A Study on Immunomodulation and Serotonin Metabolism Changes by Immobilization Stress in Mice Fed Tryptophan Supplemented Diet.

고 트립토판 식이를 섭취한 마우스에서 Immobilization 스트레스로 인한 면역변조와 Serotonin 대사의 변화에 대한 연구

We fed high trypotophan diet(3.5% tryptophan/diet(w/w) to mice for 7 days and treated then with 3 hour immobilization(IMMB) stress to investigate tryptophan metabolism and immunomodulation. The levels of serum tryptophan, brain tryptophan, serotonin(5HT) and 5-hydroxyindoleacetic acid(5HIAA) in the tryptophan diet fed animals were higher than those of the normal diet fed animals. Feeding tryptophan supplemented diet to stressed animal significantly decreased the levels of serum and brain tryptophan and 5HT levels. However, the amount of 5HIAA which is the metabolite of serotonin was increased in brain. Plasma corticosterone level was increased by the stress in both groups but the degree of this increase was smaller in high tryptophan fed animals. The relative numbers of CD8+ T cells, CD4+ T cells and B cells in spleen were decreased in high tryptophan diet fed and stressed animals compared to control diet fed and no stressed animals. CD8+ T cells decreased more than CD4+ T cells. The decrease of CD8+ T cells in high tryptophan fed and stressed animals was similar to that in high tryptophan fed animals or normal diet fed and stressed animals. Stress and tryptophan supplement acted synergistically to decrease the number of B cells. This study suggests that stress and tryptophan supplement could modify the number of lymphocyte cells, and indicates that the interaction of stress and tryptophan supplement on immune fuction depends on the types of immune cells.