title: Demonstration of high-affinity binding sites for C3a anaphylatoxin on guinea-pig platelets.
abstract: 3H-serotonin release from guinea-pig platelets was demonstrated to be the consequence of C3a binding to these cells. A Scatchard analysis of dose-response data of the 125I-C3a binding pattern to guinea-pig platelets pointed to the existence of binding sites with high and low affinity for the C3a molecule (HA and LA receptors). HA receptors are specific for C3a with intact C-terminal arginine. whereas C3adesarg only interacts with LA receptors. The release of serotonin may be induced by a combined reaction of C3a with HA receptors and LA receptors on the platelet membrane.
mesh_terms: D000706:Anaphylatoxins; D000818:Animals; D001665:Binding Sites; D001792:Blood Platelets / Q000276:immunology*; D002268:Carboxypeptidases / Q000494:pharmacology; D003176:Complement C3; D006168:Guinea Pigs; D010455:Peptides; D012701:Serotonin / Q000378:metabolism; D013696:Temperature
chemical_list: D000706:Anaphylatoxins; D003176:Complement C3; D010455:Peptides; D012701:Serotonin; D002268:Carboxypeptidases