Gerhard Schmid, Igor Goychuk and Peter Hänggi
Channel noise in excitable membranes
Single-channel recordings demonstrate that the switching of ion channels between open and closed configurations is a stochastic process. Moreover, the random switching of voltage-gated channels is connected with movement of charge within the cell membrane. These properties of channel gating affect the excitability of cell membrane patches. We investigate the influence of gating charge effects on the channel noise-induced spontaneous spiking activity of excitable membrane patches within a stochastic Hodgkin-Huxley modeling. Our study revealed that while the deterministic modeling with gating charge effects does not differ dramatically from the original Hodgkin-Huxley model for the standard set of parameters, the corresponding stochastic model which takes into account the channel noise -- i.e. the fluctuations of the number of open ion channels -- does behave very differently for intermediate-to-large membrane patch sizes. A main finding is that spontaneous spiking activity becomes drastically reduced.