The influence of glucocorticoids on the transcription factor NFkB was
investigated by using the gel mobility shift assay with nuclear extrac
ts prepared from rat cerebral cortex and hippocampus after a variety o
f in vivo treatments. Following stimulation with each of three treatme
nts, kainate, pilocarpine, or lithium plus pilocarpine-induced seizure
s, NFkB DNA binding activity was significantly greater in the cortex a
nd hippocampus from adrenalectomized than from adrenal-intact rats. Th
ese results indicate that in rat brain glucocorticoids inhibit NfkB ac
tivity in addition to the previously reported inhibition of the transc
ription factor AP-1 (activator protein 1). Impairment of stimulus-indu
ced transcription factor activity may contribute to the deleterious ef
fects of prolonged elevations of glucocorticoids on neuronal function.