Novel therapeutics in the field of capsaicin and pain

Capsaicin, a pharmacologically active agent found in chili peppers, causes burning and itching sensation due to binding at the transient receptor potential vanilloid-1 (TRPV-1) receptor, a polymodal receptor critical to the sensing of a variety of stimuli (e.g., noxious heat, bidirectional pH), and subsequent activation of polymodal C and A-δ nociceptive fibers. Acutely, TRPV-1 activation with peripheral capsaicin produces pronociceptive effects, which extends to the development of hyperalgesia and allodynia. However, capsaicin has been reported to display antinociceptive properties as well, largely through TRPV-1-dependent mechanisms. Local application of high concentration of capsaicin is used for neuropathic pain and repeated stimulation of TRPV-1 induced an improvement of epigastric pain in irritable bowel syndrome and dyspepsia patients by desensitization of nociceptive pathways. New TRPV-1 agonists are currently under preclinical study and TRPV-1 antagonists are in early clinical development as analgesics. The TRPV-1 pathway might be a novel target for therapeutics in pain sensitivity.