title: Abolition of the expression but not the acquisition of latent inhibition by chronic amphetamine in rats.
abstract: The animal amphetamine model of schizophrenia has been based primarily on stereotyped behavior. The present study sought to demonstrate an amphetamine-induced deficit in attentional processes. To this end, the effects of acute and chronic (14 days) 1.5 mg/kg dl-amphetamine administration on the ability of rats to ignore irrelevant stimuli were examined using the paradigm of latent inhibition (LI) in a conditioned emotional response (CER) procedure. The procedure consisted of three stages: pre-exposure, in which the to-be-conditioned stimulus, tone, was presented without being followed by reinforcement; acquisition, in which the pre-exposed tone was paired with shock; and test, in which LI was indexed by animals' suppression of licking during tone presentation. Experiment 1 showed that chronic but not acute treatment abolished LI. Experiment 2 showed that animals receiving chronic amphetamine pretreatment but pre-exposed and conditioned without the drug, exhibited normal LI. In Experiment 3, animals which received chronic amphetamine pretreatment and were pre-exposed under the drug but conditioned without it, also showed normal LI. The implications of these results for the animal amphetamine model of schizophrenia are discussed.
mesh_terms: D000661:Amphetamine / Q000494:pharmacology*; D000704:Analysis of Variance; D000818:Animals; D001288:Attention / Q000187:drug effects*; D003213:Conditioning, Psychological / Q000187:drug effects*; D004195:Disease Models, Animal; D004644:Emotions / Q000187:drug effects; D006801:Humans; D007266:Inhibition, Psychological; D008297:Male; D051381:Rats; D012559:Schizophrenia / Q000139:chemically induced
chemical_list: D000661:Amphetamine