Articles: hyperalgesia.
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Up-regulation of P2X4 receptors in spinal cord microglia is crucial for tactile allodynia, an untreatable pathological pain reaction occurring after peripheral nerve injury. How nerve injury in the periphery leads to this microglia reaction in the dorsal horn of the spinal cord is not yet understood. It is shown here that CCL21 was rapidly expressed in injured small-sized primary sensory neurons and transported to their central terminals in the dorsal horn. ⋯ A single intrathecal injection of CCL21 to nerve-injured CCL21-deficient mice induced long-lasting allodynia that was undistinguishable from the wild-type response. This effect of CCL21 injection was strictly dependent on P2X4 receptor function. Since neuronal CCL21 is the earliest yet identified factor in the cascade leading to tactile allodynia, these findings may lead to a preventive therapy in neuropathic pain.
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Anesthesia and analgesia · May 2011
Central and local administration of Gingko biloba extract EGb 761® inhibits thermal hyperalgesia and inflammation in the rat carrageenan model.
Oral administration of the standardized Ginkgo biloba extract EGb 761® has been shown to inhibit thermal hyperalgesia in rodent models of inflammatory and postsurgical pain, but the mechanism underlying these effects is not known. We sought to determine the site of action of EGb 761 by investigating the antihyperalgesic and antiinflammatory properties of EGb 761 after local and central drug administration in the rat carrageenan model of inflammation. ⋯ These studies show that EGb 761 acts both at the site of inflammation and centrally at the spinal cord level to inhibit inflammation and thermal hyperalgesia, and may be useful in the treatment of inflammatory pain.
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Reg Anesth Pain Med · May 2011
Randomized Controlled Trial Comparative StudyS-ketamine modulates hyperalgesia in patients with chronic pancreatitis pain.
Upper abdominal pain is a dominant feature of chronic pancreatitis. A key phenomenon in this context is hyperalgesia, typically associated with N-methyl-d-aspartate receptor activation. This exploratory study evaluates acute effects of S-ketamine, a noncompetitive N-methyl-d-aspartate antagonist, in modulating generalized hyperalgesia in chronic pancreatitis pain. ⋯ S-ketamine infusion is more effective than placebo in increasing PPTs in chronic pancreatitis pain patients immediately after infusion. This effect did not outlast the infusion. Further research is warranted into S-ketamine use for reducing generalized hyperalgesia and chronic pancreatitis pain.
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Gabapentin is an anticonvulsant and adjuvant analgesic. It is effective in several pain studies. Neuropathic pain is the most difficult type of pain to treat. In this study, we examined if intrathecal gabapentin could prevent nerve injury-induced pain. ⋯ We showed a preventative effect of intrathecal gabapentin on the development of nerve injury-induced mechanical allodynia and thermal hyperalgesia. Our data suggest that continuous intrathecal gabapentin may be considered as an alternative for the prevention of nerve injury-induced pain.
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Randomized Controlled Trial
Ondansetron, a 5HT3-antagonist, does not alter dynamic mechanical allodynia or spontaneous ongoing pain in peripheral neuropathy.
The aim of this study was to examine whether the intensity of dynamic mechanical allodynia and spontaneous ongoing pain in patients with neuropathic pain associated with peripheral neuropathy was influenced by an intravenous infusion of the 5HT3-antagonist, ondansetron. ⋯ No influence from 8 mg of ondansetron could be shown on the intensity of brush-evoked or spontaneous ongoing pain in patients with peripheral neuropathy, indicating the lack of involvement of 5HT3-receptors in an earlier proposed spinobulbospinal loop with descending facilitation acting on spinal mechanisms related to dynamic mechanical allodynia.