Enhancement in dopamine uptake and release induced by monosodium L-glutamate from caudate nucleus under in vitro conditions.

L-Glutamate has an excitatory and cytotoxic effect on the central nervous system. It was shown previously that norepinephrine and dopamine uptake and release were affected by in vivo administration of glutamate to adult rats. The kinetic parameters, Km and Vmax of [14C]DA uptake and release were measured on synaptosomal and slices from caudate nucleus under in vitro conditions at different glutamate concentrations. Results showed an important increase in [14C]DA uptake on synaptosomal (> 100%) and slices by lower glutamate concentrations, the affinity for transport system was increased (100%) and its release of high potassium evoked was also increased at 0.5 microM of glutamate. The results suggest the possibility that glutamate may modify DA uptake and release interacting with the DA transporter complex at the synaptic level.