This effect is known as «gate control» theory, which proposes that acupuncture can block the action of pain fibers in the spinal cord. (nessexotic.com)
They can receive signals from itch fibers and also pain fibers,» says study coauthor and neuroscientist at Johns Hopkins University Xinzhong Dong. (sciencedaily.com)
However, UVB irradiation does not give rise to spontaneous activity in pain fibers of C - type, while this is the case after topical application of capsaicin. (imieuropain.org)