Articles: neuralgia.
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Pain is associated with affective, cognitive and sensory dysfunction. Animal models can be used to observe ethologically relevant behaviours such as thigmotaxis, giving insight into how ongoing sensory abnormalities influence natural rodent behaviours. The amygdala is a complex group of nuclei implicated in the integration and generation of emotional behavioural responses, including those associated with pain, and a region known as the central amygdala is particularly associated with generation of behavioural responses, due to its links to the descending pain modulation pathways; as such, study of amygdalar c-Fos immunoreactivity can help identify the neuronal circuits involved. ⋯ This study provides evidence to support the role of the amygdala in thigmotactic open field behaviour following SNT. WHAT DOES THIS STUDY ADD?: Thigmotaxis and amygdala activation are positively correlated in rats following spinal nerve transection. Behavioural changes seen in sham animals did not correlate with amygdala activation, suggesting amygdala activation is related to nociceptive input. Evoked measures, such as hindpaw withdrawal, are not correlated with either thigmotaxis or amygdala activation, emphasizing the importance of complex behaviours when studying pain.
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Chronic postsurgical pain (CPSP) is an important clinic problem. It is assessed that prevalence of chronic pain extends to 30% but it is contended that there are various risk factors. We aimed to evaluate the prevalence of chronic pain after hysterectomy, risk factors of chronicity, neuropathic features of pain, and sensorial alterations at surgery area. ⋯ Neuropathic symptoms were observed in 90 patients (96.8%). Sensorial alterations as hypoesthesia and hyperesthesia were detected around abdominal scar in 18 patients (19.4%) with pinprick test. Neuropathic symptoms should not be ignored in studies evaluating CPSP and a standard methodology should be designed for studies in this topic.
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Few studies have evaluated single-gene changes modulated by spinal cord stimulation (SCS), providing a narrow understanding of molecular changes. Genomics allows for a robust analysis of holistic gene changes in response to stimulation. ⋯ The process described provides highly significant interconnected genes and pathways responsive to injury and/or electric field in the SC and DRG. Genes in the SC respond significantly to the SCS in both injured and uninjured animals, while those in the DRG significantly responded to injury, and SCS in injured animals.
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A multiplex analysis for profiling the expression of candidate microRNAs (miRNAs), which are small noncoding RNAs that function as key post-transcriptional regulators, may lead to a better understanding of the complex machinery of neuropathic pain. In the present study, we performed a miRNA array analysis using tissues of the dorsal root ganglion (DRG), a primary site for pain processing, obtained from mice with partial sciatic nerve ligation. Among 1135 total miRNAs, 26 miRNAs showed up-regulation (more than 2-fold change) and only 4 miRNAs showed down-regulation (less than 0.5-fold change) in the DRG of nerve-ligated mice. ⋯ Furthermore, the expression level of miR-21, but not those of miR-431 or miR511-3p, was significantly increased in exosomes extracted from blood of nerve-ligated mice. These findings suggest that the increased expression of IL-6-regulated miR-21, miR-431, and miR-511-3p in the DRG and increased exosomal miR-21 extracted from blood after sciatic nerve ligation may play at least a partial role in neuropathic pain. Synapse 70:317-324, 2016. © 2016 Wiley Periodicals, Inc.