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在由股动脉放血制备的失血性休克大鼠模型急性分离的肠系膜动脉平滑肌细胞上 ,利用膜片箝单通道记录技术观察了血管平滑肌依钙K+通道 (BKCa)的活动。发现在对去甲肾上腺素 (NE)反应性增高的休克代偿期 ,BKCa的开放概率 (Po)和单位电导都显著较正常动物的低 ,Po 的改变主要是由通道的慢关闭时间常数 (τcs)增大引起关闭时间延长所致 ;而处于对NE反应性降低的休克失代偿期 ,BKCa的Po 和单位电导都高于正常动物 ,Po的变化也主要是τcs减小所致。
Vascular smooth muscle activity by calcium channel K + (BKCa) was observed using patch-clamp single-channel recording technique on acutely isolated mesenteric artery smooth muscle cells from a hemorrhagic shock rat model prepared by perfusion of the femoral artery. It was found that the open probability (Po) and unit conductance of BKCa were significantly lower than those of normal animals at shock compensatory phase with increased norepinephrine (NE). The change of Po was mainly caused by the slow turn-off time constant of channel τcs), which lead to the prolongation of the closure time; while in the period of decompensation of shock with reduced reactivity to NE, the Po and unit conductance of BKCa were higher than that of normal animals, and the change of Po was also mainly caused by the decrease of τcs.