July 3, 2008


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AKINSO: Scientists have identified a mechanism in the brain that helps to explain why craving for cocaine, and the risk of relapse, seems to increase in the weeks and months after drug use has stopped. It has to do with cues.

VOCCI: We think there are a number of things both internal and external that trigger craving.

AKINSO: Dr. Frank Vocci is the Director of the Division of Pharmacotherapies and Medical Consequences of Drug Abuse at the National Institute on Drug Abuse.

VOCCI: Also with cocaine, cocaine primes itself.  So the old George Carlin joke was—“what does cocaine make you feel like?” And the answer is it makes you feel like taking more cocaine.

AKINSO: In a NIDA study, using rats, researchers demonstrated that after prolonged withdrawal from cocaine use, there is an increase in the number of proteins called AMPA glutamate receptors in a brain region which deals with motivation and reward. Exposure to environmental cues, such as people places and things, can trigger drug craving, often leading to relapse. Dr. Vocci talks about the long term implications of the findings.

VOCCI: The findings suggest two things.  One is that there are downstream effects of taking cocaine that occurred during cocaine abstinence. And that if we want to keep people from relapsing; what we have to do is to somehow modulate that effect. Now we can modulate that effect with an AMPA antagonist. And there are AMPA antagonists that are being developed as drugs. And the AMPA antagonist, some of them are being developed as anti-epileptic drugs; but they can also be evaluated in substance dependence to.

AKINSO: AMPA antagonists are drugs which help block or dampen AMPA receptors. Dr. Vocci says that the findings also suggest that medications could be developed to block atypical AMPA receptors in the reward and motivation area of the brain, thus reducing cocaine and other drug cravings. This is Wally Akinso at the National Institutes of Health, Bethesda, Maryland.