SUSCEPTIBILITY TO APOPTOSIS IS ENHANCED IN IMMATURE CORTICAL-NEURONS

The susceptibility of cortical neurons to two forms of apoptotic death was compared with susceptibility to excitotoxic death during developm ent in vitro (DIV 4-21). Murine cortical cultures were exposed for 48 h to the phosphatase inhibitor cyclosporine, the protein kinase inhibi tor staurosporine or the excitotoxin N-methyl-D-aspartate (NMDA). Susc eptibility to apoptosis induced by staurosporine or cyclosporine was m aximal between DIV 4-10 and declined from DIV 10 through 18. The oppos ite pattern was observed with susceptibility to NMDA receptor-mediated excitotoxic necrosis, which was minimal at DIV 6 and progressively in creased through DIV 21.