Patch-Clamp Techniques and Analysis

Abstract

Patch-clamp technique revolutionized electrophysiology by revealing the activity of individual molecular ion channels involved in electrical signaling in excitable cells. This chapter focuses on the technique and its application in studies of single channels or unitary conductance. It describes different variations of the patch-clamp technique, that is, cell-attached, inside-out, and outside-out, and its modifications as used in the study of single-channel currents. It also explains the more commonly used application of whole-cell voltage clamp and its variation, and the perforated-patch methods that examine macroscopic currents. Although whole-cell recording provides information of the gating properties and kinetic characteristics of the channel protein, single-channel recordings allow a more detailed evaluation of the kinetic properties of the channel protein. The different variations or modes of patch recordings permit the experimenter to alter the environment and examine the gating and behavior of a single-channel protein. Another variation of the patch-clamp technique, the whole-cell tight-seal voltage clamp, proves to be particularly useful for the study of macroscopic currents. As this method is applicable to small cells, it opens up a new vista for experimentation, allowing experimenters to examine currents in cells that were previously not accessible to recording with conventional sharp-tipped electrodes.