Opiates and classical conditioning: selective abolition of conditioned responses by activation of opiate receptors within the central nervous system.

Abstract

Opiates produce selective abolition of aversively motivated classically conditioned responses in the rabbit. These effects are mediated by specific activation of opiate receptors within the CNS, in that this central activation is both necessary and sufficient to produce opiate-induced abolition of conditioned responding. Selective activation through opiate-.mu.-receptor interactions within the periaqueductal gray/periventricular region of the 4th ventricle may be critical in mediating this abolition.