AD	Alzheimer’s disease
ADHD	Attention-deficit-hyperactive disorder
AEA	Cannabinoid anandamide
AHLs	N-acyl-homoserine lactones
APC	Antigen presenting cell
ASD	Autism spectrum disorder
BBB	Blood brain barrier
BDNF	Brain derived neurotrophic factor
CC	Colonocytes
CGRP	Calcitonin gene-related peptide
CLRs	C-type lectin receptors
CNS	Central nervous system
DA	Dopamine
DRG	Dorsal root ganglia
EC	Enterocyte in the Glossary
FMT	Fecal microbiota transplantation
GC	Goblet cell
GF	Germ-free
GI	Gastrointestinal
5-HIAA	5-Hydroxy indole acetic acid
5-HT	Serotonin
IAAld	Indole-3-acetaldehyde
IBD	Inflammatory bowel disease
IEC	Intestinal epithelial cell
IEt	Indole-3-ethanol
ILA	Indole-3-lactic acid
IL	Interleukin
LPS	Lipopolysaccharides
KYN	Kynurenine
KYNA	Kynurenic acid
MAMPs	Microbe- associated molecular patterns
MDD	Major depressive disorder
MC	Microfold cell
NLRs	NOD-like receptors
NOD	Nucleotide-binding, and oligomerization domain
NTS	Nucleus tractus solitarii
PAMPs	Pathogen-associated molecular patterns
PANs	Primary afferent neurons
PC	Paneth cell
PD	Parkinson’s disease
PRRs	Pattern recognition receptors
QSM	Quorum sensing molecules
RIG-1	Retinoic acid inducible gene 1
RLRs	RIG-1-like receptors
SCFAs	Short chain fatty acids;
SZ	Schizophrenia
TBI	Traumatic brain injury
TC	Tuft cell
TL	Thoracolumbar
TLRs	Toll-like receptors
TNF-α	Tumor necrosis factor- α
TRP	Transient receptor potential
XA	Xanthurenic acid