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slow and fast twitch muscle fibers and activity

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https://www.readbyqxmd.com/read/29315934/effect-of-euk-134-on-akt-mtor-signaling-in-the-rat-soleus-during-7-days-of-mechanical-unloading
#1
J Matthew Kuczmarski, Jeff M Hord, Yang Lee, Vinicius Guzzoni, Dinah Rodriguez, Matthew S Lawler, Erika L Garcia-Villatoro, Dylan Holly, Patrick Ryan, Kristian Falcon, Marcela Garcia, Mariana Janini Gomes, James D Fluckey, John M Lawler
Mechanical unloading stimulates rapid changes in skeletal muscle morphology, characterized by atrophy of muscle fiber cross-sectional area (CSA) and a partial fiber-type shift from slow to fast-twitch. Recent studies revealed that oxidative stress contributes to activation of FoxO3a, proteolytic signaling and unloading-induced muscle atrophy via translocation of the mu-splice variant of neuronal nitric oxide synthase (nNOSμ) and activation of FoxO3a. Yet, there is limited understanding of the role of reactive oxygen species (ROS) on the Akt-mTOR pathway signaling during unloading...
January 8, 2018: Experimental Physiology
https://www.readbyqxmd.com/read/29299218/electrical-stimulation-frequency-and-skeletal-muscle-characteristics-effects-on-force-and-fatigue
#2
Maria Vromans, Pouran Faghri
This investigation aimed to determine the force and muscle surface electromyography (EMG) responses to different frequencies of electrical stimulation (ES) in two groups of muscles with different size and fiber composition (fast- and slow-twitch fiber proportions) during a fatigue-inducing protocol. Progression towards fatigue was evaluated in the abductor pollicis brevis (APB) and vastus lateralis (VL) when activated by ES at three frequencies (10, 35, and 50Hz). Ten healthy adults (mean age: 23.2 ± 3.0 years) were recruited; participants signed an IRB approved consent form prior to participation...
December 5, 2017: European Journal of Translational Myology
https://www.readbyqxmd.com/read/29291007/alteration-of-muscle-fiber-characteristics-and-the-ampk-sirt1-pgc-1%C3%AE-axis-in-skeletal-muscle-of-growing-pigs-fed-low-protein-diets-with-varying-branched-chain-amino-acid-ratios
#3
Yehui Duan, Fengna Li, Wenlong Wang, Qiuping Guo, Chaoyue Wen, Yulong Yin
There mainly exists four major myosin heavy chains (MyHC) (i.e., I, IIa, IIx, and IIb) in growing pigs. The current study aimed to explore the effects of low-protein diets supplemented with varying branched-chain amino acids (BCAAs) on muscle fiber characteristics and the AMPK-SIRT1-PGC-1α axis in skeletal muscles. Forty growing pigs (9.85 ± 0.35 kg) were allotted to 5 groups and fed with diets supplemented with varying leucine: isoleucine: valine ratios: 1:0.51:0.63 (20% crude protein, CP), 1:1:1 (17% CP), 1:0...
December 5, 2017: Oncotarget
https://www.readbyqxmd.com/read/29289708/effect-of-ageing-on-the-myosin-heavy-chain-composition-of-the-human-sternocleidomastoid-muscle
#4
M Meznaric, I Eržen, P Karen, E Cvetko
The myosin heavy chain (MyHC) composition of ageing limb muscles is transformed into a slower phenotype and expresses fast-twitch fiber type atrophy, presumably due to age-related motor unit remodeling and a change in the patterns of physical activity. It is not known if ageing affects the sternocleidomastoid muscle (SCM) in a similar way. The goal of the study was to analyze the MyHC composition and the size of muscle fibres in the ageing SCM by immunohistochemical methods and quantitative analysis and stereology using our own software for morphometry...
December 28, 2017: Annals of Anatomy, Anatomischer Anzeiger: Official Organ of the Anatomische Gesellschaft
https://www.readbyqxmd.com/read/29169055/functional-electrical-stimulation-induced-muscular-fatigue-effect-of-fiber-composition-and-stimulation-frequency-on-rate-of-fatigue-development
#5
Maria Vromans, Pouran D Faghri
This investigation evaluated the progression towards fatigue in two muscles of differing fast- and slow-twitch fiber proportions (abductor pollicis brevis (APB) and vastus lateralis (VL)) when activated by functional electrical stimulation (FES) at three frequencies (10, 35, and 50 Hz). Fatigue was defined as a 50% drop from the initial FES-induced force of 25% maximal voluntary contraction (MVC). Ten healthy adults (mean age: 23.2 ± 3.0 years) were recruited; participants signed an IRB approved consent form prior to participation...
November 20, 2017: Journal of Electromyography and Kinesiology
https://www.readbyqxmd.com/read/28983629/expression-of-carbonic-anhydrase-iii-and-skeletal-muscle-remodeling-following-selective-denervation
#6
He Huang, Yanling Zhao, Xiliang Shang, Xueyuan Liu, Huimin Ren
Carbonic anhydrase III (CAIII) is expressed selectively in type I (slow‑twitch) myofibers. To investigate the association between changes in the expression of CAIII and skeletal muscle structure following denervation, the present study stained adjacent sections of skeletal muscle for ATPase and immunohistochemically for CAIII. In addition, differences in the protein expression and phosphatase activity of CAIII were examined by western blot and phosphatase staining between rat soleus and extensol digitorum longus (EDL) muscles, which are composed of predominantly slow‑ and fast‑twitch fibers, respectively...
December 2017: Molecular Medicine Reports
https://www.readbyqxmd.com/read/28977603/androgen-action-via-the-androgen-receptor-in-neurons-within-the-brain-positively-regulates-muscle-mass-in-male-mice
#7
Rachel A Davey, Michele V Clarke, Patricia K Russell, Kesha Rana, Jane Seto, Kelly N Roeszler, Jackie M Y How, Ling Yeong Chia, Kathryn North, Jeffrey D Zajac
Although it is well established that exogenous androgens have anabolic effects on skeletal muscle mass in humans and mice, data from muscle-specific androgen receptor (AR) knockout (ARKO) mice indicate that myocytic expression of the AR is dispensable for hind-limb muscle mass accrual in males. To identify possible indirect actions of androgens via the AR in neurons to regulate muscle, we generated neuron-ARKO mice in which the dominant DNA binding-dependent actions of the AR are deleted in neurons of the cortex, forebrain, hypothalamus, and olfactory bulb...
October 1, 2017: Endocrinology
https://www.readbyqxmd.com/read/28966053/proteome-analysis-in-dystrophic-mdx-mouse-muscle-reveals-a-drastic-alteration-of-key-metabolic-and-contractile-proteins-after-chronic-exercise-and-the-potential-modulation-by-anti-oxidant-compounds
#8
Tania Gamberi, Tania Fiaschi, Elisa Valocchia, Alessandra Modesti, Paola Mantuano, Jean-Francois Rolland, Francesca Sanarica, Annamaria De Luca, Francesca Magherini
Weakness and fatigability are typical features of Duchenne muscular dystrophy patients and are aggravated in dystrophic mdx mice by chronic treadmill exercise. In the present study, we describe, the pattern of differentially abundant spots that is associated to the worsening of dystrophy phenotype induced by chronic exercise. Our proteomic analysis pointed out 34 protein spots with different abundance between sedentary and exercised mdx mice. These proteins belong mostly to glucose metabolism, energy production and sarcomere structure categories...
January 6, 2018: Journal of Proteomics
https://www.readbyqxmd.com/read/28927901/age-related-reductions-in-muscle-quality-influence-the-relative-differences-in-strength-and-power
#9
Gena R Gerstner, Hayden K Giuliani, Jacob A Mota, Eric D Ryan
Age-related changes in the relative differences in isokinetic strength and power may reflect fast twitch fiber function. We aimed to examine the influence of muscle quality on the relative differences in strength and power in younger and older men. Twenty younger (20.1±1.5yrs) and 20 older (69.5±3.1yrs) healthy, recreationally active men performed two plantarflexion maximal voluntary isometric contractions (MVCs) and three maximal concentric isokinetic contractions at a slow (0.52rad·s(-1)) and fast (2.09rad·s(-1)) velocity...
December 1, 2017: Experimental Gerontology
https://www.readbyqxmd.com/read/28767362/modeling-of-stretch-reflex-activation-considering-muscle-type
#10
Moon J Kang, Choongsoo S Shin, Hong H Yoo
Although the stretch reflex plays an important role in spasticity, so far the stretch reflex has not been sufficiently investigated. Previous stretch reflex activation models have some limitations, whereby they are not able to predict outcomes of some stretch reflex cases and do not consider uneven distribution of muscle length and stretch velocity on reflex activation. The purpose of this study was 1) to develop a modified stretch reflex activation model employing a new muscle length threshold and weighting factors for slow-twitch fiber and fast-twitch fiber, and 2) to validate the model using pendulum experiments of the lower and upper limbs...
July 31, 2017: IEEE Transactions on Bio-medical Engineering
https://www.readbyqxmd.com/read/28573481/copper-pyrithione-a-booster-biocide-induces-abnormal-muscle-and-notochord-architecture-in-zebrafish-embryogenesis
#11
Kelly M Almond, Louis D Trombetta
The metal pyrithiones, principally zinc (ZnPT) and copper (CuPT), are replacing tributyltin (TBT) as antifouling agents. Zebrafish embryos were exposed within the first hour after fertilization to 12 and 64 µg/L of CuPT for 24 h. Morphological abnormalities in notochord and muscle architecture were observed at 96 h post fertilization (hpf). TEM revealed abnormal electron dense deposits in the notochord sheath and muscle fiber degeneration in animals treated with 12 µg/L of CuPT. Embryos that were exposed to 64 µg/L of CuPT displayed severe muscle fiber degeneration including abnormal A and I band patterning and altered z disk arrangement...
June 1, 2017: Ecotoxicology
https://www.readbyqxmd.com/read/28522764/obesity-induced-discrepancy-between-contractile-and-metabolic-phenotypes-in-slow-and-fast-twitch-skeletal-muscles-of-female-obese-zucker-rats
#12
Luz M Acevedo, Ana I Raya, Rafael Ríos, Escolástico Aguilera-Tejero, Jose-Luis L Rivero
A clear picture of skeletal muscle adaptations to obesity and related comorbidities remains elusive. This study describes fiber-type characteristics (size, proportions, and oxidative enzyme activity) in two typical hind limb muscles with opposite structure and function in an animal model of genetic obesity. Lesser fiber diameter, fiber type composition, and histochemical succinic dehydrogenase activity (an oxidative marker) of muscle fiber types were assessed in slow- (soleus) and fast-twitch (tibialis cranialis) muscles of obese Zucker rats, and compared with age- (16 weeks) and sex-matched (females) lean Zucker rats (N=16/group)...
May 18, 2017: Journal of Applied Physiology
https://www.readbyqxmd.com/read/28480592/slow-myofiber-commitment-by-semaphorin-3a-secreted-from-myogenic-stem-cells
#13
Ryuichi Tatsumi, Takahiro Suzuki, Mai-Khoi Q Do, Yuki Ohya, Judy E Anderson, Ayumi Shibata, Mai Kawaguchi, Shunpei Ohya, Hideaki Ohtsubo, Wataru Mizunoya, Shoko Sawano, Yusuke Komiya, Riho Ichitsubo, Koichi Ojima, Shin-Ichiro Nishimatsu, Tsutomu Nohno, Yutaka Ohsawa, Yoshihide Sunada, Mako Nakamura, Mitsuhiro Furuse, Yoshihide Ikeuchi, Takanori Nishimura, Takeshi Yagi, Ronald E Allen
Recently, we found that resident myogenic stem satellite cells upregulate a multi-functional secreted protein, semaphorin 3A (Sema3A), exclusively at the early-differentiation phase in response to muscle injury; however, its physiological significance is still unknown. Here we show that Sema3A impacts slow-twitch fiber generation through a signaling pathway, cell-membrane receptor (neuropilin2-plexinA3) → myogenin-myocyte enhancer factor 2D → slow myosin heavy chain. This novel axis was found by small interfering RNA-transfection experiments in myoblast cultures, which also revealed an additional element that Sema3A-neuropilin1/plexinA1, A2 may enhance slow-fiber formation by activating signals that inhibit fast-myosin expression...
May 7, 2017: Stem Cells
https://www.readbyqxmd.com/read/28474872/is-the-stiffness-of-human-muscle-and-tendon-structures-related-to-muscle-fiber-composition-in-vivo
#14
Keitaro Kubo, Daisuke Miyazaki, Hideaki Yata, Shozo Shimoju, Masaji Okada, Naoya Tsunoda
AIM: The aim of the present study was to investigate the relationship between estimated muscle fiber composition (time-to-peak twitch torque; TPT) and muscle stiffness under passive and active conditions as well as stiffness of tendon structures in human plantar flexors. METHODS: TPT was assessed using supramaximal electrical stimulation. Active muscle stiffness in the medial gastrocnemius muscle was calculated based on changes in estimated muscle force and fascicle length during fast stretching after 50% maximal isometric contractions...
April 26, 2017: Journal of Sports Medicine and Physical Fitness
https://www.readbyqxmd.com/read/28161523/myomaker-is-required-for-the-fusion-of-fast-twitch-myocytes-in-the-zebrafish-embryo
#15
Weibin Zhang, Sudipto Roy
During skeletal muscle development, myocytes aggregate and fuse to form multinucleated muscle fibers. Inhibition of myocyte fusion is thought to significantly derail the differentiation of functional muscle fibers. Despite the purported importance of fusion in myogenesis, in vivo studies of this process in vertebrates are rather limited. Myomaker, a multipass transmembrane protein, has been shown to be the first muscle-specific fusion protein essential for myocyte fusion in the mouse. We have generated loss-of-function alleles in zebrafish myomaker, and found that fusion of myocytes into syncytial fast-twitch muscles was significantly compromised...
March 1, 2017: Developmental Biology
https://www.readbyqxmd.com/read/28028076/inorganic-nitrate-mimics-exercise-stimulated-muscular-fiber-type-switching-and-myokine-and-%C3%AE-aminobutyric-acid-release
#16
RANDOMIZED CONTROLLED TRIAL
Lee D Roberts, Tom Ashmore, Ben D McNally, Steven A Murfitt, Bernadette O Fernandez, Martin Feelisch, Ross Lindsay, Mario Siervo, Elizabeth A Williams, Andrew J Murray, Julian L Griffin
Exercise is an effective intervention for the prevention and treatment of type 2 diabetes. Skeletal muscle combines multiple signals that contribute to the beneficial effects of exercise on cardiometabolic health. Inorganic nitrate increases exercise efficiency, tolerance, and performance. The transcriptional regulator peroxisome proliferator-activated receptor γ coactivator 1α (PGC1α) coordinates the exercise-stimulated skeletal muscle fiber-type switch from glycolytic fast-twitch (type IIb) to oxidative slow-twitch (type I) and intermediate (type IIa) fibers, an effect reversed in insulin resistance and diabetes...
March 2017: Diabetes
https://www.readbyqxmd.com/read/27990244/electrically-and-hybrid-induced-muscle-activations-effects-of-muscle-size-and-fiber-type
#17
Kelly Stratton, Pouran D Faghri
The effect of three electrical stimulation (ES) frequencies (10, 35, and 50 Hz) on two muscle groups with different proportions of fast and slow twitch fibers (abductor pollicis brevis (APB) and vastus lateralis (VL)) was explored. We evaluated the acute muscles' responses individually and during hybrid activations (ES superimposed by voluntary activations). Surface electromyography (sEMG) and force measurements were evaluated as outcomes. Ten healthy adults (mean age: 24.4 ± 2.5 years) participated after signing an informed consent form approved by the university Institutional Review Board...
June 13, 2016: European Journal of Translational Myology
https://www.readbyqxmd.com/read/27974300/s-nitrosylation-and-s-glutathionylation-of-cys134-on-troponin-i-have-opposing-competitive-actions-on-ca-2-sensitivity-in-rat-fast-twitch-muscle-fibers
#18
T L Dutka, J P Mollica, C R Lamboley, V C Weerakkody, D W Greening, G S Posterino, R M Murphy, G D Lamb
Nitric oxide is generated in skeletal muscle with activity and decreases Ca(2+) sensitivity of the contractile apparatus, putatively by S-nitrosylation of an unidentified protein. We investigated the mechanistic basis of this effect and its relationship to the oxidation-induced increase in Ca(2+) sensitivity in mammalian fast-twitch (FT) fibers mediated by S-glutathionylation of Cys134 on fast troponin I (TnIf). Force-[Ca(2+)] characteristics of the contractile apparatus in mechanically skinned fibers were assessed by direct activation with heavily Ca(2+)-buffered solutions...
March 1, 2017: American Journal of Physiology. Cell Physiology
https://www.readbyqxmd.com/read/27799519/piperine-s-mitigation-of-obesity-and-diabetes-can-be-explained-by-its-up-regulation-of-the-metabolic-rate-of-resting-muscle
#19
Leonardo Nogara, Nariman Naber, Edward Pate, Marcella Canton, Carlo Reggiani, Roger Cooke
We identify a target for treating obesity and type 2 diabetes, the consumption of calories by an increase in the metabolic rate of resting skeletal muscle. The metabolic rate of skeletal muscle can be increased by shifting myosin heads from the super-relaxed state (SRX), with a low ATPase activity, to a disordered relaxed state (DRX), with a higher ATPase activity. The shift of myosin heads was detected by a change in fluorescent intensity of a probe attached to the myosin regulatory light chain in skinned skeletal fibers, allowing us to perform a high-throughput screen of 2,128 compounds...
November 15, 2016: Proceedings of the National Academy of Sciences of the United States of America
https://www.readbyqxmd.com/read/27792730/time-course-of-muscle-mass-loss-damage-and-proteolysis-in-gastrocnemius-following-unloading-and-reloading-implications-in-chronic-diseases
#20
Alba Chacon-Cabrera, Helena Lund-Palau, Joaquim Gea, Esther Barreiro
BACKGROUND: Disuse muscle atrophy is a major comorbidity in patients with chronic diseases including cancer. We sought to explore the kinetics of molecular mechanisms shown to be involved in muscle mass loss throughout time in a mouse model of disuse muscle atrophy and recovery following immobilization. METHODS: Body and muscle weights, grip strength, muscle phenotype (fiber type composition and morphometry and muscle structural alterations), proteolysis, contractile proteins, systemic troponin I, and mitochondrial content were assessed in gastrocnemius of mice exposed to periods (1, 2, 3, 7, 15 and 30 days) of non-invasive hindlimb immobilization (plastic splint, I cohorts) and in those exposed to reloading for different time-points (1, 3, 7, 15, and 30 days, R cohorts) following a seven-day period of immobilization...
2016: PloS One
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