ABSTRACT
This chapter presents an experiment which carried out on cell pairs isolated from adult rat and guinea pig ventricles by means of an enzymatic procedure. It illustrates an example of such a preparation. Cell pairs obtained in this manner represent incompletely disintegrated pieces of tissue. The enzymes digest the intercellular cement; however, they do not cleave gap junction channels into hemichannels. The electrical properties of the gap junction membrane and gap junction channels were determined using a double voltage-clamp method. Application of these methods in conjunction with a double voltage-clamp approach rendered it feasible to explore the functional aspects of gap junctions in isolated cell pairs. Hence, for the first time it became possible to elucidate the basic electrical properties of gap junction membranes and gap junction channels. In an isolated cell pair, the gap junction is not in direct contact with the patch pipette. This causes problems in determining the electrical properties of single gap junction channels.
