by Angela Spivey

Psychologists and medical researchers at the Center for Alcohol Studies investigate the most abused drug of all. Here is one recent finding — a biochemical link between alcohol and food.

To understand alcohol, some scientists are looking to its kissing cousin — food.

Both beers and bon-bons contain calories. And both bring pleasure, until they're consumed to excess.

Maybe you've heard about hormones or proteins in the body that control food intake — leptin, for example, which, when given to mice, makes them lose weight. Some scientists, including Todd Thiele, assistant professor in the Department of Psychology and in the Bowles Center for Alcohol Studies, are taking a second look at these substances. "We should take advantage of these compounds and see if they may also regulate alcohol drinking," he says.

Alcohol, Thiele explains, is a "messy drug." Unlike heroin and other opiates, it doesn't act on one specific spot in the brain. Alcohol produces an all-purpose buzz by working on many different systems. It affects both opiate signaling and dopamine signaling. And it's also known to work on another network of neurotransmitters and receptors — the GABA (gamma-aminobutyric acid) system, which plays a role in panic, anxiety, and stress. So it's not far-fetched to think that booze could also push some of the same buttons as food.

Thiele has been studying a couple brain-signaling proteins that are known to regulate food intake. Like other brain chemicals, he says, these "ingestive neuropeptides" are substances that send messages between neurons. But they're different because they are bigger proteins, and they don't act alone. For example, one of these proteins, neuropeptide Y, is secreted in the brain at the same time as the chemical dopamine and probably influences its action.

Most recently, Thiele has been using mice to study a group of neuropeptides called the melanocortins. With a single injection of a substance that mimics the effects of melanocortins, Thiele reduced alcohol drinking in the mice for up to two days. The substance also reduced their food intake. Then Thiele conducted the same experiment, but first he gave the mice a drug that blocks certain receptors for the melanocortins. This time, the melanocortin mimic had no effect. That suggests to him that the melanocortins reduce alcohol drinking because they are acting specifically on a brain receptor, not just because they are making the animal feel sick or sleepy.

Neuropeptide Y seems to have a less straightforward effect. It reduces alcohol drinking but increases food intake. Since this neuropeptide also reduces anxiety in mice, Thiele speculates that it could be reducing alcohol intake by working on emotional pathways, and that it increases food intake by acting on a pathway that controls the need for calories. "It's complicated," he says.

Thiele stresses that many of these findings are preliminary and that there's much more work to be done. He wants to find out, for example, exactly which receptors these substances are targeting.

"When you're talking about developing drugs to treat alcoholism, you want a compound that specifically targets the important receptor, and not all receptors," Thiele says. "This is a relatively new area of study."

Angela Spivey is associate editor of Endeavors magazine.