Nonlinear drift-diffusion model of gating in K and nACh ion channels

The configuration of a sensor regulates the transition between the closed and open states of both voltage and ligand gated channels. The closed state dwell-time distribution fc(t)fc(t) derived from a Fokker–Planck equation with a nonlinear diffusion coefficient is in good agreement with experimental data and can account for the power law approximation to fc(t)fc(t) for a delayed rectifier K channel and a nicotinic acetylcholine (nACh) ion channel. The solution of a master equation which approximates the Fokker–Planck equation provides a better description of the small time behaviour of the dwell-time distribution and can account for the empirical rate-amplitude correlation for these ion channels.