Hg2+-induced contracture in mechanically skinned fibers of frog skeletal muscle

1985 ◽  
Vol 63 (9) ◽  
pp. 1070-1074 ◽  
Author(s):  
Takako Aoki ◽  
Toshiharu Oba ◽  
Ken Hotta
Keyword(s):  
Skeletal Muscle ◽  
Sarcoplasmic Reticulum ◽  
Sulfhydryl Groups ◽  
Skinned Fibers ◽  
Frog Skeletal Muscle ◽  
Semitendinosus Muscle ◽  
Skinned Fiber ◽  
Brij 58 ◽  
Develop Tension

In mechanically skinned fibers of the semitendinosus muscle of bullfrogs, we examined the role of membrane sulfhydryl groups on Ca2+ release from the sarcoplasmic reticulum (SR). Hg2+, a sulfhydryl reagent (20–100 μM), induced a repetitive contracture of skinned fibers, and this contracture did not occur in skinned fibers in which the SR had been disrupted by treatment with a detergent (Brij 58). Procaine (10 mM), Mg2+ (5 mM), or dithiothreitol (1 mM) blocked the Hg2+-induced contracture. Ag+ or p-chloromercuribenzenesulfonic acid produced similar contractures to that induced by Hg2+. We conclude that Hg2+ releases Ca2+ from SR of a skinned fiber by modifying sulfhydryl groups on the SR membrane, and suggest that the Ca2+ released by Hg2+ may trigger a greater release of Ca2+ from SR to develop tension.

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.

Caffeine treatment inhibits drug-induced calcium release from sarcoplasmic reticulum and caffeine contracture but not tetanus in frog skeletal muscle

1989 ◽  
Vol 67 (8) ◽  
pp. 890-895 ◽  
Author(s):  
Makoto Koshita ◽  
Toshiharu Oba
Keyword(s):  
Skeletal Muscle ◽  
Sarcoplasmic Reticulum ◽  
Calcium Release ◽  
Electrical Stimulus ◽  
Final Concentration ◽  
Heavy Fraction ◽  
Frog Skeletal Muscle ◽  
Drug Induced ◽  
Physiological Signal ◽  
Caffeine Contracture

Effects of pretreatment with caffeine on Ca2+ release induced by caffeine, thymol, quercetin, or p-chloromercuriphenylsulfonic acid (pCMPS) from the heavy fraction of sarcoplasmic reticulum (SR) were studied and compared with those effects on caffeine contracture and tetanus tension in single fibers of frog skeletal muscle. Caffeine (1–5 mM) did induce transient Ca2+ release from SR vesicles, but subsequent further addition of caffeine (10 mM, final concentration) induced little Ca2+ release. Ca2+ release induced by thymol, quercetin, or pCMPS was also inhibited by pretreatment with caffeine. In single muscle fibers, pretreatment with caffeine (1–5 mM) partially reduced the contracture induced by 10 mM caffeine. However, tetanus tension was almost maximally induced by electrical stimulus in caffeine-treated fibers. These results indicate that SR, which becomes less sensitive to caffeine, thymol, quercetin, or pCMPS by pretreatment with caffeine, can still respond to a physiological signal transmitted from transverse tubules.Key words: Ca2+ release, sarcoplasmic reticulum, caffeine, tetanus, skeletal muscle.

Role of intracellular calcium and metabolites in low-frequency fatigue of mouse skeletal muscle

1997 ◽  
Vol 272 (2) ◽  
pp. C550-C559 ◽  
Author(s):  
E. R. Chin ◽  
C. D. Balnave ◽  
D. G. Allen
Keyword(s):  
Skeletal Muscle ◽  
Sarcoplasmic Reticulum ◽  
Low Frequency ◽  
Single Muscle ◽  
Low Frequencies ◽  
Time Integral ◽  
Metabolic Component ◽  
Dependent Component ◽  
Low Frequency Fatigue

We have examined the extent to which prolonged reductions in low-frequency force (i.e., low-frequency fatigue) result from increases in intracellular free Ca2+ concentration ([Ca2+]i) and alterations in muscle metabolites. Force and [Ca2+]i were measured in mammalian single muscle fibers in response to short, intermediate, and long series of tetani that elevated the [Ca2+]i-time integral to 5, 17, and 29 microM x s, respectively. Only the intermediate and long series resulted in prolonged (>60 x min) reductions in Ca2+ release and low-frequency fatigue. When fibers recovered from the long series of tetani without glucose, Ca2+ release was reduced to a greater extent and force was reduced at high and low frequencies. These findings indicate that the decrease in sarcoplasmic reticulum Ca2+ release associated with fatigue has at least two components: 1) a metabolic component, which, in the presence of glucose, recovers within 1 h, and 2) a component dependent on the elevation of the [Ca2+]i-time integral, which recovers more slowly. It is this Ca2+-dependent component that is primarily responsible for low-frequency fatigue.

Sign in / Sign up

Export Citation Format

Share Document