Articles: hyperalgesia.
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The UVB and heat rekindling (UVB/HR) model shows potential as a translatable inflammatory pain model. However, the occurrence of central sensitization in this model, a fundamental mechanism underlying chronic pain, has been debated. Face, construct and predictive validity are key requisites of animal models; electromyogram (EMG) recordings were utilized to objectively demonstrate validity of the rat UVB/HR model. ⋯ This study used objective outcome measures of secondary hyperalgesia to validate the rat UVB/HR model as a translational model of inflammatory pain.
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Extracellular high mobility group box-1 protein (HMGB1) plays important roles in the pathogenesis of nerve injury- and cancer-induced pain. However, the involvement of spinal HMGB1 in arthritis-induced pain has not been examined previously and is the focus of this study. Immunohistochemistry showed that HMGB1 is expressed in neurons and glial cells in the spinal cord. ⋯ Furthermore, the pro-nociceptive effect of i.t. injection of HMGB1 persisted in Tlr2- and Rage-, but was absent in Tlr4-deficient mice. The same pattern was observed for HMGB1-induced spinal microglia and astrocyte activation and cytokine induction. These results demonstrate that spinal HMGB1 contributes to nociceptive signal transmission via activation of TLR4 and point to disulfide HMGB1 inhibition as a potential therapeutic strategy in treatment of chronic inflammatory pain.
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Arthritis Rheumatol · Sep 2014
Contribution of transient receptor potential ankyrin 1 to chronic pain in aged mice with complete Freund's adjuvant-induced arthritis.
To investigate age-related differences in mechanical sensitivity to inflammatory pain and determine the contribution of transient receptor potential ankyrin 1 (TRPA1) to mechanical hypersensitivity during chronic inflammation in young and aged mice with complete Freund's adjuvant (CFA)-induced arthritis. ⋯ These findings reveal marked differences in the long-term mechanical behavioral sensitivity of aged and young mice, and suggest that TRPA1 may be a key contributor to the transition from acute to chronic inflammatory pain in response to mechanical stimuli as well as to the development of nociceptor sensitization selectively in aged mice.
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Zhong Nan Da Xue Xue Bao Yi Xue Ban · Sep 2014
[Changes of Mu-opioid receptor and neuron-restrictive silencer factor in periaquductal gray in mouse models of remifentanil-induced postoperative hyperalgesia].
To determine the changes of Mu-opioid receptor (Mor) and neuron-restrictive silencer factor (NRSF) in periaquductal gray (PAG) in mouse models of remifentanil-induced postoperative hyperalgesia. ⋯ Intraoperative infusion of remifentanil induces postoperative hyperalgesia in mouse models, accompanied with decreased expressions of Mor and increased of NRSF level in PAG neurons, which may be involved in remifentanil induced hyperalgesia.
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Peripheral nerve injury increases the excitability of primary sensory neurons. This triggers the onset of neuropathic pain and maintains its persistence. Because changes in hyperpolarization-activated cyclic nucleotide-gated cation (HCN) channels are implicated in this process, we examined the action of the heart-rate-reducing agent, ivabradine, a clinically approved HCN blocker, in the rat chronic constriction injury (CCI) model of neuropathic pain. ⋯ Because ivabradine is effective at an oral dose that produces only moderate pharmacological heart rate reduction, and this is known to be well tolerated in a clinical context, these results underline its possible use in neuropathic pain management.