title: Ceramide reduces endothelium-dependent vasodilation by increasing superoxide production in small bovine coronary arteries.
abstract: Ceramide serves as a second messenger in a variety of mammalian cells. Little is known regarding the role of ceramide in the regulation of vascular endothelial function. The present study was designed to determine whether ceramide affects endothelium-dependent vasodilation in coronary arteries and to explore the mechanism of action of ceramide. In isolated and pressurized small bovine coronary arteries, cell-permeable C(2)-ceramide (10(-)(5) mol/L) markedly attenuated vasodilator responses to bradykinin and A23187 (by 40% and 60%, respectively). In the presence of K(G)-nitro-L-arginine methyl ester, ceramide produced no further inhibition on the vasodilation induced by these vasodilators. Ceramide had no effect on DETA NONOate-induced vasodilation. By use of a fluorescence NO indicator (4,5-diaminofluorescein diacetate), intracellular NO was measured in the endothelium of freshly isolated small coronary arteries. It was found that ceramide significantly inhibited bradykinin-induced NO increase within endothelial cells. However, it had no effect on the activity of arterial or endothelial NO synthase. Pretreatment of the arteries with sodium dihydroxybenzene disulfonate (Tiron, 10(-)(3) mol/L), a cell-permeable superoxide scavenger, or polyethylene glycol superoxide dismutase (100 U/mL) largely restored the inhibitory effects of ceramide on the vasodilation and NO increase induced by bradykinin or A23187. Moreover, ceramide time-dependently increased intracellular superoxide (O(2)(-. )) in the endothelium, as measured by a fluorescent O(2)(-. )indicator, dihydroethidium. These results demonstrate that ceramide inhibits endothelium-dependent vasodilation in small coronary arteries by decreasing NO in vascular endothelial cells and that this decrease in NO is associated with increased O(2)(-. ) but not with the inhibition of NO synthase activity within these cells.
authors.affiliation: Department of Pharmacology, Medical College of Wisconsin, Milwaukee, USA.
authors.forename: D X
authors.initials: DX
authors.lastname: Zhang
authors.forename: A P
authors.initials: AP
authors.lastname: Zou
authors.forename: P L
authors.initials: PL
authors.lastname: Li
mesh_terms: D014013:1,2-Dihydroxybenzene-3,5-Disulfonic Acid Disodium Salt / Q000494:pharmacology; D000818:Animals; D001158:Arteries / Q000187:drug effects / Q000378:metabolism; D001920:Bradykinin; D000001:Calcimycin / Q000494:pharmacology; D002417:Cattle; D002518:Ceramides / Q000378:metabolism* / Q000494:pharmacology; D002956:Citrulline / Q000096:biosynthesis; D003331:Coronary Vessels / Q000187:drug effects / Q000378:metabolism*; D004730:Endothelium, Vascular / Q000187:drug effects / Q000378:metabolism*; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005456:Fluorescent Dyes; D016166:Free Radical Scavengers / Q000494:pharmacology; D066298:In Vitro Techniques; D007424:Intracellular Fluid / Q000378:metabolism; D019331:NG-Nitroarginine Methyl Ester / Q000494:pharmacology; D009569:Nitric Oxide / Q000378:metabolism; D019001:Nitric Oxide Synthase / Q000378:metabolism; D013110:Sphingosine / Q000031:analogs & derivatives / Q000378:metabolism / Q000494:pharmacology; D013482:Superoxide Dismutase / Q000378:metabolism / Q000494:pharmacology; D013481:Superoxides / Q000378:metabolism* / Q000494:pharmacology; D014664:Vasodilation / Q000187:drug effects / Q000502:physiology*
chemical_list: D002518:Ceramides; D004791:Enzyme Inhibitors; D005456:Fluorescent Dyes; D016166:Free Radical Scavengers; C064769:N-acetylsphingosine; D013481:Superoxides; D002956:Citrulline; D009569:Nitric Oxide; D000001:Calcimycin; D014013:1,2-Dihydroxybenzene-3,5-Disulfonic Acid Disodium Salt; D019001:Nitric Oxide Synthase; D013482:Superoxide Dismutase; D013110:Sphingosine; D001920:Bradykinin; D019331:NG-Nitroarginine Methyl Ester