ALS	Amyotrophic lateral sclerosis
AD	Alzheimer’s disease
5-HT	5-Hydroxytryptamine; serotonin
BBB	Blood-brain barrier
BCH	2-Aminobicyclo heptane-2-carboxylic acid
CAT1	Cationic amino acid transporter 1
CNS	Central nervous system
ECF	Extracellular fluid
IDO	Indoleamine 2, 3-dioxygenase
IF-γ	Interferon-γ
LNAA	Large neutral amino acids
LAT1	l-type amino acid transporter 1
MeAIB	α-Methylaminoisobutyric acid
NAA	Neutral amino acids
NMG	N-methyl d-glucamine
ND	Neurodegenerative disease
PD	Parkinson’s disease
RT-PCR	Real-time polymerase chain reaction
TDO	Tryptophan 2, 3-dioxygenase
TNF-α	Tumor necrosis factor α