QUICK SEARCH:   [advanced] Author: Keyword(s):
Home     Help     Feedback     Subscriptions     Archive     Search     Table of Contents

This Article Figures Only Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Kanatous, S. B. Articles by Mathieu-Costello, O. Search for Related Content PubMed PubMed Citation Articles by Kanatous, S. B. Articles by Mathieu-Costello, O. Pubmed/NCBI databases Substance via MeSH Social Bookmarking                         What's this?

The Journal of Experimental Biology 205, 3601-3608 (2002)
Copyright © 2002 The Company of Biologists Limited

Aerobic capacities in the skeletal muscles of Weddell seals: key to longer dive durations?

S. B. Kanatous¹, R. W. Davis², R. Watson², L. Polasek², T. M. Williams³ and O. Mathieu-Costello^4,

¹ Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
² Department of Marine Biology, Texas A&M University, Galveston, TX 77553, USA
³ Department of Biology, University of California Santa Cruz, Santa Cruz, CA 95604, USA
⁴ Department of Medicine, University of California San Diego, San Diego, CA 92093, USA

^* Author for correspondence (e-mail: shane.kanatous{at}utsouthwestern.edu)

Accepted 20 August 2002

In contrast to terrestrial animals that function under hypoxic conditions but display the typical exercise response of increasing ventilation and cardiac output, marine mammals exercise under a different form of hypoxic stress. They function for the duration of a dive under progressive asphyxia, which is the combination of increasing hypoxia, hypercapnia and acidosis. Our previous studies on short-duration, shallow divers found marked adaptations in their skeletal muscles, which culminated in enhanced aerobic capacities that are similar to those of atheltic terrestrial mammals. The purpose of the present study was to assess the aerobic capacity of skeletal muscles from long-duration divers. Swimming and non-swimming muscles were collected from adult Weddell seals, Leptonychotes weddelli, and processed for morphometric analysis, enzymology, myoglobin concentrations and fiber-type distribution. The results showed that the skeletal muscles of Weddell seals do not have enhanced aerobic capacities compared with those of terrestrial mammals but are adapted to maintain low levels of an aerobic lipid-based metabolism, especially under the hypoxic conditions associated with diving. The lower aerobic capacity of Weddell seal muscle as compared with that of shorter-duration divers appears to reflect their energy-conserving modes of locomotion, which enable longer and deeper dives.

Key words: Weddell seals, Leptonychotes weddelli, aerobic capacity, diving, skeletal muscle, mitochondria

CiteULike    Complore    Connotea    Del.icio.us    Digg    Reddit    Technorati    Twitter    What's this?

This article has been cited by other articles:

				S. B. Kanatous, P. P. A. Mammen, P. B. Rosenberg, C. M. Martin, M. D. White, J. M. DiMaio, G. Huang, S. Muallem, and D. J. Garry Hypoxia reprograms calcium signaling and regulates myoglobin expression Am J Physiol Cell Physiol, March 1, 2009; 296(3): C393 - C402. [Abstract] [Full Text] [PDF]

				S. B. Kanatous, T. J. Hawke, S. J. Trumble, L. E. Pearson, R. R. Watson, D. J. Garry, T. M. Williams, and R. W. Davis The ontogeny of aerobic and diving capacity in the skeletal muscles of Weddell seals J. Exp. Biol., August 15, 2008; 211(16): 2559 - 2565. [Abstract] [Full Text] [PDF]

				S. T. Kinsey, K. M. Hardy, and B. R. Locke The long and winding road: influences of intracellular metabolite diffusion on cellular organization and metabolism in skeletal muscle J. Exp. Biol., October 15, 2007; 210(20): 3505 - 3512. [Abstract] [Full Text] [PDF]