Alcohols induce rapid depletion of intracellular free Mg 2+ in cerebral vascular muscle cells: relation to chain length and partition coefficient

Abstract

Acute effects of a series of alcohols (methanol, ethanol, n-butanol) on intracellular free magnesium concentration ([Mg 2+] i in canine cerebral vascular smooth muscle cells was studied using mag-fura-2 and digital imaging microscopy. In 1.2 mM [Mg 2+] o, basal [Mg 2+] i was 500 ± 30 μM. Exposure of cells to a low concentration (25 mM) of ethanol, but not methanol, for only 30 s resulted in significant loss of [Mg2 2] i. Exposure to 100 mM methanol, ethanol, and butanol for 30 s resulted in a relative order of potency for [Mg 2+] i depletion, where butanol ⪢ ethanol > methanol. The heterogeneous and relative subcellular compartmented concentrations of [Mg 2+] i, where perinuclear > nuclear ⪢ peripheral (cytosolic) region, was not significantly altered by the alcohols. The degree of cellular depletion of [Mg 2+] i; was directly a function of each alcohol's partition coefficient and chain length. The latter is suggestive of the probability that alcohols promote intracellular depletion of Mg 2+ by partitioning in membranes and disordering lipid bilayers.