Loss of discriminative avoidance behavior by local application of kynurenic acid into the nucleus accumbens of the rat

Abstract

Male Sprague-Dawley rats, trained to perform a visual discrimination, were administered kynurenic acid, an antagonist of excitatory amino acid receptors, 4.7 micrograms bilaterally into the nucleus accumbens. The performance of the visual discrimination was impaired 15, but not 360, min after administration. In addition, motor activity in the test apparatus was markedly increased by the treatment, whereas no effects were noted when the animals were observed in an open field. The abnormal behavior produced by kynurenic acid has previously been observed after administration of high doses of compounds like d-amphetamine and L-DOPA, and generally discriminative behavior has been shown to be highly dependent on normal impulse mediated release of dopamine in brain. The present results show that this behavior also is dependent on an intact excitatory amino acid neurotransmission.