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# Study Explains Why Magnesium Sulfate Lowers Seizure Risk linked to Preeclampsia
- URL: https://www.foodconsumer.org/magnesium_sulfate_1120141235/
- Published: 2014-11-20T23:31:00.000Z
- Updated: 2026-09-22T16:24:53.000Z
- Description: In a rat model of severe preeclampsia, seizure threshold fell roughly 65 percent and magnesium sulfate reversed the drop. The abstract reports the rats also had greater blood-brain barrier permeability, which magnesium sulfate did not affect, plus signs of neuroinflammation.
- Author: Food Consumer
- Tags: Drug, Health News, #vivvo-import

Abstract

Eclampsia, defined as unexplained seizure in a woman with preeclampsia, is a life-threatening complication of pregnancy with unclear etiology. Magnesium sulfate (MgSO4) is the leading eclamptic seizure prophylactic, yet its mechanism of action remains unclear. Here, we hypothesized severe preeclampsia is a state of increased seizure susceptibility due to blood-brain barrier (BBB) disruption and neuroinflammation that lowers seizure threshold. Further, MgSO4 decreases seizure susceptibility by protecting the BBB and preventing neuroinflammation. To model severe preeclampsia, placental ischemia (reduced uteroplacental perfusion pressure; RUPP) was combined with a high cholesterol diet (HC) to cause maternal endothelial dysfunction. RUPP+HC rats developed symptoms associated with severe preeclampsia, including hypertension, oxidative stress, endothelial dysfunction and fetal and placental growth restriction. Seizure threshold was determined by quantifying the amount of pentylenetetrazole (PTZ; mg/kg) required to elicit seizure in RUPP+HC±MgSO4 and compared to normal pregnant controls (n?=?6/group; gestational day 20). RUPP+HC rats were more sensitive to PTZ with seizure threshold being ∼65% lower vs. control (12.4±1.7 vs. 36.7±3.9 mg/kg PTZ; p<0.05) that was reversed by MgSO4 (45.7±8.7 mg/kg PTZ; p<0.05 vs. RUPP+HC). BBB permeability to sodium fluorescein, measured in-vivo (n?=?5-7/group), was increased in RUPP+HC vs. control rats, with more tracer passing into the brain (15.9±1.0 vs. 12.2±0.3 counts/gram ×1000; p<0.05) and was unaffected by MgSO4 (15.6±1.0 counts/gram ×1000; p<0.05 vs. controls). In addition, RUPP+HC rats were in a state of neuroinflammation, indicated by 35±2% of microglia being active compared to 9±2% in normal pregnancy (p<0.01; n?=?3-8/group). MgSO4 treatment reversed neuroinflammation, reducing microglial activation to 6±2% (p<0.01 vs. RUPP+HC). Overall, RUPP+HC rats were in a state of augmented seizure susceptibility potentially due to increased BBB permeability and neuroinflammation. MgSO4 treatment reversed this, increasing seizure threshold and decreasing neuroinflammation, without affecting BBB permeability. Thus, reducing neuroinflammation may be one mechanism by which MgSO4 prevents eclampsia during severe preeclampsia.

PLoS One. 2014 Nov 19;9(11):e113670\. doi: 10.1371/journal.pone.0113670\. eCollection 2014.

Magnesium Sulfate Treatment Reverses Seizure Susceptibility and Decreases Neuroinflammation in a Rat Model of Severe Preeclampsia.

Johnson AC1, Tremble SM1, Chan SL1, Moseley J2, LaMarca B2, Nagle KJ1, Cipolla MJ3.

Author information

1Department of Neurological Sciences, University of Vermont College of Medicine, Burlington, Vermont, United States of America.

2Department of Pharmacology, University of Mississippi Medical Center, Jackson, Mississippi, United States of America.

3Department of Neurological Sciences, University of Vermont College of Medicine, Burlington, Vermont, United States of America; Department of Obstetrics, Gynecology, and Reproductive Sciences, University of Vermont College of Medicine, Burlington, Vermont, United States of America; Department of Pharmacology, University of Vermont College of Medicine, Burlington, Vermont, United States of America.

*Originally published on http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0113670*

**Copyright:* © 2014 Johnson et al. This is an open-access article distributed under the terms of the* [*Creative Commons Attribution License*](http://creativecommons.org/licenses/by/4.0/?ref=foodconsumer.org)*, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.*