RESUMO
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.
Assuntos
Adaptação Fisiológica , Hemodinâmica , Voo Espacial , Ausência de Peso , Animais , Ritmo Circadiano , Macaca mulatta , Modelos Cardiovasculares , Fatores de TempoRESUMO
Preflight the rhesus-monkey Bion was implanted with sensors and transducers to measure blood pressure and linear flow velocity in the common carotid artery and to compare these parameters with central circulation. At the early flight stage blood pressure increased, blood flow decreased and resistance in the area grew. The last change can be regarded as a compensatory reaction that can provide rapid adaptation of regional circulation to changes in systemic circulation. At later flight stages blood pressure showed distinct circadian oscillations and blood flow, a significant increase when compared to the ground-based 36-hour control study. Regulatory mechanisms of the cardiovascular system changed to the greatest extent on flight day 2. This manifested as a decrease of the amplitude of circadian oscillations of the above circulation parameters. Signs of cardiovascular adaptation to the effects of microgravity were discerned on flight days 3 to 5.
