论文部分内容阅读
目的 :探讨内皮素 1(ET 1)对大鼠心肌细胞正性肌力作用的细胞内机制。方法 :将离子敏感性荧光指示剂indo 1和SNARF 1载入大鼠心室肌细胞内 ,荧光显微镜法同时测定细胞内Ca2 + 浓度 ([Ca2 + ]i)、pH(pHi)和细胞长度。结果 :在 17例大鼠心肌细胞中 ,只有 8例对灌注ET 1表现出明显的细胞缩短反应 ,即正性肌力作用 ,占47% ,另 9例对灌注ET 1没有反应。ET 110 0nmol/L可使细胞缩短的幅度增加至给药前的 (2 0 2 .85± 2 8.13) % ,P <0 .0 1;[Ca2 + ]i瞬间变化的幅度增加至给药前的 (132 .0 6± 10 .93) % ,P <0 .0 5 ;pHi与对照组相比轻度增加。结论 :ET 1可直接作用于大鼠心室肌细胞引起正性肌力作用 ,其作用机制是增加了 [Ca2 + ]i瞬间变化 ,而不是明显增加了 pHi
Objective: To investigate the intracellular mechanism of endothelin 1 (ET 1) on inotropic rat cardiomyocytes. Methods: The ion sensitive fluorescent indicators indo 1 and SNARF 1 were loaded into rat ventricular myocytes. The intracellular Ca 2+ concentration ([Ca 2+] i), pH (pHi) and cell length were determined by fluorescence microscopy. RESULTS: Of the 17 rat cardiomyocytes, only 8 showed a significant shortening response to ET 1 perfusion, ie, inotropic effects, accounting for 47% of the total, while the other 9 had no response to ET 1 perfusion. ET 110 0nmol / L could increase the cell shortening to (2 0 2 .85 ± 2 8.13)% before administration, P <0.01; the amplitude of [Ca 2+] i transient change increased to (132.0 ± 10.93)%, P <0.05; pHi slightly increased compared with the control group. CONCLUSION: ET1 can directly act on rat ventricular myocytes to induce positive inotropic effect, and its mechanism of action is to increase the transient change of [Ca2 +] i rather than increase the pHi