I. Thromboxane (TXA) is made by platelets in response to injury.
- Thromboxane stimulates platelet aggregation
- Thromboxane stimulates vasoconstriction
II. Prostacyclin (PGI) is made by endothelial cells in response to blood flow.
- Prostacyclin inhibits platelet aggregation
- Prostacyclin stimulates vasodilation
III. COX-inhibitors affect blood clotting.
- Low doses of aspirin inhibit thromboxane production thereby decreaseing blood clotting
- COX-2 inhibitors such as the drug Celebrex inhibit prostacyclin production, thereby increasing blood clotting
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