The journal of pain : official journal of the American Pain Society
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Alpha-7 nicotinic acetylcholine receptor (α7 nAChR) agonists attenuate pain and inflammation in preclinical models. This study tested whether systemic delivery of an α7 nAChR agonist attenuates neuropathic pain and associated immune-mediated pro-inflammation. Hind paw response thresholds to mechanical stimuli in male Sprague Dawley rats were assessed before and after sciatic chronic constriction injury (CCI) or sham surgery. Osmotic mini-pumps containing TC-7020, an α7 nAChR selective agonist, were implanted 10 to 14 days after surgery. TC-7020 (1, 3, and 10 mg/kg/d; s.c.) significantly attenuated CCI-induced allodynia, which lasted through 2 weeks of test compound administration. Spinal cords were collected after 2 weeks and processed for microglial and astrocyte activation markers within the ipsilateral L4-L6 dorsal horn. In addition, ipsilateral L4-5 dorsal root ganglia (DRGs) were processed for neuronal injury and satellite cell activation markers. CCI-induced central glial cell activation markers were not suppressed by TC-7020, even though TC-7020 is mildly blood-brain barrier permeable. However, TC-7020 downregulated the integrated density of activation transcription factor 3 (ATF3) but not the number of ATF positive cells. TC-7020 also downregulated phosphorylated extracellular signal kinase (p-ERK) and satellite cell activation in the CCI-affected DRGs. Therefore, systemic α7 nAChR agonist may be effective in treating neuropathic pain via reducing neuronal injury and immune cells activation occurring in the periphery. ⋯ These studies demonstrated that TC-7020, an alpha7 nicotinic acetylcholine receptor agonist with partial blood-brain barrier permeability, reversed neuropathic pain in rats, likely via attenuation of inflammation in the DRG and/or the site of sciatic injury.
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Randomized Controlled Trial
We discount the pain of others when pain has no medical explanation.
The present studies investigated the impact of medical and psychosocial information on the observer's estimations of pain, emotional responses, and behavioral tendencies toward another person in pain. Participants were recruited from the community (study 1: N = 39 women, 10 men; study 2: N = 41 women, 12 men) and viewed videos of 4 patients expressing pain, paired with vignettes describing absence or presence of 1) medical evidence for the pain and 2) psychosocial influences on the pain experience. A similar methodology was used for studies 1 and 2, except for the explicit manipulation of the presence/absence of psychosocial influences in study 2. For each patient video, participant estimations of each patient's pain and their own distress, sympathy, and inclination to help were assessed. In both studies, results indicated lower ratings on all measures when medical evidence for pain was absent. Overall, no effect of psychosocial influences was found, except in study 2 where participants indicated feeling less distress when psychosocial influences were present. The findings suggest that pain is taken less seriously when there is no medical evidence for the pain. The findings are discussed in terms of potential mechanisms underlying pain estimations as well as implications for caregiving behavior. ⋯ The present studies indicate that observers take the pain of others less seriously in the absence of clear medical evidence for the pain. These findings are important to further understand the social context in which pain for which there is no clear medical explanation is experienced.
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Pain is among the most common symptoms of cancer, with impacts on multiple domains of well-being. Biopsychosocial factors play an important role in adjustment to cancer pain. The Communal Coping Model (CCM), which may elucidate the social context of cancer pain, suggests that people catastrophize to convey distress and elicit support. Attachment style, one's ability to elicit and respond to available support, may be an important factor, but this has not been tested in people with cancer pain. This study examined pain catastrophizing, attachment style and relational context in relation to perceived solicitous, distracting, and punishing responses of significant others to pain in 191 patients with advanced cancer. Consistent with the CCM, higher pain catastrophizing was related to more frequent solicitous and distracting responses. Pain catastrophizing, attachment anxiety, and significant other type interacted in relation to punishing responses. Higher pain catastrophizing was related to less frequent punishing responses only in anxiously attached patients who identified their spouse/partner as their significant other. These results provide support for the CCM of cancer pain, and contribute to refinement of the model. Future research that includes patients and their caregivers is required to further explicate the social context of cancer pain. ⋯ This article investigates the Communal Coping Model in people with cancer pain. In partial support of the model, we found that pain catastrophizing was related to more frequent solicitous and distracting responses but less frequent punishing responses only in anxiously attached patients who identified their spouse/partner as their significant other.
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Study purposes were to determine the prevalence of persistent pain in the breast; characterize distinct persistent pain classes using growth mixture modeling; and evaluate for differences among these pain classes in demographic, preoperative, intraoperative, and postoperative characteristics. In addition, differences in the severity of common symptoms and quality of life outcomes measured prior to surgery, among the pain classes, were evaluated. Patients (n = 398) were recruited prior to surgery and followed for 6 months. Using growth mixture modeling, patients were classified into no (31.7%), mild (43.4%), moderate (13.3%), and severe (11.6%) pain groups based on ratings of worst breast pain. Differences in a number of demographic, preoperative, intraoperative, and postoperative characteristics differentiated among the pain classes. In addition, patients in the moderate and severe pain classes reported higher preoperative levels of depression, anxiety, and sleep disturbance than the no pain class. Findings suggest that approximately 25% of women experience significant and persistent levels of breast pain in the first 6 months following breast cancer surgery. ⋯ Persistent pain is a significant problem for 25% of women following surgery for breast cancer. Severe breast pain is associated with clinically meaningful decrements in functional status and quality of life.