[Characteristics of the microcirculatory bed of the gastrocnemius muscle of rats under conditions of weightlessness].

Quantitative histological investigations of capillaries in the gastrocnemius muscle of rats after 18.5 days on board the artificial satellite "Cosmos-936" have demonstrated that the number of functioning capillaries decrease by about 30% under conditions of weightlessness. Decrease in the number of functioning capillaries in the gastrocnemius muscle is also observed in animals subjected to artificial gravitation (acceleration 1 g) during the flight. The main role in lowered blood supply of the muscles is supposed to play the lack of kinetic but not static loading on the muscles.