【目的】　探讨乐果对培养乳鼠心肌细胞细胞收缩功能、乳酶脱氢酶 (LDH)、天冬氨酸转氨酶 (AST)和细胞骨架的影响。【方法】　体外乳鼠心肌细胞细胞培养。【结果】　乐果可使心肌细胞收缩力减弱 ;13 2 μmol/L染毒 3h后心肌搏动频率明显降低 ,而 5 2 8μmol/L和 2 11 2 μmol/L染毒 1h后即降低 ;2 11 2 μmol/L染毒心肌细胞 ,LDH和AST漏出达最大值的时间分别为 1h和 3h ,而 13 2或 5 2 8μmol/L染毒分别为 3h和 8h。另外 ,乐果还可使心肌细胞骨架着色变浅 ,排列不规则。上述改变具有明显的剂量 效应和时程依赖性关系。【结论】　乐果对乳鼠心肌细胞有明显的毒作用 ,其机制可能涉及心肌细胞膜和线粒体膜通透性增加 ,刺激肌质网的钙泵系统摄取Ca2 +,引起细胞骨架构型改变 ,从而影响心肌的收缩功能 【Objective】 To investigate the effects of dimethoate on contractile function, lactate dehydrogenase (LDH), aspartate aminotransferase (AST) and cytoskeleton in cultured neonatal rat cardiomyocytes. 【Method】 Cell culture of neonatal rat cardiomyocytes in vitro. 【Results】 dimethoate decreased myocardial contractility; myocardial pulsatility was significantly decreased at 13 2 μmol / L for 3 h and decreased at 5 2 8 μmol / L and 2 11 2 μmol / L for 1 h; 2 11 The exposure of 2 μmol / L to cardiomyocytes resulted in 1h and 3h leakage of LDH and AST, respectively, and 13h or 528μmol / L respectively for 3h and 8h. In addition, dimethoate cardiomyocyte skeleton can also be lighter, irregular arrangement. The above changes have obvious dose-response and time-dependent relationship. 【Conclusion】 dimethoate has obvious toxic effects on neonatal rat cardiomyocytes. The mechanism may involve the increase of permeability of myocardial cell membrane and mitochondrial membrane, stimulating the uptake of Ca2 + by the calcium pump system of sarcoplasmic reticulum, resulting in the change of cytoskeleton configuration. Affect myocardial contractile function