DORSAL HIPPOCAMPAL MUSCARINIC ACETYLCHOLINE AND NMDA RECEPTORS DISRUPT WATER MAZE NAVIGATION

THE present study investigated the effects of bilateral dorsal hippoca mpal infusions with muscarinic acetylcholine (scopolamine; 3 and 10 mu g per hemisphere) and N-methyl-D-aspartate (NMDA) (CPP; 0.01 and 0.03 mu g per hemisphere) antagonists on acquisition (drug delivered befor e daily training), consolidation (drug delivered after daily training) and retrieval (drug delivered only before spatial bias test) performa nce in a water maze (WM) spatial navigation test. Scopolamine 10 mu g disrupted acquisition, but had no effect on consolidation or retrieval . CPP 0.03 mu g disrupted acquisition and retrieval behaviour. A combi nation of subthreshold doses of CPP (0.01 mu g) and scopolamine (3 mu g) disrupted acquisition performance. The treatments did not disrupt n avigation to a clearly visible escape platform. The present data indic ate that dorsal hippocampal NMDA and muscarinic acetylcholine receptor s are important for spatial navigation behaviour.