Single channel recording and gating function of ionic channels.

This review discusses several aspects of the kinetic analysis of the gating function of membrane channels, as carried out on single channel data obtained by the patch clamp method. In particular, the following three aspects of channel behavior are reviewed in some detail: 1) estimate of the number of states or conformations the channel can enter; 2) the lifetime of each state as a function of transmembrane voltage (voltage-gated channels), or of ligand concentration (ligand-gated channels); 3) estimates of the rates at which the transitions between the various states occur, and assessment of reaction mechanisms. An introductory description of conformational transitions of channel proteins is also provided.