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Pflugers Archiv : European Journal of... Mar 202214-3-3 proteins (14-3-3 s) are a family of highly conserved proteins that regulate many cellular processes in eukaryotes by interacting with a diverse array of client... (Review)
Review
14-3-3 proteins (14-3-3 s) are a family of highly conserved proteins that regulate many cellular processes in eukaryotes by interacting with a diverse array of client proteins. The 14-3-3 proteins have been implicated in several disease states and previous reviews have condensed the literature with respect to their structure, function, and the regulation of different cellular processes. This review focuses on the growing body of literature exploring the important role 14-3-3 proteins appear to play in regulating the biochemical and biophysical events associated with excitation-contraction coupling (ECC) in muscle. It presents both a timely and unique analysis that seeks to unite studies emphasizing the identification and diversity of 14-3-3 protein function and client protein interactions, as modulators of muscle contraction. It also highlights ideas within these two well-established but intersecting fields that support further investigation with respect to the mechanistic actions of 14-3-3 proteins in the modulation of force generation in muscle.
Topics: 14-3-3 Proteins; Calcium; Excitation Contraction Coupling; Humans; Muscle Contraction; Muscle, Skeletal
PubMed: 34820713
DOI: 10.1007/s00424-021-02635-x -
Biomechanics and Modeling in... Feb 2023A FLIP device gives cross-sectional area along the length of the esophagus and one pressure measurement, both as a function of time. Deducing mechanical properties of...
A FLIP device gives cross-sectional area along the length of the esophagus and one pressure measurement, both as a function of time. Deducing mechanical properties of the esophagus including wall material properties, contraction strength, and wall relaxation from these data are a challenging inverse problem. Knowing mechanical properties can change how clinical decisions are made because of its potential for in-vivo mechanistic insights. To obtain such information, we conducted a parametric study to identify peristaltic regimes by using a 1D model of peristaltic flow through an elastic tube closed on both ends and also applied it to interpret clinical data. The results gave insightful information about the effect of tube stiffness, fluid/bolus density and contraction strength on the resulting esophagus shape through quantitive representations of the peristaltic regimes. Our analysis also revealed the mechanics of the opening of the contraction area as a function of bolus flow resistance. Lastly, we concluded that peristaltic driven flow displays three modes of peristaltic geometries, but all physiologically relevant flows fall into two peristaltic regimes characterized by a tight contraction.
Topics: Deglutition; Muscle Contraction; Esophagus; Peristalsis; Body Fluids
PubMed: 36352039
DOI: 10.1007/s10237-022-01625-x -
Sensors (Basel, Switzerland) Mar 2022Complications related to neuromuscular blockade (NMB) could occur during anesthesia induction, maintenance, and emergency. It is recommended that neuromuscular... (Review)
Review
Complications related to neuromuscular blockade (NMB) could occur during anesthesia induction, maintenance, and emergency. It is recommended that neuromuscular monitoring techniques be utilized perioperatively to avoid adverse outcomes. However, current neuromuscular monitoring methods possess different shortcomings. They are cumbersome to use, susceptible to disturbances, and have limited alternative monitoring sites. Phonomyography (PMG) monitoring based on the acoustic signals yielded by skeletal muscle contraction is emerging as an interesting and innovative method. This technique is characterized by its convenience, stable signal quality, and multimuscle recording ability and shows great potential in the application field. This review summarizes the progression of PMG on perioperative neuromuscular monitoring chronologically and presents the merits, demerits, and challenges of PMG-based equipment, aiming at underscoring the potential of PMG-based apparatuses for neuromuscular monitoring.
Topics: Electric Stimulation; Muscle Contraction; Myography; Neuromuscular Blockade; Neuromuscular Monitoring
PubMed: 35408063
DOI: 10.3390/s22072448 -
The FEBS Journal Mar 2022From the discovery of ATP and motor proteins to synaptic neurotransmitters and growth factor control of cell differentiation, skeletal muscle has provided an extreme... (Review)
Review
From the discovery of ATP and motor proteins to synaptic neurotransmitters and growth factor control of cell differentiation, skeletal muscle has provided an extreme model system in which to understand aspects of tissue function. Muscle is one of the few tissues that can undergo both increase and decrease in size during everyday life. Muscle size depends on its contractile activity, but the precise cellular and molecular pathway(s) by which the activity stimulus influences muscle size and strength remain unclear. Four correlates of muscle contraction could, in theory, regulate muscle growth: nerve-derived signals, cytoplasmic calcium dynamics, the rate of ATP consumption and physical force. Here, we summarise the evidence for and against each stimulus and what is known or remains unclear concerning their molecular signal transduction pathways and cellular effects. Skeletal muscle can grow in three ways, by generation of new syncytial fibres, addition of nuclei from muscle stem cells to existing fibres or increase in cytoplasmic volume/nucleus. Evidence suggests the latter two processes contribute to exercise-induced growth. Fibre growth requires increase in sarcolemmal surface area and cytoplasmic volume at different rates. It has long been known that high-force exercise is a particularly effective growth stimulus, but how this stimulus is sensed and drives coordinated growth that is appropriately scaled across organelles remains a mystery.
Topics: Adenosine Triphosphate; Exercise; Muscle Contraction; Muscle Fibers, Skeletal; Muscle, Skeletal; Myosins
PubMed: 33755332
DOI: 10.1111/febs.15820 -
Scandinavian Journal of Medicine &... Oct 2022During voluntary muscle contractions, force output is characterized by constant inherent fluctuations, which can be quantified either according to their magnitude or... (Review)
Review
During voluntary muscle contractions, force output is characterized by constant inherent fluctuations, which can be quantified either according to their magnitude or temporal structure, that is, complexity. The presence of such fluctuations when targeting a set force indicates that control of force is not perfectly accurate, which can have significant implications for task performance. Compared to young adults, older adults demonstrate a greater magnitude and lower complexity in force fluctuations, indicative of decreased steadiness, and adaptability of force output, respectively. The nature of this loss-of-force control depends not only on the age of the individual but also on the muscle group performing the task, the intensity and type of contraction and whether the task is performed with additional cognitive load. Importantly, this age-associated loss-of-force control is correlated with decreased performance in a range of activities of daily living and is speculated to be of greater importance for functional capacity than age-associated decreases in maximal strength. Fortunately, there is evidence that acute physical activity interventions can reverse the loss-of-force control in older individuals, though whether this translates to improved functional performance and whether lifelong physical activity can protect against the changes have yet to be established. A number of mechanisms, related to both motor unit properties and the behavior of motor unit populations, have been proposed for the age-associated changes in force fluctuations. It is likely, though, that age-associated changes in force control are related to increased common fluctuations in the discharge times of motor units.
Topics: Activities of Daily Living; Aged; Aging; Electromyography; Exercise; Humans; Isometric Contraction; Muscle Contraction; Muscle, Skeletal; Young Adult
PubMed: 35815914
DOI: 10.1111/sms.14207 -
Sensors (Basel, Switzerland) Jun 2022Muscle co-contraction plays a significant role in motion control. Available detection methods typically only provide information in the time domain. The current...
BACKGROUND
Muscle co-contraction plays a significant role in motion control. Available detection methods typically only provide information in the time domain. The current investigation proposed a novel approach for muscle co-contraction detection in the time-frequency domain, based on continuous wavelet transform (CWT).
METHODS
In the current study, the CWT-based cross-energy localization of two surface electromyographic (sEMG) signals in the time-frequency domain, i.e., the CWT coscalogram, was adopted for the first time to characterize muscular co-contraction activity. A CWT-based denoising procedure was applied for removing noise from the sEMG signals. Algorithm performances were checked on synthetic and real sEMG signals, stratified for signal-to-noise ratio (SNR), and then validated against an approach based on the acknowledged double-threshold statistical algorithm (DT).
RESULTS
The CWT approach provided an accurate prediction of co-contraction timing in simulated and real datasets, minimally affected by SNR variability. The novel contribution consisted of providing the frequency values of each muscle co-contraction detected in the time domain, allowing us to reveal a wide variability in the frequency content between subjects and within stride.
CONCLUSIONS
The CWT approach represents a relevant improvement over state-of-the-art approaches that provide only a numerical co-contraction index or, at best, dynamic information in the time domain. The robustness of the methodology and the physiological reliability of the experimental results support the suitability of this approach for clinical applications.
Topics: Algorithms; Electromyography; Humans; Muscle Contraction; Muscle, Skeletal; Reproducibility of Results; Signal Processing, Computer-Assisted; Wavelet Analysis
PubMed: 35808382
DOI: 10.3390/s22134886 -
European Journal of Applied Physiology Oct 2022Declines in muscle force, power, and contractile function can be observed in older adults, clinical populations, inactive individuals, and injured athletes. Passive... (Review)
Review
Declines in muscle force, power, and contractile function can be observed in older adults, clinical populations, inactive individuals, and injured athletes. Passive heating exposure (e.g., hot baths, sauna, or heated garments) has been used for health purposes, including skeletal muscle treatment. An acute increase in muscle temperature by passive heating can increase the voluntary rate of force development and electrically evoked contraction properties (i.e., time to peak twitch torque, half-relation time, and electromechanical delay). The improvements in the rate of force development and evoked contraction assessments with increased muscle temperature after passive heating reveal peripheral mechanisms' potential role in enhancing muscle contraction. This review aimed to summarise, discuss, and highlight the potential role of an acute passive heating stimulus on skeletal muscle cells to improve contractile function. These mechanisms include increased calcium kinetics (release/reuptake), calcium sensitivity, and increased intramuscular fluid.
Topics: Aged; Calcium; Humans; Isometric Contraction; Muscle Contraction; Muscle, Skeletal; Temperature; Torque
PubMed: 35771296
DOI: 10.1007/s00421-022-04991-7 -
Journal of Electromyography and... Jun 2023The mathematical muscle models should include several aspects of muscle structure and physiology. First, muscle force is the sum of forces of multiple motor units (MUs),... (Review)
Review
The mathematical muscle models should include several aspects of muscle structure and physiology. First, muscle force is the sum of forces of multiple motor units (MUs), which have different contractile properties and play different roles in generating muscle force. Second, whole muscle activity is an effect of net excitatory inputs to a pool of motoneurons innervating the muscle, which have different excitability, influencing MU recruitment. In this review, we compare various methods for modeling MU twitch and tetanic forces and then discuss muscle models composed of different MU types and number. We first present four different analytical functions used for twitch modeling and show limitations related to the number of twitch describing parameters. We also show that a nonlinear summation of twitches should be considered in modeling tetanic contractions. We then compare different muscle models, most of which are variations of Fuglevand's model, adopting a common drive hypothesis and the size principle. We pay attention to integrating previously developed models into a consensus model based on physiological data from in vivo experiments on the rat medial gastrocnemius muscle and its respective motoneurons. Finally, we discuss the shortcomings of existing models and potential applications for studying MU synchronization, potentiation, and fatigue.
Topics: Rats; Animals; Muscle, Skeletal; Muscle Contraction; Motor Neurons; Electric Stimulation
PubMed: 37099899
DOI: 10.1016/j.jelekin.2023.102774 -
Journal of Biomechanics Jul 2023Muscle energetics encompasses the relationships between mechanical performance and the biochemical and thermal changes that occur during muscular activity. The... (Review)
Review
Muscle energetics encompasses the relationships between mechanical performance and the biochemical and thermal changes that occur during muscular activity. The biochemical reactions that underpin contraction are described and the way in which these are manifest in experimental recordings, as initial and recovery heat, is illustrated. Energy use during contraction can be partitioned into that related to cross-bridge force generation and that associated with activation by Ca. Activation processes account for 25-45% of ATP turnover in an isometric contraction, varying amongst muscles. Muscle energy use during contraction depends on the nature of the contraction. When shortening muscles produce less force than when contracting isometrically but use energy at a greater rate. These characteristics reflect more rapid cross-bridge cycling when shortening. When lengthening, muscles produce more force than in an isometric contraction but use energy at a lower rate. In that case, cross-bridges cycle but via a pathway in which ATP splitting is not completed. Shortening muscles convert part of the free energy available from ATP hydrolysis into work with the remainder appearing as heat. In the most efficient muscle studied, that of a tortoise, cross-bridges convert a maximum of 47% of the available energy into work. In most other muscles, only 20-30% of the free energy from ATP hydrolysis is converted into work.
Topics: Energy Metabolism; Adenosine Triphosphate; Muscle Contraction; Muscles; Isometric Contraction
PubMed: 37302165
DOI: 10.1016/j.jbiomech.2023.111669 -
Pflugers Archiv : European Journal of... Dec 2023Cell contraction plays an important role in many physiological and pathophysiological processes. This includes functions in skeletal, heart, and smooth muscle cells,... (Review)
Review
Cell contraction plays an important role in many physiological and pathophysiological processes. This includes functions in skeletal, heart, and smooth muscle cells, which lead to highly coordinated contractions of multicellular assemblies, and functions in non-muscle cells, which are often highly localized in subcellular regions and transient in time. While the regulatory processes that control cell contraction in muscle cells are well understood, much less is known about cell contraction in non-muscle cells. In this review, we focus on the mechanisms that control cell contraction in space and time in non-muscle cells, and how they can be investigated by light-based methods. The review particularly focusses on signal networks and cytoskeletal components that together control subcellular contraction patterns to perform functions on the level of cells and tissues, such as directional migration and multicellular rearrangements during development. Key features of light-based methods that enable highly local and fast perturbations are highlighted, and how experimental strategies can capitalize on these features to uncover causal relationships in the complex signal networks that control cell contraction.
Topics: Muscle, Smooth; Muscle Contraction; Myocytes, Smooth Muscle; Phosphorylation
PubMed: 37851146
DOI: 10.1007/s00424-023-02864-2