Heterologous Expression Systems and Analyses of Ion Channels

This chapter describes practical techniques for electrophysiological experiments in the heterologous expression systems using mammalian cell cultures and Xenopus laevis oocytes. These two experimental systems are the most commonly used for expression of ion channels and transporters, contributing to numerous discoveries of their function and molecular properties. When planning an experiment, researchers need to determine whether either system is appropriate for use. It is crucial to understand the advantages and disadvantages of each system. The practical techniques discussed here include preparation of cells, heterologous expression of ion channel and other proteins, and the electrophysiological techniques available for recording from these systems. Also, we show the applications of these systems to analyses of K⁺ channels.