Articles: hyperalgesia.
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Arthritis and rheumatism · May 2010
Spinal tumor necrosis factor alpha neutralization reduces peripheral inflammation and hyperalgesia and suppresses autonomic responses in experimental arthritis: a role for spinal tumor necrosis factor alpha during induction and maintenance of peripheral inflammation.
In addition to the sensitization of pain fibers in inflamed tissues, the increased excitability of the spinal cord is an important mechanism of inflammatory pain. Furthermore, spinal neuronal excitability has been suggested to play a role in modulating peripheral inflammation. This study was undertaken to test the hypothesis that spinal actions of the proinflammatory cytokine tumor necrosis factor alpha (TNFalpha) add significantly to both hyperalgesia and maintenance of peripheral inflammation. ⋯ Our findings indicate that spinal TNFalpha plays an important role in both pain signaling and modulation of peripheral inflammation. Thus, neutralizing this cytokine at the spinal site not only represents a putative therapeutic option for different pain syndromes, but may be directly used to attenuate peripheral inflammation.
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The role of ion channels expressed in sensory neurons on mechanical and thermal hyperalgesia was examined in a rat model of cisplatin-induced peripheral neuropathy. The rats were injected with 3mg/kg of cisplatin intraperitoneally once per week for five consecutive weeks. The von Frey test, pin-prick test and plantar test were performed to examine any noxious sensitivity of the skin. ⋯ Antagonists against P2X(3,2/3) and ASICs showed a suppressive effect on both skin and muscle hyperalgesia induced by cisplatin administration. Upregulation of TRPV2, P2X(3), and ASIC3 may play important roles in the mechanical hyperalgesia induced by cisplatin. Furthermore, cisplatin treatment also induced muscle hyperalgesia in muscle afferent neurons in connection with the upregulation of P2X(3) and ASIC3.
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Topical application of capsaicin commonly produces burning, stinging and itching as well as hyperalgesia to heat stimuli via activation of transient receptor potential vanilloid subtype 1. ⋯ Our observations indicate that African Americans display a limited hypersensitivity following topical capsaicin, compared with the three other ethnic groups.
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Journal of neurotrauma · May 2010
Sensory stimulation prior to spinal cord injury induces post-injury dysesthesia in mice.
Chronic pain and dysesthesias are debilitating conditions that can arise following spinal cord injury (SCI). Research studies frequently employ rodent models of SCI to better understand the underlying mechanisms and develop better treatments for these phenomena. While evoked withdrawal tests can assess hypersensitivity in these SCI models, there is little consensus over how to evaluate spontaneous sensory abnormalities that are seen in clinical SCI subjects. ⋯ Mice subjected to either stimulus paradigm showed increased OG compared with unstimulated or uninjured mice. Histological analysis showed no difference in spinal cord lesion size due to sensory stimulation, or between mice that overgroomed or did not overgroom. The relationship between prior stimulation and contusion injury in mice that display OG indicates a critical interaction that may underlie one facet of spontaneous neuropathic symptoms after SCI.
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Present literature and clinical practice provide strong support for the use of aerobic exercise in reducing pain and improving function for individuals with chronic musculoskeletal pain syndromes. However, the molecular basis for the positive actions of exercise remains poorly understood. Recent studies suggest that neurotrophin-3 (NT-3) may act in an analgesic fashion in various pain states. ⋯ This is the first study demonstrating the effect of exercise on deep tissue mechanical hyperalgesia in a rodent model of pain and providing a possible molecular basis for exercise training in reducing muscular pain.