四周模拟失重大鼠后身动脉平滑肌细胞钾电流的改变

Changes in potassium currents of vascular smooth muscle cells isolated from hindquarter arteries of rats after 4 weeks simulated weightlessness

本文采用全细胞膜片钳方法观察 4周尾部悬吊大鼠 (tail suspendedrats,SUS)隐动脉及肠系膜前动脉第 2～ 6级动脉分支血管平滑肌细胞 (vascularsmoothmusclecells,VSMCs)钾电流密度的变化。结果表明 :SUS大鼠后身动脉VSMCs的静息电位 (RP)较对照大鼠 (CON)后身动脉VSMCs的RP更负。SUS组隐动脉和肠系膜小动脉VSMCs的全细胞钾电流密度较CON组显著增加。其中 ,SUS组的隐动脉和肠系膜小动脉VSMCs的大电导钙激活钾离子通道 (BKCa)和电压激活钾离子通道 (KV)电流密度较CON组的BKCa和KV 电流密度均显著增加。以上结果提示 。

The changes in potassium currents of vascular smooth muscle cells (VSMCs) isolated from saphenous arteries and the 2nd～6th order branches of the mesenteric arteries of 4-week tail-suspended rats (SUS) were examined using whole cell patch clamp technique.The resting potential (RP) of the VSMCs from SUS group was more negative compared with that of the control group (CON).The whole cell potassium current densities of VSMCs isolated from the saphenous arteries and small mesenteric arteries in SUS group were significantly larger than those of the CON group.The BK Ca and K V current densities of VSMCs from saphenous arteries and small mesenteric arteries from SUS group were also significantly larger than those from the CON group.It is speculated that the hyperpolarization of VSMCs and decreased calcium influx through voltage-dependent calcium channels might be one of the electrophysiological mechanisms involved in the depressed vasoreactivity of hindquarter arteries induced by simulated weightlessness.