哮喘豚鼠模型支气管平滑肌钙通道特性的变化

目的探讨钙离子通道变化与支气管哮喘豚鼠模型气道高反应性的关系.方法利用膜片钳技术细胞贴附式方法测定哮喘A组(4只,22个细胞)和正常对照A组(5只,25个细胞)支气管平滑肌细胞(BSMCs)电压依赖性钙离子通道动力学变化,全细胞式测定哮喘B组(5只,25个细胞)和正常对照B组(6只,24个细胞)BSMCs内向峰值钙电流.结果(1)BSMCs钙通道开放时间哮喘A组为(1.70±0.40)ms,正常对照A组为(0.70±0.10)ms,两组开放时间比较差异有显著性(P＜0.01);哮喘A组BSMCs钙通道关闭时间为(5.7±0.6)ms,正常对照A组为(7.9±0.4)ms,两组比较差异有显著性(P＜0.01);开放概率哮喘A组为(0.40±0.10)%,正常对照A组为(0.20±0.20)%,哮喘A组较正常对照A组增加了46%,两者比较差异有显著性(P＜0.01);(2)哮喘B组BSMCs平均内向峰值钙电流为(-54±23)PA(微微安培),正常对照B组为(-25±8)PA,哮喘B组较正常对照B组增加了1.17倍,两组比较差异有显著性(P＜0.01).结论哮喘豚鼠BSMCs钙离子通道活性增加,可能是气道高反应性主要原因之一.

Changes of Ca2+ channel behaviors in bronchial smooth muscle cells of asthma guinea-pig model

OBJECTIVE: To investigate the relationship between the change of calcium channel behavior in bronchial smooth muscle cells (BSMCs) and the airway hyperresponsiveness in guinea-pigs with asthma. METHODS: The changes of calcium channel dynamics in BSMCs of 4 asthma guinea-pig models (22 cells) and 5 normal guinea-pigs (25 cells), and the inner peak calcium current in BSMCs of 5 asthma guinea-pig models (25 cells) and 6 normal guinea-pigs (24 cells) were determined by patch-clamp techniques. RESULTS: (1) The open time of calcium channel in BSMCs of asthma group was (1.70 +/- 0.40) ms, 2.32 times as much as that of control group (0.70 +/- 0.10) ms; the close time of calcium channel in BSMCs of asthma group (5.7 +/- 0.6) ms, was significantly shorter that that of control group (7.9 +/- 0.4) ms; The open probability in asthma group (0.40 +/- 0.10)% was significantly increased than that of control group (0.20 +/- 0.20)%, (P < 0.01); (2) The inner peak calcium current in BSMCs of asthma group was (-54 +/- 23) PA, 1.17 times as muth as that of control group (-25 +/- 8) PA, (P < 0.01). CONCLUSION: The enhanced activity of calcium channel an BSMCs of asthma guinea-pig mudels may be one of the important factors responsible for the airway hyperresponsiveness.