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Alobeedallah H, Cornell B, Ghazal M, Coster H. The Effect of Benzyl Alcohol on the Voltage-Current Characteristics of Tethered Lipid Bilayers. J Membr Biol 2023; 256:423-431. [PMID: 37728833 DOI: 10.1007/s00232-023-00291-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2022] [Accepted: 08/21/2023] [Indexed: 09/21/2023]
Abstract
In this study a lipid bilayer membrane model was used in which the bilayer is tethered to a solid substrate with molecular tethers. Voltage-current (V-I) measurements of the tethered bilayer membranes (tBLM) and tBLM with benzyl alcohol (BZA) incorporated in their structures, were measured using triangular voltage ramps of 0-500 mV. The temperature dependence of the conductance deduced from the V-I measurements are described. An evaluation of the activation energies for electrical conductance showed that BZA decreased the activation/ Born energies for ionic conduction of tethered lipid membranes. It is concluded that BZA increased the average pore radius of the tBLM.
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Affiliation(s)
- Hadeel Alobeedallah
- Department of Electrical, Computer and Biomedical Engineering, Abu Dhabi University, Abu Dhabi, United Arab Emirates.
| | - Bruce Cornell
- SDx Tethered Membranes Pty Ltd, Roseville, Sydney, 2069, Australia
| | - Mohammed Ghazal
- Department of Electrical, Computer and Biomedical Engineering, Abu Dhabi University, Abu Dhabi, United Arab Emirates
| | - Hans Coster
- School of Chemical and Biomolecular Engineering, The University of Sydney, Sydney, 2006, Australia
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2
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Himbert S, Zhang L, Alsop RJ, Cristiglio V, Fragneto G, Rheinstädter MC. Anesthetics significantly increase the amount of intramembrane water in lipid membranes. SOFT MATTER 2020; 16:9674-9682. [PMID: 32869047 DOI: 10.1039/d0sm01271h] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
The potency of anesthesia was directly linked to the partitioning of the drug molecules in cell membranes by Meyer and Overton. Many molecules interact with lipid bilayers and lead to structural and functional changes. It remains an open question which change in membrane properties is responsible for a potential anesthetic effect or if anesthetics act by binding to direct targets. We studied the effect of ethanol, diethyl ether and isoflurane on the water distribution in lipid bilayers by combining all-atom molecular dynamics simulations and neutron diffraction experiments. The simulations show strong membrane-drug interactions with partitioning coefficients of 38%, 92% and 100% for ethanol, diethyl ether and isoflurane, respectively, and provide evidence for an increased water partitioning in the membrane core. The amount of intramembrane water molecules was experimentally determined by selectively deuterium labeling lipids, anesthetic drug and water molecules in neutron diffraction experiments. Four additional water molecules per lipid were observed in the presence of ethanol. Diethyl ether and isoflurane were found to significantly increase the amount of intramembrane water by 25% (8 water molecules). This increase in intramembrane water may contribute to the non-specific interactions between anesthetics and lipid membranes.
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Affiliation(s)
- Sebastian Himbert
- Department of Physics and Astronomy, McMaster University, ABB-241, 1280 Main Street West, Hamilton, Ontario L8S 4M1, Canada.
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3
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Mironov KS, Shumskaya M, Sidorov RA, Trofimova MS, Los DA. Membrane physical state and stress regulation in Synechocystis: fluidizing alcohols repress fatty acid desaturation. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2018; 96:1007-1017. [PMID: 30194781 DOI: 10.1111/tpj.14086] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/05/2018] [Revised: 09/01/2018] [Accepted: 09/03/2018] [Indexed: 05/16/2023]
Abstract
Cyanobacteria are prokaryotic photosynthetic organisms widely used in biotechnology, photosynthesis and abiotic stress research. There are several cyanobacterial strains modified to produce biofuels, but the influence of alcohols on cyanobacterial cell physiology is poorly understood. Here, we conducted a systematic study of the effects of nine primary aliphatic alcohols and an aromatic benzyl alcohol on both membrane physical state and the expression of genes for fatty acid desaturases (FADs) in a model cyanobacterium Synechocystis sp. strain PCC 6803. Hexan-1-ol was found to have the most membrane fluidizing action among all alcohols studied, with its efficiency correlating with both duration of treatment and alcohol concentration. A prolonged exposure to alcohol results in a continuous loss of unsaturated fatty acids (FAs) followed by cell death, an undesired challenge that should be considered in cyanobacterial biotechnology. We suggest that membrane fluidization is the key component in alcohol stress causing inactivation of FADs and resulting in a lethal depletion of unsaturated FAs. Due to the most pronounced effects of alcohol- and heat-induced membrane fluidization on desB encoding a terminal ω3-FAD, we propose to call desB a 'viscosity gene' in analogy to heat-induced 'fluidity gene' hspA.
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Affiliation(s)
- Kirill S Mironov
- Department of Molecular Biosystems, K.A. Timiryazev Institute of Plant Physiology, Russian Academy of Science, Botanicheskaya Street 35, Moscow, 127276, Russia
| | - Maria Shumskaya
- Department of Biology, School of Natural Sciences, Kean University, 1000 Morris Ave, Union, NJ, 07083, USA
| | - Roman A Sidorov
- Department of Molecular Biosystems, K.A. Timiryazev Institute of Plant Physiology, Russian Academy of Science, Botanicheskaya Street 35, Moscow, 127276, Russia
| | - Marina S Trofimova
- Department of Molecular Biosystems, K.A. Timiryazev Institute of Plant Physiology, Russian Academy of Science, Botanicheskaya Street 35, Moscow, 127276, Russia
| | - Dmitry A Los
- Department of Molecular Biosystems, K.A. Timiryazev Institute of Plant Physiology, Russian Academy of Science, Botanicheskaya Street 35, Moscow, 127276, Russia
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4
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Fábián B, Sega M, Voloshin VP, Medvedev NN, Jedlovszky P. Lateral Pressure Profile and Free Volume Properties in Phospholipid Membranes Containing Anesthetics. J Phys Chem B 2017; 121:2814-2824. [DOI: 10.1021/acs.jpcb.7b00990] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Balázs Fábián
- Department of Inorganic
and Analytical Chemistry, Budapest University of Technology and Economics, Szent Gellért tér 4, H-1111 Budapest, Hungary
- Institut UTINAM (CNRS UMR 6213), Université Bourgogne Franche-Comté, 16 route de Gray, F-25030 Besançon, France
| | - Marcello Sega
- Faculty of
Physics, University of Vienna, Sensengasse 8/9, A-1090 Vienna, Austria
| | - Vladimir P. Voloshin
- Institute of Chemical Kinetics and Combustion, Siberian Branch of the Russian Academy of Sciences (SB RAS), Novosibirsk 630090, Russia
| | - Nikolai N. Medvedev
- Novosibirsk State University, Novosibirsk 630090, Russia
- Institute of Chemical Kinetics and Combustion, Siberian Branch of the Russian Academy of Sciences (SB RAS), Novosibirsk 630090, Russia
| | - Pál Jedlovszky
- Department of Chemistry, Eszterházy Károly University, Leányka utca 6, H-3300 Eger, Hungary
- MTA-BME Research Group of Technical Analytical Chemistry, Szent Gellért tér
4, H-1111 Budapest, Hungary
- Laboratory of Interfaces and Nanosize Systems,
Institute of Chemistry, Eötvös Loránd University, Pázmány Peter Stny 1/A, H-1117 Budapest, Hungary
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5
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Alobeedallah H, Cornell B, Coster H. The Effect of Benzyl Alcohol on the Dielectric Structure of Lipid Bilayers. J Membr Biol 2016; 249:833-844. [PMID: 27803961 DOI: 10.1007/s00232-016-9934-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2016] [Accepted: 10/22/2016] [Indexed: 11/25/2022]
Abstract
Molecularly tethered lipid bilayer membranes were constructed on a commercially available chemically modified gold substrate. This is a new and promising product that has allowed the construction of very robust lipid bilayers. Very high resolution electrical impedance spectroscopy (EIS) was used to determine the dielectric structure of the lipid bilayers and associated interfaces. The EIS data were modelled in terms of the dielectric substructure using purpose developed software. The hydrophobic region, where the lipid tails are located, was revealed by the EIS in the frequency range of (1-100) Hz and its thickness was calculated from the capacitance of this region and found to be approximately 3-4 nm. The hydrophilic region, where the polar heads are located, was revealed at higher frequencies and its thickness was estimated to be approximately 1-2 nm. The effect of the local anaesthetic benzyl alcohol (BZA) on the tethered lipid bilayers was investigated. The effect of BZA on the membrane capacitance and conductance allowed the changes in the thickness of the polar head and hydrophobic tails regions to be determined. It was found that the addition of BZA caused a significant increase in the capacitance (corresponding to a decrease in the thickness) of the hydrophobic region and an increase in the membrane electrical conductance. The EIS allowed a distinction between a hydrophobic region in the centre of the bilayer and an outer hydrophobic region. Benzyl alcohol was found to have the largest effect on the outer, hydrophobic region, although the inner hydrophobic region was also consistently affected.
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Affiliation(s)
- Hadeel Alobeedallah
- School of Chemical and Biomolecular Engineering, The University of Sydney, Sydney, NSW, 2006, Australia.
| | - Bruce Cornell
- SDx Tethered Membranes Pty Ltd., Roseville, Sydney, NSW, 2069, Australia
| | - Hans Coster
- School of Chemical and Biomolecular Engineering, The University of Sydney, Sydney, NSW, 2006, Australia
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6
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Fábián B, Darvas M, Picaud S, Sega M, Jedlovszky P. The effect of anaesthetics on the properties of a lipid membrane in the biologically relevant phase: a computer simulation study. Phys Chem Chem Phys 2015; 17:14750-60. [DOI: 10.1039/c5cp00851d] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Phospholipid membranes containing four different general anaesthetic molecules are simulated in the biologically relevant Lα phase at atmospheric and high pressures.
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Affiliation(s)
- Balázs Fábián
- Laboratory of Interfaces and Nanosize Systems
- Institute of Chemistry
- Eötvös Loránd University
- H-1117 Budapest
- Hungary
| | - Mária Darvas
- SISSA
- Sector of Molecular and Statistical Biophysics
- 34136 Trieste
- Italy
| | - Sylvain Picaud
- Institut UTINAM (CNRS UMR 6213)
- Université de Franche-Comté
- F-25030 Besançon
- France
| | - Marcello Sega
- Institut für Computergestützte Biologische Chemie
- University of Vienna
- A-1090 Vienna
- Austria
| | - Pál Jedlovszky
- Laboratory of Interfaces and Nanosize Systems
- Institute of Chemistry
- Eötvös Loránd University
- H-1117 Budapest
- Hungary
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7
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Antony A, Chilcott T, Coster H, Leslie G. In situ structural and functional characterization of reverse osmosis membranes using electrical impedance spectroscopy. J Memb Sci 2013. [DOI: 10.1016/j.memsci.2012.09.028] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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8
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Darvas M, Hoang PNM, Picaud S, Sega M, Jedlovszky P. Anesthetic molecules embedded in a lipid membrane: a computer simulation study. Phys Chem Chem Phys 2012; 14:12956-69. [DOI: 10.1039/c2cp41581j] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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9
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López Cascales JJ, Huertas ML, García de la Torre J. Molecular dynamics simulation of a dye molecule in the interior of a bilayer: 1,6-diphenyl-1,3,5-hexatriene in dipalmitoylphosphatidylcholine. Biophys Chem 2007; 69:1-8. [PMID: 17029914 DOI: 10.1016/s0301-4622(96)02267-3] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/1996] [Accepted: 11/22/1996] [Indexed: 12/31/2022]
Abstract
A molecular dynamics simulation was carried out for a dipalmitoylphosphatidylcholine (DPPC) membrane in its liquid crystalline state containing different concentrations of the dye molecule 1,6-diphenyl-1,3,5-hexatriene (DPH). From a numerical analysis of the trajectories, we obtained information concerning structural changes of the membrane due to the presence of the probe and some hydrodynamic information concerning the probe itself. The hydrodynamic properties regarding dye molecules that have been reported in this article are: rotational and translational diffusion coefficient and relaxation times. From this analysis, we estimated a range of values of 0.6-0.9 cP for the micro-viscosity in the mid-membrane. These simulations also afforded us some information regarding structural changes in the membrane as a consequence of the presence of the fluorescent dyes at different concentrations. Thus, the disorder inside the membrane, the surface area per lipid and thickness of the membrane were also investigated.
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Affiliation(s)
- J J López Cascales
- Departamento de Química Física, Universidad de Murcia, Campus de Espinardo 30071, Murcia, Spain
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10
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Dielectric and Electrical Properties of Lipid Bilayers in Relation to their Structure. ACTA ACUST UNITED AC 2003. [DOI: 10.1016/s0927-5193(03)80026-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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11
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Bhattacharya S, Haldar S. Interactions between cholesterol and lipids in bilayer membranes. Role of lipid headgroup and hydrocarbon chain-backbone linkage. BIOCHIMICA ET BIOPHYSICA ACTA 2000; 1467:39-53. [PMID: 10930507 DOI: 10.1016/s0005-2736(00)00196-6] [Citation(s) in RCA: 145] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
We have employed four lipids in the present study, of which two are cationic and two bear phosphatidylcholine (PC) headgroups. Unlike dipalmitoylphosphatidylcholine, the other lipids employed herein do not have any ester linkage between the hydrocarbon chains and the respective lipid backbones. Small unilamellar vesicles formed from each of the PC and cationic lipids with or without varying amounts of cholesterol have been examined using the steady-state fluorescence anisotropy method as a function of temperature. The anisotropy data clearly indicate that the order in the lipid bilayer packing is strongly affected upon inclusion of cholesterol. This effect is similar irrespective of the electrostatic character of the lipid employed. The influence of cholesterol inclusion on multi-lamellar lipid dispersions has also been examined by 1H-nuclear magnetic resonance spectroscopy above the phase transition temperatures. With all the lipids, the line widths of (CH2)n protons of hydrocarbon chains in the NMR spectra respond to the addition of cholesterol to membranes. The influence on the bilayer widths of various lipids upon inclusion of cholesterol was determined from X-ray diffraction studies of the cast films of the lipid-cholesterol coaggregates in water. The effect of cholesterol on the efflux rates of entrapped carboxyfluorescein (CF) from the phospholipid vesicles was determined. Upon incremental incorporation of cholesterol into the phospholipid vesicles, the CF leakage rates were progressively reduced. Independent experiments measuring transmembrane OH- ion permeation rates from cholesterol-doped cationic lipid vesicles using entrapped dye riboflavin also demonstrated that the addition of cholesterol into the cationic lipid vesicles reduced the leakage rates irrespective of lipid molecular structure. It was found that the cholesterol induced changes on the membrane properties such as lipid order, linewidth broadening, efflux rates, bilayer widths, etc., did not depend on the ability of the lipids to participate in the hydrogen bonding interactions with the 3beta-OH of cholesterol. These findings emphasize the importance of hydrophobic interaction between lipid and cholesterol and demonstrate that it is not necessary to explain the observed cholesterol induced effects on the basis of the presence of hydrogen bonding between the 3beta-OH of cholesterol and the lipid chain-backbone linkage region or headgroup region.
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Affiliation(s)
- S Bhattacharya
- Department of Organic Chemistry, Indian Institute of Science, Bangalore.
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12
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Moskvina E, Imre EM, Ruis H. Stress factors acting at the level of the plasma membrane induce transcription via the stress response element (STRE) of the yeast Saccharomyces cerevisiae. Mol Microbiol 1999; 32:1263-72. [PMID: 10383766 DOI: 10.1046/j.1365-2958.1999.01438.x] [Citation(s) in RCA: 48] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
A variety of stress factors induces transcription via the stress response element (STRE) present in control regions of a number of genes of the yeast Saccharomyces cerevisiae. Induction of transcription involves nuclear translocation of the STRE-binding transcription activators Msn2p and Msn4p. The primary cellular events triggering this translocation are presently not well understood. In this investigation, we have observed that a number of factors acting at the level of the yeast plasma membrane, including the antifungal agent nystatin, the steroidal alkaloid tomatine, benzyl alcohol, a number of detergents and the plasma membrane H+-ATPase inhibitor diethylstilbestrol or mutations in the PMA1 gene encoding the plasma membrane ATPase, induce Msn2p nuclear accumulation and STRE-dependent transcription. At least some of the stress factors acting via STREs cause an increase in plasma membrane permeability, leading to a decrease in membrane potential, which might be a primary cellular stress signal. A decrease in internal pH triggered by permeabilization of the plasma membrane or a change in cAMP levels are at least not obligatory factors in intracellular stress signal transduction. The signal transduction pathway transmitting the signal generated at the plasma membrane to Msn2p is still unknown.
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Affiliation(s)
- E Moskvina
- Vienna Biocenter, Institut für Biochemie und Molekulare Zellbiologie der Universität Wien and Ludwig Boltzmann-Forschungsstelle für Biochemie, Dr Bohrgasse 9, A-1030 Vienna, Austria
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13
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Chilcott TC, Coster HG. Electrical impedance tomography study of biological processes in a single cell. Ann N Y Acad Sci 1999; 873:269-86. [PMID: 10372176 DOI: 10.1111/j.1749-6632.1999.tb09475.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
An in vivo electrical impedance tomography (EIT) study of single plant cells of Chara corallina is reported. When these aquatic cells grow in alkaline conditions, proton-translocating ATP synthases in the plasma membrane operate in reverse, utilizing ATP to translocate protons against an electrochemical gradient to the periplasm and creating localized acidic regions along the cell's cylindrical surface. These acidic regions, which appear as radial bands, approximately 5 mm long, between narrower alkaline bands, facilitate the uptake of bicarbonate, the plant's source of inorganic carbon for photosynthesis in the carbon dioxide-depleted alkaline conditions. Our EIT study of cell ultrastructure in the acidic and alkaline regions provides evidence that the plasma membrane is folded in localized regions (e.g., charasomes) in the acidic bands. The very low frequency capacitance dispersions were very similar to those of double fixed-charge structures. Such charge distributions are known to be present in the membrane-bound F0 portion of the ATP synthase. The theoretical dependence of the fixed-charge concentrations on pH in the proteins is shown to broadly account for the observed correlations between pH, membrane potential, conductance, and capacitance in these regions. In synthetically formed double fixed-charge membranes, electric field-induced dissociation of water into H+ and OH- occurs. This leads to the speculation that H+/OH- fluxes in ATP synthases located in the alkaline regions of Chara cells might also involve the electric field-induced dissociation of water.
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Affiliation(s)
- T C Chilcott
- UNESCO Center for Membrane Science and Technology, School of Physics, University of New South Wales, Sydney, Australia
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14
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Karolis C, Coster HG, Chilcott TC, Barrow KD. Differential effects of cholesterol and oxidised-cholesterol in egg lecithin bilayers. BIOCHIMICA ET BIOPHYSICA ACTA 1998; 1368:247-55. [PMID: 9459602 DOI: 10.1016/s0005-2736(97)00180-6] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Low frequency impedance measurements of pure egg lecithin (phosphatidylcholine) bilayers have revealed the presence of four layers which can be attributed to the acyl chain, carbonyl, glycerol bridge and phosphatidylcholine regions of the lecithin molecule. Measurements on bilayers formed in the presence of unoxidised-cholesterol revealed that cholesterol molecules were located in the hydrocarbon region of the bilayer with its hydroxyl groups aligned with the carbonyl region of the lecithin molecules. Measurements of oxidised-cholesterol lecithin bilayers revealed that these molecules protruded less into the hydrocarbon region and their polar hydroxyl group aligned with the glycerol bridge region of the lecithin molecule.
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Affiliation(s)
- C Karolis
- UNESCO Centre for Membrane Science and Technology and Department of Biophysics, School of Physics, University of New South Wales, Sydney, Australia
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15
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López Cascales JJ, Hernández Cifre JG, García de la Torre J. Anaesthetic Mechanism on a Model Biological Membrane: A Molecular Dynamics Simulation Study. J Phys Chem B 1998. [DOI: 10.1021/jp9714532] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- J. J. López Cascales
- Departamento de Química Física, Universidad de Murcia, Campus de Espinardo 30071, Murcia, Spain
| | - J. G. Hernández Cifre
- Departamento de Química Física, Universidad de Murcia, Campus de Espinardo 30071, Murcia, Spain
| | - J. García de la Torre
- Departamento de Química Física, Universidad de Murcia, Campus de Espinardo 30071, Murcia, Spain
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16
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Dei L, Ferroni E, Sarti G. Effect of halothane on the electrical properties of mixed bilayers of glycerol monooleate andl,α-dipalmitoylphosphatidylcholine. Colloids Surf B Biointerfaces 1995. [DOI: 10.1016/0927-7765(94)01184-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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17
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18
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Iiyama S, Suezaki Y, Toko K, Murata T, Kamaya H, Ueda I, Yamafuji K. Effect of local anesthetics on the electrical characteristics of an excitable model membrane composed of dioleyl phosphate. Biophys Chem 1990; 36:141-7. [PMID: 17056429 DOI: 10.1016/0301-4622(90)85017-z] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/1989] [Revised: 11/23/1989] [Accepted: 12/19/1989] [Indexed: 10/18/2022]
Abstract
The local anesthetics, tetracaine, procaine and lidocaine, interacted with a negatively charged lipid membrane composed of dioleyl phosphate (DOPH), which exhibited a self-sustained oscillation of the membrane potential. The anesthetics depolarized the membrane potential when present in increasing concentrations, whereas they increased the membrane resistance at low concentrations and decreased it at high concentrations. The above results were analyzed on the basis of electrochemical theory taking into account ion flux across the membrane. The electrical characteristics are affected by both the hydrophobicity and the diffusion constant of local anesthetics within the membrane.
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Affiliation(s)
- S Iiyama
- Department of Home Economics, Kyushu Junior College of Kinki University, Iizuka 820, Japan
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19
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Brockerhoff H, Zingoni J, Brockerhoff S. Mechanism of anesthesia: Anesthetics may restructure the hydrogen belts of membranes. Neurochem Int 1990; 17:15-9. [DOI: 10.1016/0197-0186(90)90062-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/1989] [Accepted: 12/18/1989] [Indexed: 12/16/2022]
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20
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Elliott JR, Haydon DA. The actions of neutral anaesthetics on ion conductances of nerve membranes. BIOCHIMICA ET BIOPHYSICA ACTA 1989; 988:257-86. [PMID: 2541793 DOI: 10.1016/0304-4157(89)90021-x] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Affiliation(s)
- J R Elliott
- Department of Anatomy and Physiology, Old Medical School, University, Dundee U.K
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21
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Gruber HJ, Low PS. Interaction of amphiphiles with integral membrane proteins. I. Structural destabilization of the anion transport protein of the erythrocyte membrane by fatty acids, fatty alcohols, and fatty amines. BIOCHIMICA ET BIOPHYSICA ACTA 1988; 944:414-24. [PMID: 3179297 DOI: 10.1016/0005-2736(88)90512-3] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
The effect of model amphiphiles on the structural stability of the anion exchange protein (band 3) of the human erythrocyte membrane was studied by differential scanning calorimetry. The concentration of membranes, as well as the concentration, head group, alkyl chain length, degree of unsaturation, and double bond configuration of a variety of alkane derivatives were all varied in a systematic way. The depression of the denaturation temperature of band 3 per unit membrane concentration of the amphiphile was then determined in order to quantitate the potency of each drug. Saturated fatty acids of chain length C8 to C24 displayed a monotonic decrease in potency up to C20, followed by a dramatic diminution in potency at C22 and C24. Unsaturation caused only minor increases in the abilities of fatty acids to perturb the anion exchanger, and surprisingly, there was neither a trend for the number of double bonds nor a significant cis-trans distinction. Arachidonic acid, as an exception, was much more effective than any other amphiphile in destabilizing band 3. Fatty acids were about three times more potent than fatty amines and fatty alcohols; however, the enhanced partitioning of the latter into the membrane compensated at certain membrane/buffer ratios for its reduced intrinsic potency. A quantitative model interpretation of the data is presented in an accompanying paper.
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Affiliation(s)
- H J Gruber
- Department of Chemistry, Purdue University, West Lafayette, IN
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22
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Depauw H, De Wolf M, Van Dessel G, Hilderson H, Lagrou A, Dierick W. Fluidity of thyroid plasma membranes. Subcell Biochem 1988; 13:193-240. [PMID: 2577855 DOI: 10.1007/978-1-4613-9359-7_6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
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23
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Albrecht RF, Miletich DJ. Speculations on the molecular nature of anesthesia. GENERAL PHARMACOLOGY 1988; 19:339-46. [PMID: 3046995 DOI: 10.1016/0306-3623(88)90026-2] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Affiliation(s)
- R F Albrecht
- Department of Anaesthesiology, Michael Reese Hospital and Medical Center, Chicago, IL 60616
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24
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Coster HG, Laver DR. The effect of benzyl alcohol and cholesterol on the acyl chain order and alkane solubility of bimolecular phosphatidylcholine membranes. BIOCHIMICA ET BIOPHYSICA ACTA 1986; 861:406-12. [PMID: 3768354 DOI: 10.1016/0005-2736(86)90448-7] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
An investigation was made of the effects of cholesterol and benzyl alcohol on the partitioning of n-alkanes between lipid bilayer membranes and bulk lipid/alkane solutions (in the torus). Bilayers were formed from solutions containing alkanes of different chain lengths, together with phosphatidylcholine and cholesterol in varying proportions. The partitioning of the alkanes was determined from measurements of the very low frequency (1 Hz) capacitance of the membranes. Perturbation of the internal membrane structure by the inclusion of cholesterol and benzyl alcohol produced very significant changes in the n-alkane partition coefficient, cholesterol causing a decrease and benzyl alcohol an increase in the alkane partitioning into the bilayer. A correlation exists between the effects of these compounds on the alkane partitioning and their effect on the segmental chain order of the acyl chains in the bilayer and this correlation is consistent with a statistical-mechanical model of the lipid/alkane bilayers in the liquid crystalline state. The perturbation by cholesterol and benzyl alcohol of the internal structure of membranes bears on the conflicting reports of the effects of these substances on artificial lipid bilayers and could also be relevant to their known physiological effects.
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Yoshida T, Kamaya H, Ueda I. Giant planar lipid bilayer. III. Maxwell—Wagner impedance dispersion and anesthetic effects upon interfacial capacitance. J Colloid Interface Sci 1985. [DOI: 10.1016/0021-9797(85)90355-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Ruderman G, Jennings BR, Dean RT. Electric birefringence as a means of studying the effect of anaesthetics on liposomes. BIOCHIMICA ET BIOPHYSICA ACTA 1984; 776:60-4. [PMID: 6477903 DOI: 10.1016/0005-2736(84)90250-5] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Birefringence can be induced in liposome suspensions using electric fields. The fields interact predominantly with anisotropic electrical polarisabilities which give rise to induced dipole moments. Using pulsed electric fields, the optical and electrical polarisabilities and the geometrical size of the liposomes can be measured simultaneously. These parameters have been found to be very sensitive to the presence of small amounts of fluidising additives of polar and ionic nature. Illustrative data are presented for the influence of the amines ammonium chloride, methyl ammonium chloride and lignocaine and of benzyl alcohol on phosphatidylcholine/serine liposomes. Structural changes in the vesicle membranes were detected, which appeared to correlate with the biological functions, thus indicating that electric birefringence is a rapid and useful method for studying interactive phenomena in lipid membrane systems.
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Abstract
Benzyl alcohol caused a rather complete and selective inhibition of the methylamine sensitive (i.e., the putative lysosomal) pathway of protein degradation in isolated rat hepatocytes. The effect was found to be entirely reversible within 30 min of removing the agent. A morphometric examination of electron micrographs revealed that the inhibition of lysosomal protein degradation coincided with a block in the formation of autophagic vacuoles. The number of acidic vacuoles (i.e., vacuoles induced to swell by adding methylamine) was not drastically reduced.
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Abstract
Important constraints on possible molecular mechanisms of general anaesthesia are derived from a quantitative reappraisal of data on the potency of general anaesthetics on whole animals. Despite their popularity, theories that invoke lipids as the prime target do not look at all promising, and available data point much more plausibly to a direct effect on particularly sensitive proteins. Structural changes of proteins on binding general anaesthetics are probably small but may be sufficient to perturb normal function; alternatively, anaesthetics may compete with an endogenous ligand. The phenomenon of pressure reversal of anaesthesia may simply be due to anaesthetics being squeezed away from their target sites.
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Mitranic MM, Boggs JM, Moscarello MA. The effect of linoleic acid and benzyl alcohol on the activity of glycosyltransferases of rat liver Golgi membranes and some soluble glycosyltransferases. BIOCHIMICA ET BIOPHYSICA ACTA 1982; 693:75-84. [PMID: 6217837 DOI: 10.1016/0005-2736(82)90472-2] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
The effects of the membrane perturbing reagents linoleic acid and benzyl alcohol on the activities of four rat liver Golgi membrane enzymes, N-acetylglucosaminyl-, N-acetylgalactosaminyl-, galactosyl-, and sialyltransferases and several soluble glycosyltransferases, bovine milk galactosyl- and N-acetylglucosaminyltransferases and porcine submaxillary N-acetylgalactosaminyltransferases have been studied. In rat liver Golgi membranes, linoleic acid inhibited the activities of N-acetylgalactosaminyl- and galactosyltransferases by 50% or greater, sialyltransferase by 10-15%, and N-acetylglucosaminyltransferase not at all. The isolated bovine milk N-acetylglucosaminyltransferase and porcine submaxillary N-acetylgalactosylaminyltransferase were not inhibited but bovine milk galactosyltransferase was inhibited by 95% or greater. The inhibition by linoleic acid on Golgi membrane galactosyltransferase appears to be a direct effect of the reagent on the enzyme. Incorporation of bovine milk galactosyltransferase into liposomes formed from saturated phospholipids, DMPC, DPPC, and DSPC (dimyristoyl-, dipalmitoyl-, and distearoylphosphatidylcholine) prevented inhibition of the enzyme activity suggesting that the lipid formed a barrier which did not allow linoleic acid access to the enzyme. The water soluble benzyl alcohol was more effective in inhibiting enzymes of the isolated rat liver Golgi complex. All four glycosyltransferases were inhibited, the N-acetylglucosaminyl- and N-acetylgalactosaminyltransferases by more than 95%. A higher concentration of benzyl alcohol was necessary to inhibit the galactosyltransferases than was required for the other Golgi enzymes. Benzyl alcohol also inhibited the isolated bovine milk N-acetylglucosaminyl- and galactosyltransferases 90% to 95%, respectively, but did not affect the isolated porcine submaxillary gland N-acetylgalactosaminyltransferase. Benzyl alcohol did not inhibit the milk galactosyltransferase incorporated into DMPC or DPPC liposomes but showed a complex effect on the activity of the enzyme incorporated into DSPC vesicles, a stimulation of activity at low concentrations followed by an inhibition. A lipid environment consisting of saturated lipids appears to present a barrier to inhibiting substances such as linoleic acid and benzyl alcohol, or lipid may stabilize the active conformation of the enzyme. The different effects of these reagents on four transferases of the Golgi complex suggest that the lipid environment around these enzymes may be different for each transferase.
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Brockerhoff H. Anesthetics may restructure the hydrogen belts of membranes. Lipids 1982; 17:1001-3. [DOI: 10.1007/bf02534599] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/1982] [Indexed: 10/23/2022]
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Shibata T, Sugiura Y, Iwayanagi S. Effects of benzyl alcohol on phosphatidylcholine lamellar phase with different water contents. Chem Phys Lipids 1982; 31:105-16. [PMID: 7139844 DOI: 10.1016/0009-3084(82)90037-8] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Effects of benzyl alcohol (BA) on the bilayer thickness dl and the fluidity of egg phosphatidylcholine (PC) lamellar phase with various water contents have been studied by X-ray diffraction and the proton spin-lattice relaxation rate. At lower water contents, BA causes dl to decrease and the rate of molecular motions to increase. By contrast, with increasing BA at excess water, dl remains nearly unchanged, though the rate of motions increases. Hydration experiment for egg phosphatidylcholine lamellae with BA at a 1 : 1 molar ratio shows that in the range from 15% to 30% water, dl decreases to the value of the fully hydrated sample without BA and is nearly constant above 30% water. The value at full hydration is suggested to be a lower limit of the bilayer thickness, the chain is in the unperturbed state. It is in an extended structure at lower water contents. This leads to the difference in the effect of BA on the bilayer thickness at different water contents.
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Salah KM, Hampton KK, Findlay JB. The effects of general anaesthetics on glucose and phosphate transport across the membrane of the human erythrocyte. BIOCHIMICA ET BIOPHYSICA ACTA 1982; 688:163-8. [PMID: 7093272 DOI: 10.1016/0005-2736(82)90591-0] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
A study has been carried out into the effects of clinically important general anaesthetics, althesin, thiopentone and propanidid, on the transport of glucose and phosphate across the membrane of the human erythrocyte. In general these three substances all inhibit both transport processes but with characteristic inhibition profiles and varying degrees of efficacy. Glucose transport was more sensitive to the hydrophobic steroids and phosphate transport to propanidid. Some hydrophobic agents, e.g., iodobenzene and its azide, were not inhibitory. Removal of cholesterol to some extent augmented the inhibitory effects of most of these compounds (not propanidid). It is argued that these effects are due to the penetration of the anaesthetics into the lipid bilayer and either subsequent disruption of the lipid annuli surrounding the integral membrane proteins and/or direct anaesthetic-protein interaction.
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Rosenberg PH, Alila A. Hydrophobic membrane interaction of etidocaine, bupivacaine and 2-chloroprocaine. A spin and fluorescent probe study. NAUNYN-SCHMIEDEBERG'S ARCHIVES OF PHARMACOLOGY 1982; 319:95-100. [PMID: 7110378 DOI: 10.1007/bf00503919] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
It has been suggested that local anesthetics may block sodium conductance through nervous membranes also by hydrophobic interaction, e.g., by expanding the membrane. Decreased anisotropy (fluidization) and depressed phase transition temperatures have been shown by relatively high local anesthetic concentrations. We studied the dose dependence of the effect of three clinically used local anesthetics, with different lipid solubility, on lipid fluidity parameters of four different model membranes. With stearic acid spin labels in dipalmitoyl lecithin vesicles etidocaine (1-5 mM) had the clearest fluidizing effect followed by bupivacaine (5 mM); 2-chloroprocaine was without effect on lipid fluidity. In synaptic plasma membranes a fluidizing effect near the hydrophilic part of the lipid bilayer was similar with etidocaine and bupivacaine (5-10 mM); 2-chloroprocaine had no effect. Bupivacaine at 125 and 250 muM had a small ordering effect, which was not seen at a more hydrophobic site of the membrane. Etidocaine had the strongest fluidizing effect at the latter site of the synaptic plasma membranes. In erythrocyte ghost membranes, probed by stearic acid spin labels near the hydrophilic end, none of local anesthetics affected fluidity at 24 degrees C, while at 37 degrees C etidocaine (1-5 mM) and bupivacaine (5 mM) had a fluidizing effect. Dimyristoyl lecithin vesicles were probed by cis- and trans-parinaric acid. Etidocaine and bupivacaine (5-10 mM) clearly depressed the phase transition temperature evaluated from fluorescence intensity scans. The effect was most marked with bupivacaine (1-10 mM) when cis-parinaric acid was used. While isolated mammalian nerves are blocked by local anesthetic concentrations below 100 muM, this study shows that the clinically used local anesthetics increase fluidity and depress phase transition temperature only at 10-100 times higher concentrations at physiological pH. This kind of hydrophobic membrane interaction may not be important for the nerve blocking effect.
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Boulanger Y, Schreier S, Smith IC. Molecular details of anesthetic--lipid interaction as seen by deuterium and phosphorus-31 nuclear magnetic resonance. Biochemistry 1981; 20:6824-30. [PMID: 6895602 DOI: 10.1021/bi00527a013] [Citation(s) in RCA: 165] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
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Bradley RJ, Urry DW, Parenti-Castelli G, Lenaz G. Effects of halothane on channel activity of N-acetyl gramicidin. Biochem Biophys Res Commun 1981; 101:963-9. [PMID: 6171278 DOI: 10.1016/0006-291x(81)91843-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
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Davio SR, Low PS. The effect of anesthetic charge on anesthetic-phospholipid interactions. BIOCHIMICA ET BIOPHYSICA ACTA 1981; 644:157-64. [PMID: 7260071 DOI: 10.1016/0005-2736(81)90371-0] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Cationic and uncharged forms of a tertiary amine local anesthetic are reported to have different properties and potencies as nerve blocking agents. However, the relative capacities of each form of the local anesthetic to perturb the properties of different model membrane systems is unknown. For this reason we have studied the effects of uncharged lidocaine (high pH) and its quaternary amine analogue (W49091) on the phase transition properties of DMPS, DPPE and DPPC liposomes using high-sensitivity differential scanning calorimetry. We report that neutral lidocaine interacts similarly with all three phospholipids. This interaction results in a decrease in the temperature of the gel leads to liquid crystalline phase transition (Tm), an increase in the enthalpy of the transition (delta H), and a slight decrease in the cooperativity of melting. Quaternary lidocaine (W49091), on the other hand, interacts significantly with only DMPS; the result being again a decrease in the temperature of DMPS melting, an increase in delta H, and a slight decrease in the cooperativity of the phase transition. These results are interpreted to indicate that uncharged lidocaine enters the membrane during the DPPE and DPPC phase transitions. In the case of DMPS, an influx of both charged forms of lidocaine must occur at Tm. These anesthetic fluxes at the lipid's phase transition are suggested to be responsible for the observed elevated enthalpies of the respective transitions. The observation that the cationic form of lidocaine does not significantly modify the behavior of DPPC and DPPE liposomes suggests that these lipids are not important components of the anesthetic's site in nerve membranes. However, the dramatic perturbation of the properties of DMPS by W49091 suggests that phosphatidylserine may comprise part of this inhibitory site.
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Caffrey M, Feigenson GW. Fluorescence quenching in model membranes. 3. Relationship between calcium adenosinetriphosphatase enzyme activity and the affinity of the protein for phosphatidylcholines with different acyl chain characteristics. Biochemistry 1981; 20:1949-61. [PMID: 6452902 DOI: 10.1021/bi00510a034] [Citation(s) in RCA: 184] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
The dependence of function and lipid binding affinity of an integral transport protein on the fatty acyl chain characteristics of a membrane-forming phospholipid have been determined. When a newly developed fluorescence quenching technique [London, E., & Feigenson, G. W. (1981) Biochemistry (first paper of three in this issue); London, E., & Feigenson, G. W. (1981) Biochemistry (preceding paper in this issue)] is used for examining lipid-protein interactions in membranes, the Ca2+ ATPase from rabbit sarcoplasmic reticulum is found to bind with equal affinity a large variety of phosphatidylcholines used to reconstitute the protein into enzymatically active vesicles, regardless of fatty acyl chain length or details of unsaturation. In parallel with the lipid binding studies, we have measured the sensitivity of the catalytic activity of the Ca2+ ATPase to the fatty acyl chain characteristics of the phosphatidylcholine membranes in which the enzyme was reconstituted. The enzyme appears to be sensitive only to the effective fatty acyl chain length, which determines the thickness of the bilayer in which the protein is inserted and displays little sensitivity to such details of unsaturation as degree, position, and isomeric type. Both ATP hydrolyzing and Ca2+ transporting activities of the enzyme were similarly affected by bilayer thickness, and maximum activity was observed in membranes of intermediate thickness. These observations are reconciled in a number of possible models for the manner in which this integral protein interacts with membranes of varying thickness. A freeze-thaw method was used to reconstitute the Ca2+ ATPase, and the vesicles so obtained have been characterized by gel permeation chromatography, density gradient centrifugation, and electron microscopy, (thin section). Convenient methods are described for (a) rapidly separating reconstituted Ca2+ ATPase from unincorporated protein simultaneously in a large number of small samples, giving good recovery of fractionated vesicles without significant dilution, and (b) measuring leakiness to Ca2+ of reconstituted vesicles. Additionally, the gel and liquid-crystal phase transition temperature and bilayer thickness have been determined respectively by differential thermal analysis and low-angle X-ray diffraction for some of the synthetic phosphatidylcholines, which range in chain length from 12 to 24 carbon atoms.
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Bean BP, Shrager P, Goldstein DA. Modification of sodium and potassium channel gating kinetics by ether and halothane. J Gen Physiol 1981; 77:233-53. [PMID: 6265590 PMCID: PMC2215432 DOI: 10.1085/jgp.77.3.233] [Citation(s) in RCA: 60] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
The effect of ether and halothane on the kinetics of sodium and potassium currents were investigated in the crayfish giant axon. Both general anesthetics produced a reversible, dose-dependent speeding up of sodium current inactivation at all membrane potentials, with no change in the phase of the currents. Double-pulse inactivation experiments with ether also showed faster inactivation, but the rate of recovery from inactivation at negative potentials was not affected. Ether shifted the midpoint of the steady-state fast inactivation curve in the hyperpolarizing direction and made the curve steeper. The activation of potassium currents was faster with ether present, with no change in the voltage dependence of steady-state potassium currents. Ether and halothane are known to perturb the structure of lipid bilayer membranes; the alterations in sodium and potassium channel gating kinetics are consistent with the hypothesis that the rates of the gating processes of the channels can be affected by the state of the lipids surrounding the channels, but a direct effect of ether and halothane on the protein part of the channels cannot be ruled out. Ether did not affect the capacitance of the axon membrane.
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Haydon DA, Requena J, Urban BW. Some effects of aliphatic hydrocarbons on the electrical capacity and ionic currents of the squid giant axon membrane. J Physiol 1980; 309:229-45. [PMID: 7252865 PMCID: PMC1274582 DOI: 10.1113/jphysiol.1980.sp013506] [Citation(s) in RCA: 59] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
1. The electrical properties of squid giant axons were examined by means of admittance bridges at frequencies from 0.5 to 300 kHz. A simple equivalent circuit was used to estimate the membrane capacity. 2. The calculated membrane capacities decreased monotonically over the whole frequency range. 3. At 100 kHz and higher frequencies the membrane capacity was independent of potential. 4. At frequencies greater than 20 kHz, exposure of the axons to saturated or 0.9 saturated solutions of n-pentane (275-306 micrometer) reduced the capacity per unit area by 0.1-0.15 micro F cm-2. 5. At 1 kHz the effect of the saturated pentane solutions depended on the membrane potential. In axons having potentials between -60 and zero mV the pentane solutions lowered the capacity, whereas for potentials between -160 and -60 mV they produced little or no change. 6. Saturated solutions of n-hexane, n-heptane and n-octane exhibited qualitatively similar, but quantitatively smaller influences on the membrane capacity, the changes declining as the chain length increased. 7. Under voltage clamp, the peak inward and steady-state outward currents were partially suppressed by the hydrocarbons. Saturated solutions of n-pentane usually reduced the former (reversibly) by 60-80% and the latter by 20-40%. Solutions of n-hexane, n-heptane and n-octane appeared to have successively less effect. Except in deteriorating axons, none of the hydrocarbons produced any consistent changes in the passive membrane resistance, the resting potential or in the reversal potential of the transient inward current. 8. Both the changes in the clamp currents and in the membrane capacity were largely, though not usually completely, reversible. In the hydrocarbon solution the axons deteriorated more rapidly than normal. 9. The responses of axons of Doryteuthis plei to the hydrocarbons were very similar to those of Loligo forbesi with the exception that for the former all observed changes were some five times faster. 10. The time courses of the peak inward and steady-state outward currents on exposure of the axons to n-pentane resembled the time course of the change in membrane capacity at 100 kHz. 11. The simplest interpretation of the high frequency capacity results is suggested to be that, as for lipid bilayers, the membranes become thicker through adsorption of the hydrocarbon.
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Speeg KV, Wang S, Avant GR, Berman ML, Schenker S. Antagonism of benzodiazepine binding in brain by Antilirium, benzyl alcohol, and physostigmine. J Neurochem 1980; 34:856-65. [PMID: 6102112 DOI: 10.1111/j.1471-4159.1980.tb09658.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
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Lindholm DB, Khawaja JA. Alterations in number and activity of cerebral free and membrane-bound ribosomes after prolonged ethanol ingestion by the weanling rat. Neuroscience 1979; 4:1007-13. [PMID: 552610 DOI: 10.1016/0306-4522(79)90183-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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Low PS, Lloyd DH, Stein TM, Rogers JA. Calcium displacement by local anesthetics. Dependence on pH and anesthetic charge. J Biol Chem 1979. [DOI: 10.1016/s0021-9258(18)50705-5] [Citation(s) in RCA: 68] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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Turner GL, Oldfield E. Effect of a local anaesthetic on hydrocarbon chain order in membranes. Nature 1979; 277:669-70. [PMID: 423968 DOI: 10.1038/277669a0] [Citation(s) in RCA: 68] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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Richards CD, Martin K, Gregory S, Keightley CA, Hesketh TR, Smith GA, Warren GB, Metcalfe JC. Degenerate perturbations of protein structure as the mechanism of anaesthetic action. Nature 1978; 276:775-9. [PMID: 723953 DOI: 10.1038/276775a0] [Citation(s) in RCA: 167] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
The interaction of the n-alkanols with lipid bilayers and excitable membranes shows that there is no simple correlation between conduction block and any of the perturbations of bilayer structure currently proposed as unitary mechanisms of local anaesthetic action. We propose instead that the n-alkanols act by direct interaction with target proteins to cause perturbations which depend directly on the precise structure of the alcohol.
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Hendry BM, Urban BW, Haydon DA. The blockage of the electrical conductance in a pore-containing membrane by the n-alkanes. BIOCHIMICA ET BIOPHYSICA ACTA 1978; 513:106-16. [PMID: 82449 DOI: 10.1016/0005-2736(78)90116-5] [Citation(s) in RCA: 51] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
1. In monooelein bilayers made highly conducting by the addition of a fixed amount of o-pyromellitylgramicidin, the membrane conductance has been shown to be strongly dependent on the chain length of the n-alkane with which the membrane is in equilibrium. Thus for n-hexadecane, the conductance is larger by approx. 10(4) times than it is for n-octane. This result is independent of whether the polypeptide is introduced via the aqueous or lipid phases. 2. The observed conductance variations have been accounted for in terms of a mechanism (outlined in earlier publications) which is based on the thickness and tension changes produced in bilayers by the adsorption of n-alkanes. Essentially quantitative agreement between theory and experiment is found.
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