【摘要】 目的 :探讨延迟整流钾通道 (Kv) ,高电导钙激活钾通道 (BKCa)和ATP敏感钾通道 (KATP)在大鼠支气管平滑肌张力调控中的作用。方法 :以特异性钾通道阻断剂为工具 ,采用体外等长张力测定观察钾通道对静息和收缩状态下支气管张力的影响。结果 :①KV阻断剂 4 aminopyridine(4 AP)诱发大鼠支气管平滑肌产生浓度依赖性收缩反应 ,而BKCa阻断剂tetraethylammonium(TEA)和KATP阻断剂 glibenclamide(Glib)对其无影响。②去除上皮对 4 AP诱发大鼠支气管平滑肌收缩反应无影响 ,而钙通道阻断剂nifedipine对其有显著抑制效应。③在 0 .1mmol/L组胺或 50mmol/LKCl诱发支气管平滑肌收缩之前或之后 ,加入TEA(1 ,5mmol/L)或 0 .1mmol/L 4 AP均显著增强二者诱发的收缩反应 ;而Glib(1 0 μmol/L)对其无明显影响。 结论 :Kv参与大鼠支气管平滑肌静息张力的调控 ,而BKCa和KATP对其无影响。Kv和BKCa的关闭增强组胺及高浓度钾离子诱发大鼠离体支气管产生的收缩张力更多还原

【Abstract】 Aim: To investigate the role of three K + channels delayed rectifier K + channel(K v), large conductance Ca 2+ activated K + channel (BK Ca ) and ATP sensitive K + channel(K ATP ) in the regulation of the resting and contracting tone of rat bronchial smooth muscle (BSM). Methods: By measuring the isometric tone of bronchial strips in vitro , the regulating effects of the three K + channels on the tone of rat BSM were observed. Results: ①K V blocker 4 aminopyridine(4 AP) caused concentration dependent contraction in resting bronchial strips, but BK Ca blocker tetraethylammonium (TEA) and K ATP blocker glibenclamide(Glib) had no such effects. ②The bronchial epithelium had no effects on the contraction induced by 4 AP, but nifedipine,a Ca 2+ channel blocker, significantly suppressed it. ③ Before or after treatment with 0.1 mmol/L histamine or 50 mmol/L KCl,administration of TEA(1 or 5 mmol/L) or 0.1 mmol/L 4 AP could significantly increase the contraction induced by histamine and KCl in bronchial strips. But Glib (10 μmol/L) had no effect on it. Conclusion: Not BK Ca and K ATP but K V participated in the regulation of the resting tone in rat BSM. The closure of BK Ca or K V increased the contracting tone induced by histamine or KCl in rat BSM in vitro , but K ATP had no such effect on it.更多还原