The following is an edited excerpt.
Once thought to be a low-level form of pain, itch is instead a distinct sensation with a dedicated neural circuit linking cells in the periphery of the body to the brain, a study in genetically-modified mice suggests.
Mutant mice lacking one particular protein, called natriuretic polypeptide b, or Nppb, did not respond to itch-inducing compounds, but did respond normally to heat and pain. The researchers also found that when they injected Nppb in the mice’s necks, it put them into a self-scratching frenzy. This occurred both in the mutants and in control mice.
“Our research reveals the primary transmitter used by itch sensory neurons and confirms that itch is detected by specialized sensory neurons,” says Hoon.