Changes of Thickness of Myelin Sheath and Structure Of Internodal Segments of Myelin Nerve Fibers of Sciatic Nerve of Rats in Ontogenesis

One of the unsolved issues in neuromorphology is the classification of myelin nerve fibers (MNF). Objective: to use cluster analysis to classify the sciatic nerve MNF. Material and methods. The work was performed using 5 one-year-old male Wistar rats. Semi-thin sections were stained with methylene blue. MNF morphometry was performed using ImageJ, and statistical processing – using the software environment R. Results of the study. Ward’s and k-means methods were used to cluster the MNF. Three clusters of MNFs are defined and their parameters are determined. The presented algorithm for adapting the literature data to the format of the obtained results includes determining the total average for the combined set of each indicator and the total variance, which is the sum of intragroup and intergroup variances. Conclusions: 1) for the classification of MNF it is advisable to use cluster analysis; 2) clustering should be performed according to the transsection areas of the axial cylinder and myelin sheath; 3) the number of clusters is determined by the agglomerative method of Ward, and their metrics – by the iterative method of k-means; 4) three clusters of MNF of the rat sciatic nerve differ in the transsection areas of the fibers, the axial cylinder and the myelin sheath and the percentage of nerve fibers; 5) when comparing identical indicators according to the obtained and literature data, the results were equivalent in the areas of the axial cylinder and myelin sheath and their shape coefficients, despite the fact that the classification of myelin fibers and their morphometry was performed using different methods.

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Adrenergic Nerve Fibers in the Human Fetal Sciatic Nerve

Cells Tissues Organs ◽

10.1159/000147084 ◽

1991 ◽

Vol 140 (4) ◽

pp. 369-372 ◽

Cited By ~ 4

Author(s):

J. Koistinaho

Keyword(s):

Sciatic Nerve ◽

Nerve Fibers ◽

Adrenergic Nerve

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NEUROPROTECTION OF ABELMOSCHUS ESCULENTUS L. AGAINST DIABETIC NEUROPATHY

Asian Journal of Pharmaceutical and Clinical Research ◽

10.22159/ajpcr.2018.v11s3.30023 ◽

2018 ◽

Vol 11 (15) ◽

pp. 28

Author(s):

Lee Wei Yang ◽

Santosh Fattepur ◽

Kiran Chanabasappa Nilugal ◽

Fadli Asmani ◽

Eddy Yusuf ◽

...

Keyword(s):

Body Weight ◽

Sciatic Nerve ◽

Diabetic Neuropathy ◽

Performance Test ◽

Neuroprotective Effect ◽

Thermal Hyperalgesia ◽

Diabetic Rats ◽

Nerve Fibers ◽

Abelmoschus Esculentus ◽

Rotarod Performance

Objective: The present study was designed to determine the neuroprotective effect of Abelmoschus esculentus L. on alloxan-induced diabetic neuropathy in rats.Methods: Diabetes was induced in rats with a single intraperitoneal injection of alloxan monohydrate (130 mg/kg b.w). The ethanol extract of A. esculentus L. at a dose of 100 and 200 mg/kg of body weight was administered at single dose per day to alloxan-induced diabetic rats for 21 days. The fasting blood glucose was screened in the intermittent on day 0, day 14, and day 21. Behavioral tests such as thermal hyperalgesia test and rotarod performance test were performed to assess the thermal sensitivity and muscle grip strength. At the end of the study period, experimental animals were sacrificed and sciatic nerve tissues were obtained for histopathological investigation.Results: Animals treated with A. esculentus L. extarct at a dose of 200 mg/kg of body weight significantly reduced (p<0.05) in hyperglycemia and thermal hyperalgesia and significantly increased (p<0.05) in rotarod performance. The sciatic nerve fiber of diabetic rats receiving 200 mg/kg of body weight of A. esculentus L. extract also shows no swelling of nerve fibers, and lesser demyelination was observed.Conclusion: These findings demonstrate that A. esculentus L. exhibits significant antidiabetic and neuroprotective effect against alloxan-induced diabetic neuropathy in rats.

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Amitriptyline Neurotoxicity

Anesthesiology ◽

10.1097/00000542-200406000-00026 ◽

2004 ◽

Vol 100 (6) ◽

pp. 1519-1525 ◽

Cited By ~ 41

Author(s):

Jean-Pierre Estebe ◽

Robert R. Myers

Keyword(s):

Nervous System ◽

Sciatic Nerve ◽

Local Anesthetic ◽

Dose Range ◽

Antidepressant Drug ◽

Nerve Fibers ◽

Anesthetic Agent ◽

Sprague Dawley ◽

Neurotoxic Effect ◽

Local Anesthetic Agent

Background Amitriptyline is a tricyclic antidepressant drug used systemically for the management of neuropathic pain. Antidepressants, as a class of drugs with direct neurologic actions, are becoming widely used for the management of chronic pain, although their mechanisms are not entirely understood. Amitriptyline exerts potent effects on reuptake of norepinephrine and serotonin and blocks alpha 2A adrenoreceptors and N-methyl-D-aspartate receptors. Because amitriptyline is also a particularly potent blocker of sodium channels and voltage-gated potassium and calcium channels, it has been recommended as a long-acting local anesthetic agent. Unfortunately, amitriptyline has significant toxic side effects in the central nervous system and cardiovascular system that are dose-related to its systemic administration. Therefore, before amitriptyline can be used clinically as a local anesthetic agent, it should be thoroughly explored with respect to its direct neurotoxic effect in the peripheral nervous system. Methods The left sciatic nerve of Sprague-Dawley rats (12/ group) received a single topical amitriptyline dose of 0.625, 1.25, 2.5, or 5 mg; a saline group (n = 2) was used as control. Neuropathologic evaluations were conducted in separate animals (n = 4) 1, 3, and 7 days later. Results Amitriptyline topically applied in vivo to rat sciatic nerve causes a dose-related neurotoxic effect. Drug doses of 0.625-5 mg all caused Wallerian degeneration of peripheral nerve fibers, with the number of affected fibers and the severity of the injury directly related to the dose. Conclusion Because the effective local anesthetic dose is within this dose range, the authors strongly recommend that amitriptyline not be used as a local anesthetic agent.

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Substance P-, CGRP- and NPY-immunoreactive nerve fibers in rat sciatic nerve-end neuromas

Regulatory Peptides ◽

10.1016/0167-0115(89)90244-9 ◽

1989 ◽

Vol 25 (1) ◽

pp. 11-24 ◽

Cited By ~ 24

Author(s):

K. Fried ◽

E. Brodin ◽

E. Theodorsson

Keyword(s):

Substance P ◽

Sciatic Nerve ◽

Nerve Fibers ◽

Rat Sciatic Nerve

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Biofabrication of nerve fibers with mimetic myelin sheath-like structure and aligned fibrous niche

Biofabrication ◽

10.1088/1758-5090/ab860d ◽

2020 ◽

Vol 12 (3) ◽

pp. 035013 ◽

Cited By ~ 2

Author(s):

Suping Chen ◽

Chengheng Wu ◽

Amin Liu ◽

Dan Wei ◽

Yun Xiao ◽

...

Keyword(s):

Myelin Sheath ◽

Nerve Fibers

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Electron Microscopy Analysis of Sciatic Nerve Fibers in C57BL/6 Transgenic Mice

Neurophysiology ◽

10.1007/s11062-020-09857-2 ◽

2020 ◽

Vol 52 (2) ◽

pp. 94-100

Author(s):

I. O. Govbakh ◽

O. M. Tsupykov ◽

E. G. Smozhanik ◽

V. V. Rubtsov ◽

M. Tymchyshin ◽

...

Keyword(s):

Electron Microscopy ◽

Sciatic Nerve ◽

Transgenic Mice ◽

Nerve Fibers ◽

Electron Microscopy Analysis ◽

Microscopy Analysis

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Computer Model for Action Potential Propagation Through Branch Point in Myelinated Nerves

Journal of Neurophysiology ◽

10.1152/jn.2001.85.1.197 ◽

2001 ◽

Vol 85 (1) ◽

pp. 197-210 ◽

Cited By ~ 49

Author(s):

Lei Zhou ◽

Shing Yan Chiu

Keyword(s):

Action Potential ◽

Branch Point ◽

Myelin Sheath ◽

Nerve Fibers ◽

Myelinated Nerve ◽

Axonal Membrane ◽

Pass Filter ◽

Low Pass Filter ◽

Action Potential Propagation ◽

Periaxonal Space

A mathematical model is developed for simulation of action potential propagation through a single branch point of a myelinated nerve fiber with a parent branch bifurcating into two identical daughter branches. This model is based on a previously published multi-layer compartmental model for single unbranched myelinated nerve fibers. Essential modifications were made to couple both daughter branches to the parent branch. There are two major features in this model. First, the model could incorporate detailed geometrical parameters for the myelin sheath and the axon, accomplished by dividing both structures into many segments. Second, each segment has two layers, the myelin sheath and the axonal membrane, allowing voltages of intra-axonal space and periaxonal space to be calculated separately. In this model, K ion concentration in the periaxonal space is dynamically linked to the activity of axonal fast K channels underneath the myelin in the paranodal region. Our model demonstrates that the branch point acts like a low-pass filter, blocking high-frequency transmission from the parent to the daughter branches. Theoretical analysis showed that the cutoff frequency for transmission through the branch point is determined by temperature, local K ion accumulation, width of the periaxonal space, and internodal lengths at the vicinity of the branch point. Our result is consistent with empirical findings of irregular spacing of nodes of Ranvier at axon abors, suggesting that branch points of myelinated axons play important roles in signal integration in an axonal tree.

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