Skeletal muscles of hibernating brown bears are unusually resistant to effects of denervation
Hibernating bears retain most of their skeletal muscle strength despite drastically reduced weight-bearing activity. Regular neural activation of muscles is a potential mechanism by which muscle atrophy could be limited. However, both mechanical loading and neural activity are usually necessary to m...
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fthighwire:oai:open-archive.highwire.org:jexbio:215/12/2081 2023-05-15T18:42:11+02:00 Skeletal muscles of hibernating brown bears are unusually resistant to effects of denervation Lin, David C. Hershey, John D. Mattoon, John S. Robbins, Charles T. 2012-06-15 00:00:00.0 text/html http://jeb.biologists.org/cgi/content/short/215/12/2081 https://doi.org/10.1242/jeb.066134 en eng Company of Biologists http://jeb.biologists.org/cgi/content/short/215/12/2081 http://dx.doi.org/10.1242/jeb.066134 Copyright (C) 2012, Company of Biologists Research Articles TEXT 2012 fthighwire https://doi.org/10.1242/jeb.066134 2013-05-26T19:02:57Z Hibernating bears retain most of their skeletal muscle strength despite drastically reduced weight-bearing activity. Regular neural activation of muscles is a potential mechanism by which muscle atrophy could be limited. However, both mechanical loading and neural activity are usually necessary to maintain muscle size. An alternative mechanism is that the signaling pathways related to the regulation of muscle size could be altered so that neither mechanical nor neural inputs are needed for retaining strength. More specifically, we hypothesized that muscles in hibernating bears are resistant to a severe reduction in neural activation. To test this hypothesis, we unilaterally transected the common peroneal nerve, which innervates ankle flexor muscles, in hibernating and summer-active brown bears ( Ursus arctos ). In hibernating bears, the long digital extensor (LDE) and cranial tibial (CT) musculotendon masses on the denervated side decreased after 11 weeks post-surgery by 18±11 and 25±10%, respectively, compared with those in the intact side. In contrast, decreases in musculotendon masses of summer-active bears after denervation were 61±4 and 58±5% in the LDE and CT, respectively, and significantly different from those of hibernating bears. The decrease due to denervation in summer-active bears was comparable to that occurring in other mammals. Whole-muscle cross-sectional areas (CSAs) measured from ultrasound images and myofiber CSAs measured from biopsies decreased similarly to musculotendon mass. Thus, hibernating bears alter skeletal muscle catabolic pathways regulated by neural activity, and exploration of these pathways may offer potential solutions for disuse atrophy of muscles. Text Ursus arctos HighWire Press (Stanford University) Journal of Experimental Biology 215 12 2081 2087 |
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English |
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Research Articles |
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Research Articles Lin, David C. Hershey, John D. Mattoon, John S. Robbins, Charles T. Skeletal muscles of hibernating brown bears are unusually resistant to effects of denervation |
topic_facet |
Research Articles |
description |
Hibernating bears retain most of their skeletal muscle strength despite drastically reduced weight-bearing activity. Regular neural activation of muscles is a potential mechanism by which muscle atrophy could be limited. However, both mechanical loading and neural activity are usually necessary to maintain muscle size. An alternative mechanism is that the signaling pathways related to the regulation of muscle size could be altered so that neither mechanical nor neural inputs are needed for retaining strength. More specifically, we hypothesized that muscles in hibernating bears are resistant to a severe reduction in neural activation. To test this hypothesis, we unilaterally transected the common peroneal nerve, which innervates ankle flexor muscles, in hibernating and summer-active brown bears ( Ursus arctos ). In hibernating bears, the long digital extensor (LDE) and cranial tibial (CT) musculotendon masses on the denervated side decreased after 11 weeks post-surgery by 18±11 and 25±10%, respectively, compared with those in the intact side. In contrast, decreases in musculotendon masses of summer-active bears after denervation were 61±4 and 58±5% in the LDE and CT, respectively, and significantly different from those of hibernating bears. The decrease due to denervation in summer-active bears was comparable to that occurring in other mammals. Whole-muscle cross-sectional areas (CSAs) measured from ultrasound images and myofiber CSAs measured from biopsies decreased similarly to musculotendon mass. Thus, hibernating bears alter skeletal muscle catabolic pathways regulated by neural activity, and exploration of these pathways may offer potential solutions for disuse atrophy of muscles. |
format |
Text |
author |
Lin, David C. Hershey, John D. Mattoon, John S. Robbins, Charles T. |
author_facet |
Lin, David C. Hershey, John D. Mattoon, John S. Robbins, Charles T. |
author_sort |
Lin, David C. |
title |
Skeletal muscles of hibernating brown bears are unusually resistant to effects of denervation |
title_short |
Skeletal muscles of hibernating brown bears are unusually resistant to effects of denervation |
title_full |
Skeletal muscles of hibernating brown bears are unusually resistant to effects of denervation |
title_fullStr |
Skeletal muscles of hibernating brown bears are unusually resistant to effects of denervation |
title_full_unstemmed |
Skeletal muscles of hibernating brown bears are unusually resistant to effects of denervation |
title_sort |
skeletal muscles of hibernating brown bears are unusually resistant to effects of denervation |
publisher |
Company of Biologists |
publishDate |
2012 |
url |
http://jeb.biologists.org/cgi/content/short/215/12/2081 https://doi.org/10.1242/jeb.066134 |
genre |
Ursus arctos |
genre_facet |
Ursus arctos |
op_relation |
http://jeb.biologists.org/cgi/content/short/215/12/2081 http://dx.doi.org/10.1242/jeb.066134 |
op_rights |
Copyright (C) 2012, Company of Biologists |
op_doi |
https://doi.org/10.1242/jeb.066134 |
container_title |
Journal of Experimental Biology |
container_volume |
215 |
container_issue |
12 |
container_start_page |
2081 |
op_container_end_page |
2087 |
_version_ |
1766231799930814464 |