Protective effects of calcium ions via L-type calcium channels and NMDA receptors on prostaglandin E2-induced apoptosis in rat cortical cells

Calcium ions mediate a variety of physiological responses of developing neurons including survival. The purpose of this study was to examine the effect of calcium influx through L-type calcium channels (LTCCs) or NMDA receptors on prostaglandin E2 (PGE2)-induced apoptosis in rat cortical cells. Cultures of rat cortical cells were prepared from an embryonic day 18 rat neocortex. After culturing for 2 or 8 days in vitro (DIV), the cells were subjected to PGE2 treatment for 48 h. FPL64176, an LTCC agonist, protected the cells at 2 and 8 DIV from PGE2-induced apoptosis. On the other hand, N-methyl-D-aspartate (NMDA), an agonist of NMDA receptor, protected the cells from PGE2-induced apoptosis only at 8 DIV. FPL64176 increased the calcium levels at 2 and 8 DIV, whereas NMDA increased the calcium levels only at 8 DIV. The protective effects of the LTCC agonist and NMDA on PGE2-induced apoptosis were blocked following treatment of the cells with protein kinase C inhibitors. Our results suggest that LTCCs and NMDA receptors modulate the cell death of developing cortical neurons possibly through a protein kinase C pathway.