European journal of pain : EJP
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Attentional biases for pain-related information have been commonly reported in patients with chronic pain. Biases may also exist in individuals who recently experienced an episode of acute clinical pain, although limited investigation has been conducted. The present study is the first to explore attentional biases in women who experienced recent menstrual pain. ⋯ Pain-related attentional biases are associated with recent menstrual pain severity. The experience and severity of pain, rather than its duration (i.e., whether pain is chronic or acute), may be the primary determinants of pain-related attentional bias. Future research could explore attentional biases in acute clinical pain samples to confirm this notion.
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Nerve growth factor (NGF) causes early heat and delayed mechanical hyperalgesia. Axonal transport might contribute to lasting responses. Temporal hyperalgesia development was investigated by administering NGF in paraspinal skin. Transient receptor potential ankyrin 1 (TRPA1) is up-regulated by NGF and chemical responsiveness to cinnamon aldehyde (TRPA1 agonist) was quantified. ⋯ NGF causes immediate heat hyperalgesia probably linked to an up-regulation and sensitization of transient receptor potential vanilloid 1 and possibly other proteins involved in heat transduction. The delayed mechanical hyperalgesia is apparently independent of the time required for axonal transport of NGF receptor complexes. Local mRNA translation at axonal terminals and protein accumulation is hypothesized being involved in sustained NGF-evoked hyperalgesia.
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Stress is known to promote several forms of muscle pain including non-specific low back pain. However, the question if stress alone activates nociceptive central neurons has not been studied systematically. Here, we investigated the influence of repeated immobilization stress on dorsal horn neurons and behaviour in the rat. ⋯ This study shows that stress alone is sufficient to sensitize dorsal horn neurons. The data may explain the enhanced pain low back patients report when they are under stress. The increased resting discharge may lead to spontaneous pain.
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Anxiety, in particular pain-related anxiety, plays an important role in explaining the severity of pain complaints and pain-related disability in both adults and children with chronic pain. The fear-avoidance model (FAM) describes how pain-related anxiety plays a critical role in the maintenance of pain-avoidance behaviour, which in turn influences pain-related disability. However, the FAM does not take into account broader aspects of adolescence, such as social functioning, which could be negatively impacted by anxiety. In addition, most studies examining the role of anxiety in pain have used small convenience or clinical samples. By using a large UK epidemiological database, this study investigated the associations between pain-related anxiety, disability and judgements of social impairment. ⋯ Pain-related anxiety was associated with greater pain-related disability and impaired social functioning. Social functioning should be explored as an integral part of fear-avoidance models of adolescent chronic pain.
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Protocols for testing conditioned pain modulation (CPM) vary between different labs/clinics. In order to promote research and clinical application of this tool, we summarize the recommendations of interested researchers consensus meeting regarding the practice of CPM and report of its results.