Summary
The subpial glial limiting membrane of the cat spinal cord was examined by scanning electron microscopy after disruption of plasma membranes of astrocytes composing this membrane by controlling the fixation time in glutaraldehyde and OsO4. The subpial glial limiting membrane of the spinal cord was principally composed of two layers of astrocytic processes: an upper layer mainly composed of laminated flattened processes and a lower layer mainly composed of thin, cord-like processes. The outermost surface of the limiting membrane immediately beneath the subpial basement membrane was totally lined with flattened, overlapping astrocytic processes. The majority of the flattened processes in the upper layer of the limiting membrane were varied in shape and usually smaller than 5x5 μm2, and the rest of the flattened processes were oval or round, and larger (5–10 μm in diameter) than the majority of the flattened processes. Glomerular structures of tightly packed glial filaments were observed within the superficial flattened processes. These glomerular structures appeared to occupy the central space as a cytoskeletal core. The thin, cord-like processes contained a varying number of glial filaments running parallel to one another to form narrow bundles of filaments. These bundles of filaments coursed obliquely toward the outer surface of the spinal cord where they were transformed into superficial flattened glomerular structures of various forms.
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References
Andres KH (1966) Die Feinstruktur des subduralen Neurothels der Katze (Felis catus L.). Naturwissenschaften 53:204–205
Bondareff W, McLone DG (1973) The external glial limiting membrane in Macaca: Ultrastructure of a laminated glioepithelium. Am J Anat 136:277–296
Braak E (1975) On the fine structure of the external glial layer in the isocortex of man. Cell Tissue Res 157:367–390
Goldman JE (1983) Immunocytochemical studies of actin localization in the central nervous system. J Neurosci 3:1952–1962
Gröschel-Stewart U, Unsicker K, Leonhard H (1977) Immunohistochemical demonstration of contractile proteins in astrocytes, marginal glial and ependymal cells in rat diencephalon. Cell Tissue Res 180:133–137
Haug H (1971) Die Membrana limitans gliae superficialis der Sehrinde der Katze. Z Zellforsch 115:79–87
Haug H (1972) Die postnatale Entwicklung der Gliadeckschicht der Sehrinde der Katze. Eine elektronenmikroskopische Studie über die Ausbildung von Lamellenstapeln. Z Zellforsch 123:544–565
Lehrer SS (1981) Damage to actin filaments by glutaraldehyde: protection by tropomyosin. J Cell Biol 90:459–466
Lenard J, Singer SJ (1968) Alteration of the conformation of proteins in red blood cell membranes and in solution by fixatives used in electron microscopy. J Cell Biol 37:117–121
Lenhossék M von (1891) Zur Kenntnis der Neuroglia des menschlichen Rückenmarkes. Verhandl Anat Gesellsch 5:193–221
Lenhossék M von (1885) Der feinere Bau des Nervensystems im Lichte neuesten Forschungen. Fischer's Medicin, Buchhandlung H Kornfeld, Berlin, pp 176–247
Maupin-Szamier P, Pollard TD (1978) Actin filament destruction by osmium tetroxide. J Cell Biol 77:837–852
Mesland DAM, Spiele H, Roos E (1981) Membrane-associated cytoskeleton and coated vesicles in cultured hepatocytes visualized by dry-cleaving. Exp Cell Res 132:169–184
Mori S, Leblond CP (1969) Electron microscopic features and proliferation of astrocytes in the corpus callosum of the rat. J Comp Neurol 137:197–226
Peters K-R, Carley WW, Palade GE (1985) Endothelial plasmalemmal vesicles have a characteristic striped bipolar surface structure. J Cell Biol 101:2233–2238
Tsukita S, Ishikawa H, Kurokawa M (1981) Isolation of 10-nm filaments from astrocytes in the mouse optic nerve. J Cell Biol 88:245–250
Vacquier VD (1975) The isolation of intact cortical granules from sea urchin eggs: calcium oons trigger granule discharge. Dev Biol 43:62–74
Williams V (1975) Intercellular relationships in the external glial limiting membrane of the neocortex of the cat and rat. Am J Anat 144:421–432
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Sasaki, H. Subpial glial limiting membrane of the cat spinal cord visualized by scanning electron microscopy. Anat Embryol 179, 533–540 (1989). https://doi.org/10.1007/BF00315696
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DOI: https://doi.org/10.1007/BF00315696