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TRPV1 neurons

Who Knew? A Neural Circuit Just for Itching

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Itch line (red) with touch, pain, and temperature lines (white) going through DRG before going to the spinal cord.

Itch-inducing agents activate a discrete population of peripheral sensory neurons that produce a signaling molecule called natriuretic polypeptide b (Nppb). The release of Nppb from these primary pruriceptive neurons triggers a dedicated itch biocircuit to generate the sensation of itch. [Images courtesy of Mark Hoon, National Institute of Dental and Craniofacial Research, NIH]

The occasional itch—be it a bug bite or rash—is annoying. But there are millions of people with chronic itching conditions, like eczema and psoriasis, who are constantly scratching their skin. This is more than a little irritation—it drastically reduces their quality of life and is a perpetual distraction. Current anti-itch treatments include topical corticosteroid creams, oral antihistamines, and various lotions. But researchers at NIH have gone beyond the skin’s surface and discovered a critical molecule at the root of that itchy feeling [1].