Pain
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Accumulating evidence suggests an important contribution of reactive oxygen species (ROS) to pain and neuropsychiatric disorders, but their role in pain-related plasticity in the brain is largely unknown. Neuroplasticity in the central nucleus of the amygdala (CeA) correlates positively with pain behaviors in different models. Little is known, however, about mechanisms of visceral pain-related amygdala changes. ⋯ Whole-cell patch-clamp recordings of CeA neurons in brain slices from zymosan-treated rats showed that tempol decreased neuronal excitability and excitatory synaptic transmission of presumed nociceptive inputs from the brainstem (parabrachial area) through a combination of presynaptic and postsynaptic actions. Tempol had no effect in brain slices from sham controls. The results suggest that ROS contribute to visceral pain-related hyperactivity of amygdala neurons and amygdala-dependent behaviors through a mechanism that involves increased excitatory transmission and excitability of CeA neurons.
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Comparative Study
Disease-Related Differences in Resting State Networks: A Comparison between Localized Provoked Vulvodynia, Irritable Bowel Syndrome, and Healthy Control Subjects.
Localized provoked vulvodynia (LPVD) affects approximately 16% of the female population, but biological mechanisms underlying symptoms remain unknown. Like in other often comorbid chronic pain disorders, altered sensory processing and modulation of pain, including central sensitization, dysregulation of endogenous pain modulatory systems, and attentional enhancement of pain perception, have been implicated. The aim of this study was to test whether regions of interest showing differences in LPVD compared to healthy control subjects (HCs) in structural and evoked-pain neuroimaging studies, also show alterations during rest when compared with HCs and a chronic pain control group (irritable bowel syndrome [IBS]). ⋯ Findings were robust to controlling for affect and medication usage. The current findings indicate that subjects with LPVD have alterations in the intrinsic connectivity of regions comprising the sensorimotor, salience, and default mode networks. Although shared brain mechanisms between different chronic pain disorders have been postulated, the current findings suggest that some alterations in functional connectivity may show disease specificity.
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Randomized Controlled Trial Multicenter Study
Imipramine and Pregabalin Combination for Painful Polyneuropathy. A Randomized Controlled Trial.
Monotherapy with first-line drugs for neuropathic pain often fails to provide sufficient pain relief or has unacceptable side effects because of the need for high doses. The aim of this trial was to test whether the combination of imipramine and pregabalin in moderate doses would relieve pain more effectively than monotherapy with either of the drugs. This was a randomized, double-blind, placebo-controlled, crossover, multicenter trial consisting of four 5-week treatment periods in patients with painful polyneuropathy. ⋯ During combination therapy, the dropout rate was higher and the patients reported a higher rate and severity of side effects. Combination of moderate doses of the tricyclic antidepressant imipramine and pregabalin could be considered as an alternative to high-dosage monotherapy. However, the trial also emphasized that balance between efficacy and safety is an issue.
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Randomized Controlled Trial
Automated, Internet-based Pain Coping Skills Training to Manage Osteoarthritis Pain: A Randomized Controlled Trial.
Osteoarthritis (OA) places a significant burden on worldwide public health because of the large and growing number of people affected by OA and its associated pain and disability. Pain coping skills training (PCST) is an evidence-based intervention targeting OA pain and disability. To reduce barriers that currently limit access to PCST, we developed an 8-week, automated, Internet-based PCST program called PainCOACH and evaluated its potential efficacy and acceptability in a small-scale, 2-arm randomized controlled feasibility trial. ⋯ Additionally, both men and women demonstrated increases in self-efficacy from baseline to after intervention compared with the control group (d = 0.43). Smaller effects were observed for pain-related anxiety (d = 0.20), pain-related interference with functioning (d = 0.13), negative affect (d = 0.10), and positive affect (d = 0.24). Findings underscore the value of continuing to develop an automated Internet-based approach to disseminate this empirically supported intervention.