Articles: neuropathic-pain.
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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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The pathophysiology of neuropathic pain (NeP) in diabetic peripheral neuropathy (DPN) is unclear. A potential pathological feature associated with intraepidermal nerve fiber density (IENFD) loss in DPN is axonal swellings. ⋯ There was no clinical relationship to pain or clinical neuropathy severity for axonal swellings in DPN.
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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.