Akiyama T
Am J Physiol. 1981 Apr;240(4):H465-71. doi: 10.1152/ajpheart.1981.240.4.H465.
Transmembrane action potentials (AP) from ventricular cells during ventricular fibrillation (VF) have not been systematically studied. We have recently developed a motion-compensated micropipette holder that holds a micropipette and moves in synchrony with heart motion. AP of subepicardial ventricular cells were recorded in 14 open-chest anesthetized dogs prior to occlusion (control) of left anterior descending artery (LAD) and during first 10 min of reperfusion-induced VF. During control, characteristics (means +/- SE) of AP are: excitation rate (R), 112 +/- 4 beats/min; resting potential (Vr), -79.3 +/- 1.0 mV; overshoot potential (Vov), 17.9 +/- 1.8 mV; 90% AP duration (APD), 251 +/- 8 ms. During VF, AP from the reperfused areas are: R, 173 +/- 27 beats/min; Vr, -60.6 +/- 2.2 mV; Vov, 3.4 +/- 2.9 mV; APD, 134 +/- 9 ms (significantly different from control at P less than 0.001, except R). During VF, cells from the reperfused areas are made inexcitable with verapamil, but not by tetrodotoxin. In conclusion, during VF accurate AP recording is possible from in situ heart, and subepicardial cells in reperfused areas seem to have AP of slow-channel type.
室颤（VF）期间心室细胞的跨膜动作电位（AP）尚未得到系统研究。我们最近开发了一种运动补偿微电极固定器，它能固定微电极并与心脏运动同步移动。在14只开胸麻醉犬中，于左前降支（LAD）闭塞前（对照）以及再灌注诱导室颤的最初10分钟内，记录心外膜下心室细胞的AP。对照期间，AP的特征（均值±标准误）为：兴奋频率（R），112±4次/分钟；静息电位（Vr），-79.3±1.0 mV；超射电位（Vov），17.9±1.8 mV；90%动作电位时程（APD），251±8 ms。室颤期间，再灌注区域的AP为：R，173±27次/分钟；Vr，-60.6±2.2 mV；Vov，3.4±2.9 mV；APD，134±9 ms（除R外，与对照相比差异有统计学意义，P<0.001）。室颤期间，再灌注区域的细胞可被维拉帕米使其失去兴奋性，但不能被河豚毒素使其失去兴奋性。总之，室颤期间可从原位心脏准确记录AP，再灌注区域的心外膜下细胞似乎具有慢通道型AP。
