Human causes scratching itch

Scratching will temporarily create a pain that makes people feel better.

Why do you scratch when itching?

Millions of people around the world suffer from chronic itching at some point in the body, especially in people with eczema, kidney failure and cancer. On the surface of the skin where itching occurs, people often scratch, a popular way of coping. People scratch until the pain brings relief, Newscientist said.

However, when the pain disappears, the itching goes back and is even more itchy than before. Many cases also cause scratching of the skin or painful skin damage.

Scratching does not help itching but only creates an alternative pain.(Artwork: shutterstock.com)

"People continue to scratch the scratch even though it can cause bleeding," said Zhou-Feng Chen, of the University of Washington Medical School.

Serotonin acts as a neurotransmitter to relieve pain, so Chen and colleagues want to understand whether serotonin is involved in the itching process.

The team conducted experiments on mice, they created genetically modified mice that could not produce serotonin, then they were injected with a chemical that irritates skin itching. The mice that participated in the experiment had almost no desire to scratch the skin to create pain, reducing the itching sensation.

In mice with normal genes that prevent serotonin from leaving the brain, the same results occur. This indicates that the desire of the mouse to appear when there is serotonin from the brain to the stimulated place.

In addition, Chen and colleagues also discovered that nerve cells in the brain, called GRPR, make the itching feeling worse. When serotonin is on its way to an itchy position, it passes and activates the GRPR neurons , which means that the more people scratch it, the more serotonin released by the brain, aggravating the itching feeling. .

The researchers said they could develop a new therapy to control chronic pruritus by preventing serotonin receptors from activating GRPR neurons. However, Gil Yosipovitch, of Temple University in Philadelphia, notes that chronic itching is not only caused by a receptor and a path."Therefore, there is still a long way to develop appropriate treatments on humans , " he said.