Interactions between the immune and neuroendocrine systems.

The growing spark of interest in research concerning the molecular links between the nervous, endocrine and immune systems has caused an explosion of new knowledge concerning the fine mechanisms that orchestrate the integrated response to an immune challenge. For instance, elevation in plasma glucocorticoid (GC) levels is one of the most powerful and well-controlled feedback mechanisms on the proinflammatory signal transduction machinery taking place across the organism. Circulating inflammatory molecules have the ability to target their cognate receptors at the levels of blood-brain barrier, the latter in return produces specific prostaglandins (PGs). This chapter presents the brain circuits involved in the activation of the hypothalamic-pituitary-adrenal (HPA) axis by endogenously produced prostaglandin E(2) (PGE(2)) during systemic innate immune insults.