Abstract: Ca2+ triggers the contraction of muscle and participates in the regulation of muscle cells′ activities. The maintenance of calcium homeostasis plays an important role in the muscle contractile function. The imbalance of calcium homeostasis, and the transition of myosin phenotype and the decrease of skeletal muscle contractile function are closely related to the simulated weightlessness. The relationship between calcium homeostasis and muscle atrophy under simulated weightlessness and the possible mechanism of calcium homeostasis are reviewed in this article.

Key words: simulated weightlessness, Ca2+, muscle atrophy