Evolving pathophysiological model of functional gastrointestinal disorders: implications for treatment.

The physiological effects of psychological and physical stressors on gut function and brain-gut interactions are mediated by outputs of the emotional motor system in terms of autonomic, neuroendocrine, attentional, and pain modulatory responses. IBS patients with irritable bowel syndroms show an exaggerated responsiveness of this system manifesting itself in altered modulation of gastrointestinal motility and epithelial function, in alterations in the perception of visceral events, and in the associated conscious emotional responses. Animal models are being developed with high face and construct validity for functional visceral disorders that affect the gastrointestinal and urogenital tracts. These animal models suggest plausible targets for future drug development both in the periphery and in the central nervous system.