Selective induction of Kunitz-type protease inhibitor domain-containing amyloid precursor protein mRNA after persistent focal ischemia in rat cerebral cortex

An induction of amyloid precursor protein (APP) mRNA was examined in a middle cerebral artery occlusion model of rats using Northern blot analyses. The level of tubulin mRNA was measured as an internal standard. With persistent focal ischemia, APP mRNA species which contain a Kunitz-type protease inhibitor (KPI) domain were induced in the rat cerebral cortex from 1 to 21 days after the insult with a maximum at 4 days, while total amounts of APP mRNA did not change. No change was observed in the level of tubulin mRNA. These results suggest a selective role of APP species which contain the KPI domain in focal cerebral ischemia.