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Acta Biologica Hungarica

, Volume 59, Supplement 2, pp 209–219 | Cite as

Do Glial Cells Exist in the Nervous System of Parasitic and Free-Living Flatworms? An Ultrastructural and Immunocytochemical Investigation

  • Natalia M. BiserovaEmail author
Article

Abstract

It is still unclear whether flatworms have specialized glial cells. At present there are no special methods available for the identification of glial cells in flatworms. The aim of this research was to carry out detailed investigations of the CNS in two species of cestodes, and to get an idea whether these cells may fit into the concept of glia. Three types of glial cells have been found in Grillotia erinaceus: (1) fibroblast- like cells in the cerebral ganglion (CG); (2) glial cells in bulbar nerves with filaments and laminar cytoplasm; (3) a 3rd type of cells forms multilayer envelopes in the main cords (MC); also they make contacts with the excretory epithelium. To demonstrate the existence of glial cells, an immunocytochemical and ultrastructural investigation of Ligula intestinalis was undertaken. Intensive S100b-like immunoreaction (IR) was found in the GG and in the MC. IR-varicosities were mostly located asymmetrically on the MC, and no IR was found in neuropiles. Small glial cells were found on the surface of the MC; they have oval nuclei and dense cytoplasm with slim processes going around the neuropile and enclosing neurons. Long junctions are seen between cell processes but with neurons they usually possess juxtaposition contacts. Glial cells lack vesicles or synapse-like structures. Intensive S100b-like-IR has been shown in the CNS of cestodes for the first time. Results from ultrastructural research support the immunocytochemical date.

Keywords

Glia flatworms S100b ultrastructure immunocytochemistry 

Abbreviations

A

axon

CG

cerebral ganglion

GAx

giant axon

EX

excretory vessel and cells

F

fibrillar matrix

GC

glial cell

GP

glial processes

InM

invaginations of the neuron membrane

M

muscle cells and processes

MC

main nerve cord

Mh

mitochondria

N

neuron

NP

nervous processes

npl

neuropile

Nu

nucleus

L

lipid drop

sy

synapse

T

tegument and subtegument

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References

  1. 1.
    Bedini, C., Lanfranchi, A. (1998) Ultrastructural study of the brain of a Typhloplanid flatworm. Acta Zool (Stock). 79, 243–249.CrossRefGoogle Scholar
  2. 2.
    Biserova, N. (2000) The ultrastructure of glia-like cells in lateral nerve cords of adult Amphilina foliacea (Amphilinida). Acta Biol. Hung.. 51, 439–442.PubMedGoogle Scholar
  3. 3.
    Biserova, N. (2000) Do glia cells exist in parasitic flatworms? Europ. J. Neurosci. 12, 11, 354.Google Scholar
  4. 4.
    Biserova, N., Korneva, J. (2006) The nervous system ontogeny in cestodes and amphilinids. Invertebrate Zool.. 3, 157–184.CrossRefGoogle Scholar
  5. 5.
    Biserova, N., Salnikova, M. (2002) The ultrastructure of main lateral nerves cords and associated cell elements in Triaenophorus nodulosus (Cestoda: Pseudophyllidea). Cytologia. 44, 611–622.Google Scholar
  6. 6.
    Bockerman, I., Reuter, M., Timoshkin, O. (1994) Ultrastructural study of the central nervous system of endemic Geocentrophora (Prorhynchida, Platyhelmintes) from Lake Baikal. Acta Zool. (Stockh). 75, 47–55.CrossRefGoogle Scholar
  7. 7.
    Coles, J. A., Abbott, N. J. (1997) Signaling from neurons to glial cells in invertebrates. General Pharmacology: The Vascular System. 29, 39–47.CrossRefGoogle Scholar
  8. 8.
    Cooper, M. (1996) Intercellular signaling in neuronal-glial networks. Brain Research. 716, 53–58.CrossRefGoogle Scholar
  9. 9.
    Ferrero, E., Lanfranchi, A., Bedini, C. (1985) An ultrastructural account of otoplanid Turbellaria neuroanatomy. I. The cerebral ganglion and the peripheral nerve net. Acta Zool. (Stockh). 66, 63–74.CrossRefGoogle Scholar
  10. 10.
    Golubev, A. (1982) Electron Microscopy of the Nervous System in Worms. Kazan. Publishing house of the Kazan State University.Google Scholar
  11. 11.
    Halton, D., Gustafsson, M. (1996) Functional morphology of the platyhelminth nervous system. Parasitology. 113, 47–72.CrossRefGoogle Scholar
  12. 12.
    Halton, D., Maule, A., Shaw, C. (1997) Trematode Neurobiology. In: Fried, B., Graczyk, Th. (eds) Advances in Trematode Biology. CRC Press. N.Y. pp. 345–381.Google Scholar
  13. 13.
    Koopowitz, H. (1986) On the evolution of central nervous systems: Implications from polyclad turbellarian neurobiology. Hydrobiologia. 132, 79–87.CrossRefGoogle Scholar
  14. 14.
    Michetti, F., Cocchia, D. (1982) S-100-like immunoreactivity in a planarian. Cell Tissue Res.. 223, 575–582.CrossRefGoogle Scholar
  15. 15.
    Pentreath, V. (1989) Invertebrate glial cells. Comp. Biochem. Physiol. A 93. 1, 77–83.CrossRefGoogle Scholar
  16. 16.
    Reuter, M. (1990) From innovation to integration. Trends of the integrative system in microturbellarias. In: Gustafsson, M., Reuter, M. (eds) The Early Brain. Åbo Acad. Press, pp. 161–178.Google Scholar
  17. 17.
    Riehl, B., Schlue, W. (1998) Morphological organization of neuropile glial cells in the central nervous system of the medicinal leech (Hirudo medicinalis). Tissue and Cell. 30, 177–186.CrossRefGoogle Scholar
  18. 18.
    Rohde, K. (1971) Untersuchungen an Multicotyle purvisi Daves, 1941 (Trematoda: Aspidogastrea). III. Licht- und elektronmikroskopischer Bau des Nervensystems. Zool. Jahrb. Anat.. 88, 320–363.Google Scholar
  19. 19.
    Rohde, K., Webb, R. (1986) Ultrastructure of neuroglia in the peripheral nervous system of Temnocephala sp. (Turbellaria, Temnpcephalida). Zool. Anz.. 216, 53–57.Google Scholar
  20. 20.
    Sukhdeo, S., Sukhdeo, M. (1994) Mesenchyme cells in Fasciola hepatica (Platyhelminthes): primitive glia? Tissue and Cell. 26, 123–131.CrossRefGoogle Scholar

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© Akadémiai Kiadó, Budapest 2008

This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made.

Authors and Affiliations

  1. 1.Department of Invertebrate Zoology, Biological FacultyMoscow State UniversityMoscowRussia
  2. 2.Institute for Biology of Inland WatersRussian Academy of ScienceBorok, YaroslavlRussia

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