The Paul laboratory is exploring the function of gap junctions in the nervous system. Gap junctions are collections of intercellular channels allowing direct movement of small molecules between cells. Such channels provide a mechanism for propagation of excitation among neurons, where they constitute electrical synapses, and also provide a route of signal transduction essential for glial cell functioning in both central and peripheral nervous systems. However, since there are no pharmacologic inhibitors of intercellular channels, precisely defining the roles of intercellular communication is a major challenge. To that end, we have produced a series of alterations in the >20 related genes encoding connexins (Cx), the intercellular channel forming proteins.