Wed. Sep 28th, 2022

Scratching is highly contagious

Researchers from the University of. George Washington University in St. In St. Louis, they studied the phenomenon in mice. They placed the rodent in a cage in which theóthe screen was located. A video was served to the mice on the screen, on whichórime another mouse was scratching intensively. It only took a few seconds for a mouse in the cage to engage in the same activity.

The researchers found that in a mouse watching its mate while scratching, a region of the mózg called the hypothalamusóral suprachiasmatic nucleus. This part of the mózgu is responsible for behavioral and physiological biological rhythms. It serves as the master biological clock and synchronizes the work of the entire body.

The suprachiasmatic nucleus began to secrete a neurotransmitter called GPR (gastrin-releasing peptide; gastrin-releasing peptide) in a mouse watching the video. Ten years ago, it was proven that this peptide has a key role in transmitting signalsóin the itch between skór and the spinal cord.

– It’s not that a mouse at the sight of another scratching mouse thinks it should also scratch itself. Its mózg immediately begins to send pruritic signals in the form of GRP as a transmitter – explained Dr. Zhou-Feng Chen, coóroutor of the publication in the journal „Science”.

Going further, the researchers blocked the secretion of the GPR neurotransmitter in the mouse, then played the animal the same video of a scratching rodent. It turned out that a mouse with blocked GPR secretion at the sight of another scratching individual did not scratch itself. But as the animal was smeared with an itch-inducing substance, the mouse showed its usual reflexes.

– Scratching is highly contagious. Sometimes all it takes is the mention of an itch for someone around you to start scratching. It’s an instinct. Our research has shown that a single substance and its receptor are enough to mediate such behavior – emphasized Chen. – The next time you yawn or scratch yourself because you notice someone else is doing it, remember that you are not doing it by your own choice. You are influenced by the chemistry of your own mózgu – added the scientist.