Chronic pelvic pain is a poorly understood but sufficiently debilitating clinical condition primarily affecting women. Few diagnostic and treatment options are available for this understudied patient population, which is estimated at 9.2 million in the United States. The causes of chronic pelvic pain are numerous but may involve gynecologic, urologic, gastrointestinal, musculoskeletal, neuronal, or psychological origins as well as combinations thereof. The urinary bladder and colorecmm are two of the larger pelvic organs thought to be affected primarily in these disorders, and thus, it is not surprising that interstitial cystitis (IC) and irritable bowel syndrome (IBS) are two of the commonest causes of chronic pelvic pain. The observed overlap of chronic pelvic pain disorders such as IC and IBS suggests a common underlying etiology or even cross-organ (neurogenic) sensitization. Using a newly developed rodent model for studying afferent-mediated interactions of the pelvic organs in the rat, we will investigate the hypothesis that chronic irritation of the distal colon may adversely influence and sensitize urinary bladder afferents leading to neurogenic cystitis and its associated physiologic sequelae. The studies proposed in this application will attempt to shed more light on the overlap and etiology of chronic pelvic pain syndromes and the role of cross-organ, afferent sensitization.