Gene mutation makes rats light drinkers

A genetic variation that drastically lowers rats' tolerance of alcohol may also explain why some people become drunk after just one beer, US scientists say. Researchers at the University of California in Los Angeles (UCLA) have worked out how a naturally occurring gene mutation affects rats' brains so that they become 'acutely intoxicated' after the equivalent of one alcoholic drink. The findings, published online in the journal Nature Neuroscience, suggest that tolerance levels to alcohol may also be genetically wired in people, say the scientists.

Alcohol interferes with how brain cells communicate with one another, causing problems with co-ordination, memory and loss of inhibitions. The UCLA team has discovered that rats with a low tolerance to alcohol have an altered version of a gene that makes a GABA (gamma aminobutyric acid) receptor - a protein that interacts with a chemical crucial to brain cell communication. The mutation makes the GABA receptors more responsive to very low levels of alcohol, which in turn slows the brain cells' activity and ability to communicate.

The researchers say their findings could eventually help identify children and adults at high risk of becoming dependent on alcohol, which could allow them to make 'an informed decision' about whether to drink. The study could also lead to new drugs that target alcohol-sensitive GABA receptors, providing better treatments for alcohol poisoning and addiction. Author Richard Olsen said: 'If we understand the action of alcohol at the cellular and molecular level, it is helpful in treating the harmful effects that alcohol may have'.