European journal of pain : EJP
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The different phenotypic presentations of fibromyalgia (FM) have been infrequently studied and may have diagnostic and therapeutic implications. The aim of this study was to explore differences between FM patients with classical symmetric (s-FM) presentation and FM patients with marked asymmetric (a-FM) pain. ⋯ Current fibromyalgia criteria may contain different phenotypes of fibromyalgia based on the lateralization of pain.
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Unilateral injection of Complete Freund's Adjuvant (CFA) into the intra-plantar surface of the rodent hindpaw elicits chronic inflammation and hyperalgesia in the ipsilateral hindlimb. Mechanisms contributing to this hyperalgesia may act over multiple time courses and can include changes in ion channel expression and post-translational SUMOylation. Hyperpolarization-activated, cyclic nucleotide-gated (HCN) channels mediate the hyperpolarization-activated current, Ih . An HCN2-mediated increase in C-nociceptor Ih contributes to mechanical hyperalgesia in the CFA model of inflammatory pain. Changes in HCN2 post-translational SUMOylation and protein expression have not been systematically documented for a given dorsal root ganglia (DRG) throughout the time course of inflammation. ⋯ Nociceptor HCN2 channels mediate an increase in Ih that is necessary for mechanical hyperalgesia in a CFA model of chronic pain, but the mechanisms producing the increase in nociceptor Ih have not been resolved. The data presented here suggest that the increase in Ih during the early stages of inflammation may be mediated by an increase in HCN2 protein expression and post-translational SUMOylation.
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At least one-third of HIV-1-afflicted individuals experience peripheral neuropathy. Although the underlying mechanisms are not known, they may involve neurotoxic HIV-1 proteins. ⋯ The ability of Tat to decrease oedema, paw swelling, and limit allodynia suggests a sequel of events in which Tat-induced functional deficits precede the onset of mechanical hypersensitivity. Moreover, HIV-1 Tat attenuated responses to inflammatory and neuropathic insults in a sex-dependent manner. HIV-1 Tat appears to directly contribute to HIV sensory neuropathy and reveals sex differences in HIV responsiveness and/or the underlying peripheral neuroinflammatory and nociceptive mechanisms.
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Fibromyalgia has been associated with various physical and mental disorders. However, these comorbidities need to be quantified in a population-based study. ⋯ We showed here a strong association of self-reported fibromyalgia with both mental and physical comorbidities. We showed that among participants with self-reported fibromyalgia, more than 8 out of 10 had at least three other physical comorbidities, and almost half had at least three mental comorbidities. This is a cross-sectional study using a representative sample of the US population with highly reliable psychiatric diagnosis that makes our results generalizable. Practitioners managing fibromyalgia should search and treat these comorbidities.
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Fibromyalgia (FM) is a syndrome characterized by altered pain processing at central and peripheral level, whose pathophysiologic mechanisms remain obscure. We aimed at exploring the structural changes of peripheral nociceptor measured by skin biopsy, the functional changes of central nociceptive pathway assessed by laser-evoked potentials (LEP), and their correlation with clinical features and comorbidities. ⋯ Central impairment of pain processing likely underlies FM, which in most patients is associated with mild proximal small fibre pathology.