A Parametric Study of the Neuromuscular Junction During Ontogenesis and Under Different External Conditions

Wernig, A.; Jans, H.; Zucker, Howard D.

doi:10.1007/978-1-4613-2307-5_26

Cited by 4 publications

(2 citation statements)

References 13 publications

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“…Since type I fibres are more frequently activated during motor behaviours (Burke, 1981;, a greater extent of overlap of pre-and postsynaptic elements of the NMJ may be an adaptive response for maintaining synaptic efficacy. Without particular reference to fibre type, previous studies have shown that there is a wide variability in NMJ morphology (Anzenbacher & Zenker, 1963;Nystrom, 1968;Wernig et al, 1986). This variability has been attributed to differences in fibre size and extent of NMJ fragmentation.…”

Section: Extent Of Overlap Of Nerve Terminal and Motor Endplatementioning

confidence: 94%

Morphology of diaphragm neuromuscular junctions on different fibre types

et al. 1996

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We hypothesize that the morphology of the neuromuscular junction on different muscle fibre types varies, reflecting differences in activation history. In the rat diaphragm muscle, we used a three-colour fluorescent immunocytochemical technique to simultaneously visualize (1) innervating axons and presynaptic nerve terminals, (2) motor endplates, and (3) myosin heavy chain isoform expression (muscle fibre type). Laser-scanning confocal microscopy was then used to optically section the triple-labelled muscle fibres, and create three-dimensional views of the neuromuscular junction. Type I fibres were innervated by the smallest axons, and type IIa, IIx and IIb fibres by progressively larger axons. Absolute planar areas of nerve terminals and endplates progressively increased from type I, IIa, IIx to IIb fibres. When normalized for fibre diameter, planar areas of nerve terminals were largest on type I fibres, with no difference among type II fibres. The normalized planar area of endplates were larger for type I and IIb fibres, compared to type IIa and IIx fibres. The three-dimensional surface area of endplates was largest on type I fibres, with no differences across type II fibres. When normalized for fibre diameter, endplate surface areas increased progressively from type I, IIa, IIx to IIb fibres. The branching patterns of both nerve terminals and endplates varied across fibre types. The number of nerve terminal and endplate branches increased progressively from type I, IIa, IIx to IIb fibres. Conversely, individual branch length was longest on type I fibres, and shortest on type IIb fibres. The extent of overlap of pre- and postsynaptic elements of the neuromuscular junction decreased progressively on type I, IIa, IIx and IIb fibres. We conclude that these morphological differences at the neuromuscular function of different fibre types reflect differences in activation history and may underlie phenotypic differences in neuromuscular transmission.

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Section: Extent Of Overlap Of Nerve Terminal and Motor Endplatementioning

confidence: 94%

Morphology of diaphragm neuromuscular junctions on different fibre types

et al. 1996

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“…Maintenance of synaptic efficacy may be the driving force behind neuromuscular junction remodeling (145,151). In previous studies, our laboratory (85,108,109) found that the changes in diaphragm muscle neuromuscular junction morphology and function induced by C 2 hemisection and tetrodotoxin-induced nerve blockade were quite different.…”

Section: Plasticity At the Neuromuscular Junctionmentioning

confidence: 99%

Invited Review: Mechanisms underlying motor unit plasticity in the respiratory system

Mantilla¹,

Sieck²

2003

Journal of Applied Physiology

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Neuromotor control of skeletal muscles, including respiratory muscles, is ultimately dependent on the function of the motor unit (comprising an individual motoneuron and the muscle fibers it innervates). Considerable diversity exists across diaphragm motor units, yet remarkable homogeneity is present (and maintained) within motor units. In recent years, the mechanisms underlying the development and adaptability of respiratory motor units have received great attention, leading to significant advances in our understanding of diaphragm motor unit plasticity. For example, following imposed inactivity of the diaphragm muscle, there are changes at phrenic motoneurons, neuromuscular junctions, and muscle fibers that tend to restore the ability of the diaphragm to sustain ventilation. The role of activity, neurotrophins, and other growth factors in modulating this adaptability is discussed.

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Fatigue at the Neuromuscular Junction

Sieck

Prakash

1995

Advances in Experimental Medicine and Biology

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A Parametric Study of the Neuromuscular Junction During Ontogenesis and Under Different External Conditions

Cited by 4 publications

References 13 publications

Morphology of diaphragm neuromuscular junctions on different fibre types

Morphology of diaphragm neuromuscular junctions on different fibre types

Invited Review: Mechanisms underlying motor unit plasticity in the respiratory system

Fatigue at the Neuromuscular Junction

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