Summary
The ultrastructure of the afferent synapse in hair cells of the lateral line-canal organ was studied using different fixation and staining techniques. Glutaraldehyde-fixed tissue without post-osmication, contrasted by section staining with uranyl acetate and lead citrate, was compared with (a) osmium tetroxide-fixed tissue followed by the same staining procedure, and with (b) glutaraldehyde-fixed tissue, block-impregnated with phosphotungstic acid (PTA). The results reveal a pronounced heterogeneity in the composition of the synaptic body, reflecting regional differences in chemical affinity to the fixatives and staining agents. It is proposed that the “intracleft substance”, the synaptic structure defined by the PTA staining technique, is actually due to the glutaraldehyde fixation procedure and is apparently the outer leaflet of the postsynaptic membrane. A special technique that allows alternate sections of a series to be differentially stained for electron microscopy is proposed.
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Akert, K., Pfenninger, K., Sandri, C., Moor, H.: Freeze etching and cytochemistry of vesicles and membrane complexes in synapses of the central nervous system. In: Structure and Function of Synapses (Pappas, G.D. and Purpura, D.P., ed.), pp. 67–86. New York: Raven Press 1972
Benshalom, G., Flock, Å.: Calcium-induced electron density in synaptic vesicles of afferent and efferent synapses on hair cells in the lateral line organ. Brain Res. 121, 173–178 (1977)
Bloom, F.E.: The formation of synaptic functions in developing rat brain. In: Structure and Function of Synapses (Pappas, G.D. and Purpura, D.P., ed.), pp. 101–120. New York: Raven Press 1972
Bloom, F.E., Aghajanian, G.K.: Cytochemistry of synapses: selective staining for electron microscopy. Science 154, 1575–1577 (1966)
Bloom, F.E., Aghajanian, G.K.: Fine structural and cytochemical analysis of the staining of synaptic junctions with phosphotungstic acid. J. Ultrastruct. Res. 22, 361–375 (1968)
Bondareff, W., Sjöstrand, J.: Cytochemistry of synaptosomes. Exp. Neurol. 24, 450–458 (1969)
Bunt, A.H.: Enzymatic digestion of synaptic ribbons in amphibian retinal photoreceptors. Brain Res. 25, 571–577 (1971)
Cold Spring Harbor Symposia on Quantitative Biology. Volume XL, The Synapse, Cold Spring Harbor Laboratory 1976
Flock, Å.: Electron microscopic and electrophysiologic study on the lateral line canal organ. Acta Otolaryngol. Suppl. (Stockh.) 199, 1–90 (1965)
Flock, Å., Jørgensen, M., Russell, I.: The physiology of individual hair cells and their synapses. In: Basic Mechanisms in Hearing (by Møller, A.R., ed.), pp. 273–306. New York and London: Academic Press 1973
Gleisner, L., Flock, Å., Wersäll, J.: The ultrastructure of the afferent synapse on hair cells in the frog labyrinth. Acta Otolaryngol. (Stockholm) 76, 199–207 (1973)
Gulley, R.L., Reese, T.S.: Freeze-fracture studies on the synapses in the organ of Corti. J. Comp. Neurol. 171, 517–544 (1977)
Hama, K., Saito, K.: Fine structure of the afferent synapse of hair cells in the saccular macula of the goldfish, with special reference to the anastomosing tubules. J. Neurocytol. 6, 361–373 (1977)
Jones, D.G.: Some factors affecting the PTA staining of synaptic junctions. Z. Zellforsch. 143, 301–312 (1973)
Karlsson, U., Schultz, R.L.: Fixation of the central nervous system for electron microscopy by aldehyde perfusion. J. Ultrastruct. Res. 12, 160–186 (1965)
Mullinger, A.M.: The fine structure of ampullary electric receptor in Amiurus. Proc. Roy. Soc. Lond. Series B 160, 345–359 (1964)
Nakajima, Y., Wang, D.W.: Morphology of afferent and efferent synapses in hearing organ of the goldfish. J. Comp. Neurol. 156, 403–416 (1974)
Ogawa, K., Hirano, H., Saito, T., Ago, Y.: Ultracytochemistry of intracellular membranes. I. Findings obtained by an in situ phosphotungstic acid staining. Ultracytochemistry sine osmium tetroxide. Arch. Histol. Jpn. 31, 209–222 (1970)
Osborne, M.P., Thornhill, R.A.: The effect of monoamine depleting drugs upon synaptic bar in the inner ear of the bullfrog (Rana catesbeiana). Z. Zellforsch. 127, 347–355 (1972)
Oschman, J.L., Wall, B.J.: Calcium binding to intestinal membranes. J. Cell. Biol. 55, 58–73 (1972)
Palade, G.E.: A study of fixation for electron microscopy. J. Exp. Med. 95, 285–298 (1952)
Pfenninger, K.H.: The cytochemistry of synaptic densities. I. An analysis of the bismuth iodide impregnation method. J. Ultrastruct. Res. 34, 103–122 (1971)
Reynolds, E.S.: The use of lead citrate at high pH as an electron-opaque stain in electron microscope. J. Cell Biol. 17, 208–213 (1963)
Rhodin, J.: Correlation of ultrastructure, organization and function in normal and experimentally changed proximal convoluted tubuli cells of the mouse kidney. Dissertation, Karolinska Institute. Aktiebolaget Godvil, Stockholm 76 (1954)
Sabatini, D.D., Bensch, K., Barrnett, R.J.: Cytochemistry and electron microscopy. The preservation of cellular ultrastructure and enzymatic activity by aldehyde fixation. J. Cell Biol. 17, 19–58 (1963)
Schultz, R.L., Karlsson, U.: Fixation of the central nervous system for electron microscopy by aldehyde perfusion. J. Ultrastruct. Res. 12, 187–206 (1965)
Sternberger, L.A.: Enzyme immunocytochemistry. In: Electron Microscopy of Enzymes (edited by Hayat, M.A.), Vol. 1, pp. 105–191, New York: Van Nostrand Reinhold Company 1973
Vollrath, L., Howe, C.: Light and drug induced changes of epiphysial synaptic ribbons. Cell Tissue Res. 165, 383–390 (1976)
Wagner, H.J.: Darkness-induced reduction of the number of synaptic ribbons in fish retina. Nature, New Biol. 246, 53–55 (1973)
Watson, M.L.: Staining of tissue sections for electron microscopy with heavy metals. J. Biophys. Biochem. Cytol. 4, 475–479 (1958)
Westrum, L.E., Lund, R.P.: Formalin perfusion for correlative light- and electron-microscopical studies of the nervous system. J. Cell Sci. 1, 229–238 (1966)
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This research was carried out at the King Gustaf V Research Institute, Stockholm, Sweden
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Benshalom, G. Ultrastructure of an excitatory synapse. Cell Tissue Res. 200, 291–298 (1979). https://doi.org/10.1007/BF00236421
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DOI: https://doi.org/10.1007/BF00236421