INDUCTION OF FOS AND JUN PROTEINS DURING FOCAL EPILEPSY - CONGRUENCESWITH AND DIFFERENCES TO [C-14] DEOXYGLUCOSE METABOLISM

fos and jun belong to multigene families coding for transcription fact ors. These cellular immediate-early genes (IEGs) are thought to be inv olved in coupling neuronal excitation to changes of target gene expres sion. Immunocytochemistry with specific antisera was used to assess re gional levels of five IEG-encoded proteins (c-FOS, FOS B, c-JUN, JUN B and JUN D) in a rat model of penicillin-induced focal epilepsy. To as sess whether brain regions with post-ictal de novo transcription facto r synthesis correspond to those areas with increased glucose metabolis m, IEG expression patterns were compared with [C-14]deoxyglucose autor adiography performed in a subset of animals. The results demonstrated marked induction of c-FOS, FOS B, c-JUN and JUN B but not JUN D in the cortical epileptic focus. Thereby, individual IEG-encoded proteins ex hibited differential temporal and spatial expression patterns. Within the epileptic focus, IEG expression correlated with increased glucose metabolism. In contrast, IEG induction was not observed in brain areas distant from the epileptic focus that also demonstrated increased glu cose metabolism, such as homotopic contralateral motor cortex and ipsi lateral thalamic nuclei. These findings indicate that in focal epileps y changes of the genetic programme are restricted to neurons of the ep ileptic focus. In contrast, the increased [C-14]deoxyglucose metabolis m in contralateral motor cortex and ipsilateral thalamus seems to indi cate functional changes.