Neuropathophysiology of functional gastrointestinal disorders

Figure 10 Heuristic model for brain-gut interaction in response to stress. The ENS is a minibrain located in close apposition to the gastrointestinal effectors it controls. Enteric mast cells are positioned to detect foreign antigens and signal their presence to the ENS. When, stimulated mast cells release several paracrine mediators simultaneously. Some of the mediators signal the ENS while others act as attractant factors for polymorphonuclear leukocytes responsible for acute inflammatory responses. The ENS responds to the mast cell signal by initiating a defensive program of coordinated secretion and propulsive motility that functions to rapidly expel the source of antigenic stimulation from the bowel. Symptoms of abdominal pain, fecal urgency and watery diarrhea result from operation of the defense program. Neural inputs to enteric mast cells from the brain stimulate simultaneous release of chemoattractant factors for inflammatory cells and chemical signals to the ENS with effects that mimic the symptoms of antigenic detection by the mast cells. Stress activates this brain-to-mast cell connection.