Connexins and information transfer through glia.

Abstract

In most vertebrate tissues, direct electrical and biochemical communication between groups of adjacent cells is mediated by intercellular channels which are present in gap junctions. A complete intercellular channel spans two plasma membranes and is formed by the alignment of two half-channels, termed connexons, that interact in the extracellular space to provide a relatively large hydrated pore between the cytoplasm of the coupled cells (White and Paul, 1999). Each connexon is an oligomer of structural subunit proteins, called connexins (Cx), which form a multigene family whose members are distinguished according to their predicted molecular mass in kDa. More than a dozen connexins have been characterized to date in mammals. Because most cells express multiple connexins, adjacent cells can assemble different types of connexons and contribute to the formation of either homotypic, heterotypic, or heteromeric channels (Fig. 1). In this chapter we will refer to connexin channels when reviewing the molecular properties of intercellular channels and to either coupling, gap junctional or intercellular communication when discussing the general aspects of cell-cell communication. Clearly, these terms are functionally equivalent. We have selected only a few aspects of connexin properties and function in glial cells of the central nervous system (CNS) and peripheral nervous system (PNS), with emphasis on the issues that are likely to shape this area of research in the near future.KeywordsGlial CellSchwann CellIntercellular CommunicationIntercellular ChannelConnexin GeneThese keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.