多索茶碱对支气管哮喘患者外周血嗜酸粒细胞钙依赖性钾离子通道的影响

目的研究多索茶碱对支气管哮喘(简称哮喘)患者外周血嗜酸粒细胞(EOS)钙依赖性钾离子(KCa)通道的作用及机制。方法分离8例哮喘急性发作期患者外周血EOS,并均分为对照组和多索茶碱孵育组,采用细胞贴附式膜片钳技术封接成功后在浴槽液中加入0.2μm ol/L血小板活化因子(PAF)激活KCa通道,比较两组EOS KCa通道动力学的改变。结果细胞贴附式时浴槽液中加入0.2μm ol/L PAF时出现电流活动,对照组通道开放概率为0.135±0.021、开放时间为(5.75±0.40)m s、关闭时间为(2.17±0.50)m s,多索茶碱孵育组其相应值分别为0.044±0.018、(2.39±0.13)m s、(23.73±2.50)m s,两组比较差异均有统计学意义(P均<0.05)。结论PAF能开放EOSKCa通道,多索茶碱可通过缩短EOS KCa通道开放时间,延长关闭时间,降低哮喘患者EOS KCa通道开放概率。

Effect of doxofylline on calcium-activated potassium channels in human peripheral blood eosinophils in asthma

OBJECTIVE: To study the effects of doxofylline on calcium-activated potassium (K(Ca)) channels of human peripheral blood eosinophils in asthma. METHODS: Peripheral blood eosinophils from patients with asthma were isolated and divided equally into two groups, a control group and a doxofylline incubated group. The data were recorded using cell-attached configuration of patch-clamp technique and the kinetic changes of K(Ca) channels activated by 0.2 micromol/L platelet activating factor (PAF) were compared. RESULTS: As compared with the control group, the open probability of the K(Ca) channels decreased from 0.135 +/- 0.021 to 0.044 +/- 0.018, the open time from (5.75 +/- 0.40) ms to (2.39 +/- 0.13) ms, while the close time increased from (2.17 +/- 0.50) ms to (23.73 +/- 2.50) ms in the doxofylline incubated group. The differences were significant between the two groups (all P < 0.05). CONCLUSION: Doxofylline could decrease the open probability of the channels as a result of both the shortening of open period and the prolongation of close time.