TEMPORAL PATTERN OF AP-1 DNA-BINDING ACTIVITY IN THE RAT HIPPOCAMPUS FOLLOWING A KINDLED SEIZURE

DNA binding by transcripton factor AP-1 was enhanced remarkably follow ing kindling stimulation in rat amygdala. Maximum increase occurred 2h after stimulation with return to baseline within 24 h. Supershift and western analyses revealed that 38,000 mol. wt Fos-related antigen and JunD were the main components of the evoked AP-1 complexes at the tim e their induction reached maximum. AP-1 induction 2h after the last ki ndling stimulation was more prominent in samples from previously kindl ed rats than in those from non-kindled rats. This study sought to esta blish the role of AP-1 in plastic changes of the hippocampus associate d with kindling. Male Sprague-Dawley rats were kindled from the left a mygdala until they exhibited Racine(15) class 5 generalized seizures. Nuclear proteins were extracted from dorsal hippocampi obtained From 0 to 24 h after final stimulations. From these, we evaluated the tempor al pattern of DNA binding by AP-1 using a gel mobility-shift assay wit h a P-32-labelled AP-1 probe. Supershift and western analyses were add ed to investigate components of the seizure-evoked AP-1 complexes. Our results suggest that the basal level of AP-1 complexes is not associa ted with the seizure susceptibility in kindling. However, development of kindling appears to facilitate stimulus-evoked AP-1 induction, prob ably via plastic changes in the central nervous system. AP-1 may media te such changes by regulating expression of certain genes. (C) 1997 IB RO. Published by Elsevier Science Ltd.