title: Neuropeptide-Y and ACTH-immunoreactive innervation of corticotropin releasing factor (CRF)-synthesizing neurons in the hypothalamus of the rat. An immunocytochemical analysis at the light and electron microscopic levels.
abstract: Corticotropin releasing factor (CRF), synthesized in neurons of the hypothalamic paraventricular nucleus (PVN), is one of the main regulators of the pituitary-adrenal cortex endocrine axis. In order to elucidate the possible involvement of the central neuropeptide-Y (NPY)- and adrenocorticotroph hormone (ACTH)-immunoreactive (IR) systems in the innervation of hypophysiotrophic CRF-synthesizing neurons, immunocytochemical double labelling studies were conducted in the hypothalamus of the rat to localize CRF-synthesizing neurons, as well as neuronal fibers exhibiting NPY and ACTH-immunoreactivity, respectively. The parvocellular subnuclei of the PVN received an intense NPY- and ACTH-IR innervation. At the light microscopic level, these peptidergic axons were associated with the dendrites and perikarya of CRF-IR neurons. Ultrastructural analysis revealed that NPY- and ACTH-IR axons established synaptic specializations with parvocellular neurons expressing CRF-immunoreactivity. These findings indicate that both neuropeptide-Y and adrenocorticotroph hormone containing neuronal systems of the brain are capable of influencing adrenal function via synaptic interactions with hypophysiotrophic CRF-synthesizing neurons. The data also support the concept that NPY and ACTH might be utilized as neuromodulators within the PVN.
authors.affiliation: Department of Anatomy, University of Missouri-Columbia 65212.
authors.forename: Z
authors.initials: Z
authors.lastname: Liposits
authors.forename: L
authors.initials: L
authors.lastname: Sievers
authors.forename: W K
authors.initials: WK
authors.lastname: Paull
mesh_terms: D000324:Adrenocorticotropic Hormone / Q000378:metabolism*; D000344:Afferent Pathways / Q000378:metabolism; D000818:Animals; D003346:Corticotropin-Releasing Hormone / Q000096:biosynthesis*; D007150:Immunohistochemistry; D008297:Male; D008854:Microscopy, Electron; D009474:Neurons / Q000378:metabolism; D009478:Neuropeptide Y / Q000378:metabolism*; D010286:Paraventricular Hypothalamic Nucleus / Q000378:metabolism* / Q000648:ultrastructure; D051381:Rats; D011919:Rats, Inbred Strains
chemical_list: D009478:Neuropeptide Y; D000324:Adrenocorticotropic Hormone; D003346:Corticotropin-Releasing Hormone