Work-Induced potassium changes in muscle venous effluent blood measured by ion-specific electrodes

Summary Modified Walker's liquid ion-exchanger microelectrodes were employed for measuring changes of K⁺ concentration in venous effluent blood from the cat gastrocnemius muscle during and after isometric tetani of various duration induced by indirect stimulation. The time course of these changes was obtained and the overall loss of K⁺ from a working muscle could thus be estimated. By comparing present results in the venous blood and previous findings of K⁺ concentration changes in the muscle extracellular space, a concentration gradient was found between the muscle and venous effluent blood.The authors wish to acknowledge the assistance of Dr. J. L. Walker in developing the ion-specific microelectrodes and for supplying them with silicone oil and Corning ion-exchanger.