"Increasing the Na⁺ permeability occurs when additional Na⁺ channels are added to the membrane.

With the addition of more Na+ channels more positive Na⁺ ions will move into the cell.

This inward movement of positive Na⁺ ions will cancel out more of the K⁺ ions moving out.

The result will be that the cell membrane potential will move towards the Na⁺ equilibrium potential."

courtesy of Robert H. Parsons, Ph.D., Rensselaer Polytechnic Institute, used with permission