Ionic Channels in Cells and Model Systems

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.

Contenu
I. Methodologies.- 1 Kinetic Models and Channel Fluctuations.- 2 Single-Channel Currents and Postsynaptic Drug Actions.- 3 Voltage-Dependent Gating: Gating Current Measurement and Interpretation.- 4 Characterizing the Electrical Behavior of an Open Channel via the Energy Profile for Ion Permeation: A Prototype Using a Fluctuating Barrier Model for the Acetylcholine Receptor Channel.- 5 The Use of Specific Ligands to Study Sodium Channels in Muscle.- 6 Isolation of Muscle Membranes Containing Functional Ionic Channels.- 7 Methodologies to Study Channel-Mediated Ion Fluxes in Membrane Vesicles.- 8 Optical Studies on Ionic Channels in Intact Vertebrate Nerve Terminals.- 9 Optical Detection of ATP Release from Stimulated Endocrine Cells: A Universal Marker of Exocytotic Secretion of Hormones.- II. Channels in Biological Membranes.- 10 Mechanotransducing Ion Channels.- 11 Ionic Channels in Plant Protoplasts.- 12 Channels in Kidney Epithelial Cells.- 13 Channels in Photoreceptors.- 14 Inactivation of Calcium Currents in Muscle Fibers from Balanus.- 15 Electrophysiological Studies in Endocrine Cells.- III. Ionic Channel Reconstitution.- 16 Ion Channel Reconstitution: Why Bother?.- 17 From Brain to Bilayer: Sodium Channels from Rat Neurons Incorporated into Planar Lipid Membranes.- 18 Ionic Channels in the Plasma Membrane of Sea Urchin Sperm.- 19 Characterization of Large-Unitary-Conductance Calcium-Activated Potassium Channels in Planar Lipid Bilayers.- IV. Ionic Channel Modulation.- 20 Metabolic Regulation of Ion Channels.- 21 The Cell-to-Cell Membrane Channel: Its Regulation by Cellular Phosphorylation.- 22 The ?-Cell Bursting Pattern and Intracellular Calcium.- 23 Neurotrophic Effects of in Vitro Innervation of Cultured Muscle Cells. Modulation of Ca2+-Activated K+Conductances.- V. Ionic Channel Structure, Functions, and Models.- 24 Correlation of the Molecular Structure with Functional Properties of the Acetylcholine Receptor Protein.- 25 Amiloride-Sensitive Epithelial Sodium Channels.- 26 A Channel Model for Development of the Fertilization Membrane in Sea Urchin Eggs.