In vivo voltammetric characterization of low affinity striatal dopamine uptake: drug inhibition profile and relation to dopaminergic innervation density.

Electrical stimulation of the median forebrain bundle evoked dopamine release in the ipsilateral striatum which was monitored with high-speed cyclic voltammetry. After stimulation, the extracellular concentration of dopamine fell due to uptake in a biphasic manner, showing zero-order and first-order components. The zero-order phase corresponded to a Vmax of 42.8 +/- 1.8 nmol/min/g tissue. The uptake system could be blocked by D-amphetamine, methylphenidate and nomifensine, but not by benztropine, amfonelic acid or mazindol. The density of uptake sites showed a correlation with the density of striatal dopamine innervation.