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目的 研究大鼠肺内动脉平滑肌细胞钾电流。方法 用急性酶解分离法得到单个大鼠肺内动脉平滑肌细胞 ,采用膜片钳全细胞记录方式研究钾通道特性。结果 将平滑肌细胞钳制在 - 70mV ,给予 - 70～ 5 0mV的斜坡刺激 ,时间为 6 0 0ms。可引出一随电压逐渐增大的电流 ,在 + 5 0mV时其值为 35 9± 31pA。细胞内用CsCl取代KCl后 ,该电流几乎完全消失 ;细胞外用无钙台氏液灌流 ,电极内液用高浓度的EGTA时 ,电流可被抑制 5 0 %± 1% ;细胞外给予特异性钙激活钾通道阻断剂TEA和延迟整流钾通道阻断剂 4 AP均可使该电流明显下降。结论 大鼠肺内动脉平滑肌细胞的钾电流主要由钙激活钾电流和延迟整流钾电流组成
Objective To study the potassium currents in rat pulmonary artery smooth muscle cells. Methods Pulmonary artery smooth muscle cells of a single rat were isolated by acute enzymatic dissociation method and the characteristics of potassium channels were studied by patch clamp whole cell recording. Results The smooth muscle cells were clamped to -70mV and stimulated with slope of -70 ~ 50mV for 6 0 ms. This leads to a current that increases with voltage, which is 35 9 ± 31 pA at +50 mV. The intracellular use of CsCl instead of KCl, the current almost completely disappeared; extracellular calcium-free Tryphostachysis perfusion, the electrode solution with high concentrations of EGTA, the current can be inhibited by 50% ± 1% extracellular administration of specific calcium Activation of potassium channel blockers TEA and delayed rectifier potassium channel blockers 4 AP can make the current significantly decreased. Conclusions The potassium currents in rat pulmonary arterial smooth muscle cells are mainly composed of calcium-activated potassium current and delayed rectifier potassium current