Articles: hyperalgesia.
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Comparative Study
Mechanical allodynia but not thermal hyperalgesia is impaired in mice deficient for ERK2 in the central nervous system.
Extracellular signal-regulated kinase (ERK) plays critical roles in pain plasticity. However, the specific contribution of ERK2 isoforms to pain plasticity is not necessarily elucidated. Here we investigate the function of ERK2 in mouse pain models. ⋯ In Erk2 CKO mice, compensatory hyperphosphorylation of ERK1 was detected in the spinal cord. However, ERK1 did not appear to influence nociceptive processing because the additional inhibition of ERK1 phosphorylation using MEK (MAPK/ERK kinase) inhibitor SL327 did not produce additional changes in formalin-induced spontaneous behaviors in Erk2 CKO mice. Together, these results indicate that ERK2 plays a predominant and/or specific role in pain plasticity, while the contribution of ERK1 is limited.
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Anesthesia and analgesia · Nov 2012
Ginkgo biloba extract attenuates hyperalgesia in a rat model of vincristine-induced peripheral neuropathy.
Chemotherapy-induced peripheral neuropathy is a common, dose-limiting side effect of cancer chemotherapeutic drugs. Hyperalgesia is a common component of neuropathic pain. Ginkgo biloba extract (GBE) is an oriental herbal medicine that has various pharmacological actions. In this study, we evaluated the effects of oral GBE on hyperalgesia in a rat model of vincristine-induced neuropathy. ⋯ This study demonstrates that oral administration of GBE is associated with a dose-dependent antihyperalgesic effect on mechanical and cold stimuli in a rat model of vincristine-induced neuropathy.
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Comparative Study
Childhood diabetic neuropathy: functional impairment and non-invasive screening assessment.
Sensory diabetic neuropathy, determined by nerve conduction studies, is common in children with Type 1 diabetes. Diabetic neuropathy diagnoses are rarely made in paediatric daily care because they are asymptomatic, vibration detection is mostly normal and nerve-conduction testing is impractical. The present study aims to: (1) describe somatosensory dysfunction in children with diabetes, (2) test whether diabetes duration and HbA(1c) are related to somatosensory dysfunction and (3) identify the best screening test for large-fibre dysfunction, as indicated by nerve conduction studies. ⋯ Almost half of the children with diabetes have subclinical large- and small-fibre neuropathies. Tactile detection was better than vibration for neuropathy assessment. Quantitative sensory testing is a valuable tool for assessment of neuropathy as well as a target of interventional studies in children with diabetes.
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Among receptors mediating serotonin actions in pain control, the 5-HT(7)R is of special interest because it is expressed by primary afferent fibers and intrinsic GABAergic and opioidergic interneurons within the spinal dorsal horn. Herein, we investigated whether GABA and/or opioids contribute to 5-HT(7)R-mediated control of neuropathic pain caused by nerve ligation. Acute administration of 5-HT(7)R agonists (AS-19, MSD-5a, E-55888) was found to markedly reduce mechanical and thermal hyperalgesia in rats with unilateral constriction injury to the sciatic nerve (CCI-SN). ⋯ When injected intrathecally (i.t.), bicuculline (3 μg i.t.), but neither phaclofen (5 μg i.t.) nor naloxone (10 μg i.t.), significantly reduced the anti-hyperalgesic effects of 5-HT(7)R activation (E-55888, 10 mg/kg s.c.) in CCI-SN rats. These data support the idea that 5-HT(7)R-mediated inhibitory control of neuropathic pain is underlain by excitation of GABAergic interneurons within the dorsal horn. In addition, 5-HT(7)R activation-induced c-Fos increase in the nucleus tractus solitarius and the parabrachial area suggests that supraspinal mechanisms might also be involved.
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Hyperalgesia has been observed in active opioid addicts (OAs). The aim of this study was to explore whether opioid-induced hyperalgesia (OIH) is a reversible phenomenon. ⋯ It is suggested that altered pain perception in OAs is a reversible phenomenon that may require a long period of abstinence to reset, rather than being an individual long-term stable trait.