Muscle function in a patient with Brody's disease

Ruiter, C.J. de; Wevers, Ron A.; Engelen, B.G.M. van; Verdijk, P. W. L.; Haan, A.L.M. de

doi:10.1002/(sici)1097-4598(199906)22:6<704::aid-mus6>3.0.co;2-z

Cited by 11 publications

(7 citation statements)

References 21 publications

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“…6), much more slowly than would be expected if ADP were the cause of the problem. It is also notable that patients suffering from myoadenylate deficiency, in whom high levels of ADP would be expected during muscle activity, do not show any obvious abnormalities in muscle function either at rest or when fatigued (de Ruiter et al 1999 b ) and muscle fatigue in adenylate kinase‐deficient mice is also reported to be little different to that of the wild‐type (Hancock et al 2005).…”

Section: Muscle Metabolites and Fatiguementioning

confidence: 99%

Changes in the force-velocity relationship of fatigued muscle: implications for power production and possible causes

Jones

2010

The Journal of Physiology

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Slowing of the contractile properties of skeletal muscle is one of the characteristic features of fatigue. First studied as a slowing of relaxation from an isometric contraction, it has become apparent that this slowing is indicative of functional changes in muscle responsible for a major loss of power with all its functional repercussions. There are three factors contributing to the loss of power in mammalian muscle at physiological temperatures, a decrease in isometric force, which mainly indicates a reduction in the number of active cross bridges, a slowing of the maximum velocity of unloaded shortening and an increased curvature of the force-velocity relationship. This latter change is a major cause of loss of power but is poorly understood. It is probably associated with an increase in the proportion of cross bridges in the low force state but there are no clear candidates for the metabolic changes that are responsible for this shift in cross bridge states. The possibility is discussed that the reduction in activating calcium that occurs with metabolically depleted muscle, alters the distribution of cross bridge states, affecting both shortening velocity and curvature. Muscle function in the body depends on a long chain of command starting from motivation, and even within the muscle fibres there are many steps between electrical activity in the surface and T tubular membranes and the molecular interaction of actin and myosin (Edwards, 1981). It would be wasteful of energy and resources to have certain parts of the chain 'over-engineered' so the different links in the chain are all likely to fail at about the same time when the system is stressed. It is unlikely, therefore, that there is any one site or mechanism of fatigue that applies to every situation. Thus the precise link which fails will vary depending on a range of factors including the type of activity, the type of muscle and the temperature, and when discussing fatigue it is important to specify the preparation and conditions under which the muscle is working. This short review will be concerned with mammalian, mainly human, muscle, undertaking metabolically demanding exercise at physiological temperatures of around 37• C. There have been a number of recent detailed reviews of muscle fatigue mainly David Jones graduated in Medical Biochemistry from the University of Birmingham and completed his PhD in Neurochemistry at the Institute of Psychiatry in London. With a family and house to support he changed fields and went to work at the Royal Postgraduate Medical School on basic muscle physiology and studies of patients with muscle problems. He continued these interests at UCL and in 1993 returned to Birmingham as Professor of Sport and Exercise Sciences; he is currently Emeritus Professor of Muscle Physiology at Manchester Metropolitan University. He has wide interests in muscle and exercise physiology but his abiding concern has been the changes in contractile function that occur with acute fatigue.

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Section: Muscle Metabolites and Fatiguementioning

confidence: 99%

Changes in the force-velocity relationship of fatigued muscle: implications for power production and possible causes

Jones

2010

The Journal of Physiology

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“…The results presented here and the subsequent discussion indicate that slowing of relaxation is accompanied by a change in cross bridge kinetics; this does not, however, exclude change in calcium reuptake from playing some role. Although Westerblad & Allen (1993, 1994a concluded that calcium movements did not play a role in slow relaxation, slow relaxation is seen when the sarcoplasmic reticulum calcium pump is inhibited with 2,5-di(tert-butyl)-1,4-benzohydroquinone (TBQ) in mouse muscles (Westerblad & Allen, 1994b) and in human muscle lacking the fast twitch isoform of the sarcoplasmic reticulum Ca 2+ -ATPase (Brody's disease; de Ruiter et al 1999c).…”

Section: Cross Bridge Cycling and Calcium Pumpingmentioning

confidence: 99%

Change in contractile properties of human muscle in relationship to the loss of power and slowing of relaxation seen with fatigue

Jones

Ruiter

Haan

2006

The Journal of Physiology

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Slow relaxation from an isometric contraction is characteristic of acutely fatigued muscle and is associated with a decrease in the maximum velocity of unloaded shortening (V max ) and both these phenomena might be due to a decreased rate of cross bridge detachment. We have compared the change in relaxation rate with that of various parameters of the force-velocity relationship over the course of an ischaemic series of fatiguing contractions and subsequent recovery using the human adductor pollicis muscle working in vivo at approximately 37• C in nine healthy young subjects. Maximal isometric force (F 0 ) decreased from 91.0 ± 1.9 to 58.3 ± 3.5 N (mean ± S.E.M.). Maximum power decreased from 53.6 ± 4.0 to 17.7 ± 1.2 (arbitrary units) while relaxation rate declined from −10.3 ± 0.38 to −2.56 ± 0.29 s −1 . V max showed a smaller relative change from 673 ± 20 to 560 ± 46 deg s −1 and with a time course that differed markedly from that of slowing of relaxation, showing very little change until late in the series of contractions. Curvature of the force-velocity relationship increased (a/F 0 decreasing from 0.22 ± 0.02 to 0.11 ± 0.02) with fatigue and with a time course that was similar to that of the loss of power and the slowing of relaxation. It is concluded that for human muscle working at a normal physiological temperature the change in curvature of the force-velocity relationship with fatigue is a major cause of loss of power and may share a common underlying mechanism with the slowing of relaxation from an isometric contraction.

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“…Functional studies on muscle samples from humans with Brody's disease have demonstrated that some patients exhibit reduced levels of SERCA1 protein content [105,106], while in other cases the levels of SERCA1 protein are unaltered, but there is a significant reduction (up to 80%) in the Ca 2+ pumping activity both in homogenates of muscle samples and in myotubes explanted from patients [99,106,107]. Chianina cattle pseudomyotonia, a disease similar to Brody's disease affecting cattle, is caused by the homozygous ATP2A1 p.R164H mutation [108].…”

Section: Brody's Diseasementioning

confidence: 99%

Ca2+ handling abnormalities in early-onset muscle diseases: Novel concepts and perspectives

Treves

Jungbluth

Voermans

et al. 2017

Seminars in Cell & Developmental Biology

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a b s t r a c tThe physiological process by which Ca 2+ is released from the sarcoplasmic reticulum is called excitationcontraction coupling; it is initiated by an action potential which travels deep into the muscle fiber where it is sensed by the dihydropyridine receptor, a voltage sensing L-type Ca 2+ channel localized on the transverse tubules. Voltage-induced conformational changes in the dihydropyridine receptor activate the ryanodine receptor Ca 2+ release channel of the sarcoplasmic reticulum. The released Ca 2+ binds to troponin C, enabling contractile thick-thin filament interactions. The Ca 2+ is subsequently transported back into the sarcoplasmic reticulum by specialized Ca 2+ pumps (SERCA), preparing the muscle for a new cycle of contraction. Although other proteins are involved in excitation-contraction coupling, the mechanism described above emphasizes the unique role played by the two Ca 2+ channels (the dihydropyridine receptor and the ryanodine receptor), the SERCA Ca 2+ pumps and the exquisite spatial organization of the membrane compartments endowed with the proteins responsible for this mechanism to function rapidly and efficiently. Research over the past two decades has uncovered the fine details of excitation-contraction coupling under normal conditions while advances in genomics have helped to identify mutations in novel genes in patients with neuromuscular disorders. While it is now clear that many patients with congenital muscle diseases carry mutations in genes encoding proteins directly involved in Ca 2+ homeostasis, it has become apparent that mutations are also present in genes encoding for proteins not thought to be directly involved in Ca 2+ regulation. Ongoing research in the field now focuses on understanding the functional effect of individual mutations, as well as understanding the role of proteins not specifically located in the sarcoplasmic reticulum which nevertheless are involved in Ca 2+ regulation or excitation-contraction coupling. The principal challenge for the future is the identification of drug targets that can be pharmacologically manipulated by small molecules, with the ultimate aim to improve muscle function and quality of life of patients with congenital muscle disorders. The aim of this review is to give an overview of the most recent findings concerning Ca 2+ dysregulation and its impact on muscle function in patients with congenital muscle disorders due to mutations in proteins involved in excitation-contraction coupling and more broadly on Ca 2+ homeostasis.

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Muscle function in a patient with Brody's disease

Cited by 11 publications

References 21 publications

Changes in the force-velocity relationship of fatigued muscle: implications for power production and possible causes

Changes in the force-velocity relationship of fatigued muscle: implications for power production and possible causes

Change in contractile properties of human muscle in relationship to the loss of power and slowing of relaxation seen with fatigue

Ca2+ handling abnormalities in early-onset muscle diseases: Novel concepts and perspectives

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