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Tallis J, James RS, Eyre ELJ, Shelley SP, Hill C, Renshaw D, Hurst J. Effect of high-fat diet on isometric, concentric and eccentric contractile performance of skeletal muscle isolated from female CD-1 mice. Exp Physiol 2024; 109:1163-1176. [PMID: 38723238 PMCID: PMC11215475 DOI: 10.1113/ep091832] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2024] [Accepted: 04/25/2024] [Indexed: 07/02/2024]
Abstract
Despite evidence inferring muscle and contractile mode-specific effects of high-fat diet (HFD), no study has yet considered the impact of HFD directly on eccentric muscle function. The present work uniquely examined the effect of 20-week HFD on the isometric, concentric and eccentric muscle function of isolated mouse soleus (SOL) and extensor digitorum longus (EDL) muscles. CD-1 female mice were randomly split into a control (n = 16) or HFD (n = 17) group and for 20 weeks consumed standard lab chow or HFD. Following this period, SOL and EDL muscles were isolated and assessments of maximal isometric force and concentric work loop (WL) power were performed. Each muscle was then subjected to either multiple concentric or eccentric WL activations. Post-fatigue recovery, as an indicator of incurred damage, was measured via assessment of concentric WL power. In the EDL, absolute concentric power and concentric power normalised to muscle mass were reduced in the HFD group (P < 0.038). HFD resulted in faster concentric fatigue and reduced eccentric activity-induced muscle damage (P < 0.05). For the SOL, maximal isometric force was increased, and maximal eccentric power normalised to muscle mass and concentric fatigue were reduced in the HFD group (P < 0.05). HFD effects on eccentric muscle function are muscle-specific and have little relationship with changes in isometric or concentric function. HFD has the potential to negatively affect the intrinsic concentric and eccentric power-producing capacity of skeletal muscle, but a lack of a within-muscle uniform response indicates disparate mechanisms of action which require further investigation.
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Affiliation(s)
- Jason Tallis
- Centre for Physical Activity, Sport & Exercise ScienceCoventry UniversityCoventryUK
| | - Rob S. James
- Faculty of Life SciencesUniversity of BradfordBradfordUK
| | - Emma L. J. Eyre
- Centre for Physical Activity, Sport & Exercise ScienceCoventry UniversityCoventryUK
| | - Sharn P. Shelley
- Centre for Physical Activity, Sport & Exercise ScienceCoventry UniversityCoventryUK
| | - Cameron Hill
- Randall Centre for Cell and Molecular Biophysics, New Hunt's House, Guy's CampusKing's College LondonLondonUK
| | - Derek Renshaw
- Centre for Health & Life SciencesCoventry UniversityCoventryUK
| | - Josh Hurst
- Centre for Physical Activity, Sport & Exercise ScienceCoventry UniversityCoventryUK
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2
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Kano R, Tabuchi A, Tanaka Y, Shirakawa H, Hoshino D, Poole DC, Kano Y. In vivo cytosolic H 2O 2 changes and Ca 2+ homeostasis in mouse skeletal muscle. Am J Physiol Regul Integr Comp Physiol 2024; 326:R43-R52. [PMID: 37899753 DOI: 10.1152/ajpregu.00152.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2023] [Revised: 09/21/2023] [Accepted: 10/20/2023] [Indexed: 10/31/2023]
Abstract
Hydrogen peroxide (H2O2) and calcium ions (Ca2+) are functional regulators of skeletal muscle contraction and metabolism. Although H2O2 is one of the activators of the type-1 ryanodine receptor (RyR1) in the Ca2+ release channel, the interdependence between H2O2 and Ca2+ dynamics remains unclear. This study tested the following hypotheses using an in vivo model of mouse tibialis anterior (TA) skeletal muscle. 1) Under resting conditions, elevated cytosolic H2O2 concentration ([H2O2]cyto) leads to a concentration-dependent increase in cytosolic Ca2+ concentration ([Ca2+]cyto) through its effect on RyR1; and 2) in hypoxia (cardiac arrest) and muscle contractions (electrical stimulation), increased [H2O2]cyto induces Ca2+ accumulation. Cytosolic H2O2 (HyPer7) and Ca2+ (Fura-2) dynamics were resolved by TA bioimaging in young C57BL/6J male mice under four conditions: 1) elevated exogenous H2O2; 2) cardiac arrest; 3) twitch (1 Hz, 60 s) contractions; and 4) tetanic (30 s) contractions. Exogenous H2O2 (0.1-100 mM) induced a concentration-dependent increase in [H2O2]cyto (+55% at 0.1 mM; +280% at 100 mM) and an increase in [Ca2+]cyto (+3% at 1.0 mM; +8% at 10 mM). This increase in [Ca2+]cyto was inhibited by pharmacological inhibition of RyR1 by dantrolene. Cardiac arrest-induced hypoxia increased [H2O2]cyto (+33%) and [Ca2+]cyto (+20%) 50 min postcardiac arrest. Compared with the exogenous 1.0 mM H2O2 condition, [H2O2]cyto after tetanic muscle contractions rose less than one-tenth as much, whereas [Ca2+]cyto was 4.7-fold higher. In conclusion, substantial increases in [H2O2]cyto levels evoke only modest Ca2+ accumulation via their effect on the sarcoplasmic reticulum RyR1. On the other hand, contrary to hypoxia secondary to cardiac arrest, increases in [H2O2]cyto from muscle contractions are small, indicating that H2O2 generation is unlikely to be a primary factor driving the significant Ca2+ accumulation after, especially tetanic, muscle contractions.NEW & NOTEWORTHY We developed an in vivo mouse myocyte H2O2 imaging model during exogenous H2O2 loading, ischemic hypoxia induced by cardiac arrest, and muscle contractions. In this study, the interrelationship between cytosolic H2O2 levels and Ca2+ homeostasis during muscle contraction and hypoxic conditions was revealed. These results contribute to the elucidation of the mechanisms of muscle fatigue and exercise adaptation.
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Affiliation(s)
- Ryotaro Kano
- Department of Engineering Science, Bioscience and Technology Program, University of Electro-Communications, Chofu, Japan
- Research Fellowship for Young Scientists, Japan Society for the Promotion of Science, Tokyo, Japan
| | - Ayaka Tabuchi
- Department of Engineering Science, Bioscience and Technology Program, University of Electro-Communications, Chofu, Japan
| | - Yoshinori Tanaka
- Department of Engineering Science, Bioscience and Technology Program, University of Electro-Communications, Chofu, Japan
| | - Hideki Shirakawa
- Department of Engineering Science, Bioscience and Technology Program, University of Electro-Communications, Chofu, Japan
| | - Daisuke Hoshino
- Department of Engineering Science, Bioscience and Technology Program, University of Electro-Communications, Chofu, Japan
- Center for Neuroscience and Biomedical Engineering, University of Electro-Communications, Chofu, Japan
| | - David C Poole
- Departments of Anatomy and Physiology and Kinesiology, Kansas State University, Manhattan, Kansas, United States
| | - Yutaka Kano
- Department of Engineering Science, Bioscience and Technology Program, University of Electro-Communications, Chofu, Japan
- Center for Neuroscience and Biomedical Engineering, University of Electro-Communications, Chofu, Japan
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3
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Mandal M, Banik D, Karak A, Manna SK, Mahapatra AK. Spiropyran-Merocyanine Based Photochromic Fluorescent Probes: Design, Synthesis, and Applications. ACS OMEGA 2022; 7:36988-37007. [PMID: 36312341 PMCID: PMC9608402 DOI: 10.1021/acsomega.2c04969] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/04/2022] [Accepted: 09/26/2022] [Indexed: 05/27/2023]
Abstract
Due to ever-increasing insights into their fundamental properties and photochromic behaviors, spiropyran derivatives are still a target of interest for researchers. The interswitching ability of this photochrome between the spiropyran (SP) and merocyanine (MC) isoforms under external stimuli (light, cations, anions, pH etc.) with different spectral properties as well as the protonation-deprotonation of its MC form allows researchers to use it suitably in sensing purposes by developing different colorimetric and fluorometric probes. Selective and sensitive recognition can be achieved by little modification of its SP moiety and functional groups. In this review, we emphasize the recent advancements (from 2019 to 2022) of spiropyran-merocyanine based fluorogenic and chromogenic probes for selective detection of various metal ions, anions, neutral analytes, and pH. We precisely explain their design strategies, sensing mechanisms, and biological and environmental applications. This review may accelerate the improvements in designing more advanced probes with innovative applications in the near future.
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Affiliation(s)
- Moumi Mandal
- Department
of Chemistry, Indian Institute of Engineering
Science and Technology, Shibpur, Howrah 711103, West Bengal, India
| | - Dipanjan Banik
- Department
of Chemistry, Indian Institute of Engineering
Science and Technology, Shibpur, Howrah 711103, West Bengal, India
| | - Anirban Karak
- Department
of Chemistry, Indian Institute of Engineering
Science and Technology, Shibpur, Howrah 711103, West Bengal, India
| | - Saikat Kumar Manna
- Department
of Chemistry, Haldia Government College, Debhog, Haldia, Purba Medinipur 721657, West Bengal, India
| | - Ajit Kumar Mahapatra
- Department
of Chemistry, Indian Institute of Engineering
Science and Technology, Shibpur, Howrah 711103, West Bengal, India
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4
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Nogueira L, Gilmore NK, Hogan MC. Role of parvalbumin in fatigue-induced changes in force and cytosolic calcium transients in intact single mouse myofibers. J Appl Physiol (1985) 2022; 132:1041-1053. [PMID: 35238653 PMCID: PMC8993520 DOI: 10.1152/japplphysiol.00861.2021] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
One of the most important cytosolic Ca2+ buffers present in mouse fast-twitch myofibers, but not in human myofibers, is parvalbumin (PV). Previous work using conventional PV knockout mice suggests that lifelong PV ablation increases fatigue resistance, possibly due to compensations in mitochondrial volume. In this work, PV gene ablation was induced only in adult mice (PV-KO), and contractile and cytosolic Ca2+ responses during fatigue were studied in isolated muscle and intact single myofibers. Results were compared to control littermates (PV-Ctr). We hypothesized that the reduced myofiber cytosolic Ca2+ buffering developed only in adult PV-KO mice leads to a larger cytosolic free Ca2+ concentration ([Ca2+]c) during repetitive contractions, increasing myofiber fatigue resistance. Extensor digitorum longus (EDL) muscles from PV-KO mice had higher force in unfused stimulations (~50%, P<0.05) and slowed relaxation (~46% higher relaxation time, P<0.05) vs PV-Ctr, but muscle fatigue resistance or fatigue-induced changes in relaxation were not different between genotypes (P>0.05). In intact single myofibers from flexor digitorum brevis (FDB) muscles, basal and tetanic [Ca2+]c during fatiguing contractions were higher in PV-KO (P<0.05), accompanied by a greater slowing in estimated sarcoplasmic reticulum (SR) Ca2+ pumping vs PV-Ctr myofibers (~84% reduction, P<0.05), but myofiber fatigue resistance was not different between genotypes (P>0.05). Our results demonstrate that although the estimated SR Ca2+ uptake was accelerated in PV-KO, the total energy demand by the major energy consumers in myofibers, the cross-bridges and SR Ca2+ ATPase, were not altered enough to affect the energy supply for contractions, and therefore fatigue resistance remained unaffected.
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Affiliation(s)
- Leonardo Nogueira
- Section of Physiology; Division of Pulmonary, Critical Care and Sleep Medicine; Department of Medicine, University of California San Diego, La Jolla, California, United States
| | - Natalie K Gilmore
- Section of Physiology; Division of Pulmonary, Critical Care and Sleep Medicine; Department of Medicine, University of California San Diego, La Jolla, California, United States
| | - Michael C Hogan
- Section of Physiology; Division of Pulmonary, Critical Care and Sleep Medicine; Department of Medicine, University of California San Diego, La Jolla, California, United States
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5
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Banik D, Manna SK, Maiti A, Mahapatra AK. Recent Advancements in Colorimetric and Fluorescent pH Chemosensors: From Design Principles to Applications. Crit Rev Anal Chem 2022; 53:1313-1373. [PMID: 35086371 DOI: 10.1080/10408347.2021.2023002] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/24/2023]
Abstract
Due to the immense biological significance of pH in diverse living systems, the design, synthesis, and development of pH chemosensors for pH monitoring has been a very active research field in recent times. In this review, we summarize the designing strategies, sensing mechanisms, biological and environmental applications of fluorogenic and chromogenic pH chemosensors of the last three years (2018-2020). We categorized these pH probes into seven types based on their applications, including 1) Cancer cell discriminating pH probes; 2) Lysosome targetable pH probes; 3) Mitochondria targetable pH probes; 4) Golgi body targetable pH probes; 5) Endoplasmic reticulum targetable pH probes; 6) pH probes used in nonspecific cell imaging; and 7) pH probes without cell imaging. All these different categories exhibit diverse applications of pH probes in biological and environmental fields.
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Affiliation(s)
- Dipanjan Banik
- Department of Chemistry, Indian Institute of Engineering Science and Technology, Shibpur, Howrah, West Bengal, India
| | - Saikat Kumar Manna
- Department of Chemistry, Haldia Government College, Purba Medinipur, West Bengal, India
| | - Anwesha Maiti
- Department of Chemistry, Indian Institute of Engineering Science and Technology, Shibpur, Howrah, West Bengal, India
| | - Ajit Kumar Mahapatra
- Department of Chemistry, Indian Institute of Engineering Science and Technology, Shibpur, Howrah, West Bengal, India
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6
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Hostrup M, Cairns SP, Bangsbo J. Muscle Ionic Shifts During Exercise: Implications for Fatigue and Exercise Performance. Compr Physiol 2021; 11:1895-1959. [PMID: 34190344 DOI: 10.1002/cphy.c190024] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Exercise causes major shifts in multiple ions (e.g., K+ , Na+ , H+ , lactate- , Ca2+ , and Cl- ) during muscle activity that contributes to development of muscle fatigue. Sarcolemmal processes can be impaired by the trans-sarcolemmal rundown of ion gradients for K+ , Na+ , and Ca2+ during fatiguing exercise, while changes in gradients for Cl- and Cl- conductance may exert either protective or detrimental effects on fatigue. Myocellular H+ accumulation may also contribute to fatigue development by lowering glycolytic rate and has been shown to act synergistically with inorganic phosphate (Pi) to compromise cross-bridge function. In addition, sarcoplasmic reticulum Ca2+ release function is severely affected by fatiguing exercise. Skeletal muscle has a multitude of ion transport systems that counter exercise-related ionic shifts of which the Na+ /K+ -ATPase is of major importance. Metabolic perturbations occurring during exercise can exacerbate trans-sarcolemmal ionic shifts, in particular for K+ and Cl- , respectively via metabolic regulation of the ATP-sensitive K+ channel (KATP ) and the chloride channel isoform 1 (ClC-1). Ion transport systems are highly adaptable to exercise training resulting in an enhanced ability to counter ionic disturbances to delay fatigue and improve exercise performance. In this article, we discuss (i) the ionic shifts occurring during exercise, (ii) the role of ion transport systems in skeletal muscle for ionic regulation, (iii) how ionic disturbances affect sarcolemmal processes and muscle fatigue, (iv) how metabolic perturbations exacerbate ionic shifts during exercise, and (v) how pharmacological manipulation and exercise training regulate ion transport systems to influence exercise performance in humans. © 2021 American Physiological Society. Compr Physiol 11:1895-1959, 2021.
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Affiliation(s)
- Morten Hostrup
- Section of Integrative Physiology, Department of Nutrition, Exercise and Sports, University of Copenhagen, Copenhagen, Denmark
| | - Simeon Peter Cairns
- SPRINZ, School of Sport and Recreation, Auckland University of Technology, Auckland, New Zealand.,Health and Rehabilitation Research Institute, Auckland University of Technology, Auckland, New Zealand
| | - Jens Bangsbo
- Section of Integrative Physiology, Department of Nutrition, Exercise and Sports, University of Copenhagen, Copenhagen, Denmark
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7
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Tobiansky DJ, Miles MC, Goller F, Fuxjager MJ. Androgenic modulation of extraordinary muscle speed creates a performance trade-off with endurance. J Exp Biol 2020; 223:jeb222984. [PMID: 32291320 DOI: 10.1242/jeb.222984] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2020] [Accepted: 04/04/2020] [Indexed: 12/30/2022]
Abstract
Performance trade-offs can dramatically alter an organism's evolutionary trajectory by making certain phenotypic outcomes unattainable. Understanding how these trade-offs arise from an animal's design is therefore an important goal of biology. To explore this topic, we studied how androgenic hormones, which regulate skeletal muscle function, influence performance trade-offs relevant to different components of complex reproductive behaviour. We conducted this work in golden-collared manakins (Manacus vitellinus), a neotropical bird in which males court females by rapidly snapping their wings together above their back. Androgens help mediate this behavior by radically increasing the twitch speed of a dorsal wing muscle (scapulohumeralis caudalis, SH), which actuates the bird's wing-snap. Through hormone manipulations and in situ muscle recordings, we tested how these positive effects on SH speed influence trade-offs with endurance. Indeed, this latter trait impacts the display by shaping signal length. We found that androgen-dependent increases in SH speed incur a cost to endurance, particularly when this muscle performs at its functional limits. Moreover, when behavioural data were overlaid on our muscle recordings, displaying animals appeared to balance display speed with fatigue-induced muscle fusion (physiological tetanus) to generate the fastest possible signal while maintaining an appropriate signal duration. Our results point to androgen action as a functional trigger of trade-offs in sexual performance - these hormones enhance one element of a courtship display, but in doing so, impede another.
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Affiliation(s)
- Daniel J Tobiansky
- Department of Ecology and Evolutionary Biology, Brown University, Providence, RI 02912, USA
| | - Meredith C Miles
- Department of Ecology and Evolutionary Biology, Brown University, Providence, RI 02912, USA
| | - Franz Goller
- Department of Biology, The University of Utah, Salt Lake City, UT 84112, USA
- Institute for Zoophysiology, University of Münster, 48149 Münster, Germany
| | - Matthew J Fuxjager
- Department of Ecology and Evolutionary Biology, Brown University, Providence, RI 02912, USA
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8
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Benitez-Martin C, Guadix JA, Pearson JR, Najera F, Perez-Pomares JM, Perez-Inestrosa E. Indolenine-Based Derivatives as Customizable Two-Photon Fluorescent Probes for pH Bioimaging in Living Cells. ACS Sens 2020; 5:1068-1074. [PMID: 32227860 DOI: 10.1021/acssensors.9b02590] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Novel pH probes based on 2-(6-methoxynaphthalen-2-yl)-3,3-dimethyl-3H-indole have been synthesized and characterized. These compounds display excellent "off-on" fluorescence responses to acidic pH especially under two-photon (TP) excitation conditions as well as strong selectivity and sensitivity toward H+. These features are supported by fluorescence quantum yields over 35%, TP cross sections ∼60 GM, and good resistance to photodegradation under acidic conditions. The synthetic versatility of this model allows subcellular targets to be tuned through minor scaffold modifications without affecting its optical characteristics. The effectiveness of the probes' innate photophysical properties and the structural modifications for different pH-related applications are demonstrated in mouse embryonic fibroblast cells.
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Affiliation(s)
- Carlos Benitez-Martin
- Departamento de Quı́mica Orgánica, Universidad de Málaga-IBIMA, Campus de Teatinos s/n, Málaga 29071, Spain
- Centro Andaluz de Nanomedicina y Biotecnologı́a-BIONAND, Parque Tecnológico de Andalucía, c/Severo Ochoa, 35, 29590 Campanillas, Málaga 29071, Spain
| | - Juan A. Guadix
- Departamento de Biologı́a Animal, Facultad de Ciencias, Universidad de Málaga-IBIMA, Campus de Teatinos s/n, Málaga 29071, Spain
- Centro Andaluz de Nanomedicina y Biotecnologı́a-BIONAND, Parque Tecnológico de Andalucía, c/Severo Ochoa, 35, 29590 Campanillas, Málaga 29071, Spain
| | - John R. Pearson
- Centro Andaluz de Nanomedicina y Biotecnologı́a-BIONAND, Parque Tecnológico de Andalucía, c/Severo Ochoa, 35, 29590 Campanillas, Málaga 29071, Spain
| | - Francisco Najera
- Departamento de Quı́mica Orgánica, Universidad de Málaga-IBIMA, Campus de Teatinos s/n, Málaga 29071, Spain
- Centro Andaluz de Nanomedicina y Biotecnologı́a-BIONAND, Parque Tecnológico de Andalucía, c/Severo Ochoa, 35, 29590 Campanillas, Málaga 29071, Spain
| | - Jose M. Perez-Pomares
- Departamento de Biologı́a Animal, Facultad de Ciencias, Universidad de Málaga-IBIMA, Campus de Teatinos s/n, Málaga 29071, Spain
- Centro Andaluz de Nanomedicina y Biotecnologı́a-BIONAND, Parque Tecnológico de Andalucía, c/Severo Ochoa, 35, 29590 Campanillas, Málaga 29071, Spain
| | - Ezequiel Perez-Inestrosa
- Departamento de Quı́mica Orgánica, Universidad de Málaga-IBIMA, Campus de Teatinos s/n, Málaga 29071, Spain
- Centro Andaluz de Nanomedicina y Biotecnologı́a-BIONAND, Parque Tecnológico de Andalucía, c/Severo Ochoa, 35, 29590 Campanillas, Málaga 29071, Spain
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9
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Bartlett MF, Fitzgerald LF, Nagarajan R, Hiroi Y, Kent JA. Oxidative ATP synthesis in human quadriceps declines during 4 minutes of maximal contractions. J Physiol 2020; 598:1847-1863. [PMID: 32045011 DOI: 10.1113/jp279339] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2019] [Accepted: 01/30/2020] [Indexed: 12/16/2022] Open
Abstract
KEY POINTS During maximal exercise, skeletal muscle metabolism and oxygen consumption remain elevated despite precipitous declines in power. Presently, it is unclear whether these responses are caused by an increased ATP cost of force generation (ATPCOST ) or mitochondrial uncoupling; a process that reduces the efficiency of oxidative ATP synthesis (ATPOX ). To address this gap, we used 31-phosphorus magnetic resonance spectroscopy to measure changes in ATPCOST and ATPOX in human quadriceps during repeated trials of maximal intensity knee extensions lasting up to 4 min. ATPCOST remained unchanged. In contrast, ATPOX plateaued by ∼2 min and then declined (∼15%) over the final 2 min. The maximal capacity for ATPOX (Vmax ), as well as ADP-specific rates of ATPOX , were also significantly diminished. Collectively, these results suggest that mitochondrial uncoupling, and not increased ATPCOST , is responsible for altering the regulation of skeletal muscle metabolism and oxygen consumption during maximal exercise. ABSTRACT The relationship between skeletal muscle oxygen consumption and power output is augmented during exercise at workloads above the lactate threshold. Potential mechanisms for this response have been hypothesized, including increased ATP cost of force generation (ATPCOST ) and mitochondrial uncoupling, a process that reduces the efficiency of oxidative ATP synthesis (ATPOX ). To test these hypotheses, we used phosphorus magnetic resonance spectroscopy to non-invasively measure changes in phosphate concentrations and pH in the vastus lateralis muscle of nine young adults during repeated trials of maximal, all-out dynamic knee extensions (120°s-1 , 1 every 2 s) lasting 24, 60, 120, and 240 s. ATPOX was measured at each time point from the initial velocity of PCr resynthesis, and ATPCOST was calculated as the sum of ATP synthesized by the creatine and adenylate kinase reactions, non-oxidative glycolysis, ATPOX and net changes in [ATP]. Power output declined in a reproducible manner for all four trials. ATPCOST did not change over time (main effect P = 0.45). ATPOX plateaued from 60 to 120 s and then decreased over the final 120 s (main effect P = 0.001). The maximal capacity for oxidative ATP synthesis (Vmax ), as well as ADP-specific rates of ATPOX , also decreased over time (main effect P = 0.001, both). Collectively, these results demonstrate that prolonged maximal contraction protocols impair oxidative energetics and implicate mitochondrial uncoupling as the mechanism for this response. The causes of mitochondrial uncoupling are presently unknown but may offer a potential explanation for the dissociation between skeletal muscle power output and oxygen consumption during maximal, all-out exercise protocols.
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Affiliation(s)
- Miles F Bartlett
- Muscle Physiology Laboratory, Department of Kinesiology, University of Massachusetts, Amherst, Massachusetts, 01003.,Department of Kinesiology, University of Texas, Arlington, Texas, 76019
| | - Liam F Fitzgerald
- Muscle Physiology Laboratory, Department of Kinesiology, University of Massachusetts, Amherst, Massachusetts, 01003
| | - Rajakumar Nagarajan
- Human Magnetic Resonance Center, Institute for Applied Life Sciences (IALS), University of Massachusetts, Amherst, Massachusetts, 01003
| | - Yeun Hiroi
- Muscle Physiology Laboratory, Department of Kinesiology, University of Massachusetts, Amherst, Massachusetts, 01003
| | - Jane A Kent
- Muscle Physiology Laboratory, Department of Kinesiology, University of Massachusetts, Amherst, Massachusetts, 01003
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10
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Bailey SJ, Gandra PG, Jones AM, Hogan MC, Nogueira L. Incubation with sodium nitrite attenuates fatigue development in intact single mouse fibres at physiological P O 2 . J Physiol 2019; 597:5429-5443. [PMID: 31541562 DOI: 10.1113/jp278494] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2019] [Accepted: 09/20/2019] [Indexed: 12/22/2022] Open
Abstract
KEY POINTS Dietary nitrate supplementation increases plasma nitrite concentration, which provides an oxygen-independent source of nitric oxide and can delay skeletal muscle fatigue. Nitrate supplementation has been shown to increase myofibre calcium release and force production in mouse skeletal muscle during contractions at a supra-physiological oxygen tension, but it is unclear whether nitrite exposure can delay fatigue development and improve myofibre calcium handling at a near-physiological oxygen tension. Single mouse muscle fibres acutely treated with nitrite had a lower force and cytosolic calcium concentration during single non-fatiguing contractions at a near-physiological oxygen tension. Nitrite treatment delayed fatigue development during repeated fatiguing isometric contractions at near-physiological, but not at supra-physiological, oxygen tension in combination with better maintenance of myofilament calcium sensitivity and sarcoplasmic reticulum calcium pumping. These findings improve understanding of the mechanisms by which increased skeletal muscle nitrite exposure might be ergogenic and imply that this is related to improved calcium handling. ABSTRACT Dietary nitrate (NO3 - ) supplementation, which increases plasma nitrite (NO2 - ) concentration, has been reported to attenuate skeletal muscle fatigue development. Sarcoplasmic reticulum (SR) calcium (Ca2+ ) release is enhanced in isolated single skeletal muscle fibres following NO3 - supplementation or NO2 - incubation at a supra-physiological P O 2 but it is unclear whether NO2 - incubation can alter Ca2+ handling and fatigue development at a near-physiological P O 2 . We hypothesised that NO2 - treatment would improve Ca2+ handling and delay fatigue at a physiological P O 2 in intact single mouse skeletal muscle fibres. Each muscle fibre was perfused with Tyrode solution pre-equilibrated with either 20% ( P O 2 ∼150 Torr) or 2% O2 ( P O 2 = 15.6 Torr) in the absence and presence of 100 µM NaNO2 . At supra-physiological P O 2 (i.e. 20% O2 ), time to fatigue was lowered by 34% with NaNO2 (control: 257 ± 94 vs. NaNO2 : 159 ± 46 s, Cohen's d = 1.63, P < 0.05), but extended by 21% with NaNO2 at 2% O2 (control: 308 ± 217 vs. NaNO2 : 368 ± 242 s, d = 1.14, P < 0.01). During the fatiguing contraction protocol completed with NaNO2 at 2% O2 , peak cytosolic Ca2+ concentration ([Ca2+ ]c ) was not different (P > 0.05) but [Ca2+ ]c accumulation between contractions was lower, concomitant with a greater SR Ca2+ pumping rate (P < 0.05) compared to the control condition. These results demonstrate that increased exposure to NO2 - blunts fatigue development at near-physiological, but not at supra-physiological, P O 2 through enhancing SR Ca2+ pumping rate in single skeletal muscle fibres. These findings extend our understanding of the mechanisms by which increased NO2 - exposure can mitigate skeletal muscle fatigue development.
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Affiliation(s)
- Stephen J Bailey
- Sport and Health Sciences, College of Life and Environmental Sciences, University of Exeter, Exeter, UK.,School of Sport, Exercise and Health Sciences, Loughborough University, Loughborough, UK
| | - Paulo G Gandra
- Section of Physiology; Division of Pulmonary, Critical Care & Sleep Medicine, Department of Medicine, University of California, San Diego, CA, USA.,Department of Biochemistry and Tissue Biology, Institute of Biology, University of Campinas (Unicamp), Campinas, Brazil
| | - Andrew M Jones
- Sport and Health Sciences, College of Life and Environmental Sciences, University of Exeter, Exeter, UK
| | - Michael C Hogan
- Section of Physiology; Division of Pulmonary, Critical Care & Sleep Medicine, Department of Medicine, University of California, San Diego, CA, USA
| | - Leonardo Nogueira
- Section of Physiology; Division of Pulmonary, Critical Care & Sleep Medicine, Department of Medicine, University of California, San Diego, CA, USA.,Instituto de Bioquímica Médica Leopoldo de Meis (Medical Biochemistry Institute Leopoldo de Meis), Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
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11
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Monitoring Exercise-Induced Muscle Fatigue and Adaptations: Making Sense of Popular or Emerging Indices and Biomarkers. Sports (Basel) 2018; 6:sports6040153. [PMID: 30486243 PMCID: PMC6315493 DOI: 10.3390/sports6040153] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2018] [Revised: 11/17/2018] [Accepted: 11/21/2018] [Indexed: 11/17/2022] Open
Abstract
Regular exercise with the appropriate intensity and duration may improve an athlete’s physical capacities by targeting different performance determinants across the endurance–strength spectrum aiming to delay fatigue. The mechanisms of muscle fatigue depend on exercise intensity and duration and may range from substrate depletion to acidosis and product inhibition of adenosinetriphosphatase (ATPase) and glycolysis. Fatigue mechanisms have been studied in isolated muscles; single muscle fibers (intact or skinned) or at the level of filamentous or isolated motor proteins; with each approach contributing to our understanding of the fatigue phenomenon. In vivo methods for monitoring fatigue include the assessment of various functional indices supported by the use of biochemical markers including blood lactate levels and more recently redox markers. Blood lactate measurements; as an accompaniment of functional assessment; are extensively used for estimating the contribution of the anaerobic metabolism to energy expenditure and to help interpret an athlete’s resistance to fatigue during high intensity exercise. Monitoring of redox indices is gaining popularity in the applied sports performance setting; as oxidative stress is not only a fatigue agent which may play a role in the pathophysiology of overtraining syndrome; but also constitutes an important signaling pathway for training adaptations; thus reflecting training status. Careful planning of sampling and interpretation of blood biomarkers should be applied; especially given that their levels can fluctuate according to an athlete’s lifestyle and training histories.
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12
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Nogueira L, Trisko BM, Lima‐Rosa FL, Jackson J, Lund‐Palau H, Yamaguchi M, Breen EC. Cigarette smoke directly impairs skeletal muscle function through capillary regression and altered myofibre calcium kinetics in mice. J Physiol 2018; 596:2901-2916. [PMID: 29797443 PMCID: PMC6046067 DOI: 10.1113/jp275888] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2018] [Accepted: 04/18/2018] [Indexed: 12/21/2022] Open
Abstract
KEY POINTS Cigarette smoke components directly alter muscle fatigue resistance and intracellular muscle fibre Ca2+ handling independent of a change in lung structure. Changes in muscle vascular structure are associated with a depletion of satellite cells. Sarcoplasmic reticulum Ca2+ uptake is substantially impaired in myofibres during fatiguing contractions in mice treated with cigarette smoke extract. ABSTRACT Cigarette smokers exhibit exercise intolerance before a decline in respiratory function. In the present study, the direct effects of cigarette smoke on limb muscle function were tested by comparing cigarette smoke delivered to mice by weekly injections of cigarette smoke extract (CSE), or nose-only exposure (CS) 5 days each week, for 8 weeks. Cigarette smoke delivered by either route did not alter pulmonary airspace size. Muscle fatigue measured in situ was 50% lower in the CSE and CS groups than in control. This was accompanied by 34% and 22% decreases in soleus capillary-to-fibre ratio of the CSE and CS groups, respectively, and a trend for fewer skeletal muscle actin-positive arterioles (P = 0.07). In addition, fewer quiescent satellite cells (Nes+Pax7+) were associated with soleus fibres in mice with skeletal myofibre VEGF gene deletion (decreased 47%) and CS exposed (decreased 73%) than with control fibres. Contractile properties of isolated extensor digitorum longus and soleus muscles were impaired. In flexor digitorum brevis myofibres isolated from CSE mice, fatigue resistance was diminished by 43% compared to control and CS myofibres, and this was accompanied by a pronounced slowing in relaxation, an increase in intracellular Ca2+ accumulation, and a slowing in sarcoplasmic reticulum Ca2+ uptake. These data suggest that cigarette smoke components may impair hindlimb muscle vascular structure, fatigue resistance and myofibre calcium handling, and these changes ultimately affect contractile efficiency of locomotor muscles independent of a change in lung function.
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Affiliation(s)
- Leonardo Nogueira
- Department of MedicineUniversity of California, San DiegoLa JollaCAUSA
- Instituto de Bioquímica Médica Leopoldo de Meis (IBqM‐LDM)Universidade Federal do Rio de JaneiroRio de JaneiroRJBrazil
| | - Breanna M. Trisko
- Department of MedicineUniversity of California, San DiegoLa JollaCAUSA
| | - Frederico L. Lima‐Rosa
- Instituto de Bioquímica Médica Leopoldo de Meis (IBqM‐LDM)Universidade Federal do Rio de JaneiroRio de JaneiroRJBrazil
| | - Jason Jackson
- Department of MedicineUniversity of California, San DiegoLa JollaCAUSA
| | - Helena Lund‐Palau
- Department of MedicineUniversity of California, San DiegoLa JollaCAUSA
| | - Masahiro Yamaguchi
- Department of Physiology, Kochi Medical SchoolKochi UniversityKochiJapan
| | - Ellen C. Breen
- Department of MedicineUniversity of California, San DiegoLa JollaCAUSA
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13
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Gandra PG, Shiah AA, Nogueira L, Hogan MC. A mitochondrial-targeted antioxidant improves myofilament Ca 2+ sensitivity during prolonged low frequency force depression at low PO2. J Physiol 2018; 596:1079-1089. [PMID: 29334129 DOI: 10.1113/jp275470] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2017] [Accepted: 01/08/2018] [Indexed: 12/22/2022] Open
Abstract
KEY POINTS Skeletal muscle contractile activity is associated with an enhanced reactive oxygen species (ROS) generation. At very low PO2, ROS generation by mitochondria can be elevated in intact cells. An elevated intracellular oxidant activity may affect muscle force development and recovery from fatigue. We treated intact single muscle fibres with a mitochondrial antioxidant and stimulated the fibres to contract at a low extracellular PO2 that is similar to the intracellular PO2 that is observed during moderate to intense exercise in vivo. The mitochondrial antioxidant prevented a sustained decrease in the myofibrillar Ca2+ sensitivity and improved muscle submaximal force development after fatigue at low extracellular PO2. ABSTRACT Skeletal muscle can develop a prolonged low frequency-stimulation force depression (PLFFD) following fatigue-inducing contractions. Increased levels of reactive oxygen species (ROS) have been implicated in the development of PLFFD. During exercise the skeletal muscle intracellular PO2 decreases to relatively low levels, and can be further decreased when there is an impairment in O2 diffusion or availability, such as in certain chronic diseases and during exercise at high altitude. Since ROS generation by mitochondria is elevated at very low PO2 in cells, we tested the hypothesis that treatment of muscle fibres with a mitochondrial-targeted antioxidant at a very low, near hypoxic, PO2 can attenuate PLFFD. We treated intact single fibres from mice with the mitochondrial-specific antioxidant SS31, and measured force development and intracellular [Ca2+ ] 30 min after fatigue at an extracellular PO2 of ∼5 Torr. After 30 min following the end of the fatiguing contractions, fibres treated with SS31 showed significantly less impairment in force development compared to untreated fibres at submaximal frequencies of stimulation. The cytosolic peak [Ca2+ ] transients (peak [Ca2+ ]c ) were equally decreased in both groups compared to pre-fatigue values. The combined force and peak [Ca2+ ]c data demonstrated that myofibrillar Ca2+ sensitivity was diminished in the untreated fibres 30 min after fatigue compared to pre-fatigue values, but Ca2+ sensitivity was unaltered in the SS31 treated fibres. These results demonstrate that at a very low PO2, treatment of skeletal muscle fibres with a mitochondrial antioxidant prevents a decrease in the myofibrillar Ca2+ sensitivity, which alleviates the fatigue induced PLFFD.
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Affiliation(s)
- Paulo G Gandra
- Department of Biochemistry and Tissue Biology, Institute of Biology, University of Campinas (Unicamp), Campinas, Brazil.,Department of Medicine, University of California San Diego, La Jolla, CA, USA
| | - Amy A Shiah
- Department of Medicine, University of California San Diego, La Jolla, CA, USA
| | - Leonardo Nogueira
- Institute of Medical Biochemistry Leopoldo de Meis, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil.,Department of Medicine, University of California San Diego, La Jolla, CA, USA
| | - Michael C Hogan
- Department of Medicine, University of California San Diego, La Jolla, CA, USA
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14
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Vieira JM, Gutierres JM, Carvalho FB, Pereira LB, Oliveira LS, Morsch VM, Schetinger MRC, Rodrigues MV, Leitemperger J, Loro V, Krewer CC, Vencato MS, Spanevello RM. Caffeine prevents changes in muscle caused by high-intensity interval training. Biomed Pharmacother 2017; 89:116-123. [DOI: 10.1016/j.biopha.2017.01.138] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2016] [Revised: 01/16/2017] [Accepted: 01/24/2017] [Indexed: 01/22/2023] Open
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15
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Jones RL, Barnett CT, Davidson J, Maritza B, Fraser WD, Harris R, Sale C. β-alanine supplementation improves in-vivo fresh and fatigued skeletal muscle relaxation speed. Eur J Appl Physiol 2017; 117:867-879. [PMID: 28349262 PMCID: PMC5388709 DOI: 10.1007/s00421-017-3569-1] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2016] [Accepted: 02/11/2017] [Indexed: 11/30/2022]
Abstract
Purpose In fresh muscle, supplementation with the rate-limiting precursor of carnosine, β-alanine (BA), results in a decline in muscle half-relaxation time (HRT) potentially via alterations to calcium (Ca2+) handling. Accumulation of hydrogen cation (H+) has been shown to impact Ca2+ signalling during muscular contraction, carnosine has the potential to serve as a cytoplasmic regulator of Ca2+ and H+ coupling, since it binds to both ions. The present study examined the effect of BA supplementation on intrinsic in-vivo isometric knee extensor force production and muscle contractility in both fresh and fatigued human skeletal muscle assessed during voluntary and electrically evoked (nerve and superficial muscle stimulation) contractions. Methods Twenty-three males completed two experimental sessions, pre- and post- 28 day supplementation with 6.4 g.day−1 of BA (n = 12) or placebo (PLA; n = 11). Isometric force was recorded during a series of voluntary and electrically evoked knee extensor contractions. Results BA supplementation had no effect on voluntary or electrically evoked isometric force production, or twitch electromechanical delay and time-to-peak tension. There was a significant decline in muscle HRT in fresh and fatigued muscle conditions during both resting (3 ± 13%; 19 ± 26%) and potentiated (1 ± 15%; 2 ± 20%) twitch contractions. Conclusions The mechanism for reduced HRT in fresh and fatigued skeletal muscle following BA supplementation is unclear. Due to the importance of muscle relaxation on total energy consumption, especially during short, repeated contractions, BA supplementation may prove to be beneficial in minimising contractile slowing induced by fatigue. Trial registration The trial is registered with Clinicaltrials.gov, ID number NCT02819505.
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Affiliation(s)
- Rebecca Louise Jones
- Musculoskeletal Physiology Research Group, Sport, Health and Performance Enhancement (SHAPE) Research Centre, School of Science and Technology, Nottingham Trent University, Erasmus Darwin Building, Clifton Lane, Clifton, Nottingham, NG11 8NS, UK
| | - Cleveland Thomas Barnett
- Musculoskeletal Physiology Research Group, Sport, Health and Performance Enhancement (SHAPE) Research Centre, School of Science and Technology, Nottingham Trent University, Erasmus Darwin Building, Clifton Lane, Clifton, Nottingham, NG11 8NS, UK
| | - Joel Davidson
- Musculoskeletal Physiology Research Group, Sport, Health and Performance Enhancement (SHAPE) Research Centre, School of Science and Technology, Nottingham Trent University, Erasmus Darwin Building, Clifton Lane, Clifton, Nottingham, NG11 8NS, UK
| | - Billy Maritza
- Musculoskeletal Physiology Research Group, Sport, Health and Performance Enhancement (SHAPE) Research Centre, School of Science and Technology, Nottingham Trent University, Erasmus Darwin Building, Clifton Lane, Clifton, Nottingham, NG11 8NS, UK
| | - William D Fraser
- Norwich Medical School, University of East Anglia, Norwich, Norfolk, UK
- Norfolk and Norwich University Hospital, Norwich, Norfolk, UK
| | | | - Craig Sale
- Musculoskeletal Physiology Research Group, Sport, Health and Performance Enhancement (SHAPE) Research Centre, School of Science and Technology, Nottingham Trent University, Erasmus Darwin Building, Clifton Lane, Clifton, Nottingham, NG11 8NS, UK.
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16
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Hostrup M, Bangsbo J. Limitations in intense exercise performance of athletes - effect of speed endurance training on ion handling and fatigue development. J Physiol 2016; 595:2897-2913. [PMID: 27673449 DOI: 10.1113/jp273218] [Citation(s) in RCA: 59] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2016] [Accepted: 09/21/2016] [Indexed: 01/10/2023] Open
Abstract
Mechanisms underlying fatigue development and limitations for performance during intense exercise have been intensively studied during the past couple of decades. Fatigue development may involve several interacting factors and depends on type of exercise undertaken and training level of the individual. Intense exercise (½-6 min) causes major ionic perturbations (Ca2+ , Cl- , H+ , K+ , lactate- and Na+ ) that may reduce sarcolemmal excitability, Ca2+ release and force production of skeletal muscle. Maintenance of ion homeostasis is thus essential to sustain force production and power output during intense exercise. Regular speed endurance training (SET), i.e. exercise performed at intensities above that corresponding to maximum oxygen consumption (V̇O2, max ), enhances intense exercise performance. However, most of the studies that have provided mechanistic insight into the beneficial effects of SET have been conducted in untrained and recreationally active individuals, making extrapolation towards athletes' performance difficult. Nevertheless, recent studies indicate that only a few weeks of SET enhances intense exercise performance in highly trained individuals. In these studies, the enhanced performance was not associated with changes in V̇O2, max and muscle oxidative capacity, but rather with adaptations in muscle ion handling, including lowered interstitial concentrations of K+ during and in recovery from intense exercise, improved lactate- -H+ transport and H+ regulation, and enhanced Ca2+ release function. The purpose of this Topical Review is to provide an overview of the effect of SET and to discuss potential mechanisms underlying enhancements in performance induced by SET in already well-trained individuals with special emphasis on ion handling in skeletal muscle.
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Affiliation(s)
- Morten Hostrup
- Section of Integrated Physiology, Department of Nutrition, Exercise and Sports, University of Copenhagen, Denmark.,Department of Respiratory Research, Bispebjerg University Hospital, Denmark
| | - Jens Bangsbo
- Section of Integrated Physiology, Department of Nutrition, Exercise and Sports, University of Copenhagen, Denmark
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Cè E, Rampichini S, Venturelli M, Limonta E, Veicsteinas A, Esposito F. Electromechanical delay components during relaxation after voluntary contraction: reliability and effects of fatigue. Muscle Nerve 2015; 51:907-15. [PMID: 25256098 DOI: 10.1002/mus.24466] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/22/2014] [Indexed: 11/10/2022]
Abstract
INTRODUCTION Fatigue effects on total relaxation delay (R-DelayTOT ) components and measurement reliability were investigated. METHODS Electromyogram (EMG), force (F), and mechanomyogram (MMG) were recorded during maximum voluntary contraction from the biceps brachii muscle before and after fatigue. The delays between EMG cessation and onset of F decay (R-EMD), between F decay and onset of MMG largest displacement (MMG p-p) (R-Δt F-MMG), from the beginning to the end of MMG p-p (R-Δt MMGp-p ), and from the end of MMG p-p to F cessation (R-Δt MMG-Fend ) were calculated. RESULTS R-DelayTOT lasted 366 ± 10 ms. R-EMD, R-Δt F-MMG, R-Δt MMGp-p , and R-Δt MMG-Fend accounted for 6%, 8%, 59%, and 27% of R-DelayTOT , respectively. After fatigue, R-DelayTOT , R-EMD, R-Δt F-MMG, and R-Δt MMGp-p increased by 38%, 22%, 40%, 40%, and 38%, respectively (P<0.05). Reliability was very high (0.853-0.960). CONCLUSIONS R-Δt MMGp-p was the main contributor to R-DelayTOT . Fatigue affected all R-DelayTOT contributors, with a smaller effect on R-EMD.
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Affiliation(s)
- Emiliano Cè
- Department of Biomedical Sciences for Health, University of Milan, Via G. Colombo 71, 20133, Milan, Italy
| | - Susanna Rampichini
- Department of Biomedical Sciences for Health, University of Milan, Via G. Colombo 71, 20133, Milan, Italy
| | - Massimo Venturelli
- Department of Biomedical Sciences for Health, University of Milan, Via G. Colombo 71, 20133, Milan, Italy
| | - Eloisa Limonta
- Department of Biomedical Sciences for Health, University of Milan, Via G. Colombo 71, 20133, Milan, Italy
| | - Arsenio Veicsteinas
- Department of Biomedical Sciences for Health, University of Milan, Via G. Colombo 71, 20133, Milan, Italy.,Center of Sport Medicine, Don Gnocchi Foundation, Milan, Italy
| | - Fabio Esposito
- Department of Biomedical Sciences for Health, University of Milan, Via G. Colombo 71, 20133, Milan, Italy
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Hannah R, Stannard RL, Minshull C, Artioli GG, Harris RC, Sale C. β-Alanine supplementation enhances human skeletal muscle relaxation speed but not force production capacity. J Appl Physiol (1985) 2015; 118:604-12. [DOI: 10.1152/japplphysiol.00991.2014] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
β-Alanine (BA) supplementation improves human exercise performance. One possible explanation for this is an enhancement of muscle contractile properties, occurring via elevated intramuscular carnosine resulting in improved calcium sensitivity and handling. This study investigated the effect of BA supplementation on in vivo contractile properties and voluntary neuromuscular performance. Twenty-three men completed two experimental sessions, pre- and post-28 days supplementation with 6.4 g/day of BA ( n = 12) or placebo (PLA; n = 11). During each session, force was recorded during a series of knee extensor contractions: resting and potentiated twitches and octet (8 pulses, 300 Hz) contractions elicited via femoral nerve stimulation; tetanic contractions (1 s, 1–100 Hz) via superficial muscle stimulation; and maximum and explosive voluntary contractions. BA supplementation had no effect on the force-frequency relationship, or the force responses (force at 25 and 50 ms from onset, peak force) of resting or potentiated twitches, and octet contractions ( P > 0.05). Resting and potentiated twitch electromechanical delay and time-to-peak tension were unaffected by BA supplementation ( P > 0.05), although half-relaxation time declined by 7–12% ( P < 0.05). Maximum and explosive voluntary forces were unchanged after BA supplementation. BA supplementation had no effect on evoked force responses, implying that altered calcium sensitivity and/or release are not the mechanisms by which BA supplementation influences exercise performance. The reduced half-relaxation time with BA supplementation might, however, be explained by enhanced reuptake of calcium, which has implications for the efficiency of muscle contraction following BA supplementation.
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Affiliation(s)
- Ricci Hannah
- Sport, Health and Performance Enhancement (SHAPE) Research Group, School of Science and Technology, Nottingham Trent University, United Kingdom
| | - Rebecca Louise Stannard
- Sport, Health and Performance Enhancement (SHAPE) Research Group, School of Science and Technology, Nottingham Trent University, United Kingdom
| | - Claire Minshull
- Sport, Health and Performance Enhancement (SHAPE) Research Group, School of Science and Technology, Nottingham Trent University, United Kingdom
| | - Guilherme Giannini Artioli
- Laboratory of Applied Nutrition and Metabolism, School of Physical Education, University of São Paulo, São Paulo, Brazil; and
| | | | - Craig Sale
- Sport, Health and Performance Enhancement (SHAPE) Research Group, School of Science and Technology, Nottingham Trent University, United Kingdom
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In vivo calcium regulation in diabetic skeletal muscle. Cell Calcium 2014; 56:381-9. [PMID: 25224503 DOI: 10.1016/j.ceca.2014.08.008] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2014] [Revised: 07/23/2014] [Accepted: 08/09/2014] [Indexed: 01/30/2023]
Abstract
In skeletal muscle, dysfunctional contractile activity has been linked to impaired intracellular Ca(2+) concentration ([Ca(2+)]i) regulation. Muscle force production is impaired and fatigability and muscle fragility deteriorate with diabetes. Use of a novel in vivo model permits investigation of [Ca(2+)]i homeostasis in diabetic skeletal muscle. Within this in vivo environment we have shown that diabetes perturbs the Ca(2+) regulatory system such that resting [Ca(2+)]i homeostasis following muscle contractions is compromised and elevations of [Ca(2+)]i are exacerbated. This review considers the impact of diabetes on the capacity of skeletal muscle to regulate [Ca(2+)]i, following muscle contractions and, in particular, the relationship between muscle fatigue and elevated [Ca(2+)]i in a highly ecologically relevant circulation-intact environment. Importantly, the role of mitochondria in calcium sequestration and the possibility that diabetes impacts this process is explored. Given the profound microcirculatory dysfunction in diabetes this preparation offers the unique opportunity to study the interrelationships among microvascular function, blood-myocyte oxygen flux and [Ca(2+)]i as they relate to enhanced muscle fatigability and exercise intolerance.
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