Effects of ouabain on the isolated human uteroplacental vasculature

• Published in: American journal of obstetrics and gynecology 1998-05, Vol.178 (5), p.892-898
• Main Authors: Glavind-Kristensen, Marianne, Petersen, Olav B., Forman, Axel
• Format: Article
• Language: English
• Subjects: 15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5,13-dienoic Acid - pharmacology; Arteries - physiology; Biological and medical sciences; Blood Flow Velocity - drug effects; Drug toxicity and drugs side effects treatment; Endothelium, Vascular - physiology; Female; human intramyometrial arteries; human stem villous vessels; Humans; Medical sciences; Muscle Contraction - drug effects; Muscle Relaxation - drug effects; Muscle, Smooth, Vascular - drug effects; Muscle, Smooth, Vascular - physiology; nitric oxide; Nitric Oxide - pharmacology; Ouabain; Ouabain - pharmacology; perfused placental cotyledon; Pharmacology. Drug treatments; Placenta - blood supply; Potassium - pharmacology; Pregnancy; Toxicity: urogenital system; Uterus - blood supply
• ISSN: 0002-9378; 1097-6868
• DOI: 10.1016/S0002-9378(98)70520-4

OBJECTIVE: We sought to describe the effects of ouabain on the human uteroplacental vasculature. STUDY DESIGN: Stem villous vessels and intramyometrial arteries isolated from placental and myometrial biopsy specimens at term were mounted in organ baths. Moreover, isolated human placental cotyledons were perfused. RESULTS: Contractions induced by the thromboxane A 2 analog U46619 were unaffected by pretreatment with ouabain 10 –10 to 10 –6 mol/L. In fetal vessels nitric oxide (10 –8 to 3 × 10 –5 mol/L) induced relaxation of vascular tonus induced by U46619 and potassium. This relaxation was inhibited by pretreatment with ouabain 10 –7 to 10 –6 mol/L. These associations were unaffected by removal of the endothelium. In maternal arteries ouabain (10 –6 mol/L) failed to significantly affect nitric oxide–induced relaxation. Ouabain (10 –9 mol/L) significantly affected pressure-flow relationships in perfused cotyledons. CONCLUSIONS: Ouabain impairs nitric oxide–induced relaxation of human stem villous arteries and veins, which may explain the changes induced by therapeutically relevant concentrations of the drug on pressure-flow relationships in the perfused cotyledon. Thus treatment with cardiac glycosides in pregnancy may impair uteroplacental blood flow. (Am J Obstet Gynecol 1998;178:892-8.)