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Medical AI Inquiry: You was designed to assist in medical decision-making based on the provided user questions. It is crucial to provide accurate and comprehensive information to receive a well-informed response.  Labels: BACKGROUND, METHODS, RESULTS. Meshes: Analgesics, Opioid, Animals, Anti-Inflammatory Agents, Non-Steroidal, Cell Line, Cytokines, Drug Synergism, Drug Tolerance, Female, Glucosides, Humans, Macrophage Activation, Male, Mice, Microglia, Monoterpenes, Morphine, NF-kappa B, Pain Measurement, Rats, Rats, Sprague-Dawley, Signal Transduction, Spinal Cord, p38 Mitogen-Activated Protein Kinases.
user
Does selective suppression of microglial activation by paeoniflorin attenuate morphine tolerance? Context: The development of antinociceptive tolerance following repetitive administration of opioid analgesics significantly hinders their clinical use. Evidence has accumulated indicating that microglia within the spinal cord play a critical role in morphine tolerance. The present study investigated the effects and possible mechanisms of a natural compound, paeoniflorin, in morphine tolerance via its specific inhibition of microglial activation. The microglia cell line BV-2 was used. Cytokine expression was measured using quantitative polymerase chain reaction. Cell signalling was assayed by Western blot and immunohistochemistry. Nociception was assessed in Sprague-Dawley rats and CD-1 mice using Hargreaves' methods or the hot-plate test, respectively. (1) Morphine induces robust BV-2 cell activation, as evidenced by increased p38 mitogen-activated protein kinase (MAPK) phosphorylation, nuclear factor (NF)-κB translocation and proinflammatory cytokine expression. These changes are inhibited by paeoniflorin. (2) Co-administration of paeoniflorin with morphine potentiates morphine antinociception by inhibiting p38 MAPK/NF-κB signalling in the spinal cord. (3) Co-administration of paeoniflorin suppresses morphine-increased expression of toll-like receptor-4 both in BV-2 cells and within the spinal cord following chronic morphine treatment.
assistant
Paeoniflorin directly suppresses morphine-induced microglial activation and thus results in potentiation of morphine acute analgesia and attenuation of morphine chronic antinociceptive tolerance. Final Decision: yes