INCREASED MU-OPIOID RECEPTOR-BINDING DETECTED BY PET IN COCAINE-DEPENDENT MEN IS ASSOCIATED WITH COCAINE CRAVING

The endogenous opioid system has been recently implicated in the reinf orcing actions of cocaine and other addictive drugs. In this study we examined mu opioid receptor binding in ten cocaine-dependent men and s even nonaddicted controls using positron emission tomography and [C-11 ]carfentanil. Mu opioid binding was increased in several brain regions of the cocaine addicts studied 1-4 days after their last use of cocai ne. Binding was positively correlated with the severity of cocaine cra ving experienced at the time. The upregulation of mu opioid receptor b inding persisted after 4 weeks of monitored cocaine abstinence. These findings demonstrate for the first time the involvement of the endogen ous opioid system in cocaine dependence and cocaine craving in living human subjects.