中国组织工程研究

中国组织工程研究 ›› 2012, Vol. 16 ›› Issue (24): 4520-4525.doi: 10.3969/j.issn.1673-8225.2012.24.031

• 组织构建基础实验 basic experiments in tissue construction • 上一篇    下一篇

平滑肌BKCa通道在运动改变大鼠胸主动脉舒缩特性中的作用

石丽君，曾凡星，李珊珊，刘晓东   

  1. 北京体育大学运动生理教研室，北京市 100084
  • 收稿日期:2011-11-08 修回日期:2011-12-12 出版日期:2012-06-10 发布日期:2013-11-05
  • 通讯作者: 石丽君☆，女，1972年生，河北省内丘县人，汉族，2009年北京体育大学毕业，博士，副教授，主要从事运动与心脑血管功能调控的研究。 l_j_shi72@163.com
  • 作者简介:Shi Li-jun☆, Doctor, Associate professor, Department of Exercise Physiology, Beijing Sport University, Beijing 100084, China l_j_shi72@163.com
  • 基金资助:

    国家自然科学基金(31071033)；教育部高等学校博士学科点专项科研基金(20101112120001)；北京市优秀人才培养资助 (2010D009010000001)；留学科技活动项目择优资助(国家人力资源和社会保障部)

Effect of smooth muscle large-conductance Ca2+-activated K+ channel on alteration of the thoracic aortic contractility induced by exercise training

Shi Li-jun, Zeng Fan-xing, Li Shan-shan, Liu Xiao-dong   

  1. Department of Exercise Physiology, Beijing Sport University, Beijing 100084, China
  • Received:2011-11-08 Revised:2011-12-12 Online:2012-06-10 Published:2013-11-05
  • Contact: Shi Li-hua, Doctor, Associate professor, Department of Exercise Physiology, Beijing Sport University, Beijing 100084, China l_j_shi72@163.com
  • About author:石丽君☆，女，1972年生，河北省内丘县人，汉族，2009年北京体育大学毕业，博士，副教授，主要从事运动与心脑血管功能调控的研究。 l_j_shi72@163.com

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摘要：

背景：大电导钙激活钾通道(BKCa)是调节细胞兴奋性和血管张力的重要离子通道，有关大动脉平滑肌BKCa通道的作用机制鲜有报道。
目的：观察有氧运动对大鼠胸主动脉舒缩特性的影响，并探讨平滑肌BKCa通道在其中的作用。
方法：将20只Wistar大鼠随机分为安静对照组和有氧运动组，运动组进行12周跑台运动，坡度0°, 20 m/min, 60 min/d, 5 d/周。之后每组5只大鼠行股动静脉插管术。恢复1 d后，于在体、清醒状态下进行心血管功能监测。另各组5只大鼠，取胸主动脉制备去内皮血管环，进行体外血管收缩特性检测。
结果与结论：①有氧运动后静脉注射去甲肾上腺素引起的升压反应幅度下降。②静脉注射BKCa通道阻断剂Iberiotoxin可诱发升压反应，且运动组更显著。③ 120 mmol/L KCl在两组胸主动脉血管环均可诱发收缩，最大张力差异无显著性意义。④去甲肾上腺素(10-9~10-5 mol/L)诱发的血管收缩呈浓度依赖性，但运动组的最大张力显著低于安静组。⑤Iberiotoxin (3×10-8 mol/L)预处理血管后，可增强去甲肾上腺素(10-5 mol/L)诱发的张力增加，且运动组增加幅度显著大于安静组。⑥BKCa通道开放剂NS1619 (10-10~10-6 mol/L)可引起去甲肾上腺素诱发的血管收缩张力下降，且运动组对其敏感性(pD2)增加。提示，有氧运动可诱导大鼠心血管反应性和胸主动脉舒缩特性改变，其中平滑肌BKCa通道起着重要作用。

关键词: 大电导钙激活钾通道, 运动, 胸主动脉, 平滑肌, 去甲肾上腺素

Abstract:

BACKGROUND: Large-conductance Ca2+-activated K+ (BKCa) channels play a critical role in regulating the cellular excitability and vascular tone. The reports about the mechanisms of the smooth muscle BKCa channels on the conduit arteries are rare.
OBJECTIVE: To investigate the effects of aerobic exercise on the rat thoracic aortic contractility, and to explore the possible BKCa channel mechanisms underlying these effects.
METHODS: Twenty male Wistar rats were randomly divided into sedentary group and aerobic exercise group. Rats in the aerobic exercise group were preformed with 12 week-treadmill exercise, 0° slope, 20 m/min, 60 min/d, 5 d/wk. After 12 weeks, some animals (n=5 in each group) underwent femoral arterial and venous cannulation. Following 1 day recovery, the cardiovascular responses were monitored in vivo without anesthesia. For the rest animals (n=5 in each group), the thoracic aorta was carefully dissected free, cut into rings, and the endothelial cell lining was removed. The vessel contractility was examined in vitro.
RESULTS AND CONCOUSION: ①The pressor responses induced by intravenous injection of norepinephrine were attenuated in the aerobic exercise group. ②Intravenous injection of iberiotoxin, a selective BKCa channel blocker, caused a pressor response, which was more prominent in aerobic exercise group. ③120 mmol/L KCl elicited a significantly increase of vascular tone in both groups, and there was no significant differences of the maximal tension between two groups. ④Norepinephrine (10-9-10-5 mol/L) induced a concentration-dependent contraction of thoracic aorta in both groups, while the maximal tension in exercise group was significant less than that in the sedentary group. ⑤Iberiotoxin (3×10-8 mol/L) pretreatment could enhance the NE-induced tension increase, which was more significant in exercise training group. ⑥BKCa channel opener NS1619 (10-10-10-6 mol/L) could cause a decrease of norepinephrine-induced vascular contraction, and the sensitivity of tissue to NS619 (pD2) was higher in exercise group than that in the sedentary group. These results suggest that aerobic exercise can change the cardiovascular reactivity and vascular contractility, in which the smooth muscle BKCa channels play an important role.

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