GENETIC FACTORS LINKED TO DRUG ADDICTION - STUDY

LONDON (Reuters) - Genetic factors may influence a person's vulnerability
to drug addiction, U.S. researchers said Wednesday.

Dr Rene Hen and colleagues at Columbia University in New York found that
mice lacking an important brain protein had a stronger response and
sensitivity to cocaine than normal mice.

The finding could help scientists better understand the molecular basis of
human drug addiction and how to counteract it.

In a report in the scientific journal Nature, Hen described how mice
without the 1-B receptor for the neurotransmitter serotonin were more
susceptible to the addictive properties of cocaine.

The loss of the receptor seemed to have caused long-term changes in the
brains of the mutant mice that were similar to changes in normal mice that
had become sensitized to cocaine.

``These results provide the first definitive evidence for the involvement
of a specific serotonin receptor in processes that may underlie cocaine
addiction,'' Francis White of Finch University of Health Sciences in
Chicago said in an accompanying commentary.

The addictive elements of cocaine and other drugs are connected with the
release of another neurotransmitter, called dopamine, which controls
motivation and feelings of pleasure in the brain.

Serotonin influences mood and appetite and can interfere with dopamine to
modify the effects of drugs.

``Results from these experiments indicated that certain effects of cocaine
could be mimicked by stimulating the serotonin-1B receptors, and that
blocking the receptors might reduce the effects of cocaine,'' White said.

During the experiments, the mice were trained to self-administer cocaine by
pressing on a lever. The researchers found that mice lacking the 1-B
receptor took twice as much cocaine as the normal mice.

Hen also noted that the mutant mice were more impulsive, a characteristic
that is often associated with drug abuse.

Checked-by: Mike Gogulski