Table 1.

Examples of gut microorganisms that are able to produce molecules with effects on CNS and behavior (↑ = increase; ↓ = decrease).

Gut Microorganism	Molecules, Metabolites and Neurotransmitters Involved	Effects on Gut-Brain Axis
Bifidobacterium longum NCC3001	↑ BDNF	↓ Anxiety and depressive behavior [30,58] ↑ Neuronal plasticity of ENS [58]
Bifidobacterium dentium	↑ GABA	↓ Visceral hypersensitivity [59]
Lacticaseibacillus rhamnosus JB-1	↑ GABA	↓ Anxiety and depressive behavior [59] ↓ Intestinal damage and inflammation [64]
Escherichia coli Nissle 1917	↑ C12AsnGABAOH	↓ Visceral hypersensitivity [61] ↑ Epithelial permeability of GABA [61]
Limosilactobacillus reuteri ATTC-PTA 6475	↑ Oxytocin	↓ Restores social deficits of ASD [24] Promotes DC maturation and immune modulation via IL-10 [65]