scholarly journals Comparison of the fastest regenerating motor and sensory myelinated axons in the same peripheral nerve

Brain ◽  
2006 ◽  
Vol 129 (9) ◽  
pp. 2471-2483 ◽  
Author(s):  
M. Moldovan
Keyword(s):  
Peripheral Nerve ◽  
Myelinated Axons

Transplantation of Schwann cells in a collagen tube for the repair of large, segmental peripheral nerve defects in rats

2013 ◽  
Vol 119 (3) ◽  
pp. 720-732 ◽  
Author(s):  
Yerko A. Berrocal ◽  
Vania W. Almeida ◽  
Ranjan Gupta ◽  
Allan D. Levi
Keyword(s):  
Sciatic Nerve ◽  
Peripheral Nerve ◽  
Schwann Cells ◽  
Nerve Injury ◽  
Peripheral Nerve Injury ◽  
Fluorescent Protein ◽  
Control Groups ◽  
Myelinated Axons ◽  
Segmental Nerve ◽  
Green Fluorescent

Object Segmental nerve defects pose a daunting clinical challenge, as peripheral nerve injury studies have established that there is a critical nerve gap length for which the distance cannot be successfully bridged with current techniques. Construction of a neural prosthesis filled with Schwann cells (SCs) could provide an alternative treatment to successfully repair these long segmental gaps in the peripheral nervous system. The object of this study was to evaluate the ability of autologous SCs to increase the length at which segmental nerve defects can be bridged using a collagen tube. Methods The authors studied the use of absorbable collagen conduits in combination with autologous SCs (200,000 cells/μl) to promote axonal growth across a critical size defect (13 mm) in the sciatic nerve of male Fischer rats. Control groups were treated with serum only–filled conduits of reversed sciatic nerve autografts. Animals were assessed for survival of the transplanted SCs as well as the quantity of myelinated axons in the proximal, middle, and distal portions of the channel. Results Schwann cell survival was confirmed at 4 and 16 weeks postsurgery by the presence of prelabeled green fluorescent protein–positive SCs within the regenerated cable. The addition of SCs to the nerve guide significantly enhanced the regeneration of myelinated axons from the nerve stump into the proximal (p < 0.001) and middle points (p < 0.01) of the tube at 4 weeks. The regeneration of myelinated axons at 16 weeks was significantly enhanced throughout the entire length of the nerve guide (p < 0.001) as compared with their number in a serum–only filled tube and was similar in number compared with the reversed autograft. Autotomy scores were significantly lower in the animals whose sciatic nerve was repaired with a collagen conduit either without (p < 0.01) or with SCs (p < 0.001) when compared with a reversed autograft. Conclusions The technique of adding SCs to a guidance channel significantly enhanced the gap distance that can be repaired after peripheral nerve injury with long segmental defects and holds promise in humans. Most importantly, this study represents some of the first essential steps in bringing autologous SC-based therapies to the domain of peripheral nerve injuries with long segmental defects.

Acellular Nerve Allografts in Major Peripheral Nerve Repairs: An Analysis of Cases Presenting With Limited Recovery

Hand ◽  
2021 ◽  
pp. 155894472110031
Author(s):  
Blair R. Peters ◽  
Matthew D. Wood ◽  
Daniel A. Hunter ◽  
Susan E. Mackinnon
Keyword(s):  
Peripheral Nerve ◽  
Nerve Injury ◽  
Ulnar Nerve ◽  
Current Literature ◽  
Axonal Regeneration ◽  
Large Diameter ◽  
Nerve Injuries ◽  
Myelinated Axons ◽  
Acellular Nerve Allograft ◽  
Ulnar Nerve Injury

Background: Acellular nerve allografts have been used successfully and with increasing frequency to reconstruct nerve injuries. As their use has been expanded to treat longer gap, larger diameter nerve injuries, some failed cases have been reported. We present the histomorphometry of 5 such cases illustrating these limitations and review the current literature of acellular nerve allografts. Methods: Between 2014 and 2019, 5 patients with iatrogenic nerve injuries to the median or ulnar nerve reconstructed with an AxoGen AVANCE nerve allograft at an outside hospital were treated in our center with allograft excision and alternative reconstruction. These patients had no clinical or electrophysiological evidence of recovery, and allograft specimens at the time of surgery were sent for histomorphological examination. Results: Three patients with a median and 2 with ulnar nerve injury were included. Histology demonstrated myelinated axons present in all proximal native nerve specimens. In 2 cases, axons failed to regenerate into the allograft and in 3 cases, axonal regeneration diminished or terminated within the allograft. Conclusions: The reported cases demonstrate the importance of evaluating the length and the function of nerves undergoing acellular nerve allograft repair. In long length, large-diameter nerves, the use of acellular nerve allografts should be carefully considered.

Reoxygenation of anoxic peripheral nerve myelinated axons promotes re-establishment of normal elemental composition

1996 ◽  
Vol 715 (1-2) ◽  
pp. 189-196 ◽  
Author(s):  
Ellen J. Lehning ◽  
Peter K. Stys ◽  
Richard M.LoPachin
Keyword(s):  
Peripheral Nerve ◽  
Elemental Composition ◽  
Myelinated Axons

2,5-Hexanedione Alters Elemental Composition and Water Content of Rat Peripheral Nerve Myelinated Axons

2002 ◽  
Vol 63 (6) ◽  
pp. 2266-2278 ◽  
Author(s):  
Richard M. LoPachin ◽  
Ellen J. Lehning ◽  
Edward C. Stack ◽  
Steven J. Hussein ◽  
Albert J. Saubermann
Keyword(s):  
Peripheral Nerve ◽  
Water Content ◽  
Elemental Composition ◽  
Myelinated Axons ◽  
Rat Peripheral Nerve

Ganglioside Treatment Modifies Abnormal Elemental Composition in Peripheral Nerve Myelinated Axons of Experimentally Diabetic Rats

1993 ◽  
Vol 60 (2) ◽  
pp. 477-486 ◽  
Author(s):  
Richard M. LoPachin ◽  
Carolyn M. Castiglia ◽  
Albert J. Saubermann ◽  
Joseph Eichberg
Keyword(s):  
Peripheral Nerve ◽  
Elemental Composition ◽  
Diabetic Rats ◽  
Myelinated Axons

Extrasynaptic effects of GABA (γ-aminobutyric acid) agonists on myelinated axons of peripheral nerve

1994 ◽  
Vol 72 (4) ◽  
pp. 368-374 ◽  
Author(s):  
S. Liske ◽  
M. E. Morris
Keyword(s):  
Peripheral Nerve ◽  
Recovery Phase ◽  
Ventral Root ◽  
Aminobutyric Acid ◽  
Myelinated Axons ◽  
Bicuculline Methiodide ◽  
Proximal Site ◽  
Spinal Roots ◽  
Sciatic Nerves ◽  
Ventral Roots

Effects of the inhibitory neurotransmitter, GABA (γ-aminobutyric acid) on the excitability of myelinated fibers of isolated amphibian sciatic nerves and their dorsal and ventral spinal roots have been compared with those of a GABAA agonist, THIP (4,5,6,7-tetrahydroisoxazolo[5,4-c]pyridin-3-ol), and the GABAB agonist baclofen. Graded, prolonged increases in the amplitude of A-fiber half-maximal compound action potentials of Rana ballenderi sciatic nerves were evoked by GABA (Rmax = 49%, EC50 = 0.1 mM); responses to THIP were smaller (Rmax = 34%, EC50 = 1.1 mM) and with a different, distinctly biphasic recovery phase. In studies of Rana catesbeiana nerves and their attached spinal roots, excitability increases produced in fibers of the ventral roots by GABA were smaller than those of the dorsal roots. Peak changes evoked by THIP in both roots were similar to the effects of GABA on the ventral root; however, THIP's ventral root response showed much less sensitivity and was followed by a rapid recovery phase, undershoot, and secondary, prolonged enhancement. Bicuculline methiodide antagonized agonist-induced increases, and revealed the presence of significant decreases in excitability of the ventral root fibers at concentrations of GABA or THIP < 3 mM. Baclofen evoked inconsistent changes in the excitability of whole nerve and root fibers; small increases occurred with lower doses and secondary, delayed decreases with higher doses. The high concentration (≥ 0.1 mM) of the active isomer needed to cause a small response suggests a limited contribution and (or) presence of GABAB receptors. GABA and its agonists evoke complex, multiphasic excitability changes in the myelinated axons of the spinal roots and peripheral nerve. Contributions of different phases of increase and directions of change signify the participation of multiple receptors and (or) mechanisms. Responses of the dorsal root appear to reflect mainly GABAA-mediated increases in excitability; those of the ventral root include an additional or greater decrease, which may reflect a hyperpolarizing component mediated by a GABAC-like or bicuculline methiodide insensitive GABAA receptor. The large, prolonged responses of the sensory axons to GABA may be linked to their greater K+ channel conductance and related to the inhibitory transmitter's depolarizing action at the more proximal site of their central presynaptic terminals.Key words: dorsal and ventral roots, amphibian, excitability, GABAA, GABAB, GABAC.

Mechanisms of injury-induced calcium entry into peripheral nerve myelinated axons: in vitro anoxia and ouabain exposure

1995 ◽  
Vol 694 (1-2) ◽  
pp. 158-166 ◽  
Author(s):  
Ellen J. Lehning ◽  
Renu Doshi ◽  
Peter K. Stys ◽  
Richard M. LoPachin
Keyword(s):  
Peripheral Nerve ◽  
Calcium Entry ◽  
Myelinated Axons

scholarly journals THE ACTION POTENTIAL OF SPINAL AXONS IN VITRO

1954 ◽  
Vol 37 (4) ◽  
pp. 505-538 ◽  
Author(s):  
Donald O. Rudin ◽  
George Eisenman
Keyword(s):  
Action Potential ◽  
Peripheral Nerve ◽  
Time Course ◽  
Dorsal Column ◽  
Myelinated Axons ◽  
Spike Potential ◽  
Tissue Mass

Despite the trauma of dissection and special metabolic requirements, the physiological properties of funiculi of the mammalian spinal cord can be studied in vitro. They are adequately oxygenated by diffusion at 0.88 atm. pO2 and remain in a functionally normal state for over 12 hours. The internal consistency of several kinds of data presented in this and the foregoing papers (5, 38) serves to characterize certain properties of central myelinated axons whether excised or in situ. (1) Spinal tracts support a large spike potential in vitro whose form, duration, and velocity are comparable to those of alpha fibers in vitro and spinal tracts in vivo. (2) Properties consistent with a large L fraction are found in central axons whether excised or in situ. (3) Following conduction there has been identified post-spike supernormality with exponential time course (7.5 msecs. half-time) which is the result of activity intrinsic to parent fibers of dorsal columns. The supernormality is similar in form and magnitude both in excised and intact funiculi. (4) In excised funiculi the action potential of parent axons includes a large negative after-potential whose form and duration correspond satisfactorily with this supernormality. This potential appears not to result from activity arising in broken collaterals. (5) Central axons, excised or intact, fire spontaneously in the presence of citrate ion, and when synchronized by stimulation develop periodic oscillations at about 400 C.P.S. but show no such behavior in the presence of excess potassium ion. Certain characteristics peculiar to central axons indicate that they occupy an extreme position in the spectrum of properties encountered in conducting tissues. Dorsal column myelinated axons differ from their peripheral counterparts, even though they are parts of the same cell, in the following ways. The maintenance of the column spike potential is more critically dependent on CO2 and the entire tissue mass has a higher oxygen consumption. The negative after-potential is much larger and the positive after-potential, non-existent following a single volley, is more difficult to develop by repetitive stimulation. Unlike peripheral nerve, central axons are not incited to spontaneous activity by manipulation of certain constituents normally present in their environment. However, when induced by the application of citrate the resulting rhythmic behavior has twice the frequency of that in peripheral nerve. In general, the recovery process in central axons is more invariant than that in peripheral axons when they are subjected to similar changes in their artificial environments.

Mechanisms of Injury-Induced Calcium Entry into Peripheral Nerve Myelinated Axons: Role of Reverse Sodium-Calcium Exchange

2002 ◽  
Vol 66 (2) ◽  
pp. 493-500 ◽  
Author(s):  
Ellen J. Lehning ◽  
Renu Doshi ◽  
Norman Isaksson ◽  
Peter K. Stys ◽  
Richard M. LoPachin
Keyword(s):  
Peripheral Nerve ◽  
Calcium Entry ◽  
Myelinated Axons ◽  
Sodium Calcium ◽  
Calcium Exchange ◽  
Sodium Calcium Exchange
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