Disruptive physiology: olfaction and the microbiome-gut-brain axis

Area of Science:

• Neuroscience and Microbiology
• Integrative biology exploring the holobiome concept

Background:

• The microbiome-gut-brain axis (MGBA) is increasingly recognized for its role in modulating animal behavior.
• Olfactory systems, including classical olfactory receptors and other families like trace-amine associated and formyl peptide receptors, are widely distributed throughout the body.
• Bacteria produce numerous odorants that influence species recognition, predator detection, and social cues.

Purpose of the Study:

• To review the field of olfaction and chemosensation in the context of microbial interactions and the MGBA.
• To highlight the importance of integrating olfactory system knowledge into microbiome and behavior studies.
• To explore the implications of olfaction in understanding and modulating behavior.

Main Methods:

• Literature review synthesizing current knowledge on olfaction, chemosensation, and the MGBA.
• Examination of the evolutionary conservation and genetic basis of olfactory systems.
• Analysis of the role of bacterial odorants and their impact on receptor activation and behavior.

Main Results:

• Olfactory receptors are not limited to the nose and are found in various organs, influencing functions beyond smell.
• Bacterial products, such as β-phenylethylamine, can activate olfactory receptors to control emotions like fear and aggression.
• The influence of microbial odorants on brain function and behavior is a rapidly expanding area of research.

Conclusions:

• Integrating olfaction into MGBA research is essential for a comprehensive understanding of behavior.
• Olfactory pathways offer novel targets for modulating behavioral changes.
• The holobiome concept underscores the need to study organisms alongside their associated microbial communities.