Are there differences between proseriates and lower flatworms in ultrastructure of the nervous system? (original) (raw)

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Abstract

The ultrastructure of the CNS (central nervous system) in three species of the Proseriata — Archiloa unipunctata (O. Fabricius), Bothriomolus balticus (Meixner), and Promonotus schultzei (Meixner) — was studied and compared to that of the ‘lower flatworms’ Stenostomum leucops (Catenulida) and Microstomum lineare (Macrostomida) in material available from our previous studies. Conventional electron microscopical fixation was used for A. unipunctata and B. balticus; the tannic-acid-incubation method (TARI), a method that reveals especially nonsynaptic exocytotic release of neuronal substances, was applied in study of P. schultzei.

In general, the ultrastructural features of neurons and nerve fibers were similar in proseriates and lower flatworms. A striking feature common to both groups was the secretory appearance of all neurons. A significant difference between them is the occurrence, in the proseriates, of wrapping of neurons by glial cells. Heterogeneity in the population of neuronal vesicles and in structure of synapses in the proseriates are probably advanced characters; by contrast, S. leucops has relatively homogeneous vesicles and simple synapses. A gradual advancement from the state in the catenulids through that in the macrostomids to the proseriates seems to be reflected in the differentiation of synapses and the variability of neuronal vesicles. This probably reflects differences in functional demands but also evolutionary advancement.

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References

• Buma, P., Roubos, E. W. & R. M. Buijs, 1984. Ultrastructural demonstration of exocytosis of neural, neuroendocrine and endocrine secretions with an in vitro tannic acid (TARI-)method. Histochemistry 80: 247–256.
  Google Scholar
• Ferrero, E. A., A. Lanfranchi & C. Bedini, 1985. An ultrastructural account of otoplanid Turbellaria neuroanatomy. I. The cerebral ganglion and the peripheral nerve net. Acta Zool. (Stockh.) 66: 63–74.
  Google Scholar
• Golubev, A. I., 1988. Glia and neuroglia relationships in the central nervous system of the Turbellaria. (Electron microscopic data). Fortschr. Zool. 36: 31–37.
  Google Scholar
• Lane, N. J., D. B. Sattelle & L. A. Hufnagel, 1983. Presynaptic and postsynaptic structures in the insect central nervous system; intra-membraneous features and sites of alpha bungaro toxin binding. Tissue & Cell 15: 921–938.
  Google Scholar
• Luft, J. H., 1961. Improvements in epoxy embedding techniques. J. biophys. biochem. Cytol. 9: 409–414.
  Google Scholar
• Reisinger, E., 1925. Untersuchungen am Nervensystem der Bothrioplana semperi Braun. Z. Morph. Ökol. Tiere 5: 119–149.
  Google Scholar
• Reisinger, E., 1970. Zur Problematik der Evolution der Coelomaten. Z. zool. Syst. Evolutionsforsch. 8: 81–109.
  Google Scholar
• Reuter, M., 1981. The nervous system of Microstomum lineare (Turbellaria, Macrostomida). II. The ultrastructure of synapses and neurosecretory release sites. Cell Tissue Res. 218: 375–387.
  Google Scholar
• Reuter, M., M. Wikgren & I. Palmberg, 1980. The nervous system of Microstomum lineare (Turbellaria, Macrostomida). I. A fluorescence and electron microscopic study. Cell Tissue Res. 211: 31–40.
  Google Scholar
• Reuter, M. & I. Palmberg, 1990. Synaptic and nonsynaptic release in Stenostomum leucops — a study of the nervous system and sensory receptors. Acta Acad. Aboensis Ser. B. 50(7): 121–136.
  Google Scholar
• Rieger, R. M., 1981. Morphology of the Turbellaria at the ultrastructural level. Hydrobiologia 84: 213–229.
  Google Scholar
• Rieger, R. M., S. Tyler, J. P. S. Smith, III & G. E. Rieger, 1990. Platyhelminthes: Turbellaria. In F. W. Harrison & B. J. Bogitsh (eds), Platyhelminthes and Rhynchocoela, Vol. 3 in F. W. Harrison (ed), Microscopic anatomy of invertebrates. Wiley-Liss, New York: 7–140.
  Google Scholar
• Rohde, K. & R. Webb, 1986. Ultrastructure of neuroglia in the peripheral nervous system of Temnocephala sp. (Turbellaria, Temnocephalida). Zool. Anz. 216: 53–57.
  Google Scholar
• Trawicki, W., A. Czubaj & J. Moraczewski, 1988. The brain ultrastructure of Dendrocoelum lacteum (O. F. Müller). Fortschr. Zool. 36: 195–200.
  Google Scholar
• Watson, A. H. D. & M. Burrows, 1988. Distribution and morphology of synapses and nonspiking local interneurons in the thoracic nervous system of the locust. J. comp. Neurol. 272: 605–616.
  Google Scholar

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Authors and Affiliations

1. Department of Biology, Åbo Akademi University, SF 20500, Åbo, Finland
   Maria Reuter

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Reuter, M. Are there differences between proseriates and lower flatworms in ultrastructure of the nervous system?.Hydrobiologia 227, 221–227 (1991). https://doi.org/10.1007/BF00027605

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• Issue date: December 1991
• DOI: https://doi.org/10.1007/BF00027605

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