Whole-Cell and Microelectrode Voltage Clamp

As other chapters in this book demonstrate, intra- and extracellular recording provide considerable information about the electrical behavior of cells. However, as Hodgkin and Huxley (1952) taught us long ago, analysis of the mechanisms that generate electrical activity is far easier with voltage clamp. If the behavior of ion channels depends on voltage, the first step in studying such channels is to control the voltage. Under voltage clamp, the kinetic behavior of a channel (or of a macroscopic assemblage of channels) is at its simplest. Without voltage clamp, there is a complex interaction between channel gating and membrane potential. When channels open, current through them affects the membrane potential, which in turn makes channels open (or close), affecting the membrane potential....