Potassium and Sodium in Frog Muscle

Abstract

Sodium-rich frog muscles are found to extrude sodium and reaccumulate potassium at 0°C. The uptake of potassium by these muscles is studied at three different temperatures as a function of external potassium concentration, K_ex. The steady-state potassium content of the tissue is related to K_ex. by a sigmoidal cooperative curve at all temperatures. These results are compared with findings on a mammalian smooth muscle.