Cargando…
Thixotropy and Rheopexy of Muscle Fibers Probed Using Sinusoidal Oscillations
Length changes of muscle fibers have previously been shown to result in a temporary reduction in fiber stiffness that is referred to as thixotropy. Understanding the mechanism of this thixotropy is important to our understanding of muscle function since there are many instances in which muscle is su...
Autores principales: | , , |
---|---|
Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
Public Library of Science
2015
|
Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4400131/ https://www.ncbi.nlm.nih.gov/pubmed/25880774 http://dx.doi.org/10.1371/journal.pone.0121726 |
_version_ | 1782366995071631360 |
---|---|
author | Altman, David Minozzo, Fabio C. Rassier, Dilson E. |
author_facet | Altman, David Minozzo, Fabio C. Rassier, Dilson E. |
author_sort | Altman, David |
collection | PubMed |
description | Length changes of muscle fibers have previously been shown to result in a temporary reduction in fiber stiffness that is referred to as thixotropy. Understanding the mechanism of this thixotropy is important to our understanding of muscle function since there are many instances in which muscle is subjected to repeated patterns of lengthening and shortening. By applying sinusoidal length changes to one end of single permeabilized muscle fibers and measuring the force response at the opposite end, we studied the history-dependent stiffness of both relaxed and activated muscle fibers. For length change oscillations greater than 1 Hz, we observed thixotropic behavior of activated fibers. Treatment of these fibers with EDTA and blebbistatin, which inhibits myosin-actin interactions, quashed this effect, suggesting that the mechanism of muscle fiber thixotropy is cross-bridge dependent. We modeled a half-sarcomere experiencing sinusoidal length changes, and our simulations suggest that thixotropy could arise from force-dependent cross-bridge kinetics. Surprisingly, we also observed that, for length change oscillations less than 1 Hz, the muscle fiber exhibited rheopexy. In other words, the stiffness of the fiber increased in response to the length changes. Blebbistatin and EDTA did not disrupt the rheopectic behavior, suggesting that a non-cross-bridge mechanism contributes to this phenomenon. |
format | Online Article Text |
id | pubmed-4400131 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2015 |
publisher | Public Library of Science |
record_format | MEDLINE/PubMed |
spelling | pubmed-44001312015-04-21 Thixotropy and Rheopexy of Muscle Fibers Probed Using Sinusoidal Oscillations Altman, David Minozzo, Fabio C. Rassier, Dilson E. PLoS One Research Article Length changes of muscle fibers have previously been shown to result in a temporary reduction in fiber stiffness that is referred to as thixotropy. Understanding the mechanism of this thixotropy is important to our understanding of muscle function since there are many instances in which muscle is subjected to repeated patterns of lengthening and shortening. By applying sinusoidal length changes to one end of single permeabilized muscle fibers and measuring the force response at the opposite end, we studied the history-dependent stiffness of both relaxed and activated muscle fibers. For length change oscillations greater than 1 Hz, we observed thixotropic behavior of activated fibers. Treatment of these fibers with EDTA and blebbistatin, which inhibits myosin-actin interactions, quashed this effect, suggesting that the mechanism of muscle fiber thixotropy is cross-bridge dependent. We modeled a half-sarcomere experiencing sinusoidal length changes, and our simulations suggest that thixotropy could arise from force-dependent cross-bridge kinetics. Surprisingly, we also observed that, for length change oscillations less than 1 Hz, the muscle fiber exhibited rheopexy. In other words, the stiffness of the fiber increased in response to the length changes. Blebbistatin and EDTA did not disrupt the rheopectic behavior, suggesting that a non-cross-bridge mechanism contributes to this phenomenon. Public Library of Science 2015-04-16 /pmc/articles/PMC4400131/ /pubmed/25880774 http://dx.doi.org/10.1371/journal.pone.0121726 Text en © 2015 Altman et al http://creativecommons.org/licenses/by/4.0/ This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are properly credited. |
spellingShingle | Research Article Altman, David Minozzo, Fabio C. Rassier, Dilson E. Thixotropy and Rheopexy of Muscle Fibers Probed Using Sinusoidal Oscillations |
title | Thixotropy and Rheopexy of Muscle Fibers Probed Using Sinusoidal Oscillations |
title_full | Thixotropy and Rheopexy of Muscle Fibers Probed Using Sinusoidal Oscillations |
title_fullStr | Thixotropy and Rheopexy of Muscle Fibers Probed Using Sinusoidal Oscillations |
title_full_unstemmed | Thixotropy and Rheopexy of Muscle Fibers Probed Using Sinusoidal Oscillations |
title_short | Thixotropy and Rheopexy of Muscle Fibers Probed Using Sinusoidal Oscillations |
title_sort | thixotropy and rheopexy of muscle fibers probed using sinusoidal oscillations |
topic | Research Article |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4400131/ https://www.ncbi.nlm.nih.gov/pubmed/25880774 http://dx.doi.org/10.1371/journal.pone.0121726 |
work_keys_str_mv | AT altmandavid thixotropyandrheopexyofmusclefibersprobedusingsinusoidaloscillations AT minozzofabioc thixotropyandrheopexyofmusclefibersprobedusingsinusoidaloscillations AT rassierdilsone thixotropyandrheopexyofmusclefibersprobedusingsinusoidaloscillations |