正常大鼠心室肌细胞钠、钙和钾离子流记录和特点

目的研究正常Sprague—Dawley大鼠外膜、中膜和内膜心室肌细胞钠离子电流（INa）、L-型钙离子电流（ICa-L）、瞬时外向钾离子电流（I60）、延迟整流性钾离子电流（IK）、内向整流性钾离子电流（IK1）的特点。方法采用酶消化法获得大鼠外膜、中膜和内膜心室肌细胞，以全细胞膜片钳技术记录心室肌细胞INa、ICa-L、Ito、IK和IK1。结果外膜至内膜心室肌细胞Ito电流密度逐渐减小，而外膜至内膜心室肌细胞INa、ICa-L、IK和IK1的电流密度无差异（P〉0．05）。结论大鼠心室肌细胞Ito存在分层差别，INa、ICa-L、IK和IK1不存在分层差别。

The Characteristics of Sodium,Calcium,Potassium Current from Ventricular Myocytes of Normal Spraque-Dawley Rat

Objective To investigate the characteristics of sodium current （ INa）, L - type calcium current （ICa-L）, transient outward current （Ito）, delayed rectifier potassium current （IK） and inward rectifier potassium current （ IK1 ） from epicardial, mid - cardial and endocardial ventricular myocytes of normal Sprague - Dawley rat. Methods Epicardial, mid - cardial and endocardial ventricular myocytes were ioslated by enzyme. INa, ICa-L, Ito, IK and IK1 were successfully recorded by whole cell patch clamp configuration. Results ho current densities were gradually decreased from epicardial to endocardial ventficular myocytes, and INa, ICa-L, IK and IK1 current densitis did not change significantly（ P 〉 0.05）. Conclusion There are regional differences in the distribution of Ito in rat epicardial, mid - cardial and endocardial ventricular myocytes, but there are no regional differences in the distribution of INa, ICa-L, IK and IK1 in rat epieardial, mid - cardial and endocardial ventricular myocytes.