Alterations of diaphragm neuromuscular junctions with hypothyroidism

Y.s. Prakash, L. E. Gosselin, W. Z. Zhan, Gary C Sieck

Research output: Contribution to journalArticle

15 Citations (Scopus)

Abstract

Hypothyroidism (HYPO) often manifests as neuromuscular symptoms; however, little is known about its effects on the neuromuscular junction (NMJ). The present study examined changes in NMJ morphology and neuromuscular transmission failure (NTF) in the rat diaphragm muscle (Di(mus)) after 3 wk of HYPO. Three-color fluorescence immunocytochemistry and confocal microscopy were used to simultaneously visualize nerve terminals and axons, motor end plates, and myosin heavy chain isoform expression in Di(mus) fibers. NTF was assessed in vitro by comparing muscle fatigue induced by nerve with that induced by direct muscle stimulation. Diameters of axons innervating type I fibers were 30% smaller in the HYPO Di(mus) than in control (CTL). Planar areas of nerve terminals and end plates on type I and IIa fibers were 15-35% smaller in HYPO than in CTL. The extent of overlap between nerve terminals and end plates of type I fibers was 10% less in HYPO. Susceptibility to NTF during repetitive nerve stimulation was 20% greater in the CTL Di(mus) than in HYPO; however, changes in NMJ morphology could not fully account for the effect of HYPO on NTF.

Original languageEnglish (US)
Pages (from-to)1240-1248
Number of pages9
JournalJournal of Applied Physiology
Volume81
Issue number3
StatePublished - Sep 1996

Fingerprint

Neuromuscular Junction
Hypothyroidism
Diaphragm
Motor Endplate
Muscles
Muscle Fatigue
Myosin Heavy Chains
Presynaptic Terminals
Fluorescence Microscopy
Confocal Microscopy
Axons
Protein Isoforms
Color
Immunohistochemistry

Keywords

  • confocal microscopy
  • immunocytochemistry
  • myosin heavy chain
  • rat
  • thyroxine

ASJC Scopus subject areas

  • Physiology
  • Endocrinology
  • Orthopedics and Sports Medicine
  • Physical Therapy, Sports Therapy and Rehabilitation

Cite this

Prakash, Y. S., Gosselin, L. E., Zhan, W. Z., & Sieck, G. C. (1996). Alterations of diaphragm neuromuscular junctions with hypothyroidism. Journal of Applied Physiology, 81(3), 1240-1248.

Alterations of diaphragm neuromuscular junctions with hypothyroidism. / Prakash, Y.s.; Gosselin, L. E.; Zhan, W. Z.; Sieck, Gary C.

In: Journal of Applied Physiology, Vol. 81, No. 3, 09.1996, p. 1240-1248.

Research output: Contribution to journalArticle

Prakash, YS, Gosselin, LE, Zhan, WZ & Sieck, GC 1996, 'Alterations of diaphragm neuromuscular junctions with hypothyroidism', Journal of Applied Physiology, vol. 81, no. 3, pp. 1240-1248.
Prakash, Y.s. ; Gosselin, L. E. ; Zhan, W. Z. ; Sieck, Gary C. / Alterations of diaphragm neuromuscular junctions with hypothyroidism. In: Journal of Applied Physiology. 1996 ; Vol. 81, No. 3. pp. 1240-1248.
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