Sipes S L, Chestnut D H, Vincent R D, Weiner C P, Thompson C S, Chatterjee P
Department of Obstetrics and Gynecology, University of Iowa Hospitals and Clinics 52242.
Anesthesiology. 1991 Dec;75(6):1010-8. doi: 10.1097/00000542-199112000-00013.
Magnesium sulfate (MgSO4) attenuates the maternal compensatory response to hemorrhage in gravid ewes, perhaps by decreasing the response to endogenous vasopressors. The purpose of this study was to determine whether MgSO4 alters the cardiovascular response of gravid ewes to vasopressor agents. Sixteen gravid ewes underwent a series of experiments consisting of administration of two exogenous and two endogenous vasopressors, each with and without a concurrent MgSO4 infusion. Dose-response curves were constructed for phenylephrine (an alpha 1-adrenergic agonist), ST-91 (an alpha 2-adrenergic agonist), angiotensin II, and arginine vasopressin (AVP). MgSO4 significantly attenuated the increase in maternal mean arterial pressure and systemic vascular resistance and the decrease in cardiac output during ST-91 infusion but not during phenylephrine, angiotensin II, or AVP infusions. MgSO4 significantly attenuated the increase in uterine vascular resistance during phenylephrine, ST-91, and angiotensin II infusions and the decrease in uterine blood flow during phenylephrine and angiotensin II infusions. MgSO4 also appeared to attenuate the decrease in uterine blood flow during ST-91 infusion (P = 0.067). The present study suggests that MgSO4 antagonizes the effects of alpha 1-adrenergic agonists, alpha 2-adrenergic agonists, and angiotensin II on the uterine vasculature, thus providing a level of protection for the fetus in situations of maternal stress.
硫酸镁（MgSO₄）可能通过降低对内源性血管加压素的反应，减弱妊娠母羊对出血的母体代偿反应。本研究的目的是确定MgSO₄是否会改变妊娠母羊对血管加压药的心血管反应。16只妊娠母羊接受了一系列实验，包括给予两种外源性和两种内源性血管加压素，每种药物在同时输注和不输注MgSO₄的情况下进行。构建了去氧肾上腺素（一种α₁肾上腺素能激动剂）、ST - 91（一种α₂肾上腺素能激动剂）、血管紧张素II和精氨酸加压素（AVP）的剂量 - 反应曲线。MgSO₄显著减弱了在输注ST - 91期间母体平均动脉压和全身血管阻力的增加以及心输出量的减少，但在输注去氧肾上腺素、血管紧张素II或AVP期间没有这种作用。MgSO₄显著减弱了在输注去氧肾上腺素、ST - 91和血管紧张素II期间子宫血管阻力的增加，以及在输注去氧肾上腺素和血管紧张素II期间子宫血流量的减少。MgSO₄似乎也减弱了在输注ST - 91期间子宫血流量的减少（P = 0.067）。本研究表明，MgSO₄拮抗α₁肾上腺素能激动剂、α₂肾上腺素能激动剂和血管紧张素II对子宫血管系统的作用，从而在母体应激情况下为胎儿提供一定程度的保护。
