European journal of pain : EJP
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Although electroacupuncture is widely used in chronic pain management, it is quite controversial due to its unclear mechanism. We hypothesised that EA alleviates pain by inhibiting degradation of the ecto-nucleotidase prostatic acid phosphatase (PAP) and facilitating ATP dephosphorylation in dorsal root ganglions (DRGs). ⋯ In a mouse model of chronic pain, electroacupuncture treatment increased levels of prostatic acid phosphatase (PAP: an ecto-nucleotidase known to relieve pain hypersensitivity) by inhibiting PAP degradation in dorsal root ganglions. This promoted extracellular ATP dephosphorylation, inhibited glia activation and eventually alleviated peripheral nerve injury-induced mechanical pain hypersensitivity in mice. Our findings represent an important step forward in clarifying the mechanisms of pain relief afforded by acupuncture treatment.
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Electrical stimulation of skin afferents can induce somatosensory plasticity in humans. Nevertheless, it is unknown if this is possible to do through percutaneous stimulation of a peripheral nerve, which will allow for regional anaesthesia interventions. Furthermore, potentiation protocols applied over mainly non-nociceptive fibres inhibit nociception in rodents, but this has not been tested in humans. ⋯ This works provides evidence that is possible to induce antinociceptive plasticity in a wide territory using pPNS. Moreover, it demonstrates for the first time in humans that a protocol aiming to produce long-term potentiation applied predominantly over non-nociceptive afferents induces hypoesthesia and hypoalgesia.
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It has been suggested that chronotype, the individual preference for 24-h circadian rhythms, influences health. Sleep problems and mental distress are amongst the greatest risk factors for musculoskeletal (MS) pain. The aims of this study were first, to explore the associations between chronotypes and MS pain, with special reference to disabling MS pain and second, to test whether mental distress and insomnia have a modifying role in the associations between chronotypes and MS pain. ⋯ This study shows that evening and intermediate chronotypes are associated with disabling MS pain, but that mental distress, insomnia and coexisting diseases also play a role in these associations.
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Estimating others' pain is a challenging inferential process, associated with a high degree of uncertainty. While much is known about uncertainty's effect on self-regarding actions, its impact on other-regarding decisions for pain have yet to be characterized. ⋯ Uncertainty biases decision-making but it is unclear if it affects choice behavior on pain for others. In examining this question, we found individuals were generally risk-seeking when faced with looming pain, but more so for self; and assigned higher monetary values and subjective ratings on another's pain. However, uncertainty dampened agents' assessment of a stranger's pain, suggesting latent variables may contradict overt altruism. This bias may underlie pain underestimation in clinical settings.