title: Brain and intestinal expression of galanin-like peptide (GALP), galanin receptor R1 and galanin receptor R2, and GALP regulation of food intake in goldfish (Carassius auratus).
abstract: Galanin-like peptide (GALP) is a 60 amino acid neuropeptide originally discovered from porcine hypothalamus, and is involved in the regulation of food intake in mammals. Since its discovery, GALP and its receptors (GALR1 and GALR2) have been characterized in mammals, but no publications are available on GALP in fish and other non-mammals. The present study aimed to characterize brain and intestinal GALP and its receptors using immunohistochemistry in a teleost, the goldfish (Carassius auratus), and to study its effects on feeding behavior. Immunostaining of brain sections shows the presence of GALP- and GALR1- and GALR2-like immunoreactive cells in different encephalic areas, including the telencephalon, some hypothalamic nuclei, the optic tectum, the torus longitudinalis and the cerebellum. Signal for GALP was also observed in the fasciculus retroflexus. In the gut, GALP-and GALR1 and GALR2 immunoreactive cells were detected in the mucosa. Results from the feeding study demonstrate that intracerebroventricular administration of GALP (1ng/g bodyweight) increases goldfish food intake at 1h post-injection. These observations form the first report on the presence of GALP in the fish brain and gut, and also on its modulatory role on fish feeding behavior. GALP, as in mammals, appears to be a functional neuropeptide in goldfish.
authors.affiliation: Department of Biology, York University, Toronto, Canada. Electronic address: elsietm@gmail.com.
authors.forename: Elsie Tachie
authors.initials: ET
authors.lastname: Mensah
authors.affiliation: Laboratory of Integrative Neuroendocrinology, Department of Veterinary Biomedical Sciences, Western College of Veterinary Medicine, University of Saskatchewan, 52 Campus Drive, S7N 5B4 Saskatoon, Saskatchewan, Canada; Departamento de Fisiología (Fisiología Animal II), Facultad de Biología, Universidad Complutense de Madrid, José Antonio Nováis 12, 28040 Madrid, Spain. Electronic address: ayelenmelisablanco@ucm.es.
authors.forename: Ayelén Melisa
authors.initials: AM
authors.lastname: Blanco
authors.affiliation: Department of Biology, York University, Toronto, Canada. Electronic address: adonini@yorku.ca.
authors.forename: Andrew
authors.initials: A
authors.lastname: Donini
authors.affiliation: Laboratory of Integrative Neuroendocrinology, Department of Veterinary Biomedical Sciences, Western College of Veterinary Medicine, University of Saskatchewan, 52 Campus Drive, S7N 5B4 Saskatoon, Saskatchewan, Canada. Electronic address: suraj.unniappan@usask.ca.
authors.forename: Suraj
authors.initials: S
authors.lastname: Unniappan
mesh_terms: D000821:Animal Feed; D000818:Animals; D001835:Body Weight / Q000502:physiology; D001921:Brain / Q000378:metabolism; D004435:Eating / Q000502:physiology*; D005260:Female; D019004:Galanin / Q000378:metabolism*; D044089:Galanin-Like Peptide / Q000378:metabolism*; D006054:Goldfish; D007276:Injections, Intraventricular / Q000379:methods; D008297:Male; D044091:Receptor, Galanin, Type 1 / Q000378:metabolism*; D044092:Receptor, Galanin, Type 2 / Q000378:metabolism*
chemical_list: D044089:Galanin-Like Peptide; D044091:Receptor, Galanin, Type 1; D044092:Receptor, Galanin, Type 2; D019004:Galanin
keywords: Brain; Feeding; Fish; Galanin-like peptide; Gut; Immunohistochemistry