Increased dopamine release from rat striatal slices by inhibitors of GABA-aminotransferase

The effects were examined of two inhibitors of GABA-aminotransferase, amino-oxyacetic acid (AOAA) and RMI-71645-16, on depolarization-induced (30 mM K+) dopamine (DA) release from rat striatal slices. When added to the medium, these drugs increased the release of radiolabeled DA, either accumulated by high-affinity uptake or synthesized from 14C-tyrosine. AOAA did not modify the release of 14C-acetylcholine from striatal slices or 3H-noradrenaline from cortical slices. Moreover, 3H-DA release from substantia nigra was not affected. The data suggest the possibility that the effects of GABA-T inhibitors on striatal DA release are mediated by intrinsic GABA-ergic neurons.