title: Superoxide constricts rat pulmonary arteries via Rho-kinase-mediated Ca(2+) sensitization.
abstract: Reactive oxygen species play a key role in vascular disease, pulmonary hypertension, and hypoxic pulmonary vasoconstriction. We investigated contractile responses, intracellular Ca(2+) ([Ca(2+)](i)), Rho-kinase translocation, and phosphorylation of the regulatory subunit of myosin phosphatase (MYPT-1) and of myosin light chain (MLC(20)) in response to LY83583, a generator of superoxide anion, in small intrapulmonary arteries (IPA) of rat. LY83583 caused concentration-dependent constrictions in IPA and greatly enhanced submaximal PGF(2alpha)-mediated preconstriction. In small femoral or mesenteric arteries of rat, LY83583 alone was without effect, but it relaxed a PGF(2)alpha-mediated preconstriction. Constrictions in IPA were inhibited by superoxide dismutase and tempol, but not catalase, and were endothelium and guanylate cyclase independent. Constrictions were also inhibited by the Rho-kinase inhibitor Y27632 and the Src-family kinase inhibitor SU6656. LY83583 did not raise [Ca(2+)](i), but caused a Y27632-sensitive constriction in alpha-toxin-permeabilized IPA. LY83583 triggered translocation of Rho-kinase from the nucleus to the cytosol in pulmonary artery smooth muscle cells and enhanced phosphorylation of MYPT-1 at Thr-855 and of MLC(20) at Ser-19 in IPA. This enhancement was inhibited by superoxide dismutase and abolished by Y27632. Hydrogen peroxide did not activate Rho-kinase. We conclude that in rat small pulmonary artery, superoxide triggers Rho-kinase-mediated Ca(2+) sensitization and vasoconstriction independent of hydrogen peroxide.
authors.affiliation: King's College London, UK. greg.knock@kcl.ac.uk
authors.forename: Greg A
authors.initials: GA
authors.lastname: Knock
authors.forename: Vladimir A
authors.initials: VA
authors.lastname: Snetkov
authors.forename: Yasin
authors.initials: Y
authors.lastname: Shaifta
authors.forename: Michelle
authors.initials: M
authors.lastname: Connolly
authors.forename: Svetlana
authors.initials: S
authors.lastname: Drndarski
authors.forename: Anthony
authors.initials: A
authors.lastname: Noah
authors.forename: Ghazaleh E
authors.initials: GE
authors.lastname: Pourmahram
authors.forename: Silke
authors.initials: S
authors.lastname: Becker
authors.forename: Philip I
authors.initials: PI
authors.lastname: Aaronson
authors.forename: Jeremy P T
authors.initials: JP
authors.lastname: Ward
mesh_terms: D021581:Active Transport, Cell Nucleus / Q000187:drug effects; D000577:Amides / Q000494:pharmacology; D000634:Aminoquinolines / Q000494:pharmacology; D000818:Animals; D016084:Bronchoconstriction / Q000187:drug effects / Q000502:physiology*; D020013:Calcium Signaling / Q000502:physiology; D006162:Guanylate Cyclase / Q000037:antagonists & inhibitors; D006976:Hypertension, Pulmonary / Q000201:enzymology* / Q000473:pathology / Q000517:prevention & control; D007211:Indoles / Q000494:pharmacology; D008297:Male; D032389:Myocytes, Smooth Muscle / Q000473:pathology / Q000502:physiology*; D018994:Myosin Light Chains / Q000378:metabolism; D010766:Phosphorylation; D054645:Protein Phosphatase 1 / Q000378:metabolism; D011651:Pulmonary Artery / Q000473:pathology; D011725:Pyridines / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar; D013449:Sulfonamides / Q000494:pharmacology; D013481:Superoxides / Q000494:pharmacology*; D054460:rho-Associated Kinases / Q000037:antagonists & inhibitors / Q000502:physiology*; D019061:src-Family Kinases / Q000037:antagonists & inhibitors / Q000502:physiology*
chemical_list: D000577:Amides; D000634:Aminoquinolines; D007211:Indoles; D018994:Myosin Light Chains; D011725:Pyridines; C416927:SU 6656; D013449:Sulfonamides; D013481:Superoxides; C108830:Y 27632; C041715:6-anilino-5,8-quinolinedione; D019061:src-Family Kinases; D054460:rho-Associated Kinases; C499850:Ppp1r12a protein, rat; D054645:Protein Phosphatase 1; D006162:Guanylate Cyclase