Abstract
The present paper deals with isometric tension-development of glycerol extracted fiber bundles prepared from normal and experimentally induced failing hearts of dog, and also from rabbit psoas muscles. It was shown that there was no qualitative difference between normal cardiac and skeletal fibers under various conditions of pH and ionic milieu. Reduced tension-development was observed in fibers extracted from both right (failing) and left (normal) ventricle of dogs with right-sided heart failure. In Ca free medium, lower concentrations of ouabain had no effect, while in higher concentrations ouabain inhibited tension-development of normal cardiac fibers. In Ca containing medium, lower concentrations of ouabain counteracted the inhibitory effect of Ca, while in contrast higher concentrations augumented the effect. Similar actions of this drug were also observed in failing cardiac fibers as well as in skeletal fibers.
