Discovery of P2X 7 receptor‐selective antagonists offers new insights into P2X 7 receptor function and indicates a role in chronic pain states

ATP‐sensitive P2X 7 receptors are localized on cells of immunological origin including peripheral macrophages and glial cells in the CNS. Activation of P2X 7 receptors leads to rapid changes in intracellular calcium concentrations, release of the proinflammatory cytokine interleukin‐1β and following prolonged agonist exposure, the formation of cytolytic pores in plasma membranes. Both the localization and functional consequences of P2X 7 receptor activation indicate a role in inflammatory processes. The phenotype of P2X 7 receptor gene‐disrupted mice also indicates that P2X 7 receptor activation contributes to ongoing inflammation. More recently, P2X 7 receptor knockout data has also suggested a specific role in inflammatory and neuropathic pain states. The recent discovery of potent and highly selective antagonists for P2X 7 receptors has helped to further clarify P2X receptor pharmacology, expanded understanding of P2X 7 receptor signaling, and offers new evidence that P2X 7 receptors play a specific role in nociceptive signaling in chronic pain states. In this review, we incorporate the recent discoveries of novel P2X 7 receptor‐selective antagonists with a brief update on P2X 7 receptor pharmacology and its therapeutic potential. British Journal of Pharmacology (2007) 151 , 571–579; doi: 10.1038/sj.bjp.0707265