Studies on (Na+K+)-activated ATPase XVII. Effect of ouabain and erythrophleine on potassium concentration and membrane potential of frog sartorius muscle

Abstract

• 1.

  1. The effect of ouabain and erythrophleine on K⁺, Na⁺ and Cl⁻ concentrations and membrane potential in frog sartorius muscle was studied in view of reports that changes in internal ionic concentrations would not be concerned in the effect of ouabain on membrane potential.

• 2.

  2. The two drugs each caused a decrease in membrane potential and K⁺ concentration. The observed change in potential agreed with the expected change calculated from the decrease in K⁺ concentration.

• 3.

  3. There was also an uptake of Na⁺, larger than the loss of K⁺, and an uptake of Cl⁻ equivalent to the excess Na⁺ uptake, as well as an uptake of water sufficient to make the entering NaCl solution isotonic.

• 4.

  4. The results are in quantitative as well as qualitative agreement with a role of ouabain- and erythrophleine-sensitive (Na⁺K⁺)-activated ATPase in the cation transport of frog sartorius muscle.