Responses of placental arteries from normotensive and preeclamptic women to endogenous vasoactive agents.
OBJECTIVE
The hypothesis that preeclampsia may be associated with an increase in the response of the placental arteries to vasoconstrictors or a decrease in their response to vasodilators was tested.


METHODS
Concentration-response curves to various agents were determined on helical strips of fetal placental arteries from normotensive (n = 33) and preeclamptic (n = 8) women to calculate the potencies and maximal effects of the agents.


RESULTS
Endothelin, prostaglandin F2 alpha, and serotonin caused concentration-dependent contractions; angiotensin II and norepinephrine produced little or no effects. The prostacyclin analog iloprost and atrial natriuretic factor, but not isoproterenol, relaxed placental arteries. Iloprost was more effective on preeclamptic than on normal arteries, but the effects of other agents on the two groups of arteries did not differ. Placental arteries exhibited spontaneous oscillations that were more marked in preeclamptic than in normal arteries and were inhibited by indomethacin.


CONCLUSIONS
Preeclampsia is not associated with an increase in the responses of fetal placental arteries to vasoconstrictors or a decrease in their response to vasodilators. However, placental arteries from preeclamptic subjects exhibit increased oscillations.
Inayatulla
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A
Department of Pharmacology and Therapeutics, McGill University, Montreal, Quebec, Canada.
Chemtob
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Nuwayhid
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Varma
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DR
D000328:Adult; D000804:Angiotensin II / Q000494:pharmacology; D001158:Arteries / Q000187:drug effects / Q000503:physiopathology*; D009320:Atrial Natriuretic Factor / Q000494:pharmacology; D015237:Dinoprost / Q000494:pharmacology; D016232:Endothelins / Q000494:pharmacology; D005260:Female; D006801:Humans; D016285:Iloprost / Q000494:pharmacology; D007545:Isoproterenol / Q000494:pharmacology; D009638:Norepinephrine / Q000494:pharmacology; D010920:Placenta / Q000098:blood supply*; D011225:Pre-Eclampsia / Q000503:physiopathology*; D011247:Pregnancy; D012701:Serotonin / Q000494:pharmacology; D014661:Vasoconstriction / Q000187:drug effects; D014662:Vasoconstrictor Agents / Q000494:pharmacology*; D014664:Vasodilation / Q000187:drug effects; D014665:Vasodilator Agents / Q000494:pharmacology*
D016232:Endothelins; D014662:Vasoconstrictor Agents; D014665:Vasodilator Agents; D000804:Angiotensin II; D012701:Serotonin; D009320:Atrial Natriuretic Factor; D015237:Dinoprost; D016285:Iloprost; D007545:Isoproterenol; D009638:Norepinephrine