This core is responsible for the development, characterization and application of antibodies, primarily against connexins, to studies of gap junctions in their various roles. We currently have a battery of polyclonal and, for some, monoclonal anti-peptide antibodies corresponding to regions of rat Cx32, Cx26 and Cx43 as well as monoclonal and polyclonal antibodies generated to purified Cx32. Polyclonal anti-peptide antibodies have been developed to Xenopus Cx38, as well. Antibodies to connexins recently identified as existing in neural cell types (i.e. Cx40 in astrocytes and Cx46 in Schwann cells) will also be developed as will antibodies to other connexins should they be found to exist by us or others. Procedures have been optimized for a variety of techniques including Western blots and immunoprecipitation. In conjunction with the cytology core (Core B), these antibodies are also used for immunocytology by light and electron microscopy.