Journal article
Minimal seasonal alterations in the skeletal muscle of captive brown bears
Physiological and biochemical zoology, Vol.81(2), pp.138-147
03/2008
Handle:
https://hdl.handle.net/2376/110581
PMID: 18173360
Abstract
Abstract Previous studies on wild black bears (Ursus americanus) have shown that skeletal muscle morphology, composition, and overall force-generating capacity do not differ drastically between seasons despite prolonged inactivity during hibernation. However, the amount and characteristics of the seasonal variations were not consistent in these studies. The goals of this study were to compare the amount of muscle atrophy in captive brown bears (Ursus arctos) with that observed in wild black bears and measure seasonal differences in twitch characteristics. Samples from the biceps femoris muscle were collected during the summer and winter. Protein concentration, fiber-type composition, and fiber cross-sectional area were measured along with twitch characteristics. The protein concentration of the winter samples was 8.2% lower than that of the summer samples; fiber cross-sectional area and the relative proportion of fast and slow fibers remained unchanged between seasons. Myosin heavy chain isoforms I, IIa, and IIx were identified by immunoblotting and electrophoresis, and the proportions did not change between seasons. The half-rise time in the twitch contractions increased in winter relative to summer samples, which is unexpected under disuse conditions. These results agreed with a study that showed minimal skeletal muscle atrophy between seasons in wild black bears.
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Details
- Title
- Minimal seasonal alterations in the skeletal muscle of captive brown bears
- Creators
- John D Hershey - Department of Veterinary Comparative Anatomy, Pharmacology and Physiology, Washington State University, Pullman, Washington 99164, USACharles T RobbinsO Lynne NelsonDavid C Lin
- Publication Details
- Physiological and biochemical zoology, Vol.81(2), pp.138-147
- Academic Unit
- Environment, School of the (CAHNRS); Chemical Engineering and Bioengineering, School of
- Publisher
- United States
- Identifiers
- 99900547293201842
- Language
- English
- Resource Type
- Journal article