Neuroactive probiotics

In the journal Bioessays, an article and accompanying essay, offer a new look at probiotics and how they can function mechanistically as delivery vehicles for neuroactive compounds. “Until recently the idea that probiotic bacteria administered to the intestine could influence the brain seemed almost surreal,” said Dr Gregor Reid, from the University of Western Ontario,”Yet in a paper by Professor Mark Lyte from Texas Tech University Health Sciences Center, the concept is supported by studies showing that microbes can produce and respond to neurochemicals, which can induce neurological and immunological effects on the host.” Dr Lyte proposes that through a unifying process of microbial endocrinology, neurochemical-producing probiotics could act as a delivery mechanism for neuroactive compounds that could improve a host’s gastrointestinal and psychological health.

Bacteria have been well documented to produce an extensive range of neurochemicals for which receptor-based mechanisms of action have been well studied in intestinal and extra-intestinal host physiology for decades, for example, GABA, norepinephrine, serotonin, dopamine and acetylcholine.

“This paper proposes a new field of microbial endocrinology, where microbiology meets neuroscience,” said Lyte. “There is already evidence to suggest that the connection between gut microbes and the nervous system represents a viable route for influencing neurological function. A recent study in mice, for example, showed that the presence of neurochemicals such a serotonin in the bloodstream was due to direct uptake from the gut.”

In his hypothesis Professor Lyte considers the selection of probiotics, such as lactobacilli and bifidobacteria, and how the active uptake of neurochemicals, generated by bacteria in the gut and circulated through a patient’s bloodstream, represents a pathway for probiotics to exert extra-intestinal effects including behavioral changes.

1. M. Lyte. Probiotics function mechanistically as delivery vehicles for neuroactive compounds: Microbial Endocrinology in the design and use of probiotics. BioEssays, 2011; DOI: 10.1002/bies.201100024
2. G. Reid. Neuroactive probiotics. BioEssays, 2011; DOI: 10.1002/bies.201100074