EFFECTS OF CELLULAR UNCOUPLING ON CONDUCTION IN ANISOTROPIC CANINE VENTRICULAR MYOCARDIUM
EFFECTS OF CELLULAR UNCOUPLING ON CONDUCTION IN ANISOTROPIC CANINE VENTRICULAR MYOCARDIUM
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DOI：
10.1161/01.res.63.5.879
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发表时间：
1988-11-01
影响因子：
20.1
通讯作者：
MOORE, EN
中科院分区：
文献类型：
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作者：
BALKE, CW;LESH, MD;MOORE, EN
在犬灌流心室心外膜组织切片上进行实验，以确定1.0-2.0 mM庚醇（一种解偶联剂）对心肌纤维定向纵向和横向传导的影响。在添加庚醇之前和之后，测量了近端和远端成对心外膜电极之间的传导速度，这些电极横向和纵向于通过以2，000毫秒的基本周期长度从组织的一个边缘起搏诱发的传导波阵面的方向。在一组单独的组织中，使用双极正交电极在1cm × 1cm的区域中的40至45个部位顺序地标测心外膜激活。在引入庚醇之前和引入庚醇之后30分钟的2cm面积。在第三组组织中，用标准微电极技术记录跨膜电位，以确定庚醇对动作电位特性的影响。庚醇没有显着影响动作电位振幅或最大去极化率。在1.0 mM庚醇后，传导速度在1-2分钟内开始降低，并在15-20分钟内达到稳定状态。纵向上的传导速度从0.56 ± 0.55的对照值降低。0.13至0.46 . ±. 0.10 M/sec（p = 0.002）。纵向传导速度与横向传导速度之比从2.54 ± 0.01增加到2.54 ± 0.01。1.00至2.94 .+-。0.82（p = 0.042）。因此，庚醇优先减慢横向方向上的传导。因为庚醇对活性膜性质没有很大影响，我们使用电缆方程计算有效结电阻率变化的时间过程，其从133.2 Ω上升到133.2 Ω。. cntdot.在庚醇之前的312.2 Ω. . cntdot.在庚醇给药后30分钟，我们得出结论，庚醇通过选择性地增加结电阻率来减慢传导速度。在横向方向上的传导的优先减慢最有可能是由于在横向方向上每单位距离遇到的结电阻比在纵向方向上更多的事实。
Experiments were performed on canine superfused ventricular epicardial tissue slices to determine the effects of 1.0-2.0 mM heptanol, an uncoupling agent, on conduction longitudinal and transverse to myocardial fiber orientation. Conduction velocities were measured between proximal and distal pairs of epicardial electrodes oriented transverse and longitudinal to the direction of a conducted wavefront evoked by pacing at a basic cycle length of 2,000 msec from one margin of the tissue before and after the addition of heptanol. In a separate group of tissues, the dual bipolar orthogonal electrode was used to sequentially map epicardial activation at 40 to 45 sites in a 1 cm .times. 2 cm area before and 30 minutes after the introduction of heptanol. In a third group of tissues, transmembrane potentials were recorded with standard microelectrode techniques to determine the effects of heptanol on action potential characteristic. Heptanol did not significantly effect action potential amplitude or maximum rate of depolarization. After 1.0 mM heptanol, conduction velocity began to decrease in 1-2 minutes and reached a steady state in 15-20 minutes. Conduction velocity in the longitudinal direction decreased from a control value of 0.56 .+-. 0.13 to 0.46 .+-. 0.10 M/sec (p = 0.002). The ratio of longitudinal to transverse conduction velocities increased from 2.54 .+-. 1.00 to 2.94 .+-. 0.82 (p = 0.042). Thus, heptanol preferentially slowed conduction in the transverse direction. Because heptanol did not greatly influence active membrane properties, we used cable equations to calculate the time course of the changes in effective junctional resistivity, which rose from 133.2 .OMEGA. .cntdot. cm before heptanol to 312.2 .OMEGA. .cntdot. cm 30 minutes after heptanol administration. We conclude that heptanol slows conduction velocity by selectively increasing junctional resistivity. The preferential slowing of conduction in the transverse direction is most likely due to the fact that more junctional resistances are encountered per unit distance in the transverse than in the longitudinal direction.