title: Orexin A enhances food intake in bullfrog larvae.
abstract: Orexin is a potent orexigenic peptide implicated in appetite regulation in rodents. However, except for teleost fish, the involvement of orexin in the regulation of feeding in non-mammalian vertebrates has not been well studied. Anuran amphibian larvae feed and grow during the pre- and prometamorphic stages. Therefore, orexigenic factors seem to play important roles in growing larvae. Indeed, our recent studies have demonstrated that neuropeptide Y and ghrelin exert orexigenic actions in bullfrog larvae during the prometamorphic stages. In this study, we examined the effect of intracerebroventricular (ICV) administration of synthetic orexin A on food intake in bullfrog larvae at the prometamorphic stages. Food intake was significantly increased by ICV administration of orexin A (at 6 pmol/g BW) during a 15-min observation period. The orexigenic action of orexin A at 6 pmol/g BW was blocked by treatment with an orexin receptor antagonist, SB334867, at 60 pmol/g BW. These results indicate that orexin A acts as an orexigenic factor in bullfrog larvae.
authors: Laboratory of Regulatory Biology, Graduate School of Science and Engineering, University of Toyama, 3190-Gofuku, Toyama, Toyama 930-8555, Japan.
authors: Shunsuke
authors: S
authors: Shimizu
authors: Laboratory of Regulatory Biology, Graduate School of Science and Engineering, University of Toyama, 3190-Gofuku, Toyama, Toyama 930-8555, Japan.
authors: Tomoya
authors: T
authors: Nakamachi
authors: Laboratory of Regulatory Biology, Graduate School of Science and Engineering, University of Toyama, 3190-Gofuku, Toyama, Toyama 930-8555, Japan.
authors: Norifumi
authors: N
authors: Konno
authors: Laboratory of Regulatory Biology, Graduate School of Science and Engineering, University of Toyama, 3190-Gofuku, Toyama, Toyama 930-8555, Japan; Laboratory of Regulatory Biology, Graduate School of Innovative Life Science, University of Toyama, 3190-Gofuku, Toyama, Toyama 930-8555, Japan. Electronic address: kmatsuda@sci.u-toyama.ac.jp.
authors: Kouhei
authors: K
authors: Matsuda
mesh_terms: D000818:Animals; D004305:Dose-Response Relationship, Drug; D004435:Eating / Q000187:drug effects*; D007276:Injections, Intraventricular; D047908:Intracellular Signaling Peptides and Proteins / Q000008:administration & dosage / Q000737:chemistry / Q000494:pharmacology*; D007814:Larva / Q000187:drug effects; D009479:Neuropeptides / Q000008:administration & dosage / Q000737:chemistry / Q000494:pharmacology*; D000068797:Orexins; D011892:Rana catesbeiana
chemical_list: D047908:Intracellular Signaling Peptides and Proteins; D009479:Neuropeptides; D000068797:Orexins
keywords: Bullfrog; Food intake; Orexigenic action; Orexin A; Prometamorphic larvae