Document Detail

Mechanism of dilation to reactive oxygen species in human coronary arterioles.
MedLine Citation:
PMID:  14613909     Owner:  NLM     Status:  MEDLINE    
We tested whether reactive oxygen species (ROS) generated from treatment with xanthine (XA) and xanthine oxidase (XO) alter vascular tone of human coronary arterioles (HCA). Fresh human coronary arterioles (HCA) from right atrial appendages were cannulated for video microscopy. ROS generated by XA (10(-4) M) + XO (10 mU/ml) dilated HCA (99 +/- 1%, 20 min after application of XA/XO). This dilation was not affected by denudation or superoxide dismutase (150 U/ml). Catalase (500 U/ml or 5,000 U/ml) attenuated the dilation early on, but a significant latent vasodilation appeared after 5 min peaking at 20 min (51 +/- 1%, 20 min after application of XA/XO + 500 U/ml catalase, P < 0.01 vs. control). KCl (40 mM) reduced the early and sustained vasodilation to XA/XO in the absence of catalase but 1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one (ODQ, 5 x 10(-5) M), diethyldithiocarbamate trihydrate (DDC, 10(-2) M), and deferoxamine (DFX, 10(-3) M) had no effect. In contrast, the catalase-resistant vasodilation was significantly attenuated by DDC, ODQ, and DFX as well as polyethylene-glycolated catalase (5,000 U/ml), but KCl had no effect. Confocal microscopy revealed that even in the presence of catalase, 2',7'-dichlorodihydrofluoresein diacetate fluorescence was observed in the vascular smooth muscle, but this was abolished by DDC. These data indicate that the exogenously generated superoxide anion (O2-*) by XA/XO is spontaneously converted to H2O2, which dilates HCA through vascular smooth muscle hyperpolarization. O2-* is also converted to H2O2 likely by superoxide dismustase within vascular cells and dilates HCA through a different pathway involving the activation of guanylate cyclase. These findings suggest that exogenously and endogenously produced H2O2 may elicit vasodilation by different mechanisms.
Atsushi Sato; Ichiro Sakuma; David D Gutterman
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Publication Detail:
Type:  In Vitro; Journal Article; Research Support, Non-U.S. Gov't; Research Support, U.S. Gov't, Non-P.H.S.; Research Support, U.S. Gov't, P.H.S.    
Journal Detail:
Title:  American journal of physiology. Heart and circulatory physiology     Volume:  285     ISSN:  0363-6135     ISO Abbreviation:  Am. J. Physiol. Heart Circ. Physiol.     Publication Date:  2003 Dec 
Date Detail:
Created Date:  2003-11-17     Completed Date:  2003-12-24     Revised Date:  2007-11-15    
Medline Journal Info:
Nlm Unique ID:  100901228     Medline TA:  Am J Physiol Heart Circ Physiol     Country:  United States    
Other Details:
Languages:  eng     Pagination:  H2345-54     Citation Subset:  IM    
Department of Internal Medicine, Cardiovascular Center, and Veterans Affair Medical Center, Medical College of Wisconsin, 8701 Watertown Plank Rd., Milwaukee, WI 53226, USA.
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MeSH Terms
Arterioles / physiology
Coronary Vessels / physiology*
Hydrogen Peroxide / metabolism
Reactive Oxygen Species / metabolism*
Signal Transduction / drug effects,  physiology
Superoxide Dismutase / metabolism
Superoxides / metabolism
Vasodilation / drug effects,  physiology*
Xanthine / pharmacology
Xanthine Oxidase / pharmacology
Grant Support
Reg. No./Substance:
0/Reactive Oxygen Species; 11062-77-4/Superoxides; 69-89-6/Xanthine; 7722-84-1/Hydrogen Peroxide; EC Dismutase; EC Oxidase

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