scholarly journals Impaired muscle spindle function in murine models of muscular dystrophy

2020 ◽  
Vol 598 (8) ◽  
pp. 1591-1609 ◽  
Author(s):  
Laura Gerwin ◽  
Sarah Rossmanith ◽  
Corinna Haupt ◽  
Jürgen Schultheiß ◽  
Heinrich Brinkmeier ◽  
...  
Keyword(s):  
Muscular Dystrophy ◽  
Muscle Spindle ◽  
Murine Models ◽  
Spindle Function

scholarly journals The effects of vibration-induced altered stretch reflex sensitivity on maximal motor unit firing properties

2019 ◽  
Vol 121 (6) ◽  
pp. 2215-2221 ◽  
Author(s):  
Alejandra Barrera-Curiel ◽  
Ryan J. Colquhoun ◽  
Jesus A. Hernandez-Sarabia ◽  
Jason M. DeFreitas
Keyword(s):  
Motor Unit ◽  
Muscle Spindle ◽  
Stretch Reflex ◽  
Muscle Spindles ◽  
Motor Unit Action Potential ◽  
Firing Rates ◽  
Motor Unit Firing ◽  
Firing Properties ◽  
Spindle Function ◽  
Voluntary Strength

It is well known that muscle spindles have a monosynaptic, excitatory connection with α-motoneurons. However, the influence of muscle spindles on human motor unit behavior during maximal efforts remains untested. It has also been shown that muscle spindle function, as assessed by peripheral reflexes, can be systematically manipulated with muscle vibration. Therefore, the purpose of this study was to analyze the effects of brief and prolonged vibration on maximal motor unit firing properties. A crossover design was used, in which each of the 24 participants performed one to three maximal knee extensions under three separate conditions: 1) control, 2) brief vibration that was applied during the contraction, and 3) after prolonged vibration that was applied for ~20 min before the contraction. Multichannel EMG was recorded from the vastus lateralis during each contraction and was decomposed into its constituent motor unit action potential trains. Surprisingly, an approximate 9% reduction in maximal voluntary strength was observed not only after prolonged vibration but also during brief vibration. In addition, both vibration conditions had a large, significant effect on firing rates (a decrease in the rates) and a small to moderate, nonsignificant effect on recruitment thresholds (a small increase in the thresholds). Therefore, vibration had a detrimental influence on both maximal voluntary strength and motor unit firing properties, which we propose is due to altered function of the stretch reflex pathway. NEW & NOTEWORTHY We used vibration to alter muscle spindle function and examined the vibration’s influence on maximal motor unit properties. We discovered that vibration had a detrimental influence on motor unit behavior and motor output by decreasing motor unit firing rates, increasing recruitment thresholds, which led to decreased maximal strength. We believe that understanding the role of muscle spindles during maximal contractions provides a deeper insight into motor control and sensorimotor integration.

scholarly journals Mutation-independent Proteomic Signatures of Pathological Progression in Murine Models of Duchenne Muscular Dystrophy

2020 ◽  
Vol 19 (12) ◽  
pp. 2047-2067
Author(s):  
Tirsa L. E. van Westering ◽  
Henrik J. Johansson ◽  
Britt Hanson ◽  
Anna M. L. Coenen-Stass ◽  
Yulia Lomonosova ◽  
...  
Keyword(s):  
Duchenne Muscular Dystrophy ◽  
Muscular Dystrophy ◽  
Muscle Growth ◽  
Differentially Expressed ◽  
Murine Models ◽  
Dystrophic Muscle ◽  
C2c12 Myoblasts ◽  
Experimental Therapies ◽  
Dystrophin Protein ◽  
Upstream Regulators

The absence of the dystrophin protein in Duchenne muscular dystrophy (DMD) results in myofiber fragility and a plethora of downstream secondary pathologies. Although a variety of experimental therapies are in development, achieving effective treatments for DMD remains exceptionally challenging, not least because the pathological consequences of dystrophin loss are incompletely understood. Here we have performed proteome profiling in tibialis anterior muscles from two murine DMD models (mdx and mdx52) at three ages (8, 16, and 80 weeks of age), all n = 3. High-resolution isoelectric focusing liquid chromatography-tandem MS (HiRIEF-LC–MS/MS) was used to quantify the expression of 4974 proteins across all 27 samples. The two dystrophic models were found to be highly similar, whereas multiple proteins were differentially expressed relative to WT (C57BL/6) controls at each age. Furthermore, 1795 proteins were differentially expressed when samples were pooled across ages and dystrophic strains. These included numerous proteins associated with the extracellular matrix and muscle function that have not been reported previously. Pathway analysis revealed multiple perturbed pathways and predicted upstream regulators, which together are indicative of cross-talk between inflammatory, metabolic, and muscle growth pathways (e.g. TNF, INFγ, NF-κB, SIRT1, AMPK, PGC-1α, PPARs, ILK, and AKT/PI3K). Upregulation of CAV3, MVP and PAK1 protein expression was validated in dystrophic muscle by Western blot. Furthermore, MVP was upregulated during, but not required for, the differentiation of C2C12 myoblasts suggesting that this protein may affect muscle regeneration. This study provides novel insights into mutation-independent proteomic signatures characteristic of the dystrophic phenotype and its progression with aging.

Muscle spindle function during movement

1980 ◽  
Vol 3 (11) ◽  
pp. 251-253 ◽  
Author(s):  
David Burke
Keyword(s):  
Muscle Spindle ◽  
Spindle Function

The effects of concentric and eccentric training in murine models of dysferlin‐associated muscular dystrophy

2020 ◽  
Vol 62 (3) ◽  
pp. 393-403
Author(s):  
Morium Begam ◽  
Renuka Roche ◽  
Joshua J. Hass ◽  
Chantel A. Basel ◽  
Jacob M. Blackmer ◽  
...  
Keyword(s):  
Muscular Dystrophy ◽  
Murine Models ◽  
Eccentric Training

Muscle spindle function in organophosphorus neuropathy

1980 ◽  
Vol 185 (1) ◽  
pp. 77-84 ◽  
Author(s):  
Thomas Baker ◽  
Herbert E. Lowndes
Keyword(s):  
Muscle Spindle ◽  
Spindle Function
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