Bound potassium in muscle.

Joining to the debate on "bound" or "freely diffusible" muscle potassium, which is still going on nowadays, direct current was perfused through couples of semimembranous and sartorius muscles of frog for 0.5 to 1 hour. It was done in normal, fresh condition on one muscle, and on the other after having it over-stimulated with ac of 110 V supposing that a part of K is immobilly bound in fresh muscles, but in the overtired muscles a part of K is released and becomes mobile. As mobile K+ migrates to the negative electrode, we could really find a difference between the behavior of the K+ content of fresh and over-stimulated muscles, in so far as there was much more K in the overstimulated muscle near the negative electrode than near the positive one, as compared with the K content of the corresponding parts of normal muscle.