1
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Cao J, Ball IK, Summerell E, Humburg P, Denson T, Rae CD. Effect of Ethanol on Brain Electrical Tissue Conductivity in Social Drinkers. J Magn Reson Imaging 2024. [PMID: 39105662 DOI: 10.1002/jmri.29548] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2024] [Revised: 07/09/2024] [Accepted: 07/11/2024] [Indexed: 08/07/2024] Open
Abstract
BACKGROUND How the biophysics of electrical conductivity measures relate to brain activity is poorly understood. The sedative, ethanol, reduces metabolic activity but its impact on brain electrical conductivity is unknown. PURPOSE To investigate whether ethanol reduces brain electrical tissue conductivity. STUDY TYPE Prospective. SUBJECTS Fifty-two healthy volunteers (aged 18-37 years, 22 females, 30 males). FIELD STRENGTH/SEQUENCE 3 T, T1-weighted, multi-shot, turbo-field echo (TFE); 3D balanced fast-field echo (bFFE). ASSESSMENT Brain gray and white matter tissue conductivity measured with phase-based magnetic resonance electrical properties tomography (MREPT) compared before and 20 minutes after ethanol consumption (0.7 g/kg body weight). Differential conductivity whole brain maps were generated for three subgroups: those with strong (∆ σ max $$ \Delta {\sigma}_{\mathrm{max}} $$ > 0.1 S/m; N = 33), weak (0.02 S/m ≤ ∆ σ max $$ \Delta {\sigma}_{\mathrm{max}} $$ ≤ 0.1 S/m; N = 9) conductivity decrease, and no significant response (∆ σ max $$ \Delta {\sigma}_{\mathrm{max}} $$ < 0.02 S/m, N = 10). Maps were compared in the strong response group where breath alcohol rose between scans, vs. those where it fell. STATISTICAL TESTS Average breath alcohol levels were compared to the differential conductivity maps using linear regression. T-maps were generated (threshold P < 0.05 and P < 0.001; minimum cluster 48 mm3). Differential conductivity maps were compared with ANOVA. RESULTS Whole-group analysis showed decreased conductivity that did not survive statistical thresholding. Strong responders (N = 33) showed a consistent pattern of significantly decreased conductivity (∆ σ max $$ \Delta {\sigma}_{\mathrm{max}} $$ > 0.1 S/m) in frontal/occipital and cerebellar white matter. The weak response group (N = 9) showed a similar pattern of conductivity decrease (0.02 S/m ≤ ∆ σ max $$ \Delta {\sigma}_{\mathrm{max}} $$ ≤ 0.1 S/m). There was no significant relationship with breath alcohol levels, alcohol use, age, ethnicity, or sex. The strong responders' regional response was different between ascending (N = 12) or descending (N = 20) alcohol during the scan. DATA CONCLUSION Ethanol reduces brain tissue conductivity in a participant-dependent and spatially dependent fashion. EVIDENCE LEVEL 1 TECHNICAL EFFICACY: Stage 2.
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Affiliation(s)
- Jun Cao
- Neuroscience Research Australia, Sydney, New South Wales, Australia
| | - Iain K Ball
- Philips Australia & New Zealand, North Ryde, New South Wales, Australia
| | - Elizabeth Summerell
- School of Psychology, The University of New South Wales, Sydney, New South Wales, Australia
| | - Peter Humburg
- Mark Wainwright Analytical Centre, Stats Central, The University of New South Wales, Sydney, New South Wales, Australia
| | - Tom Denson
- School of Psychology, The University of New South Wales, Sydney, New South Wales, Australia
| | - Caroline D Rae
- Neuroscience Research Australia, Sydney, New South Wales, Australia
- School of Psychology, The University of New South Wales, Sydney, New South Wales, Australia
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2
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Li Y, Yang L, Hao D, Chen Y, Ye-Lin Y, Li CSR, Li G. Functional Networks of Reward and Punishment Processing and Their Molecular Profiles Predicting the Severity of Young Adult Drinking. Brain Sci 2024; 14:610. [PMID: 38928610 PMCID: PMC11201596 DOI: 10.3390/brainsci14060610] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2024] [Revised: 06/15/2024] [Accepted: 06/16/2024] [Indexed: 06/28/2024] Open
Abstract
Alcohol misuse is associated with altered punishment and reward processing. Here, we investigated neural network responses to reward and punishment and the molecular profiles of the connectivity features predicting alcohol use severity in young adults. We curated the Human Connectome Project data and employed connectome-based predictive modeling (CPM) to examine how functional connectivity (FC) features during wins and losses are associated with alcohol use severity, quantified by Semi-Structured Assessment for the Genetics of Alcoholism, in 981 young adults. We combined the CPM findings and the JuSpace toolbox to characterize the molecular profiles of the network connectivity features of alcohol use severity. The connectomics predicting alcohol use severity appeared specific, comprising less than 0.12% of all features, including medial frontal, motor/sensory, and cerebellum/brainstem networks during punishment processing and medial frontal, fronto-parietal, and motor/sensory networks during reward processing. Spatial correlation analyses showed that these networks were associated predominantly with serotonergic and GABAa signaling. To conclude, a distinct pattern of network connectivity predicted alcohol use severity in young adult drinkers. These "neural fingerprints" elucidate how alcohol misuse impacts the brain and provide evidence of new targets for future intervention.
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Affiliation(s)
- Yashuang Li
- Department of Biomedical Engineering, College of Chemistry and Life Science, Beijing University of Technology, 100 Pingleyuan, Beijing 100124, China; (Y.L.)
| | - Lin Yang
- Department of Biomedical Engineering, College of Chemistry and Life Science, Beijing University of Technology, 100 Pingleyuan, Beijing 100124, China; (Y.L.)
- Beijing International Science and Technology Cooperation Base for Intelligent Physiological Measurement and Clinical Transformation, Beijing 100124, China
- BJUT-UPV Joint Research Laboratory in Biomedical Engineering, 46022 Valencia, Spain
| | - Dongmei Hao
- Department of Biomedical Engineering, College of Chemistry and Life Science, Beijing University of Technology, 100 Pingleyuan, Beijing 100124, China; (Y.L.)
- Beijing International Science and Technology Cooperation Base for Intelligent Physiological Measurement and Clinical Transformation, Beijing 100124, China
- BJUT-UPV Joint Research Laboratory in Biomedical Engineering, 46022 Valencia, Spain
| | - Yu Chen
- Department of Psychiatry, Yale University School of Medicine, New Haven, CT 06510, USA (C.-S.R.L.)
| | - Yiyao Ye-Lin
- BJUT-UPV Joint Research Laboratory in Biomedical Engineering, 46022 Valencia, Spain
- Centro de Investigación e Innovación en Bioingeniería, Universitat Politècnica de València, 46022 Valencia, Spain
| | - Chiang-Shan Ray Li
- Department of Psychiatry, Yale University School of Medicine, New Haven, CT 06510, USA (C.-S.R.L.)
- Department of Neuroscience, Yale University School of Medicine, New Haven, CT 06511, USA
- Interdepartmental Neuroscience Program, Yale University School of Medicine, New Haven, CT 06520, USA
- Wu Tsai Institute, Yale University, New Haven, CT 06511, USA
| | - Guangfei Li
- Department of Biomedical Engineering, College of Chemistry and Life Science, Beijing University of Technology, 100 Pingleyuan, Beijing 100124, China; (Y.L.)
- Beijing International Science and Technology Cooperation Base for Intelligent Physiological Measurement and Clinical Transformation, Beijing 100124, China
- BJUT-UPV Joint Research Laboratory in Biomedical Engineering, 46022 Valencia, Spain
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3
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Nieto SJ, Grodin EN, Ray LA. Neural correlates of the addictions neuroclinical assessment (ANA) incentive salience factor among individuals with alcohol use disorder. Behav Brain Res 2024; 464:114926. [PMID: 38431152 DOI: 10.1016/j.bbr.2024.114926] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2023] [Revised: 02/16/2024] [Accepted: 02/26/2024] [Indexed: 03/05/2024]
Abstract
The Addictions Neuroclinical Assessment (ANA) is a recently-developed framework offering a more holistic understanding of three neurofunctional and behavioral domains that reflect the neurobiological dysfunction seen in alcohol use disorder (AUD). While the ANA domains have been well-validated across independent laboratories, there is a critical need to identify neural markers that subserve the proposed neurofunctional domains. The current study involves secondary data analysis of a two-week experimental medication trial of ibudilast (50 mg BID). Forty-five non-treatment-seeking participants with AUD (17F / 28 M) completed a battery of validated behavioral assessments forming the basis of their incentive salience factor score, computed via factor analysis, as well as a functional neuroimaging (fMRI) task assessing their neural reactivity to visual alcohol cues after being on placebo or ibudilast for 7 days. General linear models were conducted to examine the relationship between incentive salience and neural alcohol cue-reactivity in the ventral and dorsal stratum. Whole-brain generalized linear model analyses were conducted to examine associations between neural alcohol cue-reactivity and incentive salience. Age, sex, medication, and smoking status were included as covariates. Incentive salience was not associated with cue-elicited activation in the dorsal or ventral striatum. Incentive salience was significantly positively correlated (p < 0.05) with alcohol cue-elicited brain activation in reward-learning and affective regions including the insula and posterior cingulate cortices, bilateral precuneus, and bilateral precentral gyri. The ANA incentive salience factor is reflected in brain circuitry important for reward learning and emotion processing. Identifying a sub-phenotype of AUD characterized by increased incentive salience to alcohol cues allows for precision medicine approaches, i.e. treatments specifically targeting craving and reward from alcohol use. This study serves as a preliminary bio-behavioral validation for the incentive salience factor of the ANA. Further studies validating the neural correlates of other ANA factors, as well as replication in larger samples, appear warranted.
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Affiliation(s)
- Steven J Nieto
- Department of Psychology, University of California at Los Angeles, Los Angeles, CA, USA
| | - Erica N Grodin
- Department of Psychiatry and Biobehavioral Sciences, University of California at Los Angeles, Los Angeles, CA, USA
| | - Lara A Ray
- Department of Psychology, University of California at Los Angeles, Los Angeles, CA, USA; Department of Psychiatry and Biobehavioral Sciences, University of California at Los Angeles, Los Angeles, CA, USA.
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4
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Fish KN, Joffe ME. Targeting prefrontal cortex GABAergic microcircuits for the treatment of alcohol use disorder. Front Synaptic Neurosci 2022; 14:936911. [PMID: 36105666 PMCID: PMC9465392 DOI: 10.3389/fnsyn.2022.936911] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2022] [Accepted: 07/27/2022] [Indexed: 11/17/2022] Open
Abstract
Developing novel treatments for alcohol use disorders (AUDs) is of paramount importance for improving patient outcomes and alleviating the suffering related to the disease. A better understanding of the molecular and neurocircuit mechanisms through which alcohol alters brain function will be instrumental in the rational development of new efficacious treatments. Clinical studies have consistently associated the prefrontal cortex (PFC) function with symptoms of AUDs. Population-level analyses have linked the PFC structure and function with heavy drinking and/or AUD diagnosis. Thus, targeting specific PFC cell types and neural circuits holds promise for the development of new treatments. Here, we overview the tremendous diversity in the form and function of inhibitory neuron subtypes within PFC and describe their therapeutic potential. We then summarize AUD population genetics studies, clinical neurophysiology findings, and translational neuroscience discoveries. This study collectively suggests that changes in fast transmission through PFC inhibitory microcircuits are a central component of the neurobiological effects of ethanol and the core symptoms of AUDs. Finally, we submit that there is a significant and timely need to examine sex as a biological variable and human postmortem brain tissue to maximize the efforts in translating findings to new clinical treatments.
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Affiliation(s)
| | - Max E. Joffe
- Translational Neuroscience Program, Department of Psychiatry, University of Pittsburgh, Pittsburgh, PA, United States
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5
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Trowbridge P, Poland C. Missing a case of nitrous oxide toxicity. Ther Adv Infect Dis 2022; 9:20499361221104377. [PMID: 35719176 PMCID: PMC9198419 DOI: 10.1177/20499361221104377] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2022] [Accepted: 05/13/2022] [Indexed: 11/16/2022] Open
Abstract
Nitrous oxide is a highly lipid-soluble molecule, which can produce euphoria and calming effects through noncompetitive antagonism of the N-methyl-D-aspartate (NMDA) glutamate receptor and agonism of the y-aminobutyric acid (GABA) A receptor. It can also produce toxicities likely through inactivation of methylcobalamin (vitamin B12) with subsequent neurological, psychiatric, and other sequelae that may be mistaken for other clinical entities. We present a classic presentation of nitrous oxide toxicity, which was missed and urgently referred to infectious diseases with concerns for an infectious neuromyelitis. Knowing the constellation of symptoms and findings and maintaining a high index of suspicion are key to diagnosing nitrous oxide toxicity, which can otherwise easily be missed. Cessation of use, B12 supplementation, and supportive measures such as occupational and physical therapy are helpful for maximizing long-term beneficial outcomes.
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Affiliation(s)
- Paul Trowbridge
- Addiction Medicine, Trinity Health Grand Rapids, 3000 Lafayette Ave SE, Suite 3200, Grand Rapids, MI 49503-4502, USA
| | - Cara Poland
- Department of Obstetrics, Gynecology and Reproductive Biology, College of Human Medicine, Michigan State University, East Lansing, MI, USA
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6
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An Innovatory GABA Receptor Modulator and Liver Oxidase System Microsomal Cytochrome P450 Activator in Patients with Alcoholism. Pharm Chem J 2021. [DOI: 10.1007/s11094-021-02327-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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7
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Cyders MA, Plawecki MH, Corbin W, King A, McCarthy DM, Ramchandani VA, Weafer J, O'Connor SJ. To Infuse or Ingest in Human Laboratory Alcohol Research. Alcohol Clin Exp Res 2020; 44:764-776. [PMID: 32056250 DOI: 10.1111/acer.14305] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2019] [Accepted: 02/02/2020] [Indexed: 02/06/2023]
Abstract
Human alcohol laboratory studies use two routes of alcohol administration: ingestion and infusion. The goal of this paper was to compare and contrast these alcohol administration methods. The work summarized in this report was the basis of a 2019 Research Society on Alcoholism Roundtable, "To Ingest or Infuse: A Comparison of Oral and Intravenous Alcohol Administration Methods for Human Alcohol Laboratory Designs." We review the methodological approaches of each and highlight strengths and weaknesses pertaining to different research questions. We summarize methodological considerations to aid researchers in choosing the most appropriate method for their inquiry, considering exposure variability, alcohol expectancy effects, safety, bandwidth, technical skills, documentation of alcohol exposure, experimental variety, ecological validity, and cost. Ingestion of alcohol remains a common and often a preferable, methodological practice in alcohol research. Nonetheless, the main problem with ingestion is that even the most careful calculation of dose and control of dosing procedures yields substantial and uncontrollable variability in the participants' brain exposures to alcohol. Infusion methodologies provide precise exposure control but are technically complex and may be limited in ecological validity. We suggest that alcohol ingestion research may not be the same thing as alcohol exposure research; investigators should be aware of the advantages and disadvantages that the choice between ingestion and infusion of alcohol invokes.
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Affiliation(s)
- Melissa A Cyders
- Department of Psychology, Indiana University Purdue University - Indianapolis, Indianapolis, Indiana, United States
| | - Martin H Plawecki
- Department of Psychiatry, Indiana University School of Medicine, Indianapolis, Indiana, United States
| | - William Corbin
- Department of Psychology, Arizona State University, Tempe, Arizona, United States
| | - Andrea King
- Department of Psychiatry, University of Chicago School of Medicine, Chicago, Illinois, United States
| | - Denis M McCarthy
- Department of Psychological Sciences, Universtiy of Missouri - Columbia, Columbia, Missouri, United States
| | - Vijay A Ramchandani
- Section on Human Psychopharmacology, National Institute on Alcohol Abuse and Alcoholism, Bethesda, Maryland, United States
| | - Jessica Weafer
- Department of Psychology, University of Kentucky, Lexington, Kentucky, United States
| | - Sean J O'Connor
- Department of Psychiatry, Indiana University School of Medicine, Indianapolis, Indiana, United States
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8
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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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9
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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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10
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Gorka SM, Phan KL, Childs E. Acute calming effects of alcohol are associated with disruption of the salience network. Addict Biol 2018; 23:921-930. [PMID: 28791789 DOI: 10.1111/adb.12537] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2017] [Revised: 05/26/2017] [Accepted: 06/22/2017] [Indexed: 01/09/2023]
Abstract
The mood-altering properties of alcohol are a key motivation for drinking, and people commonly report that they drink alcohol to alleviate stress or to relax. To date, the neural processes associated with the self-reported calming effects of alcohol are not well understood. Existing data imply that alcohol may target and disrupt activity within anterior insula (aINS) and amygdala-based neural networks, which are regions implicated in threat detection and anxious responding. The aims of the current study were (1) to examine the acute effect of alcohol upon functional connectivity within aINS and amygdala circuits and (2) to assess relationships between alcohol effects on functional connectivity and self-reported subjective mood. Healthy men and women (N = 39) who reported regular binge drinking completed a within-subjects, double-blind, placebo-controlled pharmacological functional magnetic resonance imaging experiment with i.v. infusions of either alcohol or placebo. Infusion profiles were personalized for each participant and raised breath alcohol concentration to 80 mg percent. Before, during and after infusions, participants rated their subjective mood (stimulation, sedation and calm). Results showed that alcohol dampened functional connectivity between bilateral aINS seed-regions-of-interest and the dorsal anterior cingulate cortex (dACC), key nodes of the salience network. Additionally, the more that alcohol reduced right aINS-dACC functional connectivity, the calmer participants felt during alcohol administration. Alcohol had no effect on amygdala functional connectivity. These findings suggest that alcohol disrupts aINS-dACC functional connectivity, which may impair detection and appraisal of emotionally salient information and relate to acute relaxing effects of the drug.
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Affiliation(s)
- Stephanie M. Gorka
- Department of Psychiatry; University of Illinois at Chicago; Chicago IL USA
| | - K. Luan Phan
- Department of Psychiatry; University of Illinois at Chicago; Chicago IL USA
- Department of Anatomy and Cell Biology and the Graduate Program in Neuroscience; University of Illinois at Chicago; Chicago IL USA
- Mental Health Service Line; Jesse Brown VA Medical Center; Chicago IL USA
| | - Emma Childs
- Department of Psychiatry; University of Illinois at Chicago; Chicago IL USA
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11
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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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12
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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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13
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Chandler CM, Overton JS, Rüedi-Bettschen D, Platt DM. GABA A Receptor Subtype Mechanisms and the Abuse-Related Effects of Ethanol: Genetic and Pharmacological Evidence. Handb Exp Pharmacol 2018; 248:3-27. [PMID: 29204713 DOI: 10.1007/164_2017_80] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Ethanol's reinforcing and subjective effects, as well as its ability to induce relapse, are powerful factors contributing to its widespread use and abuse. A significant mediator of these behavioral effects is the GABAA receptor system. GABAA receptors are the target for γ-aminobutyric acid (GABA), the major inhibitory neurotransmitter in the CNS. Structurally, they are pentameric, transmembrane chloride ion channels comprised of subunits from at least eight different families of distinct proteins. The contribution of different GABAA subunits to ethanol's diverse abuse-related effects is not clear and remains an area of research focus. This chapter details the clinical and preclinical findings supporting roles for different α, β, γ, and δ subunit-containing GABAA receptors in ethanol's reinforcing, subjective/discriminative stimulus, and relapse-inducing effects. The reinforcing properties of ethanol have been studied the most systematically, and convergent preclinical evidence suggests a key role for the α5 subunit in those effects. Regarding ethanol's subjective/discriminative stimulus effects, clinical and genetic findings support a primary role for the α2 subunit, whereas preclinical evidence implicates the α5 subunit. At present, too few studies investigating ethanol relapse exist to make any solid conclusions regarding the role of specific GABAA subunits in this abuse-related effect.
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Affiliation(s)
- Cassie M Chandler
- Graduate Program in Neuroscience, University of Mississippi Medical Center, Jackson, MS, USA
| | - John S Overton
- Department of Psychiatry and Human Behavior, University of Mississippi Medical Center, Jackson, MS, USA
| | - Daniela Rüedi-Bettschen
- Department of Psychiatry and Human Behavior, University of Mississippi Medical Center, Jackson, MS, USA
| | - Donna M Platt
- Graduate Program in Neuroscience, University of Mississippi Medical Center, Jackson, MS, USA.
- Department of Psychiatry and Human Behavior, University of Mississippi Medical Center, Jackson, MS, USA.
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14
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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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15
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Meyers JL, Zhang J, Wang JC, Su J, Kuo SI, Kapoor M, Wetherill L, Bertelsen S, Lai D, Salvatore JE, Kamarajan C, Chorlian D, Agrawal A, Almasy L, Bauer L, Bucholz KK, Chan G, Hesselbrock V, Koganti L, Kramer J, Kuperman S, Manz N, Pandey A, Seay M, Scott D, Taylor RE, Dick DM, Edenberg HJ, Goate A, Foroud T, Porjesz B. An endophenotype approach to the genetics of alcohol dependence: a genome wide association study of fast beta EEG in families of African ancestry. Mol Psychiatry 2017; 22:1767-1775. [PMID: 28070124 PMCID: PMC5503794 DOI: 10.1038/mp.2016.239] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/17/2016] [Revised: 09/24/2016] [Accepted: 10/27/2016] [Indexed: 01/16/2023]
Abstract
Fast beta (20-28 Hz) electroencephalogram (EEG) oscillatory activity may be a useful endophenotype for studying the genetics of disorders characterized by neural hyperexcitability, including substance use disorders (SUDs). However, the genetic underpinnings of fast beta EEG have not previously been studied in a population of African-American ancestry (AA). In a sample of 2382 AA individuals from 482 families drawn from the Collaborative Study on the Genetics of Alcoholism (COGA), we performed a genome-wide association study (GWAS) on resting-state fast beta EEG power. To further characterize our genetic findings, we examined the functional and clinical/behavioral significance of GWAS variants. Ten correlated single-nucleotide polymorphisms (SNPs) (r2>0.9) located in an intergenic region on chromosome 3q26 were associated with fast beta EEG power at P<5 × 10-8. The most significantly associated SNP, rs11720469 (β: -0.124; P<4.5 × 10-9), is also an expression quantitative trait locus for BCHE (butyrylcholinesterase), expressed in thalamus tissue. Four of the genome-wide SNPs were also associated with Diagnostic and Statistical Manual of Mental Disorders Alcohol Dependence in COGA AA families, and two (rs13093097, rs7428372) were replicated in an independent AA sample (Gelernter et al.). Analyses in the AA adolescent/young adult (offspring from COGA families) subsample indicated association of rs11720469 with heavy episodic drinking (frequency of consuming 5+ drinks within 24 h). Converging findings presented in this study provide support for the role of genetic variants within 3q26 in neural and behavioral disinhibition. These novel genetic findings highlight the importance of including AA populations in genetics research on SUDs and the utility of the endophenotype approach in enhancing our understanding of mechanisms underlying addiction susceptibility.
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Affiliation(s)
- J L Meyers
- Department of Psychiatry, State University of New York Downstate Medical Center, Brooklyn, NY, USA
| | - J Zhang
- Department of Psychiatry, State University of New York Downstate Medical Center, Brooklyn, NY, USA
| | - J C Wang
- Department of Neuroscience, Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - J Su
- Department of Psychology, Virginia Commonwealth University, Richmond, VA, USA
| | - S I Kuo
- Department of Psychology, Virginia Commonwealth University, Richmond, VA, USA
| | - M Kapoor
- Department of Neuroscience, Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - L Wetherill
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis, IN, USA
| | - S Bertelsen
- Department of Neuroscience, Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - D Lai
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis, IN, USA
| | - J E Salvatore
- Department of Psychology, Virginia Commonwealth University, Richmond, VA, USA
- Virginia Institute of Psychiatric and Behavioral Genetics, Virginia Commonwealth University, Richmond, VA, USA
| | - C Kamarajan
- Department of Psychiatry, State University of New York Downstate Medical Center, Brooklyn, NY, USA
| | - D Chorlian
- Department of Psychiatry, State University of New York Downstate Medical Center, Brooklyn, NY, USA
| | - A Agrawal
- Department of Psychiatry, Washington University School of Medicine in St Louis, St Louis, MO, USA
| | - L Almasy
- Department of Biomedical and Health Informatics, The Children's Hospital of Philadelphia, Philadelphia, PA, USA
- Department of Genetics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - L Bauer
- Department of Psychiatry, University of Connecticut School of Medicine, Farmington, CT, USA
| | - K K Bucholz
- Department of Psychiatry, Washington University School of Medicine in St Louis, St Louis, MO, USA
| | - G Chan
- Department of Psychiatry, University of Connecticut School of Medicine, Farmington, CT, USA
| | - V Hesselbrock
- Department of Psychiatry, University of Connecticut School of Medicine, Farmington, CT, USA
| | - L Koganti
- Department of Neuroscience, Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - J Kramer
- Department of Psychiatry, University of Iowa Carver College of Medicine, Iowa City, IA, USA
| | - S Kuperman
- Department of Psychiatry, University of Iowa Carver College of Medicine, Iowa City, IA, USA
| | - N Manz
- Department of Physics, The College of Wooster, Wooster, OH, USA
| | - A Pandey
- Department of Psychiatry, State University of New York Downstate Medical Center, Brooklyn, NY, USA
| | - M Seay
- Department of Psychiatry, State University of New York Downstate Medical Center, Brooklyn, NY, USA
| | - D Scott
- Collaborative Alcohol Research Center, Howard University College of Medicine, Washington, DC, USA
| | - R E Taylor
- Collaborative Alcohol Research Center, Howard University College of Medicine, Washington, DC, USA
| | - D M Dick
- Department of Psychology, Virginia Commonwealth University, Richmond, VA, USA
- Virginia Institute of Psychiatric and Behavioral Genetics, Virginia Commonwealth University, Richmond, VA, USA
| | - H J Edenberg
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis, IN, USA
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, IN, USA
| | - A Goate
- Department of Neuroscience, Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, USA
- Department of Neurology, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - T Foroud
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis, IN, USA
| | - B Porjesz
- Department of Psychiatry, State University of New York Downstate Medical Center, Brooklyn, NY, USA
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16
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Olsen RW, Liang J. Role of GABA A receptors in alcohol use disorders suggested by chronic intermittent ethanol (CIE) rodent model. Mol Brain 2017; 10:45. [PMID: 28931433 PMCID: PMC5605989 DOI: 10.1186/s13041-017-0325-8] [Citation(s) in RCA: 73] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2017] [Accepted: 09/05/2017] [Indexed: 11/10/2022] Open
Abstract
GABAergic inhibitory transmission is involved in the acute and chronic effects of ethanol on the brain and behavior. One-dose ethanol exposure induces transient plastic changes in GABAA receptor subunit levels, composition, and regional and subcellular localization. Rapid down-regulation of early responder δ subunit-containing GABAA receptor subtypes mediating ethanol-sensitive tonic inhibitory currents in critical neuronal circuits corresponds to rapid tolerance to ethanol's behavioral responses. Slightly slower, α1 subunit-containing GABAA receptor subtypes mediating ethanol-insensitive synaptic inhibition are down-regulated, corresponding to tolerance to additional ethanol behaviors plus cross-tolerance to other GABAergic drugs including benzodiazepines, anesthetics, and neurosteroids, especially sedative-hypnotic effects. Compensatory up-regulation of synaptically localized α4 and α2 subunit-containing GABAA receptor subtypes, mediating ethanol-sensitive synaptic inhibitory currents follow, but exhibit altered physio-pharmacology, seizure susceptibility, hyperexcitability, anxiety, and tolerance to GABAergic positive allosteric modulators, corresponding to heightened alcohol withdrawal syndrome. All these changes (behavioral, physiological, and biochemical) induced by ethanol administration are transient and return to normal in a few days. After chronic intermittent ethanol (CIE) treatment the same changes are observed but they become persistent after 30 or more doses, lasting for at least 120 days in the rat, and probably for life. We conclude that the ethanol-induced changes in GABAA receptors represent aberrant plasticity contributing critically to ethanol dependence and increased voluntary consumption. We suggest that the craving, drug-seeking, and increased consumption in the rat model are tied to ethanol-induced plastic changes in GABAA receptors, importantly the development of ethanol-sensitive synaptic GABAA receptor-mediating inhibitory currents that participate in maintained positive reward actions of ethanol on critical neuronal circuits. These probably disinhibit nerve endings of inhibitory GABAergic neurons on dopamine reward circuit cells, and limbic system circuits mediating anxiolysis in hippocampus and amygdala. We further suggest that the GABAA receptors contributing to alcohol dependence in the rat and presumably in human alcohol use disorders (AUD) are the ethanol-induced up-regulated subtypes containing α4 and most importantly α2 subunits. These mediate critical aspects of the positive reinforcement of ethanol in the dependent chronic user while alleviating heightened withdrawal symptoms experienced whenever ethanol is absent. The speculative conclusions based on firm observations are readily testable.
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Affiliation(s)
- Richard W. Olsen
- Department of Molecular and Medical Pharmacology, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095 USA
| | - Jing Liang
- Department of Molecular and Medical Pharmacology, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095 USA
- Titus Family Department of Clinical Pharmacy, School of Pharmacy, University of Southern California, Los Angeles, CA 90089 USA
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17
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Meyers JL, Zhang J, Manz N, Rangaswamy M, Kamarajan C, Wetherill L, Chorlian DB, Kang SJ, Bauer L, Hesselbrock V, Kramer J, Kuperman S, Nurnberger JI, Tischfield J, Wang JC, Edenberg HJ, Goate A, Foroud T, Porjesz B. A genome wide association study of fast beta EEG in families of European ancestry. Int J Psychophysiol 2017; 115:74-85. [PMID: 28040410 PMCID: PMC5426060 DOI: 10.1016/j.ijpsycho.2016.12.008] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2015] [Revised: 12/08/2016] [Accepted: 12/15/2016] [Indexed: 11/25/2022]
Abstract
BACKGROUND Differences in fast beta (20-28Hz) electroencephalogram (EEG) oscillatory activity distinguish some individuals with psychiatric and substance use disorders, suggesting that it may be a useful endophenotype for studying the genetics of disorders characterized by neural hyper-excitability. Despite the high heritability estimates provided by twin and family studies, there have been relatively few genetic studies of beta EEG, and to date only one genetic association finding has replicated (i.e., GABRA2). METHOD In a sample of 1564 individuals from 117 families of European Ancestry (EA) drawn from the Collaborative Study on the Genetics of Alcoholism (COGA), we performed a Genome-Wide Association Study (GWAS) on resting-state fronto-central fast beta EEG power, adjusting regression models for family relatedness, age, sex, and ancestry. To further characterize genetic findings, we examined the functional and behavioral significance of GWAS findings. RESULTS Three intronic variants located within DSE (dermatan sulfate epimerase) on 6q22 were associated with fast beta EEG at a genome wide significant level (p<5×10-8). The most significant SNP was rs2252790 (p<2.6×10-8; MAF=0.36; β=0.135). rs2252790 is an eQTL for ROS1 expressed most robustly in the temporal cortex (p=1.2×10-6) and for DSE/TSPYL4 expressed most robustly in the hippocampus (p=7.3×10-4; β=0.29). Previous studies have indicated that DSE is involved in a network of genes integral to membrane organization; gene-based tests indicated that several variants within this network (i.e., DSE, ZEB2, RND3, MCTP1, and CTBP2) were also associated with beta EEG (empirical p<0.05), and of these genes, ZEB2 and CTBP2 were associated with DSM-V Alcohol Use Disorder (AUD; empirical p<0.05).' DISCUSSION In this sample of EA families enriched for AUDs, fast beta EEG is associated with variants within DSE on 6q22; the most significant SNP influences the mRNA expression of DSE and ROS1 in hippocampus and temporal cortex, brain regions important for beta EEG activity. Gene-based tests suggest evidence of association with related genes, ZEB2, RND3, MCTP1, CTBP2, and beta EEG. Converging data from GWAS, gene expression, and gene-networks presented in this study provide support for the role of genetic variants within DSE and related genes in neural hyperexcitability, and has highlighted two potential candidate genes for AUD and/or related neurological conditions: ZEB2 and CTBP2. However, results must be replicated in large, independent samples.
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Affiliation(s)
- Jacquelyn L Meyers
- Henri Begleiter Neurodynamics Laboratory, Department of Psychiatry and Behavioral Sciences, SUNY Downstate Medical Center, Brooklyn, NY, USA.
| | - Jian Zhang
- Henri Begleiter Neurodynamics Laboratory, Department of Psychiatry and Behavioral Sciences, SUNY Downstate Medical Center, Brooklyn, NY, USA
| | - Niklas Manz
- Henri Begleiter Neurodynamics Laboratory, Department of Psychiatry and Behavioral Sciences, SUNY Downstate Medical Center, Brooklyn, NY, USA; Department of Physics, College of Wooster, Wooster, OH, USA
| | | | - Chella Kamarajan
- Henri Begleiter Neurodynamics Laboratory, Department of Psychiatry and Behavioral Sciences, SUNY Downstate Medical Center, Brooklyn, NY, USA
| | - Leah Wetherill
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis, IN, USA
| | - David B Chorlian
- Henri Begleiter Neurodynamics Laboratory, Department of Psychiatry and Behavioral Sciences, SUNY Downstate Medical Center, Brooklyn, NY, USA
| | - Sun J Kang
- Albany Stratton VA Medical Center, Albany, NY, USA
| | - Lance Bauer
- University of Connecticut School of Medicine, Farmington, CT, USA
| | | | - John Kramer
- Department of Psychiatry, University of Iowa, Iowa City, IA, USA
| | - Samuel Kuperman
- Department of Psychiatry, University of Iowa, Iowa City, IA, USA
| | - John I Nurnberger
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis, IN, USA
| | | | | | - Howard J Edenberg
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis, IN, USA; Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Alison Goate
- Icahn School of Medicine at Mt. Sinai, New York, NY, USA
| | - Tatiana Foroud
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Bernice Porjesz
- Henri Begleiter Neurodynamics Laboratory, Department of Psychiatry and Behavioral Sciences, SUNY Downstate Medical Center, Brooklyn, NY, USA
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18
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Bujarski S, Ray LA. Experimental psychopathology paradigms for alcohol use disorders: Applications for translational research. Behav Res Ther 2016; 86:11-22. [PMID: 27266992 PMCID: PMC5067182 DOI: 10.1016/j.brat.2016.05.008] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2016] [Revised: 05/12/2016] [Accepted: 05/26/2016] [Indexed: 02/05/2023]
Abstract
In spite of high prevalence and disease burden, scientific consensus on the etiology and treatment of Alcohol Use Disorder (AUD) has yet to be reached. The development and utilization of experimental psychopathology paradigms in the human laboratory represents a cornerstone of AUD research. In this review, we describe and critically evaluate the major experimental psychopathology paradigms developed for AUD, with an emphasis on their implications, strengths, weaknesses, and methodological considerations. Specifically we review alcohol administration, self-administration, cue-reactivity, and stress-reactivity paradigms. We also provide an introduction to the application of experimental psychopathology methods to translational research including genetics, neuroimaging, pharmacological and behavioral treatment development, and translational science. Through refining and manipulating key phenotypes of interest, these experimental paradigms have the potential to elucidate AUD etiological factors, improve the efficiency of treatment developments, and refine treatment targets thus advancing precision medicine.
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Affiliation(s)
- Spencer Bujarski
- Department of Psychology, University of California, Los Angeles, United States.
| | - Lara A Ray
- Department of Psychology, University of California, Los Angeles, United States; Department of Psychiatry and Biobehavioral Sciences, University of California, Los Angeles, United States
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19
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Ray LA, Bujarski S, Roche DJO. Subjective Response to Alcohol as a Research Domain Criterion. Alcohol Clin Exp Res 2016; 40:6-17. [PMID: 26727518 DOI: 10.1111/acer.12927] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2014] [Accepted: 10/12/2015] [Indexed: 01/03/2023]
Abstract
BACKGROUND Individual differences in the subjective experience of the pharmacological effects of alcohol have long been implicated in the likelihood that one will drink heavily and develop alcoholism. The theme of this conceptual review and perspective article is to synthesize the literature on subjective responses to alcohol and to set an agenda for the next generation of research in the area. Specifically, we contend that in order for subjective response to alcohol to play a prominent role in alcoholism research, it is critical that it be studied as a multimodal phenotype. METHODS First, we review the human research on subjective response to alcohol measured under controlled laboratory conditions and draw recommendations for the application of these findings to understanding alcoholism neurobiology in humans. Second, we highlight multimodal approaches, including studies of the genetic and neural substrates of individual differences in subjective response to alcohol. Third, we review treatment implications with a focus on subjective response to alcohol as an intervention target. Upon review of the research on subjective response to alcohol across levels of analyses, we provide recommendations for leveraging these phenotypes in a systematic and methodologically rigorous fashion that can address central questions about alcoholism etiology, disease progression, and personalized treatment. DISCUSSION The approach recommended herein is largely consistent with the Research Domain Criteria (RDoC) initiative across the National Institute of Mental Health. The defining feature of such domains is that they inform behavior yet be amenable to examination through multiple units of analysis, such as molecular, genetic, circuit-level, and behavioral measurements. To that end, we contend that subjective response to alcohol represents a behaviorally and biologically plausible phenotype upon which to build using the RDoC framework for understanding alcohol use disorder.
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Affiliation(s)
- Lara A Ray
- Department of Psychology, University of California, Los Angeles, Los Angeles, California
| | - Spencer Bujarski
- Department of Psychology, University of California, Los Angeles, Los Angeles, California
| | - Daniel J O Roche
- Department of Psychology, University of California, Los Angeles, Los Angeles, California
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20
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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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21
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Kwako LE, Momenan R, Litten RZ, Koob GF, Goldman D. Addictions Neuroclinical Assessment: A Neuroscience-Based Framework for Addictive Disorders. Biol Psychiatry 2016; 80:179-89. [PMID: 26772405 PMCID: PMC4870153 DOI: 10.1016/j.biopsych.2015.10.024] [Citation(s) in RCA: 227] [Impact Index Per Article: 28.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/14/2015] [Revised: 10/30/2015] [Accepted: 10/30/2015] [Indexed: 02/06/2023]
Abstract
This article proposes a heuristic framework for the Addictions Neuroclinical Assessment that incorporates key functional domains derived from the neurocircuitry of addiction. We review how addictive disorders (ADs) are presently diagnosed and the need for new neuroclinical measures to differentiate patients who meet clinical criteria for addiction to the same agent while differing in etiology, prognosis, and treatment response. The need for a better understanding of the mechanisms provoking and maintaining addiction, as evidenced by the limitations of current treatments and within-diagnosis clinical heterogeneity, is articulated. In addition, recent changes in the nosology of ADs, challenges to current classification systems, and prior attempts to subtype individuals with ADs are described. Complementary initiatives, including the Research Domain Criteria project, that have established frameworks for the neuroscience of psychiatric disorders are discussed. Three domains-executive function, incentive salience, and negative emotionality-tied to different phases in the cycle of addiction form the core functional elements of ADs. Measurement of these domains in epidemiologic, genetic, clinical, and treatment studies will provide the underpinnings for an understanding of cross-population and temporal variation in addictions, shared mechanisms in addictive disorders, impact of changing environmental influences, and gene identification. Finally, we show that it is practical to implement such a deep neuroclinical assessment using a combination of neuroimaging and performance measures. Neuroclinical assessment is key to reconceptualizing the nosology of ADs on the basis of process and etiology, an advance that can lead to improved prevention and treatment.
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Affiliation(s)
- Laura E Kwako
- Office of the Clinical Director, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, Maryland.
| | - Reza Momenan
- Section on Brain Electrophysiology and Imaging, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, Maryland
| | - Raye Z Litten
- Division of Intramural Clinical and Biological Research; Division of Treatment and Recovery Research, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, Maryland
| | - George F Koob
- Office of the Director, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, Maryland
| | - David Goldman
- Office of the Clinical Director, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, Maryland; Laboratory of Neurogenetics, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, Maryland
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22
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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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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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24
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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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Roche DJ, Ray LA. Subjective response as a consideration in the pharmacogenetics of alcoholism treatment. Pharmacogenomics 2015; 16:721-36. [PMID: 25950242 DOI: 10.2217/pgs.14.143] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Currently available pharmacological treatments for alcoholism have modest efficacy and high individual variability in treatment outcomes, both of which have been partially attributed to genetic factors. One path to reducing the variability and improving the efficacy associated with these pharmacotherapies may be to identify overlapping genetic contributions to individual differences in both subjective responses to alcohol and alcoholism pharmacotherapy outcomes. As acute subjective response to alcohol is highly predictive of future alcohol related problems, identifying such shared genetic mechanisms may inform the development of personalized treatments that can effectively target converging pathophysiological mechanisms that convey risk for alcoholism. The focus of this review is to revisit the association between subjective response to alcohol and the etiology of alcoholism while also describing genetic contributions to this relationship, discuss potential pharmacogenetic approaches to target subjective response to alcohol in order to improve the treatment of alcoholism and examine conceptual and methodological issues associated with these topics, and outline future approaches to overcome these challenges.
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Affiliation(s)
- Daniel Jo Roche
- 1Department of Psychology, University of California, 1285 Franz Hall, Box 951563, Los Angeles, CA 90095-1563, USA
| | - Lara A Ray
- 1Department of Psychology, University of California, 1285 Franz Hall, Box 951563, Los Angeles, CA 90095-1563, USA
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26
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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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27
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Jin Z, Bhandage AK, Bazov I, Kononenko O, Bakalkin G, Korpi ER, Birnir B. Expression of specific ionotropic glutamate and GABA-A receptor subunits is decreased in central amygdala of alcoholics. Front Cell Neurosci 2014; 8:288. [PMID: 25278838 PMCID: PMC4165314 DOI: 10.3389/fncel.2014.00288] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2014] [Accepted: 08/29/2014] [Indexed: 01/20/2023] Open
Abstract
The central amygdala (CeA) has a role for mediating fear and anxiety responses. It is also involved in emotional imbalance caused by alcohol abuse and dependence and in regulating relapse to alcohol abuse. Growing evidences suggest that excitatory glutamatergic and inhibitory γ-aminobutyric acid-ergic (GABAergic) transmissions in the CeA are affected by chronic alcohol exposure. Human post-mortem CeA samples from male alcoholics (n = 9) and matched controls (n = 9) were assayed for the expression level of ionotropic glutamate and GABA-A receptors subunit mRNAs using quantitative real-time reverse transcription-PCR (RT-qPCR). Our data revealed that out of the 16 ionotropic glutamate receptor subunits, mRNAs encoding two AMPA [2-amino-3-(3-hydroxy-5-methyl-isoxazol-4-yl)propanoic acid] receptor subunits GluA1 and GluA4; one kainate receptor subunit GluK2; one NMDA (N-methyl-D-aspartate) receptor subunit GluN2D and one delta receptor subunit GluD2 were significantly decreased in the CeA of alcoholics. In contrast, of the 19 GABA-A receptor subunits, only the mRNA encoding the α2 subunit was significantly down-regulated in the CeA of the alcoholics as compared with control subjects. Our findings imply that the down-regulation of specific ionotropic glutamate and GABA-A receptor subunits in the CeA of alcoholics may represent one of the molecular substrates underlying the new balance between excitatory and inhibitory neurotransmission in alcohol dependence.
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Affiliation(s)
- Zhe Jin
- Molecular Physiology and Neuroscience Unit, Neuroscience, Biomedical Center, Uppsala University Uppsala, Sweden
| | - Amol K Bhandage
- Molecular Physiology and Neuroscience Unit, Neuroscience, Biomedical Center, Uppsala University Uppsala, Sweden
| | - Igor Bazov
- Division of Biological Research on Drug Dependence, Department of Pharmaceutical Biosciences, Uppsala University Uppsala, Sweden
| | - Olga Kononenko
- Division of Biological Research on Drug Dependence, Department of Pharmaceutical Biosciences, Uppsala University Uppsala, Sweden
| | - Georgy Bakalkin
- Division of Biological Research on Drug Dependence, Department of Pharmaceutical Biosciences, Uppsala University Uppsala, Sweden
| | - Esa R Korpi
- Pharmacology, Institute of Biomedicine, University of Helsinki Helsinki, Finland
| | - Bryndis Birnir
- Molecular Physiology and Neuroscience Unit, Neuroscience, Biomedical Center, Uppsala University Uppsala, Sweden
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28
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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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29
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Liang J, Olsen RW. Alcohol use disorders and current pharmacological therapies: the role of GABA(A) receptors. Acta Pharmacol Sin 2014; 35:981-93. [PMID: 25066321 PMCID: PMC4125717 DOI: 10.1038/aps.2014.50] [Citation(s) in RCA: 86] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2014] [Accepted: 05/16/2014] [Indexed: 12/18/2022] Open
Abstract
Alcohol use disorders (AUD) are defined as alcohol abuse and alcohol dependence, which create large problems both for society and for the drinkers themselves. To date, no therapeutic can effectively solve these problems. Understanding the underlying mechanisms leading to AUD is critically important for developing effective and safe pharmacological therapies. Benzodiazepines (BZs) are used to reduce the symptoms of alcohol withdrawal syndrome. However, frequent use of BZs causes cross-tolerance, dependence, and cross-addiction to alcohol. The FDA-approved naltrexone and acamprosate have shown mixed results in clinical trials. Naltrexone is effective to treat alcohol dependence (decreased length and frequency of drinking bouts), but its severe side effects, including withdrawal symptoms, are difficult to overcome. Acamprosate showed efficacy for treating alcohol dependence in European trials, but two large US trials have failed to confirm the efficacy. Another FDA-approved medication, disulfiram, does not diminish craving, and it causes a peripheral neuropathy. Kudzu is the only natural medication mentioned by the National Institute on Alcohol Abuse and Alcoholism, but its mechanisms of action are not yet established. It has been recently shown that dihydromyricetin, a flavonoid purified from Hovenia, has unique effects on GABAA receptors and blocks ethanol intoxication and withdrawal in alcoholic animal models. In this article, we review the role of GABAA receptors in the treatment of AUD and currently available and potentially novel pharmacological agents.
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Affiliation(s)
- Jing Liang
- Department of Molecular & Medical Pharmacology, David Geffen School of Medicine, University of California, Los Angeles, CA, USA
| | - Richard W Olsen
- Department of Molecular & Medical Pharmacology, David Geffen School of Medicine, University of California, Los Angeles, CA, USA
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30
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Leeman RF, Ralevski E, Limoncelli D, Pittman B, O'Malley SS, Petrakis IL. Relationships between impulsivity and subjective response in an IV ethanol paradigm. Psychopharmacology (Berl) 2014; 231:2867-76. [PMID: 24553574 PMCID: PMC4101083 DOI: 10.1007/s00213-014-3458-9] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/14/2013] [Accepted: 01/14/2014] [Indexed: 11/26/2022]
Abstract
RATIONALE Impulsivity and individual differences in subjective response to alcohol are risk factors for alcohol problems and possibly endophenotypes for alcohol dependence. Few prior studies have addressed relationships between the two constructs. OBJECTIVES To predict subjective responses to ethanol, we tested self-reported impulsiveness, ethanol dose condition (high dose, low dose, or placebo), and time (seven time points) along with interactions among these variables. METHODS The present study is a secondary analysis of data from a within-subject, placebo-controlled, dose-ranging ethanol administration study using IV infusion with a clamping technique to maintain steady-state breath alcohol concentration. The sample consisted of healthy, non-alcohol dependent social alcohol drinkers between the ages of 21 and 30 (N=105). Participants at varying levels of impulsivity were compared with regard to stimulant and subjective responses to three ethanol dose conditions over time. RESULTS Individuals with higher impulsivity reported elavated stimulant and dampened sedative response to alcohol, particularly at the higher dose. Higher impulsivity was associated with a steeper increase in stimulant effects during the first half of clamped ethanol infusion with the higher dose. CONCLUSIONS These results suggest that impulsive individuals may experience enhanced reinforcing, stimulant effects, and relatively muted aversive sedative effects from alcohol. These subjective responses may relate to enhanced risk of alcohol problems among more impulsive individuals.
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Affiliation(s)
- Robert F Leeman
- Department of Psychiatry, Yale School of Medicine, CMHC, Room S200, 34 Park Street, New Haven, CT, 06519, USA,
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31
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Chen CH, Ferreira JCB, Gross ER, Mochly-Rosen D. Targeting aldehyde dehydrogenase 2: new therapeutic opportunities. Physiol Rev 2014; 94:1-34. [PMID: 24382882 DOI: 10.1152/physrev.00017.2013] [Citation(s) in RCA: 421] [Impact Index Per Article: 42.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
A family of detoxifying enzymes called aldehyde dehydrogenases (ALDHs) has been a subject of recent interest, as its role in detoxifying aldehydes that accumulate through metabolism and to which we are exposed from the environment has been elucidated. Although the human genome has 19 ALDH genes, one ALDH emerges as a particularly important enzyme in a variety of human pathologies. This ALDH, ALDH2, is located in the mitochondrial matrix with much known about its role in ethanol metabolism. Less known is a new body of research to be discussed in this review, suggesting that ALDH2 dysfunction may contribute to a variety of human diseases including cardiovascular diseases, diabetes, neurodegenerative diseases, stroke, and cancer. Recent studies suggest that ALDH2 dysfunction is also associated with Fanconi anemia, pain, osteoporosis, and the process of aging. Furthermore, an ALDH2 inactivating mutation (termed ALDH2*2) is the most common single point mutation in humans, and epidemiological studies suggest a correlation between this inactivating mutation and increased propensity for common human pathologies. These data together with studies in animal models and the use of new pharmacological tools that activate ALDH2 depict a new picture related to ALDH2 as a critical health-promoting enzyme.
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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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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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Abstract
Alcoholism has a substantial heritability yet the detection of specific genetic influences has largely proved elusive. The strongest findings are with genes encoding alcohol metabolizing enzymes. A few candidate genes such as GABRA2 have shown robust associations with alcoholism. Moreover, it has become apparent that variants in stress-related genes such as CRHR1, may only confer risk in individuals exposed to trauma, particularly in early life. Over the past decade there have been tremendous advances in large scale SNP genotyping technologies allowing for genome-wide associations studies (GWAS). As a result, it is now recognized that genetic risk for alcoholism is likely to be due to common variants in very many genes, each of small effect, although rare variants with large effects might also play a role. This has resulted in a paradigm shift away from gene centric studies toward analyses of gene interactions and gene networks within biologically relevant pathways.
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Affiliation(s)
- Mary-Anne Enoch
- Laboratory of Neurogenetics, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, MD, 20892, USA,
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35
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Arias AJ, Covault J, Feinn R, Pond T, Yang BZ, Ge W, Oncken C, Kranzler HR. A GABRA2 variant is associated with increased stimulation and 'high' following alcohol administration. Alcohol Alcohol 2013; 49:1-9. [PMID: 24166645 DOI: 10.1093/alcalc/agt163] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
AIMS Variation in genes encoding GABAA receptor subunits has been implicated in the risk of alcohol dependence (AD). We sought to replicate and extend previous findings of a moderating effect of single nucleotide polymorphisms (SNPs) in GABRA2 (which encodes the GABAA α-2 subunit) on the subjective effects of alcohol by examining SNPs in this and the adjacent GABRG1 gene on chromosome 4. METHODS Fifty-two European-Americans (22 males, 28 light drinkers and 24 heavy drinkers) completed 3 laboratory sessions, during which they drank low-dose, high-dose, or placebo alcohol prior to undergoing periodic assessments of stimulation, sedation and drug enjoyment. We genotyped subjects for three SNPs previously associated with AD: rs279858 in GABRA2, and rs7654165 and rs6447493 in GABRG1. RESULTS Two SNPs were associated with altered stimulatory effects of alcohol as measured on the Biphasic Alcohol Effects Scale, (rs279858: P = 0.0046; rs6447493: P = 0.0023); both effects were in the opposite direction of previous findings. Carriers of the rs279858 C allele experienced greater stimulation from alcohol. Further inspection of the rs6447493 interaction did not support a pharmacogenetic effect. The effects of rs279858 (but not the other two SNPs) on items from a secondary outcome measure, the Drug Effects Questionnaire (DEQ), were significant. Higher ratings by individuals with the C allele were observed on the DEQ items 'feel the alcohol effect' (P < 0.001), 'like the alcohol effect' (P < 0.001) and feel 'high' (P < 0.001). CONCLUSION We did not find that the GABRG1 SNPs rs7654165 and rs6447493 moderated the effects of alcohol. Greater stimulatory and euphoric effects of alcohol in carriers of the rs279858 C allele may, in part, explain the previously reported association of this allele with AD.
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Affiliation(s)
- Albert J Arias
- Corresponding author: Department of Psychiatry, University of Connecticut Health Center, 263 Farmington Avenue, Farmington, CT 06030-1410, USA.
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Kerfoot K, Pittman B, Ralevski E, Limoncelli D, Koretski J, Newcomb J, Arias AJ, Petrakis IL. Effects of family history of alcohol dependence on the subjective response to alcohol using the intravenous alcohol clamp. Alcohol Clin Exp Res 2013; 37:2011-8. [PMID: 23895557 DOI: 10.1111/acer.12199] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2012] [Accepted: 05/05/2013] [Indexed: 12/01/2022]
Abstract
BACKGROUND Alcohol use disorders are well recognized to be common, debilitating, and the risk of developing them is influenced by family history (FH). The subjective response to alcohol may be determined familialy and related to the risk of developing alcoholism. The aim of this study was to evaluate differences between family history positive (FHP) and family history negative (FHN) individuals in their response to alcohol within the domains of subjective, coordination, and cognitive effects using an intravenous (IV) clamping method of alcohol administration. METHODS Two groups of healthy subjects, those with an FHP (n = 65) versus those who were FHN (n = 115), between the ages of 21 to 30, participated in 3 test days. Subjects were scheduled to receive placebo, low-dose ethanol (EtOH) (target breath alcohol clamping [BrAC] = 40 mg%), and high-dose EtOH (target BrAC = 100 mg%) on 3 separate test days at least 3 days apart in a randomized order under double-blind conditions. Outcome measures included subjective effects, measures of coordination, and cognitive function. RESULTS Both low- and high-dose alcohol led to dose-related stimulant and sedative subjective effects as measured the Biphasic Alcohol Effects Scale and subjective measures of "high" and "drowsy" measured on a visual analog scale. However, there were no effects of FH. Similar dose-related effects were observed on cognitive and coordination-related outcomes, but were not moderated FH. CONCLUSIONS Results from this study showed that healthy individuals responded to an IV alcohol challenge in a dose-related manner; however, there were no significant differences on subjective response, or on EtOH-induced impairment of coordination or cognition, between individuals with a positive FH for alcoholism and those with a negative FH. Results suggest that FH may not be a specific enough marker of risk, particularly in individuals who are beyond the age where alcohol use disorders often develop.
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Affiliation(s)
- Karin Kerfoot
- NIAAA Center for the Translational Neuroscience of Alcoholism and Department of Psychiatry , Yale University School of Medicine, New Haven, Connecticut; Department of Veterans Affairs , Alcohol Research Center, VA Connecticut Healthcare System (116-A), West Haven, Connecticut; Department of Psychiatry , University of Western Ontario, London, Ontario, Canada
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Kaminski BJ, Van Linn ML, Cook JM, Yin W, Weerts EM. Effects of the benzodiazepine GABAA α1-preferring ligand, 3-propoxy-β-carboline hydrochloride (3-PBC), on alcohol seeking and self-administration in baboons. Psychopharmacology (Berl) 2013; 227:127-36. [PMID: 23271191 PMCID: PMC3624026 DOI: 10.1007/s00213-012-2946-z] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/04/2012] [Accepted: 12/01/2012] [Indexed: 12/18/2022]
Abstract
RATIONALE The various α subtypes of GABAA receptors have been strongly implicated in alcohol reinforcement and consumption. OBJECTIVES The effects of the GABAA α1-preferring ligand, 3-propoxy-β-carboline hydrochloride (3-PBC), on seeking and self-administration responses were evaluated in two groups of baboons trained under a 3-component chained schedule of reinforcement (CSR). METHODS Alcohol (4 % w/v; n = 5; alcohol group) or a preferred nonalcoholic beverage (n = 4; control group) was available for self-administration only in component 3 of the CSR. Responses in component 2 provided indices of motivation to drink (seeking). 3-PBC (1.0-30.0 mg/kg) and saline were administered before drinking sessions under both acute and 5-day dosing conditions. RESULTS Repeated, and not acute, doses of 3-PBC significantly decreased total self-administration responses (p < 0.05), volume consumed (p < 0.05), and gram per kilogram of alcohol (p < 0.05) in the alcohol group. In the control group, 5-day administration of 3-PBC significantly decreased total self-administration responses (p < 0.05) but produced nonsignificant decreases in volume consumed. Within-session pattern of drinking was characterized by a high level of drinking in the first 20 min of the session for both groups, which was significantly (p < 0.05) decreased by all doses of 3-PBC (1.0-18.0 mg/kg) only in the alcohol group. In contrast, the first drinking bout in the control group was only reduced at the highest doses of 3-PBC (10.0 and 18.0 mg/kg). CONCLUSIONS The results support the involvement of the GABAA α1 subtype receptor in alcohol reinforcement and consumption.
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Affiliation(s)
- Barbara J. Kaminski
- Division of Behavioral Biology, Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, 5510 Nathan Shock Drive, Baltimore, MD, 21224
| | - Michael L. Van Linn
- Department of Chemistry and Biochemistry, University of Wisconsin-Milwaukee, Milwaukee, WI 53201
| | - James M. Cook
- Department of Chemistry and Biochemistry, University of Wisconsin-Milwaukee, Milwaukee, WI 53201
| | - Wenyuan Yin
- Department of Chemistry and Biochemistry, University of Wisconsin-Milwaukee, Milwaukee, WI 53201
| | - Elise M. Weerts
- Division of Behavioral Biology, Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, 5510 Nathan Shock Drive, Baltimore, MD, 21224
- Corresponding Author: Elise M. Weerts, Ph.D., Johns Hopkins Bayview Campus, Behavioral Biology Research Center, 5510 Nathan Shock Drive, Suite 3000, Baltimore, MD 21224, USA Tel.: 410-550-2781; Fax: 410-550-2780;
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Uhart M, Weerts EM, McCaul ME, Guo X, Yan X, Kranzler HR, Li N, Wand GS. GABRA2 markers moderate the subjective effects of alcohol. Addict Biol 2013; 18:357-69. [PMID: 22501025 DOI: 10.1111/j.1369-1600.2012.00457.x] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
Individual differences in subjective responses (SRs) to alcohol are moderated by genetic variants and may be risk factors for the development of alcohol use disorders. Variation in the GABA(A) α2 receptor subunit gene (GABRA2) has been associated with alcohol dependence (AD). Therefore, we examined whether individual differences in SRs, which reflect sensitivity to the effects of alcohol, are associated with variation in GABRA2. Sixty-nine healthy subjects (21-30 years) underwent a laboratory-based within-session cumulative oral alcohol dosing procedure, achieving a mean peak blood alcohol level of 100.4 mg/dl (standard error = 2.5). Subjective assessments were obtained throughout the session, including ascending and descending limbs of the alcohol curve. We genotyped single nucleotide polymorphisms (SNPs) across the chromosome 4 region spanning GABRA2 and analyzed the effect of genotype and haplotypes on subjective responses to alcohol. Population substructure was characterized through the use of ancestry informative markers. Individual SNP analysis demonstrated that carriers of the minor alleles for SNPs rs279858, rs279844, rs279845, rs279826, rs279828 and rs279836 had lower 'Negative' alcohol effects scores than individuals homozygous for the common allele at each SNP (P = 0.0060, P = 0.0035, P = 0.0045, P = 0.0043, P = 0.0037 and P = 0.0061, respectively). Haplotype effects of block 1 showed concordant results with SNPs in this block (P = 0.0492 and P = 0.0150 for haplotypes 1 and 4, respectively). The minor alleles for several of these SNPs have previously been associated with AD. Our findings provide further evidence that variation within GABRA2 is associated with attenuated negative responses to alcohol, a known risk factor for vulnerability to alcohol use disorders.
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Affiliation(s)
- Magdalena Uhart
- Department of Medicine, The Johns Hopkins University School of Medicine, Baltimore, MD, USA.
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Plawecki MH, Wetherill L, Vitvitskiy V, Kosobud A, Zimmermann US, Edenberg HJ, O'Connor S. Voluntary intravenous self-administration of alcohol detects an interaction between GABAergic manipulation and GABRG1 polymorphism genotype: a pilot study. Alcohol Clin Exp Res 2013; 37 Suppl 1:E152-60. [PMID: 22817768 PMCID: PMC4159724 DOI: 10.1111/j.1530-0277.2012.01885.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2011] [Accepted: 05/02/2012] [Indexed: 12/21/2022]
Abstract
BACKGROUND Operant responding paradigms quantify a subject's motivation for reward, but such studies employing ingested alcohol cannot assure the same incremental increase in brain exposure to alcohol across subjects because of substantial variability in absorption kinetics. We developed a human progressive ratio (PR) paradigm using the computer-assisted self-infusion of ethanol (CASE) system that overcomes such variability and conducted a pilot study to assess its utility for detecting an interaction of subjects' GABRA2 or GABRG1 genotype and pretreatment with 1 mg of lorazepam (LZ) vs. placebo on their willingness to work for alcohol rewards. METHODS Twenty healthy, nondependent drinkers, aged 21 to 27, were balanced on rs279871 and rs2350439 single nucleotide polymorphisms in the GABRA2 and GABRG1 genes, respectively. Subjects worked for alcohol, with water as an alternative reinforcer (AR), using a progressive schedule of a task that required constant attention and adapted to both fatigue and drug effects. Testing began 1 hour after pretreatment with 1 mg LZ or placebo in a crossover design. RESULTS The CASE system performed well, and the constant attention task was perceived as work by all subjects. GABRA2 homozygosity did not significantly predict either breakpoint or cumulative work, whereas a significant GABRG1 genotype by LZ pretreatment interaction for cumulative work was detected (p = 0.04). Breakpoint revealed a weak trend toward pretreatment drug effects (p = 0.11), and a somewhat stronger interaction of LZ pretreatment with GABRG1 genotype (p = 0.06). GABRG1 status revealed a more complex relationship with respect to motivation for alcohol with and without LZ pretreatment; AG and GG individuals worked more for alcohol under both pretreatment conditions, while AA individuals worked more for the AR. CONCLUSIONS The CASE PR paradigm shows promise as a laboratory method for use in drug development and phenotyping studies.
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Affiliation(s)
- Martin H Plawecki
- Department of Psychiatry, Indiana University School of Medicine, Indianapolis, Indiana 46202, USA
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Dixon CI, Walker SE, King SL, Stephens DN. Deletion of the gabra2 gene results in hypersensitivity to the acute effects of ethanol but does not alter ethanol self administration. PLoS One 2012; 7:e47135. [PMID: 23115637 PMCID: PMC3480382 DOI: 10.1371/journal.pone.0047135] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2012] [Accepted: 09/10/2012] [Indexed: 12/04/2022] Open
Abstract
Human genetic studies have suggested that polymorphisms of the GABRA2 gene encoding the GABAA α2-subunit are associated with ethanol dependence. Variations in this gene also convey sensitivity to the subjective effects of ethanol, indicating a role in mediating ethanol-related behaviours. We therefore investigated the consequences of deleting the α2-subunit on the ataxic and rewarding properties of ethanol in mice. Ataxic and sedative effects of ethanol were explored in GABAA α2-subunit wildtype (WT) and knockout (KO) mice using a Rotarod apparatus, wire hang and the duration of loss of righting reflex. Following training, KO mice showed shorter latencies to fall than WT littermates under ethanol (2 g/kg i.p.) in both Rotarod and wire hang tests. After administration of ethanol (3.5 g/kg i.p.), KO mice took longer to regain the righting reflex than WT mice. To ensure the acute effects are not due to the gabra2 deletion affecting pharmacokinetics, blood ethanol concentrations were measured at 20 minute intervals after acute administration (2 g/kg i.p.), and did not differ between genotypes. To investigate ethanol’s rewarding properties, WT and KO mice were trained to lever press to receive increasing concentrations of ethanol on an FR4 schedule of reinforcement. Both WT and KO mice self-administered ethanol at similar rates, with no differences in the numbers of reinforcers earned. These data indicate a protective role for α2-subunits, against the acute sedative and ataxic effects of ethanol. However, no change was observed in ethanol self administration, suggesting the rewarding effects of ethanol remain unchanged.
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Affiliation(s)
- Claire I. Dixon
- School of Psychology, University of Sussex, Brighton, United Kingdom
| | - Sophie E. Walker
- School of Psychology, University of Sussex, Brighton, United Kingdom
| | - Sarah L. King
- School of Psychology, University of Sussex, Brighton, United Kingdom
| | - David N. Stephens
- School of Psychology, University of Sussex, Brighton, United Kingdom
- * E-mail:
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Agrawal A, Verweij KJH, Gillespie NA, Heath AC, Lessov-Schlaggar CN, Martin NG, Nelson EC, Slutske WS, Whitfield JB, Lynskey MT. The genetics of addiction-a translational perspective. Transl Psychiatry 2012; 2:e140. [PMID: 22806211 PMCID: PMC3410620 DOI: 10.1038/tp.2012.54] [Citation(s) in RCA: 119] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/30/2012] [Accepted: 05/30/2012] [Indexed: 12/16/2022] Open
Abstract
Addictions are serious and common psychiatric disorders, and are among the leading contributors to preventable death. This selective review outlines and highlights the need for a multi-method translational approach to genetic studies of these important conditions, including both licit (alcohol, nicotine) and illicit (cannabis, cocaine, opiates) drug addictions and the behavioral addiction of disordered gambling. First, we review existing knowledge from twin studies that indicates both the substantial heritability of substance-specific addictions and the genetic overlap across addiction to different substances. Next, we discuss the limited number of candidate genes which have shown consistent replication, and the implications of emerging genomewide association findings for the genetic architecture of addictions. Finally, we review the utility of extensions to existing methods such as novel phenotyping, including the use of endophenotypes, biomarkers and neuroimaging outcomes; emerging methods for identifying alternative sources of genetic variation and accompanying statistical methodologies to interpret them; the role of gene-environment interplay; and importantly, the potential role of genetic variation in suggesting new alternatives for treatment of addictions.
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Affiliation(s)
- A Agrawal
- Department of Psychiatry, Washington University School of Medicine, Saint Louis, MO 63110, USA.
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Abstract
A large segment of the population suffers from addiction to alcohol, smoking, or illicit drugs. Not only do substance abuse and addiction pose a threat to health, but the consequences of addiction also impose a social and economic burden on families, communities, and nations. Genome-wide linkage and association studies have been used for addiction research with varying degrees of success. The most well-established genetic factors associated with alcohol dependence are in the genes encoding alcohol dehydrogenase (ADH), which oxidizes alcohol to acetaldehyde, and aldehyde dehydrogenase (ALDH2), which oxidizes acetaldehyde to acetate. Recently emerging genetic studies have linked variants in the genes encoding the α3, α5, and β4 nicotinic acetylcholine receptor subunits to smoking risk. However, the influence of these well-established genetic variants accounts for only a small portion of the heritability of alcohol and nicotine addiction, and it is likely that there are both common and rare risk variants yet to be identified. Newly developed DNA sequencing technologies could potentially advance the detection of rare variants with a larger impact on addiction risk.
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Affiliation(s)
- Jen-Chyong Wang
- Department of Psychiatry, School of Medicine, Washington University in St. Louis, St. Louis, MO 63110, USA.
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Cui WY, Seneviratne C, Gu J, Li MD. Genetics of GABAergic signaling in nicotine and alcohol dependence. Hum Genet 2012; 131:843-55. [PMID: 22048727 PMCID: PMC3746562 DOI: 10.1007/s00439-011-1108-4] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2011] [Accepted: 10/23/2011] [Indexed: 12/19/2022]
Abstract
Both nicotine and alcohol addictions are common chronic brain disorders that are of great concern to individuals and society. Although genetics contributes significantly to these disorders, the susceptibility genes and variants underlying them remain largely unknown. Many years of genome-wide linkage and association studies have implicated a number of genes and pathways in the etiology of nicotine and alcohol addictions. In this communication, we focus on current evidence, primarily from human genetic studies, supporting the involvement of genes and variants in the GABAergic signaling system in the etiology of nicotine dependence and alcoholism based on linkage, association, and gene-by-gene interaction studies. Current efforts aim not only to replicate these findings in independent samples, but also to identify which variant contributes to the detected associations and through what molecular mechanisms.
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Affiliation(s)
- Wen-Yan Cui
- State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
- National Key Laboratory of Protein and Plant Gene Research, College of Life Sciences, Peking University, Beijing, China
| | - Chamindi Seneviratne
- Department of Psychiatry and Neurobehavioral Sciences, University of Virginia, 1670 Discovery Drive, Suite 110, Charlottesville, VA 22911, USA
| | - Jun Gu
- National Key Laboratory of Protein and Plant Gene Research, College of Life Sciences, Peking University, Beijing, China
| | - Ming D. Li
- State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
- Department of Psychiatry and Neurobehavioral Sciences, University of Virginia, 1670 Discovery Drive, Suite 110, Charlottesville, VA 22911, USA
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Abstract
Pharmacogenetic analyses of treatments for alcohol dependence attempt to predict treatment response and side-effect risk for specific medications. We review the literature on pharmacogenetics relevant to alcohol dependence treatment, and describe state-of-the-art methods of pharmacogenetic research in this area. Two main pharmacogenetic study designs predominate: challenge studies and treatment-trial analyses. Medications studied include US FDA-approved naltrexone and acamprosate, both indicated for treating alcohol dependence, as well as several investigational (and off-label) treatments such as sertraline, olanzapine and ondansetron. The best-studied functional genetic variant relevant to alcoholism treatment is rs1799971, a single-nucleotide polymorphism in exon 1 of the OPRM1 gene that encodes the μ-opioid receptor. Evidence from clinical trials suggests that the presence of the variant G allele of rs1799971 may predict better treatment response to opioid receptor antagonists such as naltrexone. Evidence from clinical trials also suggests that several medications interact pharmacogenetically with variation in genes that encode proteins involved in dopaminergic and serotonergic neurotransmission. Variation in the DRD4 gene, which encodes the dopamine D(4) receptor, may predict better response to naltrexone and olanzapine. A polymorphism in the serotonin transporter gene SLC6A4 promoter region appears related to differential treatment response to sertraline depending on the subject's age of onset of alcoholism. Genetic variation in SLC6A4 may also be associated with better treatment response to ondansetron. Initial pharmacogenetic efforts in alcohol research have identified functional variants with potential clinical utility, but more research is needed to further elucidate the mechanism of these pharmacogenetic interactions and their moderators in order to translate them into clinical practice.
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Affiliation(s)
- Albert J. Arias
- Department of Psychiatry, Yale University School of Medicine, New Haven, CT, USA,VA Connecticut Healthcare System, West Haven, CT, USA
| | - R. Andrew Sewell
- Department of Psychiatry, Yale University School of Medicine, New Haven, CT, USA,VA Connecticut Healthcare System, West Haven, CT, USA
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Borghese CM. Alcohol Dependence and Genes Encoding α2 and γ1 GABAA Receptor Subunits: Insights from Humans and Mice. Alcohol Res 2012; 34:345-53. [PMID: 23134051 PMCID: PMC3860398] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
One approach to identifying the causes of alcoholism, particularly without crossing ethical boundaries in human subjects, is to look at the person's genome (and particularly at the variations that naturally arise in the DNA) to identify those variations that seem to be found more commonly in people with the disease. Some of these analyses have focused on the genes that encode subunits of the receptor for the brain chemical (i.e., neurotransmitter) γ-aminobutyric acid (GABA). Different epidemiological genetic studies have provided evidence that variations in certain GABAA receptor (GABAA-R) subunits, particularly subunits α2 and γ1, are correlated with alcohol dependence. Manipulations of these genes and their expression in mice and rats also are offering clues as to the role of specific GABAA-Rs in the molecular mechanisms underlying alcoholism and suggest possibilities for new therapeutic approaches.
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Heilig M, Goldman D, Berrettini W, O'Brien CP. Pharmacogenetic approaches to the treatment of alcohol addiction. Nat Rev Neurosci 2011; 12:670-84. [PMID: 22011682 PMCID: PMC3408029 DOI: 10.1038/nrn3110] [Citation(s) in RCA: 171] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Addictive disorders are partly heritable, chronic, relapsing conditions that account for a tremendous disease burden. Currently available addiction pharmacotherapies are only moderately successful, continue to be viewed with considerable scepticism outside the scientific community and have not become widely adopted as treatments. More effective medical treatments are needed to transform addiction treatment and address currently unmet medical needs. Emerging evidence from alcoholism research suggests that no single advance can be expected to fundamentally change treatment outcomes. Rather, studies of opioid, corticotropin-releasing factor, GABA and serotonin systems suggest that incremental advances in treatment outcomes will result from an improved understanding of the genetic heterogeneity among patients with alcohol addiction, and the development of personalized treatments.
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Affiliation(s)
- Markus Heilig
- Laboratory of Clinical and Translational Studies, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, Maryland 20892, USA. markus.heilig@mail. nih.gov
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