Effects of eicosanoid and endothelial cell derived relaxing factor inhibition on fetal vascular tone and responsiveness in the human perfused placenta

Abstract

Local output of endothelial cell-derived relaxing factor (EDRF) appeared tomake a greater contribution to the low resistance of the fetal circulation of the human placenta perfused in vitro than did prostaglandins, such as prostacyclin. Whereas blockade of the effects of EDRF, using three drugs inhibiting EDRF by differing mechanisms, caused increased fetal vascular resistance, reduction of prostaglandin output using three drugs inhibiting various stages of prostaglandin biosynthesis did not. Concomitant EDRF release also appeared to be important for modulation of vasoconstrictor responses to 5-hydroxytryptamine, endothelin-1, bradykinin, and angiotensin II and was more important than prosta..