title: P2 purinoceptor-stimulated conversion of arginine to citrulline in bovine endothelial cells is reduced by inhibition of protein kinase C.
abstract: Bovine aortic endothelial cells contain two coexisting receptors for extracellular ATP, named the P2Y and P2U purinoceptors. Previous studies have shown that these receptors are linked to phospholipase C in a manner that is modulated in part by protein kinase C (PKC). In this study, we investigate the influence of PKC in the regulation of endothelial nitric oxide synthase (NOS) by these two purinoceptors. Activation of either P2Y or P2U purinoceptors by either 2-methylthio-ATP or UTP, respectively, stimulated the formation of [3H]-citrulline in [3H]-arginine-labelled cells in a concentration-dependent manner. This stimulation was sensitive to inhibition by NG-nitro-L-arginine. Ten minutes of pretreatment with the PKC activator tetradecanoyl phorbol acetate (TPA) failed to affect NOS activity, either alone or when stimulated with 2-methylthio-ATP or UTP. However, under these conditions TPA caused almost complete translocation of PKC-alpha from the cytosol to the membrane. Ten minutes of pretreatment with the PKC inhibitor Ro 31-8220 significantly inhibited the agonist-induced stimulation of NOS. These results show that both P2Y and P2U purinoceptors stimulate endothelial NOS in a manner that is dependent on PKC activity.
authors.affiliation: Department of Cell Physiology and Pharmacology, University of Leicester, UK.
authors.forename: C A
authors.initials: CA
authors.lastname: Brown
authors.forename: V
authors.initials: V
authors.lastname: Patel
authors.forename: G
authors.initials: G
authors.lastname: Wilkinson
authors.forename: M R
authors.initials: MR
authors.lastname: Boarder
mesh_terms: D000818:Animals; D001120:Arginine / Q000378:metabolism*; D002417:Cattle; D002478:Cells, Cultured; D002956:Citrulline / Q000378:metabolism*; D004730:Endothelium, Vascular / Q000378:metabolism*; D009569:Nitric Oxide / Q000378:metabolism; D019001:Nitric Oxide Synthase / Q000378:metabolism; D011493:Protein Kinase C / Q000037:antagonists & inhibitors*; D018048:Receptors, Purinergic P2 / Q000502:physiology*; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology
chemical_list: D018048:Receptors, Purinergic P2; D002956:Citrulline; D009569:Nitric Oxide; D001120:Arginine; D019001:Nitric Oxide Synthase; D011493:Protein Kinase C; D013755:Tetradecanoylphorbol Acetate