title: Central injection of L- and D-aspartate attenuates isolation-induced stress behavior in chicks possibly through different mechanisms.
abstract: Intracerebroventricular (i.c.v.) injection of L- and D-aspartate (L- and D-Asp) has been shown to have a sedative effect with and without a hypnotic effect, respectively, in neonatal chicks experiencing isolation stress. However, the mechanisms of the different stress-attenuating functions of L- and D-Asp have not yet been fully clarified. In the present study, we investigated the involvement of the N-methyl-D-aspartate (NMDA) receptor in order to reveal the receptor-mediated function of L- and D-Asp. To reveal whether L-and D-Asp act through the NMDA receptor, (+)-MK-801, which is an antagonist of NMDA receptors, was used in the current study. In experiment 1, the chicks were injected i.c.v. with either saline, (+)-MK-801, L-Asp or L-Asp plus (+)-MK-801. The sedative and hypnotic effects induced by L-Asp were blocked by co-administration with (+)-MK-801. In experiment 2, the chicks were injected i.c.v. with either saline, (+)-MK-801, D-Asp or D-Asp plus (+)-MK-801. Importantly, the sedative effects induced by D-Asp were shifted to hypnotic effects by co-administration with (+)-MK-801. Taken together, L-Asp could induce sedative and hypnotic effects for stress behaviors through the NMDA receptor, but the attenuation of stress behaviors by D-Asp might be via simultaneous involvement of other receptors besides the NMDA receptor in this process. These differences may explain the different functional mechanisms of L- and D-Asp in the central nervous system.
authors.affiliation: Laboratory of Regulation in Metabolism and Behavior, Graduate School of Bioresource and Bioenvironmental Sciences, Kyushu University, Fukuoka 812-8581, Japan.
authors.forename: Edi
authors.initials: E
authors.lastname: Erwan
authors.affiliation: Division for Arts and Science, Faculty of Arts and Science, Kyushu University, Fukuoka 819-0395, Japan.
authors.forename: Vishwajit Sur
authors.initials: VS
authors.lastname: Chowdhury
authors.affiliation: Laboratory of Regulation in Metabolism and Behavior, Graduate School of Bioresource and Bioenvironmental Sciences, Kyushu University, Fukuoka 812-8581, Japan.
authors.forename: Mao
authors.initials: M
authors.lastname: Nagasawa
authors.affiliation: Laboratory of Regulation in Metabolism and Behavior, Graduate School of Bioresource and Bioenvironmental Sciences, Kyushu University, Fukuoka 812-8581, Japan.
authors.forename: Ryosei
authors.initials: R
authors.lastname: Goda
authors.affiliation: Laboratory of Regulation in Metabolism and Behavior, Graduate School of Bioresource and Bioenvironmental Sciences, Kyushu University, Fukuoka 812-8581, Japan.
authors.forename: Tsuyoshi
authors.initials: T
authors.lastname: Otsuka
authors.affiliation: Laboratory of Regulation in Metabolism and Behavior, Graduate School of Bioresource and Bioenvironmental Sciences, Kyushu University, Fukuoka 812-8581, Japan.
authors.forename: Shinobu
authors.initials: S
authors.lastname: Yasuo
authors.affiliation: Laboratory of Regulation in Metabolism and Behavior, Graduate School of Bioresource and Bioenvironmental Sciences, 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; D001224:Aspartic Acid / Q000008:administration & dosage*; D001522:Behavior, Animal / Q000187:drug effects*; D002645:Chickens; D016291:Dizocilpine Maleate / Q000494:pharmacology; D006993:Hypnotics and Sedatives / Q000008:administration & dosage*; D007276:Injections, Intraventricular; D016194:Receptors, N-Methyl-D-Aspartate / Q000037:antagonists & inhibitors / Q000378:metabolism*; D012934:Social Isolation; D013315:Stress, Psychological / Q000188:drug therapy* / Q000378:metabolism
chemical_list: D006993:Hypnotics and Sedatives; D016194:Receptors, N-Methyl-D-Aspartate; D001224:Aspartic Acid; D016291:Dizocilpine Maleate
keywords: Chick; D-Aspartate; Intracerebroventricular; L-Aspartate; NMDA receptor