Mental stress-induced changes in plasma serotonin, tryptophan, kynurenine concentrations in healthy participants

In order to investigate the effect of mental stress on the tryptophan metabolism, a stress model of visual display terminals work was loaded on healthy students. Before and just after stress, plasma samples were collected and serotonin, tryptophan and kynurenine were assayed. The plasma concentration of serotonin was increased by visual display terminals work. Both Trp and Kyn concentrations were decreased after stress load. These results suggest that serotonin formation from tryptophan may be accelerated, resulting in the suppressing of kynurenine metabolism from tryptophan. Furthermore, when these subjects were divided into two groups, one group of those accustomed to the personal computer and another group of those not accustomed, the changes of above amines and scores of Profile of Mood States in the latter group were larger than that in the former group. These results also suggest that the activation of the person with a strong psychological load is larger than that of a weak person.