LACK OF FOS-LIKE IMMUNOREACTIVITY AFTER SPONTANEOUS SEIZURES OR REINDUCTION OF STATUS EPILEPTICUS BY PILOCARPINE IN RATS

Acute seizures and status epilepticus induced by pilocarpine lead to t he expression of Fos-like immunoreactivity in several specific brain a reas in a manner similar to that of other models of limbic seizures. U pon development of status epilepticus after systemic pilocarpine injec tion, animals develop a state where chronic spontaneous seizures recur . Assessment of Fos-like immunoreactivity after such spontaneous seizu res or after status epilepticus reinduction reveals either lack of sta ining or a weak reaction in a few brain areas including the ventral ti p of the dentate gyrus, prepiriform, lateral piriform and perirhinal c ortices, and scattered locations throughout temporal neocortex. Our re sults suggest that status epiiepticus induction may lead to a long-las ting state of Fos down-regulation.