电针“内关”穴对家兔急性心肌缺血在体心室肌细胞跨膜电位的影响

Effect of Electroacupuncture at Neiguan Point on Transmembrane Potential of the Ventricular Cells of Rabbits with Acute Myocardial Ischemia in Situ

本实验采用静脉注射垂体后叶素（2．5u／kg）造成家兔急性心肌缺血模型。用悬浮式微电极技术，在体自然呼吸条件下，观察电针“内关”对左心室肌细胞跨膜电位影响，并同步记录心电图和动脉血压。结果我们发现急性心肌缺血时，心室肌细胞静息电位、动作电位振幅、动作电位0相除极化最大速率均明显减小，而动作电位时程明显延长，同时出现除极后电位，上述电位变化均可引起心律失常。电针“内关”可使上述电位改变明显减弱，防止心室肌细胞转为具有慢反应细胞的特性，并能减少除极后电位的发生。这可能是电针“内关”能防治急性心肌缺血并发心律失常的原因之一。

Acute myocardial ischemia of rabbit was caused by Pituitrin (2. 5u/kg)intravenously. The effect of electroacupuncture (EA ) at Neiguan polnt on transmernbrane potential was observed with a suspension microelectrode technique in situ and under the condition of natural respiration; the blood pressure and electrocardiogram were recorded simultaneously- The results showed that during acute myocardial ischernia, the resting potential (RP), action potentail amplitude (APA ) and maximurn velocity of depolarization (Vmax ) were all significantly decreased, but action potential duration (APD) was markedly prolonged and after depolarization potential appeared at the sarne time. All of the above mentioned changes of potentials could cause arrhythmia t while EA at Neiguan could weaken the changes of the potentials rnarkedly,prevent the ventricular cells from changing to slow reaction cells and reduce the incidence of after depolarization potential, That may be a reason why EA at Neiguan can prevent and cure arrhythmia complicated by acute myocardial ischemia