Effect of topiramate on cognitive function and single units from hippocampal place cells following status epilepticus

Topiramate, an antiepileptic drug with multiple mechanisms of action, was assessed as a neuroprotective agent following status epilepticus. We administered topiramate or normal saline chronically beginning 1 hour after cessation of lithium pilocarpine-induced status epilepticus. Control animals not subjected to status epilepticus were also treated with topiramate or normal saline. Following completion of the topiramate treatment, animals were tested in the water maze to assess spatial learning and underwent in vivo single-cell place cell recordings. Spontaneous seizure frequency following status epilepticus in the topiramate-treated rats was similar to that in the rats treated with saline. Following status epilepticus, rats had profound deficits in water maze performance and place cell function. Rats subjected to status epilepticus and treated with topiramate were also severely impaired in the water maze, but performed slightly better than rats treated with saline. Following status epilepticus, topiramate-treated rats did not differ from rats treated with normal saline in the platform switch, a test of prefrontal function. Although place cell firing patterns were similar in both the topiramate- and saline-treated rats, rats treated with topiramate had higher information content scores than rats treated with saline. Topiramate-treated animals had less supragranular sprouting following status epilepticus than nontreated rats. Control animals treated with topiramate did not differ from saline-treated controls on any measures. Taken together, this study shows that topiramate administered following status epilepticus has modest neuroprotective effects.