Microneurography: In Vivo Exploration of Impulse Traffic in Human Peripheral Nerve Fibers

1984 ◽  
pp. 19-28 ◽  
Author(s):  
Karl-Erik Hagbarth
Keyword(s):  
Peripheral Nerve ◽  
Nerve Fibers

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 EFFECTS OF THALLIUM SALTS ON NEURONAL MITOCHONDRIA IN ORGANOTYPIC CORD-GANGLIA-MUSCLE COMBINATION CULTURES

1973 ◽  
Vol 58 (1) ◽  
pp. 79-95 ◽  
Author(s):  
Peter S. Spencer ◽  
Edith R. Peterson ◽  
Ricardo Madrid A. ◽  
Cedric S. Raine
Keyword(s):  
Peripheral Nerve ◽  
Dorsal Root ◽  
Time Course ◽  
Nerve Fibers ◽  
Dorsal Root Ganglion Neurons ◽  
Matrix Space ◽  
Neurotoxic Effects ◽  
Ganglion Neurons

A functionally coupled organotypic complex of cultured dorsal root ganglia, spinal cord peripheral nerve, and muscle has been employed in an experimental approach to the investigation of the neurotoxic effects of thallium. Selected cultures, grown for up to 12 wk in vitro, were exposed to thallous salts for periods ranging up to 4 days. Cytopathic effects were first detected after 2 h of exposure with the appearance of considerably enlarged mitochondria in axons of peripheral nerve fibers. With time, the matrix space of these mitochondria became progressively swollen, transforming the organelle into an axonal vacuole bounded by the original outer mitochondrial membrane. Coalescence of adjacent axonal vacuoles produced massive internal axon compartments, the membranes of which were shown by electron microprobe mass spectrometry to have an affinity for thallium. Other axoplasmic components were displaced within a distended but intact axolemma. The resultant fiber swelling caused myelin retraction from nodes of Ranvier but no degeneration. Impulses could still propagate along the nerve fibers throughout the time course of the experiment. Comparable, but less severe changes were seen in dorsal root ganglion neurons and in central nerve fibers. Other cell types showed no mitochondrial change. It is uncertain how these findings relate to the neurotoxic effects of thallium in vivo, but a sensitivity of the nerve cell and especially its axon to thallous salts is indicated.

Application of Amniotic Extracellular Matrix Nerve Conduit with Biological Material in the Peripheral Nerve Defect In Vivo

2011 ◽  
Vol 322 ◽  
pp. 173-176
Author(s):  
Zhen Gao ◽  
Xiao Ting Luo ◽  
Nian Sheng Li ◽  
Wei Deng ◽  
Shu Mei Li
Keyword(s):  
Extracellular Matrix ◽  
Peripheral Nerve ◽  
Facial Nerve ◽  
Silica Gel ◽  
Peripheral Nerve Regeneration ◽  
Nerve Fibers ◽  
Neural Regeneration ◽  
Nerve Conduit ◽  
Time Points

Objective: To evaluate the peripheral nerve regeneration using a nerve conduit of amniotic extracellular matrix (AECM). Methods: 5 mm gap in the rabbit facial nerve was repaired with AECM conduit or with a silica gel conduit. After 7 days, 1 month and 3 months, the medullated nerve fibers and neural conductive velocity were determined. Results: On the 7th day, no neural regeneration was observed. But the neoformative neural fibers across AECM and silica gel were seen in the following 3 months, while the number and conductive velocity of medullated nerve fibers varied significantly at the different time points. Conclusion: AECM could repair the peripheral nerve defect.

scholarly journals Design and fabrication of a nerve-stretching device for in vivo mechanotransduction of peripheral nerve fibers

HardwareX ◽  
2020 ◽  
Vol 7 ◽  
pp. e00093
Author(s):  
Muhammad Sana Ullah Sahar ◽  
Matthew Barton ◽  
Geoffrey Tansley
Keyword(s):  
Peripheral Nerve ◽  
Nerve Fibers

Facilitated migration of cells from a transected peripheral nerve over collagen fibers: in vivo observations

1989 ◽  
Vol 47 ◽  
pp. 888-889
Author(s):  
Arthur J. Wasserman ◽  
Azam Rizvi ◽  
George Zazanis ◽  
Frederick H. Silver
Keyword(s):  
Sciatic Nerve ◽  
Peripheral Nerve ◽  
Collagen Gel ◽  
Collagen Fibers ◽  
Control Group ◽  
Guide Tube ◽  
Sprague Dawley ◽  
Silicone Tube ◽  
Thin Sections

In cases of peripheral nerve damage the gap between proximal and distal stumps can be closed by suturing the ends together, using a nerve graft, or by nerve tubulization. Suturing allows regeneration but does not prevent formation of painful neuromas which adhere to adjacent tissues. Autografts are not reported to be as good as tubulization and require a second surgical site with additional risks and complications. Tubulization involves implanting a nerve guide tube that will provide a stable environment for axon proliferation while simultaneously preventing formation of fibrous scar tissue. Supplementing tubes with a collagen gel or collagen plus extracellular matrix factors is reported to increase axon proliferation when compared to controls. But there is no information regarding the use of collagen fibers to guide nerve cell migration through a tube. This communication reports ultrastructural observations on rat sciatic nerve regeneration through a silicone nerve stent containing crosslinked collagen fibers.Collagen fibers were prepared as described previously. The fibers were threaded through a silicone tube to form a central plug. One cm segments of sciatic nerve were excised from Sprague Dawley rats. A control group of rats received a silicone tube implant without collagen while an experimental group received the silicone tube containing a collagen fiber plug. At 4 and 6 weeks postoperatively, the implants were removed and fixed in 2.5% glutaraldehyde buffered by 0.1 M cacodylate containing 1.5 mM CaCl2 and balanced by 0.1 M sucrose. The explants were post-fixed in 1% OSO4, block stained in 1% uranyl acetate, dehydrated and embedded in Epon. Axons were counted on montages prepared at a total magnification of 1700x. Montages were viewed through a dissecting microscope. Thin sections were sampled from the proximal, middle and distal regions of regenerating sciatic plugs.

scholarly journals Malignant Peripheral Nerve Sheath Tumor in the Nasal Cavity of a Neonate: A Case Report

2021 ◽  
pp. 014556132110141
Author(s):  
Xiufang Chi ◽  
Yue Wang ◽  
Haoming Yang ◽  
Cheng Xing ◽  
Jiamin Gan ◽  
...  
Keyword(s):  
Differential Diagnosis ◽  
Peripheral Nerve ◽  
Nasal Cavity ◽  
Nerve Fibers ◽  
Nerve Sheath Tumor ◽  
Rare Tumor ◽  
Nasal Mass ◽  
Peripheral Nerve Sheath Tumor ◽  
Related Literature ◽  
Nerve Sheath

Malignant peripheral nerve sheath tumor (MPNST) is a rare tumor that can develop on the lining of nerves and within the network of nerve fibers in different organs, and it is commonly found in the head and neck, limbs, and trunk. These tumors can occur in patients of any age. They most commonly occur in adults aged 20 to 50 years; however, fewer cases of this tumor in children have been reported. To date, no neonatal case of MPNST in the nasal cavity has been reported. Here, we report the case of a 4-day-old female newborn who presented with a nasal mass that re-enlarged after surgery and was diagnosed as MPNST of the nasal cavity on the basis of pathological results. This is the first report of MPNST in the nasal cavity of a neonate. Differential diagnosis and treatment of nasal masses have been proposed in the related literature.

Cellular mechanisms underlying cutaneous pressure-induced vasodilation: in vivo involvement of potassium channels

2005 ◽  
Vol 289 (1) ◽  
pp. H174-H180 ◽  
Author(s):  
Ambroise Garry ◽  
Dominique Sigaudo-Roussel ◽  
Sandra Merzeau ◽  
Odile Dumont ◽  
Jean Louis Saumet ◽  
...  
Keyword(s):  
Channel Blocker ◽  
Microvascular Dysfunction ◽  
Nerve Fibers ◽  
Cellular Mechanisms ◽  
Local Pressure ◽  
Cutaneous Vasodilation ◽  
Pressure Application ◽  
Iontophoretic Delivery ◽  
Small Conductance

In the skin of humans and rodents, local pressure induces localized cutaneous vasodilation, which may be protective against pressure-induced microvascular dysfunction and lesion formation. Once activated by the local pressure application, capsaicin-sensitive nerve fibers release neuropeptides that act on the endothelium to synthesize and release nitric oxide (NO) and prostaglandins, leading to the development of the cutaneous pressure-induced vasodilation (PIV). The present study was undertaken to test in vivo the hypothesis that PIV is mediated or modulated by differential activation of K+ channels in anesthetized rats using pharmacological methods. Local pressure was applied at 11.1 Pa/s. Endothelium-independent and -dependent vasodilation were tested using iontophoretic delivery of sodium nitroprusside (SNP) and acetylcholine (ACh), respectively, and was correlated with PIV response. PIV was reduced after systemic administration of tetraethylammonium (a nonspecific K+ channel blocker), iberiotoxin [a specific large-conductance Ca2+-activated K+ (BKCa) channel blocker], and glibenclamide [a specific ATP-sensitive K+ (KATP) channel blocker], whereas PIV was unchanged by apamin (a specific small-conductance Ca2+-activated K+channel blocker) and 4-aminopyridine (a specific voltage-sensitive K+ channel blocker). The responses to SNP and ACh were reduced by iberiotoxin but were unchanged by glibenclamide. We conclude that the cellular mechanism of PIV in skin involves BKCa and KATP channels. We suggest that the opening of BKCa and KATP channels contributes to the hyperpolarization of vascular smooth muscle cells to produce PIV development mainly via the NO and prostaglandin pathways, respectively.

Chitin conduits modified with DNA-peptide coating promote the peripheral nerve regeneration

2021 ◽  
Author(s):  
Songyang Liu ◽  
Liping Zhou ◽  
Ci Li ◽  
Tiantian Min ◽  
Changfeng Lu ◽  
...  
Keyword(s):  
Peripheral Nerve ◽  
Nerve Injury ◽  
Peripheral Nerve Injury ◽  
Amide Bond ◽  
Primary Amines ◽  
Direct Reaction ◽  
Ct Dna ◽  
Peptide Coating

Abstract Peripheral nerve injury (PNI) is one of the common clinical injuries which needs to be addressed. Previous studies demonstrated the effectiveness of using biodegradable chitin (CT) conduits small gap tubulization technology as a substitute for traditional epineurial neurorrhaphy. Aiming to improve the effectiveness of CT conduits in repairing PNI, we modified their surface with a DNA-peptide coating. The coating consisted of single strand DNA (ssDNA) and its complementary DNA’-peptide mimics. First, we immobilize ssDNA (DNA1+2) on CT conduits by EDC/NHS method to construct CT/DNA conduits. EDC/NHS was used to activate carboxyl groups of modified ssDNA for direct reaction with primary amines on the chitin via amide bond formation. Then, DNA1’-BDNF+DNA2’-VEGF mimic peptide （RGI+KLT）were bonded to CT/DNA conduits by complementary base pairing principle at room temperature to form CT/RGI+KLT conduits. When the surrounding environment rose to a certain point (37℃), the CT/RGI+KLT conduits achieved sustainable release of DNA’-peptide. In vitro, the CT conduits modified with the DNA-peptide coating promoted the proliferation and secretion of Schwann cells by maintaining their repair state. It also promoted the proliferation of HUVECs and axon outgrowth of DRG explants. In vivo, CT/RGI+KLT conduits promoted regeneration of injured nerves and functional recovery of target muscles, which was facilitated by the synergistic contribution of angiogenesis and neurogenesis. Our research brings DNA and DNA-peptide hybrids into the realm of tissue engineering to repair peripheral nerve injury.

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