. 2010 Sep 10;1(9):516–520. doi: 10.1021/ml1001823

Table 1. Binding Affinities of Known A₃ AR Antagonist 3 and Truncated 2- and 8-Substituted 4′-Thioadenosine Derivatives 4a−d at Three Subtypes of hARs.

	affinity^a
compounds	hA₁ (% inhibition)	hA_2A (% inhibition)	hA₃ (K_i, nM)
3	37.9	17.7	1.66 ± 0.90
4a	38.9 ± 9.9	97.2 ± 4.1	11.8 ± 1.3
4b	16.2 ± 8.4	95.9 ± 8.7	13.2 ± 0.8
4c	49.3 ± 4.9	46.5 ± 4.3	20.0 ± 4.0
4d	3.7 ± 2.9	22.8 ± 6.4	259 ± 10

All binding experiments were performed using adherent mammalian cells stably transfected with cDNA encoding the appropriate hAR (A₁ AR and A₃ AR in CHO cells and A_2A AR in HEK-293 cells). Binding was carried out using 1 nM [³H]CCPA, 10 nM [³H]CGS21680, or 0.5 nM [¹²⁵I]I-AB-MECA as radioligands for A₁, A_2A, and A₃ ARs, respectively. Values are expressed as means ± SEMs, n = 3−4 (outliers eliminated) and normalized against a nonspecific binder, 5′-N-ethylcarboxamidoadenosine (NECA, 10 μM). Values expressed as a percentage refer to the percent inhibition of specific radioligand binding at 10 μM, with nonspecific binding defined using 10 μM NECA.

Table 1. Binding Affinities of Known A3 AR Antagonist 3 and Truncated 2- and 8-Substituted 4′-Thioadenosine Derivatives 4a−d at Three Subtypes of hARs.

Table 1. Binding Affinities of Known A₃ AR Antagonist 3 and Truncated 2- and 8-Substituted 4′-Thioadenosine Derivatives 4a−d at Three Subtypes of hARs.