European journal of pain : EJP
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The aim of the present study was to investigate supraspinal modulation of human lower limb reflex receptive fields (RRFs) on the plantar side of the foot during cognitive tasks either distracting the subjects or actively directing their attention to the electrical stimuli directed to the sole of the foot. ⋯ The size of the RRF area was modulated by the cognitive state demonstrating a link between the cognitive activity and the descending control on spinal withdrawal reflex pathways.
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Activation of the prefrontal cortex occurs during acute and chronic pain and models of experimental hyperalgesia. The present study was carried out to determine possible miRNA changes in the prefrontal cortex, after inflammatory pain induced by facial carrageenan injection in mice. miRNA microarray analyses showed significantly increased levels of miR-155 and miR-223 in the prefrontal cortex of carrageenan-injected mice. The changes were verified by real-time RT-PCR, and shown to occur bilaterally. ⋯ Significantly downregulated c/ebp Beta but upregulated GCSF, accompanied by increased immunolabeling with an antibody to myeloperoxidase were found in the prefrontal cortex of facial carrageenan treated mice. It is postulated that this could lead to increased inflammation and activation of the prefrontal cortex. Further studies are necessary to determine if specific miRNAs could be useful as therapeutic molecules for pain.
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The aim of the present study was to compare the subjectively reported and objectively assessed activity-related characteristics of patients with Chronic Low Back Pain (CLBP) who were classified according to their scores on the Patterns of Activity Measure-Pain (POAM-P) into avoiders, persisters, mixed performers (i.e. high scores on both avoidance and persistence behaviour) or functional performers (i.e. low scores on avoidance and persistence behaviour). Patients carried an electronic diary during 14 days to assess the self-reported activity and pain intensity levels in daily life. An accelerometer was used to objectively assess their activity level during the same time period. ⋯ A further analysis tested the association between pain intensity levels and self-reported and objectively assessed daily life activity levels in avoiders and persisters. In persisters, a higher level of self-reported activities in daily life was related to increased pain. The objectively assessed activity level was not associated with pain intensity.
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This study examined differences between Asians and non-Hispanic Whites (Whites) in pain sensitivity, and its relationship to mean arterial pressure (MAP) and heart rate (HR). In 30 Whites (50% female) and 30 Asians (50% female), experimental pain sensitivity was assessed with a hand cold pressor task, yielding measures of pain threshold, tolerance, intensity, and unpleasantness. Mean arterial pressure and HR measurements taken at rest and in response to speech stress were assessed. ⋯ These results indicate that Asian Americans are more sensitive to experimental pain than Whites and suggest ethnic differences in endogenous pain regulatory mechanisms (e.g. MAP and HR). The results may also have implications for understanding ethnic differences in clinical pain.