Does the word “placebo” evoke a placebo response?
No abstract available (Source: Pain)
Source: Pain - October 1, 2018 Category: Anesthesiology Tags: Topical Review Source Type: research

Chronic pain in survivors of childhood cancer: a developmental model of pain across the cancer trajectory
No abstract available (Source: Pain)
Source: Pain - October 1, 2018 Category: Anesthesiology Tags: Topical Review Source Type: research

Targeting toll-like receptor-4 (TLR4)—an emerging therapeutic target for persistent pain states
Toll-like receptors (TLRs) are a family of pattern recognition receptors that initiate signaling in innate and adaptive immune pathways. The highly conserved family of transmembrane proteins comprises an extracellular domain that recognizes exogenous and endogenous danger molecules and an ectodomain that activates downstream pathways in response. Recent studies suggest that continuous activation or dysregulation of TLR signaling may contribute to chronic disease states. The receptor is located not only on inflammatory cells (meningeal and peripheral macrophages) but on neuraxial glia (microglia and astrocytes), Schwann cel...
Source: Pain - October 1, 2018 Category: Anesthesiology Tags: Comprehensive Review Source Type: research

Systematic reviews with meta-analysis on cannabis-based medicines for chronic pain: a methodological and political minefield
No abstract available (Source: Pain)
Source: Pain - October 1, 2018 Category: Anesthesiology Tags: Commentary Source Type: research

Responses to the sham treatment vs expectancy effects
No abstract available (Source: Pain)
Source: Pain - October 1, 2018 Category: Anesthesiology Tags: Commentary Source Type: research

Hyperpolarization-activated cyclic nucleotide–gated channels contribute to spontaneous activity in L4 C-fiber nociceptors, but not Aβ-non-nociceptors, after axotomy of L5-spinal nerve in the rat in vivo: Erratum.
No abstract available (Source: Pain)
Source: Pain - August 23, 2018 Category: Anesthesiology Tags: Erratum Source Type: research

Sensory phenotype and risk factors for painful diabetic neuropathy: a cross-sectional observational study Erratum.
No abstract available (Source: Pain)
Source: Pain - August 23, 2018 Category: Anesthesiology Tags: Erratum Source Type: research

“From ear to trunk”—magnetic resonance imaging reveals referral of pain
We present the case of a 69-year-old female patient with postherpetic neuralgia in dermatome Th2/3 who reported that touching the ipsilateral earlap (dermatome C2) would enhance pain and dynamic mechanical allodynia in the affected Th2/3-dermatome. The aim was to investigate possible underlying mechanisms of this phenomenon using the capsaicin experimental pain sensitization model, quantitative sensory testing, and functional spinal and supraspinal magnetic resonance imaging. The presented study provides evidence that a referral of pain from the ear to the trunk is possible. We discuss whether the observed phenomenon in co...
Source: Pain - August 23, 2018 Category: Anesthesiology Tags: Clinical Note Source Type: research

Selective deficiencies in descending inhibitory modulation in neuropathic rats: implications for enhancing noradrenergic tone
We examined the extent to which the descending noradrenergic system is tonically active, how control of spinal neuronal excitability is integrated into thalamic relays within sensory-discriminative projection pathways, and how this inhibitory control is altered after nerve injury. In vivo electrophysiology was performed in anaesthetised spinal nerve–ligated (SNL) and sham-operated rats to record from wide dynamic range neurones in the ventral posterolateral thalamus (VPL). In sham rats, spinal block of α2-adrenoceptors with atipamezole resulted in enhanced stimulus-evoked and spontaneous firing in the VPL, and ...
Source: Pain - August 23, 2018 Category: Anesthesiology Tags: Research Paper Source Type: research

Pain sensitization associated with nonresponse after physiotherapy in people with knee osteoarthritis
This study aimed to prospectively investigate the association between features of pain sensitization and clinical outcome (nonresponse) after guideline-based physiotherapy in people with knee OA. Participants (n = 156) with moderate/severe knee OA were recruited from secondary care. All participants completed self-administered questionnaires and underwent quantitative sensory testing at baseline, thereby establishing subjective and objective measures of pain sensitization. Participants (n = 134) were later classified after a physiotherapy intervention, using treatment responder criteria (responder/nonresponder). Quantitati...
Source: Pain - August 23, 2018 Category: Anesthesiology Tags: Research Paper Source Type: research

Sensory profiles and skin innervation of patients with painful and painless neuropathies
We assessed pain characteristics and sensory profiles of a large and extensively phenotyped cohort of patients with polyneuropathies (PNPs) and small fiber neuropathy (SFN) using quantitative sensory testing (QST). Our aim was to detect potentially discriminative QST profiles of patient subgroups determined by pain, etiology, or skin innervation. We prospectively recruited 350 patients with painful and painless PNPs and with SFN at 1 neuromuscular center. After neurological work-up, patients underwent QST at the dorsal foot and 5-mm skin punch biopsy at the lower leg and upper thigh for intraepidermal nerve fiber counts. A...
Source: Pain - August 23, 2018 Category: Anesthesiology Tags: Research Paper Source Type: research

Chronic neuropathic pain reduces opioid receptor availability with associated anhedonia in rat
The opioid system plays a critical role in both the experience and management of pain. Although acute activation of the opioid system can lead to pain relief, the effects of chronic pain on the opioid system remain opaque. Cross-sectional positron emission tomography (PET) studies show reduced availability of brain opioid receptors in patients with chronic pain but are unable to (1) determine whether these changes are due to the chronic pain itself or due to preexisting or medication-induced differences in the endogenous opioid system, and (2) identify the neurobiological substrate of reduced opioid receptor availability. ...
Source: Pain - August 23, 2018 Category: Anesthesiology Tags: Research Paper Source Type: research

Delayed onset of persistent discogenic axial and radiating pain after a single-level lumbar intervertebral disc injury in mice
Low back pain (LBP) is associated with both axial discomfort and radiating leg pain. Although intervertebral discs are suspected as the source of pain in some individuals, the relationship between disc degeneration and back pain remains controversial. The goals of this study were to investigate the long-term impact of L4/L5 disc puncture on disc degeneration and the subsequent emergence, persistence, and underlying mechanisms of axial and radiating LBP in mice. L4 to L5 discs were punctured on the ventral aspect with a 30 gauge needle in 3-month old female CD1 mice, and the development of behavioral signs of axial discomfo...
Source: Pain - August 23, 2018 Category: Anesthesiology Tags: Research Paper Source Type: research

Effects of internet-based pain coping skills training before home exercise for individuals with hip osteoarthritis (HOPE trial): a randomised controlled trial
This assessor-, therapist-, and participant-blinded randomised controlled trial evaluated the effects of an automated internet-based pain coping skills training (PCST) program before home exercise for people with clinically diagnosed hip osteoarthritis. One hundred forty-four people were randomised to either the PCST group or the comparator group. In the first 8 weeks, the PCST group received online education and PCST, whereas the comparison group received online education only. From weeks 8 to 24, both groups visited a physiotherapist 5 times for home exercise prescription. Assessments were performed at baseline, 8, 24, a...
Source: Pain - August 23, 2018 Category: Anesthesiology Tags: Research Paper Source Type: research

Hemisensory disturbances in patients with complex regional pain syndrome
Sensory disturbances often spread beyond the site of injury in complex regional pain syndrome (CRPS) but whether this applies equally to CRPS I and II, or changes across the course of the disease, is unknown. Establishing this is important, because different symptom profiles in CRPS I and II, or in acute vs chronic CRPS, might infer different pathophysiology and treatment approaches. To explore these questions, sensory disturbances were assessed in the limbs and forehead of 71 patients with CRPS I and 33 patients with CRPS II. Pain had persisted up to 12 months in 32 patients, for 13 to 36 months in 29 patients, and for lo...
Source: Pain - August 23, 2018 Category: Anesthesiology Tags: Research Paper Source Type: research

Peripherally restricted cannabinoid 1 receptor agonist as a novel analgesic in cancer-induced bone pain
Many malignant cancers, including breast cancer, have a propensity to invade bones, leading to excruciating bone pain. Opioids are the primary analgesics used to alleviate this cancer-induced bone pain (CIBP) but are associated with numerous severe side effects, including enhanced bone degradation, which significantly impairs patients' quality of life. By contrast, agonists activating only peripheral CB1 receptors (CB1Rs) have been shown to effectively alleviate multiple chronic pain conditions with limited side effects, yet no studies have evaluated their role(s) in CIBP. Here, we demonstrate for the first time that a per...
Source: Pain - August 23, 2018 Category: Anesthesiology Tags: Research Paper Source Type: research

Involvement of the VGF-derived peptide TLQP-62 in nerve injury–induced hypersensitivity and spinal neuroplasticity
Neuroplasticity in the dorsal horn after peripheral nerve damage contributes critically to the establishment of chronic pain. The neurosecretory protein VGF (nonacronymic) is rapidly and robustly upregulated after nerve injury, and therefore, peptides generated from it are positioned to serve as signals for peripheral damage. The goal of this project was to understand the spinal modulatory effects of the C-terminal VGF-derived peptide TLQP-62 at the cellular level and gain insight into the function of the peptide in the development of neuropathic pain. In a rodent model of neuropathic pain, we demonstrate that endogenous l...
Source: Pain - August 23, 2018 Category: Anesthesiology Tags: Research Paper Source Type: research

Efficacy of hypnosis on pain, wound-healing, anxiety, and stress in children with acute burn injuries: a randomized controlled trial
No randomized controlled trial has investigated the efficacy of hypnosis for reducing pain and improving wound-healing in children with burns. This randomized controlled trial aimed to investigate whether hypnosis decreases pain, anxiety, and stress and accelerates wound-healing in children undergoing burn wound procedures. Children (4-16 years) with acute burns presenting for their first dressing change were randomly assigned to a Hypnosis Group who received hypnosis plus standard care or a Standard Care Group who received standard pharmacological and nonpharmacological intervention. Repeated measures of pain intensity, a...
Source: Pain - August 23, 2018 Category: Anesthesiology Tags: Research Paper Source Type: research

Chronic stress-associated visceral hyperalgesia correlates with severity of intestinal barrier dysfunction
In humans, chronic psychological stress is associated with increased intestinal paracellular permeability and visceral hyperalgesia, which is recapitulated in the chronic intermittent water avoidance stress (WAS) rat model. However, it is unknown whether enhanced visceral pain and permeability are intrinsically linked and correlate. Treatment of rats with lubiprostone during WAS significantly reduced WAS-induced changes in intestinal epithelial paracellular permeability and visceral hyperalgesia in a subpopulation of rats. Lubiprostone also prevented WAS-induced decreases in the epithelial tight junction protein, occludin ...
Source: Pain - August 23, 2018 Category: Anesthesiology Tags: Research Paper Source Type: research

Multivariate machine learning distinguishes cross-network dynamic functional connectivity patterns in state and trait neuropathic pain
Communication within the brain is dynamic. Chronic pain can also be dynamic, with varying intensities experienced over time. Little is known of how brain dynamics are disrupted in chronic pain, or relates to patients' pain assessed at various timescales (eg, short-term state vs long-term trait). Patients experience pain “traits” indicative of their general condition, but also pain “states” that vary day to day. Here, we used network-based multivariate machine learning to determine how patterns in dynamic and static brain communication are related to different characteristics and timescales of chroni...
Source: Pain - August 23, 2018 Category: Anesthesiology Tags: Research Paper Source Type: research

Microglial P2X4R-evoked pain hypersensitivity is sexually dimorphic in rats
Microglia–neuron signalling in the spinal cord is a key mediator of mechanical allodynia caused by peripheral nerve injury. We recently reported sex differences in microglia in pain signalling in mice: spinal mechanisms underlying nerve injury–induced allodynia are microglial dependent in male but not female mice. Whether this sex difference in pain hypersensitivity mechanisms is conserved in other species is unknown. Here, we show that in rats, the spinal mechanisms of nerve injury–induced hypersensitivity in males differ from those in females, with microglial P2X4 receptors (P2X4Rs) being a key point of...
Source: Pain - August 23, 2018 Category: Anesthesiology Tags: Research Paper Source Type: research

A randomised, placebo-controlled clinical trial with the α2/3/5 subunit selective GABAA positive allosteric modulator PF-06372865 in patients with chronic low back pain
The effect of PF-06372865, a subtype-selective positive allosteric modulator of the γ-aminobutyric acid type A (GABAA) receptor, on chronic low back pain was investigated in a randomised, placebo- and active-controlled phase 2 clinical trial. The parallel treatment group trial consisted of a 1-week single-blind placebo run in the phase, followed by 4-week double-blind treatment. Patients were randomised to receive either PF-06372865, naproxen, or placebo twice a day for 4 weeks. The primary end point was the numerical rating score of low back pain intensity after 4 weeks of active treatment. Secondary end points incl...
Source: Pain - August 23, 2018 Category: Anesthesiology Tags: Research Paper Source Type: research

High-fat diet exacerbates postoperative pain and inflammation in a sex-dependent manner
In this study, effects of diet and obesity were examined in the paw incision model, a preclinical model of postoperative pain. Long–Evans rats were fed high-fat diet (40% calories from butter fat) or low-fat normal chow. Male rats fed high-fat diet starting 6 weeks before incision (a diet previously shown to induce markers of obesity) had prolonged mechanical hypersensitivity and an overall increase in spontaneous pain in response to paw incision, compared with normal chow controls. Diet effects in females were minor. Removing high-fat diet for 2 weeks before incision reversed the diet effects on pain behaviors, alth...
Source: Pain - August 23, 2018 Category: Anesthesiology Tags: Research Paper Source Type: research

NALCN channels enhance the intrinsic excitability of spinal projection neurons
Spinal projection neurons convey nociceptive signals to multiple brain regions including the parabrachial (PB) nucleus, which contributes to the emotional valence of pain perception. Despite the clear importance of projection neurons to pain processing, our understanding of the factors that shape their intrinsic membrane excitability remains limited. Here, we investigate a potential role for the Na+ leak channel NALCN in regulating the activity of spino-PB neurons in the developing rodent. Pharmacological reduction of NALCN current (INALCN), or the genetic deletion of NALCN channels, significantly reduced the intrinsic exc...
Source: Pain - August 23, 2018 Category: Anesthesiology Tags: Research Paper Source Type: research

A bifunctional-biased mu-opioid agonist–neuropeptide FF receptor antagonist as analgesic with improved acute and chronic side effects
Opioid analgesics, such as morphine, oxycodone, and fentanyl, are the cornerstones for treating moderate to severe pain. However, on chronic administration, their efficiency is limited by prominent side effects such as analgesic tolerance and dependence liability. Neuropeptide FF (NPFF) and its receptors (NPFF1R and NPFF2R) are recognized as an important pronociceptive system involved in opioid-induced hyperalgesia and analgesic tolerance. In this article, we report the design of multitarget peptidomimetic compounds that show high-affinity binding to the mu-opioid receptor (MOPr) and NPFFRs. In vitro characterization of th...
Source: Pain - August 23, 2018 Category: Anesthesiology Tags: Research Paper Source Type: research

Perioperative lidocaine infusions for the prevention of chronic postsurgical pain: a systematic review and meta-analysis of efficacy and safety
Chronic postsurgical pain (CPSP) occurs in 12% of surgical populations and is a high priority for perioperative research. Systemic lidocaine may modulate several of the pathophysiological processes linked to CPSP. This systematic review aims to identify and synthesize the evidence linking lidocaine infusions and CPSP. The authors conducted a systematic literature search of the major medical databases from inception until October 2017. Trials that randomized adults without baseline pain to perioperative lidocaine infusion or placebo were included if they reported on CPSP. The primary outcome was the presence of procedure-re...
Source: Pain - August 23, 2018 Category: Anesthesiology Tags: Systematic Review and Meta-Analysis Source Type: research

Pain as a threat to the social self: a motivational account
No abstract available (Source: Pain)
Source: Pain - August 23, 2018 Category: Anesthesiology Tags: Topical Review Source Type: research

Reproducible and replicable pain research: a critical review
No abstract available (Source: Pain)
Source: Pain - August 23, 2018 Category: Anesthesiology Tags: Topical Review Source Type: research

Perspective: update on pain education
No abstract available (Source: Pain)
Source: Pain - August 23, 2018 Category: Anesthesiology Tags: Perspectives Source Type: research

Chronic pain and opioid receptor availability: disentangling the molecular contributions and the “chicken or the egg” dilemma
No abstract available (Source: Pain)
Source: Pain - August 23, 2018 Category: Anesthesiology Tags: Commentary Source Type: research

Lidocaine infusions and preventative analgesia: can the answer to our prayers be hiding right under our noses?
No abstract available (Source: Pain)
Source: Pain - August 23, 2018 Category: Anesthesiology Tags: Commentary Source Type: research

Spinal GABAA receptors for pain control—lost in translation?
No abstract available (Source: Pain)
Source: Pain - August 23, 2018 Category: Anesthesiology Tags: Commentary Source Type: research

Interleukin-6 trans-signaling and pathological low back pain in patients with Paget disease of bone
The interleukin (IL)-6 biological system plays a key role in the pathogenesis of Paget disease (PD) of bone and pathological bone pain. Bone pain, particularly in the lower back region, is the most frequent symptom in patients with PD. This case–control study aimed to evaluate the relationship between the IL-6 system and low back pain (LBP) in patients with PD. We evaluated 85 patients with PD, with the disease localized in the lumbar spine, pelvis, and/or sacrum, and classified them based on the presence or absence of LBP, before and after aminobisphosphonate treatment. We also examined 32 healthy controls without L...
Source: Pain - July 26, 2018 Category: Anesthesiology Tags: Research Paper Source Type: research

Chemokine (c-c motif) receptor 2 mediates mechanical and cold hypersensitivity in sickle cell disease mice
Approximately one-third of individuals with sickle cell disease (SCD) develop chronic pain. This debilitating pain is inadequately treated because the underlying mechanisms driving the pain are poorly understood. In addition to persistent pain, patients with SCD are also in a tonically proinflammatory state. Previous studies have revealed that there are elevated plasma levels of many inflammatory mediators including chemokine (c-c motif) ligand 2 (CCL2) in individuals with SCD. Using a transgenic mouse model of SCD, we investigated the contributions of CCL2 signaling to SCD-related pain. Inhibition of chemokine receptor 2 ...
Source: Pain - July 26, 2018 Category: Anesthesiology Tags: Research Paper Source Type: research

Mice lacking Kcns1 in peripheral neurons show increased basal and neuropathic pain sensitivity
Voltage-gated potassium (Kv) channels are increasingly recognised as key regulators of nociceptive excitability. Kcns1 is one of the first potassium channels to be associated with neuronal hyperexcitability and mechanical sensitivity in the rat, as well as pain intensity and risk of developing chronic pain in humans. Here, we show that in mice, Kcns1 is predominantly expressed in the cell body and axons of myelinated sensory neurons positive for neurofilament-200, including Aδ-fiber nociceptors and low-threshold Aβ mechanoreceptors. In the spinal cord, Kcns1 was detected in laminae III to V of the dorsal horn wh...
Source: Pain - July 26, 2018 Category: Anesthesiology Tags: Research Paper Source Type: research

Development of pain in older adults: a latent class analysis of biopsychosocial risk factors
In this study, latent class analysis was used to identify biopsychosocial risk classes in people aged 50 years and older, from The Irish Longitudinal Study on Ageing, who reported not often being troubled by pain at wave 1 and completed the 2-year follow-up at wave 2 (n = 4458). Four classes were identified based on 11 potential risk factors at wave 1. These classes were characterised as “Low Risk,” “Physical Health Risk,” “Mental Health Risk,” and “High Risk.” The Low-Risk class accounted for over half the sample (51.2%), whereas the High-Risk class represented 7.8% of the s...
Source: Pain - July 26, 2018 Category: Anesthesiology Tags: Research Paper Source Type: research

Patients with chronic pain exhibit a complex relationship triad between pain, resilience, and within- and cross-network functional connectivity of the default mode network
Resilience is a psychological trait that strongly predicts chronic pain–related health outcomes. The neural correlates of both pain and trait resilience are critical to understand the brain–behaviour relationship in chronic pain; yet, neural correlates of resilience in chronic pain states are unknown. However, measures of pain perception and a wide range of psychological health measures have been linked to function of the default mode network (DMN). Thus, we aimed to determine the relationships between resilience, pain perception, and functional connectivity (FC) within the DMN and between the DMN and other bra...
Source: Pain - July 26, 2018 Category: Anesthesiology Tags: Research Paper Source Type: research

Mu-opioid receptors in nociceptive afferents produce a sustained suppression of hyperalgesia in chronic pain
The latent sensitization model of chronic pain reveals that recovery from some types of long-term hyperalgesia is an altered state in which nociceptive sensitization persists but is suppressed by the ongoing activity of analgesic receptors such as μ-opioid receptors (MORs). To determine whether these MORs are the ones present in nociceptive afferents, we bred mice expressing Cre-recombinase under the Nav1.8 channel promoter (Nav1.8cre) with MOR-floxed mice (flMOR). These Nav1.8cre/flMOR mice had reduced MOR expression in primary afferents, as revealed by quantitative PCR, in situ hybridization, and immunofluorescence co...
Source: Pain - July 26, 2018 Category: Anesthesiology Tags: Research Paper Source Type: research

Cortical astrocytes prime the induction of spine plasticity and mirror image pain
Peripheral nerve injury causes maladaptive plasticity in the central nervous system and induces chronic pain. In addition to the injured limb, abnormal pain sensation can appear in the limb contralateral to the injury, called mirror image pain. Because synaptic remodeling in the primary somatosensory cortex (S1) has critical roles in the induction of chronic pain, cortical reorganization in the S1 ipsilateral to the injured limb may also accompany mirror image pain. To elucidate this, we conducted in vivo 2-photon calcium imaging of neuron and astrocyte activity in the ipsilateral S1 after a peripheral nerve injury. We fou...
Source: Pain - July 26, 2018 Category: Anesthesiology Tags: Research Paper Source Type: research

Downregulation of adenosine and adenosine A1 receptor contributes to neuropathic pain in resiniferatoxin neuropathy
This study examined this system at the level of ligand (through the ectonucleotidase activity of prostatic acid phosphatase [PAP]) and adenosine A1 receptors (A1Rs) in resiniferatoxin (RTX) neuropathy, a peripheral neurodegenerative disorder that specifically affects nociceptive nerves expressing transient receptor potential vanilloid type 1 (TRPV1). We conducted immunohistochemistry on dorsal root ganglion (DRG) neurons, high-performance liquid chromatography for functional assays, and pharmacological interventions to alter PAP and A1Rs in mice with RTX neuropathy. In DRG of RTX neuropathy, PAP(+) neurons were reduced com...
Source: Pain - July 26, 2018 Category: Anesthesiology Tags: Research Paper Source Type: research

Dyadic analysis of siblings' relationship quality, behavioural responses, and pain experiences during experimental pain
This study examined whether sibling relationship quality was related to siblings' behaviours during experimental pain, and whether the behaviours of an observing sibling were related to children's pain outcomes. Ninety-two sibling dyads between 8 and 12 years old completed both observational and questionnaire measures of sibling relationship quality. Children took turns completing the cold-pressor task (CPT) in a counterbalanced order with their sibling present. Pain outcomes (intensity, fear, and tolerance) were recorded for each sibling, and the behaviour of the observing and participating siblings during the CPT were co...
Source: Pain - July 26, 2018 Category: Anesthesiology Tags: Research Paper Source Type: research

Clinical indications associated with opioid initiation for pain management in Ontario, Canada: a population-based cohort study
Concerns over prescription opioids contributing to high levels of opioid use disorder and overdose have led policymakers and clinicians to seek means to reduce inappropriate and high-dose initial prescriptions. To inform such efforts, we sought to describe the clinical indications associated with opioid initiation and the characteristics of the initial prescriptions and patients through a retrospective population-based cohort study. Our cohort included Ontarians initiating prescription opioids for pain management between April 1, 2015, and March 31, 2016. We identified the apparent clinical indication for opioid initiation...
Source: Pain - July 26, 2018 Category: Anesthesiology Tags: Research Paper Source Type: research

Neural pathways in medial septal cholinergic modulation of chronic pain: distinct contribution of the anterior cingulate cortex and ventral hippocampus
This study examined the contribution of MS cholinergic neurons and 2 neural pathways: MS–rostral anterior cingulate cortex (rACC) and MS–ventral hippocampal CA1 (vCA1), in modulating perceptual and affective pain behaviors in a mouse model of chronic inflammatory pain. We found that chronic pain activated MS cholinergic neurons and pyramidal neurons in the rACC, but suppressed pyramidal neuronal activities in the vCA1, all of which contributed to the maintenance of pathological pain. Chemogenetic inhibition of MS cholinergic neurons or the MS–rACC pathway inhibited rACC pyramidal neuronal activities and a...
Source: Pain - July 26, 2018 Category: Anesthesiology Tags: Research Paper Source Type: research

Sources of opioid medication for misuse in older adults: results from a nationally representative survey
Despite increasing rates of prescription opioid (PO) misuse in adults 50 years of age and older, little research has investigated such misuse in this population. This work aimed to examine sources of misused opioid medication in adults 50 years and older, with comparisons to younger groups. Data were from the 2009 to 2014 National Survey on Drug Use and Health surveys. Prevalence rates of PO sources, misuse, and PO use disorder (POUD) symptoms were estimated. Design-based logistic regression investigated age-based differences in these factors and the association of sources with POUD symptoms and other concurrent substance ...
Source: Pain - July 26, 2018 Category: Anesthesiology Tags: Research Paper Source Type: research

Modality-specific effects of aversive expectancy in the anterior insula and medial prefrontal cortex
We presented participants with visual cues predicting either a painful heat or disgusting odor, and assessed how they affected the subsequent subjective experience of stimuli from the same (within-modality) or opposite (cross-modal) modality. We found a reliable influence of expectancy on the subjective experience of stimuli whose modality matched that of the previous cue. At the brain level, this effect was mediated by the intermediate dysgranular section of the insula, whereas it was suppressed by more anterior agranular portions of the same region. Instead, no expectancy modulation was observed when the modality of the ...
Source: Pain - July 26, 2018 Category: Anesthesiology Tags: Research Paper Source Type: research

Cognitive impairment in a rat model of neuropathic pain: role of hippocampal microtubule stability
We report here that rats exhibited memory deficits after spared nerve injury (SNI). We found that levels of stable microtubule (MT) were increased in the hippocampus of the rats with memory deficits. This increase in stable MT is marked by α-tubulin hyperacetylation. Paclitaxel, a pharmacological MT stabilizer, increased the level of stable MT in the hippocampus and induced learning and memory deficits in normal rats. Furthermore, paclitaxel reduced long-term potentiation in hippocampal slices and increased stable MT (evidenced by α-tubulin hyperacetylation) levels in hippocampal neuronal cells. Intracerebroven...
Source: Pain - July 26, 2018 Category: Anesthesiology Tags: Research Paper Source Type: research

Comparison of the psychometric properties of 3 pain scales used in the pediatric emergency department: Visual Analogue Scale, Faces Pain Scale-Revised, and Colour Analogue Scale
Appropriate pain measurement relies on the use of valid, reliable tools. The aim of this study was to determine and compare the psychometric properties of 3 self-reported pain scales commonly used in the pediatric emergency department (ED). The inclusion criteria were children aged 6 to 17 years presenting to the ED with a musculoskeletal injury and self-reported pain scores ≥30 mm on the mechanical Visual Analogue Scale (VAS). Self-reported pain intensity was assessed using the mechanical VAS, Faces Pain Scale-Revised (FPS-R), and Colour Analogue Scale (CAS). Convergent validity was assessed by Pearson correlations and...
Source: Pain - July 26, 2018 Category: Anesthesiology Tags: Research Paper Source Type: research

Altered prefrontal correlates of monetary anticipation and outcome in chronic pain
Chronic pain may alter both affect- and value-related behaviors, which represents a potentially treatable aspect of chronic pain experience. Current understanding of how chronic pain influences the function of brain reward systems, however, is limited. Using a monetary incentive delay task and functional magnetic resonance imaging (fMRI), we measured neural correlates of reward anticipation and outcomes in female participants with the chronic pain condition of fibromyalgia (N = 17) and age-matched, pain-free, female controls (N = 15). We hypothesized that patients would demonstrate lower positive arousal, as well as altere...
Source: Pain - July 26, 2018 Category: Anesthesiology Tags: Research Paper Source Type: research

Wind-up in lamina I spinoparabrachial neurons: a role for reverberatory circuits
Wind-up is a frequency-dependent increase in the response of spinal cord neurons, which is believed to underlie temporal summation of nociceptive input. However, whether spinoparabrachial neurons, which likely contribute to the affective component of pain, undergo wind-up was unknown. Here, we addressed this question and investigated the underlying neural circuit. We show that one-fifth of lamina I spinoparabrachial neurons undergo wind-up, and provide evidence that wind-up in these cells is mediated in part by a network of spinal excitatory interneurons that show reverberating activity. These findings provide insight into...
Source: Pain - July 26, 2018 Category: Anesthesiology Tags: Research Paper Source Type: research

Associations between onset of effort-reward imbalance at work and onset of musculoskeletal pain: analyzing observational longitudinal data as pseudo-trials
Existing evidence of an association between effort-reward imbalance (ERI) at work and musculoskeletal pain is limited, preventing reliable conclusions about the magnitude and direction of the relation. In a large longitudinal study, we examined whether the onset of ERI is associated with subsequent onset of musculoskeletal pain among those free of pain at baseline, and vice versa, whether onset of pain leads to onset of ERI. Data were from the Swedish Longitudinal Occupational Survey of Health (SLOSH) study. We used responses from 3 consecutive study phases to examine whether exposure onset between the first and second pha...
Source: Pain - July 26, 2018 Category: Anesthesiology Tags: Research Paper Source Type: research