EARLY, BUT NOT LATE, ANTIEPILEPTIC TREATMENT REDUCES RELAPSE OF SOUND-INDUCED SEIZURES IN THE POSTISCHEMIC RAT

Global ischemia was used to induce a sensitivity to sound-triggered ge neralized seizures in 24 male Long-Evans rats. All showed a generalize d seizure when exposed to a 108 dB bell for 1 min. They were assigned randomly to 3 groups of 8, and received 30 additional sound exposures. The early treatment group was injected with valproate (200 mg/kg i.p) 1 h prior to each of the first 10 sound exposures. The late treatment group received the same treatment during the second set of 10 sound e xposures after 10 sound exposures without treatment. The third group w as untreated. Both early and late treated groups had a significant red uction in seizure incidence during the treatment period, i.e. both gro ups showed seizure control. However, in the late group seizures return ed promptly when valproate treatment was discontinued, while the early group showed a sustained reduction in seizure susceptibility. Since t his outcome corresponds to seizure remission, the findings of this stu dy favor early treatment.