Summary
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1.
Electron microscope studies on the olfactory nerve of the pike revealed a population of 4.2 million, densely packed unmyelinated nerve fibres; 95% are small fibres (average diameter 0.19 μm, narrow modal class), 5% are larger (average diameter 0.6 μm). Each fibre is bounded by an axonal membrane with a bilayer structure (80Å thickness).
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The olfactory nerve is birefringent (negative with respect to fibre axis) and shows at 20° C an average retardationR=23 nm. The birefringence becomes more negative on lowering the temperature.
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With the passage of an action potential a rapid, transient increase of retardation — the optical spike — occurs; ΔR=0.04 nm. The optical spike corresponds to the time course of structural changes in the axon membrane during excitation; it begins later, peaks earlier and decays more quickly than the voltage changes as recorded externally in the present study.
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References
Baylor, S. M., Oetliker, H.: Birefringence experiments on isolated skeletal muscle fibres suggest a possible signal from the sarcoplasmic reticulum. Nature (Lond.)253, 97–101 (1975)
Berestovsky, G. N., Liberman, E. A., Lunevsky, V. Z., Frank, G. M.: Optical study of the change in the structure of nerve membrane during impulse. (In Russian.) Biofizika15, 62–68 (1970)
Bezanilla, F., Horowicz, P.: Fluorescence intensity changes associated with contractile activation in frog muscle, stained with Nile Blue A. J. Physiol. (Lond.)246, 709–735 (1975)
Cohen, L. B., Keynes, R. D.: Evidence for structural changes during the action potential in nerves from the walking legs of Maia squinado. J. Physiol. (Lond.)194, 85–86 P (1968)
Cohen, L. B., Keynes, R. D., Hille, B.: Light scattering and birefringence changes during nerve activity. Nature (Lond.)218, 438–441 (1968)
Cohen, L. B., Hille, B., Keynes, R. D.: Light scattering changes during activity in the electric organ ofElectrophorus electricus. J. Physiol. (Lond.)203, 489–509 (1969)
Cohen, L. B., Hille, B., Keynes, R. D.: Changes in axon birefringence during the action potential. J. Physiol. (Lond.)211, 495–515 (1970)
Cohen, L. B., Keynes, R. D., von Muralt, A., Rojas, E.: Nouvelle méthode de mesure en ultraviolet de très petits changements de biréfringence et du dichroisme circulaire. J. Physiol. (Paris)62, 143–144 (1970)
Cohen, L. B., Hille, B., Keynes, R. D., Landowne, D., Rojas, E.: Analysis of the potential-dependent changes in optical retardation in the squid giant axon. J. Physiol. (Lond.)218, 205–237 (1971)
Cohen, L. B., Salzberg, H. V., Davila, H. V., Ross, W. N., Landowne, D., Waggoner, A. S., Wang, C. H.: Changes in axon fluorescence during activity: molecular probes of membrane potential. J. Membrane Biol.19, 1–36 (1974)
Easton, D. M.: Garfish olfactory nerve: easily accessible source of numerous homogenous non-myelinated axons. Science172, 952–955 (1971)
Entine, G.: Physical probes of nerve membrane structure. Thesis, Berkeley: University of California 1969
Fresnel, A.: 1821 quoted after Burri, C. Das Polarisationsmikroskop, p. 120. Basel: Birkhäuser 1950
Garten, S.: Physiologie der marklosen Nerven. Jena 1903.
Gasser, H. S.: Olfactory nerve fibers. J. gen. Physiol.39, 473–496 (1956)
Howarth, J. V., Keynes, R. D., Ritchie, J. M., von Muralt, A.: The heat production associated with the passage of a single impulse in pike olfactory nerve fibres. J. Physiol. (Lond.)249, 349–368 (1975)
Huggel, H., Kleinhaus, M., Hamzehpour, S.: Composition du sang de Salmo gairdneri irideus et Squalius cephalus. Rev. Suisse Zool.70, 286–290 (1963)
Illanes, A., von Muralt, A.: Fluorescence probe signals from excited heart muscle. Experientia (Basel)31, 710–711 (1975)
Keynes, R. D.: Evidence for structural changes during nerve activity and their relation to the conduction mechanism. In: The neurosciences: Second study program (F. O. Schmitt, ed.), pp. 707–714. New York: The Rockefeller University Press 1970
Keynes, R. D.: Excitable membranes. Nature (Lond.)239, 29–32 (1972)
Lüthy, H.: Absorptionsspektrometrie markloser und markhaltiger Nervenfasern im natürlichen und polarisierten ultravioletten Licht. Pflügers Arch.253, 477–502 (1951)
Lüthy, H., von Muralt, A.: Über den Ultraviolett-Dichroismus der peripheren Nervenfaser. Schweiz. med. Wschr.77, 10–14 (1947)
von Muralt, A.: Optical spike' during excitation in peripheral nerve. Abstracts of 25th Int. Physiol. Congress Munich, p. 638 (1971)
von Muralt, A.: The optical spike. In: Actualités Neurophysiologiques, vol. 10. Trends in neurophysiology (A. M. Monnier, ed.), pp. 3–8. Paris: Masson 1974
von Muralt, A.: The optical spike. Phil. Trans. B270, 411–423 (1975)
Oetliker, H., Baylor, S. M., Chandler, W. K.: Simultaneous changes in fluorescence and optical retardation in single muscle fibres during activity. Nature (Lond.)257, 693–696 (1975)
Ritchie, J. M., Straub, R. W.: The movement of potassium ions during electrical activity, and the kinetics of the recovery process, in the non-myelinated fibres of the Garfish olfactory nerve. J. Physiol. (Lond.)249, 327–348 (1975)
Salama, G., Morad, M.: Merocyanine 540 as an optical probe of transmembrane electrical activity in the heart. Science191, 485–487 (1976)
Schmidt, W. J.: Die Bausteine des Tierkörpers in polarisiertem Lichte. Bonn: F. Cohen 1924
Schrödinger, E.: What is Life? The physical aspect of the living cell. Cambridge: Univ. Press. 1944
Sowton, S. C. M.: Observations on the electromotive phenomena of nonmedullated nerve. Proc. roy. Soc.56, 379–389 (1900)
Tasaki, I.: Nerve excitation. New experimental evidence for the macromolecular hypothesis. In: Actualités neurophysiologiques, vol. 10. Trends in neurophysiology (A. M. Monnier, ed.), pp. 79–90. Paris: Masson 1974
Tasaki, I., Watanabe, A., Sandlin, R., Carnay, L.: Changes in fluorescence, turbidity and birefringence associated with nerve excication. Proc. nat. Acad. Sci. (Wash.)61, 883–888 (1968)
Tasaki, I., Barry, W., Carnay, L.: Optical and electrophysiological evidence for conformational changes in membrane macromolecules during nerve excitations. In: Physical principles of biological membranes (F. Snell et al., eds.), pp. 17–31. New York: Gordon and Breach 1970
Weibel, E. R.: Stereological techniques for electron microscopical morphometry. In: Principles and techniques of electron microscopy, vol. 3 (M. A. Hayat, ed.), pp. 237–296. New York: Van Nostrand-Reinhold 1973
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von Muralt, A., Weibel, E.R. & Howarth, J.V. The optical spike. Pflugers Arch. 367, 67–76 (1976). https://doi.org/10.1007/BF00583658
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DOI: https://doi.org/10.1007/BF00583658