Articles: hyperalgesia.
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Int J Clin Pract Suppl · Jul 2002
Randomized Controlled Trial Comparative Study Clinical TrialAnti-hyperalgesic effects of nimesulide: studies in rats and humans.
Nonsteroidal anti-inflammatory drugs (NSAIDs) are frequently used as analgesics. Despite the fact that clinical experience indicates a considerable disparity in the analgesic efficacy of NSAIDs, the animal models of nociception do not allow a clear distinction to be made between the analgesic properties of these agents. In contrast to nociceptive pain, clinical pain is characterised by hyperalgesia. ⋯ Moreover, nimesulide (100 mg) was significantly more effective than rofecoxib (25 mg). Overall, our data demonstrate that NSAIDs may show different anti-hyperalgesic properties. Nimesulide seems to be particularly effective and fast-acting against inflammatory pain.
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Comparative Study
Potent analgesic and anti-inflammatory actions of a novel thymulin-related peptide in the rat.
1. The present study examines the effect of PAT (peptide analogue of thymulin) in two rat models of inflammatory hyperalgesia induced by either i.pl. (1.25 microg in 50 microl saline) or i.p. (50 microg in 100 microl) injections of endotoxin ET. 2. Pretreatment with PAT (1, 5 or 25 microg in 100 microl saline, i.p.) decreased, in a dose dependent manner, both mechanical hyperalgesia, determined by the paw pressure (PP) test and thermal hyperalgesia determined by the hot plate (HP), the paw immersion (PI) and the tail flick (TF) tests. 3. ⋯ Pretreatment with PAT prevented the hyperalgesia and maintained the body temperature within the normal range and was accompanied by a down-regulation of the levels of pro-inflammatory cytokines and PGE(2) in the liver. 7. PAT, in all doses used, did not result in any evident changes in the physiological parameters or in the normal behaviour of the rats. 8. The anti-hyperalgesic and anti-inflammatory effects of PAT can be attributed, at least partially, to the down-regulation of pro-inflammatory mediators.
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The anticonvulsant gabapentin, proven effective for neuropathic pain in two large, placebo-controlled clinical trials, is widely used for treatment of chronic pain. Preclinical studies have demonstrated analgesic and antiallodynic effects in models involving neuronal sensitization and nerve injury, without affecting acute pain transmission. The aim of the present study was to link data from animal models and clinical trials for chronic pain by investigating the effect of gabapentin on acute nociception and experimentally induced cutaneous hyperalgesia in healthy volunteers. ⋯ The results link preclinical findings with results from clinical trials of neuropathic pain. The results further suggest that gabapentin may prove effective in acute pain disorders involving neuronal sensitization, such as postoperative pain and acute herpetic pain, and could prove effective in prevention of chronic pain.
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The aim of this study was to investigate a possible role for nerve growth factor (NGF) in the mechanism of pain and hyperalgesia induced by deep adenomyotic nodules and other forms of endometriosis and to clarify the relationship between endometriotic lesions and the surrounding nerves. ⋯ These results suggest a role of NGF in endometriotic pain and hyperalgesia in deep adenomyotic nodules. The strong expression of the NGF-TrkA pathway in deep adenomyotic nodules could explain why this type of lesion infiltrates in richly innervated anatomical sites.
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Two unilateral injections of pH 4.0 saline into the gastrocnemius muscle result in a bilateral decrease in mechanical withdrawal threshold after the second injection. This decrease is significant by 4h and lasts through 1 week. The purpose of this study was to characterize the involvement of both N-methyl-D-aspartate (NMDA) and non-NMDA glutamate receptors in the spinal cord dorsal horn in the development and maintenance of mechanical hyperalgesia from repeated intramuscular injections of acidic saline. 2-amino-5-phosphonovaleric acid (AP5) (2-20 nmol, 10 microl, pH 7) or 1,2,3,4-tetrahydro-6-nitro-2,3-dioxo[f]quinoxaline-7-sulfonamide (NBQX) (1-10 nmol, 10 microl, pH 8-9) was administered intrathecally to the lumbar spinal cord to block NMDA and non-NMDA ionotropic glutamate receptors in the dorsal horn, respectively. ⋯ Blockade of non-NMDA glutamate receptors in the spinal cord dorsal horn prior to either the first or second intramuscular injection of pH 4.0 saline had no effect on the development of mechanical hyperalgesia. However, spinal injection of NBQX 1 week after the second intramuscular injection of pH 4.0 saline resulted in an increase in mechanical withdrawal thresholds when compared to vehicle controls. These data suggest that both NMDA and non-NMDA glutamate receptors are involved in the maintenance of chronic, muscle-induced hyperalgesia.