This chapter reviews the localizations and physiological roles of connexins in neurons and glia of the central and peripheral nervous systems. Cx32 forms gap junctions in noncompact myelin in Schwann cells, which are thought to form a reflexive communication pathway connecting the outer and inner myelin layers. Cx29 is also expressed in myelinating Schwann cells, but does not appear to form gap...

Rapid spreading of the electrical impulse throughout the heart is essential for coordinated contraction and is mediated by electrical coupling of cardiomyocytes through gap junction channels composed of connexin40 (Cx40), connexin43 (Cx43) or connexin45 (Cx45). Each of these connexin proteins has a characteristic developmental and regional expression pattern in the heart. Alterations in this pa...

The normal function and survival of cells in the avascular lens is facilitated by intercellular communication through an extensive network of gap junctions formed predominantly by three connexins (Cx43, Cx46, and Cx50). In expression systems, these connexins can all induce hemichannel currents, but other lens proteins (e.g., pannexin1) can also induce similar currents. Hemichannel currents have...

Gap junctions provide one of the most common forms of intercellular communication. They are composed of membrane proteins that form a channel that is permeable to ions and small molecules, connecting the cytoplasm of adjacent cells. Gap junctions serve similar functions in all multicellular animals (Metazoa). Two unrelated protein families are involved in this function; connexins, which are fou...