Extracellular ATP stimulates polyphosphoinositide hydrolysis and prostaglandin synthesis in rat renal mesangial cells. Involvement of a pertussis toxin-sensitive guanine nucleotide binding protein and feedback inhibition by protein kinase C.
ATP stimulated a rapid and dose-dependent formation of inositol polyphosphates in rat glomerular mesangial cells. In parallel there was a 80% increase in 1, 2-diacylglycerol (DAG) after 15 s upon stimulation with ATP. The rank order of potency of a series of ATP and ADP analogues for stimulation of inositol trisphosphate (InsP3) formation was ATP greater than ATP gamma S greater than beta gamma-methylene-ATP greater than beta gamma-imido-ATP greater than ADP, while ADP beta S, AMP, adenosine and GTP were inactive, indicating the presence of P2y-purinergic receptors. ATP also stimulated a marked synthesis of prostaglandin E2 (PGE2). The rank order of potency of different ATP and ADP analogues was identical to that of InsP3 generation. Pre-treatment of the cells with pertussis toxin strongly attenuated ATP-induced formation of InsP3 and DAG. Short-term (10 min) pre-treatment of the cells with 12-O-tetradecanoylphorbol 13-acetate (TPA), a potent activator of protein kinase C, produced a dose-dependent inhibition of the ATP-stimulated InsP3 generation. Furthermore, inhibition of protein kinase C by the potent inhibitor staurosporin, or downregulation of protein kinase C by longterm (24 h) incubation of the cells with TPA, resulted in an enhanced formation of InsP3 towards a stimulation with ATP.
Pfeilschifter
J
J
Research Department, Ciba-Geigy Ltd, Basel, Switzerland.
D000255:Adenosine Triphosphate / Q000378:metabolism / Q000494:pharmacology*; D000818:Animals; D002478:Cells, Cultured; D004075:Diglycerides / Q000378:metabolism; D015232:Dinoprostone / Q000096:biosynthesis*; D015536:Down-Regulation; D005246:Feedback; D019204:GTP-Binding Proteins / Q000378:metabolism*; D005920:Glomerular Mesangium / Q000166:cytology / Q000378:metabolism*; D007295:Inositol Phosphates / Q000378:metabolism; D037342:Pertussis Toxin; D010716:Phosphatidylinositols / Q000378:metabolism*; D011493:Protein Kinase C / Q000378:metabolism; D051381:Rats; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D013997:Time Factors; D010566:Virulence Factors, Bordetella / Q000494:pharmacology
C011439:1,2-diacylglycerol; D004075:Diglycerides; D007295:Inositol Phosphates; D010716:Phosphatidylinositols; D010566:Virulence Factors, Bordetella; D000255:Adenosine Triphosphate; D037342:Pertussis Toxin; D011493:Protein Kinase C; D019204:GTP-Binding Proteins; D015232:Dinoprostone; D013755:Tetradecanoylphorbol Acetate