[Cytokines and the related neurotransmitters in brain-immune interactions]

The brain and the immune system communicate with each other by sharing signal molecules and receptor mechanisms. While the brain may modulate the immunity by controlling the endocrine system and the innervations on the lymphoid organs, the immune system signals the brain via multiple channels mainly using cytokines as signal substances and thereby produces a wide spectrum of acute phase responses such as fever, anorexia, activation of hypothalamic-pituitary-adrenocortical axis and modulation of pain. This mini-review focuses on the issues (1) how the immune system transmits information to the brain and (2) how pro-inflammatory cytokines, interleukin-1 in particular, alter the activities of monoamines (catecholamines and serotonin) and some peptides (CRF, alpha MSH) for the manifestation of acute phase responses.