Effect of denervation and ouabain on the response of the resting membrane potential of rat skeletal muscle to potassium

Abstract

The effects of denervation and ouabain on the relationship between resting membrane potential (E _M) and extracellular potassium concentration were determined for rat soleus (SOL) and extensor digitorum longus (EDL) muscles. At concentrations above 20 mM for both SOL and EDL fibres the relationship could be described adequately by the Nernst equation. Denervation resulted in reduction ofE _M and a decrease in the slope of the relationship betweenE _M and potassium concentration. 10⁻³ M ouabain produced the same effects as denervation. The results are discussed in relation to the alterations in membrane permeability previously shown to occur as a consequence of denervation. It is concluded that the lowE _M of denervated muscle is the result of an increase in membrane permeability to sodium.