Articles: hyperalgesia.
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Pharmacol. Biochem. Behav. · Jan 2009
Increased hyperalgesia by 5-nitro-2, 3-(phenylpropylamino)-benzoic acid (NPPB), a chloride channel blocker in crush injury-induced neuropathic pain in rats.
Chloride channels belong to diverse group of anion selective channels involved in different signaling processes. The present study was planned to investigate the involvement of chloride channels in crush injury-induced neuropathic pain in rats by using ivermectin, a ligand gated chloride channel opener and NPPB, a CaCC blocker. The effect of ivermectin (5, 10, 20 mg/kg i.p. or 50, 100 and 200 microg/rat by i.c.v. route) and NPPB (10, 20 and 40 mg/kg i.p.) was investigated on pain behavioural thresholds in crush injury-induced neuropathic pain rat model. ⋯ NPPB (20 and 40 mg/kg i.p.) significantly reduced the pain threshold crush injury neuropathic pain model suggesting its hyperalgesic effect. The results showed that NPPB increased significantly the mechanical and thermal hyperalgesia in crush injury-induced neuropathic pain rat model, whereas ivermectin, either by i.p. or i.c.v. route of administration, has no effect on pain symptoms in this model. NPPB hyperalgesic effect is independent of CaCCs inhibition and may be due to blockade of Ca2+-activated K+ channel.
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British medical bulletin · Jan 2009
ReviewVisceral pain hypersensitivity in functional gastrointestinal disorders.
Functional gastrointestinal disorders (FGIDs) are a highly prevalent group of heterogeneous disorders whose diagnostic criteria are symptom based in the absence of a demonstrable structural or biochemical abnormality. Chronic abdominal pain or discomfort is a defining characteristic of these disorders and a proportion of patients may display heightened pain sensitivity to experimental visceral stimulation, termed visceral pain hypersensitivity (VPH). ⋯ Tangible progress will only be made in the treatment of VPH when we begin to individually characterize patients with FGIDs based on their clinical phenotype, genetics and visceral nociceptive physiology.
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To compare cutaneous sensory thresholds, habituation to somatic stimuli, and tendency towards catastrophic reaction to painful stimuli in patients with Painful Bladder Syndrome (PBS) to controls without PBS. ⋯ Our data suggests that habituation to stimuli may be impaired and that a catastrophic reaction to perceived stimuli may be involved in the sensory experience of PBS patients and facilitate chronic pain. Neurourol. Urodyn. 28:400-404, 2009. (c) 2009 Wiley-Liss, Inc.
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In addition to caudal subnucleus caudalis (Vc) of the spinal trigeminal complex, recent studies indicate that the subnuclei interpolaris/caudalis (Vi/Vc) transition zone plays a unique role in processing deep orofacial nociceptive input. Studies also suggest that glia and inflammatory cytokines contribute to the development of persistent pain. By systematically comparing the effects of microinjection of the antiinflammatory cytokine interleukin (IL)-10 and two glial inhibitors, fluorocitrate and minocycline, we tested the hypothesis that there was a differential involvement of Vi/Vc and caudal Vc structures in deep and cutaneous orofacial pain. ⋯ These results support the hypothesis that the Vi/Vc transition zone is involved in deep orofacial injury and suggest that glial inhibition and interruption of the cytokine cascade after inflammation may provide pain relief.