Mechanisms of onset in psychosomatic disease - Basic research using animal models

It is well known that immunological functions are influenced by stressors. Psychological stressors influence also usual behaviors such as eating, exercise and sleep. Therefore, it is important to investigate the effect of these behaviors on the immunological functions. In this paper, we analysed effects of nutrition, starvation, sleep deprivation, restriction or emotional behaviors on immunological functions using animal models. 1) (NZB x NZW) F1 autoimmune-prone mice which is used for animal models of systemic lupus erythematosus were compared under the influence of different calorie intakes and different calorie sources. When the energy intake was reduced to 60% of the intake of high calorie groups, survival was doubled in high fat diet group and tripled in carbohydrate group compared to that of high calorie groups. Immunological functions were well maintained in low calorie groups. 2) Functions of macrophage or several T cells were enhanced by short-period of starvation in mice. 3) Sleep deprivation for 3 days suppressed several immune functions in rats. 4) Chemotactic activity of macrophages and number of peripheral white blood cells were almost 50% decreased by 24 hr restriction. Chemotactic activity of macrophages was suppressed by injection of ACTH at dose dependent manner in mice. 5) Using unanesthesized mature cats which were implanted electrode in hypothalamus, emotional behaviors such as restlessness, attack, retreat and searching were elicited by stimulation of the hypothalamus. T cell mitogen responses such as PHA were significantly increased with restlessness and attack, but decreased with retreat and unchanged with searching. B cell mitogen response such as LPS and phagocytosis of neutrophiles were not significantly changed by these behaviors. Therefore, it was suggested that some immunological functions were influenced by emotional behaviors. These results indicate that immunological functions were influenced by various stressors. It depends on the period, degree and method of stressors.