Articles: opioid.
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Development of tolerance is a well known pharmacological characteristic of opioids and a major clinical problem. In addition to the known neuronal mechanisms of opioid tolerance, activation of glia has emerged as a potentially significant new mechanism. We studied activation of microglia and astrocytes in morphine tolerance and opioid-induced hyperalgesia in rats using immunohistochemistry, flow cytometry and RNA sequencing in spinal- and supraspinal regions. ⋯ No evidence for the activation of glia in the brain was seen. Our results suggest that glial activation associated with opioid tolerance and opioid-induced hyperalgesia occurs mainly at the spinal level. The transcriptome data suggest that the microglial activation pattern after chronic morphine treatment has similarities with that of neuropathic pain.
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Observational Study
Anxiety and its predictive value for pain and regular analgesic intake after lumbar disc surgery - a prospective observational longitudinal study.
Ongoing pain after surgery is a major problem and influences recovery and the quality of life of the patient. Associations between anxiety and their impact on postoperative pain after herniated disc surgery have been reported, but the results are inconsistent. The aim of the present longitudinal study was to evaluate the predictive value of preoperative anxiety for postoperative ongoing pain and prolonged analgesic intake after herniated disc surgery. ⋯ We found no evidence for the presence of anxiety before disc surgery being a prognostic factor for ongoing pain and regular postoperative intake of analgesics. Only preoperative pain intensity was predictive for increased pain and continued need for analgesic medication up to 6 months after lumbar disc surgery.