Articles: hyperalgesia.
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Identification of mechanisms for pain/hyperalgesia following spinal cord injury requires long-term evaluation of individual subjects because of the variability in effect over time for humans. ⋯ Histology revealed that hyperalgesia occurred when there was: (1) damage to spinal white matter; or (2) cystic cavitation; or (3) compression and distortion of the spinal cord without an obvious loss of grey or white matter.
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Observational Study
The effects of electroacupuncture on analgesia and peripheral sensory thresholds in patients with burn scar pain.
The aim of this study is to observe if the effects of electro-acupuncture (EA) on analgesia and peripheral sensory thresholds are transposable from the model of heat pain in volunteers to the clinical setting of burn scar pain. After severe burns, pathological burn scars (PPBS) may occur with excruciating pain that respond poorly to treatment and prevent patients from wearing their pressure garments, thereby leading to unesthetic and function-limiting scars. EA might be of greater benefit in terms of analgesia and functional recovery, should it interrupt this vicious circle by counteracting the peripheral hyperalgesia characterizing PPBS. ⋯ The fact that acupuncture did not correct the pain nor the nociceptive thresholds in this subgroup requires further investigation. We also observed a statistically and clinically relevant reduction in VAS for pruritus for all patients - even those from the subgroup of non-responders to pain - that is worth to be mentioned and requires further studies to be confirmed. This observational study is the first that confirms the effects of acupuncture on analgesia and nociceptive thresholds in the clinical setting of burn pain only for patients presenting with a burn-localized but not a generalized hyperalgesia.
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Pulsed radiofrequency (PRF) treatment is a minimally invasive technique with multiple therapeutic applications. Hyperpolarization-activated cyclic nucleotide-gated (HCN) channel mediating Ih may regulate neuropathic pain signaling. This study aimed to determine whether PRF suppresses neuropathic pain by altering HCN channel expression in dorsal root ganglion (DRG) neurons. ⋯ The results showed that thermal hyperalgesia, mechano-allodynia, and mechano-hyperalgesia were lower, and DRG expression levels of HCN1 and HCN2 higher, in the PRF group compared with sham control animals (all P < 0.05 at D14). In conclusion, PRF can upregulate HCN channel expression in the DRG of rats with sciatic nerve CCI. How this regulation of Ih in nociceptive afferents contributes to the suppression of neuropathic pain by PRF remains to be determined.
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Int. Immunopharmacol. · Sep 2015
Inflammatory mediators involved in the paw edema and hyperalgesia induced by Batroxase, a metalloproteinase isolated from Bothrops atrox snake venom.
Snake venom metalloproteinases have been described as responsible for several inflammatory effects. In this study, we investigated the edema and hyperalgesia induced in rats by Batroxase, a P-I metalloproteinase from Bothrops atrox venom, along with possible inflammatory mediators involved in these responses. Batroxase or sterile saline was injected into rat paws and the edema and hyperalgesic effects were evaluated for 6h by using a plethysmometer and a Von Frey system, respectively. ⋯ However, Batroxase itself induced minor degranulation of RBL-2H3 mast cells in vitro. Additionally, the inflammatory responses did not seem to be related to prostaglandins, bradykinin or nitric oxide. Our results indicate a major involvement of histamine and leukotrienes in the edema and hyperalgesia induced by Batroxase, which could be related, at least in part, to mast cell degranulation.
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Archives of oral biology · Sep 2015
Synovial TRPV1 is upregulated by 17-β-estradiol and involved in allodynia of inflamed temporomandibular joints in female rats.
Women with reproductive capability are more likely to suffer from temporomandibular disorders (TMD), with orofacial pain as the most common complaint. In the past, we focused on the role of estradiol in TMD pain through the nervous system. In this study, we explored estradiol's influence on synoviocyte gene expressions involved in the allodynia of the inflamed TMJ. ⋯ Moreover, intra-TMJ injection of TRPV1 antagonist, capsazepine, significantly attenuated allodynia of the inflamed TMJ induced by intra-TMJ injection of CFA in female rats. This article presents a possible local mechanism for estradiol that may be involved in TMJ inflammation or pain in the synovial membrane through the pain-related gene TRPV1. This finding could potentially help clinicians understand the sexual dimorphism of TMD pain.