Articles: hyperalgesia.
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Topical high-dose capsaicin acting on TRPV1 receptors and inducing an intraepidermal decrease in the small nerve fibre count is effective in treating neuropathic pain (NP). Sensory changes after capsaicin application, their correlation with pain relief and their role as possible predictors of response have been insufficiently analysed. We hypothesized a positive correlation between pain relief and increase in the warmth detection threshold (WDT), indicating loss of C-fibre function, and higher response rates in patients with preserved C-fibre function or heat hyperalgesia before application. ⋯ Efficacy of capsaicin does not correlate with the induced loss of function of small fibres, measured by QST. Presence of cold and pinprick hyperalgesia seems to be predictive of response to capsaicin (8%).
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J Oral Facial Pain Headache · Jan 2016
Comparative StudyUpregulation of the Purinergic Receptor Subtype P2X3 in the Trigeminal Ganglion Is Involved in Orofacial Pain Induced by Occlusal Interference in Rats.
To evaluate whether the purinergic receptor subtype P2X3 (P2X3R) in trigeminal ganglion (TG) neurons is involved in hyperalgesia of the temporomandibular joints (TMJs) and masseter muscles associated with placement of an occlusal interference. ⋯ Upregulated P2X3R expression in the TG may contribute to orofacial pain development induced by an occlusal interference. P2X3R may be a therapeutic target for chronic TMJ or masseter muscle pain.
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Pain-sensing sensory neurons (nociceptors) of the dorsal root ganglia (DRG) and dorsal horn (DH) can become sensitized (hyperexcitable) in response to pathological conditions such as diabetes, which in turn may lead to the development of painful peripheral diabetic neuropathy (PDN). Because of incomplete knowledge about the mechanisms underlying painful PDN, current treatment for painful PDN has been limited to somewhat nonspecific systemic drugs that have significant side effects or potential for abuse. ⋯ Understanding details of posttranslational regulation of nociceptive channel activity may facilitate development of novel therapies for treatment of painful PDN. We argue that pharmacological targeting of the specific pathogenic mechanism rather than of the channel per se may cause fewer side effects and reduce the potential for drug abuse in patients with diabetes.
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10 Hz conditioning electrical stimulation (CES) has been shown to induce long-term potentiation (LTP)-like pain amplification similar to traditional 100 Hz CES in healthy humans. The aim of this study was to assess the test-retest reliability and to estimate sample sizes required for future crossover and parallel study designs. ⋯ The reliability of 10 Hz CES was acceptable in inducing LTP-like effects in the assessments of superficial blood flow, heterotopic mechanical hyperalgesia, and dysesthesia in terms of sample sizes for future crossover study designs.
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The primary complaint of burn victims is an intense, often devastating spontaneous pain, with persistence of mechanical and thermal allodynia. The transient receptor potential channels, TRPV1 and TRPA1, are expressed by a subset of nociceptive sensory neurons and contribute to inflammatory hypersensitivity. Although their function in the periphery is well known, a role for these TRP channels in central pain mechanisms is less well defined. ⋯ Finally, i.t. injection of ketoconazole significantly reversed post-burn mechanical and thermal allodynia. Our data indicate that spinal cord TRPV1 and TRPA1 contributes to pain after burn and identifies a novel class of oxidized lipids elevated in the spinal cord after burn injury. Since the management of burn pain is problematic, these findings point to a novel approach for treating post-burn pain.