Structure of the axolemma of frog myelinated nerve: Relaxation experiments with a lipophilic probe ion

Roland Benz, Wolfgang Nonner

Research output: Contribution to journalArticle

21 Citations (Scopus)

Abstract

Asymmetrical displacement currents are measured in the absence and in the presence of the lipophilic anion dipicrylamine (DPA) in the extracellular solution of nerve fibres of the frog Rana esculenta. DPA (30 nM-3 μM) enhances the current by a component that has the properties expected for a translocation current of DPA ion across the lipid membrane. Analysis in terms of a single-barrier model yields the translocation rate constant (k), the total surface density of DPA absorbed to the membrane (Nt), and the equidistribution voltage (Ψ). The value of k of about 104 s-1 is similar to that for a solvent-free artificial bilayer formed by the Montal-Mueller method. The surface density Nt varies with the DPA concentration as it does in the artificial bilayer, but is about tenfold smaller at all concentrations. The DPA ions sense an intrinsic electric field that is offset by a transmembrane voltage between 0 and 30 mV (inside positive). The part of the axolemma probed by the DPA ion appears as a thin (<2.5 nm), fluid bilayer of lipids. DPA ions seem, however, to be excluded from the major part of the axolemma as if this area is occupied by integral proteins or negative charges.

Original languageEnglish
Pages (from-to)127-134
Number of pages8
JournalThe Journal of Membrane Biology
Volume59
Issue number2
DOIs
StatePublished - Jun 1 1981
Externally publishedYes

Fingerprint

Anura
Ions
Rana esculenta
dipicrylamine
Lipid Bilayers
Membrane Lipids
Nerve Fibers
Anions
Membranes
Proteins

ASJC Scopus subject areas

  • Physiology
  • Cell Biology
  • Biophysics

Cite this

Structure of the axolemma of frog myelinated nerve : Relaxation experiments with a lipophilic probe ion. / Benz, Roland; Nonner, Wolfgang.

In: The Journal of Membrane Biology, Vol. 59, No. 2, 01.06.1981, p. 127-134.

Research output: Contribution to journalArticle

@article{e9e32bb674ec44a9aa8d2425f468fbb3,
title = "Structure of the axolemma of frog myelinated nerve: Relaxation experiments with a lipophilic probe ion",
abstract = "Asymmetrical displacement currents are measured in the absence and in the presence of the lipophilic anion dipicrylamine (DPA) in the extracellular solution of nerve fibres of the frog Rana esculenta. DPA (30 nM-3 μM) enhances the current by a component that has the properties expected for a translocation current of DPA ion across the lipid membrane. Analysis in terms of a single-barrier model yields the translocation rate constant (k), the total surface density of DPA absorbed to the membrane (Nt), and the equidistribution voltage (Ψ). The value of k of about 104 s-1 is similar to that for a solvent-free artificial bilayer formed by the Montal-Mueller method. The surface density Nt varies with the DPA concentration as it does in the artificial bilayer, but is about tenfold smaller at all concentrations. The DPA ions sense an intrinsic electric field that is offset by a transmembrane voltage between 0 and 30 mV (inside positive). The part of the axolemma probed by the DPA ion appears as a thin (<2.5 nm), fluid bilayer of lipids. DPA ions seem, however, to be excluded from the major part of the axolemma as if this area is occupied by integral proteins or negative charges.",
author = "Roland Benz and Wolfgang Nonner",
year = "1981",
month = "6",
day = "1",
doi = "10.1007/BF01875710",
language = "English",
volume = "59",
pages = "127--134",
journal = "Journal of Membrane Biology",
issn = "0022-2631",
publisher = "Springer New York",
number = "2",

}

TY - JOUR

T1 - Structure of the axolemma of frog myelinated nerve

T2 - Relaxation experiments with a lipophilic probe ion

AU - Benz, Roland

AU - Nonner, Wolfgang

PY - 1981/6/1

Y1 - 1981/6/1

N2 - Asymmetrical displacement currents are measured in the absence and in the presence of the lipophilic anion dipicrylamine (DPA) in the extracellular solution of nerve fibres of the frog Rana esculenta. DPA (30 nM-3 μM) enhances the current by a component that has the properties expected for a translocation current of DPA ion across the lipid membrane. Analysis in terms of a single-barrier model yields the translocation rate constant (k), the total surface density of DPA absorbed to the membrane (Nt), and the equidistribution voltage (Ψ). The value of k of about 104 s-1 is similar to that for a solvent-free artificial bilayer formed by the Montal-Mueller method. The surface density Nt varies with the DPA concentration as it does in the artificial bilayer, but is about tenfold smaller at all concentrations. The DPA ions sense an intrinsic electric field that is offset by a transmembrane voltage between 0 and 30 mV (inside positive). The part of the axolemma probed by the DPA ion appears as a thin (<2.5 nm), fluid bilayer of lipids. DPA ions seem, however, to be excluded from the major part of the axolemma as if this area is occupied by integral proteins or negative charges.

AB - Asymmetrical displacement currents are measured in the absence and in the presence of the lipophilic anion dipicrylamine (DPA) in the extracellular solution of nerve fibres of the frog Rana esculenta. DPA (30 nM-3 μM) enhances the current by a component that has the properties expected for a translocation current of DPA ion across the lipid membrane. Analysis in terms of a single-barrier model yields the translocation rate constant (k), the total surface density of DPA absorbed to the membrane (Nt), and the equidistribution voltage (Ψ). The value of k of about 104 s-1 is similar to that for a solvent-free artificial bilayer formed by the Montal-Mueller method. The surface density Nt varies with the DPA concentration as it does in the artificial bilayer, but is about tenfold smaller at all concentrations. The DPA ions sense an intrinsic electric field that is offset by a transmembrane voltage between 0 and 30 mV (inside positive). The part of the axolemma probed by the DPA ion appears as a thin (<2.5 nm), fluid bilayer of lipids. DPA ions seem, however, to be excluded from the major part of the axolemma as if this area is occupied by integral proteins or negative charges.

UR - http://www.scopus.com/inward/record.url?scp=0019795301&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0019795301&partnerID=8YFLogxK

U2 - 10.1007/BF01875710

DO - 10.1007/BF01875710

M3 - Article

C2 - 6264083

AN - SCOPUS:0019795301

VL - 59

SP - 127

EP - 134

JO - Journal of Membrane Biology

JF - Journal of Membrane Biology

SN - 0022-2631

IS - 2

ER -