Consistent with the importance of TRP channels and neuropeptides in GI inflammation, SP deficiency and RTX-mediated ablation of the TRPV1+ fibers improve DSS colitis without the presence of the proximodistal gradient of inflammation, suggesting substance P released from the TRPV1-expressing sensory neurons is required for this phenomenon (Engel et al., 2012). Here, TRPV1 is linked to colitis.