The hypothalamic-neurohypophysial system regulates the hypothalamic-pituitary-adrenal axis under stress: an old concept revisited.

Mammals respond to challenging situations with characteristic changes in their behaviour as well as in autonomic and neuroendocrine parameters aimed at reinstating their disturbed homeostasis. Among such so-called coping strategies, alterations of the hypothalamic-pituitary-adrenal (HPA) axis play a crucial role. Today it is generally accepted that parvocellular neurones of the hypothalamic paraventricular nucleus control the secretion of corticotropin and corticosterone by synthesising and releasing both the corticotropin-releasing hormone and vasopressin (AVP). Recent evidence supports and embellishes the old hypothesis that AVP and the structurally related neuropeptide, oxytocin, originating from the hypothalamic-neurohypophysial system (HNS) might directly affect HPA axis activity. This review presents data supporting the concept of HNS effects on HPA axis activity and outlines their possible impact on some aspects of behavioural regulation and psychopathology.