溴化异丙托品对哮喘豚鼠气管平滑肌细胞钾通道的作用

Study on effect of ipratropium bromide on potassium channel in TSMC of asthma guinea pigs

目的 研究异丙托溴铵和沙丁胺醇对哮喘豚鼠气管平滑肌细胞大电导钙激活钾通道 [largeconductancecalciumactivatedpotassium (BKCa)channel]的作用。方法 建立哮喘豚鼠模型。急性分离单个的豚鼠气管平滑肌细胞 ,以膜片钳技术的内面向外式记录单通道电流。结果 哮喘组豚鼠通道开放概率 (P0 )降低 ,和对照组相比差异有显著性 (P <0 .0 1 )。哮喘组通道开放时间常数 (τ0 1 和τ0 2 )缩短 ,关闭时间常数 (τc1 和τc2 )延长 ,与对照组相比差异有显著性 (P <0 .0 1 )。异丙托溴铵或沙丁胺醇对哮喘BKCa通道的增强作用主要表现为延长通道开放时间常数 ,缩短关闭时间常数。τ0 1 ,τ0 2 ,τc1 和τc2 与哮喘组相比差异有显著性(P <0 .0 1 )。结论 哮喘豚鼠BKCa通道的活动显著降低。BKCa通道活动的减弱表现为 ,通道开放时间常数缩短 ,关闭时间常数延长。异丙托溴铵与沙丁胺醇可逆转哮喘对BKCa通道的作用 。

OBJECTIVE: To study the effects of ipratropium bromide and salbutamol on large conductance calcium activated potassium (BKCa) channel in trachea smooth muscle cell (TSMC) from guinea pig with asthma. METHODS: The asthma guinea pig model was established. Single TSMC was acutely isolated. Single channel currents were recorded by using the patch clamp technique in inside-out configuration. RESULTS: BKCa channel activity decreased significantly on the inside-out recording. Channel open probability (P o) of BKCa channel in asthma guinea pig reduced significantly compared with that in control guinea pig (P 01 and τ02) significantly shortened in asthma group. Closed time constants (τc1 and τc2) prolonged significantly. Ipratropium bromide and salbutamol reversed the effect of asthma on BKCa channel. P0 incresed, τ01 and τ02 were prolonged markably. τc1 and τc2 were shortened. CONCLUSION: BK Ca channel activity decreased significantly in asthma guinea pig. Ipratropium bromide and salbutamol reversed the effect of asthma on BK Ca channel. The relaxed effect of ipratropium bromide and salbutamol on TSMC may be partly mediated via activation of BKCa channel.