Signal transduction pathways coupled to a P2U receptor in neuroblastoma × glioma (NG108-15) cells

摘要: Extracellular ATP has neurotransmitter-like properties in the CNS and PNS that are mediated by a cell-surface P2 purinergic receptor. In present study, we have extensively characterized signal transduction pathways associated with activation of P2U receptor cultured neuroblastoma x glioma hybrid cell line (NG108-15 cells). The addition > or = 1 microM to NG108-15 cells caused transient increase [Ca2+]i was inhibited 40% when extracellular calcium chelated EGTA. concentrations 500 also elicited sustained occurred concomitantly hydrolysis [32P]-phosphatidylinositol 4,5-bisphosphates an level inositol 1,4,5-trisphosphate. time- dose-dependent levels [3H]inositol monophosphates lithium-treated cells. Separation monophosphate isomers ion chromatography revealed specific 4-monophosphate. magnitude correlated concentration fully ionized form (ATP4-) medium not magnesium-ATP (MgATP2-). Similar ATP, UTP induced polyphosphoinositide breakdown, phosphate formation, [Ca2+]i. ADP, ITP, TTP, GTP, gamma S, 2-methylthio beta, gamma-imidoATP 3'-O-(4-benzoyl)benzoylATP, but CTP, AMP, gamma-methylene adenosine, labeled [32P]P(i) [14C]-arachidonic acid, phosphatidic acids, had no effect on arachidonic acid. acid apparently due phospholipase D because did induce formation phosphatidylethanol [14C]myristic acid-labeled incubated presence ethanol. These findings support hypothesis nucleotide is coupled pathway involving C plasma membrane channel, phospholipases A2 D.