肾血管性高血压对大鼠心肌细胞舒缩功能、钙瞬变及其钙敏感性的影响

Effects of renovascular hypertension on contractile/ diastolic function,calcium transient and calcium sensitivity in rat ventricular myocytes

目的探讨高血压对大鼠心肌细胞舒缩功能、钙瞬变及钙敏感性的影响。方法制备一肾一狭窄(1klc)大鼠高血压模型,以酶解法急性分离左室心肌细胞,采用可视化动缘探测系统同步观察肾血管性高血压大鼠心肌细胞的收缩力、钙瞬变以及不同浓度CaCl2对肾血管性高血压大鼠心肌细胞收缩力和钙瞬变的影响。结果与假手术大鼠心肌细胞相比,肾血管性高血压大鼠心肌细胞收缩幅度明显增加,收缩和舒张速度明显加快,而其收缩期和舒张期细胞内钙、钙瞬变幅度及胞内钙动力学参数无明显变化。在不同浓度外钙作用时,高血压大鼠心肌细胞的收缩幅度—荧光强度比值曲线左移。结论在高血压的代偿期肾血管性高血压大鼠心肌细胞收缩力增加,其机制可能与高血压增加心肌细胞对钙的敏感性有关。

Aim To observe effects of hypertension on contractile/diastolic function and calcium transient in rats ventrieular myoeytes. Methods The model of one-kidney-one-clip （ 1klc） hypertensive rat was prepared by partially ligating the left renal artery and removing the right kidney. Left ventficular myocytes were enzymatically isolated. Then the contraction and calcium transient of a single cell from both normal and renovascular hypertensive rats were observed by a video-based motion edge-detection system simultaneously. Effects of calcium in various concentrations on contractile/diastolic function and calcium transient in ventricular myocytes from renovascular hypertensive rats were assessed in the same way. Results Compared with normal cardiac myocytes, the shorting amplitude and the contractile and diastolic velocity were increased significantly in lklc hypertensive rat cardiac myocytes.However their intraeellular calcium in contractile and diastolic periods, the extent of calcium transient and the parameters of intracellular calcium dynamics were unchanged. But the extracellular calcium of different concentrations could shift the Fura-2 fluorescence ratiocell shorting amplitude curve from hypertension rat myocytes to the left compared with that from normal rats. Conclusions The hypertension increases the contractility of rat cardiac myocytes, which is due to raising their sensitivity to calcium.