Acute motor effects of N-methyl-D-aspartic acid and kainic acid applied focally to mesencephalic dopamine cell body regions in the rat.

Bilateral application of N-methyl-D-aspartate (NMDA) and kainic acid to the substantia nigra, pars compacta (SNc) and the ventral tegmental area (VTA) induced enhanced motor responses in the rat. A greater locomotor response was elicited from the VTA; sniffing was also observed following SNc injections. Both motor activities were blocked by systemic fluphenazine. Application of NMDA and kainate to the substantia nigra pars reticulata caused sedation and catalepsy. The experiments illustrate a dual motor response for excitatory amino acids when applied to either pars compacta or pars reticulata of the rat SN.