Experiments with mice confirms that drinking low to moderate amounts of alcohol — but not high amounts — releases pain-killing "feel-good" substances in the brain called endorphins.

"Drinking low amounts of alcohol," Dr. Christina Gianoulakis commented to Reuters Health, "is associated with mild euphoria, decreased anxiety and a general feeling of well being, while drinking high amounts of alcohol is associated with sedative, hypnotic effects and often with increased anxiety."

Added Gianoulakis, who is a professor of psychiatry and physiology at McGill University in Montreal: "Consumption of high amounts of alcohol not only will fail to increase the release of endorphins and produce a feeling of well being, but may stimulate other systems in the brain that may lead to the development of anxiety and depression."

In their study, researchers injected rats with either saline or different amounts of alcohol and tracked the response of endorphins. They found that low to moderate but not high doses of alcohol increased the release of beta-endorphin in the midbrain/Ventral Tegmental Area (VTA) — one of the regions of the brain known to be important for producing the rewarding effect of alcohol.

Results of the study, available online now, will be published in the June issue of Alcoholism: Clinical and Experimental Research.

"Since drinking only low amounts of alcohol will increase endorphin release and produce pleasant effects, if after consumption of about two drinks of alcohol an individual does not experience the pleasant effects of alcohol, he or she should stop drinking," Gianoulakis advised.

Dr. Dzung Anh Le, of the Center for Addiction and Mental Health at the University of Toronto who was not involved in the study, said the new findings could have implications for treatment of alcoholism.

"While current alcoholism treatment blocks opioids in a nonspecific fashion, this research suggests that a more targeted approach would be more beneficial," Le noted in a statement. "Researchers now have to specifically target endorphins in the VTA to see if it really does affect alcohol abuse and craving."

SOURCE: Alcoholism: Clinical and Experimental Research, June 2009.