Gamma-amino butyric acid (GABA) is the major inhibitory neurotransmitter in the human central nervous system. Previous research has suggested that GABA is involved in many of the neurochemical pathways affecting alcohol use, abuse and dependence. A study in the January issue of Alcoholism: Clinical & Experimental Research, using family-based analyses to examine the role of a cluster of GABAA receptor genes on chromosome 15q, becomes one of the first to demonstrate a consistent association between alcohol dependence and GABAA receptor gene GABRG3.
"There are several lines of evidence that suggest that GABA is involved in alcohol use and abuse," explained Danielle M. Dick, assistant professor in the department of psychiatry at Washington University School of Medicine and first author of the study. "For example, chemicals that increase the activity of GABAA receptors tend to accentuate the behavioral effects of alcohol, such as motor incoordination, sedation, and withdrawal signs, while chemicals that block GABAA receptors lessen these effects."
For this study, Dick and her colleagues decided to focus on GABAA receptor genes on chromosome 15q because of earlier findings from the multi-site Collaborative Study on the Genetics of Alcoholism (COGA) "suggesting a gene influencing alcoholism-related phenotypes in this area," she said.
Tapping into the COGA data once again, researchers tested for an association between alcohol dependence and three chromosome 15q GABAA receptor genes GABRA5, GABRB3, and GABRG3 in 2,282 individuals from 262 alcoholic families.