Pain

Lateral and ventral lateral subregions of the periaqueductal gray (l/vlPAG) have been proved to be pivotal components in descending circuitry of itch processing, and their effects are related to the subclassification of neurons that were meditated. In the present study, lateral parabrachial nucleus (LPB), one of the most crucial relay stations in the ascending pathway, was taken as the input nucleus to examine the modulatory effect of l/vlPAG neurons that received LPB projections. Anatomical tracing, chemogenetic, optogenetic and local pharmacological approaches were utilized to investigate the participation of the LPB-l/vlPAG pathway in itch and pain sensation in mice...

UVB irradiation induces hyperalgesia in human and animal pain models. We investigated mechanical sensitization, increase in axonal excitability and spontaneous activity in different C-nociceptor classes following UVB in pig skin. We focused on units with receptive fields covering both irradiated and non-irradiated skin allowing intra-individual comparisons. 35 pigs were irradiated in a chessboard pattern and extracellular single-fibre recordings were obtained 10-28 h later (152 fibers). Units from the contralateral hindlimb served as control (n=112)...

While knee and hip replacements are intended to relieve pain and improve function, up to 44% of knee replacement patients and 27% of hip replacement patients report persistent postoperative joint pain. Improving surgical pain management is essential. We conducted a single-site, three-arm, parallel-group randomized clinical trial conducted at an orthopedic clinic, among patients undergoing total joint arthroplasty (TJA) of the hip or knee. Mindfulness meditation (MM), hypnotic suggestion (HS), and cognitive-behavioral pain psychoeducation (CBE) were each delivered in a single, 15-minute group session as part of a 2-hour, preoperative education program...

Pain is a frequent reason for patients to ask for medical services. However, systematic information about the extent and impact of pain, especially in developing countries, has not been available up to now. We evaluated, whether the 11th edition of the ICD can fill this gap by coding all electronic out-patient medical records of the pain clinic at Siriraj Hospital in Thailand in 2019 (8714 visits), using the ICD-10 and ICD-11 browsers referenced on the WHO websites. The three most frequent pain-related codes in ICD-10 were R52...

It remains unknown why upon similar acute/subacute painful conditions, pain persists in some individuals while in others it resolves. Genetic factors, mood, and functional alterations, particularly involving the mesolimbic network, appear to be key. In order to explore potential susceptibility/resistance factors, we screened a large population of rats with a peripheral neuropathy and we isolated a small subset (<15%) that presented high thresholds (HT) to mechanical allodynia (reduced pain manifestation)...

High-definition transcranial direct current stimulation (HD-tDCS) of brain areas related to pain processing may provide analgesic effects evident in the sensory detection and pain thresholds. The somatosensory sensitivity was assessed following HD-tDCS targeting the primary motor cortex (M1) and/or the dorsolateral prefrontal cortex (DLPFC). Eighty-one (40 females) subjects were randomly assigned to one of four anodal HD-tDCS protocols (20 min) applied on three consecutive days: Sham-tDCS, DLPFC-tDCS, M1-tDCS, and DLPFC&M1-tDCS (simultaneous tDCS of DLPFC and M1)...

Translational regulation permeates neuronal function. Nociceptors are sensory neurons responsible for the detection of harmful stimuli. Changes in their activity, termed plasticity, are intimately linked to the persistence of pain. While inhibitors of protein synthesis robustly attenuate pain associated behavior, the underlying targets that support plasticity are largely unknown. Here, we examine the contribution of protein synthesis in regions of RNA annotated as non-coding. Based on analyses of previously reported ribosome profiling data, we provide evidence for widespread translation in non-coding transcripts and regulatory regions of mRNAs...

Adolescent knee pain has a propensity for chronicity, impacting physical activity and health into adulthood. The aim of this study is to investigate prognostic factors in adolescents with knee pain using Individual Participant Data (IPD) meta-analysis. Studies were identified through a systematic search and a collaborative group. We included IPD from prospective studies of adolescents (age 10 - 19 years) with non-traumatic knee pain (13 studies and 1516 adolescents with 1281 unique participants). Primary outcomes were pain intensity and function (Knee Injury and Osteoarthritis Outcome Score "Sport/Rec" subscale)...

Placebo effects have traditionally involved concealment or deception. However, recent evidence suggests that placebo effects can also be elicited when prescribed transparently as "open-label placebos" (OLP), and that the pairing of an unconditioned stimulus (e.g., opioid analgesic) with a conditioned stimulus (e.g., placebo pill) can lead to the conditioned stimulus alone reducing pain. In this randomized control trial, we investigated whether combining conditioning with an open-label placebo (COLP) in the immediate postoperative period could reduce daily opioid use and postsurgical pain among patients recovering from spine surgery...

When nociceptive stimulation affects a larger body area, pain increases. This effect is called spatial summation of pain (SSp). The aim of this study was to describe SSp as a function of the size or distance of a stimulated area(s) and to test how this function is shaped by the intensity and SSp test paradigm. Thirty-one healthy volunteers participated in a within-subject experiment. Participants were exposed to area- and distanced based SSp. For area-based SSp, electrocutaneous noxious stimuli were applied by up to 5 electrodes (5 areas) forming a line-like pattern; for distance-based SSp, the same position and lengths of stimuli were used but only two electrodes were stimulated...

No abstract text is available yet for this article.

Photobiomodulation therapy (PBMT) has been used in several musculoskeletal disorders to reduce pain, inflammation and promoting tissue regeneration. The current evidence about the effects of PBMT on low back pain are still conflicting. We aimed to evaluate the effects of photobiomodulation therapy against placebo on pain intensity and disability in patients with chronic non-specific low back pain. This was a prospectively registered, randomised placebo-controlled trial, with blinded patients, therapists and assessors...

No abstract text is available yet for this article.

The primary aim of this randomized clinical trial is to investigate the effects of ultrasound guided transversus abdominis plane (TAP) versus ultrasound guided trigger point injections (TPIs) on numerical rating scale (NRS) pain scores at month 3 follow-up in patients with a chronic abdominal wall pain (AWP). The primary outcome measure was the difference in mean numeric rating scale pain scores between the TAP and TPI groups at month 3 in an intent-to-treat (ITT) analysis. A total of 60 patients were randomized 1:1 to receive an ultrasound-guided TAP block (n=30) or an ultrasound-guided TPI (n=30)...

Pain puts patients at risk for developing psychiatric conditions such as anxiety and depression. Pre-clinical mouse models of pain-induced affective behavior vary widely in methodology and results, impairing progress towards improved therapeutics. To systematically investigate the effect of long-term inflammatory pain on exploratory behavior and stress coping strategy, we assessed male C57BL/6J mice in the forced swim test (FST), elevated zero maze (EZM), and open field test (OFT) at four and six weeks post-injection of Complete Freund's Adjuvant (CFA), while controlling for testing order and combination...

Although placebo effect sizes in clinical trials of chronic pain treatments have been increasing, it remains unknown if characteristics of individuals' thoughts or prior experiences can reliably infer placebo pill responses. Research using language to investigate emotional and cognitive processes has recently gained momentum. Here, we quantified placebo response in chronic low back pain using over 300 semantic and psycholinguistic features derived from patients' language. This speech content was collected in an exit interview as part of a clinical trial investigating placebo analgesia (62 patients, 42 treated; 20 not treated)...

Adults are more likely to suffer from chronic pain than minors, and its underlying mechanism remains unclear. SIRT1 as important aging-related protein with function of lifespan extension, whether SIRT1 plays a role in the different pain vulnerability of adult and juvenile remains unclear. Here, we found that the expression level of SIRT1 in dorsal root ganglia (DRG) was related to the pain vulnerability. Following nerve injury, the expression of SIRT1 in DRG was decreased in adult rodents while increased in juvenile rodents...

Alzheimer's disease (AD) is the most common form of dementia, accounting for approximately 60% of cases. In addition to memory loss, changes in pain sensitivity are found in a substantial proportion of AD patients. However, the mechanism of nociception deficits in AD is still unclear. Here, we hypothesize that the nociception abnormality in AD is due to the aberrant activation of striatal-enriched protein tyrosine phosphatase (STEP) signaling, which modulates proteins related to nociception transduction. Our results indicated that the transgenic mice carrying human amyloid precursor protein (APP) gene had lower sensitivity to mechanical and thermal stimulation than the WT group at the ages of 6, 9, and 12 months...

Pain and depression are episodic conditions that might take a chronic course. They are clearly related, but information on how they influence each other in the process of chronification is limited. Pain catastrophizing is hypothesized to play a role in the development of depression and chronic pain, but few longitudinal studies have investigated their association over a longer-term. In this study, a random cohort from the general population (n = 4764) answered questions about pain, catastrophizing, and depression at five assessments in yearly intervals...

Patients with a history of early life stress (ELS) exposure have an increased risk of developing chronic pain and mood disorders later in life. The severity of ELS in patients with urologic chronic pelvic pain syndrome (UCPPS) is directly correlated with symptom severity and increased comorbidity, and is inversely related to likelihood of improvement. Voluntary exercise improves chronic pain symptoms and our group and others have shown that voluntary wheel running can improve outcomes in stress-induced UCPPS models, suggesting that exercise may negate some of the outcomes associated with ELS...