【摘要】 用Fura-2/AM技术直接观察前胡丙素（Pra-C）对培养大鼠心室肌细胞内游离钙的影响。结果显示Pra-C浓度为0.1～1.0μmol·L^-1可明显抑制CaCl₂,高K⁺和Bay K 8644引起[Ca²⁺]i增加,并且有剂量—效应关系,对ouabain引起的[Ca²⁺]i增加无明显作用。结果提示Pra-C降低心肌细胞[Ca²⁺]i的作用与抑制电压依赖性钙通道有关。更多还原

【Abstract】 The negative inotropic effect of Pra-C was supposed to be related to the blocking of extracellular calcium influx but direct evidence is not known. We, therefore, examined the effects of PraC on [Ca²⁺] i in isolated rat ventricular myocytes using the fluorescent Ca²⁺- indicator Fura-2/AM. It was found that Pra-C inhibited the elevation of [Ca²⁺]i induced by potassiumdepolarization, high extracellular calcium and calcium agonist Bay K 8644 in a dose-dependent manner. At 1.0 μmol · L^-1, it decreased the [Ca²⁺]i at the presence of 75 mmol · L^-1 KCl, 10 mol · L^<sup>-1 CaCl and 3 μmol · L^-1 Bay K 8644 by 50, 31 and 42% respectively. No significant effect on ouabain evoked [Ca²⁺]i increase was found, showing that it does not affect sarcolemmal Na⁺ —Ca²⁺exchange. These results further indicate that Pra-C may decrease the [Ca²⁺]i of myocyte by blocking voltage-dependent calcium channels.更多还原