Electrophysiological Studies on the Mechanism of Electrically Induced Sustained Rhythmic Activity in the Rabbit Right Atrium
Electrophysiological Studies on the Mechanism of Electrically Induced Sustained Rhythmic Activity in the Rabbit Right Atrium
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兔右心房电致持续节律活动机制的电生理学研究
DOI：
10.1161/01.res.42.2.199
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发表时间：
1978
影响因子：
20.1
通讯作者：
T. Matsubara
中科院分区：
文献类型：
--
作者：
T. Saito;M. Otoguro;T. Matsubara
从家兔心脏中分离无自发活动的右心房制备物。从梳状肌上肌纤维和梳状肌沿着界嵴的部分纤维记录到具有特定振荡后电位的动作电位。振荡电位的幅度和上升速率随刺激间隔的缩短而增加。在12台罗德+-S溶液中的35个制剂，持续的节律性活动导致的去极化相的增强振荡电位。持续节律活动期间的动作电位的特征是缓慢的舒张期去极化，如在窦房（SA）结。一个单一的过早刺激或一系列刺激有时会导致兴奋速率的加速，而不是抑制。持续的节律性活动保持在一个低的静息电位和自发停止时，缓慢舒张期去极化的斜率下降，最大舒张期电位增加。持续节律活动终止后的刺激既不会增加振荡电位的振幅，也不会引发进一步的持续节律活动。启动新的持续的节奏活动需要一段时间的静止之前，电刺激。这些结果表明，持续的节律性活动在本文中所描述的结果不是从折返，而是从自发产生的动作电位的心房纤维振荡后电位。
Right atrial preparations with no spontaneous activity were isolated from rabbit hearts. Action potentials with specific oscillatory after potentials were recorded from some fibers in the upper pectinate muscle and in the pectinate muscle along the crista terminalis. The amplitude and rate of rise of the oscillatory potential increased as the stimulus interval decreased. In 12 of 35 preparations in Tyrode+-s solution, sustained rhythmic activity resulted from the depolarizing phase of the enhanced oscillatory potential. The action potential during sustained rhythmic activity was characterized by slow diastolic depolarization, as in the sinoatrial (SA) node. A single premature stimulus or a train of stimuli sometimes caused an acceleration of the rate of excitation rather than its suppression. Sustained rhythmic activity was maintained at a low resting potential and ceased spontaneously when the slope of the slow diastolic depolarization decreased and the maximum diastolic potential increased. Stimulation just after termination of sustained rhythmic activity neither increased the amplitude of the oscillatory potential nor initiated further sustained rhythmic activity. Initiation of new sustained rhythmic activity required a period of quiescence before electrical stimulation. These results suggest that the sustained rhythmic activity described in this paper results not from reentry but, rather, from spontaneous generation of action potentials by the atrial fibers having oscillatory afterpotentials.