Theoretical approach to ion channel dynamics

Three theoretical aspects of single-channel current analysis are presented: (1) A stochastic theory of a stationary multichannel system is developed, based on the so-called basic theorem. The dwell-time distribution of every type of period between successive open or shut transitions and other stochastic properties is obtained. Analysis and computer-simulation errors are estimated. (2) Two properties satisfied by channels in equilibrium are shown: (i) Any of the probability density functions of dwell times are expressed by the sum of decaying exponentials with positive coefficients. (ii) The state transition time course from state I to J is proportional to that from J to I. (3) A steady/equilibrium approximation is presented that simplifies a complex channel model containing both short-lifetime and long-lifetime states and gives a reduced model containing only long-lifetime states.<>