TY - JOUR

T1 - Association of ethanol with lipid membranes containing cholesterol, sphingomyelin and ganglioside

T2 - A titration calorimetry study

AU - Trandum, Christa

AU - Westh, Peter

AU - Jørgensen, Kent

AU - Mouritsen, Ole G.

PY - 1999/8/20

Y1 - 1999/8/20

N2 - 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.

AB - 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.

KW - Alcohol-membrane interaction

KW - Calorimetry

KW - Lipid bilayer

KW - Lipid composition

KW - Partitioning coefficient

UR - http://www.scopus.com/inward/record.url?scp=0032808920&partnerID=8YFLogxK

U2 - 10.1016/S0005-2736(99)00092-9

DO - 10.1016/S0005-2736(99)00092-9

M3 - Journal article

C2 - 10446301

AN - SCOPUS:0032808920

VL - 1420

SP - 179

EP - 188

JO - B B A - Biomembranes

JF - B B A - Biomembranes

SN - 0005-2736

IS - 1-2

ER -