1-Oleoyl-2-acetyl-glycerol and phorbol diester stimulate Ca2+ influx through Ca2+ channels in neuroblastoma x glioma hybrid NG108-15 cells.

The effect of 1-oleoyl-2-acetyl-glycerol (OAG) and the phorbol diester 12-O-tetradecanoyl-phorbol-acetate (TPA) on the intracellular Ca2+ concentration ([Ca2+]i) in NG108-15 cells was studied using a Ca2+ indicator, quin 2. OAG and TPA induced an increase in [Ca2+]i from 100 +/- 19 to 187 +/- 24 nM and 192 +/- 15 nM, respectively, within 15 min. The increase in [Ca2+]i induced by activators of protein kinase C was dependent on the extracellular Ca2+ concentration [Ca2+]o) and was inhibited by the Ca2+ blockers, verapamil and nifedipine. These results indicate that the OAG- and TPA-induced [Ca2+]i increase is mediated by the influx of extracellular Ca2+ through voltage-sensitive Ca2+ channels.