European journal of pain : EJP
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There is evidence that sensitivity to noxious stimuli differs between the sexes and across the body, but few studies have investigated differences in the perception and experience of acute pain stimuli across the body in healthy individuals. ⋯ Moreover, these insights are helpful for the design of studies investigating pain experience in healthy persons in experimental or clinical settings. WHAT DOES THIS STUDY ADD?: We tested sensitivity to acute suprathreshold thermal stimulations across a range of body sites to investigate for potential variability. We found significant differences in the perceived intensity and unpleasantness of noxious and innocuous thermal stimuli at the wrist and lower back, compared with the shoulder and leg. These results suggest that pain experience is driven by receptor density or the relative functional importance of these sites.
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Pain perception in others can be influenced by different contextual factors. In clinical settings, the repeated exposure to others' pain has been proposed as a factor that could explain underestimation of patients' pain by health care providers. Previous research supported this idea by showing that repeated exposure to persons in pain biases the subsequent willingness to impute pain in others. However, it remains unclear if the effect of repeated exposure on the detection of pain extends to deliberate pain estimation of stimuli presented for a longer period. ⋯ By demonstrating that repeated exposure to others' pain diminished subsequent pain estimation in others, this study adds relevant information on the factors that could contribute to pain underestimation in health care professionals. WHAT DOES THIS STUDY ADD?: Repeated exposure to facial expressions of intense pain not only biases pain detection, but also pain estimation in others. Prior exposure to facial expressions of pain compared to exposure to neutral ones leads to a reduced estimation of others' pain. This effect is not specific to pain as exposure to another negative emotion (fear) also biases subsequent pain estimation. These results support the interpretation that the underestimation of patients' pain by health care professionals could be related to repeated exposure to other's pain.
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Amylin is a peptide from the calcitonin gene-related peptides (CGRP) family that is expressed by nociceptors. Amylin may modulate pain via a spinal action. ⋯ Overall, data suggested that amylin modulates pain with an inflammatory component and the autoanalgesic/inhibitory mechanisms occurring in the interphase of the formalin test. Amylin might have affected the nociceptive system at different levels (spinal cord and brain), explaining the different effects observed according to the time of amylin injection. WHAT DOES THIS STUDY ADD?: Amylin modulated formalin interphase and tonic pain behaviours probably by targeting spinal neurons and affecting supraspinal areas involved in affective and modulatory components of pain. Activation of spinal amylin-receptors may contribute to the initiation of inflammatory pain mechanisms.