Articles: hyperalgesia.
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Randomized Controlled Trial
[Modulation of cortical pain processing by cyclooxygenase inhibition: a functional MRI study].
Little is known about changes in brain activity with pharmacological modulation of hyperalgesia. Therefore, we sought to investigate the cerebral processing of hyperalgesia and acute pain using functional magnetic resonance imaging (fMRI) and pharmacological modulation with cyclooxygenase (COX) inhibitors. ⋯ This study provides new evidence for the involvement of COX inhibitors in modulating the cerebral activity associated with acute pain and hyperalgesia. Our results hint at a differential modulation of brain areas under either analgesia or antihyperalgesia.
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Anesthesia and analgesia · Apr 2009
Antiinflammatory and antihyperalgesic activity of C-phycocyanin.
C-phycocyanin (C-PC), a biliprotein found in blue green algae, such as Spirulina platensis, is often used as a dietary nutritional supplement due to its various therapeutic values. In addition, the antiinflammatory activity of C-PC partly through inhibition of proinflammatory cytokine formation, inducible nitric oxide synthase (iNOS) and cyclooxygeanase-2 (COX-2) expression has been demonstrated in many in vitro and in vivo studies. However, whether C-PC also has antihyperalgesic activity in inflammatory nociception has not been investigated. ⋯ Based on these results, it is suggested that the inhibition of NO and prostaglandin E(2) over-production through suppressing iNOS and COX-2 induction and attenuation of TNF-alpha formation and neutrophil infiltration into inflammatory sites by C-PC may contribute, at least in part, to its antihyperalgesic activity.
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Endothelins, acting through specific endothelin ET(A) and/or ET(B) receptors, participate in nociceptive processing in models of cancer, inflammatory and neuropathic pain. The present study investigated which cell types express endothelin receptors in the trigeminal ganglion, and the contribution of mechanisms mediated by endothelin ET(A) and ET(B) receptors to orofacial heat hyperalgesia induced by unilateral constriction of the infraorbital nerve (CION). Both receptor types were identified by immunohistochemistry in the trigeminal ganglion, ET(A) receptors on small-sized non-myelinated and myelinated A-fibers and ET(B) receptors on both satellite glial cells and small-sized non-myelinated neuronal cells. ⋯ On the other hand, CION-induced heat hyperalgesia was transiently abolished over the first 90 min following i.p. injection of morphine hydrochloride (2.5 mg/kg), but fully resistant to reversal by indomethacin (4 mg/kg, i.p.) or celecoxib (10 mg/kg, i.p.). Thus, heat hyperalgesia induced by CION is maintained, in part, by peripheral signaling mechanisms operated by ET(A) and ET(B) receptors. Endothelin receptors might represent promising therapeutic targets for the control of trigeminal neuropathic pain.
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J. Gastroenterol. Hepatol. · Apr 2009
Antinociceptive effect of chronic lithium on visceral hypersensitivity in a rat model of diarrhea-predominant irritable bowel syndrome: The role of nitric oxide pathway.
Lithium, a widely used drug in bipolar-affective disorders, plays gastro-protective roles. The effects of lithium on several tissues are mediated through nitric oxide (NO), which regulates gastrointestinal motility and mucosal integrity. The aim of this study was to investigate the protective effect of chronic lithium administration on visceral hypersensitivity and to investigate the role of NO as a potential mechanism of lithium in a rat model of irritable bowel syndrome. ⋯ The results indicate the antinociceptive property of chronic lithium on visceral hypersensitivity. As this effect was lowered by NOS inhibitors, NO might play a role in the protective effect of lithium to some extent.
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Letter Case Reports
Opioid-induced hyperalgesia in a patient with dementia.