Classification of adenosine/P1 receptors
| A1 | A2A | A2B | A3 | |
|---|---|---|---|---|
| G protein-coupling | Gi/o | GS | GSGq | Gi Gq |
| Effects | ↓cAMP | ↑cAMP | ↑cAMP | ↓cAMP |
| ↑IP3 | ↑IP3 | ↑IP3 | ||
| ↑K+ | ||||
| ↓Ca2+ | ||||
| Selective agonists | CPA, CCPA, CHA, R-PIA | CGS21680, HE-NECA, APEC, CV 1808, DPMA, WRC-0470 | — | IB-MECA, 2Cl-IB-MECA |
| Selective antagonists | DPCPX, XAC, KW-3902, ENX, KFM 19, N 0861, FK 453, WRC 0571 | KF17837, ZM241385, CSC, SCH 58261 | — | I-ABOPX2-a, L-268605, L-249313, MRS 1067, MRS 1097 |
Abbreviations: APEC, 2-[(2-aminoethylamino)carbonylethylphenylethylamino]-5′-N-ethylcarboxamidoadenosine; CGS21680, 2-[p-(2-carbonyl-ethyl)-phenylethylamino]-5′-N-ethylcarboxamidoadenosine; CCPA, 2-chloro-CPA; CHA, N 6-cyclopentyladenosine; 2Cl-IB-MECA, 2-chloro-N6-(3-iodobenzyl)-5′-(N-methylcarbamoyl)adenosine; CPA, N6-cyclopentyladenosine; CSC, 8-(3-chlorostyry)caffeine; CV 1808, 2-phenylaminoadenosine; DPCPX, 1,3-dipropyl-8-cyclopentylxanthine; DPMA,N 6-[2(3,5-dimethoxyphenyl)-2-(2-methylphenyl)ethyl]-adenosine; ENX, 1,3-dipropyl-8-[2-(5,6-epoxy)norbornyl]xanthine; FK 453, (+)-(R)-[(E)-3-(2-phenylpyrazolo[1,5-α]pyridin-3-yl)acryloyl]-2-piperidine ethanol; HE-NECA, 2-hexyl-5′-N-ethylcarboxamidoadenosine; I-ABOPX, 3-(3-iodo-4-aminobenzyl)-8-(4-oxyacetate)phenyl-1-propylxanthine; IB-MECA, N6-(3-iodobenzyl)-5′-(N-methylcarbamoyl)adenosine; KF17837, 1,3-dipropyl-8-(3,4-dimethoxystyryl)-7-methylxanthine; KFM 19, [(±)-8-(3-oxocyclopentyl)-1,3-dipropylxanthine]; KW-3902, 8-noradamant-3-yl-1,3-dipropylxanthine; L-249313, 6-carboxymethyl-5,9-dihydro-9-methyl-2-phenyl-[1,2,4]-triazolo[5,1-a][2,7]naphthyridine; L-268605, 3-(4-methoxyphenyl)-5-amino-7-oxo-thiazolo[3,2]pyrimidine; MRS 1067, 3,6-dichloro-2′-isopropyloxy-4′-methylflavone; MRS 1097, 3,5-diethyl 2-methyl-6-phenyl-4-(trans-2-phenylvinyl)-1,4(R,S)-dihydropyridine-3,5-dicarboxylate; N 0861, 1,3-dipropyl-8-[2,(5,6-epoxy)norbornyl]xanthine;R-PIA, (R)N 6-phenylisopropyladenosine; SCH 58261, 5-amino-7-(2-phenylethyl)-2 (2-furyl)-pyrazolo[4,3-e]-1,2,4-triazolo[1,5-c]pyrimidine; WRC 0470, 2-cyclohexylmethylidenehydrazinoadenosine; WRC 0571, 8-(N-methylisopropyl)amino-N6-(5′-endohydroxy-endonorbornyl)-9-methyladenine; XAC, xanthine amine congener; ZM 241385, 4-(2-[7-amino-2-(2-furyl)]1,2,4-triazolo[2,3-a][1,3,5]triazin-5-ylamino]ethyl)phenol.
↵2-a High affinity (nM) at sheep and human, but not rat A3 adenosine receptors.