Cellular and Molecular Neurobiology

, Volume 4, Issue 1, pp 31–41 | Cite as

The axosomatic contacts on the bursting neuron of the snailHelix pomatia. I. ultrastructural features of the axosomatic contacts

  • Larissa M. Koval
  • Nikolai I. Kononenko
  • Galina G. Skibo


  1. 1.

    The analysis of serial ultrathin sections of the RPAI bursting neuron of the snailHelix pomatia reveals the presence of axosomatic contacts on its surface membrane.

  2. 2.

    These contacts have a number of specific features: (a) the presynaptic axon contains synaptic vesicles and electron-dense granules, typical of peptidergic terminals; (b) the terminal part of the axon forms many finger-like processes which invaginate the neuronal soma; (c) the width of the cleft (80 nm) in the area of the contact is larger than that in usual synaptic contacts; and (d) there is a system of lacoons in the region of the axosomatic contact; this system is formed by protrusions of the soma and it accompanies the contact along its extent.

  3. 3.

    It is suggested that the system of lacoons which communicates with the space between the terminal and the soma may serve as a ramified synaptic cleft into which the secretion from the terminal is released. This system may contribute to a considerable prolongation of the time of action of the secretory product on the membrane of the RPAI neuron.


Key words

isolated bursting neuron axosomatic synapse secretion modulation of activity 


Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.


  1. Abraham, A. (1965). Die Structur der Synapsen im Ganglion viscerale vonAplysia californica.Z. Mikrosk. Anat. Forsch. 7396–116.Google Scholar
  2. Barrantes, F. J. (1970). The neuromuscular junctions of a pulmonate mollusc. Ultrastructural study.Z. Zellforsch. 104205–212.Google Scholar
  3. Bocharova, L. S., Kostenko, M. A., Veprintsev, B. N., and Allachverdov, B. L. (1975). Completely isolated molluscan neurones. An ultrastructural study.Brain Res. 101185–198.Google Scholar
  4. Bullock, T. H., and Horridge, G. A. (1965).Structure and Function in the Nervous Systems of Invertebrates, Freeman, San Francisco.Google Scholar
  5. Burchinskaya, L. F. (1972). On the axo-somatic synaptic terminals on the fresh-water gastropodaPlanorbis corneus neurones.Ukrain. Fiziol. Zhurn. 18168–172.Google Scholar
  6. Coggeshall, R. E. (1967). A light and electron microscope study of the abdominal ganglion ofAplysia californica.J. Neurophysiol. 301263–1287.Google Scholar
  7. Cottrell, G. A., and Osborne, N. (1969). A neurosecretory system terminating in theHelix heart.Comp. Biochem. Physiol. 281455–1459.Google Scholar
  8. Coulter, H. D. (1967). Rapid and improved methods for embedding biological tissues in Epon 812 and Araldite 502.J. Ultrastruct. Res. 20346–355.Google Scholar
  9. Elekes, K., Vadasz, I., and Salanki, J. (1979). Ultrastructure of the bimodal pacemaker neuron in the central nervous system ofHelix pomatia.L. Acta Biol. Acad. Sci. Hung. 30317–334.Google Scholar
  10. Gainer, H. (1972a). Effects of experimentally induced diapause on the electrophysiology and protein synthesis patterns of identified molluscan neurons.Brain Res. 39387–402.Google Scholar
  11. Gainer, H. (1972b). Electrophysiological behavior of an endogenously active neurosecretory cell.Brain Res. 39403–418.Google Scholar
  12. Gerschenfeld, H. M. (1963). Observation on the ultrastructure of synapses in some pulmonate molluscs.Z. Zellforsch. 60258–275.Google Scholar
  13. Ifshin, M. S., Gainer, H., and Barker, J. L. (1975). Peptide factor extracted from molluscan ganglia that modulates bursting pacemaker activity.Nature. Lond. 25472–74.Google Scholar
  14. Kiss I. (1979). Functional characteristics of an identified pair of neurons in the CNS of the pond snail (Lymnaea stagnalis L.)J. Malacol. 18489–497.Google Scholar
  15. Kononenko, N. I. (1979a). Modulation of the endogenous electrical activity of the bursting neuron in the snailHelix pomatia. I. The generator of the slow rhythms.Neuroscience 42037–2045.Google Scholar
  16. Kononenko, N. I. (1979b). Modulation of the endogenous electrical activity of the bursting neuron in the snailHelix pomatia. II. The membrane characteristics related to modulation of the endogenous activity of the neuron.Neuroscience 42047–2055.Google Scholar
  17. Kononenko, N. I. (1979c). Modulation of the endogenous electrical activity of the bursting neuron in the snailHelix pomatia. III. A factor modulating the endogenous electrical activity of the bursting neuron.Neuroscience 42055–2061.Google Scholar
  18. Lederis, K. (1965). An electron-microscopical study of the human neurohypophysis.Z. Zellforsch. 65847–868.Google Scholar
  19. Mayorova, V. F., and Troitskaya, L. P. (1972). Axo-somatic synapses in pedal ganglia of the Gastropoda molluscLymnaea stagnalis.Dokl. Akad. Nauk USSR 2041471–1472.Google Scholar
  20. Nemecek, S.,et al. (1978).Introduction to Neurobiology, Edition of the Medical Literature, Avicenum, Prague, p. 413.Google Scholar
  21. Pogorelaya, N. K., Elekes, K., and Kiss, I. (1977). Electron microscopic investigation of a giant neuron identified in the right parietal ganglion ofLymnaea stagnalis L.Acta Biol. Acad. Sci. Hung. 28451–460.Google Scholar
  22. Sakharov, D. A. (1974).The Genealogy of Neurons, Nauka, Moskva, p. 183 (Russian).Google Scholar
  23. Strumwasser, F. (1965). The demonstration and manipulation of circadian rhythm in a single neuron. InCircadian Clocks (Aschoff, J., Ed.), North-Holland, Amsterdam, pp. 442-465.Google Scholar
  24. Theodosis, T. D., Burect, C., Bludier, J. L., and Dreifuss, J. J. (1978). Morphology of membrane changes during neurohypophyseal hormone release in the hibernating rodent.Brain Res. 154371–376.Google Scholar
  25. Vollrath, L. (1969). Uber die Herkunft “synaptischer” Blaschen in neurosekretotischen Axonen.Z. Zellforsch. 99146–152.Google Scholar
  26. Wendelaar Bonga, S. E. (1970). Ultrastructure and histochemistry of neurosecretory cells and neurohaemal areas in the pond snailLymnaea stagnalis (L).Z. Zellforsch. 108190–225.Google Scholar
  27. Zs-Nagy, I. (1964). Electron-microscopic observations on the cerebral ganglion of the fresh water mussel (Anodonta cygnea L.).Ann. Biol. Tihany 31147–152.Google Scholar
  28. Zs-Nagy, I., and Sakharov, D. A. (1969). Axo-somatic synapses in procerebrum of Gastropoda.Experientia 25258–259.Google Scholar
  29. Zs-Nagy, I., and Sakharov, D. A. (1970). The fine structure of the procerebrum of pulmonate molluscsHelix andLimax.Tissue Cell 2399–411.Google Scholar

Copyright information

© Plenum Publishing Corporation 1984

Authors and Affiliations

  • Larissa M. Koval
    • 1
  • Nikolai I. Kononenko
    • 1
  • Galina G. Skibo
    • 1
  1. 1.Department of General Physiology of the Nervous System, A. A. Bogomoletz Institute of PhysiologyAcademy of Sciences of the Ukraininan S.S.R.KievU.S.S.R.

Personalised recommendations