Detailed behavioral analysis of water maze acquisition under APV or CNQX: contribution of sensorimotor disturbances to drug-induced acquisition deficits.

N-methyl-D-aspartate (NMDA) receptor antagonists disrupt acquisition of the water maze and cause sensorimotor disturbances. In a detailed behavioral analysis in male rats, it was found that the NMDA antagonist DL-2-aminophosphonovaleric acid (APV) caused sensorimotor disturbances in behaviors required for maze performance and that these correlated with acquisition impairments in both hidden and visible platform versions of the maze. Behavioral disturbances included thigmotaxic swimming, swimming over and deflecting off the platform, abnormal swim behavior, and hyperactivity. Rats familiar with the behavioral strategies involved in the task performed normally under APV. The results are consistent with the known role of NMDA receptors in sensorimotor mechanisms and suggest that drug-induced sensorimotor disturbances contributed to poor acquisition scores in naive rats. NMDA may contribute to but does not appear to be essential for spatial learning in the water maze.