Summary
The corpora pedunculata of the wood ant (Formica lugubris Zett.) consist of two sharply defined layers: The perikaryon layer and the subjacent neuropil. Synaptic endings are found exclusively in the neuropil. The synapses consist of a central, presynaptic end knob of 1.2–2.5 μ diameter and a relatively large number of surrounding postsynaptic processes of 0.3–1.1μ diameter. These junctions are analogous to axodendritic synapses of the vertebrates. The presynaptic process contains mitochondria and a multitude of light vesicles (300–600 Å diameter). Larger vesicles 700–1000 Å with a dark center are seen more rarely. The synaptic cleft has a diameter of approximately 130 Å and varies somewhat with different fixation methods. With glutaraldehyde-osmium fixation, this relatively wide gap is maintained only in circumscribed areas of the junction, while in adjacent areas it tends to contract and an “external compound membrane” is formed. The postsynaptic region is characterized by the presence of a subsynaptic network which is revealed only by suitable fixation methods. This and the persistent synaptic cleft are the main structural differentiations found in junctional areas thus far.
Cholinesterase is located with the aid of thiolacetic acid (Barnett) and Eserin control studies. The enzyme is found in the cytoplasm immediately adjacent to the pre- and postsynaptic membranes. In two thirds of our observations the reaction is far more concentrated postsynaptically than presynaptically. In one third, the distribution is reversed. Only an insignificant amount of cholinesterase is present within the synaptic cleft. There is no evidence that cholinesterase is evenly distributed along the entire junctional region. In contrast, only small circumscribed areas show a positive reaction and these coincide with the extent of the synaptic cleft and the subsynaptic network. Such areas seem to correspond to the “active junctional areas”.
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Literatur
Arnold, W. J.: Structural organization in the neuropil of the Periplaneta brain. J. Cell Biol. 23, 6 A (1964).
Barnett, R. J.: The fine structural localization of acetylcholin-esterase at the myoneuronal junction. J. Cell Biol. 12, 247–262 (1962).
Basurmanova, O. K.: Distinctive features of fine structure of the conducting elements of cerebral ganglion in insects. Fed. Proc. Transl., Suppl. 23, T 1177–T 1180 (1964).
Brown, L. M.: A thiocholine method for locating cholinesterase activity by electron microscopy. Bibl. anat. (Basel) 2, 21–33 (1960).
Buchholz Ch.: Elektronenmikroskopische Befunde am bestrahlten Oberschlundganglion der Odonaten-Larven (Colopteryx splendens Haar.). Z. Zellforsch. 63, 1–21 (1964).
Colhoun, E. H.: The physiological significance of acetylcholine in insects and observations upon other pharmacologically active substances. In: J. W. L. Beament, J. E. Treherne and V. B. Wigglesworth (eds.) Advances in insect physiology I. London: Academic Press 1963.
Couteaux, R.: Principaux critères morphologiques et cytochimiques utilisables aujourd'hui pour définir les divers types de synapses. Actualités neurophysiol. 3, 145–173 (1961).
—: The differentiation of synaptic areas. Proc. roy. Soc. B 158, 457–480 (1963).
Dalton, A. J.: A chrome-osmium fixative for electron microscopy. Anat. Rec. 121, 281 (1955).
DeLorenzo, A. J. D.: Electron microscopy of the cerebral cortex: I. The ultrastructure and histochemistry of synaptic junctions. Bull. Johns Hopk. Hosp. 108, 258–279 (1961).
DeRobertis, E.: Submicroscopic morphology of the synapse. Int. Rev. Cytol. 8, 61–96 (1959).
—: Electron microscope and chemical study of binding sites of brain biogenic amines. In: H. E. Himwich and W. A. Himwich (eds.) Biogenic Amines. Progress in brain research, vol. 8. Amsterdam: Elsevier 1964a.
—: Histophysiology of synapses and neurosecretion. Oxford: Pergamon Press 1964 b.
—, A.Pellegrino de Iraldi, G. Rodriguez de Lores Arnaiz, and L. Salganicoff: Electron microscope observations on nerve endings isolated from rat brain. Anat. Rec. 139, 220–221 (1961).
Gray, E. G.: Tissue of the central nervous system. In: S. M. Kurtz (ed.) Electron microscopic anatomy. New York: Academic Press 1964.
—, and V. P. Whittaker: The isolation of nerve endings from brain: An electron-microscopic study of cell fragments derived by homogenization and centrifugation. J. Anat. (Lond.) 96, 79–88 (1962).
Guthrie, D. M.: Observations on the nervous system of the flight apparatus in the locust Schistocerca gregaria. Quart. J. micr. Sci. 105, 183–201 (1964).
Hess, A.: The fine structure of nerve cells and fibers, neuroglia, and sheaths of the ganglion chain in the cockroach. J. biophys. biochem. Cytol. 4, 731–742 (1958).
Iyatomi, K., and K. Kanehisa: Localization of cholinesterases in the American cockroach. Jap. J. appl. Entomol. Zool. 2, 1–10 (1958).
Karlsson, U., and R. Schultz: Plasma membrane apposition in the central nervous system after aldehyde perfusion. Nature (Lond.) 201, 1230–1231 (1964).
— —: Fixation of the central nervous system for electron microscopy by aldehyde perfusion. I. Preservation with aldehyde perfusates versus direct perfusion with osmium tetroxide with special reference to membranes and the extracellular space. J. Ultrastruct. Res. 12 160–186 (1955).
Karnovsky, M.J.: Simple methods for “staining with lead” at high pH in electron microscopy. J. biophys. biochem. Cytol. 11, 729–732 (1961).
—: The localization of cholinesterase activity in rat cardiac muscle by electron microscopy. J. Cell. Biol. 23, 217–232 (1964).
Koelle, G. B.: The histochemical identification of acetylcholinesterase in cholinergic, adrenergic and sensory neurons. J. Pharmacol. exp. Ther. 114, 167–184 (1955).
—: A new concept of the neurohumoral functions of acetylcholine and acetylcholinesterase. J. Pharm. Pharmacol. 14, 65–90 (1962).
Landolt, A. M.: Elektronenmikroskopische Untersuchungen an der Zellkörperschicht der Corpora pedunculata von Waldameisen (Formica lugubris Zett.) mit besonderer Berücksichtigung der Neuron-Glia-Beziehung. Z. Zellforsch. 66, 701–736 (1965).
-, and H. Ris: Electron microscopic studies on somasomatic interneuronal junctions in the corpus pedunculatum of the wood ant (Formica lugubris Zett.). J. Cell Biol. (1966) (in press).
Lehrer, G. M., and L. Ornstein: A diazo coupling method for the electron microscopic localization of cholinesterase. J. biophys. biochem. Cytol. 6, 399–406 (1959).
Lewis, P. R., and C. C. D. Shute: Demonstration of cholinesterase activity with the electron microscope. J. Physiol. (Lond.) 175, 5–7 P (1964).
Luft, J. H.: Improvements in epoxy resin embedding methods. J. biophys. biochem. Cytol. 9, 409–414 (1961).
Palay, S. L.: The morphology of synapses in the central nervous system. Exp. Cell Res., Suppl. 5, 275–293 (1958).
Scharrer, B.: Neurosecretion XIII. The ultrastructure of the corpus cardiacum of the insect Leucophaea maderae. Z. Zellforsch. 60, 761–796 (1963).
Schultz, R. L., and U. Karlsson: Fixation of the central nervous system for electron microscopy by aldehyde perfusion. II. Effect of osmolarity, pH of perfusate, and fixative concentration. J. Ultrastruct. Res. 12, 187–206 (1965).
Smith, D. S., and J. E. Treherne: Functional aspects of the organization of the insect nervous system. In: J. W. L. Beament, J. E. Treherne and V. B. Wigglesworth (eds.) Advances in insect physiology I. London: Academic Press 1963.
Torack, R. M., and R. J. Barnett: Fine structural localization of cholinesterase activity in the rat brain stem. Exp. Neurol. 6, 224–244 (1962).
Trujillo-Cenoz, O.: Study on the fine structure of the central nervous system of Pholus labruscae L. Z. Zellforsch. 49, 432–446 (1959).
—: Some aspects of the structural organization of the arthropod ganglia. Z. Zellforsch. 56, 649–682 (1962).
— and J. Melamed: Electron microscope observations of the insect brain. J. Ultrastruct. Res. 7, 389–398 (1962).
Waser, P. G.: The cholinergic receptor. J. Pharm. Pharmacol. 12, 577–594 (1960).
Watson, M. L.: Staining of tissue sections for electron microscopy with heavy metals. J. biophys. bioohem. Cytol. 4, 475–478 (1958).
Whittaker, V. P.: The separation of subcellular structures from brain tissue. Biochem. Soc. Symposia 23, 109–126 (1963).
—: Investigations on the storage sites of biogenic amines in the central nervous system. In: H. H. Himwich and W. A. Himwich (eds.) Biogenic Amines. Progress in brain research, vol. 8. Amsterdam: Elsevier 1964.
Wigglesworth, V. B.: The distribution of esterase in the nervous system and other tissues of the insect Rhodnius prolixus. Quart. J. micr. Sci. 99, 441–450 (1958).
Zacks, S. I., and J. M. Blumberg: The histochemical localization of acetylcholinesterase in the fine structure of neuromuscular junctions of mouse and human intercostal muscle. J. Histochem. Cytochem. 9, 317–324 (1961).
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Herrn Prof. Dr. W. Bargmann zum 60. Geburtstag gewidmet.
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Landolt, A.M., Sandri, C. Cholinergische Synapsen im Oberschlundganglion der Waldameise (Formica lugubris Zett.). Z.Zellforsch 69, 246–259 (1966). https://doi.org/10.1007/BF00406277
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DOI: https://doi.org/10.1007/BF00406277