The contribution of extracellular ATP to retinal function and potentiating retinal degenerations

Abstract

There are myriad retinal functions that are mediated by purines. P2X receptors, especially P2X7 receptors, are expressed by photoreceptors and inner retinal neurons and are capable of modulating the retinal “through” pathway. Beyond neurons, resident immune cells, called microglia, as well as glial cells, express a range of P2X and P2Y receptors. Of particular interest are the multiple roles that P2X7 receptors can play depending on the length and extent of exposure to ATP. In addition to the role of P2X7 as a ligand-gated ion channel, it can also mediate phagocytosis by binding to phosphatidylserine moieties on dying cells. However, when concentrations of ATP are high in the extracellular s..