title: Inducible L-arginine/nitric oxide pathway in human internal mammary artery and saphenous vein.
abstract: To characterize the L-arginine/nitric oxide (NO) pathway in human vascular smooth muscle (VSM), contractile responses of isolated internal mammary arteries (IMA) and saphenous veins (SV) were observed after induction of NO synthase by interleukin-1 beta (IL-1 beta) or by lipopolysaccharide (LPS). In IL-1 beta-treated endothelium-denuded rings, contractile responses to phenylephrine were reduced in SV rings only. Maximum phenylephrine-induced contraction was depressed by approximately 50%. This was not modified by the presence of indomethacin, NG-nitro-L-arginine methyl ester (L-NAME), or methylene blue (MeB). In LPS-treated vessels, contractile responses were depressed in both SV and IMA rings (40%), and this was not affected by indomethacin. In SV, L-NAME, NG-monomethyl-L-arginine, or MeB did not affect the inhibitory effect of LPS, whereas the effect was reversed in IMA by these inhibitors. In LPS-treated IMA, but not in SV, exogenous L-arginine evoked significant vasodilation (20%). We conclude that VSM of the human IMA possesses an L-arginine/NO pathway inducible by LPS. In SV, LPS or IL-1 beta treatment inhibits contraction by an unidentified system that is not dependent on NO synthase or on guanylate cyclase activities.
authors.affiliation: University Department of Medicine and Therapeutics, Gardiner Institute, Department of Cardiac Surgery, Western Infirmary, Glasgow, United Kingdom.
authors.forename: N
authors.initials: N
authors.lastname: Thorin-Trescases
authors.forename: C A
authors.initials: CA
authors.lastname: Hamilton
authors.forename: J L
authors.initials: JL
authors.lastname: Reid
authors.forename: K L
authors.initials: KL
authors.lastname: McPherson
authors.forename: E
authors.initials: E
authors.lastname: Jardine
authors.forename: G
authors.initials: G
authors.lastname: Berg
authors.forename: D
authors.initials: D
authors.lastname: Bohr
authors.forename: A F
authors.initials: AF
authors.lastname: Dominiczak
mesh_terms: D000368:Aged; D001120:Arginine / Q000031:analogs & derivatives / Q000494:pharmacology / Q000502:physiology*; D004730:Endothelium, Vascular / Q000502:physiology; D005260:Female; D006801:Humans; D066298:In Vitro Techniques; D007213:Indomethacin / Q000494:pharmacology; D007375:Interleukin-1 / Q000494:pharmacology; D008070:Lipopolysaccharides / Q000494:pharmacology; D008297:Male; D008323:Mammary Arteries / Q000187:drug effects / Q000502:physiology*; D008875:Middle Aged; D009131:Muscle, Smooth, Vascular / Q000187:drug effects / Q000502:physiology; D019331:NG-Nitroarginine Methyl Ester; D009569:Nitric Oxide / Q000037:antagonists & inhibitors / Q000502:physiology*; D010656:Phenylephrine / Q000494:pharmacology; D011189:Potassium Chloride / Q000494:pharmacology; D012501:Saphenous Vein / Q000187:drug effects / Q000502:physiology*; D014661:Vasoconstriction / Q000187:drug effects / Q000502:physiology; D019323:omega-N-Methylarginine
chemical_list: D007375:Interleukin-1; D008070:Lipopolysaccharides; D010656:Phenylephrine; D019323:omega-N-Methylarginine; D009569:Nitric Oxide; D011189:Potassium Chloride; D001120:Arginine; D019331:NG-Nitroarginine Methyl Ester; D007213:Indomethacin