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  • 1985-1989
  • 1980-1984  (3)
  • 1983  (3)
  • 1
    ISSN: 1432-0533
    Keywords: Synapse ; Dentritic spine ; Purkinje cell ; Neuronal compensation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary This study was undertaken to elucidate morphological changes in the synaptic area of the Purkinje cell dendritic spines when granule cells were decreased in number. The mice were injected s. c. with 30 mg/kg b. w. of cytosine arabinoside on days 2, 3, and 4, and on days 7, 8 and 9, and were designated as group I and group II, respectively. The mice injected with saline on days 2, 3, and 4 served as control. The cerebella of the mice in each group were examined by electron microscopy on days 30, 60, and 90. Using photographs thus obtained, the synaptic length and area of Purkinje cell dendritic spines which participated in synapses with axons of granule cells were measured by computer. In the controls, these spines did not increase significantly either in synaptic length or in spine area in the duration from 30 to 90 days after birth. In the 90-day-old mice belonging to group I and group II, however, they increased by about 20% in the synaptic length and by about 35% in the spine area as compared to those in age-matched control. The elongation and enlargement show that the synaptic surface on the spine spreads to compensate for synapses lost by reduction in number of granule cells in experimental groups.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Acta neuropathologica 59 (1983), S. 41-47 
    ISSN: 1432-0533
    Keywords: Cytosine arabinoside ; Cerebellum ; External granular layer ; Purkinje cell ; Heterotopic granule cell
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary This study was undertaken to elucidate the relationship between the time of destruction of the external granular layer and subsequent cerebellar abnormalities. Mice were injected s. c. with 30 mg/kg body weight (b. wt.) of cytosine arabinoside on days 2, 3, and 4, on days, 4, 5, and 6, on days 7, 8, and 9, and on days 10, 11, and 12, and designated as group I, II, III, and IV, respectively. In group I, disarrangement of Purkinje cells and heterotopic granule cells in the molecular layer were observed on all lobes of cerebellum. Heterotopic granule cells were seen on all lobes in group II, whereas disarrangement of Purkinje cells was observed only in the region from the anterior to middle lobes. In group III, heterotopic granule cells were limited to the area from anterior to middle lobes, but there was no disarrangement of Purkinje cells. Group IV cerebellum did not show abnormal cytoarchitecture. Golgi-Cox studies showed abnormal arborization of Purkinje cells in each experimental group. They were arbitrarily classified into inverted Purkinje cells, lying Purkinje cells, T-shaped Purkinje cells, and poorly arborized Purkinje cells. The earlier the postnatal treatment the more severe were the abnormalities of Purkinje cell dendrite. According to the electron-microscopic study, some glomerular synaptic complexes, which are normally confined to the internal granular layer, were observed even in the molecular layer in groups I, II, and III. Some of the Purkinje cell dentritic spines did not make synapses with parallel fibers in any of the experimental groups. The results indicate that severity of abnormal arborization of Purkinje cells is dependent on the period of destruction of the external granular layer. Formation of heterotopic granule cells was dependent on the destruction of the external granular layer up to day 10 after birth.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1432-0533
    Keywords: Ultrastructure ; Fetus ; Nervous system ; GM1-gangliosidosis type 1
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The nervous system of a 22-week-old fetus with GM1-gangliosidosis type 1 was studied by electron microscopy. The tissues thus examined were the cerebral cortex at the parietal region, the cerebellum, the thoracic spinal cord, the Auerbach's myenteric plexus in the large intestine and the radial nerve fibers. In the cerebral cortex, membrane-bound vacuoles, which occasionally contained stacks of fine fibrils, were observed in the large young neurons in the deeper part of the cortical plate. The neurons in the other part of the cerebral cortex carried no storage materials. In the cerebellum, the membrane-bound vacuoles with stacks of fine fibrils were seen only in the Purkinje cells. The neurons in the spinal cord also contained several zebra-like bodies and the above membrane-bound vacuoles. As for the peripheral nervous system (PNS), neurons in the Auerbach's myenteric plexus carried membranous cytoplasmic bodies and zebra-like bodies. Some of the axons in the radial nerve fibers also contained a lot of pleomorphic electron-dense bodies and a few membranous cytoplasmic ones. These results show that the accumulation of storage materials is started in the large neurons which are produced in the early stage of neurogenesis in the central nervous system (CNS). Additionally, the observed membrane-bound vacuoles are considered to be structures which occur before the membranous cytoplasmic bodies and/or the zebra-like bodies. It is also elucidated that the PNS is affected earlier than the cerebral and cerebellar cortices and thoracic spinal cord.
    Type of Medium: Electronic Resource
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