Potassium Loss and Water Uptake of Stimulated Frog Muscles

Abstract

Ernst and Csucs (1929) were the first to demonstrate that when stimulating the muscle directly — i.e. when the stimulating current passes through the whole muscle — changes take place in the K⁺-Na⁺-Cl^- and P- content. Mond and Netter (1930) as well as Achelis (1932) repv^.td similar results. Hodgkin and Horovitz (1959) demonstrated Na ⁺-K⁺ exchange in single muscle fibers stimulated directly. Tigyi (1956) investigated isolated frog sartorii in a Ringer solution containing K⁴² radioactive isotope. Besides potassium loss, the directly stimulated muscles showed a significant increase in specific activity. Later different authors obtained conflicting results. W decided, therefore, to reinvestigate the problem. Changes of the K⁺ and water content of frog muscle caused by the electric stimulating current were measured in order to obtain new data about the nature of these changes. We used blockers of ionic currents and of metabolism to find out their effect on the changes mentioned above.