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Szulc M, Kujawski R, Pacholak A, Poprawska M, Czora-Poczwardowska K, Geppert B, Mikołajczak PŁ. Cannabidiol as a Modulator of the Development of Alcohol Tolerance in Rats. Nutrients 2023; 15:nu15071702. [PMID: 37049542 PMCID: PMC10097131 DOI: 10.3390/nu15071702] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2023] [Revised: 03/27/2023] [Accepted: 03/29/2023] [Indexed: 04/03/2023] Open
Abstract
The study aimed to explore in vivo the influence of cannabidiol (CBD) on the development of alcohol tolerance in rats. Rats were treated with ethanol (3.0 g/kg, i.p.) and CBD (20 mg/kg, p.o.) for nine successive days, and rectal body temperature, sedation (sleeping time), and blood alcohol concentration (BAC) were measured. In the prefrontal cortex, hippocampus, and striatum, the cannabinoid (CB1R and CB2R) and dopaminergic (DRD1, DRD2, DRD4, DRD5) receptors’ mRNA level changes were analyzed using the quantitative RT-PCR method. CBD inhibited the development of tolerance to the hypothermic and sedative action of alcohol, coupled with BAC elevation. On a molecular level, the most pronounced effects of the CBD + ethanol interaction in the striatum were observed, where CBD reversed the downregulation of CB2R gene transcription caused by ethanol. For CB1R, DRD1, and DRD2 mRNAs, the CBD + ethanol interaction produced opposite effects than for CB2R ones. In turn, for the transcription of genes encoding dopaminergic receptors, the most potent effect of alcohol as CBD occurred in the hippocampus. However, the combined CBD and alcohol administration showed the same effect for each substance administered separately. Since tolerance is considered a prelude to drug addiction, obtained results allow us to emphasize the thesis that CBD can inhibit the development of alcohol dependence in rats.
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Affiliation(s)
- Michał Szulc
- Department of Pharmacology, Poznan University of Medical Sciences, Rokietnicka 3, 60-806 Poznan, Poland
| | - Radosław Kujawski
- Department of Pharmacology, Poznan University of Medical Sciences, Rokietnicka 3, 60-806 Poznan, Poland
| | - Amanda Pacholak
- Institute of Chemical Technology and Engineering, Poznan University of Technology, Berdychowo 4, 60-965 Poznan, Poland
| | - Marta Poprawska
- Department of Pharmacology, Poznan University of Medical Sciences, Rokietnicka 3, 60-806 Poznan, Poland
| | | | - Bogna Geppert
- Department of Forensic Medicine, Collegium Medicum, University of Zielona Góra, Zyty 28, 65-046 Zielona Góra, Poland
| | - Przemysław Ł. Mikołajczak
- Department of Pharmacology, Poznan University of Medical Sciences, Rokietnicka 3, 60-806 Poznan, Poland
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Neasta J, Darcq E, Jeanblanc J, Carnicella S, Ben Hamida S. GPCR and Alcohol-Related Behaviors in Genetically Modified Mice. Neurotherapeutics 2020; 17:17-42. [PMID: 31919661 PMCID: PMC7007453 DOI: 10.1007/s13311-019-00828-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
G protein-coupled receptors (GPCRs) constitute the largest class of cell surface signaling receptors and regulate major neurobiological processes. Accordingly, GPCRs represent primary targets for the treatment of brain disorders. Several human genetic polymorphisms affecting GPCRs have been associated to different components of alcohol use disorder (AUD). Moreover, GPCRs have been reported to contribute to several features of alcohol-related behaviors in animal models. Besides traditional pharmacological tools, genetic-based approaches mostly aimed at deleting GPCR genes provided substantial information on how key GPCRs drive alcohol-related behaviors. In this review, we summarize the alcohol phenotypes that ensue from genetic manipulation, in particular gene deletion, of key GPCRs in rodents. We focused on GPCRs that belong to fundamental neuronal systems that have been shown as potential targets for the development of AUD treatment. Data are reviewed with particular emphasis on alcohol reward, seeking, and consumption which are behaviors that capture essential aspects of AUD. Literature survey indicates that in most cases, there is still a gap in defining the intracellular transducers and the functional crosstalk of GPCRs as well as the neuronal populations in which their signaling regulates alcohol actions. Further, the implication of only a few orphan GPCRs has been so far investigated in animal models. Combining advanced pharmacological technologies with more specific genetically modified animals and behavioral preclinical models is likely necessary to deepen our understanding in how GPCR signaling contributes to AUD and for drug discovery.
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Affiliation(s)
- Jérémie Neasta
- Laboratoire de Pharmacologie, Faculté de Pharmacie, University of Montpellier, 34093, Montpellier, France
| | - Emmanuel Darcq
- Douglas Hospital Research Center, Department of Psychiatry, McGill University, 6875 Boulevard LaSalle, Montreal, Quebec, H4H 1R3, Canada
| | - Jérôme Jeanblanc
- Research Group on Alcohol and Pharmacodependences-INSERM U1247, University of Picardie Jules Verne, 80025, Amiens, France
| | - Sebastien Carnicella
- INSERM U1216, Grenoble Institut des Neurosciences (GIN), University of Grenoble Alpes, 38000, Grenoble, France
| | - Sami Ben Hamida
- Douglas Hospital Research Center, Department of Psychiatry, McGill University, 6875 Boulevard LaSalle, Montreal, Quebec, H4H 1R3, Canada.
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Solinas M, Belujon P, Fernagut PO, Jaber M, Thiriet N. Dopamine and addiction: what have we learned from 40 years of research. J Neural Transm (Vienna) 2018; 126:481-516. [PMID: 30569209 DOI: 10.1007/s00702-018-1957-2] [Citation(s) in RCA: 74] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2018] [Accepted: 11/17/2018] [Indexed: 12/22/2022]
Abstract
Among the neurotransmitters involved in addiction, dopamine (DA) is clearly the best known. The critical role of DA in addiction is supported by converging evidence that has been accumulated in the last 40 years. In the present review, first we describe the dopaminergic system in terms of connectivity, functioning and involvement in reward processes. Second, we describe the functional, structural, and molecular changes induced by drugs within the DA system in terms of neuronal activity, synaptic plasticity and transcriptional and molecular adaptations. Third, we describe how genetic mouse models have helped characterizing the role of DA in addiction. Fourth, we describe the involvement of the DA system in the vulnerability to addiction and the interesting case of addiction DA replacement therapy in Parkinson's disease. Finally, we describe how the DA system has been targeted to treat patients suffering from addiction and the result obtained in clinical settings and we discuss how these different lines of evidence have been instrumental in shaping our understanding of the physiopathology of drug addiction.
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Affiliation(s)
- Marcello Solinas
- Université de Poitiers, INSERM, U-1084, Laboratoire de Neurosciences Expérimentales et Cliniques, Poitiers, France.
| | - Pauline Belujon
- Université de Poitiers, INSERM, U-1084, Laboratoire de Neurosciences Expérimentales et Cliniques, Poitiers, France
| | - Pierre Olivier Fernagut
- Université de Poitiers, INSERM, U-1084, Laboratoire de Neurosciences Expérimentales et Cliniques, Poitiers, France
| | - Mohamed Jaber
- Université de Poitiers, INSERM, U-1084, Laboratoire de Neurosciences Expérimentales et Cliniques, Poitiers, France
- CHU de Poitiers, Poitiers, France
| | - Nathalie Thiriet
- Université de Poitiers, INSERM, U-1084, Laboratoire de Neurosciences Expérimentales et Cliniques, Poitiers, France
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4
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Sokoloff P, Le Foll B. The dopamine D3 receptor, a quarter century later. Eur J Neurosci 2016; 45:2-19. [DOI: 10.1111/ejn.13390] [Citation(s) in RCA: 150] [Impact Index Per Article: 18.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2016] [Revised: 07/23/2016] [Accepted: 08/28/2016] [Indexed: 12/16/2022]
Affiliation(s)
| | - Bernard Le Foll
- Centre for Addiction and Mental Health; Toronto ON Canada
- University of Toronto; Toronto ON Canada
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Emotional regulatory function of receptor interacting protein 140 revealed in the ventromedial hypothalamus. Brain Behav Immun 2014; 40:226-34. [PMID: 24726835 PMCID: PMC4102625 DOI: 10.1016/j.bbi.2014.03.019] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/14/2014] [Revised: 03/13/2014] [Accepted: 03/28/2014] [Indexed: 12/16/2022] Open
Abstract
Receptor-interacting protein (RIP140) is a transcription co-regulator highly expressed in macrophages to regulate inflammatory and metabolic processes. However, its implication in neurological, cognitive and emotional conditions, and the cellular systems relevant to its biological activity within the central nervous system are currently less clear. A transgenic mouse line with macrophage-specific knockdown of RIP140 was generated (MΦRIPKD mice) and brain-region specific RIP140 knockdown efficiency evaluated. Mice were subjected to a battery of tests, designed to evaluate multiple behavioral domains at naïve or following site-specific RIP140 re-expression. Gene expression analysis assessed TNF-α, IL-1β, TGF-1β, IL1-RA and neuropeptide Y (NPY) expression, and in vitro studies examined the effects of macrophage's RIP140 on astrocytes' NPY production. We found that RIP140 expression was dramatically reduced in macrophages within the ventromedial hypothalamus (VMH) and the cingulate cortex of MΦRIPKD mice. These animals exhibited increased anxiety- and depressive-like behaviors. VMH-targeted RIP140 re-expression in MΦRIPKD mice reversed its depressive- but not its anxiety-like phenotype. Analysis of specific neurochemical changes revealed reduced astrocytic-NPY expression within the hypothalamus of MΦRIPKD mice, and in vitro analysis confirmed that conditioned medium of RIP140-silnenced macrophage culture could no longer stimulate NPY production from astrocytes. The current study revealed an emotional regulatory function of macrophage-derived RIP140 in the VMH, and secondary dysregulation of NPY within hypothalamic astrocyte population, which might be associated with the observed behavioral phenotype of MΦRIPKD mice. This study highlights RIP140 as a novel target for the development of potential therapeutic and intervention strategies for emotional regulation disorders.
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Dopamine D3 receptor is necessary for ethanol consumption: an approach with buspirone. Neuropsychopharmacology 2014; 39:2017-28. [PMID: 24584330 PMCID: PMC4059912 DOI: 10.1038/npp.2014.51] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/26/2013] [Revised: 02/12/2014] [Accepted: 02/24/2014] [Indexed: 11/09/2022]
Abstract
Mesolimbic dopamine (DA) controls drug- and alcohol-seeking behavior, but the role of specific DA receptor subtypes is unclear. We tested the hypothesis that D3R gene deletion or the D3R pharmacological blockade inhibits ethanol preference in mice. D3R-deficient mice (D3R(-/-)) and their wild-type (WT) littermates, treated or not with the D3R antagonists SB277011A and U99194A, were tested in a long-term free choice ethanol-drinking (two-bottle choice) and in a binge-like ethanol-drinking paradigm (drinking in the dark, DID). The selectivity of the D3R antagonists was further assessed by molecular modeling. Ethanol intake was negligible in D3R(-/-) and robust in WT both in the two-bottle choice and DID paradigms. Treatment with D3R antagonists inhibited ethanol intake in WT but was ineffective in D3R(-/-) mice. Ethanol intake increased the expression of RACK1 and brain-derived neurotrophic factor (BDNF) in both WT and D3R(-/-); in WT there was also a robust overexpression of D3R. Thus, increased expression of D3R associated with activation of RACK1/BDNF seems to operate as a reinforcing mechanism in voluntary ethanol intake. Indeed, blockade of the BDNF pathway by the TrkB selective antagonist ANA-12 reversed chronic stable ethanol intake and strongly decreased the striatal expression of D3R. Finally, we evaluated buspirone, an approved drug for anxiety disorders endowed with D3R antagonist activity (confirmed by molecular modeling analysis), that resulted effective in inhibiting ethanol intake. Thus, DA signaling via D3R is essential for ethanol-related reward and consumption and may represent a novel therapeutic target for weaning.
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Caine SB, Thomsen M, Barrett AC, Collins GT, Grundt P, Newman AH, Butler P, Xu M. Cocaine self-administration in dopamine D₃ receptor knockout mice. Exp Clin Psychopharmacol 2012; 20:352-63. [PMID: 22867038 PMCID: PMC3587777 DOI: 10.1037/a0029135] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The dopamine D₃ receptor has received attention over the last two decades as a target for medications development for substance abuse disorders. Results have remained mixed. Despite emergence of more D₃-selective ligands, possible attribution of observed effects to D₂ receptors remains a concern. Knockout mice may help shed light on mechanisms. Here we evaluated the effect of constitutive D₃ receptor inactivation ("knockout") on the reinforcing effects of cocaine. We tested D₃ wild-type (WT), heterozygous (D₃⁺/⁻), and knockout (D₃⁻/⁻), mice in acquisition and maintenance of intravenous self-administration across a broad range of cocaine doses, using a fixed ratio (FR) 1 and a progressive ratio (PR) schedule of reinforcement, along with parallel food-reinforced studies. Generally, D₃⁻/⁻ mice showed cocaine self-administration comparable to WT controls across assays. Moderate and nonsignificant trends toward lesser reinforcing effects of a low cocaine dose (0.32 mg/kg) were apparent in acquisition and PR studies, consistent with the idea that the D₃ receptor may play a subtle role in the reinforcing effects of low cocaine doses under low FR conditions. However, those effects with cocaine self-administration were more subtle than the lower responding of D₃ knockout mice observed with food-maintained behavior. In addition, the D₃ antagonist PG01037 failed to affect cocaine self-administration under an FR 1 schedule in WT mice. The present data do not support a necessary role for the D₃ receptor in the direct reinforcing effects of cocaine.
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Affiliation(s)
- S Barak Caine
- Alcohol and Drug Abuse Research Center, McLean Hospital/Harvard Medical School, MA 02478, USA.
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Flaisher-Grinberg S, Einat H. Strain-specific battery of tests for domains of mania: effects of valproate, lithium and imipramine. Front Psychiatry 2010; 1:10. [PMID: 21423422 PMCID: PMC3059633 DOI: 10.3389/fpsyt.2010.00010] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/04/2010] [Accepted: 03/29/2010] [Indexed: 01/11/2023] Open
Abstract
The lack of efficient animal models for bipolar disorder (BPD), especially for the manic pole, is a major factor hindering the research of its pathophysiology and the development of improved drug treatments. The present study was designed to identify an appropriate mouse strain for modeling some behavioral domains of mania and to evaluate the effects of drugs using this strain. The study compared the behavior of four strains: Black Swiss, C57Bl/6, CBA/J and A/J mice in a battery of tests that included spontaneous activity; sweet solution preference; light/dark box; resident-intruder; forced-swim and amphetamine-induced hyperactivity. Based on the 'manic-like' behavior demonstrated by the Black Swiss strain, the study evaluated the effects of the mood stabilizers valproate and lithium and of the antidepressant imipramine in the same tests using this strain. Results indicated that lithium and valproate attenuate the 'manic-like' behavior of Black Swiss mice whereas imipramine had no effects. These findings suggest that Black Swiss mice might be a good choice for modeling several domains of mania and distinguishing the effects of drugs on these specific domains. However, the relevance of the behavioral phenotype of Black Swiss mice to the biology of BPD is unknown at this time and future studies will investigate molecular differences between Black Swiss mice and other strains and asess the interaction between strain and mood stabilizing treatment.
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Ethanol-induced hyperactivity is associated with hypodopaminergia in the 22-TNJ ENU-mutated mouse. Alcohol 2009; 43:421-31. [PMID: 19801272 DOI: 10.1016/j.alcohol.2009.04.006] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2009] [Revised: 04/22/2009] [Accepted: 04/29/2009] [Indexed: 11/23/2022]
Abstract
Characterization of neurochemical and behavioral responses to ethanol in phenotypically distinct mouse strains can provide insight into the mechanisms of ethanol stimulant actions. Increases in striatal dopamine (DA) levels have often been linked to ethanol-induced hyperactivity. We examined the functional status of the DA system and behavioral responsiveness to ethanol, cocaine, and a DA-receptor agonist in an N-ethyl-N-nitrosourea-mutagenized mouse strain, 22-TNJ, generated by the Integrative Neuroscience Initiative on Alcoholism Consortium. The 22-TNJ mouse strain exhibited greater locomotor responses to 2.25g/kg ethanol and 10mg/kg cocaine, compared with control mice. In vivo microdialysis showed low-baseline DA levels and a larger DA increase with both 2.25g/kg ethanol and 10mg/kg cocaine. In in vitro voltammetry studies, the 22-TNJ mice displayed increased V(max) rates for DA uptake, possibly contributing to the low-baseline DA levels found with microdialysis. Finally, 22-TNJ mice showed enhanced in vitro autoreceptor sensitivity to the D2/D3 agonist, quinpirole, and greater locomotor responses to both autoreceptor-selective and postsynaptic receptor-selective doses of apomorphine compared with controls. Taken together, these results indicate that the dopaminergic system of the 22-TNJ mouse is low functioning compared with control, with consequent receptor supersensitivity, such that mutant animals exhibit enhanced behavioral responses to DA-activating drugs, such as ethanol. Thus, the 22-TNJ mouse represents a model for a relatively hypodopaminergic system, and could provide important insights into the mechanisms of hyper-responsiveness to ethanol's stimulant actions.
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Abstract
Drug dependence is a chronic, relapsing disorder in which compulsive drug-seeking and drug-taking behaviours persist despite serious negative consequences. Addictive substances, such as opioids, ethanol, psychostimulants and nicotine, induce pleasant states or relieve distress, effects that contribute to their recreational use. Dopamine is critically involved in drug addiction processes. However, the role of the various dopaminergic receptor subtypes has been difficult to delineate. Here, we will review the information collected implicating the receptors of the D1 family (DRD1 and DRD5) and of the D2 family (DRD2, DRD3 and DRD4) in drug addiction. We will summarize the distribution of these receptors in the brain, the preclinical experiments carried out with pharmacological and transgenic approaches and the genetic studies carried out linking genetic variants of these receptors to drug addiction phenotypes. A meta-analysis of the studies carried out evaluating DRD2 and alcohol dependence is also provided, which indicates a significant association. Overall, this review indicates that different aspects of the addiction phenotype are critically influenced by dopaminergic receptors and that variants of those genes seem to influence some addiction phenotypes in humans.
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11
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Kokavec A. Is decreased appetite for food a physiological consequence of alcohol consumption? Appetite 2008; 51:233-43. [DOI: 10.1016/j.appet.2008.03.011] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2007] [Revised: 03/02/2008] [Accepted: 03/26/2008] [Indexed: 10/22/2022]
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Abstract
Molecular techniques allowing in vivo modulation of gene expression have provided unique opportunities and challenges for behavioural studies aimed at understanding the function of particular genes or biological systems under physiological or pathological conditions. Although various animal models are available, the laboratory mouse (Mus musculus) has unique features and is therefore a preferred animal model. The mouse shares a remarkable genetic resemblance and aspects of behaviour with humans. In this review, first we describe common mouse models for behavioural analyses. As both genetic and environmental factors influence behavioural performance and need to be carefully evaluated in behavioural experiments, considerations for designing and interpretations of these experiments are subsequently discussed. Finally, common behavioural tests used to assess brain function are reviewed, and it is illustrated how behavioural tests are used to increase our understanding of the role of histaminergic neurotransmission in brain function.
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Affiliation(s)
- Peter van Meer
- *Department of Behavioral Neuroscience, Oregon Health & Science University, Portland, Oregon 97239, U.S.A
| | - Jacob Raber
- *Department of Behavioral Neuroscience, Oregon Health & Science University, Portland, Oregon 97239, U.S.A
- †Department of Neurology and Division of Neuroscience, ONPRC, Oregon Health & Science University, Portland, Oregon 97239, U.S.A
- To whom correspondence should be addressed (email )
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Pierce RC, Kumaresan V. The mesolimbic dopamine system: the final common pathway for the reinforcing effect of drugs of abuse? Neurosci Biobehav Rev 2005; 30:215-38. [PMID: 16099045 DOI: 10.1016/j.neubiorev.2005.04.016] [Citation(s) in RCA: 590] [Impact Index Per Article: 31.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2005] [Revised: 04/05/2005] [Accepted: 04/19/2005] [Indexed: 11/23/2022]
Abstract
In this review we will critically assess the hypothesis that the reinforcing effect of virtually all drugs of abuse is primarily dependent on activation of the mesolimbic dopamine system. The focus is on five classes of abused drugs: psychostimulants, opiates, ethanol, cannabinoids and nicotine. For each of these drug classes, the pharmacological and physiological mechanisms underlying the direct or indirect influence on mesolimbic dopamine transmission will be reviewed. Next, we evaluate behavioral pharmacological experiments that specifically assess the influence of activation of the mesolimbic dopamine system on drug reinforcement, with particular emphasis on animal experiments using drug self-administration paradigms. There is overwhelming evidence that all five classes of abused drugs increase dopamine transmission in limbic regions of the brain through interactions with a variety of transporters, ionotropic receptors and metabotropic receptors. Behavioral pharmacological experiments indicate that increased dopamine transmission is clearly both necessary and sufficient to promote psychostimulant reinforcement. For the other four classes of abused substances, self-administration experiments suggest that although increasing mesolimbic dopamine transmission plays an important role in the reinforcing effects of opiates, ethanol, cannabinoids and nicotine, there are also dopamine-independent processes that contribute significantly to the reinforcing effects of these compounds.
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Affiliation(s)
- R Christopher Pierce
- Department of Pharmacology, Boston University School of Medicine, 715 Albany Street, L603 Boston, MA 02118, USA.
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Rhodes JS, Best K, Belknap JK, Finn DA, Crabbe JC. Evaluation of a simple model of ethanol drinking to intoxication in C57BL/6J mice. Physiol Behav 2005; 84:53-63. [PMID: 15642607 DOI: 10.1016/j.physbeh.2004.10.007] [Citation(s) in RCA: 623] [Impact Index Per Article: 32.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2004] [Revised: 09/02/2004] [Accepted: 10/14/2004] [Indexed: 11/28/2022]
Abstract
Because of intrinsic differences between humans and mice, no single mouse model can represent all features of a complex human trait such as alcoholism. It is therefore necessary to develop partial models. One important feature is drinking to the point where blood ethanol concentration (BEC) reaches levels that have measurable affects on physiology and/or behavior (>1.0 mg ethanol/ml blood). Most models currently in use examine relative oral self-administration from a bottle containing alcohol versus one containing water (two-bottle preference drinking), or oral operant self-administration. In these procedures, it is not clear when or if the animals drink to pharmacologically significant levels because the drinking is episodic and often occurs over a 24-h period. The aim of this study was to identify the optimal parameters and evaluate the reliability of a very simple procedure, taking advantage of a mouse genotype (C57BL/6J) that is known to drink large quantities of ethanol. We exchanged for the water bottle a solution containing ethanol in tap water for a limited period, early in the dark cycle, in the home cage. Mice regularly drank sufficient ethanol to achieve BEC>1.0 mg ethanol/ml blood. The concentration of ethanol offered (10%, 20% or 30%) did not affect consumption in g ethanol/kg body weight. The highest average BEC ( approximately 1.6 mg/ml) occurred when the water-to-ethanol switch occurred 3 h into the dark cycle, and when the ethanol was offered for 4 rather than 2 h. Ethanol consumption was consistent within individual mice, and reliably predicted BEC after the period of ethanol access. C57BL/6J mice from three sources provided equivalent data, while DBA/2J mice drank much less than C57BL/6J in this test. We discuss advantages of the model for high-throughput screening assays where the goal is to find other genotypes of mice that drink excessively, or to screen drugs for their efficacy in blocking excessive drinking.
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Affiliation(s)
- Justin S Rhodes
- Portland Alcohol Research Center, Department of Behavioral Neuroscience, Oregon Health and Science University, and VA Medical Center, Portland, Oregon 97239, USA.
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Holmes A, Lachowicz JE, Sibley DR. Phenotypic analysis of dopamine receptor knockout mice; recent insights into the functional specificity of dopamine receptor subtypes. Neuropharmacology 2005; 47:1117-34. [PMID: 15567422 DOI: 10.1016/j.neuropharm.2004.07.034] [Citation(s) in RCA: 108] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2004] [Revised: 06/20/2004] [Accepted: 07/28/2004] [Indexed: 12/11/2022]
Abstract
The functional specificity of dopamine receptor subtypes remains incompletely understood, in part due to the absence of highly selective agonists and antagonists. Phenotypic analysis of dopamine receptor knockout mice has been instrumental in identifying the role of dopamine receptor subtypes in mediating dopamine's effects on motor function, cognition, reward, and emotional behaviors. In this article, we provide an update of recent studies in dopamine receptor knockout mice and discuss the limitations and future promise of this approach.
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Affiliation(s)
- Andrew Holmes
- Section on Behavioral Science and Genetics, National Institute of Alcoholism and Alcohol Abuse, National Institutes of Health, Bethesda, MD 20892, USA.
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Phillips TJ, Broadbent J, Burkhart-Kasch S, Henderson C, Wenger CD, McMullin C, McKinnon CS, Cunningham CL. Genetic Correlational Analyses of Ethanol Reward and Aversion Phenotypes in Short-Term Selected Mouse Lines Bred for Ethanol Drinking or Ethanol-Induced Conditioned Taste Aversion. Behav Neurosci 2005; 119:892-910. [PMID: 16187818 DOI: 10.1037/0735-7044.119.4.892] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Short-term selective breeding created mouse lines divergent for ethanol drinking (high drinking short-term selected line [STDRHI], low drinking [STDRLO]) or ethanol-induced conditioned taste aversion (CTA; high [HTA], low [LTA]). Compared with STDRLO, STDRHI mice consumed more saccharin and less quinine, exhibited greater ethanol-induced conditioned place preference (CPP), and showed reduced ethanol stimulation and sensitization under some conditions; a line difference in ethanol-induced CTA was not consistently found. Compared with LTA, HTA mice consumed less ethanol but were similar in saccharin consumption, sensitivity to ethanol-induced CPP, and ethanol-induced locomotor stimulation and sensitization. These data suggest that ethanol drinking is genetically associated with several reward-and aversion-related traits. The interpretation of ethanol-induced CTA as more genetically distinct must be tempered by the inability to test the CTA lines beyond Selection Generation 2.
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Affiliation(s)
- Tamara J Phillips
- Department of Behavioral Neuroscience and Portland Alcohol Research Center, Oregon Health & Science University, Portland, OR 97239, USA.
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17
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Spanagel R, Pendyala G, Abarca C, Zghoul T, Sanchis-Segura C, Magnone MC, Lascorz J, Depner M, Holzberg D, Soyka M, Schreiber S, Matsuda F, Lathrop M, Schumann G, Albrecht U. The clock gene Per2 influences the glutamatergic system and modulates alcohol consumption. Nat Med 2004; 11:35-42. [PMID: 15608650 DOI: 10.1038/nm1163] [Citation(s) in RCA: 425] [Impact Index Per Article: 21.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2004] [Accepted: 10/28/2004] [Indexed: 11/09/2022]
Abstract
Period (Per) genes are involved in regulation of the circadian clock and are thought to modulate several brain functions. We demonstrate that Per2(Brdm1) mutant mice, which have a deletion in the PAS domain of the Per2 protein, show alterations in the glutamatergic system. Lowered expression of the glutamate transporter Eaat1 is observed in these animals, leading to reduced uptake of glutamate by astrocytes. As a consequence, glutamate levels increase in the extracellular space of Per2(Brdm1) mutant mouse brains. This is accompanied by increased alcohol intake in these animals. In humans, variations of the PER2 gene are associated with regulation of alcohol consumption. Acamprosate, a drug used to prevent craving and relapse in alcoholic patients is thought to act by dampening a hyper-glutamatergic state. This drug reduced augmented glutamate levels and normalized increased alcohol consumption in Per2(Brdm1) mutant mice. Collectively, these data establish glutamate as a link between dysfunction of the circadian clock gene Per2 and enhanced alcohol intake.
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Affiliation(s)
- Rainer Spanagel
- Department of Psychopharmacology, Central Institute of Mental Health, J5, 68159 Mannheim, Germany.
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