These hormones act on organs in a slower, longer lasting response when compared to the sympathetic nervous system. Cortisol is a glucocorticoid. It is secreted by the adrenal gland as part of the hypothalamic-pituitary-adrenal axis (HPA axis), particularly in response to stress. Within psychiatric disorders, depression and generalized anxiety disorder are the most common stress related diseases. These illnesses have some links to dysfunctions of neurotransmitters and neurohormones, including the hypothalamo–pituitary– adrenal (HPA) axis (Laurence Lanfumey a,b, *, Raymond Mongeau a,b , Charles Cohen-Salmon c,d , Michel Hamon a,b, 2008). The purpose of the stress response is to maintain homeostasis (Sapolsky, 2003), this includes a succession of physiological changes such as the activation of the endocrine system and cardiovascular changes. When prolonged and sustained stress exceeds the body capacity to maintain homeostasis that stress can have psychopathological …show more content…
There is evidence that chronic elevation of corticosteroid levels leads to neurodegeneration or suppressed neurogenesis within the hippocampus (Magarinos AM, McEwen BS, Flügge G, Fuchs E 1996 Chronic psychosocial stress causes apical dendritic atrophy of hippocampal CA3 pyramidal neurons in subordinate tree shrews. J Neurosci 16:3534–3540 Medline). Studies by Margarinos et al. (1996) showed that repeated exposure to a daily psychosocial stressor in male tree shrews resulted in apical dendritic atrophy of hippocampal CA3 pyramidal neurons. The stressed group of shrews showed a decreased number of branch points and total dendritic length as compared with controls. These results suggested that the exposure to the psychological stressor induced specific structural changes in hippocampal neurons of the subjects. The hippocampus contains high levels of corticosteroid receptors which makes the structure critical in the feedback control of HPA axis activity. Corticosteroids within the hippocampus also have an affect on neuron survival, cell proliferation, gene expression, neuronal excitability, as well as neuronal networks and underlying mechanisms that include learning and memory (kim and diamond,