【摘要】 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更多还原

【Abstract】 Objective: Our aim was to study the intracellular mechanisms of the positive inotropic effect of endothelin 1 (ET 1). Methods: We used microscopic spectral imaging method to monitor [Ca 2+ ]i, pHi, and cell shortening simultaneously with fluorescent indicator indo 1 and SNARF 1 in isolated single ventricular myocyte of rats. Results: The ET 1 increased cell shortening in 8 of 17 rats (47%). Exposure of ventricular myocytes to ET 1 (100nmol/L) significantly increased the amplitude of cell shortening to(202.85±28.13)% of the pretreatment (P<0.01). The [Ca 2+ ]i transient also increased to (132.06±10.93)% of the pretreatment (P<0.05). The pHi increased slightly compared with the control with no statistical significance. Conclusion: The ET 1 can act directly on single ventricular myocyte of rats to produce a positive inotropic effect that may predominantly be due to an enhanced [Ca 2+ ]i transient, rather than markedly increased pHi.更多还原