[Motility disorders of the small intestine in functional intestinal disorders]

Functional digestive disorders have their origin in disturbances of the digestive motility control. This control ensured primarily by the "gut brain", which is able to integrate sensitive information from mucosal receptors and to organize an appropriate motor response from a choice of predetermined "programs". The gut brain is in close relationship with the central nervous system (CNS) which collects in fact most of the information and modulates the sensitive integration and the motor response of the enteric nervous system (ENS). Thus, a perturbation of the CNS, such as stress, may induce a dysfunctioning of the ENS, resulting in motor disturbances and finally functional digestive disorders. In a first study involving fasting healthy volunteers, we showed that stress produces a significant reduction of the intestinal migrating motor complexes (MMC). In a second study, patients with irritable bowel syndrome (IBS) were subjected to stress and compared to patients with inflammatory bowel disease and to healthy controls. All subjects exhibited a decrease of MMC; however, total depletion was observed in numerous IBS patients, together with a characteristic irregular motor activity which was associated with symptoms. Finally, 24-hour recordings of the intestinal motility in these patients showed an entirely normal pattern during sleep and when abnormalities just awakening in association with symptoms. Stress-induced perturbation of the CNS in IBS patients seems to provoke an inappropriate modulation of the motor activity programmed by the ENS, resulting in motor disturbances and finally in the symptoms of the disease.