Thromboxane A2 (TXA2)

Thromboxane A2 (TXA2) is a biologically active lipid molecule classified as an eicosanoid and specifically as a thromboxane. It is produced primarily by activated platelets during hemostasis and plays a central role in promoting platelet aggregation, vasoconstriction, and blood clot formation. TXA2 acts locally at the site of synthesis due to its short half-life and instability. It exerts its effects by binding to the thromboxane-prostanoid receptor (TP), a G protein-coupled receptor.

Aspirin inhibits cyclooxygenases, reducing precursor availability for TXA2 synthesis. Thromboxane synthase inhibitors block conversion from PGH2 to TXA2. TP receptor antagonists prevent downstream signaling.