Pain
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Cannabinoid receptor agonists produce analgesia for pains of non-cranial origin. However, their effectiveness for craniofacial pains is currently unclear. In the present study, the cannabinoid CB1/CB2 receptor agonist, WIN 55,212-2 (WIN), was bath applied to the brainstem while activity of spinal trigeminal nucleus caudalis (Vc) neurons evoked by transcutaneous electrical stimulation was recorded in isoflurane anesthetized rats. ⋯ SR141716A, a CB1 receptor antagonist, prevented the effects of WIN on WDR PDC and LTM Abeta evoked activity. These results indicate that cannabinoid receptor agonists may be effective agents for craniofacial pain. Furthermore, the particular sensitivity of PDC activity, a measure of neuronal hyperexcitability, to cannabinoid receptor agonists may be relevant to the treatment of persistent craniofacial 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
The role of neuroticism, pain catastrophizing and pain-related fear in vigilance to pain: a structural equations approach.
The present study aimed at clarifying the precise role of pain catastrophizing, pain-related fear and personality dimensions in vigilance to pain and pain severity by means of structural equation modelling. A questionnaire survey was conducted in 122 patients with chronic or recurrent low back pain. Results revealed that pain catastrophizing and pain-related fear mediated the relationship between neuroticism and vigilance to pain. ⋯ Finally, we found that neuroticism moderated the relationship between pain severity and catastrophic thinking about pain. The results strongly support the idea that vigilance to pain is dependent upon catastrophic thinking and pain-related fear. Neuroticism is best conceived of as a vulnerability factor; it lowers the threshold at which pain is perceived as threatening, and at which catastrophic thoughts about pain emerge.
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Randomized Controlled Trial Comparative Study Clinical Trial
Addition of ultralow dose naloxone to postoperative morphine PCA: unchanged analgesia and opioid requirement but decreased incidence of opioid side effects.
Ultralow doses of naloxone (0.001-0.1 microg/kg) produce analgesia in animal models. However, no clinical study has evaluated the combination of ultralow dose naloxone and morphine using patient-controlled analgesia (PCA). This randomized, double blind controlled study sought to determine if the combination of ultralow dose naloxone and morphine in PCA solutions affects opioid requirements, analgesia, and side effects. ⋯ The morphine+naloxone group had a lower incidence of nausea and pruritus than the morphine group (P=0.01 for both symptoms). However, the incidence of vomiting, time to tolerate fluids, sedation, and urinary retention were similar between groups (all P values >0.1). The combination of ultralow dose naloxone and morphine in PCA does not affect analgesia or opioid requirements, but it decreases the incidence of nausea and pruritus.