The intercellular communication mediated by gap junction channels is important for the normal development and function of many tissues. Reconstitution into planar artificial membranes can render channels accessible for detailed study, but identification of a channel in a bilayer as "junctional" is problematic. This chapter reviews the work to incorporate and identify channels formed of connexin32 in artificial membranes, and to study their properties. Gap junction channels are important in key areas of physiology and development. Gap junction channels in most tissues are composed of members of a family of homologous proteins called "connexins", which have been identified by cDNA cloning. To identify the specific junctional protein responsible for the sucrose permeability, the proteins in the unfractionated vesicles and in each transport-selected population of vesicles were analyzed by immunoblotting using a monoclonal antibody against connexin32 and by total protein visualization on blots using colloidal gold.