Role of the recombinant protein of the platelet receptor for type I collagen in the release of nitric oxide during platelet aggregation

Nitric oxide plays an important role in platelet function and platelets pos sess the endothelial isoform of nitric oxide synthase. Several reports have indicated that nitric oxide is released upon exposure of platelets to coll agen. We have reported that a non-integrin platelet protein of 65 kDa is a receptor for type I collagen. By direct measurement of NO release from wash ed human platelets suspended in Tyrode buffer with a ISO-NO Mark TI, World Precision Instruments, Sarasota, FL, USA, p30 sensor, type I collagen, but not ADP and epinephrine, induces the release of NO in a time-dependent mann er. The production of NO is inhibited either by preincubation of type I col lagen with the platelet type I collagen receptor recombinant protein or by preincubation of platelets with the antibody to the receptor protein, the a nti-65 antibody. However, preincubation of platelets with anti-P-selectin a nd anti-glycoprotein IIb/IIIa did not affect the release of NO by platelets . These results suggest that the 65 kDa platelet receptor for type I collag en is specifically linked to the generation of NO, and that the 65 kDa plat elet receptor for type I collagen plays an important new role in platelet f unction. (C) 2000 Elsevier Science Ltd. All rights reserved.