Different people handle pain differently. Some go screaming after the most minor paper cut while others can even handle a stabbing. Now, scientists may have found an answer to why people have such different thresholds of pain after studying our ancestors.
Pain is mediated through specialized nerve cells that exhibit an ion channel that is key to triggering the electrical impulse that signals pain to the brain. According to the new study, individuals who inherit the Neanderthal variant of this ion channel have a lower threshold for pain.
As several Neanderthal genomes are available today, researchers can study their historical physiological effects and look into their modern-day consequences. Looking into such one gene, the researchers found that some people, especially from Central and South America but also in Europe, inherited a Neanderthal variant of the gene that causes them to experience higher levels of pain.
The study oversaw a huge population in the UK and found that those who carried the Neanderthal variant of the ion channel had a lower threshold for pain.
"The biggest factor for how much pain people report is their age. But carrying the Neanderthal variant of the ion channel makes you experience more pain similar to if you were eight years older," said lead author Hugo Zeberg, a researcher at the Max Planck Institute for Evolutionary Anthropology and Karolinska Institutet.
According to Zeberg, the Neanderthal variant of the ion channel can be identified because it carries three amino acid differences to the more common variant. These three amino acid substitutions lead to heightened pain sensitivity in carriers.
On a molecular level, the Neanderthal ion channel is also more easily activated leading to more pain. The researchers state that it is unclear whether Neanderthals experienced more pain because pain is also modulated both in the spinal cord and in the brain. However, the study does indicate that their threshold for pain would have been lower than in most present-day humans.
The findings are published in the journal Current Biology.