Table 2.

K _i values of standard AR ligands at A₁ adenosine receptors

	A1 Adenosine receptor affinity
	Human	Rat	Mouse
Agonists	K i ± SEM (nM) vs. [3H]CCPAa
NECA	14 [49]	5.1 [54]	2.49 ± 0.15
CADO	1.39 [3]	6.7 [54]	2.79 ± 0.04
CCPA	0.83 [49]	7.43 [55]	0.269 ± 0.064
R-PIA	2.04 [49]	1.2 [56]	0.587 ± 0.070
CGS-21680	289 [49]	1800 [56]	961 ± 108
BAY60-6583	387 ± 70	514 ± 57	351 ± 19
IB-MECA	51 [57]	54 [58]	16.4 ± 1.7
CI-IB-MECA	220 [57] 115 [3]	820 [59]	46.2 ± 3.6
Antagonists	K i ± SEM (nM) vs. [3H]DPCPXa
Caffeine	44,900 [60] 10,700 [61]	18,800 [46] 41,000 [62]	50,700 ± 5800
Theophylline	6200 [46]	8500 [46]	14,200 ± 6000
CGS-15943	3.5 [56]	6.4 [56]	1.15 ± 0.16
DPCPX	3.0 [63]	0.50 [64]	0.413 ± 0.064
PSB-36	0.7 [5]	0.124 [60]	1.58 ± 0.18
PSB-63	90.6 [5]	16.9 [5]	2370 ± 475
CPT	23.7 ± 2.4	24 [5] 6.3 [65]	7.41 ± 0.41
Istradefylline	841 [5]	230 [46] 150 [66]	438 ± 93
ZM-241385	774 [56]	684 ± 63	236 ± 36
Preladenant	>1000 [56]	>1000	462 ± 118
PSB-601	2070 [44]	260 [44]	123 ± 25
PSB-603	>10,000 [46]	>10,000 [46]	42.4 ± 4.2
PSB-1115	>10,000 [46]	2200 [45]	591 ± 63
PSB-0788	2240 [46]	386 [46]	118 ± 21
MRS-1754	403 [67]	16.8 [67]	1.45 ± 0.42
MRS-1523	>10,000 [56]	15,600 [68]	>10,000

^aData are means ± SEM of three independent assays performed in duplicates. The values without SEM are taken from the literature as indicated