P2X Receptor

P2X receptors are membrane ion channels preferably permeable to sodium, potassium and calcium that open within milliseconds of the binding of ATP. Each P2X receptor subunit had two membrane-spanning domains (TM1 and TM2), with intracellular N- and C-terminus, and that most of the protein was located as a large ectodomain. The P2X receptor genes contain 10–12 introns and are found on five chromosomes. The genes for P2X1 and PX5 receptors, and for P2X4 and P2X7 receptors, are adjacent: this presumably reflects relatively recent duplication. P2X receptors have a widespread tissue distribution. On some smooth muscle cells, P2X receptors mediate the fast excitatory junction potential that leads to depolarization and contraction.
In the central nervous system, activation of P2X receptors allows calcium to enter neurons and this can evoke slower neuromodulatory responses such as the trafficking of receptors for the neurotransmitter glutamate. In primary afferent nerves, P2X receptors are critical for the initiation of action potentials when they respond to ATP released from sensory cells such as taste buds, chemoreceptors or urothelium. In immune cells, activation of P2X receptors triggers the release of pro-inflammatory cytokines such as interleukin 1β. The development of selective blockers of different P2X receptors has led to clinical trials of their effectiveness in the management of cough, pain, inflammation and certain neurodegenerative diseases.


1.North RA. Philos Trans R Soc Lond B Biol Sci. 2016;371(1700):20150427.