Role of transient receptor potential vanilloid subfamily 1 in mediating the analgesic effects of acupuncture on pathological pain

Acupuncture, a traditional oriental intervention for chronic pain, has been gaining worldwide popularity. Transient receptor potential vanilloid subfamily 1 (TRPV1) is a key factor mediating pain production and sensitization. According to multiple studies, TRPV1 is involved the acupuncture-induced relief of pathological pain. Herein, we systematically screened the experimental reports on TRPV1 involvement in acupuncture analgesia, and reviewed the role of TRPV1 in acupuncture in inhibiting different pathological pain and unresolved problems, including inflammatory pain, neuropathic pain, visceral pain, fibromyalgia and cancer pain. At localized acupoints, TRPV1 was involved in the initiation of acupuncture signals. Acupuncture could inhibit the development of pathological pain as well as the transmission of pain signals by suppressing TRPV1 expression and opening activity from the peripheral dorsal root ganglia to the central spinal cord. Furthermore, acupuncture can not only inhibit the expression of TRPV1, but also promote the expression of TRPV1 in the brain to alleviate pain sensation and depression-like behavior. Moreover, the mechanism by which acupuncture regulates TRPV1 may involve neuro-immune crosstalk. In conclusion, the regulation of TRPV1 expression and function may be one of the primary mechanisms by which acupuncture relieves pathological pain, laying the groundwork for future basic research on acupuncture's pain-relieving effects.