Demonstrating the dose- and time-related effects of 7-nitroindazole on picrotoxin-induced convulsions, memory formation, brain nitric oxide synthase activity, and nitric oxide concentration in rats.

In this study, the dose (50, 100, 150, and 200 mg/kg)- and time (30 and 60 min)- related effects of 7-nitroindazole (7-NI), a neuronal specific inhibitor of nitric oxide synthase (NOS) were tested on picrotoxin (5 mg/kg)-induced convulsions and memory formation in rats. The changes produced by these doses of 7-NI were determined on NOS activity and nitric oxide (NO) concentration in the brain. The effects of 7-NI were tested in animals pretreated (30 min) with L-arginine (500 and 1000 mg/kg).

Evidence for an involvement of the ammonia-decreasing action of L-arginine in suppressing picrotoxin-induced convulsions in rats and its additive action with diazepam.

The effects of pre- (30 min before challenge) and post-treatment (5 min after challenge) of L-arginine (840 mg kg(-1)) were tested on picrotoxin-induced increase in ammonia concentrations in brain regions (cerebral cortex, brain stem and cerebellum) and the accompanying convulsive responses in adult male rats. The effect of pre- and post-treatment of L-arginine was tested on the action of diazepam against picrotoxin-induced convulsions. Picrotoxin-induced increase in ammonia concentrations in the brain regions was reverted partially by L-arginine pre-treatment.