电压依赖性钾通道与Miconazole在低氧性肺血管收缩中的作用

目的观察大鼠肺动脉平滑肌细胞(PaSMCs)膜上电压依赖性钾通道(Kv)与细胞色素P450氧化酶抑制剂Miconazole在低氧性肺血管收缩中的作用。方法采用急性酶分离法分离出大鼠肺动脉平滑肌细胞(PaSMCs),利用全细胞膜片钳技术记录PaSMCs的Kv通道的电流特性;用低氧液体灌流PaSMCs造成急性低氧模型,记录低氧作用前后Kv通道的电流变化;用不同浓度的Miconazole作用于PaSMCs,记录加药前后的电流变化。结果低氧液体灌流以及不同浓度的Miconazole对Kv均有明显的抑制作用,且Miconazole的抑制作用具有一定的浓度依赖性,在加用Kv的特异性的阻断剂4氨基吡啶(4AP)后再加用该药不能进一步抑制Kv电流。结论低氧和Miconazole均作用于Kv通道的同一部位,支持PaSMCs膜上的Kv通道在低氧性肺血管收缩中起重要作用,而细胞色素P450氧化酶可调节细胞内的氧化还原状态,可能系一重要的氧感受器。

Study on the roles of voltage-gated potassium channels and Miconazole in hypoxic pulmonary vasoconstriction

Objective To investigate the role of voltage-gated potassium channels in the pulmonary artery smooth cells from rats in hypoxic pulmonary vasoconstriction (HPV) and interventive effects of Miconazole (a inhibitor of Cytochrome P 450).Methods The pulmonary artery smooth cells (PaSMC) from rats were harvested through enzymatic dissection of pulmonary arteries.The electric physiological properties of the voltage-gated potassium channels (Kv) of PaSMCs were studied by patch-clamp technique in the whole cell configuration.PaSMCs were immersed in cycling hypoxic liquid to creat an acute hypoxic model.The change of IKv was recorded before and after acute hypoxia as well as before and after intrevention of Miconazole with different concentrations.Results Both cycling hypoxic liquid and Miconazole with different concentrations led to obvious decrease of Kv currents.Moreover Miconazole decreased Kv currents in a concentration-dependent manner.Pretreament with 4-AP of 5 mmo/L,a blocker of Kv channels,did not led to further decrement of Kv currents.Conclusions The data present here suggest cycling hypoxic liquid and Miconazole act on the same site of Kv channels,implying an important role of plasmalemmal voltage-gated K channels in PaSMCs in HPV.Cytochrome P 450 which is a sensor of oxygen tension can regulates redox status in PaSMCs.