Peripheral magnesium sulfate enters the brain and increases the threshold for hippocampal seizures in rats

Mordechai Hallak, Robert F. Berman, Susan M. Irtenkauf, Mark I. Evans, David B. Cotton

Research output: Contribution to journalArticlepeer-review

99 Scopus citations


OBJECTIVES: Our objectives were to determine whether magnesium sulfate crosses the blood-brain barrier and whether it has central anticonvulsant action. STUDY DESIGN: In experiment 1 34 female Long-Evans rats were divided into six groups: control (n = 7); single magnesium sulfate injection and evaluation after 20 minutes in 3 conditions: normal rats (n = 7), sham-operated animals (n = 5), and after electrical stimulation by hippocampal electrode (n = 5); single injection and evaluation after 2 hours (n = 5); and prolonged (2 hours) serum magnesium elevation (n = 5). Serum, cerebrospinal fluid, and specific brain areas were analyzed for magnesium concentrations. In experiment 2 threshold for electrical seizure was measured in eight rats before and after intraperitoneal injections of magnesium sulfate versus saline solution. RESULTS: In experiment 1 there was a significant correlation between blood and cerebrospinal fluid magnesium concentrations (r = 0.80, p < 0.0001). Magnesium concentrations were increased in the cortex and hippocampus, with the largest changes occurring after two hours of sustained serum magnesium concentrations (p < 0.01). Induction of hippocampal seizure activity resulted in further elevations in cerebrospinal fluid magnesium concentrations but did not change brain concentrations. In experiment 2 magnesium sulfate increased the electrical threshold required to induce seizures by 34% (p = 0.01). CONCLUSIONS: Magnesium sulfate enters the cerebrospinal fluid and brain and has a central anticonvulsant effect.

Original languageEnglish
Pages (from-to)1605-1610
Number of pages6
JournalAmerican Journal of Obstetrics and Gynecology
Issue number6
StatePublished - 1 Jan 1992
Externally publishedYes


  • Magnesium sulfate
  • blood-brain barrier
  • seizures

ASJC Scopus subject areas

  • Obstetrics and Gynecology


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