AHR	Aryl Hydrocarbon Receptor
AMPA	α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid
BD	Bipolar depressive disorder
CD26	Cluster of Differentiation marker 26, and a dipeptidyl-peptidase-4 enzyme
CNS	Central nervous system
CSF	Cerebrospinal fluid
CTLA-4	Cytotoxic Lymphocyte Antigen-4 (CTLA-4)
cyp 1A1	Cytochrome P450, family 1 metabolic enzyme
GiT	Gastrointestinal tract
GITR-L	Glucose-Induced TNF Receptor-Related Ligand
GPR35	G-Protein Coupled Receptor-3
HCAR	Hydroxy-carboxylic acid receptors
5-HIAA	5-hydroxyindole-acetic acid
3-HK	3-hydroxykynurenine
5-HT	5-hydroxytryptamine, serotonin
HtrA-1	High temperature requiring protein A-1
IDO	Indoleamine-2,3-dioxygenase
IFN-γ	Interferon-γ
IL-	Interleukin-
IL4i1	Interleukin-4-induced protein-1
I3PA	Indole-3-propionic acid
I3PyA	Indole-3-pyruvic acid
JNK	Jun-N-terminal kinases
KAT	Kynurenine aminotransferase
KMO	Kynurenine-3-mono-oxygenase
KP	Kynurenine pathway
K/Q ratio	Kynurenic acid/quinolinic acid ratio
K/T ratio	Kynurenine/tryptophan ratio
LAT-1	Large Neutral Amino Acid Transporter-1
LPS	Bacterial lipopolysaccharides
MDD	Major depressive disorder
MRP4	Multidrug resistance associated protein 4
NAD	Nicotinamide adenine dinucleotide (NAD+)
NMDA	N-methyl-D-aspartate
OAT	Organic Anion Transporter
PAH	Para-aminohippuric acid
PBMCs	Peripheral blood mononuclear cells
PFC	Prefrontal cortex
PSA	Prostate Specific Antigen
Ro61-8048	3,4-dimethoxy-N-[4-(3-nitrophenyl)thiazol-2-yl]benzenesulphonamide
TDO	Tryptophan-2,3-dioxygenase
TGF-β1	Transforming Growth Factor-β1
TLR	Toll-Like Receptors
TNF	Tumour Necrosis Factor-α