Nervous system of the snailHelix aspersa

III. Electron microscopic study of neurosecretory nerves and endings in the ganglionic sheath
  • Juan Fernández
  • M. Soledad Fernández


The fine structure of neurosecretory nerves and endings associated with the sheath of the infraesophageal ganglion ofHelix aspersa is described. The sheath is a neurohemal organ whose vascularized stroma receives both monoaminergic and peptidergic endings. The latter occur along the surface of the nerves or scattered within the stroma. They include a complex population of vesicular profiles. The granular vesicles (1300–3000 Å in diameter) exhibit structural modifications that may be related to the intra-axonal release of their neurohormones. The agranular vesicles (500–2000 Å in diameter) occur in large numbers and lie mostly adjacent to the axon surface. Synaptoid specializations seem to represent active sites for the extracellular discharge of neurosecretory material. The monoaminergic endings so far studied lack synaptoid specializations and contain small granular (800–1300 Å in diameter) and agranular (700 Å in diameter) vesicles. Two kinds of non-neural cells are associated with the nerves: glial cells and melanocytes.

Key words

Neurosecretory nerves Glial and pigment cells Neural sheath Gastropods Ultrastructure 


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  1. Bargmann, W., Gaudecker, B. von: Über die Ultrastruktur neurosekretorischer Elementargranula. Z. Zellforsch.96, 495–504 (1969).Google Scholar
  2. Benjamin, P. R.: Myoneural junctions in the connective tissue sheath of a molluscan ganglion. Nature (Lond.)219, 1371–1372 (1968).Google Scholar
  3. Bindler, E., La Bella, F. S., Sanwall, M.: Isolated nerve endings (Neurosecretosomes) from the posterior pituitary. Partial separation of Vasopressin and Oxytocin and the isolation of Microvesicles. J. Cell Biol.34, 185–205 (1967).Google Scholar
  4. Birbeck, M. S. C.: Electron microscopy of melanocytes: the fine structure of hair-bulb premelanosomes. Ann. N.Y. Acad. Sci.100, 540–547 (1963).Google Scholar
  5. Breathnach, A. S., Pointz, S. V.: Electron microscopy of pigment cells in tail skin ofLacerta vivipara. J. Anat. (Lond.)100, 549–569 (1966).Google Scholar
  6. Bunt, A. H.: Formation of coated and “synaptic” vesicles within neurosecretory axon terminals of the crustacean sinus gland. J. Ultrastruct. Res.28, 411–421 (1969).Google Scholar
  7. Bunt, A. H., Ashby, E. A.: Ultrastructure of the sinus gland of the crayfishProcambarus clarkii. Gen. comp. Endocr.9, 334–342 (1967).Google Scholar
  8. Coggeshall, R. E.: A light and electron microscope study of the abdominal ganglion ofAplysia californica. J. Neurophysiol.30, 1263–1287 (1967).Google Scholar
  9. Coggeshall, R. E., Kandel, E. R., Kupfermann, I., Waziri, R.: A morphological and functional study on a cluster of identifiable neurosecretory cells in the abdominal ganglion ofAplysia californica. J. Cell Biol.31, 363–368 (1966).Google Scholar
  10. Cottrell, G. A., Osborne, N. N.: Subcellular localization of serotonin in an identified serotonin containing neuron. Nature (Lond.)225, 470–472 (1970).Google Scholar
  11. Dean, C. R., Hope, D. B.: The isolation of Neurophysin-I and -II from bovine pituitary neurosecretory granules separated on a large scale from other subcellular organelles. Biochem. J.106, 565–573 (1968).Google Scholar
  12. De Robertis, E.: Histophysiology of Synapses and Neurosecretion. New York: The Mac Millan Co. 1964.Google Scholar
  13. Fernández, J.: Nervous system of the snailHelix aspersa. I. Structure and histochemistry of ganglionic sheath and neuroglia. J. comp. Neurol.127, 157–181 (1966a).Google Scholar
  14. Fernández, J.: Submicroscopic organization of the sheath surrounding ganglia and nerves ofHelix aspersa. Anat. Rec.154, 345 (1966b).Google Scholar
  15. Fernández, J.: Nervous system of the snailHelix aspersa. II. Fine structure of vascular channels and amebocytes associated with the ganglionic sheath. Z. Zellforsch.118, 512–524 (1971).Google Scholar
  16. Frazier, W. T., Kandel, E. R., Kupfermann, I., Waziri, R., Coggeshall, R. E.: Morphological and functional properties of identified neurons in the abdominal ganglion ofAplysia californica. J. Neurophysiol.30, 1288–1351 (1967).Google Scholar
  17. Gerschenfeld, H. M.: Observations on the ultrastructure of synapses in some pulmonate molluscs. Z. Zellforsch.60, 258–275 (1963).Google Scholar
  18. Hökfelt, T., Jonsson, G.: Studies on reaction and binding of monoamines after fixation and processing for electron microscopy with special reference to fixation with potassium permanganate. Histochemie16, 45–67 (1968).Google Scholar
  19. Kobayashi, H., Oota, Y., Uemura, H., Hirano, T.: Electron microscopic and pharmacological studies on the rat median eminence. Z. Zellforsch.71, 387–404 (1966).Google Scholar
  20. Kuhlmann, D.: Vergleichende fluoreszenzmikroskopische und elektronenmikroskopische Untersuchungen am zentralen Nervensystem vonPlanorbarius corneus L. (Basommatophora). Z. Zellforsch.110, 131–152 (1970).Google Scholar
  21. La Bella, F. S., Sanwall, M.: Isolation of nerve endings from the posterior pituitary gland. Electron microscopy of fractions obtained by centrifugation. J. Cell Biol.25, 179–193 (1965).Google Scholar
  22. Lederis, K.: The fine structure and hormone content of the hypothalamo-neurohypophyseal system of the rainbow trout (Salmo irideus) exposed to sea water. Gen. comp. Endocr.4, 638–661 (1964).Google Scholar
  23. Moyer, F. H.: Genetic effects on melanosome fine structure and ontogeny in normal and malignant cells. Ann. N.Y. Acad. Sci.100, 584–606 (1963).Google Scholar
  24. Moyer, F. H.: Genetic variations in the fine structure and ontogeny of mouse melanin granules. Amer. Zoologist.6, 43–66 (1966).Google Scholar
  25. Nagasawa, J., Douglas, W. W., Schultz, R. A.: Ultrastructural evidence of secretion by exocytosis and of “synaptic vesicle” formation in posterior pituitary glands. Nature (Lond.)227, 407–409 (1970).Google Scholar
  26. Nisbet, R. H., Plummer, J. M.: Further studies on the fine structure of the heart ofAchatinidae. Proc. malac. Soc. Lond.37, 199–208 (1966).Google Scholar
  27. Nolte, A.: Neurohaemal „Organe“ bei Pulmonaten (Gastropoda). Zool. Jb. Abt. Anat. u. Ontog.82, 365–380 (1965).Google Scholar
  28. Pentreath, V. W., Cottrell, G. A.: The blood supply to the central nervous system ofHelix pomatia. Z. Zellforsch.111, 160–178 (1970).Google Scholar
  29. Rinne, U. K.: Ultrastructure of the median eminence of the rat. Z. Zellforsch.74, 98–122 (1966).Google Scholar
  30. Rodríguez, E. M.: Ultrastructure of the neurohaemal region of the toad median eminence. Z. Zellforsch.93, 182–212 (1969).Google Scholar
  31. Rogers, D. C.: Fine structure of smooth muscle and neuromuscular junctions in the optic tentacles ofHelix aspersa andLimax flavus. Z. Zellforsch.89, 80–94 (1968).Google Scholar
  32. Rogers, D. C.: Fine structure of smooth muscle and neuromuscular junctions in the foot ofHelix aspersa. Z. Zellforsch.99, 315–335 (1969a).Google Scholar
  33. Rogers, D. C.: Fine structure of the epineural connective tissue sheath of the subesophageal ganglion ofHelix aspersa. Z. Zellforsch.102, 99–112 (1969b).Google Scholar
  34. Rosenbluth, J.: The visceral ganglion ofAplysia californica. Z. Zellforsch.60, 213–236 (1963).Google Scholar
  35. Sanchis, C. A., Zambrano, D.: The structure of the central nervous system of a pulmonate mollusc (Cryptomphalus aspersa). I. Ultrastructure of the connective epineural sheath. Z. Zellforsch.94, 62–71 (1969).Google Scholar
  36. Scharrer, B.: Neurosecretion. XIII. The ultrastructure of the corpus cardiacum of the insectLeucophaea maderae. Z. Zellforsch.60, 761–796 (1963).Google Scholar
  37. Scharrer, B.: The stromal element in endocrine organs of insects. Proceed. VIIIth. Internat. Congr. Anat., Wiesbaden p. 107. August, 1965.Google Scholar
  38. Scharrer, B.: Neurosecretion. XIV. Ultrastructural study of sites of release of neurosecretory material inBlattarian insects. Z. Zellforsch.89, 1–16 (1968).Google Scholar
  39. Scharrer, B., Kater, S. B.: Neurosecretion. XV. An electron miscroscopic study of the Corpora cardiaca ofPeriplaneta americana after experimentally induced hormone release. Z. Zellforsch.95, 177–186 (1969).Google Scholar
  40. Shivers, R. R.: Possible sites of release of neurosecretory granules in the sinus gland of the crayfish,Orconectes nais. Z. Zellforsch.97, 38–44 (1969).Google Scholar
  41. Simpson, L.: Morphological studies of possible neuroendocrine structures inHelisoma tenue (Gastropoda Pulmonata). Z. Zellforsch.102, 570–593 (1969).Google Scholar
  42. Simpson, L., Bern, H. A., Nishioka, R. S.: Survey of evidence for neurosecretion in gastropod molluscs. Amer. Zoologist.6, 123–138 (1966).Google Scholar
  43. Smith, U.: The origin of small vesicles in neurosecretory axons. Tissue and Cell.2, 427–433 (1970).Google Scholar
  44. Smith, U.: Uptake of ferritin into neurosecretory terminals. Phil. Trans. B261, 391–394 (1971).Google Scholar
  45. Smith, U., Smith, D. S.: Observations on the secretory processes in the corpus cardiacum of the stick insect,Carausius morosus. J. Cell Sci.1, 59–66 (1966).Google Scholar
  46. Zambrano, D., De Robertis, E.: Ultrastructure of the peptidergic and monoaminergic neurons in the hypothalamic neurosecretory system of anuran batracians. Z. Zellforsch.90, 230–244 (1968).Google Scholar

Copyright information

© Springer-Verlag 1972

Authors and Affiliations

  • Juan Fernández
    • 1
  • M. Soledad Fernández
    • 1
  1. 1.Departamento de Biología, Facultad de CienciasUniversidad de ChileSantiagoChile

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