The study – published in Molecular Psychiatry – reveals how normal adult brain function depends on the presence of gut microbes during development.
Led by Dr Gerard Clarke Scientists from the University College Cork, Ireland, the new research shows that the absence of bacteria during early life of mice significantly affected serotonin concentrations in the brain in adulthood.
The research also highlighted that the influence is sex dependent, with more marked effects in male compared with female animals.
"These findings are fascinating as they highlight the important role that gut bacteria play in the bidirectional communication between the gut and the brain, and opens up the intriguing opportunity of developing unique microbial-based strategies for treatment for brain disorders," said Professor John Cryan – senior author on the publication.
This research has multiple health implications as it shows that manipulations of the microbiota for example by antibiotics but also by dietary interventions such as probiotics, could have profound knock-on effects on brain function, suggest the researchers.
"We're really excited by these findings" said lead author Dr Gerard Clarke. "Although we always believed that the microbiota was essential for our general health, our results also highlight how important our tiny friends are for our mental wellbeing."
The authors added that their results demonstrate that central nervous system (CNS) neurotransmission “can be profoundly disturbed by the absence of a normal gut microbiota.”
Source: Molecular Psychiatry
Published online ahead of print, doi: 10.1038/mp.2012.77
“The microbiome-gut-brain axis during early life regulates the hippocampal serotonergic system in a sex-dependent manner”
Authors: G. Clarke, S. Grenham, P. Scully, P. Fitzgerald, R.D. Moloney, F. Shanahan, T.G. Dinan, J.F. Cryan