P2X receptors are a family of seven (P2X1R-P2X7R) cation permeable ligand-gated ion channels (LGICs) that open in response to binding by the extracellular ligand, adenosine 5′-triphosphate (ATP). P2X receptors have a high permeability to Ca2+, Na+, and K+ and are expressed widely throughout the nervous, immune, cardiovascular, skeletal, gastrointestinal, respiratory, and endocrine systems.
P2X receptors are widely expressed in excitatory and non-excitatory cells, such as neuron, glia, platelet, epithelia and macrophage, and participate in many important physiological and pathological processes, including synaptic transmission, pain perception, inflammation, cardiovascular modulation, immunomodulation and tumorigenesis.