Articles: hyperalgesia.
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Comparative Study
Potentiation of spinal N-methyl-D-aspartate-mediated nociceptive transmission by cocaine-regulated and amphetamine-regulated transcript peptide in rats.
The present study examined the effects of cocaine-regulated and amphetamine-regulated transcript peptide (CARTp) fragment 55-102, on N-methyl-D-aspartate (NMDA)-mediated nociceptive transmission in vivo and in vitro. In-vivo experiments were conducted in Sprague-Dawley rats to evaluate the effects of CARTp on thermal hyperalgesia induced by NMDA or alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA). Intrathecal NMDA (1, 2, 4 nmol) or AMPA (0.5, 1, 2 nmol) dose-dependently decreased the tail-flick latency. ⋯ The in-vitro effects of CARTp on NMDA-induced or AMPA-induced depolarizations in substantia gelatinosa neurons were studied in rat spinal cord slices. CARTp (100, 300 nM), which caused no significant change of membrane potentials, increased the amplitude of NMDA-induced depolarizations in substantia gelatinosa neurons with little effect on AMPA-induced depolarizations. The present study demonstrates that exogenously applied CARTp selectively facilitates NMDA receptor-mediated nociceptive transmission.
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Anaesth Intensive Care · Feb 2005
ReviewHigh-dose buprenorphine: perioperative precautions and management strategies.
Buprenorphine has been in clinical use in anaesthesia for several decades. Recently, the high-dose sublingual formulation (Subutex, Reckitt Benckiser, Slough, U. K.) has been increasingly used as maintenance therapy in opioid dependence, as an alternative to methadone and other pharmacological therapies. ⋯ Where pain may not be adequately relieved by these methods, the addition of a full opioid agonist such as fentanyl or morphine at appropriate doses should be considered, accompanied by close monitoring in a high dependency unit. In situations where this regimen is unlikely to be effective, preoperative conversion to morphine or methadone may be an option. Where available, liaison with a hospital-based alcohol and drug service should always be considered.
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Randomized Controlled Trial Comparative Study Clinical Trial
Intravenous dextromethorphan to human volunteers: relationship between pharmacokinetics and anti-hyperalgesic effect.
The aim of this study was to investigate the effect of dextromethorphan (DM) 0.5 mg/kg administered intravenously (i.v.) on hyperalgesia and pain after a tissue injury in human volunteers, and to describe the relationship between pharmacokinetic and pharmacodynamic data. The heat-capsaicin sensitisation model, a well-established experimental hyperalgesia model was induced in 24 healthy, male volunteers aged 21-35 years. The subjects received i.v. ⋯ The pharmacokinetic-pharmacodynamic relationship showed a large inter-subject variation with a mean delay in effect of nearly 2 h in relation to peak serum concentration. The results strongly indicate that DM is an anti-hyperalgesic drug. The delay in effect may be explained by several mechanisms and suggests that timing of DM administration is an essential factor for using the drug in clinical settings.
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Randomized Controlled Trial Comparative Study Clinical Trial
Rofecoxib attenuates both primary and secondary inflammatory hyperalgesia: a randomized, double blinded, placebo controlled crossover trial in the UV-B pain model.
The analysis of drug's influence on peripheral and central sensitisation can give useful information about its mode of action and can lead to more efficacy in the treatment of pain. Peripheral inflammation is associated with peripheral expression and up-regulation of cyclooxygenase 2 (COX-2) in the CNS. The relative contribution of COX-2 mediated central sensitisation may be prominent under inflammatory conditions. ⋯ No significant difference between the three dosage groups was observed. These data confirm peripheral effects of rofecoxib in a human inflammatory UV-B pain model and provide circumstantial evidence that even a standard clinical dose of rofecoxib reduces central hyperalgesia in inflammatory pain. We confirm that the effect of single oral dose of rofecoxib plateaus at 50 mg.
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Comparative Study
Spinal noradrenaline transporter inhibition by reboxetine and Xen2174 reduces tactile hypersensitivity after surgery in rats.
Spinal noradrenaline (NA) released in response to noxious stimuli may play an important role in suppression of nociceptive transmission. Here, we investigated the efficacy of a competitive NA transporter inhibitor (reboxetine) and a noncompetitive NA transporter inhibitor peptide, Xen2174, isolated from the Pacific cone snail, to treat tactile hypersensitivity following paw incisional surgery. Male Sprague-Dawley rats were anesthetized, an incision of the plantar aspect of the hind paw was performed, and withdrawal threshold to von Frey filaments near the surgical site determined. ⋯ The anti-hypersensitivity effect of 10 microg of Xen2174 was totally blocked by the alpha2-adrenoceptor antagonist, idazoxan, and partially blocked by the muscarinic antagonist, atropine. These data suggest that selective NA transporter inhibition suppresses post-incisional hypersensitivity through a different mechanism from that of neuropathic pain, since we previously reported that reversal of hypersensitivity by intrathecal clonidine, an alpha2-adrenoceptor agonist, following spinal nerve ligation is completely blocked by intrathecal atropine. Finally, these data suggest that intrathecal administration of Xen2174 at the time of spinal anesthesia might produce postoperative analgesia in humans.