3-Bromo-7-nitroindazole is a specific neuronal nitric oxide synthase (nNOS) inhibitor. It affects the intercellular messenger NO synthesis throughout the brain and body.
Male rats received either 3-Bromo-7-nitroindazole (20mg/kg/day) or saline via intraperitoneal injection for 5days. Daily administration of the specific neuronal nitric oxide synthase (nNOS) inhibitor, 3-Bromo-7-nitroindazole impaired the acquisition of the Morris water maze (MWM) paradigm task. 3-Bromo-7-nitroindazole also impaired the probe trial. The MWM training was associated with a significant increase in the brain-derived neurotrophic factor (BDNF) mRNA expression in the hippocampus. BDNF mRNA expression in the hippocampus did not change after 3-Bromo-7-nitroindazole treatment. L-arginine significantly reversed behavioural parameters, and the effect of 3-Bromo-7-nitroindazole was found to be NO-dependent. There were no differences in locomotor activity and blood pressure in 3-Bromo-7-nitroindazole treated rats[1].