Preventive effect of N(G)-nitro-L-arginine against L-cysteine-induced seizures in mice.

The effect of N(G)-nitro-L-arginine (NNA), an inhibitor of nitric oxide (NO) synthase on L-cysteine- induced neurotoxicity was investigated in mice. When L-cysteine (1, 2.5, 5 or 10 micromol/brain) was injected intracerebroventricular (i.c.v.) in mice, severe tonic seizures were observed for over 20 s in the treated mice in a dose-dependent manner. However, the tonic seizures induced by L-Cysteine were prevented by pretreatment with N(G)-nitro-L-arginine. Although L-cysteine (0.5, 1, 2.5, 5, 10 micromol/brain, i.c.v.) also caused a wild running (WR), NNA did not affect behavior. These results suggest that an overproduction of NO may be involve in the development of tonic seizures but not WR induced by L-cysteine.