Research A molecule causes itching

Itching is caused by molecules in the spinal cord

05/25/2013

Itchy skin can be very uncomfortable. US researchers have now discovered how the stimulus is to scratch themselves. Debt is therefore a single molecule that attaches to a nerve cell in the spinal cord. In mouse experiments, the Nppb molecule could be identified as the trigger for the itching.

Molecule plays a key role in the development of itching
There are many causes of itching such as allergies, skin diseases or internal organs. But what exactly triggers the attraction of scratching oneself was previously unknown. Recently, US scientists at the National Institutes of Health (NIH) identified a single molecule as the cause of the unpleasant sensation. Like the researchers in the trade magazine „Science“ In experiments with mice, it was shown that the Nppb molecule, which is found in a nerve cell in the spinal cord, is responsible for the itching. After the Nppb molecule had docked to the nerve cell, it sent a signal to the mice, which was interpreted as itching in the brain. Nppb is one of the so-called neurotransmitters, chemical messengers that act as transmitters of sensory signals between nerve cells.

For the investigations, the scientists removed a part of the mice, the Nppb molecule or the nerve cell. „We tested Nppb for its possible role in triggering various sensations without success“, explained Santosh Mishra, lead author of the study. „When we exposed the mice that lacked Nppb to several itching substances, we made astonishing observations: nothing happened. The mice just did not scratch.“

The study also shows that certain scientific assumptions are not correct. „Our work shows that itching, not previously thought of as a form of mild pain, is a distinct sensation that is clearly linked to the nervous system with the biochemical equivalent of its own dedicated conduit to the brain“, Reported study leader Mark Hoon.

Research to control the itching is still in its infancy
The researchers suspect that the results of their studies in mice are also applicable to humans, since both nervous systems are similar. In the future, drugs could be developed that target specific molecules and thus prevent itching. If successful, the suffering of millions of people worldwide suffering from chronic pruritus, such as psoriasis, could be alleviated. However, it will be some time before these drugs are developed. Nppb also occurs in the kidneys, heart, and other parts of the body, so controlling the molecule in the spinal cord could potentially cause problems at another stele.

„Now the challenge is to find similar biocirculations in humans, to evaluate what is there and to identify unique molecules that can target chronic itching without causing unwanted side effects“, said Hoon. „So this is a start, not a degree. "(Ag)

Picture: S. Hofschlaeger.