Chain-length dependence of n-alkane solubility in phosphatidylcholine bilayers: a 2H-NMR study

Pope, J. H.; Littlemore, Linda; Westerman, P. W.

doi:10.1016/0005-2736(89)90201-0

Cited by 20 publications

(8 citation statements)

References 22 publications

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“…The cut-off will occur when an agent is approached for which the Meyer-Overton solubility threshold at the site cannot be attained due to a low solubility of the agent. This discussion challenges the suggestions, made in the literature, that cut-off effects occur by 'sudden change' or 'sudden disappearance' of some crucial property Westerman et al, 1988;Pope et al, 1989;Westerman and Pope, 1991). We see that an abrupt appearance of the cut-off does not imply a steep perturbation function.…”

Section: Molecular Perturbations Vs Concentration Effects In the Fircontrasting

confidence: 51%

“…This line of reasoning shows the weakness of suggestions made in the literature that the cut-off effect occurs by 'sudden change' or 'sudden disappearance' of some crucial property Westerman et al, 1988;Pope et al, 1989;Westerman and Pope, 1991). We can also try to deduce the factor responsible for the perfluorocarbons cut-off by the use of solution theory arguments.…”

Section: Appendixmentioning

confidence: 97%

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Four Applications of the Anesthetic Cut-off Effect

Katz

2000

Bulletin of Mathematical Biology

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This article presents and analyses several cases in which the use of the cut-off effect is useful. It starts from the fact that an anesthetic effect of homologous agents is always expressible as a function of their chain lengths and that the cut-off point is a point at which the function vanishes. We then investigate four categories of results: (i) whole body effects. (ii) Cases in which the anesthetics affect the Hodgkin-Huxley parameters of a nerve. (iii) Molecular mechanisms of anesthetic action. (iv) The physical chemistry of the anesthetic process. Our discussion shows that it is possible to incorporate these apparently remote results into one framework. It also shows how to compare results that were gathered by independent measuring methods. In some instances we suggest an interpretation, in others we suggest a further gathering of experimental data. One of the deductions indicates that a weakness exists in the lipid theories of anesthesia.

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Section: Molecular Perturbations Vs Concentration Effects In the Fircontrasting

confidence: 51%

Section: Appendixmentioning

confidence: 97%

Four Applications of the Anesthetic Cut-off Effect

Katz

2000

Bulletin of Mathematical Biology

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“…Both solutes alter the PS inter-headgroup spacing, and hence the surface charge density and surface hydrophobicity of the LUV, which could affect the contact rate (Ohki and Arnold, 1990). However, the effect of 18: 1,18:1 DAG on the surface potential is greater than the effect of HD (McIntosh et al, 1980;Pope et al, 1989;Cunningham et al, 1989), as expected, since the 18:1,18:1 DAG headgroup resides at the lipid-water interface even when equilibrated with Ca2" (Hamilton et al, 1991), whereas HD resides primarily in the bilayer. These differences in solute distribution make it unlikely that the lipid mixing effects observed here are due to changes in the headgroup region.…”

Section: Discussionmentioning

confidence: 99%

Diacylglycerol and hexadecane increase divalent cation-induced lipid mixing rates between phosphatidylserine large unilamellar vesicles

Walter

Yèagle

Siegel

1994

Biophysical Journal

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Bovine brain phosphatidylserine (BBPS) vesicles were prepared with traces of dioleoylglycerol (18:1, 18:1 DAG) or hexadecane (HD) to determine the influence of changes in headgroup or acyl chain packing on divalent cation-induced lipid mixing rates. A stopped-flow apparatus was used to combine vesicles with 3 mM Ca2+ or Ba2+. Aggregation was monitored by light scattering and lipid mixing by lipid probe dilution. Neither 3-6 mol% 18:1, 18:1 DAG nor up to 10 mol % HD significantly altered the BBPS chain melting temperature, vesicle diameter, or vesicle aggregation rates. Lipid mixing rates doubled by adding either 3 mol % 18:1, 18:1 DAG or 6 mol % HD to BBPS with no change in the Ca2+ concentration threshold. The Arrhenius slopes of the lipid mixing rates for control, 3 mol % 18:1, 18:1 DAG, and 6 mol % HD vesicles were identical. 2H-nuclear magnetic resonance spectra of perdeuterated dipalmitoylglycerol and HD in BBPS in the absence and presence of Ca2+ and Ba2+ showed that the solutes occupied different time-averaged positions in the bilayer under each condition. These data suggest that: 1) the enhanced lipid mixing rate is related to the volume of the added alkyl chains; 2) 18:1, 18:1 DAG and HD may alter the activation entropy or the attempt frequency at one or more steps in the lipid mixing process; 3) 18:1, 18:1 DAG and HD are likely to act at a different spatial or temporal point than the divalent cation; and 4) it is unlikely that the effect of these solutes on lipid mixing is due to their equilibrium time-averaged positions in the bilayer. Others have shown that apolar lipids accelerate fusion in nonbilayer phase-forming systems, but BBPS does not form these phases under these conditions. Therefore, we propose that the effect of very small amounts of apolar substances may be very general, e.g., stabilizing the hydrophobic interstices associated with a variety of proposed intermediate structures.

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“…n-Hexane, is a hydrophobic aliphatic molecule that is supposed to partition readily into the inner region of phospholipid membranes (McIntosh et al, 1980;White et al, 1981;Pope et al, 1989;MacCallum and Tieleman, 2006).…”

Section: Effects Of Membrane Partitioning Of Nonpolar Hydrocarbon Solventsmentioning

confidence: 99%

Organic solvent-induced changes in membrane geometry in human SH-SY5Y neuroblastoma cells – a common narcotic effect?

et al. 2016

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Chain-length dependence of n-alkane solubility in phosphatidylcholine bilayers: a 2H-NMR study

Cited by 20 publications

References 22 publications

Four Applications of the Anesthetic Cut-off Effect

Four Applications of the Anesthetic Cut-off Effect

Diacylglycerol and hexadecane increase divalent cation-induced lipid mixing rates between phosphatidylserine large unilamellar vesicles

Organic solvent-induced changes in membrane geometry in human SH-SY5Y neuroblastoma cells – a common narcotic effect?

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