Effects of Sodium Chloride on Pregnant Sheep with Reduced Uteroplacental Perfusion Pressure

• Published in: Hypertension (Dallas, Tex. 1979) Tex. 1979), 1986-01, Vol.8 (1), p.62-65
• Main Authors: LEFFLER, CHARLES W, HESSLER, JACK R, GREEN, ROBERT S, FLETCHER, ANTHONY M
• Format: Article
• Language: English
• Subjects: Animals; Aorta, Abdominal - physiopathology; Applied sciences; Arterial hypertension. Arterial hypotension; Biological and medical sciences; Blood and lymphatic vessels; Blood Pressure - drug effects; Cardiology. Vascular system; Constriction; Diet; Exact sciences and technology; Experimental diseases; Female; Hypertension - physiopathology; Medical sciences; Other techniques and industries; Placenta - blood supply; Pregnancy; Pregnancy Complications, Cardiovascular - physiopathology; Sheep; Sodium Chloride - pharmacology; Uterus - blood supply
• ISSN: 0194-911X; 1524-4563
• DOI: 10.1161/01.HYP.8.1.62

This study investigated the effects of NaCl supplementation (5 mEq/kg/day) on the arterial pressure of pregnant and nonpregnant sheep with and without reduction of uteroplacental perfusion pressure. In pregnant sheep receiving NaCl supplementation during the third trimester, reduction of aortic pressure caudal to the kidneys to 65% of the upstream pressure (occlusion) caused a progressive increase in mean arterial pressure from 89 ± 3 to 110 ± 3 mm Hg over 2 weeks. Occlusion was accompanied by a decrease in urine flow. Six of seven sheep died or were killed because of severe respiratory distress. No abnormalities were detected in nonpregnant sheep or pregnant sheep receiving NaCl supplementation only. Pregnant sheep that were occluded but received no supplementary NaCl did not become hypertensive but aborted about 2 weeks after occlusion. These results indicate that reduction of uteroplacental perfusion pressure causes hypertension in NaCIsupplemented pregnant sheep but not in sheep receiving a normal, low sodium diet.