MRS 2279 is a selective, high affinity competitive antagonist of the P2Y1 receptor (Ki = 2.5 nM; IC50 = 51.6 nM). Fails to block nucleotide signaling at most other P2Y receptors (P2Y2, P2Y4, P2Y6, P2Y11 and P2Y12) and potently inhibits ADP-induced aggregation of human blood platelets in vitro (pKB = 8.05).
