Washington: Researchers have uncovered a specific set of nerve cells that signal itch but not pain, a finding that may settle a decades-long debate about how the two sensations are different.The study, if confirmed in humans, will help in developing treatments for chronic itch, including itch caused by life-saving medications.
At the heart of the discovery is a type of sensory nerve cell whose endings receive information from the skin and relay it to other nerves in the spinal cord, which then coordinates a response to the stimulus. Published in Nature Neuroscience, the study suggests that even when the itch-specific nerve cells receive stimuli that are normally pain-inducing, the message they send isn’t “That hurts!” but rather “That itches!”
Pain and itch are both important sensations that help organisms survive. And pain is arguably more important because it tells us to withdraw the pained body part in order to prevent tissue damage.
The scientific controversy over pain and itch centers around a group of nerve cells known to respond electrically to painful stimuli such as molecules of capsaicin.