Department of Internal Medicine VI, University of Tübingen, Tübingen, Germany.
Neurogastroenterol Motil. 2010 Jul;22(7):752-7, e220. doi: 10.1111/j.1365-2982.2010.01527.x.
Acute tryptophan depletion (ATD) is an experimental model to reduce central serotonin levels.
Thirty-eight healthy female subjects were randomly assigned to two groups (ATD and control) in a randomized, double-blinded parallel-group design. Following a standardized and balanced amino acid diet (including 1.21 g tryptophan) on the first day, they received either a protein drink without tryptophan (but substituted by other amino acids) (ATD condition) or the balanced protein drink with tryptophan (control condition) 24 h later. Four hours after its consumption, they were exposed to a standard rotation procedure. Symptom ratings (SR), ratings of hunger and mood scores were taken prior to rotation, at each break, and 15 and 30 min thereafter, together with saliva cortisol samples.
Five subjects could not tolerate the entire rotation procedure and were excluded from analysis. For the remaining n = 33, SR and hunger ratings were higher during ATD than during control conditions, but mood was unaffected. Cortisol levels rose significantly with rotation but were unaffected by ATD. High baseline cortisol levels were associated with lower SR during rotation. The protective effects of morning cortisol were pronounced during the menstrual and follicular phase of the cycle and not present during ovulation and the luteal phase.
CONCLUSIONS & INFERENCES: Acute tryptophan depletion is associated with increased symptoms of nausea in healthy female subjects when exposed to body rotation. Acute tryptophan depletion also increases hunger rating. These opposite effects may indicate independent actions of the serotonin on central and peripheral functions.
急性色氨酸耗竭（ATD）是一种降低中枢 5-羟色胺水平的实验模型。
38 名健康女性受试者被随机分为两组（ATD 和对照组），采用随机、双盲平行组设计。在第一天接受标准化和平衡的氨基酸饮食（包括 1.21g 色氨酸）后，24 小时后他们分别接受不含色氨酸（但用其他氨基酸替代）的蛋白质饮料（ATD 条件）或含色氨酸的平衡蛋白质饮料（对照条件）。消耗后 4 小时，他们接受标准旋转程序。在旋转前、每次休息时以及之后 15 和 30 分钟，以及唾液皮质醇样本采集时，对症状评分（SR）、饥饿感评分和情绪评分进行评估。
5 名受试者无法耐受整个旋转过程，被排除在分析之外。对于剩余的 n=33 名受试者，在 ATD 条件下，SR 和饥饿感评分高于对照条件，但情绪不受影响。皮质醇水平随着旋转显著升高，但不受 ATD 影响。高基线皮质醇水平与旋转过程中的 SR 降低有关。清晨皮质醇的保护作用在月经和卵泡期明显，而在排卵和黄体期则不存在。
当健康女性受试者接受身体旋转时，急性色氨酸耗竭与恶心症状的增加有关。急性色氨酸耗竭也会增加饥饿感评分。这些相反的作用可能表明 5-羟色胺对中枢和外周功能具有独立作用。
