Potentiation of the halothane-cooling contractures of mammalian muscles by denervation

1990 ◽  
Vol 68 (9) ◽  
pp. 1207-1213 ◽  
Author(s):  
Margarete M. Trachez ◽  
R. Takashi Sudo ◽  
G. Suarez-Kurtz
Keyword(s):  
Skeletal Muscle ◽  
Sarcoplasmic Reticulum ◽  
Soleus Muscle ◽  
Extensor Digitorum Longus ◽  
Extensor Digitorum ◽  
Tension Development ◽  
Excitation Contraction Coupling ◽  
Contraction Coupling ◽  
Denervated Muscles

Denervation potentiated the cooling-induced contractures and the halothane-cooling contractures of isolated extensor digitorum longus and soleus muscles of the mouse. These effects were more striking in extensor digitorum longus than in soleus muscles. Significant increases in the peak amplitudes of the halothane-cooling contractures of both muscles and of the cooling contractures of soleus muscle were observed within 2 and 7 days of denervation. The potentiation of the contractures persisted for 90 days, the period of this study. Denervation (>2 days) endowed extensor digitorum longus with the ability to generate cooling contractures in the absence of halothane. The rate of tension development of cooling-induced contractures in the absence or presence of halothane was significantly greater in denervated (2–90 days) than in innervated muscles. Denervation also reduced the effectiveness of procaine in inhibiting the halothane-cooling contractures. It is proposed that the potentiation of cooling-induced contractures in denervated muscles results primarily from an increase in the rate of efflux and in the quantity of Ca2+ released from the sarcoplasmic reticulum, upon cooling and (or) when challenged with halothane.Key words: denervation, excitation–contraction coupling, halothane, cooling-induced contractures, skeletal muscle.

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.

Lactate inhibits Ca2+-activated Ca2+-channel activity from skeletal muscle sarcoplasmic reticulum

1997 ◽  
Vol 82 (2) ◽  
pp. 447-452 ◽  
Author(s):  
Terence G. Favero ◽  
, Anthony C. Zable ◽  
, David Colter ◽  
Jonathan J. Abramson
Keyword(s):  
Skeletal Muscle ◽  
Sarcoplasmic Reticulum ◽  
Single Channel ◽  
Channel Activity ◽  
Release Channel ◽  
Muscle Lactate ◽  
Tension Development ◽  
Contraction Coupling ◽  
Single Channel Activity ◽  
High Concentrations

Favero, Terence G., Anthony C. Zable, David Colter, and Jonathan J. Abramson. Lactate inhibits Ca2+-activated Ca2+-channel activity from skeletal muscle sarcoplasmic reticulum. J. Appl. Physiol. 82(2): 447–452, 1997.—Sarcoplasmic reticulum (SR) Ca2+-release channel function is modified by ligands that are generated during about of exercise. We have examined the effects of lactate on Ca2+- and caffeine-stimulated Ca2+ release, [3H]ryanodine binding, and single Ca2+-release channel activity of SR isolated from rabbit white skeletal muscle. Lactate, at concentrations from 10 to 30 mM, inhibited Ca2+- and caffeine-stimulated [3H]ryanodine binding to and inhibited Ca2+- and caffeine-stimulated Ca2+ release from SR vesicles. Lactate also inhibited caffeine activation of single-channel activity in bilayer reconstitution experiments. These findings suggest that intense muscle activity, which generates high concentrations of lactate, will disrupt excitation-contraction coupling. This may lead to decreases in Ca2+ transients promoting a decline in tension development and contribute to muscle fatigue.

Calmodulin and Excitation-Contraction Coupling

Physiology ◽  
2000 ◽  
Vol 15 (6) ◽  
pp. 281-284 ◽  
Author(s):  
Susan L. Hamilton ◽  
Irina Serysheva ◽  
Gale M. Strasburg
Keyword(s):  
Skeletal Muscle ◽  
Ion Channels ◽  
Sarcoplasmic Reticulum ◽  
Release Channel ◽  
Excitation Contraction Coupling ◽  
Transverse Tubule ◽  
Contraction Coupling ◽  
Voltage Dependent ◽  
Important Regulator ◽  
Precise Role

Excitation-contraction coupling in cardiac and skeletal muscle involves the transverse-tubule voltage-dependent Ca2+ channel and the sarcoplasmic reticulum Ca2+ release channel. Both of these ion channels bind and are modulated by calmodulin in both its Ca2+-bound and Ca2+-free forms. Calmodulin is, therefore, potentially an important regulator of excitation-contraction coupling. Its precise role, however, has not yet been defined.

scholarly journals Computational assessment of transport distances in living skeletal muscle fibers studied in situ

2020 ◽  
Author(s):  
Kenth-Arne Hansson ◽  
Andreas Våvang Solbrå ◽  
Kristian Gundersen ◽  
Jo Christiansen Bruusgaard
Keyword(s):  
Skeletal Muscle ◽  
Soleus Muscle ◽  
Extensor Digitorum Longus ◽  
Transportation Network ◽  
Muscle Fibers ◽  
Extensor Digitorum ◽  
Nuclear Density ◽  
Skeletal Muscle Fibers ◽  
Longus Muscle

AbstractTransport distances in skeletal muscle fibers are mitigated by these cells having multiple nuclei. We have studied mouse living slow (soleus) and fast (extensor digitorum longus) muscle fibers in situ and determined cellular dimensions and the positions of all the nuclei within fiber segments. We modelled the effect of placing nuclei optimally and randomly using the nuclei as the origin of a transportation network. It appeared that an equidistant positioning of nuclei minimizes transport distances along the surface for both muscles. In the soleus muscle however, which were richer in nuclei, positioning of nuclei to reduce transport distances to the cytoplasm were of less importance, and these fibers exhibit a pattern not statistically different from a random positioning of nuclei. Together, these results highlight the importance of spatially distribute nuclei to minimize transport distances to the surface when nuclear density is low, while it appears that the distribution are of less importance at higher nuclear densities.

scholarly journals Immunohistochemical localization of two proteinases in skeletal muscle.

1983 ◽  
Vol 31 (6) ◽  
pp. 827-830 ◽  
Author(s):  
W T Stauber ◽  
V Fritz ◽  
B Dahlmann ◽  
H Reinauer
Keyword(s):  
Skeletal Muscle ◽  
Mast Cells ◽  
Soleus Muscle ◽  
Extensor Digitorum Longus ◽  
Muscle Fibers ◽  
Immunohistochemical Localization ◽  
Extensor Digitorum ◽  
The Other ◽  
Other Hand

Immunohistochemical localizations of cytosolic and myofibrillar proteinases revealed a different myofiber locale for each enzyme in the rat. Although the cytosolic proteinase was most pronounced in mast cells within soleus and extensor digitorum longus (EDL) muscles, certain fibers of the EDL were also positive. The myofibrillar proteinase, on the other hand, appeared to be present in interstitial spaces between muscle fibers in the EDL but conversely present in some fibers of the soleus muscle.

Effect of clenbuterol on sarcoplasmic reticulum function in single skinned mammalian skeletal muscle fibers

1998 ◽  
Vol 274 (6) ◽  
pp. C1718-C1726 ◽  
Author(s):  
Anthony J. Bakker ◽  
Stewart I. Head ◽  
Anthony C. Wareham ◽  
D. George Stephenson
Keyword(s):  
Skeletal Muscle ◽  
Sarcoplasmic Reticulum ◽  
Rattus Norvegicus ◽  
Extensor Digitorum Longus ◽  
Muscle Fibers ◽  
Mammalian Skeletal Muscle ◽  
Direct Effects ◽  
Contraction Coupling ◽  
Slow Twitch

We examined the effect of the β2-agonist clenbuterol (50 μM) on depolarization-induced force responses and sarcoplasmic reticulum (SR) function in muscle fibers of the rat ( Rattus norvegicus; killed by halothane overdose) that had been mechanically skinned, rendering the β2-agonist pathway inoperable. Clenbuterol decreased the peak of depolarization-induced force responses in the extensor digitorum longus (EDL) and soleus fibers to 77.2 ± 9.0 and 55.6 ± 5.4%, respectively, of controls. The soleus fibers did not recover. Clenbuterol significantly and reversibly reduced SR Ca2+loading in EDL and soleus fibers to 81.5 ± 2.8 and 78.7 ± 4.0%, respectively, of controls. Clenbuterol also produced an ∼25% increase in passive leak of Ca2+ from the SR of the EDL and soleus fibers. These results indicate that clenbuterol has direct effects on fast- and slow-twitch skeletal muscle, in the absence of the β2-agonist pathway. The increased Ca2+ leak in the triad region may lead to excitation-contraction coupling damage in the soleus fibers and could also contribute to the anabolic effect of clenbuterol in vivo.

Effect of cyclopiazonic acid on contractile responses in slow and fast bundles of cremaster skeletal muscle from the ferret

1994 ◽  
Vol 72 (8) ◽  
pp. 833-840 ◽  
Author(s):  
Corinne Huchet ◽  
Claude Léoty
Keyword(s):  
Skeletal Muscle ◽  
Sarcoplasmic Reticulum ◽  
Extensor Digitorum Longus ◽  
Cyclopiazonic Acid ◽  
Extensor Digitorum ◽  
Skinned Fibers ◽  
Contractile Apparatus ◽  
Slow Twitch ◽  
Slow Twitch Fibers ◽  
Dose Dependent

The effects of cyclopiazonic acid (CPA) on twitch force, calcium (Ca2+) uptake and release by the sarcoplasmic reticulum (SR), and Ca2+ sensitivity of contractile apparatus were studied using intact and chemically skinned cremaster fibers and compared with those on the extensor digitorum longus and soleus. In cremaster muscles treated with CPA (0.5–5 μM) a potentiation of the twitch was observed, associated with an increase in time to peak and in time of relaxation. In Triton-skinned fibers, CPA, at concentrations less than 10 μM, exerted no significant effect on the contractile apparatus of either slow- or fast-twitch fibers. In slow-twitch fibers, a dose-dependent increase in Ca2+ sensitivity was associated with a decrease in maximal tension, at CPA concentrations > 10 μM. In saponin-skinned fibers, during the uptake phase, CPA at > 10 μM induced a dose-dependent decrease in caffeine contracture. The possibility of an action on the SR Ca2+ release channel was excluded by testing the effect of CPA during the releasing phase. The enhancing effect of CPA (0.5 – 5 μM) on mechanical activity could be explained by an inhibition of the SR Ca2+ ATPase in skeletal muscle cells without an effect on the contractile proteins. Our results strongly suggest that CPA (< 10 μM) has a highly specific effect on the SR Ca2+ pump in the fast- and slow-twitch fibers and therefore could be a good tool to study the mechanisms of Ca2+ regulation in skeletal muscles. Furthermore, the study of the SR properties, using CPA, has shown no significant differences in the SR function of ferret cremaster fibers in comparison with extensor digitorum longus and soleus muscles.Key words: caffeine, skinned fiber, sarcoplasmic reticulum.

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