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Updated: Feb 15, 2026

Evaluation of Muscle Function of the Extensor Digitorum Longus Muscle Ex vivo and Tibialis Anterior Muscle In situ in Mice
Published on: February 9, 2013
Aging impairs regulation of ryanodine receptors from extensor digitorum longus but not soleus muscles
Angela J Gaboardi1, Jochen Kressler2, Teresa K Snow1
1School of Applied Physiology, Georgia Institute of Technology, 281 Ferst Drive, Atlanta, GA, 30332, USA.
Introduction:
Because impaired excitation-contraction coupling and reduced sarcoplasmic reticulum (SR) Ca2+ release may contribute to the age-associated decline in skeletal muscle strength, we investigated the effect of aging on regulation of the skeletal muscle isoform of the ryanodine receptor (RyR1) by physiological channel ligands.
Methods:
[3 H]Ryanodine binding to membranes from 8- and 26-month-old Fischer 344 extensor digitorum longus (EDL) and soleus muscles was used to investigate the effects of age on RyR1 modulation by Ca2+ and calmodulin (CaM).
Results:
Aging reduced maximal Ca2+ -stimulated binding to EDL membranes. In 0.3 μM Ca2+ , age reduced binding and CaM increased binding to EDL membranes. In 300 μM Ca2+ , CaM reduced binding, but the age effect was not significant. Aging did not affect Ca2+ or CaM regulation of soleus RyR1.
Discussion:
In aged fast-twitch muscle, impaired RyR1 Ca2+ regulation may contribute to lower SR Ca2+ release and reduced muscle function. Muscle Nerve 57: 1022-1025, 2018.
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