[Influence of cytokines on neuroendocrine functions during immune response. Mechanisms involved and neuronal pathways].

The action of immune-system derived cytokines to stimulate release of corticotropin-releasing factor (CRF) from the hypothalamus and the consequent elaboration of ACTH and corticosteroids release has provided an especially useful model to investigate the nature of the inter-communication of neuroendocrine and immunological pathways. Substantial evidence also exists to support the production of cytokines within the mammalian central nervous system (CNS). These brain-derived cytokines may function to regulate specific challenges, such as immunological, trauma-induced, physical, and emotional stress, to the CNS as well as to receive input from immune signals in the systemic circulation. The mechanisms involved in the effects of cytokines, such as interleukin-1 (IL-1) alpha and beta, on selective neuroendocrine functions are presented in this review. Particularly, the neuronal circuitries used by IL-1 of peripheral and central origin to modulate neuroendocrine CRF motoneurons and the activity of the hypothalamic-pituitary-adrenal (HPA) are described. The influence of an immune activation on neuroendocrine functions and brain neuronal activation is also presented.