The selectivity of the delayed potassium conductance of frog skeletal muscle fibers.

A voltage-clamp technique was used to measure reversal potentials of delayed currents in frog skeletal muscle fibres immersed in solutions containing Li2SO4,Na2SO4,K2so4,Rb2SO4, or Cs2SO4. The selectivity sequence found for the underlying permeability mechanism was K greater than or equal to Rb greater than Cs greater than Na greater than or equal to Li.