Exchange of cyclooxygenase dependent metabolites between vessel wall and platelets in arterial thrombosis

In this investigation, transport of endoperoxides from the vessel wall to the platelets in an in vivo model for the induction and quantification of platelet thrombosis is described. Thrombi are induced in a branch of the mesenteric artery of the male white Wistar rat through topical superfusion of adenosine diphosphate solutions following focal de-endothelialization by means of a small electrical current in two groups, comparing untreated rats to acetylsalicylic acid (ASA) treated ones. In the latter group the cyclooxygenase activity of the platelets is completely inhibited but not so that of the endothelial cells. In both groups arachidonic acid enhances adenosine diphosphate induced arterial platelet thrombosis most likely through the conveyance of endoperoxides generated in the vessel wall to the platelets as thromboxane synthetase antagonists as well as thromboxane receptor blocking agents completely inhibit this enhancement in both groups. Furthermore it is demonstrated that ASA treated animals show an increased propensity to thrombosis induced by adenosine diphosphate.