[Two components of calcium-dependent potassium permeability coexist in the membrane of frog skeletal muscle].

Two components of Ca-dependent K permeabilities were demonstrated in the membrane of voltage-clamped muscles fibres by raising the internal calcium concentration with 3 mM caffeine or 0.1 microM Bay K 8644. One, which is TEA-sensitive, is enhanced by an increase of intracellular calcium and the other, which is apamin-sensitive, is inhibited by high levels of internal calcium concentration.