Summary
The ependymal cells of the toad subcommissural organ produce pale and dense secretory granules. Both types of granules are mainly concentrated in the apical cytoplasm and in the perinuclear region. Pale and dense granules are synthesized by and packed in the rough endoplasmic reticulum, bypassing the step of the Golgi apparatus. The apical cytoplasm of some subcommissural ependymal cells protrudes into the ventricle. All the cells project a few cilia and numerous slender, long microvilli into the ventricular lumen.
Contacting the cilia and the microvilli there is a filamentous material identical to that observed in the fibre of Reissner at the aqueduct of Sylvius. In addition to filaments, the fibre of Reissner contains vacuolar formations. The fibre is surrounded by numerous ependymal cilia, some of which are embedded in the filamentous material of the fibre.
The presence of numerous microvilli projected into the ventricle and the large number of vesicles scattered in the supranuclear cytoplasm seem to indicate that the subcommissural organ may have absorption functions. The fact that the intercellular space of the ependymal layer of the subcommissural organ is not separated from the ventricular lumen by tight junctions but by zonulae adhaerentes could indicate that the cerebrospinal fluid penetrates these intercellular spaces bathing all sides of the ependymal cells. The presence in the ependymal cells of vesicles opening into the intercellular space would be in agreement with the latter possibility.
There are some ultrastructural differences between the ependymal cells of the cephalic end of the subcommissural organ and those of the caudal end. A critical analysis of Reissner's fibre formation is made.
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References
Afifi, A. K.: The subcommissural organ of the camel. J. comp. Neurol. 123, 139–145 (1964).
Altner, H.: Untersuchungen an Ependym und Ependymorganen im Zwischenhirn niederer Wirbeltiere (Neoceratodus, Urodelen, Anuren). Z. Zellforsch. 84, 102–140 (1968).
Bargmann, W., Schiebler, T. H.: Histologische und cytochemische Untersuchungen am Subcommissuralorgan von Säugern. Z. Zellforsch. 37, 583–596 (1952).
Brightman, M. W., Palay, S. L.: The fine structure of ependyma in the brain of the rat. J. Cell Biol. 19, 415–439 (1963).
Bugnon, C., Lenys, R., Lenys, D.: Quelques aspects particuliers de l'organe sous-commissural du Rat blanc et quelques observations sur l'organe sous-commissural du Lapin, du Porc et du Cheval. Ann. Sci. Univ. Besançon, 2e Série, Méd. 7, 61–80 (1963).
Campos-Ortega, J. A.: Aportaciones al estudio histológico del órgano subcomisural del Lebistes reticulatus (Peters). Arch. esp. Morfol. 18, 209–227 (1964).
Dendy, A.: On a pair of ciliated grooves in the brain of the ammocoete, apparently serving to promote the circulation of the fluid in the brain cavity. Proc. roy. Soc. Serie B 69, 485–494 (1902).
Gomez-Bosque, P., Benito Arranz, S., Arnaiz, S.: L'organe sous-commissural chez Cavia cobaya adulte. Acta anat. (Basel) 33, 65–75 (1958).
Hofer, H.: Beobachtungen an dem sogenannten „Supracommissuralen Organ“ (Fuse) und am Recessus mesocoelicus der Primaten. Folia primat. 5, 190–200 (1967).
Isomäki, A. M., Kivalo, E., Talanti, S.: Electron-microscopic structure of the subcommissural organ in the calf (Bos taurus) with special references to secretory phenomena. Ann. Acad. Sci. fenn. A 5 111, 3–64 (1965).
Kohno, K.: Electron microscopic studies on Reissner's fiber and the ependymal cells in the spinal cord of the rat. Z. Zellforsch. 94, 565–573 (1969).
Leather-land, J. F., Dodd, J. M.: Studies on the structure, ultrastructure and function of the subcommissural organ-Reissner's fibre complex of the european eel Anguilla anguilla L. Z. Zellforsch. 89, 533–549 (1968).
Löfgren, F.: On an absorptive ability of the subcommissural organ. A model test. Acta Univ. Lund, Sect. II, No 29, 3–12 (1965).
Mazzi, V.: Caratteri secretori nelle cellule dell' organo sottocommissurale dei Vertebrati inferiori. Arch. Zool. ital. 37, 445–464 (1952).
Müller, H., Sterba, G.: Elektronenmikroskopische Untersuchungen des Subcommissuralorgans von Lampetra planeri (Bloch). Zool. Anz., Suppl. 29, 441–453 (1966).
Murakami, M., Ban, F., Aiura, S.: Histologische Studien des Subcommissuralorgans des Gecko japonicus. Kurume med. J. 4, 8–17 (1957).
—, Tanisaki, T.: An electron microscopic study on the toad subcommissural organ. Arch. Histol. Japon. 23, 337–358 (1963).
Naumann, W.: Histologische Untersuchungen am Subcommissuralorgan und am Reissnerschen Faden von Lampetra planeri (Bloch). Z. Zellforsch. 87, 571–591 (1968).
Okada, M.: On the secretory pathway of the subcommissural organ. Arch. histol. Japon. 9, 199–204 (1955).
Oksche, A.: Über die Art und Bedeutung sekretorischer Zelltätigkeit in der Zirbel und im Subcommissuralorgan. Verh. anat. Ges. (Jena) 52, 88–96 (1954).
—: Funktionelle histologische Untersuchungen über die Organe des Zwischenhirndaches der Chordaten. Anat. Anz. 102, 404–419 (1956).
—: Vergleichende Untersuchungen über die sekretorische Aktivität des Subkommissuralorgans und den Gliacharakter seiner Zellen. Z. Zellforsch. 54, 549–612 (1961).
—: Histologische, histochemische und experimentelle Studien am Subkommissuralorgan von Anuren (mit Hinweisen auf den Epiphysenkomplex). Z. Zellforsch. 57, 240–326 (1962).
—: The subcommissural organ. J. Neuro-Visc. Relat., Suppl. 2, 111–139 (1969).
—, Vaupel-von Harnack, M.: Elektronenmikroskopische Untersuchungen an den Nervenbahnen des Pinealkomplexes von Rana esculenta L. Z. Zellforsch. 68, 389–426 (1965).
Olsson, R.: The subcommissural organ. Thesis. Stockholm 1958.
Papacharalampous, N. X., Schwink, A., Wetzstein, R.: Elektronenmikroskopische Untersuchungen am Subcommissuralorgan des Meerschweinchens. Z. Zellforsch. 90, 202–229 (1968).
Rodríguez, E. M.: Fixation of the central nervous system by perfusion of the cerebral ventricles with a threefold aldehyde mixture. Brain Res. 15, 395–412 (1969).
—: Ependymal specialization III. Ultrastructural aspects of the basal secretion of the toad subcommissural organ. Z. Zellforsch. 111, 32–50 (1970).
Stanka, P., Schwink, A., Wetzstein, R.: Elektronenmikroskopische Untersuchungen des Subkommissuralorgans der Ratte. Z. Zellforsch. 63, 277–301 (1964).
Sterba, G.: Incorporation of sulphur-35 into the subcommissural organ and Reissner's fibre in Cyprinus carpio. Nature (Lond.) 216, 504 (1867).
—, Müller, H., Naumann, W.: Fluoreszenzund elektronenmikroskopische Untersuchungen über die Bildung des Reissnerschen Fadens bei Lampetra planeri (Bloch). Z. Zellforsch. 76, 355–376 (1967).
Stutinsky, F.: Colloide, corps de Herring et substance Gomori positive de la neurohypophyse. C.R. Soc. Biol. (Paris) 144, 1357–1360 (1950).
Talanti, S.: Studies on the subcommissural organ in some domestic animals. Ann. Med. exp. Fenn. 36, Suppl. No 9, 1–97 (1958).
—: Studies on the subcommissural organ of the bovine fetus. Anat. Rec. 134, 473–490 (1959).
Wislocki, G. B., Leduc, E. H.: The cytology and histochemistry of the subcommissural organ and Reissner's fiber in the rodents. J. comp. Neurol. 97, 515–544 (1952).
—: The cytology of the subcommissural organ, Reissner's fiber, periventricular glial cells and posterior collicular recess of the rat's brain. J. comp. Neurol. 101, 283–309 (1954).
—, Roth, W. D.: Selective staining of the human subcommissural organ. Anat. Rec. 130, 125–133 (1958).
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This investigation was partially supported by a Grant of the Wellcome Trust Foundation.
Fellow of the Consejo Nacional de Investigaciones Científicas y Técnicas de la República Argentina. The author wishes to thank the valuable help of Mr. P. Heap.
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Rodríguez, E.M. Ependymal specializations. Z. Zellforsch. 111, 15–31 (1970). https://doi.org/10.1007/BF00342098
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DOI: https://doi.org/10.1007/BF00342098