Cargando…
Ionic Permeability of Thin Lipid Membranes : Effects of n-alkyl alcohols, polyvalent cations, and a secondary amine
Ultrathin (black) lipid membranes were made from sheep red cell lipids dissolved in n-decane. The presence of aliphatic alcohols in the aqueous solutions bathing these membranes produced reversible changes in the ionic permeability, but not the osomotic permeability. Heptanol (8 mM), for example, ca...
Autores principales: | , |
---|---|
Formato: | Texto |
Lenguaje: | English |
Publicado: |
The Rockefeller University Press
1970
|
Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2203006/ https://www.ncbi.nlm.nih.gov/pubmed/5535355 |
_version_ | 1782148351836291072 |
---|---|
author | Gutknecht, John Tosteson, D. C. |
author_facet | Gutknecht, John Tosteson, D. C. |
author_sort | Gutknecht, John |
collection | PubMed |
description | Ultrathin (black) lipid membranes were made from sheep red cell lipids dissolved in n-decane. The presence of aliphatic alcohols in the aqueous solutions bathing these membranes produced reversible changes in the ionic permeability, but not the osomotic permeability. Heptanol (8 mM), for example, caused the membrane resistance (R(m)) to decrease from >10(8) to about 10(5) ohm-cm(2) and caused a marked increase in the permeability to cations, especially potassium. In terms of ionic transference numbers, deduced from measurements of the membrane potential at zero current, T (cat)/T (Cl) increased from about 6 to 21 and T (K)/T (Na) increased from about 3 to 21. The addition of long-chain (C(8)ndash;C(10)) alcohols to the lipid solutions from which membranes were made produced similar effects on the ionic permeability. A plot of log R(m) vs. log alcohol concentration was linear over the range of maximum change in R(m), and the slope was -3 to -5 for C(2) through C(7) alcohols, suggesting that a complex of several alcohol molecules is responsible for the increase in ionic permeability. Membrane permselectivity changed from cationic to anionic when thorium or ferric iron (10(-4) M) was present in the aqueous phase or when a secondary amine (Amberlite LA-2) was added to the lipid solutions from which membranes were made. When membranes containing the secondary amine were exposed to heptanol, R(m) became very low (10(3)–10(4) ohm-cm(2)) and the membranes became perfectly anion-selective, developing chloride diffusion potentials up to 150 mv. |
format | Text |
id | pubmed-2203006 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 1970 |
publisher | The Rockefeller University Press |
record_format | MEDLINE/PubMed |
spelling | pubmed-22030062008-04-23 Ionic Permeability of Thin Lipid Membranes : Effects of n-alkyl alcohols, polyvalent cations, and a secondary amine Gutknecht, John Tosteson, D. C. J Gen Physiol Article Ultrathin (black) lipid membranes were made from sheep red cell lipids dissolved in n-decane. The presence of aliphatic alcohols in the aqueous solutions bathing these membranes produced reversible changes in the ionic permeability, but not the osomotic permeability. Heptanol (8 mM), for example, caused the membrane resistance (R(m)) to decrease from >10(8) to about 10(5) ohm-cm(2) and caused a marked increase in the permeability to cations, especially potassium. In terms of ionic transference numbers, deduced from measurements of the membrane potential at zero current, T (cat)/T (Cl) increased from about 6 to 21 and T (K)/T (Na) increased from about 3 to 21. The addition of long-chain (C(8)ndash;C(10)) alcohols to the lipid solutions from which membranes were made produced similar effects on the ionic permeability. A plot of log R(m) vs. log alcohol concentration was linear over the range of maximum change in R(m), and the slope was -3 to -5 for C(2) through C(7) alcohols, suggesting that a complex of several alcohol molecules is responsible for the increase in ionic permeability. Membrane permselectivity changed from cationic to anionic when thorium or ferric iron (10(-4) M) was present in the aqueous phase or when a secondary amine (Amberlite LA-2) was added to the lipid solutions from which membranes were made. When membranes containing the secondary amine were exposed to heptanol, R(m) became very low (10(3)–10(4) ohm-cm(2)) and the membranes became perfectly anion-selective, developing chloride diffusion potentials up to 150 mv. The Rockefeller University Press 1970-03-01 /pmc/articles/PMC2203006/ /pubmed/5535355 Text en Copyright © 1970 by The Rockefeller University Press This article is distributed under the terms of an Attribution–Noncommercial–Share Alike–No Mirror Sites license for the first six months after the publication date (see http://www.rupress.org/terms). After six months it is available under a Creative Commons License (Attribution–Noncommercial–Share Alike 4.0 Unported license, as described at http://creativecommons.org/licenses/by-nc-sa/4.0/). |
spellingShingle | Article Gutknecht, John Tosteson, D. C. Ionic Permeability of Thin Lipid Membranes : Effects of n-alkyl alcohols, polyvalent cations, and a secondary amine |
title | Ionic Permeability of Thin Lipid Membranes : Effects of n-alkyl alcohols, polyvalent cations, and a secondary amine |
title_full | Ionic Permeability of Thin Lipid Membranes : Effects of n-alkyl alcohols, polyvalent cations, and a secondary amine |
title_fullStr | Ionic Permeability of Thin Lipid Membranes : Effects of n-alkyl alcohols, polyvalent cations, and a secondary amine |
title_full_unstemmed | Ionic Permeability of Thin Lipid Membranes : Effects of n-alkyl alcohols, polyvalent cations, and a secondary amine |
title_short | Ionic Permeability of Thin Lipid Membranes : Effects of n-alkyl alcohols, polyvalent cations, and a secondary amine |
title_sort | ionic permeability of thin lipid membranes : effects of n-alkyl alcohols, polyvalent cations, and a secondary amine |
topic | Article |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2203006/ https://www.ncbi.nlm.nih.gov/pubmed/5535355 |
work_keys_str_mv | AT gutknechtjohn ionicpermeabilityofthinlipidmembraneseffectsofnalkylalcoholspolyvalentcationsandasecondaryamine AT tostesondc ionicpermeabilityofthinlipidmembraneseffectsofnalkylalcoholspolyvalentcationsandasecondaryamine |