Role of genetic peculiarities in resistance of the body to detrimental impacts and protective effects of adaptation

: Review summarizes results of studies performed in two rat strains, August and Wistar, on the role of genetically determined peculiarities of the stress system (system managing the stress response to detrimental impacts) and of stress-limiting systems (systems restricting activation of the stress system and, therefore, detrimental effects of the stress reaction) in the mechanism of resistance to detrimental factors and the effectiveness of adaptation defence against these factors. A concept is substantiated on the dependence of resistance to stress impacts and factors possessing a distinct stress component (emotions, detrimental impacts, myocardial infarction, etc.) on genetically predetermined, innate peculiarities of stress-limiting systems. This concept also implies a dependence of protective effects of adaptation to environmental factors on genetically determined changes in activities of stress-limiting systems during adaptation. Higher activity of these systems (August rats) is associated with higher resistance to detrimental factors whereas lower innate activity of these systems (Wistar rats) is associated with lower resistance. In the process of adaptation to environmental factors, the resistance decreases in rats with higher innate resistance (August rats); in animals with lower resistance (Wistar rats), adaptation effectively increases resistance to damages. The key factor is changes in activities of stress-limiting systems during development of adaptation. In rats with higher innate activity of these systems (August rats), adaptation reduces ("wearing out") of this activity in combination with declining resistance to damage in adapted rats. In rats with lower innate resistance of stress-limiting systems (Wistar rats), adaptation increases both the activity of these systems and the resistance to detrimental factors.