Table 1.

Fluorescent ligand binding affinities^a at three AR subtypes

No	Compound	hA1, Ki (nM) or % inhib. at 1 µM	hA2A Ki (nM) or % inhib. at 1 µM	hA3 Ki (nM) or % inhib. at 1 µM
XAC 7 and its conjugates
7	XACb	8.3 ± 1.1	32.1 ± 5.9	38.3 ± 6.7
9	XAC-245b	35%	198 ± 33	220 ± 36
10	XAC245-AF488	19%	316 ± 24	40 ± 3%
11	XAC245-AF647	18%	37 ± 21%	41 ± 5%
12	XAC245-JF646c	53%	144 ± 24	495 ± 89
13	XAC245-JF549	29%	882 ± 215	36.9 ± 4.3%
14	XAC245-Sulfo-Cy7 (750 nm)d	20%	1290 ± 470	49.7 ± 11.8%
15	XAC245-Sulfo-Cy7.5 (778 nm)d	27%	1120 ± 310	30.8 ± 3.5%
16	XAC245-FNIR-Tag (765 nm)d	27%	956 ± 232	232 ± 53
CGS15943 8 and its conjugates
8	CGS15943e	3.5	1.2	35
5	MRS5449e	87 ± 24	73 ± 8	6.4 ± 2.5
17	Alkyne deriv.e	170 ± 40	51 ± 10	33.5 ± 10.1
19	CGS15943-3T6-Sulfo-Cy7c	53%	244	21.6 ± 4.0

^aDetermined with membranes of HEK293 cell expressing each receptor and using the following radioligands (final concentration in incubation medium), unless noted: A₁, [³H]DPCPX (0.7 nM); A_2A, [³H]CGS21680 (8.1 nM); A₃, [.¹²⁵I]I-AB-MECA (0.15 nM). Results are expressed as mean ± SEM from at least 3 independent experiments

^bA_2A and A₃ AR affinities reported in Gao et al. [13]. A₁AR affinity of XAC (using [³H]R-PIA) is from Kecskés et al. [46]

^c12, MRS7774; 19, MRS7535

^dExcitation wavelength

^eAR affinities reported in Kozma et al. [8]