[Stress and gastroenterology: an immunoneuroendocrinological approach].

The numerous interactions between the immune and neuroendocrine systems are being studied in a rapidly expanding interdisciplinary field called "immunoneuroendocrinology" or "psychoneuroimmunology". We have recently reported that interleukin-1 (IL-1), a cytokine mainly produced by activated monocytes and macrophages, has various central nervous system (CNS) actions besides its immunological activities. Among these activities, for example, IL-1 activates the hypothalamic-pituitary-adrenal axis, a main hormonal response to stress, by stimulating the release of corticotropin-releasing factor from the hypothalamus. IL-1 also acts centrally in the brain to decrease food intake in a dose-related manner, suggesting that anorexia, a typical clinical manifestation frequently observed in acute infectious diseases, may be caused by IL-1, a cytokine that is released under such conditions as acute infection. Furthermore, we have very recently found that IL-1 has potent antisecretory and anti-ulcer actions mediated by the CNS. Based upon these results, we have proposed that there may be an "immune-brain-gut" axis, in which IL-1 acts as an afferent signal and gastric functions as efferent one. At this symposium, by presenting some of our data on the CNS effects of IL-1, we report the potential of these immunoneuroendocrinological studies for a better understanding of the pathophysiology of stress-induced gastrointestinal disorders.