CoChat
Sign Up
Cited by 329Ion channel regulation and functionMultiple Sclerosis Research StudiesPeripheral Neuropathies and Disorders

Internodal conduction in undissected demyelinated nerve fibres

Open access
Rasminsky, M., Sears, T. A.·1972·The Journal of Physiology
DOI 10.1113/jphysiol.1972.sp010035PMC PMC1331198
Open this paper in CoChat — free account

Abstract

1. A new method is described for recording external longitudinal currents from single undissected nerve fibres in rat ventral roots. The method permits identification of the sites of fifteen or more successive nodes of Ranvier in a given single fibre and the measurement of internodal conduction times between them. 2. Average internodal conduction time for normal ventral root fibres of internodal length between 0·75 and 1·45 mm is 19·7 ± 4·6 ( S.D.) μsec at 37° C. Internodal conduction time appeared to show a minimum for fibres of internodal length 1·0 mm. 3. Ventral roots were demyelinated by focal application of diphtheria toxin. Although conduction is markedly slowed in demyelinated fibres, sites of inward membrane current remain spatially separated indicating that conduction remains saltatory to the point of conduction block rather than becoming continuous as in unmyelinated fibres. 4. Slowing of conduction appears to be due to changes in the passive electrical properties of the internodal myelin. Evidence is presented suggesting that there is an increase in internodal capacitance and a decrease in internodal transverse resistance at internodes of demyelinated fibres; such changes would have the effect of delaying excitation at the nodes. The changes in passive electrical properties, which appear to be primarily in the vicinity of the nodes, would be consistent with the pathological changes observed in demyelinated fibres. 5. Internodal conduction times in demyelinated fibres have ranged from normal (26 μsec at 30° C) to more than 600 μsec. There is a great variation in internodal conduction time at successive internodes of a given single fibre; this presumably reflects the varying severity of demyelination of successive internodes. 6. As in normal fibres, nodes of demyelinated fibres generate less current when excited by the second of two closely spaced impulses. This results in an increased internodal conduction time for the second impulse and, at a critically short interstimulus interval, conduction block of the second impulse. 7. The increased refractory period of transmission of internodes with increased internodal conduction times is a consequence of the decreased ability of such internodes to sustain propagation in the face of small decreases in nodal current. 8. During tetanic stimulation, increases in internodal conduction time are associated with corresponding decreases in nodal current generated by the node proximal to the internode in question. 9. It is suggested that changes in the magnitude of the nodal current during repetitive activity are due to changes in transmembrane concentration gradients of sodium, the increased internodal conduction time and eventual conduction block during tetanic stimulation being caused by intracellular sodium accumulation. 10. Intracellular sodium accumulation is also offered as the explanation for the post‐tetanic depression seen in demyelinated fibres.

Integrity signals

Registry

Crossref · 10.1113/jphysiol.1972.sp010035

Cites

36 of 36 references verified0 citation errors · 0 not checkable

Statistics

Recomputing p-values needs the paper’s full text.

Claims the paper makes

The text we found for this paper looks like another document, so its claims and self-check weren’t run. The registry and citation checks still apply.

Self-check

Percentages, sums and reported differences re-computed from the paper’s own numbers.

The text we found for this paper looks like another document, so the self-check wasn’t run.

Cites

Flagged first, then by citations

Research works printed but not linked: 2

  1. Lehmann H. J., Lehmann G., Tackmann W. Refraktärperiode und Ubermittlung von Serienimpulsen im N. tibialis des Meerschweinchens bei experimenteller allergischer Neuritis. Z Neurol. 1971 Apr 28;199(1):67–85. [PubMed] [Google Scholar]
  2. Lehmann H. J., Pretschner D. P. Experimentelle Untersuchungen zum Engpasssyndrom peripherer Nerven. Dtsch Z Nervenheilkd. 1966 May 6;188(4):308–330. [PubMed] [Google Scholar]

Cited by

Sorted by citations

Related

Authors
Rasminsky, M., & Sears, T. A.
ORCID
Sears, T. A.
Venue
The Journal of Physiology
Publisher
Wiley
Published
1972-12
Volume
227
Issue
2
Pages
323-350
ISSN
  • 0022-3751 (ISSN-L)
  • 1469-7793
DOI
10.1113/jphysiol.1972.sp010035
PMC
PMC1331198
OpenAlex
W2013611803
Cited by
329
References
36
Citations by year
2026: 4 · 2025: 1 · 2024: 3 · 2023: 3 · 2022: 4 · 2021: 4 · 2020: 5 · 2019: 5 · 2018: 2 · 2017: 2 · 2016: 2 · 2015: 2 · 2014: 3 · 2013: 4 · 2012: 5
FWCI
3.33
Type
journal article
Language
en
Open access
Licence
onlinelibrary.wiley.com/termsAndConditions#vor (vor)
Locations
  • The Journal of Physiology (publishedVersion)
  • PubMed Central (publishedVersion)
  • PubMed (publishedVersion)
Topics
  • Life Sciences › Biochemistry, Genetics and Molecular Biology › Molecular Biology › Ion channel regulation and function
  • Health Sciences › Medicine › Pathology and Forensic Medicine › Multiple Sclerosis Research Studies
  • Health Sciences › Medicine › Neurology › Peripheral Neuropathies and Disorders
Keywords
demyelination, nodes of Ranvier, saltatory conduction, conduction block, refractory period, tetanic stimulation, demyelinating disease
MeSH terms
Action Potentials, Animals, Axons, Biological Transport, Active, Demyelinating Diseases, Diphtheria Toxin, Electric Stimulation, Membrane Potentials, Myelin Sheath, Neural Conduction, Ranvier's Nodes, Sodium, Spinal Nerve Roots, Rats

About these checks

Registry, retraction, Cites and statistics results are computed, not judged, with one exception: a printed reference that no index lists is read once by a model before it counts as a citation error. Claims are extracted by a model and kept only when their quote appears verbatim in the text; each cited source is then checked, with a model’s help, for whether it says what the claim relies on. Those verdicts can be wrong — read the claim’s quote and the cited source before relying on one.

Statistics and arithmetic are recomputed, not judged.

Confidence bands are shown only for fields calibrated on our annotated test set. None is calibrated yet, so no band is shown.

What counts as a claim ›How we measure confidence ›How we check this ›

Are you an author, or do you see a problem with this page? Request a review