The amounts of mRNAs for proto-oncogene c-fos and structural protein beta-actin were measured in the rat cerebral cortex after transient forebrain ischemia. A transient and specific induction of c-fos mRNA was noticed in the cerebral cortex 30-90 min after ischemia followed by decline to control value. In contrast, the level of mRNA for beta-actin was not altered throughout the recirculation period examined. These results suggest specific role of c-fos gene after brain damage.