Scientists from the University of Saskatchewan say that a synthetic peptide can be used to block a molecule that works to activate the dopamine system in the brain, perhaps opening a new pathway for research into a drug that can prevent addiction.

The Saskatoon Star Phoenix reported Feb. 13 that researchers found that the synthetic peptide, called Tat-3L4F, prevented addiction in rats by disrupting the action of the molecule PTEN, which helps spark the pleasure centers of the brain. The tests involved marijuana and nicotine.

"Our finding opens up a new window for the potential use of our peptide for the treatment of drug addiction," said co-author Xia Zhang of the University of Saskatchewan. Researchers from the University of Toronto and Vanderbilt University Medical Center in Tennessee also took part in the study.

One potential downside of such a treatment approach, however, is that it could prevent users from experiencing pleasure from causes other than drug use. "They may be blocking normal, natural positive-rewarding things like food and sex," said Marvin Krank, a psychology professor at the University of British Columbia at Okanagan. "By suppressing the reward system, some of these drugs induce things like depression, inactivity and so on."

The research appears in the March 2006 issue of Nature Medicine.