P2X1-initiated p38 signalling enhances thromboxane A2-induced platelet secretion and aggregation

Summary ATP released by activated platelets can serve as a positive feedback machinery to amplify platelet responses by activating P2X 1 receptors. It has, however, not been defined how P2X 1 activities influence thromboxane A 2 (TXA 2 )-stimulated platelet functional responses. Our aim was to elaborate the molecular mechanisms of P2X 1 engagements in TXA 2 -induced platelet secretion and aggregation. P2X 1 inhibition by 1 µM NF449 inhibited platelet P-selectin expression induced by a low concentration of the TXA 2 analogue U46619 (0.3 µM) (32.0 ± 2.0% vs 43.4 ± 3.0%; n=5; p