Size-dependent distribution of axoplasm, schwann cell cytoplasm, and mitochondria in the peripheral nerve fibers of mouse

1968 ◽  
Vol 161 (3) ◽  
pp. 281-292 ◽  
Author(s):  
T. Samorajski ◽  
Reinhard L. Friede
Keyword(s):  
Schwann Cell ◽  
Peripheral Nerve ◽  
Nerve Fibers ◽  
Cell Cytoplasm ◽  
Size Dependent

scholarly journals A TIME-SEQUENCE AUTORADIOGRAPHIC STUDY OF THE IN VIVO INCORPORATION OF [1, 2-3H]CHOLESTEROL INTO PERIPHERAL NERVE MYELIN

1973 ◽  
Vol 58 (1) ◽  
pp. 42-53 ◽  
Author(s):  
Frank A. Rawlins
Keyword(s):  
Schwann Cell ◽  
Peripheral Nerve ◽  
Myelin Sheath ◽  
Central Zone ◽  
Autoradiographic Study ◽  
Nerve Fibers ◽  
Time Sequence ◽  
Time Interval ◽  
Electron Microscope Autoradiography

A time-sequence study of the incorporation and distribution of cholesterol in peripheral nerve myelin was carried out by electron microscope autoradiography. [1,2-3H]Cholesterol was injected into 10-day old mice and the sciatic nerves were dissected out at 10, 20, 40, 60, 90, 120, and 180 min after the injection. 20 min after injection the higher densities of grains due to the presence of [3H]cholesterol were confined to the outer and inner edges of the myelin sheath. Practically no cholesterol was detected in the midzone of the myelin sheath. 1 ½ h after injection, cholesterol showed a wider distribution within the myelin sheath, the higher densities of grains occurring over the two peripheral myelin bands, each approximately 3,100 Å wide. Cholesterol was also present in the center of the myelin sheath but to a considerably lesser extent. 3 h after injection cholesterol appeared homogeneously distributed within the myelin sheath. Schwann cell and axon compartments were also labeled at each time interval studied beginning 20 min postinjection. These observations indicate that preformed cholesterol enters myelin first and almost simultaneously through the inner and outer edges of the sheath; only after 90 min does the density of labeled cholesterol in the central zone of myelin reach the same density as that in the outer and inner zones. These findings suggest that cholesterol used by the nerve fibers in the formation and maintenance of the myelin sheath enters the lamellae from the Schwann cell cytoplasm and from the axon. The possibility of a bidirectional movement of molecules, i.e. from the Schwann cell to the axon and from the axon to the Schwann cell through the myelin sheath, is noted. The results are discussed in the light of recent observations on the exchange, reutilization, and transaxonal movement of cholesterol.

scholarly journals Nogo-C Inhibits Peripheral Nerve Regeneration by Regulating Schwann Cell Apoptosis and Dedifferentiation

2021 ◽  
Vol 14 ◽  
Author(s):  
Bo Jia ◽  
Wei Huang ◽  
Yu Wang ◽  
Peng Zhang ◽  
Zhiwei Wang ◽  
...  
Keyword(s):  
Sciatic Nerve ◽  
Schwann Cell ◽  
Peripheral Nerve ◽  
Nerve Regeneration ◽  
Schwann Cells ◽  
Nerve Injury ◽  
Cell Apoptosis ◽  
Peripheral Nerve Regeneration ◽  
Nerve Fibers ◽  
Cell Dedifferentiation

While Nogo protein demonstrably inhibits nerve regeneration in the central nervous system (CNS), its effect on Schwann cells in peripheral nerve repair and regeneration following sciatic nerve injury remains unknown. In this research, We assessed the post-injury expression of Nogo-C in an experimental mouse model of sciatic nerve-crush injury. Nogo-C knockout (Nogo-C–/–) mouse was generated to observe the effect of Nogo-C on sciatic nerve regeneration, Schwann cell apoptosis, and myelin disintegration after nerve injury, and the effects of Nogo-C on apoptosis and dedifferentiation of Schwann cells were observed in vitro. We found that the expression of Nogo-C protein at the distal end of the injured sciatic nerve increased in wild type (WT) mice. Compared with the injured WT mice, the proportion of neuronal apoptosis was significantly diminished and the myelin clearance rate was significantly elevated in injured Nogo-C–/– mice; the number of nerve fibers regenerated and the degree of myelination were significantly elevated in Nogo-C–/– mice on Day 14 after injury. In addition, the recovery of motor function was significantly accelerated in the injured Nogo-C–/– mice. The overexpression of Nogo-C in primary Schwann cells using adenovirus-mediated gene transfer promoted Schwann cells apoptosis. Nogo-C significantly reduced the ratio of c-Jun/krox-20 expression, indicating its inhibition of Schwann cell dedifferentiation. Above all, we hold the view that the expression of Nogo-C increases following peripheral nerve injury to promote Schwann cell apoptosis and inhibit Schwann cell dedifferentiation, thereby inhibiting peripheral nerve regeneration.

The Distribution of Electron-Dense Tracers in Peripheral Nerve Fibres

1971 ◽  
Vol 8 (2) ◽  
pp. 541-555
Author(s):  
SUSAN M. HALL ◽  
P. L. WILLIAMS
Keyword(s):  
Schwann Cell ◽  
Peripheral Nerve ◽  
Myelin Sheath ◽  
External Surface ◽  
Nerve Fibres ◽  
Cell Cytoplasm ◽  
Line Region ◽  
Periaxonal Space

Two electron-dense tracers, ferritin and lanthanum, have been administered to peripheral nerve fibres, and their uptake has been studied ultrastructurally. It was found that the perineurium was an effective barrier to ferritin in vivo, and the tracer was subsequently injected sub-perineurially. Ferritin uptake over a 120-min period was confined to occasional phagocytic vesicles in perineurial and Schwann cells, and to the nodal gap substance and paranodal periaxonal space. No uptake was observed in the myelin sheath, incisural intraperiod line gap, or in the axoplasm. Soaking fibres in ferritin in vitro resulted in a more generalized cytoplasmic and axoplasmic uptake, although the myelin sheath and Schmidt-Lanterman incisures remained devoid of the tracer. Lanthanum nitrate, included in the fixative solution, delineated the patent incisural intraperiod line gap, and outlined the external surface of the terminal loops of nodal Schwann cell cytoplasm, and the paranodal Schwann cell-axolemmal junction. Unlike ferritin, La3+ penetrated the myelin sheath, being usually confined to the intraperiod line region of the outer lamellae, where it was associated with a widening of the lamellar unit, and an apparent splitting of the intraperiod line. The results are discussed with regard to distribution of extracellular space in peripheral nerve fibres.

scholarly journals Incorporation of glycoproteins into peripheral nerve myelin.

1977 ◽  
Vol 75 (2) ◽  
pp. 326-338 ◽  
Author(s):  
R M Gould
Keyword(s):  
Schwann Cell ◽  
Peripheral Nerve ◽  
Gel Electrophoresis ◽  
Sodium Dodecyl ◽  
Temporal Distribution ◽  
Cell Cytoplasm ◽  
Rat Pups ◽  
Adult Mice ◽  
Formed Product ◽  
Silver Grains

Peripheral nerve myelin contains a dominant low molecular weight glycoprotein called Po. To study the metabolism of this glycoprotein, tritiated fucose was injected into the peripheral nerves of adult mice and developing rats, and the temporal distribution of label was examined by autoradiography and gel electrophoresis. Mice and rat pups, injected with fucose, were sacrificed from 1 h to 98 days later. Series of autoradiographs were prepared. At the shortest labeling periods, newly formed product was confined to juxtanuclear Schwann cell cytoplasm, in association with regions rich in Golgi apparatus. After longer labeling periods, silver grain levels in Schwann cell cytoplasm decreased; concomitantly, there was an increase of silver grains associated with myelin. In adult animals, label associated with myelin was concentrated over outer layers of thickly myelinated fibers. Even at the longest time intervals examined (72 and 98 days), this distribution of label was largely retained. In contrast, in developing animals, label became associated with inner layers of the thicker sheaths. At no time was label observed over axons. Gel electrophoresis revealed that tritiated fucose was a suitable precursor for the faster migrating peripheral nerve glycoprotein(s). At all times examined, there was a single major peak of radioactivity that co-migrated on sodium dodecyl sulfate (SDS) acrylamide gels with the Po protein. Sometimes, a faster migrating shoulder of radioactivity was noted. With increased labeling periods, there was an enrichment of radioactivity associated with Po, indicative of a relatively slow turnover rate.

scholarly journals THE ULTRASTRUCTURE OF ADULT VERTEBRATE PERIPHERAL MYELINATED NERVE FIBERS IN RELATION TO MYELINOGENESIS

1955 ◽  
Vol 1 (4) ◽  
pp. 271-278 ◽  
Author(s):  
J. David Robertson
Keyword(s):  
Electron Microscope ◽  
Schwann Cell ◽  
Cell Surface ◽  
Peripheral Nerve ◽  
Myelin Sheath ◽  
Nerve Fibers ◽  
Myelinated Nerve ◽  
Thin Sections ◽  
Double Membrane ◽  
Myelinated Nerve Fibers

Adult chameleon myelinated peripheral nerve fibers have been studied with the electron microscope in thin sections. The outer lamella of the myelin sheath has been found to be connected as a double membrane to the surface of the Schwann cell. The inner lamella is connected as a similar double membrane with the double axon-Schwann membrane. The relations of these double connecting membranes suggest that the layered myelin structure is composed of a double membrane which is closely wound about the axon as a helix. These findings support the new theory of myelinogenesis proposed recently by Geren. The possible significance of these results with respect to cell surface membranes and cytoplasmic double membranes is discussed.

scholarly journals Study of the Peripheral Nerve Fibers Myelin Structure Changes during Activation of Schwann Cell Acetylcholine Receptors

PLoS ONE ◽  
2016 ◽  
Vol 11 (7) ◽  
pp. e0158083 ◽  
Author(s):  
Ekaterina E. Verdiyan ◽  
Elvin S. Allakhverdiev ◽  
Georgy V. Maksimov
Keyword(s):  
Schwann Cell ◽  
Peripheral Nerve ◽  
Acetylcholine Receptors ◽  
Nerve Fibers ◽  
Myelin Structure ◽  
Structure Changes

scholarly journals Autophagy Is Involved in the Reduction of Myelinating Schwann Cell Cytoplasm during Myelin Maturation of the Peripheral Nerve

PLoS ONE ◽  
2015 ◽  
Vol 10 (1) ◽  
pp. e0116624 ◽  
Author(s):  
So Young Jang ◽  
Yoon Kyung Shin ◽  
So Young Park ◽  
Joo Youn Park ◽  
Seo-Hee Rha ◽  
...  
Keyword(s):  
Schwann Cell ◽  
Peripheral Nerve ◽  
Cell Cytoplasm ◽  
Myelinating Schwann Cell

scholarly journals Incorporation of newly formed lecithin into peripheral nerve myelin.

1976 ◽  
Vol 68 (3) ◽  
pp. 480-496 ◽  
Author(s):  
R M Gould ◽  
R M Dawson
Keyword(s):  
Sciatic Nerve ◽  
Schwann Cell ◽  
Peripheral Nerve ◽  
Intraperitoneal Injection ◽  
Axoplasmic Transport ◽  
Cell Cytoplasm ◽  
Neuronal Perikaryon ◽  
Myelin Sheaths ◽  
Adult Mice ◽  
Frog Sciatic Nerve

Radioactive choline was used to study the metabolism and movement of choline-containing phospholipids in peripheral nerve myelin of adult mice. Incorporation at various times after intraperitoneal injection was measured in serial segments of sciatic nerve as well as in myelin isolated from those segments. At no time (1 h to 35 days) could a proximal-distal difference in the extent of labeling be demonstrated. This finding suggests that incorporation of precursor choline phospholipids into nerve membranes is a local event, with little contribution from the neuronal perikaryon via axoplasmic transport. Autoradiographic investigations were undertaken to elucidate the pattern of movement of radioactive choline-labeled phospholipids, predominantly lecithin, into the myelin sheaths of the sciatic nerve. A sequence of autoradiographs was prepared from animals sacrificed between 20 min and 35 days after a microinjection of precursor directly into the nerve. Analysis of these autoradiograms revealed that labeling is initially concentrated in the Schwann cell cytoplasm. Later, the label moves first into the outer regions of the myelin sheaths and is eventually distributed evenly throughout the inner and outer layers of the sheath. At no time is there a build-up of label in the axon. The rate of uptake of precursor and subsequent redistribution of lecithin into the myelin were also examined in frog sciatic nerve (18 degrees C). Both uptake and redistribution processes were considerably slower in the cold-blooded animal.

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