Cover Image

Excitation-contraction coupling and mechano-sensitivity in denervated skeletal muscles

Fabio Francini, Roberta Squecco
  • Roberta Squecco
    Department of Physiological Sciences, University of Florence, Italy

Abstract

Skeletal muscle atrophy can be defined as a wasting or decrease in muscle mass and muscle force generation owing lack of use, ageing, injury or disease. Thus, the etiology of atrophy can be different. Atrophy in denervated muscle is a consequence of two factors: 1) the complete lack of motoneuron activity inducing the deficiency of neurotransmitter release and 2) the muscles disuse. The balance of the muscular functions depends on extra- and intra-muscular signals. In the balance are involved the excitation-contraction coupling (ECC), local growth factors, Ca2+-dependent and independent intracellular signals, mechano-sensitivity and mechano-transduction that activate Ca2+-dependent signaling proteins and cytoskeleton- nucleus pathways to the nucleus, that regulate the gene expression. Moreover, retrograde signal from intracellular compartments and cytoskeleton to the sarcolemma are additional factors that regulate the muscle function. Proteolytic systems that operate in atrophic muscles progressively reduce the muscle protein content and so the sarcolemma, ECC and the force generation. In this review we will focus on the more relevant changes of the sarcolemma, excitation-contraction coupling, ECC and mechano-transduction evaluated by electrophysiological methods and observed from early- to long-term denervated skeletal muscles. This review put in particular evidence that long-term denervated muscle maintain a sub-population of fibers with ECC and contractile machinery able to be activated, albeit in lesser amounts, by electrical and mechanical stimulation. Accordingly, this provides a potential molecular explanation of the muscle recovery that occurs in response to rehabilitation strategy as transcutaneous electrical stimulation and passive stretching of denervated muscles, which wre developed as a result of empirical clinical observations.

Keywords

Excitation-contraction coupling; L-type Ca2+ current; Mechano-transduction; Skeletal muscle; Long-term denervation

Full Text:

PDF
Submitted: 2013-07-03 13:41:06
Published: 2010-09-03 00:00:00
Search for citations in Google Scholar
Related articles: Google Scholar
Abstract views:
592

Views:
PDF
348

Article Metrics

Metrics Loading ...

Metrics powered by PLOS ALM


Copyright (c) 2010 Fabio Francini, Roberta Squecco

Creative Commons License
This work is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License.
 
© PAGEPress 2008-2018     -     PAGEPress is a registered trademark property of PAGEPress srl, Italy.     -     VAT: IT02125780185     •     Privacy