Alternating current studies of charge carrier transport in lipid bilayers. Pentachlorophenol in lecithin-cholesterol membranes

Pickar, Arnold D.; Amos, William D.

doi:10.1016/0005-2736(76)90152-8

Cited by 16 publications

(5 citation statements)

References 12 publications

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“…The time constants T X and T 2 are identical with the relaxation times observed in the voltage-jump experiment [equation (62 A number of theoretical studies have dealt with alternating current behaviour of ion transport systems in planar bilayers (Ketterer et al 1971;Aityan, Markin & Chizmadzhev, 1973;Rangarajan, Seelig & DeLevie, 1979;DeLevie & Seelig, 1981). Alternating-current techniques have been applied to membranes containing hydrophobic ions (DeLevie et al 1974;DeLevie & Vukadin, 1975;DeLevie, Thomas & Abbey, 1975) or weak-acid uncouplers and ion carriers (Lebedev & L. J. Boguslavskii, 1971;Pickar & Amos, 1976). A more detailed analysis of experimental a.c. data on the basis of microscopic transport models would be desirable.…”

Section: Am (Homentioning

confidence: 94%

“…The quantities P, Q and J are defined by equations (63H65). Alternating-current techniques have been applied to membranes containing hydrophobic ions (DeLevie et al 1974;DeLevie & Vukadin, 1975;DeLevie, Thomas & Abbey, 1975) or weak-acid uncouplers and ion carriers (Lebedev & L. J. Boguslavskii, 1971;Pickar & Amos, 1976). Alternating-current techniques have been applied to membranes containing hydrophobic ions (DeLevie et al 1974;DeLevie & Vukadin, 1975;DeLevie, Thomas & Abbey, 1975) or weak-acid uncouplers and ion carriers (Lebedev & L. J. Boguslavskii, 1971;Pickar & Amos, 1976).…”

Section: Am (Homentioning

confidence: 99%

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Relaxation studies of ion transport systems in lipid bilayer membranes

Läuger

Benz

Stark

et al. 1981

Quart. Rev. Biophys.

165

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Relaxation techniques have been widely used in kinetic studies of chemical reactions in homogeneous solution (Eigen & DeMayer, 1963). The principle of this method is well known: an external variable such as temperature or pressure is suddenly changed and the time course of a state parameter of the system such as concentration is recorded as it approaches a new steady value. Relaxation techniques can also be used for studying the rate of elementary processes in membranes. This method has proved particularly useful for the investigation of ion transport systems (ion carriers, channels, pumps) in artificial planar bilayer membranes. In this review we describe different relaxation techniques which have been developed for this purpose during the last years, as well as applications to a number of ion transport systems.

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Section: Am (Homentioning

confidence: 94%

Section: Am (Homentioning

confidence: 99%

Relaxation studies of ion transport systems in lipid bilayer membranes

Läuger

Benz

Stark

et al. 1981

Quart. Rev. Biophys.

165

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“…An alternative method to study such transport process is the measurement of the impedance or admittance of transport systems in a membrane when an alternating voltage is applied. These methods provide results analogous to the current relaxation or charge relaxation methods (Markin and Chizmadzhev 1974;Pickar and Amos 1976;Hladky 1979;Rangarajan et al 1979;Wang et al 1994). The simplest version of the admittance method is the measurement of the "pseudo capacitance," an increase of the apparent membrane capacitance caused by ion transport.…”

Section: Introductionmentioning

confidence: 99%

Influence of sodium concentration on changes of membrane capacitance associated with the electrogenic ion transport by the Na,K-ATPase

Sokolov

Stukolov

Darmostuk

et al. 1998

European Biophysics Journal

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Electrogenic ion transport by the Na,K-ATPase was investigated in a model system of protein-containing membrane fragments adsorbed to a lipid bilayer. Transient Na + currents were induced by photorelease of ATP from inactive caged ATP. This process was accompanied by a capacitance change of the membrane system. Two methods were applied to measure capacitances in the frequency range 1 to 6000 Hz. The frequency dependent capacitance increment, ∆C, was of sigmoidal shape and decreased at high frequencies. The midpoint frequency, f 0 , depended on the ionic strength of the buffer. At 150 mM NaCl f 0 was about 200 Hz and decreased to 12 Hz at high ionic strength (1 M). At low frequencies (f K f 0 ) the capacitance increment became frequency independent. It was, however, dependent on Na + concentration and on the membrane potential which was generated by the charge transferred. A simple model is presented to analyze the experimental data quantitatively as a function of two parameters, the capacitance of the adsorbed membrane fragments, C P , and the potential of maximum capacitance increment, ψ 0 . Below 5 mM Na + a negative capacitance change was detected which may be assigned to electrogenic Na + binding to cytoplasmic sites. It could be shown that the results obtained by experiments with the presented alternating current method contain the information which is determined by current-relaxation experiments with cell membranes.

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“…Both are known to be uncouplers of oxidative phosphorylation [32][33][34]36]. PCP is a commonly used pesticide that has been extensively studied [13,21,22,25,26,[32][33][34]. We have found, for example, that the onset of toxic effect due to PCP measured by the rate of carbon assimilation by an alga, occurs in parallel with the decrease of membrane electrical resistance [9].…”

Section: Introductionmentioning

confidence: 99%

Electrical conductivity, transfer of hydrogen ions in lipid bilayer membranes and uncoupling effect induced by pentachlorobenzenethiol (Pentachlorothiophenol)

1983

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Pentachlorobenzenethiol (PCBT) has been considered an anomalous uncoupler. It was reported as active in mitochondria, but not effective in inducing electrical conductivity in lipid bilayer membranes. We have overcome the experimental difficulties associated with accurate determination of the induced conductivity. The main contributing factors to the difficulties, we discovered, are the photolability and the low solubility of the compound in aqueous medium. We have conclusively demonstrated that PCBT does induce conductivity in lipid bilayers and compared this conductance with its uncoupling activity reported by other investigators in the literature. We present the results of steady-state current-voltage measurements: conductance dependence on applied voltage for various values of pH, buffer strength and PCBT concentration, as well as the dependence of the conductance on pH, buffer strength and PCBT concentration in the limit of zero applied voltage. We have also compared the above results with those obtained previously with pentachlorophenol. Our experimental results on PCBT-induced membrane conductance suggest that PCBT belongs to class II uncouplers and that "disulfide dimer" of PCBT is membrane inactive. Thus the replacement of oxygen in molecular structure of pentachlorophenol (R-OH) by sulfur (R-SH) does not change the protonophoretic activity of the compound. The conductivity of a membrane is due to PCBT-induced hydrogen ion transfer and it was found to be limited by the kinetics of reactions coupled to transmembrane charge transfer.(ABSTRACT TRUNCATED AT 250 WORDS)

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Alternating current studies of charge carrier transport in lipid bilayers. Pentachlorophenol in lecithin-cholesterol membranes

Cited by 16 publications

References 12 publications

Relaxation studies of ion transport systems in lipid bilayer membranes

Relaxation studies of ion transport systems in lipid bilayer membranes

Influence of sodium concentration on changes of membrane capacitance associated with the electrogenic ion transport by the Na,K-ATPase

Electrical conductivity, transfer of hydrogen ions in lipid bilayer membranes and uncoupling effect induced by pentachlorobenzenethiol (Pentachlorothiophenol)

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