硒代蛋氨酸与亚硒酸钠对心肌细胞动作电位影响的比较

在培养的Ｗｉｓｔａｒ大鼠乳鼠心肌细胞上观察了硒代蛋氨酸与亚硒酸钠对膜电位活动的影响。结果表明，硒代蛋氨酸与亚硒酸钠（１．０，２．０，４．０ｍｇ／Ｌ）均可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；硒代蛋氨酸使复极化时程（ＡＰＤ１０、ＡＰＤ５０、ＡＰＤ９０）缩短，动作电位发放频率（ＡＰＦ）加快；而亚硒酸钠在４．０ｍｇ／Ｌ硒剂量时使所有的ＡＰＤ均延长，动作电位发放频率减慢，在作用剂量为１．０、２．０ｍｇ／Ｌ硒时，使ＡＰＤ１０延长，而ＡＰＤ５０、ＡＰＤ９０缩短。表明两种硒化合物均具有Ｃａ２＋通道阻滞作用，而亚硒酸钠还具有Ｋ＋通道阻滞作用

Comparison between Selenomethionine and Sodium Selenite on Action Potentials of Cultured Myocardiocytes

The action potentials of ventricular myocardial cells were recorded with glass microelectrodes inside the cells from neonatal Wistar rats treated with selenomethionine and sodium selenite in concentrations of 1 0,2 0,and 4 0 mg/L selenium.Both of selenomethionine and sodium selenite decreased the action potential parameters,such as action potential amplitude(APA), overshoot(OS),threshold potential(TP),maximum diastolic potential (MDP) and maximum rate of depolarization ( V max).Selenomethionine decreased the action potential duration at 10%,50% and 90% repolarization (APD 10 ,APD 50 and APD 90 ),while sodium selenite prolonged APD 10 ,APD 50 and APD 90 at dose of 4 0 mg/L selenium and decreased APD 50 and APD 90 at dose of 1 0 and 2 0 mg/L selenium.The results indicated that both sodium selenite and selenomethionine inhibit the transmembrane movement of Ca 2 and sodium selenite also inhibits transmembrane movement of K .