Characteristics of flurothyl-induced seizures and the effect of antiepileptic drugs on flurothyl-induced seizures in Mongolian gerbils

We investigated the characteristics of the flurothyl-induced seizures and the effects of antiepileptic drugs on the flurothyl-induced seizure model in a previously untested Mongolian gerbil species. Mongolian gerbils demonstrated tonic extension immediately after or within 1 min after the appearance of clonic convulsion. Very high amplitude spike waves appeared in these regions concurrent with the appearance of clonic convulsion. When the tonic extension appeared immediately after the clonic convulsion, the high amplitude spike waves continued during tonic convulsion. When the tonic extension occurred, high amplitude spike waves appeared in these three regions within a very short time, and afterward Mongolian gerbils died. Administration of valproic acid-Na (200 mg/kg), ethosuximide (100 and 200 mg/kg), clonazepam (2 mg/kg) and diazepam (0.5, 1 and 2 mg/kg) significantly prolonged the latency of clonic convulsion. Zonisamide-Na, phenytoin and carbamazepine, however, had no such effect. In Mongolian gerbils, tonic extension was demonstrated immediately after the appearance of clonic convulsion, yet, this effect was inhibited by all these drugs in a dose-dependent manner. Diazepam completely blocked the appearance of any behavioral changes in animals. These findings suggest that diazepam has a significant effect on flurothyl-induced seizures. Flurothyl-induced convulsions are associated with GABA receptors; hence, benzodiazepine (BDP) suppression may result from the strong relation between BDP and GABAnergic neurons. (C) 2002 Elsevier Science Inc. All rights reserved.