Denervation and the Electrogenesis of the Sodium Pump in Frog Skeletal Muscle

Abstract

THE sodium pump in frog skeletal muscle has been found¹ to be electrogenic in experiments in which sodium-rich muscles were immersed in recovery fluid containing 10 mM potassium and the mean membrane potential measured by means of the microelectrode technique² during active sodium excretion. It was found that the measured potential, E_m, was greater than the potassium-equilibrium potential, E_K, by about 11 mV, suggesting that uptake of potassium ions may not be tightly coupled to excretion of sodium ions in a 1 : 1 manner³, but that potassium ions may be drawn into the muscle fibres under the influence of the potential generated by the sodium pump. The electrogenic nature of the excretion of sodium ions in muscle has also been confirmed in other laboratories^4,5.