Activity of the Sympathoadrenal System during Adaptation of the Human Body to Living Inside an Isolated Object

Changes in the activity of the sympathoadrenal systems of three healthy volunteers during their adaptation to living and working inside an isolated facility were studied. The living conditions and the professional activities of the subjects examined simulated those typical of cosmonauts during long-term spaceflight. The activities of the sympathoadrenal and serotonin- and histaminergic systems were assessed through relative rates of synthesis, inactivation, and metabolism. The subjective tolerance to the complex of experimental conditions was evaluated with a feeling–activity–mood test. It was shown that, while a human lives and works inside an isolated facility, adaptive changes in some parameters of the sympathoadrenal and histaminergic systems proceed through specific temporal phases. Among the rates of synthesis, inactivation, and metabolism, the most significant phase-related changes were observed in parameters of the metabolic activity. Apparently, the metabolic activity of the liver and other tissues affecting the blood levels of catecholamines and other biogenic amines is a leading mechanism of those phase-related changes in transmitter systems that are evident during human adaptation to complicated living conditions. For many of the metabolic parameters tested, rates of change were either independent of other experimental conditions or showed a less significant dependence on conditions than on phase-related factors.