ON THE CUTTING EDGE: Why Scratching Feels So Good
An animal study by University of Minnesota researchers published in the journal Nature Neuroscience finds that scratching an itch inhibits transmission of itch signals from the spinal cord to the thalamus in the brain. After sedating long-tailed macaques and attaching electrodes to the nerves that send itch signals to the brain, the researchers injected an itch-producing substance under the skin of one leg. When the researchers scratched where it itched the nerves stopped firing altogether, or the rate of firing slowed considerably for as much as 40 seconds, which provided relief. The researchers also scratched the leg without first making it itch, and neuronal activity increased in response to the stimulation.
Lead researcher Glenn Giesler tells Reuters: "There are more than 50 diseases that produce itch that can't be easily treated" and if researchers can figure out how to stop the signals from reaching the brain without repeated scratching - which can lead to skin infection - new treatments can be developed for people not helped by antihistamines or steroid creams.
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