Membranes and the Genetics of Ethanol Response

A combination of fluorescence polarization (FPZ) and nuclear magnetic resonance (NMR) techniques have revealed that ethanol has diverse and domain dependent effects on membrane order. Under some conditions, in the more superficial membrane domains, ethanol actually orders rather disorders membrane structure. Using 1H-NMR we have examined in synaptic membranes from LS and SS mice the effects of ethanol-d6 on membrane order. The lines differ most significantly in terms of the ethanol effects on the choline methyl resonances. Ethanol was significantly more potent in increasing choline methyl resonance intensity in LS synaptic membranes than in SS synaptic membranes; these data are interpreted to show a significantly greater disordering of the superficial domains in the LS membranes. The maximum ethanol effect was observed between 0.3% and 0.5% for the concentration range studied (0.1 to 1.0%). The methylene resonance data in general paralleled the choline methyl resonance data but with a somewhat attenuated response. Ethanol had only small effects on the terminal methyl resonance in both lines. Overall, we conclude that the LS and SS mice differ in the ethanol-induced perturbation of membrane structure, primarily at more superficial membrane domains.