A drug primarily used to help people quit smoking may also reduce cocaine addiction, based on recent tests on rats.
"This research opens a new approach to the treatment of cocaine abuse, which has been resistant to treatment in general," said Jed Rose, chief of the Medical Center's Nicotine Research Program.
Mecamylamine, which has been available for nearly half a century, was originally used to treat high blood pressure and has been known to help smokers quit.
Currently, the drug is under Food and Drug Administration review as a treatment for both smoking and Tourette's syndrome in children.
Mecamylamine works by blocking nicotonic receptors in the brain that would normally release dopamine, the primary chemical involved in generating feelings of pleasure.
An addicted individual's desire for cocaine is weakened when the drug cannot produce any feeling of pleasure in the brain.
Nicotine, cocaine and alcohol are just a few of the drugs that increase dopamine in the brain. Mecamylamine's presence may affect the pleasure-inducing qualities of other drugs, including cocaine.
"[Mecamylamine] indirectly affects the system that cocaine normally stimulates," explained Edward Levin, lead researcher and associate professor of psychiatry and behavioral science.
A paper about his research on the topic is currently being reviewed by several journals in the field.
Levin predicts that this research will pave the way for the discovery of new addiction-fighting drugs that will reduce the side effects of treatment.
"The results of this study can be used to find and develop even better antagonists that are more specific in targeting the sub-receptors directly stimulated in drug addiction," he said.
Levin and his colleagues observed rats that were injected with varying concentrations of mecamylamine. Previously, the rats developed a cocaine addiction by learning to press levers to get injections of cocaine.
The study closely models human behavior because people also self-administer their cocaine.
This research may also open new doors to identifying other ways to ease cocaine addiction.
"Through this research, we can find and understand the specific mechanism in the brain that can be exploited for treatment," said Dr. Paul Sanberg, the University of South Florida's director of neurosurgical research. "[Mecamylamine] increases the arsenal available to treat this addiction, which is an important avenue to provide addicts."
Levin observed an average 40 to 50 percent reduction in the number of times the mecamylamine-injected rats pressed the lever for cocaine. Concurrent tests were also conducted to ensure that the administered mecamylamine was not affecting food consumption and was specifically targeting drug enforcement.
These findings may demonstrate mecamylamine's ability to curb cocaine cravings.
The Medical Center study was funded by a grant from the National Institutes of Health.
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