This volume is a collection of papers designed to increase awareness and utilization of fluctuation theory for the description of ionic events at the membrane. The papers are revised and updated versions of presentations made at a workshop entitled Noise Measurements as a Probe of Ionic Conductance.
As a result of discussions held at that meeting, the participants were asked to provide selected chapters designed to provide detailed descriptions of the theory and its application to a number of membrane channels. Fluctuation theory was developed initially to explain statistical fluctuations of ordinary physical quantities such as random collisions between gas molecules and walls. As knowledge of ionic pores has advanced, it has become apparent that randomized fluctuations could be utilized to characterize pore behavior in excitable and epithelial membranes. Because of the increased awareness of the applicability of fluctuation theory, the workshop participants were invited to contribute papers to this volume to provide them with an opportunity to teach others the essentials of noise measurements. The emphasis of this volume is on the practical steps which must be followed to make and interpret measurements of noise, both noise produced by natural fluctuatjons of the transport system, and noise which is the response to an applied stochastic signal. This collection of papers is meant to emphasize practical limitations as well as practical and theoretical advantages of such measurements.