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Skeletal muscle relaxant

Jason Tallis, Rob S James, Frank Seebacher
Obesity can cause a decline in contractile function of skeletal muscle, thereby reducing mobility and promoting obesity-associated health risks. We reviewed the literature to establish the current state-of-knowledge of how obesity affects skeletal muscle contraction and relaxation. At a cellular level, the dominant effects of obesity are disrupted calcium signalling and 5'-adenosine monophosphate-activated protein kinase (AMPK) activity. As a result, there is a shift from slow to fast muscle fibre types. Decreased AMPK activity promotes the class II histone deacetylase (HDAC)-mediated inhibition of the myocyte enhancer factor 2 (MEF2)...
July 6, 2018: Journal of Experimental Biology
Amir Minerbi, Simon Vulfsons
BACKGROUND: The energy crisis hypothesis, which is a widely accepted model for the pathogenesis of myofascial pain, has been corroborated by experimental observations. However, the nature of the insult leading to the energy crisis remains elusive. A commonly cited model for this insult is the Cinderella hypothesis, suggesting that hierarchical recruitment of motor units leads to a disproportional load on small units, thus driving them towards an energy crisis. New findings cast doubt on this model, showing that in postural muscles motor units are recruited in rotation, rather than in a hierarchical order, precluding the formation of the so-called Cinderella units...
June 24, 2018: Rambam Maimonides Medical Journal
Chung-Hyun Cho, Keon Jin Lee, Eun Hui Lee
Skeletal muscle contracts or relaxes to maintain the body position and locomotion. For the contraction and relaxation of skeletal muscle, Ca2+ in the cytosol of skeletal muscle fibers acts as a switch to turn on and off a series of contractile proteins. The cytosolic Ca2+ level in skeletal muscle fibers is governed mainly by movement of Ca2+ between the cytosol and the sarcoplasmic reticulum (SR). Store-operated Ca2+ entry (SOCE), a Ca2+ entryway from the extracellular space to the cytosol, has gained a significant amount of attention from muscle physiologists...
June 14, 2018: BMB Reports
Hiroyuki Iwamoto
We studied the effect of myosin inhibitors, N-benzyl-p-toluenesulfonamide (BTS), blebbistatin, and butanedione monoxime (BDM) on X-ray diffraction patterns from rabbit psoas fibers under relaxing and contracting conditions. The first two inhibitors suppressed the contractile force almost completely at a 100 μM concentration, and a similar effect was obtained at 50 mM for BDM. However, still substantial changes were observed in the diffraction patterns upon calcium-activation of inhibited muscle fibers. (1) The 2nd actin layer-line reflection was enhanced normally, indicating that calcium binding to troponin and the subsequent movement of tropomyosin are not inhibited, (2) the myosin layer-line reflections became much weaker, and (3) the 1,1/1,0 intensity ratio of the equatorial reflections was increased...
2018: Biophysics and Physicobiology
Toru Tamaki, Ken Muramatsu, Masako Ikutomo, Naomi Oshiro, Hisae Hayashi, Masatoshi Niwa
Skeletal muscle fiber subtypes are differentially sensitive to diabetes-related pathology; For example, fast-twitch muscles exhibit severe decreases in contraction force while slow-twitch muscles demonstrate prolonged half-relaxation time. However, such alterations have only been examined after a relatively short period following diabetes onset, with no information available regarding muscle damage caused by longer disease periods (>20 weeks). This study examined alterations in the contractile properties of the medial gastrocnemius (fast-twitch) and soleus (slow-twitch) muscles, as well as morphological changes in their motor neurons 12 and 22 weeks after diabetes onset...
June 6, 2018: Anatomical Science International
Janelle Geist, Christopher W Ward, Aikaterini Kontrogianni-Konstantopoulos
Myosin binding protein-C slow (sMyBP-C) comprises a family of accessory proteins in skeletal muscles that bind both myosin and actin filaments. Herein, we examined the role of sMyBP-C in adult skeletal muscles using in vivo gene transfer and clustered regularly interspaced short palindromic repeats technology to knock down all known sMyBP-C variants. Our findings, confirmed in two different skeletal muscles, demonstrated efficient knockdown (KD) of sMyBP-C (>70%) resulting in notably decreased levels of thick, but not thin, filament proteins ranging from ∼50% for slow and fast myosin to ∼20% for myomesin...
June 6, 2018: FASEB Journal: Official Publication of the Federation of American Societies for Experimental Biology
Leonardo Nogueira, Breanna M Trisko, Frederico L Lima-Rosa, Jason Jackson, Helena Lund-Palau, Masahiro Yamaguchi, Ellen C Breen
KEY POINTS: Cigarette smoke components directly alter muscle fatigue resistance and intracellular muscle fibre Ca2+ handling independent of a change in lung structure. Changes in muscle vascular structure are associated with a depletion of satellite cells. Sarcoplasmic reticulum Ca2+ uptake is substantially impaired in myofibres during fatiguing contractions in mice treated with cigarette smoke extract. ABSTRACT: Cigarette smokers exhibit exercise intolerance before a decline in respiratory function...
May 23, 2018: Journal of Physiology
Qi Chen, Xianmin Zhang, Benliang Zhu
Understanding the optimal designs in nature is critical in bionics. This paper presents a method for designing the configuration of fusiform muscle with a maximum contractile displacement based on topology optimization methods. A nearly incompressible continuum constitutive model of skeletal muscle is utilized. The contractile displacement from the relaxed state to the contracted state is regarded as the objective function. To handle the numerical difficulties that result from the existence of element density, an energy interpolation equation is employed, and a modification of the constitutive model of skeletal muscle is proposed...
May 9, 2018: International Journal for Numerical Methods in Biomedical Engineering
Dorian Caudal, Isabelle Guinobert, Aude Lafoux, Valérie Bardot, César Cotte, Isabelle Ripoche, Pierre Chalard, Corinne Huchet
Valeriana officinalis L. root extracts are traditionally taken for their sedative and anxiolytic properties and are also used for muscle relaxation. Relaxant effects were clearly observed on smooth muscle whereas data on effects on skeletal muscle are scarce and inconsistent. The aim of this study was to assess whether a standardized extract (SE) of V. officinalis had myorelaxant effects by decreasing skeletal muscle strength and/or neuromuscular tone in mice. Mice received an acute dose of V. officinalis SE (2 or 5 g/kg per os) or tetrazepam (10 mg/kg ip), a standard myorelaxant drug...
April 2018: Journal of Traditional and Complementary Medicine
Yousef A Al-Dashti, Roberta R Holt, Charles L Stebbins, Carl L Keen, Robert M Hackman
An individual's diet affects numerous physiological functions and can play an important role in reducing the risk of cardiovascular disease. Epidemiological and clinical studies suggest that dietary flavanols can be an important modulator of vascular risk. Diets and plant extracts rich in flavanols have been reported to lower blood pressure, especially in prehypertensive and hypertensive individuals. Flavanols may act in part through signaling pathways that affect vascular function, nitric oxide availability, and the release of endothelial-derived relaxing and constricting factors...
May 2, 2018: Journal of the American College of Nutrition
Anand Thirupathi, Ricardo A Pinho
A large number of researches have led to a substantial growth of knowledge about exercise and oxidative stress. Initial investigations reported that physical exercise generates free radical-mediated damages to cells; however, in recent years, studies have shown that regular exercise can upregulate endogenous antioxidants and reduce oxidative damage. Yet, strenuous exercise perturbs the antioxidant system by increasing the reactive oxygen species (ROS) content. These alterations in the cellular environment seem to occur in an exercise type-dependent manner...
May 1, 2018: Journal of Physiology and Biochemistry
He Sun, Meng-Tao Xu, Xiao-Qi Wang, Meng-Hu Wang, Bao-Heng Wang, Feng-Zhe Wang, Shi-Nong Pan
Background: Magnetic resonance (MR) imaging provides a unique, noninvasive diagnostic platform to quantify the physiological and biochemical variables of skeletal muscle at rest. This study was to investigate the difference in thigh skeletal muscles between snowboarding halfpipe athletes and healthy volunteers via multiparametric MR imaging. Methods: A comparative study was conducted between 12 healthy volunteers and 14 snowboarding halfpipe athletes. MR scanning targeted the left leg at the level of the proximal thigh on a 3...
May 5, 2018: Chinese Medical Journal
Mohammad-Reza Ghovanloo, Mena Abdelsayed, Colin H Peters, Peter C Ruben
Skeletal muscle channelopathies, many of which are inherited as autosomal dominant mutations, include myotonia and periodic paralysis. Myotonia is defined by a delayed relaxation after muscular contraction, whereas periodic paralysis is defined by episodic attacks of weakness. One sub-type of periodic paralysis, known as hypokalemic periodic paralysis (hypoPP), is associated with low potassium levels. Interestingly, the P1158S missense mutant, located in the third domain S4-S5 linker of the "skeletal muscle", Nav1...
April 19, 2018: Scientific Reports
Ryan M Broxterman, Thomas J Hureau, Gwenael Layec, David E Morgan, Amber D Bledsoe, Jacob E Jessop, Markus Amann, Russell S Richardson
KEY POINTS: This investigation assessed the influence of group III/IV muscle afferents on small muscle mass exercise performance from a skeletal muscle bioenergetics perspective. Group III/IV muscle afferent feedback was attenuated with lumbar intrathecal fentanyl during intermittent isometric single-leg knee-extensor all-out exercise, while 31 P-MRS was used to assess skeletal muscle bioenergetics. Attenuation of group III/IV muscle afferent feedback improved exercise performance during the first minute of exercise, due to an increase in total ATP production with no change in the ATP cost of contraction...
April 12, 2018: Journal of Physiology
Thomas Ledowski, Simone Nißler, Manuel Wenk, Esther M Pogatzki-Zahn, Daniel Segelcke
Muscle ischaemia is frequently induced intraoperatively by i.e. a surgical tourniquet or during the re-grafting phase of a free muscle transplant. The resulting muscle cell damage may impact on postoperative recovery. Neuromuscular paralysis may mitigate the effects of ischaemia. After ethics approval, 25 male Sprague-Dawley rats were anaesthetized and randomly assigned to 1 of 4 groups: Sham operation, treatment with normal saline, treatment with rocuronium (muscle relaxant) 0.6 or 1 mg kg-1 , respectively...
April 11, 2018: Scientific Reports
Bruno Allard
In skeletal muscle fiber, excitation-contraction coupling corresponds to the sequence of events occurring from action potential firing to initiation of contraction by an increase in cytosolic Ca2+ . These events are elicited in response to excitation of the motor neuron which induces trains of action potentials in the muscle cell that spread along the sarcolemma and in depth along the T-tubule membrane. Depolarization of the T-tubule membrane induces a conformational change in a protein complex, called the dihydropyridine receptor, which opens a calcium channel anchored in the membrane of the sarcoplasmic reticulum, called the ryanodine receptor, in charge of release of Ca2+ ions that activate contractile proteins...
May 2018: Neuromuscular Disorders: NMD
Kerryanne V Winters, Olivier Reynaud, Dmitry S Novikov, Els Fieremans, Sungheon Gene Kim
PURPOSE: To measure the microstructural changes during skeletal muscle growth and progressive pathologies using the random permeable model with diffusion MRI, and compare findings to conventional imaging modalities such as three-point Dixon and T2 imaging. METHODS: In vivo and ex vivo DTI experiments with multiple diffusion times (20-700 ms) were completed on wild-type (n = 22) and muscle-dystrophic mdx mice (n = 8) at various developmental time points. The DTI data were analyzed with the random permeable model framework that provides estimates of the unrestricted diffusion coefficient (D0 ), membrane surface-to-volume ratio (S/V), and membrane permeability (κ)...
March 25, 2018: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
Hanne Laakso, Galina Wirth, Petra Korpisalo, Elias Ylä-Herttuala, Shalom Michaeli, Seppo Ylä-Herttuala, Timo Liimatainen
The identification of areas with regenerative potential in ischemic tissues would allow the targeting of treatments supporting tissue recovery. The regeneration process involves the activation of several cellular and molecular responses which could be detected using magnetic resonance imaging (MRI). However, to date, magnetic resonance (MR) relaxation parameters have received little attention in the diagnosis and follow-up of limb ischemia. The purpose of this study was to evaluate the feasibility of different MRI relaxation and diffusion tensor imaging parameters in the detection of areas showing early signs of regeneration in ischemic mouse skeletal muscles...
May 2018: NMR in Biomedicine
Alison M Barnard, Rebecca J Willcocks, Erika L Finanger, Michael J Daniels, William T Triplett, William D Rooney, Donovan J Lott, Sean C Forbes, Dah-Jyuu Wang, Claudia R Senesac, Ann T Harrington, Richard S Finkel, Barry S Russman, Barry J Byrne, Gihan I Tennekoon, Glenn A Walter, H Lee Sweeney, Krista Vandenborne
OBJECTIVE: To provide evidence for quantitative magnetic resonance (qMR) biomarkers in Duchenne muscular dystrophy by investigating the relationship between qMR measures of lower extremity muscle pathology and functional endpoints in a large ambulatory cohort using a multicenter study design. METHODS: MR spectroscopy and quantitative imaging were implemented to measure intramuscular fat fraction and the transverse magnetization relaxation time constant (T2) in lower extremity muscles of 136 participants with Duchenne muscular dystrophy...
2018: PloS One
Shiteng Suo, Lan Zhang, Hui Tang, Qihong Ni, Suqin Li, Haimin Mao, Xiangyu Liu, Shengyun He, Jianxun Qu, Qing Lu, Jianrong Xu
BACKGROUND: Noninvasive cardiovascular magnetic resonance (CMR) techniques including arterial spin labeling (ASL), blood oxygenation level-dependent (BOLD), and intravoxel incoherent motion (IVIM), are capable of measuring tissue perfusion-related parameters. We sought to evaluate and compare these three CMR techniques in characterizing skeletal muscle perfusion in lower extremities and to investigate their abilities to diagnose and assess the severity of peripheral arterial disease (PAD)...
March 19, 2018: Journal of Cardiovascular Magnetic Resonance
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