Evidence for the involvement of neuronal nitric oxide synthase and soluble guanylate cyclase on cognitive functions in rats

Aims: The influence of 3-bromo-7-nitroindazole (3-Br 7-NI), a potent and selective neuronal nitric oxide synthase (nNOS) inhibitor, and [1H-[1,2,4]-oxadiazole[4,3a]-quinoxaline-1-one] (ODQ), a highly selective, irreversible inhibitor of soluble guanylate cyclase (sGC), on working and reference memory and emotional learning was investigated in rats. Main methods: The effects were assessed in the three-panel runway and step-down passive avoidance task. respectively. Key findings: 3-Br 7-NI (5, 10, and 20 mg/kg) and ODQ (5, 10, and 20 mg/kg) significantly increased the number of errors and latency of both working and reference memory performance of rats and impaired retention for the passive avoidance task. The effect of 3-Br 7-NI was reversed by L-arginine (250 mg/kg). Significance: Findings of the study supported the hypothesis that nNOS inhibition disrupts reference and working memory processes in terms of an impairment in the strategies used for solving learning tasks, and, according to these results, nNOS-sGC may be required for emotional learning and both reference and working memory. (C) 2011 Elsevier Inc. All rights reserved.Kocaeli UniversityKocaeli University [2007-2010/39]This study was supported by a grant from Kocaeli University Research Fund (Project number: 2007-2010/39) and preliminary findings of the study was presented at the 9th World Congress of Biological Psychiatry, June 28-July 2, 2009, Paris-France

Effects of a dragonfly (Anax i.) homeopathic remedy on learning, memory and cell morphology in mice

PMID = 2682800

Involvement of serotonin receptor subtypes in the antidepressant-like effect of beta receptor agonist Amibegron (SR 58611A): an experimental study

PMID = 2338052

7-NI and ODQ Disturbs Memory in the Elevated plus Maze, Morris Water Maze, and Radial Arm Maze Tests in Mice

Nitric oxide (NO) is an atypical neurotransmitter that causes changes in cognition. Nitric oxide synthase (NOS) and guanylate cyclase (GC) inhibitors have been shown to exert some effects on cognition in previous studies; however, the findings have been controversial. This study was aimed at understanding the effects of an NOS inhibitor, 7-nitroindazole (7-NI), and a guanylate cyclase inhibitor, 1 H -[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one (ODQ), on spatial memory in modified elevated plus maze (mEPM), Morris water maze (MWM), and radial arm maze (RAM) tests. Male Balb-c mice were treated via intraperitoneal injections with 7-NI (15 mg/kg), ODQ (3, 10 mg/kg), L-arginine (100 mg/kg) + 7-NI (15 mg/kg), or physiological saline. ODQ (3 mg/kg) and 7-NI (15 mg/kg) significantly increased the second-day latency in the mEPM test. 7-NI (15 mg/kg) and ODQ (10 mg/kg) significantly increased the escape latency in second, third, and fourth sessions, decreased the time spent in the escape platform's quadrant, and increased the mean distance to the platform in the probe trial of the MWM test. ODQ (3, 10 mg/kg) and 7-NI (15 mg/kg) significantly increased the number of errors, whereas only 7-NI increased the latency in the RAM test. The administration of L-arginine (100 mg/kg) prior to 7-NI inverted the effects of 7-NI, which supports the role of NO on cognition. Our study shows that the NO/cGMP/GS pathway can regulate spatial memory in mice