Ouabain Effects on Cardiac Contraction, Action Potential, and Cellular Potassium
Transmembrane potential, isometric tension, and K42 content of sheep or calf myocardial bundles were recorded simultaneously during periods up to 30 hours. Ouabain at low concentrations (1.5 x 10-8 M/L) decreased intracellular K to a new steady level which was reached after several hours. Its value depended on drug concentration. The effect was reversible. There was a striking temporal parallelism between the potassium loss and the inotropic effect which was suggestive of a close relationship between the two phenomena. Action potentials during these experiments did not change in a consistent way.
- Accepted December 18, 1964.
- © 1965 American Heart Association, Inc.