The interaction of potassium with the activation of anomalous rectification in frog muscle membrane

J Physiol. 1981 Aug;317:497-508. doi: 10.1113/jphysiol.1981.sp013839.


1. Inward rectification of frog muscle membrane was analysed with the Vaseline gap method. 2. Hyperpolarization, under voltage clamp, produced inward potassium currents, which had a component that activated with a time constant, tau K. 3. The activation time constant tau K of the inward potassium currents was voltage dependent. For a given external potassium concentration, the time constant was maximal for potentials near the potassium equilibrium potential, EK. 4. The potassium chord conductance gK, had a sigmoidal voltage dependency, increasing initially e-fold per 11.6 mV of hyperpolarization. 5. When the internal potassium concentration was fixed, raising external potassium induced a shift of the tau K-V and the gK-V relations in the positive direction along the voltage axis. That shift was comparable to the change in EK. 6. No shift of the tau K-V and the gK-V relations was observed when the internal potassium was reduced from 150 to 50 mM. 7. Changes of internal sodium concentration between 5 and 100 mM did not significantly effect the magnitude of inward rectification.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • Electric Conductivity
  • In Vitro Techniques
  • Kinetics
  • Membrane Potentials / drug effects
  • Muscles / physiology*
  • Potassium / pharmacology
  • Potassium / physiology*
  • Rana catesbeiana
  • Rana temporaria
  • Sodium / pharmacology


  • Sodium
  • Potassium