It is known that females are more likely to experience chronic pain and poorly respond to the treatment than males. Some researchers have proposed these gender differences due to estrogens. However, a new study shows that these gender differences are more likely due to testosterone. In the study, researchers found that higher testosterone levels were associated with higher anesthetic responses.
This study sheds new light on the long-known topic. It helped identify new underlying mechanisms, which may ultimately help doctors better treat chronic pain in female patients.
It is no secret that females are prone to mood and emotional disorders, and they are more likely to experience chronic pains. One of the reasons for higher pain sensitivity in females has been proposed is due to estrogens. However, there has been a lesser focus on testosterone.
But what if this higher pain sensitivity in females is rather due to lower testosterone levels compared to males? This new study, at least, seems to suggest that.
Of course, differences in pain sensitivities are also due to differences in brain structures between the genders. However, these differences also have a lot to do with hormonal differences.
One more thing is worth understanding: females have testosterone in their body, but its levels are several times lower than males.
However, the problem is not only limited to higher pain sensitivity in females. They are also less sensitive to certain painkillers.
A Study Shows That Females Less Commonly Used Anesthetics Due to Lower Testosterone Levels
Researchers at the University of Pennsylvania, Philadelphia, did this new study. The researchers carried out a study in mice. They tested them for sensitivity to anesthetics like isoflurane, sevoflurane, halothane, and desflurane.
They had many interesting findings and unexpected ones. Thus, for example, females needed almost 25% greater dosage of isoflurane for the induction of anesthesia. Further, they also found that females woke up much faster after the anesthesia than males. In fact, many females woke up at the dosage that would be enough to knock out male mice. So, yes, this difference is massive among the genders. It shows that females are less sensitive to anesthetics. This effect was seen with all the four drugs used in the experiment.
Not only did females regain consciousness faster, but they also became aware much faster. Researchers stuck the adhesive stickers on the snouts of mice. They found that female mice started removing this sticker after 242 seconds on average, while male mice only after 483 seconds. Again, there is a massive difference.
However, the above findings still do not confirm if these differences are due to estrogen or testosterone.
Hence, in the next experiment phase, researchers castrated male mice. They also found that male mice became more resistant to anesthetics due to reduced testosterone levels. However, no such effect was seen after removing ovaries from female mice. This confirms that testosterone, not estrogens, considerably influences sensitivity to anesthetics.
Researchers also noticed that traditional EEG is not useful in understanding these differences. Hence, they also used full brain scans to see why these differences exist. They found that the female hypothalamus had fewer active neurons in the sleep-inducing region.
Researchers also carried out a small study on 30 human subjects. They found that males were slower to regain full attention after the anesthesia than females.
The Bottom Line
This study did add something new to the existing knowledge. Although it is long known that females are less sensitive to anesthetics and painkillers, this study confirmed that these differences are due to testosterone levels. Of course, differences between males and females also contribute to this, but those differences result from hormonal differences between the genders. Further, this study also showed that full brain scans are better than regular EEGs for understanding these differences. If you are dealing with chronic pain issues, you may visit Padda Institute for expert consultation and personalized treatment.
Source:
Wasilczuk, A. Z., Rinehart, C., Aggarwal, A., Stone, M. E., Mashour, G. A., Avidan, M. S., Kelz, M. B., & Proekt, A. (n.d.). Hormonal basis of sex differences in anesthetic sensitivity. Proceedings of the National Academy of Sciences of the United States of America, 121(3), e2312913120. https://doi.org/10.1073/pnas.2312913120
