title: Responses of skeletal muscles to gravitational unloading and/or reloading.
abstract: Adaptation of morphological, metabolic, and contractile properties of skeletal muscles to inhibition of antigravity activities by exposure to a microgravity environment or by simulation models, such as chronic bedrest in humans or hindlimb suspension in rodents, has been well reported. Such physiological adaptations are generally detrimental in daily life on earth. Since the development of suitable countermeasure(s) is essential to prevent or inhibit these adaptations, effects of neural, mechanical, and metabolic factors on these properties in both humans and animals were reviewed. Special attention was paid to the roles of the motoneurons (both efferent and afferent neurograms) and electromyogram activities as the neural factors, force development, and/or length of sarcomeres as the mechanical factors and mitochondrial bioenergetics as the metabolic factors.
authors: Space Biomedical Research Office, Japan Aerospace Exploration Agency, Tsukuba, Ibaraki, 305-8505, Japan.
authors: Takashi
authors: T
authors: Ohira
authors: Fuminori
authors: F
authors: Kawano
authors: Tomotaka
authors: T
authors: Ohira
authors: Katsumasa
authors: K
authors: Goto
authors: Yoshinobu
authors: Y
authors: Ohira
mesh_terms: D000222:Adaptation, Physiological; D000818:Animals; D001510:Bed Rest / Q000009:adverse effects; D001696:Biomechanical Phenomena; D004734:Energy Metabolism; D006112:Gravitation; D019417:Hindlimb Suspension / Q000502:physiology; D006801:Humans; D008931:Mitochondria, Muscle / Q000378:metabolism; D009046:Motor Neurons / Q000502:physiology; D009119:Muscle Contraction / Q000502:physiology; D018482:Muscle, Skeletal / Q000502:physiology*; D012518:Sarcomeres / Q000502:physiology; D013026:Space Flight; D014893:Weightlessness; D018474:Weightlessness Simulation