Magnesium deficiency exacerbates brain injury and stroke mortality induced by alcohol: a 31P-NMR in vivo study.

Mimicking in rats the reduced level of dietary magnesium (Mg) intake, seen in present-day Western World populations, short-term (4 weeks) restriction of Mg intake (30-35% normal) resulted in a 40% loss in brain intracellular free Mg2+ ions ([Mg2+]i) and significant rises in brain intracellular pH (pHi) and phosphocreatine ([PCr]) but no change in [ATP] or [Pi] as measured by 31P-NMR spectroscopy. Such Mg-deficient animals (serum Mg fell 65%), when given ED40 stroke doses of ethanol, demonstrated a 100% stroke mortality. These findings indicate that: 1) moderate, short-term Mg deficiency makes the brain vulnerable to hypoxic-lethal stroke insults induced by alcohol administration, and 2) brain [Mg2+]i appears to play an important role in finely regulating brain pHi and [PCr].