AN ANTITHROMBOTIC ACTION OF HIGH-DOSE DOPAMINE IN THE RAT

The weight of thrombus formed in one hour on intravascular platinum wi res, 2 cm long and 0.5 mm in diameter, varies between individuals. Adr enaline is known to accelerate blood clotting. We tested the thromboti c effects of high-dose dopamine, precursor of adrenaline. Thrombus wei ght, venous and arterial, was measured in 98 test rats, male and femal e, treated with an infusion of dopamine for one hour. Three different doses 10, 44 and 166 mu g kg(-1) min(-1) were used. The lowest dose ha d no effect, while the medium and highest doses reduced venous thrombu s weight significantly as compared to 96 controls. Arterial thrombus w as reduced significantly in the case of female rats given medium-dose and male rats given high-dose dopamine. Tests performed after one hour on high-dose dopamine-treated rats showed increased levels of antithr ombin III, euglobulin lysis, and prolongation of the thromboplastin-he parin time.