Articles: hyperalgesia.
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Lysophosphatidic acid (LPA) is released from injured tissue and cancer cells and is involved in the induction of neuropathic pain. The present study explores whether LPA plays a role in the development of osteocarcinoma-induced pain. ⋯ These data indicate that LPA is involved in the induction of bone cancer pain through mechanisms of peripheral C-fibers sensitization. LPA and its downstream molecules possibly are promising therapeutic targets for treatment of cancer pain.
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Neuroscience letters · Jul 2010
Cyclooxygenase inhibitors suppress the expression of P2X(3) receptors in the DRG and attenuate hyperalgesia following chronic constriction injury in rats.
Recent evidence suggests that P2X(3) receptors express abundantly in nociceptive sensory neurons and play an important role in neuropathic pain. Upregulation of prostaglandin E2 (PGE2) after nerve injure is involved in the pathogenesis of neuropathic pain. An increase of P2X(3) receptors after chronic constriction injury (CCI) to the sciatic nerve has also been reported, the mechanisms are not known clearly. ⋯ The increase of P2X(3) receptors in the DRG in CCI rats on day 14 after surgery was also significantly inhibited; the effect of ibuprofen was stronger than that of celecoxib. These results demonstrate that up-regulated COX/PGE2 after nerve damage may play an important role in neuropathic pain. They are highly involved in the expression of P2X(3) receptors in the DRG in CCI rats.
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Clinical studies demonstrate attenuation of trigeminal-related pain states such as migraine by intranasal CO(2) application. This study investigated the underlying mechanisms of this observation and its potential use to reverse trigeminal pain and hypersensitivity. ⋯ Our results indicate that intranasal CO(2) application results in a subsequent attenuation of trigeminal nociception, mediated by protonic activation of TRPV(1) and ASIC channels. A potential central mechanism for this attenuation is discussed. The antihyperalgesic effects of intranasal CO(2) application might be useful for the treatment of trigeminal pain states.
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Review
Opioids, pain, the brain, and hyperkatifeia: a framework for the rational use of opioids for pain.
Opioids have relieved more human suffering than any other medication, but their use is still fraught with significant concerns of misuse, abuse, and addiction. This theoretical article explores the hypothesis that opioid misuse in the context of pain management produces a hypersensitivity to emotional distress, termed hyperkatifeia. ⋯ Repeated engagement of opponent processes without time for the brain's emotional systems to reestablish homeostasis will further drive changes in emotional processes that may produce opioid abuse or addiction, particularly in individuals with genetic or environmental vulnerability.
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Comparative Study
Comparison of a bupivacaine peripheral nerve block and systemic ketoprofen on peripheral inflammation and hyperalgesia in rats.
Local anaesthetics via a nerve block can attenuate inflammation. However, their effects have never been compared with the anti-inflammatory effects of systemic NSAIDs. The aim of this study was to compare the effects of bupivacaine via sciatic block with a systemic NSAID on oedema and hyperalgesia and on indices of systemic inflammation as measured by cytokines and prostaglandin E2 production in a model of peripheral inflammation in rats. ⋯ In the current study, a bupivacaine block alone achieved the same anti-inflammatory effect as systemic NSAID or as when the same block is combined with a NSAID.