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Merkel cells in the skin are decreased in people and people with dry skin.
In addition to the usual all "symptoms" aging, for example, memory impairment, or the appearance of gray hair, the skin of elderly people often becomes hypersensitive: it is starting to itch at the slightest touch. Experts do not know what caused such disease, called allocate (alloknesis), and, most important, I do not know how to treat it.
Meanwhile, American scientists have recently identified a paradoxical mechanism behind this disorder. The reason lies in the loss of special skin cells.
Specialists explain that chemical itching occurs as a result of the reaction of the immune system to a foreign substance (saliva after the bite of a mosquito, for example). And the emergence of chronic mechanical or itching is usually triggered by a light exposure to any object.
Constant itching haunts many people, and they start to scratch the fragile and dry skin, which can lead to serious health problems, including infections, says study author Chunjing Hu (Hongzhen Hu), a researcher from the school of medicine at the University of Washington .
As in humans, in mice with age starts itching. To find out the cause of the disease, Hu and his colleagues used thin nylon to affect a certain area of the shaved skin on the neck of young and old rodents.
Young individuals did not react to the touch, but the old rodents began furiously scratching this place.
While analyzing skin samples of mice from both groups, researchers found that older mice were present much less sensitive to pressure.
As the authors write the operation, the smaller Merkel cell of the animal, the more it suffered from the itching caused by the impact thread.
The team then the genetic way designed mice which did not have a Merkel cell, and then checked how rodents react to nylon fiber. It turned out that the mouse was furiously scratching at the affected area. According to scientists, the Cell of the Merchantive to suppress the itching sensations.
The experts also conducted another experiment in which increased activity of the Merkel cell. Geneticists have engineered the cell so that they respond to the impact of the chemical called clozapine N-oxide. The result is mice with less itching and scratching his skin.
The researchers suggested that the increase in the activity of Merkel cell can help people to cure allonnes.
Earlier studies have shown that Merkel cells in the skin. Hu and his colleagues are currently analyzing skin biopsies of people with itching caused by the touch. They want to understand whether in such samples, a fewer number of Merkel cell.
The study "well remember why people with dry skin or older people have better sensitivity to itching" says sinjun Dun (Xinzhong Dong), a neuroscientist from Johns Hopkins University. He was not involved in the study.
The authors noted that the results are still to be tested on humans. Meanwhile, the findings give hope for the development of the treatment of chronic itching in both young and elderly.
The results of the study are presented in the scientific journal Science.