Low concentrations of ethanol deplete type-2 astrocytes of intracellular free magnesium

The acute effects of low concentrations of ethanol on intracellular free ma gnesium ions ([Mg2+](i)) in cultured type-2 astrocytes were studied by digi tal imaging microscopy using the Mg2+ fluorescent probe, mag-fura-2. In 0-m M ethanol, the basal level of [Mg+](i) was 124.7 +/- 2.56 mu M with a heter ogeneous distribution within the cells. Treatment of the cells with 10 and 25 mM ethanol (10 min) resulted in rapid concentration-dependent reduction in [Mg2+](i); the greater the concentration of alcohol, the greater the dep letion of [Mg2+](i) Exposure of cells to 10 and 25 mM resulted in approxima tely 27 and 50% reductions in [Mg2+](i) respectively. Reincubation in norma l Mg2+-physiological buffer solution restored [Mg2+](i) levels. These obser vations may suggest that acute "binge drinking" of ethanol, which often res ults in cerebral ischemia and stroke, may do so as a result of depletion of astrocytic [Mg2+](i) possibly producing disruption of the blood-brain barr ier. All rights reserved (C) 1999 Elsevier Science Inc.