On the mechanism of ouabain toxicity in Purkinje and ventricular muscle fibers at rest and during activity.
On the mechanism of ouabain toxicity in Purkinje and ventricular muscle fibers at rest and during activity.
复制标题
关于哇巴因对浦肯野和心室肌纤维在休息和活动期间的毒性机制。
DOI：
10.1016/0002-9149(71)90226-8
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发表时间：
1971
期刊：
影响因子：
--
通讯作者：
M. Vassalle
中科院分区：
文献类型：
--
作者：
P. Polimeni;M. Vassalle
浦肯野和心室肌纤维负载42钾，并测量组织放射性。同时记录跨膜电位。钾通量的变化估计从组织放射性的变化与准备在休息或电刺激。在哇巴因存在下重复相同的程序。结果表明，哇巴因引起（1）小幅度降低（2）刺激的浦肯野纤维钾摄取减少约50%;（3）刺激的心室肌纤维钾摄取的小幅度增加消失;（4）刺激的浦肯野纤维钾流出的小幅度减少;（5）静息时心室肌纤维钾外流明显减少;（6）浦肯野纤维的不兴奋性比心室肌纤维更频繁，尽管哇巴因在浦肯野纤维中的浓度要小得多。得出结论：（a）活性纤维比静止纤维对哇巴因毒性更敏感，因为通常离子通量的增加（因此是主动离子转运）与活性的关系被哇巴因降低或消除;和（B）浦肯野纤维对哇巴因比心室肌纤维更敏感，因为随着刺激的开始，主动离子转运的增加几乎比心室肌纤维大一个数量级。浦肯野纤维。
Purkinje and ventricular muscle fibers were loaded with 42 potassium, and tissue radioactivity was measured. At the same time, trans-membrane potentials were recorded. Changes in K fluxes were estimated from the change in tissue radioactivity with the preparation at rest or stimulated electrically. The same procedures were repeated in the presence of ouabain. The results obtained show that ouabain causes (1) a small decrease (about 5 percent) in K uptake in both Purkinje and ventricular muscle fibers at rest; (2) a reduction of about 50 percent of K uptake in stimulated Purkinje fibers; (3) the disappearance of the small increase in K uptake found in stimulated ventricular muscle fibers; (4) a small reduction of K efflux in stimulated Purkinje fibers; (5) a pronounced reduction in K efflux in resting ventricular muscle fibers; and (6) a more frequent inexcitability in Purkinje than in ventricular muscle fibers, although the concentration of ouabain was far smaller for Purkinje fibers. It is concluded that (a) an active fiber is more sensitive than a resting fiber to ouabain toxicity because the usual increase in ionic fluxes (and therefore of active ion transport) with activity is reduced or abolished by ouabain; and (b) Purkinje fibers are more sensitive to ouabain than ventricular muscle fibers because the increase in active ion transport with the onset of stimulation is almost an order of magnitude greater in Purkinje fibers.