CHOLECYSTOKININ-INDUCED SIGNALING IN RAT GLIOMA C-6 CELLS

We investigated the effect of sulphated cholecystokinin octapeptide (C CK-8S) on free intracellular calcium concentration, phosphatidylinosit ol metabolism, and protein phosphorylation in C-6 cells, a rat glioma cell line which was shown to express CCKB type receptors. Increase in [Ca2+](i) by both influx across the cell membrane and release from int ernal stores was demonstrated by utilizing a laser confocal imaging sy stem. Because CCK-8S produced a transient elevation of inositol tripho sphate level participation of InsP(3) in calcium signaling in C-6 cell s is very likely. Protein kinase C seems to be involved in CCK-8S indu ced signaling in rat glioma C-6 cells as demonstrated by using in vivo phosphorylation experiments.