scholarly journals Chronic clenbuterol treatment compromises force production without directly altering skeletal muscle contractile machinery

2015 ◽  
Vol 593 (8) ◽  
pp. 2071-2084 ◽  
Author(s):  
G. Py ◽  
C. Ramonatxo ◽  
P. Sirvent ◽  
A. M. J. Sanchez ◽  
A. G. Philippe ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Force Production ◽  
Chronic Clenbuterol ◽  
Muscle Contractile

scholarly journals Transverse tubule remodeling enhances Orai1-dependent Ca2+ entry in skeletal muscle

eLife ◽  
2019 ◽  
Vol 8 ◽  
Author(s):  
Antonio Michelucci ◽  
Simona Boncompagni ◽  
Laura Pietrangelo ◽  
Maricela García-Castañeda ◽  
Takahiro Takano ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Time Course ◽  
Acute Exercise ◽  
Muscle Force ◽  
Contractile Function ◽  
Force Production ◽  
High Frequency Stimulation ◽  
Frequency Stimulation ◽  
Muscle Force Production ◽  
Muscle Contractile

Exercise promotes the formation of intracellular junctions in skeletal muscle between stacks of sarcoplasmic reticulum (SR) cisternae and extensions of transverse-tubules (TT) that increase co-localization of proteins required for store-operated Ca2+ entry (SOCE). Here, we report that SOCE, peak Ca2+ transient amplitude and muscle force production during repetitive stimulation are increased after exercise in parallel with the time course of TT association with SR-stacks. Unexpectedly, exercise also activated constitutive Ca2+ entry coincident with a modest decrease in total releasable Ca2+ store content. Importantly, this decrease in releasable Ca2+ store content observed after exercise was reversed by repetitive high-frequency stimulation, consistent with enhanced SOCE. The functional benefits of exercise on SOCE, constitutive Ca2+ entry and muscle force production were lost in mice with muscle-specific loss of Orai1 function. These results indicate that TT association with SR-stacks enhances Orai1-dependent SOCE to optimize Ca2+ dynamics and muscle contractile function during acute exercise.

Functional aspects of skeletal muscle contractile apparatus and sarcoplasmic reticulum after fatigue

1998 ◽  
Vol 85 (2) ◽  
pp. 619-626 ◽  
Author(s):  
Jay H. Williams ◽  
Christopher W. Ward ◽  
Espen E. Spangenburg ◽  
Reagan M. Nelson
Keyword(s):  
Skeletal Muscle ◽  
Sarcoplasmic Reticulum ◽  
Atpase Activity ◽  
Force Production ◽  
Contractile Apparatus ◽  
Actomyosin Atpase ◽  
Functional Aspects ◽  
Intact Muscle ◽  
Cross Bridges ◽  
Muscle Contractile

This study examined the effects of fatigue on the functional aspects of the contractile apparatus and sarcoplasmic reticulum (SR). Frog semitendinosus muscles were stimulated to fatigue, and skinned fibers or a homogenate fraction was prepared from both fatigued and rested contralateral muscles. In fatigued fibers, maximal Ca2+-activated force of the contractile apparatus was unaltered, whereas maximal actomyosin-ATPase activity was depressed by 20%. The Ca2+ sensitivity of force was increased, whereas that of actomyosin-ATPase was not altered. Also, the rate constant for tension redevelopment was decreased at submaximal Ca2+ concentration. These latter findings suggest that fatigue slows the dissociation of force-generating myosin cross bridges. Ca2+ uptake and Ca2+-ATPase activity of the SR were depressed by 46 and 21%, respectively, in the fatigued muscles. Fatigue also reduced the rates of SR Ca2+ release evoked by AgNO3 and 4-chloro- m-cresol by 38 and 45%, respectively. During fatigue, the contractile apparatus and SR undergo intrinsic functional alterations. These changes likely result in altered force production and energy consumption by the intact muscle.

scholarly journals Effects of vitamin E and α-lipoic acid on skeletal muscle contractile properties

2001 ◽  
Vol 90 (4) ◽  
pp. 1424-1430 ◽  
Author(s):  
Jeff S. Coombes ◽  
Scott K. Powers ◽  
Benjamin Rowell ◽  
Karyn L. Hamilton ◽  
Stephen L. Dodd ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Vitamin E ◽  
Lipoic Acid ◽  
Force Production ◽  
Contractile Properties ◽  
Diaphragm Muscle ◽  
Reduced Form ◽  
Muscle Contractile Properties ◽  
Fatigue Protocol ◽  
Muscle Contractile

Initial experiments were conducted using an in situ rat tibialis anterior (TA) muscle preparation to assess the influence of dietary antioxidants on muscle contractile properties. Adult Sprague-Dawley rats were divided into two dietary groups: 1) control diet (Con) and 2) supplemented with vitamin E (VE) and α-lipoic acid (α-LA) (Antiox). Antiox rats were fed the Con rats' diet (AIN-93M) with an additional 10,000 IU VE/kg diet and 1.65 g/kg α-LA. After an 8-wk feeding period, no differences existed ( P > 0.05) between the two dietary groups in maximum specific tension before or after a fatigue protocol or in force production during the fatigue protocol. However, in unfatigued muscle, maximal twitch tension and tetanic force production at stimulation frequencies ≤40 Hz were less ( P < 0.05) in Antiox animals compared with Con. To investigate which antioxidant was responsible for the depressed force production, a second experiment was conducted using an in vitro rat diaphragm preparation. Varying concentrations of VE and dihydrolipoic acid, the reduced form of α-LA, were added either individually or in combination to baths containing diaphragm muscle strips. The results from these experiments indicate that high levels of VE depress skeletal muscle force production at low stimulation frequencies.

scholarly journals Activation of the dopamine 1 and dopamine 5 receptors increase skeletal muscle mass and force production under non-atrophying and atrophying conditions

2011 ◽  
Vol 12 (1) ◽  
Author(s):  
Deborah L Reichart ◽  
Richard T Hinkle ◽  
Frank R Lefever ◽  
Elizabeth T Dolan ◽  
Jeffrey A Dietrich ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Muscle Mass ◽  
Skeletal Muscle Mass ◽  
Force Production

Dantrolene Sodium: Effects on Crustacean Muscle

1974 ◽  
Vol 52 (4) ◽  
pp. 887-890 ◽  
Author(s):  
L. L. Odette ◽  
H. L. Atwood
Keyword(s):  
Skeletal Muscle ◽  
Electrical Properties ◽  
Neuromuscular Transmission ◽  
Contractile Response ◽  
Callinectes Sapidus ◽  
Muscle Membrane ◽  
Dantrolene Sodium ◽  
Muscle Contractile ◽  
Indirect Stimulation ◽  
Vertebrate Skeletal Muscle

The effect of dantrolene sodium, a muscle relaxant effective on vertebrate skeletal muscle, has been studied on the stretcher muscle of a crab (Callinectes sapidus). The drug rapidly and reversibly attenuates the muscle contractile response to direct and indirect stimulation. Neuromuscular transmission is unaffected, as are the electrical properties of the muscle membrane. It is concluded that dantrolene sodium uncouples excitation–contraction mechanisms in crustacean tonic muscle.

scholarly journals Dysfunction of muscle contraction with impaired intracellular Ca2+ handling in skeletal muscle and the effect of exercise training in male db/db mice

2019 ◽  
Vol 126 (1) ◽  
pp. 170-182 ◽  
Author(s):  
Hiroaki Eshima ◽  
Yoshifumi Tamura ◽  
Saori Kakehi ◽  
Kyoko Nakamura ◽  
Nagomi Kurebayashi ◽  
...  
Keyword(s):  
Type 2 Diabetes ◽  
Skeletal Muscle ◽  
Exercise Training ◽  
Muscle Contraction ◽  
Contractile Function ◽  
Contractile Force ◽  
Contractile Dysfunction ◽  
Muscle Contractile ◽  
Type 2 Diabetic

Type 2 diabetes is characterized by reduced contractile force production and increased fatigability of skeletal muscle. While the maintenance of Ca2+ homeostasis during muscle contraction is a requisite for optimal contractile function, the mechanisms underlying muscle contractile dysfunction in type 2 diabetes are unclear. Here, we investigated skeletal muscle contractile force and Ca2+ flux during contraction and pharmacological stimulation in type 2 diabetic model mice ( db/db mice). Furthermore, we investigated the effect of treadmill exercise training on muscle contractile function. In male db/db mice, muscle contractile force and peak Ca2+ levels were both lower during tetanic stimulation of the fast-twitch muscles, while Ca2+ accumulation was higher after stimulation compared with control mice. While 6 wk of exercise training did not improve glucose tolerance, exercise did improve muscle contractile dysfunction, peak Ca2+ levels, and Ca2+ accumulation following stimulation in male db/db mice. These data suggest that dysfunctional Ca2+ flux may contribute to skeletal muscle contractile dysfunction in type 2 diabetes and that exercise training may be a promising therapeutic approach for dysfunctional skeletal muscle contraction. NEW & NOTEWORTHY The purpose of this study was to examine muscle contractile function and Ca2+ regulation as well as the effect of exercise training in skeletal muscle in obese diabetic mice ( db/db). We observed impairment of muscle contractile force and Ca2+ regulation in a male type 2 diabetic animal model. These dysfunctions in muscle were improved by 6 wk of exercise training.

scholarly journals Alterations in skeletal muscle contractile force following acute exposure to thromboxane A2.

2009 ◽  
Vol 23 (S1) ◽  
Author(s):  
Chad D. Touchberry ◽  
Jessica K. Stone ◽  
Leticia S. Brotto ◽  
Marco P. Brotto ◽  
Michael J. Wacker
Keyword(s):  
Skeletal Muscle ◽  
Thromboxane A2 ◽  
Contractile Force ◽  
Acute Exposure ◽  
Muscle Contractile
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