Neurochemistry of the Stress Response
The neurochemistry of the stress response is now believed to be well understood, although much remains to be discovered about how the components of this system interact with one another, in the brain and throughout the body. In response to a stressor, corticotropin-releasing hormone (CRH) and arginine-vasopressin (AVP) are secreted into the hypophyseal portal system and activate neurons of the paraventricular nuclei (PVN) of the hypothalamus.
The locus ceruleus and other noradrenergic cell groups of the adrenal medulla and pons, collectively known as the LC/NE system, also become active and use brain epinephrine to execute autonomic and neuroendocrine responses, serving as a global alarm system.
The autonomic nervous system provides the rapid response commonly known as the fight-flight response, engaging the sympathetic nervous system and withdrawing the parasympathetic nervous system, thereby enacting cardiovascular, respiratory, gastrointestinal, renal, and endocring changes. The hypothalamic-pituitary-adrenal axis (HPA), is a major part of the neuroendocrine system involving the interactions of the hypothalamus,the pituitary and adrenal glands, is also activated by release of CHR and AVP.
This results in release of adrenocorticotropic hormone (ACTH) from the pituitary into the general bloodstream, which results in secretion of cortisol and other glucocorticords from the adrenal cortex. These corticords involve the whole body in the organism's response to stress and ultimately contribute to the termination of the response via inhibitory feedback.
Stress can significantly affect many of the body's immune systems, as can an individual's perceptions of and reactions to stress. The term psychoneuroimmunology is used to describe the interactions between the mental state, nervous and immune systems, as well as research on the interconnections of these systems.
Reference
The Stress of life, Hans Selye, 1956
