title: Orally administered L-ornithine reduces restraint stress-induced activation of the hypothalamic-pituitary-adrenal axis in mice.
abstract: In a previous study, we confirmed that orally administered L-ornithine can be transported into the brain of mice. In addition, orally administered L-ornithine, within a limited dose range, had an anxiolytic-like effect in the elevated plus-maze test. However, the mechanism by which orally administered L-ornithine reduced the stress response in mice is still unclear. Experiment 1 determined whether orally administered L-ornithine could reduce the stress-induced activation of hypothalamic-pituitary-adrenal axis. Mice were orally administered L-ornithine (0, 0.75, 1.5 and 3 mmol/10 ml/kg, p.o.), and restrained for 30 min from 30 min post administration. There was a significant decrease in the corticosterone levels in the group receiving 0.75 mmol of L-ornithine compared to the control group. In Experiment 2, the effect of orally administered L-ornithine (0 and 0.75 mmol/10 ml/kg, p.o.) on endogenous monoamine release was investigated using in vivo microdialysis. Only the monoamines metabolites 5-hydroxyindoleacetic acid (5-HIAA), dihydroxyphenylacetic acid (DOPAC) and homovallinic acids (HVA) were detected in the present study. Dialysate concentrations of 5-HIAA, DOPAC and HVA were not significantly changed immediately after administration of L-ornithine and restraint stress. In conclusion, changes of corticosterone concentrations by orally administered L-ornithine were not related to alterations in brain monoamine metabolisms.
authors: Laboratory of Regulation in Metabolism and Behavior, Graduate School of Bioenvironmental Sciences, Kyushu University, Fukuoka 812-8581, Japan.
authors: Koji
authors: K
authors: Kurata
authors: Mao
authors: M
authors: Nagasawa
authors: Shozo
authors: S
authors: Tomonaga
authors: Mami
authors: M
authors: Aoki
authors: Saori
authors: S
authors: Akiduki
authors: Koji
authors: K
authors: Morishita
authors: D Michael
authors: DM
authors: Denbow
authors: Mitsuhiro
authors: M
authors: Furuse
mesh_terms: D015102:3,4-Dihydroxyphenylacetic Acid / Q000032:analysis / Q000378:metabolism; D000284:Administration, Oral; D000818:Animals; D014151:Anti-Anxiety Agents / Q000008:administration & dosage; D001921:Brain / Q000378:metabolism*; D001923:Brain Chemistry / Q000187:drug effects; D002851:Chromatography, High Pressure Liquid; D003345:Corticosterone / Q000097:blood; D004797:Enzyme-Linked Immunosorbent Assay; D006719:Homovanillic Acid / Q000032:analysis / Q000378:metabolism; D006897:Hydroxyindoleacetic Acid / Q000032:analysis / Q000378:metabolism; D007030:Hypothalamo-Hypophyseal System / Q000187:drug effects* / Q000378:metabolism; D008297:Male; D051379:Mice; D008813:Mice, Inbred ICR; D017551:Microdialysis; D009952:Ornithine / Q000008:administration & dosage* / Q000378:metabolism; D010913:Pituitary-Adrenal System / Q000187:drug effects* / Q000378:metabolism; D012149:Restraint, Physical; D013315:Stress, Psychological / Q000378:metabolism*
chemical_list: D014151:Anti-Anxiety Agents; D015102:3,4-Dihydroxyphenylacetic Acid; D006897:Hydroxyindoleacetic Acid; D009952:Ornithine; D003345:Corticosterone; D006719:Homovanillic Acid