Document Detail


Superoxide modulates myogenic contractions of mouse afferent arterioles.
MedLine Citation:
PMID:  21859962     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Reactive oxygen species enhance or impair autoregulation. Because superoxide is a vasoconstrictor, we tested the hypothesis that stretch generates superoxide that mediates myogenic responses. Increasing perfusion pressure of mouse isolated perfused renal afferent arterioles from 40 to 80 mm Hg reduced their diameter by 13.3±1.8% (P<0.001) and increased reactive oxygen species (ethidium: dihydroethidium fluorescence) by 9.8±2.3% (P<0.05). Stretch-induced fluorescence was reduced significantly (P<0.05) by incubation with Tempol (3.7±0.8%), pegylated superoxide dismutase (3.2±1.0%), or apocynin (3.5±0.9%) but not by pegylated catalase, L-nitroarginine methylester, or Ca(2+)-free medium, relating it to Ca(2+)-independent vascular superoxide. Compared with vehicle, basal tone and myogenic contractions were reduced significantly (P<0.05) by pegylated superoxide dismutase (5.4±0.8), Tempol (4.1±1.0%), apocynin (1.0±1.3%), and diphenyleneiodinium (3.9±0.9%) but not by pegylated catalase (10.1±1.6%). L-Nitroarginine methylester enhanced basal tone, but neither it (15.8±3.3%) nor endothelial NO synthase knockout (10.2±1.8%) significantly changed myogenic contractions. Tempol had no further effect after superoxide dismutase but remained effective after catalase. H(2)O(2) >50 μmol/L caused contractions but at 25 μmol/L inhibited myogenic responses (7.4±0.8%; P<0.01). In conclusion, increasing the pressure within afferent arterioles led to Ca(2+)-independent increased vascular superoxide production from nicotinamide adenine dinucleotide phosphate oxidase, which enhanced myogenic contractions largely independent of NO, whereas H(2)O(2) impaired pressure-induced contractions but was not implicated in the normal myogenic response.
Authors:
En Yin Lai; Anton Wellstein; William J Welch; Christopher S Wilcox
Publication Detail:
Type:  Journal Article; Research Support, N.I.H., Extramural; Research Support, Non-U.S. Gov't     Date:  2011-08-22
Journal Detail:
Title:  Hypertension     Volume:  58     ISSN:  1524-4563     ISO Abbreviation:  Hypertension     Publication Date:  2011 Oct 
Date Detail:
Created Date:  2011-09-15     Completed Date:  2011-11-08     Revised Date:  2014-09-22    
Medline Journal Info:
Nlm Unique ID:  7906255     Medline TA:  Hypertension     Country:  United States    
Other Details:
Languages:  eng     Pagination:  650-6     Citation Subset:  IM    
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MeSH Terms
Descriptor/Qualifier:
Acetophenones / pharmacology
Animals
Antioxidants / pharmacology
Arterioles / metabolism*
Cyclic N-Oxides / pharmacology
Enzyme Inhibitors / pharmacology
Kidney / blood supply*
Male
Mice
Mice, Inbred C57BL
Mice, Knockout
Models, Animal
Muscle Contraction / drug effects,  physiology*
Muscle, Smooth, Vascular / metabolism*
NG-Nitroarginine Methyl Ester / pharmacology
Nitric Oxide / metabolism
Nitric Oxide Synthase / antagonists & inhibitors,  genetics,  metabolism
Nitric Oxide Synthase Type III / genetics,  metabolism
Reactive Oxygen Species / metabolism
Spin Labels
Superoxide Dismutase / pharmacology
Superoxides / metabolism*
Grant Support
ID/Acronym/Agency:
DK-036079/DK/NIDDK NIH HHS; DK-049870/DK/NIDDK NIH HHS; HL-089583/HL/NHLBI NIH HHS; HL-68686/HL/NHLBI NIH HHS; P01 HL068686/HL/NHLBI NIH HHS; P01 HL068686-10/HL/NHLBI NIH HHS; R01 DK049870/DK/NIDDK NIH HHS; R01 DK049870-18/DK/NIDDK NIH HHS; R01 HL089583/HL/NHLBI NIH HHS; R01 HL089583-04/HL/NHLBI NIH HHS; R37 DK036079/DK/NIDDK NIH HHS; R37 DK036079-26/DK/NIDDK NIH HHS
Chemical
Reg. No./Substance:
0/Acetophenones; 0/Antioxidants; 0/Cyclic N-Oxides; 0/Enzyme Inhibitors; 0/Reactive Oxygen Species; 0/Spin Labels; 11062-77-4/Superoxides; 2226-96-2/tempol; 31C4KY9ESH/Nitric Oxide; B6J7B9UDTR/acetovanillone; EC 1.14.13.39/Nitric Oxide Synthase; EC 1.14.13.39/Nitric Oxide Synthase Type III; EC 1.14.13.39/Nos3 protein, mouse; EC 1.15.1.1/Superoxide Dismutase; V55S2QJN2X/NG-Nitroarginine Methyl Ester
Comments/Corrections

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