Ontogenetic changes in skeletal muscle fiber type, fiber diameter and myoglobin concentration in the Northern elephant seal (Mirounga angustirostris)
Moore, Colby D.
Crocker, Daniel E.
Moore, Michael J.
Willoughby, Darryn S.
Robbins, Kathleen A.
Kanatous, Shane B.
Trumble, Stephen J.
MetadataShow full item record
Northern elephant seals (Mirounga angustirostris) (NES) are known to be deep, long-duration divers and to sustain long-repeated patterns of breath-hold, or apnea. Some phocid dives remain within the bounds of aerobic metabolism, accompanied by physiological responses inducing lung compression, bradycardia, and peripheral vasoconstriction. Current data suggest an absence of type IIb fibers in pinniped locomotory musculature. To date, no fiber type data exist for NES, a consummate deep diver. In this study, NES were biopsied in the wild. Ontogenetic changes in skeletal muscle were revealed through succinate dehydrogenase (SDH) based fiber typing. Results indicated a predominance of uniformly shaped, large type I fibers and elevated myoglobin (Mb) concentrations in the longissimus dorsi (LD) muscle of adults. No type II muscle fibers were detected in any adult sampled. This was in contrast to the juvenile animals that demonstrated type II myosin in Western Blot analysis, indicative of an ontogenetic change in skeletal muscle with maturation. These data support previous hypotheses that the absence of type II fibers indicates reliance on aerobic metabolism during dives, as well as a depressed metabolic rate and low energy locomotion. We also suggest that the lack of type IIb fibers (adults) may provide a protection against ischemia reperfusion (IR) injury in vasoconstricted peripheral skeletal muscle.
© The Author(s), 2014. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Frontiers in Physiology 5 (2014): 217, doi:10.3389/fphys.2014.00217.
The following license files are associated with this item:
Showing items related by title, author, creator and subject.
Rieder, Conly L. (2005-09-12)The attachment to and movement of a chromosome on the mitotic spindle is mediated by the formation of a bundle of microtubules (MTs) that tethers the kinetochore on the chromosome to a spindle pole. The origin of these ...
Ahn, Soohyoun; Kulis, David M.; Erdner, Deana L.; Anderson, Donald M.; Walt, David R. (American Society for Microbiology, 2006-09)Harmful algal blooms (HABs) are a serious threat to coastal resources, causing a variety of impacts on public health, regional economies, and ecosystems. Plankton analysis is a valuable component of many HAB monitoring and ...
Bowen, Martin F. (Woods Hole Oceanographic Institution, 2001-06)Neutral tethers for unmanned underwater vehicles may contain a bundle of single-mode, optical fibers that are protected inside flexible stainless steel tubing. To date the author knows of no commercially available systems ...