title: Hypothalamic neuropeptide Y (NPY) gene expression is not affected by central serotonin in the rainbow trout (Oncorhynchus mykiss).
abstract: Mammalian studies have shown a link between serotonin (5-HT) and neuropeptide Y (NPY) in the acute regulation of feeding and energy homeostasis. Taking into account that the actions of 5-HT and NPY on food intake in fish are similar to those observed in mammals, the objective of this study was to characterize a possible short-term interaction between hypothalamic 5-HT and NPY, by examining whether 5-HT regulates NPY gene expression, to help clarify the mechanism underlying the observed anorexigenic action of central 5-HT in the rainbow trout. We used qRT-PCR to determine the levels of NPY mRNA in the hypothalamus-preoptic area (HPA) of rainbow trout after intraperitoneal (i.p.) injection of a single dose of dexfenfluramine (dFF, 3mgkg(-1); 24h-fasted and fed fish) or intracerebroventricular (i.c.v.) administration of 5-HT (100μgkg(-1); 24h-fasted fish). Significant suppression of food intake was observed after administration of 5-HT and dFF. No significant changes in NPY gene expression were obtained 150min after administration of 5-HT or dFF. However, administration of the 5HT1B receptor agonist anpirtoline did not have any significant effect on food intake in rainbow trout. The results suggest that in fish, unlike in mammals, neither the NPY neurons of the HPA nor the 5-HT1B receptor subtype participate in the neural circuitry involved in the inhibition of food intake induced by central serotoninergic activation.
authors.affiliation: Laboratorio de Fisiología Animal (Instituto de Acuicultura), Facultad de Biología, Universidad de Santiago de Compostela, 15782 Santiago de Compostela, Spain.
authors.forename: María J
authors.initials: MJ
authors.lastname: Mancebo
authors.forename: Francisco C
authors.initials: FC
authors.lastname: Ceballos
authors.forename: Jorge
authors.initials: J
authors.lastname: Pérez-Maceira
authors.forename: Manuel
authors.initials: M
authors.lastname: Aldegunde
mesh_terms: D000818:Animals; D020372:Dexfenfluramine / Q000008:administration & dosage / Q000494:pharmacology; D005247:Feeding Behavior / Q000187:drug effects; D005786:Gene Expression Regulation / Q000187:drug effects; D007031:Hypothalamus / Q000187:drug effects / Q000378:metabolism*; D007274:Injections, Intraperitoneal; D009478:Neuropeptide Y / Q000235:genetics* / Q000378:metabolism; D017686:Oncorhynchus mykiss / Q000235:genetics*; D010880:Piperidines / Q000008:administration & dosage / Q000494:pharmacology; D011725:Pyridines / Q000008:administration & dosage / Q000494:pharmacology; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D012701:Serotonin / Q000008:administration & dosage / Q000494:pharmacology*
chemical_list: D009478:Neuropeptide Y; D010880:Piperidines; D011725:Pyridines; D012333:RNA, Messenger; C075631:anpirtoline; D012701:Serotonin; D020372:Dexfenfluramine
keywords: Food intake; Hypothalamus; NPY mRNA; Serotonin