One injection of cocaine produces a long-lasting increase in [3H]-dopamine release.

A single cocaine exposure has been reported to sensitize animals to the behavioral effect of subsequent cocaine administration for up to one week. We now report that a single injection of cocaine results in an augmentation in amphetamine-induced release of tritium from rat striatal slices preloaded with [3H]-dopamine. The augmentation appears within 24 hr and persists for at least 2 weeks after injection. This increase in release may result in increased synaptic concentrations of dopamine possibly caused by a change in the membrane transporter for dopamine. Increased dopaminergic synaptic transmission could explain behavioral sensitization.