Responses of placental arteries from normotensive and preeclamptic women to endogenous vasoactive agents
Article Abstract:
Preeclampsia does not appear to be associated with an increase in the placental response to vasoconstrictors or a reduction in the response to vasodilators. Preeclampsia is complication of late pregnancy characterized by high blood pressure and an increase of protein in the urine. The effects of various vasoconstrictors and vasodilators on placental arteries were measured in placentas taken from 33 healthy women and eight women with preeclampsia following delivery. Endothelin, serotonin and prostaglandin F2-alpha induced concentration-dependent contractions of the placental arteries in placentas from both groups. Angiotensin II and norepinephrine had insignificant effects on contraction. Iloprost and atrial natriuretic factor induced concentration-dependent relaxation of arteries in both groups, but iloprost had a significantly greater relaxing effect on placental arteries from preeclamptic women than those from healthy women. Spontaneous rhythmic contractions occurred more frequently in placental arteries from preeclamptic women.
Publication Name: American Journal of Obstetrics and Gynecology
Subject: Health
ISSN: 0002-9378
Year: 1993
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Absence of relaxation to lactate in human placental vessels of pregnancies with severe preeclampsia
Article Abstract:
The reduced blood flow in the placental arteries and veins seen in preeclampsia could result from a loss of response of the blood vessels to lactate. Researchers took samples of placental blood vessels following childbirth from 14 women with severe preeclampsia, 8 women who delivered prematurely and 47 women who delivered at term. The blood vessels were contracted in culture with a prostaglandin and then exposed to lactate, which normally relaxes blood vessels. The blood vessels from preeclamptic women did not respond to lactate whereas those from the other two groups did relax in response to lactate. However, blood vessels from preeclamptic women did respond to other vasodilators such as arachidonic acid, forskolin and nitroglycerin. This indicates that a specific vasodilating mechanism has been altered. Increased levels of lactate are produced when the fetus is starved of oxygen.
Publication Name: American Journal of Obstetrics and Gynecology
Subject: Health
ISSN: 0002-9378
Year: 1995
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Reactivities to serotonin and histamine in umbilical and placental vessels during the third trimester after normotensive pregnancies and pregnancies complicated by preeclampsia
Article Abstract:
The placental response to serotonin appears to change in pregnant women with preeclampsia. Preeclampsia is a complication of pregnancy. This could explain the changes in blood flow in the placenta during preeclampsia.
Publication Name: American Journal of Obstetrics and Gynecology
Subject: Health
ISSN: 0002-9378
Year: 1999
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