Pain
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We investigated the participation of cyclin-dependent kinase-5 (Cdk5)-mediated N-methyl-D-aspartate receptor (NMDAR) NR2B subunit phosphorylation in cross-organ reflex sensitization caused by colon irritation. The external urethral sphincter electromyogram (EUSE) reflex activity evoked by the pelvic afferent nerve test stimulation (TS, 1 stimulation/30s) and protein expression in the spinal cord and dorsal root ganglion tissue (T13-L2 and L6-S2 ipsilateral to the stimulation) in response to colon mustard oil (MO) instillation were tested in anesthetized rats. ⋯ Moreover, compared with the control group, both the increase in pNR2B and the cross-organ reflex sensitization were attenuated in the si-RNA of NR2B rats. All these results suggested that Cdk-dependent NMDAR NR2B subunit phosphorylation mediates the development of cross-organ pelvic-urethra reflex sensitization caused by acute colon irritation which could possibly underlie the high concurrence of pelvic pain syndrome with irritable bowel syndrome.
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Randomized Controlled Trial Controlled Clinical Trial
No evidence for the development of acute tolerance to analgesic, respiratory depressant and sedative opioid effects in humans.
It is widely accepted that chronic opioid therapy is associated with the development of pharmacological tolerance. More controversial is the question as to whether acute opioid administration can result in "acute tolerance." The aim of this double-blind, placebo-controlled study in thirty-six healthy human volunteers was to examine whether a 3-h intravenous infusion delivering two different but clinically relevant doses of the mu-opioid receptor agonist remifentanil would result in tolerance to analgesic, respiratory depressant and/or sedative opioid effects. The blood remifentanil concentration versus opioid effect relationship was determined before and after the 3-h infusion. ⋯ Neither dose of remifentanil produced detectable tolerance to any of the measured opioid effects following a 3-h infusion. The study was adequately powered to detect a decrease in potency of 5-24% for analgesia, 20-48% for respiratory depression, and 32% for sedative effects. These results suggest that short-term administration of clinically useful doses of remifentanil is not associated with the development of significant tolerance to analgesic, respiratory depressant, or sedative opioid effects.
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Randomized Controlled Trial
The effect of attentional re-training and threat expectancy in response to acute pain.
This study aimed to investigate the efficacy of implicit attention re-training (AR) on pain ratings, threshold and tolerance during the cold-pressor task and to determine whether the effectiveness of AR was affected by threat expectancy. One hundred and four undergraduate psychology students were randomly assigned to receive either threat-alleviating or threat-inducing information about the task. Participants were then re-randomized to receive an AR that either trained them to implicitly attend to neutral and ignore pain-related stimuli (neutral training) or to attend towards pain-related stimuli (pain training). ⋯ For initial pain ratings, there was an interaction that closely approached significance (p=0.053). These results show that AR affects individual's perceptions of and their responses to pain during an experimental task in a similar way to increasing the threat expectancy of the task. Future research should trial AR in real-life settings to determine whether these results can be generalized.
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The objective of our study is to evaluate the detection capacity of Colour Duplex Scanning (CDS) in helping to diagnose Pudendal Neuralgia (PNa) by Pudendal Nerve Entrapment (PNE). This technique is being compared to complete Neurological Criteria (NC) based on Diagnostic Score (DS) and Electroneuromyography (ENMG) and secondly, to the results of surgery. This is a prospective study, on a consecutive series of 96 unselected patients evaluated by both CDS and NC. ⋯ Currently, there is no gold standard that can diagnose PNa by PNE with certainty. CDS is a non-invasive technique, demonstrating high diagnostic value to confirm PNE. In this study, we determined a new objective diagnostic criterion, the Pudendal Artery Ratio (PAR), which is very strong at diagnosing PNE but needs to be validated by further studies.