Mechanism of dilation to reactive oxygen species in human coronary arterioles.
Mechanism of dilation to reactive oxygen species in human coronary arterioles.
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人冠状动脉中活性氧的扩张机制。
DOI：
10.1152/ajpheart.00458.2003
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发表时间：
2003
期刊：
影响因子：
--
通讯作者：
Gutterman,DavidD
中科院分区：
文献类型：
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作者：
Sato,Atsushi;Sakuma,Ichiro;Gutterman,DavidD
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 (10–4M) + 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 × 10–5M), diethyldithiocarbamate trihydrate (DDC, 10–2M), and deferoxamine (DFX, 10–3M) 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 (\batchmode \documentclass[fleqn,10pt,legalpaper]{article} \usepackage{amssymb} \usepackage{amsfonts} \usepackage{amsmath} \pagestyle{empty} \begin{document} \(\mathrm{O}_{2}^{-}{\cdot}\) \end{document}) by XA/XO is spontaneously converted to H2O2, which dilates HCA through vascular smooth muscle hyperpolarization. \batchmode \documentclass[fleqn,10pt,legalpaper]{article} \usepackage{amssymb} \usepackage{amsfonts} \usepackage{amsmath} \pagestyle{empty} \begin{document} \(\mathrm{O}_{2}^{-}{\cdot}\) \end{document} is also converted to H2O2likely 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 H2O2may elicit vasodilation by different mechanisms.
