[Catecholamine concentration of the blood of rats after a flight on the Cosmos-936 biosatellite]

The content of epinephrine and norepinephrine was measured in plasma of the rats flown on board the biosatellite Cosmos-936 in the weightlessness state and under artificial gravity. With respect to the norepinephrine content there was no difference between the two flight groups, while its level in the flight rats was higher than in the ground-based controls. The epinephrine content in the flight rats remained essentially unchanged. These data give evidence that a prolonged exposure to weightlessness is not a stressogenic factor as related to the sympathoadrenal system.