摘要
目的:较系统地研究肌浆网(SR)内钙容量的减少对心肌细胞钙释放的影响.方法:采用肌浆网膜的钙泵抑制剂thapsigargin(TG)耗减SR内钙容量,以喷咖啡因的方法估测SR内钙容量,以局部场刺激的方法诱发全细胞的钙释放.胞内钙信号的变化均采用激光共聚焦显微镜的方法记录.结果:SR钙泵抑制剂TG以剂量依赖和非线性的时间依赖方式引致心肌细胞SR内钙容量的耗减,而钙容量的耗减可相应地引起全细胞水平的钙释放减少.但二者的变化不完全平行,SR内钙容量的少量减少即可引起胞内钙释放的显著减少,而当SR内钙耗减到一定程度后(虽然此时SR内Ca2+仍远高于胞质内钙),场刺激已很难或无法引致钙释放.结论:心肌细胞SR内钙容量对胞内钙释放具有重要的非线性调节作用.
AIM： To systematically investigate the effects of sarcoplasmic reticulum （SR） Ca^2＋ content depletion on cardiac Ca^2＋ release. METHODS： Thapsigargin, a potent SR Ca^2＋ pump inhibitor, was used to deplete the SR Ca^2＋ content. The SR Ca^2＋ content was estimated by traditional caffeine puff. The global Ca^2＋ release was evoked by local field stimulation and the intracellular Ca^2＋ signal was recorded by the laser scanning confocal microscope. RESULTS： The results showed that thapsigargin decreased the SR Ca^2＋ content in a dose-dependent and nonlinear time-dependent manner. The intracellular Ca^2＋ release decreased with the depletion of SR Ca^2＋. But these two decreases were not parallel to each other. A slight depletion of SR Ca^2＋ could lead to a significant decrease of Ca^2＋ release. When SR Ca^2＋ depleted to a certain degree （though still much higher Ca^2＋ in SR than in plasma）, only little or no Ca^2＋ release could be triggered by field stimulation. CONCLUSION： The results suggest that SR Ca^2＋ content has some important nonlinear regulatory effect on intracellular Ca^2＋ release.
出处
《第四军医大学学报》
CAS
北大核心
2005年第16期1441-1444,共4页
Journal of the Fourth Military Medical University
基金
国家自然科学基金资助(30470900)
广东省自然科学基金资助(04020253)
汕头大学研究与发展基金资助(L00015)
关键词
钙释放
显微镜检查
共焦
肌浆网
心肌/细胞学
Ca^2＋ release
microscopy, confocal
sarcoplasmic reticulum
myocardium/cytology
