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Uusi-Oukari M, Korpi ER. GABAergic mechanisms in alcohol dependence. INTERNATIONAL REVIEW OF NEUROBIOLOGY 2024; 175:75-123. [PMID: 38555121 DOI: 10.1016/bs.irn.2024.03.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/02/2024]
Abstract
The target of alcohol's effect on the central nervous system has been sought for more than 50 years in the brain's GABA system. The behavioral and emotional effects of alcohol in humans and rodents are very similar to those of barbiturates and benzodiazepines, and GABAA receptors have been shown to be one of the sites of alcohol action. The mechanisms of GABAergic inhibition have been a hotspot of research but have turned out to be complex and controversial. Genetics support the involvement of some GABAA receptor subunits in the development of alcohol dependence and in alcohol use disorders (AUD). Since the effect of alcohol on the GABAA system resembles that of a GABAergic positive modulator, it may be possible to develop GABAergic drug treatments that could substitute for alcohol. The adaptation mechanisms of the GABA system and the plasticity of the brain are a big challenge for drug development: the drugs that act on GABAA receptors developed so far also may cause adaptation and development of additional addiction. Human polymorphisms should be studied further to get insight about how they affect receptor function, expression or other factors to make reasonable predictions/hypotheses about what non-addictive interventions would help in alcohol dependence and AUD.
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Affiliation(s)
- Mikko Uusi-Oukari
- Integrative Physiology and Pharmacology, Institute of Biomedicine, University of Turku, Turku, Finland
| | - Esa R Korpi
- Department of Pharmacology, Faculty of Medicine, University of Helsinki, Helsinki, Finland.
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2
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Bowen MT, George O, Muskiewicz DE, Hall FS. FACTORS CONTRIBUTING TO THE ESCALATION OF ALCOHOL CONSUMPTION. Neurosci Biobehav Rev 2022; 132:730-756. [PMID: 34839930 PMCID: PMC8892842 DOI: 10.1016/j.neubiorev.2021.11.017] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2021] [Revised: 11/05/2021] [Accepted: 11/12/2021] [Indexed: 01/03/2023]
Abstract
Understanding factors that contribute to the escalation of alcohol consumption is key to understanding how an individual transitions from non/social drinking to AUD and to providing better treatment. In this review, we discuss how the way ethanol is consumed as well as individual and environmental factors contribute to the escalation of ethanol consumption from intermittent low levels to consistently high levels. Moreover, we discuss how these factors are modelled in animals. It is clear a vast array of complex, interacting factors influence changes in alcohol consumption. Some of these factors act early in the acquisition of ethanol consumption and initial escalation, while others contribute to escalation of ethanol consumption at a later stage and are involved in the development of alcohol dependence. There is considerable need for more studies examining escalation associated with the formation of dependence and other hallmark features of AUD, especially studies examining mechanisms, as it is of considerable relevance to understanding and treating AUD.
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Affiliation(s)
- Michael T. Bowen
- The University of Sydney, Brain and Mind Centre, Sydney, NSW, 2050, Australia,The University of Sydney, Faculty of Science, School of Psychology, Sydney, NSW, 2006, Australia,Corresponding Author: Michael T. Bowen, Brain and Mind Centre, The University of Sydney, 94 Mallett Street, Camperdown, Sydney, NSW, 2050, Australia,
| | - Olivier George
- Department of Psychology, University of California, San Diego, School of Medicine, La Jolla, CA, 92093, USA
| | - Dawn E. Muskiewicz
- Department of Pharmacology & Experimental Therapeutics, College of Pharmacology and Pharmacological Science, University of Toledo, OH, USA
| | - F. Scott Hall
- Department of Pharmacology & Experimental Therapeutics, College of Pharmacology and Pharmacological Science, University of Toledo, OH, USA
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Belelli D, Hales TG, Lambert JJ, Luscher B, Olsen R, Peters JA, Rudolph U, Sieghart W. GABA A receptors in GtoPdb v.2021.3. IUPHAR/BPS GUIDE TO PHARMACOLOGY CITE 2021; 2021. [PMID: 35005623 DOI: 10.2218/gtopdb/f72/2021.3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
The GABAA receptor is a ligand-gated ion channel of the Cys-loop family that includes the nicotinic acetylcholine, 5-HT3 and strychnine-sensitive glycine receptors. GABAA receptor-mediated inhibition within the CNS occurs by fast synaptic transmission, sustained tonic inhibition and temporally intermediate events that have been termed 'GABAA, slow' [45]. GABAA receptors exist as pentamers of 4TM subunits that form an intrinsic anion selective channel. Sequences of six α, three β, three γ, one δ, three ρ, one ε, one π and one θ GABAA receptor subunits have been reported in mammals [278, 235, 236, 283]. The π-subunit is restricted to reproductive tissue. Alternatively spliced versions of many subunits exist (e.g. α4- and α6- (both not functional) α5-, β2-, β3- and γ2), along with RNA editing of the α3 subunit [71]. The three ρ-subunits, (ρ1-3) function as either homo- or hetero-oligomeric assemblies [359, 50]. Receptors formed from ρ-subunits, because of their distinctive pharmacology that includes insensitivity to bicuculline, benzodiazepines and barbiturates, have sometimes been termed GABAC receptors [359], but they are classified as GABA A receptors by NC-IUPHAR on the basis of structural and functional criteria [16, 235, 236]. Many GABAA receptor subtypes contain α-, β- and γ-subunits with the likely stoichiometry 2α.2β.1γ [168, 235]. It is thought that the majority of GABAA receptors harbour a single type of α- and β - subunit variant. The α1β2γ2 hetero-oligomer constitutes the largest population of GABAA receptors in the CNS, followed by the α2β3γ2 and α3β3γ2 isoforms. Receptors that incorporate the α4- α5-or α 6-subunit, or the β1-, γ1-, γ3-, δ-, ε- and θ-subunits, are less numerous, but they may nonetheless serve important functions. For example, extrasynaptically located receptors that contain α6- and δ-subunits in cerebellar granule cells, or an α4- and δ-subunit in dentate gyrus granule cells and thalamic neurones, mediate a tonic current that is important for neuronal excitability in response to ambient concentrations of GABA [209, 272, 83, 19, 288]. GABA binding occurs at the β+/α- subunit interface and the homologous γ+/α- subunits interface creates the benzodiazepine site. A second site for benzodiazepine binding has recently been postulated to occur at the α+/β- interface ([254]; reviewed by [282]). The particular α-and γ-subunit isoforms exhibit marked effects on recognition and/or efficacy at the benzodiazepine site. Thus, receptors incorporating either α4- or α6-subunits are not recognised by 'classical' benzodiazepines, such as flunitrazepam (but see [356]). The trafficking, cell surface expression, internalisation and function of GABAA receptors and their subunits are discussed in detail in several recent reviews [52, 140, 188, 316] but one point worthy of note is that receptors incorporating the γ2 subunit (except when associated with α5) cluster at the postsynaptic membrane (but may distribute dynamically between synaptic and extrasynaptic locations), whereas as those incorporating the δ subunit appear to be exclusively extrasynaptic. NC-IUPHAR [16, 235, 3, 2] class the GABAA receptors according to their subunit structure, pharmacology and receptor function. Currently, eleven native GABAA receptors are classed as conclusively identified (i.e., α1β2γ2, α1βγ2, α3βγ2, α4βγ2, α4β2δ, α4β3δ, α5βγ2, α6βγ2, α6β2δ, α6β3δ and ρ) with further receptor isoforms occurring with high probability, or only tentatively [235, 236]. It is beyond the scope of this Guide to discuss the pharmacology of individual GABAA receptor isoforms in detail; such information can be gleaned in the reviews [16, 95, 168, 173, 143, 278, 216, 235, 236] and [9, 10]. Agents that discriminate between α-subunit isoforms are noted in the table and additional agents that demonstrate selectivity between receptor isoforms, for example via β-subunit selectivity, are indicated in the text below. The distinctive agonist and antagonist pharmacology of ρ receptors is summarised in the table and additional aspects are reviewed in [359, 50, 145, 223]. Several high-resolution cryo-electron microscopy structures have been described in which the full-length human α1β3γ2L GABAA receptor in lipid nanodiscs is bound to the channel-blocker picrotoxin, the competitive antagonist bicuculline, the agonist GABA (γ-aminobutyric acid), and the classical benzodiazepines alprazolam and diazepam [198].
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Berey BL, Leeman RF, Chavarria J, King AC. Relationships between generalized impulsivity and subjective stimulant and sedative responses following alcohol administration. PSYCHOLOGY OF ADDICTIVE BEHAVIORS 2019; 33:616-625. [PMID: 31497988 DOI: 10.1037/adb0000512] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Impulsivity and subjective response (SR) to alcohol (i.e., individual differences in sensitivity to pharmacologic alcohol effects) are both empirically supported risk factors for alcohol use disorder; however, these constructs have been infrequently studied as related risk factors. The present investigation examined a self-report measure of impulsivity (i.e., the Barratt Impulsiveness Scale, Version 11) in relation to acute alcohol effects (i.e., stimulant and sedative SR). Participants came from 2 cohorts of the Chicago Social Drinking Project. Heavy and light drinkers from Cohort 1 (n = 156) and heavy social drinkers from Cohort 2 (n = 104) were examined using identical laboratory protocols following oral alcohol administration using a within-subject, double-blind, placebo-controlled laboratory study design. Self-reported impulsivity and, for comparison purposes, sensation seeking were measured at baseline, and SR was measured once prior to and 4 times following alcohol administration. More impulsive light, but not heavy, drinkers reported heightened stimulant SR following alcohol administration. High impulsive, light drinkers reported stimulant SR at a magnitude similar to that for heavy drinkers, whereas low impulsive, light drinkers reported limited stimulant SR. The interaction between impulsivity and sensation seeking did not statistically predict stimulant SR, and overall, impulsivity was a stronger predictor than was sensation seeking. However, impulsivity was not statistically predictive of dampened sedative SR among light or heavy drinkers. These findings partially replicate and extend the recent literature linking self-reported impulsivity to heightened stimulant SR from alcohol. Future directions include longitudinal studies and research relating multiple facets of impulsivity to SR. (PsycINFO Database Record (c) 2019 APA, all rights reserved).
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Affiliation(s)
- Benjamin L Berey
- Department of Health Education and Behavior, University of Florida
| | - Robert F Leeman
- Department of Health Education and Behavior, University of Florida
| | - Jesus Chavarria
- Department of Psychiatry and Behavioral Neuroscience, University of Chicago
| | - Andrea C King
- Department of Psychiatry and Behavioral Neuroscience, University of Chicago
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5
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Schacht JP, Anton RF, McNamara PJ, Im Y, King AC. The dopamine transporter VNTR polymorphism moderates the relationship between acute response to alcohol and future alcohol use disorder symptoms. Addict Biol 2019; 24:1109-1118. [PMID: 30230123 DOI: 10.1111/adb.12676] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2018] [Revised: 07/23/2018] [Accepted: 07/27/2018] [Indexed: 12/19/2022]
Abstract
Alcohol use disorder (AUD) is a genetically influenced disease with peak onset in young adulthood. Identification of factors that predict whether AUD symptoms will diminish or persist after young adulthood is a critical public health need. King and colleagues previously reported that acute response to alcohol predicted future AUD symptom trajectory. Genes associated with brain dopamine signaling, which underlies alcohol's rewarding effects, might influence this finding. This study analyzed whether variation at a variable number tandem repeat polymorphism in DAT1/SLC6A3, the gene encoding the dopamine transporter, moderated the predictive relationships between acute response to alcohol and future AUD symptoms among participants enrolled in the Chicago Social Drinking Project (first two cohorts). Heavy-drinking young adults (N = 197) completed an alcohol challenge, in which acute response (liking, wanting, stimulation, and sedation) was measured. Alcohol use disorder symptoms were assessed over the following 6 years. DAT1 genotype significantly moderated the interactions between follow-up time and alcohol liking (P = 0.006) and wanting (P = 0.006) in predicting future AUD symptoms. These predictive effects were strongest among participants who carried the DAT1 9-repeat allele, previously associated with enhanced striatal dopamine tone relative to the 10-repeat allele. Exploratory analyses indicated that DAT1 effects on the relationship between alcohol liking and AUD symptoms appeared stronger for females (n = 79) than males (n = 118) (P = 0.0496). These data suggest that heavy-drinking DAT1 9-repeat allele carriers who display high alcohol-induced reward in young adulthood may be predisposed to persistent AUD symptoms and support combining genotypic and phenotypic information to predict future AUD risk.
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Affiliation(s)
- Joseph P. Schacht
- Department of Psychiatry and Behavioral Sciences; Medical University of South Carolina; Charleston South Carolina USA
| | - Raymond F. Anton
- Department of Psychiatry and Behavioral Sciences; Medical University of South Carolina; Charleston South Carolina USA
| | - Patrick J. McNamara
- Department of Psychiatry and Behavioral Neuroscience; University of Chicago; Chicago Illinois USA
| | - Yeongbin Im
- Department of Psychiatry and Behavioral Sciences; Medical University of South Carolina; Charleston South Carolina USA
| | - Andrea C. King
- Department of Psychiatry and Behavioral Neuroscience; University of Chicago; Chicago Illinois USA
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Mulligan MK, Abreo T, Neuner SM, Parks C, Watkins CE, Houseal MT, Shapaker TM, Hook M, Tan H, Wang X, Ingels J, Peng J, Lu L, Kaczorowski CC, Bryant CD, Homanics GE, Williams RW. Identification of a Functional Non-coding Variant in the GABA A Receptor α2 Subunit of the C57BL/6J Mouse Reference Genome: Major Implications for Neuroscience Research. Front Genet 2019; 10:188. [PMID: 30984232 PMCID: PMC6449455 DOI: 10.3389/fgene.2019.00188] [Citation(s) in RCA: 46] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2019] [Accepted: 02/21/2019] [Indexed: 12/16/2022] Open
Abstract
GABA type-A (GABA-A) receptors containing the α2 subunit (GABRA2) are expressed in most brain regions and are critical in modulating inhibitory synaptic function. Genetic variation at the GABRA2 locus has been implicated in epilepsy, affective and psychiatric disorders, alcoholism and drug abuse. Gabra2 expression varies as a function of genotype and is modulated by sequence variants in several brain structures and populations, including F2 crosses originating from C57BL/6J (B6J) and the BXD recombinant inbred family derived from B6J and DBA/2J. Here we demonstrate a global reduction of GABRA2 brain protein and mRNA in the B6J strain relative to other inbred strains, and identify and validate the causal mutation in B6J. The mutation is a single base pair deletion located in an intron adjacent to a splice acceptor site that only occurs in the B6J reference genome. The deletion became fixed in B6J between 1976 and 1991 and is now pervasive in many engineered lines, BXD strains generated after 1991, the Collaborative Cross, and the majority of consomic lines. Repair of the deletion using CRISPR-Cas9-mediated gene editing on a B6J genetic background completely restored brain levels of GABRA2 protein and mRNA. Comparison of transcript expression in hippocampus, cortex, and striatum between B6J and repaired genotypes revealed alterations in GABA-A receptor subunit expression, especially in striatum. These results suggest that naturally occurring variation in GABRA2 levels between B6J and other substrains or inbred strains may also explain strain differences in anxiety-like or alcohol and drug response traits related to striatal function. Characterization of the B6J private mutation in the Gabra2 gene is of critical importance to molecular genetic studies in neurobiological research because this strain is widely used to generate genetically engineered mice and murine genetic populations, and is the most widely utilized strain for evaluation of anxiety-like, depression-like, pain, epilepsy, and drug response traits that may be partly modulated by GABRA2 function.
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Affiliation(s)
- Megan K Mulligan
- Department of Genetics, Genomics and Informatics, University of Tennessee Health Science Center, Memphis, TN, United States
| | - Timothy Abreo
- Department of Genetics, Genomics and Informatics, University of Tennessee Health Science Center, Memphis, TN, United States
| | - Sarah M Neuner
- Department of Anatomy and Neurobiology, University of Tennessee Health Science Center, Memphis, TN, United States.,The Jackson Laboratory, Bar Harbor, ME, United States
| | - Cory Parks
- Department of Genetics, Genomics and Informatics, University of Tennessee Health Science Center, Memphis, TN, United States
| | - Christine E Watkins
- Department of Genetics, Genomics and Informatics, University of Tennessee Health Science Center, Memphis, TN, United States
| | - M Trevor Houseal
- Department of Genetics, Genomics and Informatics, University of Tennessee Health Science Center, Memphis, TN, United States
| | - Thomas M Shapaker
- Department of Genetics, Genomics and Informatics, University of Tennessee Health Science Center, Memphis, TN, United States
| | - Michael Hook
- Department of Genetics, Genomics and Informatics, University of Tennessee Health Science Center, Memphis, TN, United States
| | - Haiyan Tan
- Departments of Structural Biology and Developmental Neurobiology, Center for Proteomics and Metabolomics, St. Jude Children's Research Hospital, Memphis, TN, United States
| | - Xusheng Wang
- Departments of Structural Biology and Developmental Neurobiology, Center for Proteomics and Metabolomics, St. Jude Children's Research Hospital, Memphis, TN, United States
| | - Jesse Ingels
- Department of Genetics, Genomics and Informatics, University of Tennessee Health Science Center, Memphis, TN, United States
| | - Junmin Peng
- Departments of Structural Biology and Developmental Neurobiology, Center for Proteomics and Metabolomics, St. Jude Children's Research Hospital, Memphis, TN, United States
| | - Lu Lu
- Department of Genetics, Genomics and Informatics, University of Tennessee Health Science Center, Memphis, TN, United States
| | | | - Camron D Bryant
- Laboratory of Addiction Genetics, Department of Pharmacology and Experimental Therapeutics and Psychiatry, Boston University School of Medicine, Boston, MA, United States
| | - Gregg E Homanics
- Departments of Anesthesiology and Perioperative Medicine, Neurobiology, and Pharmacology and Chemical Biology, University of Pittsburgh, Pittsburgh, PA, United States
| | - Robert W Williams
- Department of Genetics, Genomics and Informatics, University of Tennessee Health Science Center, Memphis, TN, United States
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7
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Koulentaki M, Kouroumalis E. GABA A receptor polymorphisms in alcohol use disorder in the GWAS era. Psychopharmacology (Berl) 2018; 235:1845-1865. [PMID: 29721579 DOI: 10.1007/s00213-018-4918-4] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/04/2017] [Accepted: 04/18/2018] [Indexed: 12/11/2022]
Abstract
Alcohol use disorder (AUD) is a chronic, relapsing, neuro-psychiatric illness of high prevalence and with a serious public health impact worldwide. It is complex and polygenic, with a heritability of about 50%, and influenced by environmental causal heterogeneity. Risk factors associated with its etiology have a genetic component. GABA (γ-aminobutyric acid) is a major inhibitory neurotransmitter in mammalian brain. GABAA receptors are believed to mediate some of the physiological and behavioral actions of alcohol. In this critical review, relevant genetic terms and type and methodology of the genetic studies are briefly explained. Postulated candidate genes that encode subunits of GABAA receptors, with all the reported SNPs, are presented. Genetic studies and meta-analyses examining polymorphisms of the GABAA receptor and their association with AUD predisposition are presented. The data are critically examined with reference to recent GWAS studies that failed to show relations between GABAA receptors and AUD. Restrictions and perspectives of the different findings are discussed.
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Affiliation(s)
- Mairi Koulentaki
- Alcohology Research Laboratory, Medical School, University of Crete, 71500, Heraklion, Crete, Greece.,Department of Gastroenterology, University Hospital Heraklion, 71500, Heraklion, Crete, Greece
| | - Elias Kouroumalis
- Department of Gastroenterology, University Hospital Heraklion, 71500, Heraklion, Crete, Greece.
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Schuckit MA. A Critical Review of Methods and Results in the Search for Genetic Contributors to Alcohol Sensitivity. Alcohol Clin Exp Res 2018; 42:822-835. [PMID: 29623680 PMCID: PMC5916326 DOI: 10.1111/acer.13628] [Citation(s) in RCA: 44] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2017] [Accepted: 03/06/2018] [Indexed: 02/06/2023]
Abstract
Attributes of alcohol sensitivity are present before alcohol use disorders (AUDs) develop, they predict those adverse alcohol outcomes, are familial in nature, and many are heritable. Whether measured by alcohol challenges or retrospective reports of numbers of drinks required for effects, alcohol sensitivity reflects multiple phenotypes, including low levels of alcohol response and alcohol-related stimulation. Identification of genes that contribute to alcohol sensitivity could help identify individuals carrying risks for AUDs through their alcohol responses for whom early intervention might mitigate their vulnerability. Such genes could also improve understanding of biological underpinnings of AUDs, which could lead to new treatment approaches. However, the existing literature points to a wide range of genetic mechanisms that might contribute to alcohol responses, and few such genetic findings have been widely replicated. This critical review describes the potential impact of the diverse methods used to study sensitivity on the diversity of genetic findings that have been reported, places the genetic variants mentioned in the literature into broader categories rather than isolated results, and offers suggestions regarding how to advance the field by interpreting findings in light of the methods used to select research subjects and to measure alcohol sensitivity. To date, the most promising results have been for GABA, glutamate, opioid, dopamine, serotonin, and cholinergic system genes. The more gene variants that can be identified as contributors to sensitivity the better future gene screening platforms or polygenic scores are likely to be.
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Affiliation(s)
- Marc A Schuckit
- Department of Psychiatry, University of California, San Diego School of Medicine, La Jolla, California
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Mallard TT, Ashenhurst JR, Harden KP, Fromme K. GABRA2, alcohol, and illicit drug use: An event-level model of genetic risk for polysubstance use. JOURNAL OF ABNORMAL PSYCHOLOGY 2018; 127:190-201. [PMID: 29528673 PMCID: PMC5851473 DOI: 10.1037/abn0000333] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
GABRA2, the gene encoding the α2 subunit of the GABAA receptor, potentially plays a role in the etiology of problematic drinking, as GABRA2 genotype has been associated with subjective response to alcohol and other alcohol-related reward processes. The GABRA2 gene has also been associated with illicit drug use, but the extent to which associations with drug use are independent of associations with alcohol use remains unclear, partly because most previous research has used a cross-sectional design that cannot discriminate comorbidity at the between-person level and co-occurrence within-persons. The present study used a daily monitoring method that assessed the effects of GABRA2 variation on substance use as it occurred in the natural environment during emerging adulthood. Non-Hispanic European participants provided DNA samples and completed daily reports of alcohol and drug use for 1 month per year across 4 years (N = 28,263 unique observations of N = 318 participants). GABRA2 variants were associated with illicit drug use in both sober and intoxicated conditions. Moreover, the effect of GABRA2 variation on drug use was moderated by an individual's degree of intoxication. These findings are consistent with recent genetic and neuroscience research, and they suggest GABRA2 variation influences drug-seeking behavior through both alcohol-related and alcohol-independent pathways. (PsycINFO Database Record
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Affiliation(s)
| | | | - K Paige Harden
- Department of Psychology, The University of Texas at Austin
| | - Kim Fromme
- Department of Psychology, The University of Texas at Austin
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10
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Newton-Howes G, Foulds J. Personality Disorder and Alcohol Use Disorder: An Overview. Psychopathology 2018; 51:130-136. [PMID: 29466805 DOI: 10.1159/000486602] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/13/2017] [Accepted: 12/26/2017] [Indexed: 12/15/2022]
Abstract
BACKGROUND Clinically, personality disorder (PD) commonly coexists with alcohol use disorder (AUD), although within mainstream mental health services both of these mental disorders are routinely overlooked. Despite a rich literature examining the interactions between AUD and personality functioning, personality traits, and PD, there remains conflicting evidence as to the degree of association and impact of one on the other. METHODS A narrative review and a synthesis of the literature were done. RESULTS The lifetime prevalence of AUD approaches 50% in some PD populations. The rates of PD in AUD populations are less clear but likely similar. Personality influences outcomes in AUD regardless of whether a categorical personality diagnosis or dimensional trait domain approach is taken. There are, however, no good data to inform clinicians on the impact of AUD on the outcomes of PD. Understanding the extent of this impact is complicated by the multiple tools used for diagnosis (of both PD and AUD) and the statistical methods used. Overall, caution is required in interpreting the data due to the quality of the current literature; however, comorbidity between the two disorders is likely significant and the impact of PD on AUD outcomes is sufficient to require consideration. CONCLUSIONS From a research perspective, better agreement on both diagnoses and outcomes is urgently needed to improve the overall quality of the evidence. Clinically, despite the limitations in the literature, it is unacceptable for PD services to ignore AUD and for AUD services not to screen for PD. Both are likely to have an impact on health and functioning and should be considered in routine reviews. A better conceptualization of the putative mechanisms of this interaction, as well as an understanding of the neurobiology and reasons for the impact on treatment outcomes, will help to move the field forward.
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Affiliation(s)
- Giles Newton-Howes
- Department of Psychological Medicine, University of Otago, Wellington, New Zealand
| | - James Foulds
- Department of Psychological Medicine, University of Otago, Christchurch, New Zealand
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Yang BZ, Arias A, Feinn R, Krystal JH, Gelernter J, Petrakis I. GRIK1 and GABRA2 Variants Have Distinct Effects on the Dose-Related Subjective Response to Intravenous Alcohol in Healthy Social Drinkers. Alcohol Clin Exp Res 2017; 41:2025-2032. [PMID: 29131352 PMCID: PMC5764175 DOI: 10.1111/acer.13516] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2017] [Accepted: 09/18/2017] [Indexed: 11/27/2022]
Abstract
BACKGROUND The heritable risk for alcohol use disorder (AUD) is expressed partly through alterations in subjective alcohol response. In this study, we investigated the effects of 2 AUD-risk-associated single nucleotide polymorphisms, GABRA2 rs279858 and GRIK1 rs2832407, on the subjective response to alcohol administered intravenously to healthy social drinkers in a laboratory setting. METHODS In total, 93 self-identified European American social drinkers underwent 3 blinded laboratory sessions in which they received intravenous infusions of ethanol at 3 target blood alcohol levels (0.00 mg%, 40 mg%, and 100 mg%) using a "clamp" procedure. The self-reported Biphasic Alcohol Effects Scale (BAES) stimulation and sedation subscales were the primary outcome measures. We examined the effects of these 2 genetic variants on subjective response to alcohol. RESULTS For the BAES stimulation subscale scores, adjusting for age, baseline scores, and time effects, individuals with 2 copies of the GABRA2 rs279858 C "risk" allele for AUD exhibited the greatest stimulant responses to high-dose alcohol compared to the other risk allele counts (dose-by-allele count interaction effect, p = 0.001, post hoc contrast for C-allele, p = 0.012). For the BAES sedation subscale scores, adjusting for the same covariates, we detected a dose-by-allele count interaction effect (p = 0.0044) such that subjects with 2 copies of the GRIK1 C "risk" allele reported the greatest sedative response to the higher alcohol dose. CONCLUSIONS This study suggests that gene variants contributing to the risk for AUD may alter features of the alcohol dose-response relationship in specific ways. GABRA2 rs279858*C enhances stimulant responses to higher levels of alcohol, while the GRIK1 rs2832407*C-allele increases sedative responses. In summary, GRIK1 and GABRA2 variants have distinct effects on the dose-related subjective response to intravenous alcohol in humans.
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Affiliation(s)
- Bao-Zhu Yang
- Department of Psychiatry, Yale University School of MedicineNew Haven, CT
- Department of Veterans Affairs, Alcohol Research Center VA Connecticut Healthcare System (116-A) 950 Campbell Ave West Haven, CT 06516
| | - Albert Arias
- Department of Psychiatry, Yale University School of MedicineNew Haven, CT
- Department of Veterans Affairs, Alcohol Research Center VA Connecticut Healthcare System (116-A) 950 Campbell Ave West Haven, CT 06516
| | | | - John H. Krystal
- Department of Psychiatry, Yale University School of MedicineNew Haven, CT
- Department of Veterans Affairs, Alcohol Research Center VA Connecticut Healthcare System (116-A) 950 Campbell Ave West Haven, CT 06516
| | - Joel Gelernter
- Department of Psychiatry, Yale University School of MedicineNew Haven, CT
- Department of Veterans Affairs, Alcohol Research Center VA Connecticut Healthcare System (116-A) 950 Campbell Ave West Haven, CT 06516
- Departments of Genetics and Neuroscience, Yale University School of Medicine
| | - Ismene Petrakis
- Department of Psychiatry, Yale University School of MedicineNew Haven, CT
- Department of Veterans Affairs, Alcohol Research Center VA Connecticut Healthcare System (116-A) 950 Campbell Ave West Haven, CT 06516
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Wu HZ, Barry LC, Duan Y, Bohannon RW, Covault JM, Grady JJ. Acute Effects of Moderate Alcohol Consumption on Postural Stability in Older Adults. Percept Mot Skills 2017; 124:912-931. [DOI: 10.1177/0031512517721069] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
This study involved healthy community-living older adults in an investigation of the association between moderate alcohol consumption (AC) and acute changes in postural stability and whether the association differed according to pre-AC balance skills. Thirty-nine moderate drinkers aged ≥ 65 years (62% women; mean age: 73.9 ± 6.1 years) consumed a moderate dose of alcohol (0.4 g/kg; administered as two drinks). Breath alcohol concentration and postural stability were measured at five time points (pre-AC and 40, 80, 120, and 160 minutes post-AC) using unipedal stance time (UPST) and center of pressure (CoP) displacement. Pre-AC UPST was used to categorize participants into good-balance (≥30 seconds) and poor-balance (<30 seconds) groups. Peak breath alcohol concentration was 30 mg/dL at 40 minutes post-AC. For all participants, postural stability declined significantly at 80 minutes post-AC (UPST, p = .005; anterior–posterior CoP displacement, p = .029). While the poor-balance group did not show a significant decrease in UPST duration over the course of the study, the good-balance group experienced significant decline at 80 minutes compared with baseline ( p < .001) and remained above the 30-second UPST cutoff. Both groups experienced similar worsening in anterior–posterior CoP displacement at 80 minutes post-AC. Thus, moderate AC was associated with acute decline in postural stability in older adults. The worsened anterior–posterior CoP displacement post-AC in the poor-balance group was of particular concern because these participants were already at lower balance functioning pre-AC. Larger, more representative studies of varying groups of participants are needed to further explore how this change relates to fall incidents and fall risk.
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Affiliation(s)
- Helen Z. Wu
- Department of Psychiatry, University of Connecticut Health Center, Farmington, CT, USA
- Connecticut Institute for Clinical and Translational Science (CICATS), Farmington, CT, USA
| | - Lisa C. Barry
- Department of Psychiatry, University of Connecticut Health Center, Farmington, CT, USA
- Center on Aging, University of Connecticut Heath Center, Farmington, CT, USA
| | - Yinghui Duan
- Department of Community Medicine and Health Care, University of Connecticut Health Center, Farmington, CT, USA
- Connecticut Institute for Clinical and Translational Science (CICATS), Farmington, CT, USA
| | - Richard W. Bohannon
- Department of Physical Therapy, College of Pharmacy and Health Sciences, Campbell University, Lillington, NC, USA
| | - Jonathan M. Covault
- Department of Psychiatry, University of Connecticut Health Center, Farmington, CT, USA
| | - James J. Grady
- Department of Community Medicine and Health Care, University of Connecticut Health Center, Farmington, CT, USA
- Connecticut Institute for Clinical and Translational Science (CICATS), Farmington, CT, USA
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Fine Mapping of a Dravet Syndrome Modifier Locus on Mouse Chromosome 5 and Candidate Gene Analysis by RNA-Seq. PLoS Genet 2016; 12:e1006398. [PMID: 27768696 PMCID: PMC5074504 DOI: 10.1371/journal.pgen.1006398] [Citation(s) in RCA: 60] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2016] [Accepted: 10/03/2016] [Indexed: 12/19/2022] Open
Abstract
A substantial number of mutations have been identified in voltage-gated sodium channel genes that result in various forms of human epilepsy. SCN1A mutations result in a spectrum of severity ranging from mild febrile seizures to Dravet syndrome, an infant-onset epileptic encephalopathy. Dravet syndrome patients experience multiple seizures types that are often refractory to treatment, developmental delays, and elevated risk for SUDEP. The same sodium channel mutation can produce epilepsy phenotypes of varying clinical severity. This suggests that other factors, including genetic, modify the primary mutation and change disease severity. Mouse models provide a useful tool in studying the genetic basis of epilepsy. The mouse strain background can alter phenotype severity, supporting a contribution of genetic modifiers in epilepsy. The Scn1a+/- mouse model has a strain-dependent epilepsy phenotype. Scn1a+/- mice on the 129S6/SvEvTac (129) strain have a normal phenotype and lifespan, while [129xC57BL/6J]F1-Scn1a+/- mice experience spontaneous seizures, hyperthermia-induced seizures and high rates of premature death. We hypothesize the phenotypic differences are due to strain-specific genetic modifiers that influence expressivity of the Scn1a+/- phenotype. Low resolution mapping of Scn1a+/- identified several Dravet syndrome modifier (Dsm) loci responsible for the strain-dependent difference in survival. One locus of interest, Dsm1 located on chromosome 5, was fine mapped to a 9 Mb region using interval specific congenics. RNA-Seq was then utilized to identify candidate modifier genes within this narrowed region. Three genes with significant total gene expression differences between 129S6/SvEvTac and [129xC57BL/6J]F1 were identified, including the GABAA receptor subunit, Gabra2. Further analysis of Gabra2 demonstrated allele-specific expression. Pharmological manipulation by clobazam, a common anticonvulsant with preferential affinity for the GABRA2 receptor, revealed dose-dependent protection against hyperthermia-induced seizures in Scn1a+/- mice. These findings support Gabra2 as a genetic modifier of the Scn1a+/- mouse model of Dravet syndrome. Epilepsy is a neurological disorder affecting approximately 3 million Americans and 1% of the worldwide population. Approximately 70% of patients diagnosed with epilepsy have a genetic basis for their disease. The same genetic mutation can result in epilepsy with varying clinical severity in some individuals. This suggests that additional factors modify the effect of the primary mutation, resulting in the differences observed. Mouse models of epilepsy also exhibit variable severity depending on the inbred strain background. This is a useful model system that enables us to determine other genetic factors that influence phenotype presentation. This study investigates a mouse model of Dravet syndrome. Similar to Dravet syndrome patients, the mice experience a variety of seizure types and have increased risk for premature death. Interestingly, the Dravet syndrome phenotype is completely masked on one mouse strain background. Through a series of genetic and pharmacological techniques we were able to identify a gene that is likely responsible for the strain-dependent phenotype difference of Dravet mice. Identifying genes that modify diseases can help predict patient outcomes and suggest new therapies for the treatment of epilepsy.
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Stephens DN, King SL, Lambert JJ, Belelli D, Duka T. GABAAreceptor subtype involvement in addictive behaviour. GENES BRAIN AND BEHAVIOR 2016; 16:149-184. [DOI: 10.1111/gbb.12321] [Citation(s) in RCA: 62] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/31/2016] [Revised: 07/19/2016] [Accepted: 08/15/2016] [Indexed: 12/17/2022]
Affiliation(s)
| | - S. L. King
- School of Psychology; University of Sussex; Brighton UK
| | - J. J. Lambert
- Division of Neuroscience; University of Dundee; Dundee UK
| | - D. Belelli
- Division of Neuroscience; University of Dundee; Dundee UK
| | - T. Duka
- School of Psychology; University of Sussex; Brighton UK
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Beyond risk: Prospective effects of GABA Receptor Subunit Alpha-2 (GABRA2) × Positive Peer Involvement on adolescent behavior. Dev Psychopathol 2016; 29:711-724. [PMID: 27581089 DOI: 10.1017/s0954579416000419] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Research on Gene × Environment interactions typically focuses on maladaptive contexts and outcomes. However, the same genetic factors may also impact susceptibility to positive social contexts, leading to adaptive behavior. This paper examines whether the GABA receptor subunit alpha-2 (GABRA2) single nucleotide polymorphism rs279858 moderates the influence of positive peer affiliation on externalizing behavior and various forms of competence. Regions of significance were calculated to determine whether the form of the interaction supported differential susceptibility (increased sensitivity to both low and high positive peer affiliation) or vantage sensitivity (increased sensitivity to high positive peer affiliation). It was hypothesized that those carrying the homozygous minor allele (GG) would be more susceptible to peer effects. A sample (n = 300) of primarily male (69.7%) and White (93.0%) adolescents from the Michigan Longitudinal Study was assessed from ages 12 to 17. There was evidence for prospective Gene × Environment interactions in three of the four models. At low levels of positive peer involvement, those with the GG genotype were rated as having fewer adaptive outcomes, while at high levels they were rated as having greater adaptive outcomes. This supports differential susceptibility. Conceptualizing GABRA2 variants as purely risk factors may be inaccurate. Genetic differences in susceptibility to adaptive environmental exposures warrants further investigation.
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Perry BL. Gendering Genetics: Biological Contingencies in the Protective Effects of Social Integration for Men and Women. AJS; AMERICAN JOURNAL OF SOCIOLOGY 2016; 121:1655-1696. [PMID: 27416652 DOI: 10.1086/685486] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Evidence that social and biological processes are intertwined in producing health and human behavior is rapidly accumulating. Using a feminist approach, this research explores how gender moderates the interaction between biological processes and men's and women's behavioral and emotional responses to similar social environments. Using data from the Collaborative Study on the Genetics of Alcoholism, the influence of gender, social integration, and genetic risk on nicotine and alcohol dependence is examined. Three-way interaction models reveal gender-specific moderation of interactions between genetic risk score and social integration. Namely, being currently married and reporting positive social psychological integration are predictive of reduced risk of nicotine dependence among men with genetic susceptibility to strong nicotine cravings in the presence of social cues like stress. In contrast, the protective effects of marital status and social integration are substantially attenuated and absent, respectively, among women with high-risk genotypes. This pattern reflects the dualism (i.e., simultaneous costs and benefits) inherent in social integration for women, which may disproportionately affect those with a genetic sensitivity to stress. These findings contest the notion of genotype as static biological hardwiring that is independent from social and cultural systems of gender difference.
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Boyd SJ, Schacht JP, Prisciandaro JJ, Voronin K, Anton RF. Alcohol-Induced Stimulation Mediates the Effect of a GABRA2 SNP on Alcohol Self-Administrated among Alcohol-Dependent Individuals. Alcohol Alcohol 2016; 51:549-54. [PMID: 27117237 DOI: 10.1093/alcalc/agw024] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2015] [Accepted: 04/05/2016] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND A single-nucleotide polymorphism (SNP) in GABRA2 (rs279858) may moderate subjective response (SR) to alcohol. Results of studies in non-dependent drinkers examining this GABRA2 SNP on SR have been equivocal. This study examined this SNP's direct and indirect effects on alcohol self-administration in dependent drinkers. METHOD The sample consisted of 63 Caucasian, non-treatment-seeking individuals with alcohol dependence. Subjective stimulation was assessed using the Biphasic Alcohol Effects Scale following consumption of an alcoholic priming drink (target breath alcohol content = 0.02 g%). Participants were subsequently offered the opportunity to self-administer up to eight additional drinks. RESULTS Controlling for baseline stimulation, T-allele homozygotes, relative to individuals with at least one copy of the C-allele, reported greater initial stimulation, t(58) = 2.011, p = 0.049. Greater stimulation predicted greater subsequent alcohol self-administration, t(57) = 2.522, p = 0.015. Although rs279858 genotype did not directly impact self-administration (t(57) = -0.674, p = 0.503), it did have an indirect effect (95% confidence interval [0.068, 1.576]), such that T-allele homozygotes reported greater stimulation, which in turn predicted greater self-administration. CONCLUSION These results suggest that the influence of this SNP on SR differs depending on dose or stage of dependence. This study is the first to demonstrate an indirect effect of rs279858 genotype on drinking through SR. Although C-allele carriers have been shown to have an increased risk for alcohol dependence, in our dependent sample, greater stimulation was found among T-allele homozygotes, suggesting that the influence of SR on developing and maintaining dependence differs based on rs279858 genotype.This study demonstrates an indirect effect of rs279858 genotype on drinking through SR. Although C-allele carriers have an increased risk for alcohol dependence, in our dependent sample, greater stimulation was found among T-allele homozygotes, suggesting that the influence of SR on developing dependence differs based on rs279858 genotype.
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Affiliation(s)
- Stephen J Boyd
- Charleston Alcohol Research Center, Department of Psychiatry and Behavioral Sciences, Medical University of South Carolina, Charleston, SC, USA
| | - Joseph P Schacht
- Charleston Alcohol Research Center, Department of Psychiatry and Behavioral Sciences, Medical University of South Carolina, Charleston, SC, USA
| | - James J Prisciandaro
- Charleston Alcohol Research Center, Department of Psychiatry and Behavioral Sciences, Medical University of South Carolina, Charleston, SC, USA
| | - Konstantin Voronin
- Charleston Alcohol Research Center, Department of Psychiatry and Behavioral Sciences, Medical University of South Carolina, Charleston, SC, USA
| | - Raymond F Anton
- Charleston Alcohol Research Center, Department of Psychiatry and Behavioral Sciences, Medical University of South Carolina, Charleston, SC, USA
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Strac DS, Erjavec GN, Perkovic MN, Sviglin KN, Borovecki F, Pivac N. Association of GABAA receptor α2 subunit gene (GABRA2) with alcohol dependence-related aggressive behavior. Prog Neuropsychopharmacol Biol Psychiatry 2015; 63:119-25. [PMID: 26116794 DOI: 10.1016/j.pnpbp.2015.06.010] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/26/2015] [Revised: 06/18/2015] [Accepted: 06/22/2015] [Indexed: 12/12/2022]
Abstract
Alcohol dependence is a common chronic disorder precipitated by the complex interaction between biological, genetic and environmental risk factors. Recent studies have demonstrated that polymorphisms of the gene encoding the GABAA receptor α2 subunit (GABRA2) are associated with alcohol dependence in different populations of European ancestry. As aggression often occurs in the context of alcohol dependence, the aim of this study was to examine the allelic and haplotypic association of GABRA2 gene with alcohol dependence and related aggressive behavior in subjects of Eastern European (Croatian) origin. Genotyping of the 3 single nucleotide polymorphisms (SNPs) across the GABRA2 gene (rs567926, rs279858 and rs9291283) was performed in patients with alcohol dependence (N=654) and healthy control subjects (N=574). Alcohol-dependent participants were additionally subdivided according to the presence/absence of aggressive behavior and type of alcohol dependence according to the Cloninger's classification. The association of rs279858 with alcohol dependence yielded nominal significance level. Haplotype analysis revealed a high degree of linkage disequilibrium (LD) for rs567926 and rs279858, but not for rs9291283 polymorphism in the GABRA2 gene. In patients with alcohol dependence, the A-C (rs567926 and rs279858) haplotype carriers were more likely to demonstrate aggressive behavior. The same haplotype (present only in 1.6% of all subjects) was significantly more often present in patients with a combination of early onset alcohol abuse and aggression, corresponding to the Cloninger's type II alcoholism subgroup. These findings support the involvement of GABRA2 gene in alcohol dependence-related aggressive behavior.
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Affiliation(s)
| | | | | | - Korona Nenadic Sviglin
- Center for Alcoholism and Other Addictions, Psychiatric Hospital Vrapce, Zagreb, Croatia
| | - Fran Borovecki
- Department for Functional Genomics, Center for Translational and Clinical Research, School of Medicine, University of Zagreb, University Hospital Center Zagreb, Zagreb, Croatia
| | - Nela Pivac
- Division of Molecular Medicine, Rudjer Boskovic Institute, Zagreb, Croatia.
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Duka T, Dixon CI, Trick L, Crombag HS, King SL, Stephens DN. Motivational Effects of Methylphenidate are Associated with GABRA2 Variants Conferring Addiction Risk. Front Behav Neurosci 2015; 9:304. [PMID: 26635556 PMCID: PMC4649050 DOI: 10.3389/fnbeh.2015.00304] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2015] [Accepted: 10/29/2015] [Indexed: 12/02/2022] Open
Abstract
Background: Variations in the GABRA2 gene, encoding α2 subunits of GABAA receptors, have been associated with risk for addiction to several drugs, but the mechanisms by which variations in non-coding regions of GABRA2 increase risk for addictions are not understood. Mice with deletion of GABRA2 show deficits in the ability of psychostimulants to facilitate responding for conditioned reinforcers, offering a potential explanation. Methods: We report human and mouse studies investigating a potential endophenotype underlying this association. Healthy human volunteers carrying either cocaine-addiction “risk” or “protective” GABRA2 single nucleotide polymorphism (SNPs) were tested for their subjective responses to methylphenidate, and methylphenidate’s ability to facilitate conditioned reinforcement (CRf) for visual stimuli (CS+) associated with monetary reward. In parallel, methylphenidate’s ability to facilitate responding for a visual CRf was studied in wildtype and α2 knockout (α2−/−) mice. Results: Methylphenidate increased the number of CS+ presentations obtained by human subjects carrying protective, but not risk SNPs. In mice, methylphenidate increased responding for a CS+ in wildtype, but not α2−/− mice. Human subjects carrying protective SNPs felt stimulated, aroused and restless following methylphenidate, while individuals carrying risk SNPs did not. Conclusion: Human risk SNP carriers were insensitive to methylphenidate’s effects on mood or in facilitating CRf. That mice with the gene deletion were also insensitive to methylphenidate’s ability to increase responding for CRf, suggests a potential mechanism whereby low α2-subunit levels increase risk for addictions. Circuits employing GABAA-α2 subunit-containing receptors may protect against risk for addictions.
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Affiliation(s)
- Theodora Duka
- School of Psychology, University of Sussex, Falmer Brighton, UK
| | - Claire I Dixon
- School of Psychology, University of Sussex, Falmer Brighton, UK
| | - Leanne Trick
- School of Psychology, University of Sussex, Falmer Brighton, UK
| | - Hans S Crombag
- School of Psychology, University of Sussex, Falmer Brighton, UK
| | - Sarah L King
- School of Psychology, University of Sussex, Falmer Brighton, UK
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20
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Raud S, Reimets R, Loomets M, Sütt S, Altpere A, Visnapuu T, Innos J, Luuk H, Plaas M, Volke V, Vasar E. Deletion of the Wolfram syndrome-related gene Wfs1 results in increased sensitivity to ethanol in female mice. Neuropharmacology 2015; 95:59-67. [DOI: 10.1016/j.neuropharm.2015.02.019] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2014] [Revised: 02/13/2015] [Accepted: 02/15/2015] [Indexed: 10/23/2022]
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21
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Kosobud AEK, Wetherill L, Plawecki MH, Kareken DA, Liang T, Nurnberger JL, Windisch K, Xuei X, Edenberg HJ, Foroud TM, O'Connor SJ. Adaptation of Subjective Responses to Alcohol is Affected by an Interaction of GABRA2 Genotype and Recent Drinking. Alcohol Clin Exp Res 2015; 39:1148-57. [PMID: 26087834 DOI: 10.1111/acer.12749] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2014] [Accepted: 03/30/2015] [Indexed: 11/28/2022]
Abstract
BACKGROUND Subjective perceptions of alcohol intoxication are associated with altered risk for alcohol abuse and dependence. Acute adaptation of these perceptions may influence such risk and may involve genes associated with pleasant perceptions or the relief of anxiety. This study assessed the effect of variation in the GABAA receptor genes GABRG1 and GABRA2 and recent drinking history on the acute adaptation of subjective responses to alcohol. METHODS One hundred and thirty-two nondependent moderate to heavy drinkers, aged 21 to 27, participated in 2 single-blind, counterbalanced sessions, approximately 1 week apart. One session was an intravenous alcohol "clamp," during which breath alcohol concentration was held steady at 60 mg/dl (60 mg%) for 3 hours, and the other an identical session using saline infusion. Subjective perceptions of Intoxication, Enjoyment, Stimulation, Relaxation, Anxiety, Tiredness, and Estimated Number of Drinks were acquired before (baseline), and during the first and final 45 minutes of the clamp. A placebo-adjusted index of the subject's acute adaptation to alcohol was calculated for each of the 7 subjective measures and used in a principal component analysis to create a single aggregate estimate for each subject's adaptive response to alcohol. Analysis of covariance tested whether GABRA2 and GABRG1 single nucleotide polymorphism (SNP) genotypes, gender, placebo session, family history of alcoholism, recent drinking history, and the genotype × recent drinking history interaction significantly predicted the adaptive response. RESULTS Recent drinking history (p = 0.01), and recent drinking history × genotype interaction (p = 0.01) were significantly associated with acute adaptation of the subjective responses to alcohol for the GABRA2 SNP rs279858. CONCLUSIONS Higher recent drinking was found to be associated with reduced acute tolerance to positive, stimulating effects of alcohol in carriers of the rs279858 risk allele. We postulate that the GABRA2 effect on alcohol dependence may, in part, be due to its effect on subjective responses to alcohol.
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Affiliation(s)
- Ann E K Kosobud
- Department of Neurology, Indiana University School of Medicine, Indianapolis, Indiana
| | - Leah Wetherill
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis, Indiana.,Department of Psychology, Indiana University Purdue University at Indianapolis, Indianapolis, Indiana
| | - Martin H Plawecki
- Department of Psychiatry, Indiana University School of Medicine, Indianapolis, Indiana
| | - David A Kareken
- Department of Neurology, Indiana University School of Medicine, Indianapolis, Indiana
| | - Tiebing Liang
- Department of Medicine, Division of Endocrinology, Indiana University School of Medicine, Indianapolis, Indiana
| | - John L Nurnberger
- Department of Psychiatry, Indiana University School of Medicine, Indianapolis, Indiana
| | - Kyle Windisch
- Department of Psychology, Indiana University Purdue University at Indianapolis, Indianapolis, Indiana
| | - Xiaoling Xuei
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, Indiana
| | - Howard J Edenberg
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis, Indiana.,Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, Indiana
| | - Tatiana M Foroud
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis, Indiana
| | - Sean J O'Connor
- Department of Psychiatry, Indiana University School of Medicine, Indianapolis, Indiana.,R.L. Roudebush Veterans Administration Medical Center, Indianapolis, Indiana
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Jones JD, Comer SD, Kranzler HR. The pharmacogenetics of alcohol use disorder. Alcohol Clin Exp Res 2015; 39:391-402. [PMID: 25703505 PMCID: PMC4348335 DOI: 10.1111/acer.12643] [Citation(s) in RCA: 66] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2014] [Accepted: 11/24/2014] [Indexed: 12/16/2022]
Abstract
BACKGROUND Annually, the use and abuse of alcohol contributes to millions of deaths and billions of dollars in societal costs. To determine the impact of genetic variation on the susceptibility to the disorder and its response to treatment, studies have been conducted to assess the contribution of a variety of candidate genetic variants. These variants, which we review here, were chosen based upon their observed or hypothesized functional relevance to alcohol use disorder (AUD) risk or to the mechanism by which medications used to treat the disorder exert their effects. METHODS This qualitative review examines studies in which candidate polymorphisms were tested as moderator variables to identify pharmacogenetic effects on either the subjective response to alcohol or the outcomes of pharmacotherapy. RESULTS Although findings from these studies provide evidence of a number of clinically relevant pharmacogenetic effects, the literature is limited and there are conflicting findings that require resolution. CONCLUSIONS Pharmacogenetic studies of AUD treatment that use greater methodological rigor and better statistical controls, such as corrections for multiple testing, may help to resolve inconsistent findings. These procedures could also lead to the discovery of more robust and clinically meaningful moderator effects. As the field evolves through methodological standardization and the use of larger study samples, pharmacogenetic research has the potential to inform clinical care by enhancing therapeutic effects and personalizing treatments. These efforts may also provide insights into the mechanisms by which medications reduce heavy drinking or promote abstinence in patients with an AUD.
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Affiliation(s)
- Jermaine D Jones
- Division on Substance Abuse , New York State Psychiatric Institute & Columbia University College of Physicians and Surgeons, New York, New York
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Trucco EM, Villafuerte S, Heitzeg MM, Burmeister M, Zucker RA. Rule breaking mediates the developmental association between GABRA2 and adolescent substance abuse. J Child Psychol Psychiatry 2014; 55:1372-9. [PMID: 24811113 PMCID: PMC4470372 DOI: 10.1111/jcpp.12244] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 03/13/2014] [Indexed: 01/21/2023]
Abstract
BACKGROUND This study's primary aim was to examine age-specific associations between GABRA2, rule breaking, problematic alcohol use, and substance abuse symptomatology. The secondary aim was to examine the extent to which rule breaking mediates the GABRA2-substance abuse relationship. METHODS A sample (n = 518) of primarily male (70.9%) and White (88.8%) adolescents from the Michigan Longitudinal Study was assessed from ages 11-18. Age-specific effects of GABRA2 on rule breaking, problematic alcohol use, and substance abuse symptomatology were examined using nested path models. The role of rule breaking as a mediator in the association between GABRA2 and substance abuse outcomes was tested using prospective cross-lagged path models. RESULTS GABRA2 is significantly (p < 0.05) associated with rule breaking in mid- to late-adolescence, but not substance abuse symptomatology across adolescence. GABRA2 effects on problematic alcohol use and substance abuse symptomatology operate largely (45.3% and 71.1%, respectively, p < 0.05) via rule breaking in midadolescence. CONCLUSIONS GABRA2 represents an early risk factor for an externalizing pathway to the development of problematic alcohol and drug use.
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Affiliation(s)
| | - Sandra Villafuerte
- Molecular & Behavioral Neuroscience Institute, University of Michigan, USA
| | | | - Margit Burmeister
- Molecular & Behavioral Neuroscience Institute, University of Michigan, USA
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Bauer LO. Who gains? Genetic and neurophysiological correlates of BMI gain upon college entry in women. Appetite 2014; 82:160-5. [PMID: 25049133 PMCID: PMC4171201 DOI: 10.1016/j.appet.2014.07.007] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2014] [Revised: 06/30/2014] [Accepted: 07/11/2014] [Indexed: 01/27/2023]
Abstract
The present investigation examined P3 event-related electroencephalographic potentials and a short and selected list of addiction-related candidate gene single nucleotide polymorphisms (SNPs) within 84 female students, aged 18-20 yrs. The students were assigned to groups defined by the presence versus absence of a positive body mass index (BMI) change from the pre-college physical exam to the current day. Analyses revealed significantly greater P3 latencies and reduced P3 amplitudes during a response inhibition task among students who exhibited a BMI gain. BMI gain was also significantly associated with a ANKK1 SNP previously implicated in substance dependence risk. In logistic regression analyses, P3 latencies at the frontal electrode and this ANKK1 genotype correctly classified 71.1% of the students into the BMI groups. The present findings suggest that heritable indicators of impaired response inhibition can differentiate students who may be on a path toward an overweight or obese body mass.
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Affiliation(s)
- Lance O Bauer
- University of Connecticut School of Medicine, Farmington, CT 06030-2103, USA.
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Covault J, Pond T, Feinn R, Arias AJ, Oncken C, Kranzler HR. Dutasteride reduces alcohol's sedative effects in men in a human laboratory setting and reduces drinking in the natural environment. Psychopharmacology (Berl) 2014; 231:3609-18. [PMID: 24557088 PMCID: PMC4181572 DOI: 10.1007/s00213-014-3487-4] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/02/2013] [Accepted: 01/22/2014] [Indexed: 01/27/2023]
Abstract
RATIONALE Preclinical studies support the hypothesis that endogenous neuroactive steroids mediate some effects of alcohol. OBJECTIVES The aim of this study was to examine the effect of dutasteride inhibition of 5α-reduced neuroactive steroid production on subjective responses to alcohol in adult men. METHODS Using a within-subject factorial design, 70 men completed four randomly ordered monthly sessions in which pretreatment with 4 mg dutasteride or placebo was paired with a moderate dose of alcohol (0.8 g/kg) or placebo beverage. The pharmacologic effect of dutasteride was measured by an assay of serum androstanediol glucuronide. Self-reports of alcohol effects were obtained at 40-min intervals following alcohol administration using the Biphasic Alcohol Effects Scale (BAES) and the Alcohol Sensation Scale (SS). We used linear mixed models to examine the effects of dutasteride and alcohol on BAES and SS responses and the interaction of dutasteride with the GABRA2 alcohol dependence-associated polymorphism rs279858. We also examined whether exposure to dutasteride influenced drinking in the weeks following each laboratory session. RESULTS A single 4-mg dose of dutasteride produced a 70 % reduction in androstanediol glucuronide. Dutasteride pretreatment reduced alcohol effects on the BAES sedation and SS anesthesia scales. There was no interaction of dutasteride with rs279858. Heavy drinkers had fewer heavy drinking days during the 2 weeks following the dutasteride sessions and fewer total drinks in the first week after dutasteride. CONCLUSIONS These results provide evidence that neuroactive steroids mediate some of the sedative effects of alcohol in adult men and that dutasteride may reduce drinking, presumably through its effects on neuroactive steroid concentrations.
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Affiliation(s)
- Jonathan Covault
- Alcohol Research Center, Department of Psychiatry, University of Connecticut School of Medicine, Farmington, CT, USA,
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