ONDANSETRON FAILS TO ATTENUATE A SCOPOLAMINE-INDUCED DEFICIT IN A STONE MAZE TASK

THE 5-HT, receptor antagonist ondansetron has previously been reported to improve cognition in the mouse, rat and marmoset in a variety of behavioural paradigms. The present study used the Stone maze to test the effect of ondansetron on the deficit caused by scopolamine in the performance of a highly complex spatial memory task in the rat. Ondansetron administered over a large dose range (1.0 ng kg(-1)-1.0 mu g kg(-1), i.p., b.d.) for a period of 10-15 days failed to attenuate the scopolamine deficit. Indeed at one dose level ondansetron (100 ng kg(-1), i.p., b.d.) administered in combination with scopolamine (0.5 mg kg(-1), i.p.) significantly potentiated the deficit, compared with the performance of rats receiving scopolamine alone.