Marsh Abigail A, Finger Elizabeth C, Buzas Beata, Soliman Niveen, Richell Rebecca A, Vythilingham Meena, Pine Daniel S, Goldman David, Blair R J R
Mood and Anxiety Program, National Institute of Mental Health,National Institutes of Health, Bethesda, MD 20892, USA.
Psychopharmacology (Berl). 2006 Dec;189(3):387-94. doi: 10.1007/s00213-006-0581-2. Epub 2006 Sep 30.
Genotype at the 5' promoter region (5-HTTLPR) of the serotonin transporter has been implicated in moderating the effects of acute tryptophan depletion on neurocognitive functioning. Acute tryptophan depletion has been associated with the processing of fear-relevant cues, such as emotional expressions, but the effect of genotype at the 5-HTTLPR has not been assessed.
The present study investigated the effects of acute tryptophan depletion on the recognition of standardized facial expressions of emotions in healthy volunteers classified as ll homozygotes or s carriers.
A double-blind between-groups design was used with volunteers randomly selected to ingest capsules containing an amino acid mixture specifically lacking tryptophan, or placebo capsules containing lactose. 5 h after capsule ingestion, subjects were required to identify anger, disgust, fear, happiness, sadness, and surprise expressions that progressed from neutral to each full emotional expression in 5% steps.
Tryptophan depletion significantly impaired the recognition of fearful facial expressions in s carriers but not ll homozygotes. This impairment was specific to fear expressions. No significant differences in the recognition of other expressions were found. Free tryptophan levels were correlated with fear recognition in s carriers but not ll homozygotes.
The effects of acute tryptophan depletion on the processing of emotional expressions varies as a function of genotype at the 5-HTTLPR. Depletion impairs the recognition of fear in s carriers but not ll homozygotes. This finding reinforces the importance of considering genotype when assessing the behavioral effects of pharmacologic modulation.
血清素转运体5'启动子区域（5-HTTLPR）的基因型与调节急性色氨酸耗竭对神经认知功能的影响有关。急性色氨酸耗竭与恐惧相关线索（如情绪表达）的处理有关，但尚未评估5-HTTLPR基因型的影响。
本研究调查了急性色氨酸耗竭对健康志愿者（分为ll纯合子或s携带者）识别标准化面部情绪表达的影响。
采用双盲组间设计，志愿者被随机选择摄入含有特定缺乏色氨酸的氨基酸混合物的胶囊，或含有乳糖的安慰剂胶囊。在摄入胶囊5小时后，受试者被要求识别从中性表情开始，以5%的步长逐渐过渡到每种完整情绪表情的愤怒、厌恶、恐惧、快乐、悲伤和惊讶表情。
色氨酸耗竭显著损害了s携带者对恐惧面部表情的识别，但对ll纯合子没有影响。这种损害仅限于恐惧表情。在识别其他表情方面未发现显著差异。游离色氨酸水平与s携带者的恐惧识别相关，但与ll纯合子无关。
急性色氨酸耗竭对情绪表达处理的影响因5-HTTLPR基因型而异。耗竭会损害s携带者对恐惧的识别，但对ll纯合子没有影响。这一发现强化了在评估药物调节的行为效应时考虑基因型的重要性。
