EFFECT OF THEANINE ON DELAYING EXERCISE-INDUCED FATIGUE AND ITS MECHANISM
LI Min, SHEN Xin-nan, YAO Guo-ying (Department of Nutrition and Food Hygiene, School of Public Health, Fudan University, Shanghai 200032,China)
Objective: To study the effect of theanine on delaying exercise-induced fatigue, and reveal its possible mechanism.Method: Mice were randomized into 4 groups:three groups of theanine at doses of 5.6、8.4、12.6 mg/(kg bw·d),and one control group given distilled water.After 30 d,burdened swimming time,serum BUN,liver glycogen,and monoamine neurotransmitters(5-HT、DA and NE) concentrations in brain were measured.Results: Compared with the control group,both the burdened swimming time and the liver glycogen level of 8.4、12.6mg/(kg bw·d)groups increased significantly (P0.05).All the three theanine groups showed lower serum BUN levels and faster BUN elimination than the control group 60 min after swimming(P0.05).8.4 mg(/kg bw·d)group displayed the least increment of serum BUN. The three theanine groups also showed obviously lower 5-HT levels than the control group in both swimming and non-swimming state(P0.05).The 8.4 mg(/kg bw·d)group in non-swimming mice and 8.4、12.6 mg/(kg bw·d)groups in swimming mice displayed higher DA levels than the control group. The DA/5-HT ratio of three theanine groups in non-swimming mice and the 8.4 mg/(kg bw·d)group in swimming mice were higher than that in control group(P0.05).Conclusion: Theanine has the effect of delaying exercise-induced fatigue possibly through enhancing DA level and inhibiting the synthesis or secretion of 5-HT in brain.