Figure 2.

The energies of the 9 major inorganic ions between the intra- and extracellular phases. The ΔG′ [ion]_o/i is shown for 3 cell types with greatly different resting membrane potentials. The resting membrane potential (E_N) times the faraday constant F is plotted on the x axis. Equation 2) is plotted on the y axis. The ion that has an energy approaching zero is the most permeant ion. The resting membrane potential of the 3 tissues was a Nernst equilibrium potential (13) of the most permeant ion, which in the case of heart was K⁺, in liver was Cl⁻, and in red blood cells was Cl⁻ and HCO₃⁻.