Association of ethanol with lipid membranes containing cholesterol, sphingomyelin and ganglioside: A titration calorimetry study

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The association of ethanol at physiologically relevant concentrations with lipid bilayers of different lipid composition has been investigated by use of isothermal titration calorimetry (ITC). The liposomes examined were composed of combinations of lipids commonly found in neural cell membranes: dimyristoyl phosphatidylcholine (DMPC), ganglioside (GM1), sphingomyelin and cholesterol. The calorimetric results show that the interaction of ethanol with fluid lipid bilayers is endothermic and strongly dependent on the lipid composition of the liposomes. The data have been used to estimate partitioning coefficients for ethanol into the fluid lipid bilayer phase and the results are discussed in terms of the thermodynamics of partitioning. The presence of 10 mol% sphingomyelin or ganglioside in DMPC liposomes enhances the partitioning coefficient by a factor of 3. Correspondingly, cholesterol (30 mol%) reduces the partitioning coefficient by a factor of 3. This connection between lipid composition and partitioning coefficient correlates with in vivo observations. Comparison of the data with the molecular structure of the lipid molecules suggests that ethanol partitioning is highly sensitive to changes in the lipid backbone (glycerol or ceramide) while it appears much less sensitive to the nature of the head group. Copyright (C) 1999 Elsevier Science B.V.

Original languageEnglish
JournalBiochimica et Biophysica Acta - Biomembranes
Issue number1-2
Pages (from-to)179-188
Number of pages10
Publication statusPublished - 20 Aug 1999

    Research areas

  • Alcohol-membrane interaction, Calorimetry, Lipid bilayer, Lipid composition, Partitioning coefficient

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