Opioids are the most prescribed drugs for the alleviation of pain. Both clinical and preclinical studies have reported strong evidence for sex-related divergence regarding opioid analgesia. There is an increasing amount of evidence indicating that gonadal hormones regulate the analgesic efficacy of opioids. This review presents an overview of the importance of gonadal steroids in modulating opioid analgesic responsiveness and focuses on elaborating what is currently known regarding the underlyingmechanism. We sought to identify the link between gonadal hormones and the effect of oipiod antinociception.
Keywords: Gonadal hormones; oestrogen; opioid; pain; progesterone; testosterone.
Gonadal hormones contribute to the sexual dimorphism of opioid antinociception.Generally, oestradiol is a negative modulator of opioid analgesia via both non-genomic and genomic effects.Testosterone facilitates opioid analgesia mainly through the transcriptional activities of androgen receptors.Under normal physiological conditions, progestin and oestrogen exist in parallel and have a combined effect. However, progestin alone could promote opioid analgesia by increasing the expression of opioid receptors.