European journal of pain : EJP
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Mechanical hyperalgesia may develop following tissue inflammation or nerve injury. Basically, peripheral sensitization leads to primary hyperalgesia at the site of injury, whereas secondary hyperalgesia occurs in the surrounding tissue and results from central sensitization. The present study focuses on the cerebral processing of secondary mechanical hyperalgesia. ⋯ In contrast to PPC, we found a significant correlation between increases of magnetic field strengths within bilateral S2 with the increase of pain ratings during pin-prick hyperalgesia. We conclude that the S2 cortex may be involved for the processing of secondary mechanical hyperalgesia in the human brain. PPC activation may reflect higher attentional processing during mechanical hyperalgesia.
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The analgesic effect of nitrous oxide (N(2)O) is thought to depend on noradrenaline release in the spinal cord following activation of descending inhibitory neurons. In addition to this indirect facilitation of inhibition in the spinal cord, we previously showed direct inhibition of glutamate receptors in dorsal horn neurons by N(2)O. Since general anesthetics could possibly affect excitatory and/or inhibitory components of synaptic transmission, we sought to evaluate the direct effect of N(2)O on inhibitory transmission in spinal cord neurons. ⋯ N(2)O did not affect the amplitude, frequency or decay time probability distribution of either GABA or glycine receptor-mediated miniature postsynaptic currents. We further sought to determine the effect of N(2)O on focal stimulation-evoked synaptic currents mediated by GABA and glycine receptors, and found no effect in the majority of neurons. These and other findings suggest that N(2)O has a discrete action in the spinal cord, distinct from the effects of the volatile anesthetics, consisting of inhibition of excitation in SG neurons through an action on ionotropic glutamatergic receptors and potentiation of inhibition through the descending noradrenergic system.
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Peripheral injuries can lead to sensitization of neurons in dorsal root ganglia (DRGs), which can contribute to chronic pain. The neurons are sensitized by a combination of physiological and biochemical changes, whose full details are still obscure. Another cellular element in DRGs are satellite glial cells (SGCs), which surround the neurons, but little is known about their role in nociception. ⋯ Gap junction blockers abolished the inflammation-induced changes in SGCs and neurons, and significantly reversed the pain behavior. We propose that inflammation induces augmented cell coupling in DRGs that contributes to neuronal hyperexcitability, which in turn leads to visceral pain. Gap junction blockers may have potential as analgesic drugs.
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We compared the methodology and the recommendations of evidence-based guidelines for the management of fibromyalgia syndrome (FMS) to give an orientation within the continuously growing number of reviews on the therapy of FMS. Systematic searches up to April 2008 of the US-American National Guideline Clearing House, the Scottish Intercollegiate Guidelines Network, the Association of the Scientific Medical Societies in Germany (AWMF) and Medline were conducted. Three evidence-based guidelines for the management of FMS published by professional organizations were identified: The American Pain Society (APS) (2005), the European League Against Rheumatism (EULAR) (2007), and the AWMF (2008). ⋯ In contrast, EULAR assigned the highest level of recommendation to a set of to pharmacological treatment. Although there was some consistency in the recommendations regarding pharmacological treatments among the three guidelines, the APS and AWMF guidelines assigned higher ratings to CBT and multicomponent treatments. The inconsistencies across guidelines are likely attributable to the criteria used for study inclusion, weighting systems, and composition of the panels.
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Comparative Study
Effectiveness of a multimodal inpatient treatment for pediatric chronic pain: a comparison between children and adolescents.
To evaluate short and long-term treatment outcome of children (7-10 years) in comparison to adolescents (11-18 years) with disabling chronic pain following multimodal inpatient pain treatment. ⋯ Children display similar pain-characteristics to adolescents when entering inpatient treatment. A multimodal inpatient program appears to stop the the long-term vicious cycle of disability and pain for both children and adolescents. The demonstrated gender differences raise issues for further research and the possibility of additional pain management strategies for girls.