Effects of memantine on latent inhibition of active avoidance in wistar rats.

Latent inhibition of active avoidance reaction was acquired by mature Wistar rats. It manifested in marked delay of habit acquisition after preexposure to the conditional stimulus in the first experimental session. Single dose of NMDA-receptor antagonist memantine (10 and 14 mg/kg) was applied 60 min before training in the second session. Failure of latent inhibition formation was registered after administration of the higher memantine dose; it manifested in accelerated attaining of the criterion (7 successive conditioned avoidance reactions) compared to training results after administration of the lower dose or physiological saline. The effects of memantine on attention were found to depend on the presence of pathology. It was hypothesized that the preparation can produce a positive effect on memory in Alzheimer-type dementia due to primary recovery of the inhibitory aspect of attention.