title: Effects of spaceflight on enzyme activities and ultrastructure of fast-type skeletal muscles of rats.
abstract: The activity of succinate dehydrogenase in the medial gastrocnemius muscles of rats was significantly increased following a 2-week spaceflight (p < 0.05). That of phosphofructokinase in plantaris muscles was lowered after the flight (p < 0.05). The overall activities of both enzymes were effectively maintained during the flight. No structural alterations in the mitochondria or other organelles were observed in response to spaceflight. However, disordering of myofilament and central nucleus were often seen in the fast muscle during recovery after landing, but not immediately after landing. These observations indicate that spaceflight increases susceptibility to sarcomere damage and metabolic activity in a specific muscle during reloading.
authors.affiliation: Department of Physiology, St. Marianna University School of Medicine, Kawasaki, Japan.t2yoshi@marianna-u.ac.jp
authors.forename: T
authors.initials: T
authors.lastname: Yoshioka
authors.forename: K
authors.initials: K
authors.lastname: Yamashita-Goto
authors.forename: O
authors.initials: O
authors.lastname: Tanaka
authors.forename: H
authors.initials: H
authors.lastname: Uchida
authors.forename: M
authors.initials: M
authors.lastname: Kimura
authors.forename: K
authors.initials: K
authors.lastname: Fujita
authors.forename: C
authors.initials: C
authors.lastname: Sekiguchi
authors.forename: S
authors.initials: S
authors.lastname: Nagaoka
mesh_terms: D000818:Animals; D008297:Male; D008854:Microscopy, Electron; D008931:Mitochondria, Muscle / Q000648:ultrastructure; D018656:Muscle Fibers, Fast-Twitch / Q000201:enzymology* / Q000648:ultrastructure*; D018482:Muscle, Skeletal / Q000201:enzymology* / Q000648:ultrastructure*; D010732:Phosphofructokinase-1 / Q000032:analysis*; D051381:Rats; D017207:Rats, Sprague-Dawley; D012519:Sarcoplasmic Reticulum / Q000648:ultrastructure; D013026:Space Flight; D013385:Succinate Dehydrogenase / Q000032:analysis*
chemical_list: D013385:Succinate Dehydrogenase; D010732:Phosphofructokinase-1