The American journal of gastroenterology
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Am. J. Gastroenterol. · Jan 2014
Sensitivity testing in irritable bowel syndrome with rectal capsaicin stimulations: role of TRPV1 upregulation and sensitization in visceral hypersensitivity?
Abnormal pain perception or visceral hypersensitivity (VH) is considered to be an important mechanism underlying symptoms in a subgroup of irritable bowel syndrome (IBS) patients. Increased TRPV1 (transient receptor potential cation channel subfamily V member 1) expression in rectal biopsies of IBS patients suggests a potentially important role for this nociceptor in the pathophysiology of IBS. However, evidence underscoring the involvement of TRPV1 in visceral perception in IBS is lacking. The objective of this study was to evaluate the role of TRPV1 in VH to rectal distension and clinical symptoms in patients with IBS. ⋯ IBS patients with VH to rectal distension reveal increased pain perception to rectal application of capsaicin, as well as an increased anxiety response. No evidence for TRPV1 upregulation could be demonstrated. As both VH and anxiety are independently associated with increased pain perception to rectal capsaicin application, our data suggest that both peripheral and central factors are involved, with increased receptor sensitivity as a speculative possibility.