Scientists found men and women experience pain in very different ways, contrary to popular belief.
Most current research suggests men and women have different sensitivities to pain, but the common assumption has always been both sexes share a common pain circuit that is altered by gender-related hormones such as estrogen, the University of Alabama at Birmingham reported. A recent suggested this assumption may be false, and males and females actually use different biological systems to process pain.
"Realizing that females likely process pain differently than males will allow us to focus on creating alternate pain therapies for each sex," said researcher Robert Sorge, an assistant professor in the Department of Psychology in UAB's College of Arts and Sciences. "Females could respond better to a treatment that is different from what is prescribed for males - that's something we as researchers were not looking at before, and this study has helped us uncover that need."
Recent studies have shown theimmune system may play a larger role in pain responses than we thought, and actually works in tandem with the nervous system. Past experiments demonstrated the immune cell microglia is important for pain processing. When the cell is activated by an injury, it sounds an alarm by releasing a chemical that prompts neurons in the spinal cord to have a pain response.
The new findings reveal this process only naturally occurs in male mice, but has no effect in females. Instead, female mice's anatomy uses T cells to produce the same chemicals and illicit pain responses. The findings also show females can use the male system under certain circumstances
"Given that women greatly outnumber men as sufferers of chronic pain, one might wonder why it is that this sex difference was not noted until now," Sorge said. "The reason is that, as in most pain research, the overwhelming majority of the studies of microglia and pain were performed only on male rats and mice."
The U.S. National Institutes of Health has recently announced a new policy that requires female animals and cell lines to be used in preclinical research.
"The current findings from this paper are an excellent example of the wisdom of this policy," Sorge said. "Introducing female animals into research will ensure that we can identify problems and conditions that may be mechanistically differently in each sex."
The findings were published in a recent edition of the journal Nature Neuroscience.
