Sex differences in opioid analgesia and addiction: interactions among opioid receptors and estrogen receptors
1 Center for Drug Abuse and Addiction, China Medical University Hospital, 2 Yuh-Der Road, Taichung 40447, Taiwan
2 China Medical University, Taichung, Taiwan
3 Graduate Institute of Clinical Medical Science, China Medical University, Taichung, Taiwan
4 Center for Neuropsychiatric Research, National Health Research Institutes, Zhunan, Miaoli County, Taiwan
Molecular Pain 2013, 9:45 doi:10.1186/1744-8069-9-45Published: 8 September 2013
Opioids are widely used as the pain reliever and also notorious for being addictive drugs. Sex differences in the opioid analgesia and addiction have been reported and investigated in human subjects and animal models. Yet, the molecular mechanism underlying the differences between males and females is still unclear. Here, we reviewed the literature describing the sex differences in analgesic responses and addiction liabilities to clinically relevant opioids. The reported interactions among opioids, estrogens, opioid receptors, and estrogen receptors are also evaluated. We postulate that the sex differences partly originated from the crosstalk among the estrogen and opioid receptors when stimulated by the exogenous opioids, possibly through common secondary messengers and the downstream gene transcriptional regulators.