Nitric oxide production by human umbilical vessels in severe pre-eclampsia.
OBJECTIVE
Pre-eclampsia is characterized by an increased vascular tone which might be related to an abnormal endothelial cell function. As representatives of the fetal circulation, we compared the nitric oxide (NO)-releasing capacity of human umbilical vessels from normal and pre-eclamptic pregnancies.


METHODS
Normal and pre-eclamptic umbilical vessels were mounted in parallel in an organ chamber with three perfusion lines superfusing the same detector tissue (rubbed rat aortic ring). In this cascade system the capacity of the umbilical vessels to release NO was measured under basal conditions and after stimulation with histamine, bradykinin or calcium ionophore A23187.


RESULTS
Relaxations dependent on basal NO release were found to be significantly higher in pre-eclamptic vessels (especially in veins) than in normal vessels. Conversely, stimulated NO release in response to histamine or bradykinin was significantly decreased in pre-eclamptic umbilical arteries, but not in veins, compared with normal vessels. However, there was no significant difference in the release of NO in response to A23187 between normal and pre-eclamptic vessels.


CONCLUSIONS
The NO-releasing and NO-producing capacity in the vessels from fetal circulation is not diminished in pre-eclampsia. However, in pre-eclamptic umbilical arteries the NO release in response to certain stimuli (histamine or bradykinin) is diminished, probably as a result of alterations in the receptor function.
Akar
F
F
Department of Pharmacology, Faculty of Pharmacy, Gazi University, Ankara, Turkey.
Ark
M
M
Uydeş
B S
BS
Soysal
M E
ME
Saraçoğlu
F
F
Abacioğlu
N
N
Van de Voorde
J
J
Kanzik
I
I
D000328:Adult; D000818:Animals; D001011:Aorta / Q000187:drug effects / Q000378:metabolism* / Q000503:physiopathology; D001681:Biological Assay; D000001:Calcimycin / Q000494:pharmacology; D005260:Female; D006632:Histamine / Q000494:pharmacology; D006801:Humans; D066298:In Vitro Techniques; D009569:Nitric Oxide / Q000096:biosynthesis*; D009638:Norepinephrine / Q000494:pharmacology; D011225:Pre-Eclampsia / Q000378:metabolism* / Q000503:physiopathology; D011247:Pregnancy; D051381:Rats; D014469:Umbilical Arteries / Q000187:drug effects / Q000378:metabolism* / Q000503:physiopathology; D014471:Umbilical Veins / Q000187:drug effects / Q000378:metabolism* / Q000503:physiopathology; D014661:Vasoconstriction / Q000187:drug effects; D014664:Vasodilation / Q000187:drug effects
D009569:Nitric Oxide; D000001:Calcimycin; D006632:Histamine; D009638:Norepinephrine