Deterioration induced by physiological concentration of calcium ions in skinned muscle fibres

Kasuga, Norikatsu; Umazume, Yoshiki

doi:10.1007/bf01833324

Cited by 28 publications

(25 citation statements)

References 22 publications

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“…Calpain inhibitors, however, were not found to prevent either long-duration fatigue in mouse fibers (89) or hypotonic-induced PCD in frog fibers (69). Calpain inhibitors such as leupeptin are quite poor at inhibiting in situ calpain-dependent proteolysis of structural proteins (141), unless used at very high concentration (241,322,451), so it still seems possible that they might play a role in the Ca 2ϩ -dependent uncoupling. It is known, however, that Ca 2ϩ -dependent uncoupling does not involve proteolysis of the DHPRs, RyRs, or another junctional protein, triadin (254).…”

Section: Prolonged Reduction In Ca 2؉ Releasementioning

confidence: 99%

Skeletal Muscle Fatigue: Cellular Mechanisms

Allen¹,

Lamb²,

Westerblad³

2008

Physiological Reviews

1,896

1,876

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Repeated, intense use of muscles leads to a decline in performance known as muscle fatigue. Many muscle properties change during fatigue including the action potential, extracellular and intracellular ions, and many intracellular metabolites. A range of mechanisms have been identified that contribute to the decline of performance. The traditional explanation, accumulation of intracellular lactate and hydrogen ions causing impaired function of the contractile proteins, is probably of limited importance in mammals. Alternative explanations that will be considered are the effects of ionic changes on the action potential, failure of SR Ca2+ release by various mechanisms, and the effects of reactive oxygen species. Many different activities lead to fatigue, and an important challenge is to identify the various mechanisms that contribute under different circumstances. Most of the mechanistic studies of fatigue are on isolated animal tissues, and another major challenge is to use the knowledge generated in these studies to identify the mechanisms of fatigue in intact animals and particularly in human diseases.

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Section: Prolonged Reduction In Ca 2؉ Releasementioning

confidence: 99%

Skeletal Muscle Fatigue: Cellular Mechanisms

Allen¹,

Lamb²,

Westerblad³

2008

Physiological Reviews

1,896

1,876

View full text Add to dashboard Cite

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“…The loss of ␣-actinin (and possibly other cytoskeletal proteins) has been previously proposed to be responsible for reduced rigor or maximum tension. 12,43 Possible consequences of the loss of ␣-actinin and unraveling of the Z line that could be associated with a reduced maximum force include (1) ineffective transmission of the force from the actin-myosin reaction to the ends of the sarcomere and (2) altered interfilament spacing reducing the probability of crossbridges reacting with the thin filament. Whether the degradation of ␣-actinin observed in left ventricular tissue obtained from hearts exposed to 60 minutes of ischemia with no reperfusion is responsible for the loss of ␣-actinin from the myofilament is not clear.…”

Section: Changes In Myofilament Proteins Induced By Ischemia/reperfusionmentioning

confidence: 99%

“…43,50 One such Ca 2ϩ -dependent protease thought to play a role in ischemia is calpain, 7,[12][13][14] which is localized near the Z line. 51 In vitro, ␣-actinin, spectrin, desmin, [52][53][54][55] TnI, and TnT 50 are susceptible to degradation by calpain.…”

Section: Mechanisms For Changes In Myofilament Proteinsmentioning

confidence: 99%

“…15,16 The addition of calpain to skinned muscle fibers causes a decrease in rigor tension with a concurrent loss of a 95-kD protein. 43 This protein is probably ␣-actinin because of its molecular weight and because the addition of calpain to myofibrils or skinned muscle fibers results in the loss of the Z line (which is primarily composed of ␣-actinin 43,55 ). In addition to the loss of ␣-actinin, Gao et al 7 recently showed that addition of calpain to skinned muscle fibers yields the same or similar TnI degradation product as mild ischemia/reperfusion.…”

Section: Mechanisms For Changes In Myofilament Proteinsmentioning

confidence: 99%

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Breakdown and Release of Myofilament Proteins During Ischemia and Ischemia/Reperfusion in Rat Hearts

Eyk

Powers²,

Law³

et al. 1998

Circulation Research

213

156

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Abstract-Our objective in experiments reported here was to identify myofilament proteins of rat hearts either lost or degraded by cardiac ischemia (15-or 60-minute duration) with and without 45 minutes of reperfusion. We correlated these changes with alterations in myofilament sensitivity to Ca 2ϩ and maximum force generation. Protein degradation and loss were assessed by high-performance liquid chromatography, SDS-PAGE, Western blotting analysis, and amino acid sequencing. Compared with nonischemic control hearts, bundles of skinned fibers from hearts subjected to ischemia alone demonstrated a decrease in maximum force generation and an increase in sensitivity to Ca 2ϩ . These changes in function were increased with the duration of the ischemia and with reperfusion. With increasing duration of ischemia, there was an increased loss and degradation of myofibrillar ␣-actinin and troponin I (TnI) at its C-terminus. ␣-Actinin and TnI were most susceptible to ischemia, but with 60 minutes of ischemia/reperfusion, there was also degradation of myosin light chain-1 (MLC1) involving a clip of residues 1 to 19. The MLC1 degradation product was detected in the reperfusion effluent (along with troponin T, tropomyosin, and ␣-actinin) but not in the tissue with 60 minutes of ischemia with no reperfusion. Moreover, with ischemia the following proteins became associated with the myofibrils: GAPDH and proteins of the mitochondrial ATP synthase complex. Our results provide new evidence regarding the mechanism by which ischemia/reperfusion causes myocardial injury and support the hypothesis that an important element in the injury is altered activity and structure of the myofilaments. (Circ Res. 1998;82:261-271.)

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“…(See later section for the temperature used in the X-ray diffraction experiment in Tsukuba.) To keep the fibres unbroken during contraction due to the intrinsic Ca¥-activated protease, a serine protease inhibitor, microbial leupeptin (0·25 mg ml¢; Sigma), was added to the relaxing solution and to some of the rigor solutions (Kasuga & Umazume, 1990). When soleus fibres were to be directly compared with psoas fibres, the comparative experiments were conducted within a period of 10 days under the same conditions using the same solutions.…”

Section: Solution Composition and Temperaturementioning

confidence: 99%

Mechanical study of rat soleus muscle using caged ATP and X‐ray diffraction: high ADP affinity of slow cross‐bridges

Horiuti

Yagi

Takemori

1997

The Journal of Physiology

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The cross‐bridges in slow‐ and fast‐twitch fibres (taken, respectively, from soleus and psoas muscles of rats) were examined in mechanical experiments using caged ATP and X‐ray diffraction, to compare their binding of ATP and ADP. Caged ATP was photolysed in rigor fibres. When ADP was removed from pre‐photolysis fibres, the initial relaxation (±Ca2+) in soleus was as fast as that in psoas fibres, whereas the subsequent contraction (+Ca2+) was slower in soleus than in psoas. The ATPase rate during the steady‐state contraction was also slower in soleus fibres. When ADP was added to pre‐photolysis fibres (±Ca2+), tension developed even in the initial phase, the overall tension development being biphasic. Both initial and late components of the Ca2+‐free contraction were enhanced when ADP was added before photolysis, although pre‐photolysis ADP was not a prerequisite for the late component. The effect of ADP was greater in soleus than in psoas fibres. Static experiments on rigor fibres revealed a higher ADP affinity in soleus fibres. The intensity of the actin layer‐line from ADP rigor soleus fibres decreased rapidly on photorelease of ATP. We conclude that, despite the tight ADP binding of the soleus cross‐bridge, its isometric reaction is not rate limited by the ‘off’ rate of ADP.

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Deterioration induced by physiological concentration of calcium ions in skinned muscle fibres

Cited by 28 publications

References 22 publications

Skeletal Muscle Fatigue: Cellular Mechanisms

Skeletal Muscle Fatigue: Cellular Mechanisms

Breakdown and Release of Myofilament Proteins During Ischemia and Ischemia/Reperfusion in Rat Hearts

Mechanical study of rat soleus muscle using caged ATP and X‐ray diffraction: high ADP affinity of slow cross‐bridges

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