This book is based on a series of lectures for a course on ionic
channels held in Santiago, Chile, on November 17-20, 1984. It is
intended as a tutorial guide on the properties, function, modulation,
and reconstitution of ionic channels, and it should be accessible to
graduate students taking their first steps in this field. In the
presentation there has been a deliberate emphasis on the spe- cific
methodologies used toward the understanding of the workings and function
of channels. Thus, in the first section, we learn to "read" single-
channel records: how to interpret them in the theoretical frame of
kinetic models, which information can be extracted from gating currents
in re- lation to the closing and opening processes, and how ion
transport through an open channel can be explained in terms of
fluctuating energy barriers. The importance of assessing unequivocally
the origin and purity of mem- brane preparations and the use of membrane
vesicles and optical tech- niques in the stUGY of ionic channels are
also discussed in this section. The patch-clamp technique has made it
possible to study ion channels in a variety of different cells and
tissues not amenable to more conven- tional electrophysiological
methods. The second section, therefore, deals with the use of this
technique in the characterization of ionic channels in different types
of cells, ranging from plant protoplasts to photoreceptors.