Origin of the rising phase of gating currents.

It is suggested that the delayed rise of gating currents may result from a dielectric relaxation process within the membrane, not of the gating systems themselves but of molecules in the neighborhood of the gating systems. Such dielectric relaxation may prevent the electric fields at the locations of the gates from rapidly attaining their final, "clamped," values. Calculations based on this concept, using the Hodgkin Huxley m-process as an example, are shown to lead to gating currents whose shapes are similar to those observed experimentally. One possible interpretation in terms of membrane structure is proposed.