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中国应用生理学杂志 ›› 2018, Vol. 34 ›› Issue (5): 470-475.doi: 10.12047/j.cjap.5675.2018.107

• 研究论文 • 上一篇    下一篇

褪黑素激活大鼠大脑中动脉BKCa通道的受体依赖和非受体依赖途径

陈渝, 徐召霞, 张慧荣, 吴迎, 石丽君   

  1. 北京体育大学运动与体质健康教育部重点实验室, 北京 100084
  • 收稿日期:2018-01-09 修回日期:2018-09-25 出版日期:2018-09-28 发布日期:2019-02-21
  • 通讯作者: 石丽君,Tel:010-62989582;E-mail:l_j_shi72@163.com E-mail:l_j_shi72@163.com
  • 基金资助:
    国家自然科学基金(31771312,31371201);北京市自然科学基金(5172023)

The receptor-dependent and non-receptor-dependent mechanism of melatonin activated BKCa channels in middle cerebral artery myocyte

CHEN Yu, XU Zhao-xia, ZHANG Hui-rong, WU Ying, SHI Li-jun   

  1. Key Laboratory of Physical Fitness and Exercise, Ministry of Education, Beijing Sport University, Beijing 100084, China
  • Received:2018-01-09 Revised:2018-09-25 Online:2018-09-28 Published:2019-02-21
  • Supported by:
    国家自然科学基金(31771312,31371201);北京市自然科学基金(5172023)

摘要: 目的:研究褪黑素通过大电导Ca2+激活K+(BKCa)通道介导大脑中动脉张力变化的作用机制。方法:8周龄雄性Wistar大鼠,麻醉后取大脑中动脉,酶消化法急性分离脑中动脉平滑肌细胞,采用膜片钳技术全细胞记录模式检测细胞外液加入褪黑素前后BKCa通道和电压门控钾(KV)通道的电流密度,褪黑素受体抑制剂2-苯基-N-乙酰色胺(luzindole)孵育后,全细胞记录模式记录加入褪黑素后BKCa通道电流幅值和贴附式单通道记录模式记录加入褪黑素后BKCa通道Po值,内面向外记录模式检测加入褪黑素后BKCa通道电导(G),开放概率(Po),平均开放时间(To)和关闭时间(Tc)。结果:①褪黑素(100 μmol/L)显著增加全细胞BKCa通道电流密度,但对KV通道电流密度无显著影响;②luzindole (1 μmol/L)显著抑制褪黑素引起的BKCa通道电流密度增加;③贴附式单通道记录模式下,褪黑素(100 μmol/L)增加BKCa单通道Po值,luzindole (1 μmol/L)显著抑制褪黑素引起的Po增加;④内面向外单通道记录模式下,褪黑素(1 μmol/L,100 μmol/L)缩短BKCa单通道的To和Tc值,且Tc较To显著缩短;结论:褪黑素通过受体依赖和非受体依赖途径激活BKCa通道,介导大脑中动脉血管舒张。

关键词: 褪黑素, BKCa通道, 大脑中动脉, 褪黑素受体, 大鼠

Abstract: Objective: To investigate the mechanisms through which myocyte large-conductance Ca2+-activated K+ (BKCa) channels mediate the vasodilation effects of melatonin on cerebral arteries (CAs). Methods: Middle cerebral arteries (MCA) were obtained from 8-week-old male Wistar rats after anaesthetized. Middle cerebral arterial smooth muscle cells were enzymatically isolated. Whole cell recording mode of patch clamp technique was used to measure the current density of BKCa channel and voltage-gated potassium (KV) channel before and after adding melatonin. Currents density of melatonin on BKCa channels with melatonin receptor inhibitor 2-phenyl-N-acetyl (luzindole) was recorded using whole cell recording mode and open probability (Po) was recorded using single-channel attached recording mode. The conductance (G) and average open time (To) and off time (Tc) of the BKCa channel were detected before and after the addition of melatonin in the internal-outward mode. Results: ① Melatonin markedly increased the whole-cell BKCa channel current density but not the voltage-gated potassium (KV) channel current density. ② Luzindole (1 μmol/L) greatly suppressed melatonin-induced increase of BKCa channel current density. ③ The Po of BKCa channel was significantly increased by melatonin (100 μmol/L) under cell attached recording mode, which was markedly inhibited by luzindole (1 μmol/L). ④ In inside-outside recording mode, melatonin (1 μmol/L, 100 μmol/L) reduced both To and Tc of BKCa channel, and Tc was reduced much more than To. Conclusion: Melatonin mediates vasodilation of MCA through the activation of BKCa channels via both melatonin receptor dependent and independent mode.

Key words: melatonin, BKCa channel, middle cerebral artery, melatonin receptor, rats

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