Purinergic receptor P2X (P2X receptor)

Purinergic receptor P2X is a family of ligand-gated ion channels activated by extracellular ATP, composed of three subunits forming a trimeric structure embedded in the plasma membrane. These non-selective cation channels permit flux of Na\(^+\), K\(^+\), and Ca\(^{2+}\) upon ATP binding, mediating rapid excitatory postsynaptic currents as well as diverse physiological responses including nociception, smooth muscle contraction, platelet aggregation, immune cell activation, and apoptosis. P2X receptors are widely expressed in neuronal and non-neuronal tissues, often co-assembling in different subunit combinations to generate functional diversity. They play key roles in inflammation, pain pathways, immune signaling, and potentially in neurodegeneration, cancer, and cardiovascular pathophysiology. Multiple drug classes act as antagonists or modulators of P2X receptor subtypes, and clinical interest has focused on antagonists for pain and chronic cough, with gefapixant representing a recent approval targeting P2X3. The structural and pharmacological complexity, along with crucial physiological functions, generate both therapeutic promise and safety challenges for this receptor family.

Other names

ATP-gated P2X receptorP2X purinoreceptorP2X ion channelATP-gated cation channelP2X ligand-gated ion channel

Competitive antagonism at the ATP-binding site (e.g., TNP-ATP, A-317491, gefapixant); Non-selective inhibition of multiple subtypes (suramin, PPADS); Allosteric modulation (ivermectin enhances P2X4, Zn2+); Irreversible inhibition via lysine modification (oxidized ATP, P2X7)