The l-amino acid carrier inhibitor 2-aminobicyclo[2.2.1]heptane-2-carboxylic acid (BCH) reduces l-dopa-elicited responses in dopaminergic neurons of the substantia nigra pars compacta

We have observed that BCH reduced, in a concentration-dependent manner, the membrane hyperpolarization/outward current caused by l-dopa. Interestingly, the actions of dopamine were not changed by this System L inhibitor, suggesting that the reducing effects on l-dopa are not due to a BCH-induced unspecific block of dopamine-mediated events. Therefore, our electrophysiological data that an l-type amino acid carrier, possibly System L, is involved in the transport of l-dopa into dopaminergic neurons.