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Inoue T, Hashimoto M, Katakura M, Tanabe Y, Al Mamun A, Matsuzaki K, Otani H, Shido O. Effects of chronic administration of arachidonic acid on lipid profiles and morphology in the skeletal muscles of aged rats. Prostaglandins Leukot Essent Fatty Acids 2014; 91:119-27. [PMID: 25128088 DOI: 10.1016/j.plefa.2014.07.015] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/14/2014] [Revised: 07/19/2014] [Accepted: 07/21/2014] [Indexed: 01/21/2023]
Abstract
Arachidonic acid (20:4n-6, ARA) is a major component of the cell membrane, whereas ARA-derived eicosanoids are formed when cells are damaged. Aging is associated with an accretion of oxidative stress in skeletal muscles. In this study, we examined the effects of chronic administration (13 weeks) of ARA (240 mg/kg/day) on fatty acid composition, antioxidative status, and morphology of slow (soleus muscles) and fast (extensor digitorum longus muscles; EDL)-twitch muscles in aged rats (21 months old). The level of reactive oxygen species was higher in the EDL of ARA-administered rats than in that of control rats. ARA administration decreased the muscle cell volumes and increased the number of slow myosin heavy chain (MHC)-positive cells in the EDL. The relative content of MHC2X was increased whereas the relative content of MHC2B was decreased in the EDL of ARA-administered rats. These results suggest that ARA deposition in the fast-twitch muscle of aged rats reduced cell volume with an increase in oxidative stress.
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Affiliation(s)
- Takayuki Inoue
- Department of Environmental Physiology, Faculty of Medicine, Shimane University, 89-1 Enya-cho, Izumo, Shimane 693-8501, Japan; Department of Developmental Biology, Faculty of Medicine, Shimane University, 89-1 Enya-cho, Izumo, Shimane 693-8501, Japan
| | - Michio Hashimoto
- Department of Environmental Physiology, Faculty of Medicine, Shimane University, 89-1 Enya-cho, Izumo, Shimane 693-8501, Japan.
| | - Masanori Katakura
- Department of Environmental Physiology, Faculty of Medicine, Shimane University, 89-1 Enya-cho, Izumo, Shimane 693-8501, Japan
| | - Yoko Tanabe
- Department of Environmental Physiology, Faculty of Medicine, Shimane University, 89-1 Enya-cho, Izumo, Shimane 693-8501, Japan
| | - Abdullah Al Mamun
- Department of Environmental Physiology, Faculty of Medicine, Shimane University, 89-1 Enya-cho, Izumo, Shimane 693-8501, Japan
| | - Kentaro Matsuzaki
- Department of Environmental Physiology, Faculty of Medicine, Shimane University, 89-1 Enya-cho, Izumo, Shimane 693-8501, Japan
| | - Hiroki Otani
- Department of Developmental Biology, Faculty of Medicine, Shimane University, 89-1 Enya-cho, Izumo, Shimane 693-8501, Japan
| | - Osamu Shido
- Department of Environmental Physiology, Faculty of Medicine, Shimane University, 89-1 Enya-cho, Izumo, Shimane 693-8501, Japan
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Miller MS, Callahan DM, Toth MJ. Skeletal muscle myofilament adaptations to aging, disease, and disuse and their effects on whole muscle performance in older adult humans. Front Physiol 2014; 5:369. [PMID: 25309456 PMCID: PMC4176476 DOI: 10.3389/fphys.2014.00369] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2014] [Accepted: 09/07/2014] [Indexed: 12/02/2022] Open
Abstract
Skeletal muscle contractile function declines with aging, disease, and disuse. In vivo muscle contractile function depends on a variety of factors, but force, contractile velocity and power generating capacity ultimately derive from the summed contribution of single muscle fibers. The contractile performance of these fibers are, in turn, dependent upon the isoform and function of myofilament proteins they express, with myosin protein expression and its mechanical and kinetic characteristics playing a predominant role. Alterations in myofilament protein biology, therefore, may contribute to the development of functional limitations and disability in these conditions. Recent studies suggest that these conditions are associated with altered single fiber performance due to decreased expression of myofilament proteins and/or changes in myosin-actin cross-bridge interactions. Furthermore, cellular and myofilament-level adaptations are related to diminished whole muscle and whole body performance. Notably, the effect of these various conditions on myofilament and single fiber function tends to be larger in older women compared to older men, which may partially contribute to their higher rates of disability. To maintain functionality and provide the most appropriate and effective countermeasures to aging, disease, and disuse in both sexes, a more thorough understanding is needed of the contribution of myofilament adaptations to functional disability in older men and women and their contribution to tissue level function and mobility impairment.
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Affiliation(s)
- Mark S Miller
- Department of Kinesiology, School of Public Health and Health Sciences, University of Massachusetts Amherst, MA, USA
| | - Damien M Callahan
- Department of Molecular Physiology and Biophysics, College of Medicine, University of Vermont Burlington, VT, USA
| | - Michael J Toth
- Department of Molecular Physiology and Biophysics, College of Medicine, University of Vermont Burlington, VT, USA ; Department of Medicine, College of Medicine, University of Vermont Burlington, VT, USA
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53
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Petersen JL, Valberg SJ, Mickelson JR, McCue ME. Haplotype diversity in the equine myostatin gene with focus on variants associated with race distance propensity and muscle fiber type proportions. Anim Genet 2014; 45:827-35. [PMID: 25160752 DOI: 10.1111/age.12205] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/04/2014] [Indexed: 12/21/2022]
Abstract
Two variants in the equine myostatin gene (MSTN), including a T/C SNP in the first intron and a 227-bp SINE insertion in the promoter, are associated with muscle fiber type proportions in the Quarter Horse (QH) and with the prediction of race distance propensity in the Thoroughbred (TB). Genotypes from these loci, along with 18 additional variants surrounding MSTN, were examined in 301 horses of 14 breeds to evaluate haplotype relationships and diversity. The C allele of intron 1 was found in 12 of 14 breeds at a frequency of 0.27; the SINE was observed in five breeds, but common in only the TB and QH (0.73 and 0.48 respectively). Haplotype data suggest the SINE insertion is contemporary to and arose upon a haplotype containing the intron 1 C allele. Gluteal muscle biopsies of TBs showed a significant association of the intron 1 C allele and SINE with a higher proportion of Type 2B and lower proportion of Type 1 fibers. However, in the Belgian horse, in which the SINE is not present, the intron 1 SNP was not associated with fiber type proportions, and evaluation of fiber type proportions across the Belgian, TB and QH breeds shows the significant effect of breed on fiber type proportions is negated when evaluating horses without the SINE variant. These data suggest the SINE, rather than the intron 1 SNP, is driving the observed muscle fiber type characteristics and is the variant targeted by selection for short-distance racing.
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Affiliation(s)
- Jessica L Petersen
- Veterinary Population Medicine, University of Minnesota, St Paul, MN, 55108, USA; Department of Animal Science, University of Nebraska, Lincoln, NE, 68583-0908, USA
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Effect of exercise intensity on isoform-specific expressions of NT-PGC-1 α mRNA in mouse skeletal muscle. BIOMED RESEARCH INTERNATIONAL 2014; 2014:402175. [PMID: 25136584 PMCID: PMC4106048 DOI: 10.1155/2014/402175] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/05/2014] [Revised: 04/02/2014] [Accepted: 04/28/2014] [Indexed: 11/17/2022]
Abstract
PGC-1α is an inducible transcriptional coactivator that regulates mitochondrial biogenesis and cellular energy metabolism in skeletal muscle. Recent studies have identified two additional PGC-1α transcripts that are derived from an alternative exon 1 (exon 1b) and induced by exercise. Given that the PGC-1α gene also produces NT-PGC-1α transcript by alternative 3′ splicing between exon 6 and exon 7, we have investigated isoform-specific expression of NT-PGC-1α mRNA in mouse skeletal muscle during physical exercise with different intensities. We report here that NT-PGC-1α-a mRNA expression derived from a canonical exon 1 (exon 1a) is increased by high-intensity exercise and AMPK activator AICAR in mouse skeletal muscle but not altered by low- and medium-intensity exercise and β2-adrenergic receptor agonist clenbuterol. In contrast, the alternative exon 1b-driven NT-PGC-1α-b (PGC-1α4) and NT-PGC-1α-c are highly induced by low-, medium-, and high-intensity exercise, AICAR, and clenbuterol. Ectopic expression of NT-PGC-1α-a in C2C12 myotube cells upregulates myosin heavy chain (MHC I, MHC II a) and Glut4, which represent oxidative fibers, and promotes the expression of mitochondrial genes (Cyc1, COX5B, and ATP5B). In line with gene expression data, citrate synthase activity was significantly increased by NT-PGC-1α-a in C2C12 myotube cells. Our results indicate the regulatory role for NT-PGC-1α-a in mitochondrial biogenesis and adaptation of skeletal muscle to endurance exercise.
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Ferraro E, Giammarioli AM, Chiandotto S, Spoletini I, Rosano G. Exercise-induced skeletal muscle remodeling and metabolic adaptation: redox signaling and role of autophagy. Antioxid Redox Signal 2014; 21:154-76. [PMID: 24450966 PMCID: PMC4048572 DOI: 10.1089/ars.2013.5773] [Citation(s) in RCA: 133] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
SIGNIFICANCE Skeletal muscle is a highly plastic tissue. Exercise evokes signaling pathways that strongly modify myofiber metabolism and physiological and contractile properties of skeletal muscle. Regular physical activity is beneficial for health and is highly recommended for the prevention of several chronic conditions. In this review, we have focused our attention on the pathways that are known to mediate physical training-induced plasticity. RECENT ADVANCES An important role for redox signaling has recently been proposed in exercise-mediated muscle remodeling and peroxisome proliferator-activated receptor γ (PPARγ) coactivator-1α (PGC-1α) activation. Still more currently, autophagy has also been found to be involved in metabolic adaptation to exercise. CRITICAL ISSUES Both redox signaling and autophagy are processes with ambivalent effects; they can be detrimental and beneficial, depending on their delicate balance. As such, understanding their role in the chain of events induced by exercise and leading to skeletal muscle remodeling is a very complicated matter. Moreover, the study of the signaling induced by exercise is made even more difficult by the fact that exercise can be performed with several different modalities, with this having different repercussions on adaptation. FUTURE DIRECTIONS Unraveling the complexity of the molecular signaling triggered by exercise on skeletal muscle is crucial in order to define the therapeutic potentiality of physical training and to identify new pharmacological compounds that are able to reproduce some beneficial effects of exercise. In evaluating the effect of new "exercise mimetics," it will also be necessary to take into account the involvement of reactive oxygen species, reactive nitrogen species, and autophagy and their controversial effects.
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Affiliation(s)
- Elisabetta Ferraro
- 1 Pathophysiology and Treatment of Muscle Wasting Disorders Unit, IRCCS San Raffaele Pisana , Rome, Italy
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56
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Muscle-type specific autophosphorylation of CaMKII isoforms after paced contractions. BIOMED RESEARCH INTERNATIONAL 2014; 2014:943806. [PMID: 25054156 PMCID: PMC4099113 DOI: 10.1155/2014/943806] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/06/2014] [Accepted: 05/27/2014] [Indexed: 01/17/2023]
Abstract
We explored to what extent isoforms of the regulator of excitation-contraction and excitation-transcription coupling, calcium/calmodulin protein kinase II (CaMKII) contribute to the specificity of myocellular calcium sensing between muscle types and whether concentration transients in its autophosphorylation can be simulated. CaMKII autophosphorylation at Thr287 was assessed in three muscle compartments of the rat after slow or fast motor unit-type stimulation and was compared against a computational model (CaMuZclE) coupling myocellular calcium dynamics with CaMKII Thr287 phosphorylation. Qualitative differences existed between fast- (gastrocnemius medialis) and slow-type muscle (soleus) for the expression pattern of CaMKII isoforms. Phospho-Thr287 content of δA CaMKII, associated with nuclear functions, demonstrated a transient and compartment-specific increase after excitation, which contrasted to the delayed autophosphorylation of the sarcoplasmic reticulum-associated βM CaMKII. In soleus muscle, excitation-induced δA CaMKII autophosphorylation demonstrated frequency dependence (P = 0.02). In the glycolytic compartment of gastrocnemius medialis, CaMKII autophosphorylation after excitation was blunted. In silico assessment emphasized the importance of mitochondrial calcium buffer capacity for excitation-induced CaMKII autophosphorylation but did not predict its isoform specificity. The findings expose that CaMKII autophosphorylation with paced contractions is regulated in an isoform and muscle type-specific fashion and highlight properties emerging for phenotype-specific regulation of CaMKII.
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Song Y, Karisnan K, Noble PB, Berry CA, Lavin T, Moss TJM, Bakker AJ, Pinniger GJ, Pillow JJ. In utero LPS exposure impairs preterm diaphragm contractility. Am J Respir Cell Mol Biol 2013; 49:866-74. [PMID: 23795611 DOI: 10.1165/rcmb.2013-0107oc] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Preterm birth is associated with inflammation of the fetal membranes (chorioamnionitis). We aimed to establish how chorioamnionitis affects the contractile function and phenotype of the preterm diaphragm. Pregnant ewes received intra-amniotic injections of saline or 10 mg LPS, 2 days or 7 days before delivery at 121 days of gestation (term = 150 d). Diaphragm strips were dissected for the assessment of contractile function after terminal anesthesia. The inflammatory cytokine response, myosin heavy chain (MHC) fibers, proteolytic pathways, and intracellular molecular signaling were analyzed using quantitative PCR, ELISA, immunofluorescence staining, biochemical assays, and Western blotting. Diaphragm peak twitch force and maximal tetanic force were approximately 30% lower than control values in the 2-day and 7-day LPS groups. Activation of the NF-κB pathway, an inflammatory response, and increased proteasome activity were observed in the 2-day LPS group relative to the control or 7-day LPS group. No inflammatory response was evident after a 7-day LPS exposure. Seven-day LPS exposure markedly decreased p70S6K phosphorylation, but no effect on other signaling pathways was evident. The proportion of MHC IIa fibers was lower than that for control samples in the 7-day LPS group. MHC I fiber proportions did not differ between groups. These results demonstrate that intrauterine LPS impairs preterm diaphragmatic contractility after 2-day and 7-day exposures. Diaphragm dysfunction, resulting from 2-day LPS exposure, was associated with a transient activation of proinflammatory signaling, with subsequent increased atrophic gene expression and enhanced proteasome activity. Persistently impaired contractility for the 7-day LPS exposure was associated with the down-regulation of a key component of the protein synthetic signaling pathway and a reduction in the proportions of MHC IIa fibers.
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Affiliation(s)
- Yong Song
- 1 School of Anatomy, Physiology, and Human Biology, and
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58
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Abstract
Movement is accomplished by the controlled activation of motor unit populations. Our understanding of motor unit physiology has been derived from experimental work on the properties of single motor units and from computational studies that have integrated the experimental observations into the function of motor unit populations. The article provides brief descriptions of motor unit anatomy and muscle unit properties, with more substantial reviews of motoneuron properties, motor unit recruitment and rate modulation when humans perform voluntary contractions, and the function of an entire motor unit pool. The article emphasizes the advances in knowledge on the cellular and molecular mechanisms underlying the neuromodulation of motoneuron activity and attempts to explain the discharge characteristics of human motor units in terms of these principles. A major finding from this work has been the critical role of descending pathways from the brainstem in modulating the properties and activity of spinal motoneurons. Progress has been substantial, but significant gaps in knowledge remain.
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Affiliation(s)
- C J Heckman
- Northwestern University, Evanston, Illinois, USA.
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59
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Kohn TA, Noakes TD. Lion (Panthera leo) and caracal (Caracal caracal) type IIx single muscle fibre force and power exceed that of trained humans. J Exp Biol 2013; 216:960-9. [PMID: 23155088 PMCID: PMC3587382 DOI: 10.1242/jeb.078485] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2012] [Accepted: 11/06/2012] [Indexed: 11/20/2022]
Abstract
This study investigated for the first time maximum force production, shortening velocity (Vmax) and power output in permeabilised single muscle fibres at 12°C from lion, Panthera leo (Linnaeus 1758), and caracal, Caracal caracal (Schreber 1776), and compared the values with those from human cyclists. Additionally, the use and validation of previously frozen tissue for contractile experiments is reported. Only type IIx muscle fibres were identified in the caracal sample, whereas type IIx and only two type I fibres were found in the lion sample. Only pure type I and IIa, and hybrid type IIax fibres were identified in the human samples - there were no pure type IIx fibres. Nevertheless, compared with all the human fibre types, the lion and caracal fibres were smaller (P<0.01) in cross-sectional area (human: 6194±230 μm(2), lion: 3008±151 μm(2), caracal: 2583±221 μm(2)). On average, the felid type IIx fibres produced significantly greater force (191-211 kN m(-2)) and ~3 times more power (29.0-30.3 kN m(-2) fibre lengths s(-1)) than the human IIax fibres (100-150 kN m(-2), 4-11 kN m(-2) fibre lengths s(-1)). Vmax values of the lion type IIx fibres were also higher than those of human type IIax fibres. The findings suggest that the same fibre type may differ substantially between species and potential explanations are discussed.
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Affiliation(s)
- Tertius A Kohn
- UCT/MRC Research Unit for Exercise Science and Sports Medicine, Department of Human Biology, PO Box 115, University of Cape Town, Newlands, 7725, South Africa.
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60
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Toth MJ, Miller MS, Callahan DM, Sweeny AP, Nunez I, Grunberg SM, Der-Torossian H, Couch ME, Dittus K. Molecular mechanisms underlying skeletal muscle weakness in human cancer: reduced myosin-actin cross-bridge formation and kinetics. J Appl Physiol (1985) 2013; 114:858-68. [PMID: 23412895 DOI: 10.1152/japplphysiol.01474.2012] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Many patients with cancer experience physical disability following diagnosis, although little is known about the mechanisms underlying these functional deficits. To characterize skeletal muscle adaptations to cancer in humans, we evaluated skeletal muscle structure and contractile function at the molecular, cellular, whole-muscle, and whole-body level in 11 patients with cancer (5 cachectic, 6 noncachectic) and 6 controls without disease. Patients with cancer showed a 25% reduction in knee extensor isometric torque after adjustment for muscle mass (P < 0.05), which was strongly related to diminished power output during a walking endurance test (r = 0.889; P < 0.01). At the cellular level, single fiber isometric tension was reduced in myosin heavy chain (MHC) IIA fibers (P = 0.05) in patients with cancer, which was explained by a reduction (P < 0.05) in the number of strongly bound cross-bridges. In MHC I fibers, myosin-actin cross-bridge kinetics were reduced in patients, as evidenced by an increase in myosin attachment time (P < 0.01); and reductions in another kinetic parameter, myosin rate of force production, predicted reduced knee extensor isometric torque (r = 0.689; P < 0.05). Patients with cancer also exhibited reduced mitochondrial density (-50%; P < 0.001), which was related to increased myosin attachment time in MHC I fibers (r = -0.754; P < 0.01). Finally, no group differences in myofilament protein content or ultrastructure were noted that explained the observed functional alterations. Collectively, our results suggest reductions in myofilament protein function as a potential molecular mechanism contributing to muscle weakness and physical disability in human cancer.
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Affiliation(s)
- Michael J Toth
- Department of Medicine, University of Vermont, College of Medicine, Burlington, VT, USA.
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61
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Huffman K, Zapata I, Reddish JM, Lilburn MS, Wick M. Feed restriction delays developmental fast skeletal muscle myosin heavy chain isoforms in turkey poults selected for differential growth. Poult Sci 2012; 91:3178-83. [PMID: 23155028 DOI: 10.3382/ps.2012-02367] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Genetic selection has been very successful at significantly increasing BW and breast muscle proportion in commercial broiler and turkey strains. The mechanisms of breast muscle growth in poultry and the interactive effects of nutritional status and selection are not fully understood. The hypothesis underlying the current study is that feed restriction, simply as a vehicle for controlling early growth, would delay the temporal expression pattern of neonatal (nMyHC) and adult (aMyHC) fast skeletal muscle myosin heavy chain (MyHC) isoforms in the pectoralis major muscle of turkey poults. The poultry growth model used to evaluate this hypothesis consisted of a randombred control turkey line (RBC2) that represents commercial turkeys of the 1960s and a line developed from the RBC2 by selection for BW at 16 wk of age (F line). The F line has significantly heavier breast muscles than the RBC2 concomitant with increased BW, but the proportion of breast muscle relative to BW is similar. A quantitative indirect ELISA using fast skeletal MyHC isoform specific monoclonal antibodies revealed no significant line differences in the temporal expression of posthatch fast skeletal muscle MyHC in ad libitum fed poults. Feed restriction, however, altered the temporal expression patterns of nMyHC and aMyHC in both F line and RBC2 poults compared with the poults fed ad libitum.
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Affiliation(s)
- K Huffman
- Ohio Agricultural Research and Development Center, The Ohio State University, Wooster 44691, USA
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62
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Choi SJ, Shively CA, Register TC, Feng X, Stehle J, High K, Ip E, Kritchevsky SB, Nicklas B, Delbono O. Force-generation capacity of single vastus lateralis muscle fibers and physical function decline with age in African green vervet monkeys. J Gerontol A Biol Sci Med Sci 2012; 68:258-67. [PMID: 22923428 DOI: 10.1093/gerona/gls143] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Previous studies on the contractile properties of human myofibrils reported increase, decrease, or no change with aging, perhaps due to the differences in physical activity, diet, and other factors. This study examined physical performance and contractile characteristics of myofibrils of vastus lateralis (VL) muscle in young adult and old African green vervet monkeys. Animals were offered the same diet and lived in the same enclosures during development, so we were able to examine skeletal muscle function in vivo and in vitro with fewer potential confounding factors than are typical in human research studies. Fiber atrophy alone did not account for the age-related differences in specific force and maximal power output. Regression modeling used to identify factors contributing to lower fiber force revealed that age is the strongest predictor. Our results support a detrimental effect of aging on the intrinsic force and power generation of myofilament lattice and physical performance in vervet monkeys.
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Affiliation(s)
- Seung Jun Choi
- Department of Internal Medicine, Gerontology, Wake Forest School of Medicine, Medical Center Boulevard, Winston-Salem, NC 27157, USA
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63
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Curry JW, Hohl R, Noakes TD, Kohn TA. High oxidative capacity and type IIx fibre content in springbok and fallow deer skeletal muscle suggest fast sprinters with a resistance to fatigue. ACTA ACUST UNITED AC 2012; 215:3997-4005. [PMID: 22899533 DOI: 10.1242/jeb.073684] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Some wild antelopes are fast sprinters and more resistant to fatigue than others. This study therefore investigated two wild antelope species to better understand their reported performance capability. Muscle samples collected post mortem from the vastus lateralis and longissimus lumborum of fallow deer (Dama dama) and springbok (Antidorcas marsupialis) were analysed for myosin heavy chain isoform content, citrate synthase, 3-hydroxyacyl CoA dehydrogenase, phosphofructokinase, lactate dehydrogenase and creatine kinase activities. Cross-sectional areas, fibre type and oxidative capacities of each fibre type were determined in the vastus lateralis only. The predominant fibre type in both muscle groups and species were type IIX (>50%), with springbok having more type IIX fibres than fallow deer (P<0.05). Overall cross-sectional area was not different between the two species. The metabolic pathway analyses showed high glycolytic and oxidative capacities for both species, but springbok had significantly higher CS activities than fallow deer. Large variation and overlap in oxidative capacities existed within and between the fibre types. Some type IIX fibres presented with oxidative capacities similar to those from type I and IIA fibres. The data suggest that springbok and fallow deer are able sprint at >90 and 46 km h(-1), respectively, partly from having large type IIX fibre contents and high glycolytic capacities. The high oxidative capacities also suggest that these animals may be able to withstand fatigue for long periods of time.
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Affiliation(s)
- Jennifer Wendy Curry
- UCT/MRC Research Unit for Exercise Science and Sports Medicine, Department of Human Biology, PO Box 115, Newlands, 7725, South Africa
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64
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Lin DC, Hershey JD, Mattoon JS, Robbins CT. Skeletal muscles of hibernating brown bears are unusually resistant to effects of denervation. J Exp Biol 2012; 215:2081-7. [DOI: 10.1242/jeb.066134] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
SUMMARY
Hibernating bears retain most of their skeletal muscle strength despite drastically reduced weight-bearing activity. Regular neural activation of muscles is a potential mechanism by which muscle atrophy could be limited. However, both mechanical loading and neural activity are usually necessary to maintain muscle size. An alternative mechanism is that the signaling pathways related to the regulation of muscle size could be altered so that neither mechanical nor neural inputs are needed for retaining strength. More specifically, we hypothesized that muscles in hibernating bears are resistant to a severe reduction in neural activation. To test this hypothesis, we unilaterally transected the common peroneal nerve, which innervates ankle flexor muscles, in hibernating and summer-active brown bears (Ursus arctos). In hibernating bears, the long digital extensor (LDE) and cranial tibial (CT) musculotendon masses on the denervated side decreased after 11 weeks post-surgery by 18±11 and 25±10%, respectively, compared with those in the intact side. In contrast, decreases in musculotendon masses of summer-active bears after denervation were 61±4 and 58±5% in the LDE and CT, respectively, and significantly different from those of hibernating bears. The decrease due to denervation in summer-active bears was comparable to that occurring in other mammals. Whole-muscle cross-sectional areas (CSAs) measured from ultrasound images and myofiber CSAs measured from biopsies decreased similarly to musculotendon mass. Thus, hibernating bears alter skeletal muscle catabolic pathways regulated by neural activity, and exploration of these pathways may offer potential solutions for disuse atrophy of muscles.
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Affiliation(s)
- David C. Lin
- Voiland School of Chemical Engineering and Bioengineering, Washington State University, Pullman, WA 99164, USA
- Department of Veterinary and Comparative Anatomy, Pharmacology and Physiology, Washington State University, Pullman, WA 99164, USA
| | - John D. Hershey
- Department of Veterinary and Comparative Anatomy, Pharmacology and Physiology, Washington State University, Pullman, WA 99164, USA
| | - John S. Mattoon
- Department of Veterinary Clinical Sciences, Washington State University, Pullman, WA 99164, USA
| | - Charles T. Robbins
- Department of Natural Resource Sciences, Washington State University, Pullman, WA 99164, USA
- School of Biological Sciences, Washington State University, Pullman, WA 99164, USA
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65
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Guzun R, Aguilaniu B, Wuyam B, Mezin P, Koechlin-Ramonatxo C, Auffray C, Saks V, Pison C. Effects of training at mild exercise intensities on quadriceps muscle energy metabolism in patients with chronic obstructive pulmonary disease. Acta Physiol (Oxf) 2012; 205:236-46. [PMID: 22118364 DOI: 10.1111/j.1748-1716.2011.02388.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
AIM To study the effects of physical training at mild intensities on skeletal muscle energy metabolism in eight patients with chronic obstructive pulmonary disease (COPD) and eight paired healthy sedentary subjects. METHODS Energy metabolism of patients and controls vastus lateralis muscle was studied before and after 3 months of cycling training at mild exercises intensities. RESULTS The total amount of work accomplished was about 4059 ± 336 kJ in patients with COPD and 7531 ± 1693 kJ in control subjects. This work corresponds to a mechanical power set at 65.2 ± 7.5% of the maximum power for patients with COPD and 52 ± 3.3% of the maximum power in control group. Despite this low level of exercise intensities, we observed an improvement in mitochondrial oxidative phosphorylation through the creatine kinase system revealed by the increased apparent K(m) for ADP (from 105.5 ± 16.1 to 176.9 ± 26.5 μm, P < 0.05 in the COPD group and from 126.9 ± 16.8 to 177.7 ± 17.0, P > 0.05 in the control group). Meanwhile, maximal mechanical and metabolic power increased significantly from 83.1 ± 7.1 to 91.3 ± 7.4 Watts (P < 0.05) and from 16 ± 0.8 to 18.7 ± 0.98 mL O(2) kg(-1) min(-1) (P < 0.05) only in the COPD group. CONCLUSION This study shows that physical training at mild intensity is able to induce comparable changes in skeletal muscles oxidative energy metabolism in patients with COPD and sedentary healthy subjects, but different changes of maximal mechanical and metabolic power.
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Affiliation(s)
- R Guzun
- Laboratory of Fundamental and Applied Bioenergetics, Joseph Fourier University, Grenoble, France.
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66
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Bogdanis GC. Effects of physical activity and inactivity on muscle fatigue. Front Physiol 2012; 3:142. [PMID: 22629249 PMCID: PMC3355468 DOI: 10.3389/fphys.2012.00142] [Citation(s) in RCA: 158] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2012] [Accepted: 04/27/2012] [Indexed: 12/22/2022] Open
Abstract
The aim of this review was to examine the mechanisms by which physical activity and inactivity modify muscle fatigue. It is well known that acute or chronic increases in physical activity result in structural, metabolic, hormonal, neural, and molecular adaptations that increase the level of force or power that can be sustained by a muscle. These adaptations depend on the type, intensity, and volume of the exercise stimulus, but recent studies have highlighted the role of high intensity, short-duration exercise as a time-efficient method to achieve both anaerobic and aerobic/endurance type adaptations. The factors that determine the fatigue profile of a muscle during intense exercise include muscle fiber composition, neuromuscular characteristics, high energy metabolite stores, buffering capacity, ionic regulation, capillarization, and mitochondrial density. Muscle fiber-type transformation during exercise training is usually toward the intermediate type IIA at the expense of both type I and IIx myosin heavy-chain isoforms. High-intensity training results in increases of both glycolytic and oxidative enzymes, muscle capillarization, improved phosphocreatine resynthesis and regulation of K+, H+, and lactate ions. Decreases of the habitual activity level due to injury or sedentary lifestyle result in partial or even compete reversal of the adaptations due to previous training, manifested by reductions in fiber cross-sectional area, decreased oxidative capacity, and capillarization. Complete immobilization due to injury results in markedly decreased force output and fatigue resistance. Muscle unloading reduces electromyographic activity and causes muscle atrophy and significant decreases in capillarization and oxidative enzymes activity. The last part of the review discusses the beneficial effects of intermittent high-intensity exercise training in patients with different health conditions to demonstrate the powerful effect of exercise on health and well being.
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Affiliation(s)
- Gregory C Bogdanis
- Department of Physical Education and Sports Science, University of Athens Athens, Greece
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Kohn TA, Curry JW, Noakes TD. Black wildebeest skeletal muscle exhibits high oxidative capacity and a high proportion of type IIx fibres. ACTA ACUST UNITED AC 2012; 214:4041-7. [PMID: 22071196 DOI: 10.1242/jeb.061572] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The aim of the study was to investigate the skeletal muscle characteristics of black wildebeest (Connochaetes gnou) in terms of fibre type and metabolism. Samples were obtained post mortem from the vastus lateralis and longissimus lumborum muscles and analysed for myosin heavy chain (MHC) content. Citrate synthase (CS), 3-hydroxyacyl co A dehydrogenase (3HAD), phosphofructokinase (PFK), lactate dehydrogenase (LDH) and creatine kinase (CK) activities were measured spectrophotometrically to represent the major metabolic pathways in these muscles. Both muscles had less than 20% MHC I, whereas MHC IIa and MHC IIx were expressed in excess of 50% in the vastus lateralis and longissimus lumborum muscles, respectively. Overall fibre size was 2675±1034 μm(2), which is small compared with other species. Oxidative capacity (CS and 3HAD) in both muscles was high and did not differ from one another, but the longissimus lumborum had significantly (P<0.05) higher PFK, LDH and CK activities. No relationships were observed between fibre type and the oxidative and oxygen-independent metabolic capacity as measured by specific enzyme activities. This study confirms the presence of both fast-twitch fibres and high oxidative capacity in black wildebeest, indicating an animal that can run very fast but is also fatigue resistant.
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Affiliation(s)
- Tertius Abraham Kohn
- UCT/MRC Research Unit for Exercise Science and Sports Medicine, Department of Human Biology, University of Cape Town, Newlands, South Africa.
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68
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Age-Related Changes in Myosin Light and Heavy Chain Isoforms’ Composition in Gluteus Medius Muscle of Sedentary Akhal-Teke Horses. J Equine Vet Sci 2011. [DOI: 10.1016/j.jevs.2011.03.006] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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69
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Montowska M, Pospiech E. Differences in two-dimensional gel electrophoresis patterns of skeletal muscle myosin light chain isoforms between Bos taurus, Sus scrofa and selected poultry species. JOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE 2011; 91:2449-2456. [PMID: 21656778 DOI: 10.1002/jsfa.4486] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2010] [Revised: 03/17/2011] [Accepted: 04/19/2011] [Indexed: 05/30/2023]
Abstract
BACKGROUND In this study the interspecies differences in two-dimensional electrophoresis patterns of skeletal muscle myosin light chain (MLC) isoforms between Bos taurus (cattle), Sus scrofa (pig), Gallus gallus (chicken), Meleagris gallopavo (turkey), Anas platyrhynchos (duck) and Anser anser (goose) were characterised on the basis of specific properties of MLCs associated with their structure and mobility in gel. RESULTS Two-dimensional electrophoresis separations revealed species-specific differences in the molecular weight and pI of individual MLC isoforms (MLC1f, MLC2f and MLC3f). In the case of closely related animal species such as goose and duck or turkey and chicken, significant differences occurred in MLC1f. For MLC2f, differences between cattle and turkey and between pig and chicken were around 1 and 0.3 kDa respectively. It appeared from the comparison of amino acid sequences that even MLCs with only 2% difference in sequences have different electrophoretic mobilities. CONCLUSION Interspecies differences in skeletal MLC isoforms appeared between cattle, pig, chicken, turkey, duck and goose. The slight changes observed in the course of the aging process confirmed that these proteins are relatively little susceptible to proteolytic enzymes during meat aging.
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Affiliation(s)
- Magdalena Montowska
- Institute of Meat Technology, Poznań University of Life Sciences, Poznań, Poland.
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Neunhäuserer D, Zebedin M, Obermoser M, Moser G, Tauber M, Niebauer J, Resch H, Galler S. Human skeletal muscle: transition between fast and slow fibre types. Pflugers Arch 2011; 461:537-43. [PMID: 21360037 DOI: 10.1007/s00424-011-0943-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2011] [Revised: 02/15/2011] [Accepted: 02/17/2011] [Indexed: 10/18/2022]
Abstract
Human skeletal muscles consist of different fibre types: slow fibres (slow twitch or type I) containing the myosin heavy chain isoform (MHC)-I and fast fibres (fast twitch or type II) containing MHC-IIa (type IIA) or MHC-IId (type IID). The following order of decreasing kinetics is known: type IID > type IIA >> type I. This order is especially based on the kinetics of stretch activation, which is the most discriminative property among fibre types. In this study we tested if hybrid fibres containing both MHC-IIa and MHC-I (type C fibres) provide a transition in kinetics between fast (type IIA) and slow fibres (type I). Our data of stretch activation kinetics suggest that type C fibres, with different ratios of MHC-IIa and MHC-I, do not provide a continuous transition. Instead, a specialized group of slow fibres, which we called "transition fibres", seems to provide a transition. Apart of their kinetics of stretch activation, which is most close to that of type IIA, the transition fibres are characterized by large cross-sectional areas and low maximal tensions. The molecular cause for the mechanical properties of the transition fibres is unknown. It is possible that the transition fibres contain an unknown slow MHC isoform, which cannot be separated by biochemical methods. Alternatively, or in addition, isoforms of myofibrillar proteins, other than MHC, and posttranslational modifications of myofibrillar proteins could play a role regarding the characteristics of the transition fibres.
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Affiliation(s)
- Daniel Neunhäuserer
- Department of Sports Medicine, Prevention and Rehabilitation, Paracelsus Medical University Salzburg, Lindhofstr. 20, 5020, Salzburg, Austria.
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71
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Kohn TA, Burroughs R, Hartman MJ, Noakes TD. Fiber type and metabolic characteristics of lion (Panthera leo), caracal (Caracal caracal) and human skeletal muscle. Comp Biochem Physiol A Mol Integr Physiol 2011; 159:125-33. [PMID: 21320626 DOI: 10.1016/j.cbpa.2011.02.006] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2010] [Revised: 02/02/2011] [Accepted: 02/05/2011] [Indexed: 11/19/2022]
Abstract
Lion (Panthera leo) and caracal (Caracal caracal) skeletal muscle samples from Vastus lateralis, Longissimus dorsi and Gluteus medius were analyzed for fiber type and citrate synthase (CS; EC 2.3.3.1), 3-hydroxyacyl Co A dehydrogenase (3HAD; EC 1.1.1.35), phosphofructokinase-1 (PFK; EC 2.7.1.11), creatine kinase (CK; EC 2.7.3.2), phosphorylase (PHOS; EC 2.4.1.1) and lactate dehydrogenase (LDH; EC 1.1.1.27) activities and compared to human runners, the latter also serving as validation of methodology. Both felids had predominantly type IIx fibers (range 50-80%), whereas human muscle had more types I and IIa. Oxidative capacity of both felids (CS: 5-9 μmol/min/g ww and 3HAD: 1.4-2.6 μmol/min/g ww) was lower than humans, whereas the glycolytic capacity was elevated. LDH activity of caracal (346 ± 81) was higher than lion (227 ± 62 μmol/min/g ww), with human being the lowest (55 ± 17). CK and PHOS activities were also higher in caracal and lion compared to human, but PFK was lower in both felid species. The current data and past research are illustrated graphically showing a strong relationship between type II fibers and sprinting ability in various species. These data on caracal and lion muscles confirm their sprinting behavior.
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Affiliation(s)
- Tertius Abraham Kohn
- UCT/MRC Research Unit for Exercise Science and Sports Medicine, Department of Human Biology, PO Box 115, Newlands 7725, South Africa.
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Purcell TJ, Naber N, Franks-Skiba K, Dunn AR, Eldred CC, Berger CL, Málnási-Csizmadia A, Spudich JA, Swank DM, Pate E, Cooke R. Nucleotide pocket thermodynamics measured by EPR reveal how energy partitioning relates myosin speed to efficiency. J Mol Biol 2010; 407:79-91. [PMID: 21185304 DOI: 10.1016/j.jmb.2010.11.053] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2010] [Revised: 11/24/2010] [Accepted: 11/26/2010] [Indexed: 11/26/2022]
Abstract
We have used spin-labeled ADP to investigate the dynamics of the nucleotide-binding pocket in a series of myosins, which have a range of velocities. Electron paramagnetic resonance spectroscopy reveals that the pocket is in equilibrium between open and closed conformations. In the absence of actin, the closed conformation is favored. When myosin binds actin, the open conformation becomes more favored, facilitating nucleotide release. We found that faster myosins favor a more closed pocket in the actomyosin•ADP state, with smaller values of ΔH(0) and ΔS(0), even though these myosins release ADP at a faster rate. A model involving a partitioning of free energy between work-generating steps prior to rate-limiting ADP release explains both the unexpected correlation between velocity and opening of the pocket and the observation that fast myosins are less efficient than slow myosins.
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Affiliation(s)
- Thomas J Purcell
- Department of Biochemistry and Biophysics, UCSF MC 2240, Genentech Hall Room S416C, 600 16th Street, San Francisco, CA 94158-2517, USA.
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73
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Li M, Larsson L. Force-generating capacity of human myosin isoforms extracted from single muscle fibre segments. J Physiol 2010; 588:5105-14. [PMID: 20974679 DOI: 10.1113/jphysiol.2010.199067] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
Muscle, motor unit and muscle fibre type-specific differences in force-generating capacity have been investigated for many years, but there is still no consensus regarding specific differences between slow- and fast-twitch muscles, motor units or muscle fibres. This is probably related to a number of different confounding factors disguising the function of the molecular motor protein myosin. We have therefore studied the force-generating capacity of specific myosin isoforms or combination of isoforms extracted from short single human muscle fibre segments in a modified single fibre myosin in vitro motility assay, in which an internal load (actin-binding protein) was added in different concentrations to evaluate the force-generating capacity. The force indices were the x-axis intercept and the slope of the relationship between the fraction of moving filaments and the α-actinin concentration. The force-generating capacity of the β/slow myosin isoform (type I) was weaker (P < 0.05) than the fast myosin isoform (type II), but the force-generating capacity of the different human fast myosin isoforms types IIa and IIx or a combination of both (IIax) were indistinguishable. A single fibre in vitro motility assay for both speed and force of specific myosin isoforms is described and used to measure the difference in force-generating capacity between fast and slow human myosin isoforms. The assay is proposed as a useful tool for clinical studies on the effects on muscle function of specific mutations or post-translational modifications of myosin.
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Affiliation(s)
- Meishan Li
- Department of Clinical Neurophysiology, Uppsala University Hospital, SE-751 85 Uppsala, Sweden
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Sasaki K, Ishii N. Unloaded shortening velocity of voluntarily and electrically activated human dorsiflexor muscles in vivo. PLoS One 2010; 5:e13043. [PMID: 20885951 PMCID: PMC2946376 DOI: 10.1371/journal.pone.0013043] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2010] [Accepted: 09/03/2010] [Indexed: 11/25/2022] Open
Abstract
We have previously shown that unloaded shortening velocity (V(0)) of human plantar flexors can be determined in vivo, by applying the "slack test" to submaximal voluntary contractions (J Physiol 567:1047-1056, 2005). In the present study, to investigate the effect of motor unit recruitment pattern on V(0) of human muscle, we modified the slack test and applied this method to both voluntary and electrically elicited contractions of dorsiflexors. A series of quick releases (i.e., rapid ankle joint rotation driven by an electrical dynamometer) was applied to voluntarily activated dorsiflexor muscles at three different contraction intensities (15, 50, and 85% of maximal voluntary contraction; MVC). The quick-release trials were also performed on electrically activated dorsiflexor muscles, in which three stimulus conditions were used: submaximal (equal to 15%MVC) 50-Hz stimulation, supramaximal 50-Hz stimulation, and supramaximal 20-Hz stimulation. Modification of the slack test in vivo resulted in good reproducibility of V(0), with an intraclass correlation coefficient of 0.87 (95% confidence interval: 0.68-0.95). Regression analysis showed that V(0) of voluntarily activated dorsiflexor muscles significantly increased with increasing contraction intensity (R(2) = 0.52, P<0.001). By contrast, V(0) of electrically activated dorsiflexor muscles remained unchanged (R(2)<0.001, P = 0.98) among three different stimulus conditions showing a large variation of tetanic torque. These results suggest that the recruitment pattern of motor units, which is quite different between voluntary and electrically elicited contractions, plays an important role in determining shortening velocity of human skeletal muscle in vivo.
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Affiliation(s)
- Kazushige Sasaki
- Department of Life Sciences, Graduate School of Arts and Sciences, University of Tokyo, Tokyo, Japan.
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75
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GOLDING-MYERS J, SHOWERS C, SHAND P, ROSSER B. MUSCLE FIBER TYPE AND THE OCCURRENCE OF PALE, SOFT, EXUDATIVE PORK. ACTA ACUST UNITED AC 2010. [DOI: 10.1111/j.1745-4573.2009.00197.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Lee SH, Joo ST, Ryu YC. Skeletal muscle fiber type and myofibrillar proteins in relation to meat quality. Meat Sci 2010; 86:166-70. [PMID: 20605337 DOI: 10.1016/j.meatsci.2010.04.040] [Citation(s) in RCA: 163] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2010] [Revised: 04/26/2010] [Accepted: 04/29/2010] [Indexed: 11/19/2022]
Abstract
Although numerous studies have reported the relationships among muscle fiber characteristics, lean meat content and meat quality, controversial perspectives still remain. Conventional histochemical classifications may be involved in a high level of error, subjectivity and it could not clearly explain variety of myofibrillar protein isoforms. Therefore, more information is needed on how different factors, such as species, breeds, gender, nutrient conditions, physiological state of animals, and environment factors, affect ultimate meat quality in order to evaluate these uncertainness. Unfortunately, there is little information that completely covers with relationship among the muscle fiber types, myofibrillar proteins and enzymatic proteolysis. In addition to the perspective of postmortem metabolism, protein quality control in skeletal muscle and proteolytic degradation of muscle proteins during postmortem period could help to clarify this relationship. Therefore, the present review will focus on muscle fiber types, typing methods, muscle proteins and meat quality, and will summarize aspects of enzymatic view of proteasome.
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Affiliation(s)
- S H Lee
- College of Life Sciences and Biotechnology, Korea University, Sungbuk-gu, Seoul, South Korea
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77
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Ferretti G, Bringard A, Perini R. An analysis of performance in human locomotion. Eur J Appl Physiol 2010; 111:391-401. [PMID: 20437056 DOI: 10.1007/s00421-010-1482-y] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/09/2010] [Indexed: 10/19/2022]
Abstract
This paper reports an analysis of the principles underlying human performances on the basis of the work initiated by Pietro Enrico di Prampero. Starting from the concept that the maximal speed that can be attained over a given distance with a given locomotion mode is directly proportional to the maximal sustainable power and inversely proportional to the energy cost of locomotion, we discuss the maximal powers (and capacities) of anaerobic (lactic and alactic) and aerobic metabolisms and the factors that limit them, and the factors affecting the energy cost of various locomotion modes. Special attention is given to the role of air resistance and frictional forces. Finally, computation of performance speed is discussed along the approach originally developed by di Prampero.
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Affiliation(s)
- Guido Ferretti
- Département des Neurosciences Fondamentales, Centre Médical Universitaire, Université de Genève, Rue Michel Servet 1, 1211, Geneve 4, Switzerland.
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Canepari M, Pellegrino MA, D'Antona G, Bottinelli R. Single muscle fiber properties in aging and disuse. Scand J Med Sci Sports 2010; 20:10-9. [DOI: 10.1111/j.1600-0838.2009.00965.x] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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79
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Choi Y, Lee S, Choe J, Rhee M, Lee S, Joo S, Kim B. Protein solubility is related to myosin isoforms, muscle fiber types, meat quality traits, and postmortem protein changes in porcine longissimus dorsi muscle. Livest Sci 2010. [DOI: 10.1016/j.livsci.2009.09.009] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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80
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Calderón JC, Bolaños P, Caputo C. Myosin heavy chain isoform composition and Ca(2+) transients in fibres from enzymatically dissociated murine soleus and extensor digitorum longus muscles. J Physiol 2010; 588:267-79. [PMID: 19884322 PMCID: PMC2821564 DOI: 10.1113/jphysiol.2009.180893] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2009] [Accepted: 10/30/2009] [Indexed: 11/08/2022] Open
Abstract
Electrically elicited Ca(2+) transients reported with the fast Ca(2+) dye MagFluo-4 AM and myosin heavy chain (MHC) electrophoretic patterns were obtained in intact, enzymatically dissociated fibres from adult mice extensor digitorum longus (EDL) and soleus muscles. Thirty nine fibres (23 from soleus and 16 from EDL) were analysed by both fluorescence microscopy and electrophoresis. These fibres were grouped as follows: group 1 included 13 type I and 4 type IC fibres; group 2 included 2 type IIC, 3 IIA and 1 I/IIA/IIX fibres; group 3 included 4 type IIX and 1 type IIX/IIB fibres; group 4 included 2 type IIB/IIX and 9 type IIB fibres. Ca(2+) transients obtained in groups 1, 2, 3 and 4 had the following kinetic parameters (mean +/- s.e.m.): amplitude (F/F): 0.61 +/- 0.05, 0.53 +/- 0.08, 0.61 +/- 0.06 and 0.61 +/- 0.03; rise time (ms): 1.64 +/- 0.05, 1.35 +/- 0.05, 1.18 +/- 0.06 and 1.14 +/- 0.04; half-amplitude width (ms): 19.12 +/- 1.85, 11.86 +/- 3.03, 4.62 +/- 0.31 and 4.23 +/- 0.37; and time constants of decay (tau(1) and tau(2), ms): 3.33 +/- 0.13 and 52.48 +/- 3.93, 2.69 +/- 0.22 and 41.06 +/- 9.13, 1.74 +/- 0.06 and 12.88 +/- 1.93, and 1.56 +/- 0.11 and 9.45 +/- 1.03, respectively. The statistical differences between the four groups and the analysis of the distribution of the parameters of Ca(2+) release and clearance show that there is a continuum from slow to fast, that parallels the MHC continuum from pure type I to pure IIB. However, type IIA fibres behave more like IIX and IIB fibres regarding Ca(2+) release but closer to type I fibres regarding Ca(2+) clearance. In conclusion, we show for the first time the diversity of Ca(2+) transients for the whole continuum of fibre types and correlate this functional diversity with the structural and biochemical diversity of the skeletal muscle fibres.
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Affiliation(s)
- Juan C Calderón
- Laboratory of Cellular Physiology, Centre of Biophysics and Biochemistry, Venezuelan Institute for Scientific Research (IVIC), Caracas 1020A, Venezuela.
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81
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Rahnert JA, Sokoloff AJ, Burkholder TJ. Sarcomeric myosin expression in the tongue body of humans, macaques and rats. Cells Tissues Organs 2009; 191:431-42. [PMID: 19907142 DOI: 10.1159/000258678] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/30/2009] [Indexed: 11/19/2022] Open
Abstract
Expression of developmental and unconventional myosin heavy chain (MHC) isoforms in some adult head and neck muscles is thought to reflect specific contractile demands of muscle fibers active during kinematically complex movements. Mammalian tongue muscles are active during oromotor behaviors that encompass a wide range of tongue movement speeds and tongue shape changes (e.g. respiration, oral transport, swallowing, rejection), but the extent to which tongue muscles express developmental and unconventional MHC is not known. Quantitative PCR was used to determine the mRNA content of conventional MHC-beta, MHC-2a, MHC-2b and MHC-2x, the developmental isoforms embryonic MHC and neonatal MHC and the unconventional isoforms atrial/cardiac-alpha MHC (MHC-alpha), extraocular MHC, masseter MHC and slow tonic MHC in tongue body muscles of the rat, macaque and human. In all species, conventional MHC isoforms predominate. MHC-2b and MHC-2x account for 98% of total MHC mRNA in the rat. MHC-2a, MHC-2x and MHC-beta account for 94% of total MHC mRNA in humans and 96% of total MHC mRNA in macaque. With the exception of MHC-alpha in humans (5%), developmental and unconventional MHC mRNA represents less than 0.3% of total MHC mRNA. We conclude that in these species, there is limited expression of developmental and unconventional MHC and that diversity of tongue body muscle fiber contractile properties is achieved primarily by MHC-beta, MHC-2a, MHC-2x and MHC-2b. Whether expression of MHC-alpha mRNA in tongue is unique to humans or present in other hominoids awaits further investigation.
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Affiliation(s)
- Jill A Rahnert
- School of Applied Physiology, Georgia Institute of Technology, Atlanta, GA, USA
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Miller MS, Vanburen P, Lewinter MM, Lecker SH, Selby DE, Palmer BM, Maughan DW, Ades PA, Toth MJ. Mechanisms underlying skeletal muscle weakness in human heart failure: alterations in single fiber myosin protein content and function. Circ Heart Fail 2009; 2:700-6. [PMID: 19919996 DOI: 10.1161/circheartfailure.109.876433] [Citation(s) in RCA: 65] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
BACKGROUND Patients with chronic heart failure (HF) frequently experience skeletal muscle weakness that limits physical function. The mechanisms underlying muscle weakness, however, have not been clearly defined. METHODS AND RESULTS This study examined the hypothesis that HF promotes a loss of myosin protein from single skeletal muscle fibers, which in turn reduces contractile performance. Ten patients with chronic HF and 10 controls were studied. Muscle atrophy was not evident in patients, and groups displayed similar physical activity levels, suggesting that observed differences reflect the effects of HF and not muscle atrophy or disuse. In single muscle fibers, patients with HF showed reduced myosin heavy chain protein content (P<0.05) that manifested as a reduction in functional myosin-actin cross-bridges (P<0.05). No evidence was found for a generalized loss of myofilament protein, suggesting a selective loss of myosin. Accordingly, single muscle fiber maximal Ca(2+)-activated tension was reduced in myosin heavy chain I fibers in patients (P<0.05). However, tension was maintained in myosin heavy chain IIA fibers in patients because a greater proportion of available myosin heads were bound to actin during Ca(2+) activation (P<0.01). CONCLUSIONS Collectively, our results show that HF alters the quantity and functionality of the myosin molecule in skeletal muscle, leading to reduced tension in myosin heavy chain I fibers. Loss of single fiber myosin protein content represents a potential molecular mechanism underlying muscle weakness and exercise limitation in patients with HF.
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Affiliation(s)
- Mark S Miller
- Departments of Molecular Physiology and Biophysics and Medicine, University of Vermont, College of Medicine, Burlington, Vt, USA
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Zapata I, Zerby HN, Wick M. Functional proteomic analysis predicts beef tenderness and the tenderness differential. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2009; 57:4956-4963. [PMID: 19449808 DOI: 10.1021/jf900041j] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Inconsistent tenderness is one of the most detrimental factors of meat quality. Functional proteomics was used to associate electrophoretic bands from the myofibrillar muscle fraction to meat tenderness in an effort to gain understanding of the mechanisms controlling tenderness. The myofibrillar muscle fraction of the Longissimus dorsi from 22 Angus cross steers was analyzed by SDS-PAGE and linearly regressed to Warner-Bratzler shear values. Six significant electrophoretic bands were characterized by electrophoretic and statistical analysis and sequenced by nano-LC-MS/MS. The protein(s)/peptide(s) identified in these bands encompass a wide array of cellular pathways related to structural, metabolic, chaperone, and developmental functions. This study begins to assemble information that has been reported separately into a more complete picture that will lead to the establishment of a coherent mechanism accounting for meat tenderness.
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Affiliation(s)
- Isain Zapata
- Department of Animal Sciences, The Ohio State University, Columbus, Ohio 43210, USA
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84
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85
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86
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Insights into the kinetics of Ca2+-regulated contraction and relaxation from myofibril studies. Pflugers Arch 2009; 458:337-57. [PMID: 19165498 DOI: 10.1007/s00424-008-0630-2] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2008] [Accepted: 12/24/2008] [Indexed: 01/06/2023]
Abstract
Muscle contraction results from force-generating interactions between myosin cross-bridges on the thick filament and actin on the thin filament. The force-generating interactions are regulated by Ca(2+) via specialised proteins of the thin filament. It is controversial how the contractile and regulatory systems dynamically interact to determine the time course of muscle contraction and relaxation. Whereas kinetics of Ca(2+)-induced thin-filament regulation is often investigated with isolated proteins, force kinetics is usually studied in muscle fibres. The gap between studies on isolated proteins and structured fibres is now bridged by recent techniques that analyse the chemical and mechanical kinetics of small components of a muscle fibre, subcellular myofibrils isolated from skeletal and cardiac muscle. Formed of serially arranged repeating units called sarcomeres, myofibrils have a complete fully structured ensemble of contractile and Ca(2+) regulatory proteins. The small diameter of myofibrils (few micrometres) facilitates analysis of the kinetics of sarcomere contraction and relaxation induced by rapid changes of [ATP] or [Ca(2+)]. Among the processes studied on myofibrils are: (1) the Ca(2+)-regulated switch on/off of the troponin complex, (2) the chemical steps in the cross-bridge adenosine triphosphatase cycle, (3) the mechanics of force generation and (4) the length dynamics of individual sarcomeres. These studies give new insights into the kinetics of thin-filament regulation and of cross-bridge turnover, how cross-bridges transform chemical energy into mechanical work, and suggest that the cross-bridge ensembles of each half-sarcomere cooperate with each other across the half-sarcomere borders. Additionally, we now have a better understanding of muscle relaxation and its impairment in certain muscle diseases.
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87
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Sa HS, Oh SY. The Changes in Myosin Heavy Chain Isoforms After Extraocular Muscle Recession in Rabbits. JOURNAL OF THE KOREAN OPHTHALMOLOGICAL SOCIETY 2009. [DOI: 10.3341/jkos.2009.50.8.1259] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Affiliation(s)
- Ho-Seok Sa
- Department of Ophthalmology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea
| | - Sei Yeul Oh
- Department of Ophthalmology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea
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88
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Changes in muscle fiber size and in the composition of myosin heavy chain isoforms of rabbit extraocular rectus muscle following recession surgery. Jpn J Ophthalmol 2008; 52:386-392. [PMID: 18991040 DOI: 10.1007/s10384-008-0568-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2007] [Accepted: 06/01/2008] [Indexed: 10/21/2022]
Abstract
PURPOSE To assess the changes in the size of muscle fibers and the composition of myosin heavy chain (MyHC) isoforms in the global layer (GL) and the orbital layer (OL) of rabbit rectus extraocular muscle (EOM) after recession. METHODS The right superior rectus muscles of two rabbits were harvested at 3 days or 1, 2, or 4 weeks after recession (eight rabbits in total). At each time point, one muscle was used for measuring the cross-sectional area of the muscle fibers and the other for identifying the composition of MyHC. The right superior rectus muscles of three additional naïve rabbits were used as controls. RESULTS The mean cross-sectional area of the OL fibers did not change significantly. However, that of the GL fibers significantly decreased at 3 days (P<0.001) and 1 week (P=0.024) postoperatively, and increased thereafter to reach the control levels at 2 and 4 weeks postoperatively. Three days after surgery, the total MyHC content and the proportion of type IIb MyHC (MyHCIIb) plus EOM-specific MyHC (MyHCeom) decreased and remained at its lower level for 4 weeks. CONCLUSIONS Transient atrophy and regeneration were observed only in the GL, and the changes in the MyHCIIb plus MyHCeom appeared to be related to these changes.
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89
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Luden N, Minchev K, Hayes E, Louis E, Trappe T, Trappe S. Human vastus lateralis and soleus muscles display divergent cellular contractile properties. Am J Physiol Regul Integr Comp Physiol 2008; 295:R1593-8. [PMID: 18815206 PMCID: PMC2584861 DOI: 10.1152/ajpregu.90564.2008] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2008] [Accepted: 09/18/2008] [Indexed: 11/22/2022]
Abstract
The purpose of this study was to investigate potential differences in single-fiber contractile physiology of fibers with the same myosin heavy chain isoform (MHC I and MHC IIa) originating from different muscles. Vastus lateralis (VL) and soleus biopsies were obtained from 27 recreationally active females (31 +/- 1 yr, 59 +/- 1 kg). A total of 943 single fibers (MHC I = 562; MHC IIa = 301) were isolated and examined for diameter, peak tension (Po), shortening velocity (Vo), and power. The soleus had larger (P < 0.05) fibers (MHC I +18%; MHC IIa +19%), higher MHC I Vo (+13%), and higher MHC I Po (+18%) compared with fibers from the VL. In contrast, fibers from the VL had higher (P < 0.05) specific tension (MHC I +18%; MHC IIa +20%), and MHC I normalized power (+25%) compared with the soleus. There was a trend for MHC IIa soleus fibers to have higher Vo [MHC IIa +13% (P = 0.058)], whereas VL MHC IIa fibers showed a trend for higher normalized power compared with soleus fibers [MHC IIa +33% (P = 0.079)]. No differences in absolute power were detected between muscles. These data highlight muscle-specific differences in single-fiber contractile function that should serve as a scientific basis for consideration when extending observations of skeletal muscle tissue from one muscle of interest to other muscles of origin. This is important when examining skeletal muscle adaptation to physical states such as aging, unloading, and training.
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Affiliation(s)
- Nicholas Luden
- Human Performance Laboratory, Ball State Univ., Muncie, Indiana, USA
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90
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Pansarasa O, Rinaldi C, Parente V, Miotti D, Capodaglio P, Bottinelli R. Resistance training of long duration modulates force and unloaded shortening velocity of single muscle fibres of young women. J Electromyogr Kinesiol 2008; 19:e290-300. [PMID: 18801662 DOI: 10.1016/j.jelekin.2008.07.007] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2008] [Revised: 07/20/2008] [Accepted: 07/21/2008] [Indexed: 11/16/2022] Open
Abstract
The aim of the present study was to clarify the impact of long term (1 year) resistance training (RT) on structure and function of single muscle fibres of vastus lateralis in young female subjects. Five young women (age: 25.4+/-6.2 year) performed exercise sessions at 60% of single subject own repetition maximum (1 RM) 1h twice a week. Maximum voluntary force was determined pre- and post-RT and was found to significantly increase post-RT ensuring a successful impact of RT on muscle performance in vivo. Needle muscle biopsy samples were obtained both pre- and post-RT and the following determinations were performed: myosin heavy chain isoform (MHC) distribution of the whole muscle samples by SDS-PAGE; cross sectional area (CSA), specific force (Po/CSA) and maximum shortening velocity (Vo) of a large population (n=358) of single skinned muscle fibres classified on the basis of MHC isoform composition by SDS-PAGE. The results suggest that the long duration of RT can determine a significant increase in specific force (Po/CSA) and unloaded shortening velocity (Vo) of single muscle fibres in female subjects, whereas no muscle fibre hypertrophy and no shift in MHC isoform content was observed.
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Affiliation(s)
- Orietta Pansarasa
- Department of Experimental Medicine, Human Physiology Unit, and Interuniversity Institute of Miology, University of Pavia, Via Forlanini 6, 27100 Pavia, Italy
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91
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Long-term resistance training improves force and unloaded shortening velocity of single muscle fibres of elderly women. Eur J Appl Physiol 2008; 104:885-93. [DOI: 10.1007/s00421-008-0845-0] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/23/2008] [Indexed: 11/25/2022]
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92
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Adaptation of Equine Locomotor Muscle Fiber Types to Endurance and Intensive High Speed Training. J Equine Vet Sci 2008. [DOI: 10.1016/j.jevs.2008.05.007] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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93
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Elworthy S, Hargrave M, Knight R, Mebus K, Ingham PW. Expression of multiple slow myosin heavy chain genes reveals a diversity of zebrafish slow twitch muscle fibres with differing requirements for Hedgehog and Prdm1 activity. Development 2008; 135:2115-26. [PMID: 18480160 DOI: 10.1242/dev.015719] [Citation(s) in RCA: 117] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The zebrafish embryo develops a series of anatomically distinct slow twitch muscle fibres that characteristically express genes encoding lineage-specific isoforms of sarcomeric proteins such as MyHC and troponin. We show here that different subsets of these slow fibres express distinct members of a tandem array of slow MyHC genes. The first slow twitch muscle fibres to differentiate, which are specified by the activity of the transcription factor Prdm1 (also called Ubo or Blimp1) in response to Hedgehog (Hh) signalling, express the smyhc1 gene. Subsequently, secondary slow twitch fibres differentiate in most cases independently of Hh activity. We find that although some of these later-forming fibres also express smyhc1, others express smyhc2 or smyhc3. We show that the smyhc1-positive fibres express the ubo (prdm1) gene and adopt fast twitch fibre characteristics in the absence of Prdm1 activity, whereas those that do not express smyhc1 can differentiate independently of Prdm1 function. Conversely, some smyhc2-expressing fibres, although independent of Prdm1 function, require Hh activity to form. The adult trunk slow fibres express smyhc2 and smyhc3, but lack smyhc1 expression. The different slow fibres in the craniofacial muscles variously express smyhc1, smyhc2 and smyhc3, and all differentiate independently of Prdm1.
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Affiliation(s)
- Stone Elworthy
- MRC Centre for Developmental and Biomedical Genetics and Department of Biomedical Science, University of Sheffield, Western Bank, Sheffield S10 2TN, UK
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94
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Gokhin DS, Ward SR, Bremner SN, Lieber RL. Quantitative analysis of neonatal skeletal muscle functional improvement in the mouse. J Exp Biol 2008; 211:837-43. [DOI: 10.1242/jeb.014340] [Citation(s) in RCA: 86] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
SUMMARY
Postnatal skeletal muscle growth is classically attributed to fiber hypertrophy and myogenic differentiation, but these processes do not account for the size-independent increase of muscle mechanical performance that occurs during postnatal growth. There is also little knowledge about the precise time-course of contractile function or the underlying factors that affect it. The present study investigated morphological factors (muscle fiber size and myofibrillar packing), biochemical factors (myosin heavy chain isoform and desmin intermediate filament protein expression), and muscle architecture during postnatal development in mice. Physiological testing of the mouse tibialis anterior revealed that maximum isometric stress increased from 27±3 kPa at postnatal day 1 to 169±10 kPa by postnatal day 28,roughly a sixfold increase. Morphological measurements revealed a robust increase in the size-independent packing of myofibrillar matrix material occurring with the functional improvement, with just 48.1±5.5% of the cross-sectional area filled with myofibrils at postnatal day 1 whereas 92.5±0.9% was filled by day 28. Expression of four myosin heavy chain isoforms (embryonic, neonatal, IIX and IIB), as well as desmin, correlated significantly with muscle mechanical function. Stepwise multiple regression showed that, of the variables measured, percentage content of neonatal myosin heavy chain was the best predictor of mechanical function during the postnatal time-course. These data provide the first specific structural basis for increases in muscle tension development during growth. Therefore, models of muscle growth must be modified to include an intrinsic quality enhancement component.
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Affiliation(s)
- David S. Gokhin
- Department of Bioengineering, University of California-San Diego and Veterans Affairs Medical Center, La Jolla, CA 92093, USA
- Department of Orthopaedic Surgery, University of California-San Diego and Veterans Affairs Medical Center, La Jolla, CA 92093, USA
| | - Samuel R. Ward
- Department of Radiology, University of California-San Diego and Veterans Affairs Medical Center, La Jolla, CA 92093, USA
| | - Shannon N. Bremner
- Department of Bioengineering, University of California-San Diego and Veterans Affairs Medical Center, La Jolla, CA 92093, USA
- Department of Orthopaedic Surgery, University of California-San Diego and Veterans Affairs Medical Center, La Jolla, CA 92093, USA
| | - Richard L. Lieber
- Department of Bioengineering, University of California-San Diego and Veterans Affairs Medical Center, La Jolla, CA 92093, USA
- Department of Orthopaedic Surgery, University of California-San Diego and Veterans Affairs Medical Center, La Jolla, CA 92093, USA
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95
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Cross-bridge kinetics of fast and slow fibres of cat jaw and limb muscles: correlations with myosin subunit composition. J Muscle Res Cell Motil 2008; 28:329-41. [PMID: 18320334 DOI: 10.1007/s10974-008-9129-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2007] [Accepted: 02/13/2008] [Indexed: 10/22/2022]
Abstract
Mechanical properties of the jaw-closing muscles of the cat are poorly understood. These muscles are known to differ in myosin and fibre type compositions from limb muscles. This work aims to correlate mechanical properties of single fibres in cat jaw and limb muscles with their myosin subunit compositions. The stiffness minimum frequency, f(min), which reflects isometric cross-bridge kinetics, was measured in Ca(2+)-activated glycerinated fast and slow fibres from cat jaw and limb muscles for temperatures ranging between 15 and 30 degrees C by mechanical perturbation analysis. At 15 degrees C, f(min) was 0.5 Hz for limb-slow fibres, 4-6 Hz for jaw-slow fibres, and 10-13 Hz for limb-fast and jaw-fast fibres. The activation energy for f(min) obtained from the slope of the Arrhenius plot for limb-slow fibres was 30-40% higher than values for the other three types of fibres. SDS-PAGE and western blotting using highly specific antibodies verified that limb-fast fibres contained IIA or IIX myosin heavy chain (MyHC). Jaw-fast fibres expressed masticatory MyHC while both jaw-fast and jaw-slow fibres expressed masticatory myosin light chains (MLCs). The nucleotide sequences of the 3' ends of the slow MyHC cDNAs isolated from cat masseter and soleus cDNA libraries showed identical coding and 3'-untranslated regions, suggesting that jaw-slow and limb-slow fibres express the same slow MyHC gene. We conclude that the isometric cross-bridge cycling kinetics of jaw-fast and limb-fast fibres detected by f(min) are indistinguishable in spite of differences in MyHC and light chain compositions. However, jaw-slow fibres, in which the same slow MyHCs are found in combination with MLCs of the jaw type, show enhanced cross-bridge cycling kinetics and reduced activation energy for cross-bridge detachment.
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96
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Hafer-Macko CE, Ryan AS, Ivey FM, Macko RF. Skeletal muscle changes after hemiparetic stroke and potential beneficial effects of exercise intervention strategies. JOURNAL OF REHABILITATION RESEARCH AND DEVELOPMENT 2008; 45:261-72. [PMID: 18566944 PMCID: PMC2978978 DOI: 10.1682/jrrd.2007.02.0040] [Citation(s) in RCA: 134] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Stroke is the leading cause of disability in the United States. New evidence reveals significant structural and metabolic changes in skeletal muscle after stroke. Muscle alterations include gross atrophy and shift to fast myosin heavy chain in the hemiparetic (contralateral) leg muscle; both are related to gait deficit severity. The underlying molecular mechanisms of this atrophy and muscle phenotype shift are not known. Inflammatory markers are also present in contralateral leg muscle after stroke. Individuals with stroke have a high prevalence of insulin resistance and diabetes. Skeletal muscle is a major site for insulin-glucose metabolism. Increasing evidence suggests that inflammatory pathway activation and oxidative injury could lead to wasting, altered function, and impaired insulin action in skeletal muscle. The health benefits of exercise in disabled populations have now been recognized. Aerobic exercise improves fitness, strength, and ambulatory performance in subjects with chronic stroke. Therapeutic exercise may modify or reverse skeletal muscle abnormalities.
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97
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Abstract
Repeated, intense use of muscles leads to a decline in performance known as muscle fatigue. Many muscle properties change during fatigue including the action potential, extracellular and intracellular ions, and many intracellular metabolites. A range of mechanisms have been identified that contribute to the decline of performance. The traditional explanation, accumulation of intracellular lactate and hydrogen ions causing impaired function of the contractile proteins, is probably of limited importance in mammals. Alternative explanations that will be considered are the effects of ionic changes on the action potential, failure of SR Ca2+release by various mechanisms, and the effects of reactive oxygen species. Many different activities lead to fatigue, and an important challenge is to identify the various mechanisms that contribute under different circumstances. Most of the mechanistic studies of fatigue are on isolated animal tissues, and another major challenge is to use the knowledge generated in these studies to identify the mechanisms of fatigue in intact animals and particularly in human diseases.
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98
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Role of muscle mass on sprint performance: gender differences? Eur J Appl Physiol 2007; 102:685-94. [DOI: 10.1007/s00421-007-0648-8] [Citation(s) in RCA: 82] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/02/2007] [Indexed: 10/22/2022]
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99
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Jaw-opening muscle contracts more economically than jaw-closing muscle in rat. Arch Oral Biol 2007; 53:193-8. [PMID: 18028867 DOI: 10.1016/j.archoralbio.2007.09.004] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2007] [Revised: 09/19/2007] [Accepted: 09/19/2007] [Indexed: 11/22/2022]
Abstract
Mandibular movement is achieved by coordinated actions of the jaw muscles. To understand the assigned functional role (e.g., motor or postural role) of each jaw muscle, we characterised not only their contractile and energy-consumption properties but also their compositions of myosin heavy chain (MHC) isoforms. The Ca(2+)-dependent isometric tension development and ATPase activity were simultaneously measured in chemically skinned fibers harvested from rat jaw-closing (masseter and temporalis) and jaw-opening (digastric) muscles. After the measurements of isometric tension development and ATPase activity, the MHC compositions in each preparation were determined by SDS-gel electrophoresis. The Ca(2+)-sensitivity of isometric tension development and ATPase activity was significantly (P<0.001) higher in the digastric fibers than in the masseter and the temporalis fibers. The tension cost (ATPase activity/tension) was significantly (P<0.0001) lower in the digastric fibers than in the masseter and the temporalis fibers. The MHCs in the digastric fibers consisted of a mixture of slow type I and fast type II isoforms, while mostly fast type II isoforms in the masseter and temporalis fibers. These results suggest that in rat the jaw-opening muscle contracts more efficiently in terms of the energy use (i.e., more efficient ATP consumption for tension generation) than the jaw-closing muscle.
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100
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Andruchov O, Galler S. Influence of fast and slow alkali myosin light chain isoforms on the kinetics of stretch-induced force transients of fast-twitch type IIA fibres of rat. Pflugers Arch 2007; 455:1165-72. [DOI: 10.1007/s00424-007-0369-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2007] [Accepted: 10/04/2007] [Indexed: 11/30/2022]
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