Articles: hyperalgesia.
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Anesthesia and analgesia · Nov 2010
Randomized Controlled TrialThe analgesic and antihyperalgesic effects of transcranial electrostimulation with combined direct and alternating current in healthy volunteers.
Transcranial electrostimulation (TES) has been reported to produce clinically significant analgesia, but randomized and double-blind studies are lacking. We investigated the analgesic and antihyperalgesic effects of TES in validated human experimental pain models. ⋯ TES produces significant, frequency-dependent antihyperalgesic and analgesic effects in humans. The characteristics of the TES effects indicate a high likelihood of its ability to modulate both peripheral sensitization of nociceptors and central hyperexcitability.
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Mixed evidence exists regarding whether irritable bowel syndrome (IBS) patients show increased somatic pain perception compared with controls. The current study used a deep, tonic somatic pain stimulus (ischemic pain) to evaluate somatic hypersensitivity in IBS patients. ⋯ The results of this study suggest that a widespread alteration in central pain processing in IBS patients may be present as they display hypersensitivity to ischemic arm pain, and ischemic pain threshold was associated with clinical symptoms. These findings could reflect a dysfunction in inhibitory pain systems in IBS patients, as ischemic (deep) pain may be under tonic inhibitory control.
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To describe the presence of widespread pressure pain hyperalgesia and myofascial trigger points (TrPs) in neck and shoulder muscles in patients with postmastectomy pain. ⋯ Our findings revealed bilateral widespread pressure pain hypersensitivity in patients with postmastectomy pain. In addition, the local and referred pain elicited by active TrPs reproduced neck and shoulder/axillary complaints in these patients. These results suggest peripheral and central sensitization in patients with postmastectomy pain.
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Interleukin-6 (IL-6) is an inflammatory cytokine known to modulate muscle pain. However, the mechanisms underlying this effect still remain unclear. Here we show that the injection of IL-6 into mice gastrocnemius muscle evoked a time- and dose-dependent mechanical hyperalgesia. ⋯ Simultaneous flow cytometry measurements revealed that ERK, p38 MAPK and JNK were phosphorylated as early as 5 min after IL-6 injection. These findings provided new evidence indicating that IL-6 exerts a relevant role in the development and maintenance of muscular hyperalgesia. The IL-6-mediated muscular pain response involves resident cell activation, polymorphonuclear cell infiltration, cytokine production, prostanoids and sympathomimetic amines release and the activation of intracellular pathways, especially MAPKs.
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Painful neuropathy is a common complication of diabetes. Particularly in the early stage of diabetic neuropathy, patients are characterized by burning feet, hyperalgesia to heat, and mechanical stimuli, as if residual nociceptors were sensitized. Such symptoms are barely explained by common pathophysiological concepts of diabetic neuropathy. ⋯ Diabetic C-fibers show exaggerated sensitivity to hyperglycemic hypoxia with and without additional acidosis, conditions that are thought to mimic ischemic episodes in diabetic nerves. Ongoing C-fiber discharge is known to induce spinal sensitization. Together with altered receptor and ion channel expressions this may contribute to painful episodes in diabetic neuropathy.