Electrophysiological evaluation of the time-course of dopamine uptake inhibition induced by intravenous cocaine at a reinforcing dose

Our data confirm that cocaine at low, reinforcing doses inhibits DA uptake, resulting in potentiation of DA-induced neuronal inhibitions, but they suggest that this effect is relatively weak and delayed from the time of i.v. injection. These slow and prolonged effects of i.v. cocaine on DA-induced neuronal responses are consistent with previous binding and our electrochemical evaluations of DA uptake, presumably reflecting the total time necessary for i.v.-delivered cocaine to reach brain microvessels, cross the blood-brain barrier, passively diffuse within brain tissue, interact with the DA transporters, and finally inhibit DA uptake.