Mercer L P, Dodds S J, Schweisthal M R, Dunn J D
Department of Biochemistry, School of Medicine, Oral Roberts University, Tulsa, OK 74171.
J Nutr. 1989 Jan;119(1):66-74. doi: 10.1093/jn/119.1.66.
Histidine (His) is elevated in plasma and brain during protein deficiency as well as in several pathological conditions, leading to the possibility of a direct effect on central nervous system (CNS) function. In this study, groups of weanling rats were fed diets containing graded levels of casein or a single indispensable amino acid (IAA: Leu, Val, Ile, Phe, Trp, Thr, Met or Lys) in order to produce nutritionally-deficient states. Body weight gains and food intakes were recorded daily for 2 wk. Whole brain and serum samples were obtained and analyzed for amino acid (AA) content. All weight gain and food intake responses could be predicted by the Saturation Kinetics Model. The only consistent pattern observed in AA profiles which could be correlated with food intake was an increase in brain His concentrations. Limiting dietary casein or IAA elevated brain His above controls 2.5- and 1.5-fold, respectively. Food intake was generally depressed by 50% at brain His concentrations above 105 nmol/g. Since His is the precursor of the depressant neurotransmitter histamine (HA), systemic increases may be significant in that HA could be a possible cause of the anorexia observed in protein and IAA deficiency.
在蛋白质缺乏以及多种病理状态下，血浆和大脑中的组氨酸（His）水平会升高，这导致其可能对中枢神经系统（CNS）功能产生直接影响。在本研究中，将断奶大鼠分组，喂食含有不同分级水平酪蛋白或单一必需氨基酸（IAA：亮氨酸、缬氨酸、异亮氨酸、苯丙氨酸、色氨酸、苏氨酸、蛋氨酸或赖氨酸）的日粮，以产生营养缺乏状态。每天记录大鼠2周的体重增加和食物摄入量。获取全脑和血清样本并分析氨基酸（AA）含量。所有体重增加和食物摄入反应都可以通过饱和动力学模型预测。在氨基酸谱中观察到的唯一与食物摄入相关的一致模式是大脑中组氨酸浓度的增加。限制日粮中的酪蛋白或必需氨基酸会使大脑中的组氨酸浓度分别比对照组升高2.5倍和1.5倍。当大脑中组氨酸浓度高于105 nmol/g时，食物摄入量通常会降低50%。由于组氨酸是抑制性神经递质组胺（HA）的前体，全身水平的升高可能具有重要意义，因为组胺可能是蛋白质和必需氨基酸缺乏时观察到的厌食症的一个可能原因。
