Kinetic aspects of ion transport through neural membrane

The Hodgkin‐Huxley model for the nerve membrane action potential is reviewed. The model can be described in terms of channels and gates. That is, ions permeate the nerve membrane through narrow ion specific pores, or channels, which are modulated by a voltage dependent gating process. The Hodgkin‐Huxley model provides a detailed kinetic scheme for channel gating, but not for channel permeation. Radioactive tracer flux experiments suggest that permeation occurs via single file motion of ions through a channel. We have modeled this process as a random walk with internal states. The theory leads to expressions for one way fluxes which can be compared with experimental tracer flux data. Recent experiments on channel gating have indicated that the Hodgkin‐Huxley model of the gating process requires certain modifications. We present a class of modifications involving temporal memory of gating and interactions between gating particles of any single channel. Thses models can also be described in terms of random w...