Which component is directly reduced by aspirin that leads to decreased platelet aggregation?

• A. Thromboxane A2 production
• B. Hemoglobin synthesis
• C. Dopamine release
• D. Calcium deposition

Answer: (A)

Aspirin decreases the ability of platelets to clump together by irreversibly inhibiting cyclooxygenase-1 in platelets, which blocks the production of thromboxane A2. Thromboxane A2 is a powerful promoter of platelet activation and aggregation and also causes vasoconstriction. Since platelets lack a nucleus, they can’t synthesize new COX-1, so the drop in thromboxane A2 persists until new platelets are formed. The other options don’t fit because they aren’t directly involved in the platelet aggregation pathway: hemoglobin synthesis is about red blood cells, dopamine release isn’t a key mediator of platelet function, and calcium deposition relates to bone and mineral metabolism.