Washington: Scratching an itch causes the brain to release the neurotransmitter serotonin which intensifies the itch sensation, a study has found.
Serotonin’s role in controlling pain is known, but this is the first time the release of the chemical messenger from the brain has been linked to itch, Washington University School of Medicine, St Louis, experts said.
Scratching creates a mild pain in the skin, said investigator Zhou-Feng Chen, director of Study of Itch, Washington University. That pain can interfere with itching by getting nerve cells in the spinal cord to carry pain signals to the brain instead of itch signals.
“When the brain gets those pain signals, it responds by producing the neurotransmitter serotonin to control the pain,” Chen explained. “But as serotonin spreads from brain to the spinal cord, we found the chemical can ‘jump the tracks,’ moving from pain-sensing neurons to nerve cells that influence itch intensity,” Chen added.
