Alterations of wheat-germ agglutinin binding pattern on cell surface of blood platelets after thrombin stimulation

• Published in: Histochemistry 1989-01, Vol.91 (6), p.461-467
• Main Authors: DAIMON, T, SANO-MARTINS, I. S
• Format: Article
• Language: English
• Subjects: Binding Sites; Biological and medical sciences; Blood coagulation. Blood cells; Blood Platelets - drug effects; Blood Platelets - metabolism; Blood Platelets - ultrastructure; Calcium - pharmacology; Cell Membrane - metabolism; Cell Membrane - ultrastructure; Fundamental and applied biological sciences. Psychology; Gold Colloid; Humans; Membrane Glycoproteins - metabolism; Microscopy, Electron; Molecular and cellular biology; Platelet; Platelet Aggregation - drug effects; Staining and Labeling; Thrombin - pharmacology; Wheat Germ Agglutinins - metabolism
• ISSN: 0301-5564; 1432-119X
• DOI: 10.1007/BF00492516

An attempt was made to demonstrate wheat-germ agglutinin (WGA) binding sites on platelet surfaces after thrombin stimulation, by means of a post-embedding cytochemical technique using colloidal gold as marker at an ultrastructural level. In unstimulated platelets washed with EDTA, an intense uniform labeling of WGA-gold complexes was found on the surface membrane. When washed platelets were stimulated by thrombin in the absence of Ca2+, only a release reaction was induced. WGA labeling on the surface membranes of these platelets decreased dramatically. However, the labeling intensity of WGA-gold complexes on the surface membrane of aggregated platelets induced by thrombin in the presence of Ca2+ increased significantly compared to that of thrombin-stimulated platelets in the absence of Ca2+. In contrast to the uniform labeling on the surface membranes of unstimulated platelets, clusters of gold label were often found on the surface membrane of the aggregated platelets, although there was no significant quantitative difference in the labeling intensity between these two groups. Thus, we present direct morphological evidence demonstrating qualitative and quantitative alterations of WGA labeling on the surface membrane of platelets after thrombin stimulation. The possibility is considered that WGA-binding glycoproteins in the surface membrane are involved in the aggregation response after thrombin stimulation.