The latest progress is being spurred by new insights into how the brain functions under drug dependency. Md. He is launching trials of 35 candidate drugs this year, trying to turn the boom in neuroscience into precise molecular weapons to block the high and ease the craving for cocaine. Many addiction researchers say the new-drug push is essential. Cocaine use has broadened since the 1980s, with a potent, smokable form of cocaine now marketed at a fraction of its former price. Cocaine affects many kinds of brain cells, including those of the dopamine, serotonin and norepinephrine systems.
Dopamine alone has five known brain receptors.
They also include older drugs being redeployed. Despite mixed results in prior trials, Dr. Leshner believes the drugs could work when coupled with cognitive behavioral therapy. Propranolol, a beta-blocker drug known to reduce stage fright, is currently being tested in a study by Dr. O'Brien's group at Penn to see if it can ease the symptoms of stress leading addicts to relapse. A D1 antagonist, is being developed by Schering-Plough Corp., Madison, N.J., and is in early clinical trials. It is an attempt to block dopamine's d1 receptor, blunting the drug's effects and helping prevent relapse.