SUNY Downstate Medical Center Logo Not many of us may be aware that men and women have different sensitivity to pain. This is precisely the reason why the effect of painkillers varies with sex. As per scientists at State University of New York (SUNY) Downstate Medical Center, some basic kinds of opioid receptors that transfer pain sensations respond differently in men and women.

Female lab creatures were known to apparently comprise nearly five folds of additional kappa-mu heterodimer than their male counterparts. Moreover, when women possessed high levels of estrogen and progesterone, the proportion of this ingredient was seemingly quadrupled. This moved the scientists to conclude that estrogen and progesterone are supposedly crucial for the formation of mu-kappa opioid receptor heterodimers.

Medicines such as pentazocine, nalbuphine, and butorphanol are known to rely on the aforesaid constituent, therefore they seem to work more with females than males. If kappa-opioid receptor is activated within the kappa-opioid receptor complex it supposedly paves way for the pain relieving mechanism of the receptors leaving their pain-supporting functions untouched.

“This consideration could become even more critical in managing pain in postmenopausal and elderly women. Further research is needed to flesh out these possibilities,” commented Alan Gintzler, PhD, professor of biochemistry, Department of Obstetrics and Gynecology, at the State University of New York (SUNY) Downstate Medical Center.

The findings reveal that kappa-mu opioid receptor heterodimers may have the potential to work as a molecular switch that transits responses of kappa-opioid receptors and endogenous chemicals that seem to reduce pain rather than supporting it. As per the investigators, Kappa-mu opioid receptor heterodimers could be used as a new molecular target for the purpose of pain management in females. As per the researchers, doctors ought to consider the menstruation phase of women before referring any sort of drug. Some medicines tend to lower pain during these times, while some may elevate pain when the levels of estrogen are low.

The article is published in the Proceedings of the National Academy of Sciences and the Journal of Neuroscience.