We know why we scratch—because it feels so good—but why do we itch? Specifically, what is it that tells our brains to drive us crazy when we’re wearing itchy pants, or when we haven’t washed a shirt for a few too many days?
According to new research out of Duke University, our skin has a special nerve dedicated to making us want to scratch. Even better, the knowledge may mean new drugs that could neutralize the itch, which is good news for people who attract more than their fair share of mosquitos.
The skin, our biggest organ, keeps our internals inside and keeps everything else out. But the study published in the Journal of Biological Chemistry, shows that the skin isn’t just a protective sack. Special skin cells, sensitive to certain irritants, talk directly to our nerve cells, giving them a hotline to the brain.
"Now it turns out skin has features reminiscent of sensory-neural cells that are instrumental in facilitating the sensation of itch," says co-author Yong Chen.
The cells responsible for itching are called TRPV4, which are also involved in releasing pain and itch-causing molecules into the skin when we get sunburned. By switching off the TRPV4 gene in genetically modified mice, the team was able to see if TRPV4 was directly in charge of itching. When the mice were exposed to itchy chemicals, the ones with reduced TRPV4 scratched "much less" than those with normal levels of TRPV4.
Beneath the surface, as it were, TRPV4 works by triggering a "rush of calcium into the cell," flipping a molecular switch. Manipulating this process using drugs should allow us to control and suppress this response.
"We can now envision developing topical treatments for the skin that target specific molecular pathways to suppress itch and inflammation," says lead author Wolfgang Liedtke.
Imagine: A rub-on cream that actually stops mosquito bites from itching. This might be the biggest discovery of the century so far, at least in terms of improving summer-evening grill-outs, or camping trips, that is.