Interaction between striatal excitatory amino acid and gamma-aminobutyric acid (GABA) receptors in the turning behaviour of rats.

N-Methyl-D-aspartate (NMDA, 500 ng/0.5 microliters), alpha-amino-3-hydroxy-5-methyl-4-isoxasole-propionic acid (AMPA, 1000 ng/0.5 microliters), or kainic acid (50 ng/0.5 microliters) injected into intermediate and caudal parts of the caudate-putamen induced contralateral head turns and rotations. Picrotoxin (250 ng/0.5 microliters) injected into the same striatal region 30 min before NMDA, AMPA, or kainic acid strongly increased the contralateral turning induced by each of those compounds. The present results suggest that blockade of gamma-aminobutyric acid (GABA)A receptor complex by picrotoxin rendered striatal neurons more sensitive to the action of glutamate on NMDA and non-NMDA receptors.