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铁对血管收缩活动的影响及其机制

况炜, 陈莹莹, 沈岳良, 夏强

浙江大学医学院生理学教研室，杭州310031；宁波卫生高等职业技术学院，宁波315000

摘要

动脉粥样硬化的发生和铁引起的氧化应激密切相关。铁对血管的直接效应及其对血管收缩功能的影响尚不明确。本文采用血管环灌流装置，观察铁对离体SD大鼠去内皮胸主动脉环的直接效应，及对去内皮主动脉环KC1和苯肾上腺素(P助引发的收缩效应的影响。结果显示:(1)100 umol/L构椽酸铁(FAC)引起大鼠血管环发生相位性收缩，最大收缩幅度可达KCl诱发的最大收缩的24.02士2.37。当「"2 +]。增加1倍时，铁所致的血管环收缩幅
度明显增加(P<0.01) o阻断L-型钙通道后，铁所致的血管环收缩幅度明显降低(P <0.01)。在无钙液中，用佛波酷收缩血管环，待收缩稳定后给予FAC，此时收缩幅度增加49.18士3.75 % o (2)铁孵育30 min后，KCl引起血管环收缩的幅度显著降低(P<0.01。铁孵育可使PE引起的收缩量一效曲线右移(P<0.05) o (3)二甲基亚矾、过氧化氢酶和谷肤甘肤可明显降低铁对PE血管收缩反应的抑制作用(P<0.05)。从这些结果可得到以下结论:铁可引起胸主动脉发生相位性收缩，其机制可能与L型钙通道短暂开放导致钙离子内流，及平滑肌对钙的敏感性增加有关;较长时间与铁孵育后，可对血管收缩功能产生损伤，氧自由基的生成增加和细胞内GS H的水平降低可能参与铁对收缩功能的损害。

关键词： 铁; 胸主动脉; 收缩; L型钙通道; 活性氧

Effect of iron on vasoconstriction in the isolated rat aorta

KUANG Wei, Chen Yingying, SHEN Yue-Liag, Xia Qiang

Department of Physiology, Zhejiang University Medicine, Hangzhou 310031；Department of Physiology of Technical College，Ningbo 315000

Abstract

The present stu勿was to examine the effect of iron on isolated rat aortic rings，and to elucidate the underlying mechanism .The thoracic aortic rings without endothelium of male Sprague- Dawley rats were mounted on a bath system .Isometric contractions of aortic rings were measured. The results obtained are as follows.(1)Ferric ammonium citrate(FAQ(100 p mol/ L) caused a phasic response with an initial transient contraction followed by a relaxation in thoracic aortic ring.The maximal contractile amplitude was 24. 02士2.37‘the maximal contraction induced by K the duration of phasic contraction lasted for about 20 min.(2) In high Ca~(2+)Krebs- Henseleit(K H) solution(twice of the normal concentration)，the contractile amplitude induced FAC
was enhanced.After the aortic rings were incubated with nifedipine for 15 min to block the L type Ca~(2+)channel，the iron-induced contraction was attenuated.(3) In Ca~(2+)--free K H solution，addition of FAC caused a strong
and sustained contraction in the presence of PDBi.(4) Pretreatment of FAC for 30 min decreased the KCI-induced contraction and also caused a significant reduction in the contractile response to phenylephrine(PE).Pretreatment of the arteries with DMSO，catalase or glutathione before FAC exposure prevented the decrease in contraction responses to PE(P<0.05).It is therefore concluded that iron causes phasic contraction of vascular smooth muscle，in which both extracellular Ca~(2+)entry through L -type Ca~(2+)channel and increase in Ca~(2+)sensitivity of smooth muscle cells are involved .Exposure to iron causes inhibitory effects on K〔一or PE induced contractions in isolated thoracic arteries.Reactive oxygen species and glutathione may be involved in iron-induced contraction dysfunction.
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Key words: iron;thoracic aorta;vasoconstriction;L type Ca~(2+)channel;reactive oxygen species

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引用本文：

况炜, 陈莹莹, 沈岳良, 夏强. 铁对血管收缩活动的影响及其机制[J]. 生理学报 2003; 55 (3): .

KUANG Wei, Chen Yingying, SHEN Yue-Liag, Xia Qiang. Effect of iron on vasoconstriction in the isolated rat aorta. Acta Physiol Sin 2003; 55 (3): (in Chinese with English abstract).