NPY Y1 RECEPTOR-LIKE IMMUNOREACTIVITY EXISTS IN A SUBPOPULATION OF BETA-ENDORPHIN IMMUNOREACTIVE NERVE-CELLS IN THE ARCUATE NUCLEUS - A DOUBLE IMMUNOLABELING ANALYSIS IN THE RAT

Double immunolabelling immunohistochemistry in the arcuate nucleus of the rat demonstrates that neuropeptide Y (NPY) Y1 receptor like immuno reactivity is strongly present in a subpopulation of beta-endorphin im munoreactive nerve cell bodies, while the small NPY immunoreactive ner ve cell bodies located medially lack NPY Y1 receptor like immunoreacti vity. The NPY Y1 like immunoreactive nerve cell bodies lie in an arcua te area rich in NPY immunoreactive nerve terminals forming an uniform plexus. It is postulated that NPY Y1 receptors in beta-endorphin neuro ns may mediate some actions of NPY on motivational processes and pain control as well as on hypophyseal hormone secretion, involving at the least in part a regulation of the tubero-infundibular DA neurons (C) 1 997 Elsevier Science Ireland Ltd.