Rate of force development is Ca2+-dependent and influenced by Ca2+-sensitivity in human single muscle fibres from older adults.
Exp Gerontol
; 150: 111348, 2021 07 15.
Article
en En
| MEDLINE
| ID: mdl-33862138
Natural adult aging is associated with declines in skeletal muscle performance, including impaired Ca2+ sensitivity and a slowing of rapid force production (rate of force redevelopment; ktr). The purpose of this study was to investigate the relationship between impaired Ca2+ sensitivity and ktr of single muscle fibres from young and older adults. Participants included 8 young (22-35 yrs) and 8 older (60-81 yrs) males who were living independently. A percutaneous muscle biopsy of the vastus lateralis of each participant was performed. Single muscle fibre mechanical tests included maximal Ca2+-activated force (Po), force-pCa curves, and ktr. We showed a decrease in pCa50 in old type II fibres compared to young, indicating impaired Ca2+ sensitivity in older adults. The ktr behaved in a Ca2+-dependent manner such that with increasing [Ca2+], ktr increases, to a plateau. Interestingly, ktr was not different between young and old muscle fibres. Furthermore, we found strong associations between pCa50 and ktr in both old type I and type II fibres, such that those fibres with lower Ca2+ sensitivity had a slowed ktr. This Ca2+ association, combined with impaired Ca2+ handling in older adults suggests a potential Ca2+-dependent mechanism affecting the transition from weakly- to strongly-bound cross-bridge states, leading to a decline in skeletal muscle performance. Future research is needed to explore the role alterations to Ca2+ sensitivity/handling could be playing in age-related whole muscle performance declines.
Palabras clave
Texto completo:
1
Bases de datos:
MEDLINE
Asunto principal:
Calcio
/
Contracción Muscular
Tipo de estudio:
Diagnostic_studies
Límite:
Aged
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Humans
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Male
Idioma:
En
Revista:
Exp Gerontol
Año:
2021
Tipo del documento:
Article
País de afiliación:
Canadá