Pain
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Intrathecal administration of serotonin type 2 (5-HT(2)) receptor agonists, alpha-methyl-5-hydroxytryptamine maleate (alpha-m-5-HT) or (+/-)-1-(4-iodo-2,5-dimethoxyphenyl)-2-aminopropane hydrochloride (DOI), produces antiallodynic effects in a rat model of neuropathic pain. In the present study, we examined the antiallodynic effects of intrathecally administered agents which are selective for 5-HT(2C) receptors. Allodynia was produced by tight ligation of the left L5 and L6 spinal nerves, and was measured by applying von Frey filaments to the left hindpaw. ⋯ The preferential 5-HT(2A) receptor antagonist ketanserin (30 microg) did not reverse the effects. In contrast to 5-HT(2C) receptor agonists, the antiallodynic effects of intrathecally administered alpha-m-5-HT (30 microg) and DOI (100 microg) were reversed by ketanserin, but not by RS-102221. These results indicate that 5-HT(2C) receptors have a role in spinal inhibition of neuropathic pain, and the effects produced by intrathecal administration of 5-HT(2C) receptor agonists are mediated by a mechanism different from that of alpha-m-5-HT or DOI, which seem to produce their effects through 5-HT(2A) receptors.
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Randomized Controlled Trial Comparative Study Clinical Trial
A randomized trial of electronic versus paper pain diaries in children: impact on compliance, accuracy, and acceptability.
Electronic diary assessment of pain and disability has become increasingly popular in adult chronic pain research but use of this methodology with children has received limited attention. The aim of this study was to compare two formats of a prospective daily diary (handheld computer=e-diary; paper diary=p-diary) on children's compliance, accuracy, and acceptability ratings. Sixty children, ages 8-16 (M=12.3) with headaches or juvenile idiopathic arthritis, were randomized to receive either e-diaries administered via home visits (n=30) or p-diaries (n=30) handed out during clinic visits for return by mail. ⋯ Children rated both diary formats as highly acceptable and easy to use. A significant gender x diary format interaction (P<0.01) was found for compliance where boys demonstrated greater compliance with the e-diary format. Findings demonstrated that the e-diary was feasible to use with children and showed significantly greater compliance and accuracy in diary recording compared to traditional paper diaries in a population of children with recurrent pain.
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Randomized Controlled Trial Comparative Study Clinical Trial
Communicative dimensions of pain catastrophizing: social cueing effects on pain behaviour and coping.
The study was designed to assess whether the social context of a pain experience impacted on the relation between catastrophizing and duration of pain behaviour. Based on a communal coping model, the prediction was that the presence of an observer during a pain procedure would differentially influence the display of pain behaviour in high and low catastrophizers. University undergraduates taking part in a cold pressor procedure were randomly assigned to one of two conditions: (1) participant alone (n=30), or (2) observer present (n=34). ⋯ When the observer was present, high catastrophizers also reported using fewer cognitive coping strategies than low catastrophizers. The pattern of findings suggests that in the presence of an observer, high pain catastrophizers show a propensity to engage in strategies that more effectively communicate their pain, and are less likely to engage in strategies that might minimize pain. Theoretical implications of the findings are discussed.
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Comparative Study
Effects of stimulus duration on heat induced pain: the relationship between real-time and post-stimulus pain ratings.
Pain is a temporally dynamic experience. Yet, in most instances, pain ratings are acquired in a static fashion and frequently require subjects to retrospectively evaluate the pain experience that occurred in a preceding interval of time. In order to determine which components of the real-time experience of pain contribute to static pain ratings, we obtained real-time (dynamic) and post-stimulus (static) ratings using a visual analogue scale during various of durations (5-30 s) of noxious thermal stimulation (43-49 degrees C). ⋯ Regression analyses examining both pain-intensity and pain-unpleasantness revealed that the mean response and the peak response of real-time ratings significantly contributed to post-stimulus ratings, while temporal components such as perceived duration of pain contributed minimally. Additional regression analyses revealed that mean and peak responses of real-time intensity ratings accounted for much of the variability of post-stimulus unpleasantness ratings whereas real-time unpleasantness ratings accounted for somewhat less of the variability of post-stimulus intensity ratings. Taken together, the close relationship between real-time and post-stimulus ratings of pain across stimulus conditions evoking both adaptation and temporal summation further confirms that post-stimulus, retrospective ratings of pain are valid measures of the real-time experience of pain.