Signalling in the Gut

Signalling via the gut-brain axis has gained a lot of attention because of the growing interest in modulating brain activity through microbiome-targeting strategies. The sensory nerve fibres which arise from neurons in the nodose ganglion and dorsal root ganglia and innervate the entire gastrointestinal tract constitute the neuronal component of this gut-brain axis. The activation patterns of these sensory nerves have been studied in electrophysiological experiments using either flat sheet or tube preparations in the context of intestinal sensing and visceral pain. A recent study from our lab, in line with other studies of somatic pain, has now demonstrated that these nerves can sense metabolites released by the opportunistic pathogen Staphylococcus aureus. Given that the secretion of these neuromodulatory mediators was dependent on bacterial density, these findings suggest that sensory nerve fibres also constitute an important signalling mechanism for microbiota-gut-brain communication.