In this volume of Methods in Pharmacology we have brought together experts in the field of ion channels to provide the reader with an in-depth view of current biochemical and electrophysiological methods. The focus is on cation-selective ion channels (voltage controlled Of ligand controlled) that are of special pharmacological interest. The con- tents are divided into three sections that exemplify {I) molecular and biochemical characterization of ion channels, (II) functional analysis of ion channels (after recon- stitution or expression, or in cells), and (III) specific methods and tools. The editors thank the contributors for their cooperation in assembling this volume. We are convinced that the reader will enjoy the chapters, written by leading scientists in their respective disciplines, as much as we did. Hartmut Glossmann Jarg Striessnig Innsbruck, Austria vii Contents I MOLECULAR AND BIOCHEMICAL CHARACTERIZA nON OF ION CHANNELS 1 Purification and Pharmacological Analysis of the Omega-Conotoxin 3 GVIA Receptor from Rat Brain Maureen W McEnery 2 Molecular Characterization of the Charybdotoxin-Sensitive, 41 High-Conductance, Calcium-Activated Potassium Channel Margarita Garda-Calvo, Gregory J. Kaczorowski, and Maria L. Garda 3 Characterization of the Sulfonylurea-Sensitive ATP-Modulated 61 Potassium Channel Henri Bernardi and Michel Lazdunski II FUNCTIONAL ANALYSIS OF ION CHANNELS 4 Xenopus Oocytes as an Expression System for Ion Channels 79 Alan L. Goldin ix x Contents 5 Reconstitution of Muscle Calcium Channel Function in Bilayer 99 Membranes: From the First Steps to Results Dieter J. Pelzer, Terence F.