title: Corticotropin-releasing hormone mediates alpha-melanocyte-stimulating hormone-induced anorexigenic action in goldfish.
abstract: alpha-Melanocyte-stimulating hormone (alpha-MSH) and corticotropin-releasing hormone (CRH) both suppress food intake, and the alpha-MSH- or CRH-signaling pathway has possible potency to mediate anorexigenic actions induced by most other neuropeptides in goldfish. Therefore, using specific receptor antagonists, we examined whether the anorexigenic actions of alpha-MSH and CRH mutually interact. The inhibitory effect of ICV injection of the alpha-MSH agonist, melanotan II (MT II), on food intake was abolished by treatment with a CRH 1/2 receptor antagonist, alpha-helical CRH((9-41)), whereas the anorexigenic action of ICV-injected CRH was not affected by treatment with a melanocortin 4 receptor antagonist, HS024. This led us to investigate whether alpha-MSH-containing neurons in the goldfish brain have direct inputs to CRH-containing neurons, using confocal laser scanning microscopy. alpha-MSH- and CRH-like immunoreactivities were distributed throughout the brain, especially in the diencephalon. alpha-MSH-containing nerve fibers or endings lay in close apposition to CRH-containing neurons in a region of the hypothalamus, the nucleus posterioris periventricularis (NPPv). These results indicate that, in goldfish, alpha-MSH-induced anorexigenic action is mediated by the CRH-signaling pathway, and that CRH plays a crucial role in the regulation of feeding behavior as an integrated anorexigenic neuropeptide in this species.
authors.affiliation: Laboratory of Regulatory Biology, Graduate School of Science and Engineering, University of Toyama, 3190-Gofuku, Toyama 930-8555, Japan. kmatsuda@sci.u-toyama.ac.jp
authors.forename: Kouhei
authors.initials: K
authors.lastname: Matsuda
authors.forename: Kenji
authors.initials: K
authors.lastname: Kojima
authors.forename: Sei-Ichi
authors.initials: S
authors.lastname: Shimakura
authors.forename: Kohei
authors.initials: K
authors.lastname: Wada
authors.forename: Keisuke
authors.initials: K
authors.lastname: Maruyama
authors.forename: Minoru
authors.initials: M
authors.lastname: Uchiyama
authors.forename: Sakae
authors.initials: S
authors.lastname: Kikuyama
authors.forename: Seiji
authors.initials: S
authors.lastname: Shioda
mesh_terms: D000818:Animals; D003346:Corticotropin-Releasing Hormone / Q000494:pharmacology*; D004435:Eating / Q000187:drug effects*; D005260:Female; D005455:Fluorescent Antibody Technique; D006054:Goldfish; D007031:Hypothalamus / Q000737:chemistry; D007276:Injections, Intraventricular; D008297:Male; D009074:Melanocyte-Stimulating Hormones / Q000494:pharmacology*; D010446:Peptide Fragments / Q000494:pharmacology*; D010456:Peptides, Cyclic / Q000494:pharmacology; D000521:alpha-MSH / Q000031:analogs & derivatives / Q000494:pharmacology
chemical_list: C116098:HS 024; D010446:Peptide Fragments; D010456:Peptides, Cyclic; D000521:alpha-MSH; C027756:MSH, 4-Nle-7-Phe-alpha-; D009074:Melanocyte-Stimulating Hormones; D003346:Corticotropin-Releasing Hormone; C045089:corticotropin releasing hormone (9-41)