Image courtesy of Mishra & Hoon, Science, 2013.
Image shows slices of itch-sensing nervous tissue in normal ("wild-type") mice (left) compared to mice whose itch-sensing pathway has been genetically engineered to be inactive (right). Dark dots on wild-type tissue indicates activation of itch-sensing mechanism.
What makes us scratch an itch? Is the answer . . . in mice?
This is Sandra Tsing Loh with the Loh Down on Science, and a little research to tickle your fancy.
Every pinprick or pat you feel sparks chemical reactions and nerve impulses that lead to the brain. The Big Kahuna then decides: This is pain. That is pleasure.
Enter Mark Hoon from the National Institutes of Health. He embarked on a systematic, well, Itch Hunt. What chemical signals in the body make us scratch? He found a suspicious molecule in mice, abbreviated N-p-p-b. It's located by spinal neurons that send sensory signals to the brain. He tweaked the genes of some mice so they couldn’t produce it.
He then exposed them to itchy things and . . . ? They didn’t bat a whisker! Yet they still felt heat, pain, and touch. But when he injected Nppb into those same mice? They instantly went all fleabag! So, turn its production on? Itch signal reaches brain. Off, it doesn’t.
The finding could lead to new treatments for itchy ailments like eczema and psoriasis.
Then we can finally sing, Ding-dong the itch is dead! Or not.
***** For more 90-SECOND SCIENCE FACTS, click here.*****
This Thursday, from 2-3 p.m. on the LDOS blog: Sandra chats with author Christina Schwarz about her book The Edge of the Earth.
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