Articles: neuropathic-pain.
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Amygdala is involved in processing of primary emotions and particularly its central nucleus (CeA) also in pain control. Here we studied mechanisms mediating the descending control of mechanical hypersensitivity by the CeA in rats with a peripheral neuropathy in the left hind limb. For drug administrations, the animals had a guide cannula in the right CeA and an intrathecal catheter or another guide cannula in the medullary raphe. ⋯ The results indicate that depending on the dose, glutamate in the CeA has a descending facilitatory or inhibitory effect on neuropathic pain hypersensitivity. Serotoninergic raphe neurons are involved in mediating both of these effects. Spinally, the 5-HT3 receptor contributes to the increase and the 5-HT1A receptor to the decrease of neuropathic hypersensitivity induced by amygdaloid glutamate.
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Arch Phys Med Rehabil · Apr 2015
Review Meta AnalysisRepetitive transcranial magnetic stimulation in chronic pain: a review of the literature.
To review the literature on the analgesic effects of repetitive transcranial magnetic stimulation (rTMS) in chronic pain according to different pain syndromes and stimulation parameters. ⋯ rTMS has potential utility in the management of chronic pain; however, studies using maintenance sessions of rTMS and assessing the effects of rTMS on the different aspects of chronic pain are needed to provide a more solid basis for its clinical application for pain relief.
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Neurosci Biobehav Rev · Apr 2015
Review Comparative StudyComparison of operant escape and reflex tests of nociceptive sensitivity.
Testing of reflexes such as flexion/withdrawal or licking/guarding is well established as the standard for evaluating nociceptive sensitivity and its modulation in preclinical investigations of laboratory animals. Concerns about this approach have been dismissed for practical reasons - reflex testing requires no training of the animals; it is simple to instrument; and responses are characterized by observers as latencies or thresholds for evocation. ⋯ Numerous disparities between results for reflex and operant escape measures are described, but the results of operant testing are consistent with evidence from humans. Objective reasons are given for experimenters to choose between these and other methods of evaluating the nociceptive sensitivity of laboratory animals.
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Pain is a commonly reported symptom following surgery that is more likely to occur in individuals psychologically distressed prior to surgery. Monitoring processing style, a cognitive tendency to focus on health-related threats, has been associated with increased reporting of somatic symptoms, but no studies have specifically addressed the link between this cognitive style and pain. This prospective clinical study aimed to investigate whether monitoring processing style predicted post-surgical pain in women undergoing breast surgery, controlling for pre-surgical psychological distress. ⋯ Pre-surgical monitoring processing style was an independent predictor of post-surgical neuropathic pain, even when accounting for pre-surgical psychological distress. Since the reduction of post-surgical pain is a key goal of healthcare, efforts should be made prior to breast cancer surgery to counsel and support individuals with high monitoring processing styles irrespective of their level of distress.
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Neuropathic and inflammatory pain promote a large number of persisting adaptations at the cellular and molecular level, allowing even transient tissue or nerve damage to elicit changes in cells that contribute to the development of chronic pain and associated symptoms. There is evidence that injury-induced changes in chromatin structure drive stable changes in gene expression and neural function, which may cause several symptoms, including allodynia, hyperalgesia, anxiety, and depression. Recent findings on epigenetic changes in the spinal cord and brain during chronic pain may guide fundamental advances in new treatments. Here, we provide a brief overview of epigenetic regulation in the nervous system and then discuss the still-limited literature that directly implicates epigenetic modifications in chronic pain syndromes.