Characteristics of end-plates formed in mouse skeletal muscles reinnervated by their own or by foreign nerves

Guy Smith Bewick, D A Tonge

Research output: Contribution to journalArticle

9 Citations (Scopus)

Abstract

Morphological and electrophysiological techniques were used to study the neuromuscular junctions of soleus and extensor digitorum longus muscles in normal mice and 6 months after reinnervation by either their original or foreign nerves. In muscles reinnervated by foreign nerves, there were increased incidences of morphological abnormalities, including ultra-terminal axonal sprouting, multiaxonal innervation of end-plates, and ectopic synapse formation, as compared with both normal muscles and muscles reinnervated by their correct nerves. In spite of the morphological abnormalities, however, there was no evidence that the effectiveness of synapses (as estimated from the mean quantal content, m, of end-plate potentials) formed between nerves and inappropriate muscles was impaired. As had also been found in normally innervated muscles, the value of m was again higher in extensor digitorum longus than in soleus following reinnervation by inappropriate nerves. These results suggest that in mammals, when muscles are reinnervated by foreign nerves, mechanisms exist to maintain the efficacy of neuromuscular transmission, in contrast to the situation in amphibians (Sayers and Tonge, 1982: J. Physiol. (Lond.), 330:57-68). The abnormalities observed in this study following reinnervation may be a morphological manifestation of these corrective mechanisms.
Original languageEnglish
Pages (from-to)273-282
Number of pages10
JournalAnatomical Record, The, Part A: Discoveries in Molecular, Cellular, and Evolutionary Biology
Volume230
Issue number2
DOIs
Publication statusPublished - 1 Jun 1991

Fingerprint

skeletal muscle
nerve tissue
Skeletal Muscle
Muscles
muscles
mice
synapse
Synapses
Neuromuscular Junction
Excitatory Postsynaptic Potentials
Amphibians
innervation
sprouting
amphibians
Mammals
mammals
incidence
Incidence

Keywords

  • Animals
  • Electrophysiology
  • Locomotion
  • Mice
  • Motor Endplate
  • Muscle Denervation
  • Muscles
  • Nerve Regeneration
  • Synapses

Cite this

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title = "Characteristics of end-plates formed in mouse skeletal muscles reinnervated by their own or by foreign nerves",
abstract = "Morphological and electrophysiological techniques were used to study the neuromuscular junctions of soleus and extensor digitorum longus muscles in normal mice and 6 months after reinnervation by either their original or foreign nerves. In muscles reinnervated by foreign nerves, there were increased incidences of morphological abnormalities, including ultra-terminal axonal sprouting, multiaxonal innervation of end-plates, and ectopic synapse formation, as compared with both normal muscles and muscles reinnervated by their correct nerves. In spite of the morphological abnormalities, however, there was no evidence that the effectiveness of synapses (as estimated from the mean quantal content, m, of end-plate potentials) formed between nerves and inappropriate muscles was impaired. As had also been found in normally innervated muscles, the value of m was again higher in extensor digitorum longus than in soleus following reinnervation by inappropriate nerves. These results suggest that in mammals, when muscles are reinnervated by foreign nerves, mechanisms exist to maintain the efficacy of neuromuscular transmission, in contrast to the situation in amphibians (Sayers and Tonge, 1982: J. Physiol. (Lond.), 330:57-68). The abnormalities observed in this study following reinnervation may be a morphological manifestation of these corrective mechanisms.",
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T1 - Characteristics of end-plates formed in mouse skeletal muscles reinnervated by their own or by foreign nerves

AU - Bewick, Guy Smith

AU - Tonge, D A

PY - 1991/6/1

Y1 - 1991/6/1

N2 - Morphological and electrophysiological techniques were used to study the neuromuscular junctions of soleus and extensor digitorum longus muscles in normal mice and 6 months after reinnervation by either their original or foreign nerves. In muscles reinnervated by foreign nerves, there were increased incidences of morphological abnormalities, including ultra-terminal axonal sprouting, multiaxonal innervation of end-plates, and ectopic synapse formation, as compared with both normal muscles and muscles reinnervated by their correct nerves. In spite of the morphological abnormalities, however, there was no evidence that the effectiveness of synapses (as estimated from the mean quantal content, m, of end-plate potentials) formed between nerves and inappropriate muscles was impaired. As had also been found in normally innervated muscles, the value of m was again higher in extensor digitorum longus than in soleus following reinnervation by inappropriate nerves. These results suggest that in mammals, when muscles are reinnervated by foreign nerves, mechanisms exist to maintain the efficacy of neuromuscular transmission, in contrast to the situation in amphibians (Sayers and Tonge, 1982: J. Physiol. (Lond.), 330:57-68). The abnormalities observed in this study following reinnervation may be a morphological manifestation of these corrective mechanisms.

AB - Morphological and electrophysiological techniques were used to study the neuromuscular junctions of soleus and extensor digitorum longus muscles in normal mice and 6 months after reinnervation by either their original or foreign nerves. In muscles reinnervated by foreign nerves, there were increased incidences of morphological abnormalities, including ultra-terminal axonal sprouting, multiaxonal innervation of end-plates, and ectopic synapse formation, as compared with both normal muscles and muscles reinnervated by their correct nerves. In spite of the morphological abnormalities, however, there was no evidence that the effectiveness of synapses (as estimated from the mean quantal content, m, of end-plate potentials) formed between nerves and inappropriate muscles was impaired. As had also been found in normally innervated muscles, the value of m was again higher in extensor digitorum longus than in soleus following reinnervation by inappropriate nerves. These results suggest that in mammals, when muscles are reinnervated by foreign nerves, mechanisms exist to maintain the efficacy of neuromuscular transmission, in contrast to the situation in amphibians (Sayers and Tonge, 1982: J. Physiol. (Lond.), 330:57-68). The abnormalities observed in this study following reinnervation may be a morphological manifestation of these corrective mechanisms.

KW - Animals

KW - Electrophysiology

KW - Locomotion

KW - Mice

KW - Motor Endplate

KW - Muscle Denervation

KW - Muscles

KW - Nerve Regeneration

KW - Synapses

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M3 - Article

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