ABSTRACT
Aim To observe effects of hypertension on contractile/diastolic function and calcium transient in rats ventricular myocytes. Methods The model of one-kidney-one-clip (1k1c) hypertensive rat was pre-pared by partially ligating the left renal artery and removing the right kidney. Left ventricular 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 1k1c hypertensive rat cardiac myocytes. However their intracellular 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 ratio-cell 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.