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Short-term simulated weightlessness enhances response of L-type calcium channel to angiotensin Ⅱ in cerebral vascular smooth muscle cells in rats
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- Author:
- No author available
- Journal Title:
- ACTA PHYSIOLOGICA SINICA
- Issue:
- 1
- DOI:
- No doi available
- Key Word:
- 微重力;血管平滑肌细胞;Ca2+通道;血管紧张素Ⅱ
Abstract： 已有研究表明模拟失重可引起大鼠脑动脉发生区域特异性变化,其中Ca2+通道和肾素-血管紧张素系统(renin-angio-tensin system,RAS)可能发挥着重要的作用.本研究旨在探讨血管紧张素Ⅱ(angiotensin Ⅱ,Ang Ⅱ)对短期模拟失重大鼠脑基底动脉血管平滑肌细胞(vascular smooth muscle cells,VSMCs)L-型Ca2+通道(L-type calcium channel,CaL)功能的影响.模拟失重(尾部悬吊)3 d后,用木瓜蛋白酶法分离大鼠脑基底动脉VSMCs.采用全细胞膜片钳技术,以Ba2+作为载流子,测定CaL电流密度,然后观察Ang Ⅱ对该电流的影响.结果显示,模拟失重3 d对大鼠脑基底动脉VSMCs的膜电容和接入电阻无明显影响,但可致VSMCs的CaL电流密度显著增加.不过,模拟失重对CaL的电压激活特性和稳态激活曲线亦无明显影响.对照组和模拟失重组大鼠脑基底动脉VSMCs的CaL电流密度在给予Ang Ⅱ处理后均显著增加,且模拟失重组的增加幅度显著大于对照组.以上结果提示,3 d短期模拟失重即可引起大鼠脑动脉VSMCs的CaL发生适应性改变,且可导致其对Ang Ⅱ的反应性增强,表明Ang Ⅱ可能在脑动脉失重适应性改变中起着一定的作用.
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