Muscle plasticity of Inuit sled dogs in Greenland
This study examined flexible adjustments of skeletal muscle size, fiber structure, and capillarization in Inuit sled dogs responding to seasonal changes in temperature, exercise and food supply. Inuit dogs pull sleds in winter and are fed regularly throughout this working season. In summer, they rem...
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fthighwire:oai:open-archive.highwire.org:jexbio:212/8/1131 2023-05-15T16:25:30+02:00 Muscle plasticity of Inuit sled dogs in Greenland Gerth, Nadine Sum, Steffen Jackson, Sue Starck, J. Matthias 2009-04-15 00:00:00.0 text/html http://jeb.biologists.org/cgi/content/short/212/8/1131 https://doi.org/10.1242/jeb.028324 en eng Company of Biologists http://jeb.biologists.org/cgi/content/short/212/8/1131 http://dx.doi.org/10.1242/jeb.028324 Copyright (C) 2009, Company of Biologists Research Article TEXT 2009 fthighwire https://doi.org/10.1242/jeb.028324 2015-03-01T00:40:48Z This study examined flexible adjustments of skeletal muscle size, fiber structure, and capillarization in Inuit sled dogs responding to seasonal changes in temperature, exercise and food supply. Inuit dogs pull sleds in winter and are fed regularly throughout this working season. In summer, they remain chained to rocks without exercise, receiving food intermittently and often fasting for several days. We studied two dog teams in Northern Greenland (Qaanaaq) where dogs are still draught animals vital to Inuit hunters, and one dog team in Western Greenland (Qeqertarsuaq) where this traditional role has been lost. Northern Greenland dogs receive more and higher quality food than those in Western Greenland. We used ultrasonography for repeated muscle size measurements on the same individuals, and transmission electron microscopy on micro-biopsies for summer–winter comparisons of muscle histology, also within individuals. At both study sites, dogs' muscles were significantly thinner in summer than in winter – atrophy attributable to reduced fiber diameter. Sarcomeres from West Greenland dogs showed serious myofilament depletion and expansion of the sarcoplasmatic space between myofibrils during summer. At both study sites, summer samples showed fewer interfibrillar and subsarcolemmal mitochondria, and fewer lipid droplets between myofibrils, than did winter samples. In summer, capillary density was higher and inter-capillary distance smaller than in winter, but the capillary-to-fiber-ratio and number of capillaries associated with single myofibers were constant. Increased capillary density was probably a by-product of differential tissue responses to condition changes rather than a functional adaptation, because thinning of muscle fibers in summer was not accompanied by reduction in the capillary network. Thus, skeletal muscle of Inuit dogs responds flexibly to changes in functional demands. This flexibility is based on differential changes in functional components: mitochondrial numbers, lipid droplet size, and the ... Text Greenland inuit Qaanaaq Qeqertarsuaq HighWire Press (Stanford University) Greenland Qaanaaq ENVELOPE(-69.232,-69.232,77.467,77.467) Qeqertarsuaq ENVELOPE(-56.867,-56.867,74.400,74.400) Journal of Experimental Biology 212 8 1131 1139 |
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Research Article Gerth, Nadine Sum, Steffen Jackson, Sue Starck, J. Matthias Muscle plasticity of Inuit sled dogs in Greenland |
topic_facet |
Research Article |
description |
This study examined flexible adjustments of skeletal muscle size, fiber structure, and capillarization in Inuit sled dogs responding to seasonal changes in temperature, exercise and food supply. Inuit dogs pull sleds in winter and are fed regularly throughout this working season. In summer, they remain chained to rocks without exercise, receiving food intermittently and often fasting for several days. We studied two dog teams in Northern Greenland (Qaanaaq) where dogs are still draught animals vital to Inuit hunters, and one dog team in Western Greenland (Qeqertarsuaq) where this traditional role has been lost. Northern Greenland dogs receive more and higher quality food than those in Western Greenland. We used ultrasonography for repeated muscle size measurements on the same individuals, and transmission electron microscopy on micro-biopsies for summer–winter comparisons of muscle histology, also within individuals. At both study sites, dogs' muscles were significantly thinner in summer than in winter – atrophy attributable to reduced fiber diameter. Sarcomeres from West Greenland dogs showed serious myofilament depletion and expansion of the sarcoplasmatic space between myofibrils during summer. At both study sites, summer samples showed fewer interfibrillar and subsarcolemmal mitochondria, and fewer lipid droplets between myofibrils, than did winter samples. In summer, capillary density was higher and inter-capillary distance smaller than in winter, but the capillary-to-fiber-ratio and number of capillaries associated with single myofibers were constant. Increased capillary density was probably a by-product of differential tissue responses to condition changes rather than a functional adaptation, because thinning of muscle fibers in summer was not accompanied by reduction in the capillary network. Thus, skeletal muscle of Inuit dogs responds flexibly to changes in functional demands. This flexibility is based on differential changes in functional components: mitochondrial numbers, lipid droplet size, and the ... |
format |
Text |
author |
Gerth, Nadine Sum, Steffen Jackson, Sue Starck, J. Matthias |
author_facet |
Gerth, Nadine Sum, Steffen Jackson, Sue Starck, J. Matthias |
author_sort |
Gerth, Nadine |
title |
Muscle plasticity of Inuit sled dogs in Greenland |
title_short |
Muscle plasticity of Inuit sled dogs in Greenland |
title_full |
Muscle plasticity of Inuit sled dogs in Greenland |
title_fullStr |
Muscle plasticity of Inuit sled dogs in Greenland |
title_full_unstemmed |
Muscle plasticity of Inuit sled dogs in Greenland |
title_sort |
muscle plasticity of inuit sled dogs in greenland |
publisher |
Company of Biologists |
publishDate |
2009 |
url |
http://jeb.biologists.org/cgi/content/short/212/8/1131 https://doi.org/10.1242/jeb.028324 |
long_lat |
ENVELOPE(-69.232,-69.232,77.467,77.467) ENVELOPE(-56.867,-56.867,74.400,74.400) |
geographic |
Greenland Qaanaaq Qeqertarsuaq |
geographic_facet |
Greenland Qaanaaq Qeqertarsuaq |
genre |
Greenland inuit Qaanaaq Qeqertarsuaq |
genre_facet |
Greenland inuit Qaanaaq Qeqertarsuaq |
op_relation |
http://jeb.biologists.org/cgi/content/short/212/8/1131 http://dx.doi.org/10.1242/jeb.028324 |
op_rights |
Copyright (C) 2009, Company of Biologists |
op_doi |
https://doi.org/10.1242/jeb.028324 |
container_title |
Journal of Experimental Biology |
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212 |
container_issue |
8 |
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1131 |
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1139 |
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1766014272751534080 |