Butterflies in the gut: the interplay between intestinal microbiota and stress

Abstract

Psychological stress is a global issue that affects at least one-third of the population worldwide and increases the risk of numerous psychiatric disorders. Accumulating evidence suggests that the gut and its inhabiting microbes may regulate stress and stress-associated behavioral abnormalities. Hence, the objective of this review is to explore the causal relationships between the gut microbiota, stress, and behavior. Dysbiosis of the microbiome after stress exposure indicated microbial adaption to stressors. Strikingly, the hyperactivated stress signaling found in microbiota-deficient rodents can be normalized by microbiota-based treatments, suggesting that gut microbiota can actively modify the stress response. Microbiota can regulate stress response via intestinal glucocorticoids or autonomic nervous system. Several studies suggest that gut bacteria are involved in the direct modulation of steroid synthesis and metabolism. This review provides recent discoveries on the pathways by which gut microbes affect stress signaling and brain circuits and ultimately impact the host’s complex behavior.

The gut microbiota modulate locomotion via vagus-dependent glucagon-like peptide-1 signaling

“…Commensal microorganisms inhabiting the GI tract have been shown to mediate appetite and metabolic homeostasis 36 . Dysbiosis of the gut microbiota can induce metabolic syndromes, inflammation, and hormone dysregulation 37 – 40 . Strikingly, the levels of CCK, GLP-1, and PYY as well as locomotion 13 – 16 were found to be altered when the microbiota was depleted 37 , 41 .…”