Table 1.

Tissue distribution and cellular localization of P2X.

Receptor	Location
P2X1	Smooth muscle: heart, bladder, vas deferens, and arteries (vascular smooth muscle) Blood cells: platelets, mast cells, and lymphocytes Nervous system: astrocytes and spinal cord
P2X2	Nervous system: retina, carotid body, brain, enteric nervous system, cochlea, autonomic neurons, and sensory neurons
P2X3	Sensory nervous system, trigeminal ganglia, pelvic nerve, dorsal root ganglia, and taste buds
P2X4	Sensory nervous system, olfactory bulb, hypothalamus, cerebellum, GABAergic neurons of the striatum and substantia nigra, and retinal ganglia
P2X5	Immune system: T cells and B cells
P2X6	B cells and heart
P2X7	Ubiquitous: brain (cerebral cortex, piriform cortex, ependymal cells, microglia, lateral septal nucleus, oligodendrocytes, hippocampal pyramidal cells, and other neurons), retina, olfactory nucleus, salivary glands (parotid and submandibular glands), lacrimal glands, Schwann cells, blood cells (erythrocytes, monocytes, macrophages, granulocytes, mast cells, and B and T lymphocytes), thymus, tonsils, bone marrow, bone (osteoblasts and osteoclasts), fibroblasts, dendritic cells, keratinocytes, lung, prostate, testis, heart, liver, skeletal muscle, pancreas, and kidney

Note: Reference [20].