PRIOR NONSPATIAL PRETRAINING ELIMINATES SENSORIMOTOR DISTURBANCES ANDIMPAIRMENTS IN WATER MAZE-LEARNING CAUSED BY DIAZEPAM

Diazepam has been reported to impair spatial learning in the water maz e. This experiment reexamined this topic using control groups that had first been non-spatially pretrained to familiarize them with the gene ral behavioral strategies required in the water maze task. Naive rats given diazepam (0.5, 3.0, 6.0 mg/kg, IF) displayed dose-related maze a cquisition impairments and sensorimotor disturbances (swimming in the periphery of the pool, deflecting off or swimming over the hidden plat form, jumping off the platform when placed there after a trial, ataxia on a narrow wooden beam). The sensorimotor disturbances interfered wi th the acquisition of information about the spatial location of the pl atform, occurred in the absence of impairments in a subsequent visible platform task or swim speed, and correlated strongly with measures of acquisition. In contrast, the non-spatially pretrained groups did not exhibit sensorimotor disturbances in the water maze and acquired the maze task as rapidly under diazepam as control rats. The non-spatially pretrained groups continued to display diazepam-induced sensorimotor disturbances (ataxia) in a novel beam walking task. CGS8216 (10.0 or 2 0.0 mg/kg), a benzodiazepine receptor antagonist, attenuated the effec t of 3.0 or 6.0 mg/kg diazepam in naive rats, suggesting that the effe cts of diazepam were mediated by benzodiazepine receptors. Occupancy o f benzodiazepine receptors by diazepam does not prevent robust spatial learning in the water maze.