Homeostatic and endocrine responses as the basis for systemic therapy with medical gases: ozone, xenon and molecular hydrogen

Among medical gases, including gases used therapeutically, this review discusses the comparative physiological activity of three gases - ozone (O 3 ), xenon (Xe) and molecular hydrogen (H 2 ), which together form representatives of three types of substances - typical oxidizing, inert, and typical reducing agents. Upon analysis of published and proprietary data, we concluded that these three medical gases can manipulate the neuroendocrine system, by modulating the production or release of hormones via the hypothalamic-pituitary-adrenal, hypothalamic-pituitary-thyroid, hypothalamic-pituitary-gonadal axes, or the gastrointestinal pathway. With repeated administration of the gases over time, these modulations become a predictable consequence of conditioned homeostatic reflexes, resulting in regulation of physiological activity. For example, the regular activation of the unconditioned defense reflex in response to repeated intoxication by ozone leads to the formation of an anticipatory stable conditioned response, which counteracts the toxic action of O 3 . The concept of a Pavlovian conditioned reflex (or hormoligosis) is a brief metaphor for the understanding the therapeutic effect of systemic ozone therapy.