Abstract
Although the physiological properties of myelinated nerve fibres, such as action potential duration, are known to vary with fibre size1,2, there has been little systematic examination of whether their biophysical properties show a similar variation (for example, in ionic conductance). Rather, differences have been identified between fibres on the basis of species3–6, or on whether the fibres are sensory or motor7,8. We report here the results of a comparison of amphibian (Rana pipiens) fibres of different sizes. Surprisingly, only the largest fibres (16–20 µm), usually selected for voltage-clamp study, had the large outward potassium currents described initially by Dodge and Franken-hauser9. Small fibres (9–11 µm) had little or no potassium conductance, and fibres of intermediate diameter had properties graded between these two extremes. This gradual loss of potassium conductance in fibres of decreasing size seemed to be due to the progressive electrical concealment of the potassium channels beneath the paranodal myelin. Thus brief treatment with the demyelinating agent lysophosphatidyl choline10,11 induced a large potassium conductance in the smaller fibres, but had little effect on the ionic currents of large fibres. We conclude that the biophysical properties of myelinated nerve fibres can vary with fibre size.
This is a preview of subscription content, access via your institution
Access options
Subscribe to this journal
Receive 51 print issues and online access
$199.00 per year
only $3.90 per issue
Buy this article
- Purchase on Springer Link
- Instant access to full article PDF
Prices may be subject to local taxes which are calculated during checkout
Similar content being viewed by others
References
Paintal, A. S. J. Physiol., Lond. 184, 791–811 (1966).
Jack, J. J. B. Br. J. Anaesth. 47, 173–182 (1975).
Horakova, M., Nonner, W. & Stämpfli, R. Proc. int. Un. int. Physiol. Sci. 7, 198 (1968).
Brismar, T. Acta physiol. scand. 105, 384–386 (1979).
Chiu, S. Y., Ritchie, J. M., Rogart, R. D. & Stagg, D. J. Physiol., Lond. 292, 149–166 (1979).
Ilyin, V., Katina, I. E., Lonskii, A. V., Makovsky, V. S. & Polishchuk, E. V. J. Membrane Biol. 57, 179–193 (1980).
Neumcke, B., Schwarz, W. & Stämpfli, R. Pflügers Arch. ges. Physiol. 387, 9–16 (1980).
Palti, Y., Moran, N. & Stämpfli, R. Biophys. J. 32, 955–966 (1980).
Dodge, F. A. & Frankenhauser, B. J. Physiol., Lond. 143, 76–90 (1958).
Chiu, S. Y. & Ritchie, J. M. Nature 284, 170–171 (1980).
Smith, K. J. & Schauf, C. L. Science 212, 1170–1171 (1981).
Hille, B. J. gen. Physiol. 58, 599–619 (1971).
Schmidt, H. & Stämpfli, R. Helv. physiol. pharmac. Acta 22, C143–C145 (1964).
Stämpfli, R. & Hille, B. Frog Neurobiology (eds Llinas, R. & Precht, W.) (Springer, Berlin, 1976).
Pencek, T. L., Schauf, C. L. & Davis, F. A. J. Pharmac. exp. Ther. 204, 400–405 (1978).
Smith, K. J. & Schauf, C. L. J. Pharmac. exp. Ther. 217, 719–726 (1981).
Hille, B. & Campbell, D. T. J. gen. Physiol. 67, 265–293 (1976).
Hille, B. Biophysics and Physiology of Excitable Membranes (ed. Adelman, W. J.) 230–246 (Van Nostrand, New York, 1971).
Sigworth, F. J. thesis, Yale Univ. (1979).
Bergman, C. Pflügers Arch. ges. Physiol. 317, 287–302 (1970).
Sherratt, R. M., Bostock, H. & Sears, T. A. Nature 283, 570–572 (1980).
Brismar, T. J. Physiol., Lond. 298, 171–184 (1980).
Smith, K. J. & Hall, S. M. J. neurol. Sci. 48, 201–219 (1980).
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Smith, K., Schauf, C. Size-dependent variation of nodal properties in myelinated nerve. Nature 293, 297–299 (1981). https://doi.org/10.1038/293297a0
Received:
Accepted:
Issue Date:
DOI: https://doi.org/10.1038/293297a0
This article is cited by
-
Differential sensitivity of amphibian nodal and paranodal K+ channels to 4-aminopyridine and TEA
Experientia (1987)
-
Internodal microvillus-like Schwann cell fingers in myelinated fibres in mouse spinal roots
Journal of Neurocytology (1985)
-
Presynaptic currents in frog motor endings
Pfl�gers Archiv European Journal of Physiology (1984)
-
Cable theory in neurons with active, linearized membranes
Biological Cybernetics (1984)
-
Electron microscopic serial section analysis of nodes of Ranvier in lumbosacral spinal roots of the cat: ultrastructural organization of nodal compartments in fibres of different sizes
Journal of Neurocytology (1983)
Comments
By submitting a comment you agree to abide by our Terms and Community Guidelines. If you find something abusive or that does not comply with our terms or guidelines please flag it as inappropriate.