PET measures of amphetamine-induced dopamine release in ventral versus dorsal striatum

Regional differences in dextroamphetamine (AMPH)-induced dopamine (DA) rele ase in the baboon striatum were assessed using positron emission tomographi c (PET) measures of [C-11] raclopride specific binding to DA D2/D3 receptor s acquired before and after AMPH administration. The magnitude of the reduc tion in [C-11]raclopride binding, following AMPH administration, was two-fo ld greater in the anteroventral striatum (comprised of ventral caudate, ant eroventral putamen, and nucleus accumbens) than the dorsal striatum (dorsal caudate) A simulation study demonstrated that any potential biases due to resolution (partial volume) and alignment effects were significantly smalle r than the magnitude of the observed results. These regional differences in the sensitivity to AMPH are compatible wit microdialysis evidence in rats indicating that the magnitude of DA release in response to AMPH concentrati ons in the range tested is greater in ventral than dorsal striatal regions. Post hoc tests involving measures in other striatal regions showed that th e baseline DA D2/D3 binding was highest and the correlation between AMPH do se and change in [C-11]raclopride binding most significant in the putamen. [Neuropsychopharmacology 21:694-709, 1999] (C) 1999 American College of Neu ropsychopharmacology. Published by Elsevier Science Inc.