Gastrointestinal spice sensor TRPV1 function and pathological modification: pungency is also tasted in the gastrointestinal tract

Capsaicin is a constituent of chili pepper that induces the burning sensation on the tongue. The site of action of capsaicin was discovered to be the transient receptor potential vanilloid receptor subtype 1 (TRPV1) that resides on the membranes of pain- and heat-sensing primary afferent sensory nerves. Immunohistochemical study of the stomach revealed that nerve fibers expressing TRPV1 exist along gastric glands in the mucosa, around blood vessels in the submucosa, in the myenteric plexus, and in the smooth muscle layers. Appropriate capsaicin protects gastric mucosa, but excessive amounts cause gastric damage. Numerous TRPV1 axons were also observed in esophagus, colon and rectum. Capsaicin is not only felt on the tongue, but throughout the digestive tract. It is good for our health if we consume appropriate spices. In this presentation, menthol receptor TRPM8 in gut is also introduced.