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Ex Vivo Assessment of Contractility, Fatigability and Alternans in Isolated Skeletal Muscles
14:02

Ex Vivo Assessment of Contractility, Fatigability and Alternans in Isolated Skeletal Muscles

Published on: November 1, 2012

[Changes in the contractile properties of tonic muscle fibers following denervation]

I B Lapshina, G A Nasledov

    Fiziologicheskii Zhurnal SSSR Imeni I. M. Sechenova
    |August 1, 1978
    PubMed

    Insights

    Denervation impairs tonic muscle fibers ability to maintain potassium and acetylcholine contractures. Muscle relaxation processes and potassium contracture activation mechanisms are primarily affected, while acetylcholine contracture mechanisms remain intact.

    Area of Science:

    • Muscle physiology
    • Neuroscience
    • Cellular biology

    Background:

    • Tonic muscle fibers exhibit unique contractile properties.
    • Denervation significantly alters muscle fiber function.
    • Understanding fiber response to chemical stimuli post-denervation is crucial.

    Purpose of the Study:

    • To investigate the effects of denervation on tonic muscle fiber contracture.
    • To compare the responses to potassium and acetylcholine in denervated versus intact fibers.
    • To elucidate the specific mechanisms affected by denervation.

    Main Methods:

    • Tonic muscle fiber preparation.
    • Assessment of contracture responses to potassium and acetylcholine.
    • Analysis of mechanical tension, amplitude, speed of development, and latency.
    • Comparison between denervated and intact muscle fibers.

    Main Results:

    • Denervated tonic fibers show reduced ability to sustain potassium (K) and acetylcholine (A) contractures.
    • Maximal mechanical tension is decreased in denervated fibers for both K and A.
    • Caffeine contracture parameters (amplitude, speed, latency) remain largely unchanged.
    • Potassium contracture speed decreases and latency increases post-denervation.
    • Acetylcholine contracture parameters show minimal changes after denervation.

    Conclusions:

    • Denervation primarily impacts tonic muscle fiber relaxation processes.
    • Mechanisms for potassium contracture activation are altered by denervation.
    • Mechanisms for acetylcholine contracture activation appear preserved after denervation.

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