Magnesium sulfate reduces seizures induced by central administration of the excitatory amino acid n-methyl-d-aspartate in rats

Cynthia A. Standley, Susan M. Irtenkauf, Brian A. Mason, William J. Kupsky, David B. Cotton

Research output: Contribution to journalArticle

4 Scopus citations

Abstract

A'-Methyl-D-aspartate (NMDA) has been implicated in a number of pathophysiologic conditions, including seizures. Magnesium is a physiologic blocker of the NMDA receptor. As magnesium sulfate (MgSO4) is currently used as a treatment for eclamptic seizures in North America, we examined the anticonvulsant effects of MgSO4 on central NMDA-induced seizures. Forty-one female rats were surgically anesthetized and a bipolar recording electrode was stereotaxically implanted into the dorsal hippocampus, while a cannula was implanted into the lateral cerebral ventricle for drug injection. Following 1-week recovery, baseline behavior and electrical activity were recorded. Two treatment protocols were examined: (a) chronic-intraperitoneal injection of 270 mg/kg MgSO4, followed every 20 min with 27 mg/kg MgSO4 for a total of 2 h; and (b) acute-intravenous injection of MgSO4 (30, 60, or 90 mg/kg) in a volume of 1.5 mL/kg via the tail vein. Following either treatment protocol, rats received 1 μ;L of 20 mg/mL NMDA via the cannula, and seizure activity was assessed. Onset to the first seizure was significantly lengthened in rats receiving both chronic (P < 0.01) and acute (P < 0.01) MgS04. Total seizure number was significantly reduced in the chronic MgSO4 group (P < 0.05). Total seizure duration was significantly reduced in both the chronic (P < 0.05) and acute (P < 0.05) MgSO4 groups. Mortality was 30% in the chronic control group, whereas none of the rats that received chronic MgSO4 died. We conclude that magnesium sulfate reduces seizure activity induced by centrally administered NMDA. These results support our previous observations that magnesium does have central anticonvulsant effects.

Original languageEnglish (US)
Pages (from-to)235-244
Number of pages10
JournalHypertension in Pregnancy
Volume14
Issue number2
DOIs
StatePublished - Jan 1 1995

Keywords

  • Eclampsia
  • Excitatory amino acids
  • Magnesium
  • Seizures

ASJC Scopus subject areas

  • Internal Medicine
  • Obstetrics and Gynecology

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