急性缺氧对大鼠肺动脉平滑肌细胞电压门控钾通道电流的影响

目的：研究急性缺氧对大鼠肺动脉平滑肌细胞电压门控钾通道（Kv）电流的影响。方法：雄性SD大鼠20只随机分为常氧对照组和急性缺氧组（各10只）。急性缺氧组大鼠在低氧仓中缺氧停留8h后进行实验。应用全细胞膜片钳技术记录肺动脉平滑肌细胞电压门控钾通道电流（Ik）。结果：急性缺氧显著降低大鼠肺动脉平滑肌细胞的Ik密度。在大鼠肺动脉平滑肌细胞静息膜电位-60mV至-10mV时，急性缺氧降低大鼠肺动脉平滑肌细胞的IK密度不明显（P〉0．05）。在0mV时，大鼠肺动脉平滑肌细胞的峰值Ik密度显著下降[从（38．1±5．2）pA／pF→（9．82±2．1）pA／pF，P〈0．05）]，此后随着细胞静息膜电位的增加，平滑肌细胞的Ik密度下降幅度逐渐增加（P〈0．05）；从＋30mV至＋60mV时，平滑肌细胞的Ik密度下降幅度更大（P〈0．01）。在＋60mV时，IK密度峰值从（135．4±16．5）pA／pF降到（73．1±10．6）pA／pF，降幅达（46．8±3．3）％。结论：急性缺氧可降低肺动脉平滑肌细胞Kv电流，导致肺血管缺氧性收缩。

Influence of acute hypoxia on current of voltage-gated potassium channel in pulmonary artery smooth muscle cells of rats

Objective： To study influence of acute hypoxia on the current of voltage-gated potassium channel （Ik） in pulmonary artery smooth muscle cells （PASMC） of rats. Methods： A total of 20 male SD rats were randomly and e-qually divided into normoxic control group and acute hypoxia group. The rats in acute hypoxia group were kept in hypoxic chamber for 8 h before experiment. Whole cell patch-clamp technique was used to record Ik in PASMC. Re-ults： Acute hypoxia significantly decreased the Ik density in PASMC of rats. During -60mV to -10mV of resting membrane potential（RMP）, acute hypoxia did not significantly decrease peak Ik density in PASMC of rats, P〉 0.05; At 0 mV, acute hypoxia significantly decreased the peak Ik density in PASMC [from（38.1 ± 5.2） pA / pF decreased to（9.82 ± 2.1） pA / pF , P〈0. 051, then along with RMP increase in PASMC, the decreasing amplitude of peak Ik density in PASMC gradually increased（P〈0.05） ; From ＋ 30 mV to ＋ 60 mV, the decreasing amplitude of peak IK density in PASMC further significantly increased（P（0.01）; At ＋ 60 mV the peak Ik density decreased from（38.1 ± 5.2） pA / pF to（9.82 ± 2.1） pA / pF , and the decreasing amplitude reached （46.8±3.3）%. Con- clusion：Acute hypoxia can decrease Kv current in PASMC of rats, leading to hypoxic pulmonary vasoconstriction.