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Initiating treadmill training in late middle age offers modest adaptations in Ca²⁺ handling but enhances oxidative damage in senescent rat skeletal muscle

journal contribution
posted on 2010-05-01, 00:00 authored by Melissa M Thomas, Chris Vigna, Andrew BetikAndrew Betik, A Russell Tupling, Russell T Hepple
Aging skeletal muscle shows an increased time to peak force and relaxation and a decreased specific force, all of which could relate to changes in muscle Ca(2+) handling. The purpose of this study was to determine if Ca(2+)-handling protein content and function are decreased in senescent gastrocnemius muscle and if initiating a training program in late middle age (LMA, 29 mo old) could improve function in senescent (34- to 36-mo-old) muscle. LMA male Fischer 344 x Brown-Norway rats underwent 5-7 mo of treadmill training. Aging resulted in a decrease in maximal sarco(endo)plasmic reticulum Ca(2+)-ATPase (SERCA) activity and a decrease in Ca(2+) release rate but no change in Ca(2+) uptake rate. Efficiency of the Ca(2+) pump was increased with age, as was the content of SERCA2a. Training caused a further increase in SERCA2a content. Aging also caused an increase in protein carbonyl and reactive nitrogen species damage accumulation, and both further increased with training. Consistent with the increase in oxidative damage, heat shock protein 70 content was increased with age and further increased with training. Together, these results suggest that while initiating exercise training in LMA augments the age-related increase in expression of heat shock protein 70 and the more efficient SERCA2a isoform, it did not prevent the decrease in SERCA activity and exacerbated oxidative damage in senescent gastrocnemius muscle.

History

Journal

American journal of physiology: regulatory, integrative and comparative physiology

Volume

298

Pagination

R1269-R1278

Location

Bethesda, Md.

eISSN

1522-1490

Language

eng

Publication classification

C1.1 Refereed article in a scholarly journal

Copyright notice

2010, the American Physiological Society

Issue

5

Publisher

The American Physiological Society

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