DECREASING STRIATAL 6-FDOPA UPTAKE WITH INCREASING DURATION OF COCAINE WITHDRAWAL

It has been hypothesized that a decrease in dopaminergic presynaptic a ctivity during abstinence or withdrawal is related to relapse in cocai ne-dependent subjects (Dackis and Gold 1985; Markou and Koob 1991). Th is study measured striatal 6-fluorodopa (6-FDOPA) uptake, and index of dopaminergic presynaptic activity, using positron emission tomography (PET) in 11 drug-free cocaine addicts compared to eight normal subjec ts. Middle abstinence cocaine addicts (n = 5, off cocaine 11-30 days) had significantly lower striatal 6-FDOPA uptake compared to normal con trols or early abstinence cocaine addicts (n = 6, off cocaine 1-10 day s). The cocaine-dependent subjects (n = 11) showed a significant negat ive correlation between days off cocaine and striatal 6-FDOPA uptake. The results suggest that during abstinence from cocaine there is a del ayed decrease in dopamine terminal activity in the striatum. (C) 1997 American College of Neuropsychopharmacology. Published by Elsevier Sci ence Inc.