In vitro effect of bioactive natriuretic peptides on perfusion pressure inplacentas from normal and pre-eclamptic pregnancies

The number of placental vascular guanylate-coupled receptors, corresponding to bioactive natriuretic peptide receptors is greater in preeclampsia, but there are no clear data about atrial natriuretic peptide (ANP) concentrati on in preeclampsia. The influence of various doses of ANP and urodilatin (U RO) on placental perfusion pressure in preeclampsia was investigated by per fusing 16 human placentas in vitro. The placental vessels were submaximally preconstricted by continuous infusion of N-omega-nitro-L-arginine (NOLA). Perfusion pressure was measured continuously. Over 180 min various doses of alpha ANP or URO were administrated (25, 50, 100, 200 nmol/l, 2 min increm ents). The effects of pretreatment with the guanylate cyclase inhibitor, LY 83583 was also examined. We found that ANP and URO attenuated NOLA-induced vasoconstriction, that URO given in higher doses produced stronger vasocil ation than ANP, and that the mean decrease of perfusion pressure was higher in preeclampsia. The possibility of a non cGMP-mediated pathway of ANP and URO action should be considered.