Abstract
Human endothelial cells were cultured from umbilical cord veins using Gimbrone's method. The cultured cells were identified as endothelial cells by morphology, growth pattern and the presence of Weibel-Palade bodies. After 5 minutes incubation of platelet rich plasma with endothelial cells, ADP-induced platelet aggregation (10μM) was completely inhibited. 2×105 cultured endothelial cells indicated the same inhibitory effect on platelet aggregation as the effect of authentic prostacyclin, 10ng/ml. This inhibitory effect was completely blocked after the addition of aspirin (5μM) on the cell culture medium.