The First Thin Filament Layer Line Decreases in Intensity During an Isometric Contraction of Frog Skeletal Muscle

1993 ◽  
pp. 451-460 ◽  
Author(s):  
Katsuzo Wakabayashi ◽  
Hideaki Saito ◽  
Noriyoshi Moriwaki ◽  
Takakazu Kobayashi ◽  
Hidehiro Tanaka
Keyword(s):  
Skeletal Muscle ◽  
Isometric Contraction ◽  
Thin Filament ◽  
Frog Skeletal Muscle ◽  
Layer Line

scholarly journals Intensity changes of the first and second thin-filament layer-lines of a frog skeletal muscle during isometric contraction

2000 ◽  
Vol 40 (supplement) ◽  
pp. S64
Author(s):  
Y. Takezawa ◽  
T. Kobayashi ◽  
Y. Sugimoto ◽  
K. Wakabayashi
Keyword(s):  
Skeletal Muscle ◽  
Isometric Contraction ◽  
Thin Filament ◽  
Frog Skeletal Muscle ◽  
Intensity Changes

Effects of intracellular acidosis on Ca2+ activation, contraction, and relaxation of frog skeletal muscle

1995 ◽  
Vol 268 (1) ◽  
pp. C55-C63 ◽  
Author(s):  
A. J. Baker ◽  
R. Brandes ◽  
M. W. Weiner
Keyword(s):  
Skeletal Muscle ◽  
Thin Filament ◽  
Frog Skeletal Muscle ◽  
Intracellular Acidosis ◽  
Tetanic Force ◽  
Force Relaxation ◽  
Cross Bridges ◽  
Contraction And Relaxation ◽  
Initial Force ◽  
Force Relationship

The goal of this study was to determine the effects of intracellular acidosis (pH approximately 6.3) of frog skeletal muscle on force and on intracellular Ca2+ concentration ([Ca2+]i; measured at 20 degrees C using indo 1 fluorescence). Acidosis reduced tetanic force by only 11 +/- 2% (mean +/- SE, n = 8) but increased tetanic [Ca2+]i by 33 +/- 6%, suggesting that acidosis reduced the maximum Ca(2+)-activated force. During relaxation, the [Ca2+]i at half-maximal force was doubled with acidosis, suggesting that acidosis altered the Ca(2+)-force relationship. Acidosis markedly slowed force relaxation and [Ca2+]i decline (time constants fitted to force and [Ca2+]i during relaxation increased by 133 +/- 20 and 68 +/- 13%, respectively, with acidosis), suggesting that slowed force relaxation with acidosis may arise from slowed Ca2+ clearance from the cytosol. Late in relaxation, at approximately 30% of initial force, there was a transient phase of [Ca2+]i increase that was delayed with acidosis in proportion to the slowing of force relaxation. This is consistent with previous suggestions that dissociation of cross-bridges from the thin filament during relaxation promotes Ca2+ release to the cytosol from troponin. This study concludes that in skeletal muscle acidosis has little effect on tetanic force and that the major effects are decreased Ca2+ sensitivity and slower relaxation.

Ultra-Rapid Freezing of Isolated Skeletal Muscle Fibers

1977 ◽  
Vol 35 ◽  
pp. 576-577
Author(s):  
Joachim R. Sommer ◽  
Nancy R. Wallace
Keyword(s):  
Skeletal Muscle ◽  
Sarcoplasmic Reticulum ◽  
Granular Material ◽  
Nuclear Envelope ◽  
Intracellular Calcium ◽  
Ruthenium Red ◽  
Threshold Concentration ◽  
Rapid Freezing ◽  
Frog Skeletal Muscle ◽  
Electrical Isolation

After Howell (1) had shown that ruthenium red treatment of fixed frog skeletal muscle caused collapse of the intermediate cisternae of the sarcoplasmic reticulum (SR), forming a pentalaminate structure by obi iterating the SR lumen, we demonstrated that the phenomenon involves the entire SR including the nuclear envelope and that it also occurs after treatment with other cations, including calcium (2,3,4).From these observations we have formulated a hypothesis which states that intracellular calcium taken up by the SR at the end of contraction causes the M rete to collapse at a certain threshold concentration as the first step in a subsequent centrifugal zippering of the free SR toward the junctional SR (JSR). This would cause a) bulk transport of SR contents, such as calcium and granular material (4) into the JSR and, b) electrical isolation of the free SR from the JSR.

Electron Probe Analysis of Muscle

1982 ◽  
Vol 40 ◽  
pp. 398-401
Author(s):  
A. V. Somlyo ◽  
H. Shuman ◽  
A. P. Somlyo
Keyword(s):  
Skeletal Muscle ◽  
Smooth Muscle ◽  
Sarcoplasmic Reticulum ◽  
Resting State ◽  
Binding Sites ◽  
Electron Probe ◽  
Frog Skeletal Muscle ◽  
Electron Probe Analysis ◽  
Probe Analysis

Electron probe analysis of frozen dried cryosections of frog skeletal muscle, rabbit vascular smooth muscle and of isolated, hyperpermeab1 e rabbit cardiac myocytes has been used to determine the composition of the cytoplasm and organelles in the resting state as well as during contraction. The concentration of elements within the organelles reflects the permeabilities of the organelle membranes to the cytoplasmic ions as well as binding sites. The measurements of [Ca] in the sarcoplasmic reticulum (SR) and mitochondria at rest and during contraction, have direct bearing on their role as release and/or storage sites for Ca in situ.

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