Rat striatal synaptosomes showed a reduced capacity to generate a membrane potential after being exposed to methamphetamine (METH) for 1 h. As a consequence, the dopamine (DA) synaptosomes were impeded in their electrogenic-dependent reuptake of dopamine. The capacity for METH-exposed nerve terminals to generate a membrane potential may contribute to the ability of METH to destroy dopaminergic neurons. DA uptake inhibitors (DAUIs) were found to counteract the METH-induced decrease in synaptosomal [3H]DA Vmax by stablizing METH-induced reductions in PMP. Because DAUIs showed the same effects as a Na+-channel blocker, DAUIs may prevent METH-induced destruction of dopaminergic neurons by raising plasma membrane potential.