title: Cyclic ADP ribose-mediated Ca2+ signaling in mediating endothelial nitric oxide production in bovine coronary arteries.
abstract: The present study tested the hypothesis that cyclic ADP ribose (cADPR) serves as a novel second messenger to mediate intracellular Ca2+ mobilization in coronary arterial endothelial cells (CAECs) and thereby contributes to endothelium-dependent vasodilation. In isolated and perfused small bovine coronary arteries, bradykinin (BK)-induced concentration-dependent vasodilation was significantly attenuated by 8-bromo-cADPR (a cell-permeable cADPR antagonist), ryanodine (an antagonist of ryanodine receptors), or nicotinamide (an ADP-ribosyl cyclase inhibitor). By in situ simultaneously fluorescent monitoring, Ca2+ transient and nitric oxide (NO) levels in the intact coronary arterial endothelium preparation, 8-bromo-cADPR (30 microM), ryanodine (50 microM), and nicotinamide (6 mM) substantially attenuated BK (1 microM)-induced increase in intracellular [Ca2+] by 78%, 80%, and 74%, respectively, whereas these compounds significantly blocked BK-induced NO increase by about 80%, and inositol 1,4,5-trisphosphate receptor blockade with 2-aminethoxydiphenyl borate (50 microM) only blunted BK-induced Ca2+-NO signaling by about 30%. With the use of cADPR-cycling assay, it was found that inhibition of ADP-ribosyl cyclase by nicotinamide substantially blocked BK-induced intracellular cADPR production. Furthermore, HPLC analysis showed that the conversion rate of beta-nicotinamide guanine dinucleotide into cyclic GDP ribose dramatically increased by stimulation with BK, which was blockable by nicotinamide. However, U-73122, a phospholipase C inhibitor, had no effect on this BK-induced increase in ADP-ribosyl cyclase activity for cADPR production. In conclusion, these results suggest that cADPR importantly contributes to BK- and A-23187-induced NO production and vasodilator response in coronary arteries through its Ca2+ signaling mechanism in CAECs.
authors.affiliation: Department of Pharmacology and Toxicology, Medical College of Virginia, Virginia Commonwealth University, 410 N 12th St., Richmond, Virginia 23298, USA.
authors.forename: Guo
authors.initials: G
authors.lastname: Zhang
authors.forename: Eric G
authors.initials: EG
authors.lastname: Teggatz
authors.forename: Andrew Y
authors.initials: AY
authors.lastname: Zhang
authors.forename: Matthew J
authors.initials: MJ
authors.lastname: Koeberl
authors.forename: Fan
authors.initials: F
authors.lastname: Yi
authors.forename: Li
authors.initials: L
authors.lastname: Chen
authors.forename: Pin-Lan
authors.initials: PL
authors.lastname: Li
mesh_terms: D000818:Animals; D002118:Calcium / Q000378:metabolism*; D020013:Calcium Signaling / Q000502:physiology*; D002417:Cattle; D002478:Cells, Cultured; D003331:Coronary Vessels / Q000502:physiology*; D036563:Cyclic ADP-Ribose / Q000378:metabolism*; D042783:Endothelial Cells / Q000502:physiology*; D004730:Endothelium, Vascular / Q000502:physiology*; D066298:In Vitro Techniques; D009569:Nitric Oxide / Q000378:metabolism*; D015398:Signal Transduction / Q000502:physiology
chemical_list: D036563:Cyclic ADP-Ribose; D009569:Nitric Oxide; D002118:Calcium