Trombocytenreceptoren: huidige inzichten en behandelingsmogelijkheden

In the action of thrombocytes during stemming of a bleeding after damage to a blood vessel, receptors on the thrombocyte membrane play an important part. Adhesion of platelets takes place via specific binding of receptors; the main binding is that of glycoprotein (Gp) Ib to Von Willebrand factor which is synthetized by endothelial cells. Activation of thrombocytes is stimulated by adhesion and by agonists. Weak agonists, through production of thromboxane A2 and release of agonists from granules cause a self-fortifying process of thrombocyte stimulation; strong agonists (like thrombin) lead also to activation of Gp IIb/IIIa receptors. Aggregation of thrombocytes occurs after activation of Gp IIb/IIIa receptors. During stimulation, a change of shape occurs which enables binding to suitable plasma proteins of which the main one is fibrinogen. Knowledge of thrombocyte receptors enhances the insight into the prognosis and efficacy of certain treatments in diseases in which platelet aggregation is pivotal. Of the six categories of antiplatelet drugs, antagonists of Gp IIb/IIIa receptors are the most potent. In clinical trials good results have been obtained in patients with coronary disease of the intravenously administered form added to acetylsalicylic acid