SUPPRESSIVE EFFECT OF E-64C ON ISCHEMIC DEGRADATION OF CEREBRAL PROTEINS FOLLOWING OCCLUSION OF THE MIDDLE CEREBRAL-ARTERY IN RATS

Microtubule-associated protein 2 (MAP2) levels in the left cerebral hemisphere decreased significantly 3 days after occlusion of the left middle cerebral artery in rats to 29 ± 16.3% of control levels. Since MAP2 is one of the substrates of calpain, E-64c, a synthetic calpain inhibitor, was administered at a dose of 400 mg/kg twice a day for 3 days, with the first dose being given before the production of ischemia. This depletion was significantly inhibited in vivo by E-64c (P < 0.05) to increase MAP2 levels to 55 ± 25.7% of control levels. E-64c had no significant effect on the ischemia-induced depletion of myelin-associated glycoprotein. Sham-operated rats were used as controls. Our results suggest that calpain is partially involved in the degradation of MAP2, and that the use of calpain inhibitors can be a useful clinical approach to cerebral ischemia. © 1990.