Control of Electric Potentials — Maintenance and Modulation

Abstract

A stationary PD of a certain magnitude appears to be required for normal metabolic activity of the cell, and presumably also for “normal” permeability of the cell membrane to various solutes. Accordingly, perturbations of the PD are usually associated with alterations of cellular functions, in particular of the plasma membrane (Katz, 1966; Harold, 1977). It is often difficult, however, to tell which comes first, i.e., whether a change in PD causes a change in permeability or vice versa, or whether both changes are coinciding results of some other change, for instance in the concentration of certain ions. It is also possible that permeability changes that occur with changes in PD may in reality result from alterations in the static phase boundary PD at the membrane surfaces, even though the latter are not directly related to membrane permeability.