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Ultrastructural studies on the hypothalamic neurosecretory neurones of the rat

I. The paraventricular neurones of the non-treated rat


The ultrastructural features of the paraventricular neurones of the non-treated rat are presented comparing them with those of the supraoptic neurones. No striking differences are seen between the general electron microscopic characteristics of the paraventricular and supraoptic neurones.

The importance of adequate fixation to obtain good preservation of the neurones is emphasized, since inadequate fixation can cause e.g. artefactual appearance of “dark neurones”. The previously presented classification of the neurosecretory neurones into two categories (e.g. “light and dark neurones”) on the basis of the number of ribosomes is not considered justifiable, since their number can vary to a very great extent even within a single cell.

The synthesis of neurosecretory products in the paraventricular neurones obviously follows the general mode of the synthesis of secretory proteins: ribosomes—RER—Golgi complex—secretory vesicles.

On the basis of the localization of heavy metal deposits after osmium impregnation and demonstration of acid phosphatase the Golgi complex of the paraventricular neurones is found to be polarized. The direction of the polarity is discussed.

The substructures of the dense cores of the neurosecretory granules and of the contents of the lysosomal dense bodies are nearly identical. Therefore it is considered impossible to determine positively the nature of the dark condensed material within the Golgi complex. The characteristics of the immature neurosecretory granules and the possibility of releasing neurosecretory products into the cytoplasm already within the perikarya are speculated.

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  1. Anderson, P. J.: Purification and quantitation of glutaraldehyde and its effect on several enzyme activities in skeletal muscle. J. Histochem. Cytochem.15, 652–661 (1967).

  2. Arstila, A. U.: Unpublished observations 1970.

  3. Bara, D., Bartok, I., Csapó, Z.: Beiträge zur Ultrastruktur der hypothalamischen Neurosekretion. Endokrinologie53, 385–396 (1968).

  4. Beams, H. W., Kessel, R. G.: The golgi apparatus: Structure and function. Int. Rev. Cytol.23, 209–276 (1968).

  5. Bisset, G. W., Clark, B. J., Haldar, J.: Blood levels of oxytocin and vasopressin during suckling in the rabbit and the problem of their independent release. J. Physiol. (Lond.)206, 711–723 (1970).

  6. Bohman, S.-O., Maunsbach, A.: Effects on tissue fine structure of variations in colloid osmotic pressure of glutaraldehyde fixatives. J. Ultrastruct. Res.30, 195–208 (1970).

  7. Boissonnas, R. A., Guttmann, S. T.: Chemistry of the neurohypophysial hormones. In: Handbuch der experimentellen Pharmakologie, Band XXIII, Neurohypophysial hormones and similar polypeptides, p. 40–66. Berlin-Heidelberg-New York: Springer 1968.

  8. Boudier, J. L., Boudier, J. A., Picard, D.: Ultrastructure du lobe postérieur de l'hypophyse du rat et ses modifications au cours de l'excrétion de vasopressine. Z. Zellforsch.108, 357–380 (1970).

  9. Brooks, C. M., Ishikawa, T., Koitzumi, K., Lu, H.-H.: Activity of neurones in paraventricular nucleus of the hypothalamus and its control. J. Physiol. (Lond.)182, 217–231 (1966).

  10. Cammermeyer, J.: An evaluation of the significance of the dark neurone. Ergebn. Anat. Entwickl.-Gesch.36, 1–61 (1962).

  11. Duve, C. de: The lysosome in retrospect. In: Lysosomes in biology and pathology 1 (J. T. Dingle and H. B. Fell, eds.), p. 3–40. Amsterdam and London: North-Holland Publ. Co. 1969.

  12. Diepen, R.: Der Hypothalamus. In: Handbuch der mikroskopischen Anatomie des Menschen, IV/7. Berlin-Göttingen-Heidelberg: Springer 1962.

  13. Duggan, A. W., Reed, G. W.: Hypothalamus and oxytocin. Nature (Lond.)181, 1278–1279 (1958).

  14. Dyball, R. E. J.: Electrical discharge pattern in hypothalamic neurosecretory neurones associated with hormone release. In: Aspects of neuroendocrinology (W. Bargmann and B. Scharrer, eds.), p. 151–158. Berlin-Heidelberg-New York: Springer 1970.

  15. Eneström, S.: Nucleus supraopticus. A morphological and experimental study in the rat. Acta path. microbiol. scand., Suppl.186, 1–99 (1967).

  16. Ericsson, J. L. E., Trump, B. F.: Observations on the application to electron microscopy of the lead phosphate technique for the demonstration of acid phosphatase. Histochemie4, 470–487 (1965).

  17. Friend, D. S., Murray, M. J.: Osmium impregnation of the golgi apparatus. Amer. J. Anat.117, 135–150 (1965).

  18. Grove, S. N., Bracker, C. E., Morré, D. J.: Cytomembrane differentiation in the endoplasmic reticulum-golgi apparatus-vesicle complex. Science161, 171–173 (1968).

  19. Holtzman, E., Novikoff, A. B., Villaverde, H.: Lysosomes and GERL in normal and chromatolytic neurons of the rat ganglion nodosum. J. Cell Biol.33, 419–435 (1967).

  20. Jones, G. W., Pickering, B. T.: Rapid transport of neurohypophysial hormones in the hypothalamo-neurohypophysial tract. J. Physiol. (Lond.)208, 73p-75p (1970).

  21. Jongkind, J. F., Swaab, D. F.: The distribution of thiamine diphosphate-phosphohydrolase in the neurosecretory nuclei of the rat following osmotic stress. Histochemie11, 319–324 (1967).

  22. Kalimo, H., Arstila, A. U.: The effect of different osmolarities of the rinsing solutions on the ultrastructure of aldehyde-fixed tissue. J. Ultrastruct. Res. (in press).

  23. - Lehtimäki, M.: Serial embedding procedure for electron microscopy. J. Ultrastruct. Res. (in press).

  24. Karlsson, U., Schultz, R. L.: Fixation of the central nervous system for electron microscopy by aldehyde perfusion I. J. Ultrastruct. Res.12, 160–186 (1965).

  25. LaBella, F. S.: Storage and secretion of neurohypophyseal hormones. Canad. J. Physiol. Pharmacol.46, 335–345 (1968).

  26. Lederis, K.: The distribution of vasopressin and oxytocin in hypothalamic nuclei. Mem. Soc. Endocr.12, 227–239 (1962).

  27. McNeilly, A. S., Folley, S. J.: Blood levels of milk-ejection activity (oxytocin) in the female goat during mating. J. Endocr.48, ix-x (1970).

  28. Mugnaini, E.: “Dark cells” in electron micrographs from the central nervous system of vertebrates. J. Ultrastruct. Res.12, 235–236 (1965).

  29. Murakami, M., Nakayama, Y., Shimida, T., Hirita, S.: Ultrastrukturelle Veränderungen des supraoptico-hypophysären Systems der Ratte nach Aldosteronbehandlung. Endokrinologie56, 18–29 (1970).

  30. Nemetschek-Gansler, H.: Zur Ultrastruktur des Hypophysen-Zwischenhirnsystems der Ratte. Z. Zellforsch.67, 844–861 (1965).

  31. Nibbelink, D. W.: Paraventricular nuclei, neurohypophysis and parturition. Amer. J. Physiol.200, 1229–1232 (1961).

  32. Novikoff, A. B., Shin, W. Y.: The endoplasmic reticulum in the Golgi-zone and its relations to microbodies, Golgi apparatus and autophagic vacuoles in rat liver cells. J. Microscopie3, 187–206 (1964).

  33. Olivecrona, H.: Paraventricular nucleus and pituitary gland. Acta physiol. scand.40, Suppl. 136, 1–178 (1957).

  34. Osinchak, J.: Electron microscopic localization of acid phosphatase and thiamine pyrophosphatase in hypothalamic neurosecretory cells of the rat. J. Cell Biol.21, 35–47 (1964).

  35. Pardoe, A. U., Weatherall, M.: The intracellular localization of oxytocic and vasopressor substances in the pituitary glands of rats. J. Physiol. (Lond.)127, 201–212 (1955).

  36. Peters, A.: The fixation of the central nervous system and the analysis of electron micrographs of the neuropil with special reference to the cerebral cortex. In: Contemporary research methods in neuroanatomy (W. J. H. Nauta and S. O. E. Ebbesson, eds.), p. 56–76. Berlin-Heidelberg-New York: Springer 1970.

  37. Pilgrim, C.: Morphologische und funktionelle Untersuchungen zur Neurosekretbildung. Ergebn. Anat. Entwickl.-Gesch.41, 4, 1–79 (1969).

  38. Rechardt, L.: Electron microscopic and histochemical observations on the supraoptic nucleus of normal and dehydrated rats. Acta physiol. scand., Suppl.329, 1–79 (1969).

  39. Rinne, U. K.: Experimental electron microscopic studies on the neurovascular link between the hypothalamus and anterior pituitary. In: Aspects of neuroendocrinology (W. Bargmann and B. Scharrer, eds.), p. 220–228. Berlin-Heidelberg-New York: Springer 1970.

  40. Sachs, H.: Neurosecretion. Advanc. Enzymol.32, 327–372 (1969).

  41. Sokol, H.: Evidence for oxytocin synthesis after electrolytic destruction of the paraventricular nucleus in rats with hereditary diabetes insipidus. Neuroendocrinology6, 90–97 (1970).

  42. —, Valtin, H.: Evidence for the synthesis of oxytocin and vasopressin in separate neurons. Nature (Lond.)214, 314–315 (1967).

  43. Streefkerk, J. G.: Functional changes in the morphological appearance of the hypothalamo-hypophyseal neurosecretory system, and catecholaminergic neural system, and in the adenohypophysis of the rat. Thesis. Vrije Universiteit te Amsterdam, Amsterdam 1967.

  44. Stürmer, E.: Bioassay procedures for neurohypophysial hormones and similar polypeptides. In: Handbuch der experimentellen Pharmakologie, Band XXIII, Neurohypophysial hormones and similar polypeptides, p. 130–189. Berlin-Heidelberg-New York: Springer 1968.

  45. Trump, B. F.: Personal communication 1970.

  46. Underwood, E. E.: Particle-size distribution. In: Quantitative microscopy (R. T. DeHoff and F. N. Rhines, eds.), p. 149–200. New York: McGraw-Hill Book Co. 1968.

  47. Venable, J. H., Coggeshall, R.: A simplified lead citrate stain for use in electron microscopy. J. Cell Biol.25, 407–408 (1965).

  48. Watson, M. L.: Staining of tissue sections for electron microscopy with heavy metals. J. biophys. biochem. Cytol.4, 475–478 (1958).

  49. Webster, H. DeF., Ames, A. III: Glutaraldehyde fixation of central nervous tissue: an electron microscopic evaluation in isolated rabbit retina. Tissue & Cell1, 53–63 (1969).

  50. Zambrano, D., de Robertis, E.: The secretory cycle of supraoptic neurons in the rat. A structural-functional correlation. Z. Zellforsch.73, 414–431 (1966).

  51. — —: Ultrastructural aspects of the inhibition of neurosecretion by puromycin. Z. Zellforsch.76, 458–470 (1967a).

  52. — —: Ultrastructure of the hypothalamic neurosecretory system of the dog. Z. Zellforsch.81, 264–282 (1967b).

  53. — —: The effect of castration upon the ultrastructure of the rat hypothalamus I. Supraoptic and paraventricular nuclei. Z. Zellforsch.86, 487–498 (1968).

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This study was supported by a grant from the Emil Aaltonen Foundation, Tampere. I express my best thanks to Docent Antti U. Arstila, Head of the Laboratory of Electron Microscopy, and Professor Urpo K. Rinne, Head of the Department of Neurology, for the guidance of this work.

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Kalimo, H. Ultrastructural studies on the hypothalamic neurosecretory neurones of the rat. Z.Zellforsch 122, 283–300 (1971).

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  • Paraventricular nucleus
  • Rat
  • Synthesis of hormones
  • Acid phosphatase
  • Osmium impregnation
  • Neurosecretion