ATP-mimetics derived from 2 '(3 ')-C-methyladenosine as human P2Y2 agonists

Background. To investigate the effect of conformational factors of the ribose-modified moiety in ATP mimetics, such as in 2'(3')-C-methyl-ATP, on the agonist activity at metabotropic P2Y2 receptor. Methods. The 2'(3')-C-methyl-ATP were synthesized and assayed for capacity to promote P2Y2 receptor-mediated activation of phospholipase C at recombinant human receptor expressed in astrocytoma cells. Agonist potency of the nucleotides was calculated using a four-parameter logistic equation and the GraphPad software package. Results. In vitro pharmacological data for 2'(3')-C-methyl-ATP (compounds 1 and 2, respectively) demonstrated that both ATP derivatives interact with the hP2Y2 receptor and behave as agonists. Nucleotide 2, which has a South conformation, resulted more potent than compound 1, which has the furanose ring in the N-puckered conformation (EC50 values: 1.29 and 11.9 microM, respectively). Conclusion. The effect of modifications at the ribose moiety of ATP, such as in 2'(3')-C-methyl-ATP on hP2Y2 receptor was evaluated. The potency of 3'-C-methyl-ATP, which has a South conformation, was higher than that of N-puckered 2'-C-methyl analogue. This is a surprising result because of the Northern conformational preference of hP2Y2 receptor detected by ring-constrained methanocarba analogues of ATP.