The endozepine ODN stimulates polyphosphoinositide metabolism in rat astrocytes

Astrocytes synthesize a series of peptides called endozepines which act as endogenous ligands of benzodiazepine receptors. The present study demonstrates that the endozepine ODN causes a dose-dependent increase in inositol trisphosphate and a parallel decrease in phosphatidylinositol bisphosphate in cultured rat astrocytes. Pre-incubation of astrocytes with the phospholipase C inhibitor U 73122 or with pertussis toxin totally blocked polyphosphoinositide metabolism. These data show that, in rat astrocytes, ODN stimulates a phospholipase C coupled to a pertussis toxin-sensitive G protein.