WIDESPREAD NEURONAL EXPRESSION OF C-FOS THROUGHOUT THE BRAIN AND LOCAL EXPRESSION IN GLIA FOLLOWING A HIPPOCAMPAL INJURY

Fos oncoprotein is an immediate early gene product and a marker of cel l activation following a variety of insults. We have previously shown that a mechanical lesion to the hippocampus of adult mice induces a ne uronal expression of the cytokines interleukin-1 alpha (IL-1 alpha) an d tumor necrosis factor-alpha (TNF alpha) whereas a lesion to the stri atum does not. The role of these inflammatory cytokines in the pathoph ysiology of central neurons is still unclear. The present work was und ertaken to study a possible correlation between the central expression patterns of c-Fos on the one hand and IL-1 alpha and TNF alpha on the other hand. We show that Fos is expressed in a majority of brain neur ons after a unilateral lesion to the hippocampus whereas it is confine d to the site of injury when applied to the striatum, as previously de scribed for the expression of the cytokines. (C) 1997 Elsevier Science Ireland Ltd.