Effects of lanthanum and calcium on chronically denervated muscle fibers

Following damage to the peripheral nerve, the neuromuscular junction begins to degenerate, the muscle fibers become sensitive to acetylcholine over their entire length, the membrane electrical properties are altered and the muscle fibers become atrophic. It has been proposed that such anomalies might be due to inactivity, a lack of neurotrophic influence or a combination of both factors. The idea that In activity might be responsible for these changes has led to the use of electrotherapy to influence the healing process and promote nerve reinnervation. It has been recently suggested that electrical stimulation might be beneficial in preserving the neuromuscular junction in the denervated muscle. The present study was undertaken to determine morphologically the effect of electrical stimulation treatment on the endplates in denervated muscle.

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RE-INNERVATION OF DENERVATED MUSCLE FIBERS BY ADJACENT FUNCTIONING MOTOR UNITS

American Journal of Physiology-Legacy Content ◽

10.1152/ajplegacy.1945.144.4.477 ◽

1945 ◽

Vol 144 (4) ◽

pp. 477-493 ◽

Cited By ~ 49

Author(s):

A. Van Harreveld

Keyword(s):

Muscle Fibers ◽

Motor Units ◽

Denervated Muscle

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Severely atrophic human muscle fibers with nuclear misplacement survive many years of permanent denervation

European Journal of Translational Myology ◽

10.4081/ejtm.2016.5894 ◽

2016 ◽

Vol 26 (2) ◽

Cited By ~ 10

Author(s):

Ugo Carraro ◽

Helmut Kern

Keyword(s):

Muscle Fibers ◽

Human Muscle ◽

Slow Muscle ◽

Denervated Muscle ◽

Cord Injury ◽

Atrophic Muscle ◽

Complete Spinal Cord Injury ◽

Muscle Biopsies ◽

Immunohistochemical Analyses

Likewise in rodents, after complete spinal cord injury (SCI) the lower motor neuron (LMN) denervated human muscle fibers lose completely the myofibrillar apparatus and the coil distribution of myonuclei that are relocated in groups (nuclear clumps) in the center of severely atrophic muscle fibers. Up to two years of LMN denervation the muscle fibers with nuclear clumps are very seldom, but in this cohort of patients the severely atrophic muscle fibers are frequent in muscle biopsies harvested three to six years after SCI. Indeed, the percentage increased to 27 ± 9% (p< 0.001), and then abruptly decreased from the 6th year onward, when fibrosis takes over to neurogenic muscle atrophy. Immunohistochemical analyses shown that nuclear misplacements occurred in both fast and slow muscle fibers. In conclusion, human muscle fibers survive permanent denervation much longer than generally accepted and relocation of nuclei is a general behavior in long term denervated muscle fibers.

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Patterns of Motoneuron Dysfunction and Recovery

Canadian Journal of Neurological Sciences / Journal Canadien des Sciences Neurologiques ◽

10.1017/s0317167100019922 ◽

1975 ◽

Vol 2 (1) ◽

pp. 5-15 ◽

Cited By ~ 6

Author(s):

Alan McComas ◽

Adrian Upton ◽

Per Jorgensen

Keyword(s):

Muscle Fibers ◽

Motor Units ◽

Denervated Muscle ◽

Muscle Response ◽

Axonal Sprouts ◽

Electrophysiological Studies ◽

Synaptic Failure ◽

Rate Of Recovery ◽

Evoked Muscle Response ◽

Extensor Digitorum Brevis

SUMMARY:Electrophysiological studies have been carried out on five patients with neuropathies of different etiologies. In each patient serial estimates were made of the numbers of functioning motor units in various muscles. It was found that the intensity of the neuropathic process and the rate of recovery differed in a consistent way among the motoneuron pools investigated. The lesion was more severe in extensor digitorum brevis neurons than in thenar neurons, while the hypothenar ones were least affected. A stage of partial synaptic failure has been recognized in which a motoneuron appears to be no longer able to excite a muscle fiber, but still capable of maintaining certain trophic activities. By comparing the number of functioning motor units with the size of the maximum evoked muscle response it has been possible to detect the adoption of denervated muscle fibers by axonal sprouts from ‘healthy’ surviving neurons (collateral reinnervation). Lastly, in some muscles it appears that the adopted muscle fibers may subsequently be recaptured by the original motoneurons following recovery of the latter from the neurotoxic insult.

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