David H. Tedeschi

Postictal Recovery in Normal and Diphenylhydantoin (Dilantin)-Treated Mice.∗:

Summary In order to study postictal recovery, groups of normal and Dilantin-treated mice were given a supramaximal electroshock and the durations of the hindleg components of the “first” seizure recorded. At various time intervals after the “first” seizure, a “second” supramaximal electroshock was given and the durations of the hindleg components of the “second” seizure recorded. This procedure was repeated, with longer time intervals between seizures, until the observed durations of the “second” seizure components were not significantly different from their “first” seizure values. In addition, the time (RT50) required for 50% of animals to recover ability to exhibit a second tonicclonic seizure after a first was determined. The data obtained may be summarized as follows: The order in which the durations of the various components and the total duration of the “second” seizure returned to their “first” seizure values were the same in both groups: total seizure duration, terminal clonus, tonic extension, and tonic flexion. The total duration of a maximal seizure is relatively independent of marked changes in duration of the individual seizure components. Dilantin prolonged the recovery time of terminal clonus, tonic extension, and tonic flexion by approximately 300%, 150%, and 170%, respectively. In addition, Dilantin prolonged RT50 by 325%. Evidence is presented which suggests that Dilantin acts to prolong the latent period before recovery of the tonic-extensor component starts, and that the recovery process per se, once initiated, is relatively unaffected by the drug.