Walters J K, Davis M, Sheard M H
Psychopharmacology (Berl). 1979 Apr 11;62(2):103-9. doi: 10.1007/BF00427121.
In Experiment 1, body weights of rats fed a powdered tryptophan-free (TF) diet decreased monotonically during a 13-day period. Control animals fed the same diet supplemented with 0.5% L-tryptophan gained weight. The groups did not differ significantly in acoustic startle amplitude measured at 2, 4, 6, 7, 9, 11, and 13 days despite a 28% decrease in whole-brain serotonin in the TF rats. In Experiment 2, daily intubation of rats with a syrup form of each diet maintained the two groups' body weights at comparable levels. TF diet intubation decreased whole-brain serotonin by 64% and produced significantly elevated startle amplitudes, which returned to control levels when 0.5% L-tryptophan was added to the diet. Changes in whole-brain serotonin level preceded changes in startle amplitude by several days. In Experiment 3, acute injections of 125 mg/kg L-tryptophan significantly reduced the startle amplitude of TF diet intubated rats and significantly raised their brain serotonin levels. The results show that acoustic startle reflex is increased by a TF diet, provided the animals receive adequate nourishment, and suggest that this facilitation may result from depletion of brain serotonin.
在实验1中，喂食无粉状色氨酸（TF）饮食的大鼠体重在13天内单调下降。喂食补充了0.5% L-色氨酸的相同饮食的对照动物体重增加。尽管TF大鼠全脑血清素减少了28%，但在第2、4、6、7、9、11和13天测量的听觉惊吓幅度在两组之间没有显著差异。在实验2中，用每种饮食的糖浆形式每天给大鼠插管，使两组体重维持在相当水平。TF饮食插管使全脑血清素减少64%，并使惊吓幅度显著升高，当饮食中添加0.5% L-色氨酸时，惊吓幅度恢复到对照水平。全脑血清素水平的变化比惊吓幅度的变化提前几天。在实验3中，急性注射125 mg/kg L-色氨酸可显著降低TF饮食插管大鼠的惊吓幅度，并显著提高其脑血清素水平。结果表明，在动物获得充足营养的情况下，TF饮食会增加听觉惊吓反射，并表明这种促进作用可能是由于脑血清素的消耗所致。
