The Neurochemistry of Stress: the Chemistry of the Stress Response and Stress Vulnerability

Abstract

Stress, which is an adaptive response of the body, is controlled by the brain. The neuroendocrine system, in particular the hypothalamo–pituitary–adrenal axis (HPAA), is a key player in the stress response. A number of studies have confirmed an association between stress and neurodegenerative and mental diseases and the major role of HPAA dysfunction and cortisol excess in this association. Although many signaling pathways stimulated by HPAA have been discovered, there are many possibilities for switching between these signal transduction pathways and for combining them; numerous factors would determine the involvement of definite mechanisms in the stress response. An aberrant neurochemistry of stress vulnerability and the stress response is the essence of most (if not all) stress-related mental and neurologic diseases, with depressive states being prime example. The neurochemistry of depression is, in fact, the neurochemistry of an abnormal stress response. The stress response may have to be measured; important goals of translational studies include validation of animal models of depression and unification of physiological and biochemical indices of the stress response for comparative analysis of different models and data from depressive patients, as well as elaboration of valid indices of the stress response for patients. For these purposes, it is critical to non-invasively analyze biomaterials such as saliva and hair.