Why Do People Itch?

Why Do People Itch?

Ever wonder why and how your brain feels an itch and knows exactly where it is?


Itching, you do it everyday, often, and without thinking about it.  Yet the actual reason and way that the brain knows to itch a specific spot is surprisingly still not fully understood.  Recently, researchers at the University of Minnesota made a breakthrough towards understanding the itch, identifying Nppb (natriuretic polypeptide b), a chemical which helps relay the signal from the skin to the brain. A discovery that finally tells us “why” we itch.

Together with nerve cells, Nppb’s make up the communication system of the body, sending impulses from the body to the brain. The feeling that you have an itch starts with neurons on the surface of the skin, from where a message gets sent via the spinal cord, and then with the help of more neurons, on to the brain.

To verify the way Nppb’s and neurons work together, scientists blocked the production of Nppb’s in mice and then gave them something to induce itching. Without Nppb’s the mice hardly itched.  To further test out this theory they focused on the spinal cord, allowing Nppb’s to be produced but blocking their access to the spine.  Again, the mice hardly itched, this time because those critical messages traveling from the skin to the brain were unable to reach their distention without access to the spinal cord.

Having explained what physically takes place in the body in order for itching to fully occur and be communicated, it might also be of interest to look at why the body would function this way. The evolutionary explanation that sounds most compelling, is that animals have developed a reaction to get rid of anything that attaches itself to the skin.  A pretty good policy to prevent things that might latch on and prove threatening to one’s health.

Source: Esquire

Photo: Spakattacks / flickr

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