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Updated: May 11, 2026
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Quantification of Subcellular Glycogen Distribution in Skeletal Muscle Fibers using Transmission Electron Microscopy
Published on: February 7, 2022
Muscle glycogen stores and fatigue
Niels Ørtenblad1, Håkan Westerblad, Joachim Nielsen
1N. Ørtenblad: Institute of Sports Science and Clinical Biomechanics, University of Southern Denmark, Odense, DK-5230 Odense M, Denmark. nortenblad@health.sdu.dk.
The Journal of Physiology
|May 9, 2013
Summary
Muscle glycogen
Area of Science:
- Exercise Physiology
- Skeletal Muscle Biology
- Cellular Metabolism
Background:
- Carbohydrates, specifically muscle glycogen, are crucial fuels for exercise performance.
- The precise mechanisms linking glycogen depletion to muscle fatigue remain unclear.
- Glycogen is not uniformly distributed but exists in distinct pools within muscle fibers.
Purpose of the Study:
- To investigate the direct relationship between localized glycogen pools and muscle function during fatigue.
- To elucidate the role of myofibrillar glycogen in sarcoplasmic reticulum calcium release.
- To understand how compartmentalized energy turnover affects muscle contractility.
Main Methods:
- Utilized electron microscopy to visualize glycogen distribution in skeletal muscle.
- Examined the association of glycogen pools with myofibrillar proteins and sarcoplasmic reticulum.
- Investigated the impact of glycogen depletion on calcium release dynamics.
Main Results:
- Glycogen is localized in distinct pools, particularly within myofibrils near excitation-contraction coupling proteins.
- Decreased myofibrillar glycogen is directly linked to reduced sarcoplasmic reticulum calcium release during fatigue.
- Evidence supports a role for localized glycogen in regulating muscle contractility and fatigability.
Conclusions:
- Compartmentalized energy turnover and specific glycogen pools are critical for sarcoplasmic reticulum calcium release.
- This localized glycogen plays a key role in muscle contractility and the development of fatigue.
- Further research into glycogen compartmentalization can illuminate mechanisms of muscle fatigue.
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