These virtually contradictory pro- and anti-inflammatory effects of neuropeptides released from the TRPV1/A1-expressing fibers during chemically-induced colitis were further investigated in the TNBS model, where abrogated CGRP release in the isolated colon preparations and dorsal root ganglia were observed in Trpa1, but not in Trpv1 gene-deficient mice. This evidence concerns the gene TRPA1 and colitis.