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目的探讨镉（Ｃｄ）对心肌的毒性作用机制及硒的保护效应。方法在培养的Ｗｉｓｔａｒ大鼠乳鼠心肌细胞上观察了镉对膜电位活动的影响及亚硒酸钠和硒代蛋氨酸的保护作用。结果镉使心肌细胞动作电位幅值（ＡＰＡ）、超射（ＯＳ）、阈电位（ＴＰ）、最大舒张电位（ＭＤＰ）及最大除极速率（Ｖｍａｘ）显著降低；复极化时程（ＡＰＤ）明显缩短；动作电位发放频率（ＡＰＦ）明显加快。硒与镉按等摩尔浓度加入（１０μｍｏｌ／Ｌ），亚硒酸钠和硒代蛋氨酸均可减轻镉对心肌细胞动作电位参数ＡＰＡ、ＴＰ、ＭＤＰ、Ｖｍａｘ等的影响，但两种硒化合物对动作电位复极化时程的影响表现不一致，前者延长ＡＰＤ，后者未能改变镉对ＡＰＤ的影响。结论镉能抑制心肌细胞的跨膜电位；亚硒酸钠和硒代蛋氨酸均可不同程度地减轻镉对心肌细胞动作电位的影响。
Objective To investigate the toxic mechanism of cadmium (Cd) on myocardium and the protective effect of selenium. Methods The effects of cadmium on the membrane potential and the protective effects of sodium selenite and selenomethionine were observed on cultured neonatal rat cardiomyocytes. Results Cadmium significantly decreased the amplitude of APA, TP, MDP and Vmax. The mean value of APD, Significantly shortened; action potential release frequency (APF) significantly accelerated. Selenium and cadmium were added in equal molar concentrations (10μmol / L). Both sodium selenite and selenomethionine could reduce the effects of cadmium on the action potential parameters APA, TP, MDP and Vmax of cardiomyocytes. However, The effects of potential repolarization duration are inconsistent. The former prolongs APD, while the latter fails to change the effect of cadmium on APD. Conclusion Cadmium can inhibit the transmembrane potential of cardiomyocytes. Both sodium selenite and selenomethionine can reduce the effect of cadmium on the action potential of cardiomyocytes to varying degrees.