European journal of pain : EJP
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Central neuropathic pain (CNP) is an excruciating condition, prevalent in up to a third of patients with multiple sclerosis (MS). Identifying CNP among MS patients is particularly challenging considering the ample comorbid chronic pain conditions and sensory disturbances entailed by the disease. The aim was to identify sensory features unique to CNP beyond those of chronic pain and MS. ⋯ Cluster analysis among patients with multiple sclerosis (MS) revealed that while central neuropathic pain is associated with thermal and mechanical hypoesthesia, musculoskeletal pain is involved with reduced pain inhibition and hyperalgesia; sensory profiles that provide insights into the mechanisms of these conditions and may promote an individually based pain management.
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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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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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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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Background Adaptation to a constant sensory stimulus involves many sites along the path of sensory volleys towards perception. The evaluation of such phenomenon may be of clinical interest. We studied adaptation to a constant temperature stimulus in healthy subjects to set normative data and in patients with sensory polyneuropathy (SPN), as proof of concept. ⋯ Patients showed delayed time to respond, decreased maximal sensation and reduced adaptation with respect to healthy subjects. Differences were more pronounced at low and intermediate temperatures (39ºC to 43ºC). The method is of easy implementation and shows clinically relevant abnormalities in patients with sensory polyneuropathy.