Changes of intracellular electrolyte contents in rat skeletal muscle during body suspension

Nagaoka, Ryoji; Mizuno, Masaharu; Yamashita, Shinji; Akaike, Norio

doi:10.1016/0300-9629(94)00175-s

Cited by 2 publications

(1 citation statement)

References 23 publications

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“…However, most of the studies have been concentrated on weightlessness-induced changes on extrafusal muscle fibers, not on muscle spindle [4][5][6] . It cannot be ignored that in relation to extrafusal muscle fibers, muscle spindle is an important receptor in skeletal muscle to detect any changes in skeletal muscle fiber length, tension, movement direction, speed and speed changes, and the rate of change [7] .…”

Section: Role Of Muscle Spindle In Weightlessnessinduced Amyotrophiamentioning

confidence: 99%

肌梭在失重性肌萎缩与肌肉痛中的作用

2009

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To date, the medium and long-term space flight is urgent in need and has become a major task of our manned space flight program. There is no doubt that medium and long-term space flight has serious damaging impact upon human physiological systems. For instance, atrophy of the lower limb anti-gravity muscle can be induced during the space flight. Muscle atrophy significantly affects the flight of astronauts in space. Most importantly, it influences the precise manipulation of the astronauts and their response capacity to emergencies on returning to the atmosphere from space. Muscle atrophy caused by weightlessness may also seriously disrupt the normal life and work of the astronauts during the re-adaptation period. Here we summarize the corresponding research concentrating on weightlessness-induced changes of muscular structure and function. By combining research on muscle pain, which is a common clinical pain disease, we further provide a hypothesis concerning a dynamic feedback model of "weightlessness condition right triple arrow muscular atrophy <--> muscle pain". This may be useful to explore the neural mechanisms underlying the occurrence and development of muscular atrophy and muscle pain, through the key study of muscle spindle, and furthermore provide more effective therapy for clinical treatment.

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Section: Role Of Muscle Spindle In Weightlessnessinduced Amyotrophiamentioning

confidence: 99%

肌梭在失重性肌萎缩与肌肉痛中的作用

2009

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Dynamics and Consequences of Potassium Shifts in Skeletal Muscle and Heart During Exercise

Sejersted

Sjøgaard

2000

Physiological Reviews

425

433

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Since it became clear that K(+) shifts with exercise are extensive and can cause more than a doubling of the extracellular [K(+)] ([K(+)](s)) as reviewed here, it has been suggested that these shifts may cause fatigue through the effect on muscle excitability and action potentials (AP). The cause of the K(+) shifts is a transient or long-lasting mismatch between outward repolarizing K(+) currents and K(+) influx carried by the Na(+)-K(+) pump. Several factors modify the effect of raised [K(+)](s) during exercise on membrane potential (E(m)) and force production. 1) Membrane conductance to K(+) is variable and controlled by various K(+) channels. Low relative K(+) conductance will reduce the contribution of [K(+)](s) to the E(m). In addition, high Cl(-) conductance may stabilize the E(m) during brief periods of large K(+) shifts. 2) The Na(+)-K(+) pump contributes with a hyperpolarizing current. 3) Cell swelling accompanies muscle contractions especially in fast-twitch muscle, although little in the heart. This will contribute considerably to the lowering of intracellular [K(+)] ([K(+)](c)) and will attenuate the exercise-induced rise of intracellular [Na(+)] ([Na(+)](c)). 4) The rise of [Na(+)](c) is sufficient to activate the Na(+)-K(+) pump to completely compensate increased K(+) release in the heart, yet not in skeletal muscle. In skeletal muscle there is strong evidence for control of pump activity not only through hormones, but through a hitherto unidentified mechanism. 5) Ionic shifts within the skeletal muscle t tubules and in the heart in extracellular clefts may markedly affect excitation-contraction coupling. 6) Age and state of training together with nutritional state modify muscle K(+) content and the abundance of Na(+)-K(+) pumps. We conclude that despite modifying factors coming into play during muscle activity, the K(+) shifts with high-intensity exercise may contribute substantially to fatigue in skeletal muscle, whereas in the heart, except during ischemia, the K(+) balance is controlled much more effectively.

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Changes of intracellular electrolyte contents in rat skeletal muscle during body suspension

Cited by 2 publications

References 23 publications

肌梭在失重性肌萎缩与肌肉痛中的作用

肌梭在失重性肌萎缩与肌肉痛中的作用

Dynamics and Consequences of Potassium Shifts in Skeletal Muscle and Heart During Exercise

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