“…In particular, chronic stress can lead to potentiated basal ACTH and/or corticosterone secretion, adrenal hypertrophy and elevated PVN CRH and AVP mRNA and protein expression (Hauger et al, 1988;Herman et al, 1995;Kiss and Aguilera, 1993;Ulrich-Lai et al, 2006b). Chronic exposure to homotypic stressors typically engender some degree of HPA axis habituation (Dhabhar et al, 1997;Odio and Brodish, 1989;Pitman et al, 1988;Viau and Sawchenko, 2002). However, despite the presence of an enhanced glucocorticoid feedback signals, HPA responses to new stressors are either maintained or augmented following chronic stress a process known as stress facilitation (Armario et al, 1985;Bhatnagar and Dallman, 1998;Bhatnagar and Vining, 2003;Dallman et al, 1992;Hauger et al, 1990;Kiss and Aguilera, 1993;Ostrander et al, 2006).…”