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Advances in Physiology Education Dec 2003This brief review serves as a refresher on smooth muscle physiology for those educators who teach in medical and graduate courses of physiology. Additionally, those... (Review)
Review
This brief review serves as a refresher on smooth muscle physiology for those educators who teach in medical and graduate courses of physiology. Additionally, those professionals who are in need of an update on smooth muscle physiology may find this review to be useful. Smooth muscle lacks the striations characteristic of cardiac and skeletal muscle. Layers of smooth muscle cells line the walls of various organs and tubes in the body, and the contractile function of smooth muscle is not under voluntary control. Contractile activity in smooth muscle is initiated by a Ca(2+)-calmodulin interaction to stimulate phosphorylation of the light chain of myosin. Ca(2+) sensitization of the contractile proteins is signaled by the RhoA/Rho kinase pathway to inhibit the dephosphorylation of the light chain by myosin phosphatase, thereby maintaining force generation. Removal of Ca(2+) from the cytosol and stimulation of myosin phosphatase initiate the process of smooth muscle relaxation.
Topics: Calcium; Humans; Muscle Contraction; Muscle Relaxation; Muscle, Smooth
PubMed: 14627618
DOI: 10.1152/advan.00025.2003 -
The Journal of General Physiology Sep 2022
Topics: Calcium; Excitation Contraction Coupling; Heart; Muscle Contraction; Muscle, Skeletal; Muscle, Smooth
PubMed: 35984377
DOI: 10.1085/jgp.202213244 -
Physiology (Bethesda, Md.) Nov 2019Muscle contraction is a three-dimensional process, as anyone who has observed a bulging muscle knows. Recent studies suggest that the three-dimensional nature of muscle... (Review)
Review
Muscle contraction is a three-dimensional process, as anyone who has observed a bulging muscle knows. Recent studies suggest that the three-dimensional nature of muscle contraction influences its mechanical output. Shape changes and radial forces appear to be important across scales of organization. Muscle architectural gearing is an emerging example of this process.
Topics: Animals; Biomechanical Phenomena; Humans; Muscle Contraction; Muscle, Skeletal
PubMed: 31577172
DOI: 10.1152/physiol.00023.2019 -
BioMed Research International 2015
Topics: Humans; Muscle Contraction; Muscle, Skeletal; Myosins
PubMed: 25961034
DOI: 10.1155/2015/694345 -
Journal of Biomedicine & Biotechnology 2012
Topics: Animals; Cell Movement; Humans; Mice; Molecular Motor Proteins; Muscle Contraction; Myocardial Contraction
PubMed: 22500082
DOI: 10.1155/2012/257812 -
The Journal of Physiological Sciences :... Jan 2017Knowledge accumulated in the field of energetics of muscle contraction has been reviewed in this article. Active muscle converts chemical energy into heat and work.... (Review)
Review
Knowledge accumulated in the field of energetics of muscle contraction has been reviewed in this article. Active muscle converts chemical energy into heat and work. Therefore, measurements of heat production and mechanical work provide the framework for understanding the process of energy conversion in contraction. In the 1970s, precise comparison between energy output and the associated chemical reactions was performed. It has been found that the two do not match in several situations, resulting in an energy balance discrepancy. More recently, efforts in resolving these discrepancies in the energy balance have been made involving chemical analysis, phosphorus nuclear magnetic resonance spectroscopy, and microcalorimetry. Through reviewing the evidence from these studies, the energy balance discrepancy developed early during isometric contraction has become well understood on a quantitative basis. In this situation energy balance is established when we take into account the binding of Ca to sarcoplasmic proteins such as troponin and parvalbumin, and also the shift of cross-bridge states. On the other hand, the energy balance discrepancy observed during rapid shortening still remains to be clarified. The problem may be related to the essential mechanism of cross-bridge action.
Topics: Actomyosin; Animals; Calorimetry; Energy Metabolism; Humans; Muscle Contraction; Muscle, Skeletal
PubMed: 27412384
DOI: 10.1007/s12576-016-0470-3 -
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 -
Neurogastroenterology and Motility May 2008Smooth muscle cells (SMC) make up the muscular portion of the gastrointestinal (GI) tract from the distal oesophagus to the internal anal sphincter. Coordinated... (Review)
Review
Smooth muscle cells (SMC) make up the muscular portion of the gastrointestinal (GI) tract from the distal oesophagus to the internal anal sphincter. Coordinated contractions of these cells produce the motor patterns of GI motility. Considerable progress was made during the last 20 years to understand the basic mechanisms controlling excitation-contraction (E-C) coupling. The smooth muscle motor is now understood in great molecular detail, and much has been learned about the mechanisms that deliver and recover Ca2+ during contractions. The majority of Ca2+ that initiates contractions comes from the external solution and is supplied by voltage-dependent Ca2+ channels (VDCC). VDCC are regulated largely by the effects of K+ and non-selective cation conductances (NSCC) on cell membrane potential and excitability. Ca2+ entry is supplemented by release of Ca2+ from IP(3) receptor-operated stores and by mechanisms that alter the sensitivity of the contractile apparatus to changes in cytoplasmic Ca2+. Molecular studies of the regulation of smooth muscle have been complicated by the plasticity of SMC and difficulties in culturing these cells without dramatic phenotypic changes. Major questions remain to be resolved regarding the details of E-C coupling in human GI smooth muscles. New discoveries regarding molecular expression that give GI smooth muscle their unique properties, the phenotypic changes that occur in SMC in GI motor disorders, tissue engineering approaches to repair or replace defective muscular regions, and molecular manipulations of GI smooth muscles in animals models and in cell culture will be topics for exciting investigations in the future.
Topics: Animals; Gastrointestinal Tract; Humans; Muscle Contraction; Muscle Relaxation; Muscle, Smooth
PubMed: 18402641
DOI: 10.1111/j.1365-2982.2008.01108.x -
The Journal of Physiology Apr 2022
Topics: Animals; Calcium; Drosophila; Excitation Contraction Coupling; Muscle Contraction; Muscles; Vertebrates
PubMed: 35138015
DOI: 10.1113/JP282642 -
The Journal of Experimental Biology Jan 2016A number of studies over the last few decades have established that the control strategy employed by the nervous system during lengthening (eccentric) differs from those... (Review)
Review
A number of studies over the last few decades have established that the control strategy employed by the nervous system during lengthening (eccentric) differs from those used during shortening (concentric) and isometric contractions. The purpose of this review is to summarize current knowledge on the neural control of lengthening contractions. After a brief discussion of methodological issues that can confound the comparison between lengthening and shortening actions, the review provides evidence that untrained individuals are usually unable to fully activate their muscles during a maximal lengthening contraction and that motor unit activity during submaximal lengthening actions differs from that during shortening actions. Contrary to common knowledge, however, more recent studies have found that the recruitment order of motor units is similar during submaximal shortening and lengthening contractions, but that discharge rate is systematically lower during lengthening actions. Subsequently, the review examines the mechanisms responsible for the specific control of maximal and submaximal lengthening contractions as reported by recent studies on the modulation of cortical and spinal excitability. As similar modulation has been observed regardless of contraction intensity, it appears that spinal and corticospinal excitability are reduced during lengthening compared with shortening and isometric contractions. Nonetheless, the modulation observed during lengthening contractions is mainly attributable to inhibition at the spinal level.
Topics: Animals; Humans; Isometric Contraction; Models, Biological; Muscle Contraction; Muscles; Nervous System Physiological Phenomena
PubMed: 26792331
DOI: 10.1242/jeb.123158