IMMUNOHISTOCHEMICAL ALTERATIONS IN NEUROPEPTIDE Y-POSITIVE NERVE ELEMENTS IN RAT CEREBRAL-CORTEX FOLLOWING ACUTE PHENCYCLIDINE TREATMENT

PHENCYCLIDINE (PCP) is a dissociative drug and has been known to be an antagonist of N-methyl-D-aspartate (NMDA) receptor. We examined possi ble effects of acute treatment with PCP on neuropeptide Y (NPY) immuno reactive nerve fibres and cell bodies in rat forebrain by immunocytoch emistry combined with morphometric analysis. Following the treatment, significant alterations were observed throughout the cerebral cortex, compared with controls. NPY-positive perikarya were increased in numbe r (178%) whereas NPY-positive fibres and terminals were decreased in a rea (38%). The result suggests that the cortical NPY neuronal system i s controlled, at least partly, by glutamatergic inputs via NMDA recept or-mediated mechanisms.