NMDA-but not AMPA-receptor antagonists augment scopolamine-induced spatial cognitive deficit of rats in a radial maze task.

The effect of NMDA and AMPA receptor antagonists on a scopolamine-induced spatial cognitive deficit was investigated in rats using an 8-arm radial maze. The NMDA antagonists, MK801 and CGS19755, robustly augmented scopolamine-induced deficits but had no effect on spatial cognition when administered alone. In contrast, augmentation of the scopolamine-induced deficits was not observed when the selective AMPA antagonist, YM90K, was administered with scopolamine. These results suggest that the NMDA but not AMPA subtypes of the ionotropic glutamate receptors play important roles in regulation of the central cholinergic function related to the spatial learning and memory processes.