Interactions of orphanin FQ/nociceptin (OFQ/N) system with immune system factors and hypothalamic–pituitary–adrenal (HPA) axis

Background Brain–immune system interactions and neurohormonal changes which are induced by psychophysiological factors are growing areas of scientific interest. Central (CNS) and autonomic nervous-endocrine-immune system pathways are connected with a number of behavioral and physiological factors which may be linked to disease susceptibility and progression. Methods In this paper, influence of orphanin FQ/nociceptin receptor (OFQ/N) on the hypothalamic–pituitary–adrenal (HPA) axis and their influence on the immunological system was reviewed. Conclusions The neuroendocrine system, in particular the hypothalamic–pituitary–adrenal (HPA) axis, is closely connected with the cytokines. HPA axis activation by cytokines, via the release of glucocorticoids has, in turn, been found to play a critical role in restraining and shaping immune responses. Investigation of the OFQ/N system and G-proteins suggests a role for this receptor as a down-regulator of cytokine, chemokine and chemokine receptor expression.