同步记录在位兔心跨膜动作电位与单相动作电位的对比研究

应用接触电极和悬浮微电极,同步记录比较了在位兔心左室心外膜单相动作电位和跨膜动作电位,发现MAP的复极过程与其相邻近的细胞TAP相类似;两者在心律失常和使用河豚毒索情况下所引起的形态、振幅和时程的变化也是一致的。同步记录MAP和TAP显示:证明MAP和TAP的去极相能指示兴奋到达该处细胞的确切时间。对比心表心电图、TAP、MAP以及和MAP的内在转折相比较,推断MAP的内在转折是由心表心电图的Rs波所引起;单相动作电位是在损伤电位的基础上产生的。

COMPARATIVE STUDY ON MYOCARDIUM TRANSMEM-BRANCE ACTION POTENTIALS AND MONOPHASIC ACTION POTENTILS SIMULTANEOUSLY RECORDED FROM THE RABBIT HEART IN SITU

The monophasic action potentials (MAP) and the transmembrance action potentials (TAP) were simultaneously recorded from the rabbit left ventricuiar epicardium in situ using a contact electrode and compared with those recorded with an intraceliular floating microelectrode. It was found that MAP had a repolarization time course similar to that of the transmembrance action potentials of the adjacent cells and that the changes of MAP and TAP identical in amplitude, duration, and configuration in the case of arrhythmia and administration of tetrodotoxin. Simultaneously recording TAP and MAP showed that depolarization phase of the TAP and MAP indicated the exact time of the arrival of the excitation wave at the cell. Comparcd with the findings by surface electrocardiogram configur ation and TAP, MAP and/or intrinsic deflection of MAP, we conclude that the intrinsic deflection of MAP results from Rs wave of the surface electr ocardiogram and that the formation of MAP is based on the injured potentials.