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 possible effects of acute treatment with PCP on neuropeptide Y (NPY) immunoreactive nerve fibres and cell bodies in rat forebrain by immunocytochemistry combined with morphometric analysis. Following the treatment, significant alterations were observed throughout the cerebral cortex, compared with controls. NPY-positive perikarya were increased in number (178%) whereas NPY-positive fibres and terminals were decreased in area (38%). The result suggests that the cortical NPY neuronal system is controlled, at least partly, by glutamatergic inputs via NMDA receptor-mediated mechanisms.