State Key Laboratory of Bioactive Substance and Function of Natural Medicines, Institute of Materia Medica, Chinese Academy of Medical Sciences/Peking Union Medical College, Beijing 100050, China.
Molecules. 2021 Mar 4;26(5):1377. doi: 10.3390/molecules26051377.
It has been reported that monoamine neurotransmitters can be produced by gut microbiota, and that several related metabolites of amino acids in these pathways are associated with nervous system (NVS) diseases. Herein, we focused on three pathways, namely, phenylalanine (Phe), tryptophan (Trp), and glutamic acid (Glu), and established an underivatized liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for the quantification of nineteen monoamine neurotransmitters and related metabolites in the gut microbiota. The neurotransmitters and related metabolites included Phe, tyrosine (Tyr), l-dopa (Dopa), dopamine (DA), 3-methoxytyramine, Trp, hydroxytryptophan, 5-hydroxytryptamine (5-HT), 5-hydroxyindole-3-acetic acid (5-HIAA), kynurenine (KN), kynurenic acid (KYNA), melatonin, tryptamine (TA), indole-3-lactic acid (ILA), indole-3-acetic acid (IAA), indolyl-3-propionic acid (IPA), Glu, gamma-aminobutyric acid (GABA), and acetylcholine (Ach). A fluoro-phenyl bonded column was used for separation, and the mobile phase consisted of methanol:acetonitrile (1:1) and water, with 0.2% formic acid in both phases. The compounds exhibited symmetric peak shapes and sufficient sensitivity under a total analysis time of 8.5 min. The method was fully validated with acceptable linearity, accuracy, precision, matrix effect, extraction recovery, and stability. The results showed that neurotransmitters, such as Dopa, DA, 5-HT, GABA, and Ach, were present in the gut microbiota. The metabolic pathway of Trp was disordered under depression, with lower levels of 5-HT, 5-HIAA, KN, KYNA, TA, ILA, IAA, IPA, and Glu, and a higher ratio of KYNA/KN. In addition, some first-line NVS drugs, such as sertraline, imipramine, and chlorpromazine, showed regulatory potential on these pathways in the gut microbiota.
据报道，肠道微生物群可以产生单胺神经递质，而这些途径中几种相关的氨基酸代谢物与神经系统 (NVS) 疾病有关。在此，我们专注于三条途径，即苯丙氨酸 (Phe)、色氨酸 (Trp) 和谷氨酸 (Glu)，并建立了一种未衍生的液相色谱-串联质谱 (LC-MS/MS) 方法，用于定量测定肠道微生物群中的十九种单胺神经递质和相关代谢物。这些神经递质和相关代谢物包括 Phe、酪氨酸 (Tyr)、左旋多巴 (Dopa)、多巴胺 (DA)、3-甲氧基酪胺、Trp、羟色氨酸、5-羟色胺 (5-HT)、5-羟吲哚-3-乙酸 (5-HIAA)、犬尿氨酸 (KN)、犬尿喹啉酸 (KYNA)、褪黑素、色胺 (TA)、吲哚-3-乳酸 (ILA)、吲哚-3-乙酸 (IAA)、吲哚-3-丙酸 (IPA)、Glu、γ-氨基丁酸 (GABA) 和乙酰胆碱 (Ach)。采用氟苯基键合柱进行分离，流动相由甲醇:乙腈 (1:1) 和水组成，两相均含有 0.2%甲酸。在总分析时间为 8.5 分钟的情况下，这些化合物表现出对称的峰形和足够的灵敏度。该方法具有良好的线性、准确性、精密度、基质效应、提取回收率和稳定性。结果表明，肠道微生物群中存在神经递质，如 Dopa、DA、5-HT、GABA 和 Ach。在抑郁状态下，Trp 的代谢途径紊乱，5-HT、5-HIAA、KN、KYNA、TA、ILA、IAA、IPA 和 Glu 的水平较低，而 KYNA/KN 的比值较高。此外，一些一线 NVS 药物，如舍曲林、丙咪嗪和氯丙嗪，对肠道微生物群中的这些途径具有调节作用。
