Effect of P2Y₁ and P2Y₁₂ receptor antagonists or GIRK channel blockers on 2MeSADP-induced cPLA₂ phosphorylation. Washed and aspirin-treated human platelets were stimulated with 2MeSADP (100 nM) in the presence of fibrinogen (1 mg/mL) for various time points at 37°C (A), or for 60 seconds at 37°C, in the presence of MRS2179 (100 μM) or AR-C69931MX (100 nM) (B), and SCH23390 (10 μM), U50488H (10 μM), or SKF38393 (10 μM) (C). The reaction was stopped using 3X sample loading buffer (with DTT). The lysates were subjected to Western blotting analysis and probed with phospho-cPLA₂ (Ser505) and PKCδ (lane loading control).