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Cairns SP, Renaud JM. The potassium-glycogen interaction on force and excitability in mouse skeletal muscle: implications for fatigue. J Physiol 2023; 601:5669-5687. [PMID: 37934587 DOI: 10.1113/jp285129] [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: 06/10/2023] [Accepted: 10/17/2023] [Indexed: 11/08/2023] Open
Abstract
A reduced muscle glycogen content and potassium (K+ ) disturbances across muscle membranes occur concomitantly during repeated intense exercise and together may contribute to skeletal muscle fatigue. Therefore, we examined whether raised extracellular K+ concentration ([K+ ]o ) (4 to 11 mM) interacts with lowered glycogen to reduce force production. Isometric contractions were evoked in isolated mouse soleus muscles (37°C) using direct supramaximal field stimulation. (1) Glycogen declined markedly in non-fatigued muscle with >2 h exposure in glucose-free physiological saline compared with control solutions (11 mM glucose), i.e. to <45% control. (2) Severe glycogen depletion was associated with increased 5'-AMP-activated protein kinase activity, indicative of metabolic stress. (3) The decline of peak tetanic force at 11 mM [K+ ]o was exacerbated from 67% initial at normal glycogen to 22% initial at lowered glycogen. This was due to a higher percentage of inexcitable fibres (71% vs. 43%), yet without greater sarcolemmal depolarisation or smaller amplitude action potentials. (4) Returning glucose while at 11 mM [K+ ]o increased both glycogen and force. (5) Exposure to 4 mM [K+ ]o glucose-free solutions (15 min) did not increase fatiguability during repeated tetani; however, after recovery there was a greater force decline at 11 mM [K+ ]o at lower than normal glycogen. (6) An important exponential relationship was established between relative peak tetanic force at 11 mM [K+ ]o and muscle glycogen content. These findings provide direct evidence of a synergistic interaction between raised [K+ ]o and lowered muscle glycogen as the latter shifts the peak tetanic force-resting EM relationship towards more negative resting EM due to lowered sarcolemmal excitability, which hence may contribute to muscle fatigue. KEY POINTS: Diminished muscle glycogen levels and raised extracellular potassium concentrations ([K+ ]o ) occur simultaneously during intense exercise and together may contribute to muscle fatigue. Prolonged exposure of isolated non-fatigued soleus muscles of mice to glucose-free physiological saline solutions markedly lowered muscle glycogen levels, as does fatigue then recovery in glucose-free solutions. For both approaches, the subsequent decline of maximal force at 11 mM [K+ ]o , which mimics interstitial [K+ ] levels during intense exercise, was exacerbated at lowered compared with normal glycogen. This was mainly due to many more muscle fibres becoming inexcitable. We established an important relationship that provides evidence of a synergistic interaction between raised [K+ ]o and lowered glycogen content to reduce force production. This paper indicates that partially lowered muscle glycogen (and/or metabolic stress) together with elevated interstitial [K+ ] interactively lowers muscle force, and hence may diminish performance especially during repeated high-intensity exercise.
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Affiliation(s)
- Simeon P Cairns
- SPRINZ, School of Sport and Recreation, Faculty of Health and Environmental Sciences, Auckland University of Technology, New Zealand
- Health and Rehabilitation Research Institute, Faculty of Health and Environmental Sciences, Auckland University of Technology, New Zealand
| | - Jean-Marc Renaud
- Department of Cellular and Molecular Medicine, Neuromuscular Research Center, University of Ottawa, Ottawa, Ontario, Canada
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2
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Renaud JM, Ørtenblad N, McKenna MJ, Overgaard K. Exercise and fatigue: integrating the role of K +, Na + and Cl - in the regulation of sarcolemmal excitability of skeletal muscle. Eur J Appl Physiol 2023; 123:2345-2378. [PMID: 37584745 PMCID: PMC10615939 DOI: 10.1007/s00421-023-05270-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2023] [Accepted: 06/29/2023] [Indexed: 08/17/2023]
Abstract
Perturbations in K+ have long been considered a key factor in skeletal muscle fatigue. However, the exercise-induced changes in K+ intra-to-extracellular gradient is by itself insufficiently large to be a major cause for the force decrease during fatigue unless combined to other ion gradient changes such as for Na+. Whilst several studies described K+-induced force depression at high extracellular [K+] ([K+]e), others reported that small increases in [K+]e induced potentiation during submaximal activation frequencies, a finding that has mostly been ignored. There is evidence for decreased Cl- ClC-1 channel activity at muscle activity onset, which may limit K+-induced force depression, and large increases in ClC-1 channel activity during metabolic stress that may enhance K+ induced force depression. The ATP-sensitive K+ channel (KATP channel) is also activated during metabolic stress to lower sarcolemmal excitability. Taking into account all these findings, we propose a revised concept in which K+ has two physiological roles: (1) K+-induced potentiation and (2) K+-induced force depression. During low-moderate intensity muscle contractions, the K+-induced force depression associated with increased [K+]e is prevented by concomitant decreased ClC-1 channel activity, allowing K+-induced potentiation of sub-maximal tetanic contractions to dominate, thereby optimizing muscle performance. When ATP demand exceeds supply, creating metabolic stress, both KATP and ClC-1 channels are activated. KATP channels contribute to force reductions by lowering sarcolemmal generation of action potentials, whilst ClC-1 channel enhances the force-depressing effects of K+, thereby triggering fatigue. The ultimate function of these changes is to preserve the remaining ATP to prevent damaging ATP depletion.
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Affiliation(s)
- Jean-Marc Renaud
- Faculty of Medicine, Department of Cellular and Molecular Medicine, University of Ottawa, 451 Smyth Rd., Ottawa, ON, K1H 8M5, Canada.
| | - Niels Ørtenblad
- Department of Sports Science and Clinical Biomechanics, University of Southern Denmark, Odense, Denmark
| | - Michael J McKenna
- Institute for Health and Sport, Victoria University, Melbourne, VIC, 8001, Australia
- College of Physical Education, Southwest University, Chongqing, China
- College of Sport Science, Zhuhai College of Science and Technology, Zhuhai, China
| | - Kristian Overgaard
- Exercise Biology, Department of Public Health, Aarhus University, Aarhus, Denmark
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3
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Gerwin RD. A New Unified Theory of Trigger Point Formation: Failure of Pre- and Post-Synaptic Feedback Control Mechanisms. Int J Mol Sci 2023; 24:ijms24098142. [PMID: 37175845 PMCID: PMC10179372 DOI: 10.3390/ijms24098142] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2023] [Accepted: 04/27/2023] [Indexed: 05/15/2023] Open
Abstract
The origin of the myofascial trigger point (TrP), an anomalous locus in muscle, has never been well-described. A new trigger point hypothesis (the new hypothesis) presented here addresses this lack. The new hypothesis is based on the concept that existing myoprotective feedback mechanisms that respond to muscle overactivity, low levels of adenosine triphosphate, (ATP) or a low pH, fail to protect muscle in certain circumstances, such as intense muscle activity, resulting in an abnormal accumulation of intracellular Ca2+, persistent actin-myosin cross bridging, and then activation of the nociceptive system, resulting in the formation of a trigger point. The relevant protective feedback mechanisms include pre- and postsynaptic sympathetic nervous system modulation, modulators of acetylcholine release at the neuromuscular junction, and mutations/variants or post-translational functional alterations in either of two ion channelopathies, the ryanodine receptor and the potassium-ATP ion channel, both of which exist in multiple mutation states that up- or downregulate ion channel function. The concepts that are central to the origin of at least some TrPs are the failure of protective feedback mechanisms and/or of certain ion channelopathies that are new concepts in relation to myofascial trigger points.
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Affiliation(s)
- Robert D Gerwin
- Department of Neurology, The Johns Hopkins School of Medicine, Baltimore, MD 21287, USA
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4
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Vargas-Vargas MA, Saavedra-Molina A, Gómez-Barroso M, Peña-Montes D, Cortés-Rojo C, Rodríguez-Orozco AR, Rocío MP. Diazoxide improves muscle function in association with improved dyslipidemia and decreased muscle oxidative stress in streptozotocin-induced diabetic rats. J Bioenerg Biomembr 2023; 55:71-78. [PMID: 36723797 DOI: 10.1007/s10863-023-09958-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2022] [Accepted: 01/22/2023] [Indexed: 02/02/2023]
Abstract
AIM/INTRODUCTION Diabetes Mellitus is a chronic degenerative disease, and its main biochemical characteristic is hyperglycemia due to impaired insulin secretion, resistance to peripheral actions of insulin, or both. Hyperglycemia causes dyslipidemia and stimulates oxidative damage, leading to the main symptoms, such as fatigue and culminates in diabetic complications. Previous studies have shown that ATP-sensitive potassium channels counteract muscle fatigue and metabolic stress in healthy mouse models. To determine the effect of diazoxide on muscle strength development during diabetes, we tested the effect of diazoxide in streptozotocin-diabetic rats in muscle function, lipid profile and oxidative stress biomarkers. MATERIALS AND METHODS Wistar rats were divided into 4 groups of six animals each: (1) Control group, (2) diabetes group, (3) Control group + diazoxide, and (4) Diabetic + diazoxide (DB + DZX). 4 weeks after rats were sacrificed, soleus and extensor digitorum longus muscles (EDL) were extracted to prepare homogenates and serum was obtained for biochemical measurements. Oxidative damage was evaluated by the thiobarbituric acid method and the fluorescent for reactive oxygen species (ROS) probe 2,4-H2DCFDA, respectively. RESULTS Diabetic rats with diazoxide administration showed an increase in the development of muscle strength in both muscles; in turn, the onset of fatigue was longer compared to the group of diabetic rats without treatment. Regarding the lipid profile, diazoxide decreased total cholesterol levels in the group of diabetic rats treated with diazoxide (x̅46.2 mg/dL) compared to the untreated diabetic group (x̅=104.4 mg/dL); secondly, diazoxide decreased triglyceride concentrations (x̅=105.3 mg/dL) compared to the untreated diabetic rats (x̅=412.2 mg/dL) as well as the levels of very low-density lipoproteins (x̅=20.4 mg/dL vs. x̅=82.44 mg/dL). Regarding the various markers of oxidative stress, the diabetic group treated with diazoxide was able to reduce the concentrations of TBARS and total reactive oxygen species as well as preserve the concentrations of reduced glutathione. CONCLUSION Diazoxide administration in diabetic rats increases muscle strength development in EDL and soleus muscle, decreases fatigue, reduces cholesterol and triglyceride concentrations and improves oxidative stress parameters such as TBARS, ROS, and glutathione status.
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Affiliation(s)
- Manuel Alejandro Vargas-Vargas
- Instituto de Investigaciones Químico-Biológicas, Universidad Michoacana de San Nicolás de Hidalgo, Francisco J. Múgica S/N, Col. Felicitas del Río, 58030, Morelia, Michoacán, México
| | - Alfredo Saavedra-Molina
- Instituto de Investigaciones Químico-Biológicas, Universidad Michoacana de San Nicolás de Hidalgo, Francisco J. Múgica S/N, Col. Felicitas del Río, 58030, Morelia, Michoacán, México
| | - Mariana Gómez-Barroso
- Instituto de Investigaciones Químico-Biológicas, Universidad Michoacana de San Nicolás de Hidalgo, Francisco J. Múgica S/N, Col. Felicitas del Río, 58030, Morelia, Michoacán, México
| | - Donovan Peña-Montes
- Instituto de Investigaciones Químico-Biológicas, Universidad Michoacana de San Nicolás de Hidalgo, Francisco J. Múgica S/N, Col. Felicitas del Río, 58030, Morelia, Michoacán, México
| | - Christian Cortés-Rojo
- Instituto de Investigaciones Químico-Biológicas, Universidad Michoacana de San Nicolás de Hidalgo, Francisco J. Múgica S/N, Col. Felicitas del Río, 58030, Morelia, Michoacán, México
| | - Alain R Rodríguez-Orozco
- Facultad de Ciencias Médicas y Biológicas "Dr. Ignacio Chávez", Universidad Michoacana de San Nicolás de Hidalgo, Av. Dr. Rafael Carrillo S/N, Esq. Dr. Salvador González Herrejón Bosque, 58020, 58000, Cuauhtémoc, Morelia, Michoacán, México
| | - Montoya-Pérez Rocío
- Instituto de Investigaciones Químico-Biológicas, Universidad Michoacana de San Nicolás de Hidalgo, Francisco J. Múgica S/N, Col. Felicitas del Río, 58030, Morelia, Michoacán, México.
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Tsentsevitsky AN, Gafurova CR, Petrov AM. KATP channels as ROS-dependent modulator of neurotransmitter release at the neuromuscular junctions. Life Sci 2022; 310:121120. [DOI: 10.1016/j.lfs.2022.121120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2022] [Revised: 10/12/2022] [Accepted: 10/20/2022] [Indexed: 11/09/2022]
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6
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Morris CE, Wheeler JJ, Joos B. The Donnan-dominated resting state of skeletal muscle fibers contributes to resilience and longevity in dystrophic fibers. J Gen Physiol 2022; 154:212743. [PMID: 34731883 PMCID: PMC8570295 DOI: 10.1085/jgp.202112914] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2021] [Accepted: 09/30/2021] [Indexed: 11/28/2022] Open
Abstract
Duchenne muscular dystrophy (DMD) is an X-linked dystrophin-minus muscle-wasting disease. Ion homeostasis in skeletal muscle fibers underperforms as DMD progresses. But though DMD renders these excitable cells intolerant of exertion, sodium overloaded, depolarized, and spontaneously contractile, they can survive for several decades. We show computationally that underpinning this longevity is a strikingly frugal, robust Pump-Leak/Donnan (P-L/D) ion homeostatic process. Unlike neurons, which operate with a costly “Pump-Leak–dominated” ion homeostatic steady state, skeletal muscle fibers operate with a low-cost “Donnan-dominated” ion homeostatic steady state that combines a large chloride permeability with an exceptionally small sodium permeability. Simultaneously, this combination keeps fiber excitability low and minimizes pump expenditures. As mechanically active, long-lived multinucleate cells, skeletal muscle fibers have evolved to handle overexertion, sarcolemmal tears, ischemic bouts, etc.; the frugality of their Donnan dominated steady state lets them maintain the outsized pump reserves that make them resilient during these inevitable transient emergencies. Here, P-L/D model variants challenged with DMD-type insult/injury (low pump-strength, overstimulation, leaky Nav and cation channels) show how chronic “nonosmotic” sodium overload (observed in DMD patients) develops. Profoundly severe DMD ion homeostatic insult/injury causes spontaneous firing (and, consequently, unwanted excitation–contraction coupling) that elicits cytotoxic swelling. Therefore, boosting operational pump-strength and/or diminishing sodium and cation channel leaks should help extend DMD fiber longevity.
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Affiliation(s)
- Catherine E Morris
- Neuroscience, Ottawa Hospital Research Institute, Ottawa, Canada.,Center for Neural Dynamics, University of Ottawa, Ottawa, Canada
| | | | - Béla Joos
- Center for Neural Dynamics, University of Ottawa, Ottawa, Canada.,Department of Physics, University of Ottawa, Ottawa, Canada
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7
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Scala R, Maqoud F, Zizzo N, Passantino G, Mele A, Camerino GM, McClenaghan C, Harter TM, Nichols CG, Tricarico D. Consequences of SUR2[A478V] Mutation in Skeletal Muscle of Murine Model of Cantu Syndrome. Cells 2021; 10:cells10071791. [PMID: 34359961 PMCID: PMC8307364 DOI: 10.3390/cells10071791] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2021] [Revised: 07/12/2021] [Accepted: 07/13/2021] [Indexed: 12/18/2022] Open
Abstract
(1) Background: Cantu syndrome (CS) arises from gain-of-function (GOF) mutations in the ABCC9 and KCNJ8 genes, which encode ATP-sensitive K+ (KATP) channel subunits SUR2 and Kir6.1, respectively. Most CS patients have mutations in SUR2, the major component of skeletal muscle KATP, but the consequences of SUR2 GOF in skeletal muscle are unknown. (2) Methods: We performed in vivo and ex vivo characterization of skeletal muscle in heterozygous SUR2[A478V] (SUR2wt/AV) and homozygous SUR2[A478V] (SUR2AV/AV) CS mice. (3) Results: In SUR2wt/AV and SUR2AV/AV mice, forelimb strength and diaphragm amplitude movement were reduced; muscle echodensity was enhanced. KATP channel currents recorded in Flexor digitorum brevis fibers showed reduced MgATP-sensitivity in SUR2wt/AV, dramatically so in SUR2AV/AV mice; IC50 for MgATP inhibition of KATP currents were 1.9 ± 0.5 × 10−5 M in SUR2wt/AV and 8.6 ± 0.4 × 10−6 M in WT mice and was not measurable in SUR2AV/AV. A slight rightward shift of sensitivity to inhibition by glibenclamide was detected in SUR2AV/AV mice. Histopathological and qPCR analysis revealed atrophy of soleus and tibialis anterior muscles and up-regulation of atrogin-1 and MuRF1 mRNA in CS mice. (4) Conclusions: SUR2[A478V] “knock-in” mutation in mice impairs KATP channel modulation by MgATP, markedly so in SUR2AV/AV, with atrophy and non-inflammatory edema in different skeletal muscle phenotypes.
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Affiliation(s)
- Rosa Scala
- Section of Pharmacology, Department of Pharmacy-Pharmaceutical Sciences, University of Bari “Aldo Moro”, 70125 Bari, Italy; (R.S.); (F.M.); (A.M.); (G.M.C.)
| | - Fatima Maqoud
- Section of Pharmacology, Department of Pharmacy-Pharmaceutical Sciences, University of Bari “Aldo Moro”, 70125 Bari, Italy; (R.S.); (F.M.); (A.M.); (G.M.C.)
| | - Nicola Zizzo
- Section of Veterinary Pathology and Comparative Oncology, Department of Veterinary Medicine, University of Bari “Aldo Moro”, 70121 Bari, Italy; (N.Z.); (G.P.)
| | - Giuseppe Passantino
- Section of Veterinary Pathology and Comparative Oncology, Department of Veterinary Medicine, University of Bari “Aldo Moro”, 70121 Bari, Italy; (N.Z.); (G.P.)
| | - Antonietta Mele
- Section of Pharmacology, Department of Pharmacy-Pharmaceutical Sciences, University of Bari “Aldo Moro”, 70125 Bari, Italy; (R.S.); (F.M.); (A.M.); (G.M.C.)
| | - Giulia Maria Camerino
- Section of Pharmacology, Department of Pharmacy-Pharmaceutical Sciences, University of Bari “Aldo Moro”, 70125 Bari, Italy; (R.S.); (F.M.); (A.M.); (G.M.C.)
| | - Conor McClenaghan
- Center for the Investigation of Membrane Excitability Diseases, Department of Cell Biology and Physiology, Washington University School of Medicine, St. Louis, MO 63110-1010, USA; (C.M.); (T.M.H.); (C.G.N.)
| | - Theresa M. Harter
- Center for the Investigation of Membrane Excitability Diseases, Department of Cell Biology and Physiology, Washington University School of Medicine, St. Louis, MO 63110-1010, USA; (C.M.); (T.M.H.); (C.G.N.)
| | - Colin G. Nichols
- Center for the Investigation of Membrane Excitability Diseases, Department of Cell Biology and Physiology, Washington University School of Medicine, St. Louis, MO 63110-1010, USA; (C.M.); (T.M.H.); (C.G.N.)
| | - Domenico Tricarico
- Section of Pharmacology, Department of Pharmacy-Pharmaceutical Sciences, University of Bari “Aldo Moro”, 70125 Bari, Italy; (R.S.); (F.M.); (A.M.); (G.M.C.)
- Correspondence:
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8
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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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9
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Gómez-Barroso M, Moreno-Calderón KM, Sánchez-Duarte E, Cortés-Rojo C, Saavedra-Molina A, Rodríguez-Orozco AR, Montoya-Pérez R. Diazoxide and Exercise Enhance Muscle Contraction during Obesity by Decreasing ROS Levels, Lipid Peroxidation, and Improving Glutathione Redox Status. Antioxidants (Basel) 2020; 9:antiox9121232. [PMID: 33291828 PMCID: PMC7762033 DOI: 10.3390/antiox9121232] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2020] [Revised: 11/26/2020] [Accepted: 12/02/2020] [Indexed: 12/16/2022] Open
Abstract
Obesity causes insulin resistance and hyperinsulinemia which causes skeletal muscle dysfunction resulting in a decrease in contraction force and a reduced capacity to avoid fatigue, which overall, causes an increase in oxidative stress. KATP channel openers such as diazoxide and the implementation of exercise protocols have been reported to be actively involved in protecting skeletal muscle against metabolic stress; however, the effects of diazoxide and exercise on muscle contraction and oxidative stress during obesity have not been explored. This study aimed to determine the effect of diazoxide in the contraction of skeletal muscle of obese male Wistar rats (35 mg/kg), and with an exercise protocol (five weeks) and the combination from both. Results showed that the treatment with diazoxide and exercise improved muscular contraction, showing an increase in maximum tension and total tension due to decreased ROS and lipid peroxidation levels and improved glutathione redox state. Therefore, these results suggest that diazoxide and exercise improve muscle function during obesity, possibly through its effects as KATP channel openers.
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Affiliation(s)
- Mariana Gómez-Barroso
- Instituto de Investigaciones Químico-Biológicas, Universidad Michoacana de San Nicolás de Hidalgo, Francisco J. Múgica S/N, Col. Felicitas del Río, Morelia, Michoacán 58030, Mexico; (M.G.-B.); (K.M.M.-C.); (C.C.-R.); (A.S.-M.)
| | - Koré M. Moreno-Calderón
- Instituto de Investigaciones Químico-Biológicas, Universidad Michoacana de San Nicolás de Hidalgo, Francisco J. Múgica S/N, Col. Felicitas del Río, Morelia, Michoacán 58030, Mexico; (M.G.-B.); (K.M.M.-C.); (C.C.-R.); (A.S.-M.)
| | - Elizabeth Sánchez-Duarte
- Departamento de Ciencias Aplicadas al Trabajo, Universidad de Guanajuato Campus León, Eugenio Garza Sada 572, Lomas del Campestre Sección 2, León, Guanajuato 37150, Mexico;
| | - Christian Cortés-Rojo
- Instituto de Investigaciones Químico-Biológicas, Universidad Michoacana de San Nicolás de Hidalgo, Francisco J. Múgica S/N, Col. Felicitas del Río, Morelia, Michoacán 58030, Mexico; (M.G.-B.); (K.M.M.-C.); (C.C.-R.); (A.S.-M.)
| | - Alfredo Saavedra-Molina
- Instituto de Investigaciones Químico-Biológicas, Universidad Michoacana de San Nicolás de Hidalgo, Francisco J. Múgica S/N, Col. Felicitas del Río, Morelia, Michoacán 58030, Mexico; (M.G.-B.); (K.M.M.-C.); (C.C.-R.); (A.S.-M.)
| | - Alain R. Rodríguez-Orozco
- Facultad de Ciencias Médicas y Biológicas “Dr. Ignacio Chávez”, Universidad Michoacana de San Nicolás de Hidalgo Av. Dr. Rafael Carrillo S/N, Esq. Dr. Salvador González Herrejón, Bosque Cuauhtémoc, Morelia, Michoacán 58020, Mexico;
| | - Rocío Montoya-Pérez
- Instituto de Investigaciones Químico-Biológicas, Universidad Michoacana de San Nicolás de Hidalgo, Francisco J. Múgica S/N, Col. Felicitas del Río, Morelia, Michoacán 58030, Mexico; (M.G.-B.); (K.M.M.-C.); (C.C.-R.); (A.S.-M.)
- Correspondence:
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10
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Scala R, Maqoud F, Zizzo N, Mele A, Camerino GM, Zito FA, Ranieri G, McClenaghan C, Harter TM, Nichols CG, Tricarico D. Pathophysiological Consequences of KATP Channel Overactivity and Pharmacological Response to Glibenclamide in Skeletal Muscle of a Murine Model of Cantù Syndrome. Front Pharmacol 2020; 11:604885. [PMID: 33329006 PMCID: PMC7734337 DOI: 10.3389/fphar.2020.604885] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2020] [Accepted: 11/03/2020] [Indexed: 12/11/2022] Open
Abstract
Cantù syndrome (CS) arises from mutations in ABCC9 and KCNJ8 genes that lead to gain of function (GOF) of ATP-sensitive potassium (KATP) channels containing SUR2A and Kir6.1 subunits, respectively, of KATP channels. Pathological consequences of CS have been reported for cardiac and smooth muscle cells but consequences in skeletal muscle are unknown. Children with CS show muscle hypotonia and adult manifest fatigability. We analyzed muscle properties of Kir6.1[V65M] CS mice, by measurements of forelimb strength and ultrasonography of hind-limb muscles, as well as assessing KATP channel properties in native Flexor digitorum brevis (FDB) and Soleus (SOL) fibers by the patch-clamp technique in parallel with histopathological, immunohistochemical and Polymerase Chain Reaction (PCR) analysis. Forelimb strength was lower in Kir6.1wt/VM mice than in WT mice. Also, a significant enhancement of echodensity was observed in hind-limb muscles of Kir6.1wt/VM mice relative to WT, suggesting the presence of fibrous tissue. There was a higher KATP channel current amplitude in Kir6.1wt/VM FDB fibers relative to WT and a reduced response to glibenclamide. The IC50 of glibenclamide to block KATP channels in FDB fibers was 1.3 ± 0.2 × 10−7 M in WT and 1.2 ± 0.1 × 10−6 M in Kir6.1wt/VM mice, respectively; and it was 1.2 ± 0.4 × 10−7 M in SOL WT fibers but not measurable in Kir6.1wt/VM fibers. The sensitivity of the KATP channel to MgATP was not modified in Kir6.1wt/VM fibers. Histopathological/immunohistochemical analysis of SOL revealed degeneration plus regressive-necrotic lesions with regeneration, and up-regulation of Atrogin-1, MuRF1, and BNIP3 mRNA/proteins in Kir6.1wt/VM mice. Kir6.1wt/VM mutation in skeletal muscle leads to changes of the KATP channel response to glibenclamide in FDB and SOL fibers, and it is associated with histopathological and gene expression changes in slow-twitch muscle, suggesting marked atrophy and autophagy.
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Affiliation(s)
- Rosa Scala
- Section of Pharmacology, Department of Pharmacy-Pharmaceutical Sciences, University of Bari "Aldo Moro", Bari, Italy
| | - Fatima Maqoud
- Section of Pharmacology, Department of Pharmacy-Pharmaceutical Sciences, University of Bari "Aldo Moro", Bari, Italy
| | - Nicola Zizzo
- Section of Veterinary Pathology and Comparative Oncology, Department of Veterinary Medicine, University of Bari "Aldo Moro", Valenzano, Italy
| | - Antonietta Mele
- Section of Pharmacology, Department of Pharmacy-Pharmaceutical Sciences, University of Bari "Aldo Moro", Bari, Italy
| | - Giulia Maria Camerino
- Section of Pharmacology, Department of Pharmacy-Pharmaceutical Sciences, University of Bari "Aldo Moro", Bari, Italy
| | - Francesco Alfredo Zito
- Interventional and Medical Oncology Unit, Department of Pathology National Cancer Research Centre, IRCCS Istituto Tumori Giovanni Paolo II, Bari, Italy
| | - Girolamo Ranieri
- Interventional and Medical Oncology Unit, Department of Pathology National Cancer Research Centre, IRCCS Istituto Tumori Giovanni Paolo II, Bari, Italy
| | - Conor McClenaghan
- Department of Cell Biology and Physiology, and Center for the Investigation of Membrane Excitability Diseases, Washington University School of Medicine, St. Louis, MO, United States
| | - Theresa M Harter
- Department of Cell Biology and Physiology, and Center for the Investigation of Membrane Excitability Diseases, Washington University School of Medicine, St. Louis, MO, United States
| | - Colin G Nichols
- Department of Cell Biology and Physiology, and Center for the Investigation of Membrane Excitability Diseases, Washington University School of Medicine, St. Louis, MO, United States
| | - Domenico Tricarico
- Section of Pharmacology, Department of Pharmacy-Pharmaceutical Sciences, University of Bari "Aldo Moro", Bari, Italy
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Tarpey MD, Amorese AJ, Balestrieri NP, Ryan TE, Schmidt CA, McClung JM, Spangenburg EE. Characterization and utilization of the flexor digitorum brevis for assessing skeletal muscle function. Skelet Muscle 2018; 8:14. [PMID: 29665848 PMCID: PMC5905177 DOI: 10.1186/s13395-018-0160-3] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2018] [Accepted: 04/03/2018] [Indexed: 12/25/2022] Open
Abstract
BACKGROUND The ability to assess skeletal muscle function and delineate regulatory mechanisms is essential to uncovering therapeutic approaches that preserve functional independence in a disease state. Skeletal muscle provides distinct experimental challenges due to inherent differences across muscle groups, including fiber type and size that may limit experimental approaches. The flexor digitorum brevis (FDB) possesses numerous properties that offer the investigator a high degree of experimental flexibility to address specific hypotheses. To date, surprisingly few studies have taken advantage of the FDB to investigate mechanisms regulating skeletal muscle function. The purpose of this study was to characterize and experimentally demonstrate the value of the FDB muscle for scientific investigations. METHODS First, we characterized the FDB phenotype and provide reference comparisons to skeletal muscles commonly used in the field. We developed approaches allowing for experimental assessment of force production, in vitro and in vivo microscopy, and mitochondrial respiration to demonstrate the versatility of the FDB. As proof-of principle, we performed experiments to alter force production or mitochondrial respiration to validate the flexibility the FDB affords the investigator. RESULTS The FDB is made up of small predominantly type IIa and IIx fibers that collectively produce less peak isometric force than the extensor digitorum longus (EDL) or soleus muscles, but demonstrates a greater fatigue resistance than the EDL. Unlike the other muscles, inherent properties of the FDB muscle make it amenable to multiple in vitro- and in vivo-based microscopy methods. Due to its anatomical location, the FDB can be used in cardiotoxin-induced muscle injury protocols and is amenable to electroporation of cDNA with a high degree of efficiency allowing for an effective means of genetic manipulation. Using a novel approach, we also demonstrate methods for assessing mitochondrial respiration in the FDB, which are comparable to the commonly used gastrocnemius muscle. As proof of principle, short-term overexpression of Pgc1α in the FDB increased mitochondrial respiration rates. CONCLUSION The results highlight the experimental flexibility afforded the investigator by using the FDB muscle to assess mechanisms that regulate skeletal muscle function.
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Affiliation(s)
- Michael D. Tarpey
- Department of Physiology, Brody School of Medicine, East Carolina University, Greenville, NC 27834 USA
| | - Adam J. Amorese
- Department of Physiology, Brody School of Medicine, East Carolina University, Greenville, NC 27834 USA
| | - Nicholas P. Balestrieri
- Department of Physiology, Brody School of Medicine, East Carolina University, Greenville, NC 27834 USA
| | - Terence E. Ryan
- Department of Physiology, Brody School of Medicine, East Carolina University, Greenville, NC 27834 USA
| | - Cameron A. Schmidt
- Department of Physiology, Brody School of Medicine, East Carolina University, Greenville, NC 27834 USA
| | - Joseph M. McClung
- Department of Physiology, Brody School of Medicine, East Carolina University, Greenville, NC 27834 USA
- East Carolina Diabetes and Obesity Institute, East Carolina University, Greenville, NC 27834 USA
| | - Espen E. Spangenburg
- Department of Physiology, Brody School of Medicine, East Carolina University, Greenville, NC 27834 USA
- East Carolina Diabetes and Obesity Institute, East Carolina University, Greenville, NC 27834 USA
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Youssef N, Campbell S, Barr A, Gandhi M, Hunter B, Dolinsky V, Dyck JRB, Clanachan AS, Light PE. Hearts lacking plasma membrane KATP channels display changes in basal aerobic metabolic substrate preference and AMPK activity. Am J Physiol Heart Circ Physiol 2017; 313:H469-H478. [DOI: 10.1152/ajpheart.00612.2016] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/09/2016] [Revised: 06/13/2017] [Accepted: 06/13/2017] [Indexed: 12/12/2022]
Abstract
Cardiac ATP-sensitive K+ (KATP) channels couple changes in cellular metabolism to membrane excitability and are activated during metabolic stress, although under basal aerobic conditions, KATP channels are thought to be predominately closed. Despite intense research into the roles of KATP channels during metabolic stress, their contribution to aerobic basal cardiac metabolism has not been previously investigated. Hearts from Kir6.2+/+ and Kir6.2−/− mice were perfused in working mode, and rates of glycolysis, fatty acid oxidation, and glucose oxidation were measured. Changes in activation/expression of proteins regulating metabolism were probed by Western blot analysis. Despite cardiac mechanical function and metabolic efficiency being similar in both groups, hearts from Kir6.2−/− mice displayed an approximately twofold increase in fatty acid oxidation and a 0.45-fold reduction in glycolytic rates but similar glucose oxidation rates compared with hearts from Kir6.2+/+ mice. Kir6.2−/− hearts also possessed elevated levels of activated AMP-activated protein kinase (AMPK), higher glycogen content, and reduced mitochondrial density. Moreover, activation of AMPK by isoproterenol or diazoxide was significantly blunted in Kir6.2−/− hearts. These data indicate that KATP channel ablation alters aerobic basal cardiac metabolism. The observed increase in fatty acid oxidation and decreased glycolysis before any metabolic insult may contribute to the poor recovery observed in Kir6.2−/− hearts in response to exercise or ischemia-reperfusion injury. Therefore, KATP channels may play an important role in the regulation of cardiac metabolism through AMPK signaling. NEW & NOTEWORTHY In this study, we show that genetic ablation of plasma membrane ATP-sensitive K+ channels results in pronounced changes in cardiac metabolic substrate preference and AMP-activated protein kinase activity. These results suggest that ATP-sensitive K+ channels may play a novel role in regulating metabolism in addition to their well-documented effects on ionic homeostasis during periods of stress.
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Affiliation(s)
- Nermeen Youssef
- Department of Pharmacology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada
| | - Scott Campbell
- Department of Pharmacology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada
| | - Amy Barr
- Department of Pharmacology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada
| | - Manoj Gandhi
- Department of Pharmacology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada
| | - Beth Hunter
- Department of Pharmacology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada
| | - Vernon Dolinsky
- Children’s Hospital Research Institute of Manitoba, Department of Pharmacology and Therapeutics, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Jason R. B. Dyck
- Department of Pediatrics, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada; and
| | - Alexander S. Clanachan
- Department of Pharmacology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada
| | - Peter E. Light
- Department of Pharmacology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada
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