Pattern of summation with fatigue and inhibition of calcium release in rat muscle

MacIntosh, Brian R.; Glumpak, Jennifer J.; MacNaughton, Meredith B.; Rassier, Dilson E.

doi:10.1002/mus.22073

Cited by 4 publications

(4 citation statements)

References 28 publications

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“…The model predictions suggest that the deficits in free Ca 2+ concentration and Ca 2+ sensitivity reported in the literature, despite dramatically reducing force at submaximal stimulation frequencies, are insufficient to appreciably lower maximum tetanic force (< 5%). Our findings are supported by experimental observations from studies of dantrolene exposure (Krarup 1981 ; Macintosh et al 2011 ) and low-frequency fatigue (Westerblad et al 1993 ; Chin and Allen 1996 ; Glass et al 2018 ; Olsson et al 2020 ). For example, dantrolene partially inhibits SR Ca 2+ release (Desmedt and Hainaut 1977 ), inducing moderate reductions in twitch force (27–53%) or shifting the force-frequency relationship rightward without appreciable, if any, tetanic force loss [0–6% (Krarup 1981 ; Macintosh et al 2011 )].…”

Section: Discussionsupporting

confidence: 86%

“…Our findings are supported by experimental observations from studies of dantrolene exposure (Krarup 1981 ; Macintosh et al 2011 ) and low-frequency fatigue (Westerblad et al 1993 ; Chin and Allen 1996 ; Glass et al 2018 ; Olsson et al 2020 ). For example, dantrolene partially inhibits SR Ca 2+ release (Desmedt and Hainaut 1977 ), inducing moderate reductions in twitch force (27–53%) or shifting the force-frequency relationship rightward without appreciable, if any, tetanic force loss [0–6% (Krarup 1981 ; Macintosh et al 2011 )].…”

Section: Discussionsupporting

confidence: 86%

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Understanding altered contractile properties in advanced age: insights from a systematic muscle modelling approach

Mayfield

Cronin

Lichtwark

2022

Biomech Model Mechanobiol

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Age-related alterations of skeletal muscle are numerous and present inconsistently, and the effect of their interaction on contractile performance can be nonintuitive. Hill-type muscle models predict muscle force according to well-characterised contractile phenomena. Coupled with simple, yet reasonably realistic activation dynamics, such models consist of parameters that are meaningfully linked to fundamental aspects of muscle excitation and contraction. We aimed to illustrate the utility of a muscle model for elucidating relevant mechanisms and predicting changes in output by simulating the individual and combined effects on isometric force of several known ageing-related adaptations. Simulating literature-informed reductions in free Ca2+ concentration and Ca2+ sensitivity generated predictions at odds qualitatively with the characteristic slowing of contraction speed. Conversely, incorporating slower Ca2+ removal or a fractional increase in type I fibre area emulated expected changes; the former was required to simulate slowing of the twitch measured experimentally. Slower Ca2+ removal more than compensated for force loss arising from a large reduction in Ca2+ sensitivity or moderate reduction in Ca2+ release, producing realistic age-related shifts in the force-frequency relationship. Consistent with empirical data, reductions in free Ca2+ concentration and Ca2+ sensitivity reduced maximum tetanic force only slightly, even when acting in concert, suggesting a modest contribution to lower specific force. Lower tendon stiffness and slower intrinsic shortening speed slowed and prolonged force development in a compliance-dependent manner without affecting force decay. This work demonstrates the advantages of muscle modelling for exploring sources of variation and identifying mechanisms underpinning the altered contractile properties of aged muscle.

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Section: Discussionsupporting

confidence: 86%

Section: Discussionsupporting

confidence: 86%

Understanding altered contractile properties in advanced age: insights from a systematic muscle modelling approach

Mayfield

Cronin

Lichtwark

2022

Biomech Model Mechanobiol

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“…Clenbuterol’s functional effects appear linked to intra-cellular Ca 2+ homoeostasis, especially the leakage of SR Ca 2+ ( 55 ) . The decline in SR Ca 2+ and slow SR Ca 2+ re-uptake, with the latter contributing to slowed isometric relaxation, are believed to underpin fatigue in both fast- and slow-twitch muscles under tetanic ( 56 ) or non-tetanic stimulation ( 57 , 58 ) . If FO were to prevent SR Ca 2+ leakage and promote SR Ca 2+ re-uptake, this could explain the fatigue resistance.…”

Section: Discussionmentioning

confidence: 99%

Muscle fatigue resistance in the rat hindlimbin vivofrom low dietary intakes of tuna fish oil that selectively increase phospholipidn-3 docosahexaenoic acid according to muscle fibre type

2015

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Dietary fish oil (FO) modulates muscle O 2 consumption and contractile function, predictive of effects on muscle fatigue. High doses unattainable through human diet and muscle stimulation parameters used engender uncertainty in their physiological relevance. We tested the hypothesis that nutritionally relevant FO doses can modulate membrane fatty acid composition and muscle fatigue. Male Sprague-Dawley rats were randomised to control (10 % olive oil (OO) by weight) or low or moderate FO diet (LowFO and ModFO) (HiDHA tuna fish oil) for 15 weeks (LowFO: 0·3 % FO, 9·7 % OO, 0·25 % energy as EPA + DHA; ModFO: 1·25 % FO, 8·75 % OO, 1·0 % energy as EPA + DHA). Hindlimb muscle function was assessed under anaesthesia in vivo using repetitive 5 s burst sciatic nerve stimulation (0·05 ms, 7-12 V, 5 Hz, 10 s duty cycle, 300 s). There were no dietary differences in maximum developed muscle force. Repetitive peak developed force fell to 50 % within 62 (SEM 10) s in controls and took longer to decline in FO-fed rats (LowFO 110 (SEM 15) s; ModFO 117 (SEM 14) s) (P < 0·05). Force within bursts was better sustained with FO and maximum rates of force development and relaxation declined more slowly. The FO-fed rats incorporated higher muscle phospholipid DHA-relative percentages than controls (P < 0·001). Incorporation of DHA was greater in the fast-twitch gastrocnemius (Control 9·3 (SEM 0·8) %, LowFO 19·9 (SEM 0·4), ModFO 24·3 (SEM 1·0)) than in the slow-twitch soleus muscle (Control 5·1 (SEM 0·2), LowFO 14·3 (SEM 0·7), ModFO 18·0 (SEM 1·4)) (P < 0·001), which was comparable with the myocardium, in line with muscle fibre characteristics. The LowFO and ModFO diets, emulating human dietary and therapeutic supplement intake, respectively, both elicited muscle membrane DHA enrichment and fatigue resistance, providing a foundation for translating these physiological effects to humans.

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“…Notably, bursts of more than 4 sine‐waves decrease muscle strength. Potential mechanisms of this type of fatigue comprise limited Ca 2+ stores, progressive failure of action potential generation, and propagation or downregulation of ryanodine receptors 10…”

Section: Discussionmentioning

confidence: 99%

Muscle force development after low‐frequency magnetic burst stimulation in dogs

et al. 2012

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Introduction: Magnetic stimulation allows for painless and non‐invasive extrinsic motor nerve stimulation. Despite several advantages, the limited coupling to the target reduces the application of magnetic pulses in rehabilitation. According to experience with electrical stimulation, magnetic bursts could remove this constraint. Methods: A novel burst stimulator was used to apply single and burst pulses to the femoral nerve in 10 adult dogs. A figure‐of‐eight coil was connected, and pulses were applied at 7.5 HZ. Contractions of the quadriceps muscle were measured via an angle force transducer. Results: Muscle forces were significantly higher upon burst stimulation than after single pulses. Four consecutive burst pulses proved most effective. Stimulation by more bursts resulted in fatigue. Conclusion: Burst stimulation is superior to standard magnetic single pulses, and 4 consecutive burst pulses proved most effective. Muscle Nerve, 2012

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Pattern of summation with fatigue and inhibition of calcium release in rat muscle

Abstract: Inhibition of Ca(2+) release alters summation, but repetitive stimulation leading to fatigue changes it more substantially.

Cited by 4 publications

References 28 publications

Understanding altered contractile properties in advanced age: insights from a systematic muscle modelling approach

Understanding altered contractile properties in advanced age: insights from a systematic muscle modelling approach

Muscle fatigue resistance in the rat hindlimbin vivofrom low dietary intakes of tuna fish oil that selectively increase phospholipidn-3 docosahexaenoic acid according to muscle fibre type

Muscle force development after low‐frequency magnetic burst stimulation in dogs

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