European journal of pain : EJP
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The purpose of the study was to examine the trends in opioid consumption in the five Nordic countries between 2002 and 2006 and to explore possible explanations for changes in the quality and quantity of opioids consumed. ⋯ Consumption of opioid analgesics in the Nordic countries showed changes over the five year period that cannot be explained by pharmacology, price, reimbursement or prescription regulations. Marketing has most likely significantly influenced the type and amount of opioids consumed.
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Nitric oxide, which has been implicated in the development of hyperalgesia in the spinal system, has not been systematically studied in the trigeminal system, especially in the context of inflammatory muscle pain condition. In this study, we investigated the functional role of centrally released nitric oxide in the pathogenesis of orofacial muscle pain. Specifically, we examined the contribution of neuronal, inducible and endothelial nitric oxide synthases, nNOS, iNOS and eNOS, respectively, in mediating masseter hypersensitivity under acute inflammatory condition. ⋯ The expression of all three nitric oxide synthases was significantly up-regulated 30-60 min following capsaicin stimulation, which paralleled the time course of the development of capsaicin-induced masseter hypersensitivity. Pretreatment with each NOS inhibitor significantly attenuated the masseter hypersensitivity. These data showed that all three NOS in the Vc are functionally important for the development of craniofacial muscle hyperalgesia and suggest that the three NOS are closely orchestrated to regulate the level of nitric oxide under normal and pathologic conditions.