scholarly journals On the connection between the transverse tubules and the plasma membrane in frog semitendinosus skeletal muscle

1975 ◽  
Vol 64 (3) ◽  
pp. 734-740 ◽  
Author(s):  
G Zampighi ◽  
J Vergara ◽  
F Ramon
Keyword(s):  
Skeletal Muscle ◽  
Plasma Membrane ◽  
Muscle Fibers ◽  
Indirect Evidence ◽  
Electrical Signal ◽  
Ruthenium Red ◽  
Transitional Region ◽  
Transverse Tubular System ◽  
Pinocytotic Vesicles ◽  
And Function

The transverse tubular system (TTS) of skeletal muscle fibers represents the morphological basis for the inward spread of conduction of the electrical signal that triggers muscle contraction. A historical account of the main steps contributing to the elucidation of the structure and function of the TSS has been presented by Huxley (1971). While the localization of the TSS and its association with the sarcoplasmic reticulum (SR) is well documented; there is still a need further to develop our knowledge of the morphology of the connection between the TSS and the plasma membrane. It is generally believed that the TSS opens directly to the extracellular space and that there is continuity between its membrane and the sarcolemma. However, direct observation of such a connection has been clearly shown only for the myotome of fish (Franzini-Armstrong and Porter, 1964). In other muscle fibers, only indirect evidence of the connection has been provided by experiments showing penetration of extracellular tracers into the TSS. These extracellular markers were also observed inside another membrane-bounded compartment consisting of round profiles named "caveolae" (Yamada, 1955) or "pinocytotic vesicles" (Ashurst, 1969). The present study deals with the communication between the TTS, caveolae, and plasma membrane (Peachey, 1965); Ezerman and Ishikawa, 1967; Schiaffino and Margreth, 1968; and Rayns et al., 1968). A detailed study of the caveolae compartment was undertaken with ruthenium red as an electron-dense tracer. As a result of this study, we propose that in certain species the caveolae compartment represents the transitional region in the connection between the TSS and the sarcolemma.

scholarly journals The Recent Understanding of the Neurotrophin's Role in Skeletal Muscle Adaptation

2011 ◽  
Vol 2011 ◽  
pp. 1-12 ◽  
Author(s):  
Kunihiro Sakuma ◽  
Akihiko Yamaguchi
Keyword(s):  
Skeletal Muscle ◽  
Neuromuscular Disorders ◽  
Muscle Fibers ◽  
Brain Disorders ◽  
Muscle Adaptation ◽  
Bdnf Mrna ◽  
Pathological Conditions ◽  
Development And Differentiation ◽  
And Function

This paper summarizes the various effects of neurotrophins in skeletal muscle and how these proteins act as potential regulators of the maintenance, function, and regeneration of skeletal muscle fibers. Increasing evidence suggests that this family of neurotrophic factors influence not only the survival and function of innervating motoneurons but also the development and differentiation of myoblasts and muscle fibers. Muscle contractions (e.g., exercise) produce BDNF mRNA and protein in skeletal muscle, and the BDNF seems to play a role in enhancing glucose metabolism and may act for myokine to improve various brain disorders (e.g., Alzheimer's disease and major depression). In adults with neuromuscular disorders, variations in neurotrophin expression are found, and the role of neurotrophins under such conditions is beginning to be elucidated. This paper provides a basis for a better understanding of the role of these factors under such pathological conditions and for treatment of human neuromuscular disease.

Treadmill running causes significant fiber damage in skeletal muscle of KATP channel-deficient mice

2005 ◽  
Vol 22 (2) ◽  
pp. 204-212 ◽  
Author(s):  
M. Thabet ◽  
T. Miki ◽  
S. Seino ◽  
J.-M. Renaud
Keyword(s):  
Skeletal Muscle ◽  
Muscle Fibers ◽  
Treadmill Running ◽  
Wild Type ◽  
Connective Tissues ◽  
Fiber Damage ◽  
Hindlimb Muscles ◽  
Skeletal Muscle Fibers ◽  
And Function ◽  
Deficient Mice

Although it has been suggested that the ATP-sensitive K+ (KATP) channel protects muscle against function impairment, most studies have so far given little evidence for significant perturbation in the integrity and function of skeletal muscle fibers from inactive mice that lack KATP channel activity in their cell membrane. The objective was, therefore, to test the hypothesis that KATP channel-deficient skeletal muscle fibers become damaged when mice are subjected to stress. Wild-type and KATP channel-deficient mice (Kir6.2−/− mice) were subjected to 4–5 wk of treadmill running at either 20 m/min with 0° inclination or at 24 m/min with 20° uphill inclination. Muscles of all wild-type mice and of nonexercised Kir6.2−/− mice had very few fibers with internal nuclei. After 4–5 wk of treadmill running, there was little evidence for connective tissues and mononucleated cells in Kir6.2−/− hindlimb muscles, whereas the number of fibers with internal nuclei, which appear when damaged fibers are regenerated by satellite cells, was significantly higher in Kir6.2−/− than wild-type mice. Between 5% and 25% of the total number of fibers in Kir6.2−/− extensor digitum longus, plantaris, and tibialis muscles had internal nuclei, and most of such fibers were type IIB fibers. Contrary to hindlimb muscles, diaphragms of Kir6.2−/− mice that had run at 24 m/min had few fibers with internal nuclei, but mild to severe fiber damage was observed. In conclusion, the study provides for the first time evidence 1) that the KATP channels of skeletal muscle are essential to prevent fiber damage, and thus muscle dysfunction; and 2) that the extent of fiber damage is greater and the capacity of fiber regeneration is less in Kir6.2−/− diaphragm muscles compared with hindlimb muscles.

scholarly journals Immunohistochemical localization in normal tissues of different epitopes in the multidrug transport protein P170: evidence for localization in brain capillaries and crossreactivity of one antibody with a muscle protein.

1989 ◽  
Vol 37 (2) ◽  
pp. 159-164 ◽  
Author(s):  
F Thiebaut ◽  
T Tsuruo ◽  
H Hamada ◽  
M M Gottesman ◽  
I Pastan ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Plasma Membrane ◽  
Cardiac Muscle ◽  
Muscle Fibers ◽  
Transport Protein ◽  
Rat Tissues ◽  
Human Tissues ◽  
Normal Tissues ◽  
Skeletal Muscle Fibers ◽  
Muscle Myosin

Using peroxidase immunohistochemistry, we examined the distribution of P170, a multidrug transport protein, in normal tissues by use of two different monoclonal antibodies (MAb). MAb MRK16 is a MAb that has been shown to react with an epitope in P170 located on the external face of the plasma membrane of multidrug-resistant human cells. MAb C219 has been shown to react with P170 in many mammalian species, and detects an epitope located on the cytoplasmic face of the plasma membrane. Using MRK16, we have previously described the localization of P170 on the bile canalicular face of hepatocytes, the apical surface of proximal tubular cells in kidney, and the surface epithelium in the lower GI tract in normal human tissues. In this work, we report that MRK16 also detects P170 in the capillaries of some human brain samples. A similar pattern was found using MAb C219 in rat tissues. in addition, MAb C219 showed intense localization in selected skeletal muscle fibers and all cardiac muscle fibers in rat and human tissues. ATPase cytochemistry showed that these reactive skeletal muscle fibers were of the type I (slow-twitch) class. Other additional sites of C219 reactivity in rat tissues were found in pancreatic acini, seminal vesicle, and testis. Electrophoretic gel immunoblotting showed two protein bands reactive with MAb C219. In liver, MAb C219 reacted with a approximately 170 KD band. In skeletal and cardiac muscle, MAb C219 reacted with a approximately 200 KD band which migrated in the same position as myosin. This band also reacted with an antibody to skeletal muscle myosin. This result suggests that C219 may crossreact with the heavy chain of muscle myosin in cardiac and skeletal muscle. Because MAb C219 reacts with proteins other than P170, it should be used with caution in studies of multidrug resistance.

Characteristics of phosphate-induced Ca2+ efflux from the SR in mechanically skinned rat skeletal muscle fibers

2000 ◽  
Vol 278 (1) ◽  
pp. C126-C135 ◽  
Author(s):  
Adrian M. Duke ◽  
Derek S. Steele
Keyword(s):  
Skeletal Muscle ◽  
Creatine Kinase ◽  
Muscle Fibers ◽  
Cyclopiazonic Acid ◽  
Creatine Phosphate ◽  
Ruthenium Red ◽  
Rat Skeletal Muscle ◽  
Atpase Inhibitor ◽  
Skeletal Muscle Fibers ◽  
Efflux Pathway

The effects of Pi on sarcoplasmic reticulum (SR) Ca2+ regulation were studied in mechanically skinned rat skeletal muscle fibers. Brief application of caffeine was used to assess the SR Ca2+ content, and changes in concentration of Ca2+([Ca2+]) within the cytosol were detected with fura 2 fluorescence. Introduction of Pi (1–40 mM) induced a concentration-dependent Ca2+ efflux from the SR. In solutions lacking creatine phosphate (CP), the amplitude of the Pi-induced Ca2+ transient approximately doubled. A similar potentiation of Pi-induced Ca2+ release occurred after inhibition of creatine kinase (CK) with 2,4-dinitrofluorobenzene. In the presence of ruthenium red or ryanodine, caffeine-induced Ca2+ release was almost abolished, whereas Pi-induced Ca2+ release was unaffected. However, introduction of the SR Ca2+ ATPase inhibitor cyclopiazonic acid effectively abolished Pi-induced Ca2+ release. These data suggest that Pi induces Ca2+ release from the SR by reversal of the SR Ca2+ pump but not via the SR Ca2+ channel under these conditions. If this occurs in intact skeletal muscle during fatigue, activation of a Ca2+efflux pathway by Pi may contribute to the reported decrease in net Ca2+ uptake and increase in resting [Ca2+].

scholarly journals Calcium-gated calcium channels in sarcoplasmic reticulum of rabbit skinned skeletal muscle fibers.

1986 ◽  
Vol 87 (2) ◽  
pp. 289-303 ◽  
Author(s):  
P Volpe ◽  
G Salviati ◽  
A Chu
Keyword(s):  
Skeletal Muscle ◽  
Sarcoplasmic Reticulum ◽  
Isometric Force ◽  
Muscle Fibers ◽  
Ruthenium Red ◽  
Scattering Method ◽  
Tension Development ◽  
Maximal Force ◽  
Skeletal Muscle Fibers ◽  
Ca2 Channels

The action of ruthenium red (RR) on Ca2+ loading by and Ca2+ release from the sarcoplasmic reticulum (SR) of chemically skinned skeletal muscle fibers of the rabbit was investigated. Ca2+ loading, in the presence of the precipitating anion pyrophosphate, was monitored by a light-scattering method. Ca2+ release was indirectly measured by following tension development evoked by caffeine. Stimulation of the Ca2+ loading rate by 5 microM RR was dependent on free Ca2+, being maximal at pCa 5.56. Isometric force development induced by 5 mM caffeine was reversibly antagonized by RR. IC50 for the rate of tension rise was 0.5 microM; that for the extent of tension was 4 microM. RR slightly shifted the steady state isometric force/pCa curve toward lower pCa values. At 5 microM RR, the pCa required for half-maximal force was 0.2 log units lower than that of the control, and maximal force was depressed by approximately 16%. These results suggest that RR inhibited Ca2+ release from the SR and stimulated Ca2+ loading into the SR by closing Ca2+-gated Ca2+ channels. Previous studies on isolated SR have indicated the selective presence of such channels in junctional terminal cisternae.

scholarly journals Adiponectin is expressed by skeletal muscle fibers and influences muscle phenotype and function

2008 ◽  
Vol 295 (1) ◽  
pp. C203-C212 ◽  
Author(s):  
Matthew P. Krause ◽  
Ying Liu ◽  
Vivian Vu ◽  
Lawrence Chan ◽  
Aimin Xu ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Fiber Type ◽  
Muscle Fibers ◽  
Low Frequency ◽  
Disease States ◽  
L6 Myotubes ◽  
Type Composition ◽  
Low Frequency Fatigue ◽  
And Function

Adiponectin (Ad) is linked to various disease states and mediates antidiabetic and anti-inflammatory effects. While it was originally thought that Ad expression was limited to adipocytes, we demonstrate here that Ad is expressed in mouse skeletal muscles and within differentiated L6 myotubes, as assessed by RT-PCR, Western blot, and immunohistochemical analyses. Serial muscle sections stained for fiber type, lipid content, and Ad revealed that muscle fibers with elevated intramyocellular Ad expression were consistently type IIA and IID fibers with detectably higher intramyocellular lipid (IMCL) content. To determine the effect of Ad on muscle phenotype and function, we used an Ad-null [knockout (KO)] mouse model. Body mass increased significantly in 24-wk-old KO mice [+5.5 ± 3% relative to wild-type mice (WT)], with no change in muscle mass observed. IMCL content was significantly increased (+75.1 ± 25%), whereas epididymal fat mass, although elevated, was not different in the KO mice compared with WT (+35.1 ± 23%; P = 0.16). Fiber-type composition was unaltered, although type IIB fiber area was increased in KO mice (+25.5 ± 6%). In situ muscle stimulation revealed lower peak tetanic forces in KO mice relative to WT (−47.5 ± 6%), with no change in low-frequency fatigue rates. These data demonstrate that the absence of Ad expression causes contractile dysfunction and phenotypical changes in skeletal muscle. Furthermore, we demonstrate that Ad is expressed in skeletal muscle and that its intramyocellular localization is associated with elevated IMCL, particularly in type IIA/D fibers.

The core cylinder in the junctional SR of single intact skeletal muscle fibers of the frog after quick-freezing: Its topography

1983 ◽  
Vol 41 ◽  
pp. 648-649
Author(s):  
J.R. Sommer ◽  
R. Nassar ◽  
B. Scherer
Keyword(s):  
Skeletal Muscle ◽  
Muscle Fibers ◽  
Ruthenium Red ◽  
One Dimension ◽  
The Core ◽  
Quick Freezing ◽  
Clear Halo ◽  
Circular Configuration ◽  
Consistent Feature ◽  
Electron Lucent

The "core cylinder" (CC) represents confluent electron lucencies seen in the junctional SR (JSR) when skeletal muscle is fixed in the presence of cations such as ruthenium red. CCs are a consistent feature in quick-frozen muscle fibers (Fig.l), both in the resting state and after various intervals between stimulation and freezing, incl. tetanus (5 sec, 50Hz). The CCs are excentrically located inside the JSR and are separated from the junctional membrane toward the transverse tubule by the coextensive line(CL) and from the rest of the membranous envelope of the JSR by granular material (junctional granules, JG). JGs are also found elsewhere in the free SR. Whereas the JGs fill the JSR completely in many cases, often they are separated from the JSR envelope by a peripheral clear halo except in the region of the CL; in favourable sections they form regular rosettes about the CC (Fig.3). Very frequently, the CC loose their more circular configuration (in one dimension)(Fig.4), with flares connecting the CCs with the peripheral halo at either end of the CL (Fig.3). The junction between the electron-lucent flares and the ends of the CL subtends, approximately, the location of the staggered rows of pits on the E face of the freeze-fractured JSR(Fig.2).

The core cylinder of the JSR of frog skeletal muscle in cryosections

1987 ◽  
Vol 45 ◽  
pp. 414-415
Author(s):  
J. R. Sommer ◽  
T. High ◽  
P. Ingram
Keyword(s):  
Skeletal Muscle ◽  
Carbon Film ◽  
Ruthenium Red ◽  
Frog Skeletal Muscle ◽  
Turbomolecular Pump ◽  
Freeze Dried ◽  
Quick Freezing ◽  
And Function ◽  
Electron Lucent ◽  
Junctional Sarcoplasmic Reticulum

Electron-lucent regions in the junctional sarcoplasmic reticulum (JSR) were first observed in frog skeletal muscle treated with ruthenium red and other exotic cations. Next, they were pointed out in Epon sections of freeze-substituted muscle following quick-freezing both in the presence and absence of cryoartifacts. Whereas their nature and function remain obscure, the so-called “core cylinders” (CCs) are now considered invariant components of the normal anatomy of frog skeletal muscle JSR.Following quick-freezing, part of the single intact frog skeletal muscle fiber was freeze-substituted, embedded in Epon and sectioned (Fig. 1). Cryosections were cut from an immediately adjacent fiber region with a diamond knife specially mounted for that purpose with two free edges (courtesy Diatome-US), on a Reichert Ultracut FC-4D at -150°C, put on the carbon film on 100 mesh nickel grids, freeze-dried in a Balzers FDU 010 fitted with a turbomolecular pump (vac 10-6 torr) against a liquid N2 trap (geometry 14 mm) for 15 hrs with 3 temperature steps, each 3 hrs apart, at -100, -85, and -50°C, respectively (Fig. 2).

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