WAY100635 AND LATENT INHIBITION IN THE RAT - SELECTIVE EFFECTS AT PREEXPOSURE

The influence of the selective, silent 5HT1a antagonist WAY100635 (Wye th Research Ltd) on the latent inhibition effect was examined in a wit hin-subject, on-baseline conditioned suppression procedure in rats. WA Y100635 was found to enhance the latent inhibition effect, producing a retardation in the acquisition of conditioned suppression following a level of stimulus preexposure known to be insufficient to produce a l atent inhibition effect in control animals. This influence of the drug was restricted to its actions during the preexposure phase of the exp eriment, and the drug also abolished the unconditioned suppression of lever pressing that occurs on the first presentation of a novel audito ry stimulus. These findings are discussed in terms of the possible inf luence of serotonergic manipulations on contextual processing, and als o have important implications for current animal models of schizophren ia which stress the role of dopaminergic mechanisms in latent inhibiti on. (C) 1997 Elsevier Science B.V.