Table 4.
Characterization of P2X receptors [Modified and updated from Burnstock (2003), with permission]
| Receptor | Main distribution | Agonists | Antagonists |
|---|---|---|---|
| P2X1 | Smooth muscle, platelets, cerebellum, dorsal horn spinal neurones | L-βγ-meATP ≥α,β-meATP = ATP = 2-MeSATP | TNP-ATP, IP5I, NF023, NF449 |
| PAPET-ATP (rapid desensitization) | RO1, RO 0437626, NF279, MRS2159 | ||
| P2X2 | Smooth muscle, CNS, retina, chromaffin cells, autonomic and sensory ganglia | ATP ≥ ATPγS ≥ 2-MeSATP >> α,β-meATP, β,γ-CF2ATP (pH + zinc sensitive) | Suramin, RB2, NF770, isoPPADS, PSB-1011, NF778, aminoglycoside |
| P2X3 | Sensory neurones, NTS, some sympathetic neurones | 2-MeSATP ≥ ATP ≥α,β-meATP = Ap4A, PAPET-ATP (rapid desensitization) | TNP-ATP, isoPPADS |
| A317491, NF110, RO4, RN-1838, spinorphin, AF353 | |||
| P2X4 | CNS, testis, colon | ATP > α,β-meATP, CTP | TNP-ATP and BBG (weak), BBG, Paroxetine, 5-BDBD, CORM 2, phenolphthalein |
| Ivermectin (potentiates) | |||
| P2X5 | Proliferating cells in skin, gut, bladder, thymus, spinal cord | ATPγS | Suramin, PPADS, BBG |
| Ap4A | |||
| GTP | |||
| P2X6 | CNS, motor neurones in spinal cord | Does not function as homomultimer | – |
| P2X7 | Apoptotic cells in immune cells, pancreas, skin, etc. | BzATP > ATP ≥ 2-MeSATP > α,β-meATP | KN62, KN04, MRS2427, BBG, o-ATP, Decavanadate, A-804598, RN-6189, AZD-9056, AZ10606120, A740003, A-438079, GSK-1370319 |
5-BDBD, 5-(3-bromophenyl)-1,3-dihydro-2H-benzofuro[3,2-e]-1,4-diazepine-2-one; BBG, brilliant blue G; NTS, nucleus tractus solitarii; PPADS, pyridoxalphosphate-6-azophenyl-2′,5′-disulfonic acid; TNP-ATP, 2′(3′)-O-(2,4,6-trinitrophenyl) ATP.