INFLUENCE OF ADRENALECTOMY ON MEMBRANE POTENTIAL OF SINGLE SKELETAL MUSCLE CELLS

Single muscle cells of the isolated diaphragm of adrenalectomized and control rats were punctured with microelectrodes, and the membrane resting potentials were measured. In 371 cells of 7 adrenalectomized animals we found a mean resting potential of -84.4 (s=± 6.3) mV; in 347 cells of 5 control animals we found a mean resting potential of -85.1 (s=± 6.5) mV. - I. e. there is no significant difference in the resting potentials between adrenalectomized and control rats. The measured potentials (Em) agree with the values calculated by the equation of Hodgkin and Horowicz (EK + Na). The calculation bases upon measured intra- and extracellular concentrations of sodium and potassium. These findings suggest that the in vivo decreased resting potentials in adrenalectomized rats are due to the increased extracellular potassium concentration. There are no indications to a change of the total conductivity of the cell membrane for ions. © 1968 Springer-Verlag.