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Castro AA, Garland T, Ahmed S, Holt NC. Trade-offs in muscle physiology in selectively bred high runner mice. J Exp Biol 2022; 225:285903. [PMID: 36408738 PMCID: PMC9789404 DOI: 10.1242/jeb.244083] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2022] [Accepted: 10/25/2022] [Indexed: 11/22/2022]
Abstract
A trade-off between locomotor speed and endurance occurs in various taxa, and is thought to be underpinned by a muscle-level trade-off. Among four replicate high runner (HR) lines of mice, selectively bred for voluntary wheel-running behavior, a negative correlation between average running speed and time spent running has evolved. We hypothesize that this trade-off is due to changes in muscle physiology. We studied the HR lines at generation 90, at which time one line (L3) is fixed for the mini-muscle phenotype, another is polymorphic (L6) and the others (L7, L8) lack mini-muscle individuals. We used in situ preparations to quantify the contractile properties of the triceps surae muscle complex. Maximal shortening velocity varied significantly, being lowest in mini-muscle mice (L3 mini=25.2 mm s-1, L6 mini=25.5 mm s-1), highest in normal-muscle mice L6 and L8 (40.4 and 50.3 mm s-1, respectively) and intermediate in normal-muscle L7 mice (37.2 mm s-1). Endurance, measured both as the slope of the decline in force and the proportion of initial force that could be sustained, also varied significantly. The slope was shallowest in mini-muscle mice (L3 mini=-0.00348, L6 mini=-0.00238), steepest in lines L6 and L8 (-0.01676 and -0.01853), and intermediate in L7 (-0.01145). Normalized sustained force was highest in mini-muscle mice (L3 mini=0.98, L6 mini=0.92) and lowest in L8 (0.36). There were significant, negative correlations between velocity and endurance metrics, indicating a muscle-level trade-off. However, this muscle-level trade-off does not seem to underpin the organismal-level speed and endurance trade-off previously reported as the ordering of the lines is reversed: the lines that run the fastest for the least time have the lowest muscle complex velocity and highest endurance.
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Affiliation(s)
- Alberto A. Castro
- Department of Evolution, Ecology, and Organismal Biology, University of California, Riverside, Riverside, CA 92521, USA
| | - Theodore Garland
- Department of Evolution, Ecology, and Organismal Biology, University of California, Riverside, Riverside, CA 92521, USA
| | - Saad Ahmed
- Department of Evolution, Ecology, and Organismal Biology, University of California, Riverside, Riverside, CA 92521, USA
| | - Natalie C. Holt
- Department of Evolution, Ecology, and Organismal Biology, University of California, Riverside, Riverside, CA 92521, USA,Author for correspondence ()
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2
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Plaideau C, Lai YC, Kviklyte S, Zanou N, Löfgren L, Andersén H, Vertommen D, Gailly P, Hue L, Bohlooly-Y M, Hallén S, Rider MH. Effects of pharmacological AMP deaminase inhibition and Ampd1 deletion on nucleotide levels and AMPK activation in contracting skeletal muscle. ACTA ACUST UNITED AC 2015; 21:1497-1510. [PMID: 25459662 DOI: 10.1016/j.chembiol.2014.09.013] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2014] [Revised: 08/08/2014] [Accepted: 09/03/2014] [Indexed: 11/28/2022]
Abstract
AMP-activated protein kinase (AMPK) plays a central role in regulating metabolism and energy homeostasis. It achieves its function by sensing fluctuations in the AMP:ATP ratio. AMP deaminase (AMPD) converts AMP into IMP, and the AMPD1 isoenzyme is expressed in skeletal muscles. Here, effects of pharmacological inhibition and genetic deletion of AMPD were examined in contracting skeletal muscles. Pharmacological AMPD inhibition potentiated rises in AMP, AMP:ATP ratio, AMPK Thr172, and acetyl-CoA carboxylase (ACC) Ser218 phosphorylation induced by electrical stimulation, without affecting glucose transport. In incubated extensor digitorum longus and soleus muscles from Ampd1 knockout mice, increases in AMP levels and AMP:ATP ratio by electrical stimulation were potentiated considerably compared with muscles from wild-type mice, whereas enhanced AMPK activation was moderate and only observed in soleus, suggesting control by factors other than changes in adenine nucleotides. AMPD inhibitors could be useful tools for enhancing AMPK activation in cells and tissues during ATP-depletion.
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3
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Zanou N, Schakman O, Louis P, Ruegg UT, Dietrich A, Birnbaumer L, Gailly P. Trpc1 ion channel modulates phosphatidylinositol 3-kinase/Akt pathway during myoblast differentiation and muscle regeneration. J Biol Chem 2012; 287:14524-34. [PMID: 22399301 DOI: 10.1074/jbc.m112.341784] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
We previously showed in vitro that calcium entry through Trpc1 ion channels regulates myoblast migration and differentiation. In the present work, we used primary cell cultures and isolated muscles from Trpc1(-/-) and Trpc1(+/+) murine model to investigate the role of Trpc1 in myoblast differentiation and in muscle regeneration. In these models, we studied regeneration consecutive to cardiotoxin-induced muscle injury and observed a significant hypotrophy and a delayed regeneration in Trpc1(-/-) muscles consisting in smaller fiber size and increased proportion of centrally nucleated fibers. This was accompanied by a decreased expression of myogenic factors such as MyoD, Myf5, and myogenin and of one of their targets, the developmental MHC (MHCd). Consequently, muscle tension was systematically lower in muscles from Trpc1(-/-) mice. Importantly, the PI3K/Akt/mTOR/p70S6K pathway, which plays a crucial role in muscle growth and regeneration, was down-regulated in regenerating Trpc1(-/-) muscles. Indeed, phosphorylation of both Akt and p70S6K proteins was decreased as well as the activation of PI3K, the main upstream regulator of the Akt. This effect was independent of insulin-like growth factor expression. Akt phosphorylation also was reduced in Trpc1(-/-) primary myoblasts and in control myoblasts differentiated in the absence of extracellular Ca(2+) or pretreated with EGTA-AM or wortmannin, suggesting that the entry of Ca(2+) through Trpc1 channels enhanced the activity of PI3K. Our results emphasize the involvement of Trpc1 channels in skeletal muscle development in vitro and in vivo, and identify a Ca(2+)-dependent activation of the PI3K/Akt/mTOR/p70S6K pathway during myoblast differentiation and muscle regeneration.
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Affiliation(s)
- Nadège Zanou
- Laboratory of Cell Physiology, Institute of Neuroscience, Université Catholique de Louvain, 55/40 av. Hippocrate, 1200 Brussels, Belgium.
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4
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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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5
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Zanou N, Shapovalov G, Louis M, Tajeddine N, Gallo C, Van Schoor M, Anguish I, Cao ML, Schakman O, Dietrich A, Lebacq J, Ruegg U, Roulet E, Birnbaumer L, Gailly P. Role of TRPC1 channel in skeletal muscle function. Am J Physiol Cell Physiol 2010; 298:C149-62. [PMID: 19846750 PMCID: PMC2806157 DOI: 10.1152/ajpcell.00241.2009] [Citation(s) in RCA: 95] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2009] [Accepted: 10/19/2009] [Indexed: 11/22/2022]
Abstract
Skeletal muscle contraction is reputed not to depend on extracellular Ca2+. Indeed, stricto sensu, excitation-contraction coupling does not necessitate entry of Ca2+. However, we previously observed that, during sustained activity (repeated contractions), entry of Ca2+ is needed to maintain force production. In the present study, we evaluated the possible involvement of the canonical transient receptor potential (TRPC)1 ion channel in this entry of Ca2+ and investigated its possible role in muscle function. Patch-clamp experiments reveal the presence of a small-conductance channel (13 pS) that is completely lost in adult fibers from TRPC1(-/-) mice. The influx of Ca2+ through TRPC1 channels represents a minor part of the entry of Ca(2+) into muscle fibers at rest, and the activity of the channel is not store dependent. The lack of TRPC1 does not affect intracellular Ca2+ concentration ([Ca2+](i)) transients reached during a single isometric contraction. However, the involvement of TRPC1-related Ca2+ entry is clearly emphasized in muscle fatigue. Indeed, muscles from TRPC1(-/-) mice stimulated repeatedly progressively display lower [Ca2+](i) transients than those observed in TRPC1(+/+) fibers, and they also present an accentuated progressive loss of force. Interestingly, muscles from TRPC1(-/-) mice display a smaller fiber cross-sectional area, generate less force per cross-sectional area, and contain less myofibrillar proteins than their controls. They do not present other signs of myopathy. In agreement with in vitro experiments, TRPC1(-/-) mice present an important decrease of endurance of physical activity. We conclude that TRPC1 ion channels modulate the entry of Ca(2+) during repeated contractions and help muscles to maintain their force during sustained repeated contractions.
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Affiliation(s)
- Nadège Zanou
- Laboratory of Cell Physiology, Inst. of Neuroscience, Université Catholique de Louvain, 55/40 av. Hippocrate, 1200 Brussels, Belgium.
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6
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Place N, Yamada T, Zhang SJ, Westerblad H, Bruton JD. High temperature does not alter fatigability in intact mouse skeletal muscle fibres. J Physiol 2009; 587:4717-24. [PMID: 19675072 DOI: 10.1113/jphysiol.2009.176883] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
Intense activation of skeletal muscle results in fatigue development, which involves impaired function of the muscle cells resulting in weaker and slower contractions. Intense muscle activity also results in increased heat production and muscle temperature may rise by up to 6 degrees C. Hyperthermia is associated with impaired exercise performance in vivo and recent studies have shown contractile dysfunction and premature fatigue development in easily fatigued muscle fibres stimulated at high temperatures and these defects were attributed to oxidative stress. Here we studied whether fatigue-resistant soleus fibres stimulated at increased temperature show premature fatigue development and whether increasing the level of oxidative stress accelerates fatigue development. Intact single fibres or small bundles of soleus fibres were fatigued by 600 ms tetani given at 2 s intervals at 37 degrees C and 43 degrees C, which is the highest temperature the muscle would experience in vivo. Tetanic force in the unfatigued state was not significantly different at the two temperatures. With 100 fatiguing tetani, force decreased by approximately 15% at both temperatures; the free cytosolic [Ca(2+)] (assessed with indo-1) showed a similar approximately 10% decrease at both temperatures. The oxidative stress during fatigue at 43 degrees C was increased by application of 10 microM hydrogen peroxide or tert-butyl hydroperoxide and this did not cause premature fatigue development. In summary, fatigue-resistant muscle fibres do not display impaired contractility and fatigue resistance at the highest temperature that mammals, including humans, would experience in vivo. Thus, intrinsic defects in fatigue-resistant muscle fibres cannot explain the decreased physical performance at high temperatures.
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Affiliation(s)
- Nicolas Place
- Department of Physiology and Pharmacology, Karolinska Institute, Stockholm S-171 77, Sweden
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7
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Calderón JC, Bolaños P, Torres SH, Rodríguez-Arroyo G, Caputo C. Different fibre populations distinguished by their calcium transient characteristics in enzymatically dissociated murine flexor digitorum brevis and soleus muscles. J Muscle Res Cell Motil 2009; 30:125-37. [DOI: 10.1007/s10974-009-9181-1] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2009] [Accepted: 05/20/2009] [Indexed: 11/30/2022]
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8
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Agbulut O, Vignaud A, Hourde C, Mouisel E, Fougerousse F, Butler-Browne GS, Ferry A. Slow myosin heavy chain expression in the absence of muscle activity. Am J Physiol Cell Physiol 2008; 296:C205-14. [PMID: 18945940 DOI: 10.1152/ajpcell.00408.2008] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Innervation has been generally accepted to be a major factor involved in both triggering and maintaining the expression of slow myosin heavy chain (MHC-1) in skeletal muscle. However, previous findings from our laboratory have suggested that, in the mouse, this is not always the case (30). Based on these results, we hypothesized that neurotomy would not markedly reduced the expression of MHC-1 protein in the mouse soleus muscles. In addition, other cellular, biochemical, and functional parameters were also studied in these denervated soleus muscles to complete our study. Our results show that denervation reduced neither the relative amount of MHC-1 protein, nor the percentage of muscle fibers expressing MHC-1 protein (P > 0.05). The fact that MHC-1 protein did not respond to muscle inactivity was confirmed in three different mouse strains (129/SV, C57BL/6, and CD1). In contrast, all of the other histological, biochemical, and functional muscle parameters were markedly altered by denervation. Cross-sectional area (CSA) of muscle fibers, maximal tetanic isometric force, maximal velocity of shortening, maximal power, and citrate synthase activity were all reduced in denervated muscles compared with innervated muscles (P < 0.05). Contraction and one-half relaxation times of the twitch were also increased by denervation (P < 0.05). Addition of tenotomy to denervation had no further effect on the relative expression of MHC-1 protein (P > 0.05), despite a greater reduction in CSA and citrate synthase activity (P < 0.05). In conclusion, a deficit in neural input leads to marked atrophy and reduction in performance in mouse soleus muscles. However, the maintenance of the relative expression of slow MHC protein is independent of neuromuscular activity in mice.
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Affiliation(s)
- O Agbulut
- EA300, Université Paria Diderot, Paris, France
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9
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Vignaud A, Fougerousse F, Mouisel E, Guerchet N, Hourde C, Bacou F, Butler-Browne GS, Chatonnet A, Ferry A. Genetic inactivation of acetylcholinesterase causes functional and structural impairment of mouse soleus muscles. Cell Tissue Res 2008; 333:289-96. [DOI: 10.1007/s00441-008-0640-6] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2008] [Revised: 05/06/2008] [Accepted: 05/08/2008] [Indexed: 11/28/2022]
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10
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Zhang SJ, Bruton JD, Katz A, Westerblad H. Limited oxygen diffusion accelerates fatigue development in mouse skeletal muscle. J Physiol 2006; 572:551-9. [PMID: 16455685 PMCID: PMC1779680 DOI: 10.1113/jphysiol.2005.104521] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Revised: 12/27/2005] [Accepted: 01/31/2006] [Indexed: 01/03/2023] Open
Abstract
Isolated whole skeletal muscles fatigue more rapidly than isolated single muscle fibres. We have now employed this difference to study mechanisms of skeletal muscle fatigue. Isolated whole soleus and extensor digitorum longus (EDL) muscles were fatigued by repeated tetanic stimulation while measuring force production. Neither application of 10 mm lactic acid nor increasing the [K(+)] of the bath solution from 5 to 10 mm had any significant effect on the rate of force decline during fatigue induced by repeated brief tetani. Soleus muscles fatigued slightly faster during continuous tetanic stimulation in 10 mm[K(+)]. Inhibition of mitochondrial respiration with cyanide resulted in a faster fatigue development in both soleus and EDL muscles. Single soleus muscle fibres were fatigued by repeated tetani while measuring force and myoplasmic free [Ca(2+)] ([Ca(2+)](i)). Under control conditions, the single fibres were substantially more fatigue resistant than the whole soleus muscles; tetanic force at the end of a series of 100 tetani was reduced by about 10% and 50%, respectively. However, in the presence of cyanide, fatigue developed at a similar rate in whole muscles and single fibres, and tetanic force at the end of fatiguing stimulation was reduced by approximately 80%. The force decrease in the presence of cyanide was associated with a approximately 50% decrease in tetanic [Ca(2+)](i), compared with an increase of approximately 20% without cyanide. In conclusion, lactic acid or [K(+)] has little impact on fatigue induced by repeated tetani, whereas hypoxia speeds up fatigue development and this is mainly due to an impaired Ca(2+) release from the sarcoplasmic reticulum.
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Affiliation(s)
- Shi-Jin Zhang
- Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden
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11
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Bruton JD, Dahlstedt AJ, Abbate F, Westerblad H. Mitochondrial function in intact skeletal muscle fibres of creatine kinase deficient mice. J Physiol 2004; 552:393-402. [PMID: 14561823 PMCID: PMC2343388 DOI: 10.1113/jphysiol.2003.050732] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
Creatine kinase (CK) has a central role in skeletal muscle, acting as a fast energy buffer and shuttle between sites of energy production (mitochondria) and consumption (cross-bridges and ion pumps). Unexpectedly, isolated fast-twitch skeletal muscle cells of mice deficient in both cytosolic and mitochondrial CK (CK-/-) are highly fatigue resistant during stimulation protocols that stress aerobic metabolism. We have now studied different aspects of mitochondrial function in CK-/- skeletal muscle. Intact, single fibres of flexor digitorum brevis (FDB) muscles were fatigued by repeated tetanic stimulation (70 Hz, 350 ms duration, duty cycle 0.14). Under control conditions, CK-/- FDB fibres were more fatigue resistant than wild-type fibres. However, after mitochondrial inhibition with cyanide, force declined markedly faster in CK-/- fibres than in wild-type fibres. The rapid force decline in CK-/- fibres was not due to decreased myoplasmic [Ca2+] during tetani (measured with indo-1), which in these fibres remained virtually constant during fatigue in the presence of cyanide. Intact, single fibres of highly oxidative soleus muscles were fatigued by repeated tetani (50 Hz, 500 ms duration, duty cycle 0.5). All CK-/- soleus fibres tested (n = 9) produced > 40 % force at the end of the fatiguing stimulation period (500 tetani), whereas force fell to < 40 % before 500 tetani in two of three wild-type fibres. Mitochondrial [Ca2+] (measured with rhod-2 and confocal microscopy) increased during repeated tetanic stimulation in CK-/- but not in wild-type FDB fibres. In conclusion, mitochondria and energy shuttling operate effectively in CK-/- fibres and this is associated with an increase in mitochondrial [Ca2+].
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Affiliation(s)
- Joseph D Bruton
- Department of Physiology and Pharmacology, Karolinska Institutet, 171 77 Stockholm, Sweden
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12
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Lännergren J, Bruton JD. Mitochondrial Ca2+ in mouse soleus single muscle fibres in response to repeated tetanic contractions. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2004; 538:557-62; discussion 562. [PMID: 15098698 DOI: 10.1007/978-1-4419-9029-7_49] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/29/2023]
Affiliation(s)
- Jan Lännergren
- Department of Physiology and Pharmacology, Karolinska Institutet, S-171 77 Stockholm, Sweden
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13
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Stelzer JE, Widrick JJ. Effect of hindlimb suspension on the functional properties of slow and fast soleus fibers from three strains of mice. J Appl Physiol (1985) 2003; 95:2425-33. [PMID: 12949008 DOI: 10.1152/japplphysiol.01091.2002] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Cross-sectional area (CSA), peak Ca2+-activated force (Po), fiber specific force (Po/CSA), and unloaded shortening velocity (Vo) were measured in slow-twitch [containing type I myosin heavy chain (MHC)] and fast-twitch (containing type II MHC) chemically skinned soleus muscle fiber segments obtained from three strains of weight-bearing and 7-day hindlimb-suspended (HS) mice. HS reduced soleus slow MHC content (from approximately 50 to approximately 33%) in CBA/J and ICR strains without affecting slow MHC content in C57BL/6 mice ( approximately 20% of total MHC). Two-way ANOVA revealed HS-induced reductions in CSA, Po, and Po/CSA of slow and fast fibers from all strains. Fiber Vo was elevated post-HS, but not consistently across strains. No MHC x HS treatment interactions were observed for any variable for C57BL/6 and CBA/J mice, and the two significant interactions found for the ICR strain (CSA, Po) appeared related to inherent pre-HS differences in slow vs. fast fiber CSA. In the mouse HS models studied here, fiber atrophy and contractile dysfunction were partially dependent on animal strain and generally independent of fiber MHC isoform content.
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MESH Headings
- Adaptation, Physiological
- Animals
- Biomechanical Phenomena
- Body Weight/physiology
- Calcium/physiology
- Electrophoresis, Polyacrylamide Gel
- Hindlimb Suspension/physiology
- Mice
- Mice, Inbred C57BL
- Mice, Inbred CBA
- Mice, Inbred ICR
- Muscle Fibers, Fast-Twitch/physiology
- Muscle Fibers, Slow-Twitch/physiology
- Muscle, Skeletal/cytology
- Muscle, Skeletal/physiology
- Myosin Heavy Chains/chemistry
- Myosin Heavy Chains/metabolism
- Species Specificity
- Transducers, Pressure
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Affiliation(s)
- Julian E Stelzer
- Department of Exercise and Sport Science, Oregon State University, Corvallis, OR 97331, USA
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14
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Bruton J, Tavi P, Aydin J, Westerblad H, Lännergren J. Mitochondrial and myoplasmic [Ca2+] in single fibres from mouse limb muscles during repeated tetanic contractions. J Physiol 2003; 551:179-90. [PMID: 12815178 PMCID: PMC2343157 DOI: 10.1113/jphysiol.2003.043927] [Citation(s) in RCA: 70] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
Previous studies on single fast-twitch fibres from mouse toe muscles have shown marked fatigue-induced changes in the free myoplasmic [Ca2+] ([Ca2+]i), while mitochondrial [Ca2+] remained unchanged. We have now investigated whether muscle fibres from the legs of mice respond in a similar way. Intact, single fibres were dissected from the soleus and extensor digitorum longus (EDL) muscles of adult mice. To measure [Ca2+]i, indo-1 was injected into the isolated fibres. Mitochondrial [Ca2+] was measured using Rhod-2 and confocal laser microscopy. Fatigue was induced by up to 1000 tetanic contractions (70 Hz) given at 2 s intervals. In soleus fibres, there was no significant decrease in tetanic [Ca2+]i at the end of the fatiguing stimulation, whereas tetanic force was significantly reduced by about 30 %. In 10 out of 14 soleus fibres loaded with Rhod-2 and subjected to fatigue, mitochondrial [Ca2+] increased to a maximum after about 50 tetani; this increase was fully reversed within 20 min after the end of stimulation. The force-frequency curve of the non-responding soleus fibres was shifted to higher frequencies compared to that of the responding fibres. In addition, eight out of nine Rhod-2-loaded EDL fibres showed similar changes in mitochondrial [Ca2+] during and after a period of fatiguing stimulation. The stimulation-induced increase in mitochondrial [Ca2+] was reduced when mitochondria were depolarised by application of carbonyl cyanide 4-(trifluoromethoxy)phenylhydrazone, whereas it was increased by application of an inhibitor of the mitochondrial Na+/Ca2+ exchange (CGP-37157). In conclusion, isolated slow-twitch muscle fibres show only modest changes in tetanic force and [Ca2+]i during repeated contractions. The increase in mitochondrial Ca2+ does not appear to be essential for activation of mitochondrial ATP production, nor does it cause muscle damage.
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Affiliation(s)
- Joseph Bruton
- Department of Physiology and Pharmacology, Karolinska Institutet, 171 77 Stockholm, Sweden.
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15
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Raymackers JM, Debaix H, Colson-Van Schoor M, De Backer F, Tajeddine N, Schwaller B, Gailly P, Gillis JM. Consequence of parvalbumin deficiency in the mdx mouse: histological, biochemical and mechanical phenotype of a new double mutant. Neuromuscul Disord 2003; 13:376-87. [PMID: 12798793 DOI: 10.1016/s0960-8966(03)00031-2] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We tested the hypothesis whether the mild dystrophy in mdx mice could result from the contribution of the cytosolic calcium buffer parvalbumin in maintaining a normal cytosolic [Ca2+]i, in spite of an increased passive Ca2+ influx. By crossing mdx mice with parvalbumin-deficient mice, double mutant mice, lacking both dystrophin and parvalbumin, were obtained. Though resting cytosolic [Ca2+]i and total calcium content were similar to that of mdx muscles, this new animal model presented a slightly more severe phenotype than the mdx mouse. Muscle pseudo-hypertrophy, the density of myotubes and of centronucleated fibres as well as the loss of IIB fibres were all increased in parvalbumin-deficient mdx mice. Many of these deficits were overcome in late adulthood, albeit fibrosis was clearly more pronounced than in mdx muscles. At 90 days, parvalbumin-deficient mdx mice showed higher levels of creatine phosphokinase and lower muscle strength, in vivo, than mdx mice. Isometric tension of isolated muscle was reduced, but the susceptibility to eccentric contraction was not increased. The slight aggravation of muscle dystrophy observed in mdx mice deprived of parvalbumin cannot explain the severity of the affection observed in xmd dogs and Duchenne dystrophy patients where parvalbumin is constitutively not expressed.
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Affiliation(s)
- J M Raymackers
- Department of Physiology and Pharmacology, Catholic University of Louvain, B-1200 Brussels, Belgium
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Fougerousse F, Gonin P, Durand M, Richard I, Raymackers JM. Force impairment in calpain 3-deficient mice is not correlated with mechanical disruption. Muscle Nerve 2003; 27:616-23. [PMID: 12707983 DOI: 10.1002/mus.10368] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Defects in human calpain 3 are responsible for limb-girdle muscular dystrophy type 2A, an autosomal-recessive disorder characterized mainly by late-onset proximal muscular atrophy. A corresponding murine model has previously been generated by gene targeting. In this report, muscular activity of calpain 3-deficient (capn3(-/-)) mice was evaluated at different ages. Growth curves showed a progressive global muscular atrophy. Histological examination throughout the lifespan of mice confirmed the dystrophic lesions. Whole animal tests showed only a mild significant impairment of the forelimbs. Studies of the mechanical properties of selected isolated fast- and slow-twitch muscles demonstrated that slow-twitch muscles were significantly weaker in capn3(-/-) mice than in wild-type mice. Three different tests showed that there was no membrane disruption, suggesting a nonmechanical etiology of capn3(-/-) mice dystrophy. These findings are consistent with a mechanism involving signaling systems.
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Affiliation(s)
- Françoise Fougerousse
- Centre National de la Recherche Scientifique, Unité Mixte de Recherche 8115-Généthon, 1 rue de l'Internationale, BP 60, 91002 Evry, France.
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17
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Qu Z, Huard J. Matching host muscle and donor myoblasts for myosin heavy chain improves myoblast transfer therapy. Gene Ther 2000; 7:428-37. [PMID: 10694825 DOI: 10.1038/sj.gt.3301103] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Intensive efforts have been made to develop an effective therapy for Duchenne muscular dystrophy (DMD). Although myoblast transplantation has been found capable of transiently delivering dystrophin and improving the strength of the injected dystrophic muscle, this approach has been hindered by the immune rejection problems as well as the poor survival and limited spread of the injected cells. In the present study, we have investigated whether the careful selection of donor myoblasts and host muscle for the myosin heavy chain expression (MyHCs) plays a role in the success of myoblast transfer. Highly purified normal myoblasts derived from the m. soleus and m. gastrocnemius white of normal mice were transplanted into the m. soleus (containing 70% of type I fibers) and gastrocnemius white (100% of type II fibers) of dystrophin deficient mdx mice. At several time-points after injection (10, 20 and 30 days), the number of dystrophin-positive fibers was monitored and compared among the different groups. A significantly higher number and better persistence of dystrophin-positive myofibers were observed when the injected muscle and donor myoblasts expressed a similar MyHC in comparison with myoblast transfer between host muscle and donor myoblasts that were not matched for MyHC. These results suggest that careful matching between the injected myoblasts and injected muscle for the MyHC expression can improve the efficiency of myoblast-mediated gene transfer to skeletal muscle. Gene Therapy (2000) 7, 428-437.
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Affiliation(s)
- Z Qu
- Growth and Development Laboratory, Department of Orthopaedic Surgery and Molecular Genetics and Biochemistry, Musculoskeletal Research Center, Children's Hospital of Pittsburgh and University of Pittsburgh, Pittsburgh, PA 15261, USA
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18
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Deconinck N, Rafael JA, Beckers-Bleukx G, Kahn D, Deconinck AE, Davies KE, Gillis JM. Consequences of the combined deficiency in dystrophin and utrophin on the mechanical properties and myosin composition of some limb and respiratory muscles of the mouse. Neuromuscul Disord 1998; 8:362-70. [PMID: 9713852 DOI: 10.1016/s0960-8966(98)00048-0] [Citation(s) in RCA: 65] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
The mechanical properties and the myosin isoform composition were studied in three isolated muscles (EDL, soleus, diaphragm) of mutant mice lacking both dystrophin and utrophin (dko). They were compared with the corresponding muscles of the normal and the dystrophin-deficient (mdx) and the utrophin-deficient (uko) mice. In comparison with mdx muscles, dko muscles show a significant reduction of the normalized isometric force, confirmed by the reduced muscular activity of the whole animal. Kinetics parameters (twitch time-to-peak and half-relaxation time) were slightly reduced, and the maximal speed of shortening of soleus, Vmax, was reduced by 30%. The maximal power output (muW/mm3) was reduced by 50% in dko soleus. In the three muscles studied, the relative myosin heavy chains (MHC) composition showed a shift towards slower isoforms. dko EDL presented a dramatic decrease of the resistance ot tetanic contraction with forced lengthenings (eccentric contractions), while muscle lacking only utrophin (uko mutants) display a normal resistance to this exacting mechanical challenge. These experiments suggest that lack of both dystrophin and utrophin is very detrimental to the mice and that mechanical properties of the muscles may explain the overall phenotype. Moreover these results bring some support to the idea that the expression of utrophin in mdx muscle compensates, to some extent, for the lack of dystrophin.
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Affiliation(s)
- N Deconinck
- Department de Physiologie, Université Catholique de Louvain, Bruxelles, Belgium.
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19
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Schaub MC, Hefti MA, Zuellig RA, Morano I. Modulation of contractility in human cardiac hypertrophy by myosin essential light chain isoforms. Cardiovasc Res 1998; 37:381-404. [PMID: 9614495 DOI: 10.1016/s0008-6363(97)00258-7] [Citation(s) in RCA: 96] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Cardiac hypertrophy is an adaptive response that normalizes wall stress and compensates for increased workload. It is accompanied by distinct qualitative and quantitative changes in the expression of protein isoforms concerning contractility, intracellular Ca(2+)-homeostasis and metabolism. Changes in the myosin subunit isoform expression improves contractility by an increase in force generation at a given Ca(2+)-concentration (increased Ca(2+)-sensitivity) and by improving the economy of the chemo-mechanical transduction process per amount of utilised ATP (increased duty ratio). In the human atrium this is achieved by partial replacement of the endogenous fast myosin by the ventricular slow-type heavy and light chains. In the hypertrophic human ventricle the slow-type beta-myosin heavy chains remain unchanged, but the ectopic expression of the atrial myosin essential light chain (ALC1) partially replaces the endogenous ventricular isoform (VLC1). The ventricular contractile apparatus with myosin containing ALC1 is characterised by faster cross-bridge kinetics, a higher Ca(2+)-sensitivity of force generation and an increased duty ratio. The mechanism for cross-bridge modulation relies on the extended Ala-Pro-rich N-terminus of the essential light chains of which the first eleven residues interact with the C-terminus of actin. A change in charge in this region between ALC1 and VLC1 explains their functional difference. The intracellular Ca(2+)-handling may be impaired in heart failure, resulting in either higher or lower cytosolic Ca(2+)-levels. Thus the state of the cardiomyocyte determines whether this hypertrophic adaptation remains beneficial or becomes detrimental during failure. Also discussed are the effects on contractility of long-term changes in isoform expression of other sarcomeric proteins. Positive and negative modulation of contractility by short-term phosphorylation reactions at multiple sites in the myosin regulatory light chain, troponin-I, troponin-T, alpha-tropomyosin and myosin binding protein-C are considered in detail.
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Affiliation(s)
- M C Schaub
- Institute of Pharmacology, University of Zurich, Switzerland.
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20
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Bruton JD, Wretman C, Katz A, Westerblad H. Increased tetanic force and reduced myoplasmic [P(i)] following a brief series of tetani in mouse soleus muscle. THE AMERICAN JOURNAL OF PHYSIOLOGY 1997; 272:C870-4. [PMID: 9124522 DOI: 10.1152/ajpcell.1997.272.3.c870] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Muscle performance is improved after a brief period of exercise (warm-up). One factor that is known to strongly affect force production is the myoplasmic concentration of inorganic phosphate ([P(i)]). Improved performance after warm-up may therefore be due to a reduction of [P(i)]. Herein, we show that after a warm-up protocol (15 tetani at 2-s intervals), tetanic force is increased by approximately 6% (P < 0.05) and [P(i)] is almost halved (P < 0.05) in isolated mouse soleus muscle. A warm-up protocol with longer intervals (15 tetani at 5-s intervals) reduced tetanic force and did not alter [P(i)]. We conclude that a reduction of [P(i)] contributes to the force-potentiating effect of warm-up.
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Affiliation(s)
- J D Bruton
- Department of Physiology and Pharmacology, Karolinska Institute, Stockholm, Sweden
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21
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Maréchal G, Beckers-Bleukx G, Berquin A, Coulton G. Isoforms of myosin in growing muscles of ky (kyphoscoliotic) mice. EUROPEAN JOURNAL OF BIOCHEMISTRY 1996; 241:916-22. [PMID: 8944783 DOI: 10.1111/j.1432-1033.1996.00916.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Kyphoscoliotic (ky) mice are spontaneous mutants of the BDL strain whose postural muscles atrophy during post-natal growth, resulting in extensive kyphoscoliosis in adult animals. At 21 days of age, the seven muscles examined were already well differentiated into fast, slow and mixed type on the basis of the proportions of their native myosin isoforms or their subunits. During post-natal growth, from 21 to 120 days of age, the normal pattern of myosin maturation was essentially respected by the ky mutation: fast muscles became faster, slow muscles became slower and mixed muscles specialized in both directions. However, the post-natal increases of myosin heavy chain 2B and fast myosin light chain LC3f were depressed in ky muscles, whilst there was novel expression of slow myosin light chains, LC1s and LC2s in muscles which normally did not express them. Intermediate native myosin IM was absent in adult ky soleus, but it increased in adult ky tibialis anterior. We conclude that the ky mutation depresses the normal post-natal transition towards faster muscles and results in adult muscles whose myosin isoforms are generally shifted in a fast-to-slow direction.
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Affiliation(s)
- G Maréchal
- Départment de Physiologie, Faculté de Médecine, UCL 5540, Brussels, Belgium
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22
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Bordas J, Lowy J. Studies on the mechanism of force production in intact striated muscles. J Muscle Res Cell Motil 1994; 15:489-90. [PMID: 7806641 DOI: 10.1007/bf00122122] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
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23
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Asmussen G, Beckers-Bleukx G, Maréchal G. The force-velocity relation of the rabbit inferior oblique muscle; influence of temperature. Pflugers Arch 1994; 426:542-7. [PMID: 8052524 DOI: 10.1007/bf00378532] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
The contractile properties of the rabbit inferior oblique muscle (IO) were studied in vitro with direct stimulation at temperatures between 20 and 35 degrees C. Isovelocity releases were used to determine the force/velocity relation. Cooling the muscle from 35 degrees C to 20 degrees C increased contraction and half-relaxation times of single twitches with a temperature coefficient (Q10) of 0.4, but did not affect significantly the twitch tension. The tetanic tension increases with increasing temperature (Q10 = 1.32). Cooling decreased the maximum shortening velocity of the IO with a Q10 of 1.6 and the maximum mechanical power with a Q10 of 2.3. At 35 degrees C, the maximum speed of shortening of the muscle (19 +/- 2 muscle lengths/s, mean +/- SEM) corresponded to a maximum shortening velocity of the sarcomeres of 57 +/- 6 microns/s. This value is similar to data obtained for extraocular muscles (EOM) of smaller rodents (mice and rats). In comparison with mammalian limb muscles the isometric and force-velocity properties of mammalian EOM appear to be virtually independent of the size of the animal. Thus, IO is a fast-twitch muscle endowed with a maximum velocity of shortening higher than that of fast-twitch skeletal muscle, but using a tetanic mechanical power lower than that produced by slow-twitch muscle: the combination of these properties makes it ideally suited to move an ocular globe of low mass at high velocity.
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Affiliation(s)
- G Asmussen
- Carl-Ludwig-Institut für Physiologie, Universität Leipzig, Germany
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