目的　研究粉防己碱 (Tet)对大鼠肺动脉平滑肌细胞小电导钙激活钾通道 (SKCa)的作用。方法　内面朝外膜片箝单通道记录法。结果　Tet 7 5 μmol·L-1对电导值为 10pS的SKCa无明显影响 ,15 μmol·L-1可增加SKCa开放的概率 ,改变通道的开放和关闭模式 ,30 μmol·L-1降低通道的开放概率 ,通道开放以短暂簇状为主。结论　Tet对肺动脉平滑肌SKCa的作用与Tet的浓度有关 ,合适浓度下可增加通道的开放 ,K+ 外流增多 ,与Tet降低肺动脉张力有关。 Objective To study the effect of tetrandrine (Tet) on small conductance calcium-activated potassium channel (SKCa) in rat pulmonary artery smooth muscle cells. Methods Internal-facing patch-clamp single-channel recording method. Results Tet 7 5 μmol·L-1 had no significant effect on SKCa with a conductance of 10 pS. 15 μmol·L-1 increased the probability of opening of SKCa and changed the open and close modes of the channel. 30 μmol·L-1 decreased the channel The probability of opening is that the opening of the channel is mainly short-lived. Conclusion The effect of Tet on pulmonary arterial smooth muscle SKCa is related to the concentration of Tet. At the appropriate concentration, Tet can increase the opening of channels and increase the outflow of K+, which is related to the decrease of pulmonary artery tension by Tet.