Characteristics of the myelin sheath membrane of the spiral ganglion cell and the cochlear nerve of guinea pig.
The membrane structures of the myelin sheath of guinea pig spiral ganglion cell and cochlear nerve were examined using freeze-fracturing, rapid freezing and freeze substitution, and deep-etching techniques. The intermediate dense lines of the myelin sheath were observed only in the outermost several layers using thin and thick (1 micron) section techniques. The spaces between the two adjacent major dense lines at any layer of myelin sheath were occupied by flocculent materials in the freeze-substituted specimen. Periods between the two adjacent major dense lines were 13.3 nm in conventional fixation and 11.7 nm in rapid freezing followed by freeze substitution, respectively. A freeze-fracturing study showed no differences in membrane structures at any layer of myelin sheath. Developed tight-junction strands were observed parallel to the long axis of the myelin sheath in the deep-etched specimen. These findings may show the characteristics of myelin sheath membrane in the spiral ganglion cell and cochlear nerve of the guinea pig.
Tatsuoka
H
H
Department of Anatomy, Chiba University School of Medicine, Japan.
Nagano
T
T
Chiba
T
T
D000818:Animals; D003056:Cochlear Nerve / Q000648:ultrastructure*; D006168:Guinea Pigs; D008854:Microscopy, Electron; D009186:Myelin Sheath / Q000648:ultrastructure*; D013136:Spiral Ganglion / Q000648:ultrastructure*