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | | | - Carrie K. Jones
- Tennessee
Valley Healthcare System, U.S. Department of Veterans Affairs, Nashville, Tennessee 37212, United States
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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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D'Souza MS, Markou A. The "stop" and "go" of nicotine dependence: role of GABA and glutamate. Cold Spring Harb Perspect Med 2013; 3:3/6/a012146. [PMID: 23732855 DOI: 10.1101/cshperspect.a012146] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Nicotine plays an important role in the initiation and maintenance of tobacco smoking. Importantly, chronic nicotine exposure alters the function of brain reward systems, resulting in the development of a nicotine-dependent state. This nicotine-dependent state is associated with aversive affective and somatic signs upon abstinence from smoking, often leading to relapse in abstinent smokers. This article reviews the role of the major excitatory and inhibitory neurotransmitters glutamate and γ-aminobutyric acid (GABA), respectively, in both the reinforcing effects of nicotine and development of nicotine dependence. Evidence suggests that blockade of glutamatergic neurotransmission attenuates both nicotine intake and nicotine seeking. In contrast, both nicotine intake and nicotine seeking are attenuated when GABA neurotransmission is facilitated. In conclusion, medications that either attenuate/negatively modulate glutamatergic neurotransmission or facilitate/positively modulate GABA neurotransmission may be useful for promoting smoking cessation in humans.
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Affiliation(s)
- Manoranjan S D'Souza
- Department of Psychiatry, School of Medicine, University of California San Diego, La Jolla, California 92093, 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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Managò F, Lopez S, Oliverio A, Amalric M, Mele A, De Leonibus E. Interaction between the mGlu receptors 5 antagonist, MPEP, and amphetamine on memory and motor functions in mice. Psychopharmacology (Berl) 2013. [PMID: 23192313 DOI: 10.1007/s00213-012-2925-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
RATIONALE Metabotropic glutamate mGlu receptors 5 (mGluR5) receptors are abundant in corticolimbic circuitry where they modulate glutamate and dopamine signal transduction. OBJECTIVES In this study, we explored the hypothesis that mGluR5 antagonist, (2-methyl-6-(phenylethynyl)pyridine hydrochloride) (MPEP), facilitates dopamine-dependent effects on memory and motor functions. METHODS To this aim, we examined the effects of different doses (from 0 to 24 mg/kg) of the mGluR5 antagonist, MPEP, on the modulation of amphetamine-dependent behaviors, namely passive avoidance, locomotor activity, and rotation behavior in intact and dopamine-depleted CD1 male mice. RESULTS We demonstrated that a low dose (3 mg/kg) of MPEP, which is void of behavioral effects on its own, facilitates amphetamine-induced effects independently on the behavior measured both in naïve and in dopamine-lesioned mice; this synergistic effect is lost when higher doses of MPEP are used. CONCLUSION The results are discussed in terms of possible balance between dopamine and glutamate activity in regulating the proper fine tuning of information processing.
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Affiliation(s)
- Francesca Managò
- Dipartimento di Biologia e Biotecnologie "C. Darwin", Università degli Studi di Roma "La Sapienza", Rome, Italy
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Abstract
INTRODUCTION The design and development of small molecule negative allosteric modulators (NAMs) of the metabotropic glutamate receptor subtype 5 (mGlu5) has been an area of intense interest for over a decade. Potential roles have been established for mGlu5 NAMs in the treatment of diseases such as pain, anxiety, gastroesophageal reflux disease (GERD), Parkinson's disease levodopa-induced dyskinesia (PD-LID), fragile X syndrome (FXS), autism, addiction, and depression. AREAS COVERED This review begins with an update of the clinical trial efforts with mGlu5 NAMs. Following that update, the review summarizes small molecule mGlu5 NAM patent applications published between 2010 and 2012. These summaries are subdivided into three separate groups: inventions related to improvements in drug properties and/or developability, new chemical entities that contain a disubstituted alkyne, and new chemical entities that do not contain a disubstituted alkyne. EXPERT OPINION Given the abundant promise found within the mGlu5 NAM field, optimism remains that a drug will emerge from this therapeutic class. Still, the launch of a new drug is far from a certainty. It is encouraging to observe the ever-increasing chemical diversity among mGlu5 NAMs. Finally, in spite of the mature nature of this field, room remains for new advancements.
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Affiliation(s)
- Kyle A Emmitte
- Vanderbilt University Medical Center, Vanderbilt Center for Neuroscience Drug Discovery, Department of Chemistry, Nashville, TN 37232, USA.
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Obara I, Goulding SP, Gould AT, Lominac KD, Hu JH, Zhang PW, von Jonquieres G, Dehoff M, Xiao B, Seeburg PH, Worley PF, Klugmann M, Szumlinski KK. Homers at the Interface between Reward and Pain. Front Psychiatry 2013; 4:39. [PMID: 23761764 PMCID: PMC3675508 DOI: 10.3389/fpsyt.2013.00039] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/05/2013] [Accepted: 05/10/2013] [Indexed: 11/13/2022] Open
Abstract
Pain alters opioid reinforcement, presumably via neuroadaptations within ascending pain pathways interacting with the limbic system. Nerve injury increases expression of glutamate receptors and their associated Homer scaffolding proteins throughout the pain processing pathway. Homer proteins, and their associated glutamate receptors, regulate behavioral sensitivity to various addictive drugs. Thus, we investigated a potential role for Homers in the interactions between pain and drug reward in mice. Chronic constriction injury (CCI) of the sciatic nerve elevated Homer1b/c and/or Homer2a/b expression within all mesolimbic structures examined and for the most part, the Homer increases coincided with elevated mGluR5, GluN2A/B, and the activational state of various down-stream kinases. Behaviorally, CCI mice showed pain hypersensitivity and a conditioned place-aversion (CPA) at a low heroin dose that supported conditioned place-preference (CPP) in naïve controls. Null mutations of Homer1a, Homer1, and Homer2, as well as transgenic disruption of mGluR5-Homer interactions, either attenuated or completely blocked low-dose heroin CPP, and none of the CCI mutant strains exhibited heroin-induced CPA. However, heroin CPP did not depend upon full Homer1c expression within the nucleus accumbens (NAC), as CPP occurred in controls infused locally with small hairpin RNA-Homer1c, although intra-NAC and/or intrathecal cDNA-Homer1c, -Homer1a, and -Homer2b infusions (to best mimic CCI's effects) were sufficient to blunt heroin CPP in uninjured mice. However, arguing against a simple role for CCI-induced increases in either spinal or NAC Homer expression for heroin CPA, cDNA infusion of our various cDNA constructs either did not affect (intrathecal) or attenuated (NAC) heroin CPA. Together, these data implicate increases in glutamate receptor/Homer/kinase activity within limbic structures, perhaps outside the NAC, as possibly critical for switching the incentive motivational properties of heroin following nerve injury, which has relevance for opioid psychopharmacology in individuals suffering from neuropathic pain.
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Affiliation(s)
- Ilona Obara
- Department of Psychology, Neuroscience Research Institute, University of California at Santa Barbara Santa Barbara, CA, USA ; School of Medicine, Pharmacy and Health, Queen's Campus, University of Durham Stockton on Tees, UK
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Abstract
In animal models of addiction, reducing glutamate stimulation of the metabotropic glutamate receptor 5 (mGluR5) inhibits drug-seeking. The present study used the reinstatement model of cocaine-seeking to show that blockade of mGluR5 directly in the core subcompartment of the nucleus accumbens (NAcore) prevented both conditioned cue- and cocaine-reinstated drug-seeking. Consistent with this finding, microinjection of the mGluR5 agonist (RS)-2-chloro-5-hydroxyphenylglycine into the NAcore produced modest reinstatement of lever pressing when given alone and significantly potentiated cue-induced reinstatement. Homer proteins are contained in the post-synaptic density and regulate mGluR5 intracellular signaling and trafficking to the membrane. Microinjecting a membrane permeable peptide antagonist of Homer binding to mGluR5 into the NAcore also inhibited cue- and cocaine-reinstated lever pressing. However, this peptide did not change the surface expression of mGluR5, indicating that the peptide inhibitor did not alter the surface trafficking of mGluR5. Taken together, these data show that mGluR5 inhibition and stimulation in the NAcore can regulate cocaine-seeking, and demonstrate that one mechanism for this effect is via interactions with Homer proteins.
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Affiliation(s)
- Xiusong Wang
- Department of Neurosciences, Medical University of South Carolina, Charleston, SC 29425, USA
| | - Kahled Moussawi
- Department of Neurosciences, Medical University of South Carolina, Charleston, SC 29425, USA
| | - Lori Knackstedt
- Department of Neurosciences, Medical University of South Carolina, Charleston, SC 29425, USA
| | - Haowei Shen
- Department of Neurosciences, Medical University of South Carolina, Charleston, SC 29425, USA
| | - Peter W. Kalivas
- Department of Neurosciences, Medical University of South Carolina, Charleston, SC 29425, USA
- Department of Psychiatry and Behavioral Sciences, Medical University of South Carolina, Charleston, SC 29425, USA
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Love and addiction: the devil is in the differences: a commentary on "the behavioral, anatomical and pharmacological parallels between social attachment, love and addiction". Psychopharmacology (Berl) 2012; 224:27-9; discussion 31-2. [PMID: 22948669 DOI: 10.1007/s00213-012-2858-y] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/16/2012] [Accepted: 08/23/2012] [Indexed: 10/27/2022]
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mGlu5 and adenosine A2A receptor interactions regulate the conditioned effects of cocaine. Int J Neuropsychopharmacol 2012; 15:995-1001. [PMID: 21816123 DOI: 10.1017/s146114571100126x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Adenosine A2A receptors and metabotropic glutamate type 5 (mGlu5) receptors are co-localized in the striatum and can functionally interact to regulate drug-seeking. We further explored this interaction using antagonism of mGlu5 receptors with 3-[(2-methyl-1,3-thiazol-4-yl)ethynyl]-pyridine (MTEP) in combination with genetic deletion of A2A receptors. The conditioned rewarding and locomotor-activating properties of cocaine were evaluated via conditioned place preference (CPP). Vehicle-treated mice of both genotypes expressed a CPP to cocaine while MTEP abolished cocaine CPP in wild-type, but not A2A knockout, mice. These results were mirrored when conditioned hyperactivity was assessed. In contrast, MTEP attenuated the acute locomotor-activating properties of cocaine similarly in both genotypes. These data provide evidence for a functional interaction between adenosine A2A and mGlu5 receptors in mediating the conditioned effects of cocaine but not direct cocaine-induced hyperactivity. This functional interaction is supported by modulation of 4-(2-[7-amino-2-[2-furyl][1,2,4]triazolol[2,3-a][1,3,5]triazin-5-yl-amino]ethyl)phenol ([125I]ZM241385) binding to the A2A receptor by MTEP.
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Schwendt M, Sigmon SA, McGinty JF. RGS4 overexpression in the rat dorsal striatum modulates mGluR5- and amphetamine-mediated behavior and signaling. Psychopharmacology (Berl) 2012; 221:621-35. [PMID: 22193724 PMCID: PMC4507824 DOI: 10.1007/s00213-011-2606-8] [Citation(s) in RCA: 28] [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] [Accepted: 11/30/2011] [Indexed: 12/14/2022]
Abstract
RATIONALE Regulator of G-protein signaling 4 (RGS4) is a brain-enriched negative modulator of G-protein-coupled receptor signaling. Decreased availability of RGS4 in the frontal cortex and striatum has been described in animal models of schizophrenia and drug addiction. However, cellular and behavioral consequences of dysregulated RGS4-dependent receptor signaling in the brain remain poorly understood. OBJECTIVE This study aims to investigate whether RGS4, through inhibiting the function of mGluR5 receptors in the dorsal striatum (dSTR), regulates cellular and behavioral responses to acute amphetamine. METHODS After herpes simplex virus-RGS4 was infused into the dSTR, RGS4 overexpression as well as binding of recombinant RGS4 to mGluR5 was assessed. The effect of RGS4 overexpression on behavioral activity induced by the intrastriatal mGluR5 agonist, DHPG, or amphetamine was recorded. Activation of extracellular signal-regulated kinase (ERK) and Akt (protein kinase B) was measured in the dSTR tissue at the end of each behavioral experiment. RESULTS RGS4 overexpressed in the dSTR coimmunoprecipitated with mGluR5 receptors and suppressed both behavioral activity and phospho-ERK levels induced by DHPG. RGS4 overexpression or the mGluR5 antagonist, 3-((2-methyl-4-thiazolyl)ethynyl)pyridine (MTEP), attenuated amphetamine-induced phospho-ERK (but not phospho-Akt) levels. RGS4 suppressed amphetamine-induced vertical activity and augmented horizontal activity over 90 min. Similarly, MTEP augmented amphetamine-induced horizontal activity, but did not affect vertical activity. CONCLUSIONS The present data demonstrate that RGS4 in the dSTR attenuates amphetamine-induced ERK signaling and decreases the behavioral efficacy of acute amphetamine likely by limiting mGluR5 function.
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Affiliation(s)
| | | | - Jacqueline F. McGinty
- Address all correspondence and reprint requests to: Jacqueline McGinty, Ph.D., Department of Neurosciences, Medical University of South Carolina, 173 Ashley Avenue, BSB 403, MSC 510, Charleston, SC 29425-5100, tel 843-792-9036, fax 843-792-4423,
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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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