Relationship of epithelial membrane potentials to corneal potential

The rabbit corneal potential arises as the sum of three steps across the epithelium. These occur across the squamous cell outer membrane, at the transition region between wing and basal cells, and across the basal cell inner membrane. Variations in corneal potential are inversely proportional to outer membrane potential. The latter can be described as the sum of a Goldman-Hodgkin-Katz diffusion potential and a shunt potential. Apparently the central potential step is generated by shunt currents. The potential of the inner membrane can be explained on the basis of potassium permeability and distribution. The proposed origin of the outer membrane potential offers an explanation of responses of corneal potential to silver ions and agents which elevate tissue levels of cyclic AMP.