[Stress and microgravity]

Abstract

There is an opinion that microgravity does not stress organism of mammalians, humans are not excluded, first of all because of the lack of evidence of activation of the cortical and medullary substance in the adrenals. The article brings forward an argument for the stressful nature of microgravity. Guided by the theoretical assumptions and by factual data, the author makes a supposition that microgravity suppresses stress-reactions implemented by the hypothalamo-pituitary-adrenal and sympathoadrenal systems, for the reason that these reactions have same catabolic features as the specific effects of microgravity. In other words, we should not wave off the idea that to prevent muscular atrophy in microgravity, organism triggers mechanisms of blocking the classic paths of the non-specific stress-reaction involving the glucocorticoid and catecholamine functions of the adrenals. From this standpoint, microgravity modifies markedly the overall pattern of stress reaction, which does not overthrow the concept about the non-specific character of stress and microgravity as a stress-factor.