title: Hypertension alters the participation of contractile prostanoids and superoxide anions in lipopolysaccharide effects on small mesenteric arteries.
abstract: The involvement of cyclooxygenase-2 (COX-2)-derived products and superoxide anion in the effect of lipopolysaccharide in noradrenaline (NA)-induced contraction was investigated in small mesenteric arteries (SMA) from normotensive, Wistar Kyoto (WKY), and spontaneously hypertensive (SHR) rats. In WKY, lipopolysaccharide (10 microg/ml, 1 and 5 h) only inhibited the NA response (0.1-30 microM) in the presence of dexamethasone (1 microM), indomethacin (10 microM), the selective COX-2 inhibitor, NS 398 (10 microM), and the TXA(2)/PGH(2) receptor antagonist, SQ 29,548 (10 microM) but not of superoxide dismutase (SOD, 100 U/ml). In SHR, lipopolysaccharide inhibited the NA response by itself; this inhibition was potentiated by dexamethasone, indomethacin, NS 398, SQ 29,548 and SOD. The effect of lipopolysaccharide plus indomethacin, NS 398 or SQ 29,548 was higher in SMA from WKY than SHR only after 1 h lipopolysaccharide incubation. N(G)-nitro-L-arginine methyl ester (100 microM) and endothelium removal abolished the indomethacin-induced potentiatory effect of lipopolysaccharide in both strains. Endothelium removal also abolished the SOD potentiatory effect in SMA from SHR. Lipopolysaccharide increases COX-2 expression to a similar level in both strains and iNOS expression in a greater extent in SHR; these increases were reduced by dexamethasone. These results indicate: 1) lipopolysaccharide induces the endothelial production of contractile prostanoids from COX-2 in SMA, probably to compensate the increase in NO from iNOS; 2) the production of prostanoids in the presence of lipopolysaccharide seems to be greater in normotensive than hypertensive rats only after lipopolysaccharide short incubation times; 3) endothelial production of O(2)(.-) contributes to counteract depression of NA contraction caused by lipopolysaccharide only in SHR.
authors.affiliation: Depto. de Farmacología y Terapéutica, Facultad de Medicina, Universidad Autónoma de Madrid, C/ Arzobispo Morcillo 4, 28029 Madrid, Spain.
authors.forename: Ana M
authors.initials: AM
authors.lastname: Briones
authors.forename: María J
authors.initials: MJ
authors.lastname: Alonso
authors.forename: Raquel
authors.initials: R
authors.lastname: Hernanz
authors.forename: Silvia
authors.initials: S
authors.lastname: Tovar
authors.forename: Elisabet
authors.initials: E
authors.lastname: Vila
authors.forename: Mercedes
authors.initials: M
authors.lastname: Salaices
mesh_terms: D000818:Animals; D019086:Bridged Bicyclo Compounds, Heterocyclic; D051546:Cyclooxygenase 2; D003907:Dexamethasone / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D004338:Drug Combinations; D005231:Fatty Acids, Unsaturated; D006834:Hydrazines / Q000494:pharmacology; D006973:Hypertension / Q000201:enzymology*; D066298:In Vitro Techniques; D007213:Indomethacin / Q000494:pharmacology; D007527:Isoenzymes / Q000037:antagonists & inhibitors / Q000096:biosynthesis*; D008070:Lipopolysaccharides / Q000494:pharmacology*; D008297:Male; D008638:Mesenteric Arteries / Q000187:drug effects / Q000201:enzymology* / Q000502:physiology; D051379:Mice; D009119:Muscle Contraction / Q000187:drug effects / Q000502:physiology; D009131:Muscle, Smooth, Vascular / Q000187:drug effects / Q000502:physiology; D019001:Nitric Oxide Synthase / Q000378:metabolism; D052247:Nitric Oxide Synthase Type II; D009578:Nitrobenzenes / Q000494:pharmacology; D009638:Norepinephrine / Q000494:pharmacology; D011451:Prostaglandin-Endoperoxide Synthases / Q000096:biosynthesis*; D051381:Rats; D011918:Rats, Inbred SHR; D011921:Rats, Inbred WKY; D017482:Receptors, Thromboxane / Q000037:antagonists & inhibitors; D013449:Sulfonamides / Q000494:pharmacology; D013482:Superoxide Dismutase / Q000494:pharmacology; D013928:Thromboxane A2 / Q000502:physiology*
chemical_list: D019086:Bridged Bicyclo Compounds, Heterocyclic; D004338:Drug Combinations; D005231:Fatty Acids, Unsaturated; D006834:Hydrazines; D007527:Isoenzymes; D008070:Lipopolysaccharides; D009578:Nitrobenzenes; D017482:Receptors, Thromboxane; D013449:Sulfonamides; C080955:N-(2-cyclohexyloxy-4-nitrophenyl)methanesulfonamide; D013928:Thromboxane A2; D003907:Dexamethasone; C045749:SQ 29548; D019001:Nitric Oxide Synthase; D052247:Nitric Oxide Synthase Type II; C496317:Nos2 protein, mouse; C496318:Nos2 protein, rat; D051546:Cyclooxygenase 2; D011451:Prostaglandin-Endoperoxide Synthases; D013482:Superoxide Dismutase; D009638:Norepinephrine; D007213:Indomethacin