• vertebrate
  • Phylogenetic analysis of vertebrate TnI isoforms demonstrated that each of the muscle type-specific isoforms is more conserved across species than the three isoforms in one given species, indicating early diverged functions of the muscle fiber type-specific isoforms as well as the conservation of functions for each muscle fiber type. (wikipedia.org)
  • frog
  • Anatomical distribution of voltage-dependent membrane capacitance in frog skeletal muscle fibers. (rupress.org)
  • Components of nonlinear capacitance, or charge movement, were localized in the membranes of frog skeletal muscle fibers by studying the effect of 'detubulation' resulting from sudden withdrawal of glycerol from a glycerol-hypertonic solution in which the muscles had been immersed. (rupress.org)
  • Under the assumption that the single channel Ca 2+ current of a ryanodine receptor (RYR) is 0.5-2 pA, the results suggest that 1-5 active RYRs generate an average Ca 2+ spark in a frog intact muscle fiber. (rupress.org)
  • A quantitative model of the three-dimensional spread of Ca 2+ within the myoplasm of frog muscle was first developed for Ca 2+ release by an action potential ( Cannell and Allen, 1984 ). (rupress.org)
  • The main goal of this article is to adapt this model for simulations of Ca 2+ sparks in frog fibers and to find out whether the properties of the simulated sparks agree with those of measured sparks. (rupress.org)
  • Intracellular measurements of the resting potential were made in fibers of the frog sartorius muscle in solutions of varying salt composition and concentration to determine the effects of low ionic strength extracellular solutions on the resting potential. (rupress.org)
  • tendon
  • At the end of each muscle fiber, the outer layer of the sarcolemma combines with tendon fibers. (wikipedia.org)
  • The Golgi tendon organ (GTO) (also called Golgi organ, tendon organ, neurotendinous organ or neurotendinous spindle) is a proprioceptive sensory receptor organ that senses changes in muscle tension. (wikipedia.org)
  • The body of the organ is made up of strands of collagen that are connected at one end to the muscle fibers and at the other merge into the tendon proper. (wikipedia.org)
  • the axis-cylinders subdivide and end between the tendon fibers in irregular disks or varicosities (see figure). (wikipedia.org)
  • Tendon organs signal muscle force through the entire physiological range, not only at high strain. (wikipedia.org)
  • Until 1967 it was believed that Golgi tendon organs had a high threshold, only becoming active at high muscle forces. (wikipedia.org)
  • Consequently, it was thought that tendon organ input caused "weightlifting failure" through the clasp-knife reflex, which protected the muscle and tendons from excessive force. (wikipedia.org)
  • subunits
  • Our data evidenced an increase in NaV1.5 channels and the involvement of β subunits in the regulation of sodium current and fiber excitability. (deepdyve.com)
  • More recent studies reported that subunits of fast skeletal muscle troponin (fsTnI, fsTnT, fsTnC) were expressed at significant levels in smooth muscle cells of mouse blood vessels, bladder and bronchi. (wikipedia.org)
  • sarcolemma
  • They physically couple force-generating sarcomeres with the sarcolemma in striated muscle cells and are thus considered one of several "Achilles' heels" of skeletal muscle, a critical component of striated muscle morphology which, when compromised, is thought to directly contribute to the development of several distinct myopathies. (wikipedia.org)
  • A vinculin-containing cortical lattice in skeletal muscle: Transverse lattice elements ("costameres") mark sites of attachment between myofibrils and sarcolemma" (PDF). (wikipedia.org)
  • troponin
  • Experiments are designed to test some fundamental assumptions of the cross-bridge model as well as the role of the protein troponin C (TnC) in the regulation of calcium sensitivity in striated muscle. (wikipedia.org)
  • Troponin C has long been associated with the role of an on/off switch which turns a muscle 'on' by binding calcium or 'off' when it releases calcium. (wikipedia.org)
  • Troponin I, fast skeletal muscle is a protein that in humans is encoded by the TNNI2 gene. (wikipedia.org)
  • Crystallographic structure of fsTnI in troponin complex from chicken fast skeletal muscle showed an overall structure similar to that of cardiac troponin. (wikipedia.org)
  • The inhibitory region of fsTnI was resolved in skeletal troponin whereas it was invisible in the cardiac troponin crystal structure. (wikipedia.org)
  • Based on the crystal structure, a schematic illustration (Fig. 3) was proposed to show the conformational changes in troponin during muscle activation and relaxation. (wikipedia.org)
  • transverse
  • A reduction in this dependence in detubulated fibers suggested that sudden glycerol withdrawal isolated between 75 and 100% of the transverse tubules from the fiber surface. (rupress.org)
  • periphery
  • In muscle, plectin binds to the periphery of Z-discs, and along with the intermediate filament protein desmin, may form lateral linkages among neighboring Z-discs. (wikipedia.org)
  • While their cell bodies are found in the central nervous system (CNS), α motor neurons are also considered part of the somatic nervous system-a branch of the peripheral nervous system (PNS)-because their axons extend into the periphery to innervate skeletal muscles. (wikipedia.org)
  • calcium
  • Perturbing the calcium binding region of RLC through site-directed mutagenesis (D47A) decreased tension and stiffness in isolated, skinned skeletal muscle fibers, suggesting that the conformational change induced by calcium binding to RLC is functionally important. (wikipedia.org)
  • It is well established that RLC phosphorylation enhances myofilament sensitivity to calcium in isometrically-contracting, skinned cardiac fibers. (wikipedia.org)
  • sensitivity
  • We aimed to investigate how the size, number and location of LDs are associated with insulin sensitivity and muscle fiber types, and are regulated by aerobic training and treatment with an erythropoiesis-stimulating agent (ESA) in healthy young untrained males. (physiology.org)
  • Ca(2+) sensitivity of the contractile apparatus was significantly increased by 8 and 16 mM carnosine (increase in pCa(50) of 0.073 ± 0.007 and 0.116 ± 0.006 pCa units, respectively, in six type I fibers, and 0.063 ± 0.018 and 0.103 ± 0.013 pCa units, respectively, in five type II fibers). (biomedsearch.com)
  • Caffeine-induced force responses were potentiated by 8 mM carnosine in both type I and II fibers, with the potentiation in type II fibers being entirely explicable by the increase in Ca(2+) sensitivity of the contractile apparatus caused by carnosine. (biomedsearch.com)
  • However, the potentiation of caffeine-induced responses caused by carnosine in type I fibers was beyond that expected from the associated increase in Ca(2+) sensitivity of the contractile apparatus and suggestive of increased Ca(2+)-induced Ca(2+) release. (biomedsearch.com)
  • Thus increasing muscle carnosine content likely confers benefits to muscle performance in both fiber types by increasing the Ca(2+) sensitivity of the contractile apparatus and possibly also by aiding Ca(2+) release in type I fibers, helping to lessen or slow the decline in muscle performance during fatiguing stimulation. (biomedsearch.com)
  • Additionally, some horses have been shown to have insulin sensitivity, which improves glucose uptake by muscle cells and contributes to excessive glycogen storage that is already elevated secondary to the GSY1 mutation. (wikipedia.org)
  • denervation
  • These channels exhibited increased activation time constant (τm) and reduced conductance, similar to what has been observed in denervated muscles in vivo, where the density of NaV1.5 was increasing progressively after denervation. (deepdyve.com)
  • stiffness
  • While episodes of exertional rhabdomyolysis is one of the most frequent signs associated with affected horses (reported in ~37% of affected animals), other common signs include gait abnormalities, shifting lameness, muscle weakness that may result in an inability to rise, colic-like pain, and muscle fasciculation, atrophy, and/or stiffness (most commonly seen in the semimembranosus, semitendinosus, and longissimus muscles). (wikipedia.org)
  • deposition
  • Expression of neural agrin in transfected cells followed by its release and deposition on neighboring fibers induced multiple AChR aggregates. (rupress.org)
  • Type 2 PSSM is a category for disorders that lead to abnormal deposition of glycogen in the skeletal muscles of the horse that is not due to mutations in GSY1 or GBE1. (wikipedia.org)
  • sensory
  • They constitute the muscle spindle and are innervated by two axons, one sensory and one motor. (wikipedia.org)
  • It is by the sensory information from these two intrafusal fiber types that an individual is able to judge the position of their muscle, and the rate at which it is changing. (wikipedia.org)
  • When the muscle generates force, the sensory terminals are compressed. (wikipedia.org)
  • tension
  • The effects of partial extraction of TnC upon the tension-pCa relationship in rabbit skinned skeletal muscle fibers. (rupress.org)
  • Single skinned fibers were obtained from rabbit psoas muscles and were then placed in an experimental chamber containing relaxing solution maintained at 15 degrees C. Isometric tension was measured in solutions containing maximally and submaximally activating levels of free Ca2+ (a) in control fiber segments, (b) in the same segments after partial extraction of TnC, and finally (c) after recombination of TnC into the segments. (rupress.org)
  • The readdition of TnC to the extracted fiber segments resulted in a recovery of tension to near-control levels and in the return of the tension-pCa relation to its original position. (rupress.org)
  • genes
  • Three homologous genes have evolved in vertebrates, encoding three muscle type-specific isoforms of TnI. (wikipedia.org)
  • Sustained MyoD expression is necessary for retaining the expression of muscle-related genes. (wikipedia.org)
  • KAP1 is localized at muscle-related genes in myoblasts along with both MyoD and Mef2 (a myocyte transcription enhancer factor). (wikipedia.org)
  • The consequence of this coactivator/corepressor recruitment is silenced promoting regions on muscle genes. (wikipedia.org)
  • gene
  • The three muscle fiber type-specific TnI-TnT gene pairs were likely originated from a TnI-like ancestor gene that presumably duplicated to form a closely linked fast TnI-like and fast TnT-like gene pair. (wikipedia.org)
  • Myosin regulatory light chain 2, ventricular/cardiac muscle isoform (MLC-2) also known as the regulatory light chain of myosin (RLC) is a protein that in humans is encoded by the MYL2 gene. (wikipedia.org)
  • consistent
  • however, affected horses will show histological changes consistent with muscle damage at one month of age, and may also show elevations in creatine kinase (CK), an enzyme that elevates with muscle damage. (wikipedia.org)
  • stimulation
  • most control muscle fibers show phasic AP-induced Ca 2+ transients, while most fibers exposed to elevated D-glucose displayed biphasic Ca 2+ transients upon single field stimulation. (hindawi.com)
  • experimental
  • Our approach allows quantitative kinetic characterization of Foxo1 and Foxo3A nuclear-cytoplasmic movements in living muscle fibers under various experimental conditions. (physiology.org)
  • With approval of the Institutional Animal Care Committee of the University of Heidelberg (Heidelberg, Germany), we chose the well-established model of murine skinned fiber preparations, using an experimental protocol described before. (asahq.org)
  • Activation
  • Activation of the Foxo pathway leads to expression of atrogene products Atrogin-1/MAFbx and MuRF-1, proteins that are integral to the development of muscle atrophy ( 5 , 19 , 26 ). (physiology.org)
  • occurs
  • Signaling between nerve and muscle occurs at neuromuscular junctions (NMJs), which consist of specialized and precisely apposed pre- and postsynaptic structures separated by a synaptic cleft ( Sanes and Lichtman 1999 ). (rupress.org)
  • Fibrillation also occurs with individual skeletal muscle fibers. (wikipedia.org)
  • nuclear
  • In skeletal muscle, the transcription factors Foxo1 and Foxo3A control expression of proteins that mediate muscle atrophy, making the nuclear concentration and nuclear-cytoplasmic movements of Foxo1 and Foxo3A of therapeutic interest in conditions of muscle wasting. (physiology.org)
  • control
  • In control fibers it was strongly voltage dependent. (rupress.org)
  • There are more α-MNs in the spinal cord than in the brainstem, as the number of α-MNs is directly proportional to the amount of fine motor control in that muscle. (wikipedia.org)
  • For example, the muscles of a single finger have more α-MNs per fiber, and more α-MNs in total, than the muscles of the quadriceps, which allows for finer control of the force a finger applies. (wikipedia.org)