Optical evidence for a chloride conductance in the T-system of frog skeletal muscle

1990 ◽  
Vol 416 (3) ◽  
pp. 288-295 ◽  
Author(s):  
J. A. Heiny ◽  
J. R. Valle ◽  
S. H. Bryant
Keyword(s):  
Skeletal Muscle ◽  
Chloride Conductance ◽  
Frog Skeletal Muscle ◽  
Optical Evidence ◽  
T System

scholarly journals The T-SR junction in contracting single skeletal muscle fibers.

1982 ◽  
Vol 79 (1) ◽  
pp. 1-19 ◽  
Author(s):  
B R Eisenberg ◽  
R S Eisenberg
Keyword(s):  
Skeletal Muscle ◽  
Sarcoplasmic Reticulum ◽  
Amorphous Material ◽  
Frog Skeletal Muscle ◽  
Contraction Coupling ◽  
Single Fibers ◽  
Line Parallel ◽  
Rich Solution ◽  
Electron Lucent ◽  
T System

The junction between the T system and sarcoplasmic reticulum (SR) of frog skeletal muscle was examined in resting and contracting muscles. Pillars, defined as pairs of electron-opaque lines bounding an electron-lucent interior, were seen spanning the gap between T membrane and SR. Feet, defined previously in images of heavily stained preparations, appear with electron-opaque interiors and as such are distinct from the pillars studied here. Amorphous material was often present in the gap between T membrane and SR. Sometimes the amorphous material appeared as a thin line parallel to the membranes; sometimes it seemed loosely organized at the sites where feet have been reported. Resting single fibers contained 39 +/- 14.3 (mean +/- SD; n = 9 fibers) pillars/micrometer2 of tubule membrane. Single fibers, activated by a potassium-rich solution at 4 degrees C, contained 66 +/- 12.9 pillars/micrometer2 (n = 8) but fibers contracting in response to 2 mM caffeine contained 33 +/- 8.6/micrometer2 (n = 5). Pillar formation occurs when fibers are activated electrically, but not when calcium is released directly from the SR; and so we postulate that pillar formation is a step in excitation-contraction coupling.

Kinetic analysis of chloride conductance in frog skeletal muscle at pH 5

1991 ◽  
Vol 419 (5) ◽  
pp. 522-528 ◽  
Author(s):  
Peter Vaughan ◽  
J. Mailen Kootsey ◽  
Michael D. Feezor
Keyword(s):  
Skeletal Muscle ◽  
Kinetic Analysis ◽  
Chloride Conductance ◽  
Frog Skeletal Muscle

scholarly journals COMPARISON OF GLYCEROL TREATMENT IN FROG SKELETAL MUSCLE AND MAMMALIAN HEART

1971 ◽  
Vol 50 (2) ◽  
pp. 288-299 ◽  
Author(s):  
G. Niemeyer ◽  
W. G. Forssmann
Keyword(s):  
Skeletal Muscle ◽  
Heart Muscle ◽  
Frog Skeletal Muscle ◽  
Mammalian Heart ◽  
Glycerol Treatment ◽  
Before And After ◽  
Tracer Methods ◽  
Mammalian Heart Muscle ◽  
T System

Frog skeletal muscle and mammalian heart muscle were studied in vitro before and after glycerol treatment. Loss of contractility, changes in the action potential and disruption of the T system were observed in skeletal muscle cells. In mammalian heart muscle the T system was not disrupted with hypertonic glycerol treatment, and no significant electrophysiological changes were observed. The continuity between the T system and the extracellular space was investigated by diffusion tracer methods. Decrease of contractility during the hypertonic phase in the glycerol treatment was found to depend on tonicity. The results of this study clearly show that not only are there differences in morphology between skeletal and cardiac muscle, but there are also differences in the resistance to osmotic changes.

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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