title: Circulatory effects of magnesium sulfate in normotensive and renal hypertensive pregnant sheep.
abstract: We have studied the effects of magnesium sulfate (MgSO4) administration in chronically instrumented normotensive and hypertensive pregnant sheep. Animals of 90 to 144 days' gestation were divided in two groups; those with normotensive arterial pressure and those in which renovascular hypertension had been produced. Our results show that bolus injection of 2 or 4 Gm. of MgSO4 caused a transient decrease in systolic and diastolic pressure which returned to control values within 5 to 10 minutes. The continuous infusion of MgSO4 in doses of 2 or 4 Gm. per hour produced a slight increase in uteroplacental blood flow but did not alter the blood pressure. Heart rate showed a slight increase. Because MgSO4 produced no significant hemodynamic changes, we feel that: (1) its use in obstetrics must be based on its anticonvulsant action and (2) MgSO4 in either normotensive or hypertensive patients is not associated with impairment of uteroplacental blood flow.
mesh_terms: D000818:Animals; D001794:Blood Pressure / Q000187:drug effects*; D001806:Blood Urea Nitrogen; D003404:Creatinine / Q000097:blood; D004573:Electrolytes / Q000097:blood; D005260:Female; D006339:Heart Rate / Q000187:drug effects*; D006977:Hypertension, Renal / Q000188:drug therapy; D008274:Magnesium / Q000097:blood; D008278:Magnesium Sulfate / Q000494:pharmacology* / Q000627:therapeutic use; D010920:Placenta / Q000098:blood supply*; D011247:Pregnancy; D012039:Regional Blood Flow / Q000187:drug effects; D012756:Sheep; D014599:Uterus / Q000098:blood supply*
chemical_list: D004573:Electrolytes; D008278:Magnesium Sulfate; D003404:Creatinine; D008274:Magnesium