alexsamuel
Matrose
Joined: 14 October 2019
Location: United States
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| Posted: 09 March 2020 at 06:32 | IP Logged
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Brazilian and American scientists confirm a well-known theory: that stress or anxiety gives white hair. Their study, conducted in mice, describes the precise mechanisms of a phenomenon as scary as it is intriguing.
We now know why hair can bleach under stress
In addition to confirming that stress release via physio can actually give us gray hair, this work opens up avenues to learn more about how stress influences our body's reactions.
" Stop getting white hair "! Here is a common expression of the French language which illustrates, literally and figuratively, a purely biological phenomenon. The theory that an emotionally traumatic episode or a period of intense stress can cause favorites to turn gray is indeed widespread.
" But so far, this link has not been validated scientifically ", underline the researchers behind this new work published in the journal Nature . Through what mechanisms does this curious hair discoloration occur?
To unravel this mystery, the study authors tested this theory on laboratory mice. Rodents have been subjected to distinct intense stress situations. Each stressor has led to the appearance of gray / white hairs in animals.
A neurotransmitter involved
The researchers then attacked the melanocyte stem cells, located in the bulge of the hair follicle, the cavity that serves as the basis for hair growth. The action of these cells is innervated by the neurons of the sympathetic nervous system which in turn releases the neurotransmitter molecule noradrenaline, under the effect of stress or fear. Once activated, this molecule produces an effect on the melanocyte stem cells, which are responsible for the pigmentation of hair.
Normally, these stem cells remain inactive until hair regrowth is necessary. But if the melanocyte stem cells are depleted, the action of pigmentation of the hair roots is not triggered. Consequence: the hair is irreversibly whitening.
To test this theory and try to counter these effects, the researchers administered treatment for high blood pressure to block the action of norepinephrine, which prevented gray / white hair from appearing in the mice.
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Topic: Why Hairs can Bleach under Stress?
