Aggravation of DMCM-induced seizure by nitric oxide synthase inhibitors in mice

The present study investigated the effects of nitric oxide synthase (NOS) inhibitors on the seizure threshold of DMCM in mice. The seizure threshold of DMCM was evaluated using an intravenous infusion technique. The threshold of DMCM was significantly decreased by pretreatment with N-nitro- L-arginine (NOARG; 8 mg/kg) and N-nitro-L-arginine methyl aster (L-NAME; 100 mg/kg), but not with D-NAME. Furthermore, these NOS inhibitors also d ease the threshold for pentylenetetrazole-induced seizure. However, the threshold for caffeine-induced seizure was not affected by NOARG. These results suggest that the endogenous NO system may play an important role in the expression of seizure by GABA(A) receptor inhibitory agents (DMCM and PTZ).