Model of the Current-Voltage Relation for a Skin Pore

摘要

Using a Nernst-Planck model, we show that the current density in a membrane's pore as a function of voltage has three types of behavior: a quasi-ohmic behavior at low voltages, with a small slope, a non-ohmic linear dependence at large voltages, with a large slope, and a nonlinear transition region at intermediate voltages. The magnitude of the quasi ohmic current from low voltages depends mainly on the height of energy barrier inside the pore, w, through an exponential term, e~w. The low voltages domain is experimentally accessible and almost unexplored, despite the fact that it can offer direct information about the energy barrier inside a pore. The model has only two assumed parameters, the energy barrier height, w, and the relative size of the entrance region of the pore, r, with a clear physical meaning, an important advantage for fitting and interpreting experimental data. This simple model for the current-voltage nonlinearity is a good starting point for explaining the electrical behavior of the skin at low voltages.