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Robergs R, O’Malley B, Torrens S, Siegler J. The missing hydrogen ion, part-2: Where the evidence leads to. SPORTS MEDICINE AND HEALTH SCIENCE 2024; 6:94-100. [PMID: 38463661 PMCID: PMC10918345 DOI: 10.1016/j.smhs.2024.01.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2023] [Revised: 12/19/2023] [Accepted: 01/09/2024] [Indexed: 03/12/2024] Open
Abstract
The purpose of this manuscript was to present the evidence for why cells do not produce metabolic acids. In addition, evidence that opposes common viewpoints and arguments used to support the cellular production of lactic acid (HLa) or liver keto-acids have been provided. Organic chemistry reveals that many molecules involved in cellular energy catabolism contain functional groups classified as acids. The two main acidic functional groups of these molecules susceptible to ∼H+ release are the carboxyl and phosphoryl structures, though the biochemistry and organic chemistry of molecules having these structures reveal they are produced in a non-acidic ionic (negatively charged) structure, thereby preventing pH dependent ∼H+ release. Added evidence from the industrial production of HLa further reveals that lactate (La-) is produced followed by an acidification step that converts La- to HLa due to pH dependent ∼H+ association. Interestingly, there is a plentiful list of other molecules that are classified as acids and compared to HLa have similar values for their H+ dissociation constant (pKd). For many metabolic conditions, the cumulative turnover of these molecules is far higher than for La-. The collective evidence documents the non-empirical basis for the construct of the cellular production of HLa, or any other metabolic acid.
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Affiliation(s)
- Robert Robergs
- School of Exercise and Nutrition Sciences, Queensland University of Technology, Kelvin Grove, Queensland, 4059, Australia
| | - Bridgette O’Malley
- School of Exercise and Nutrition Sciences, Queensland University of Technology, Kelvin Grove, Queensland, 4059, Australia
| | - Sam Torrens
- School of Exercise and Nutrition Sciences, Queensland University of Technology, Kelvin Grove, Queensland, 4059, Australia
| | - Jason Siegler
- ASU Health Futures Center, College of Health Solutions, Arizona State University, 6161 East Mayo Blvd, Phoenix, 85054, Arizona, USA
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Fehr CM, McEwen G, Robinson C. The Effects of "Physical BEMER® Vascular Therapy" on Work Performed During Repeated Wingate Sprints. RESEARCH QUARTERLY FOR EXERCISE AND SPORT 2023; 94:732-737. [PMID: 35481952 DOI: 10.1080/02701367.2022.2053040] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/23/2021] [Accepted: 03/05/2022] [Indexed: 06/14/2023]
Abstract
Purpose: The purpose of this study was to investigate the effects of Bio-Electro-Magnetic-Energy-Regulation (BEMER) on recovery and performance parameters in anaerobic exercise compared to active and passive recovery. Method: Fifteen recreationally active participants completed four sessions separated by 2-5 days between each session. The first visit involved one Wingate Anaerobic Test (WAnT; 30-s cycling sprint on a Monark ergometer) to familiarize participants with testing procedures. The three subsequent sessions involved four repeated WAnTs. Each sprint was followed by 4 min of either passive recovery (laying supine), active recovery (pedaling at 50 rpm at 20% of sprint workload), or BEMER recovery (laying supine on the BEMER body pad at intensity level "5-Plus."). The same recovery method was used within each testing session, and recovery method order was randomized across participants. Results: There was no difference in peak power, average power, fatigue index, or average work performed between recovery conditions. Active recovery resulted in a statistically significant decrease in ratings of pain intensity (M = -0.767, SD = 0.928) and pain unpleasantness (M = -0.608, SD = 0.915), from the first minute to the fourth minute of recovery, compared to both BEMER (Intensity: M = 0.675, SD = 0.745, Unpleasantness: M = 1.125, SD = 0.862) and passive (Intensity: M = 0.542, SD = 0.774, Unpleasantness: M = 1.018, SD = 0.872) recoveries, where pain ratings increased. Conclusions: Although no recovery method resulted in increased performance, active recovery led to a more comfortable exercise experience while still allowing comparable exercise performance.
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Robergs RA. Quantifying H + exchange from muscle cytosolic energy catabolism using metabolite flux and H + coefficients from multiple competitive cation binding: New evidence for consideration in established theories. Physiol Rep 2021; 9:e14728. [PMID: 33904663 PMCID: PMC8077081 DOI: 10.14814/phy2.14728] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2019] [Revised: 10/18/2020] [Accepted: 01/03/2021] [Indexed: 11/30/2022] Open
Abstract
The purpose of this investigation was to present calculations of fractional H+ exchange (~H+e ) from the chemical reactions of non-mitochondrial energy catabolism. Data of muscle pH and metabolite accumulation were based on published research for intense exercise to contractile failure within ~3 min, from which capacities and time profiles were modeled. Data were obtained from prior research for multiple competitive cation dissociation constants of metabolites and the chemical reactions of non-mitochondrial energy catabolism, and pH dependent calculations of ~H+e from specific chemical reactions. Data revealed that the 3 min of intense exercise incurred a total ATP turnover of 142.5 mmol L-1 , with a total intramuscular ~H+ exchange (-'ve = release) of -187.9 mmol L-1 . Total ~H+ metabolic consumption was 130.6 mmol L-1 , revealing a net total ~H+e (~H+te ) of -57.3 mmol L-1 . Lactate production had a ~H+te of 44.2 mmol L-1 (for a peak accumulation = 45 mmol L-1 ). The net ~H+te for the sum of the CK, AK, and AMPD reactions was 36.33 mmol L-1 . The ~H+te from ATP turnover equaled -47.5 mmol L-1 . The total ~H+ release to lactate ratio was 4.3 (187.9/44). Muscle ~H+ release during intense exercise is up to ~4-fold larger than previously assumed based on the lactic acid construct.
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Affiliation(s)
- Robert A. Robergs
- School of Exercise and Nutrition SciencesFaculty of HealthQueensland University of TechnologyKelvin GroveQLDAustralia
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Rosenstein PG, Tennent-Brown BS, Hughes D. Clinical use of plasma lactate concentration. Part 1: Physiology, pathophysiology, and measurement. J Vet Emerg Crit Care (San Antonio) 2018. [PMID: 29533512 DOI: 10.1111/vec.12708] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
OBJECTIVE To review the current literature with respect to the physiology, pathophysiology, and measurement of lactate. DATA SOURCES Data were sourced from veterinary and human clinical trials, retrospective studies, experimental studies, and review articles. Articles were retrieved without date restrictions and were sourced primarily via PubMed, Scopus, and CAB Abstracts as well as by manual selection. HUMAN AND VETERINARY DATA SYNTHESIS Lactate is an important energy storage molecule, the production of which preserves cellular energy production and mitigates the acidosis from ATP hydrolysis. Although the most common cause of hyperlactatemia is inadequate tissue oxygen delivery, hyperlactatemia can, and does occur in the face of apparently adequate oxygen supply. At a cellular level, the pathogenesis of hyperlactatemia varies widely depending on the underlying cause. Microcirculatory dysfunction, mitochondrial dysfunction, and epinephrine-mediated stimulation of Na+ -K+ -ATPase pumps are likely important contributors to hyperlactatemia in critically ill patients. Ultimately, hyperlactatemia is a marker of altered cellular bioenergetics. CONCLUSION The etiology of hyperlactatemia is complex and multifactorial. Understanding the relevant pathophysiology is helpful when characterizing hyperlactatemia in clinical patients.
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Affiliation(s)
- Patricia G Rosenstein
- Department of Veterinary Clinical Sciences, Faculty of Veterinary and Agricultural Sciences, University of Melbourne, Werribee, Victoria, Australia
| | - Brett S Tennent-Brown
- Department of Veterinary Clinical Sciences, Faculty of Veterinary and Agricultural Sciences, University of Melbourne, Werribee, Victoria, Australia
| | - Dez Hughes
- Department of Veterinary Clinical Sciences, Faculty of Veterinary and Agricultural Sciences, University of Melbourne, Werribee, Victoria, Australia
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5
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Qian Q. Reply to Robergs et al. Physiology (Bethesda) 2018; 33:13. [PMID: 29212887 DOI: 10.1152/physiol.00034.2017] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2017] [Accepted: 10/30/2017] [Indexed: 11/22/2022] Open
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Robergs RA. Competitive cation binding computations of proton balance for reactions of the phosphagen and glycolytic energy systems within skeletal muscle. PLoS One 2017; 12:e0189822. [PMID: 29267370 PMCID: PMC5739460 DOI: 10.1371/journal.pone.0189822] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2017] [Accepted: 12/02/2017] [Indexed: 01/11/2023] Open
Abstract
Limited research and data has been published for the H+ coefficients for the metabolites and reactions involved in non-mitochondrial energy metabolism. The purpose of this investigation was to compute the fractional binding of H+, K+, Na+ and Mg2+ to 21 metabolites of skeletal muscle non-mitochondrial energy metabolism, resulting in 104 different metabolite-cation complexes. Fractional binding of H+ to these metabolite-cation complexes were applied to 17 reactions of skeletal muscle non-mitochondrial energy metabolism, and 8 conditions of the glycolytic pathway based on the source of substrate (glycogen vs. glucose), completeness of glycolytic flux, and the end-point of pyruvate vs. lactate. For pH conditions of 6.0 and 7.0, respectively, H+ coefficients (-‘ve values = H+ release) for the creatine kinase, adenylate kinase, AMP deaminase and ATPase reactions were 0.8 and 0.97, -0.13 and -0.02, 1.2 and 1.09, and -0.01 and -0.66, respectively. The glycolytic pathway is net H+ releasing, regardless of lactate production, which consumes 1 H+. For glycolysis fueled by glycogen and ending in either pyruvate or lactate, H+ coefficients for pH 6.0 and 7.0 were -3.97 and -2.01 (pyruvate), and -1.96 and -0.01 (lactate), respectively. When starting with glucose, the same conditions result in H+ coefficients of -3.98 and -2.67, and -1.97 and –0.67, respectively. The most H+ releasing reaction of glycolysis is the glyceraldehyde-3-phosphate dehydrogenase reaction, with H+ coefficients for pH 6.0 and 7.0 of -1.58 and -0.76, respectively. Incomplete flux of substrate through glycolysis would increase net H+ release due to the absence of the pyruvate kinase and lactate dehydrogenase reactions, which collectively result in H+ coefficients for pH 6.0 and 7.0 of 1.35 and 1.88, respectively. The data presented provide an extensive reference source for academics and researchers to accurately profile the balance of protons for all metabolites and reactions of non-mitochondrial energy metabolism, and reveal the greater role of glycolysis in net H+ release than previously assumed. The data can also be used to improve the understanding of the cause of metabolic acidosis, and reveal mechanistic connections between H+ release within and from muscle and the electrochemical neutrality concepts that further refine acid-base balance in biological solutions.
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Affiliation(s)
- Robert Andrew Robergs
- School of Exercise and Nutrition Sciences, Faculty of Health, Queensland University of Technology, Kelvin Grove, Queensland, Australia
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Divakaruni AS, Paradyse A, Ferrick DA, Murphy AN, Jastroch M. Analysis and interpretation of microplate-based oxygen consumption and pH data. Methods Enzymol 2015; 547:309-54. [PMID: 25416364 DOI: 10.1016/b978-0-12-801415-8.00016-3] [Citation(s) in RCA: 323] [Impact Index Per Article: 35.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Breakthrough technologies to measure cellular oxygen consumption and proton efflux are reigniting the study of cellular energetics by increasing the scope and pace with which discoveries are made. As we learn the variation in metabolism between cell types is large, it is helpful to continually provide additional perspectives and update our roadmap for data interpretation. In that spirit, this chapter provides the following for those conducting microplate-based oxygen consumption experiments: (i) a description of the standard parameters for measuring respiration in intact cells, (ii) a framework for data analysis and normalization, and (iii) examples of measuring respiration in permeabilized cells to follow up results observed with intact cells. Additionally, rate-based measurements of extracellular pH are increasingly used as a qualitative indicator of glycolytic flux. As a resource to help interpret these measurements, this chapter also provides a detailed accounting of proton production during glucose oxidation in the context of plate-based assays.
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Affiliation(s)
- Ajit S Divakaruni
- Department of Pharmacology, University of California, San Diego, California, USA.
| | - Alexander Paradyse
- Department of Pharmacology, University of California, San Diego, California, USA
| | | | - Anne N Murphy
- Department of Pharmacology, University of California, San Diego, California, USA
| | - Martin Jastroch
- Institute for Diabetes and Obesity, Helmholtz Zentrum München, German Research Center for Environmental Health, Neuherberg, Germany
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Olausson P, Gerdle B, Ghafouri N, Sjöström D, Blixt E, Ghafouri B. Protein alterations in women with chronic widespread pain--An explorative proteomic study of the trapezius muscle. Sci Rep 2015; 5:11894. [PMID: 26150212 PMCID: PMC4493691 DOI: 10.1038/srep11894] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2015] [Accepted: 06/09/2015] [Indexed: 12/18/2022] Open
Abstract
Chronic widespread pain (CWP) has a high prevalence in the population and is associated with prominent negative individual and societal consequences. There is no clear consensus concerning the etiology behind CWP although alterations in the central processing of nociception maintained by peripheral nociceptive input has been suggested. Here, we use proteomics to study protein changes in trapezius muscle from 18 female patients diagnosed with CWP compared to 19 healthy female subjects. The 2-dimensional gel electrophoresis (2-DE) in combination with multivariate statistical analyses revealed 17 proteins to be differently expressed between the two groups. Proteins were identified by mass spectrometry. Many of the proteins are important enzymes in metabolic pathways like the glycolysis and gluconeogenesis. Other proteins are associated with muscle damage, muscle recovery, stress and inflammation. The altered expressed levels of these proteins suggest abnormalities and metabolic changes in the myalgic trapezius muscle in CWP. Taken together, this study gives further support that peripheral factors may be of importance in maintaining CWP.
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Affiliation(s)
- Patrik Olausson
- Division of Community Medicine, Department of Medical and Health Sciences, Faculty of Health Sciences, Linköping University and Pain and Rehabilitation Center, Anaesthetics, Operations and Specialty Surgery Center, Region Östergötland
| | - Björn Gerdle
- Division of Community Medicine, Department of Medical and Health Sciences, Faculty of Health Sciences, Linköping University and Pain and Rehabilitation Center, Anaesthetics, Operations and Specialty Surgery Center, Region Östergötland
| | - Nazdar Ghafouri
- Division of Community Medicine, Department of Medical and Health Sciences, Faculty of Health Sciences, Linköping University and Pain and Rehabilitation Center, Anaesthetics, Operations and Specialty Surgery Center, Region Östergötland
| | - Dick Sjöström
- Division of Community Medicine, Department of Medical and Health Sciences, Faculty of Health Sciences, Linköping University and Pain and Rehabilitation Center, Anaesthetics, Operations and Specialty Surgery Center, Region Östergötland
| | - Emelie Blixt
- Division of Community Medicine, Department of Medical and Health Sciences, Faculty of Health Sciences, Linköping University and Pain and Rehabilitation Center, Anaesthetics, Operations and Specialty Surgery Center, Region Östergötland
| | - Bijar Ghafouri
- Division of Community Medicine, Department of Medical and Health Sciences, Faculty of Health Sciences, Linköping University and Pain and Rehabilitation Center, Anaesthetics, Operations and Specialty Surgery Center, Region Östergötland
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Caruso J, Charles J, Unruh K, Giebel R, Learmonth L, Potter W. Ergogenic effects of β-alanine and carnosine: proposed future research to quantify their efficacy. Nutrients 2012; 4:585-601. [PMID: 22852051 PMCID: PMC3407982 DOI: 10.3390/nu4070585] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2012] [Revised: 06/11/2012] [Accepted: 06/18/2012] [Indexed: 11/30/2022] Open
Abstract
β-alanine is an amino acid that, when combined with histidine, forms the dipeptide carnosine within skeletal muscle. Carnosine and β-alanine each have multiple purposes within the human body; this review focuses on their roles as ergogenic aids to exercise performance and suggests how to best quantify the former’s merits as a buffer. Carnosine normally makes a small contribution to a cell’s total buffer capacity; yet β-alanine supplementation raises intracellular carnosine concentrations that in turn improve a muscle’s ability to buffer protons. Numerous studies assessed the impact of oral β-alanine intake on muscle carnosine levels and exercise performance. β-alanine may best act as an ergogenic aid when metabolic acidosis is the primary factor for compromised exercise performance. Blood lactate kinetics, whereby the concentration of the metabolite is measured as it enters and leaves the vasculature over time, affords the best opportunity to assess the merits of β-alanine supplementation’s ergogenic effect. Optimal β-alanine dosages have not been determined for persons of different ages, genders and nutritional/health conditions. Doses as high as 6.4 g day−1, for ten weeks have been administered to healthy subjects. Paraesthesia is to date the only side effect from oral β-alanine ingestion. The severity and duration of paraesthesia episodes are dose-dependent. It may be unwise for persons with a history of paraesthesia to ingest β-alanine. As for any supplement, caution should be exercised with β-alanine supplementation.
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Affiliation(s)
- John Caruso
- Exercise & Sports Science Program, The University of Tulsa, Tulsa, OK 74104, USA; (J.C.); (K.U.); (R.G.); (L.L.)
- Author to whom correspondence should be addressed; ; Tel.: +1-918-631-2924; Fax: +1-918-631-2068
| | - Jessica Charles
- Exercise & Sports Science Program, The University of Tulsa, Tulsa, OK 74104, USA; (J.C.); (K.U.); (R.G.); (L.L.)
| | - Kayla Unruh
- Exercise & Sports Science Program, The University of Tulsa, Tulsa, OK 74104, USA; (J.C.); (K.U.); (R.G.); (L.L.)
| | - Rachel Giebel
- Exercise & Sports Science Program, The University of Tulsa, Tulsa, OK 74104, USA; (J.C.); (K.U.); (R.G.); (L.L.)
| | - Lexis Learmonth
- Exercise & Sports Science Program, The University of Tulsa, Tulsa, OK 74104, USA; (J.C.); (K.U.); (R.G.); (L.L.)
| | - William Potter
- Department of Chemistry & Biochemistry, The University of Tulsa, Tulsa, OK 74104, USA;
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Lactate and the GPR81 receptor in metabolic regulation: implications for adipose tissue function and fatty acid utilisation by muscle during exercise. Br J Nutr 2011; 106:1310-6. [PMID: 21902860 DOI: 10.1017/s0007114511004673] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Lactate is increasingly recognised to be more than a simple end product of anaerobic glycolysis. Skeletal muscle and white adipose tissue are considered to be the main sites of lactate production and release. Recent studies have demonstrated that there is a specific G-protein coupled receptor for lactate, GPR81, which is expressed primarily in adipose tissue, and also in muscle. Lactate inhibits lipolysis in adipose tissue by mediating, through GPR81, the anti-lipolytic action of insulin. A high proportion (50 % or more) of the glucose utilised by white adipose tissue is converted to lactate and lactate production by the tissue increases markedly in obesity; this is likely to reflect a switch towards anaerobic metabolism with the development of hypoxia in the tissue. During exercise, there is a shift in fuel utilisation by muscle from lipid to carbohydrate, but this does not appear to be a result of the inhibition of lipolysis in the main adipose tissue depots by muscle-derived lactate. It is suggested instead that a putative autocrine lactate loop in myocytes may regulate fuel utilisation by muscle during exercise, operating via a muscle GPR81 receptor. In addition to being an important substrate, lactate is a key signal in metabolic regulation.
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Vinnakota KC, Kushmerick MJ. Point: Muscle lactate and H+ production do have a 1:1 association in skeletal muscle. J Appl Physiol (1985) 2011; 110:1487-9; discussion 1497. [DOI: 10.1152/japplphysiol.01506.2010] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Affiliation(s)
- Kalyan C. Vinnakota
- Biotechnology and Bioengineering Center
- Department of Physiology Medical College of Wisconsin Milwaukee, Wisconsin
| | - Martin J. Kushmerick
- Departments of Radiology and
- Bioengineering and
- Physiology and Biophysics University of Washington Seattle, Washington
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Beard DA. Comments on Point:Counterpoint: Muscle lactate and H⁺ production do/do not have a 1:1 association in skeletal muscle. Calculations of Robergs support the view of Vinnakota and Kushmerick. J Appl Physiol (1985) 2011; 110:1493. [PMID: 21372102 PMCID: PMC5395467 DOI: 10.1152/japplphysiol.00242.2011] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
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Vinnakota KC, Rusk J, Palmer L, Shankland E, Kushmerick MJ. Common phenotype of resting mouse extensor digitorum longus and soleus muscles: equal ATPase and glycolytic flux during transient anoxia. J Physiol 2010; 588:1961-83. [PMID: 20308252 DOI: 10.1113/jphysiol.2009.185934] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
Rates of ATPase and glycolysis are several times faster in actively contracting mouse extensor digitorum longus muscle (EDL) than soleus (SOL), but we find these rates are not distinguishable at rest. We used a transient anoxic perturbation of steady state energy balance to decrease phosphocreatine (PCr) reversibly and to measure the rates of ATPase and of lactate production without muscle activation or contraction. The rate of glycolytic ATP synthesis is less than the ATPase rate, accounting for the continual PCr decrease during anoxia in both muscles. We fitted a mathematical model validated with properties of enzymes and solutes measured in vitro and appropriate for the transient perturbation of these muscles to experimental data to test whether the model accounts for the results. Simulations showed equal rates of ATPase and lactate production in both muscles. ATPase controls glycolytic flux by feedback from its products. Adenylate kinase function is critical because a rise in [AMP] is necessary to activate glycogen phosphorylase. ATPase is the primary source of H+ production. The sum of contributions of the 13 reactions of the glycogenolytic and glycolytic network to total proton load is negligible. The stoichiometry of lactate and H+ production is near unity. These results identify a default state of energy metabolism for resting muscle in which there is no difference in the metabolic phenotype of EDL and SOL. Therefore, additional control mechanisms, involving higher ATPase flux and [Ca2+], must exist to explain the well-known difference in glycolytic rates in fast-twitch and slow-twitch muscles in actively contracting muscle.
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Affiliation(s)
- Kalyan C Vinnakota
- University of Washington, Mail Box 357115, Department of Radiology, 1959 NE Pacific Avenue, HSC AA010, Seattle, WA 09105-7115, USA
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Macedo DV, Lazarim FL, Catanho da Silva FO, Tessuti LS, Hohl R. Is lactate production related to muscular fatigue? A pedagogical proposition using empirical facts. ADVANCES IN PHYSIOLOGY EDUCATION 2009; 33:302-307. [PMID: 19948679 DOI: 10.1152/advan.00039.2009] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
The cause-effect relationship between lactic acid, acidosis, and muscle fatigue has been established in the literature. However, current experiments contradict this premise. Here, we describe an experiment developed by first-year university students planned to answer the following questions: 1) Which metabolic pathways of energy metabolism are responsible for meeting the high ATP demand during high-intensity intermittent exercise? 2) Which metabolic pathways are active during the pause, and how do they influence phosphocreatine synthesis? and 3) Is lactate production related to muscular fatigue? Along with these questions, students received a list of materials available for the experiment. In the classroom, they proposed two protocols of eight 30-m sprints at maximum speed, one protocol with pauses of 120 s and the other protocol with pauses of 20 s between sprints. Their performances were analyzed through the velocity registered by photocells. Blood lactate was analyzed before the first sprint and after the eighth sprint. Blood uric acid was analyzed before exercise and 15 and 60 min after exercises. When discussing the data, students concluded that phosphocreatine restoration is time dependent, and this fact influenced the steady level of performance in the protocol with pauses of 120 s compared with the performance decrease noted in the protocol with pauses of 20 s. As the blood lactate levels showed similar absolute increases after both exercises, the students concluded that lactate production is not related to the performance decrement. This activity allows students to integrate the understanding of muscular energy pathways and to reconsider a controversial concept with facts that challenge the universality of the hypothesis relating lactate production to muscular fatigue.
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Affiliation(s)
- Denise Vaz Macedo
- Exercise Biochemistry Laboratory, Biochemistry Department, Biology Institute, State University of Campinas, Campinas, São Paulo, Brazil.
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Böning D, Maassen N. Point:Counterpoint: Lactic acid is/is not the only physicochemical contributor to the acidosis of exercise. J Appl Physiol (1985) 2008; 105:358-9. [DOI: 10.1152/japplphysiol.00162.2008] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
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Abstract
The cell-to-cell lactate shuttle was introduced in 1984 and has been repeatedly supported by studies using a variety of experimental approaches. Because of its large mass and metabolic capacity, skeletal muscle is probably the major component of the lactate shuttle in terms of both production and consumption. Muscles exercising in a steady state are avid consumers of lactate, using most of the lactate as an oxidative fuel. Cardiac muscle is highly oxidative and readily uses lactate as a fuel. Lactate is a major gluconeogenic substrate for the liver; the use of lactate to form glucose increases when blood lactate concentration is elevated. Illustrative of the widespread shuttling of lactate, even the brain takes up lactate when the blood level is increased. Recently, an intracellular lactate shuttle has also been proposed. Although disagreements abound, current evidence suggests that lactate is the primary end-product of glycolysis at cellular sites remote from mitochondria. This lactate could subsequently diffuse to areas adjacent to mitochondria. Evidence is against lactate oxidation within the mitochondrial matrix, but a viable hypothesis is that lactate could be converted to pyruvate by a lactate oxidation complex with lactate dehydrogenase located on the outer surface of the inner mitochondrial membrane. In another controversial area, the role of lactic acid in acid-base balance has been hotly debated in recent times. Careful analysis reveals that lactate, not lactic acid, is the substrate/product of metabolic reactions. One view is that lactate formation alleviates acidosis, whereas another is that lactate is a causative factor in acidosis. Surprisingly, there is little direct mechanistic evidence regarding cause and effect in acid-base balance. However, there is insufficient evidence to discard the term "lactic acidosis."
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Affiliation(s)
- L Bruce Gladden
- Department of Kinesiology, Auburn University, Auburn, AL 36849-5323, USA.
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Kemp G. Muscle cell volume and pH changes due to glycolytic ATP synthesis. J Physiol 2007; 582:461-5; author reply 467-70. [PMID: 17446216 PMCID: PMC2075294 DOI: 10.1113/jphysiol.2007.134643] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
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Böning D, Klarholz C, Himmelsbach B, Hütler M, Maassen N. Causes of differences in exercise-induced changes of base excess and blood lactate. Eur J Appl Physiol 2006; 99:163-71. [PMID: 17115177 DOI: 10.1007/s00421-006-0328-0] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/05/2006] [Indexed: 11/25/2022]
Abstract
It has been concluded from comparisons of base excess (BE) and lactic acid (La) concentration changes in blood during exercise-induced acidosis that more H+ than La- leave the muscle and enter interstitial fluid and blood. To examine this, we performed incremental cycle tests in 13 untrained males and measured acid-base status and [La] in arterialized blood, plasma, and red cells until 21 min after exhaustion. The decrease of actual BE (-deltaABE) was 2.2 +/- 0.5 (SEM) mmol l(-1) larger than the increase of [La]blood at exhaustion, and the difference rose to 4.8 +/- 0.5 mmol l(-1) during the first minutes of recovery. The decrease of standard BE (SBE), a measure of mean BE of interstitial fluid (if) and blood, however, was smaller than the increase of [La] in the corresponding volume (delta[La](if+blood)) during exercise and only slightly larger during recovery. The discrepancy between -deltaABE and delta[La]blood mainly results from the Donnan effect hindering the rise of [La]erythrocyte to equal values like [La]plasma. The changing Donnan effect during acidosis causes that Cl- from the interstitial fluid enter plasma and erythrocytes in exchange for HCO3(-). A corresponding amount of La- remains outside the blood. SBE is not influenced by ion shifts among these compartments and therefore is a rather exact measure of acid movements across tissue cell membranes, but changes have been compared previously to delta[La]blood instead to delta[La](if+blood). When performing correct comparisons and considering Cl-/HCO3(-) exchange between erythrocytes and extracellular fluid, neither the use of deltaABE nor of deltaSBE provides evidence for differences in H+ and La- transport across the tissue cell membranes.
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Affiliation(s)
- Dieter Böning
- Institute of Sports Medicine, Charité, University Medicine Berlin, Arnimallee 22, 14195, Berlin, Germany.
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Philp A, Macdonald AL, Watt PW. Lactate--a signal coordinating cell and systemic function. ACTA ACUST UNITED AC 2006; 208:4561-75. [PMID: 16326938 DOI: 10.1242/jeb.01961] [Citation(s) in RCA: 211] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Since its first documented observation in exhausted animal muscle in the early 19th century, the role of lactate (lactic acid) has fascinated muscle physiologists and biochemists. Initial interpretation was that lactate appeared as a waste product and was responsible in some way for exhaustion during exercise. Recent evidence, and new lines of investigation, now place lactate as an active metabolite, capable of moving between cells, tissues and organs, where it may be oxidised as a fuel or reconverted to form pyruvate or glucose. The questions now to be asked concern the effects of lactate at the systemic and cellular level on metabolic processes. Does lactate act as a metabolic signal to specific tissues, becoming a metabolite pseudo-hormone? Does lactate have a role in whole-body coordination of sympathetic/parasympathetic nerve system control? And, finally, does lactate play a role in maintaining muscle excitability during intense muscle contraction? The concept of lactate acting as a signalling compound is a relatively new hypothesis stemming from a combination of comparative, cell and whole-organism investigations. It has been clearly demonstrated that lactate is capable of entering cells via the monocarboxylate transporter (MCT) protein shuttle system and that conversion of lactate to and from pyruvate is governed by specific lactate dehydrogenase isoforms, thereby forming a highly adaptable metabolic intermediate system. This review is structured in three sections, the first covering pertinent topics in lactate's history that led to the model of lactate as a waste product. The second section will discuss the potential of lactate as a signalling compound, and the third section will identify ways in which such a hypothesis might be investigated. In examining the history of lactate research, it appears that periods have occurred when advances in scientific techniques allowed investigation of this metabolite to expand. Similar to developments made first in the 1920s and then in the 1980s, contemporary advances in stable isotope, gene microarray and RNA interference technologies may allow the next stage of understanding of the role of this compound, so that, finally, the fundamental questions of lactate's role in whole-body and localised muscle function may be answered.
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Affiliation(s)
- Andrew Philp
- Department of Sport and Exercise Sciences, Chelsea School Research Centre, Welkin Performance Laboratories, Eastbourne, BN20 7SP, UK.
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Kemp G, Böning D, Beneke R, Maassen N. Explaining pH Change in Exercising Muscle: Lactic acid, Proton Consumption, and Buffering vs. Strong Ion Difference. Am J Physiol Regul Integr Comp Physiol 2006; 291:R235-7; author reply R238-9. [PMID: 16760335 DOI: 10.1152/ajpregu.00662.2005] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The development of acidosis during intense exercise has traditionally been explained by the increased production of lactic acid, causing the release of a proton and the formation of the acid salt sodium lactate. On the basis of this explanation, if the rate of lactate production is high enough, the cellular proton buffering capacity can be exceeded, resulting in a decrease in cellular pH. These biochemical events have been termed lactic acidosis. The lactic acidosis of exercise has been a classic explanation of the biochemistry of acidosis for more than 80 years. This belief has led to the interpretation that lactate production causes acidosis and, in turn, that increased lactate production is one of the several causes of muscle fatigue during intense exercise. This review presents clear evidence that there is no biochemical support for lactate production causing acidosis. Lactate production retards, not causes, acidosis. Similarly, there is a wealth of research evidence to show that acidosis is caused by reactions other than lactate production. Every time ATP is broken down to ADP and Pi, a proton is released. When the ATP demand of muscle contraction is met by mitochondrial respiration, there is no proton accumulation in the cell, as protons are used by the mitochondria for oxidative phosphorylation and to maintain the proton gradient in the intermembranous space. It is only when the exercise intensity increases beyond steady state that there is a need for greater reliance on ATP regeneration from glycolysis and the phosphagen system. The ATP that is supplied from these nonmitochondrial sources and is eventually used to fuel muscle contraction increases proton release and causes the acidosis of intense exercise. Lactate production increases under these cellular conditions to prevent pyruvate accumulation and supply the NAD+ needed for phase 2 of glycolysis. Thus increased lactate production coincides with cellular acidosis and remains a good indirect marker for cell metabolic conditions that induce metabolic acidosis. If muscle did not produce lactate, acidosis and muscle fatigue would occur more quickly and exercise performance would be severely impaired.
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Ford LE, Gilbert SH. The importance of maturational studies in airway smooth muscle. Am J Physiol Lung Cell Mol Physiol 2005; 289:L898-901. [PMID: 16280458 DOI: 10.1152/ajplung.00328.2005] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
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Lindinger MI, Kowalchuk JM, Heigenhauser GJF. Applying physicochemical principles to skeletal muscle acid-base status. Am J Physiol Regul Integr Comp Physiol 2005; 289:R891-4; author reply R904-910. [PMID: 16105823 DOI: 10.1152/ajpregu.00225.2005] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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Robergs RA, Ghiasvand F, Parker D. Lingering construct of lactic acidosis. Am J Physiol Regul Integr Comp Physiol 2005. [DOI: 10.1152/ajpregu.00117.2005] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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