Summary
The present study deals with the electron microscopic observations on the softshelled turtle paraventricular organ, with special reference to the relationship of the ependymal cells and the so-called albuminous substances. It is shown that the so-called albuminous substances consist of the tips of neuronal processes extending into the ventricular lumen. They probably arise from the nerve cells lying within the hypendymal or the underlying tissue. The ependymal cells of the PVO themselves are basically similar in structure to those of any other animal.
The processes observed contain two types of vesicles, namely: the clear vesicle, 500 to 1600 Å in diameter, and the cored vesicle, measuring 600 to 1500 Å in diameter, which has a distinct membrane enclosing an extremely dense core of variable sizes. The functional significance of these vesicles is discussed in relation to that of inclusions in the neurosecretory and the autonomic nerve fibers in the hypothalamus.
The findings indicate that in the terminal endings of the processes a production or formation of vesicles might occur and that these vesicles might be discharged into the cerebrospinal fluid by microapocrine secretion.
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References
Agduhr, E.: Über ein zentrales Sinnesorgan (?) bei den Vertebraten. Z. Anat. Entwickl.gesch. 66, 223–360 (1922).
Araki, Ch.: The present condition of studies on the hypophysial neurosecretion (Japanese). Saishin Igaku Sosetsu Sosho 1, 1–7 (1948).
Bargmann, W.: Elektronenmikroskopische Untersuchungen an der Neurohypophyse. In: Zweites Internat. Symposium über Neurosekretion (Hrsg. W. Bargmann, B. Hanström u. B. Scharrer u. E. Scharrer, S. 1–11. Berlin-Göttingen-Heidelberg: Springer 1958.
—, u. A. Knoop: Über die morphologischen Beziehungen des neurosekretorischen Zwischenhirnsystems zum Zwischenlappen der Hypophyse (Licht- und elektronenmikroskopische Beobachtungen). Z. Zellforsch. 52, 256–277 (1960).
—, u. E. Scharrer: The site of origin of the hormones of the posterior pituitary. Amer. Scientist 39, 255–259 (1951).
Blinzinger, K., N. B. Newcastle, and H. Hager: Observations on prismatic type of mitochondria within astrocytes of the syrian hamster brain. J. Cell Biol. 25, 293–303 (1965).
Brightman, M. W., and S. L. Palay: The fine structure of ependyma in the brain of the rat. J. Cell Biol. 19, 419–439 (1963).
Charlton, H. H.: A gland-like organ in the brain. Anat. Rec. 29, 352 (1925).
—: A gland-like ependymal structure in the brain. Proc. kon. ned. Akad. Wet. 31, 823–836 (1928).
De Iraldi, A. P., H. F. Dugan, and E. de Robertis: Adrenergic synaptic vesicles in the anterior hypothalamus of the rat. Anat. Rec. 145, 521–531 (1963).
Dierickx, K.: The dendrites of the preoptic neurosecretory nucleus of Rana temporaria and the osmoreceptor. Arch. int. Pharmacodyn. 140, 708–725 (1962).
Dixon, W. E.: Pituitary secretion. J. Physiol. (Lond.) 57, 129–138 (1923).
Fleischhauer, K.: Untersuchungen am Ependym des Zwischen- und Mittelhirn der Landschildkröte (Testudo graeca). Z. Zellforsch. 46, 729–767 (1957).
Gerschenfeld, H. M., J. H. Tramezzani, and E. de Robertis: Ultrastructure and function in neurohypophysis of the toad. Endocrinology 66, 741–762 (1960).
Holmes, R. L., and J. A. Kiernan: The fine structure of the infundibular process of the hedgehog. Z. Zellforsch. 61, 894–912 (1964).
—, and F. G. W. Knowles: “Synaptic vesicles” in the neurohypophysis. Nature (Lond.) 185, 710–711 (1960).
Ito, H.: The receptor in the ventricular wall of the reptilian brain. J. Hirnforsch. 6, 333–337 (1964).
—: The neurosecretory apparatus in the ventricular wall of the reptilian brain. J. Hirnforsch. 7, 493–498 (1965).
Kappers, Ariëns C. U., C. Huber, and E. C. Crosby: The comparative anatomy of the nervous system of vertebrates including man, vol. 1 and II. New York: Macmillan 1936.
Kitamura, T.: Electron microscopic studies on the carpal organ of the pig. Arch. histol. jap. 14, 575–610 (1958).
Knowles, F. G. W.: The ultrastructure of a crustacean neurohemal organ. In: Neurosecretion, p. 71–78. New York and London: Academic Press 1962.
—: Techniques in the study of neurosecretion. In: Techniques in endocrine research (eds. P. Eckstein and F. G. W. Knowles), p. 57–65. New York and London: Academic Press 1963.
Kolmer, W.: Über einen supraependymalen Nervenplexus in dem Hirnventrikel der Affen. Z. Anat. Entwickl.-Gesch. 93, 182–187 (1930).
Kurosumi, K., T. Iijima, and T. Kitamura: Electron microscopic studies on the human axillary apocrines sweat glands. Arch. histol. jap. 16, 523–566 (1959).
Kurotsu, T.: Über den Nucleus magnocellularis paraventricularis bei Reptilien und Vögeln. Proc. kon. ned. Akad. Wet. 38, 784–797 (1935).
Kylin, E.: Über die Sekretion der Hypophyse. Acta med. scand. 85, 457–472 (1935).
Laruelle, M. L.: Le système végétatif médio-diencéphalique. 1. Partie anatomique. Rev. neurol. 41, 808–888 (1934).
Lederis, K.: Ultrastructure of the hypothalamo-neurohypophysial system in teleost fishes and isolation of hormone-containing granules from the neurohypophysis of the cod (Gadus morrhua). Z. Zellforsch. 58, 192–213 (1962).
—: A preliminary report on the fine structure of the human neurohypophysis. J. Endocr. 27, 133–135 (1963).
—: The fine structure and hormone content of the hypothalamo-neurohypophysial system of the rainbow trout (Salmo irideus) exposed to sea water. Gen. comp. Endocr. 4, 638–661 (1964).
—: An electron microscopical study of the human neurohypophysis. Z. Zellforsch. 65, 847–868 (1965).
Legait, E. J.: Les organes épendymaires du troisième ventricule. Thèse Univ. Nancy, Nancy 1942. Cit. from Vigh et al.
Luft, J. H.: Improvements in Epoxy resin embedding methods. J. biophys. biochem. Cytol. 9, 409–414 (1961).
Masai, H.: Receptor in hypothalamus. Med. J. Osaka Univ. 2, 185–188 (1951).
Matsumoto, S.: Zytologische Studien über das Ependym. 1. Teil. Über die Gehirnventrikel (speziell das Zwischenhirn- u. das Mittelhirnventrikel) bei den Reptilien und Amphibien (Japanese, Germ. abstr.). Acta anat. Nippon 8, 956–971 (1936a).
—: Zytologische Studien über das Ependym. II. Teil. Histologische Untersuchungen der sog. speziellen Lokalitäten des Ependyms (Japanese, Germ. abst.). Acta anat. Nippon 9, 320–327 (1936b).
—: Zytologische Studien über das Ependym. III. Teil. Feinere Struktur der sog. speziellen Lokalitäten des Ependyms (Japanese, Germ. abst.). Acta anat. Nippon 9, 1107–1120 (1936c).
Murakami, M., and T. Tanizaki: An electron microsocpic study on the toad subcommissural organ. Arch. histol. jap. 23, 337–358 (1963).
Palay, S. L.: The fine structure of the neurohypophysis. In: Progress in Neurobiology. II. Ultrastructure and cellular chemistry of neuronal tissue (eds. S. Korey and J. J. Nürnberger), p. 31–49. New York: Hoeber 1957.
Papez, J. W.: Thalamus of turtles and thalamic evolution. J. comp. Neurol. 61, 433–475 (1935).
Rodríguez, E. M.: Neurosecretory system of the toad Bufo arenarum Hensel and its changes during inanition. Gen. comp. Endocr. 4, 684–695 (1964).
Roussy, G., et M. Mosinger: Les corrélations épiphyso-hypophysaires. Ann. Anat. path. 15, 847–858 (1938).
Seto, H., and K. Funahashi: Human ependyma as a sensory organ. Arch. histol. jap. 7, 131–141 (1955).
Shimizu, N., and S. Ishii: Electron microscopic observations of catecholamine-containing granules in the hypothalamus and area postrema and their changes following reserpine injection. Arch. histol. jap. 34, 489–497 (1964).
Smoller, C. G.: Neurosecretory processes extending into the third ventricle; secretory or sensory?. Science 194, 882–884 (1965).
Trendelenburg, P.: Weitere Untersuchungen über Gehalt des Liquor cerebrospinalis an wirksamen Substanzen des Hypophysenhinterlappens. Naunyn-Schmiedebergs Arch. exp. Path. Pharmak. 114, 255–261 (1926).
Vigh, B., B. Aros, P. Zaránd, I. Törk, and T. Wenger: Ependymal neurosecretion. II. The Gomori-positive secretion in the paraventricular organ and the ventricular ependyma in different vertebrates. Acta morph. Acad. Sci. hung. 11, 335–350 (1962).
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The author's grateful thanks are due to Prof. E. Yamada for his continuously kind guidances and due to Prof. T. Sakurai for his constant encouragement.
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Takeichi, M. The fine structure of ependymal cells part II: An electron microscopic study of the soft-shelled turtle paraventricular organ, with special reference to the fine structure of ependymal cells and so-called albuminous substance. Zeitschrift für Zellforschung 76, 471–485 (1967). https://doi.org/10.1007/BF00339749
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DOI: https://doi.org/10.1007/BF00339749