title: Nitric oxide modulates superoxide release and peroxynitrite formation in human blood vessels.
abstract: Nitric oxide and superoxide have important roles as vascular signaling molecules. Nitric oxide (NO) reacts rapidly with superoxide, producing peroxynitrite. The relative balance between these radicals has important implications for vascular pathophysiology in hypertension and other vascular disease states. However, the relationships between superoxide, NO, and peroxynitrite formation in human blood vessels remain unclear. Accordingly, we systematically measured NO, superoxide, and peroxynitrite production from human internal mammary arteries, radial arteries, and saphenous veins from 78 patients undergoing coronary bypass surgery. Basal superoxide release was detected in all vessels at similar levels. However, endothelial removal or nitric oxide synthase inhibition increased mean superoxide release, with a corresponding reduction in peroxynitrite formation. Conversely, NO donors and superoxide scavengers both reduced superoxide release, whereas only NO donors increased peroxynitrite formation. These changes were much larger in arteries that in veins, but there were striking correlations between superoxide production, NO bioavailability, and peroxynitrite formation between the vessel types. Our findings provide direct evidence for coordinated vascular signaling mediated by interactions between NO, superoxide, and peroxynitrite and have important implications for studies of the functional effects of these radicals in human blood vessels.
authors.affiliation: Department of Cardiovascular Medicine, University of Oxford, John Radcliffe Hospital, United Kingdom.
authors.forename: Tomasz J
authors.initials: TJ
authors.lastname: Guzik
authors.forename: Nick E J
authors.initials: NE
authors.lastname: West
authors.forename: Ravi
authors.initials: R
authors.lastname: Pillai
authors.forename: David P
authors.initials: DP
authors.lastname: Taggart
authors.forename: Keith M
authors.initials: KM
authors.lastname: Channon
mesh_terms: D014013:1,2-Dihydroxybenzene-3,5-Disulfonic Acid Disodium Salt / Q000494:pharmacology; D001158:Arteries / Q000187:drug effects / Q000378:metabolism; D001808:Blood Vessels / Q000378:metabolism*; D046508:Culture Techniques; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005260:Female; D016166:Free Radical Scavengers / Q000494:pharmacology; D006801:Humans; D008297:Male; D008875:Middle Aged; D009569:Nitric Oxide / Q000502:physiology*; D020030:Nitric Oxide Donors / Q000494:pharmacology; D019001:Nitric Oxide Synthase / Q000037:antagonists & inhibitors; D009599:Nitroprusside / Q000494:pharmacology; D030421:Peroxynitrous Acid / Q000096:biosynthesis*; D013481:Superoxides / Q000378:metabolism*; D014652:Vascular Diseases / Q000378:metabolism; D014680:Veins / Q000187:drug effects / Q000378:metabolism; D019323:omega-N-Methylarginine / Q000494:pharmacology
chemical_list: D004791:Enzyme Inhibitors; D016166:Free Radical Scavengers; D020030:Nitric Oxide Donors; D013481:Superoxides; D030421:Peroxynitrous Acid; D009599:Nitroprusside; D019323:omega-N-Methylarginine; D009569:Nitric Oxide; D014013:1,2-Dihydroxybenzene-3,5-Disulfonic Acid Disodium Salt; D019001:Nitric Oxide Synthase