title: Role of nitric oxide and cyclic GMP in the dizocilpine-induced impairment of spontaneous alternation behavior in mice.
abstract: The activation of N-methyl-D-aspartate receptors induces the synthesis of nitric oxide, which activates soluble guanylate cyclase and leads to the formation of cyclic GMP in the brain. The inhibition of nitric oxide production, as well as the blockade of N-methyl-D-aspartate receptors, has been reported to prevent the induction of hippocampal long-term potentiation and learning and memory formation in vivo, although the effects of inhibitors of nitric oxide synthase are still controversial. We investigated the putative role of nitric oxide and cyclic GMP in dizocilpine-induced memory impairment in mice. The nitric oxide synthase inhibitors, NG-nitro-L-arginine methyl ester and 7-nitro indazole, as well as dizocilpine, a non-competitive N-methyl-D-aspartate receptor antagonist, dose-dependently impaired spatial working memory in mice, assessed by their spontaneous alternation behavior in a Y-maze. The inhibitory effects of both NG-nitro-L-arginine methyl ester and dizocilpine on their behavior were completely reversed by 8-bromo-cyclic GMP. Cyclic GMP levels in the cerebellum were reduced by treatment with dizocilpine. NG-Nitro-L-arginine methyl ester and 7-nitro indazole reduced cyclic GMP levels in the cerebral cortex/hippocampus and cerebellum, and the suppressive effect of NG-nitro-L-arginine methyl ester on cyclic GMP levels in the cerebral cortex/hippocampus was reversed by co-treatment with L-arginine. Cyclic AMP levels in the brain were not affected by treatment with either dizocilpine, NG-nitro-L-arginine methyl ester, or 7-nitro indazole. Neither NG-nitro-L-arginine methyl ester nor L-arginine had any effect on monoamine and acetylcholine metabolism in the brain. These results suggest that the reduction in nitric oxide/cyclic GMP production in the brain may be responsible for dizocilpine-induced impairment of spontaneous alternation behavior in a Y-maze.
authors.affiliation: Department of Neuropsychopharmacology and Hospital Pharmacy, Nagoya University School of Medicine, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Yamada
authors.forename: M
authors.initials: M
authors.lastname: Hiramatsu
authors.forename: Y
authors.initials: Y
authors.lastname: Noda
authors.forename: T
authors.initials: T
authors.lastname: Mamiya
authors.forename: M
authors.initials: M
authors.lastname: Murai
authors.forename: T
authors.initials: T
authors.lastname: Kameyama
authors.forename: Y
authors.initials: Y
authors.lastname: Komori
authors.forename: T
authors.initials: T
authors.lastname: Nikai
authors.forename: H
authors.initials: H
authors.lastname: Sugihara
authors.forename: T
authors.initials: T
authors.lastname: Nabeshima
mesh_terms: D000818:Animals; D001522:Behavior, Animal / Q000187:drug effects*; D006152:Cyclic GMP / Q000378:metabolism*; D016291:Dizocilpine Maleate / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D008297:Male; D018782:Maze Learning / Q000187:drug effects*; D051379:Mice; D008815:Mice, Inbred Strains; D019331:NG-Nitroarginine Methyl Ester / Q000494:pharmacology; D009569:Nitric Oxide / Q000494:pharmacology*
chemical_list: D009569:Nitric Oxide; D016291:Dizocilpine Maleate; D006152:Cyclic GMP; D019331:NG-Nitroarginine Methyl Ester