Revisiting specific force loss in human permeabilised single skeletal muscle fibres obtained from older individuals
| Autor: | Michaeljohn Kalakoutis, Ross D. Pollock, Norman R. Lazarus, R Andrew Atkinson, Marc George, Onur Berber, Roger C. Woledge, Julien Ochala, Stephen D.R. Harridge |
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| Rok vydání: | 2023 |
| Předmět: | |
| Zdroj: | American Journal of Physiology-Cell Physiology. |
| ISSN: | 1522-1563 0363-6143 |
| Popis: | Specific force (SF) has been shown to be reduced in some but not all studies of human ageing using chemically skinned single muscle fibres. This may be due in part to the health status/physical activity levels of different older cohorts, but also from methodological differences in studying skinned fibres. The aim of the present study was to compare SF in fibres from older hip fracture patients (HFP), healthy master cyclists (MC) and healthy non-trained young adults (YA) using two different activating solutions. Quadriceps muscle samples and 316 fibres were obtained from HFPs (74.6±4 years, n=5), MCs (74.8±1, n=5) and YA (25.5±2, n=6). Fibres were activated (pCa 4.5, 15oC) in solutions containing either 60 mM TES or 20 mM imidazole. SF was determined by normalising force to fibre CSA assuming either an elliptical or circular shape and to fibre myosin heavy chain content. Activation in TES resulted in significantly higher MHC-I SF in all groups and YA MHC-IIA fibres, irrespective of normalisation method. Whilst there were no differences in SF between the participant groups, the ratio of SF between the TES and imidazole solutions was lower in HFPs compared to YAs (MHC-I p |
| Databáze: | OpenAIRE |
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