库容性Ca^(2+)内流介导大鼠远端结肠平滑肌收缩  

Capacitative Ca^(2+) entry mediate contraction in rat distal colon smooth muscle

作　　者：柯道平[1] 周华[1] 李忠稳[1] 孔德虎[1] 马嵘[2] 

机构地区：[1]安徽医科大学生理学教研室,安徽合肥230032 [2]美国德州北方大学卫生科学中心生理系

出　　处：《中国药理学通报》2006年第3期344-348,共5页Chinese Pharmacological Bulletin

基　　金：安徽省教育厅自然科学基金项目(No2005KJ242)

摘　　要：目的探讨库容性Ca2+内流(capac itative Ca2+entry,CCE)是否参与大鼠远端结肠平滑肌兴奋-收缩偶联过程。方法利用器官离体装置、张力换能器、Powerlab 4/25T数据采集分析系统测定远端结肠平滑肌的张力。结果毒胡萝卜素(thapsigargin,TG,10 nmol.L-1~1μmol.L-1)诱导结肠平滑肌条产生持续的张力性收缩,不同浓度TG所致的同步收缩反应张力不同。在无钙Krebs液(包含1 mmol.L-1EDTA)中使用TG将肌条培养35 m in后,再加入Ca2+2.5mmol.L-1,比未使用TG处理的肌条产生的收缩张力明显提高(99%±28%vs70%±8%)。且TG耗竭胞内钙库后再复钙所致的收缩效应,不受L型钙通道阻断剂verapam il影响,但可被SOC通道阻断剂La3+减弱。结论TG耗竭胞内钙库后再复钙诱导的大鼠远端结肠平滑肌收缩反应由CCE介导,提示CCE是提供大鼠远端结肠平滑肌收缩的激活信号Ca2+的来源之一,参与完成结肠平滑肌兴奋-收缩偶联过程。Aim To investigate whether capacitative Ca^2＋ entry involved in excitation-contraction coupling in rat distal colon smooth muscle. Methods Changes of isolated organ＇s tension were monitored with forcedisplacement transducer and Powerlab 4/25T recording system. Results Thapsigargin （10 nmol· L^-1μmol·L^-1 ） produced slowly developing sustained contractions in isolated distal colon smooth muscle strips of rats. The timed contractile responses to thapsigargin （10 n mol· L^-1-1 μmol·L^-1） were significantly different. The contractile response to Ca^2＋ reintroduction following incubation of strips in a Ca^2＋-free Krebs in the presense of thapsigargin was significantly higher than in its absence （99% ± 28% vs 70% ± 8%）. Contractile responses to Ca^2＋ reintroduction following depletion of sarcoplasmic reticulum Ca^2＋ stores with thapsigargin were attenuated by La^3＋ , while unaffected by verapamil. Conclusion Contractile responses to Ca^2＋ reintroduction following depletion of sarcoplasmic reticulum Ca^2＋ stores with thapsigargin, are mediated by capacitative Ca^2＋ entry. The results suggested that CCE provided activator Ca^2＋ for the contraction and participated in excitation-contraction process in rat distal colon smooth muscle.

关 键 词：库容性Ca^2+内流 远端结肠平滑肌 大鼠 毒胡萝卜素 

分 类 号：R-332[医药卫生] R322.45