At last there's hope for chronic itching sufferers

Itching is one of the most common sensations in our daily life, but the neural mechanism underlying the irritating sensation has been largely unknown.

Local neuro-scientists are working to bring the answer to this mystery.

The researchers for the first time revealed how itch signals are transmitted from the spinal cord to the brain by discovering a central neural pathway, the Institute of Neuroscience of the Chinese Academy of Sciences said over the weekend.

The paper was published online in Science, a world leading science journal, on August 18.

The study's clinical application in the future will also contribute to ease suffering for many people with chronic itching due to skin or liver diseases.

Itching is an unpleasant sensation making its sufferers wants to scratch. For ordinary people it is irritating but bearable.

“But for patients with skin or liver diseases, chronic itching could lead to uncontrollable scratching,” said Dr Sun Yangang, a leading researcher of the team.

“Their scratching could not only cause skin damage, but even affect their sleep and quality of life,” Sun added. Without proper understanding over the mechanisms underlying itch processing, most treatments for chronic itching are based on experience and the medication used is often ineffective or has side effects.

A better understanding of the mechanism of itching, Sun said, will help to develop more effective and specific treatment of chronic itching.

To feel itching, the signal on skin must first be transmitted to the spinal cord, and later to the brain. But how the itch-specific neurons send signals from the spinal cord to the brain has mystified scientists for a long time. Previous studies mainly focused on the brain or spinal cord separately.

The team discovered a pathway between the spinal cord and the brain, whose inhibition can largely suppress itch-induced scratching. They also confirmed that an area in the brain called "parabrachial nucleus" serves as a first critical central relay in the itch processing.

Sun compared the neural network as a transportation network of a city, with a metro and train stations. To explore and understand the whole network is one of the biggest missions in the field of neuroscience.

“Each station has its own role and route, while parabrachial nucleus is just the first station we found for the itch processing in brain,” said Sun. “Through the first station, we will work to explore other sections of the network in the future.”

Ti Gong