Gut Microbiota Signatures of Brain and Peripheral gamma-amino butyric acid (GABA) in Healthy Adult Males

GABA, the primary inhibitory neurotransmitter in the human nervous system, holds significant importance for brain function, affecting neurodevelopment, emotion regulation, and sensory processing. While traditional explanations for variations in brain and blood GABA levels have been genetic, recent research suggests that gut bacteria may also play a role in influencing these levels.

In a study of 251 healthy adult males, scientists explored potential associations between gut microbiota composition, central and peripheral GABA, and related aspects.

Using magnetic resonance spectroscopy, blood enzyme-linked immunosorbent assays, and Flow Cytometry Fluorescent In Situ Hybridisation along with 16S rRNA gene sequencing, the researchers quantified brain GABA, measured blood GABA, and analyzed gut microbiota profiles. The findings revealed a positive association between the number of Bacteroides/Prevotella bacteria and motor cortex GABA+ levels.

Similarly, blood GABA concentrations were positively linked to increased amounts of lactic acid bacteria, Eubacterium rectale/Clostridium coccoides, and Clostridium histolyticum groups. Additionally, predicted microbial gene pathways involved in GABA, propionate, and butyrate biosynthesis showed associations with these bacterial groups.

Interestingly, the study discovered no correlation between brain and blood GABA concentrations, indicating distinct differences between central and peripheral GABA pools. These results provide compelling evidence for the relationship between specific gut bacterial groups and central and peripheral GABA levels, paving the way for future longitudinal studies to investigate potential causal links.

Moreover, the findings suggest the possibility of future intervention studies to manipulate GABAergic processing through targeted manipulation of gut microbiota.