Modulation of motor unit activity in biceps brachii by neuromuscular electrical stimulation applied to the contralateral arm

Amiridis, Ioannis G.; Mani, Diba; Almuklass, Awad M.; Matkowski, Boris; Gould, Jeffrey R.; Enoka, Roger M.

doi:10.1152/japplphysiol.00031.2015

Cited by 10 publications

(6 citation statements)

References 31 publications

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“…The main result of our study is the acute effect of the specific activation of peripheral sensory pathways on motor unit activity. This is in line with previous studies showing that the stimulation of the biceps brachii acutely impacts motor unit activity of the same muscle on the contralateral side (15, 18), though our stimulation parameters (i.e., pulse width and frequency) were slightly different. The changes in motor unit activity are likely due to the generation of excitatory post-synaptic potentials at the spinal level, through several potential neural pathways.…”

Section: Discussionsupporting

confidence: 93%

“…Other studies have found that supplemented sensory feedback could also improve motor functions in patients with multiple sclerosis (16) or stroke (17). It is noteworthy that the effect of supplemented sensory feedback on motor unit firing activity was not uniform (18), likely due to non-homogeneous distribution of afferent inputs to motor neurons from the same pool (19) and a size effect of afferent inputs onto motor neuron firing activity (20). Whether this divergent modulation of motor neuron firing activity within the same pool impacts the motor unit firing activity, and as a consequence, the modulation of force remains unclear.…”

Section: Introductionmentioning

confidence: 99%

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Transcutaneous electrical nerve stimulation acutely impacts motor unit firing activity during isometric contractions

Avrillon

Hernandez-Pavon

Kurukuti

et al. 2022

Preprint

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A low intensity electrical current delivered transcutaneously at a high frequency over a muscle can acutely recruit motor units in a physiological order by activating peripheral sensory pathways. This method has been used in patients to reduce tremor or supplement motor function, leading to the development of therapies and products. We aimed to better understand how the stimulation of the median nerve, the contralateral first dorsal interosseus muscle (FDI), and the combination of these two paradigms impact the motor unit activity from the FDI muscle. We identified and tracked the same motor units across the conditions and compared the electromyographic amplitude, motor unit discharge rates, and the degree of correlation between fast and slow oscillations of motor unit discharge rates. We found that the stimulation of the FDI muscle can acutely increase the electromyographic amplitude of the homonymous muscle on the contralateral side (F = 20.4; p < 0.001) while the discharge rate of motor units did not differ between the control and the stimulation condition (F = 0.2; p = 0.806). We did not observe any significant effect of the stimulation on the ratio of pairs of motor units with a significant correlation, showing that the stimulation barely impacted the distribution of correlated inputs to the pool of motor units. We did not observe short-term effects of the stimulation once it was discontinued. Overall, these results showed that the specific stimulation of peripheral sensory pathways can acutely impact motor unit firing activity without disturbing the neural control of force.

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Section: Discussionsupporting

confidence: 93%

Section: Introductionmentioning

confidence: 99%

Transcutaneous electrical nerve stimulation acutely impacts motor unit firing activity during isometric contractions

Avrillon

Hernandez-Pavon

Kurukuti

et al. 2022

Preprint

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“…; Amiridis et al . ), regenerative and degenerative responses to muscle injury (Song et al . ), and changes in mechanomyography after exercise (McKay et al .…”

Section: Discussionmentioning

confidence: 99%

Enhanced skeletal muscle regrowth and remodelling in massaged and contralateral non‐massaged hindlimb

Miller

Hamilton

Majeed

et al. 2017

The Journal of Physiology

117

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Key pointsr Muscle fibre cross sectional area is enhanced with massage in the form of cyclic compressive loading during regrowth after atrophy.r Massage enhances protein synthesis of the myofibrillar and cytosolic, but not the mitochondrial fraction, in muscle during regrowth. r Massage in the form of cyclic compressive loading is a potential anabolic intervention during muscle regrowth after atrophy.Abstract Massage, in the form of cyclic compressive loading (CCL), is associated with multiple health benefits, but its potential anabolic effect on atrophied muscle has not been investigated. We hypothesized that the mechanical activity associated with CCL induces an anabolic effect in skeletal muscle undergoing regrowth after a period of atrophy. Fischer-Brown Norway rats at 10 months of age were hindlimb unloaded for a period of 2 weeks. The rats were then allowed reambulation with CCL applied at a 4.5 N load at 0.5 Hz frequency for 30 min every other day for four bouts during a regrowth period of 8 days. Muscle fibre cross sectional area was enhanced by 18% with massage during regrowth compared to reloading alone, and this was accompanied by elevated myofibrillar and cytosolic protein as well as DNA synthesis. Focal adhesion kinase phosphorylation indicated that CCL increased mechanical stimulation, while a higher number of Pax7 + cells likely explains the elevated DNA synthesis. Surprisingly, the contralateral non-massaged limb exhibited a comparable 17% higher muscle fibre size compared to reloading alone, and myofibrillar protein synthesis, but not DNA synthesis, was also elevated. We conclude that massage in the form of CCL induces an anabolic response in muscles regrowing after an atrophy-inducing event. We suggest that massage can be used as an intervention to aid in the regrowth of muscle lost during immobilization.

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“…Unilateral models of denervation are widely used for studies investigating the pathophysiology of muscle atrophy. However, there is a growing evidence for crossover effects of exercise, electrical stimulation, inflammation and injury in contralateral muscle 14,35,36 . Although many previous studies have shown denervation‐induced alterations in proteostatic properties, most of them were using contralateral‐innervated muscle of a mouse with a nerve transection as experimental control 37,38 .…”

Section: Discussionmentioning

confidence: 99%

Determining the contributions of protein synthesis and breakdown to muscle atrophy requires non‐steady‐state equations

Kobak

Lawrence

Pharaoh

et al. 2021

J cachexia sarcopenia muscle

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Background Ageing and cachexia cause a loss of muscle mass over time, indicating that protein breakdown exceeds protein synthesis. Deuterium oxide (D2O) is used for studies of protein turnover because of the advantages of long‐term labelling, but these methods introduce considerations that have been largely overlooked when studying conditions of protein gain or loss. The purpose of this study was to demonstrate the importance of accounting for a change in protein mass, a non‐steady state, during D2O labelling studies while also exploring the contribution of protein synthesis and breakdown to denervation‐induced muscle atrophy. Methods Adult (6 months) male C57BL/6 mice (n = 14) were labelled with D2O for a total of 7 days following unilateral sciatic nerve transection to induce denervation of hindlimb muscles. The contralateral sham limb and nonsurgical mice (n = 5) were used as two different controls to account for potential crossover effects of denervation. We calculated gastrocnemius myofibrillar and collagen protein synthesis and breakdown assuming steady‐state or using non‐steady‐state modelling. We measured RNA synthesis rates to further understand ribosomal turnover during atrophy. Results Gastrocnemius mass was less in denervated muscle (137 ± 9 mg) compared with sham (174 ± 15 mg; P < 0.0001) or nonsurgical control (162 ± 5 mg; P < 0.0001). With steady‐state calculations, fractional synthesis and breakdown rates (FSR and FBR) were lower in the denervated muscle (1.49 ± 0.06%/day) compared with sham (1.81 ± 0.09%/day; P < 0.0001) or nonsurgical control (2.27 ± 0.04%/day; P < 0.0001). When adjusting for change in protein mass, FSR was 4.21 ± 0.19%/day in denervated limb, whereas FBR was 4.09 ± 0.22%/day. When considering change in protein mass (ksyn), myofibrillar synthesis was lower in denervated limb (2.44 ± 0.14 mg/day) compared with sham (3.43 ± 0.22 mg/day; P < 0.0001) and non‐surgical control (3.74 ± 0.12 mg/day; P < 0.0001), whereas rate of protein breakdown (kdeg, 1/t) was greater in denervated limb (0.050 ± 0.003) compared with sham (0.019 ± 0.001; P < 0.0001) and nonsurgical control (0.023 ± 0.000; P < 0.0001). Muscle collagen breakdown was completely inhibited during denervation. There was a strong correlation (r = 0.83, P < 0.001) between RNA and myofibrillar protein synthesis in sham but not denervated muscle. Conclusions We show conflicting results between steady‐ and non‐steady‐state calculations on myofibrillar protein synthesis and breakdown during periods of muscle loss. We also found that collagen accumulation was largely from a decrease in collagen breakdown. Comparison between sham and non‐surgical control demonstrated a crossover effect of denervation on myofibrillar protein synthesis and ribosomal biogenesis, which impacts study design for unilateral atrophy studies. These considerations are important because not accounting for them can mislead therapeutic attempts to maintain muscle mass.

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Modulation of motor unit activity in biceps brachii by neuromuscular electrical stimulation applied to the contralateral arm

Cited by 10 publications

References 31 publications

Transcutaneous electrical nerve stimulation acutely impacts motor unit firing activity during isometric contractions

Transcutaneous electrical nerve stimulation acutely impacts motor unit firing activity during isometric contractions

Enhanced skeletal muscle regrowth and remodelling in massaged and contralateral non‐massaged hindlimb

Determining the contributions of protein synthesis and breakdown to muscle atrophy requires non‐steady‐state equations

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