P2X purinoceptor 7 is a protein that in humans is encoded by the P2RX7 gene. The product of this gene belongs to the family of purinoceptors for ATP. Multiple alternatively spliced variants which would encode different isoforms have been identified although some fit nonsense-mediated decay criteria. The receptor is found in the central and peripheral nervous systems, in microglia, in macrophages, in uterine endometrium, and in the retina. The P2X7 receptor also serves as a pattern recognition receptor for extracellular ATP-mediated apoptotic cell death, regulation of receptor trafficking, mast cell degranulation, and inflammation. P2X7 receptors respond to BzATP more readily than ATP. ADP and AMP are weak agonists of P2X7 receptors, but a brief exposure to ATP can increase their effectiveness. Glutathione has been proposed to act as a P2X7 receptor agonist when present at milimolar levels, inducing calcium transients and GABA release from retinal cells. The P2X7 receptor current can be blocked by zinc, calcium, magnesium, and copper.