title: Role of oleoylethanolamide as a feeding regulator in goldfish.
abstract: Oleoylethanolamide (OEA) is a bioactive lipid mediator, produced in the intestine and other tissues, which is involved in energy balance regulation in mammals, modulating feeding and lipid metabolism. The purpose of the present study was to investigate the presence and possible role of OEA in feeding regulation in goldfish (Carassius auratus). We assessed whether goldfish peripheral tissues and brain contain OEA and their regulation by nutritional status. OEA was detected in all studied tissues (liver, intestinal bulb, proximal intestine, muscle, hypothalamus, telencephalon and brainstem). Food deprivation (48 h) reduced intestinal OEA levels and levels increased upon re-feeding, suggesting that this compound may be involved in the short-term regulation of food intake in goldfish, as a satiety factor. Next, the effects of acute intraperitoneal administration of OEA on feeding, swimming and plasma levels of glucose and triglycerides were analysed. Food intake, swimming activity and circulating triglyceride levels were reduced by OEA 2 h post-injection. Finally, the possible interplay among OEA and other feeding regulators (leptin, cholecystokinin, ghrelin, neuropeptide Y, orexin and monoamines) was investigated. OEA actions on energy homeostasis in goldfish could be mediated, at least in part, through interactions with ghrelin and the serotonergic system, as OEA treatment reduced ghrelin expression in the intestinal bulb, and increased serotonergic activity in the telencephalon. In summary, our results indicate for the first time in fish that OEA could be involved in the regulation of feeding, swimming and lipid metabolism, suggesting a high conservation of OEA actions in energy balance throughout vertebrate evolution.
authors.affiliation: Departamento de Fisiología (Fisiología Animal II), Facultad de Biología, Universidad Complutense de Madrid, 28040 Madrid, Spain.
authors.forename: Ana B
authors.initials: AB
authors.lastname: Tinoco
authors.affiliation: Department of Drug Discovery and Development, Istituto Italiano di Tecnologia, 16163 Genoa, Italy.
authors.forename: Andrea
authors.initials: A
authors.lastname: Armirotti
authors.affiliation: Departamento de Fisiología (Fisiología Animal II), Facultad de Biología, Universidad Complutense de Madrid, 28040 Madrid, Spain.
authors.forename: Esther
authors.initials: E
authors.lastname: Isorna
authors.affiliation: Departamento de Fisiología (Fisiología Animal II), Facultad de Biología, Universidad Complutense de Madrid, 28040 Madrid, Spain.
authors.forename: María J
authors.initials: MJ
authors.lastname: Delgado
authors.affiliation: Department of Drug Discovery and Development, Istituto Italiano di Tecnologia, 16163 Genoa, Italy.
authors.forename: Daniele
authors.initials: D
authors.lastname: Piomelli
authors.affiliation: Departamento de Fisiología (Fisiología Animal II), Facultad de Biología, Universidad Complutense de Madrid, 28040 Madrid, Spain ndepedro@ucm.es.
authors.forename: Nuria
authors.initials: N
authors.lastname: de Pedro
mesh_terms: D000818:Animals; D001786:Blood Glucose; D004435:Eating / Q000187:drug effects*; D063388:Endocannabinoids / Q000032:analysis / Q000378:metabolism* / Q000494:pharmacology*; D005508:Food Deprivation / Q000502:physiology; D006054:Goldfish; D007274:Injections, Intraperitoneal; D050356:Lipid Metabolism / Q000502:physiology*; D009479:Neuropeptides / Q000378:metabolism*; D009829:Oleic Acids / Q000032:analysis / Q000378:metabolism* / Q000494:pharmacology*; D036361:Peptide Hormones / Q000378:metabolism*; D013550:Swimming / Q000502:physiology; D014280:Triglycerides / Q000097:blood
chemical_list: D001786:Blood Glucose; D063388:Endocannabinoids; D009479:Neuropeptides; D009829:Oleic Acids; D036361:Peptide Hormones; D014280:Triglycerides; C488250:oleoylethanolamide
keywords: Carassius auratus; Fatty acid ethanolamide; Food intake; Locomotor activity; Monoamines; Triglycerides