A variant of a gene involved in communication among brain cells has a direct influence on alcohol consumption in mice, according to a new study by US scientists.

If approved in human beings, the finding may lead to new opportunities for developing drugs to treat alcohol dependence.

Known as Grm7, the gene encodes a receptor subtype that inhibits the release of glutamate and other neurotransmitter molecules that brain cells use to communicate with one another.

Researchers led by Csaba Vadasz from the New York University identified a gene variant that reduces the abundance of Grm7 messenger RNA (mRNA) in brain tissue. mRNA is the molecular intermediate between a gene and its protein product.

Mice that possess this gene variant drink more alcohol than the mice with higher brain levels of Grm7 mRNA do. It is not known yet whether a similar gene variant, with a similar effect on alcohol consumption, exists in humans.

Scientists have long known that genes account for a significant proportion of the risk of alcoholism.

However, the fact that there are multiple such genes that interact with each other and with multiple environmental factors to influence drinking behaviour has hampered studies aimed at isolating individual genes.

To overcome these difficulties, Vadasz and his colleagues applied a variety of genetic and analytic techniques to animals with a nearly identical genetic background to identify a chromosomal region, and ultimately the Grm7 gene, associated with alcohol preference.