Fake bar used to test drug designed to discourage drinking

WASHINGTON -- The tequila sure looks real, so do the beer taps. Inside the hospital at the National Institutes of Health, researchers are testing a possible new treatment to help heavy drinkers cut back -- using a replica of a fully stocked bar.

The idea: Sitting in the dimly lit bar-laboratory should cue the volunteers' brains to crave a drink, and help determine if the experimental pill counters that urge.

True, there's no skunky bar odor; these bottles are filled with colored water. The real alcohol is locked in the hospital pharmacy, ready to send over for the extra temptation of smell -- and to test how safe the drug is if people drink anyway.

"The goal is to create almost a real-world environment, but to control it very strictly," said lead researcher Dr. Lorenzo Leggio, who is testing how a hormone named ghrelin that sparks people's appetite for food also affects their desire for alcohol, and if blocking it helps.

Amid all the yearly resolutions to quit, alcohol use disorders affect about 17 million Americans, and only a small fraction receives treatment. There's no one-size-fits-all therapy, and the NIH is spurring a hunt for new medications that target the brain's addiction cycle in different ways -- and to find out which options work best in which drinkers.

"Alcoholics come in many forms," explained Dr. George Koob, director of NIH's National Institute of Alcohol Abuse and Alcoholism, which has published new online guides, at www.niaaa.nih.gov, explaining who's at risk and what can help.

Genes play a role in who's vulnerable to crossing the line into alcohol abuse. So do environmental factors, such as getting used to drinking a certain amount, not to mention how your brain's circuitry adapts.

Three drugs are approved by the Food and Drug Administration to treat alcohol abuse. One, naltrexone, blocks alcohol's feel-good sensation by targeting receptors in the brain's reward system -- if people harbor a particular gene. The anti-craving pill acamprosate appears to calm stress-related brain chemicals in certain people. The older Antabuse works differently, triggering nausea and other aversive symptoms if people drink.

Back in NIH's bar lab, one of about a dozen versions around the country, the focus is on ghrelin, the hormone produced in the stomach that controls appetite via receptors in the brain. It turns out there's overlap between receptors that fuel overeating and alcohol craving in the brain's reward system, explained Leggio.

In a study published this fall, his team gave 45 heavy-drinking volunteers different doses of ghrelin, and their urge to drink rose along with the extra hormone.

Now Leggio is testing whether blocking ghrelin's action also blocks those cravings, using an experimental Pfizer drug originally developed for diabetes but never sold. The main goal of this first-step study is to ensure mixing alcohol with the drug is safe.