P. Gass et al., INDUCTION OF FOS AND JUN PROTEINS DURING FOCAL EPILEPSY - CONGRUENCESWITH AND DIFFERENCES TO [C-14] DEOXYGLUCOSE METABOLISM, Molecular brain research, 46(1-2), 1997, pp. 177-184
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.