https://www.selleckchem.com/products/puromycin-aminonucleoside.html Evaluation of mRNA expression showed the transcripts for both receptors were co-localized in cells in the dorsal horn of the lumbar spinal cord and dorsal root ganglia. Thus, MMG22 reduces hyperalgesia after injury in the SNI model of neuropathic pain without the typical centrally mediated side effects associated with traditional opioids.Withdrawal from systemic opioids can induce long-term potentiation (LTP) at spinal C-fibre synapses ("opioid-withdrawal-LTP"). This is considered to be a cellular mechanism underlying opioid withdrawal-induced hyperalgesia, which is a major symptom of the opioid withdrawal syndrome. Opioids can activate glial cells leading to the release of pro-inflammatory mediators. These may influence synaptic plasticity and could thus contribute to opioid-withdrawal-LTP. Here, we report a sexual dimorphism in the mechanisms of morphine-withdrawal-LTP in adult rats.We recorded C-fibre-evoked field potentials in the spinal cord dorsal horn from deeply anaesthetised male and female rats. In both sexes we induced a robust LTP via withdrawal from systemic morphine infusion (8 mg·kg bolus, followed by a one-hour infusion at a rate of 14 mg·kg·h). This paradigm also induced mechanical hypersensitivity of similar magnitude in both sexes. In male rats, systemic but not spinal application of (-)naloxone blocked the induction of morphine-withdrawal-LTP, suggesting the involvement of descending pro-nociceptive pathways. Furthermore, we showed that in male rats, the induction of morphine-withdrawal-LTP required the activation of spinal astrocytes and the release of the pro-inflammatory cytokines tumour necrosis factor (TNF) and interleukin-1 (Il-1). In striking contrast, in female rats, the induction of morphine-withdrawal-LTP was independent of spinal glial cells. Instead, blocking µ-opioid receptors in the spinal cord was sufficient to prevent a facilitation of synaptic strength.Our study