Prostacyclin contributes to nitroglycerin-mediated relaxation of human umbilical arteries

This study compared the action of nitroglycerin (GTN) and linsidomine (SIN-1) on vessel tone and prostacyclin (PGI2) production of human umbilical arteries in vitro. GTN-induced vessel relaxation was significantly attenuated by indomethacin pretreatment. This was associated with a significant inhibition of the fourfold stimulation of PGI2 release by GTN. No such effects were seen with SIN-1. We concluded that GTN-induced PGI2 release contributed to the vasodilatory action of organic nitrates in the fetoplacental circulation.