Photoelectric Demonstration of Ouabain-Induced Arrhythmias in Single Isolated Myocardial Cells and in Cell Clusters In Vitro

抄録

Photoelectric recordings showed that single isolated mouse myocardial cells cultured in vitro developed various types of arrhythmias, such as fluttering and fibrillatory beatings on addition of ouabain. Cell clusters also developed various types of arrhythmias on addition of ouabain. At low concen-trations of ouabain, the beating of cell clusters as a whole was synchronous and the rhythm of the synchronous beating was regular, but some component cells in the clusters showed rhythmic contractions accompanied with faint, fibrilla-tory beating of high frequency. At intermediate concentrations of ouabain, the beating of cell clusters as a whole was synchronous. But the rhythm of the synchronous beating was irregular. Many component cells in the clusters showed irregular, strong contractions accompanied with faint, fibrillatory beating of high frequency. The irregular, strong contractions of two cells 60 μm apart (4 cells apart) in the clusters were synchronous, but their faint, fibrillatory contractions were not. At high concentrations of ouabain, the cell clusters as a whole stopped beating, but many component cells in the clusters showed asynchronous fibrillatory beating of high frequency. Photoelectric recordings showed that the arrhythmias of component cells in cell clusters were essentially the same as those of single isolated myocardial cells. Ouabain-in-duced arrhythmias in both single isolated myocardial cells and in cell clusters disappeared on addition of quinidine sulfate. From these observations, the genesis and recovery from ouabain-induced arrhythmias of cell clusters are explained as essentially due to the genesis and recovery from arrhythmias of individual component cells of the clusters.