ABSENCE OF A PERSISTENTLY ELEVATED 37 KDA FOS-RELATED ANTIGEN AND AP-1-LIKE DNA-BINDING ACTIVITY IN THE BRAINS OF KAINIC ACID-TREATED FOSB NULL MICE

Chronic stimulation of the nervous system or acute administration or k ainic acid results in a persistent increase in AP-1-like DNA-binding a ctivity in the brain. However, the composition and function of these A P-1 complexes remain controversial. By comparing wild-type and fosB-nu ll mice treated with kainic acid, we establish that the complexes comp rise JunD in association with an similar to 37 kDa Delta-FosB species. Delta-FosB was expressed persistently in neurons in many areas of the CNS, even though fosB mRNA only increased transiently. This implies t hat the 37 kDa protein is very stable. FosB-/- mice are predisposed to seizures. Therefore, the chronic expression of Delta-FosB elicited by kainic acid seizures may be indicative of a compensatory/protective r ole in the pathophysiology of epilepsy.