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Sex Differences In Mu-Opioid Receptor Expression In The Rat Midbrain Periaqueductal Gray Are Essential For Eliciting Sex Differences In Morphine Analgesia, Dayna R. Loyd, Xioaya Wang, Anne Z. Murphy Phd
Sex Differences In Mu-Opioid Receptor Expression In The Rat Midbrain Periaqueductal Gray Are Essential For Eliciting Sex Differences In Morphine Analgesia, Dayna R. Loyd, Xioaya Wang, Anne Z. Murphy Phd
Neuroscience Institute Faculty Publications
Opioid-based narcotics are the most widely prescribed therapeutic agent for the alleviation of persistent pain; however, it is becoming increasingly clear that morphine is significantly less potent in women compared with men. Morphine primarily binds to mu-opioid receptors (MORs), and the periaqueductal gray (PAG) contains a dense population of MOR-expressing neurons. Via its descending projections to the rostral ventromedial medulla and the dorsal horn of the spinal cord, the PAG is considered an essential neural substrate for opioid-based analgesia. We hypothesized that MOR expression in the PAG was sexually dimorphic, and that these sex differences contribute to the observed sex …
Sexually Dimorphic Activation Of The Periaqueductal Gray – Rostral Ventromedial Medullary Circuit During The Development Of Morphine Tolerance In The Rat, Dayna R. Loyd, Michael M. Morgan, Anne Z. Murphy Phd
Sexually Dimorphic Activation Of The Periaqueductal Gray – Rostral Ventromedial Medullary Circuit During The Development Of Morphine Tolerance In The Rat, Dayna R. Loyd, Michael M. Morgan, Anne Z. Murphy Phd
Neuroscience Institute Faculty Publications
Previous studies have shown that tolerance develops to a greater degree in male compared to female rats. The midbrain periaqueductal gray (PAG), and its descending projections to the rostral ventromedial medulla (RVM), provides an essential neural circuit for the antinociceptive effects of opiates and has been implicated in the development of tolerance to morphine. We have previously reported that systemic morphine administration activates a greater proportion of PAG-RVM neurons in male versus female rats; our hypothesis is that if the PAG-RVM pathway is essential for the development of morphine tolerance, then (1) morphine activation of the PAG-RVM pathway should decline …
Androgen And Estrogen (Α) Receptor Localization On Periaqueductal Gray Neurons Projecting To The Rostral Ventromedial Medulla In The Male And Female Rat, Dayna R. Loyd, Anne Z, Murphy Phd
Androgen And Estrogen (Α) Receptor Localization On Periaqueductal Gray Neurons Projecting To The Rostral Ventromedial Medulla In The Male And Female Rat, Dayna R. Loyd, Anne Z, Murphy Phd
Neuroscience Institute Faculty Publications
The periaqueductal gray (PAG) is involved in many gonadal steroid-sensitive behaviors, including responsiveness to pain. The PAG projects to the rostral ventromedial medulla (RVM), comprising the primary circuit driving pain inhibition. Morphine administered systemically or directly into the PAG produces greater analgesia in male compared to female rats, while manipulation of gonadal hormones alters morphine potency in both sexes. It is unknown if these alterations are due to steroidal actions on PAG neurons projecting to the RVM. The expression of androgen (AR) and estrogen (ERα) receptors in the PAG of female rats and within this descending inhibitory pathway in both …