Induction of c-fos mRNA expression by afterdischarge in the hippocampus of naive and kindled rats

J Neurochem. 1990 Sep;55(3):1050-5. doi: 10.1111/j.1471-4159.1990.tb04595.x.


Periodic induction of focal electrical seizure [afterdischarge (AD)] is an absolute prerequisite for the development of kindling, an animal model of complex partial epilepsy. Once established, it is a permanent condition. The mechanism(s) that translate ADs, which last tens of seconds, into life-long alterations in the CNS is unclear. Cellular immediate-early genes have been implicated in the conversion of short-term stimuli to long-term alterations in cellular phenotypes by regulating target gene expression. We have investigated the contribution of one such early gene, c-fos, to this process. The relationship between ADs and expression of c-fos gene in the rat hippocampus, a key structure in kindling development, was studied by analysis of mRNA levels. The low constitutive expression of c-fos mRNA in the hippocampus was not altered by kindling. There was an "all-or-none" relationship between induction of c-fos and the duration of AD. The threshold for induction was approximately 30 s of AD. Above-threshold ADs induced c-fos in both naive and kindled animals to the same extent and with identical temporal profiles. Although the expression of c-fos is unchanged with kindling, c-fos may nonetheless contribute to many long-term changes of kindling, both adaptive and epileptogenic.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • Electroencephalography
  • Gene Expression*
  • Hippocampus / metabolism*
  • Kindling, Neurologic / physiology*
  • Kinetics
  • Proto-Oncogene Proteins / genetics*
  • Proto-Oncogene Proteins c-fos
  • RNA, Messenger / genetics*
  • Rats
  • Rats, Inbred Strains
  • Seizures / metabolism*


  • Proto-Oncogene Proteins
  • Proto-Oncogene Proteins c-fos
  • RNA, Messenger