Subcutaneously applied magnesium protects reliably against quinolinate-induced N-methyl-D-aspartate (NMDA)-mediated neurodegeneration and convulsions in rats: are there therapeutical implications.

Quinolinate (QUIN), an agonist of the N-methyl-D-aspartate (NMDA) subtype of the glutamate receptor, was used to model glutamate-induced primary or secondary brain damage. Rats intracerebroventricularly injected with QUIN (1 mumol in 2 microliters) showed convulsive reactions and heavy neurodegeneration in the hippocampal formation. MgSO4 (1 M solution injected subcutaneously; 0.6 or 0.3 g/kg) was found to protect completely against QUIN neurotoxicity if administered simultaneously or 1 h after exposure to QUIN. Preliminarily, LD50 for MgSO4 was estimated approximately at 1.2 g/kg. The application of magnesium is discussed to be a potentially powerful therapeutic principle in case of brain injury and convulsive disorders.