The "itch gene" is GRPR (gastrin-releasing peptide receptor), which codes for a receptor found in a very small population of spinal cord nerve cells where pain and itch signals are transmitted from the skin to the brain. The researchers, led by Zhou-Feng Chen, Ph.D., found that laboratory mice that lacked this gene scratched much less than their normal cage-mates when given itchy stimuli.
The laboratory experiments confirmed the connection between GRPR and itching, offering the first evidence of a receptor specific for the itch sensation in the central nervous system. The findings are reported this week in Nature through advance online publication.
Chronic itching is a widespread problem. It can be caused by skin disorders like eczema, or it can stem from a deeper problem such as kidney failure or liver disease. It can be a serious side effect of cancer therapies or powerful painkillers like morphine. For some people, chronic itching can be very disruptive, interfering with sleep or giving rise to scratching that leads to scarring. Effective treatment options for itchy patients are limited.
Historically, scientists regarded itch as just a less intense version of the pain sensation. As a result, research on itching has been somewhat neglected. "Many genes have been identified in the pain pathway," says Chen, associate professor of anesthesiology, psychiatry and molecular biology and pharmacology. "But itch research has lived in the shadow of pain research, and no one knew which gene was responsible for itching in the brain or in the spinal cord until now."
In fact, Chen's team became i
Source:Washington University School of Medicine