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Updated: Oct 7, 2026

Ex Vivo Assessment of Contractility, Fatigability and Alternans in Isolated Skeletal Muscles
Published on: November 1, 2012
Oligomeric status of the dihydropyridine receptor in aged skeletal muscle
M Ryan1, B M Carlson, K Ohlendieck
1Department of Pharmacology, University College Dublin, Dublin, Belfield, 4, Ireland.
Abstract:
A prominent feature of aging is represented by a decrease in muscle mass and strength. Abnormalities in Ca2+ -regulatory membrane complexes are involved in many muscular disorders. In analogy, we determined potential age-related changes in a key component of excitation-contraction coupling, the dihydropyridine receptor. Immunoblotting of the microsomal fraction from aged rabbit muscle revealed a drastic decline in the voltage-sensing alpha1-subunit of this transverse-tubular receptor, but only marginally altered expression of its auxiliary alpha(2)-subunit and the Na+/K+ -ATPase. A shift to slower fibre type characteristics was indicated by an age-related increase in the slow calsequestrin isoform. Chemical crosslinking analysis showed that the triad receptor complex has a comparable tendency of protein-protein interactions in young and aged muscles. Hence, a reduced expression and not modified oligomerization of the principal dihydropyridine receptor subunit might be involved in triggering impaired triadic signal transduction and abnormal Ca2+ -homeostasis resulting in a progressive functional decline of skeletal muscles.
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