Axonal regeneration in dorsal spinal roots is accelerated by peripheral axonal transection

1987 ◽  
Vol 411 (2) ◽  
pp. 406-408 ◽  
Author(s):  
P.M. Richardson ◽  
V.M.K. Verge
Keyword(s):  
Axonal Regeneration ◽  
Spinal Roots ◽  
Axonal Transection ◽  
Dorsal Spinal

scholarly journals Apolipoprotein E Affects In Vitro Axonal Growth and Regeneration via the MAPK Signaling Pathway

2018 ◽  
Vol 28 (6) ◽  
pp. 691-703 ◽  
Author(s):  
Cheng Yin ◽  
Zong-duo Guo ◽  
Zong-ze He ◽  
Zhen-yu Wang ◽  
Xiao-chuan Sun
Keyword(s):  
Apolipoprotein E ◽  
Signaling Pathway ◽  
Axonal Regeneration ◽  
Axonal Growth ◽  
Mapk Signaling ◽  
Mapk Signaling Pathway ◽  
Axonal Transection ◽  
Apoe Mrna ◽  
P38 Pathway

Following central nervous system injury in mammals, failed axonal regeneration is closely related to dysneuria. Previous studies have shown that the obvious effects of apolipoprotein E (ApoE) on traumatic brain injury (TBI) were associated with an axonal mechanism. However, little information on the actions of ApoE and its isoforms on axonal regeneration following TBI was provided. In our study, the cerebral cortices of ApoE-deficient (ApoE-/-) and wild-type (ApoE+/+) mice were cultured in vitro, and an axonal transection model was established. Interventions included the conditioned medium of astrocytes, human recombinant ApoE2/3/4 isoforms and inhibitors of the JNK/ERK/p38 pathway. Axonal growth and regeneration were evaluated by measuring the maximum distance and area of the axons. The expression levels of β-tubulin III, MAP2, ApoE, p-JNK, p-ERK and p-p38 were detected by immunofluorescence and western blotting. The results showed that ApoE mRNA and protein were expressed in intact axons and regenerated axons. Axonal growth and regeneration were attenuated in ApoE-/- mice but recovered by exogenous ApoE. Human recombinant ApoE3 positively influenced axonal growth and regeneration; these effects were mediated by the JNK/ERK/p38 pathway. These results suggest ApoE and its isoforms may have influenced axonal growth and regeneration via the MAPK signaling pathway in vitro.

scholarly journals Herophilus, Erasistratus, Aretaeus, and Galen: ancient roots of the Bell–Magendie Law

2007 ◽  
Vol 23 (1) ◽  
pp. 1-3 ◽  
Author(s):  
Matthew I. Tomey ◽  
Ricardo J. Komotar ◽  
J Mocco
Keyword(s):  
Motor Control ◽  
19Th Century ◽  
Neural Pathways ◽  
Early 19Th Century ◽  
Spinal Roots ◽  
Dorsal Spinal

✓Since the early 19th century, significant controversy has persisted over the competing claims of two men, Charles Bell and François Magendie, to a pivotal discovery: that the dorsal spinal roots subserve sensation, whereas the ventral spinal roots subserve motion. However, the foundations of neuroanatomy on which Bell and Magendie built their research was formed two millennia in advance. Exploration of the work of four ancient scholars—Herophilus, Erasistratus, Aretaeus, and Galen–reveals a remarkable early appreciation of the separate neural pathways (if not the correct physiology) responsible for sensory and motor control.

Nerve fibres with myelinated and unmyelinated portions in dorsal spinal roots

1988 ◽  
Vol 17 (5) ◽  
pp. 693-700 ◽  
Author(s):  
E. Pannese ◽  
M. Ledda ◽  
S. Matsuda
Keyword(s):  
Nerve Fibres ◽  
Spinal Roots ◽  
Dorsal Spinal

Electrophysiological Assessment of Spinal Circuits in Spasticity by Direct Dorsal Root Stimulation

Neurosurgery ◽  
1979 ◽  
Vol 4 (2) ◽  
pp. 146-151 ◽  
Author(s):  
Victor Aldo Fasano ◽  
Giancarlo Barolat-Romana ◽  
Sergio Zeme ◽  
Angelo Sguazzi
Keyword(s):  
Spinal Cord ◽  
Muscle Tone ◽  
Basic Mechanism ◽  
Common Finding ◽  
Inhibitory Processes ◽  
Positive Effects ◽  
Dorsal Roots ◽  
Spinal Roots ◽  
Dorsal Spinal ◽  
Stimulation Of

Abstract Experimental researchers have shown that, because of normal inhibitory processes, repetitive orthodromic stimulation of the dorsal spinal roots induces a depression of the reflex discharge in the spinal motoneurons that is a function of the stimulation rate. Because a lack of inhibitory processes is considered to be the basic mechanism of spasticity, intraoperative stimulation of dorsal spinal roots from L-1 to S-1 bilaterally was performed in 80 patients affected by cerebral palsy. In these patients spasticity (exaggerated stretch reflexes, marked increase of proprioceptive reflexes, and clonus) was the main symptom. We stimulated the dorsal roots adjacent to the spinal cord and recorded motor responses by electromyogram (EMG) in the corresponding muscle groups. The most important findings were that: (a) variable inhibition (diminished, increased, or normal) was encountered in the spinal circuits of the spastic patient; and (b) the individual roots and rootlets can have different effects upon segmentary output. The absence of normal inhibitory processes was the most common finding; surgical sectioning of the corresponding roots resulted in immediate reduction in muscle tone in the related muscles. Selecting the dorsal roots for section results in a remarkable reduction of negative side effects that may follow total or random rhizotomy (marked hypotonia, ataxia, sensory defects) and of the percentage of late recurrences. This procedure results in additional positive effects at segmentary and suprasegmentary levels. These results confirm the idea that the basic mechanism of spasticity is a central defect in the traffic regulation of peripheral afferents as they are transmitted to the spinal cord. This defect causes segmentary and suprasegmentary adaptive reactions that extend the negative outcome of the local increase of muscle tone.

Spinal nerve distributions in the upper Limb: The organization of the dermatome and afferent myotome

1981 ◽  
Vol 293 (1070) ◽  
pp. 509-554 ◽  
Keyword(s):  
Upper Limb ◽  
Receptive Fields ◽  
Spinal Nerve ◽  
Nerve Injuries ◽  
Spinal Nerves ◽  
Axial Muscles ◽  
Spinal Roots ◽  
Single Fibres ◽  
Dorsal Spinal ◽  
Afferent Innervation

Single fibres were dissected from the dorsal spinal roots of the nerves serving the brachial plexus in African green monkeys. The dermatomal organization of these spinal nerves was deduced from data concerning the receptive fields of 2834 single afferent fibres. These data were collected in an attempt to reconcile some of the discrepancies that exist in published descriptions of the dermatomes in primates; our results and the literature reviewed suggest that the cutaneous region served by one spinal nerve is actually much wider and much more variable in location than is generally recognized. This makes any summary diagram a misleading indicator of the true complexity of the spinal innervation of the upper limb. In spite of this variability among individuals, within any specific individual there is a regular and orderly progression of innervation which allows prediction of the region served by a particular spinal nerve when information concerning the site of innervation of adjacent nerves is available. The territory of each myotome tended to be larger than the dermatome of the same spinal nerve. Most muscles of the limb received afferent innervation from three to four different spinal nerves. Further, the territory of the myotome did not of necessity coincide with the dermatome of the same spinal nerve. Even those nerves innervating the hand still innervated axial muscles. These observations have important implications for the diagnosis of spinal nerve injuries.

A voltage- and time-dependent rectification in rat dorsal spinal root axons

1991 ◽  
Vol 66 (3) ◽  
pp. 719-728 ◽  
Author(s):  
B. D. Birch ◽  
J. D. Kocsis ◽  
F. Di Gregorio ◽  
R. B. Bhisitkul ◽  
S. G. Waxman
Keyword(s):  
Membrane Potential ◽  
Time Dependent ◽  
Decay Phase ◽  
Resting Potential ◽  
Inward Rectification ◽  
Voltage Dependent ◽  
Spinal Roots ◽  
Sucrose Gap ◽  
Conductance Increase ◽  
Dorsal Spinal

1. Rat dorsal spinal roots were studied by the use of whole-nerve sucrose gap and intra-axonal recording techniques. A prominent time-dependent conductance increase as evidenced by a relaxation or "sag" in membrane potential toward resting potential was elicited in dorsal spinal roots by constant hyperpolarizing current pulses. The relaxation, or sag, indicative of inward rectification, reached a maximal level and then decayed during the current pulse. 2. The time-dependent sag elicited by hyperpolarization was reduced when Na+ or K+ was removed from the normal bath solution but was abolished with the removal of both Na+ and K+. Tetrodotoxin (TTX), tetraethylammonium (TEA), and 4-aminopyridine (4-AP) did not affect the depolarization sag, suggesting that conventional voltage-dependent sodium and potassium channels do not underlie the inward rectification. 3. Cs+ in low concentrations completely abolished the inward rectification, whereas Ba2+ induced a partial block. 4. Current-voltage curves indicate that the magnitude of the depolarizing sag increases monotonically with increasing hyperpolarization. The time required to reach peak hyperpolarization, maximal sag potential, and the time between peak hyperpolarization and sag membrane potentials decreases with increasing levels of hyperpolarization. 5. The inward rectification is refractory to further stimulation during its decay phase, as revealed by paired-pulse protocols. This decay in inward rectification is both time and voltage dependent and is observed on a single axon level by the use of intra-axonal recording techniques as well as from whole-root recordings in the sucrose gap. 6. It is concluded that rat dorsal root fibers display a prominent time-dependent conductance increase in response to hyperpolarization that depends on both Na+ and K+ permeability and is blocked by Cs+. This rectification displays a decay phase that has not been previously described for similar conductances. It is argued that the Na+ component of this conductance is primarily responsible for stabilizing membrane potential near resting potential during periods of hyperpolarization.

Differences between mammalian ventral and dorsal spinal roots in response to blockade of potassium channels during maturation

1985 ◽  
Vol 224 (1236) ◽  
pp. 355-366 ◽  
Keyword(s):  
Potassium Channels ◽  
Action Potential ◽  
Functional Organization ◽  
Potassium Conductance ◽  
Compound Action Potential ◽  
Developmental Differences ◽  
Differential Sensitivity ◽  
Spinal Roots ◽  
The Individual ◽  
Dorsal Spinal

Differences in potassium channel organization between motor and sensory fibres have been described in amphibians but have not previously been examined in mammals. In the present investigation, we studied whole nerve and single axon responses following pharmacological blockade of potassium conductance in rat ventral and dorsal spinal roots during maturation. Our results indicate a differential sensitivity in maturing mammalian motor and sensory fibres which is most apparent in younger roots. Specifically, application of 4-aminopyridine (4-AP) results in a broadening of the compound action potential in ventral roots which is associated with a delayed repolarization of the individual action potential of single fibres. In contrast, blockade of potassium channels in young dorsal roots results in a late negativity in the compound response which is correlated with multispike bursting activity recorded from single sensory fibres. The effects of 4-AP on ventral root fibres diminish earlier in the course of maturation than do the effects of 4-AP in dorsal root fibres. These results demonstrate developmental differences in the functional organization of potassium channels in mammalian motor and sensory axons which may have implications for differences in coding properties between these two classes of axons.

Effect of ether anesthesia on 17-hydroxycorticosteroid secretion in dogs

1959 ◽  
Vol 197 (6) ◽  
pp. 1261-1262 ◽  
Author(s):  
Tatuzi Suzuki ◽  
Kazukuni Yamashita ◽  
Takaaki Mitamura
Keyword(s):  
Venous Blood ◽  
Secretion Rate ◽  
Ether Anesthesia ◽  
Spinal Roots ◽  
The Mean ◽  
Dorsal Spinal

In dogs with previously cut dorsal spinal roots (T11-L3), adrenal venous blood was collected without anesthetic or pain. Ether was then inhaled for 30–60 minutes. During and after ether inhalation, adrenal venous blood was again collected and the plasma was analyzed for 17-hydroxycorticosteroids (17-OHCS). The mean preinhalation control secretion rate of 17-OHCS by one adrenal was 0.10 (0.06–0.20) µg/kg/min. During ether inhalation it increased to 0.34–1.2 µg/kg/min. Thirty to sixty minutes after the end of ether inhalation the secretion rate increased to a maximum of 0.79–1.8 µg/kg/min. and then decreased.

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