Pain
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The primary purpose of this study was to investigate the influence of an individual's Gender Role Expectations of Pain (GREP) on experimental pain report. One hundred and forty-eight subjects (87 females and 61 males) subjects underwent thermal testing and were asked to report pain threshold, pain tolerance, VAS ratings of pain intensity and unpleasantness, and a computerized visual analogue scales (VAS) rating of pain intensity during the procedure. Subjects completed the GREP questionnaire to assess sex-related stereotypic attributions of pain sensitivity, pain endurance, and willingness to report pain. ⋯ Results provide support for two competing but not mutually exclusive hypotheses related to the sex differences in experimental pain. Both psychosocial factors and first-order, biological sex differences remain as viable explanations for differences in experimental pain report between the sexes. It appears that GREP do play a part in determining an individual's pain report and may be contributing to the sex differences in the laboratory setting.
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Case Reports
Case reports - reversal of sensory deficit associated with pain relief after treatment with gabapentin.
Many patients with neuropathic pain have coexistent sensory deficits. Neuropathic pain may be alleviated by a variety of drugs but sensory deficits are assumed to be permanent. ⋯ The cases are presented and possible explanations for the observed sensory improvements are discussed. These findings raised exciting neurophysiological questions in addition to being of potential importance to the clinical problem of neurotrophic tissue injury.
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Inflammation induces an up-regulation of neuropeptide tyrosine (NPY) and its receptors in the dorsal horn, suggesting an important role in nociceptive transmission. Our initial studies revealed that NPY dose-dependently increased hotplate response latency, and to a lesser degree, thermal paw withdrawal latency (PWL); these effects occurred at doses that affect neither motor coordination (as assessed by the rotarod test) nor paw skin temperature. We next evaluated the behavioral effects of intrathecal administration of NPY and NPY antagonists with the aim of assessing the contribution of NPY to correlates of persistent nociception associated with the unilateral plantar injection of carrageenan or complete Freund's adjuvant (CFA). ⋯ When administered alone, BIBO 3304 (but not BIIE 0246) slightly decreased thermal PWL on the side ipsilateral (25% change), but not contralateral, to CFA injection; this suggests that inflammation strengthens inhibitory NPY tone. We conclude that spinal Y1 receptors contribute to the inhibitory effects of NPY on thermal hypersensitivity in the awake rat. Further studies are necessary to determine whether enhanced release of NPY and Y1-mediated inhibition of spinal nociceptive transmission ultimately results in a compensatory, adaptive inhibition of thermal hypersensitivity in the setting of inflammation.
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Cross-sectional studies have consistently shown a relationship between chronic widespread pain, the clinical hallmark of fibromyalgia, and psychological distress. These studies cannot distinguish the direction of any causal relationship. Recent population based studies have reported that such pain is predictive of future distress. ⋯ Chronic widespread pain was associated with increased levels of psychological distress at follow up. However, a more rigorous analysis indicated that the association between baseline pain status with future distress was explained by concomitant features of chronic pain rather than pain per se. These findings indicate that it is those persons with chronic widespread pain in the presence of other physical and psychosocial factors who will become distressed.