Effect of prostacyclin on the perfusion pressure and on the vasoconstrictor response of angiotensin II in the human isolated foetal placental circulation.

The effect of prostacyclin infusion on the perfusion pressure and on the vasoconstrictor response to three doses of angiotensin II was investigated in six full-term human placentas. The placentas were perfused with a modified Krebs-Henseleit solution and placenta perfusion pressure was recorded. Prostacyclin 5 X 10(-8) M, infused through the foetal placental circulation, produced a significant decrease in placental vascular resistance. The vasodepressor effect of prostacyclin persisted throughout the perfusion period and promptly disappeared when the infusion was stopped. The pressor response of angiotensin II was significantly reduced by prostacyclin infusion. These data suggest an interaction between the vascular effects of prostacyclin and angiotensin II on the placental circulation that might be important in the control of foetal placental blood flow.