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08:32
Quantification of Subcellular Glycogen Distribution in Skeletal Muscle Fibers using Transmission Electron Microscopy
Published on: February 7, 2022
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Muscle glycogen and cell function--Location, location, location.
N Ørtenblad1,2, J Nielsen1
1Department of Sports Science and Clinical Biomechanics, SDU Muscle Research Cluster, University of Southern Denmark, Odense, Denmark.
Scandinavian Journal of Medicine & Science in Sports
|November 22, 2015
Summary
Glycogen, a key exercise fuel, exists in distinct pools within skeletal muscle fibers. Understanding glycogen
Area of Science:
- Exercise Physiology
- Skeletal Muscle Biology
- Cellular Metabolism
Background:
- Glycogen is a crucial fuel source during exercise.
- Electron microscopy reveals glycogen's non-uniform distribution in muscle fibers, forming distinct pools.
- The subcellular localization of glycogen is increasingly recognized as important for muscle function.
Purpose of the Study:
- To review the evidence on glycogen's subcellular localization in skeletal muscle.
- To discuss the functional implications of glycogen pools in muscle fibers.
- To explore the link between glycogen availability and excitation-contraction coupling.
Main Methods:
- Review of existing literature on glycogen localization and function.
- Analysis of studies using electron microscopy to visualize glycogen distribution.
- Integration of data on factors influencing glycogen pool dynamics.
Main Results:
- Glycogen distribution varies with exercise intensity, fiber type, training, and immobilization.
- Specific glycogen pools appear to have distinct cellular functions.
- Reduced glycogen in these pools correlates with impaired SR Ca(2+) release, slower muscle relaxation, and reduced membrane excitability.
Conclusions:
- Subcellular glycogen localization is critical for understanding its metabolic role and signaling in skeletal muscle.
- The localization and availability of glycogen pools influence excitation-contraction coupling.
- Muscle glycogen levels may act as an intrinsic mechanism linking energy status to energy use in muscle fibers.
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