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Contó MB, Pautassi RM, Camarini R. Rewarding and Antidepressant Properties of Ketamine and Ethanol: Effects on the Brain-Derived Neurotrophic Factor and TrkB and p75 NTR Receptors. Neuroscience 2022; 493:1-14. [PMID: 35469972 DOI: 10.1016/j.neuroscience.2022.04.015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2022] [Revised: 04/12/2022] [Accepted: 04/18/2022] [Indexed: 10/18/2022]
Abstract
There is a high level of comorbidity between depression and alcohol use disorder. Subanesthetic doses of ketamine induce short-acting and enduring antidepressant effects after a single or a few administrations. Considering such comorbidity, we assessed, in Swiss male mice, if ketamine-induced antidepressant-like effects would alter ethanol's rewarding effects; and, if ethanol pretreatment would alter the rewarding and antidepressant effects of ketamine. The role of the brain-derived neurotrophic factor (BDNF) and its high and low affinity receptors TrkB and p75NTR, respectively, in both reward and depression-related behaviors is well established. The present study assessed, in outbred Swiss male mice, the expression of these proteins in the prefrontal cortex and hippocampus. Ketamine did not alter the development of ethanol-induced conditioned place preference (CPP), yet ethanol inhibited the expression of CPP induced by 50 mg/kg ketamine. The antidepressant action of 50 mg/kg ketamine was attenuated after repeated treatment (i.e., developed tolerance), an effect blocked by ethanol preexposure; ethanol also inhibited the antidepressant effect of 30 mg/kg ketamine. Ketamine (50 mg/kg) and Ethanol-Ketamine (50 mg/kg) groups showed lower levels of 145 kDa TrkB in the hippocampus than Saline-treated group. Ethanol-Ketamine (50 mg/kg) decreased the hippocampal expression of p75NTR compared to Saline-Saline and Saline-Ethanol groups. Ketamine (50 mg/kg) induced hippocampal downregulation of 145 kDa TrkB may contribute to ketamine-induced antidepressant tolerance. Likewise, a relationship between low hippocampal levels of p75NTR in the Ethanol-Ketamine (50 mg/kg) and ketamine-induced CPP blockade may be considered. The findings underscore potential ethanol-ketamine interactions likely to undermine ketamine putative antidepressant effects.
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Affiliation(s)
- Marcos Brandão Contó
- Departamento de Farmacologia, Instituto de Ciências Biomédicas, Universidade de São Paulo, São Paulo 05508-900, Brasil.
| | - Ricardo Marcos Pautassi
- Instituto de Investigación Médica M. y M. Ferreyra (INIMEC-CONICET-Universidad Nacional de Córdoba), Córdoba C.P. 5000, Argentina; Facultad de Psicología, Universidad Nacional de Córdoba, Córdoba C.P. 5000 Argentina
| | - Rosana Camarini
- Departamento de Farmacologia, Instituto de Ciências Biomédicas, Universidade de São Paulo, São Paulo 05508-900, Brasil.
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Morley KC, Perry CJ, Watt J, Hurzeler T, Leggio L, Lawrence AJ, Haber P. New approved and emerging pharmacological approaches to alcohol use disorder: a review of clinical studies. Expert Opin Pharmacother 2021; 22:1291-1303. [PMID: 33615945 DOI: 10.1080/14656566.2021.1892641] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
introduction: The number of medications approved for AUD is small and they generally have limited efficacy. We need new pharmacotherapies for the management of AUD.Areas covered: In this review, the authors aim to synthesise literature for new approved and emerging pharmacotherapies for AUD. Recently approved medications include nalmefene, which was approved in Europe and Australia for the purposes of controlled drinking. Baclofen has also been approved in France but not in other countries. Off label medications including topiramate and gabapentin have received significant attention with multiple RCTs and meta-analyses and have widespread use in several countries including the USA. Several novel medications have emerged over the last decade but further work is required to determine their efficacy and safety for the widespread management of AUD.Expert opinion: Despite significant advances in our understanding of the neurobiological basis of factors that contribute to the development and maintenance of AUD, there have been few new AUD medications approved for almost 20 years. There are many challenges to the development and introduction of new pharmacotherapies for AUD. Strategies for improving the translational pipeline include drug repurposing and utilisation of human acute laboratory models.
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Affiliation(s)
- Kirsten C Morley
- Central Clinical School, Sydney School of Medicine, Faculty of Medicine & Health, University of Sydney, NSW, Australia.,Edith Collins Centre (Alcohol, Drugs and Toxicology), Sydney Local Health District, Royal Prince Alfred Hospital, Camperdown, NSW, Australia
| | - Christina J Perry
- University of Melbourne, Mental Health Theme, Florey Institute of Neuroscience and Mental Health, Parkville, Australia
| | - Joshua Watt
- Edith Collins Centre (Alcohol, Drugs and Toxicology), Sydney Local Health District, Royal Prince Alfred Hospital, Camperdown, NSW, Australia
| | - Tristan Hurzeler
- Central Clinical School, Sydney School of Medicine, Faculty of Medicine & Health, University of Sydney, NSW, Australia
| | - Lorenzo Leggio
- Clinical Psychoneuroendocrinology and Neuropsychopharmacology Section, National Institute on Drug Abuse and National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Baltimore and Bethesda, USA.,Department of Neuroscience, Georgetown University Medical Center, Washington, USA.,Medication Development Program, National Institute on Drug Abuse Intramural Research Program, National Institutes of Health, Baltimore, USA
| | - Andrew J Lawrence
- University of Melbourne, Mental Health Theme, Florey Institute of Neuroscience and Mental Health, Parkville, Australia.,Center for Alcohol and Addiction Studies, Department of Behavioral and Social Sciences, School of Public Health, Brown University, Providence, USA
| | - Paul Haber
- Central Clinical School, Sydney School of Medicine, Faculty of Medicine & Health, University of Sydney, NSW, Australia.,Edith Collins Centre (Alcohol, Drugs and Toxicology), Sydney Local Health District, Royal Prince Alfred Hospital, Camperdown, NSW, Australia.,Division of Addiction Medicine, Department of Medicine, School of Medicine, Johns Hopkins University, Baltimore, USA
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Effects of N-acetylcysteine treatment on ethanol's rewarding properties and dopaminergic alterations in mesocorticolimbic and nigrostriatal pathways. Behav Pharmacol 2020; 32:239-250. [PMID: 33290342 DOI: 10.1097/fbp.0000000000000613] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Recent reports have shown that N-acetylcysteine (N-AC) has beneficial effects in the treatment of cocaine and nicotine abuse. Considering the similar neurobiologic mechanisms involved in the development of addiction to different drugs, N-AC treatment could be useful in the treatment of ethanol abuse. The rewarding properties of the drugs of abuse plays an important role in the development of addiction and can be studied using the conditioned place preference (CPP) paradigm. Thus, to study the effects of N-AC treatment in the rewarding effects of ethanol, we investigated the effects of N-AC administration in the ethanol-induced CPP and neurochemical alterations within the mesocorticolimbic and the nigrostriatal dopaminergic pathways. Adult male Swiss mice were pretreated with N-AC (60 or 120 mg/kg intraperitoneal) and tested for the development, expression, or extinction of the ethanol-induced CPP. Another cohort of animals received N-AC (60 or 120 mg/kg intraperitoneal) 2-h before an acute administration of ethanol and had their brains removed for dopamine and its metabolites quantification in the mesocorticolimbic and nigrostriatal pathways. Pretreatment with N-AC (120 mg/kg) blocked the development of ethanol-induced CPP. On the other hand, N-AC at both doses did not alter the expression nor the extinction of ethanol-induced CPP. N-AC increased 3,4-dihydroxyphenylacetic acid content in the medial prefrontal cortex and dopaminergic turnover within the substantia nigra. Besides that, there was an increase in dopamine content in the nucleus accumbens of ethanol-treated animals. In summary, N-AC treatment blocked the development of ethanol CPP, without altering ethanol effects on dopaminergic neurotransmission.
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Alasmari F, Alhaddad H, Wong W, Bell RL, Sari Y. Ampicillin/Sulbactam Treatment Modulates NMDA Receptor NR2B Subunit and Attenuates Neuroinflammation and Alcohol Intake in Male High Alcohol Drinking Rats. Biomolecules 2020; 10:biom10071030. [PMID: 32664441 PMCID: PMC7407831 DOI: 10.3390/biom10071030] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2020] [Revised: 07/06/2020] [Accepted: 07/09/2020] [Indexed: 12/21/2022] Open
Abstract
Exposure to ethanol commonly manifests neuroinflammation. Beta (β)-lactam antibiotics attenuate ethanol drinking through upregulation of astroglial glutamate transporters, especially glutamate transporter-1 (GLT-1), in the mesocorticolimbic brain regions, including the nucleus accumbens (Acb). However, the effect of β-lactam antibiotics on neuroinflammation in animals chronically exposed to ethanol has not been fully investigated. In this study, we evaluated the effects of ampicillin/sulbactam (AMP/SUL, 100 and 200 mg/kg, i.p.) on ethanol consumption in high alcohol drinking (HAD1) rats. Additionally, we investigated the effects of AMP/SUL on GLT-1 and N-methyl-d-aspartate (NMDA) receptor subtypes (NR2A and NR2B) in the Acb core (AcbCo) and Acb shell (AcbSh). We found that AMP/SUL at both doses attenuated ethanol consumption and restored ethanol-decreased GLT-1 and NR2B expression in the AcbSh and AcbCo, respectively. Moreover, AMP/SUL (200 mg/kg, i.p.) reduced ethanol-increased high mobility group box 1 (HMGB1) and receptor for advanced glycation end-products (RAGE) expression in the AcbSh. Moreover, both doses of AMP/SUL attenuated ethanol-elevated tumor necrosis factor-alpha (TNF-α) in the AcbSh. Our results suggest that AMP/SUL attenuates ethanol drinking and modulates NMDA receptor NR2B subunits and HMGB1-associated pathways.
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Affiliation(s)
- Fawaz Alasmari
- Department of Pharmacology and Toxicology, College of Pharmacy, King Saud University, Riyadh 11451, Saudi Arabia;
- Department of Pharmacology and Experimental Therapeutics, University of Toledo, College of Pharmacy and Pharmaceutical Sciences, Toledo, OH 43614, USA; (H.A.); (W.W.)
| | - Hasan Alhaddad
- Department of Pharmacology and Experimental Therapeutics, University of Toledo, College of Pharmacy and Pharmaceutical Sciences, Toledo, OH 43614, USA; (H.A.); (W.W.)
| | - Woonyen Wong
- Department of Pharmacology and Experimental Therapeutics, University of Toledo, College of Pharmacy and Pharmaceutical Sciences, Toledo, OH 43614, USA; (H.A.); (W.W.)
| | - Richard L. Bell
- Department of Psychiatry and Institute of Psychiatric Research, Indiana University School of Medicine, Indianapolis, IN 46202, USA
- Correspondence: (R.L.B.); (Y.S.); Tel.: +317-278-8407 (R.L.B.); +419-383-1507 (Y.S.)
| | - Youssef Sari
- Department of Pharmacology and Experimental Therapeutics, University of Toledo, College of Pharmacy and Pharmaceutical Sciences, Toledo, OH 43614, USA; (H.A.); (W.W.)
- Correspondence: (R.L.B.); (Y.S.); Tel.: +317-278-8407 (R.L.B.); +419-383-1507 (Y.S.)
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Campos-Jurado Y, Martí-Prats L, Morón JA, Polache A, Granero L, Hipólito L. Dose-dependent induction of CPP or CPA by intra-pVTA ethanol: Role of mu opioid receptors and effects on NMDA receptors. Prog Neuropsychopharmacol Biol Psychiatry 2020; 100:109875. [PMID: 31978422 PMCID: PMC7096259 DOI: 10.1016/j.pnpbp.2020.109875] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/03/2019] [Revised: 01/16/2020] [Accepted: 01/21/2020] [Indexed: 12/16/2022]
Abstract
The neurobiological mechanisms underlying alcohol motivational properties are still not fully understood, however, the mu-opioid receptors (MORs) have been evidenced as central elements in the manifestation of the alcohol reinforcing properties. Drug-associated environmental stimuli can trigger alcohol relapse and promote alcohol consumption whereby N-methyl-d-aspartate (NMDA) receptors play a pivotal role. Here we sought to demonstrate, for the first time, that ethanol induces conditioned place preference or aversion (CPP or CPA) when administered locally into the ventral tegmental area (VTA) and the associated role of MORs. We further analyzed the changes in the expression and mRNA levels of GluN1 and GluN2A subunits in designated brain areas. The expression of CPP or CPA was characterized following intra-VTA ethanol administration and we showed that either reinforcing (CPP) or aversive (CPA) properties are dependent on the dose administered (ranging here from 35 to 300 nmol). Furthermore, the critical contribution of local MORs in the acquisition of CPP was revealed by a selective antagonist, namely β-Funaltrexamine. Finally, modifications of the expression of NMDA receptor subunits in the Nucleus Accumbens (NAc) and Hippocampus after ethanol-induced CPP were analyzed at the proteomic and transcriptomic levels by western blot and In Situ Hybridation RNAscope techniques, respectively. Results showed that the mRNA levels of GluN2A but not GluN1 in NAc are higher after ethanol CPP. These novel results pave the way for further characterisation of the mechanisms by which ethanol motivational properties are associated with learned environmental cues.
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Affiliation(s)
- Yolanda Campos-Jurado
- Department of Pharmacy and Pharmaceutical Tech. and Parasit., University of València, Spain
| | - Lucía Martí-Prats
- Department of Pharmacy and Pharmaceutical Tech. and Parasit., University of València, Spain
| | - Jose A Morón
- Department of Anesthesiology, Washington University Pain Center, Washington University in St. Louis, School of Medicine, St. Louis, MO 63110, USA; Department of Neuroscience, Washington University in St. Louis, St. Louis, MO 63110, USA
| | - Ana Polache
- Department of Pharmacy and Pharmaceutical Tech. and Parasit., University of València, Spain
| | - Luis Granero
- Department of Pharmacy and Pharmaceutical Tech. and Parasit., University of València, Spain
| | - Lucía Hipólito
- Department of Pharmacy and Pharmaceutical Tech. and Parasit., University of València, Spain.
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Barajaz AM, Kliethermes CL. An assessment of the utilization of the preclinical rodent model literature in clinical trials of putative therapeutics for the treatment of alcohol use disorders. Drug Alcohol Depend 2017; 181:77-84. [PMID: 29035708 DOI: 10.1016/j.drugalcdep.2017.09.022] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/26/2017] [Revised: 09/11/2017] [Accepted: 09/12/2017] [Indexed: 10/18/2022]
Abstract
OBJECTIVE Rodent models of Alcohol Use Disorders (AUD) are used extensively by preclinical researchers to develop new therapeutics for the treatment of AUD. Although these models play an important role in the development of novel, targeted therapeutics, their role in bringing therapeutics to clinical trials is unclear, as off-label use of existing medications not approved for the treatment of AUD is commonly seen in the clinic and clinical trials. METHOD In the current study, we used the Clinicaltrials.gov database to obtain a list of drugs that have been tested for efficacy in a clinical trial between 1997 and 2017. We then conducted a set of literature searches to determine which of the 98 unique drugs we identified had shown efficacy in a rodent model of an AUD prior to being tested in a clinical trial. RESULTS We found that slightly less than half of the drugs tested in clinical trials (48%) had shown prior efficacy in any rodent model of an AUD, while the remaining 52% of drugs were used off-label, or in some cases, following non-published studies. CONCLUSION This study raises the question of how clinical researchers incorporate results from preclinical studies in the decision to bring a drug to a clinical trial. Our results underscore the need for ongoing communication among preclinical and clinical researchers.
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Affiliation(s)
- Ashley M Barajaz
- Drake University, Department of Psychology and Neuroscience, 1344 27th Street, Des Moines, IA 50311, United States
| | - Christopher L Kliethermes
- Drake University, Department of Psychology and Neuroscience, 1344 27th Street, Des Moines, IA 50311, United States.
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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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Radke AK, Jury NJ, Delpire E, Nakazawa K, Holmes A. Reduced ethanol drinking following selective cortical interneuron deletion of the GluN2B NMDA receptors subunit. Alcohol 2017; 58:47-51. [PMID: 28109345 DOI: 10.1016/j.alcohol.2016.07.005] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2015] [Revised: 05/24/2016] [Accepted: 07/11/2016] [Indexed: 01/09/2023]
Abstract
N-Methyl-d-aspartate receptors (NMDAR) are involved in the regulation of alcohol drinking, but the contribution of NMDAR subunits located on specific neuronal populations remains incompletely understood. The current study examined the role of GluN2B-containing NMDARs expressed on cortical principal neurons and cortical interneurons in mouse ethanol drinking. Consumption of escalating concentrations of ethanol was measured in mice with GluN2B gene deletion in either cortical principal neurons (GluN2BCxNULL) or interneurons (GluN2BInterNULL), using a two-bottle choice paradigm. Results showed that GluN2BInterNULL, but not GluN2BCxNULL, mice consumed significantly less ethanol, at relatively high concentrations, than non-mutant controls. In a second paradigm in which mice were offered a 15% ethanol concentration, without escalation, GluN2BCxNULL mice were again no different from controls. These findings provide novel evidence for a contribution of interneuronal GluN2B-containing NMDARs in the regulation of ethanol drinking.
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Affiliation(s)
- Anna K Radke
- Laboratory of Behavioral and Genomic Neuroscience, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, MD, USA.
| | - Nicholas J Jury
- Laboratory of Behavioral and Genomic Neuroscience, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, MD, USA
| | - Eric Delpire
- Departments of Anesthesiology and Molecular Physiology & Biophysics, Vanderbilt University School of Medicine, Nashville, TN, USA
| | - Kazu Nakazawa
- Department of Psychiatry and Behavioral Neurobiology, University of Alabama at Birmingham School of Medicine, Birmingham, AL, USA
| | - Andrew Holmes
- Laboratory of Behavioral and Genomic Neuroscience, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, MD, USA
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Hopf FW. Do specific NMDA receptor subunits act as gateways for addictive behaviors? GENES BRAIN AND BEHAVIOR 2016; 16:118-138. [PMID: 27706932 DOI: 10.1111/gbb.12348] [Citation(s) in RCA: 52] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 07/05/2016] [Revised: 09/27/2016] [Accepted: 10/03/2016] [Indexed: 12/19/2022]
Abstract
Addiction to alcohol and drugs is a major social and economic problem, and there is considerable interest in understanding the molecular mechanisms that promote addictive drives. A number of proteins have been identified that contribute to expression of addictive behaviors. NMDA receptors (NMDARs), a subclass of ionotropic glutamate receptors, have been of particular interest because their physiological properties make them an attractive candidate for gating induction of synaptic plasticity, a molecular change thought to mediate learning and memory. NMDARs are generally inactive at the hyperpolarized resting potentials of many neurons. However, given sufficient depolarization, NMDARs are activated and exhibit long-lasting currents with significant calcium permeability. Also, in addition to stimulating neurons by direct depolarization, NMDARs and their calcium signaling can allow strong and/or synchronized inputs to produce long-term changes in other molecules (such as AMPA-type glutamate receptors) which can last from days to years, binding internal and external stimuli in a long-term memory trace. Such memories could allow salient drug-related stimuli to exert strong control over future behaviors and thus promote addictive drives. Finally, NMDARs may themselves undergo plasticity, which can alter subsequent neuronal stimulation and/or the ability to induce plasticity. This review will address recent and past findings suggesting that NMDAR activity promotes drug- and alcohol-related behaviors, with a particular focus on GluN2B subunits as possible central regulators of many addictive behaviors, as well as newer studies examining the importance of non-canonical NMDAR subunits and endogenous NMDAR cofactors.
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Affiliation(s)
- F W Hopf
- Alcohol and Addiction Research Group, Department of Neurology, University of California at San Francisco, San Francisco, CA, USA
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Talbot JN, Geffert LM, Jorvig JE, Goldstein RI, Nielsen CL, Wolters NE, Amos ME, Munro CA, Dallman E, Mereu M, Tanda G, Katz JL, Indarte M, Madura JD, Choi H, Leak RK, Surratt CK. Rapid and sustained antidepressant properties of an NMDA antagonist/monoamine reuptake inhibitor identified via transporter-based virtual screening. Pharmacol Biochem Behav 2016; 150-151:22-30. [DOI: 10.1016/j.pbb.2016.08.007] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/03/2016] [Revised: 08/23/2016] [Accepted: 08/24/2016] [Indexed: 01/08/2023]
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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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12
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Krishnan-Sarin S, O'Malley SS, Franco N, Cavallo DA, Morean M, Shi J, Pittman B, Krystal JH. N-methyl-D-aspartate receptor antagonism has differential effects on alcohol craving and drinking in heavy drinkers. Alcohol Clin Exp Res 2015; 39:300-7. [PMID: 25664775 DOI: 10.1111/acer.12619] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2014] [Accepted: 10/28/2014] [Indexed: 11/28/2022]
Abstract
BACKGROUND The objective of this study was to determine the effects of the N-methyl-d-aspartate (NMDA) receptor antagonist, memantine (0, 20, 40 mg/d), upon alcohol drinking and craving in heavy drinkers with or without a family history (FH) of alcoholism, and to explore the modulatory influence of the presence of impulsivity on these outcomes. METHODS Ninety-two, nontreatment-seeking, heavy drinkers received memantine or placebo for 8 days. On the eighth day, they received a priming dose of alcohol followed by a 3-hour period of alcohol access. RESULTS Memantine at a dose of 20 mg reduced alcohol craving but did not influence alcohol drinking. No effects of FH were observed. In participants with higher baseline levels of impulsivity, 40 mg of memantine reduced alcohol craving but increased alcohol drinking and alcohol-induced stimulation. CONCLUSIONS NMDA receptor signaling may play divergent roles in mediating alcohol cue-induced craving and alcohol drinking in heavy drinkers. The potential efficacy of memantine as monotherapy for alcohol use disorders may be limited by its tendency to disinhibit drinking in some individuals.
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Smith KL, John CS, Sypek EI, Ongür D, Cohen BM, Barry SM, Bechtholt AJ. Exploring the role of central astrocytic glutamate uptake in ethanol reward in mice. Alcohol Clin Exp Res 2014; 38:1307-14. [PMID: 24655029 DOI: 10.1111/acer.12361] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2013] [Accepted: 12/18/2013] [Indexed: 01/16/2023]
Abstract
BACKGROUND Alcoholism is associated with specific brain abnormalities revealed through postmortem studies, including a reduction in glial cell number and dysregulated glutamatergic neurotransmission. Whether these abnormalities contribute to the etiology of alcoholism, are consequences of alcohol use, or both is still unknown. METHODS We investigated the role of astrocytic glutamate uptake in ethanol (EtOH) binge drinking in mice, using the "drinking in the dark" (DID) paradigm by blocking the astrocytic glutamate transporter (GLT-1) with intracerebroventricular (ICV) administration of dihydrokainic acid (DHK). To determine whether astrocytic glutamate uptake regulates the conditioned rewarding effects of EtOH, we examined the effects of ICV DHK on the acquisition and expression of EtOH-induced conditioned place preference. RESULTS Blocking central astrocytic glutamate uptake selectively attenuated EtOH binge drinking behavior in mice. DHK did not alter the acquisition or expression of preference for EtOH-associated cues, indicating that reduced astrocytic glutamate trafficking may decrease binge-like drinking without altering the conditioned rewarding effects of EtOH. CONCLUSIONS Several alternative conclusions are plausible, however, interpreting these data in the context of the human literature, these findings suggest that the reduction of glia in the alcoholic brain may not be a predisposing factor to developing alcoholism and could be a consequence of EtOH toxicity that decreases excessive EtOH intake.
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Affiliation(s)
- Karen L Smith
- Department of Psychiatry, Harvard Medical School, McLean Hospital, Belmont, Massachusetts; Laboratory of Addictive Disorders, Department of Pharmacology and Experimental Therapeutics, Boston University School of Medicine, Boston, Massachusetts
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Dreumont SE, Cunningham CL. Effects of acute withdrawal on ethanol-induced conditioned place preference in DBA/2J mice. Psychopharmacology (Berl) 2014; 231:777-85. [PMID: 24096534 PMCID: PMC3910420 DOI: 10.1007/s00213-013-3291-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/14/2013] [Accepted: 09/12/2013] [Indexed: 11/26/2022]
Abstract
RATIONALE Reexposure to ethanol during acute withdrawal might facilitate the transition to alcoholism by enhancing the rewarding effect of ethanol. OBJECTIVE The conditioned place preference (CPP) procedure was used to test whether ethanol reward is enhanced during acute withdrawal. METHODS DBA/2J mice were exposed to an unbiased one-compartment CPP procedure. Ethanol (0.75, 1.0, or 1.5 g/kg IP) was paired with a distinctive floor cue (CS+), whereas saline was paired with a different floor cue (CS-). The withdrawal (W) group received CS+ trials during acute withdrawal produced by a large dose of ethanol (4 g/kg) given 8 h before each trial. The no-withdrawal (NW) group did not experience acute withdrawal during conditioning trials but was matched for acute withdrawal experience. Floor preference was tested in the absence of ethanol or acute withdrawal. RESULTS All groups eventually showed a dose-dependent preference for the ethanol-paired cue, but development of CPP was generally more rapid and stable in the W groups than in the NW groups. Acute withdrawal suppressed the normal activating effect of ethanol during CS+ trials, but there were no group differences in test activity. CONCLUSIONS Acute withdrawal enhanced ethanol's rewarding effect as indexed by CPP. Since this effect depended on ethanol exposure during acute withdrawal, the enhancement of ethanol reward was likely mediated by the alleviation of acute withdrawal, i.e., negative reinforcement. Enhancement of ethanol reward during acute withdrawal may be a key component in the shift from episodic to chronic ethanol consumption that characterizes alcoholism.
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Affiliation(s)
- Sarah E Dreumont
- Department of Behavioral Neuroscience and Portland Alcohol Research Center, Oregon Health & Science University, Portland, OR, 97239-3098, USA
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Abstract
RATIONALE An increasingly compelling literature points to a major role for the glutamate system in mediating the effects of alcohol on behavior and the pathophysiology of alcoholism. Preclinical studies indicate that glutamate signaling mediates certain aspects of ethanol's intoxicating and rewarding effects, and undergoes adaptations following chronic alcohol exposure that may contribute to the withdrawal, craving and compulsive drug-seeking that drive alcohol abuse and alcoholism. OBJECTIVES We discuss the potential for targeting the glutamate system as a novel pharmacotherapeutic approach to treating alcohol use disorders, focusing on five major components of the glutamate system: the N-methyl-D-aspartate (NMDA) receptor and specific NMDA subunits, the glycineB site on the NMDA receptors (NMDAR), L-alpha-amino-3-hydroxy-5-methyl-isoxazole-4-propionic acid ionotropic (AMPA) and kainate (KAR) receptors, metabotropic receptors (mGluR), and glutamate transporters. RESULTS Chronic alcohol abuse produces a hyperglutamatergic state, characterized by elevated extracellular glutamate and altered glutamate receptors and transporters. Pharmacologically manipulating glutamatergic neurotransmission alters alcohol-related behaviors including intoxication, withdrawal, and alcohol-seeking, in rodents and human subjects. Blocking NMDA and AMPA receptors reduces alcohol consumption in rodents, but side-effects may limit this as a therapeutic approach. Selectively targeting NMDA and AMPA receptor subunits (e.g., GluN2B, GluA3), or the NMDAR glycineB site offers an alternative approach. Blocking mGluR5 potently affects various alcohol-related behaviors in rodents, and mGluR2/3 agonism also suppresses alcohol consumption. Finally, glutamate transporter upregulation may mitigate behavioral and neurotoxic sequelae of excess glutamate caused by alcohol. CONCLUSIONS Despite the many challenges that remain, targeting the glutamate system offers genuine promise for developing new treatments for alcoholism.
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Sabino V, Narayan AR, Zeric T, Steardo L, Cottone P. mTOR activation is required for the anti-alcohol effect of ketamine, but not memantine, in alcohol-preferring rats. Behav Brain Res 2013; 247:9-16. [PMID: 23466691 DOI: 10.1016/j.bbr.2013.02.030] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2013] [Revised: 02/23/2013] [Accepted: 02/25/2013] [Indexed: 02/06/2023]
Abstract
Glutamate NMDA receptors mediate many molecular and behavioral effects of alcohol, and they play a key role in the development of excessive drinking. Uncompetitive NMDA receptor antagonists may, therefore, have therapeutic potential for alcoholism. The first aim was to compare the effects of the NMDA antagonists memantine and ketamine on ethanol and saccharin drinking in alcohol-preferring rats. The second aim was to determine whether the effects of the two NMDA receptor antagonists were mediated by the mammalian target of rapamycin (mTOR). TSRI Sardinian alcohol-preferring rats were allowed to self-administer either 10% w/v ethanol or 0.08% w/v saccharin, and water. Operant responding and motor activity were assessed following administration of either memantine (0-10mg/kg) or ketamine (0-20mg/kg). Finally, ethanol self-administration was assessed in rats administered with either memantine or ketamine but pretreated with the mTOR inhibitor rapamycin (2.5mg/kg). The uncompetitive NMDA receptor antagonists memantine and ketamine dose-dependently reduced ethanol drinking in alcohol-preferring rats; while memantine had a preferential effect on alcohol over saccharin, ketamine reduced responding for both solutions. Neither antagonist induced malaise, as shown by the lack of effect on water intake and motor activity. The mTOR inhibitor rapamycin blocked the effects of ketamine, but not those of memantine. Memantine and ketamine both reduce alcohol drinking in alcohol-preferring rats, but only memantine is selective for alcohol. The effects of ketamine, but not memantine, are mediated by mTOR. The results support the therapeutic potential of uncompetitive NMDA receptor antagonists, especially memantine, in alcohol addiction.
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Affiliation(s)
- Valentina Sabino
- Laboratory of Addictive Disorders (LAD), Department of Pharmacology and Experimental Therapeutics, Boston University School of Medicine, Boston, MA 02118, USA.
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Lockridge A, Romero G, Harrington J, Newland B, Gong Z, Cameron A, Yuan LL. Timing-dependent reduction in ethanol sedation and drinking preference by NMDA receptor co-agonist d-serine. Alcohol 2012; 46:389-400. [PMID: 22445805 DOI: 10.1016/j.alcohol.2011.11.004] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2011] [Revised: 10/31/2011] [Accepted: 11/09/2011] [Indexed: 01/06/2023]
Abstract
NMDA receptors become a major contributor to acute ethanol intoxication effects at high concentrations as ethanol binds to a unique site on the receptor and inhibits glutamatergic activity in multiple brain areas. Although a convincing body of literature exists on the ability of NMDA receptor antagonists to mimic and worsen cellular and behavioral ethanol effects, receptor agonists have been less well-studied. In addition to a primary agonist site for glutamate, the NMDA receptor contains a separate co-agonist site that responds to endogenous amino acids glycine and d-serine. d-serine is both selective for this co-agonist site and potent in boosting NMDA dependent activity even after systemic administration. In this study, we hypothesized that exogenous d-serine might ameliorate some acute ethanol behaviors by opposing NMDA receptor inhibition. We injected adult male C57 mice with a high concentration of d-serine at various time windows relative to ethanol administration and monitored sedation, motor coordination and voluntary ethanol drinking. d-serine (2.7 g/kg, ip) prolonged latency to a loss of righting reflex (LoRR) and shortened LoRR duration when given 15 min before ethanol (3 g/kg) but not when it was injected with or shortly after ethanol. Blood samples taken at sedative recovery and at fixed time intervals revealed no effect of d-serine on ethanol concentration but an ethanol-induced decrease in l-serine and glycine content was prevented by acute d-serine pre-administration. d-serine had no effect on ethanol-induced (2 g/kg) rotarod deficits in young adult animals but independently and interactively degraded motor performance in a subset of older mice. Finally, a week-long series of daily ip injections resulted in a 50% decrease in free choice ethanol preference for d-serine treated animals compared to saline-injected controls in a two-bottle choice experiment.
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Affiliation(s)
- Amber Lockridge
- Department of Neuroscience, University of Minnesota, Minneapolis, MN 55455, USA
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Karlsson RM, Adermark L, Molander A, Perreau-Lenz S, Singley E, Solomon M, Holmes A, Tanaka K, Lovinger DM, Spanagel R, Heilig M. Reduced alcohol intake and reward associated with impaired endocannabinoid signaling in mice with a deletion of the glutamate transporter GLAST. Neuropharmacology 2012; 63:181-9. [PMID: 22342743 DOI: 10.1016/j.neuropharm.2012.01.027] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2011] [Revised: 01/23/2012] [Accepted: 01/28/2012] [Indexed: 12/01/2022]
Abstract
A hyperglutamatergic state has been hypothesized to drive escalation of alcohol intake. This hypothesis predicts that an impairment of glutamate clearance through inactivation of the astrocytic glutamate transporter, GLAST (EAAT1), will result in escalation of alcohol consumption. Here, we used mice with a deletion of GLAST to test this prediction. WT and GLAST KO mice were tested for alcohol consumption using two-bottle free-choice drinking. Alcohol reward was evaluated using conditioned place preference (CPP). Sensitivity to depressant alcohol effects was tested using the accelerating rotarod, alcohol-induced hypothermia, and loss of righting reflex. Extracellular glutamate was measured using microdialysis, and striatal slice electrophysiology was carried out to examine plasticity of the cortico-striatal pathway as a model system in which adaptations to the constitutive GLAST deletion can be studied. Contrary to our hypothesis, GLAST KO mice showed markedly decreased alcohol consumption, and lacked CPP for alcohol, despite a higher locomotor response to this drug. Alcohol-induced ataxia, hypothermia, and sedation were unaffected. In striatal slices from GLAST KO mice, long-term depression (LTD) induced by high frequency stimulation, or by post-synaptic depolarization combined with the l-type calcium channel activator FPL 64176 was absent. In contrast, normal synaptic depression was observed after application of the cannabinoid 1 (CB1) receptor agonist WIN55,212-2. Constitutive deletion of GLAST unexpectedly results in markedly reduced alcohol consumption and preference, associated with markedly reduced alcohol reward. Endocannabinoid signaling appears to be down-regulated upstream of the CB1 receptor as a result of the GLAST deletion, and is a candidate mechanism behind the reduction of alcohol reward observed.
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Affiliation(s)
- Rose-Marie Karlsson
- Laboratory of Clinical and Translational Studies, National Institute on Alcoholism and Alcohol Abuse, NIH, 10 Center Drive, 1-5330, Bethesda, MD 20892-1108, USA
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Badanich KA, Doremus-Fitzwater TL, Mulholland PJ, Randall PK, Delpire E, Becker HC. NR2B-deficient mice are more sensitive to the locomotor stimulant and depressant effects of ethanol. GENES BRAIN AND BEHAVIOR 2011; 10:805-816. [PMID: 21762461 DOI: 10.1111/j.1601-183x.2011.00720.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
The NR2B subunit of N-methyl d-aspartate glutamate receptors influences pharmacological properties and confers greater sensitivity to the modulatory effects of ethanol. This study examined behavioral responses to acute ethanol in a conditional knockout mouse model that allowed for a delayed genetic deletion of the NR2B subunit to avoid mouse lethality. Mice lacking the NR2B gene (knockout) were produced by mating NR2B[f/f] mice with CAMKIIa-driven tTA transgenic mice and the tetO-CRE transgenic mice. Adult male and female offspring representing each of the resultant genotypes (knockout, CAM, CRE and wildtype mice) were tested for open-field locomotor activity following acute low- and high-dose ethanol challenge as well as loss of righting reflex. Findings indicate that male and female mice lacking the NR2B subunit exhibited greater overall activity in comparison to other genotypes during the baseline locomotor activity test. NR2B knockout mice exhibited an exaggerated stimulant response to 1.5 g/kg (i.p.) and an exaggerated depressant response to 3.0 g/kg (i.p.) ethanol challenge. In addition, NR2B knockout mice slept longer following a high dose of ethanol (4.0 g/kg, i.p.). To evaluate pharmacokinetics, clearance rates of ethanol (1.5, 4.0 g/kg, i.p.) were measured and showed that female NR2B knockouts had a faster rate of metabolism only at the higher ethanol dose. Western blot analyses confirmed significant reduction in NR2B expression in the forebrain of knockout mice. Collectively, these data indicate that the NR2B subunit of the N-methyl d-aspartate glutamate receptor is involved in regulating low-dose stimulant effects of ethanol and the depressant/hypnotic effects of ethanol.
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Affiliation(s)
- Kimberly A Badanich
- Charleston Alcohol Research Center, Department of Psychiatry and Behavioral Sciences, Medical University of South Carolina, Charleston, SC 29425
| | - Tamara L Doremus-Fitzwater
- Charleston Alcohol Research Center, Department of Psychiatry and Behavioral Sciences, Medical University of South Carolina, Charleston, SC 29425
| | - Patrick J Mulholland
- Charleston Alcohol Research Center, Department of Psychiatry and Behavioral Sciences, Medical University of South Carolina, Charleston, SC 29425
| | - Patrick K Randall
- Charleston Alcohol Research Center, Department of Psychiatry and Behavioral Sciences, Medical University of South Carolina, Charleston, SC 29425
| | - Eric Delpire
- Department of Anesthesiology, Vanderbilt University School of Medicine, Nashville, TN 37232
| | - Howard C Becker
- Charleston Alcohol Research Center, Department of Psychiatry and Behavioral Sciences, Medical University of South Carolina, Charleston, SC 29425.,RHJ Department of Veterans Affairs Medical Center, Charleston, SC 29425
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Voorhees CM, Cunningham CL. Involvement of the orexin/hypocretin system in ethanol conditioned place preference. Psychopharmacology (Berl) 2011; 214:805-18. [PMID: 21107540 PMCID: PMC3063857 DOI: 10.1007/s00213-010-2082-6] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/06/2009] [Accepted: 10/30/2010] [Indexed: 12/20/2022]
Abstract
RATIONALE Recent studies suggest that orexin/hypocretin is involved in drug reward and drug-seeking behaviors, including ethanol self-administration. However, orexin's role in ethanol-induced seeking behaviors remains unclear. OBJECTIVE These studies examined the role of orexin in the acquisition and expression of ethanol conditioned place preference (CPP) using the orexin 1 receptor (OX1R) antagonist SB-334867. METHODS Effects of SB-334867 (0-30 mg/kg) on locomotor activity were determined in DBA/2J mice (Experiment 1). SB-334867 (0-30 mg/kg) was administered during acquisition of ethanol (2 g/kg) CPP to determine whether orexin signaling is required (Experiment 2). Blood ethanol concentrations (BECs) were measured after ethanol (2 g/kg) injection to determine whether SB-334867 (30 mg/kg) pretreatment altered ethanol pharmacokinetics (Experiment 3). Finally, SB-334867 (0-40 mg/kg) was given before ethanol-free preference testing (Experiments 4 and 5). RESULTS SB-334867 did not alter basal locomotor activity (Experiment 1). SB-334867 (30 mg/kg) reduced ethanol-induced locomotor stimulation, but did not affect the acquisition of ethanol CPP (Experiment 2) or BEC, suggesting no alteration in ethanol pharmacokinetics (Experiment 3). Although OX1R antagonism blocked expression of a weak ethanol CPP (Experiment 4), it did not affect expression of a moderate to strong CPP (Experiment 5). CONCLUSIONS Blockade of OX1R by systemic administration of SB-334867 reduced ethanol-stimulated activity, but did not affect acquisition or expression of ethanol-induced CPP, suggesting that orexin does not influence ethanol's primary or conditioned rewarding effects. Other neurotransmitter systems may be sufficient to support acquisition and expression of CPP despite alterations in orexin signaling.
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Affiliation(s)
- Charlene M. Voorhees
- Department of Behavioral Neuroscience, L470 Portland Alcohol Research Center, Oregon Health and Science University, 3181 SW Sam Jackson Park Road, Portland, OR 97239-3098, USA
| | - Christopher L. Cunningham
- Department of Behavioral Neuroscience, L470 Portland Alcohol Research Center, Oregon Health and Science University, 3181 SW Sam Jackson Park Road, Portland, OR 97239-3098, USA
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Inhibition of extracellular signal-regulated kinase (ERK) activity with SL327 does not prevent acquisition, expression, and extinction of ethanol-seeking behavior in mice. Behav Brain Res 2010; 217:399-407. [PMID: 21074569 DOI: 10.1016/j.bbr.2010.11.018] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2010] [Revised: 11/03/2010] [Accepted: 11/04/2010] [Indexed: 11/24/2022]
Abstract
Although extracellular signal-regulated kinase (ERK) activity is essential for the acquisition of a variety of associative learning tasks, its involvement in the acquisition and extinction of ethanol (EtOH)-induced conditioned place preference (CPP) remains unknown. Therefore, in these experiments we examined the effects of the ERK-kinase (MEK)-inhibitor SL327 on acquisition and expression of EtOH-CPP as well as the dose- and time-dependent effects of SL327 on CPP extinction. The parametric findings of Experiment 1 showed that three 30-min (but not 15- or 5-min) non-reinforced trials were required to completely extinguish EtOH-CPP in male, DBA/2J mice. In Experiments 2 and 3, SL327 (30 and 50mg/kg), administered 30 or 90min prior to extinction trials, was unable to impair EtOH-CPP extinction. Experiment 4 showed that SL327 (50mg/kg) had no effect on acquisition of EtOH-CPP or the development of EtOH-induced sensitization during conditioning. When administered prior to testing in Experiments 5 and 6, SL327 did not alter expression of EtOH-CPP but did reduce test activity. Importantly, SL327 significantly reduced pERK protein levels when assessed in the dorsal striatum and motor cortex (Experiment 7). Together, these data suggest that EtOH-related learning and EtOH reward in mice, as assessed with CPP, are not impaired by the systemically administered MEK-inhibitor SL327.
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Gremel CM, Cunningham CL. Effects of disconnection of amygdala dopamine and nucleus accumbens N-methyl-d-aspartate receptors on ethanol-seeking behavior in mice. Eur J Neurosci 2009; 31:148-55. [PMID: 20092560 DOI: 10.1111/j.1460-9568.2009.07044.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
There is a strong interest in harnessing the genetic manipulations that are possible in mice to investigate the functional neural mechanisms modulating the associative processes that control drug-seeking behavior. However, it is unknown whether intracranial techniques, such as the disconnection procedure commonly used in rats to examine serial connectivity between implicated areas, can be successfully applied to mice. We have previously demonstrated that the expression of ethanol-seeking behavior in mice is dependent upon amygdala (Amy) dopamine and nucleus accumbens (Acb) N-methyl-d-aspartate (NMDA) receptor activation (Gremel & Cunningham, 2009). Here, we used a neuropharmacological disconnection procedure to investigate whether dopamine activation of the Amy directly leading to increases in Acb glutamate release and binding of NMDA receptors modulates the expression of ethanol-seeking behavior. Immediately before testing the expression of an ethanol-induced conditioned place preference, mice were given an Amy infusion of flupenthixol and either an ipsilateral or contralateral Acb infusion of AP-5. Although both ipsilateral and contralateral manipulations reduced the expression of ethanol conditioned place preference, in a separate experiment we demonstrated that a unilateral Acb infusion of AP-5, but not Amy flupenthixol, is sufficient to disrupt preference. The finding of a significant blockade by unilateral AP-5 into the Acb precludes any conclusions about a unique role for the Amy/Acb neuroanatomical connection in this model of ethanol-seeking behavior. Further, the current results suggest potential limitations in transferring techniques from rats to mice in order to study serial interactions between neural areas underlying motivated behaviors. Nevertheless, these findings provide evidence showing that Acb NMDA receptors play an important role in the expression of ethanol-conditioned behavior.
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Affiliation(s)
- Christina M Gremel
- Department of Behavioral Neuroscience and Portland Alcohol Research Center, Oregon Health & Science University, Portland, OR, USA
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Pautassi RM, Nizhnikov ME, Spear NE. Assessing appetitive, aversive, and negative ethanol-mediated reinforcement through an immature rat model. Neurosci Biobehav Rev 2009; 33:953-74. [PMID: 19428502 PMCID: PMC2693872 DOI: 10.1016/j.neubiorev.2009.03.008] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2008] [Revised: 03/13/2009] [Accepted: 03/13/2009] [Indexed: 11/25/2022]
Abstract
The motivational effects of drugs play a key role during the transition from casual use to abuse and dependence. Ethanol reinforcement has been successfully studied through Pavlovian and operant conditioning in adult rats and mice genetically selected for their ready acceptance of ethanol. Another model for studying ethanol reinforcement is the immature (preweanling) rat, which consumes ethanol and exhibits the capacity to process tactile, odor and taste cues and transfer information between different sensorial modalities. This review describes the motivational effects of ethanol in preweanling, heterogeneous non-selected rats. Preweanlings exhibit ethanol-mediated conditioned taste avoidance and conditioned place aversion. Ethanol's appetitive effects, however, are evident when using first- and second-order conditioning and operant procedures. Ethanol also devalues the motivational representation of aversive stimuli, suggesting early negative reinforcement. It seems that preweanlings are highly sensitive not only to the aversive motivational effects of ethanol but also to its positive and negative (anti-anxiety) reinforcement potential. The review underscores the advantages of using a developing rat to evaluate alcohol's motivational effects.
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Affiliation(s)
- Ricardo M Pautassi
- Center for Development and Behavioral Neuroscience, State University of New York at Binghamton, Binghamton, NY 13902-6000, USA.
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Chen YC, Holmes A. Effects of topiramate and other anti-glutamatergic drugs on the acute intoxicating actions of ethanol in mice: modulation by genetic strain and stress. Neuropsychopharmacology 2009; 34:1454-66. [PMID: 18843265 PMCID: PMC2669690 DOI: 10.1038/npp.2008.182] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Compounds with anti-glutamatergic properties currently in clinical use for various indications (eg Alzheimer's disease, epilepsy, psychosis, mood disorders) have potential utility as novel treatments for alcoholism. Enhanced sensitivity to certain acute intoxicating effects (ataxia, sedative) of alcohol may be one mechanism by which anti-glutamatergic drugs modulate alcohol use. We examined the effects of six compounds (memantine, dextromethorphan, haloperidol, lamotrigine, oxcarbazepine, and topiramate) on sensitivity to acute intoxicating effects of ethanol (ataxia, hypothermia, sedation/hypnosis) in C57BL/6J mice. Analysis of topiramate was extended to determine the influence of genetic background (by comparison of the 129S1, BALB/cJ, C57BL/6J, DBA/2J inbred strains) and prior stress history (by chronic exposure of C57BL/6J to swim stress) on topiramate's effects on ethanol-induced sedation/hypnosis. Results showed that one N-methyl-D-aspartate receptor (NMDAR) antagonist, memantine, but not another, dextromethorphan, potentiated the ataxic but not hypothermic or sedative/hypnotic effects of ethanol. Haloperidol increased ethanol-induced ataxia and sedation/hypnosis to a similar extent as the prototypical NMDAR antagonist MK-801. Of the anticonvulsants tested, lamotrigine accentuated ethanol-induced sedation/hypnosis, whereas oxcarbazepine was without effect. Topiramate was without effect per se under baseline conditions in C57BL/6J, but had a synergistic effect with MK-801 on ethanol-induced sedation/hypnosis. Comparing inbred strains, topiramate was found to significantly potentiate ethanol's sedative/hypnotic effects in BALB/cJ, but not 129S1, C57BL/6J, or DBA/2J strains. Topiramate also increased ethanol-induced sedation/hypnosis in C57BL/6J after exposure to chronic stress exposure. Current data demonstrate that with the exception of MK-801 and haloperidol, the compounds tested had either no significant or assay-selective effects on sensitivity to acute ethanol under baseline conditions in C57BL/6J. However, significant effects of topiramate were revealed as a function of co-treatment with an NMDAR blocker, genetic background, or prior stress history. These findings raise the possibility that topiramate and possibly other anti-glutamatergic drugs could promote the acute intoxicating effects of ethanol in specific subpopulations defined by genetics or life history.
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Affiliation(s)
- Yi-Chyan Chen
- Department of Psychiatry, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan
| | - Andrew Holmes
- Section on Behavioral Science and Genetics, Laboratory for Integrative Neuroscience, National Institute on Alcoholism and Alcohol Abuse, NIH, Rockville, MD, USA
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Abstract
Although progress has been made identifying neural mechanisms underlying ethanol's primary reinforcing effects, few studies have examined the mechanisms mediating ethanol-induced conditioned effects. A recent lesion study suggests that expression of ethanol-conditioned behaviors depends upon an intact amygdala and nucleus accumbens core. However, specific mechanisms within these nuclei are unknown. In the present experiments, we used site-specific microinfusions of dopamine and NMDA receptor antagonists to examine the roles of accumbens and amygdala in the expression of ethanol conditioned place preference (CPP) in mice. In experiments 1 and 2, a D1/D2/D3 receptor antagonist (flupenthixol) was infused into accumbens or amygdala before testing, whereas experiment 3 used pretest infusions of an NMDA antagonist (AP-5) to examine the role of intra-accumbens NMDA receptors. Dopamine antagonism of accumbens was without effect, but intra-amygdala infusions of flupenthixol blocked CPP expression. Moreover, this effect was dependent upon dopamine antagonism within the basolateral nucleus but not the central nucleus of the amygdala. Antagonism of NMDA receptors in accumbens also blocked CPP expression. The present findings suggest that expression of the ethanol-conditioned response depends upon amygdala dopamine and accumbens NMDA receptors. These are the first studies in any species to show a role for amygdala dopamine receptors and the first studies in mice to implicate accumbens NMDA receptors in ethanol-induced conditioned effects.
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Palachick B, Chen YC, Enoch AJ, Karlsson RM, Mishina M, Holmes A. Role of major NMDA or AMPA receptor subunits in MK-801 potentiation of ethanol intoxication. Alcohol Clin Exp Res 2008; 32:1479-92. [PMID: 18565157 DOI: 10.1111/j.1530-0277.2008.00715.x] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
BACKGROUND The glutamate system plays a major role in mediating EtOH's effects on brain and behavior, and is implicated in the pathophysiology of alcohol-related disorders. N-methyl-D-aspartate receptor (NMDAR) antagonists such as MK-801 (dizocilpine) interact with EtOH at the behavioral level, but the molecular basis of this interaction is unclear. METHODS We first characterized the effects of MK-801 treatment on responses to the ataxic (accelerating rotarod), hypothermic and sedative/hypnotic effects of acute EtOH administration in C57BL/6J and 129/SvImJ inbred mice. Effects of another NMDAR antagonist, phencyclidine, on EtOH-induced sedation/hypnosis were also assessed. Gene knockout of the NMDAR subunit NR2A or l-alpha-amino-3-hydroxy-5-methylisoxazole-4-propionate GluR1 or pharmacological antagonism of the NMDAR subunit NR2B (via Ro 25-6981) was employed to examine whether inactivating any one of these glutamate signaling molecules modified MK-801's effect on EtOH-related behaviors. RESULTS MK-801 markedly potentiated the ataxic effects of 1.75 g/kg EtOH and the sedative/hypnotic effects of 3.0 g/kg EtOH, but not the hypothermic effects of 3.0 g/kg EtOH, in C57BL/6J and 129/SvImJ mice. Phencyclidine potentiated EtOH-induced sedation/hypnosis in both inbred strains. Neither NR2A nor GluR1 KO significantly altered basal EtOH-induced ataxia, hypothermia, or sedation/hypnosis. Ro 25-6981 modestly increased EtOH-induced sedation/hypnosis. The ability of MK-801 to potentiate EtOH-induced ataxia and sedation/hypnosis was unaffected by GluR1 KO or NR2B antagonism. NR2A KO partially reduced MK-801 + EtOH-induced sedation/hypnosis, but not ataxia or hypothermia. CONCLUSIONS Data confirm a robust and response-specific potentiating effect of MK-801 on sensitivity to EtOH's intoxicating effects. Inactivation of three major components of glutamate signaling had no or only partial impact on the ability of MK-801 to potentiate behavioral sensitivity to EtOH. Further work to elucidate the mechanisms underlying NMDAR x EtOH interactions could ultimately provide novel insight into the role of NMDARs in alcoholism and its treatment.
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Affiliation(s)
- Benjamin Palachick
- Section on Behavioral Science and Genetics, Laboratory for Integrative Neuroscience, National Institute on Alcohol Abuse and Alcoholism, 5625 Fishers Lane Room 2N09, Rockville, MD 20852-9411, USA
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Szumlinski KK, Ary AW, Lominac KD, Klugmann M, Kippin TE. Accumbens Homer2 overexpression facilitates alcohol-induced neuroplasticity in C57BL/6J mice. Neuropsychopharmacology 2008; 33:1365-78. [PMID: 17568396 PMCID: PMC5099135 DOI: 10.1038/sj.npp.1301473] [Citation(s) in RCA: 92] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Homer proteins are integral components of the postsynaptic density that are necessary for alcohol-induced neuroplasticity within the nucleus accumbens (NAC). In this report, we describe the effects of chronic alcohol consumption upon NAC Homer expression and investigate the functional consequences of mimicking the alcohol-induced changes in Homer expression vis-à-vis alcohol-induced changes in NAC neurochemistry and behavior. Chronic alcohol consumption under continuous access (3 months; daily intake approximately 11.2+/-1.5 g/kg/day) produced a robust increase in NAC Homer2 protein levels that was apparent at 2 days, 2 weeks, and 2 months following withdrawal from alcohol drinking. The increased Homer2 expression was accompanied by a less enduring elevation in total mGluR1 and NR2b levels that were evident at 2 days and 2 weeks but not at the 2-month time point. Mimicking the alcohol-induced increase in Homer2 levels by viral transfection of NAC neurons in alcohol-preferring C57BL/6J inbred mice enhanced behavioral output for alcohol reinforcement and increased alcohol intake under both preprandial and postprandial conditions. Moreover, NAC Homer2 overexpression facilitated the expression of an alcohol-conditioned place preference, as well as the development of motor tolerance. Finally, NAC Homer2 overexpression facilitated NAC glutamate and dopamine release following an acute alcohol injection and augmented alcohol-induced dopamine and glutamate sensitization, but did not affect NAC gamma-aminobutyric acid levels. Thus, an upregulation in NAC mGluR-Homer2-N-methyl-D-aspartic acid receptor signaling appears to be an important molecular adaptation to alcohol that promotes neuroplasticity facilitating motivational drive for alcohol and the development of alcoholism-related behaviors.
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Affiliation(s)
- Karen K Szumlinski
- Department of Psychology, Neuroscience Research Institute, University of California at Santa Barbara, Santa Barbara, CA 93106-9660, USA.
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Szumlinski KK, Ary AW, Lominac KD. Homers regulate drug-induced neuroplasticity: implications for addiction. Biochem Pharmacol 2008; 75:112-33. [PMID: 17765204 PMCID: PMC2204062 DOI: 10.1016/j.bcp.2007.07.031] [Citation(s) in RCA: 103] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2007] [Revised: 07/22/2007] [Accepted: 07/23/2007] [Indexed: 12/20/2022]
Abstract
Drug addiction is a chronic, relapsing disorder, characterized by an uncontrollable motivation to seek and use drugs. Converging clinical and preclinical observations implicate pathologies within the corticolimbic glutamate system in the genetic predisposition to, and the development of, an addicted phenotype. Such observations pose cellular factors regulating glutamate transmission as likely molecular candidates in the etiology of addiction. Members of the Homer family of proteins regulate signal transduction through, and the trafficking of, glutamate receptors, as well as maintain and regulate extracellular glutamate levels in corticolimbic brain regions. This review summarizes the existing data implicating the Homer family of protein in acute behavioral and neurochemical sensitivity to drugs of abuse, the development of drug-induced neuroplasticity, as well as other behavioral and cognitive pathologies associated with an addicted state.
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Affiliation(s)
- Karen K Szumlinski
- Behavioral and Neural Genetics Laboratory, Department of Psychology and the Neuroscience Research Institute, University of California at Santa Barbara, Santa Barbara, CA 93106-9660, USA.
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Gass JT, Olive MF. Glutamatergic substrates of drug addiction and alcoholism. Biochem Pharmacol 2008; 75:218-65. [PMID: 17706608 PMCID: PMC2239014 DOI: 10.1016/j.bcp.2007.06.039] [Citation(s) in RCA: 355] [Impact Index Per Article: 22.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2007] [Revised: 06/22/2007] [Accepted: 06/26/2007] [Indexed: 12/20/2022]
Abstract
The past two decades have witnessed a dramatic accumulation of evidence indicating that the excitatory amino acid glutamate plays an important role in drug addiction and alcoholism. The purpose of this review is to summarize findings on glutamatergic substrates of addiction, surveying data from both human and animal studies. The effects of various drugs of abuse on glutamatergic neurotransmission are discussed, as are the effects of pharmacological or genetic manipulation of various components of glutamate transmission on drug reinforcement, conditioned reward, extinction, and relapse-like behavior. In addition, glutamatergic agents that are currently in use or are undergoing testing in clinical trials for the treatment of addiction are discussed, including acamprosate, N-acetylcysteine, modafinil, topiramate, lamotrigine, gabapentin and memantine. All drugs of abuse appear to modulate glutamatergic transmission, albeit by different mechanisms, and this modulation of glutamate transmission is believed to result in long-lasting neuroplastic changes in the brain that may contribute to the perseveration of drug-seeking behavior and drug-associated memories. In general, attenuation of glutamatergic transmission reduces drug reward, reinforcement, and relapse-like behavior. On the other hand, potentiation of glutamatergic transmission appears to facilitate the extinction of drug-seeking behavior. However, attempts at identifying genetic polymorphisms in components of glutamate transmission in humans have yielded only a limited number of candidate genes that may serve as risk factors for the development of addiction. Nonetheless, manipulation of glutamatergic neurotransmission appears to be a promising avenue of research in developing improved therapeutic agents for the treatment of drug addiction and alcoholism.
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Affiliation(s)
- Justin T Gass
- Center for Drug and Alcohol Programs, Department of Psychiatry and Behavioral Sciences, Medical University of South Carolina, Charleston, SC 29425, USA
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Tzschentke TM. Measuring reward with the conditioned place preference (CPP) paradigm: update of the last decade. Addict Biol 2007; 12:227-462. [PMID: 17678505 DOI: 10.1111/j.1369-1600.2007.00070.x] [Citation(s) in RCA: 1004] [Impact Index Per Article: 59.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Conditioned place preference (CPP) continues to be one of the most popular models to study the motivational effects of drugs and non-drug treatments in experimental animals. This is obvious from a steady year-to-year increase in the number of publications reporting the use this model. Since the compilation of the preceding review in 1998, more than 1000 new studies using place conditioning have been published, and the aim of the present review is to provide an overview of these recent publications. There are a number of trends and developments that are obvious in the literature of the last decade. First, as more and more knockout and transgenic animals become available, place conditioning is increasingly used to assess the motivational effects of drugs or non-drug rewards in genetically modified animals. Second, there is a still small but growing literature on the use of place conditioning to study the motivational aspects of pain, a field of pre-clinical research that has so far received little attention, because of the lack of appropriate animal models. Third, place conditioning continues to be widely used to study tolerance and sensitization to the rewarding effects of drugs induced by pre-treatment regimens. Fourth, extinction/reinstatement procedures in place conditioning are becoming increasingly popular. This interesting approach is thought to model certain aspects of relapse to addictive behavior and has previously almost exclusively been studied in drug self-administration paradigms. It has now also become established in the place conditioning literature and provides an additional and technically easy approach to this important phenomenon. The enormous number of studies to be covered in this review prevented in-depth discussion of many methodological, pharmacological or neurobiological aspects; to a large extent, the presentation of data had to be limited to a short and condensed summary of the most relevant findings.
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Affiliation(s)
- Thomas M Tzschentke
- Grünenthal GmbH, Preclinical Research and Development, Department of Pharmacology, Aachen, Germany.
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Cunningham CL, Gremel CM. Proximal ethanol pretreatment interferes with acquisition of ethanol-induced conditioned place preference. Pharmacol Biochem Behav 2006; 85:612-9. [PMID: 17141849 PMCID: PMC1797418 DOI: 10.1016/j.pbb.2006.10.016] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/19/2006] [Revised: 10/21/2006] [Accepted: 10/25/2006] [Indexed: 10/23/2022]
Abstract
Neurobiological mechanisms underlying rewarding and aversive effects of drugs are often studied by examining effects of various pretreatments on acquisition of conditioned place preference (CPP) or conditioned place aversion (CPA). However, few studies have looked at effects of pretreatment with the same drug used during conditioning. Such studies might offer insight into agonist actions on conditioning while also mimicking real world contingencies experienced by drug users. Previous work from our laboratory, which showed that same drug pre-exposure interfered with acquisition of ethanol CPA but not CPP, was limited by the use of only one pre-treatment time interval (65 min). Thus, the present studies were designed to study other intervals (-5, -15, -30). Pretreatment of DBA/2J mice with ethanol (2 g/kg) reduced the activity response normally evoked by the conditioning dose (2 g/kg) at all pretreatment times, but acquisition of CPP was disrupted only by pretreatment at -5 min. The overall pattern of findings suggests that ethanol's early pharmacological effects interfered with learning the association between the conditioned stimulus (CS) and ethanol 5 min later. Thus, one would expect ethanol agonists, when administered in close proximity to CS-ethanol pairings, to interfere with control of ethanol seeking by that CS.
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Affiliation(s)
- Christopher L Cunningham
- Department of Behavioral Neuroscience and Portland Alcohol Research Center, Oregon Health and Science University, Portland, OR 97239-3098, USA.
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Gremel CM, Gabriel KI, Cunningham CL. Topiramate does not affect the acquisition or expression of ethanol conditioned place preference in DBA/2J or C57BL/6J mice. Alcohol Clin Exp Res 2006; 30:783-90. [PMID: 16634846 DOI: 10.1111/j.1530-0277.2006.00091.x] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
BACKGROUND Topiramate, an anticonvulsant, has been reported to increase the number of abstinent days and decrease craving in alcohol-dependent individuals. However, the neurobiological basis for topiramate's effect is unknown. To assess topiramate's effect on ethanol's rewarding and conditioning rewarding effects, the present experiments examined the effects of topiramate on the acquisition and expression of ethanol-induced conditioned place preference (CPP) in DBA/2J and C57BL/6J mice. METHODS A biased apparatus and subject assignment were used. Mice received ethanol (2 g/kg) or saline paired with an initially nonpreferred floor (CS+) and saline paired with an initially preferred floor (CS-) for 5-minute conditioning trials. During the acquisition experiments, mice received a pretreatment of topiramate (0, 5, 10, 20, 50, or 100 mg/kg) 1 hour before the CS+ trials. On intervening CS- trials, mice received a pretreatment of saline. For the preference test, all mice received saline injections and were placed on a split floor for a 30-minute test. During the expression experiments, mice received no drug pretreatment on conditioning trials, but were pretreated with topiramate (0, 10, 50, or 100 mg/kg) 1 hour before the test session. RESULTS Ethanol-induced CPP was observed in both strains, but topiramate did not affect the acquisition or expression of ethanol-induced CPP in either strain. Despite its failure to alter CPP, topiramate produced dose-dependent locomotor activating effects in both strains. These effects were observed both in the presence and in the absence of ethanol. CONCLUSIONS These findings indicate that topiramate has no effect on ethanol's rewarding or conditioned rewarding effects as indexed by the place conditioning procedure. Thus, these studies raise the possibility that topiramate's efficacy in the treatment of alcoholism results from its impact on brain areas other than those that mediate ethanol's rewarding or conditioned rewarding effects. One alternative possibility is that topiramate decreases withdrawal-induced negative affective states that normally contribute to relapse.
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Affiliation(s)
- Christina M Gremel
- Department of Behavioral Neuroscience and the Portland Alcohol Research Center, Oregon Health & Science University, Portland 97239-3098, USA.
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Boyce-Rustay JM, Holmes A. Ethanol-related behaviors in mice lacking the NMDA receptor NR2A subunit. Psychopharmacology (Berl) 2006; 187:455-66. [PMID: 16835771 DOI: 10.1007/s00213-006-0448-6] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/15/2006] [Accepted: 05/23/2006] [Indexed: 11/24/2022]
Abstract
RATIONALE The ionotropic NMDA glutamate receptor is composed of NR1 and NR2 (NR2A-D) subunits. While there is compelling evidence that NMDA receptors modulate behavioral effects of ethanol, there is little understanding of how the subunit composition of the NMDA receptor mediates these effects. OBJECTIVES In the current study, we assessed the relative roles of NMDA subunits via phenotypic assessment of ethanol-related behaviors in NR2A knockout (KO) mice. RESULTS Results demonstrated that NR2A KO and heterozygous mice failed to show evidence of ethanol-induced conditioned place preference. As compared to wild-type (WT) controls, KO mice showed impaired motor coordination at baseline and, in some instances, following ethanol treatment on the accelerating rotarod, balance beam, and wire-hang tests. By contrast, open field locomotor-stimulant, sedative/hypnotic, and hypothermic responses to ethanol were not different between genotypes, nor was voluntary ethanol consumption and preference in a two-bottle choice paradigm. Blood ethanol concentrations were lower in KO than WT mice following intraperitoneal ethanol injection. CONCLUSIONS Results suggest that the loss of NR2A subunit-containing NMDA receptors impairs the ability to form or express learned reward-related responses to ethanol and causes deficits in motor coordination. However, the loss of NR2A does not alter other measures of acute ethanol intoxication or ethanol consumption, possibly implicating other NMDA subunits in these effects. These data provide novel insight into the role of NMDA receptors in modulating the behavioral effects of ethanol.
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Affiliation(s)
- Janel M Boyce-Rustay
- Section on Behavioral Science and Genetics, Laboratory for Integrative Neuroscience, National Institute on Alcohol Abuse and Alcoholism, Rockville, MD 20852, USA.
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Xiao ZM, Li LJ, Yu SZ, Lu ZN, Li CY, Zheng JQ. Effects of extracellular Ca(2+) influx and intracellular Ca(2+) release on ethanol-induced cytoplasmic Ca(2+) overload in cultured superior cervical ganglion neurons. Neurosci Lett 2005; 390:98-103. [PMID: 16115728 DOI: 10.1016/j.neulet.2005.08.004] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2005] [Revised: 07/19/2005] [Accepted: 08/01/2005] [Indexed: 10/25/2022]
Abstract
The present research was designed to investigate the interference of Ca(2+) homeostasis by ethanol on the primary cultured superior cervical ganglion (SCG) neurons. (1) Using the whole cell patch clamp recording, the amplitudes of voltage-dependent Ca(2+) channel (VDCC) currents could be reduced by ethanol in a concentration-dependent manner. Ethanol (100mM) inhibited about 25% of Ca(2+) channel current. However, the activation of Ca(2+) channel was not affected by ethanol at those concentrations. (2) The similar extent inhibitions of 100mM ethanol on the increments of intracellular Ca(2+) concentration ([Ca(2+)](i)) induced by 40 mM KCl and 1 microM A23187 were also observed in the fluo-3-AM loaded superior cervical ganglia (SCG) via detecting the change of [Ca(2+)](i) with a laser scanning confocal microscopy. In contrast, the basal [Ca(2+)](i) was significantly increased by ethanol alone in a concentration-dependent manner. These phenomena were also observed even under Ca(2+) free bath solution or the solution added 300 microM cadmium chloride conditions. Together with above results, our data suggest that ethanol increases basal [Ca(2+)](i), but it also inhibits the extracellular Ca(2+) influx through VDCC and ionophore channel. And the augment of basal [Ca(2+)](i) induced by ethanol might attribute to the Ca(2+) releasing from intracellular Ca(2+) pools.
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Affiliation(s)
- Zhe-Man Xiao
- Department of Neurology, Institution of Neuropsychiatry Research, Renmin Hospital of Wuhan University, Wuhan 430060, Hubei, PR China.
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Boyce-Rustay JM, Holmes A. Functional roles of NMDA receptor NR2A and NR2B subunits in the acute intoxicating effects of ethanol in mice. Synapse 2005; 56:222-5. [PMID: 15803501 DOI: 10.1002/syn.20143] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The present study examined the roles of NR2A and NR2B subunit-containing NMDA receptors in the mediation of the sedative/hypnotic effects of ethanol in mice. The ability of the competitive NMDA antagonist, CGP-37849 (0, 1, or 3 mg/kg), and the NR2B-selective antagonist, Ro 25-6981 (0, 3, or 10 mg/kg), to alter (3 g/kg) ethanol-induced sleep time was measured in C57BL/6J mice and NR2A knockout (KO) mice. The results show that pretreatment with either antagonist significantly potentiated the sedative/hypnotic effects of ethanol in C57BL/6J mice. These effects were not significantly altered in NR2A KO mice. Basal sleep time responses to ethanol were also normal in NR2A KO mice. These findings confirm a major role for NMDA receptors in the acute intoxicating actions of ethanol and provide tentative support for a prepotent role of the NR2B subunit in these effects.
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Affiliation(s)
- Janel M Boyce-Rustay
- Section on Behavioral Science and Genetics, Laboratory for Integrative Neuroscience, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, MD 20892, USA.
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