title: Enhancement of learning behaviour by a potent nitric oxide-guanylate cyclase activator YC-1.
abstract: Memory is one of the most fundamental mental processes, and various approaches have been used to understand the mechanisms underlying this process. Nitric oxide (NO), cGMP and protein kinase G (PKG) are involved in the modulation of synaptic plasticity in various brain regions. YC-1, which is a benzylindazole derivative, greatly potentiated the response of soluble guanylate cyclase to NO (up to several hundreds fold). We have previously shown that YC-1 markedly enhances long-term potentiation in hippocampal and amygdala slices via NO-cGMP-PKG-dependent pathway. We here further investigated whether YC-1 promotes learning behaviour in Morris water maze and avoidance tests. It was found that YC-1 shortened the escape latency in the task of water maze, increased and decreased the retention scores in passive and active avoidance task, respectively. Administration of YC-1 30 min after foot-shock stimulation did not significantly affect retention scores in response to passive avoidance test. Administration of scopolamine, a muscarinic antagonist, markedly impaired the memory acquisition. Pretreatment of YC-1 inhibited the scopolamine-induced learning deficit. The enhancement of learning behaviour by YC-1 was antagonized by intracerebroventricular injection of NOS inhibitor L-NAME and PKG inhibitors of KT5823 and Rp-8-Br-PET-cGMPS, indicating that NO-cGMP-PKG pathway is also involved in the learning enhancement action of YC-1. YC-1 is thus a good drug candidate for the improvement of learning and memory.
authors.affiliation: Pharmacological Institute, College of Medicine, National Taiwan University, No. 1, Sec. 1, Jen-Ai Road, Taipei, Taiwan.
authors.forename: Wei-Lin
authors.initials: WL
authors.lastname: Chien
authors.forename: Keng-Chen
authors.initials: KC
authors.lastname: Liang
authors.forename: Che-Ming
authors.initials: CM
authors.lastname: Teng
authors.forename: Sheng-Chu
authors.initials: SC
authors.lastname: Kuo
authors.forename: Fang-Yu
authors.initials: FY
authors.lastname: Lee
authors.forename: Wen-Mei
authors.initials: WM
authors.lastname: Fu
mesh_terms: D000818:Animals; D020536:Enzyme Activators / Q000494:pharmacology*; D019706:Excitatory Postsynaptic Potentials / Q000187:drug effects / Q000502:physiology; D006162:Guanylate Cyclase / Q000378:metabolism*; D007191:Indazoles / Q000494:pharmacology*; D007858:Learning / Q000187:drug effects* / Q000502:physiology; D009569:Nitric Oxide / Q000378:metabolism*; D018697:Nootropic Agents / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar; D011930:Reaction Time / Q000187:drug effects / Q000502:physiology
chemical_list: D020536:Enzyme Activators; D007191:Indazoles; D018697:Nootropic Agents; C090937:3-(5'-hydroxymethyl-2'-furyl)-1-benzylindazole; D009569:Nitric Oxide; D006162:Guanylate Cyclase