[Do glycoproteins IIb/IIIa participate in activation of human platelet s by low density lipoproteins?].

Low density lipoproteins (LDL) enhance the entry of Ca2+ and other bivalent cations via receptor-operated channels. The use of a synthetic peptide and antibodies blocking the glycoproteins IIb and IIIa interaction with ligands revealed that fibrinogen receptor antagonists prevent platelet aggregation without any effect on the ability of LDL to increase the cytoplasmic Ca2+ level. These data indicate that glycoproteins IIb-IIIa are not involved in the activation of the second messenger system by LDL but play a role in the proaggregant effect of LDL by providing cell-to-cell interactions.