European journal of pain : EJP
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The glial cell's role in antinociceptive differential effects of oxytocin upon female and male rats.
Sex plays a crucial role in pain processing and response to analgesic drugs. Indeed, spinal glia seems to be significant in the sexual dimorphism observed in the above effects. Recently, studies have associated oxytocin with antinociceptive effects, but these have been mainly performed in male animals; consequently, the influence of sex has been poorly explored. ⋯ Oxytocin is a molecule that emerges as a potent analgesic in preclinical and clinical studies. We investigated the contribution of glia to the response of oxytocin-induced analgesia and how sex influences in this response show that different strategies are required to treat pain in men and women, and that oxytocin could be used preferentially to treat pain with a significant inflammatory component in men.
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Chronic primary low back pain may be associated with hyperalgesia in uninjured tissues and with decreased pain inhibition. Previous studies have shown that the amygdala is involved in pain regulation and chronic pain, that neuronal activity in the amygdala is altered in models of persistent pain, and that the central nucleus of the right amygdala plays an active role in widespread hypersensitivity to noxious stimuli. ⋯ The amygdala is a key structure involved in pain perception and modulation. The present results indicate that the GABAergic neurons of its central nucleus are involved in widespread hypersensitivity to noxious stimuli in a rat model of chronic back pain. The inhibition of amygdala GABAergic neurons may be a potential target for future interventions in patients with chronic back pain.
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The early identification of factors that increase risk of poor recovery from acute low back pain (LBP) is critical to prevent the transition to chronicity. Although most studies of risk factors for poor outcome in LBP tend to investigate the condition once it is already persistent, there is evidence to suggest that this differs from risk factors measured during the early-acute stage. This study aimed to identify early risk factors for poor outcome in the short- and long-term in individuals with acute LBP, and to compare this with factors identified at 3 months in the same cohort. ⋯ The results highlight the multidimensional nature of risk factors for poor outcome in LBP and the need to consider time variation in these factors. Significance This study attempts to consider the impact of time variation of candidate risk factors on long-term outcome from the very early onset of acute low back pain. Risk factors across domains (sociodemographic, psychological, clinical, history/treatment) were identified, but their relationship with outcome often depended on when (acute phase vs. 3 months later) they were measured after back pain onset. Findings highlight the need to consider both a diverse range of factors and their potential time variance when assessing risk of poor outcome.
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Observational Study
Association of Pre-operative Functional Disability with Chronic Postsurgical Pain: A Prospective Observational Study.
Chronic postsurgical pain negatively affects postoperative recovery. We aimed to assess the association between preoperative functional disability and chronic postsurgical pain. ⋯ Our study showed that in patients who undergo elective abdominal surgery, 12% with preoperative functional disability experience chronic postsurgical pain after 1 year. Preoperative functional disability is associated with chronic postsurgical pain, use of preoperative pain medications and acute postoperative pain. Patients with preoperative functional disability have higher pain numerical rating scale scores at any postoperative measurement point.