心房峡部L型钙电流特征的研究

The study on the characters of L-type calcium current of atrial isthmus

目的研究心房峡部L型钙电流的特性,探讨心房峡部参与心律失常的机制。方法新西兰大白兔15只,麻醉后取心脏,灌流后分离右心房峡部及游离壁,利用全细胞膜片钳技术,对比观察心房峡部和右心房游离壁L型钙电流的电流密度,并观察异丙肾上腺素灌流后,其电流密度的变化。结果正常状态下,心房峡部和右心房游离壁L型钙电流的电流密度分别为-(7.03±0.71)pA/pF、-(6.30±0.61)pA/pF,二者比较差异无显著意义(P>0.05)。异丙肾上腺素灌流后,心房峡部和右心房游离壁L型钙电流的电流密度分别为-(11.01±0.46)pA/pF、-(8.51±0.31)pA/pF,两处的L型钙电流均显著增大,且心房峡部的L型钙电流密度显著大于右心房游离壁(P<0.01)。结论L型钙电流的异常变化可能是心房峡部参与心律失常发生机制的重要因素。

Objective To studythe characters of L- type calcium current （ICa,L） of atrial isthmus,and to investigate the mechanism of arrhythmias related to atrial isthmus.Metlods Hearts of 15 New zeland rabbits were cut after anesethesia. The fight atrial isthmus and free wall were incised after Langendorff peffusion. ICa, L of the two parts were recorded using the whole cell configuration of voltage-clamp techniques. In normal condition and isoproterenol perfusion, ICa, L of atrial isthmus and right atrial free wall was compared. Results In normal condition, ICa, L of atrial isthmus was not significant higher than that of right atrial free wall [ - （ 7.03 ±0. 71 ） pA/pF vs - （6.30 ±0. 61 ） pA/ pF].Afier peffused with isoproterenol, ICa,L of atrial isthmus and free right free wall were - （11.01 ± 0.46）pA/pF and -（8.51±0. 31） pA/pF respectively, all higher than those in normal condition, and ICa, L of atrial isthmus was significantly higher than that of right atrial free wall （ P 〈0.01）.Conclusion The anomaly change of ICa,L may be the important mechanism of arrhythmia that atrial isthmus involved in.