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No abstract available (Source: Pain)
Source: Pain - February 20, 2019 Category: Anesthesiology Tags: Correspondence Source Type: research

Efficacy of systemic lidocaine to reduce chronic postsurgical pain: case not yet closed…
No abstract available (Source: Pain)
Source: Pain - February 20, 2019 Category: Anesthesiology Tags: Correspondence Source Type: research

Pain assessment in advanced dementia. Validity of the German PAINAD—a prospective double-blind randomised placebo-controlled trial
Pain in combination with dementia is a common condition that makes pain recognition significantly more difficult. This results in undertreatment of pain in those suffering from dementia. The Pain Assessment in Advanced Dementia (PAINAD) scale currently represents one of the best approaches to pain detection in dementia. In a pilot study, strong inter-rater and retest reliability of the German version (PAINAD-G) was proven. However, the available data concerning the validity of this instrument were insufficient. The aim of the study was to validate the PAINAD-G scale by a double-blind randomised placebo-controlled trial in ...
Source: Pain - February 20, 2019 Category: Anesthesiology Tags: Research Paper Source Type: research

Whole-brain structural magnetic resonance imaging–based classification of primary dysmenorrhea in pain-free phase: a machine learning study
To develop a machine learning model to investigate the discriminative power of whole-brain gray-matter (GM) images derived from primary dysmenorrhea (PDM) women and healthy controls (HCs) during the pain-free phase and further evaluate the predictive ability of contributing features in predicting the variance in menstrual pain intensity. Sixty patients with PDM and 54 matched female HCs were recruited from the local university. All participants underwent the head and pelvic magnetic resonance imaging scans to calculate GM volume and myometrium-apparent diffusion coefficient (ADC) during their periovulatory phase. Questionn...
Source: Pain - February 20, 2019 Category: Anesthesiology Tags: Research Paper Source Type: research

Cortical integration of bilateral nociceptive signals: when more is less
Integration of nociceptive information is essential to produce adapted responses, to promote body integrity and survival. However, how the brain integrates nociceptive inputs from different body areas remains unknown. The aim of this study was to examine the cortical integration of bilateral nociceptive inputs evoked by laser heat stimuli. Sixteen healthy volunteers (8 F, 8 M; age: 25.5 ± 4.3) were recruited to participate in one session during which painful laser stimuli were applied to their hands with 2 Nd:YAP laser systems. Electroencephalographic activity was recorded to measure laser-evoked potentials and even...
Source: Pain - February 20, 2019 Category: Anesthesiology Tags: Research Paper Source Type: research

Islet-cell autoantigen 69 mediates the antihyperalgesic effects of electroacupuncture on inflammatory pain by regulating spinal glutamate receptor subunit 2 phosphorylation through protein interacting with C-kinase 1 in mice
In this study, we evaluated the role of ICA69 in the antihyperalgesic effects of EA and the underlying mechanism through regulation of GluR2 and PICK1 in spinal dorsal horn. Hyperalgesia was induced in mice with subcutaneous plantar injection of complete Freund adjuvant (CFA) to cause inflammatory pain. Electroacupuncture was then applied for 30 minutes every other day after CFA injection. When compared with CFA group, paw withdrawal frequency of CFA+EA group was significantly decreased. Remarkable increases in Ica1 mRNA expression and ICA69 protein levels on the ipsilateral side were detected in the CFA+EA group. ICA69 ex...
Source: Pain - February 20, 2019 Category: Anesthesiology Tags: Research Paper Source Type: research

Mechanisms underlying mechanical sensitization induced by complement C5a: the roles of macrophages, TRPV1, and calcitonin gene-related peptide receptors
The complement system significantly contributes to the development of inflammatory and neuropathic pain, but the underlying mechanisms are poorly understood. Recently, we identified the signaling pathway responsible for thermal hypersensitivity induced by the complement system component C5a. Here, we examine the mechanisms of another important action of C5a, induction of mechanical hypersensitivity. We found that intraplantar injection of C5a produced a dose-dependent mechanical sensitization and that this effect was blocked by chemogenetic ablation of macrophages in both male and female mice. Knockout of TRPV1 or pretreat...
Source: Pain - February 20, 2019 Category: Anesthesiology Tags: Research Paper Source Type: research

Pioglitazone, a PPARγ agonist, reduces cisplatin-evoked neuropathic pain by protecting against oxidative stress
Painful peripheral neuropathy is a dose-limiting side effect of cisplatin treatment. Using a murine model of cisplatin-induced hyperalgesia, we determined whether a PPARγ synthetic agonist, pioglitazone, attenuated the development of neuropathic pain and identified underlying mechanisms. Cisplatin produced mechanical and cold hyperalgesia and decreased electrical thresholds of Aδ and C fibers, which were attenuated by coadministration of pioglitazone (10 mg/kg, intraperitoneally [i.p.]) with cisplatin. Antihyperalgesic effects of pioglitazone were blocked by the PPARγ antagonist T0070907 (10 mg/kg, i.p.)....
Source: Pain - February 20, 2019 Category: Anesthesiology Tags: Research Paper Source Type: research

The association between endogenous opioid function and morphine responsiveness: a moderating role for endocannabinoids
We sought to replicate previous findings that low endogenous opioid (EO) function predicts greater morphine analgesia and extended these findings by examining whether circulating endocannabinoids and related lipids moderate EO-related predictive effects. Individuals with chronic low-back pain (n = 46) provided blood samples for endocannabinoid analyses, then underwent separate identical laboratory sessions under 3 drug conditions: saline placebo, intravenous (i.v.) naloxone (opioid antagonist; 12-mg total), and i.v. morphine (0.09-mg/kg total). During each session, participants rated low-back pain intensity, evoked heat pa...
Source: Pain - February 20, 2019 Category: Anesthesiology Tags: Research Paper Source Type: research

Obesity increases the risk of chronic pain development after motor vehicle collision
In this study, we evaluated the influence of body mass index on axial and overall MSP severity (0-10 numeric rating scale) 6 weeks, 6 months, and 1 year after MVC among 917 European Americans who presented to the emergency department for initial evaluation. After adjusting for an array of sociodemographic factors, obesity (particularly morbid obesity) was an independent risk factor for worse MSP after MVC (eg, RR 1.41 [95% CI 1.11, 1.80] for moderate or severe MSP 6 months after MVC among morbidly obese vs normal weight MVC survivors). Interestingly, substantial effect modification was observed between obesity risk and a g...
Source: Pain - February 20, 2019 Category: Anesthesiology Tags: Research Paper Source Type: research

The impact of anxiety on chronic musculoskeletal pain and the role of astrocyte activation
Anxiety and depression are associated with increased pain responses in chronic pain states. The extent to which anxiety drives chronic pain, or vice versa, remains an important question that has implications for analgesic treatment strategies. Here, the effect of existing anxiety on future osteoarthritis (OA) pain was investigated, and potential mechanisms were studied in an animal model. Pressure pain detection thresholds, anxiety, and depression were assessed in people with (n = 130) or without (n = 100) painful knee OA. Separately, knee pain and anxiety scores were also measured twice over 12 months in 4730 individuals ...
Source: Pain - February 20, 2019 Category: Anesthesiology Tags: Research Paper Source Type: research

Neonatal vincristine administration modulates intrinsic neuronal excitability in the rat dorsal root ganglion and spinal dorsal horn during adolescence
Our recent work has shown that the early-life administration of vincristine (VNC), commonly used to treat pediatric cancers, evokes mechanical pain hypersensitivity in rats that emerges during adolescence and persists into adulthood. However, the underlying mechanisms remain unclear, as nothing is known about how neonatal VNC treatment influences peripheral and central nociceptive processing at the cellular level. Here, we used in vitro intracellular microelectrode and whole-cell patch-clamp recordings to evaluate the consequences of early-life VNC administration on the intrinsic membrane properties of adolescent dorsal ro...
Source: Pain - February 20, 2019 Category: Anesthesiology Tags: Research Paper Source Type: research

Manual therapy prevents onset of nociceptor activity, sensorimotor dysfunction, and neural fibrosis induced by a volitional repetitive task
Painful and disabling musculoskeletal disorders remain prevalent. In rats trained to perform repetitive tasks leading to signs and dysfunction similar to those in humans, we tested whether manual therapy would prevent the development of the pathologies and symptoms. We collected behavioral, electrophysiological, and histological data from control rats, rats that trained for 5 weeks before performing a high-repetition high-force (HRHF) task for 3 weeks untreated, and trained rats that performed the task for 3 weeks while being treated 3x/week using modeled manual therapy (MMT) to the forearm (HRHF + MMT). The MMT included b...
Source: Pain - February 20, 2019 Category: Anesthesiology Tags: Research Paper Source Type: research

Decitabine attenuates nociceptive behavior in a murine model of bone cancer pain
In this study, we report that daily treatment with decitabine (2 µg/g, intraperitoneally) attenuated nociceptive behavior in the 4T1-luc2 mouse model of bone cancer pain. We hypothesized that the analgesic mechanism of decitabine involved activation of the endogenous opioid system through demethylation and reexpression of the transcriptionally silenced endothelin B receptor gene, Ednrb. Indeed, Ednrb was hypermethylated and transcriptionally silenced in the mouse model of bone cancer pain. We demonstrated that expression of Ednrb in the cancer cells lead to release of β-endorphin in the cell supernatant, which r...
Source: Pain - February 20, 2019 Category: Anesthesiology Tags: Research Paper Source Type: research

Distinct functions of soluble guanylyl cyclase isoforms NO-GC1 and NO-GC2 in inflammatory and neuropathic pain processing
A large body of evidence indicates that nitric oxide (NO)/cGMP signaling essentially contributes to the processing of chronic pain. In general, NO-induced cGMP formation is catalyzed by 2 isoforms of guanylyl cyclase, NO-sensitive guanylyl cyclase 1 (NO-GC1) and 2 (NO-GC2). However, the specific functions of the 2 isoforms in pain processing remain elusive. Here, we investigated the distribution of NO-GC1 and NO-GC2 in the spinal cord and dorsal root ganglia, and we characterized the behavior of mice lacking either isoform in animal models of pain. Using immunohistochemistry and in situ hybridization, we demonstrate that b...
Source: Pain - February 20, 2019 Category: Anesthesiology Tags: Research Paper Source Type: research

Preferred self-administered questionnaires to assess fear of movement, coping, self-efficacy, and catastrophizing in patients with musculoskeletal pain—A modified Delphi study
The way people with musculoskeletal disorders deal with pain influences their prognosis. Psychosocial factors that influence outcomes include fear of movement, coping, self-efficacy, and catastrophizing. A 3-round modified Delphi study was conducted with the aim to reach consensus on the most appropriate questionnaires to assess these 4 psychosocial factors in patients at risk of developing persistent musculoskeletal pain. The panel consisted of 36 experts, with track records in medicine, psychology, and allied health. To be considered an expert, a minimum number of authorships were required on research articles using self...
Source: Pain - February 20, 2019 Category: Anesthesiology Tags: Research Paper Source Type: research

Longitudinal pattern of pain medication utilization in peripheral neuropathy patients
In conclusion, opioid initiation and transition to chronic opioid therapy are frequent in a peripheral neuropathy population despite few patients receiving more than one guideline-recommended medication. Efforts to decrease opioid utilization and increase guideline-recommended medication use are needed to improve current neuropathic pain treatment. (Source: Pain)
Source: Pain - February 20, 2019 Category: Anesthesiology Tags: Research Paper Source Type: research

Genome-wide association reveals contribution of MRAS to painful temporomandibular disorder in males
Painful temporomandibular disorders (TMDs) are the leading cause of chronic orofacial pain, but its underlying molecular mechanisms remain obscure. Although many environmental factors have been associated with higher risk of developing painful TMD, family and twin studies support a heritable genetic component as well. We performed a genome-wide association study assuming an additive genetic model of TMD in a discovery cohort of 999 cases and 2031 TMD-free controls from the Orofacial Pain: Prospective Evaluation and Risk Assessment (OPPERA) study. Using logistic models adjusted for sex, age, enrollment site, and race, we id...
Source: Pain - February 20, 2019 Category: Anesthesiology Tags: Research Paper Source Type: research

The migraine eye: distinct rod-driven retinal pathways' response to dim light challenges the visual cortex hyperexcitability theory
Migraine-type photophobia, most commonly described as exacerbation of headache by light, affects nearly 90% of the patients. It is the most bothersome symptom accompanying an attack. Using subjective psychophysical assessments, we showed that migraine patients are more sensitive to all colors of light during ictal than during interictal phase and that control subjects do not experience pain when exposed to different colors of light. Based on these findings, we suggested that color preference is unique to migraineurs (as it was not found in control subjects) rather than migraine phase (as it was found in both phases). To id...
Source: Pain - February 20, 2019 Category: Anesthesiology Tags: Research Paper Source Type: research

CACNG2 polymorphisms associate with chronic pain after mastectomy
In this study, we revisited this claim by independently evaluating the proposed marker haplotype using 2 different patient cohorts recruited in different research settings. Meta-analysis of these new postmastectomy cohorts and the original cohort confirmed significant association of the CACNG2 haplotype with PMP. In addition, we tested whether the same markers would predict chronic postsurgical pain in men who underwent surgery for inguinal hernia repair, and whether there is significant genetic association with cutaneous thermal sensitivity in postmastectomy and postherniotomy patients. We found that the biomarker is sele...
Source: Pain - February 20, 2019 Category: Anesthesiology Tags: Research Paper Source Type: research

Machine learning–based prediction of clinical pain using multimodal neuroimaging and autonomic metrics
In this study, individualized physical maneuvers were used to exacerbate clinical pain in patients with chronic low back pain (N = 53), thereby experimentally producing lower and higher pain states. Multivariate machine-learning models were then built from brain imaging (resting-state blood-oxygenation-level-dependent and arterial spin labeling functional imaging) and autonomic activity (heart rate variability) features to predict within-patient clinical pain intensity states (ie, lower vs higher pain) and were then applied to predict between-patient clinical pain ratings with independent training and testing data sets. Wi...
Source: Pain - February 20, 2019 Category: Anesthesiology Tags: Research Paper Source Type: research

Facial muscle movements encoding pain—a systematic review
Facial expressions of pain are not undefined grimaces, but they convey specific information about the internal state of the individual in pain. With this systematic review, we aim to answer the question of which facial movements are displayed most consistently during pain. We searched for studies that used the Facial Action Coding System to analyze facial activity during pain in adults, and that report on distinct facial responses (action units [AUs]). Twenty-seven studies using experimental pain and 10 clinical pain studies were included. We synthesized the data by taking into consideration (1) the criteria used to define...
Source: Pain - February 20, 2019 Category: Anesthesiology Tags: Systematic Review and Meta-Analysis Source Type: research

Improving pain and sleep in middle-aged and older adults: the promise of behavioral sleep interventions
No abstract available (Source: Pain)
Source: Pain - February 20, 2019 Category: Anesthesiology Tags: Topical Review Source Type: research

Vti1b promotes TRPV1 sensitization during inflammatory pain
Sensitization of the transient receptor potential ion channel vanilloid 1 (TRPV1) is critically involved in inflammatory pain. To date, manifold signaling cascades have been shown to converge onto TRPV1 and enhance its sensitization. However, many of them also play a role for nociceptive pain, which limits their utility as targets for therapeutic intervention. Here, we show that the vesicle transport through interaction with t-SNAREs homolog 1B (Vti1b) protein promotes TRPV1 sensitization upon inflammation in cell culture but leaves normal functioning of TRPV1 intact. Importantly, the effect of Vti1b can be recapitulated i...
Source: Pain - January 24, 2019 Category: Anesthesiology Tags: Research Paper Source Type: research

What is the effect of alcohol consumption on the risk of chronic widespread pain? A Mendelian randomisation study using UK Biobank
Studies have shown that moderate alcohol consumption is strongly associated with reduced reporting of chronic widespread pain (CWP). The study designs used, however, are prone to confounding and are not able to establish the direction of causality. The current study overcomes these problems using the Mendelian randomisation design to determine the effect of alcohol consumption on the likelihood of reporting CWP. The UK Biobank recruited 500,000 participants aged between 40 and 69 years. Data collected included questions on chronic pain and alcohol consumption, and biological samples providing genotypic information. Alcohol...
Source: Pain - January 24, 2019 Category: Anesthesiology Tags: Research Paper Source Type: research

Behavioural discrimination of noxious stimuli in infants is dependent on brain maturation
Changes in facial expression are an essential form of social communication and in nonverbal infants are often used to alert care providers to pain-related distress. However, studies of early human brain development suggest that premature infants aged less than 34 weeks' gestation do not display discriminative brain activity patterns to equally salient noxious and innocuous events. Here we examine the development of facial expression in 105 infants, aged between 28 and 42 weeks' gestation. We show that the presence of facial expression change after noxious and innocuous stimulation is age-dependent and that discriminative f...
Source: Pain - January 24, 2019 Category: Anesthesiology Tags: Research Paper Source Type: research

Mechanistic pain profiling as a tool to predict the efficacy of 3-week nonsteroidal anti-inflammatory drugs plus paracetamol in patients with painful knee osteoarthritis
Joint inflammation is present in a subpopulation of knee osteoarthritis (OA) patients. Proinflammatory cytokines are known to sensitize the peripheral and central pain pathways. This can be mechanistically assessed by pressure pain thresholds and temporal summation of pain (TSP). Nonsteroidal anti-inflammatory drugs (NSAIDs) combined with paracetamol are recommended as OA treatment. The current study hypothesized that evidence of central sensitization would predict poor responses to peripherally directed therapies in knee OA and therefore aimed to investigate the value of mechanistic pain profiling for predicting pain outc...
Source: Pain - January 24, 2019 Category: Anesthesiology Tags: Research Paper Source Type: research

Comprehensive analysis of long noncoding RNA expression in dorsal root ganglion reveals cell-type specificity and dysregulation after nerve injury
This study presents tissue and neuron-specific expression profiling of both known and novel long noncoding RNAs (LncRNAs) in the rodent DRG after nerve injury. We have identified a large number of novel LncRNAs expressed within the rodent DRG, a minority of which were syntenically conserved between the mouse, rat, and human, and including, both intergenic and antisense LncRNAs. We have also identified neuron type–specific LncRNAs in the mouse DRG and LncRNAs that are expressed in human IPS cell–derived sensory neurons. We show significant plasticity in LncRNA expression after nerve injury, which in mice is stra...
Source: Pain - January 24, 2019 Category: Anesthesiology Tags: Research Paper Source Type: research

Morphological and functional properties distinguish the substance P and gastrin-releasing peptide subsets of excitatory interneuron in the spinal cord dorsal horn
Excitatory interneurons account for the majority of neurons in the superficial dorsal horn, but despite their presumed contribution to pain and itch, there is still limited information about their organisation and function. We recently identified 2 populations of excitatory interneuron defined by expression of gastrin-releasing peptide (GRP) or substance P (SP). Here, we demonstrate that these cells show major differences in their morphological, electrophysiological, and pharmacological properties. Based on their somatodendritic morphology and firing patterns, we propose that the SP cells correspond to radial cells, which ...
Source: Pain - January 24, 2019 Category: Anesthesiology Tags: Research Paper Source Type: research

Long-term outcomes of adolescents with juvenile-onset fibromyalgia into adulthood and impact of depressive symptoms on functioning over time
The objectives of this study were to describe physical and psychosocial outcomes of youth diagnosed with JFM in early adulthood (∼8-year follow-up), examine longitudinal trajectories of pain and depressive symptoms from adolescence to young adulthood, and examine the impact of pain and depressive symptoms on physical functioning over time. Participants were 97 youth with JFM enrolled in a prospective longitudinal study in which pain symptoms, and physical and psychosocial functioning were assessed at 4 time points over approximately 8 years. At the time 4 follow-up (Mage = 24.2 years), the majority continued to suffer ...
Source: Pain - January 24, 2019 Category: Anesthesiology Tags: Research Paper Source Type: research

The association between multiple sclerosis and pain medications
The patients with multiple sclerosis (MS) are at greater risk of pain than people without the disease; however, the occurrence and characteristics of pain among these patients are incompletely described. We aimed to assess characteristics of pain amongst MS patients using MS patients who were recruited to participate in 3 studies in Sweden (n = 3877) and were matched with individuals without MS (n = 4548) by sex, year of birth, and region of residence. The Prescribed Drugs Register identified prescribed pain medication, overall and restricted to those given 4 or more prescriptions in 1 year to assess chronic pain. Anatomic...
Source: Pain - January 24, 2019 Category: Anesthesiology Tags: Research Paper Source Type: research

Incident opioid use and risk of hip fracture among persons with Alzheimer disease: a nationwide matched cohort study
The objective of this study was to investigate whether incident opioid use is associated with an increased risk of hip fractures among community-dwelling persons with Alzheimer disease (AD) and to assess the association in terms of duration of use and opioid strength. Among community-dwelling persons with AD diagnosed in 2010 to 2011 (N = 23,100), a matched cohort study comparing incident opioid users (N = 4750) with opioid nonusers (N = 4750) was constructed. Matching was based on age, sex, and time since AD diagnosis at opioid initiation. Data on drug use and hip fractures were retrieved from nationwide registers. Incide...
Source: Pain - January 24, 2019 Category: Anesthesiology Tags: Research Paper Source Type: research

Children and adolescents with sickle cell disease have worse cold and mechanical hypersensitivity during acute painful events
Sickle cell disease (SCD) pain associates with cold temperature and touch. Patients and murine models with SCD have baseline thermal and mechanical pain. In SCD mice, the baseline hypersensitivity is exacerbated by experimental vaso-occlusive crises. We hypothesized that patients with SCD will similarly experience increased hypersensitivity to thermal and mechanical stimuli during acute painful events compared with baseline health. We conducted a prospective study of 24 patients with SCD aged 7 to 19 years. Patients underwent quantitative sensory testing to thermal (cold/heat) and mechanical stimuli on the thenar eminence ...
Source: Pain - January 24, 2019 Category: Anesthesiology Tags: Research Paper Source Type: research

Perceptions of gendered and ungendered pain relief norms and stereotypes using Q-methodology
Pain is ubiquitous, but effective pain relief eludes many. Research has shown that some pain behaviours are perceived as gendered, and this may influence the way men and women express and cope with pain, but such enquiries have not extended to specific methods of pain relief. Our aim was to explore perceptions of the most socially acceptable ways for men and women to relieve pain. Across 2 studies, 60 participants (50% men) aged 18 to 78 years completed a Q-sort task, sorting different pain relief strategies by the social acceptability for either women (study 1; N = 30) or men (study 2; N = 30). Analyses revealed 2 stereot...
Source: Pain - January 24, 2019 Category: Anesthesiology Tags: Research Paper Source Type: research

Divergent influences of the locus coeruleus on migraine pathophysiology
Migraine is a common disabling neurological condition that is associated with several premonitory symptoms that can occur days before the headache onset. The most commonly reported premonitory symptom is marked fatigue that has been shown to be highly predictive of an ensuing migraine attack. The locus coeruleus (LC) is a key nucleus involved in arousal that has also been shown to impact pain processing. It provides one of the major sources of noradrenaline to the dorsal horn of the spinal cord and neocortex. Given the clinical association between migraine, sleep–wake regulation, and fatigue, we sought to determine w...
Source: Pain - January 24, 2019 Category: Anesthesiology Tags: Research Paper Source Type: research

Contribution of dorsal root ganglion octamer transcription factor 1 to neuropathic pain after peripheral nerve injury
In this study, we investigated whether octamer transcription factor 1 (OCT1), a transcription factor, contributed to neuropathic pain caused by chronic constriction injury (CCI) of the sciatic nerve. Chronic constriction injury produced a time-dependent increase in the level of OCT1 protein in the ipsilateral L4/5 DRG, but not in the spinal cord. Blocking this increase through microinjection of OCT1 siRNA into the ipsilateral L4/5 DRG attenuated the initiation and maintenance of CCI-induced mechanical allodynia, heat hyperalgesia, and cold allodynia and improved morphine analgesia after CCI, without affecting basal respons...
Source: Pain - January 24, 2019 Category: Anesthesiology Tags: Research Paper Source Type: research

PRISM: a brief screening tool to identify risk in parents of youth with chronic pain
Having a child with chronic pain impacts a parent's life. Reciprocally, parent cognitive, affective, and behavioral responses to the child's chronic pain can influence the child's pain experience. The purpose of this study is to develop a brief self-report screening tool (Parent Risk and Impact Screening Measure [PRISM]) of parent psychosocial functioning and behavioral responses to child pain. This measure assesses parents' reports of their own stress, health, psychosocial functioning, and disruption in activities due to their child's pain and related disability. In an effort to preliminarily validate this screening tool,...
Source: Pain - January 24, 2019 Category: Anesthesiology Tags: Research Paper Source Type: research

Increased pain sensitivity and decreased opioid analgesia in T-cell-deficient mice and implications for sex differences
The processing of pain in the central nervous system is now known to have an important immune component, including T cells of the adaptive immune system. T cells have been shown to release endogenous opioids, and although it is well known that opioids have effects on T-cell populations, very little attention has been given to the converse: how T cells may affect opioid regulation. We find here that, in addition to displaying significantly increased baseline pain sensitivity across various pain modalities, T-cell-deficient mice (CD-1 nude, Rag1 null mutant, and Cd4 null mutant) exhibit pronounced deficiencies in morphine in...
Source: Pain - January 24, 2019 Category: Anesthesiology Tags: Research Paper Source Type: research

Acquisition of analgesic properties by the cholecystokinin (CCK)/CCK2 receptor system within the amygdala in a persistent inflammatory pain condition
Pain is associated with negative emotions such as anxiety, but the underlying neurocircuitry and modulators of the association of pain and anxiety remain unclear. The neuropeptide cholecystokinin (CCK) has both pronociceptive and anxiogenic properties, so we explored the role of CCK in anxiety and nociception in the central amygdala (CeA), a key area in control of emotions and descending pain pathways. Local infusion of CCK into the CeA of control rats increased anxiety, as measured in the light–dark box test, but had no effect on mechanical sensitivity. By contrast, intra-CeA CCK infusion 4 days after Complete Freun...
Source: Pain - January 24, 2019 Category: Anesthesiology Tags: Research Paper Source Type: research

Dopamine receptor D2, but not D1, mediates descending dopaminergic pathway–produced analgesic effect in a trigeminal neuropathic pain mouse model
Neuropathic pain represents a challenge to clinicians because it is resistant to commonly prescribed analgesics due to its largely unknown mechanisms. Here, we investigated a descending dopaminergic pathway–mediated modulation of trigeminal neuropathic pain. We performed chronic constriction injury of the infraorbital nerve from the maxillary branch of trigeminal nerve to induce trigeminal neuropathic pain in mice. Our retrograde tracing showed that the descending dopaminergic projection from hypothalamic A11 nucleus to spinal trigeminal nucleus caudalis is bilateral. Optogenetic/chemogenetic manipulation of dopamine...
Source: Pain - January 24, 2019 Category: Anesthesiology Tags: Research Paper Source Type: research

Parental emotion and pain control behaviour when faced with child's pain: the emotion regulatory role of parental pain-related attention-set shifting and heart rate variability
This study investigated the moderating role of parental pain-related attention-set shifting and heart rate variability (HRV) for parental distress and pain control behaviour when faced with their child's pain. Participants were 54 schoolchildren and one of their parents. Parental HRV was assessed at study commencement followed by a cued-switching task indexing parental ability to flexibly shift attention between pain-related and neutral attentional sets. In a subsequent phase, parents observed their child perform a cold-pressor task [CPT], allowing for assessment of parental pain control behavior (indexed by latency to sto...
Source: Pain - January 24, 2019 Category: Anesthesiology Tags: Research Paper Source Type: research

Dual enkephalinase inhibitor PL265: a novel topical treatment to alleviate corneal pain and inflammation
Ocular pain is a core symptom of inflammatory or traumatic disorders affecting the anterior segment. To date, the management of chronic ocular pain remains a therapeutic challenge in ophthalmology. The main endogenous opioids (enkephalins) play a key role in pain control but exhibit only transient analgesic effects due to their rapid degradation. The aim of this study was to explore the antinociceptive and anti-inflammatory effects of topical administration of PL265 (a dual enkephalinase inhibitor) on murine models of corneal pain. On healthy corneas, chronic PL265 topical administration did not alter corneal integrity nor...
Source: Pain - January 24, 2019 Category: Anesthesiology Tags: Research Paper Source Type: research

Social representations of chronic pain in newspapers, online media, and film
Social representation theory provides a framework for studying how scientific knowledge affects common sense and communication through inquiries into everyday discourse. This qualitative study examined social representations of chronic pain from 4 sources: North American newspapers; “Chronic Illness Cat” memes from the social media web site, Pinterest; video blogs on YouTube; and from a 2014 film, Cake, and interviews and comments concerning it. Using thematic analysis, we first identified social representations found in our 4 sources and others found in 1 or 2 of them. Second, we analyzed the sources for their...
Source: Pain - January 24, 2019 Category: Anesthesiology Tags: Research Paper Source Type: research

Structural, functional, and symptom relations in painful distal symmetric polyneuropathies: a systematic review
The diagnosis of distal symmetric polyneuropathies (DSPs) relies on the presenting symptomatology and neurological sensory examination, supported by objectively quantified structural and functional changes in sensory nerves. Although these separate components have important diagnostic utility, the associations between the structural vs the symptomatic and functional findings in painful DSP are still unclear. It is assumed that delineation of the correlations, or lack of such, between structure, clinical presentation, and function will contribute to a better understanding and treatment of DSP. This systematic review assesse...
Source: Pain - January 24, 2019 Category: Anesthesiology Tags: Systematic Review and Meta-Analysis Source Type: research

Pain that does not interfere with daily life—a new focus for population epidemiology and public health?
No abstract available (Source: Pain)
Source: Pain - January 24, 2019 Category: Anesthesiology Tags: Topical Review Source Type: research

Clarifying our cultural contest about chronic pain
No abstract available (Source: Pain)
Source: Pain - January 24, 2019 Category: Anesthesiology Tags: Commentary Source Type: research

Targeting the Nav1.8 ion channel engenders sex-specific responses in lysophosphatidic acid–induced joint neuropathy
Joint neuropathic pain occurs in a subset of arthritis patients, and lysophosphatidic acid (LPA) has been implicated as a mediator of joint neuropathy. The mechanism by which LPA promotes neuropathic pain is unknown but may be related to altered signalling of the voltage-gated sodium channel Nav1.8 located on nociceptors. Because arthritis and neuropathic pain are more prevalent in females, this study aimed to explore potential sex differences in the development of LPA-induced joint neuropathy and whether Nav1.8 played a role in the associated neuropathic pain. Joint neuropathy was induced in male and female Wistar rats (1...
Source: Pain - December 27, 2018 Category: Anesthesiology Tags: Research Paper Source Type: research

Associations of catechol-O-methyltransferase (rs4680) single nucleotide polymorphisms with opioid use and dose among adults with chronic pain
This study extends key knowledge about the influence of the Met/Met genotype and Met allele on opioid use in adults with chronic pain. (Source: Pain)
Source: Pain - December 27, 2018 Category: Anesthesiology Tags: Research Paper Source Type: research

How variability in pain and pain coping relate to pain interference during multistage ultramarathons
This study reports on pain coping in 204 entrants in 2016 RacingThePlanet multistage ultramarathon events. Participants provided data over 5 consecutive days on pain severity, pain interference, exertion, and coping. Results demonstrated that the study participants were more likely to use adaptive than maladaptive coping responses. However, maladaptive coping, but not adaptive coping, was positively associated with percent time spent thinking about pain and pain-related interference. Taken together, the study supports the idea that this high functioning group of individuals experiencing pain emphasizes the use of adaptive ...
Source: Pain - December 27, 2018 Category: Anesthesiology Tags: Research Paper Source Type: research

What makes surgical nerve injury painful? A 4-year to 9-year follow-up of patients with intercostobrachial nerve resection in women treated for breast cancer
In this study, we examined 251 breast cancer survivors with surgeon-verified intercostobrachial nerve resection to identify factors that associate with CPSNP. The patients were recruited from a previous study of 1000 women treated for breast cancer in 2006 to 2010. This enabled us to analyze preoperative factors that associate with future CPSNP. The patients were re-examined in 2014 to 2016 to diagnose CPSNP using the revised NP diagnostic criteria. Preoperative assessments were pain in the area to be operated on, any chronic pain condition, depressive symptoms, anxiety, sleep, and experimental cold pain sensitivity using ...
Source: Pain - December 27, 2018 Category: Anesthesiology Tags: Research Paper Source Type: research