Pharmacological characterization of the human P2Y11 receptor

Abstract

1. The human P2Y11 receptor is coupled to both the phosphoinositide and the cyclic AMP pathways. A pharmacological characterization of the recombinant human P2Y11 receptor has been conducted following stable expression in two different cell lines: the 1321N1 astrocytoma cells for inositol trisphosphate measurements and the CHO-K1 cells for cyclic AMP assays. The rank order of potency of a series of nucleotides was almost identical for the two pathways: ATPγS ≃ BzATP > dATP > ATP > ADPβS > 2MeSATP. 2. ADPβS, AMPαS and A3P5PS behaved as partial agonists of the human P2Y11 receptor. At high concentrations, these three nucleotides were able to partially inhibit the ATP response. 3. Suramin was a more potent antagonist than reactive blue 2, whereas pyridoxal-phosphate-6-azophenyl-2',4'-disulphonic acid was completely inactive. The P2Y11 receptor proved to be sensitive to suramin in a competitive way with an apparent K(i) value of 0.82 ± 0.07 μM. 4. The ATP derivative AR-C67085 (2-propylthio-β, γ-dichloromethylene-D-ATP), a potent inhibitor of ADP-induced platelet aggregation, was the most potent agonist of the P2Y11 receptor, among the various nucleotides tested. 5. The pharmacological profile of the recombinant human P2Y11 receptor is closely similar to that of the cyclic AMP-coupled P2 receptor recently described in HL-60 cells, suggesting that it is the same receptor.