How scratching curbs itching

London, April 06: Itching brings with it that ever-increasing urge to scratch, which always works wonders, but not much is known about the physiological mechanisms behind this phenomenon. University of Minnesota scientists have found that nerve cells play a key role in soothing that tingling sensation.

The researchers have shown that scratching helps relieve an itch by blocking activity in some spinal cord nerve cells that transmit the sensation to the brain. However, the above-mentioned phenomenon only works during itchiness because scratching at other times doesn’t make much of a difference. Earlier research pointed towards a specific part of the spinal cord - the spinothalamic tract – to play a key role. It was found that nerve cells in this area turned more active on application of itchy substances to the skin. In the current research on primates, the researchers found that scratching the skin blocks activity of nerve cells in the spinothalamic tract during itchiness. This prevents the spinal cord from transmitting signals from the scratched area of skin to the brain. Professor Gil Yosipovitch, an expert on itching from Wake Forest University in North Carolina, said that the finding was "potentially significant". "Although there is a long way to go, methods that can induce a pleasurable scratch sensation without damaging the skin, via mechanical stimuli or drugs that can inhibit these neurons, could be developed to treat chronic itch,” The BBC quoted him as saying. A research article on this study appears in the journal Nature Neuroscience. ANI