[Hemodynamics in monkeys in the initial period of adaptation to weightlessness]

Using pre-implanted electrodes and transducers, arterial pressure and linear blood flow velocity in the common carotid artery of the rhesus-monkey Gordyi were measured during his space flight on a Cosmos biosatellite and ground-based control experiments. As compared to the prelaunch level, blood pressure remained unchanged, blood flow velocity increased significantly and blood flow resistance in the area decreased during the first hours after insertion into orbit. During subsequent flight days mean daily values of blood pressure increased and blood flow returned to the baseline level, although they showed distinct day-night variations. Daily variations of blood flow velocity and its ratio to cardiac output gave evidence that the circulation system of the rhesus-monkey under study rapidly adapted to microgravity conditions.