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Hirasawa-Fujita M, Bly MJ, Ellingrod VL, Dalack GW, Domino EF. Genetic Variation of the Mu Opioid Receptor (OPRM1) and Dopamine D2 Receptor (DRD2) is Related to Smoking Differences in Patients with Schizophrenia but not Bipolar Disorder. ACTA ACUST UNITED AC 2014. [DOI: 10.3371/csrp.mhmb.061314] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Zhou Y, Kreek MJ. Alcohol: a stimulant activating brain stress responsive systems with persistent neuroadaptation. Neuropharmacology 2014; 87:51-8. [PMID: 24929109 DOI: 10.1016/j.neuropharm.2014.05.044] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2014] [Revised: 05/08/2014] [Accepted: 05/19/2014] [Indexed: 01/08/2023]
Abstract
Addictive diseases, including addiction to alcohol, opiates or cocaine, pose massive public health costs. Addictions are chronic relapsing brain diseases, caused by drug-induced direct effects and persistent neuroadaptations at the molecular, cellular and behavioral levels. These drug-type specific neuroadapations are mainly contributed by three factors: environment, including stress, the direct reinforcing effects of the drug on the CNS, and genetics. Results from animal models and basic clinical research (including human genetic study) have shown important interactions between the stress responsive systems and alcohol abuse. In this review we will discuss the involvement of the dysregulation of the stress responsive hypothalamic-pituitary-adrenal (HPA) axis in alcohol addiction (Section I). Addictions to specific drugs such as alcohol, psychostimulants and opiates (e.g., heroin) have some common direct or downstream effects on several brain stress-responsive systems, including vasopressin and its receptor system (Section II), POMC and mu opioid receptor system (Section III) and dynorphin and kappa opioid receptor systems (Section IV). Further understanding of these systems, through laboratory-based and translational studies, have the potential to optimize early interventions and to discover new treatment targets for the therapy of alcoholism. This article is part of the Special Issue entitled 'CNS Stimulants'.
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Affiliation(s)
- Yan Zhou
- Laboratory of the Biology of Addictive Diseases, The Rockefeller University, 1230 York Avenue, New York, NY 10065, USA
| | - Mary Jeanne Kreek
- Laboratory of the Biology of Addictive Diseases, The Rockefeller University, 1230 York Avenue, New York, NY 10065, USA.
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153
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Wang YJ, Huang P, Blendy JA, Liu-Chen LY. Brain region- and sex-specific alterations in DAMGO-stimulated [(35) S]GTPγS binding in mice with Oprm1 A112G. Addict Biol 2014; 19:354-61. [PMID: 22862850 DOI: 10.1111/j.1369-1600.2012.00484.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The A118G single nucleotide polymorphism (SNP) of the human μ-opioid receptor (MOPR) gene (OPRM1) was associated with heightened dopamine release by alcohol intake, better treatment outcome for nicotine and alcohol addiction, and reduced analgesic responses to morphine. A mouse model that possesses the equivalent substitution (A112G) in the mouse MOPR gene (OPRM1) was generated to delineate the mechanisms of the impact of the SNP. Mice homozygous for the G112 allele (G/G) displayed lower morphine-induced antinociception than mice homozygous for the A112 allele (A/A), similar to the results in humans. In this study, we examined whether A112G SNP affected MOPR-mediated G protein activation in the mouse model. We compared A/A and G/G mice in the MOPR-selective agonist [D-Ala2, N-MePhe4, Gly-ol]-enkephalin (DAMGO)-stimulated [(35) S]GTPγS binding in brain regions by autoradiography. When the data of males and females were combined, G/G mice exhibited lower DAMGO-stimulated [(35) S]GTPγS binding in the ventral tegmental area than A/A mice, in accord with the previously reported reduced morphine-induced hyperactivity and locomotor sensitization in G/G mice. In the nucleus accumbens (NAc) core, female G/G mice displayed lower DAMGO-stimulated [(35) S]GTPγS binding than female A/A mice, which is consistent with the previously reported deficiency in morphine-induced conditioned place preference in female G/G mice. In G/G mice, males showed higher DAMGO-stimulated [(35) S]GTPγS binding than females in the cingulate cortex, caudate putamen, NAc core, thalamus and amygdala. Thus, A112G SNP affects DAMGO-stimulated [(35) S]GTPγS binding in region- and sex-specific manners.
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Affiliation(s)
- Yu-Jun Wang
- Department of Pharmacology; Center for Substance Abuse Research; Temple University School of Medicine; Philadelphia PA USA
| | - Peng Huang
- Department of Pharmacology; Center for Substance Abuse Research; Temple University School of Medicine; Philadelphia PA USA
| | - Julie A. Blendy
- Department of Pharmacology; Perelman School of Medicine; University of Pennsylvania; Philadelphia PA USA
| | - Lee-Yuan Liu-Chen
- Department of Pharmacology; Center for Substance Abuse Research; Temple University School of Medicine; Philadelphia PA USA
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Genetic variation associated with euphorigenic effects of d-amphetamine is associated with diminished risk for schizophrenia and attention deficit hyperactivity disorder. Proc Natl Acad Sci U S A 2014; 111:5968-73. [PMID: 24711425 DOI: 10.1073/pnas.1318810111] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Here, we extended our findings from a genome-wide association study of the euphoric response to d-amphetamine in healthy human volunteers by identifying enrichment between SNPs associated with response to d-amphetamine and SNPs associated with psychiatric disorders. We found that SNPs nominally associated (P ≤ 0.05 and P ≤ 0.01) with schizophrenia and attention deficit hyperactivity disorder were also nominally associated with d-amphetamine response. Furthermore, we found that the source of this enrichment was an excess of alleles that increased sensitivity to the euphoric effects of d-amphetamine and decreased susceptibility to schizophrenia and attention deficit hyperactivity disorder. In contrast, three negative control phenotypes (height, inflammatory bowel disease, and Parkinson disease) did not show this enrichment. Taken together, our results suggest that alleles identified using an acute challenge with a dopaminergic drug in healthy individuals can be used to identify alleles that confer risk for psychiatric disorders commonly treated with dopaminergic agonists and antagonists. More importantly, our results show the use of the enrichment approach as an alternative to stringent standards for genome-wide significance and suggest a relatively novel approach to the analysis of small cohorts in which intermediate phenotypes have been measured.
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155
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Haerian BS, Haerian MS. OPRM1 rs1799971 polymorphism and opioid dependence: evidence from a meta-analysis. Pharmacogenomics 2014; 14:813-24. [PMID: 23651028 DOI: 10.2217/pgs.13.57] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The OPRM1 gene encodes the µ-opioid receptor, which is the primary site of action of most opioids. Several studies and three meta-analyses have examined a possible link between the exonic OPRM1 A118G (rs1799971) polymorphism and opioid dependence; however, results have been inconclusive. Therefore, a systematic review and meta-analysis have been carried out to examine whether this polymorphism is associated with opioid dependence. Thirteen studies (n = 9385), comprising 4601 opioid dependents and 4784 controls, which evaluated association of the OPRM1 rs1799971 polymorphism with susceptibility to opioids, were included in this study. Our meta-analysis showed significant association between this polymorphism and susceptibility to opioid dependence in overall studies under a codominant model, as well as susceptibility to opioid dependence or heroin dependence in Asians under an autosomal dominant model. The nonsynonymous OPRM1 rs1799971 might be a risk factor for addiction to opioids or heroin in an Asian population.
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Affiliation(s)
- Batoul Sadat Haerian
- Department of Pharmacology, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia.
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156
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Ray LA, Bujarski S, Squeglia LM, Ashenhurst JR, Anton RF. Interactive effects of OPRM1 and DAT1 genetic variation on subjective responses to alcohol. Alcohol Alcohol 2014; 49:261-70. [PMID: 24421289 DOI: 10.1093/alcalc/agt183] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
AIMS Subjective response to alcohol represents a marker of alcoholism risk. The A118G single-nucleotide polymorphism (SNP) of the mu opioid receptor (OPRM1) gene has been associated with subjective response to alcohol. Recently, the dopamine transporter (DAT1) variable number of tandem repeat (VNTR; SLC6A3) has been found to interact with the OPRM1 A118G SNP in predicting neural and behavioral responses to naltrexone and to alcohol. This exploratory study examines the OPRM1 × DAT1 interaction on subjective responses to alcohol. METHODS Non-treatment-seeking problem drinkers (n = 295) were assessed in the laboratory for alcohol dependence. Following prospective genotyping for the OPRM1 gene, 43 alcohol-dependent individuals were randomized to two intravenous infusion sessions, one of alcohol (target BrAC = 0.06 g/dl) and one of saline. Measures of subjective responses to alcohol were administered in both infusion sessions. RESULTS Analyses revealed significant Alcohol × OPRM1 × DAT1 interactions for alcohol-induced stimulation, vigor and positive mood as well as significant Alcohol × OPRM1 × DAT1 × Time interactions for stimulation and positive mood. These effects were such that, compared with other genotype groups, OPRM1 G-allele carriers + DAT1 A10 homozygotes reported steeper increases in stimulation and positive mood across rising BrAC, when compared with placebo. All Alcohol × OPRM1 × DAT1 interactions remained significant when analyses were restricted to a subsample of Caucasian participants (n = 34); however, 4-way interactions did not reach statistical significance in this subsample. CONCLUSIONS This study suggests that the contribution of OPRM1 genotype to alcohol-induced stimulation, vigor and positive mood is moderated by DAT1 genotype. These findings are consistent with the purported interaction between opioidergic and dopaminergic systems in determining the reinforcing properties of alcohol.
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Affiliation(s)
- Lara A Ray
- Corresponding author: Department of Psychology, University of California, 1285 Franz Hall, Box 951563, Los Angeles, CA 90095-1563, USA.
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Abstract
Addictions are prevalent psychiatric disorders that confer remarkable personal and social burden. Despite substantial evidence for their moderate, yet robust, heritability (approx. 50%), specific genetic mechanisms underlying their development and maintenance remain unclear. The goal of this selective review is to highlight progress in unveiling the genetic underpinnings of addiction. First, we revisit the basis for heritable variation in addiction before reviewing the most replicable candidate gene findings and emerging signals from genomewide association studies for alcohol, nicotine and cannabis addictions. Second, we survey the modest but growing field of neurogenetics examining how genetic variation influences corticostriatal structure, function, and connectivity to identify neural mechanisms that may underlie associations between genetic variation and addiction. Third, we outline how extant genomic findings are being used to develop and refine pharmacotherapies. Finally, as sample sizes for genetically informed studies of addiction approach critical mass, we posit five exciting possibilities that may propel further discovery (improved phenotyping, rare variant discovery, gene-environment interplay, epigenetics, and novel neuroimaging designs).
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159
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Matsushita S, Higuchi S. Genetic differences in response to alcohol. HANDBOOK OF CLINICAL NEUROLOGY 2014; 125:617-27. [PMID: 25307600 DOI: 10.1016/b978-0-444-62619-6.00036-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
The level of response to alcohol, which reflects individual differences in sensitivity to the pharmacologic effects of alcohol, is considered to be an important endophenotype of alcohol use disorder (AUD). By comparing monozygotic and dizygotic twins, the heritability of the level of response to alcohol has been estimated to be 60%. Many genes have been implicated as potential contributors toward heavy drinking, alcohol-related problems, and AUD through a low level of response to alcohol, each with a small effect. Identified are genes for gamma-aminobutyric acid (GABA) receptors, serotonin transporter, opioid receptor, and nicotinic acetylcholine receptor, but the most well-characterized genes that have a strong impact on the level of response to alcohol are those for alcohol-metabolizing enzymes. Although two genetic variations in alcohol and aldehyde dehydrogenases, which have been the most intensively studied, exist almost exclusively in Asian populations, studies on the effect of genetic variations in alcohol-metabolizing enzymes on the response to alcohol are gradually expanding in non-Asian populations. In this chapter, we focus on genetic studies in humans. After analyzing the overall influence of genetic factors on the response to alcohol, we explore individual genes that may influence the response to alcohol. Lastly, we review studies examining the effects of genetic variations in alcohol-metabolizing enzymes on the level of response to alcohol.
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Affiliation(s)
- Sachio Matsushita
- National Hospital Organization, Kurihama Medical and Addiction Center, Kanagawa, Japan.
| | - Susumu Higuchi
- National Hospital Organization, Kurihama Medical and Addiction Center, Kanagawa, Japan
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160
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Nielsen DA, Nielsen EM, Dasari T, Spellicy CJ. Pharmacogenetics of addiction therapy. Methods Mol Biol 2014; 1175:589-624. [PMID: 25150877 DOI: 10.1007/978-1-4939-0956-8_15] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Drug addiction is a serious relapsing disease that has high costs to society and to the individual addicts. Treatment of these addictions is still in its nascency, with only a few examples of successful therapies. Therapeutic response depends upon genetic, biological, social, and environmental components. A role for genetic makeup in the response to treatment has been shown for several addiction pharmacotherapies. For several addiction pharmacotherapies, response to treatment varies based on individual genetic makeup. In this chapter, we discuss the role of genetics in pharmacotherapies, specifically for cocaine, alcohol, and opioid dependences. The elucidation of the role of genetics should aid in the development of new treatments and increase the efficacy of existing treatments.
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Affiliation(s)
- David A Nielsen
- Menninger Department of Psychiatry and Behavioral Sciences, Baylor College of Medicine, Houston, TX, USA,
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161
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Ravan S, Martinez D, Slifstein M, Abi-Dargham A. Molecular imaging in alcohol dependence. HANDBOOK OF CLINICAL NEUROLOGY 2014; 125:293-311. [PMID: 25307582 DOI: 10.1016/b978-0-444-62619-6.00018-5] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
The cellular mechanisms of alcohol's effects in the brain are complex, targeting multiple transmitter systems. Molecular imaging has been used to study the effects of alcohol and alcohol use disorders on these various systems. Studies of dopaminergic indices have provided robust evidence for deficits in D2-mediated transmission in the striatum of chronic recently detoxified alcoholics. Their presence in the at-risk state prior to excessive drinking, and their recovery after long-term sobriety, are unclear and represent an active area of current research. Investigations of the GABAergic system have shown generalized deficits in various brain regions in the chronic abstinence phase. Studies of the opiate system have suggested alterations in some subtypes in discrete brain regions, including the ventral striatum, while studies of serotonin have been negative and those of the cannabinoid system have been inconclusive. Future investigations should target the glutamatergic system, which plays an important role both in the acute intoxicating effects of alcohol as well as in the long-term effects associated with dependence.
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Affiliation(s)
- Shervin Ravan
- Department of Radiology, Columbia University College of Physicians and Surgeons, New York, NY, USA
| | - Diana Martinez
- Department of Psychiatry, Columbia University College of Physicians and Surgeons, New York, NY, USA
| | - Mark Slifstein
- Department of Psychiatry, Columbia University College of Physicians and Surgeons, New York, NY, USA
| | - Anissa Abi-Dargham
- Department of Radiology, Columbia University College of Physicians and Surgeons, New York, NY, USA; Department of Psychiatry, Columbia University College of Physicians and Surgeons, New York, NY, USA.
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162
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Abstract
This chapter provides an overview of current knowledge on the molecular and clinical aspects of chronic alcohol effects on the central nervous system. This drug is almost ubiquitous, widely enjoyed socially, but produces a diverse spectrum of neurologic disease when abused. Acutely, alcohol interacts predominantly with γ-aminobutyric acid-A (GABA-A) and N-methyl-d-aspartate (NMDA) receptors, but triggers diverse signaling events within well-defined neural pathways. These events result in adaptive changes in gene expression that ultimately produce two major states: addiction and toxicity. Epigenetic modifications of chromatin could lead to long-lived or even transgenerational changes in gene expression, thus producing aspects of the heritability of alcohol use disorders (AUD) and long-term behaviors such as recidivism. The diverse clinical syndromes produced by chronic alcohol actions in the central nervous system reflect the molecular pathology and predominantly involve aspects of tolerance/withdrawal, selective vulnerability (manifest as central pontine myelinolysis, Marchiafava-Bignami disease), and additional environmental factors (e.g., thiamine deficiency in Wernicke-Korsakoff's syndrome). Additionally, deleterious aspects of chronic alcohol on signaling, synaptic transmission, and cell toxicity lead to primary alcoholic dementia. Genetically determined aspects of myelin structure and alcohol actions on myelin gene expression may be a prominent molecular mechanism resulting in a predisposition to, or causation of, AUD and multiple other neurologic complications of chronic alcohol. The dramatic progress made in understanding molecular actions of alcohol holds great promise for our eventual treatment or prevention of AUD and neurologic complications resulting from chronic alcohol abuse.
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Affiliation(s)
- B N Costin
- Virginia Commonwealth University Alcohol Research Center and Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, VA, USA
| | - M F Miles
- Virginia Commonwealth University Alcohol Research Center, Department of Pharmacology and Toxicology, Center for Study of Biological Complexity and Department of Neurology, Virginia Commonwealth University, Richmond, VA, USA.
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163
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Abstract
Aggressive behavior can have adaptive value in certain environmental contexts, but when extreme or executed inappropriately, can also lead to maladaptive outcomes. Neurogenetic studies performed in nonhuman primates have shown that genetic variation that impacts reward sensitivity, impulsivity, and anxiety can contribute to individual differences in aggressive behavior. Genetic polymorphisms in the coding or promoter regions of the Mu-Opioid Receptor (OPRM1), Corticotropin Releasing Hormone (CRH), Monoamine Oxidase A (MAOA), Dopamine D4 Receptor (DRD4), and Serotonin Transporter (SLC6A4) genes have been shown to be functionally similar in humans and rhesus macaques and have been demonstrated to contribute to individual differences in aggression. This body of literature suggests mechanisms by which genetic variation that promotes aggressivity could simultaneously increase evolutionary success while making modern humans more vulnerable to psychopathology.
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Affiliation(s)
- Christina S Barr
- Section of Comparative Behavioral Genomics, Laboratory of Neurogenetics, NIH/NIAAA, Rockville, MD, USA,
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164
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Abstract
Alcoholism, more generically drug addiction, can be defined as a chronically relapsing disorder characterized by: (1) compulsion to seek and take the drug (alcohol); (2) loss of control in limiting (alcohol) intake; and (3) emergence of a negative emotional state (e.g., dysphoria, anxiety, irritability), reflecting a motivational withdrawal syndrome, when access to the drug (alcohol) is prevented (defined here as dependence). The compulsive drug seeking associated with alcoholism can be derived from multiple neuroadaptations, but the thesis argued here, derived largely from animal models, is that a key component involves decreased brain reward function, increased brain stress function, and compromised executive function, all of which contribute to the construct of negative reinforcement. Negative reinforcement is defined as drug taking that alleviates a negative emotional state. The negative emotional state that drives such negative reinforcement is hypothesized to derive from decreases in reward neurotransmission in the ventral striatum, such as decreased dopamine and opioid peptide function in the nucleus accumbens (ventral striatum), but also recruitment of brain stress systems, such as corticotropin-releasing factor (CRF), in the extended amygdala. Data from animal models that support this thesis show that acute withdrawal from chronic alcohol, sufficient to produce dependence, increases reward thresholds, increases anxiety-like responses, decreases dopamine system function, and increases extracellular levels of CRF in the central nucleus of the amygdala. CRF receptor antagonists also block excessive drug intake produced by dependence. Alcoholism also involves substantial neuroadaptations that persist beyond acute withdrawal and trigger relapse and deficits in cognitive function that can also fuel compulsive drinking. A brain stress response system is hypothesized to be activated by acute excessive drug intake, to be sensitized during repeated withdrawal, to persist into protracted abstinence, and to contribute to the compulsivity of alcoholism. Other components of brain stress systems in the extended amygdala that interact with CRF and may contribute to the negative motivational state of withdrawal include increases in norepinephrine function, increases in dynorphin activity, and decreases in neuropeptide Y. The combination of impairment of function in reward circuitry and recruitment of brain stress system circuitry provides a powerful neurochemical basis for the negative emotional states that are responsible for the negative reinforcement that drives the compulsivity of alcoholism.
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Affiliation(s)
- George F Koob
- Committee on the Neurobiology of Addictive Disorders, The Scripps Research Institute, La Jolla, CA, USA.
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165
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Spanagel R. Convergent functional genomics in addiction research - a translational approach to study candidate genes and gene networks. In Silico Pharmacol 2013; 1:18. [PMID: 25505662 PMCID: PMC4230431 DOI: 10.1186/2193-9616-1-18] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2013] [Accepted: 11/12/2013] [Indexed: 01/16/2023] Open
Abstract
Convergent functional genomics (CFG) is a translational methodology that integrates in a Bayesian fashion multiple lines of evidence from studies in human and animal models to get a better understanding of the genetics of a disease or pathological behavior. Here the integration of data sets that derive from forward genetics in animals and genetic association studies including genome wide association studies (GWAS) in humans is described for addictive behavior. The aim of forward genetics in animals and association studies in humans is to identify mutations (e.g. SNPs) that produce a certain phenotype; i.e. "from phenotype to genotype". Most powerful in terms of forward genetics is combined quantitative trait loci (QTL) analysis and gene expression profiling in recombinant inbreed rodent lines or genetically selected animals for a specific phenotype, e.g. high vs. low drug consumption. By Bayesian scoring genomic information from forward genetics in animals is then combined with human GWAS data on a similar addiction-relevant phenotype. This integrative approach generates a robust candidate gene list that has to be functionally validated by means of reverse genetics in animals; i.e. "from genotype to phenotype". It is proposed that studying addiction relevant phenotypes and endophenotypes by this CFG approach will allow a better determination of the genetics of addictive behavior.
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Affiliation(s)
- Rainer Spanagel
- Institute of Psychopharmacology, Central Institute of Mental Health, Faculty of Medicine Mannheim, University of Heidelberg, J5, 68159 Mannheim, Germany
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166
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Björk K, Tronci V, Thorsell A, Tanda G, Hirth N, Heilig M, Hansson AC, Sommer WH. β-Arrestin 2 knockout mice exhibit sensitized dopamine release and increased reward in response to a low dose of alcohol. Psychopharmacology (Berl) 2013; 230:439-49. [PMID: 23779257 PMCID: PMC3817962 DOI: 10.1007/s00213-013-3166-x] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/24/2013] [Accepted: 05/30/2013] [Indexed: 11/26/2022]
Abstract
RATIONALE The rewarding effects of alcohol have been attributed to interactions between opioid and dopaminergic system within the mesolimbic reward pathway. We have previously shown that ablation of β-arrestin 2 (Arrb2), a crucial regulator of μ-opioid receptor function, attenuates alcohol-induced hyperlocomotion and c-fos activation in the nucleus accumbens. OBJECTIVES Here, we further investigated the role of Arrb2 in modulating alcohol-induced dopamine (DA) release and conditioned place preference (CPP). We also assessed the functional importance of Arrb2 for μ-opioid receptor surface expression and signaling following an acute alcohol challenge. METHODS Alcohol-evoked (0.375, 0.75, and 1.5 g/kg intraperitoneally) DA release was measured by in vivo microdialysis in the shell of nucleus accumbens. Reward was assessed by the CPP paradigm. Receptor function was assessed by μ-receptor binding and [(35)S]GTP-γ-S autoradiography. RESULTS In Arrb2 knockout mice accumbal DA levels reach maximum response at a lower dose compared to wild-type (wt) animals. In line with these results, Arrb2 knockout mice display increased CPP for alcohol as compared to wt mice. Finally, Arrb2 mutant mice display increased μ-opioid receptor signaling in the ventral and dorsal striatum and amygdala in response to a low dose of alcohol, indicating impaired desensitization mechanisms in these mice. CONCLUSIONS Our results show that Arrb2 modulates the response to low doses of alcohol on various levels including μ-opioid receptor signaling, DA release, and reward. They also reveal a clear dissociation between the effects of Arrb2 on psychomotor and reward behaviors.
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Affiliation(s)
- Karl Björk
- Translational Neuropharmacology, Department of Clinical Neuroscience, Karolinska Institute, Stockholm, Sweden,
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167
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Jonsson S, Ericson M, Söderpalm B. Modest Long-Term Ethanol Consumption Affects Expression of Neurotransmitter Receptor Genes in the Rat Nucleus Accumbens. Alcohol Clin Exp Res 2013; 38:722-9. [DOI: 10.1111/acer.12307] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2013] [Accepted: 09/27/2013] [Indexed: 01/21/2023]
Affiliation(s)
- Susanne Jonsson
- Department of Psychiatry and Neurochemistry; Institute of Neuroscience and Physiology; The Sahlgrenska Academy at University of Gothenburg and Beroendekliniken; Sahlgrenska University Hospital; Gothenburg Sweden
| | - Mia Ericson
- Department of Psychiatry and Neurochemistry; Institute of Neuroscience and Physiology; The Sahlgrenska Academy at University of Gothenburg and Beroendekliniken; Sahlgrenska University Hospital; Gothenburg Sweden
| | - Bo Söderpalm
- Department of Psychiatry and Neurochemistry; Institute of Neuroscience and Physiology; The Sahlgrenska Academy at University of Gothenburg and Beroendekliniken; Sahlgrenska University Hospital; Gothenburg Sweden
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168
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Enoch MA. Genetic influences on response to alcohol and response to pharmacotherapies for alcoholism. Pharmacol Biochem Behav 2013; 123:17-24. [PMID: 24220019 DOI: 10.1016/j.pbb.2013.11.001] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/03/2013] [Revised: 09/24/2013] [Accepted: 11/04/2013] [Indexed: 12/16/2022]
Abstract
Although very many individuals drink alcohol at safe levels, a significant proportion escalates their consumption with addiction as the end result. Alcoholism is a common, moderately heritable, psychiatric disorder that is accompanied by considerable morbidity and mortality. Variation in clinical presentation suggests inter-individual variation in mechanisms of vulnerability including genetic risk factors. The development of addiction is likely to involve numerous functional genetic variants of small effects. The first part of this review will focus on genetic factors underlying inter-individual variability in response to alcohol consumption, including variants in alcohol metabolizing genes that produce an aversive response (the flushing syndrome) and variants that predict the level of subjective and physiological response to alcohol. The second part of this review will report on genetic variants that identify subgroups of alcoholics who are more likely to respond to pharmacotherapy to reduce levels of drinking or maintain abstinence. Genetic analyses of the level of response to alcohol, particularly of the functional OPRM1 A118G polymorphism and 5' and 3' functional polymorphisms in SLC6A4, are beginning to provide insights into the etiology of alcoholism and also genotype-stratified subgroup responses to naltrexone and SSRIs/ondansetron respectively. Because of large inter-ethnic variation in allele frequencies, the relevance of these functional polymorphisms will vary between ethnic groups. However there are relatively few published studies in this field, particularly with large sample sizes in pharmacogenetic studies, therefore it is premature to draw any conclusions at this stage.
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Affiliation(s)
- Mary-Anne Enoch
- National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, MD 20892, United States.
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169
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Crist RC, Berrettini WH. Pharmacogenetics of OPRM1. Pharmacol Biochem Behav 2013; 123:25-33. [PMID: 24201053 DOI: 10.1016/j.pbb.2013.10.018] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/08/2013] [Revised: 09/19/2013] [Accepted: 10/23/2013] [Indexed: 12/23/2022]
Abstract
Pharmacogenetic research has the potential to explain the variation in treatment efficacy within patient populations. Understanding the interaction between genetic variation and medications may provide a method for matching patients to the most effective therapeutic options and improving overall patient outcomes. The OPRM1 gene has been a target of interest in a large number of pharmacogenetic studies due to its genetic and structural variation, as well as the role of opioid receptors in a variety of disorders. The mu-opioid receptor (MOR), encoded by OPRM1, naturally regulates the analgesic response to pain and also controls the rewarding effects of many drugs of abuse, including opioids, nicotine, and alcohol. Genetic variants in OPRM1, particularly the non-synonymous polymorphism A118G, have been repeatedly associated with the efficacy of treatments for pain and various types of dependence. This review focuses on the current understanding of the pharmacogenetic impact of OPRM1, primarily with regard to the treatment of pain and addiction.
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Affiliation(s)
- Richard C Crist
- Center for Neurobiology and Behavior, Department of Psychiatry, University of Pennsylvania School of Medicine, 125 South 31st St., Philadelphia, PA 19104, United States.
| | - Wade H Berrettini
- Center for Neurobiology and Behavior, Department of Psychiatry, University of Pennsylvania School of Medicine, 125 South 31st St., Philadelphia, PA 19104, United States
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170
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Spanagel R, Durstewitz D, Hansson A, Heinz A, Kiefer F, Köhr G, Matthäus F, Nöthen MM, Noori HR, Obermayer K, Rietschel M, Schloss P, Scholz H, Schumann G, Smolka M, Sommer W, Vengeliene V, Walter H, Wurst W, Zimmermann US, Stringer S, Smits Y, Derks EM. A systems medicine research approach for studying alcohol addiction. Addict Biol 2013; 18:883-96. [PMID: 24283978 DOI: 10.1111/adb.12109] [Citation(s) in RCA: 72] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
According to the World Health Organization, about 2 billion people drink alcohol. Excessive alcohol consumption can result in alcohol addiction, which is one of the most prevalent neuropsychiatric diseases afflicting our society today. Prevention and intervention of alcohol binging in adolescents and treatment of alcoholism are major unmet challenges affecting our health-care system and society alike. Our newly formed German SysMedAlcoholism consortium is using a new systems medicine approach and intends (1) to define individual neurobehavioral risk profiles in adolescents that are predictive of alcohol use disorders later in life and (2) to identify new pharmacological targets and molecules for the treatment of alcoholism. To achieve these goals, we will use omics-information from epigenomics, genetics transcriptomics, neurodynamics, global neurochemical connectomes and neuroimaging (IMAGEN; Schumann et al. ) to feed mathematical prediction modules provided by two Bernstein Centers for Computational Neurosciences (Berlin and Heidelberg/Mannheim), the results of which will subsequently be functionally validated in independent clinical samples and appropriate animal models. This approach will lead to new early intervention strategies and identify innovative molecules for relapse prevention that will be tested in experimental human studies. This research program will ultimately help in consolidating addiction research clusters in Germany that can effectively conduct large clinical trials, implement early intervention strategies and impact political and healthcare decision makers.
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Affiliation(s)
- Rainer Spanagel
- Insitute of Psychopharmacology; Central Institute of Mental Health; Medical Faculty Mannheim; University of Heidelberg; Germany
| | - Daniel Durstewitz
- Bernstein Center for Computational Neuroscience; Central Institute of Mental Health; Germany
| | - Anita Hansson
- Insitute of Psychopharmacology; Central Institute of Mental Health; Medical Faculty Mannheim; University of Heidelberg; Germany
| | - Andreas Heinz
- Department of Addictive Behaviour and Addiction Medicine; Central Institute of Mental Health; Germany
| | - Falk Kiefer
- Department of Genetic Epidemiology in Psychiatry; Central Institute of Mental Health; Germany
| | - Georg Köhr
- Insitute of Psychopharmacology; Central Institute of Mental Health; Medical Faculty Mannheim; University of Heidelberg; Germany
| | | | - Markus M. Nöthen
- Department of Psychiatry; Charité University Medical Center; Germany
| | - Hamid R. Noori
- Insitute of Psychopharmacology; Central Institute of Mental Health; Medical Faculty Mannheim; University of Heidelberg; Germany
| | - Klaus Obermayer
- Institute of Applied Mathematics; University of Heidelberg; Germany
| | - Marcella Rietschel
- Department of Genomics, Life & Brain Centre; University of Bonn; Germany
| | - Patrick Schloss
- Neural Information Processing Group; Technical University of Berlin; Germany
| | - Henrike Scholz
- Behavioral Neurogenetics' Zoological Institute; University of Cologne; Germany
| | - Gunter Schumann
- MRC-SGDP Centre; Institute of Psychiatry; King's College; UK
| | - Michael Smolka
- Department of Psychiatry and Psychotherapy; Technical University Dresden; Germany
| | - Wolfgang Sommer
- Insitute of Psychopharmacology; Central Institute of Mental Health; Medical Faculty Mannheim; University of Heidelberg; Germany
| | - Valentina Vengeliene
- Insitute of Psychopharmacology; Central Institute of Mental Health; Medical Faculty Mannheim; University of Heidelberg; Germany
| | - Henrik Walter
- Department of Addictive Behaviour and Addiction Medicine; Central Institute of Mental Health; Germany
| | - Wolfgang Wurst
- Institute of Developmental Genetics; Helmholtz Center Munich; Germany
| | - Uli S. Zimmermann
- Department of Psychiatry and Psychotherapy; Technical University Dresden; Germany
| | - Sven Stringer
- Psychiatry Department; Academic Medical Center; The Netherlands
- Brain Center Rudolf Magnus; University Medical Center; The Netherlands
| | - Yannick Smits
- Psychiatry Department; Academic Medical Center; The Netherlands
| | - Eske M. Derks
- Psychiatry Department; Academic Medical Center; The Netherlands
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171
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Neuroimaging in psychiatric pharmacogenetics research: the promise and pitfalls. Neuropsychopharmacology 2013; 38:2327-37. [PMID: 23793356 PMCID: PMC3799069 DOI: 10.1038/npp.2013.152] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/15/2013] [Revised: 06/10/2013] [Accepted: 06/10/2013] [Indexed: 12/22/2022]
Abstract
The integration of research on neuroimaging and pharmacogenetics holds promise for improving treatment for neuropsychiatric conditions. Neuroimaging may provide a more sensitive early measure of treatment response in genetically defined patient groups, and could facilitate development of novel therapies based on an improved understanding of pathogenic mechanisms underlying pharmacogenetic associations. This review summarizes progress in efforts to incorporate neuroimaging into genetics and treatment research on major psychiatric disorders, such as schizophrenia, major depressive disorder, bipolar disorder, attention-deficit/hyperactivity disorder, and addiction. Methodological challenges include: performing genetic analyses in small study populations used in imaging studies; inclusion of patients with psychiatric comorbidities; and the extensive variability across studies in neuroimaging protocols, neurobehavioral task probes, and analytic strategies. Moreover, few studies use pharmacogenetic designs that permit testing of genotype × drug effects. As a result of these limitations, few findings have been fully replicated. Future studies that pre-screen participants for genetic variants selected a priori based on drug metabolism and targets have the greatest potential to advance the science and practice of psychiatric treatment.
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172
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Wong CJ, Witcher J, Mallinckrodt C, Dean RA, Anton RF, Chen Y, Fijal BA, Ouyang H, Dharia S, Sundseth SS, Schuh KJ, Kinon BJ. A Phase 2, Placebo-Controlled Study of the Opioid Receptor Antagonist LY2196044 for the Treatment of Alcohol Dependence. Alcohol Clin Exp Res 2013; 38:511-20. [DOI: 10.1111/acer.12257] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2012] [Accepted: 06/11/2013] [Indexed: 12/01/2022]
Affiliation(s)
- Conrad J. Wong
- Eli Lilly and Company and/or one of its wholly owned subsidiaries; Indianapolis Indiana USA
| | - Jennifer Witcher
- Eli Lilly and Company and/or one of its wholly owned subsidiaries; Indianapolis Indiana USA
| | - Craig Mallinckrodt
- Eli Lilly and Company and/or one of its wholly owned subsidiaries; Indianapolis Indiana USA
| | - Robert A. Dean
- Eli Lilly and Company and/or one of its wholly owned subsidiaries; Indianapolis Indiana USA
| | - Raymond F. Anton
- Medical University of South Carolina; Charleston South Carolina USA
| | - Yunfei Chen
- Eli Lilly and Company and/or one of its wholly owned subsidiaries; Indianapolis Indiana USA
| | - Bonnie A. Fijal
- Eli Lilly and Company and/or one of its wholly owned subsidiaries; Indianapolis Indiana USA
| | - Haojun Ouyang
- Eli Lilly and Company and/or one of its wholly owned subsidiaries; Indianapolis Indiana USA
| | - Sweta Dharia
- Eli Lilly and Company and/or one of its wholly owned subsidiaries; Indianapolis Indiana USA
| | | | - Kory J. Schuh
- Eli Lilly and Company and/or one of its wholly owned subsidiaries; Indianapolis Indiana USA
| | - Bruce J. Kinon
- Eli Lilly and Company and/or one of its wholly owned subsidiaries; Indianapolis Indiana USA
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173
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Ziauddeen H, Nathan PJ, Dodds C, Maltby K, Miller SR, Waterworth D, Song K, Warren L, Hosking L, Zucchetto M, Bush M, Johnson LV, Sarai B, Mogg K, Bradley BP, Richards DB, Fletcher PC, Bullmore ET. The effects of alcohol on the pharmacokinetics and pharmacodynamics of the selective mu-opioid receptor antagonist GSK1521498 in healthy subjects. J Clin Pharmacol 2013; 53:1078-90. [PMID: 23934621 PMCID: PMC4282435 DOI: 10.1002/jcph.110] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2013] [Accepted: 05/11/2013] [Indexed: 11/27/2022]
Abstract
The mu-opioid system has a key role in hedonic and motivational processes critical to substance addiction. However, existing mu-opioid antagonists have had limited success as anti-addiction treatments. GSK1521498 is a selective and potent mu-opioid antagonist being developed for the treatment of overeating and substance addictions. In this study, 28 healthy participants were administered single doses of GSK1521498 20 mg, ethanol 0.5 g/kg body weight, or both in combination, in a double blind placebo controlled four-way crossover design. The primary objective was to determine the risk of significant adverse pharmacodynamic and pharmacokinetic (PK) interactions. The effects of GSK1521498 on hedonic and consummatory responses to alcohol and the attentional processing of alcohol-related stimuli, and their modulation by the OPRM1 A118G polymorphism were also explored. GSK1521498 20 mg was well tolerated alone and in combination with ethanol. There were mild transient effects of GSK1521498 on alertness and mood that were greater when it was combined with ethanol. These effects were not of clinical significance. There were no effects of GSK1521498 on reaction time, hedonic or consummatory responses. These findings provide encouraging safety and PK data to support continued development of GSK1521498 for the treatment of alcohol addiction.
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Affiliation(s)
- Hisham Ziauddeen
- Medicines Discovery and Development, GlaxoSmithKline, Clinical Unit Cambridge, Addenbrooke's Centre for Clinical Investigations, Cambridge, UK; Department of Psychiatry, Behavioural and Clinical Neuroscience Institute, Cambridge Biomedical Campus, University of Cambridge, Cambridge, UK; Metabolic Research Laboratories, Institute of Metabolic Science, University of Cambridge, Cambridge, UK; Cambridgeshire and Peterborough NHS Foundation Trust (CPFT), Cambridge, UK
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174
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Setiawan E, Pihl RO, Dagher A, Schlagintweit H, Casey KF, Benkelfat C, Leyton M. Differential Striatal Dopamine Responses Following Oral Alcohol in Individuals at Varying Risk for Dependence. Alcohol Clin Exp Res 2013; 38:126-34. [DOI: 10.1111/acer.12218] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2012] [Accepted: 05/15/2013] [Indexed: 11/26/2022]
Affiliation(s)
- Elaine Setiawan
- Department of Psychiatry; McGill University; Montréal Québec Canada
- Department of Neurology and Neurosurgery; McGill University; Montréal Québec Canada
| | - Robert O. Pihl
- Department of Psychiatry; McGill University; Montréal Québec Canada
- Department of Psychology; McGill University; Montréal Québec Canada
| | - Alain Dagher
- Department of Neurology and Neurosurgery; McGill University; Montréal Québec Canada
| | | | - Kevin F. Casey
- Department of Psychiatry; McGill University; Montréal Québec Canada
- Department of Neurology and Neurosurgery; McGill University; Montréal Québec Canada
| | - Chawki Benkelfat
- Department of Psychiatry; McGill University; Montréal Québec Canada
- Department of Neurology and Neurosurgery; McGill University; Montréal Québec Canada
| | - Marco Leyton
- Department of Psychiatry; McGill University; Montréal Québec Canada
- Department of Neurology and Neurosurgery; McGill University; Montréal Québec Canada
- Department of Psychology; McGill University; Montréal Québec Canada
- Center for Studies in Behavioral Neurobiology; Concordia University; Montréal Québec Canada
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175
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Oberlin BG, Dzemidzic M, Tran SM, Soeurt CM, Albrecht DS, Yoder KK, Kareken DA. Beer flavor provokes striatal dopamine release in male drinkers: mediation by family history of alcoholism. Neuropsychopharmacology 2013; 38:1617-24. [PMID: 23588036 PMCID: PMC3717546 DOI: 10.1038/npp.2013.91] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/16/2013] [Revised: 04/08/2013] [Accepted: 04/09/2013] [Indexed: 11/09/2022]
Abstract
Striatal dopamine (DA) is increased by virtually all drugs of abuse, including alcohol. However, drug-associated cues are also known to provoke striatal DA transmission- a phenomenon linked to the motivated behaviors associated with addiction. To our knowledge, no one has tested if alcohol's classically conditioned flavor cues, in the absence of a significant pharmacologic effect, are capable of eliciting striatal DA release in humans. Employing positron emission tomography (PET), we hypothesized that beer's flavor alone can reduce the binding potential (BP) of [(11)C]raclopride (RAC; a reflection of striatal DA release) in the ventral striatum, relative to an appetitive flavor control. Forty-nine men, ranging from social to heavy drinking, mean age 25, with a varied family history of alcoholism underwent two [(11)C]RAC PET scans: one while tasting beer, and one while tasting Gatorade. Relative to the control flavor of Gatorade, beer flavor significantly increased self-reported desire to drink, and reduced [(11)C]RAC BP, indicating that the alcohol-associated flavor cues induced DA release. BP reductions were strongest in subjects with first-degree alcoholic relatives. These results demonstrate that alcohol-conditioned flavor cues can provoke ventral striatal DA release, absent significant pharmacologic effects, and that the response is strongest in subjects with a greater genetic risk for alcoholism. Striatal DA responses to salient alcohol cues may thus be an inherited risk factor for alcoholism.
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Affiliation(s)
- Brandon G Oberlin
- Department of Neurology, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Mario Dzemidzic
- Department of Neurology, Indiana University School of Medicine, Indianapolis, IN, USA,Department of Radiology and Imaging Sciences, Center for Neuroimaging, Indiana University School of Medicine, Indianapolis, Indiana, USA
| | - Stella M Tran
- Department of Neurology, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Christina M Soeurt
- Department of Neurology, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Daniel S Albrecht
- Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis, Indiana, USA
| | - Karmen K Yoder
- Department of Radiology and Imaging Sciences, Center for Neuroimaging, Indiana University School of Medicine, Indianapolis, Indiana, USA,Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis, Indiana, USA
| | - David A Kareken
- Department of Neurology, Indiana University School of Medicine, Indianapolis, IN, USA,Department of Radiology and Imaging Sciences, Center for Neuroimaging, Indiana University School of Medicine, Indianapolis, Indiana, USA,Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis, Indiana, USA,Department of Psychiatry, Indiana University School of Medicine, Indianapolis, Indiana, USA,Department of Neurology, Indiana University School of Medicine, 355 W 16th Street, Suite 4700, Indianapolis, IN 46202, Indiana, Tel: +1 317 963 7204, Fax: +1 317 963 7211, E-mail:
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176
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Valenta JP, Job MO, Mangieri RA, Schier CJ, Howard EC, Gonzales RA. μ-opioid receptors in the stimulation of mesolimbic dopamine activity by ethanol and morphine in Long-Evans rats: a delayed effect of ethanol. Psychopharmacology (Berl) 2013; 228:389-400. [PMID: 23503684 PMCID: PMC3707954 DOI: 10.1007/s00213-013-3041-9] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/14/2012] [Accepted: 02/19/2013] [Indexed: 11/28/2022]
Abstract
RATIONALE Naltrexone, a non-selective opioid antagonist, decreases the euphoria and positive subjective responses to alcohol in heavy drinkers. It has been proposed that the μ-opioid receptor plays a role in ethanol reinforcement through modulation of ethanol-stimulated mesolimbic dopamine release. OBJECTIVES To investigate the ability of naltrexone and β-funaltrexamine, an irreversible μ-opioid specific antagonist, to inhibit ethanol-stimulated and morphine-stimulated mesolimbic dopamine release, and to determine whether opioid receptors on mesolimbic neurons contribute to these mechanisms. METHODS Ethanol-naïve male Long Evans rats were given opioid receptor antagonists either intravenously, subcutaneously, or intracranially into the ventral tegmental area (VTA), followed by intravenous administration of ethanol or morphine. We measured extracellular dopamine in vivo using microdialysis probes inserted into the nucleus accumbens shell (n = 114). RESULTS Administration of naltrexone (intravenously) and β-funaltrexamine (subcutaneously), as well as intracranial injection of naltrexone into the VTA did not prevent the initiation of dopamine release by intravenous ethanol administration, but prevented it from being as prolonged. In contrast, morphine-stimulated mesolimbic dopamine release was effectively suppressed. CONCLUSIONS Our results provide novel evidence that there are two distinct mechanisms that mediate ethanol-stimulated mesolimbic dopamine release (an initial phase and a delayed phase), and that opioid receptor activation is required to maintain the delayed-phase dopamine release. Moreover, μ-opioid receptors account for this delayed-phase dopamine response, and the VTA is potentially the site of action of this mechanism. We conclude that μ-opioid receptors play different roles in the mechanisms of stimulation of mesolimbic dopamine activity by ethanol and morphine.
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Affiliation(s)
- John P Valenta
- College of Pharmacy, Department of Pharmacology, University of Texas at Austin, 2409 University Avenue, Stop A1900, Austin, TX 78712-1113, USA
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177
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Ray LA, Courtney KE, Hutchison KE, Mackillop J, Galvan A, Ghahremani DG. Initial evidence that OPRM1 genotype moderates ventral and dorsal striatum functional connectivity during alcohol cues. Alcohol Clin Exp Res 2013; 38:78-89. [PMID: 23876228 DOI: 10.1111/acer.12136] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2012] [Accepted: 03/11/2013] [Indexed: 12/16/2022]
Abstract
BACKGROUND Endogenous opioids and striatal dopamine have been implicated in cue-induced alcohol craving and have been hypothesized to play a role in goal-directed, as opposed to habitual, alcohol use. This initial study examines dorsal and ventral striatal functional connectivity during alcohol-cue processing as a function of the A118G single-nucleotide polymorphism of the mu-opioid receptor (OPRM1) gene. METHODS Seventeen individuals with alcohol dependence (6 females; 90% Caucasian; mean age = 29.4) underwent blood oxygen level-dependent functional magnetic resonance imaging, while performing an alcohol taste-cues task. Psychophysiological interaction analyses investigated associations of the OPRM1 genotype with ventral and dorsal striatum functional connectivity, using the ventral striatum and the caudate as the seed region, respectively. RESULTS Compared to A-allele homozygotes, G-allele carriers of the OPRM1 gene showed (i) greater activation of the insula and orbitofrontal cortex and (ii) stronger negative fronto-striatal functional connectivity for both ventral and dorsal striatal seed regions during processing of alcohol versus water cues. CONCLUSIONS These preliminary findings suggest that, relative to A-allele homozygotes, G-allele carriers show unstable frontal regulation over reward and/or habit-driven inputs from the striatum resulting from greater reward sensitivity combined with limited self-control resources.
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Affiliation(s)
- Lara A Ray
- Department of Psychology , University of California, Los Angeles, California; Department of Psychiatry and Biobehavioral Sciences , University of California, Los Angeles, California
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178
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Abstract
Alcohol addiction is one of the most common and devastating diseases in the world. Given the tremendous heterogeneity of alcohol-addicted individuals, it is unlikely that one medication will help nearly all patients. Thus, there is a clear need to develop predictors of response to existing medications. Naltrexone is a μ-opioid receptor antagonist, which has been approved in the United States for treatment of alcohol addiction since 1994. It has limited efficacy, in part because of noncompliance, but many patients do not respond despite high levels of compliance. There are reports that a missense single nucleotide polymorphism (rs179919 or A118G) in the μ-opioid receptor gene predicts a favorable response to naltrexone if an individual carries a "G" allele. This work will review the evidence for this hypothesis. The data are promising that the "G" allele predisposes to a beneficial naltrexone response among alcohol-addicted persons, but additional research is needed to prove this hypothesis in prospective clinical trials.
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Affiliation(s)
- Wade Berrettini
- Center for Neurobiology and Behavior, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA.
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179
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Rouvinen-Lagerström N, Lahti J, Alho H, Kovanen L, Aalto M, Partonen T, Silander K, Sinclair D, Räikkönen K, Eriksson JG, Palotie A, Koskinen S, Saarikoski ST. μ-Opioid receptor gene (OPRM1) polymorphism A118G: lack of association in Finnish populations with alcohol dependence or alcohol consumption. Alcohol Alcohol 2013; 48:519-25. [PMID: 23729673 PMCID: PMC4296254 DOI: 10.1093/alcalc/agt050] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Aims: The molecular epidemiological studies on the association of the opioid receptor µ-1 (OPRM1) polymorphism A118G (Asn40Asp, rs1799971) and alcohol use disorders have given conflicting results. The aim of this study was to test the possible association of A118G polymorphism and alcohol use disorders and alcohol consumption in three large cohort-based study samples. Methods: The association between the OPRM1 A118G (Asn40Asp, rs1799971) polymorphism and alcohol use disorders and alcohol consumption was analyzed using three different population-based samples: (a) a Finnish cohort study, Health 2000, with 503 participants having a DSM-IV diagnosis for alcohol dependence and/or alcohol abuse and 506 age- and sex-matched controls; (b) a Finnish cohort study, FINRISK (n = 2360) and (c) the Helsinki Birth Cohort Study (n = 1384). The latter two populations lacked diagnosis-based phenotypes, but included detailed information on alcohol consumption. Results: We found no statistically significant differences in genotypic or allelic distribution between controls and subjects with alcohol dependence or abuse diagnoses. Likewise no significant effects were observed between the A118G genotype and alcohol consumption. Conclusion: These results suggest that A118G (Asn40Asp) polymorphism may not have a major effect on the development of alcohol use disorders at least in the Finnish population.
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Affiliation(s)
- Noora Rouvinen-Lagerström
- Ministry of Social Affairs and Health, Department of Occupational Safety and Health, PO Box 33, FI-00023 Government, Finland
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Abstract
Classical conditioning is widely used to study motivational properties of addictive drugs in animals, but has rarely been used in humans. We established a procedure suitable for studying the neurobiology and individual determinants of classical conditioning in humans. Healthy volunteers were randomly assigned to four groups that received methamphetamine or placebo in the presence of distinctive environmental cues under paired or unpaired conditions. During each session, subjects performed tasks known to activate the ventral striatum. Tasks were performed in the presence of a distinctive context, consisting of a screen background image of a beach or mountains, accompanied by corresponding sounds. Separate groups of subjects carried out the tasks under high ($35-50) or low ($5-20) reward conditions. Within each of the two reward conditions, one group (paired) received methamphetamine (20 mg, oral) or placebo consistently associated with one of the contexts, while the other (unpaired) received drug or placebo unrelated to context. A fifth group (paired) performed the tasks with contextual cues but in the absence of monetary incentives. Before and after conditioning, participants carried out a series of forced choice tasks for the contextual cues, and change of preference over time was analyzed. All paired groups showed a significant increase in preference for the drug-associated context, with a linear trend for increase across the levels of reward. Preference was unrelated to subjective drug effects, and did not change in the unpaired group. These data support the translational utility of our conditioning procedure for studies of reward mechanisms in humans.
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181
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Mura E, Govoni S, Racchi M, Carossa V, Ranzani GN, Allegri M, van Schaik RH. Consequences of the 118A>G polymorphism in the OPRM1 gene: translation from bench to bedside? J Pain Res 2013; 6:331-53. [PMID: 23658496 PMCID: PMC3645947 DOI: 10.2147/jpr.s42040] [Citation(s) in RCA: 71] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
The 118A>G single nucleotide polymorphism (SNP) in the μ-opioid receptor (OPRM1) gene has been the most described variant in pharmacogenetic studies regarding opioid drugs. Despite evidence for an altered biological function encoded by this variant, this knowledge is not yet utilized clinically. The aim of the present review was to collect and discuss the available information on the 118A>G SNP in the OPRM1 gene, at the molecular level and in its clinical manifestations. In vitro biochemical and molecular assays have shown that the variant receptor has higher binding affinity for β-endorphins, that it has altered signal transduction cascade, and that it has a lower expression compared with wild-type OPRM1. Studies using animal models for 118A>G have revealed a double effect of the variant receptor, with an apparent gain of function with respect to the response to endogenous opioids but a loss of function with exogenous administered opioid drugs. Although patients with this variant have shown a lower pain threshold and a higher drug consumption in order to achieve the analgesic effect, clinical experiences have demonstrated that patients carrying the variant allele are not affected by the increased opioid consumption in terms of side effects.
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Affiliation(s)
- Elisa Mura
- Department of Drug Sciences, Centre of Excellence in Applied Biology, University of Pavia, Pavia, Italy
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182
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Abstract
AIMS To evaluate the pharmacogenetic evidence relating to the use of opioid antagonists (in particular naltrexone) in treating patients with alcohol abuse problems. METHODS Narrative review of pre-clinical and clinical published research regarding genetic modulation of psychotropic effects produced by alcohol and the therapeutic effects of opioid antagonists. RESULTS Alcohol activates brain reward pathways, leading to positive reinforcement of alcohol seeking and consumption. Thus, the underlying biological mechanisms may be targets for treatment, particularly in the early stages of addiction development. Alcohol reward is in part mediated by endogenous opioids. A single-nucleotide polymorphism (SNP) within the OPRM1 gene, A118G, leading to an amino acid change (Asn40Asp) in the extracellular portion of the receptor, has been implicated in alcoholism as well as in drug addiction, pain sensitivity and stress response, and in animal and human studies relates to the alcohol-dependent phenotype as well as to the treatment response to the µ-opioid antagonist naltrexone. CONCLUSION The effect size reported in naltrexone clinical studies is often small, which may be due to heterogeneity among patients. Pharmacogenetic approaches may help guide us in the search for the appropriate treatment optimal for one patient's need.
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Affiliation(s)
- Annika Thorsell
- Department of Clinical and Experimental Medicine, Linköping University, SE-581 83 Linköping, Sweden.
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183
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Karoly HC, Harlaar N, Hutchison KE. Substance use disorders: a theory-driven approach to the integration of genetics and neuroimaging. Ann N Y Acad Sci 2013; 1282:71-91. [DOI: 10.1111/nyas.12074] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Affiliation(s)
- Hollis C. Karoly
- Department of Psychology and Neuroscience; University of Colorado at Boulder; Boulder; Colorado
| | - Nicole Harlaar
- Department of Psychology and Neuroscience; University of Colorado at Boulder; Boulder; Colorado
| | - Kent E. Hutchison
- Department of Psychology and Neuroscience; University of Colorado at Boulder; Boulder; Colorado
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184
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Daher M, Costa FMM, Neves FAR. Genotyping the Mu-Opioid Receptor A118G Polymorphism Using the Real-time Amplification Refractory Mutation System: Allele Frequency Distribution Among Brazilians. Pain Pract 2013; 13:614-20. [DOI: 10.1111/papr.12042] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2012] [Accepted: 01/22/2013] [Indexed: 02/06/2023]
Affiliation(s)
- Mauricio Daher
- Department of Anesthesiology, University Hospital of Brasilia, University of Brasilia, Brasilia, Brazil
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185
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Schacht JP, Anton RF, Voronin KE, Randall PK, Li X, Henderson S, Myrick H. Interacting effects of naltrexone and OPRM1 and DAT1 variation on the neural response to alcohol cues. Neuropsychopharmacology 2013; 38:414-22. [PMID: 23032071 PMCID: PMC3547192 DOI: 10.1038/npp.2012.195] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Variation at a single nucleotide polymorphism in the μ-opioid receptor gene (OPRM1), A118G (Asn40Asp), may moderate naltrexone (NTX) effects in alcohol dependence. Both NTX and A118G variation have also been reported to affect alcohol cue-elicited brain activation. This study investigated whether sub-acute NTX treatment and A118G genotype interacted in their effects on cue-elicited activation of the ventral striatum (VS), medial prefrontal cortex (mPFC), and orbitofrontal cortex (OFC). Secondarily, variation at a variable number tandem repeat polymorphism in the dopamine transporter gene (DAT1/SLC6A3), which has been associated with increased reward-related activation in VS, was analyzed as a moderator of medication and A118G effects. Seventy-four non-treatment-seeking alcohol-dependent individuals, half preselected to carry at least one copy of the A118G G (Asp) allele, were randomized to NTX (50 mg) or placebo for 7 days, and performed an fMRI alcohol cue reactivity task on day 6. Region-of-interest analyses indicated no main effects of medication or A118G genotype. However, these factors interacted in their effects on OFC activation, such that, among NTX-treated individuals, G-allele carriers had less activation than A-allele homozygotes. DAT1 variation also moderated medication/A118G effects. There was a three-way interaction between medication and A118G and DAT1 genotypes on VS activation, such that, among G-allele carriers who received NTX, DAT1 10-repeat-allele (10R) homozygotes had less activation than 9-repeat-allele (9R) carriers. Further, 10R homozygotes who received NTX had less mPFC activation than 9R carriers. Polymorphic variation in OPRM1 and DAT1 should be considered in future studies of NTX, particularly regarding its effects on reward processing.
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Affiliation(s)
- Joseph P Schacht
- Department of Psychiatry and Behavioral Sciences, Medical University of South Carolina, Charleston, SC 29425, USA.
| | - Raymond F Anton
- Department of Psychiatry and Behavioral Sciences, Medical University of South Carolina, Charleston, SC, USA
| | - Konstantin E Voronin
- Department of Psychiatry and Behavioral Sciences, Medical University of South Carolina, Charleston, SC, USA
| | - Patrick K Randall
- Department of Psychiatry and Behavioral Sciences, Medical University of South Carolina, Charleston, SC, USA
| | - Xingbao Li
- Department of Psychiatry and Behavioral Sciences, Medical University of South Carolina, Charleston, SC, USA
| | - Scott Henderson
- Department of Psychiatry and Behavioral Sciences, Medical University of South Carolina, Charleston, SC, USA
| | - Hugh Myrick
- Department of Psychiatry and Behavioral Sciences, Medical University of South Carolina, Charleston, SC, USA,Ralph H Johnson VA Medical Center, Charleston, SC, USA
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186
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Abstract
In this paper, we consider the concept of food addiction from a clinical and neuroscientific perspective. Food addiction has an established and growing currency in the context of models of overeating and obesity, and its acceptance shapes debate and research. However, we argue that the evidence for its existence in humans is actually rather limited and, in addition, there are fundamental theoretical difficulties that require consideration. We therefore review food addiction as a phenotypic description, one that is based on overlap between certain eating behaviours and substance dependence. To begin, we consider limitations in the general application of this concept to obesity. We share the widely held view that such a broad perspective is not sustainable and consider a more focused view: that it underlies particular eating patterns, notably binge eating. However, even with this more specific focus, there are still problems. Validation of food addiction at the neurobiological level is absolutely critical, but there are inconsistencies in the evidence from humans suggesting that caution should be exercised in accepting food addiction as a valid concept. We argue the current evidence is preliminary and suggest directions for future work that may provide more useful tests of the concept.
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Affiliation(s)
- H Ziauddeen
- Department of Psychiatry, University of Cambridge, Cambridge, UK
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187
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Koob GF. Theoretical frameworks and mechanistic aspects of alcohol addiction: alcohol addiction as a reward deficit disorder. Curr Top Behav Neurosci 2013; 13:3-30. [PMID: 21744309 PMCID: PMC3448980 DOI: 10.1007/7854_2011_129] [Citation(s) in RCA: 177] [Impact Index Per Article: 16.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Alcoholism can be defined by a compulsion to seek and take drug, loss of control in limiting intake, and the emergence of a negative emotional state when access to the drug is prevented. Alcoholism impacts multiple motivational mechanisms and can be conceptualized as a disorder that includes a progression from impulsivity (positive reinforcement) to compulsivity (negative reinforcement). The compulsive drug seeking associated with alcoholism can be derived from multiple neuroadaptations, but the thesis argued here is that a key component involves the construct of negative reinforcement. Negative reinforcement is defined as drug taking that alleviates a negative emotional state. The negative emotional state that drives such negative reinforcement is hypothesized to derive from dysregulation of specific neurochemical elements involved in reward and stress within the basal forebrain structures involving the ventral striatum and extended amygdala, respectively. Specific neurochemical elements in these structures include not only decreases in reward neurotransmission, such as decreased dopamine and γ-aminobutyric acid function in the ventral striatum, but also recruitment of brain stress systems, such as corticotropin-releasing factor (CRF), in the extended amygdala. Acute withdrawal from chronic alcohol, sufficient to produce dependence, increases reward thresholds, increases anxiety-like responses, decreases dopamine system function, and increases extracellular levels of CRF in the central nucleus of the amygdala. CRF receptor antagonists also block excessive drug intake produced by dependence. A brain stress response system is hypothesized to be activated by acute excessive drug intake, to be sensitized during repeated withdrawal, to persist into protracted abstinence, and to contribute to the compulsivity of alcoholism. Other components of brain stress systems in the extended amygdala that interact with CRF and that may contribute to the negative motivational state of withdrawal include norepinephrine, dynorphin, and neuropeptide Y. The combination of loss of reward function and recruitment of brain stress systems provides a powerful neurochemical basis for a negative emotional state that is responsible for the negative reinforcement driving, at least partially, the compulsivity of alcoholism.
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Affiliation(s)
- George F Koob
- Committee on the Neurobiology of Addictive Disorders, The Scripps Research Institute, 10550 North Torrey Pines Road, SP30-2400, La Jolla, CA 92037, USA.
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188
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Kranzler HR, Armeli S, Covault J, Tennen H. Variation in OPRM1 moderates the effect of desire to drink on subsequent drinking and its attenuation by naltrexone treatment. Addict Biol 2013; 18:193-201. [PMID: 22784013 DOI: 10.1111/j.1369-1600.2012.00471.x] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
To evaluate the role of the functional Asn40Asp polymorphism in the mu-opioid receptor gene on drinking behavior and naltrexone's ability to attenuate drinking, we used a daily diary method in a 12-week, randomized clinical trial of naltrexone to reduce drinking. Participants (n = 158 problem drinkers) were assigned to receive either daily or targeted naltrexone 50 mg (n = 81) or matching placebo (n = 77). Patients reported by telephone each evening their current desire to drink and their drinking during the previous night and during the reporting day. We examined genotype, medication, desire to drink and their interactions as predictors of nighttime drinks consumed, controlling for drinking earlier in the day. Asp40 carriers showed a stronger positive association between evening desire (deviations from their mean levels) and later night drinking levels than Asn40 homozygotes (P = 0.019). The desire × genotype × medication condition interaction was also significant (P = 0.009), with a significant desire × genotype interaction for the placebo group (P = 0.001) but not for the naltrexone group (P = 0.74). In summary, when the evening level of desire to drink was relatively high, Asp40 allele carriers were at greater risk than Asn40 homozygotes to drink more, which was attenuated by naltrexone. Although average measures across the study were not informative, daily reports helped to demonstrate the moderating effects of genetic variation on the relation between desire to drink and alcohol consumption and the effects of naltrexone on that phenotype.
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Affiliation(s)
- Henry R. Kranzler
- Department of Psychiatry; Treatment Research Center; Perelman School of Medicine of the University of Pennsylvania and VISN 4 MIRECC; Philadelphia; PA; USA
| | - Stephen Armeli
- Department of Psychology; Fairleigh Dickinson University; Teaneck; NJ; USA
| | - Jonathan Covault
- Department of Psychiatry; Alcohol Research Center; University of Connecticut School of Medicine; Farmington; CT; USA
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189
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Ayanwuyi LO, Carvajal F, Lerma-Cabrera JM, Domi E, Björk K, Ubaldi M, Heilig M, Roberto M, Ciccocioppo R, Cippitelli A. Role of a genetic polymorphism in the corticotropin-releasing factor receptor 1 gene in alcohol drinking and seeking behaviors of marchigian sardinian alcohol-preferring rats. Front Psychiatry 2013; 4:23. [PMID: 23630503 PMCID: PMC3624086 DOI: 10.3389/fpsyt.2013.00023] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/27/2013] [Accepted: 04/02/2013] [Indexed: 11/13/2022] Open
Abstract
Marchigian Sardinian alcohol-preferring (msP) rats exhibit innate preference for alcohol, are highly sensitive to stress and stress-induced alcohol seeking. Genetic analysis showed that over-expression of the corticotropin-releasing factor (CRF) system of msP rats is correlated with the presence of two single nucleotide polymorphisms (SNPs) occurring in the promoter region (position -1836 and -2097) of the CRF1 receptor (CRF1-R) gene. Here we examined whether these point mutations were associated to the innate alcohol preference, stress-induced drinking, and seeking. We have recently re-derived the msP rats to obtain two distinct lines carrying the wild type (GG) and the point mutations (AA), respectively. The phenotypic characteristics of these two lines were compared with those of unselected Wistar rats. Both AA and GG rats showed similar patterns of voluntary alcohol intake and preference. Similarly, the pharmacological stressor yohimbine (0.0, 0.625, 1.25, and 2.5 mg/kg) elicited increased operant alcohol self-administration under fixed and progressive ratio reinforcement schedules in all three lines. Following extinction, yohimbine (0.0, 0.625, 1.25, and 2.5 mg/kg) significantly reinstated alcohol seeking in the three groups. However, at the highest dose this effect was no longer evident in AA rats. Treatment with the CRF1-R antagonist antalarmin (0, 5, 10, and 20 mg/kg) significantly reduced alcohol-reinforced lever pressing in the AA line (10 and 20 mg/kg) while a weaker or no effect was observed in the Wistar and the GG group, respectively. Finally, antalarmin significantly reduced yohimbine-induced increase in alcohol drinking in all three groups. In conclusion, these specific SNPs in the CRF1-R gene do not seem to play a primary role in the expression of the msP excessive drinking phenotype or stress-induced drinking but may be associated with a decreased threshold for stress-induced alcohol seeking and an increased sensitivity to the effects of pharmacological blockade of CRF1-R on alcohol drinking.
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Affiliation(s)
- Lydia O Ayanwuyi
- Pharmacology Unit, School of Pharmacy, University of Camerino Camerino, Italy
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190
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Ray LA, Bujarski S, MacKillop J, Courtney KE, Monti PM, Miotto K. Subjective response to alcohol among alcohol-dependent individuals: effects of the μ-opioid receptor (OPRM1) gene and alcoholism severity. Alcohol Clin Exp Res 2012; 37 Suppl 1:E116-24. [PMID: 23240711 DOI: 10.1111/j.1530-0277.2012.01916.x] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2012] [Accepted: 06/10/2012] [Indexed: 12/11/2022]
Abstract
BACKGROUND Subjective response to alcohol has been examined as a marker of alcoholism risk. The A118G single-nucleotide polymorphism (SNP) of the mu-opioid receptor (OPRM1) gene has been previously associated with subjective response to alcohol in heavy drinkers. This study seeks to extend the literature by examining the effect of OPRM1 genotype on responses to alcohol in a sample of alcohol-dependent individuals. A secondary aim of this study is to examine alcoholism severity as a predictor of subjective responses to alcohol. METHODS Nontreatment seeking problem drinkers (n = 295) were assessed in the laboratory for clinical dimensions of alcohol dependence. Following prospective genotyping, 43 alcohol-dependent individuals across the 2 genotype conditions (AA, n = 23 and AG/GG, n = 20) were randomized to 2 intravenous infusion sessions: 1 of alcohol (target breath alcohol concentration = 0.06 g/dl) and 1 of saline. Measures of subjective responses to alcohol were administered in both infusion sessions. RESULTS Alcohol-dependent G-allele carriers reported greater alcohol-induced stimulation, vigor, and positive mood, as compared to A-allele homozygotes. There was no genotype effect on alcohol-induced sedation or craving. There was a statistical trend-level severity × alcohol interaction such that individuals at higher levels of severity reported greater alcohol-induced tension reduction. CONCLUSIONS These results support the hypothesis that OPRM1 genotype moderates the hedonic effects of alcohol, but not the sedative and unpleasant effects of alcohol, in a sample of alcohol-dependent patients. Results are discussed in light of a clinical neuroscience framework to alcoholism.
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Affiliation(s)
- Lara A Ray
- Department of Psychology, University of California, Los Angeles, Los Angeles, California 90095-1563, USA.
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191
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Abstract
This paper is the thirty-fourth consecutive installment of the annual review of research concerning the endogenous opioid system. It summarizes papers published during 2011 that studied the behavioral effects of molecular, pharmacological and genetic manipulation of opioid peptides, opioid receptors, opioid agonists and opioid antagonists. The particular topics that continue to be covered include the molecular-biochemical effects and neurochemical localization studies of endogenous opioids and their receptors related to behavior (Section 2), and the roles of these opioid peptides and receptors in pain and analgesia (Section 3); stress and social status (Section 4); tolerance and dependence (Section 5); learning and memory (Section 6); eating and drinking (Section 7); alcohol and drugs of abuse (Section 8); sexual activity and hormones, pregnancy, development and endocrinology (Section 9); mental illness and mood (Section 10); seizures and neurologic disorders (Section 11); electrical-related activity and neurophysiology (Section 12); general activity and locomotion (Section 13); gastrointestinal, renal and hepatic functions (Section 14); cardiovascular responses (Section 15); respiration (Section 16); and immunological responses (Section 17).
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Affiliation(s)
- Richard J Bodnar
- Department of Psychology and Neuropsychology Doctoral Sub-Program, Queens College, City University of New York, Flushing, NY 11367, United States.
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192
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OPRM1 and diagnosis-related posttraumatic stress disorder in binge-drinking patients living with HIV. AIDS Behav 2012; 16:2171-80. [PMID: 22143634 DOI: 10.1007/s10461-011-0095-8] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Posttraumatic stress disorder (PTSD) has been linked to numerous negative outcomes in persons living with HIV (PLH) and there is evidence that PTSD symptoms may play a role in maintaining alcohol use problems. The opioid receptor mu-1 (OPRM1) gene may play a role in both PTSD and alcohol use. We examined the association between PTSD and drinking motives as well as variation in the OPRM1 as a predictor of both PTSD and drinking motives in a sample of 201 PLH reporting recent binge drinking. Self-reported PTSD symptom severity was significantly associated with drinking motives for coping, enhancement, and socialization. OPRM1 variation was associated with decreased PTSD symptom severity as well as enhancement motives for drinking.
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193
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Kreek MJ, Levran O, Reed B, Schlussman SD, Zhou Y, Butelman ER. Opiate addiction and cocaine addiction: underlying molecular neurobiology and genetics. J Clin Invest 2012; 122:3387-93. [PMID: 23023708 DOI: 10.1172/jci60390] [Citation(s) in RCA: 142] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Addictive diseases, including addiction to heroin, prescription opioids, or cocaine, pose massive personal and public health costs. Addictions are chronic relapsing diseases of the brain caused by drug-induced direct effects and persisting neuroadaptations at the epigenetic, mRNA, neuropeptide, neurotransmitter, or protein levels. These neuroadaptations, which can be specific to drug type, and their resultant behaviors are modified by various internal and external environmental factors, including stress responsivity, addict mindset, and social setting. Specific gene variants, including variants encoding pharmacological target proteins or genes mediating neuroadaptations, also modify vulnerability at particular stages of addiction. Greater understanding of these interacting factors through laboratory-based and translational studies have the potential to optimize early interventions for the therapy of chronic addictive diseases and to reduce the burden of relapse. Here, we review the molecular neurobiology and genetics of opiate addiction, including heroin and prescription opioids, and cocaine addiction.
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Affiliation(s)
- Mary Jeanne Kreek
- Laboratory of the Biology of Addictive Diseases, The Rockefeller University, New York, New York 10065, USA.
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194
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Alcohol dependence as a chronic pain disorder. Neurosci Biobehav Rev 2012; 36:2179-92. [PMID: 22975446 DOI: 10.1016/j.neubiorev.2012.07.010] [Citation(s) in RCA: 222] [Impact Index Per Article: 18.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2012] [Revised: 06/18/2012] [Accepted: 07/16/2012] [Indexed: 01/22/2023]
Abstract
Dysregulation of pain neurocircuitry and neurochemistry has been increasingly recognized as playing a critical role in a diverse spectrum of diseases including migraine, fibromyalgia, depression, and PTSD. Evidence presented here supports the hypothesis that alcohol dependence is among the pathologies arising from aberrant neurobiological substrates of pain. In this review, we explore the possible influence of alcohol analgesia and hyperalgesia in promoting alcohol misuse and dependence. We examine evidence that neuroanatomical sites involved in the negative emotional states of alcohol dependence also play an important role in pain transmission and may be functionally altered under chronic pain conditions. We also consider possible genetic links between pain transmission and alcohol dependence. We propose an allostatic load model in which episodes of alcohol intoxication and withdrawal, traumatic stressors, and injury are each capable of dysregulating an overlapping set of neural substrates to engender sensory and affective pain states that are integral to alcohol dependence and comorbid conditions such as anxiety, depression, and chronic pain.
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195
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196
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Oertel BG, Doehring A, Roskam B, Kettner M, Hackmann N, Ferreirós N, Schmidt PH, Lötsch J. Genetic-epigenetic interaction modulates μ-opioid receptor regulation. Hum Mol Genet 2012; 21:4751-60. [PMID: 22875838 DOI: 10.1093/hmg/dds314] [Citation(s) in RCA: 88] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Genetic and epigenetic mechanisms play important roles in protein expression, although at different levels. Genetic variations can alter CpG sites and thus influence the epigenetic regulation of mRNA expression, providing an increasingly recognized mechanism of functional consequences of genetic polymorphisms. One of those genetic effects is the association of reduced μ-opioid receptor expression with the functional genetic variant N40D (OPRM1 118A>G, rs1799971) that causes an amino acid exchange in the extracellular terminal of the μ-opioid receptor. We report that the nucleotide exchange at gene position +118 introduces a new CpG-methylation site into the OPRM1 DNA at position +117. This leads to an enhanced methylation of the OPRM1 DNA at this site and downstream. This epigenetic mechanism impedes μ-opioid receptor upregulation in brain tissue of Caucasian chronic opiate addicts, assessed postmortem. While in wild-type subjects, a reduced signalling efficiency associated with chronic heroin exposure was compensated by an increased receptor density, this upregulation was absent in carriers of the 118G receptor variant due to a diminished OPRM1 mRNA transcription. Thus, the OPRM1 118A>G SNP variant not only reduces µ-opioid receptor signalling efficiency, but, by a genetic-epigenetic interaction, reduces opioid receptor expression and therefore, depletes the opioid system of a compensatory reaction to chronic exposure. This demonstrates that a change in the genotype can cause a change in the epigenotype with major functional consequences.
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Affiliation(s)
- Bruno G Oertel
- Institute of Clinical Pharmacology, Goethe-University, Frankfurt am Main, Germany
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197
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Tobacco smoking produces greater striatal dopamine release in G-allele carriers with mu opioid receptor A118G polymorphism. Prog Neuropsychopharmacol Biol Psychiatry 2012; 38:236-40. [PMID: 22516252 DOI: 10.1016/j.pnpbp.2012.04.003] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/26/2012] [Revised: 03/27/2012] [Accepted: 04/03/2012] [Indexed: 11/24/2022]
Abstract
OBJECTIVE To determine if carriers of the allelic expression of the G variant of the human mu opioid receptor (OPRM1) A118G polymorphism have greater increases in striatal dopamine (DA) release after tobacco smoking. METHODS Nineteen of 20 genotyped male tobacco smokers, after overnight abstinence, smoked denicotinized (denic) and average nicotine (nic) containing tobacco cigarettes in a PET brain imaging study using [(11)C]raclopride. RESULTS The right striatum had more free D(2) receptors than the left striatum pre- and post-tobacco smoking. After smoking the nic cigarettes, mean decreased DA binding was observed in the left dorsal caudate (-14 6 11; t=3.77), left and right ventral putamen (-26 3-8; t=4.27; 28 2 1; t=4.25, respectively), and right caudate (17 18 1; t=3.92). The effects of A118G genotype on the binding potentials for these four regions were then analyzed. Carriers of the G allele had larger magnitudes of DA release in response to nic smoking than those homozygous for the more prevalent AA allele in the right caudate and right ventral pallidum (t=3.03; p=0.008 and t=3.91; p=0.001). A voxel by voxel whole brain SPM analysis using an independent samples t test did not reveal any other differences between genotype groups. In addition, the venous plasma cortisol levels of the volunteers from 8:30 a.m. to 12:40 p.m. were lower in the AG/GG allele carriers. Nic smoking increased plasma cortisol in both groups, but they were higher in the AA group. CONCLUSION This preliminary study indicates a difference in both brain striatal DA release and plasma cortisol in A118G polymorphic male tobacco smokers.
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198
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A118G Mu Opioid Receptor polymorphism increases inhibitory effects on CaV2.2 channels. Neurosci Lett 2012; 523:190-4. [PMID: 22796651 DOI: 10.1016/j.neulet.2012.06.074] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2012] [Revised: 06/21/2012] [Accepted: 06/29/2012] [Indexed: 01/22/2023]
Abstract
Single nucleotide polymorphisms (SNPs) in the human OPRM1 gene result in common variants of Mu Opioid Receptors (hMORs). The A118G SNP occurs at high frequency in certain human populations and produces an aminoacidic substitution: N40D (hMOR-N to hMOR-D) at protein level. N40D is reported to alter pain thresholds and morphine efficacy. hMORs inhibit Ca(V)2.2 channels (N-type currents) at presynaptic nociceptor terminals in dorsal horn, thus reducing calcium influx, transmitter release, and transmission of noxious signals. Nociceptors express different splice isoforms of Ca(V)2.2. Isoforms distinguished by the presence of alternatively spliced exon e37a are of interest because channels containing e37a are particularly enriched in nociceptors. Recent studies showed that Ca(V)2.2e37a is more sensitive to inhibition by Mu Opioid Receptors than the ubiquitous splice variant Ca(V)2.2e37b. Here, we evaluate the effect of hMOR-N and hMOR-D on cloned Ca(V)2.2e37a channels expressed in mammalian cells. We observe that hMOR-D inhibits Ca(V)2.2e37a currents at agonist concentrations 4-fold lower than those needed to inhibit Ca(V)2.2e37a currents by the same degree via hMOR-N. We observe little difference in hMOR-D and hMOR-N inhibition of Ca(V)2.2e37b currents. Our study demonstrates that this common site of OPRM1 polymorphism affects the inhibitory actions of MORs on both major Ca(V)2.2 isoforms expressed in nociceptors.
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199
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Ray LA, Courtney KE, Bujarski S, Squeglia LM. Pharmacogenetics of alcoholism: a clinical neuroscience perspective. Pharmacogenomics 2012; 13:129-32. [PMID: 22256863 DOI: 10.2217/pgs.11.173] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
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200
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Setiawan E, Pihl RO, Benkelfat C, Leyton M. Influence of the OPRM1 A118G polymorphism on alcohol-induced euphoria, risk for alcoholism and the clinical efficacy of naltrexone. Pharmacogenomics 2012; 13:1161-72. [DOI: 10.2217/pgs.12.99] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Alcohol-use disorders are thought to be heterogeneous in etiology, pathophysiology and response to treatment. One hypothesized contributor to this variability is the common A118G polymorphism of the µ-opioid receptor gene, OPRM1. This article critically evaluates the evidence that the A118G substitution affects subjective, behavioral and neurobiological responses to alcohol and the opioid receptor antagonist, naltrexone. Although screening of patients in a clinical setting remains premature, results suggest the A118G substitution may influence one etiological pathway to alcoholism, for which naltrexone pharmacotherapy is more effective.
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Affiliation(s)
- Elaine Setiawan
- Department of Neurology & Neurosurgery, McGill University, Montreal, Quebec, Canada
| | - Robert O Pihl
- Department of Psychology, McGill University, Montreal, Quebec, Canada
- Department of Psychiatry, McGill University, Montreal, Quebec, H3A 1A1, Canada
| | - Chawki Benkelfat
- Department of Neurology & Neurosurgery, McGill University, Montreal, Quebec, Canada
- Department of Psychiatry, McGill University, Montreal, Quebec, H3A 1A1, Canada
| | - Marco Leyton
- Department of Neurology & Neurosurgery, McGill University, Montreal, Quebec, Canada
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