2024-07-05 08:04:29
It turns out that at the cellular level, men and women do indeed respond differently to painful stimuli. However, the answer to the question of which gender (if any) is more resistant to pain is not so simple.
In order for a person to feel pain, sensory neurons called nociceptors detect painful stimuli and send the signal to the brain, where it is interpreted. These painful stimuli include temperature extremes, mechanical pressure, and inflammation. People perceive each stimulus differently, and these differences are due to various factors, including a person’s gender.
According to several studies, women have a higher sensitivity to pain but a lower pain threshold than men. For example, in 2012 after the investigationwhich looked at how men and women respond to physical pressure, found that women are more sensitive to mechanical pain than men. During another study men and women were asked to indicate when they felt a heat stimulus and to rate its intensity. He showed that women have a lower pain threshold for heat than men.
“It’s well known that women are more sensitive to pain than men,” says Jeffrey Mogilas, a professor of behavioral neuroscience at McGill University in Canada, who studies gender differences in pain. – This has been proven in hundreds of human studies. Not all of them are statistically significant, but basically they all go in the same direction.”
However, some studies actually show the opposite.
in 2023 in a published study researchers conducted a thermal pain sensitivity test with 22 adolescent volunteers – 12 girls and 10 boys. These participants were exposed to hot and cold stimuli and asked to rate the intensity of the pain. Men rated higher pain intensity for both stimuli than women.
Still other studies showthat men and women do not differ in response to painful heat.
Scientists disagree on the lack of “meaningful” measures of pain tolerance, says Frank Porreca, a professor of neuroscience at the University of Arizona in the US. A given person’s pain threshold and tolerance tend to vary between trials and environments. In addition, according to some studies, women are more reliable test subjects than men because they rate their pain more consistently.
Porreca studies the mechanisms that can stimulate pain – and recently found with her team that nociceptors in men and women activated by different substances. This means that the first step in pain perception differs between the sexes.
J. Mogilas says that it was not previously proven that the properties of nociceptors themselves depend on gender.
It was known that pain stimuli must exceed certain thresholds to activate nociceptors. Normally, a mild stimulus – such as drinking cold water – does not activate the nociceptors, but if you have pain in your mouth, the nociceptors there are activated. In this case, the threshold for nociceptor activation is lowered, Porreca explained, and his team wanted to know if this “sensitization” was gender-specific.
To investigate this, the researchers took samples of nociceptor cells from the dorsal root ganglia, a site near the spinal cord through which sensory information enters the central nervous system. The research team took cells from male and female mice, non-human primates and humans – and exposed the cells to various substances.
Previous research has foundthat women’s reaction to pain depends on the hormone prolactin, and men’s response to pain — from a chemical messenger called orexin — so they seemed like perfect tools to do the experiment. The results showed that cells exposed to any of these substances behaved differently in all the species tested.
Prolactin lowered the nociceptor activation threshold in females but had no effect in males. Conversely, orexin sensitized male cells but had no effect on female cells. Both substances occur naturally in the body of both sexes, but in different concentrations.
“The nociceptors that we get from male, female or human donors (after death) are very different in terms of what processes lead to the lowering of thresholds,” says F. Porreca.
He added that the discovery could lead to the development of pain treatments that are optimally suited for men and women, especially given that “the majority of pain patients in the world are women.” For example, the chronic pain disease fibromyalgia, at least in the US women are more affected than men.
“Regardless of which gender is more sensitive to pain, there is growing evidence – for example in this paper – that different circuits operate behind the scenes in men and women,” says Mr Mogilas. “It’s actually a different system for men and women, and that’s actually the more interesting part.”
Parengta pagal „Live Science“.
2024-07-05 08:04:29