European journal of pain : EJP
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Corticomotor excitability has been shown to correlate with motor learning and functional recovery. The aim of the present study was to monitor changes in excitability of the corticomotor pathways induced by neck training and to compare the effects in patients with neck or knee pain and pain-free participants. ⋯ Neck training reduced neuroplastic responsiveness of corticomotor pathways in neck pain patients in contrast to knee pain patients and pain-free participants. Increased attention to adaptive and maladaptive neuroplastic responses induced by training may prove valuable in the process of optimizing clinical outcomes.
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Heterotopic and homotopic nociceptive conditioning stimulation: Distinct effects of pain modulation.
Within an area, habituation and sensitization represent well-established modulatory effects to repetitive noxious input. Less is known regarding the nociceptive conditioning effects between body sites - i.e., how stimulating one site may affect another. Therefore, we investigated the effects of nociceptive stimulation of anatomically distinct locations (shoulder and hand) on pain rating and evoked potentials (i.e., contact heat-evoked potentials). ⋯ Overall, these findings indicate that response modulation to noxious contact heat stimulation depends upon conditioning stimulus location. These effects represent changes beyond conventional habituation due to repeated stimulation in the same area.
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In patients with chronic non-malignant pain (CNMP), co-morbid physical or mental health disorders are common and may have a negative impact on health-related quality of life and treatment outcomes. The purpose of this study was to examine the occurrence of chronic psychiatric and somatic diseases in persistent opioid users with CNMP compared with the general population in Norway. ⋯ A higher occurrence of both somatic and psychiatric co-morbidities in disease stages warranting pharmacological treatment was found in persistent opioid users with CNMP compared with the general population of Norway.
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The alkaloid morphine is historically the oldest opiate, yet still today it has clinically important uses in analgesic therapies. The main analgesic effect of opioids, including synthetic opioids belonging to the family of 4-anilidopiperidines, is mediated via activation of opioid receptors spread throughout the peripheral and central nervous system. However, morphine acting as a 'dirty' drug also exhibits effects on other receptor systems, e.g., the serotonergic system and its 5-HT3 receptor. Therefore, this study focuses on the interaction of morphine and fentanyl-type opioids (alfentanil, remifentanil and sufentanil) with 5-HT3A receptors. ⋯ Morphine is an opioid compound exhibiting special antagonistic interaction with 5-HT3A receptors. This interaction is not shared by the newer synthetic derivatives of the fentanyl-type opioids in the clinical relevant concentration range.
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A multi-mechanistic approach offers potential enhancement of analgesic efficacy, but therapeutic gain could be offset by an increase in adverse events. The centrally acting analgesic tapentadol [(-)-(1R,2R)-3-(3-dimethylamino-1-ethyl-2-methyl-propyl)-phenol hydrochloride] combines μ-opioid receptor (MOR) agonism and neuronal noradrenaline reuptake inhibition (NRI), both of which contribute to its analgesic effects. Previously, isobolographic analysis of occupation-effect data and a theoretically equivalent methodology determining interactions from the effect scale demonstrated pronounced synergistic interaction between the two mechanisms of action of tapentadol in two models of antinociception (low-intensity tail-flick and spinal nerve ligation). The present study investigated the nature of interaction of the two mechanisms on a surrogate measure for gastrointestinal adverse effect (inhibition of gastrointestinal transit). ⋯ We believe this is the first published evaluation of mechanistic interaction for a surrogate measure of adverse effect of a single compound with two mechanisms of action, and the results suggest that there is a greater separation between the analgesic and gastrointestinal effects of tapentadol than expected based upon its analgesic efficacy.