These neurons terminate on cardiovascular and visceral organs or on the adrenal medulla, and stimulate the release of adrenaline from the adrenal medulla and noradrenaline from sympathetic

nerve fibers. Consequences of ANS activation by stress include changes in heart rate and vasoconstriction. In the HPA axis, stress activates neurons in the paraventricular nucleus (PVN) of the hypothalamus LY2109761 in vivo to secrete corticotropin releasing factor (CRF) and arginine vasopressin (AVP) into the portal circulation via the median eminence, which in turn stimulate the anterior pituitary gland to release adrenocorticotropic hormone (ACTH). ACTH activates glucocorticoid synthesis and release from the adrenal cortex, which functions primarily to mobilize energy stores during stress. There is ample cross-talk between the ANS and the HPA axis—the adrenal cortex receives innervation from the sympathetic nervous system, regulating glucocorticoid release, and glucocorticoids mediate ANS-dependent

stress responses including vasoconstriction. Modulation of these systems has been noted in cases of human resilience to MDD and post-traumatic stress disorder (PTSD), although results have been largely correlative (Russo et al., 2012). High dose glucocorticoid administration following Selleckchem Regorafenib traumatic stress exposure has emerged as a potential treatment for individuals vulnerable to PTSD, perhaps working by controlling hyperactive fear response and fear memory consolidation (Kearns et al., 2012). This strategy has yielded positive results in critically ill hospital patients and combat-exposed veterans (Schelling et al., 2006 and Suris et al., 2010). Additionally, dehydroepiandrosterone Parvulin (DHEA) and neuropeptide Y (NPY) have emerged as potential pro-resilience biomarkers in humans. DHEA is released from the adrenal cortex with cortisol in response to stress and can counter the effects of glucocorticoids (Yehuda et al., 2006a). In combat-exposed veterans, both DHEA level and DHEA/cortisol ratio correlate negatively with PTSD symptom severity, suggesting that DHEA may serve a protective role in situations of extreme stress. NPY is co-released with noradrenaline from sympathetic nerves and

has been shown to correlate positively with interrogation performance and negatively with dissociative symptoms in soldiers undergoing a U.S. Army survival training course (Morgan et al., 2000b). The Hypothalamic Pituitary Gonadal (HPG) axis shares numerous component structures and neural circuitry with the HPA axis, and accordingly, reproductive hormones serve a prominent role in susceptibility and resilience to stress. Mood disorders including MDD and anxiety are about two times more prevalent in adult women than men, a sex difference that emerges in puberty and persists until menopause, suggesting a role for sex hormone fluctuations and activating effects of gonadal hormones on neural circuitry (Deecher et al., 2008, Holden, 2005 and Epperson et al., 2014).