The journal of pain : official journal of the American Pain Society
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Altered nociception, a key feature of nociplastic pain, often involves central sensitization. We previously found that central sensitization underlying a nociplastic pain state in female mice depends on the ongoing activity of TRPA1 agonist-responsive afferents. Here, we investigated how the activity of these afferents induces and maintains central sensitization at the spinal level. ⋯ These results suggest that the activity of TRPA1 agonist-responsive afferents induces and maintains central sensitization by activating dorsal horn SSTn and suppressing GABAn via SST2A-R, resulting in altered nociception that manifests as mechanical hypersensitivity. PERSPECTIVE: This article presents experimental evidence that TRPA1 agonist-responsive afferents induce and maintain central sensitization at the spinal level by activating SST-expressing excitatory interneurons and suppressing GABAergic inhibitory interneurons via SST2A-R. Spinal SST2A-R may represent a promising target for treating mechanical pain hypersensitivity due to central sensitization by TRPA1 agonist-responsive afferents.
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Comparative Study
Comparison of Measures of Pain Intensity during Sickle Cell Disease Vaso-Occlusive Episodes.
We aimed to determine the minimal clinically important difference (MCID) in pain severity and agreement between the visual analog scale (VAS) and the verbal numeric rating scale (NRS) in people with sickle cell disease (SCD) experiencing an acute vaso-occlusive episode in the emergency department. In the COMPARE-VOE trial (NCT03933397), participants were administered the VAS (0-100), NRS (0-100), and descriptor scale (a lot better, a little better, same, a little worse, much worse) every 30 minutes while in the emergency department. We analyzed data from 100 participants (mean age 30.2 years; 61% female). ⋯ Despite high correlation, there was considerable variability of agreement between the VAS and NRS scales, indicating that these scales are not interchangeable to assess pain during a vaso-occlusive event. PERSPECTIVE: The MCID in pain severity for individuals with a SCD vaso-occlusive episode using the VAS (8.77 mm) is lower than previously reported, and the MCID for NRS was 8.29. The agreement between the VAS and NRS was determined and the scales cannot be used interchangeably to measure SCD pain intensity.
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Among the methods for cognitive control of pain, the suggestions for analgesia-direct or indirect-have been widely and successfully used in experimental and clinical trials. The primary aim of this study was to contribute to the debate about the difference in the effectiveness of indirect and direct suggestions for the management of experimental pain in the ordinary state of consciousness. The secondary aim of the study was to ascertain the role of hypnotizability and expectation of pain relief in the suggestions' effect. ⋯ The results showed that both direct and indirect suggestions increase the threshold of experimental pain and that the expectation of pain relief is relevant only to the effect of direct suggestions. PERSPECTIVE: Although the reported findings cannot be extended to clinical pain, they suggest that indirect suggestions can be effective independently from the expectation of pain relief, thus evading the possible negative effects of traits such as catastrophism or reactance. Thus, indirect suggestions should be preferred in clinical contexts.
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Review Meta Analysis
Acupuncture Provides Short-term Functional Improvements and Pain Relief for Patients after Knee Replacement Surgery: A Systematic Review and Meta-analysis.
The impact of acupuncture on knee function and pain intensity following knee replacement remains controversial. Therefore, we categorized the postsurgery recovery period into 3 phases: short-term (≤2 weeks), intermediate-term (2 weeks-3 months), and long-term (>3 months), and then assessed the effectiveness of acupuncture in improving function and alleviating pain at different stages following knee replacement. This meta-analysis included randomized controlled trials that compared acupuncture intervention with either no treatment or a sham group after knee replacement. ⋯ PERSPECTIVE: This article demonstrates that acupuncture has short-term effects (≤2 weeks) on improving active range of motion and reducing pain during rest and during movement following knee replacement surgery. The findings support the early application of acupuncture in hospital settings after knee replacement. REGISTRATION ID: The study was registered on PROSPERO (CRD42024503479).
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Review Meta Analysis
The effect of experimentally induced pain in the cervical, shoulder or orofacial regions on cervical neuromuscular and kinematic features: a systematic review and meta-analysis.
In this systematic review, we synthesize the literature investigating the effect of experimentally induced pain in the cervical, shoulder, or orofacial regions on cervical neuromuscular and kinematic features. Databases were searched up to November 1, 2023. A total of 29 studies using hypertonic saline injection (n = 27) or glutamate injection (n = 2) as experimental pain models were included. ⋯ PERSPECTIVE: This systematic review and meta-analysis revealed a reduced or unchanged muscle activation during experimental pain in the cervical, shoulder, or orofacial regions, depending on the task and location of nociceptive stimulation. There was inconsistent evidence on cervical kinematics. These findings enhance our understanding of neuromuscular adaptations to acute experimental pain.