Alterations of Hippocampal Myelin Sheath and Axon Sprouting by Status Convulsion and Regulating Lingo-1 Expression with RNA Interference in Immature and Adult Rats

2018 ◽  
Vol 43 (3) ◽  
pp. 721-735 ◽  
Author(s):  
Xiao-Jie Song ◽  
Wei Han ◽  
Rong He ◽  
Tian-Yi Li ◽  
Ling-Ling Xie ◽  
...  
Keyword(s):  
Rna Interference ◽  
Myelin Sheath ◽  
Adult Rats ◽  
Axon Sprouting

scholarly journals Reproducibility in Nerve Morphometry: Comparison between Methods and among Observers

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Antônio Paulo da Costa Bilego Neto ◽  
Fernando Braga Cassiano Silveira ◽  
Greice Anne Rodrigues da Silva ◽  
Luciana Sayuri Sanada ◽  
Valéria Paula Sassoli Fazan
Keyword(s):  
Myelin Sheath ◽  
Computer Software ◽  
Myelinated Fiber ◽  
Adult Rats ◽  
Single Experiment ◽  
Myelinated Fibers ◽  
Manual Intervention ◽  
Reproducible Method ◽  
Semiautomated Method ◽  
Nerve Morphometry

We investigated the reproducibility of a semiautomated method (computerized with manual intervention) for nerve morphometry (counting and measuring myelinated fibers) between three observers with different levels of expertise and experience with the method. Comparisons between automatic (fully computerized) and semiautomated morphometric methods performed by the same computer software using the same nerve images were also performed. Sural nerves of normal adult rats were used. Automatic and semiautomated morphometry of the myelinated fibers were made through the computer software KS-400. Semiautomated morphometry was conducted by three independent observers on the same images, using the semiautomated method. Automatic morphometry overestimated the myelin sheath area, thus overestimating the myelinated fiber size and underestimating the axon size. Fiber distributions overestimation was of 0.5 μm. For the semiautomated morphometry, no differences were found between observers for myelinated fiber and axon size distributions. Overestimation of the myelin sheath size of normal fibers by the fully automatic method might have an impact when morphometry is used for diagnostic purposes. We suggest that not only semiautomated morphometry results can be compared between different centers in clinical trials but it can also be performed by more than one investigator in one single experiment, being a reliable and reproducible method.

scholarly journals Estrogen Elicits Dorsal Root Ganglion Axon Sprouting via a Renin-Angiotensin System

Endocrinology ◽  
2008 ◽  
Vol 149 (7) ◽  
pp. 3452-3460 ◽  
Author(s):  
Anuradha Chakrabarty ◽  
Audrey Blacklock ◽  
Stanislav Svojanovsky ◽  
Peter G. Smith
Keyword(s):  
Estrogen Receptor ◽  
Dorsal Root Ganglion ◽  
Dorsal Root ◽  
Drg Neurons ◽  
Predisposing Factor ◽  
Adult Rats ◽  
Axon Sprouting ◽  
Pain Syndromes

Many painful conditions occur more frequently in women, and estrogen is a predisposing factor. Estrogen may contribute to some pain syndromes by enhancing axon outgrowth by sensory dorsal root ganglion (DRG) neurons. The objective of the present study was to define mechanisms by which estrogen elicits axon sprouting. The estrogen receptor-α agonist propyl pyrazole triol induced neurite outgrowth from cultured neonatal DRG neurons, whereas the estrogen receptor-β agonist diarylpropionitrile was ineffective. 17β-Estradiol (E2) elicited sprouting from peripherin-positive unmyelinated neurons, but not larger NF200-positive myelinated neurons. Microarray analysis showed that E2 up-regulates angiotensin II (ANGII) receptor type 2 (AT2) mRNA in vitro, and studies in adult rats confirmed increased DRG mRNA and protein in vivo. AT2 plays a central role in E2-induced axon sprouting because AT2 blockade by PD123,319 eliminated estrogen-mediated sprouting in vitro. We assessed whether AT2 may be responding to locally synthesized ANGII. DRG from adult rats expressed mRNA for renin, angiotensinogen, and angiotensin converting enzyme (ACE), and protein products were present and occasionally colocalized within neurons and other DRG cells. We determined if locally synthesized ANGII plays a role in estrogen-mediated sprouting by blocking its formation using the ACE inhibitor enalapril. ACE inhibition prevented estrogen-induced neuritogenesis. These findings support the hypothesis that estrogen promotes DRG nociceptor axon sprouting by up-regulating the AT2 receptor, and that locally synthesized ANGII can induce axon formation. Therefore, estrogen may contribute to some pain syndromes by enhancing the pro-neuritogenic effects of AT2 activation by ANGII.

Further Studies on the Ultrastructure of Harderian Gland in Adult Rats

1974 ◽  
Vol 32 ◽  
pp. 288-289
Author(s):  
Alfredo Feria-Velasco ◽  
Guadalupe Tapia-Arizmendi
Keyword(s):  
Fine Structure ◽  
Domestic Fowl ◽  
Animal Species ◽  
Acinar Cells ◽  
Harderian Gland ◽  
Myoepithelial Cells ◽  
The Other ◽  
Albino Rats ◽  
Adult Rats ◽  
Cell Components

The fine structure of the Harderian gland has been described in some animal species (hamster, rabbit, mouse, domestic fowl and albino rats). There are only two reports in the literature dealing on the ultrastructure of rat Harderian gland in adult animals. In one of them the author describes the myoepithelial cells in methacrylate-embbeded tissue, and the other deals with the maturation of the acinar cells and the formation of the secretory droplets. The aim of the present work is to analize the relationships among the acinar cell components and to describe the two types of cells located at the perifery of the acini.

Triple Fixation For Electron Microscopy

1968 ◽  
Vol 26 ◽  
pp. 90-91 ◽  
Author(s):  
M. A. Hayat
Keyword(s):  
Electron Microscopy ◽  
Endoplasmic Reticulum ◽  
Electron Beam ◽  
Plasma Membrane ◽  
Myelin Sheath ◽  
Good Deal ◽  
Granular Structure ◽  
Oxidizing Agent ◽  
Fixation Technique ◽  
Large Clusters

Potassium permanganate has been successfully employed to study membranous structures such as endoplasmic reticulum, Golgi, plastids, plasma membrane and myelin sheath. Since KMnO4 is a strong oxidizing agent, deposition of manganese or its oxides account for some of the observed contrast in the lipoprotein membranes, but a good deal of it is due to the removal of background proteins either by dehydration agents or by volatalization under the electron beam. Tissues fixed with KMnO4 exhibit somewhat granular structure because of the deposition of large clusters of stain molecules. The gross arrangement of membranes can also be modified. Since the aim of a good fixation technique is to preserve satisfactorily the cell as a whole and not the best preservation of only a small part of it, a combination of a mixture of glutaraldehyde and acrolein to obtain general preservation and KMnO4 to enhance contrast was employed to fix plant embryos, green algae and fungi.

Biodegradable polyester neuroprostheses promote the reconnection of separated peripheral nerve stubs

1992 ◽  
Vol 50 (2) ◽  
pp. 1094-1095
Author(s):  
Beverly L. Giammara ◽  
Jennifer S. Stevenson ◽  
Peggy E. Yates ◽  
Robert H. Gunderson ◽  
Jacob S. Hanker
Keyword(s):  
Image Analysis ◽  
Basement Membrane ◽  
Periodic Acid ◽  
Light And Electron Microscopy ◽  
Computer Assisted ◽  
Type Iii Collagen ◽  
Image Analysis System ◽  
Biodegradable Polyester ◽  
Adult Rats ◽  
Type Iv

An 11mm length of sciatic nerve was removed from 10 anesthetized adult rats and replaced by a biodegradable polyester Vicryl™ mesh sleeve which was then injected with the basement membrane gel, Matrigel™. It was noted that leg sensation and movement were much improved after 30 to 45 days and upon sacrifice nerve reconnection was noted in all animals. Epoxy sections of the repaired nerves were compared with those of the excised segments by the use of a variation of the PAS reaction, the PATS reaction, developed in our laboratories for light and electron microscopy. This microwave-accelerated technique employs periodic acid, thiocarbohydrazide and silver methenamine. It stains basement membrane or Type IV collagen brown and type III collagen (reticulin), axons, Schwann cells, endoneurium and perineurium black. Epoxy sections of repaired and excised nerves were also compared by toluidine blue (tb) staining. Comparison of the sections of control and repaired nerves was done by computer-assisted microscopic image analysis using an Olympus CUE-2 Image Analysis System.

High-voltage EM description of the types and distribution of sensory endings in the inner conical body of the rat vibrissal follicle-sinus complex

1990 ◽  
Vol 48 (3) ◽  
pp. 410-411
Author(s):  
Tony M. Mosconi ◽  
Min J. Song ◽  
Frank L. Rice
Keyword(s):  
Mammalian Species ◽  
Dorsal Side ◽  
Hair Shaft ◽  
Sensory Innervation ◽  
Conical Body ◽  
Adult Rats ◽  
Perpendicular Plane ◽  
Ultrastructural Studies ◽  
Unmyelinated Axons ◽  
Sensory Endings

Whiskers or vibrissal follicle-sinus complexes (F-SCs) on the snouts of many mammalian species are structures that have complex, dense sensory innervation. The innervation of F-SCs is remarkably similar in all species with the exception of one site - the inner conical body (ICB). The ICB is an elongated cylindrical structure that encircles the hair shaft near the neck of the follicle. This site has received only cursory attention in ultrastructural studies of the F-SCAdult rats were perfused after the method of Renehan and Munger2. F-SCs were quartered longitudinally and embedded separately in Epon-Araldite. Serial 0.25 μm sections were cut in either the longitudinal or perpendicular plane through the ICB and examined with an AEI EM7 1.2 MV HVEM (Albany, NY) at 1000 KV. Sensory endings were reconstructed from serial micrographs through at least 20 μm in the longitudinal plane and through 10 μm in the perpendicular plane.From two to six small superficial vibrissal nerves converge upon the neck of the F-SC and descend into the ICB. The nerves branch into smaller bundles of myelinated and unmyelinated axons along the dorsal side of the hair shaft.

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