Cell coupling in the retina: patterns and purpose.

Abstract

Gap junction channels (electrical synapses) are a major component of the central nervous system mediating both electrical and metabolic coupling between neurons and glia. Their roles are as diverse as the cell types in which they are expressed and only some of these are reviewed here. In the adult the plastic nature of the gap junction channel allows for changes in the writing of the retinal circuitry that optimize visual processing to suit ambient lighting conditions. Gap junctional communication has been proposed to play a key role in embryonic development in general and in particular during the development of the retina where its roles may include control of neurogenesis, cell specification, synaptogenesis, and the synchronization of the spontaneous electrical activity required for the sharpening of central visual projections. Here we review gap junctional coupling within the retina and present data correlating gap junction expression with development events in the chick retina.