Cocaine uptake is decreased in the brain of detoxified cocaine abusers.

Binding of [11C]cocaine in brain was measured with positron emission tomography in 12 detoxified cocaine abusers and in 20 controls to evaluate if there were changes in cocaine binding and in dopamine (DA) transporter availability associated with chronic cocaine use. Nine controls and 10 cocaine abusers had an additional scan with [18F]N-methylspiroperidol to measure dopamine D2 receptors. Cocaine abusers had significantly lower uptake of [11C]cocaine in brain (6.2 +/- 1% dose/cc tissues) than controls (7.7 +/- 2%). The distribution volumes (DV) for [11C]cocaine were reduced in basal ganglia (BG), cortex, thalamus, and cerebellum (CB) of cocaine abusers. However there were no differences in the ratio of the DV in BG to that in CB, which is an estimate of DA transporter availability. Values for DA D2 receptor availability were decreased in cocaine abusers and did not correlate with estimates of dopamine transporter availability. In summary, detoxified cocaine abusers showed decreased uptake of cocaine in brain but did not show changes in DA transporter availability.