The effect of intercellular medium salinity on the dielectric constant of cell membranes and the excitation thresholds of the action potential

Abstract

A mechanism for axon swelling and subsequent compression in the area of action potential passage is considered. It is shown that the dynamics of changes in the radius of the axon during the passage of the action potential can be explained by changes in osmotic pressure. Axon swelling occurs at the leading edge of the action potential when Na+ ions flow from the extracellular electrolyte into the intracellular space, and subsequent compression occurs at the trailing edge during the ejection of K+ ions. The change in dielectric constant of the axon membrane is also discussed, and a possible explanation for the decrease in the excitation threshold of the action potential with an increase in salinity of the external electrolyte is proposed.