Resposta ao estresse: I. Homeostase e teoria da alostase

Abstract

Over the course of their evolution organisms developed mechanisms to cope with challenging situations originating from both physical and social environments. Tese adaptive mechanisms are coordinated and involve the sequential and/or simultaneous recruitment of different functional systems, mainly neural, endocrine and immune, the so-called stress response. Tey operate to maintain physiological variables at suitable. Tis review aims to discuss the use of the classical homeostasis concept and allostasis, an alternative model, which includes reactive and predictive mechanisms, as well as the different levels of impact of the chronic stressor, resulting in allostatic overload or allostatic failure. Te organizing role of neural, hormonal, immune, systemic and molecular mechanisms, which comprise the allostatic systems underlying the stress response, is also presented.