TRPV1 and irritable bowel syndrome: Moreover, in an in vivo somatic pain setting, co-administration of non-hyperalgesic dosis of PAR2 agonist and capsaicin led to hyperalgesia that was absent in Trpv1−/− mice.52 Since TRPV1 is also a key ion channel for visceral hypersensitivity in maternal separated rats and patients with IBS,26,38 these somatic findings on PAR2-mediated afferent sensitization may be relevant for IBS as well.