Suppression of conditioned avoidance behavior by the local application of (−)sulpiride into the ventral, but not the dorsal, striatum of the rat

Abstract

The local application of (−)sulpiride, 200 ng side −1, into the nucleus accumbens produced a suppression of conditioned avoidance behavior in male rats, 10 and 90 min after injection. The decrease in avoidance behavior was accompained by a decrease in motor activity, as evidenced by changes in the number of intertrial crosses. When injected into the dorsolateral neostriatum, or the amygdala, (−)sulpiride produced a suppression of conditioned avoidance behavior at the 90-min time interval only. Considering diffusion from the injection site, as indicated by an increase in local dopamine turnover [( DO- PAC+ HVA) DA −1], the effects obtained in the dorsolateral neostriatum, and possibly also the amygdala, 90 min after injection could be due to diffusion to the nucleus accumbens. The local application of (-) sulpiride into the posterior neostriatum, or into the prefrontal cortex, produced no statistically significant effect on conditioned avoidance behavior 10 or 90 min after injection. It is concluded that the performance of conditioned avoidance behavior in the rat is critically dependent on an intact dopaminergic neurotransmission in the nucleus accumbens or adjacent areas of the ventral striatum.