title: L-Ornithine is a potential acute satiety signal in the brain of neonatal chicks.
abstract: Recently, we observed that neonatal chicks exhibit feeding behavior characterized by frequent food intake and short resting intervals, with changes detected in the brain amino acid and monoamine concentrations. In this study, we aimed to clarify further the relationship between the appetite of neonatal chicks and brain amino acid metabolism. In Experiment 1, changes were investigated in free amino acids in the brain under conditions of regulated appetite induced by fasting and subsequent short-term re-feeding. Chicks (5 days old) were distributed into four treatment groups--namely, fasting for 3h, and fasting for 3h followed by re-feeding for 10, 20 or 30 min. Brain samples were collected after treatment to analyze free amino acid concentrations. Amino adipic acid and proline in all brain parts as well as arginine and ornithine in all brain parts--except mesencephalic arginine and cerebellar ornithine--were increased in a time-dependent manner following re-feeding. In Experiment 2, we further examined the effect of exogenous administration of some amino acids altered in association with feeding behavior in Experiment 1. We chose L-arginine and its functional metabolite, L-ornithine, to analyze their effects on food intake in chicks. Intracerebroventricular injection (2 μmol) of L-ornithine, but not L-arginine, significantly inhibited food intake in neonatal chicks. In Experiment 3, we found that central injection of L-ornithine (2, 4, and 6 μmol) dose-dependently suppressed food intake in chicks. These results suggested that L-ornithine may have an important role in the control of food intake as an acute satiety signal in the neonatal chick brain.
authors.affiliation: Laboratory of Regulation in Metabolism and Behavior, Graduate School of Bioresource and Bioenvironmental Science, Kyushu University, Fukuoka 812-8581, Japan.
authors.forename: Phuong V
authors.initials: PV
authors.lastname: Tran
authors.affiliation: Division for Experimental Natural Science, Faculty of Arts and Science, Kyushu University, Fukuoka 819-0395, Japan.
authors.forename: Vishwajit S
authors.initials: VS
authors.lastname: Chowdhury
authors.affiliation: Laboratory of Regulation in Metabolism and Behavior, Graduate School of Bioresource and Bioenvironmental Science, Kyushu University, Fukuoka 812-8581, Japan.
authors.forename: Phong H
authors.initials: PH
authors.lastname: Do
authors.affiliation: Laboratory of Regulation in Metabolism and Behavior, Graduate School of Bioresource and Bioenvironmental Science, Kyushu University, Fukuoka 812-8581, Japan.
authors.forename: Mohammad A
authors.initials: MA
authors.lastname: Bahry
authors.affiliation: Laboratory of Regulation in Metabolism and Behavior, Graduate School of Bioresource and Bioenvironmental Science, Kyushu University, Fukuoka 812-8581, Japan.
authors.forename: Hui
authors.initials: H
authors.lastname: Yang
authors.affiliation: Laboratory of Regulation in Metabolism and Behavior, Graduate School of Bioresource and Bioenvironmental Science, Kyushu University, Fukuoka 812-8581, Japan. Electronic address: furuse@brs.kyushu-u.ac.jp.
authors.forename: Mitsuhiro
authors.initials: M
authors.lastname: Furuse
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D001120:Arginine / Q000008:administration & dosage / Q000378:metabolism; D001921:Brain / Q000187:drug effects / Q000378:metabolism*; D002491:Central Nervous System Agents / Q000008:administration & dosage; D002645:Chickens; D002851:Chromatography, High Pressure Liquid; D004305:Dose-Response Relationship, Drug; D004435:Eating / Q000187:drug effects / Q000502:physiology; D008297:Male; D009952:Ornithine / Q000008:administration & dosage / Q000378:metabolism*; D011897:Random Allocation; D012527:Satiation / Q000187:drug effects / Q000502:physiology*
chemical_list: D002491:Central Nervous System Agents; D001120:Arginine; D009952:Ornithine
keywords: Brain; Food intake; Free amino acids; Neonatal chick; l-Ornithine