成年大鼠心室肌细胞表达多种电压门控钠通道α亚型

摘要

Objective To observe the expressions of voltage-gated sodium channel (NaCh)αsubunits in adult rat ventricular myocytes.Methods Single ventricular myocytes were isolated from adult rat heart.Expressions of various αsubunits (Nav1.1,Nav1.2,Nav1.3,Nav1.5,Nav1.6 and Nav1.7)of NaCh in the ventricular myocytes were detected by immunocytochemistry staining.Sodium current was recorded by whole-cell patch clamp method. Results The neuronal subunits Nav1.1,Nav1.6 and Nav1.7 as well as the cardiac subunit Nav1.5 of NaCh were expressed in adult rat ventricular myocytes.Nav1.1,Nav1.5 and Nav1.7 were distributed along the cell membrane of the ventricular myocytes and around the transverse tubule;Nav1.6 was labeled along the cell membrane by lengthways.All these subunits were not colocalized with Cx43 at the intercalated disc.Both transient sodium current (I Na,T )and late sodium current (I Na,L )were recorded from adult rat ventricular myocytes.Conclusion Various neuronal subunits (Nav1.1,Nav1.6 and Nav1.7)as well as cardiac subunit (Nav1.5 )of NaCh were expressed in adult rat ventricular myocytes,which is important for normal function of I Na,T and I Na,L .%目的 观察成年大鼠心室肌细胞上电压门控钠通道不同亚型的表达情况.方法 采用酶解消化法分离成年大鼠心室肌细胞,利用免疫荧光染色结合激光共聚焦技术检测心室肌细胞钠通道 α亚型Nav1.1、Nav1.2、Nav1.3、Nav1.5、Nav1.6、Nav1.7的表达及分布情况,采用全细胞膜片钳技术记录心室肌细胞钠电流.结果 成年大鼠心室肌细胞除表达心脏型钠通道亚型Nav1.5之外,还表达神经型钠通道亚型Nav1.1、Nav1.6和Nav1.7,不表达Nav1.2和Nav1.3.Nav1.5分布于横小管周围,Nav1.1和Nav1.7亦呈点状分布于横小管区域.Nav1.6表达稍弱,沿心室肌细胞长轴纵向分布,闰盘处未见钠通道各 α亚型的表达.膜片钳结果显示成年大鼠心室肌细胞表达快钠电流(I Na,T)及晚钠电流(I Na,L).结论 成年大鼠心室肌细胞表达心脏型钠通道亚型(Nav1.5)和多种神经型钠通道亚型(Nav1.1、Nav1.6和Nav1.7),这可能有助于维持心肌细胞的正常电生理活动.