Hypothalamic-Pituitary-Adrenal Axis Effects on Innate and Adaptive Immunity

I. INTRODUCTION The nervous, endocrine, and immune systems secrete and respond to various regulatory molecules including steroids, neuropeptides, cytokines, prostanoids, and neurotransmitters, which provide the molecular basis for neuroendocrine-immune responses during disturbances of homeostasis. The central effectors of these responses include the locus ceruleusnoradrenaline (LC-NA)/autonomic (sympathetic) neurons of the hypothalamus and brain stem and the corticotropin-releasing hormone (CRH)/arginine-vasopressin (AVP) neurons of the paraventricular nucleus of the hypothalamus, which respectively regulate the peripheral activities of the systemic/adrenomedullary sympathetic nervous systems (SNS) and the hypothalamic-pituitary-adrenal (HPA) axis. Activation of the LC-NA/autonomic system and HPA axis results in systemic elevations of catecholamines (CAs) and glucocorticoids (GCs), respectively, that act in concert to maintain a steady state (Chrousos, 1995).