Magnesium sulfate effectively reduces blood pressure in an animal model of preeclampsia.
OBJECTIVE
We tested the ability of magnesium sulfate to reduce hypertension and neonatal growth retardation in an animal model of preeclampsia.


METHODS
On day 17 of pregnancy, osmotic minipumps were inserted subcutaneously to continuously deliver either vehicle (saline control group), or N-nitro-L-arginine methyl ester (L-NAME) (50 mg/kg/day), or L-NAME (50 mg/kg/day) in combination with magnesium sulfate (60 mg/kg/day). Prior to insertion, blood pressure and heart rate were monitored with a pneumatic tail cuff device. Blood pressure measurements were repeated on days 18, 20, and 21 of pregnancy. Blood was obtained on days 17 and 21, along with urine, to assess magnesium levels and degree of proteinuria. Pups were weighed and measured at 48 hours postpartum.


RESULTS
Rats receiving L-NAME developed hypertension within 24 hours of implantation (108 +/- 3.9 vs. 123 +/- 3.4 mmHg, p < 0.05). Magnesium sulfate, given along with L-NAME did not prevent mean blood pressure from increasing, but reduced it by day 21 compared to L-NAME given alone (107 +/- 3.4 vs. 122 +/- 8.7 mmHg, respectively, p < 0.05). Magnesium sulfate reduced neonatal growth retardation by improving the weight of the pups compared to pups from maternal rats given L-NAME alone (6.1 +/- 0.1 vs. 5.2 +/- 0.3 grams, respectively, p < 0.05).


CONCLUSIONS
Maternal magnesium sulfate reduces blood pressure and increases neonatal size compared to L-NAME without magnesium. These findings support a beneficial effect of magnesium in preeclampsia.
Standley
Cynthia A
CA
Division of Physiology, Midwestern University, Arizona College of Osteopathic Medicine, Glendale, 85308, USA. cstand@midwestern.edu
Batia
Lyn
L
Yueh
Gloria
G
D000818:Animals; D000831:Animals, Newborn; D000927:Anticonvulsants / Q000494:pharmacology; D001794:Blood Pressure / Q000187:drug effects*; D004195:Disease Models, Animal; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005260:Female; D005317:Fetal Growth Retardation / Q000188:drug therapy / Q000503:physiopathology; D005552:Forelimb / Q000002:abnormalities / Q000187:drug effects; D006339:Heart Rate / Q000187:drug effects; D008278:Magnesium Sulfate / Q000494:pharmacology*; D019331:NG-Nitroarginine Methyl Ester / Q000494:pharmacology; D019001:Nitric Oxide Synthase / Q000037:antagonists & inhibitors; D011225:Pre-Eclampsia / Q000188:drug therapy* / Q000503:physiopathology; D011247:Pregnancy; D051381:Rats; D017207:Rats, Sprague-Dawley; D016896:Treatment Outcome
D000927:Anticonvulsants; D004791:Enzyme Inhibitors; D008278:Magnesium Sulfate; D019001:Nitric Oxide Synthase; D019331:NG-Nitroarginine Methyl Ester