A team of researchers from Massachusetts General Hospital (United States) has discovered that people with red hair have a naturally high tolerance to pain, due to a mechanism that increases their susceptibility to sunburn; that is, they present a greater activity of the opioid receptors involved in blocking pain and a decrease in the production of a type of hormones related precisely to sensitivity.
Thus, redheads – who have a genetic mutation in the melanocortin 1 receptor that prevents them from producing a dark pigment to tan and therefore makes their skin pale and practically impossible to tan – bear pain better than brunettes or blondes due to to melanocytes, which have been found to be essential in deciding a person’s pain threshold.
The bottom line is that redheads produce more opioid signals than people with other hair colors and therefore have a higher pain threshold.
Experiment
To investigate the mechanisms behind the different pain thresholds in red-haired individuals, the researchers studied a strain of red-haired mice that (as in humans) contains a variant that lacks the function of the melanocortin 1 receptor and also exhibits more pain thresholds. high. They found that the loss of melanocortin 1 receptor function in the red-haired mice caused the animals’ melanocytes to secrete lower levels of a molecule called POMC (proopiomelanocortin) that subsequently cuts into different hormones, including one that sensitizes pain and another that blocks pain. The presence of these hormones maintains a balance between opioid receptors that inhibit pain and melanocortin 4 receptors that improve pain perception.
“These findings describe the mechanistic basis behind previous evidence suggesting varied pain thresholds in different pigmentation backgrounds,” comments David E. Fisher in his study published in the journal Science Advances . “Understanding this mechanism provides validation of this prior evidence and valuable acknowledgment for medical personnel when caring for patients whose sensitivity to pain may vary.”
Although it was already known that humans, mice and specimens of other animal species with crimson or copper hair have a different tolerance to pain, these findings now allow us to know the processes and mechanisms that underlie the presence of various pain thresholds according to their pigmentation history. This could lead to the development of new drugs that inhibit the melanocortin 4 receptors involved in the detection of pain as a new way to control the perception of pain.
“Our ongoing work is focused on elucidating how additional skin-derived signals regulate pain and opioid signaling,” says Lajos V. Kemény, a co-author of the study. “Understanding these pathways in depth can lead to the identification of new pain modulating strategies .”
Referencia: Reduced MC4R signaling alters nociceptive thresholds associated with red hair. David E. Fisher, Kathleen C. Robinson et al. Science Advances (2021).DOI:https://doi.org/10.1126/sciadv.abd1310
