The effects of milrinone on conduction, reflection, and automaticity in canine Purkinje fibers.
The effects of milrinone on conduction, reflection, and automaticity in canine Purkinje fibers.
复制标题
米力农对犬浦肯野纤维传导、反射和自动性的影响。
DOI：
10.1161/01.cir.69.5.1026
复制
发表时间：
1984
期刊：
影响因子：
37.8
通讯作者：
Antzelevitch,C
中科院分区：
文献类型：
--
作者：
Davidenko,JM;Antzelevitch,C
米立酮是一种新开发的氨立酮类似物，具有强效正性肌力作用。该药物的电生理作用尚未见报道。在这项研究中，微电极技术被用来评估米立酮对犬假肌腱的电生理效应，这些假肌腱分别与正常或高k的泰罗德溶液和浦肯野纤维均匀地混合在一起，浦肯野纤维被固定在一个三室室的小室中，在这个小室中，中央部分被“缺血”溶液抑制。米立酮（0.2 ~ 20微克/毫升）对暴露在正常Tyrode溶液中的纤维的动作电位特性、耐火度或传导速度没有重大影响，但显著改善了缺血间隙制剂的传导，缩短或消除了极化后的耐火度。该药物对这些制剂中产生的反射再入也有重要作用。根据阻滞的初始水平，米力酮(1)抑制心律失常，(2)改变其频率依赖性，或(3)创造允许反射发生的条件。在均匀凹陷的纤维中也得到了类似的结果。在相同浓度下，米立酮对自动性的增强作用相对较小。因此，除了其肌力作用外，米立酮还产生重要的电生理作用。通过恢复或改善传导抑制区域的传导，该药物可发挥抗心律失常或致心律失常的作用。
Milrinone is a newly developed analogue of amrinone possessing potent positive inotropic action. Electrophysiologic actions of the drug have not been reported. In this study microelectrode techniques were used to assess the electrophysiologic effects of milrinone in canine false tendons homogeneously superfused with either normal or high-K Tyrode's solution and in Purkinje fibers mounted in a three-compartment chamber in which the central segment was depressed with an "ischemic" solution. Milrinone (0.2 to 20 micrograms/ml) caused no major changes in the action potential characteristics, refractoriness, or conduction velocity in fibers exposed to normal Tyrode's solution, but markedly improved conduction and abbreviated or eliminated postrepolarization refractoriness in the ischemic gap preparations. The drug also exerted important effects on reflected reentry generated in these preparations. Depending on the initial level of block, milrinone (1) suppressed the arrhythmia, (2) shifted its frequency dependence, or (3) created the conditions that allowed reflection to occur. Similar results were obtained in homogeneously depressed fibers. At similar concentrations, milrinone caused a relatively small enhancement of automaticity. Thus, in addition to its inotropic actions, milrinone produces important electrophysiologic effects. By restoring or improving conduction through areas of depressed conductivity, the drug may exert either antiarrhythmic or arrhythmogenic effects.