Question: neurotransmitters that are modified amino acids?
Answer: Common NTs in humans, such as acetylcholine (ACh), the modified amino acids glutamate and γ-aminobutyric acid (GABA), and biogenic amines like dopamine (DA), serotonin (5-HT), and the well-known histamine (His), are also found in some animal foods, fruits, edible plants, and roots [9].