[Cerebral cortical blood flow during parabolic maneuvers].

Cerebral cortical blood flow (CBF) was measured in 6 rabbits during parabolic flight maneuvers (20 s of weightlessness). During the first seconds of weightlessness, CBF increased up to 100% when compared with CBF at 1 G. Since this transient increase (5 s) was not modified when propranolol or pentobarbital was given to the animals, one can hypothesize that it was not related to stress.