Why does Scratching Relieve the Itching

Scratching ; we all know it  is the best solution for itching; But why does it relieve us? What mechanisms intervene in this relationship?

Numerous studies have analyzed this matter, without, until now, a definitive conclusion has been reached. But, , an American investigation throws a little more light on the subject. According to his data, scratching works because it is capable of inhibiting the activity of a type of neurons in the spinal cord that transmit, among other sensations, that of itching.

Glenn Giesler, principal author of the research, must have previously itching so that the simple friction of the skin is able to block the activity of these cells, since it is precisely this last sensation that makes them ‘sensitive’ to scratching.

“Our data indicate that the itching produces a certain condition that causes these neurons of the spinothalamic tract [in the spinal cord] to be inhibited by scratching,” he explains.

This expert from the University of Minnesota (United States) points out that, as his team has confirmed, if there is no previous pruritus stimulus, scratching does not produce any effect on these cells.

The researchers, whose work appears in the pages of the journal ‘Nature Neuroscience’, started from the results of several studies that had shown that the spinothalamic tract responds to the activity of certain agents capable of producing itching and activated by transmitting this information to the brain .

To advance the analysis, these scientists conducted a experiment in primates that consisted in analyzing their response to the exposure of histamine, a substance capable of generating itching.

Their results showed that the neurons of their spinothalamic tract showed less activity in the moments after scratching.

On the other hand, “the activity of the neurons was not reduced if the scratching had occurred before exposure to histamine or in response to other stimuli,” the researchers explain in their work.

“Our next step in the research is precisely to understand how this process of inhibition occurs, to know if it occurs completely in the spinal cord and what neurotransmitters are involved,” says Giesler.

Your expectations are good. “We hope to find means – perhaps medicines or some type of electrical stimulation – that are able to start the inhibition that scratching gets without it being necessary, which would avoid the damage they suffer [some patients] need scratching continuously, “he concludes.

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