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Changes in voltage-dependent calcium channel currents of vascular smooth muscle cells isolated from small mesenteric arteries of simulated weightless rats
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- Author:
- No author available
- Journal Title:
- ACTA PHYSIOLOGICA SINICA
- Issue:
- 1
- DOI:
- 10.3321/j.issn:0371-0874.2005.01.005
- Key Word:
- 微重力;飞行后心血管失调;血管平滑肌细胞;钙离子通道;阻力性小动脉血管
Abstract： 本工作旨在探讨短、中期模拟失重下大鼠肠系膜小动脉血管平滑肌细胞(vascular smooth muscle cells,VSMCs)电压依赖性钙离子通道(voltage-dependent calcium channels,VDC)功能的改变.以尾部悬吊大鼠模型模拟失重对不同部位血管的影响.采用全细胞膜片钳实验技术,以Ba2+作为载流子,测定1周及4周模拟失重大鼠肠系膜小动脉VSMCs的VDC电流密度、稳态激活与失活曲线及有关参数,并与对照组结果进行比较.研究表明,本实验所记录到的内向电流主要为钡离子通过长时程VDC(L-VDC)所形成的电流.与对照组相比,1周模拟失重大鼠肠系膜小动脉VSMCs的L-VDC电流密度仅呈降低趋势;但4周模拟失重大鼠肠系膜小动脉VSMCs的L-VDC电流密度则已显著降低.此外,与对照组相比,1、4周模拟失重大鼠肠系膜小动脉VSMCs的膜电容、翻转电位与L-VDC的一些动力学特征值,如通道的开放与关闭速率,通道电流稳态激活与失活曲线及其特征拟合参数V0.5与k的值,均未见有显著改变.结果提示:模拟失重下后身小动脉VSMCs的VDC功能降低可能是模拟失重引起大鼠后身动脉收缩反应性降低及适应性萎缩变化的电生理机制之一.
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