Buspirone blocks the enhancing effect of the anxiogenic drug RS 79948-197 on consolidation of habit memory.

Previous findings indicate that post-training administration of the anxiogenic α(2)-adrenoceptor antagonist RS 79948-197 facilitates the consolidation of dorsal striatal-dependent habit memory. The present study examined the effect of concurrent administration of the anxiolytic serotonin 5-HT(1A) receptor partial agonist buspirone on anxiety-induced facilitation of habit memory. Male Long-Evans rats were trained in a response learning version of a water plus-maze task that requires animals to learn to make the same body turn response on each trial in order to reach a hidden escape platform. Immediately following training on days 1-3, rats received peripheral injections of either saline, buspirone (1.5 mg/kg, 2.0 mg/kg, or 5.0 mg/kg), RS 79948-197 (0.1 mg/kg), or RS 79948-197 and buspirone together. Post-training injections of RS 79948-197 alone significantly enhanced memory consolidation. The highest dose of buspirone (5.0 mg/kg) also enhanced response learning. However, concurrent administration of a dose of buspirone (1.5 mg/kg) that itself had no effect on acquisition blocked the memory enhancing effects of RS 79948-197. These findings suggest that the facilitation of habit memory observed following drug-induced anxiety can be prevented by co-administration of an anxiolytic agent.