Ketamine suppresses both bicuculline- and picrotoxin-induced generalized tonic-clonic seizures during ontogenesis.

An anticonvulsant action of ketamine, a noncompetitive N-methyl-D-aspartate (NMDA) antagonist (5-40 mg/kg IP), on the bicuculline-induced (3-8 mg/kg IP) or picrotoxin-induced seizures (3-6 mg/kg IP) was assessed in male Wistar rats aged 7, 12, 18, 25 and 90 days. Ketamine alone caused moderate ataxia which was more pronounced in younger animals. In combination with both aforementioned convulsants, ketamine exerted anticonvulsant effects against generalized tonic-clonic seizures in all developmental stages studied. This effect was more pronounced in bicuculline-treated animals. Moreover, ketamine also suppressed the lethality induced by both drugs during all the development. On the contrary, the action of ketamine on minimal (clonic) seizures was moderate or absent. Our results suggest an important role of ketamine-affected transmission in the generation of the generalized tonic-clonic seizure pattern; moreover, an action of high doses of ketamine on GABA-A receptors might be present.