Stringer J L
Department of Pharmacology, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA.
Epilepsy Res. 2000 Jul;40(2-3):147-53. doi: 10.1016/s0920-1211(00)00118-2.
Topiramate is a relatively new antiepileptic drug with several putative anticonvulsant mechanisms. Among them is the ability to inhibit carbonic anhydrase, a property in common with the anticonvulsant acetazolamide. This study examined the effects of topiramate and acetazolamide on the duration of epileptiform activity and on paired-pulse inhibition in the dentate gyrus in urethane anesthetized adult Sprague-Dawley rats. Neither topiramate nor acetazolamide altered excitability in the dentate gyrus, as measured with input-output curves or induction of long-term potentiation. Topiramate increased paired-pulse inhibition, whereas acetazolamide had no effect. Both drugs dose-dependently blocked the lengthening of the duration of epileptiform activity compared to vehicle controls. These results indicate that topiramate has an anticonvulsant-related effect (increase in paired-pulse inhibition), which may contribute to its antiepileptic effect, that is not dependent on its ability to inhibit carbonic anhydrase.
