间羟胺对大鼠心室肌细胞动作电位及L-型钙电流的影响

目的观察α肾上腺素能受体激动剂间羟胺对大鼠心室肌动作电位及L-型钙电流的影响。方法采用全细胞膜片钳方法,记录离体大鼠心室肌细胞动作电位和L-型钙电流。结果 200μmol/L间羟胺可使心室肌细胞L-型钙电流增大（P〈0.05）,动作电位时程（APD）明显延长（P〈0.01）,动作电位复极50%和90%时间（APD50and APD90）明显延长（P〈0.01）。100μmol/L酚妥拉明可使增大的的L-型钙电流和APD、APD50、APD明显恢复。结论间羟胺可明显延长大鼠心室肌动作电位时程,而酚妥拉明可不同程度地拮抗此效应。

Effects of Metaraminol on Action Potentials and ICa-L in Rat Ventricular Myocytes

Objective To investigate the effects of metaraminol on action potential（AP） and L-type calcium channel current（ICa-L） in isolated rat ventricular myocytes Methods Action potentials and L-type calcium current in the isolated ventricular myocytes were recorded by whole-cell recording patch clamp technique.Results Metaraminol 200 μmol/L could increase L-type calcium current（P〈0.05） and prolong the duration of action potential（APD）,50% and 90% of duration of action potential（APD50 and APD90） significantly（P〈0.01）.Phentolamine 100μmol/L restored the increased ICa-L and APD,APD50 and APD90.Conclusion Metaraminol can significantly increase ICa-L and prolong APD,APD50 and APD90 in rat ventricular myocytes and phentolamine can antagonize the effects of metaraminol.