Chronic use of nicotine can reinforce the rewarding effects of alcohol

Dec 2 2006

When sober alcoholics are tempted to fall off the wagon, the same receptor is stimulated as is activated by nicotine in their brain.

This has been demonstrated in a doctoral dissertation at the Sahgrenska Academy at Göteborg University in Sweden. The discovery may lead to new treatment for alcohol abuse.

The connection between nicotine and alcohol has been known for some time.

"Alcoholism is ten times stronger among smokers than among non-smoker, and this connection between alcohol and nicotine is not just because many people smoke at parties," says Elin Löf.

By studying the brains of rats, the research team has found several biological explanations.

When sober alcoholics find themselves in an environment that reminds them of what it was like to drink, they can easily be tempted to drink again. The studies show that the craving for alcohol is then controlled by the same mechanisms that nicotine uses to stimulate the brain. In both cases the brain's reward system is stimulated via receptors on the surface of nerve cells that are called nicotine receptors.

"Drugs that affect the proteins that control the effects of nicotine ought to be able to help former alcoholics stay sober. It should be a mild drug that has a low level effect on other behaviors that are controlled by these nicotine receptors," says Elin Löf.

A drug that functions according to that principle was recently launched by an international pharmaceutical company as an aid to quitting smoking.

Both smokers and alcoholics often experience a craving for sweets when they have abstinence problems. The studies show that conditioned craving for sweets is also conveyed via nicotine receptors.

"In other words, a future drug that impacts nicotine receptors ought to be able to help curb the hankering for sweets. This is an important discovery, since weight gain is a common reason that former smokers start smoking again," explains Elin Löf.

The findings also show that chronic use of nicotine can reinforce the rewarding effects of alcohol. At the same time, nicotine appears to decrease the sleep-inducing effects of alcohol.

Title of dissertation: Conditional and non-conditional reward-related responses to alcohol-nicotinic mechanisms.