To focus on pain or not to focus? WHEN is the question
No abstract available (Source: Pain)
Source: Pain - September 26, 2019 Category: Anesthesiology Tags: Commentaries Source Type: research

NaV1.7 and pain: contribution of peripheral nerves: Erratum.
No abstract available (Source: Pain)
Source: Pain - August 21, 2019 Category: Anesthesiology Tags: Erratum Source Type: research

Modulation of brain networks by sumatriptan-naproxen in the inflammatory soup migraine model
Migraine is a debilitating condition; however, the pharmacological effects on central nervous system networks after successful therapy are poorly understood. Defining this neurocircuitry is critical to our understanding of the disorder and for the development of antimigraine drugs. Using an established inflammatory soup model of migraine-like pathophysiology (N = 12) compared with sham synthetic interstitial fluid migraine induction (N = 12), our aim was to evaluate changes in network-level functional connectivity after sumatriptan-naproxen infusion in awake, conscious rodents (Sprague–Dawley rats). Sumatriptan-napro...
Source: Pain - August 21, 2019 Category: Anesthesiology Tags: Research Paper Source Type: research

NLRP2 inflammasome in dorsal root ganglion as a novel molecular platform that produces inflammatory pain hypersensitivity
This study investigated the existence of the inflammasome in dorsal root ganglion (DRG) and the functional significance in the development of inflammatory pain hypersensitivity. Tissue inflammation was induced in male C57BL/6 mice with complete Freund's adjuvant (CFA) or ceramide injection into the hind paw. Behavioral testing was performed to investigate inflammation-induced pain hypersensitivity. Ipsilateral L5 DRGs were obtained for analysis. Expression of nucleotide oligomerization domain-like receptors (NLRs) was analyzed with real-time PCR. Cleaved interleukin (IL)-1β and NLRP2 expression was investigated with i...
Source: Pain - August 21, 2019 Category: Anesthesiology Tags: Research Paper Source Type: research

Longitudinal translocator protein-18 kDa–positron emission tomography imaging of peripheral and central myeloid cells in a mouse model of complex regional pain syndrome
Complex regional pain syndrome (CRPS) is a severely disabling disease characterized by pain, temperature changes, motor dysfunction, and edema that most often occurs as an atypical response to a minor surgery or fracture. Inflammation involving activation and recruitment of innate immune cells, including both peripheral and central myeloid cells (ie, macrophages and microglia, respectively), is a key feature of CRPS. However, the exact role and time course of these cellular processes relative to the known acute and chronic phases of the disease are not fully understood. Positron emission tomography (PET) of translocator pr...
Source: Pain - August 21, 2019 Category: Anesthesiology Tags: Research Paper Source Type: research

High-dose prescribed opioids are associated with increased risk of heroin use among United States military veterans
This study aimed to determine whether dose and duration of opioid prescriptions predict subsequent heroin use in United States veterans. We analyzed data from 2002 to 2012 from the Veterans Aging Cohort Study, a prospective cohort study. We used inverse probability of censoring weighted Cox regression to examine the relationship between self-reported past year heroin use and 2 primary predictors: (1) prior receipt of a high-dose opioid prescription (≥90 mg morphine equivalent daily dose), and (2) prior receipt of a long-term opioid prescription (≥90 days). Heroin use was ascertained using most recent value of time-up...
Source: Pain - August 21, 2019 Category: Anesthesiology Tags: Research Paper Source Type: research

Motor adaptation varies between individuals in the transition to sustained pain
Musculoskeletal pain is associated with altered motor control that, despite short-term benefit, is hypothesised to have long-term consequences, contributing to the development of chronic pain. However, data on how motor control is altered when pain is sustained beyond a transient event are scarce. Here, we investigated motor adaptation, and its relationship with corticomotor excitability, in the transition to sustained muscle pain. Twenty-eight healthy individuals were injected with nerve growth factor into the right extensor carpi radialis brevis muscle on days 0 and 2. Motor adaptation and corticomotor excitability were ...
Source: Pain - August 21, 2019 Category: Anesthesiology Tags: Research Paper Source Type: research

Suppression of neuropathic pain by selective silencing of dorsal root ganglion ectopia using nonblocking concentrations of lidocaine
Neuropathic pain is frequently driven by ectopic impulse discharge (ectopia) generated in injured peripheral afferent neurons. Observations in the spinal nerve ligation (SNL) model in rats suggest that cell bodies in the dorsal root ganglion (DRG) contribute 3 times more to the ectopic barrage than the site of nerve injury (neuroma). The DRG is therefore a prime interventional target for pain control. Since DRG ectopia is selectively suppressed with lidocaine at concentrations too low to block axonal impulse propagation, we asked whether targeted delivery of dilute lidocaine to the L5 DRG can relieve L5 SNL-induced tactile...
Source: Pain - August 21, 2019 Category: Anesthesiology Tags: Research Paper Source Type: research

Can self-reported pain characteristics and bedside test be used for the assessment of pain mechanisms? An analysis of results of neuropathic pain questionnaires and quantitative sensory testing
Hyperalgesia and allodynia are frequent in neuropathic pain. Some pain questionnaires such as the Leeds Assessment of Neuropathic Symptoms and Signs (LANSS) and the Neuropathic Pain Scale (NPS) include self-assessment or bedside testing of hyperalgesia/allodynia. The aim of this study was to determine to what extent LANSS and NPS data are congruent with findings on quantitative sensory testing (QST). Self-reported presence of dynamic mechanical allodynia (DMA) and descriptors of hot, cold, or deep ongoing pain (the NPS and LANSS) as well as bedside findings of mechanical allodynia (LANSS) were compared with signs of DMA an...
Source: Pain - August 21, 2019 Category: Anesthesiology Tags: Research Paper Source Type: research

Opioid use, pain intensity, age, and sleep architecture in patients with fibromyalgia and insomnia
This study assessed associations between opioid use/dosage and polysomnographically assessed sleep in patients with fibromyalgia and insomnia (FMI) and examined moderating effects of age and pain. Participants (N = 193, Mage = 51.7, SD = 11.8, range = 18-77) with FMI completed ambulatory polysomnography and 14 daily diaries. Multiple regression determined whether commonly prescribed oral opioid use or dosage (among users) independently predicted or interacted with age/pain intensity to predict sleep, controlling for sleep medication use and apnea hypopnea index. Opioid use predicted greater %stage 2 and lower %slow-wave sl...
Source: Pain - August 21, 2019 Category: Anesthesiology Tags: Research Paper Source Type: research

Brain mechanisms of social touch-induced analgesia in females
In this study, women (N = 30) experienced thermal pain while holding their romantic partner's hand or an inert device. Social touch reduced pain and attenuated functional magnetic resonance imaging activity in the Neurologic Pain Signature (NPS)—a multivariate brain pattern sensitive and specific to somatic pain—and increased connectivity between the NPS and both somatosensory and “default mode” regions. Brain correlates of touch-induced analgesia included reduced pain-related activation in (1) regions targeted by primary nociceptive afferents (eg, posterior insula, and anterior cingulate cortex); a...
Source: Pain - August 21, 2019 Category: Anesthesiology Tags: Research Paper Source Type: research

Acute alcohol effects on conditioned pain modulation, but not temporal summation of pain
Although pain reduction after alcohol administration has repeatedly been demonstrated, alcohol effects on advanced and clinically relevant dynamic pain paradigms are still unknown. As such, temporal summation of pain (TSP) and conditioned pain modulation (CPM) indicate mechanisms of endogenous pain modulation and involve certain neurotransmitter systems crucially influenced by alcohol. Our study is the first to investigate acute alcohol effects on TSP and CPM. We investigated 39 healthy subjects in a placebo-controlled within-subject design and targeted alcohol levels of 0.06% (dose 1) and 0.08% (dose 2). Pain threshold, T...
Source: Pain - August 21, 2019 Category: Anesthesiology Tags: Research Paper Source Type: research

Cathepsin E in neutrophils contributes to the generation of neuropathic pain in experimental autoimmune encephalomyelitis
Pain is a frequent and disabling symptom in patients with multiple sclerosis (MS); however, the underlying mechanisms of MS-related pain are not fully understood. Here, we demonstrated that cathepsin E (CatE) in neutrophils contributes to the generation of mechanical allodynia in experimental autoimmune encephalomyelitis, an animal model of MS. We showed that CatE-deficient (CatE−/−) mice were highly resistant to myelin oligodendrocyte glycoprotein (MOG35-55)-induced mechanical allodynia. After MOG35-55 immunization, neutrophils immediately accumulated in the dorsal root ganglion (DRG). Adoptive transfer of MOG...
Source: Pain - August 21, 2019 Category: Anesthesiology Tags: Research Paper Source Type: research

Females have greater susceptibility to develop ongoing pain and central sensitization in a rat model of temporomandibular joint pain
Temporomandibular joint osteoarthritis (TMJOA) is a prevalent source of temporomandibular joint disorder (TMD). Women are more commonly diagnosed with TMD and are more likely to seek care at tertiary orofacial pain clinics. Limited knowledge regarding mechanisms underlying temporomandibular joint (TMJ) pain impairs development of improved pain management strategies. In a rat model of unilateral TMJOA, monosodium iodoacetate (MIA) produces joint pathology in a concentration-dependent manner. Unilateral MIA produces alterations in meal patterns in males and females without altering overnight time spent eating or weight acros...
Source: Pain - August 21, 2019 Category: Anesthesiology Tags: Research Paper Source Type: research

Brain moderators supporting the relationship between depressive mood and pain
Pain and depressive mood commonly exhibit a comorbid relationship. Yet, the brain mechanisms that moderate the relationship between dysphoric mood and pain remain unknown. An exploratory analysis of functional magnetic resonance imaging, behavioral, and psychophysical data was collected from a previous study in 76 healthy, nondepressed, and pain-free individuals. Participants completed the Beck Depression Inventory-II (BDI), a measure of negative mood/depressive symptomology, and provided pain intensity and pain unpleasantness ratings in response to noxious heat (49°C) during perfusion-based, arterial spin–labele...
Source: Pain - August 21, 2019 Category: Anesthesiology Tags: Research Paper Source Type: research

Sex differences in the temporal development of pronociceptive immune responses in the tibia fracture mouse model
Previously, distinct sex differences were observed in the pronociceptive role of spinal immune cells in neuropathic and inflammatory mouse pain models. Both peripheral and central innate and adaptive immune changes contribute to sensitization in the tibia fracture rodent model of complex regional pain syndrome, and the current study evaluated sex differences in the development of pronociceptive immune responses after fracture. At 4 and 7 weeks after fracture, the analgesic effects of a microglia inhibitor were tested in male and female mice, and polymerase chain reaction was used to measure inflammatory mediator expression...
Source: Pain - August 21, 2019 Category: Anesthesiology Tags: Research Paper Source Type: research

Reduced excitatory neurotransmitter levels in anterior insulae are associated with abdominal pain in irritable bowel syndrome
Irritable bowel syndrome (IBS) is a visceral pain condition with psychological comorbidity. Brain imaging studies in IBS demonstrate altered function in anterior insula (aINS), a key hub for integration of interoceptive, affective, and cognitive processes. However, alterations in aINS excitatory and inhibitory neurotransmission as putative biochemical underpinnings of these functional changes remain elusive. Using quantitative magnetic resonance spectroscopy, we compared women with IBS and healthy women (healthy controls [HC]) with respect to aINS glutamate + glutamine (Glx) and γ-aminobutyric acid (GABA+) concentrat...
Source: Pain - August 21, 2019 Category: Anesthesiology Tags: Research Paper Source Type: research

Antibodies binding the head domain of P2X4 inhibit channel function and reverse neuropathic pain
P2X4 is a ligand-gated ion channel implicated in neuropathic pain. Drug discovery efforts targeting P2X4 have been unsuccessful largely because of the difficulty in engineering specificity and selectivity. Here, we describe for the first time the generation of a panel of diverse monoclonal antibodies (mAbs) to human and mouse P2X4, capable of both positive and negative modulation of channel function. The affinity-optimised anti-P2X4 mAb IgG#151-LO showed exquisite selectivity for human P2X4 and induced potent and complete block of P2X4 currents. Site-directed mutagenesis of P2X4 revealed the head domain as a key interactio...
Source: Pain - August 21, 2019 Category: Anesthesiology Tags: Research Paper Source Type: research

High-threshold primary afferent supply of spinal lamina X neurons
The spinal gray matter region around the central canal, lamina X, is critically involved in somatosensory processing and visceral nociception. Although several classes of primary afferent fibers terminate or decussate in this area, little is known about organization and functional significance of the afferent supply of lamina X neurons. Using the hemisected ex vivo spinal cord preparation, we show that virtually all lamina X neurons receive primary afferent inputs, which are predominantly mediated by the high-threshold Aδ- fibers and C-fibers. In two-thirds of the neurons tested, the inputs were monosynaptic, implyin...
Source: Pain - August 21, 2019 Category: Anesthesiology Tags: Research Paper Source Type: research

Development and course of chronic widespread pain: the role of time and pain characteristics (the HUNT pain study)
Chronic widespread pain (CWP) is common and associated with loss of functioning and health. Subjects with chronic nonwidespread pain (CnWP) are at increased risk of developing CWP, but few studies have described the nature of the development over time. We followed a random sample of 3105 participants from the population-based HUNT 3 study with 5 annual measurements of pain over 4 years. Although 29% reported CWP on at least 1 occasion, only 7% reported it consistently on 4 or 5 occasions. The average annual cumulative incidence was 5%, and the recovery rate was 38%. In mutual adjusted analysis, the risk of developing CWP f...
Source: Pain - August 21, 2019 Category: Anesthesiology Tags: Research Paper Source Type: research

Cooling the skin for assessing small-fibre function
In this clinical and neurophysiological study using a novel cold stimulator, we aim at investigating whether cold-evoked potentials (CEPs) may prove to be a reliable diagnostic tool to assess trigeminal small-fibre function. Using a novel device consisting of micro-Peltier elements, we recorded CEPs after stimulating the supraorbital and perioral regions and the hand dorsum in 15 healthy participants and in 2 patients with exemplary facial neuropathic pain conditions. We measured peripheral conduction velocity at the upper arm and studied the brain generators using source analysis. In healthy participants and patients, we ...
Source: Pain - August 21, 2019 Category: Anesthesiology Tags: Research Paper Source Type: research

How are pain and traumatic stress symptoms related in acute whiplash–associated disorders? An investigation of the role of pain-related fear in a daily diary study
This study investigated the direction of the relationship between pain and traumatic stress and the role that pain-related fear plays, for patients with acute whiplash–associated disorder. Participants (n = 99) used an electronic diary to record hourly ratings of pain, traumatic stress, and fear of pain (FOP) symptoms over a day. Relationships between pain, traumatic stress, and pain-related fear symptoms were investigated through multilevel models including variables lagged by 1 hour. Traumatic stress was associated with previous pain, even after controlling for previous traumatic stress and current pain; current pa...
Source: Pain - August 21, 2019 Category: Anesthesiology Tags: Research Paper Source Type: research

Meta-analysis of the psychometric properties of the Pain Catastrophizing Scale and associations with participant characteristics
The aims of this study were to review the psychometric properties of the widely used Pain Catastrophizing Scale (PCS) using meta-analytic methods and to investigate the relationship between PCS scores and participant characteristics. A systematic search from 1995 found 229 experimental, quasi-experimental, and correlational studies that report PCS scores. Multivariate regression explored variables related to pain catastrophizing and participant demographics. Across studies, good internal reliability (α = 0.92, 95% confidence interval 0.91-0.93) and test–retest reliability scores (Spearman ρ = 0.88, 95% conf...
Source: Pain - August 21, 2019 Category: Anesthesiology Tags: Systematic Reviews and Meta-Analyses Source Type: research

Do chronic pain and comorbidities affect brain function in sickle cell patients? A systematic review of neuroimaging and treatment approaches
Sickle cell disease (SCD) is a medical condition in which chronic pain is common and negatively impacts psychosocial function and quality of life. Although the brain mechanisms underlying chronic pain are well studied in other painful conditions, the brain mechanisms underlying chronic pain and the associated psychosocial comorbidities are not well established in SCD. A growing literature demonstrates the effect of treatment of chronic pain, including pharmacological and nonpharmacological treatments, on brain function. The present systematic review aimed to (1) determine the effects of chronic pain and psychosocial comorb...
Source: Pain - August 21, 2019 Category: Anesthesiology Tags: Systematic Reviews and Meta-Analyses Source Type: research

Quantitative sensory testing and predicting outcomes for musculoskeletal pain, disability, and negative affect: a systematic review and meta-analysis
Hypersensitivity due to central pain mechanisms can influence recovery and lead to worse clinical outcomes, but the ability of quantitative sensory testing (QST), an index of sensitisation, to predict outcomes in chronic musculoskeletal disorders remains unclear. We systematically reviewed the evidence for ability of QST to predict pain, disability, and negative affect using searches of CENTRAL, MEDLINE, EMBASE, AMED, CINAHL, and PubMed databases up to April 2018. Title screening, data extraction, and methodological quality assessments were performed independently by 2 reviewers. Associations were reported between baseline...
Source: Pain - August 21, 2019 Category: Anesthesiology Tags: Systematic Reviews and Meta-Analyses Source Type: research

Virtual reality, music, and pain: developing the premise for an interdisciplinary approach to pain management
No abstract available (Source: Pain)
Source: Pain - August 21, 2019 Category: Anesthesiology Tags: Topical Review Source Type: research

New promising targets to control neuropathic pain
No abstract available (Source: Pain)
Source: Pain - August 21, 2019 Category: Anesthesiology Tags: Commentary Source Type: research

Mirogabalin for the management of postherpetic neuralgia: a randomized, double-blind, placebo-controlled phase 3 study in Asian patients: Erratum.
No abstract available (Source: Pain)
Source: Pain - July 25, 2019 Category: Anesthesiology Tags: Erratum Source Type: research

Reply to Tapia et al.
No abstract available (Source: Pain)
Source: Pain - July 25, 2019 Category: Anesthesiology Tags: Correspondence Source Type: research

Spinal cord stimulation for failed back surgery: all that glitters is not gold
No abstract available (Source: Pain)
Source: Pain - July 25, 2019 Category: Anesthesiology Tags: Correspondence Source Type: research

Reply to Dildine and Atlas
No abstract available (Source: Pain)
Source: Pain - July 25, 2019 Category: Anesthesiology Tags: Correspondence Source Type: research

The need for diversity in research on facial expressions of pain
No abstract available (Source: Pain)
Source: Pain - July 25, 2019 Category: Anesthesiology Tags: Correspondence Source Type: research

Parallels between lumbosacral radiculopathy and complex regional pain syndrome: α: 1: -adrenoceptor upregulation, reduced dermal nerve fibre density, and hemisensory disturbances in postsurgical sciatica
Residual lower-limb pain after low back surgery (postsurgical sciatica) and complex regional pain syndrome (CRPS) involving a lower limb are separate conditions but may share some mechanisms (eg, tissue inflammation, neuroimmune disturbances, and central neuroplasticity). As adrenergically evoked pain contributes, in part, to CRPS, whether an adrenergic mechanism also contributes to postsurgical sciatica was investigated in this study. Immunohistochemistry was used to identify α1-adrenoceptors (α1-AR) on nerve fibres and other targets in the affected and contralateral skin of 25 patients with postsurgical sciat...
Source: Pain - July 25, 2019 Category: Anesthesiology Tags: Research Paper Source Type: research

Endogenous pain modulation in children with functional abdominal pain disorders
Functional abdominal pain disorders (FAPDs) are common among young individuals. To date, relatively little is known regarding the function of the endogenous analgesic mechanisms in this vulnerable group. Therefore, this case–control study aimed to compare conditioned pain modulation (CPM), pressure algometry, and psychosocial variables in 39 young children (aged 6-12 years) with FAPD and 36 age- and sex-matched pain-free controls. Pressure algometry was used to assess pressure pain thresholds (PPTs) at both symptomatic (umbilicus) as remote (trapezius and tibia) test sites. Conditioned pain modulation was recorded as...
Source: Pain - July 25, 2019 Category: Anesthesiology Tags: Research Paper Source Type: research

Interleukin 6 decreases nociceptor expression of the potassium channel KV1.4 in a rat model of hand–arm vibration syndrome
Chronic muscle pain is a prominent symptom of the hand–arm vibration syndrome (HAVS), an occupational disease induced by exposure to vibrating power tools, but the underlying mechanism remains unknown. We evaluated the hypothesis that vibration induces an interleukin 6 (IL-6)-mediated downregulation of the potassium voltage-gated channel subfamily A member 4 (KV1.4) in nociceptors leading to muscle pain. Adult male rats were submitted to a protocol of mechanical vibration of the right hind limb. Twenty-four hours after vibration, muscle hyperalgesia was observed, concomitant to increased levels of IL-6 in the gastroc...
Source: Pain - July 25, 2019 Category: Anesthesiology Tags: Research Paper Source Type: research

The role of narrative in the development of children's pain memories: influences of father– and mother–child reminiscing on children's recall of pain
This study examined the role of parent–child reminiscing about a recent painful surgery in young children's pain memory development. Participants included 112 children (Mage = 5.3 years; 60% boys) who underwent a tonsillectomy and one of their parents (34% fathers). Pain was assessed in hospital and during the recovery phase at home. Two weeks after surgery, parents and children attended a laboratory visit to participate in a structured narrative elicitation task wherein they reminisced about the surgery. Four weeks after surgery, children completed an established pain memory interview using the same previously admin...
Source: Pain - July 25, 2019 Category: Anesthesiology Tags: Research Paper Source Type: research

Pain-related functional interference in patients with chronic neuropathic postsurgical pain: an analysis of registry data
Although chronic postsurgical pain (CPSP) is a major health care problem, pain-related functional interference has rarely been investigated. Using the PAIN OUT registry, we evaluated patients' pain-related outcomes on the first postoperative day, and their pain-related interference with daily living (Brief Pain Inventory) and neuropathic symptoms (DN4: douleur neuropathique en 4 questions) at 6 months after surgery. Endpoints were pain interference total scores (PITS) and their association with pain and DN4 scores. Furthermore, possible risk factors associated with impaired function at M6 were analyzed by ordinal regressio...
Source: Pain - July 25, 2019 Category: Anesthesiology Tags: Research Paper Source Type: research

Antihyperalgesic effects of Meteorin in the rat chronic constriction injury model: a replication study
Data from preclinical research have been suggested to suffer from a lack of inherent reproducibility across laboratories. The goal of our study was to replicate findings from a previous report that demonstrated positive effects of Meteorin, a novel neurotrophic factor, in a rat model of neuropathic pain induced by chronic constriction injury (CCI). Notably, 5 to 6 intermittent subcutaneous (s.c.) injections of Meteorin had been reported to produce reversal of mechanical allodynia/thermal hyperalgesia after injury, wherein maximum efficacy of Meteorin was reached slowly and outlasted the elimination of the compound from the...
Source: Pain - July 25, 2019 Category: Anesthesiology Tags: Research Paper Source Type: research

Somatosensory predictors of response to pregabalin in painful chemotherapy-induced peripheral neuropathy: a randomized, placebo-controlled, crossover study
Painful chemotherapy-induced peripheral neuropathy (CIPN) is a debilitating and treatment-resistant sequela of many chemotherapeutic medications. Ligands of α2δ subunits of voltage-gated Ca2+ channels, such as pregabalin, have shown efficacy in reducing mechanical sensitivity in animal models of neuropathic pain. In addition, some data suggest that pregabalin may be more efficacious in relieving neuropathic pain in subjects with increased sensitivity to pinprick. We hypothesized that greater mechanical sensitivity, as quantified by decreased mechanical pain threshold at the feet, would be predictive of a greate...
Source: Pain - July 25, 2019 Category: Anesthesiology Tags: Research Paper Source Type: research

OPRM1 rs1799971, COMT rs4680, and FAAH rs324420 genes interact with placebo procedures to induce hypoalgesia
In this study, we expanded on previous findings related to the 3 SNPs in the opioid receptor mu subunit (OPRM1 rs1799971), catechol-O-methyltransferase (COMT rs4680), and fatty acid amide hydrolase (FAAH rs324420) genes associated with placebo hypoalgesia and tested the effect of a 3-way interaction on placebo hypoalgesia. Using 2 well-established placebo procedures (verbal suggestion and learning paradigm), we induced significant placebo hypoalgesic effects in 160 healthy participants. We found that individuals with OPRM1 AA combined with FAAH Pro/Pro and those carrying COMT met/met together with FAAH Pro/Pro showed signi...
Source: Pain - July 25, 2019 Category: Anesthesiology Tags: Research Paper Source Type: research

The relationship between regional pain with or without neuropathic symptoms and chronic widespread pain
This study was performed to test whether the risk of developing chronic widespread pain (CWP) in those with regional pain was augmented in those with symptoms of neuropathic pain (NP). Persons free of CWP completed the Douleur Neuropathique 4 (scores ≥3 indicating NP); demographics; Hospital Anxiety and Depression scale; Pittsburgh Sleep Quality Index; and pain medications. Participants were classified as having no pain, regional pain with no symptoms of NP ( JOURNAL/jpain/04.02/00006396-201908000-00014/math_14MM1/v/2019-07-21T190841Z/r/image-tiff ), or regional pain with symptoms of NP (NP). At the 12-month follow-up...
Source: Pain - July 25, 2019 Category: Anesthesiology Tags: Research Paper Source Type: research

NOD-like receptor protein 3 inflammasome drives postoperative mechanical pain in a sex-dependent manner
Postoperative pain management continues to be suboptimal because of the lack of effective nonopioid therapies and absence of understanding of sex-driven differences. Here, we asked how the NLRP3 inflammasome contributes to postoperative pain. Inflammasomes are mediators of the innate immune system that are responsible for activation and secretion of IL-1β upon stimulation by specific molecular signals. Peripheral IL-1β is known to contribute to the mechanical sensitization induced by surgical incision. However, it is not known which inflammasome mediates the IL-1β release after surgical incision. Among the 9...
Source: Pain - July 25, 2019 Category: Anesthesiology Tags: Research Paper Source Type: research

Progesterone relates to enhanced incisional acute pain and pinprick hyperalgesia in the luteal phase of female volunteers
The role of sex hormones on postsurgical pain perception is basically unclear. Here, we studied the role of endogenous gonadal hormones for pain and hyperalgesia in human volunteers after experimental incision. A 4-mm incision was made in the volar forearm of 15 female volunteers both in the follicular and the luteal phase (random block design). Somatosensory profiles were assessed at baseline and 1 to 72 hours after incision by quantitative sensory testing, compared between both cycle phases, and related to individual plasma levels of gonadal hormones. Sensory testing at baseline revealed significantly lower pain threshol...
Source: Pain - July 25, 2019 Category: Anesthesiology Tags: Research Paper Source Type: research

Antiallodynic effects of the selective NaV1.7 inhibitor Pn3a in a mouse model of acute postsurgical pain: evidence for analgesic synergy with opioids and baclofen
Pain is the leading cause of disability in the developed world but remains a poorly treated condition. Specifically, postsurgical pain continues to be a frequent and undermanaged condition. Here, we investigate the analgesic potential of pharmacological NaV1.7 inhibition in a mouse model of acute postsurgical pain, based on incision of the plantar skin and underlying muscle of the hind paw. We demonstrate that local and systemic treatment with the selective NaV1.7 inhibitor μ-theraphotoxin-Pn3a is effectively antiallodynic in this model and completely reverses mechanical hypersensitivity in the absence of motor adverse ...
Source: Pain - July 25, 2019 Category: Anesthesiology Tags: Research Paper Source Type: research

An NPY Y1 receptor antagonist unmasks latent sensitization and reveals the contribution of protein kinase A and Epac to chronic inflammatory pain
Peripheral inflammation produces a long-lasting latent sensitization of spinal nociceptive neurons, that is, masked by tonic inhibitory controls. We explored mechanisms of latent sensitization with an established four-step approach: (1) induction of inflammation; (2) allow pain hypersensitivity to resolve; (3) interrogate latent sensitization with a channel blocker, mutant mouse, or receptor antagonist; and (4) disrupt compensatory inhibition with a receptor antagonist so as to reinstate pain hypersensitivity. We found that the neuropeptide Y Y1 receptor antagonist BIBO3304 reinstated pain hypersensitivity, indicative of a...
Source: Pain - July 25, 2019 Category: Anesthesiology Tags: Research Paper Source Type: research

Genetic mapping in Diversity Outbred mice identifies a Trpa1 variant influencing late-phase formalin response
This study demonstrates the utility of advanced, high-precision genetic mapping populations in resolving specific molecular mechanisms of variation in pain sensitivity. (Source: Pain)
Source: Pain - July 25, 2019 Category: Anesthesiology Tags: Research Paper Source Type: research

Remembering the pain of surgery 1 year later: a longitudinal examination of anxiety in children's pain memory development
Children who develop greater negatively-biased recall of pain (ie, recalled pain is higher than the initial pain report) following surgery are at risk for developing chronic pain; therefore, identifying risk factors for the development of biased pain memories is important. Higher anxiety has been implicated in the development of greater negatively-biased recall of pain; however, studies have not examined anxiety at multiple time points before and after a surgery and its relationship to children's postsurgical pain memories after 1 year. This prospective study examined a cohort of 237 children and adolescents undergoing maj...
Source: Pain - July 25, 2019 Category: Anesthesiology Tags: Research Paper Source Type: research

Cortisol affects pain sensitivity and pain-related emotional learning in experimental visceral but not somatic pain: a randomized controlled study in healthy men and women
Despite growing interest in the role of stress mediators in pain chronicity, the effects of the stress hormone cortisol on acute pain remain incompletely understood. In a randomized, double-blind, placebo-controlled study with N = 100 healthy volunteers, we tested the effects of oral hydrocortisone (20 mg) in 2 widely used pain models for the visceral and somatic modality. Salivary cortisol was increased in the hydrocortisone group (time × group: P (Source: Pain)
Source: Pain - July 25, 2019 Category: Anesthesiology Tags: Research Paper Source Type: research

Efficacy of a transdiagnostic emotion–focused exposure treatment for chronic pain patients with comorbid anxiety and depression: a randomized controlled trial
This study addresses the efficacy of a transdiagnostic emotion–focused exposure treatment (“hybrid”) for chronic pain patients with comorbid emotional problems. Adults (n = 115) with chronic musculoskeletal pain and functional and emotional problems were included in a 2-centre, parallel randomized controlled, open-label trial comparing this treatment to an active control condition receiving a guided Internet-delivered pain management treatment based on CBT principles (iCBT). The hybrid treatment (n = 58, 10-16 sessions) integrates exposure in vivo for chronic pain based on the fear-avoidance model with an...
Source: Pain - July 25, 2019 Category: Anesthesiology Tags: Research Paper Source Type: research

Pharmacological interventions for chronic pain in children: an overview of systematic reviews
We know little about the safety or efficacy of pharmacological medicines for children and adolescents with chronic pain, despite their common use. Our aim was to conduct an overview review of systematic reviews of pharmacological interventions that purport to reduce pain in children with chronic noncancer pain (CNCP) or chronic cancer-related pain (CCRP). We searched the Cochrane Database of Systematic Reviews, Medline, EMBASE, and DARE for systematic reviews from inception to March 2018. We conducted reference and citation searches of included reviews. We included children (0-18 years of age) with CNCP or CCRP. We extract...
Source: Pain - July 25, 2019 Category: Anesthesiology Tags: Systematic Review and Meta-Analysis Source Type: research