title: Oxidative stress impairs vasorelaxation induced by the soluble guanylyl cyclase activator BAY 41-2272 in spontaneously hypertensive rats.
abstract: BACKGROUND
  BAY 41-2272 (5-cyclopropyl-2-[1-(2-fluoro-benzyl)-1H-pyrazolo[3,4-b]pyridin-3-yl]-pyrimidin-4-ylamine) relaxes mesenteric arteries (MA) in a synergistic fashion with nitric oxide (NO). We hypothesized that the relaxation to BAY 41-2272 is decreased in spontaneously hypertensive rats (SHR) because of the reduced NO bioavailability in this strain and that relaxation would be improved by inhibiting the oxidative stress. We aimed to evaluate the influence of oxidative stress in BAY 41-2272-induced vasorelaxation in isolated MA from SHR.
  
  
  METHODS
  MA function was evaluated by concentration-response curves to BAY 41-2272. We measured protein expression of endothelial NO synthase (eNOS), soluble guanylyl cyclase (sGC) and human-antigen R (HuR) (sGC mRNA-stabilizing protein), sGC activity and plasma levels of superoxide dismutase (SOD), and total antioxidant status (TAS).
  
  
  RESULTS
  Cyclic guanosine monophosphate (cGMP)-dependent and -independent relaxation induced by BAY 41-2272 (0.0001-1 micromol/l) was impaired in SHR compared with Wistar-Kyoto (WKY). We observed reduced expression of eNOS, sGC and HuR, and decreased sGC activity in SHR. Plasma levels of SOD and TAS were also diminished in SHR. Incubation with SOD or indomethacin increased relaxation to BAY 41-2272 in SHR. Furthermore, acetylcholine (ACh)-induced relaxation was increased in the presence of BAY 41-2272 or SOD, apocynin, or indomethacin.
  
  
  CONCLUSIONS
  Augmented oxidative stress in SHR impaired cGMP-dependent and -independent relaxation induced by BAY 41-2272, by decreasing NO bioavailability and sGC expression and by increasing contractile activity. Inhibiton of oxidative stress improved the relaxation of BAY 41-2272 in SHR. BAY 41-2272 might be an alternative therapeutic tool for hypertension if administrated with antioxidant compounds.
authors.affiliation: Department of Physical Education, Institute of Biosciences, São Paulo State University, UNESP, São Paulo, Brazil. fernanda.bmp@gmail.com
authors.forename: Fernanda B M
authors.initials: FB
authors.lastname: Priviero
authors.forename: Saiprasad M
authors.initials: SM
authors.lastname: Zemse
authors.forename: Cleber E
authors.initials: CE
authors.lastname: Teixeira
authors.forename: R Clinton
authors.initials: RC
authors.lastname: Webb
mesh_terms: D000098:Acetophenones / Q000494:pharmacology; D000109:Acetylcholine / Q000494:pharmacology; D000818:Animals; D000975:Antioxidants / Q000378:metabolism; D019086:Bridged Bicyclo Compounds, Heterocyclic; D006152:Cyclic GMP / Q000502:physiology; D004730:Endothelium, Vascular / Q000502:physiology; D004789:Enzyme Activation; D005231:Fatty Acids, Unsaturated; D006162:Guanylate Cyclase / Q000037:antagonists & inhibitors / Q000378:metabolism*; D006834:Hydrazines / Q000494:pharmacology; D052250:Nitric Oxide Synthase Type III / Q000378:metabolism; D009599:Nitroprusside / Q000494:pharmacology; D018384:Oxidative Stress / Q000187:drug effects; D011720:Pyrazoles / Q000494:pharmacology*; D011725:Pyridines / Q000494:pharmacology*; D051381:Rats; D011918:Rats, Inbred SHR; D018160:Receptors, Cytoplasmic and Nuclear / Q000037:antagonists & inhibitors / Q000378:metabolism*; D000071756:Soluble Guanylyl Cyclase; D013482:Superoxide Dismutase / Q000378:metabolism; D014664:Vasodilation / Q000187:drug effects*; D014665:Vasodilator Agents / Q000494:pharmacology
chemical_list: C423582:3-(4-Amino-5-cyclopropylpyrimidine-2-yl)-1-(2-fluorobenzyl)-1H-pyrazolo(3,4-b)pyridine; D000098:Acetophenones; D000975:Antioxidants; D019086:Bridged Bicyclo Compounds, Heterocyclic; D005231:Fatty Acids, Unsaturated; D006834:Hydrazines; D011720:Pyrazoles; D011725:Pyridines; D018160:Receptors, Cytoplasmic and Nuclear; D014665:Vasodilator Agents; D009599:Nitroprusside; C045749:SQ 29548; C056165:acetovanillone; D052250:Nitric Oxide Synthase Type III; C496316:Nos3 protein, rat; D013482:Superoxide Dismutase; D006162:Guanylate Cyclase; D000071756:Soluble Guanylyl Cyclase; D006152:Cyclic GMP; D000109:Acetylcholine