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In fact, humans have only 5 types of natural hair color, of which the most common is black, accounting for about 80% of the total global population, followed by brown, then yellow, silver and color. red .
People with red hair are rare, they are mainly Celtic people of Scotland and Ireland, and they make up less than 2% of the total global population. Jonathan Rhys, a professor of dermatology at the University of Edinburgh, UK, thinks that this hair color is an evolutionary accident, not through natural selection (although two Neadertal men have been found. ancient in two distant regions and in two different periods but with the same hair color, showing that red hair is not necessarily random).
In red-haired humans (and red-haired animals), the pigment-producing melanocytes in their skin carry a mutation in the melanocorticoid receptor-1 (MC1R) gene. Melanocortin receptor-1 is located on the cell surface. And during sun exposure, melanocortin activates the melanocortin-1 receptor, causing melanocytes to produce more eumelanin, resulting in darker and tanned skin, while MC1R causes those people with red hair have a genetic mutation and are more sensitive to ultraviolet rays. The International Journal of Cancer reported in 2010 that people with naturally red hair are about two and a half times more likely to develop dangerous cancers than people with other hair colors.
People with naturally red hair also have a higher baseline pain threshold than others, which means they are less afraid of pain, better able to tolerate pain, and this also makes them more sensitive. than with opioid analgesics.
Recently, researchers at Harvard Medical School’s Massachusetts General Hospital published a research paper titled, “Reducing MC4R signaling alters red hair-related perceptual thresholds” in the journal Science. Advances.
This study revealed the mechanism of action of melanocorticoid receptor-1 (MC1R) and promelanocortin (POMC) in raising pain threshold in redheads, and also showed that inhibiting melanocorticoid receptor- 4 (MC4R) can inhibit pain and propose a new approach to human pain management.
To investigate the mechanism behind the different pain thresholds in individuals with red hair color in humans and red hair in animals, the researchers used a line of red-haired mice that, like humans, have red feathers due to mutations in the MC1R gene, and also has a higher than usual pain threshold.
The team found that mutations in the MC1R gene in red-haired mice cause their melanocytes to secrete lower levels of promelanocortin (POMC), which is then broken down into different hormones, including one pain-sensitive hormone and a pain-blocking hormone. The presence of these hormones maintains a balance between pain-relieving opioid receptors and pain-relieving melanocorticoid-4 receptors (MC4Rs).
In red-haired mice, the two hormones seem to oppose each other in low amounts, but in humans the body also makes other factors unrelated to melanocyte to activate pain-blocking opioid receptors.
Collectively, this study elucidates the mechanism of action of melanocorticoid receptor-1 (MC1R) and promelanocortin (POMC) in the elevated pain threshold in redheads, and also suggests that inhibiting the melanocorticoid hormone Receptor- 4 (MC4R) can inhibit pain and propose a new approach to human pain management.
References: Science Advances; RD; ZME
#people #red #hair #tolerance #pain