scholarly journals The Structure of Mytilus Smooth Muscle and the Electrical Constants of the Resting Muscle

1973 ◽  
Vol 61 (2) ◽  
pp. 207-221 ◽  
Author(s):  
Betty M. Twarog ◽  
Maynard M. Dewey ◽  
Tohoru Hidaka
Keyword(s):  
Connective Tissue ◽  
Muscle Fibers ◽  
Smooth Muscles ◽  
Input Resistance ◽  
Muscle Membrane ◽  
Retractor Muscle ◽  
Current Passing ◽  
Individual Muscle ◽  
The Individual ◽  
Resting Muscle

The individual muscle fibers of the anterior byssus retractor muscle (ABRM) of Mytilus edulis L. are uninucleate, 1.2–1.8 mm in length, 5 µm in diameter, and organized into bundles 100–200 µm in diameter, surrounded by connective tissue. Some bundles run the length of the whole muscle. Adjacent muscle cell membranes are interconnected by nexuses at frequent intervals. Specialized attachments exist between muscle fibers and connective tissue. Electrical constants of the resting muscle membrane were measured with intracellular recording electrodes and both extracellular and intracellular current-passing electrodes. With an intracellular current-passing electrode, the time constant τ, was 4.3 ± 1.5 ms. With current delivered via an extracellular electrode τ was 68.3 ± 15 ms. The space constant, λ, was 1.8 mm ± 0.4. The membrane input resistance, Reff, ranged from 23 to 51 MΩ. The observations that values of τ depend on the method of passing current, and that the value of λ is large relative to fiber length and diameter are considered evidence that the individual muscle fibers are electrically interconnected within bundles in a three-dimensional network. Estimations are made of the membrane resistance, Rm, to compare the values to fast and slow striated muscle fibers and mammalian smooth muscles. The implications of this study in reinterpreting previous mechanical and electrical studies are discussed.

Intracellular calcium translocation during contraction in vertebrate and invertebrate smooth muscles as studied by the pyroantimonate method

1982 ◽  
Vol 60 (4) ◽  
pp. 576-587 ◽  
Author(s):  
Haruo Sugi ◽  
Suechika Suzuki ◽  
Tateo Daimon
Keyword(s):  
Smooth Muscle ◽  
Plasma Membrane ◽  
Coronary Artery ◽  
Intracellular Localization ◽  
Muscle Fibers ◽  
Smooth Muscles ◽  
Electron Microscopic Examination ◽  
Mechanical Activity ◽  
Retractor Muscle ◽  
Electron Microscopic

The intracellular localization of activator Ca and its translocation during the mechanical activity were studied on vertebrate and invertebrate smooth muscles by fixing muscle fibers with a 1% OsO4 solution containing 2% potassium pyroantimonate for electron microscopic examination. When guinea-pig tacnia coli, Mytilus anterior byssal retractor muscle, and Dorabella longitudinal body wall muscle were fixed during the relaxed state, electron-opaque pyroantimonate precipitate containing Ca was localized along the inner surface of the plasma membrane and at other membranous structures in close apposition to the plasma membrane, in accordance with physiological evidence that these muscles contain intracellularly stored activator Ca. When they were fixed during the contracted state, the precipitate was distributed diffusely in the myoplasm in the form of small particles, indicating the release of activator Ca from the peripheral structures. The contraction in dog coronary artery smooth muscle appears to be associated with the inward movement of extracellular Ca. In accordance with this, the resting coronary artery muscle fibers exhibited the precipitate in the lumen of the caveolae, i.e., the bottle-shaped plasma membrane invaginations, but not at the peripheral intracellular structures, though the contracted fibers showed the diffuse distribution of the precipitate in the myoplasm. These results indicate that the pyroantimonate method is very effective in studying the translocation of activator Ca in various types of smooth muscle.

scholarly journals Influence of layer separation on the determination of stomach smooth muscle properties

2021 ◽  
Author(s):  
Mischa Borsdorf ◽  
Markus Böl ◽  
Tobias Siebert
Keyword(s):  
Smooth Muscle ◽  
Muscle Fibers ◽  
Smooth Muscles ◽  
Muscle Layer ◽  
Uniaxial Tensile ◽  
Muscle Properties ◽  
Layer Separation ◽  
Isotonic Contractions ◽  
Longitudinal Layer

AbstractUniaxial tensile experiments are a standard method to determine the contractile properties of smooth muscles. Smooth muscle strips from organs of the urogenital and gastrointestinal tract contain multiple muscle layers with different muscle fiber orientations, which are frequently not separated for the experiments. During strip activation, these muscle fibers contract in deviant orientations from the force-measuring axis, affecting the biomechanical characteristics of the tissue strips. This study aimed to investigate the influence of muscle layer separation on the determination of smooth muscle properties. Smooth muscle strips, consisting of longitudinal and circumferential muscle layers (whole-muscle strips [WMS]), and smooth muscle strips, consisting of only the circumferential muscle layer (separated layer strips [SLS]), have been prepared from the fundus of the porcine stomach. Strips were mounted with muscle fibers of the circumferential layer inline with the force-measuring axis of the uniaxial testing setup. The force–length (FLR) and force–velocity relationships (FVR) were determined through a series of isometric and isotonic contractions, respectively. Muscle layer separation revealed no changes in the FLR. However, the SLS exhibited a higher maximal shortening velocity and a lower curvature factor than WMS. During WMS activation, the transversally oriented muscle fibers of the longitudinal layer shortened, resulting in a narrowing of this layer. Expecting volume constancy of muscle tissue, this narrowing leads to a lengthening of the longitudinal layer, which counteracted the shortening of the circumferential layer during isotonic contractions. Consequently, the shortening velocities of the WMS were decreased significantly. This effect was stronger at high shortening velocities.

The KATP channel Kir6.2 subunit content is higher in glycolytic than oxidative skeletal muscle fibers

2011 ◽  
Vol 301 (4) ◽  
pp. R916-R925 ◽  
Author(s):  
Krystyna Banas ◽  
Charlene Clow ◽  
Bernard J. Jasmin ◽  
Jean-Marc Renaud
Keyword(s):  
Skeletal Muscle ◽  
Cross Sections ◽  
Fiber Type ◽  
Energy Levels ◽  
Muscle Fibers ◽  
Metabolic Stress ◽  
Oxidative Capacity ◽  
Fiber Types ◽  
Fiber Damage ◽  
The Individual

It has long been suggested that in skeletal muscle, the ATP-sensitive K+ channel (KATP) channel is important in protecting energy levels and that abolishing its activity causes fiber damage and severely impairs function. The responses to a lack of KATP channel activity vary between muscles and fibers, with the severity of the impairment being the highest in the most glycolytic muscle fibers. Furthermore, glycolytic muscle fibers are also expected to face metabolic stress more often than oxidative ones. The objective of this study was to determine whether the t-tubular KATP channel content differs between muscles and fiber types. KATP channel content was estimated using a semiquantitative immunofluorescence approach by staining cross sections from soleus, extensor digitorum longus (EDL), and flexor digitorum brevis (FDB) muscles with anti-Kir6.2 antibody. Fiber types were determined using serial cross sections stained with specific antimyosin I, IIA, IIB, and IIX antibodies. Changes in Kir6.2 content were compared with changes in CaV1.1 content, as this Ca2+ channel is responsible for triggering Ca2+ release from sarcoplasmic reticulum. The Kir6.2 content was the lowest in the oxidative soleus and the highest in the glycolytic EDL and FDB. At the individual fiber level, the Kir6.2 content within a muscle was in the order of type IIB > IIX > IIA ≥ I. Interestingly, the Kir6.2 content for a given fiber type was significantly different between soleus, EDL, and FDB, and highest in FDB. Correlations of relative fluorescence intensities from the Kir6.2 and CaV1.1 antibodies were significant for all three muscles. However, the variability in content between the three muscles or individual fibers was much greater for Kir6.2 than for CaV1.1. It is suggested that the t-tubular KATP channel content increases as the glycolytic capacity increases and as the oxidative capacity decreases and that the expression of KATP channels may be linked to how often muscles/fibers face metabolic stress.

Smooth muscles from spastic coronary artery segments show hypercontractility to histamine

1990 ◽  
Vol 259 (1) ◽  
pp. H9-H13 ◽  
Author(s):  
S. Satoh ◽  
H. Tomoike ◽  
W. Mitsuoka ◽  
S. Egashira ◽  
H. Tagawa ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Coronary Artery ◽  
Coronary Arteries ◽  
Muscle Fibers ◽  
Coronary Spasm ◽  
Smooth Muscles ◽  
Bolus Administration ◽  
Luminal Diameter ◽  
Endothelial Denudation ◽  
Significant Difference

An animal model of coronary spasm was produced in Gottingen miniature pigs by a selective endothelial denudation of the coronary artery. Five months after the denudation, intracoronary bolus administration of 10 micrograms/kg histamine reduced the luminal diameter angiographically by 57 +/- 16 and 17 +/- 10% (P less than 0.01) in the previously denuded and contralateral control coronary arteries. Muscle fibers of 0.08–0.1 mm wide were prepared from circumferential bundles of the medial smooth muscle in the spastic and nonspastic coronary arteries. Upward shifts of either dose-tonic contraction relationships in Ca2(+)-containing solution or dose-monophasic contraction relationships in Ca2(+)-free solution were noted in muscle fibers taken from the spastic site compared with those from the nonspastic site with no difference between the mean effective dose values. After skinning the muscle fibers with saponin, there was no significant difference in the Ca2+ concentration-tension relationships between the two fibers. These findings suggest that an increased number of histaminergic receptors and/or augmentation of signal transduction, but not Ca2+ sensitivity of the contractile proteins in the medial smooth muscle cells, cause histamine-induced coronary hypercontraction.

Effect of Duchenne muscular dystrophy on enzymes of energy metabolism in individual muscle fibers

Metabolism ◽  
1987 ◽  
Vol 36 (8) ◽  
pp. 761-767 ◽  
Author(s):  
Maggie M.-Y. Chi ◽  
Carol S. Hintz ◽  
Deidre McKee ◽  
Steven Felder ◽  
Natasha Grant ◽  
...  
Keyword(s):  
Duchenne Muscular Dystrophy ◽  
Energy Metabolism ◽  
Muscular Dystrophy ◽  
Muscle Fibers ◽  
Individual Muscle ◽  
Enzymes Of Energy Metabolism

Effect of microgravity on metabolic enzymes of individual muscle fibers

1990 ◽  
Vol 4 (1) ◽  
pp. 55-63 ◽  
Author(s):  
Jill K. Manchester ◽  
Maggie M.‐Y. Chi ◽  
Beverly Norris ◽  
Bernard Ferrier ◽  
Igor Krasnov ◽  
...  
Keyword(s):  
Muscle Fibers ◽  
Metabolic Enzymes ◽  
Individual Muscle

scholarly journals Myositis in mixed connective tissue disease: a unique syndrome characterized by immunohistopathologic elements of both polymyositis and dermatomyositis

2004 ◽  
Vol 62 (4) ◽  
pp. 923-934 ◽  
Author(s):  
Maria Angela A.G. Vianna ◽  
Claudia T.L. Borges ◽  
Eduardo F. Borba ◽  
Maria Teresa C. Caleiro ◽  
Eloisa Bonfá ◽  
...  
Keyword(s):  
Connective Tissue ◽  
Connective Tissue Disease ◽  
Mixed Connective Tissue Disease ◽  
Muscle Fibers ◽  
Membrane Attack Complex ◽  
Inflammatory Cells ◽  
Vascular Involvement ◽  
Mhc I ◽  
Immune Mediated ◽  
Cellular Immune

OBJECTIVE: To characterize the inflammatory cells, the expression pattern of adhesion molecules (ICAM-1 and VCAM-1), membrane attack complex (C5b-9), and major histocompatibility complex (MHC) antigens in muscle biopsy of mixed connective tissue disease (MCTD). METHOD: We studied 14 patients with MCTD, and compared to 8 polimyositis (PM) patients, 5 dermatomyositis (DM) and 4 dystrophies. Inflammatory cells were examined for CD4+, CD8+, memory and naïve T cells, natural killer cells, and macrophages. Expression of MHC-I and -II, ICAM-1, VCAM-1 and C5b -9 were characterized on muscle fibers and vessels. RESULTS: Morphological analysis displayed a pattern of PM. Immunohistochemical study revealed a decreased number of capillaries, predominance of CD4+ and B cells in perivascular regions and predominance of CD8+ and CD45RO+ in endomysial regions. The expression of MHC-I on vessels and on degenerated muscle fibers, MHC-II expression on vessels and perifascicular muscle fibers, and the expression of ICAM-1 / VCAM-1 on endothelial cells indicated both vascular and cellular-immune mediated processes causing the muscular lesion. CONCLUSION:Our findings revealed a mixed mechanism in MCTD, both vascular involvement as DM, and cell-mediated like PM.

scholarly journals Pengaruh Range of Motion (ROM) Aktif Terhadap Fleksibilitas Sendi Lutut Pada Lanjut Usia

2020 ◽  
Vol 1 (1) ◽  
pp. 13-16
Author(s):  
Tavip Indrayana ◽  
Warijan Warijan ◽  
Joni Siswanto
Keyword(s):  
Connective Tissue ◽  
Knee Joint ◽  
Muscle Fibers ◽  
Sampling Technique ◽  
The Elderly ◽  
Before And After ◽  
Post Test ◽  
Quasi Experimental ◽  
The Right ◽  
Average Angle

ABSTRACTBackground : Joint flexibility decreases in old age due to a degenerative process resulting in changes in joints, connective tissue and cartilage in the elderly. Decreasing flexibility is also due to reduced elasticity of muscle fibers, where connective tissue in muscle fibers increases (Mariyam, 2008).Objective : The aim of this study was to analyze the effect of active exercise (ROM) on the lower extremities on increasing the flexibility of the knee joint in the elderlyMethods : This study using a quasi-experimental approach with One group pre-test and post-test design. The sampling technique uses the Slovin method of 42 people, obtained a sample of 25 elderly. Exercise is done twice a day for 8 days. Measurements were made on day 1, day 4 and day 8 of the study using a Goniometer measuring instrument..Result : The results of measurement I average of the right knee joint 117.52o, measurement II = 122.24, measurement III = 126, 36o. From the analysis with Paired simple t-Test between the measurements I and II, it was found that the different test measurements I and II t count value was equal to -1.908 with 0.068. Because sig 0.05, it can be concluded that Ho is accepted, meaning that the average angle of ROM before and after training is the same (not different). In the different test measurements II and III the value of t count is equal to -2.152 with sig 0.042.Conclusion : Because sig 0.05, it can be concluded that Ho is rejected, meaning that there is a difference in ROM angle after training between days 4 to 8 with the first day to day 4. Thus it can be stated that active ROM exercises affect the angle of ROM of the knee joint elderly after exercise ROM between day 4 to day 8. Keywords: active ROM exercise, flexibility of knee joint, elderly.

scholarly journals Motoneuron output regulated by ionic channels: a modeling study of motoneuron frequency-current relationships during fictive locomotion

2018 ◽  
Vol 120 (4) ◽  
pp. 1840-1858 ◽  
Author(s):  
Yue Dai ◽  
Yi Cheng ◽  
Brent Fedirchuk ◽  
Larry M. Jordan ◽  
Junhao Chu
Keyword(s):  
Input Resistance ◽  
Ionic Channels ◽  
Motor Output ◽  
Membrane Properties ◽  
Fictive Locomotion ◽  
State Dependent ◽  
Simulation Results ◽  
The Individual ◽  
Ionic Basis ◽  
Frequency Current

Cat lumbar motoneurons display changes in membrane properties during fictive locomotion. These changes include reduction of input resistance and afterhyperpolarization, hyperpolarization of voltage threshold, and voltage-dependent excitation of the motoneurons. The state-dependent alteration of membrane properties leads to dramatic changes in frequency-current (F-I) relationship. The mechanism underlying these changes remains unknown. Using a motoneuron model combined with electrophysiological data, we investigated the channel mechanisms underlying the regulation of motoneuronal excitability and motor output. Simulation results showed that upregulation of transient sodium, persistent sodium, or Cav1.3 calcium conductances or downregulation of calcium-activated potassium or KCNQ/Kv7 potassium conductances could increase motoneuronal excitability and motor output through hyperpolarizing (left shifting) the F-I relationships or increasing the F-I slopes, whereas downregulation of input resistance or upregulation of potassium-mediated leak conductance produced the opposite effects. The excitatory phase of locomotor drive potentials (LDPs) also substantially hyperpolarized the F-I relationships and increased the F-I slopes, whereas the inhibitory phase of the LDPs had opposite effects to a similar extent. The simulation results also showed that none of the individual channel modulations could produce all the changes in the F-I relationships. The effects of modulation of Cav1.3 and KCNQ/Kv7 on F-I relationships were supported by slice experiments with the Cav1.3 agonist Bay K8644 and the KCNQ/Kv7 antagonist XE-991. The conclusion is that the varying changes in F-I relationships during fictive locomotion could be regulated by multichannel modulations. This study provides insight into the ionic basis for control of motor output in walking. NEW & NOTEWORTHY Mammalian spinal motoneurons have their excitability adapted to facilitate recruitment and firing during locomotion. Cat lumbar motoneurons display dramatic changes in membrane properties during fictive locomotion. These changes lead to a varying alteration of frequency-current relationship. The mechanisms underlying the changes remain unknown. In particular, little is known about the ionic basis for regulation of motoneuronal excitability and thus control of the motor output for walking by the spinal motor system.

A fluid-driven soft robotic fish inspired by fish muscle architecture

2022 ◽  
Author(s):  
Sijia Liu ◽  
Yingjie Wang ◽  
Zhennan Li ◽  
Miao Jin ◽  
Lei Ren ◽  
...  
Keyword(s):  
Connective Tissue ◽  
Structural Design ◽  
Muscle Fibers ◽  
The Body ◽  
Optimum Frequency ◽  
Muscle System ◽  
Key Innovation ◽  
Biological Studies ◽  
Passive Deformation ◽  
Red Muscle

Abstract Artificial fish-like robots developed to date often focus on the external morphology of fish and have rarely addressed the contribution of the structure and morphology of biological muscle. However, biological studies have proven that fish utilize the contraction of muscle fibers to drive the protective flexible connective tissue to swim. This paper introduces a pneumatic silicone structure prototype inspired by the red muscle system of fish and applies it to the fish-like robot named Flexi-Tuna. The key innovation is to make the fluid-driven units simulate the red muscle fiber bundles of fish and embed them into a flexible tuna-like matrix. The driving units act as muscle fibers to generate active contraction force, and the flexible matrix as connective tissue to generate passive deformation. Applying alternant pressure to the driving units can produce a bending moment, causing the tail to swing. As a result, the structural design of Flexi-Tuna has excellent bearing capacity compared with the traditional cavity-type and keeps the body smooth. On this basis, a general method is proposed for modeling the fish-like robot based on the independent analysis of the active and passive body, providing a foundation for Flexi-Tuna’s size design. Followed by the robot’s static and underwater dynamic tests, we used finite element static analysis and fluid numerical simulation to compare the results. The experimental results showed that the maximum swing angle of the tuna-like robot reached 20°, and the maximum thrust reached 0.185 N at the optimum frequency of 3.5 Hz. In this study, we designed a unique system that matches the functional level of biological muscles. As a result, we realized the application of fluid-driven artificial muscle to bionic fish and expanded new ideas for the structural design of flexible bionic fish.

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