Perfusion pressure changes after ANP administration in preeclampsia: in vitrostudy

Introduction

Regulation of the blood flow in human placental tissue by changes of the vascular resistance is very particular, because of lack of sympathetic innervation in placental vessels [1]. The number of guanylate-coupled receptors in placental (issues, corresponding to ANP-receptors, has been found to be greater in preeclampsia, than in normal pregnancy [2]. The aim of the study was to investigate the influence of various doses of atrial natriuretic peptide (ANP) on perfusion pressure in preeclampsia.

Methods

Heparinized placentas (n = 14) obtained after preeclamp tic (n = 7; 1st group) and normal (n = 7; 2nd group, control) pregnancies delivered at term by cesarean sections were perfused in vitro using modified Cedard manner. Perfusion pressure, measured continuously, was the main parameter of the vascular status changes. The placental vessels were submaximally preconstricted by continuous infusion of the nitric-oxide synthase inhibitor N-?)-nitro-L-arginine (NOLA; 100 µmol/l, 10 min). Over 120 min depending on the period of experiment (30, 45, 60, 75 min) human synthetic aANP were administered (25, 50, 100, 200 nmol/l, 2 min increments).

Results

Mean value of perfusion pressure increase after NOLA infusion was 5.63 kPa (± SD 0,36), the differences between groups I and II did not reach statistical significance.

Conclusion

The responsiveness of the fetoplacental vasculature to the ANP given in higher doses (100, 200 nmol/l, 2 min increments) is increased in preeclampsia (P < 0.05).

Table Perfusion pressure decrease (kPa) after a ANP administration (mean values ± SD)