Mitochondrial oxidative function in human saponin-skinned muscle fibres: effects of prolonged exercise.

Document identifier: oai:dalea.du.se:2328
Publication year: 1998
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Abstract:

1. The influence of prolonged exhaustive exercise on mitochondrial oxidative function was investigated in ten men. 2. Muscle biopsies were taken before and after exercise and mitochondrial respiration investigated in fibre bundles made permeable by pretreatment with saponin. 3. After exercise, respiration in the absence of ADP increased by 18 % (P< 0.01), but respiration at suboptimal ADP concentration (0.1 mM) and maximal ADP-stimulated respiration (1 mM ADP) remained unchanged. 4. In the presence of creatine (20 mM), mitochondrial affinity for ADP increased markedly and respiration at suboptimal ADP concentration (0.1 mM) was similar (pre-exercise) or higher (post-exercise; P< 0.05) than with 1 mM ADP alone. The increase in respiratory rate with creatine was correlated to the relative type I fibre area (r = 0.84). Creatine-stimulated respiration increased after prolonged exercise (P< 0.01). 5. The respiratory control index (6.8 ± 0.4, mean ± s.e.m.) and the ratio between respiration at 0.1 and 1 mM ADP (ADP sensitivity index, 0.63 ± 0.03) were not changed after exercise. The sensitivity index was negatively correlated to the relative type I fibre area (r = -0.86). 6. The influence of exercise on muscle oxidative function has for the first time been investigated with the skinned-fibre technique. It is concluded that maximal mitochondrial oxidative power is intact or improved after prolonged exercise, while uncoupled respiration is increased. The latter finding may contribute to the elevated post-exercise oxygen consumption. The finding that the sensitivity of mitochondrial respiration for ADP and creatine are related to fibre-type composition indicates intrinsic differences in the control of mitochondrial respiration between fibres.

Authors

Michail Tonkonogi

Högskolan Dalarna; Medicinsk vetenskap
Other publications >>

Bearn Harris

Other publications >>

Kent Sahlin

Other publications >>

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        identifier: oai:dalea.du.se:2328
        datestamp: 2021-04-15T13:11:45Z
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                recordCreationDate: 2006-10-02
            identifier: http://urn.kb.se/resolve?urn=urn:nbn:se:du-2328
            titleInfo: 
                @attributes: 
                    lang: eng
                title: Mitochondrial oxidative function in human saponin-skinned muscle fibres: effects of prolonged exercise.
            abstract: 
1. \t\n\nThe influence of prolonged exhaustive exercise on mitochondrial oxidative function was investigated in ten men.\n2. \t\n\nMuscle biopsies were taken before and after exercise and mitochondrial respiration investigated in fibre bundles made permeable by pretreatment with saponin.\n3. \t\n\nAfter exercise respiration in the absence of ADP increased by 18 % (P< 0.01) but respiration at suboptimal ADP concentration (0.1 mM) and maximal ADP-stimulated respiration (1 mM ADP) remained unchanged.\n4. \t\n\nIn the presence of creatine (20 mM) mitochondrial affinity for ADP increased markedly and respiration at suboptimal ADP concentration (0.1 mM) was similar (pre-exercise) or higher (post-exercise; P< 0.05) than with 1 mM ADP alone. The increase in respiratory rate with creatine was correlated to the relative type I fibre area (r = 0.84). Creatine-stimulated respiration increased after prolonged exercise (P< 0.01).\n5. \t\n\nThe respiratory control index (6.8 ± 0.4 mean ± s.e.m.) and the ratio between respiration at 0.1 and 1 mM ADP (ADP sensitivity index 0.63 ± 0.03) were not changed after exercise. The sensitivity index was negatively correlated to the relative type I fibre area (r = -0.86).\n6. \t\n\nThe influence of exercise on muscle oxidative function has for the first time been investigated with the skinned-fibre technique. It is concluded that maximal mitochondrial oxidative power is intact or improved after prolonged exercise while uncoupled respiration is increased. The latter finding may contribute to the elevated post-exercise oxygen consumption. The finding that the sensitivity of mitochondrial respiration for ADP and creatine are related to fibre-type composition indicates intrinsic differences in the control of mitochondrial respiration between fibres.

            language: 
                languageTerm: eng
            genre: 
                publication/journal-article
                ref
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                Published
                3
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                        type: personal
                        authority: du
                    namePart: 
                        Tonkonogi
                        Michail
                    role: 
                        roleTerm: aut
                    affiliation: 
                        Högskolan Dalarna
                        Medicinsk vetenskap
                    nameIdentifier: 
                        mtn
                        0000-0003-1619-9758
                    @attributes: 
                        type: personal
                    namePart: 
                        Harris
                        Bearn
                    role: 
                        roleTerm: aut
                    @attributes: 
                        type: personal
                    namePart: 
                        Sahlin
                        Kent
                    role: 
                        roleTerm: aut
            originInfo: 
                dateIssued: 1998
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                    type: host
                titleInfo: 
                    title: Journal of Physiology
                identifier: 
                    0022-3751
                    1469-7793
                part: 
                    detail: 
                        @attributes: 
                            type: volume
                        number: 510
                    extent: 
                        start: 279
                        end: 286
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                form: print
            typeOfResource: text