Articles: hyperalgesia.
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Pharmacogenet. Genomics · Nov 2006
Genetic variants of the P-glycoprotein gene Abcb1b modulate opioid-induced hyperalgesia, tolerance and dependence.
Opioid-induced hyperalgesia (OIH) is a state of paradoxically increased nociceptive sensitivity seen in both humans and rodents following the resolution of the acute opioid antinociceptive effects or during periods of chronic opioid administration. Using the power of genetic analysis, we hoped to discover novel mechanisms modulating this trait. ⋯ We conclude that the use of haplotypic mapping to identify novel mechanisms controlling complex traits is a viable approach. Variants of the Abcb1b gene may explain some portion of the interstrain differences in OIH and perhaps other consequences of chronic opioid administration.
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The activation of spinal cord microglia and astrocytes after peripheral nerve injury or inflammation contributes to behavioral hypersensitivity. The contribution of spinal cord glia to mechanical hypersensitivity after hind paw incision has not been investigated previously. Male Sprague-Dawley rats underwent a unilateral plantar hind paw incision, and the development of mechanical hypersensitivity was assessed by using von Frey filaments. The activation of spinal cord microglia and astrocytes was measured 1, 2, 3, and 5 days after hind paw incision by using immunohistochemistry. The glial activation inhibitor, fluorocitrate, was administered intrathecally 24 hours after hind paw incision to determine glial involvement in mechanical hypersensitivity. Hind paw incision induced an activation of spinal astrocytes ipsilateral to incision within 24 hours. Both microglia and astrocytes reached a maximum activation 3 days after hind paw incision. Fluorocitrate produced a dose-dependent reduction in mechanical hypersensitivity when administered 24 hours after hind paw incision. Spinal cord glial activation contributes to the mechanical hypersensitivity that develops after hind paw incision. ⋯ Hind paw incision produces mechanical hypersensitivity that can be alleviated with the inhibition of spinal cord glia. Our results suggest that the activation of spinal cord astrocytes within 24 hours of incision contributes to mechanical hypersensitivity. Therefore, spinal cord astrocytes might represent a novel target for the treatment of postoperative pain.
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Fertility and sterility · Nov 2006
Clinical TrialPain, mast cells, and nerves in peritoneal, ovarian, and deep infiltrating endometriosis.
To detect and quantify mast cells in peritoneal, ovarian, and deep infiltrating endometriosis and to study the relationship between mast cells and nerves in endometriosis. ⋯ The presence of increased activated and degranulating mast cells in deeply infiltrating endometriosis, which are the most painful lesions, and the close histological relationship between mast cells and nerves strongly suggest that mast cells could contribute to the development of pain and hyperalgesia in endometriosis, possibly by a direct effect on nerve structures.
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Spinally released dynorphin contributes to hypersensitivity from nerve injury, inflammation, and sustained morphine treatment, but its role in post-operative pain has not been tested. Intrathecal injection of dynorphin activates cyclooxygenase (COX)-1 and -2 to induce hypersensitivity. Spinal COX-1 expression and activity increase following incisional paw surgery in rats, although the stimulus for this increase is not known. ⋯ Spinal cord microglia in culture expressed COX-1 immunoreactivity and released PGE2, but dynorphin A failed to increase release of PGE2 in these cultures. These results suggest that increased COX-1 expression occurs in spinal cord microglia following incisional surgery. Although prodynorphin immunoreactivity also increases, it likely does not drive COX-1 expression or mechanical hypersensitivity in this setting.
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Anasthesiol Intensivmed Notfallmed Schmerzther · Nov 2006
Case Reports[Post-operative pain therapy of a chronic pain patient].
Post-operative pain therapy of chronic pain patients poses a challenge. Here we report the perioperative management of a 39-year-old male under chronic therapy with oxycodon, gabapentin and tolperison. Particular the pharmacointeractions regarding premedication and postoperative dose finding of opioids with intravenous PCIA are discussed.