Pain
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The Self-Administered Leeds Assessment of Neuropathic Symptoms and Signs (S-LANSS), an assessment tool to determine if pain is predominantly neuropathic, has not been validated in a community setting. Previously identified residents of Olmsted County, Minnesota, with chronic pain were recruited using a stratified randomization process to increase the frequency of neuropathic pain in the study sample. Subjects completed the S-LANSS in mailed and telephone formats, and underwent clinical assessment to determine if a component of their pain was neuropathic. ⋯ Compared to clinical assessment, sensitivity and specificity in the mailed S-LANSS were 57% (95% CI, 46-69%) and 69% (95% CI, 61-77%), respectively, and in the telephone S-LANSS were 52% (95% CI, 39-64%) and 78% (95% CI, 68-85%), respectively. The sensitivity and specificity of the S-LANSS in both formats were lower than the initial S-LANSS validation study. Differences in survey format and subject population could account for these differences, suggesting that the S-LANSS is best suited as a screening tool and its use to determine the prevalence of neuropathic pain in population studies should be viewed cautiously.
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There are few studies on coping with fibromyalgia (FM). The aim of the present study was to assess the usefulness of a Spanish version of the Chronic Pain Coping Inventory-42 (CPCI-42) in patients with FM. A random sample (N=402) of patients with FM was obtained from the Fibromyalgia Association of Aragon, Spain. ⋯ Task persistence correlated with illness-focused strategies and negative outcomes, indicating that it should be included in the illness-focused group. However, other wellness-focused strategies, including relaxation, exercise, and coping self-statements, were correlated with each other, negatively correlated with depression, and positively correlated with quality of life. Future research directions and clinical implications are discussed.
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Dysmenorrhoea patients experience intense visceral pain during menstruation. Recurrent and/or intense visceral pain can induce facilitation of somatic and visceral nociceptive processing which can lead to viscero-somatic (referred) and viscero-visceral hyperalgesia. Our aim was to study if dysmenorrhoea is associated with hypersensitivity in the referred somatic skin area or in the large bowel, i.e., viscero-visceral hyperalgesia. ⋯ There were no differences in compliance between the groups. These findings suggest that, despite the absence of overt gastro-intestinal symptoms or viscero-somatic sensitisation, dysmenorrhoea patients demonstrate intestinal hypersensitivity. This can be regarded as the result of centrally mediated viscero-visceral hyperalgesia due to recurrent intense menstrual pain.
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CGRP receptor activation has been implicated in peripheral and central sensitization. The role of spinal CGRP receptors in supraspinal pain processing and higher integrated pain behavior is not known. Here we studied the effect of spinal inhibition of CGRP1 receptors on supraspinally organized vocalizations and activity of amygdala neurons. ⋯ In arthritic rats, the antagonists also inhibited the audible and ultrasonic components of vocalizations evoked by noxious stimuli and increased the threshold of hindlimb withdrawal reflexes. The antagonists had no effect on vocalizations and spinal reflexes in normal rats. These data suggest that spinal CGRP1 receptors are not only important for spinal pain mechanisms but also contribute significantly to the transmission of nociceptive information to the amygdala and to higher integrated behavior.
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Randomized Controlled Trial
The effects of the TRPV1 antagonist SB-705498 on TRPV1 receptor-mediated activity and inflammatory hyperalgesia in humans.
TRPV1 is a cation channel activated by a range of noxious stimuli and highly expressed in nociceptive fibres. TRPV1 receptors are involved in pain and sensitisation associated with tissue injury and inflammation; hence, TRPV1 antagonists are potentially useful for the treatment of such pain states. SB-705498 is a potent, selective and orally bioavailable TRPV1 antagonist with demonstrated efficacy in a number of preclinical pain models. ⋯ The magnitude of the pharmacodynamic effects of SB-705498 appeared to be related to plasma concentration. These results indicate that SB-705498, at a clinically safe and well-tolerated dose, has target-specific pharmacodynamic activity in humans. These data provide the first clinical evidence that a TRPV1 antagonist may alleviate pain and hyperalgesia associated with inflammation and tissue injury.