Pain
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This study investigated the antinociceptive effect of opioids given via intraperitoneal and intrathecal routes in a diabetes-induced neuropathic pain model in rats. Streptozotocin induced diabetes in 91% of juvenile male Wistar rats at the dose of 150 mg/kg (75 mg/kg intraperitoneal on 2 successive days). When compared with younger weight-matched saline treated rats, the diabetic rats developed hyperalgesia assessed by the paw pressure nociceptive test. ⋯ Intrathecal injections of fentanyl (0.05-0.5 microg) in non-neuropathic rats, produced a spinally-mediated, dose-related antinociceptive effect assessed by all tests. In contrast, intrathecal administration of fentanyl that confined the drug action to the spinal cord produced little antinociceptive effect in neuropathic rats in all three tests. These experiments suggest that supraspinal mu opioid receptors are responsible for the antinociceptive effect of opioids in this model of neuropathic pain and that spinal cord opioid systems are in some way rendered ineffective for antinociception assessed with noxious heat, electrical and pressure stimuli.
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We have previously shown in rats that the provision of analgesic doses of morphine significantly reduces the tumor-promoting effects of undergoing and recovering from surgery. Because morphine had no effect in non-operated animals, and because a single preoperative dose given hours before tumor inoculation was effective, we have suggested that it is the pain-relieving effects of the drug that underlies its beneficial impact. To support and strengthen this suggestion, two different regimens of analgesia were employed, the systemic administration of the more selective mu-agonist, fentanyl, and the intrathecal (i.t.) administration of bupivacaine plus morphine. ⋯ Unlike the in vivo study, fentanyl suppressed NK activity at this time point in non-operated rats, but had no effect in operated rats. Taken together, these findings strengthen the suggestion that the management of perioperative pain is a critical factor in preventing surgery-induced decreases in host resistance against metastasis. If similar relationships between pain and metastasis occur in humans, then pain control must become a priority in the postoperative care of individuals with cancer.
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Randomized Controlled Trial Clinical Trial
Heat, but not mechanical hyperalgesia, following adrenergic injections in normal human skin.
The development of adrenergic sensitivity in nociceptors has been suggested as a mechanism of neuropathic pain. We sought to determine if nociceptors in the skin of normal subjects exhibit adrenergic sensitivity. We investigated the effects of intradermal administration of norepinephrine, phenylephrine, and brimonidine on heat pain sensitivity. ⋯ In addition, occlusion of blood flow with a blood pressure cuff did not lead to heat hyperalgesia. Thus, the heat hyperalgesia observed with the adrenergic agonists is not due to a decrease in perfusion associated with the injection. These results indicate that alpha(1)- and alpha(2)-adrenoceptor-mediated mechanisms may play a role in sensitization of nociceptors to heat stimuli in normal skin.
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Randomized Controlled Trial Clinical Trial
A cognitive-behavioral group intervention as prevention for persistent neck and back pain in a non-patient population: a randomized controlled trial.
Given the demand for interventions that may prevent the development of persistent musculoskeletal pain problems, we investigated the effects of a cognitive-behavioral program in a group of non-patients with neck or back pain symptoms. Two hundred and fifty-three people selected from a population study were invited to participate. These people had experienced four or more episodes of relatively intense spinal pain during the past year but had not been out of work more than 30 days. ⋯ Group comparisons indicated that the cognitive-behavioral group, relative to the comparison group, had significantly better results with regard to fear-avoidance beliefs, number of pain-free days, as well as the key variable of sick leave. Participation in the cognitive behavioral group reduced the risk for long-term sick leave during the follow-up by threefold. Thus, despite the strong natural recovery rate for back pain, the cognitive-behavioral intervention produced a significant preventive effect with regard to disability.
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The effectiveness of cognitive-behavior therapy aimed at helping patients with the acquisition of self-management skills to cope with pain, is thought to depend partly on the patients' willingness to adopt a self-management approach. Some patients may not believe that self-management will be helpful while others have decided to adopt it and others already apply the self-management skills in their daily lives. The present study explored the concept of 'Readiness to change' in a population of Dutch fibromyalgic patients. ⋯ These subscales explained 5, 22 and 8% of the variance of the scores on the Precontemplation, Contemplation and the Action scales, respectively. Thirdly, on the basis of the three scale scores, over 80% of the fibromialgia patients could be classified into one of five potentially psychological relevant subgroups: Precontemplation, Contemplation, Preparation, Action and Relapse. The data suggest that improvements in operationalizations of the Precontemplation and Action dimensions of readiness to change are needed and that the theoretical foundation of readiness to change needs further development.