Anesthetics may restructure the hydrogen belts of membranes

Brockerhoff, H.

doi:10.1007/bf02534599

Cited by 27 publications

(5 citation statements)

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“…In the case of ethanol binding, it is reasonable to regard the lipid-water interface as a model for a general hydrophilic hydrophobic interface, such that ethanol binding can be expected to occur with proteins as well as lipids (including glycoproteins and glycolipids). As suggested earlier by Brockerhoff (1982) and Klemm (1990), such interactions in the interfacial region of membrane lipids and/or proteins may influence neuronal membrane function, leading to some of the physiological effects of ethanol.…”

mentioning

confidence: 73%

Effects of Ethanol on Lipid Bilayers Containing Cholesterol, Gangliosides, and Sphingomyelin

Barry¹,

Gawrisch²

1995

Biochemistry

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The influence of lipid composition on the response of bilayers to ethanol binding was investigated with 2H NMR spectroscopy. The bilayers were composed of various combinations of the lipids most often found in neural cell membranes: phosphatidylcholines (PCs), gangliosides, sphingomyelin, and cholesterol. The PCs, 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC) and 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC), were chain-perdeuterated to allow the response of bilayer order to ethanol to be monitored at all positions through the depth of the bilayer interior. All bilayers were investigated in the lamellar liquid-crystalline (L alpha) phase. The results from the de-Paked NMR spectra demonstrate that ethanol binding in the lipid-water interface [Barry, J. A., & Gawrisch, K. (1994) Biochemistry 33, 8082-8088] alters order parameter profiles in the bilayer interior differently for the various lipid mixtures. The presence of 10 mol % brain gangliosides enhanced the disordering effect of ethanol and altered the response of the order profile along the PC chains. This effect was apparently caused by sugar-ethanol interactions in the oligosaccharide head group. The impact of the ceramide moiety of brain sphingomyelin (50 mol % in DMPC) was negligible. In bilayers containing cholesterol, the binding of ethanol and its effects on the hydrocarbon interior were found to reflect the phase transition to the liquid-ordered phase at about 25 mol % cholesterol [Thewalt, J. L., & Bloom, M. (1992) Biophys. J. 63, 1176-1181]. Results from the quadrupolar splittings for deuterated ethanol (CH3CD2OH) bound to cholesterol-containing bilayers showed that ethanol binding decreased with increasing amounts of cholesterol.(ABSTRACT TRUNCATED AT 250 WORDS)

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confidence: 73%

Effects of Ethanol on Lipid Bilayers Containing Cholesterol, Gangliosides, and Sphingomyelin

Barry¹,

Gawrisch²

1995

Biochemistry

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“…25 Therefore, bilayer dehydration produces a less-structured, or more-fluid, membrane. Brockerhoff 67 indirectly referred to this as a restructuring of the "hydrogen belt," where the presence of an anesthetic redirects the hydrogen-bonding network in the headgroup region. Interfacial dehydration may contribute to CO 2 -induced fluidization by altering headgroup interactions, surface packing density, and in turn, the local viscosity near the DPH probe.…”

Section: Resultsmentioning

confidence: 99%

Liposome Fluidization and Melting Point Depression by Pressurized CO₂ Determined by Fluorescence Anisotropy

et al. 2004

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The influence of CO2 on the bilayer fluidity of liposomes, which are representative of model cellular membranes, was examined for the first time at the elevated pressures (up to 13.9 MPa) associated with CO2-based processing of liposomes and microbial sterilization. Fluidization and melting point depression of aqueous dipalmitoylphosphatidylcholine (DPPC) liposomes by pressurized CO2 (present as an excess phase) were studied by steady-state fluorescence anisotropy using the membrane probe 1,6-diphenyl-1,3,5-hexatriene (DPH). Isothermal experiments revealed reversible, pressure-dependent fluidization of DPPC bilayers at temperatures corresponding to near-gel (295 K) and fluid (333 K) phases at atmospheric pressure, where the gel-to-fluid phase transition (Tm) occurs at approximately 315 K. Isobaric measurements (PCO2 =1.8, 7.0, and 13.9 MPa) of DPH anisotropy demonstrate substantial melting point depression (DeltaTm = -4.8 to -18.5 K) and a large broadening of the gel-fluid phase transition region, which were interpreted using conventional theories of melting point depression. Liposome fluidity is influenced by CO2 accumulation in the hydrocarbon core and polar headgroup region, as well as the formation of carbonic acid and/or the presence of buffering species under elevated CO2 pressure.

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“…The physical state of the lipids can be changed by desaturation and elongation, cyclization of fatty acids, their cis/trans isomerization and by the incorporation of branched fatty acids into phospholipids (Sajbidor, 1997). These processes can be induced by changes in the temperature, by addition of drugs and anaesthetics and also by changes in the extracellular environment (Sajbidor, 1997;Brockerhoff, 1982). Here, the medium pH, ethanol stress, osmotic pressure and salt stress are important factors (Drici Cachon et al, 1996;Gaxiola et al, 1996;Russell et al, 1995;Piper, 1995).…”

Section: Discussionmentioning

confidence: 99%

Differences in the fatty acid composition of KB‐cells and gingival keratinocytes is culture medium additive dependent

Pelz

Hopfener

Wiedmann-Al-Ahmad

et al. 2006

Biomedical Chromatography

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The influence of culture medium additives foetal bovine serum (FBS), serum effective substitutes (SES) and human autologous serum on the fatty acid profile of KB-cells and human gingival keratinocytes was examined. The KB-cells were cultivated in RPMI medium added with FBS or SES and the gingival keratinocytes in D-MEM added with FBS or human autologous serum. Two days before the cells were prepared for gas chromatography (GC), the media were changed to serum- and antibiotic-free media. Whole fatty acids of the cells were analysed using GC and the fatty acid profiles were compared. KB-cells as well as gingival keratinocytes changed their fatty acid composition, according to the medium additive used. Significant differences were observed. In the case of KB-cells cultivated with SES the fatty acid changes suggest an increase of the membrane fluidity. Corresponding and significant differences were observed with gingival keratinocytes cultivated in medium added with human autologous serum: the membrane fluidity of the gingival keratinocytes was increased. It is supposed that an increased membrane fluidity caused by a different fatty acid spectrum of the host cell may relate to mechanisms of bacterial adhesion. Consequently, in vitro studies on invasion and adhesion of bacteria or virus are dependent on the medium used. Further analyses are necessary of the functional effects caused by differences in the content of specific FAs, especially with regard to the application of cultivated cells in the field of tissue engineering.

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Anesthetics may restructure the hydrogen belts of membranes

Cited by 27 publications

References 17 publications

Effects of Ethanol on Lipid Bilayers Containing Cholesterol, Gangliosides, and Sphingomyelin

Effects of Ethanol on Lipid Bilayers Containing Cholesterol, Gangliosides, and Sphingomyelin

Liposome Fluidization and Melting Point Depression by Pressurized CO₂ Determined by Fluorescence Anisotropy

Differences in the fatty acid composition of KB‐cells and gingival keratinocytes is culture medium additive dependent

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Anesthetics may restructure the hydrogen belts of membranes

Cited by 27 publications

References 17 publications

Effects of Ethanol on Lipid Bilayers Containing Cholesterol, Gangliosides, and Sphingomyelin

Effects of Ethanol on Lipid Bilayers Containing Cholesterol, Gangliosides, and Sphingomyelin

Liposome Fluidization and Melting Point Depression by Pressurized CO2 Determined by Fluorescence Anisotropy

Differences in the fatty acid composition of KB‐cells and gingival keratinocytes is culture medium additive dependent

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Liposome Fluidization and Melting Point Depression by Pressurized CO₂ Determined by Fluorescence Anisotropy