Studies on the relationships between dietary amino acids and brain neurotransmitters of different aged rats.

1. 研究了在低蛋白饮食中添加氨基酸对大鼠脑神经递质和记忆学习能力的影响。在辨别亮度学习测试中，氨基酸补给组的总反应次数明显高于未补给组。采用微透析法测定大鼠纹状体中酪氨酸（儿茶酚胺合成底物）的释放量。酪氨酸处理引起纹状体多巴胺释放量显著增加。测定了几种茶叶成分，如咖啡因、茶氨酸、谷氨酰胺和r-氨基丁酸对脑神经递质或血压的影响。然后，我们发现大剂量茶氨酸可以降低自发性高血压大鼠的血压。测定了各种脂肪或脂肪酸对脑色氨酸和5-羟基吲哚的影响。观察了给药不同脂肪或脂肪酸后大鼠脑色氨酸的积累。研究了高费雪比（支链氨基酸/芳香氨基酸）多肽混合物与高费雪比氨基酸混合物相比对血清和大脑皮层氨基酸水平以及大脑皮层单胺水平的影响。给药不同种类的肽可改变脑内氨基酸和单胺的浓度。测定了饲喂不同蛋白质种类和不同蛋白质量的大鼠脑蛋白合成率。饲粮蛋白质质量和数量的变化容易影响脑蛋白的合成速率。

1. Effect of amino acid supplementation to a low-protein diet on brain neurotransmitters and memory-learning ability of rats was investigated. In the brightness-discrimination learning test, the number of total responses of rats fed the amino acid-supplemented diet increased as compared with that of rats fed the nonsupplemented diet.2. By using the method of microdialysis, the release of catecholamines from the striatum of rats administered by tyrosine (the substrate of catecholamine synthesis) was determined. Tyrosine administration caused the significant increase of dopamine release from striatum.3. Effect of several kinds of tea components, such as caffeine, theanine, glutamine and r-aminobutyric acid on brain neurotransmitters or blood pressure was determined. Then, we found that the large dose of theanine decreased the blood pressure of spontaneously hypertensive rats.4. Effects of various kind of fats or fatty acids on brain tryptophan and 5-hydroxyindoles were determined. Accumulation of brain tryptophan in rats after administering various fats or fatty acids was observed.5. Effects of peptide mixture with high Fischer s ratio (branched-chain amino acids/aromatic amino acids) on serum and cerebral cortex amino acids levels and on cerebral cortex monoamines levels in comparison with amino acid mixture with high Fischer s ratio were investigated. The concentrations of amino acids and monoamines in brain were changed by the administration of different kind of peptide.6. The rate of brain protein synthesis of rats fed different kind of protein or different amount of protein was determined. The rate of brain protein synthesis was easily affected by the changes in quality or quantity of dietary protein.