A comparison of bromopride and domperidone effects on rat conditioned avoidance and motor activity

Acute intraperitoneal administration of bromopride (BRO) and domperidone (DOMP), two dopamine D2 blockers used as antiemetics in gastroenterology, were tested in male rats for effects on motor activity and on active and inhibitory conditioned behaviour. BRO dose-dependently depressed ambulation and rearing, impairing the performance of active conditioned avoidance (CAR) even when injected prior to the retention session. It also impaired inhibitory avoidance responses (IAR). All these effects were dose-dependent. DOMP was ineffective at modifying any of the above described parameters. These results suggest that BRO exerts neuroleptic effects which are neither mediated by actions on peripheral dopamine receptors nor by increased prolactin levels. These data also suggest that DOMP is a more appropriate drug for gastroenterology.