Immunohistochemical localization of the neuropeptide YY1 receptor in rat central nervous system

The diverse effects of neuropeptide Y (NPY) are mediated through interactio n with G-protein coupled receptors. Pharmacological analysis suggests the Y 1 receptor mediates several of NPY's central and peripheral actions. We sou ght to determine the distribution of Y1 protein throughout the rat central nervous system by means of indirect immunofluorescence using the tyramide s ignal amplification method and a novel, amino terminally-directed Y1 antise ra. This antisera was verified as specific for Y1 by solution-phase competi tion ELISA, Western blot and in situ blocking experiments. High concentrati ons of Y1 immunoreactivity were found in the claustrum, piriform cortex (su perficial layer), arcuate hypothalamic nucleus, interpeduncular nucleus, pa ratrigeminal nucleus, and lamina II of the spinal trigeminal nucleus and en tire spinal cord. Moderate levels of Y1 immunoreactivity were found the in the main olfactory bulb, dorsomedial part of suprachiasmatic nucleus, parav entricular hypothalamic nucleus, ventral nucleus of lateral lemniscus, pont ine nuclei, mesencephalic trigeminal nucleus, external cuneate nucleus, are a postrema, and nucleus tractus solitarius. Low levels of Y1 immunostaining were distributed widely throughout layers II-III of the cerebral cortex (i .e., orbital, cingulate, frontal, parietal, insular, and temporal regions), nucleus accumbens core, amygdalohippocampal and amygdalopiriform areas, de ntate gyrus, CA1 and CA2 fields of hippocampus, principal and oral division s of the spinal trigeminal nucleus, islands of Calleja and presubiculum. Th ese findings are discussed with reference to previously reported receptor a utoradiography, immunohistochemistry and mRNA analyses to further support t he role of Y1 in NPY-mediated biology. (C) 2001 Elsevier Science B.V. All r ights reserved.