TRPV1 and colitis: As a first step in testing the hypothesis that nicotine acts to protect against colitis by inhibiting the generation of a proinflammatory TRPV1 agonist in the colon, the effect of pretreating the colon with nicotine before administering capsaicin, a direct TRPV1 agonist that has previously been shown to be highly inflammatory in the rat ileum [13], was tested.