Clopidogrel inhibit platelet aggregation by?

ANSWER: (C) Inhibits ADPREF: Goodman and Gillmans 11TH ed, Page 972TICLOPIDINE The agonists of purinergic receptors are extracellular nucleotides. Platelets contain two purinergic receptors, P2Y1 and P2Y12; both are GPCRs for ADR The ADP-activated platelet P2Y1 receptor couples to the Gq-PLC-IP3-Ca2+ pathway and induces a shape change and aggregation. Activation of the P2Y12 receptor by ADP couples via Gi to inhibit adenylyl cyclase, resulting in lower levels of cyclic AMP and thereby less cyclic AMP-dependent inhibition of platelet activation. Apparently; both receptors must be stimulated for platelet activation, and inhibition of either receptor is sufficient to block platelet activation. Ticlopidine (TICLID) is a thieno pyridine that inhibits the P2Y12 receptor.CLOPIDOGREL The thieno pyridine dopidogrel (PLAVIX) is closely related to ticlopidine and appears to have a slightly more favorable toxicity profile with less frequent thrombocytopenia and leukopenia, although TTP has been reportedABCIXIMAB Abciximab (REOPRO) is the Fab fragment of a humanized monoclonal antibody directed against the IIa3h receptor.ASPIRIN: In platelets, the major cyclooxygenase product is thromboxane A2, a labile inducer of platelet aggregation and a potent vasoconstrictor. Aspirin blocks production of thromboxane A2 by acetylating a Ser residue near the active site of platelet cyclooxygenase (COX-1).