Platelet adhesion to native collagens involves proteoglycans and may be a two-step process.
Adhesion of rat blood platelets to native rat tail collagen fibrils was studied in the electron microscope under conditions that preserved collagen-associated proteoglycans (CAPG). The CAPG molecules were aligned in chain-like configurations that encircled the fibrils with a 65 nm period; they appeared to coat the fibrils completely and extended 60-100 nm away from the fibril. The initial platelet-fibril contact occurred between the platelet glycocalyx and the CAPG of the fibrils i.e. between two surfaces with net-negative charges. When close contact was established between the fibril surface proper and the platelet membrane, CAPG were not identified in the area of contact, and the collagen-platelet distance was reduced to a approximately 10-12 nm wide gap traversed by delicate links in register with fibril periodicities.
Behnke
O
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Institute of Anatomy, Panum Institute, Copenhagen, Denmark.
D000818:Animals; D001665:Binding Sites; D001792:Blood Platelets / Q000378:metabolism / Q000648:ultrastructure; D003094:Collagen / Q000378:metabolism*; D066298:In Vitro Techniques; D008854:Microscopy, Electron; D010973:Platelet Adhesiveness; D011509:Proteoglycans / Q000378:metabolism*; D051381:Rats
D011509:Proteoglycans; D003094:Collagen