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Volume 62 (1985 - 198･･･
- Issue 6 Pages 365-
- Issue 5 Pages 231-
- Issue 3-4 Pages 133-
- Issue 2 Pages 67-
- Issue 1 Pages 1-
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Volume 62, Issue 6
Displaying 1-3 of 3 articles from this issue
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Akira TOKUNAGA, Katsumi OTANI, Shoei SUGITA, Katsutoshi TERASAWA1986 Volume 62 Issue 6 Pages 365-383
Published: 1986
Released on J-STAGE: September 24, 2012
JOURNAL FREE ACCESSQuantitative morphological changes in the superior colliculus (SC) and the parabigeminal nucleus (PB) were studied in hereditary unilaterally microphthalmic rats. The mutant animals have one vestigial and one almost normally developed eyeball. The former eye completely lacks the optic nerve. The proportion of uncrossed to crossed retinal fibers in the mutant rats was estimated at about 6%. Conspicuous changes in SC were found only on the contralateral side of the abnormal eye. Relative volume of the superficial layers of SC (SCS)to the central gray matter (SGC) was decreased to 50% of the normal. However, the cell density in SCS increased up to 130-190% of the normal. The str. griseum superficiale consisted mainly of small roundish neurons in dense and irregular arrangements. Small amounts of fibers were observed in the medial 1/3 of the str. opticum, but very few in the lateral 2/3. No significant changes were found in the deeper collicular layers of the mutant rats.
Unilaterally microphthalmic PB was subdivided normally into three parts: the dorsal (PBd), middle (PBm) and ventral subdivisions (PBv). The relative volumes of each PB subdivision on both sides had decreased to 57 to 65% of the normal, except for that of PBv on the contralateral side to the anomalous eye (26% of the normal). Cell densities of PB were slightly lowered (76-84% of the normal) in PBm and PBv, but not much in PBd (88-90% of the normal)on both sides.View full abstractDownload PDF (6917K) -
Shigeki HIRANO, Toshio SHIRAI1986 Volume 62 Issue 6 Pages 385-397
Published: 1986
Released on J-STAGE: September 24, 2012
JOURNAL FREE ACCESSIt was observed by a scanning electron microscopy that the migration and aggregation process of the neural crest cells to form the spinal ganglia in the space between the neural tube and the somites in salamander larvae.
When the neural crest cells began to migrate, they projected their thick cytoplasmic processes along the dorse-lateral wall of the neural tube. Completing their migration in the space between the neural tube and the somites, the neural crest cells changed their shape to flattend polygonal and formed a sheet in this space. After the migration of the neural crest cells the sclerotome cells invaded into this space from the ventral area upward. At that time the cell sheet formed by the neural crest cells was segmentally divided corresponding to the somites. Thereafter a thick cell layer was formed by the neural crest cells and the sclerotome cells. But the distribution pattern of each cell in this layer could not be recognized. Subsequently the cell group formed the spinal ganglion appeared the metameric arrangement in this layer. Finally each cell group became the compact cell mass as the spinal ganglion.
These findings showed that in hynobius larvae the neural crest cells developed into a spinal ganglion may have the unspecified migrated pathway from the neural crest to the site of the spinal ganglion and aggregate through the period of the cell sheet.View full abstractDownload PDF (8630K) -
IV. Electron Microscopic StudyYoshiro INOUE, Mitsuko IGUCHI, Mitsuhiro TAKEDA, Kaoru INOUE, Toshio T ...1986 Volume 62 Issue 6 Pages 399-419
Published: 1986
Released on J-STAGE: September 24, 2012
JOURNAL FREE ACCESSThe glioarchitectonics of the chicken brain were studied by electron microscopy, following light microscopic studies (Inoue 1970.1971. Inoue et al.1971.1973) and light and electron microscopic study on the chicken optic nerve (Inoue et al.1976a). The results obtained were as follows.
1. Three types of glial elements, that is, astrocytes, oligodendrocytes and microglia, could be identified, as was done by light microscopy. Atypical glial cells with fine, multiple processes and stained only by the Golgi method (Inoue etal.1973) were not clearly identified from the electron microscopic structure, but were inferred to be a subtype of the oligodendrocytes.
2. The three elements of glial cells were almost identical in terms of fine structure with those in the experimental mammalian central nervous system, described previously by many investigators. Astrocytes in the gray matter containing few myelinated nerve fibers, however, hardly processed those glial filaments that were characteristic in this type of cell in the mammalian brain.
3. All three types of glial elements could function as perineuronal satellite glial cells, whose cell bodies were closely apposed to the neuronal perikaryon. Between the plasma membranes of the neuronal soma and glial one, patches filled with electron dense material in the intercellular cleft occurred in various places, and, except for microglia, desmosome-like structures were often formed between the neuronal and glial elements.
4. Pericytes were sometimes in direct contact with the neuropil through the opened portion of the vascular basal lamina, and similarity between the cytoplasmic expansions of some microglia and pericytes could be recognized. Thus, the idea that microglia might be derived from the vascular wall cells or from mesenchymal cells could not be denied on the basis of the present study.View full abstractDownload PDF (14424K)
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