Articles: hyperalgesia.
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Surgical removal of third molars may carry a risk of developing persistent orofacial pain, and central sensitization appears to play an important role in the transition from acute to chronic pain. ⋯ We found clear signs of sensitization of the trigeminal nociceptive system for at least one week after the surgery. Our results indicate that even a minor orofacial surgical procedure may be sufficient to evoke signs of both central and peripheral sensitization, which may play a role in the transition from acute to chronic pain in susceptible individuals.
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Anesthesia and analgesia · Jan 2008
The prolonged analgesic effect of epidural ropivacaine in a rat model of neuropathic pain.
In clinical practice, the analgesic effects of epidurally administered local anesthetics on chronic pain sometimes outlast the duration of drug action expected from their pharmacokinetics. To investigate the underlying mechanisms of this prolonged effect, we examined the effects of ropivacaine, a local anesthetic, on pain-related behavior in a rat model of neuropathic pain. We also analyzed changes in the expression of nerve growth factor (NGF), which is involved in plasticity of the nociceptive circuit after nerve injury. ⋯ Repetitive administration of ropivacaine into the epidural space in CCI rats exerts an analgesic effect, possibly by inducing a plastic change in the nociceptive circuit.
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J. Pharmacol. Exp. Ther. · Jan 2008
Intrathecal administration of proteinase-activated receptor-2 agonists produces hyperalgesia by exciting the cell bodies of primary sensory neurons.
Proteinase-activated receptors (PARs) are a family of G-protein-coupled receptors that are activated by endogenous serine proteinases that cleave the N-terminal domain of the receptor unmasking a "tethered ligand" sequence. Trypsin and other agonists at PAR(2) act on peripheral nerves to augment the transfer of nociceptive information. We tested whether PAR(2) agonists also exert a spinal pronociceptive effect by i.t. administering the selective ligand, Ser-Leu-Ile-Gly-Arg-Leu-NH(2) (SLI-GRL). ⋯ PAR(2)-like immunoreactivity was found in DRG but not in spinal dorsal horn. These results suggest that activation of DRG neuron cell bodies may account for the pronociceptive actions of i.t. applied PAR(2) agonists. They also imply that pathophysiological release of PAR(2)-activating proteases in the vicinity of DRG neurons may produce profound effects on nociceptive processing in vivo.
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Rev Esp Anestesiol Reanim · Jan 2008
Case Reports[Acute opiate tolerance and postoperative hyperalgesia after a brief infusion of remifentanil managed with multimodal analgesia].
Postoperative analgesia may be complicated by the occurrence of acute opiate tolerance and hyperalgesia. We present the case of a patient who underwent gynecological surgery that was complicated by intense pain in the immediate postoperative period. ⋯ Pain management with the usual dose of nonsteroidal anti-inflammatory drugs associated with a high dose of morphine (50 mg administered in less than 2 hours) produced no analgesic or adverse effects. The pain was finally brought under control by epidural perfusion of ropivacaine and fentanyl and subsequently maintained with multimodal analgesia.