. Author manuscript; available in PMC: 2022 Jul 6.

Published in final edited form as: Drug Dev Res. 2003 Apr;58(4):330–339. doi: 10.1002/ddr.10168

TABLE 2.

Affinity and Efficacy of Adenosine Derivatives in CHO Cells Expressing hA₃AR

Derivative	Ki (nM)^a	EC₅₀(nM)^a	Efficacy_max^c
Riboside
CI-IB-MECA	2.8	1.9	100%
(N)-Methanocarba
MRS 1743	9.2	0.70^b	13%^b
MRS 1760	1.9	0.67^b	3%^b
MRS 1898	1.9	2.1	100%

K_i values refer to inhibition of the binding of [¹²⁵I]I-AB-MECA and EC₅₀ refers to inhibition of cyclic AMP production, unless noted.

In a functional assay based on guanine nucleotide binding [Jacobson et al., 2000], the efficacy of MRS 1743 and MRS 1760 was determined to be 45% and 22%, respectively.

cAMP effects.