Influence of temperature and external Ca2+ concentration upon dantrolene action on excitation–contraction coupling in frog skeletal muscle

1981 ◽  
Vol 59 (4) ◽  
pp. 358-363 ◽  
Author(s):  
Toshiharu Oba
Keyword(s):  
Skeletal Muscle ◽  
Mechanism Of Action ◽  
Binding Sites ◽  
Threshold Current ◽  
Frog Skeletal Muscle ◽  
Temperature Dependent ◽  
Influence Of Temperature ◽  
Contraction Coupling ◽  
Mechanical Responses ◽  
Intracellular Stimulation

Effects of dantrolene (DAN) on electrical and mechanical responses in frog skeletal muscle were studied at various Ca2+ concentrations and temperatures to elucidate the mechanism of action of DAN. The following results were obtained. (a) Twitch tension of a DAN-injected fiber, elicited by intracellular stimulation, increased transiently and then decreased whereas extracellular DAN always depressed the tension. (b) Lowering the external Ca2+ concentration resulted in the potentiation of twitch tension. The addition of DAN, however, reduced the tension significantly (p < 0.05). (c) Extracellular DAN caused a transient reduction and subsequent elevation of the threshold current; however intracellular DAN caused only elevation of threshold. (d) DAN prevented the slow depolarization of the membrane in low Ca2+ medium. (e) These effects of the drug were temperature dependent, the effect being more pronounced at higher temperatures. These findings suggest that DAN may manifest its effects by replacement of Ca2+ from its binding sites on the membrane and that this occupation of the Ca2+ sites by DAN is temperature dependent.

Erratum: Influence of temperature and external Ca2+ concentration upon dantrolene action on excitation–contraction coupling in frog skeletal muscle

1981 ◽  
Vol 59 (6) ◽  
pp. 607-612
Author(s):  
Toshiharu Oba
Keyword(s):  
Skeletal Muscle ◽  
Mechanism Of Action ◽  
Binding Sites ◽  
Threshold Current ◽  
Frog Skeletal Muscle ◽  
Temperature Dependent ◽  
Influence Of Temperature ◽  
Contraction Coupling ◽  
Mechanical Responses ◽  
Intracellular Stimulation

Effects of dantrolene (DAN) on electrical and mechanical responses in frog skeletal muscle were studied at various Ca2+ concentrations and temperatures to elucidate the mechanism of action of DAN. The following results were obtained. (a) Twitch tension of a DAN-injected fiber, elicited by intracellular stimulation, increased transiently and then decreased whereas extracellular DAN always depressed the tension. (b) Lowering the external Ca2+ concentration resulted in the potentiation of twitch tension. The addition of DAN, however, reduced the tension significantly (p < 0.05). (c) Extracellular DAN caused a transient reduction and subsequent elevation of the threshold current; however intracellular DAN caused only elevation of threshold. (d) DAN prevented the slow depolarization of the membrane in low Ca2+ medium. (e) These effects of the drug were temperature dependent, the effect being more pronounced at higher temperatures. These findings suggest that DAN may manifest its effects by replacement of Ca2+ from its binding sites on the membrane and that this occupation of the Ca2+ sites by DAN is temperature dependent.

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.

The Effect of Lanthanum on Excitation–Contraction Coupling in Frog Skeletal Muscle

1974 ◽  
Vol 52 (6) ◽  
pp. 1126-1135 ◽  
Author(s):  
D. J. Parry ◽  
A. Kover ◽  
G. B. Frank
Keyword(s):  
Skeletal Muscle ◽  
Action Potential ◽  
Muscle Membrane ◽  
Frog Skeletal Muscle ◽  
Tension Development ◽  
Excitation Contraction Coupling ◽  
Contraction Coupling ◽  
Reduced Rate ◽  
Caffeine Contractures

Exposure of frog toe muscles to 1 mM La3+ results in a decrease in amplitude and rate of tension development of potassium contractures and twitches. At this concentration La3+ also inhibits the uptake of calcium, both in the resting condition and during stimulation. Caffeine contractures are unaffected even after a 5-min pre-exposure to La3+. The depolarization induced by various concentrations of K+ is reduced by about 10 mV as is the amplitude of the action potential. The rate of rise of the action potential is reduced by about 40% after 1 min in La3+ Ringer. Neither the decreased amplitude nor the reduced rate of depolarization is considered to be sufficient to explain the inhibition of tension development. It is suggested that La3+ partially uncouples excitation from contraction by preventing the release of a trigger-Ca2+ fraction from some site on the muscle membrane. This fraction normally plays a role in excitation–contraction coupling, although some tension may still be developed in the absence of a trigger-Ca2+ influx.

Electromechanical Coupling II. The Effect of Perchlorate Upon Excitation-Contraction Coupling in Frog Skeletal Muscle Fibres

1982 ◽  
Vol 37 (7-8) ◽  
pp. 707-708
Author(s):  
Michael Gomolla ◽  
Gernot Gottschalk ◽  
Hans-Christoph Lüttgau
Keyword(s):  
Skeletal Muscle ◽  
Electromechanical Coupling ◽  
Muscle Fibres ◽  
Frog Skeletal Muscle ◽  
Large Shift ◽  
Excitation Contraction Coupling ◽  
Contraction Coupling ◽  
Inactivation Process ◽  
Skeletal Muscle Fibres ◽  
Kinetics Of

Abstract In single skeletal muscle Fibres perchlorate causes a large shift of the potential dependence of contraction activation to more negative potentials without a corresponding alteration in the kinetics of the inactivation process.

Studies on Ca2+−Mg2+ Binding Sites of Frog Skeletal Muscle Myosin1

1979 ◽  
Vol 86 (3) ◽  
pp. 829-832 ◽  
Author(s):  
Joan WIKMAN-COFFELT ◽  
Sudhir SRIVASTAVA
Keyword(s):  
Skeletal Muscle ◽  
Binding Sites ◽  
Frog Skeletal Muscle

TETRAETHYLAMMONIUM-INDUCED CONTRACTIONS OF FROG'S SKELETAL MUSCLE: III. MECHANISM OF ACTION BY CALCIUM RELEASE

1967 ◽  
Vol 45 (5) ◽  
pp. 845-855 ◽  
Author(s):  
G. Beaulieu ◽  
G. B. Frank
Keyword(s):  
Skeletal Muscle ◽  
Mechanism Of Action ◽  
Binding Sites ◽  
Neuromuscular Transmission ◽  
Calcium Concentration ◽  
Calcium Release ◽  
Sartorius Muscle ◽  
Free Solution ◽  
Muscle Twitching ◽  
Solution Bathing

The effects of changes in the extracellular calcium concentration on the muscle 'twitching' response induced by tetraethylammonium of the frog's sartorius muscle were investigated. Decreasing the calcium concentration of a solution bathing the muscle increased the sensitivity of the muscle to TEA stimulation. However, with a sufficient calcium reduction (to 0.108 mM in most preparations) the muscles became completely insensitive to TEA stimulation. In contrast, calcium reduction resulted only in an increased muscle sensitivity to carbachol stimulation. Increasing the calcium concentration greatly decreased TEA sensitivity, and at 2.16 mM calcium a TEA-induced muscle 'twitching' response no longer could be produced. At this calcium concentration carbachol sensitivity was reduced but not eliminated and neuromuscular transmission was essentially unmodified. In studies with the toe muscle, it was found that TEA could restore the potassium-induced contracture that had been eliminated by soaking the muscle in a calcium-free solution. This effect of TEA was dependent upon the presence of a store of bound calcium in the muscle. These results are consistent with the hypothesis that TEA acts by releasing calcium from binding sites on the nerve endings, leading to an increased excitability and instability of these structures and resulting in the muscle twitching response. Other effects of TEA similar to those of increases in calcium are due to an increased level of ionized calcium at nerve and muscle membranes which also results from the release by TEA of calcium from membrane sites.

Mechanism of action of 2, 3-butanedione 2-monoxime on contraction of frog skeletal muscle fibres

1988 ◽  
Vol 9 (2) ◽  
pp. 156-164 ◽  
Author(s):  
K. Horiuti ◽  
H. Higuchi ◽  
Y. Umazume ◽  
M. Konishi ◽  
O. Okazaki ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Mechanism Of Action ◽  
Muscle Fibres ◽  
Frog Skeletal Muscle ◽  
Skeletal Muscle Fibres
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