Catecholamines, adrenal hormones and stress

Abstract

Different physical, physiological and psychological factors, known as stressors, affect the homeostasis of an organism. The stress system, located in the central nervous system as well as in peripheral organs, mediates the protective stress response. The three principal effector parts of the stress system are hypothalamic-pituitaryadrenocortical, adrenomedullary hormonal system and sympathetic nervous system. Their main respective mediators are cortisol, adrenaline and noradrenaline. The stress response is not the stereotyped one, but depends on the nature of the stressor. The analysis of data from human and animal experiments has shown much closer correlation between the plasma adrenaline and ACTH changes (as a measure of activity of the hypothalamic-pituitary-adrenocortical system) than between adrenaline and noradrenaline responses. While the defense against stressors is of vital importance, inappropriate stress responses, in the direction of deficiency or excess, have been related to a significant number of psychiatric and somatic complaints. It is hoped that at least some of these disorders may be better treated with the anticipated new generation of stress-modifying medications with a central mode of action, such are antagonists of corticotropin (ACTH) releasing hormone (CRH) from hypothalamus.

Različiti fizički, fiziološki i psihološki faktori, poznati kao stresori, utiču na homeostazu organizma. Stresni sistem, smešten u centralnom nervnom sistemu kao i u perifernim organima, posreduje zaštitni stresni odgovor. U tri osnovna efektorna elementa stresnog sistema spadaju hipotalamo-hipofizno-adrenokortikalni, adrenomedularni hormonski i simpatikusni nervni sistem. Glavni medijatori ova tri sistema su, redom, kortizol, adrenalin i noradrenalin. Stresni odgovor nije stereotipan, već zavisi od prirode stresora. Analiza podataka iz eksperimenata sa ljudima i životinjama pokazala je mnogo bližu korelaciju između adrenalina u plazmi i promena ACTH (kao mere aktivnosti hipotalamo-hipofizno-adrenokortikalnog sistema), nego između odgovora adrenalina i noradrenalina. Dok je odbrana od stresora od životnog značaja, neadekvatni stresni odgovori, bilo u smeru nedovoljnosti bilo prekomernosti, povezivani su sa znatnim brojem psihijatrijskih i somatskih tegoba. Postoji nada da bi makar neki od ovih poremećaja mogli biti bolje tretirani sa očekivanom novom generacijom lekova koji centralnim mehanizmom modifikuju stres, kao što su antagonisti kortikotropin (ACTH) oslobađajućeg hormona (CRH) hipotalamusa.