Effects of striatal or accumbens lesions on the amphetamine-induced abolition of latent inhibition.
In this study, we tested the effects of nucleus accumbens or corpus striatum lesions on the abolition of latent inhibition induced by d-amphetamine. In the latent inhibition paradigm, animals learn to ignore a repeatedly presented nonreinforced stimulus. In this paradigm, the repeated nonreinforced preexposure to a stimulus retards subsequent conditioning to that stimulus. Pharmacological manipulations that enhance the dopaminergic function (e.g., d-amphetamine) abolish this ability to ignore an irrelevant stimulus. Previous studies have revealed a major role of the nucleus accumbens in the d-amphetamine-induced abolition of latent inhibition because intraacumbens injections of the drug mimic its systemic effects. The results of this study, however, revealed a significant increase in the disruption of latent inhibition by d-amphetamine between corpus striatum-lesioned and sham-operated rats, but a marginal difference between nucleus accumbens lesioned and sham-operated rats, which had been preexposed to the stimulus. These findings indicate that the corpus striatum plays also a major role in the disruption of latent inhibition by d-amphetamine. It seems, therefore, that the nucleus accumbens and corpus striatum may represent a functionally common system regarding the expression of latent inhibition, although different experimental manipulation can favor the one structure over the other, reflecting probably their complex function.
Konstandi
M
M
Department of Pharmacology, Medical School, University of Ioannina, Greece.
Kafetzopoulos
E
E
D000818:Animals; D003216:Conditioning, Operant / Q000187:drug effects*; D003342:Corpus Striatum / Q000033:anatomy & histology / Q000187:drug effects / Q000502:physiology*; D003913:Dextroamphetamine / Q000494:pharmacology*; D007051:Ibotenic Acid / Q000008:administration & dosage / Q000494:pharmacology; D007267:Injections; D008297:Male; D009714:Nucleus Accumbens / Q000033:anatomy & histology / Q000187:drug effects / Q000502:physiology*; D051381:Rats; D017208:Rats, Wistar
D007051:Ibotenic Acid; D003913:Dextroamphetamine