Abstract:Experiments were conducted to evaluate the effect of tryptophan on behavioral reactivity of stressed mice and its relation with hypothalamic 5-hydroxy tryptamine(5-HT).60 mice were randomly divided into 4 groups:NC group(saline administration),CUS group(saline administration and chronic stress stimulation),CUS-H group(high-dose tryptophan administration and chronic stress stimulation) and CUS-L group(low-dose tryptophan administration and chronic stress stimulation).A chronic stress model was established to CUS,CUS-H and CUS-L group.Meanwhile,different levels of tryptophan were administrated to CUS-H and CUS-L group.From the fifth week of establishing the model,open-field test,tail-suspension test,sugar preference test,forced swimming test and water maze were measured,and the hypothalamic serotonin level was assayed.The results are as follows:Compared to CUS and NC group,a notable increase(p<0.05) in open-field test score and a marked decrease(p<0.01)in immobile time of tail suspension test of CUS-H group were discovered,the sugar preference of CUS-H group were also decreased compared to CUS group(p<0.01).Besides,the immobile time of force swimming test was lower than NC group(p <0.01);Learning and memorizing ability of stressed mice was indistinctively improved after tryptophan administration;The Hypothalamic 5-HT content was obviously increased(p<0.01) after tryptophan administration.The results suggested that administration of tryptophan increase the content of hypothalamic 5-HT and effectively reverse the variation of stress resistant capability of stressed mice.The strengthened stress resistant capability might be related to the enhanced level of hypothalamic 5-HT.
