Studies of mice found that, like humans, 15 percent of mice showed a preference for alcohol. The researchers asked mice to choose sugar yglycethane and alcohol, and then compared alcoholics with sugar-addicted mice to find differences in the active genes in their brains. They focused on six brain regions thought to be associated with addiction, five of which found no difference. But in the sixth region, they found the difference.
Differences exist in the amygdala region. The amygdala is an almond-shaped region of the brain located deep in the brain, which is closely related to emotional processing.
When Ogil looked at the amygdala of alcohol-addicted rats, he found that several genes were abnormally inactive, all of which were associated with a chemical called GABA. GABA is a neurotransmitter released by the brain that can make people feel dangerous and anxious. Some neurons produce and release GABA, which prevents adjacent neurons from excitation.
Once this process is complete, the neurons that produce GABA use an enzyme called GAT3 to recycle the molecule. But in the amygdala of alcoholic samaritans, the genetic activity that produces GAT3 is much lower, at half normal levels, so GAB A gathers around neighboring neurons, causing them to become abnormally inactive. Reducing the GAT3 levels of sugar-addicted mice can turn them into alcoholic sage.