125I] beta-CIT-FE and [125I] beta-CIT-FP are superior to [125I] beta-CIT for dopamine transporter visualization: autoradiographic evaluation in the human brain

The binding of the three dopamine transporter radioligands (125I] beta-CIT, 125I] beta-CIT-FE, and 125I] beta-CIT-FP) was studied using whole-hemisphere autoradiography on postmortem human brains. The autoradiograms revealed an intense and homogeneous labeling of the nucleus caudatus and putamen but also to varying extent to serotonergic and noradrenergic transporters of neocortex and thalamus. The order of specificity estimated (striatum over neocortex ratios) was beta-CIT-FP > beta-CIT-FE > > beta-CIT, suggesting that beta-CIT-FE and beta-CIT-FP should be preferred for in vivo studies of the dopamine transporter in the human brain.