Effect of Serotonergic Stimulation on the Gut-brain Axis

Selective serotonin reuptake inhibitors increase the level of serotonin. This study will use functional magnetic resonance imaging to examine how subjects with, and without, irritable bowel syndrome patients respond to serotonergic stimulation. Brain activation during emotional and arithmetic tasks and during visceral pain will be measured after serotonergic stimulation using the oral administration of Escitalopram (10 mg). The investigators will further integrate background parameters of the irritable bowel syndrome subjects and healthy controls (such as microbiota composition, genetic markers of serotonergic and inflammatory pathways, intestinal permeability, state of mood and visceral sensitivity) with the responses to the various challenges on the level of functional brain imaging. These responses may reveal a 'footprint' of the individual gut-brain axis function. Analyses of these individual footprints in multiple subjects with and without irritable bowel syndrome may reveal biosignatures characterising certain groups of patients according to specific gut-brain signalling response patterns. These biosignatures may be used to develop an individualised treatment algorithm for irritable bowel syndrome therapy.