Thank you to PAIN reviewers
No abstract available (Source: Pain)
Source: Pain - November 20, 2018 Category: Anesthesiology Tags: Thanks to reviewers Source Type: research

Reply
No abstract available (Source: Pain)
Source: Pain - November 20, 2018 Category: Anesthesiology Tags: Correspondence Source Type: research

Adrenal suppression after epidural steroids
No abstract available (Source: Pain)
Source: Pain - November 20, 2018 Category: Anesthesiology Tags: Correspondence Source Type: research

Do patients with interictal migraine modulate pain differently from healthy controls? A psychophysical and brain imaging study
Studies in interictal migraine show either normal or impaired pain modulation, at the psychophysical level. To date, pain modulation in migraineurs has yet to be explored concurrent with imaging methods. We aimed to investigate brain activity associated with endogenous analgesia by functional magnetic resonance imaging in attack-free migraineurs. Thirty-nine episodic migraineurs and 35 controls participated. Endogenous analgesia efficiency was assessed by the conditioned pain modulation (CPM) paradigm during functional magnetic resonance imaging. Conditioned pain modulation included 4 stimulation sequences of either test s...
Source: Pain - November 20, 2018 Category: Anesthesiology Tags: Research Paper Source Type: research

A cross-sectional study investigating frequency and features of definitely diagnosed diabetic painful polyneuropathy
This cross-sectional multicentre study aimed at investigating frequency and features of painful diabetic polyneuropathy. We consecutively enrolled 816 patients attending hospital diabetic outpatient clinics. We first definitely diagnosed diabetic polyneuropathy and pure small-fibre polyneuropathy using clinical examination, nerve conduction study, and skin biopsy or quantitative sensory testing. Adhering to widely agreed criteria, we then identified neuropathic pain and diagnosed painful polyneuropathy using a combined approach of clinical examination and diagnostic tests. Of the 816 patients, 36% had a diabetic polyneurop...
Source: Pain - November 20, 2018 Category: Anesthesiology Tags: Research Paper Source Type: research

Comparison of masseter muscle referred sensations after mechanical and glutamate stimulation: a randomized, double-blind, controlled, cross-over study
Referred sensations (RS) are commonly found in various musculoskeletal pain conditions. Experimental studies have shown that RS can be elicited through glutamate injection and mechanical stimulation. Despite this, differences and similarities between these modalities in RS outcomes remain unclear. The aim of this study was to assess differences between mechanical-induced and glutamate injection–induced RS in the trigeminal region. The present randomized, double-blind, controlled, cross-over study recruited 60 healthy participants who were assessed in 2 different sessions. In both sessions, pressure was applied to the...
Source: Pain - November 20, 2018 Category: Anesthesiology Tags: Research Paper Source Type: research

Interactive effects of conditioned pain modulation and temporal summation of pain—the role of stimulus modality
This study aimed at investigating these differential effects of stimulus modality. Thirty-five healthy volunteers completed 2 experimental blocks (Ts modality: pressure vs heat) in balanced order. Both blocks consisted of 3 conditions: baseline (no CS), CPM1 (nonpainful CS: 42°C water bath), and CPM2 (painful CS: 46°C water bath). Single stimuli and series of stimuli were alternatingly applied to assess TSP by means of a Numerical Rating Scale. Both TSP and CPM were successfully induced with no difference between the 2 Ts modalities. We also detected a significant interaction between TSP and CPM, with higher pain r...
Source: Pain - November 20, 2018 Category: Anesthesiology Tags: Research Paper Source Type: research

Pharmacological rescue of nociceptive hypersensitivity and oxytocin analgesia impairment in a rat model of neonatal maternal separation
This study suggests that these alterations might be restored while stimulating OT receptor signaling or histone deacetylase inhibitors, using molecules that are currently available or part of clinical trials for other pathologies. (Source: Pain)
Source: Pain - November 20, 2018 Category: Anesthesiology Tags: Research Paper Source Type: research

Inhibition of spinal 15-LOX-1 attenuates TLR4-dependent, nonsteroidal anti-inflammatory drug–unresponsive hyperalgesia in male rats
Although nonsteroidal anti-inflammatory drugs are the first line of therapeutics for the treatment of mild to moderate somatic pain, they are not generally considered to be effective for neuropathic pain. In the current study, direct activation of spinal Toll-like 4 receptors (TLR4) by the intrathecal (IT) administration of KDO2 lipid A (KLA), the active component of lipopolysaccharide, elicits a robust tactile allodynia that is unresponsive to cyclooxygenase inhibition, despite elevated expression of cyclooxygenase metabolites in the spinal cord. Intrathecal KLA increases 12-lipoxygenase-mediated hepoxilin production in t...
Source: Pain - November 20, 2018 Category: Anesthesiology Tags: Research Paper Source Type: research

The onset of treatment with the antidepressant desipramine is critical for the emotional consequences of neuropathic pain
In this study, we evaluated the efficacy of the tricyclic antidepressant desipramine (DMI, a noradrenaline reuptake inhibitor) in preventing or relieving the noradrenergic impairment induced by neuropathic pain. The treatment started before or after the onset of the anxiodepressive phenotype (“early or late treatment”) in adult rats subjected to chronic sciatic constriction. Electrophysiological and western blotting assays showed LC dysfunction (increased bursting activity, alpha2-adrenoceptor sensitivity, tyrosine hydroxylase, and noradrenaline transporter expression) in chronic constriction injury at long ter...
Source: Pain - November 20, 2018 Category: Anesthesiology Tags: Research Paper Source Type: research

Quality indicators to assess quality of pain clinic care from the perspective of patients with chronic pain: development, usability, comprehensibility, and psychometric quality of the QiPPP questionnaire
To address the lack of appropriate patient-defined quality indicators (QIs) for assessment of pain clinic care in the Netherlands, we developed the “Quality Indicators Pain Patients' Perspective” (QiPPP) questionnaire. Quality indicators are widely used to measure the quality of the structure, process, and outcome of health care. The Pain Patient United Consortium, together with the University Pain Centre of Maastricht, developed QIs for assessment of care. The aim of this study was to develop QIs from the perspective of patients with chronic pain for assessment of the care provided by a pain clinic, and to val...
Source: Pain - November 20, 2018 Category: Anesthesiology Tags: Research Paper Source Type: research

The opioid receptor mu 1 (OPRM1) rs1799971 and catechol-O-methyltransferase (COMT) rs4680 as genetic markers for placebo analgesia
The placebo effect is considered the core example of mind–body interactions. However, individual differences produce large placebo response variability in both healthy volunteers and patients. The placebo response in pain, placebo analgesia, may be dependent on both the opioid system and the dopaminergic system. Previous studies suggest that genetic variability affects the function of these 2 systems. The aim of this study was therefore to address the interaction between the single nucleotide polymorphisms opioid receptor mu 1 (OPRM1) rs1799971 and catechol-O-methyltransferase (COMT) rs4680 on placebo analgesia. Two ...
Source: Pain - November 20, 2018 Category: Anesthesiology Tags: Research Paper Source Type: research

Tetrodotoxin-sensitive voltage-gated sodium channels regulate bladder afferent responses to distension
Interstitial cystitis/bladder pain syndrome (IC/BPS) is a prevalent, chronic bladder disorder that negatively impacts the quality of life for ∼5% of the western population. Hypersensitivity of mechanosensory afferents embedded within the bladder wall is considered a key component in mediating IC/BPS symptoms. Bladder infusion of voltage-gated sodium (Nav) channel blockers show clinical efficacy in treating IC/BPS symptoms; however, the current repertoire of Nav channels expressed by and contributing to bladder afferent function is unknown. We used single-cell reverse-transcription polymerase chain reaction of retrograd...
Source: Pain - November 20, 2018 Category: Anesthesiology Tags: Research Paper Source Type: research

Multi-OMICS analyses of frailty and chronic widespread musculoskeletal pain suggest involvement of shared neurological pathways
Chronic widespread musculoskeletal pain (CWP) and frailty are prevalent conditions in older people. We have shown previously that interindividual variation in frailty and CWP is genetically determined. We also reported an association of frailty and CWP caused by shared genetic and common environmental factors. The aim of this study was to use omic approaches to identify molecular genetic factors underlying the heritability of frailty and its genetic correlation with CWP. Frailty was quantified through the Rockwood Frailty Index (FI) as a proportion of deficits from 33 binary health deficit questions in 3626 female twins. C...
Source: Pain - November 20, 2018 Category: Anesthesiology Tags: Research Paper Source Type: research

Functional brain activity during motor control and pain processing in chronic jaw pain
We report 2 novel findings. First, although the parameters of grip force production were similar between the groups, the functional activity in regions including the prefrontal cortex, insula, and thalamus best separated the groups. Second, although stimulus intensity and pain perception were similar between the groups, functional activity in brain regions including the dorsal lateral prefrontal cortex, rostral ventral premotor cortex, and inferior parietal lobule best separated the groups. Our observations suggest that chronic jaw pain is associated with changes in how the brain processes motor and pain-related informatio...
Source: Pain - November 20, 2018 Category: Anesthesiology Tags: Research Paper Source Type: research

Neuroprotective effect of angiotensin II type 2 receptor stimulation in vincristine-induced mechanical allodynia
Peripheral neuropathy is the major dose-limiting side effect of many currently used chemotherapies, such as vincristine (VCR). We recently demonstrated that candesartan, an angiotensin II type 1 receptor antagonist, was neuroprotective against resiniferatoxin-induced sensory neuropathy, and that this effect is mediated by stimulation of the angiotensin II type 2 receptor (AT2R). Thus, we evaluated the effect of preventive treatment with candesartan and a specific AT2R agonist, C21, on a mouse model of VCR-induced neuropathy. Vincristine was administered daily for 7 days to male Swiss mice. Treatment with candesartan and C2...
Source: Pain - November 20, 2018 Category: Anesthesiology Tags: Research Paper Source Type: research

Young females with long-standing patellofemoral pain display impaired conditioned pain modulation, increased temporal summation of pain, and widespread hyperalgesia
This study investigated antinociceptive and pronociceptive profiles in young females with long-standing (>5 years) PFP (current-PFP), those who recovered from adolescent PFP (recovered-PFP), and pain-free controls. This preregistered, assessor-blinded, cross-sectional study included 87 females younger than 25 years: 36 current-PFP, 22 recovered-PFP, and 29 pain-free controls. The primary outcome was conditioned pain modulation (CPM) assessed by increase of cuff pain thresholds during painful cuff conditioning on the contralateral leg. Secondary outcomes included pressure pain thresholds at the knee, shin, and forearm, a...
Source: Pain - November 20, 2018 Category: Anesthesiology Tags: Research Paper Source Type: research

Patterns of pain-related activity: replicability, treatment-related changes, and relationship to functioning
Changes in activity patterns frequently accompany the experience of chronic pain. Two activity patterns, avoidance and overdoing, are hypothesized to contribute to the development of ongoing pain and pain-related disability, while activity pacing is frequently introduced to enhance pain management and functioning. Two studies were conducted to assess whether reliable subgroups with differing activity patterns could be identified in different pain populations and to evaluate changes in these subgroups after a group format, pain management program. In study 1, individuals with ongoing pain being assessed for treatment at 2 d...
Source: Pain - November 20, 2018 Category: Anesthesiology Tags: Research Paper Source Type: research

Morphine effects within the rodent anterior cingulate cortex and rostral ventromedial medulla reveal separable modulation of affective and sensory qualities of acute or chronic pain
Modulation of pain may result from engagement of opioid receptors in multiple brain regions. Whether sensory and affective qualities of pain are differentially affected by brain opioid receptor circuits remains unclear. We previously reported that opioid actions within the rostral anterior cingulate cortex (ACC) produce selective modulation of affective qualities of neuropathic pain in rodents, but whether such effects may occur in other areas of the ACC is not known. Here, morphine was microinjected into 3 regions of the ACC or into the rostral ventromedial medulla (RVM), and pain behaviors in naive, sham, or spinal nerve...
Source: Pain - November 20, 2018 Category: Anesthesiology Tags: Research Paper Source Type: research

Moment-to-moment changes in perceived social support and pain for men living with HIV: an experience sampling study
Research suggests that people living with HIV experience levels of pain disproportionate to the general population. Pain is a stressor that can negatively impact health-related quality of life. As the number of people aging with HIV increases, we must understand the dynamics of pain experiences among people living with HIV and how to effectively harness evidence-based treatments and supportive resources to enhance adaptive coping. We used an experience sampling method (also called Ecological Momentary Assessment) to assess moment-to-moment experiences of pain and social support 3 times a day for 7 days in a sample of 109 m...
Source: Pain - November 20, 2018 Category: Anesthesiology Tags: Research Paper Source Type: research

Experimental muscle hyperalgesia modulates sensorimotor cortical excitability, which is partially altered by unaccustomed exercise
In this study, sensorimotor cortical changes were investigated using a model of persistent pain combined with an overloading condition. In 24 healthy subjects, the effect of nerve growth factor (NGF)-induced pain, combined with delayed-onset muscle soreness (DOMS), was examined on pain perception, pressure pain sensitivity, maximal force, and sensorimotor cortical excitability. Two groups (NGF alone and NGF + DOMS) received injections of NGF into the extensor carpi radialis brevis (ECRB) muscle at day 0, day 2, and day 4. At day 4, the NGF + DOMS group undertook wrist eccentric exercise to induce DOMS in the ECRB muscle. M...
Source: Pain - November 20, 2018 Category: Anesthesiology Tags: Research Paper Source Type: research

Left dorsolateral prefrontal cortex repetitive transcranial magnetic stimulation reduces the development of long-term muscle pain
The left dorsolateral prefrontal cortex (DLPFC) is involved in the experience and modulation of pain, and may be an important node linking pain and cognition. Repetitive transcranial magnetic stimulation (rTMS) to the left DLPFC can reduce chronic and experimental pain. However, whether left DLPFC rTMS can influence the development of chronic pain is unknown. Using repeated intramuscular injection of nerve growth factor to induce the development of sustained muscle pain (lasting weeks), 30 healthy individuals were randomized to receive 5 consecutive daily treatments of active or sham left DLPFC rTMS, starting before the fi...
Source: Pain - November 20, 2018 Category: Anesthesiology Tags: Research Paper Source Type: research

Neural mechanisms supporting the relationship between dispositional mindfulness and pain
Interindividual differences in pain sensitivity vary as a function of interactions between sensory, cognitive–affective, and dispositional factors. Trait mindfulness, characterized as the innate capacity to nonreactively sustain attention to the present moment, is a psychological construct that is associated with lower clinical pain outcomes. Yet, the neural mechanisms supporting dispositional mindfulness are unknown. In an exploratory data analysis obtained during a study comparing mindfulness to placebo analgesia, we sought to determine whether dispositional mindfulness is associated with lower pain sensitivity. We...
Source: Pain - November 20, 2018 Category: Anesthesiology Tags: Research Paper Source Type: research

Psychosocial factors associated with persistent pain in people with HIV: a systematic review with meta-analysis
Chronic pain remains a prevalent and disabling problem for people living with HIV in the current antiretroviral treatment era. Psychosocial treatments may have promise for managing the impact of this pain. However, research is needed to identify psychosocial processes to target through such treatments. The current systematic review and meta-analysis examined the evidence for psychosocial factors associated with pain, disability, and quality of life in people living with HIV and persistent pain. Observational and experimental studies reporting on the association between one or more psychosocial factors and one or more pain-...
Source: Pain - November 20, 2018 Category: Anesthesiology Tags: Systematic Reviews and Meta-Analyses Source Type: research

Catastrophizing, pain, and functional outcomes for children with chronic pain: a meta-analytic review
This study aimed to: (1) meta-analytically quantify the relationship between catastrophizing and pain and functional/psychosocial outcomes (functional disability/physical functioning, anxiety, depression, and QOL) in children with chronic pain, and (2) examine potential moderators of these relationships. Using a random-effects model, a total of 111 effect sizes from 38 studies were analyzed. Effect sizes ranged from medium to large, with anxiety, depression, and QOL demonstrating a strong association with catastrophizing. Pain intensity and physical disability had a moderate association with catastrophizing. These relation...
Source: Pain - November 20, 2018 Category: Anesthesiology Tags: Systematic Reviews and Meta-Analyses Source Type: research

Why wait to address high-risk cases of acute low back pain? A comparison of stepped, stratified, and matched care
No abstract available (Source: Pain)
Source: Pain - November 20, 2018 Category: Anesthesiology Tags: Topical Review Source Type: research

When pain gets stuck: the evolution of pain chronification and treatment resistance
It is well-recognized that, despite similar pain characteristics, some people with chronic pain recover, whereas others do not. In this review, we discuss possible contributions and interactions of biological, social, and psychological perturbations that underlie the evolution of treatment-resistant chronic pain. Behavior and brain are intimately implicated in the production and maintenance of perception. Our understandings of potential mechanisms that produce or exacerbate persistent pain remain relatively unclear. We provide an overview of these interactions and how differences in relative contribution of dimensions such...
Source: Pain - November 20, 2018 Category: Anesthesiology Tags: Comprehensive Review Source Type: research

Why do some people develop chronic, treatment-resistant pain and not others?
No abstract available (Source: Pain)
Source: Pain - November 20, 2018 Category: Anesthesiology Tags: Commentary Source Type: research

Reply
No abstract available (Source: Pain)
Source: Pain - October 25, 2018 Category: Anesthesiology Tags: Correspondence Source Type: research

Quantitative sensory testing in migraine patients must be phase-specific
No abstract available (Source: Pain)
Source: Pain - October 25, 2018 Category: Anesthesiology Tags: Correspondence Source Type: research

Long-term changes in biopsychosocial characteristics related to temporomandibular disorder: findings from the OPPERA study
Painful temporomandibular disorders (TMDs) are both consequence and cause of change in multiple clinical, psychosocial, and biological factors. Although longitudinal studies have identified antecedent biopsychosocial factors that increase risk of the TMD onset and persistence, little is known about long-term change in those factors after TMD develops or remits. During a 7.6-year median follow-up period, we measured change in psychosocial characteristics, pain sensitivity, cardiovascular indicators of autonomic function, and clinical jaw function among 189 participants whose baseline chronic TMD status either persisted or r...
Source: Pain - October 25, 2018 Category: Anesthesiology Tags: Research Paper Source Type: research

Prevalence of chronic pain with or without neuropathic characteristics in France using the capture–recapture method: a population-based study
This study sought to provide up-to-date estimates of the prevalence of people experiencing CP ± neuropathic characteristics in France using the capture–recapture method. In 2013 to 2015, 3 data sources were used: the French prescription drug database (D-list), the national hospital discharge database (H-list), and the French pain center database (P-list). Patients aged 18 years and older treated with analgesic drugs for ≥6 months (D-list) or with a diagnosis of CP ± neuropathic characteristics (H- and P-lists) were included. Two successive capture–recapture analyses were conducted, with log-lin...
Source: Pain - October 25, 2018 Category: Anesthesiology Tags: Research Paper Source Type: research

Inflammation induces Epac-protein kinase C alpha and epsilon signaling in TRPV1-mediated hyperalgesia
The exchange proteins activated by cAMP (Epacs) have been shown to play important roles in producing inflammation-induced nociception. Transient receptor potential vanilloid type 1 (TRPV1) is a major receptor processing thermal and chemosensitive nociceptive information. The role of Epacs in modulating the activity of TRPV1 has yet to be determined. Studying the effect of complete Freund adjuvant (CFA)-induced inflammation on capsaicin-activated TRPV1 nociceptive responses in dorsal root ganglia (DRG), we found that CFA produced a large increase in capsaicin-induced responses. The increase was inhibited by Epac1 and Epac2 ...
Source: Pain - October 25, 2018 Category: Anesthesiology Tags: Research Paper Source Type: research

Quantifying visual allodynia across migraine subtypes: the Leiden Visual Sensitivity Scale
Enhanced sensitivity to light (photophobia) and patterns is common in migraine and can be regarded as visual allodynia. We aimed to develop and validate a questionnaire to easily quantify sensitivity to light and patterns in large populations, and to assess and compare visual allodynia across different migraine subtypes and states. We developed the Leiden Visual Sensitivity Scale (L-VISS), a 9-item scale (score range 0-36 points), based on literature and patient interviews, and examined its construct validity. Furthermore, we assessed ictal and interictal visual sensitivity in episodic migraine with (n = 67) and without (n...
Source: Pain - October 25, 2018 Category: Anesthesiology Tags: Research Paper Source Type: research

Contextual influences in decoding pain expressions: effects of patient age, informational priming, and observer characteristics
We aimed to examine the effects of contextual factors (ie, observers' training background and priming texts) on decoding facial pain expressions of younger and older adults. A total of 165 participants (82 nursing students and 83 nonhealth professionals) were randomly assigned to one of 3 priming conditions: (1) information about the possibility of secondary gain (misuse); (2) information about the frequency and undertreatment of pain in the older adult (undertreatment); or (3) neutral information (control). Subsequently, participants viewed 8 videos of older adults and 8 videos of younger adults undergoing a discomforting...
Source: Pain - October 25, 2018 Category: Anesthesiology Tags: Research Paper Source Type: research

Isolated nociceptors reveal multiple specializations for generating irregular ongoing activity associated with ongoing pain
Ongoing pain has been linked to ongoing activity (OA) in human C-fiber nociceptors, but rodent models of pain-related OA have concentrated on allodynia rather than ongoing pain, and on OA generated in non-nociceptive Aβ fibers rather than C-fiber nociceptors. Little is known about how ongoing pain or nociceptor OA is generated. To define neurophysiological alterations underlying nociceptor OA, we have used isolated dorsal root ganglion neurons that continue to generate OA after removal from animals displaying ongoing pain. We subclassify OA as either spontaneous activity generated solely by alterations intrinsic to th...
Source: Pain - October 25, 2018 Category: Anesthesiology Tags: Research Paper Source Type: research

Neuropathic pain clinical trials: factors associated with decreases in estimated drug efficacy
This study is a secondary analysis of data from a previous published NeuPSIG systematic review and meta-analysis, updated to include studies published up till March 2017. We included double-blind, randomized, placebo-controlled trials examining the effect of drugs for which we had made strong or weak recommendations for use in neuropathic pain in the previously published review. As the primary outcome, we used an aggregated number needed to treat for 50% pain reduction (alternatively 30% pain reduction or moderate pain relief). Analyses involved 128 trials. Number needed to treat values increased from around 2 to 4 in tria...
Source: Pain - October 25, 2018 Category: Anesthesiology Tags: Research Paper Source Type: research

Aδ and not C fibers mediate thermal hyperalgesia to short laser stimuli after burn injury in man
It remains unclear which nerve fibers are responsible for mediating hyperalgesia after skin injury. Here, we examined the role of Aδ and C fibers in inflammatory hyperalgesia after a first-degree burn injury. A CO2 laser delivered ultrafast short constant-temperature heat pulses to the upper part of the lower leg to stimulate selectively the relatively fast-conducting thinly myelinated Aδ and the slowly conducting unmyelinated C fibers. Participants were asked to respond as fast as possible whenever they detected a thermal stimulus. Thresholds and reaction times to selective Aδ and C fiber activations wer...
Source: Pain - October 25, 2018 Category: Anesthesiology Tags: Research Paper Source Type: research

Electrophysiological characterisation of central sensitisation in canine spontaneous osteoarthritis
In man, central sensitisation (CS) contributes to the pain of osteoarthritis (OA). Dogs with spontaneous OA may also exhibit CS. Electrophysiological reflex measurements are more objective than behavioural assessments and can be used to evaluate CS in preclinical and clinical studies. It was hypothesised that dogs suffering from OA would exhibit electrophysiological characteristics indicative of CS, associated with reduced diffuse noxious inhibitory controls (DNICs). One hundred and seventeen client-owned dogs were recruited to the study. Hind limb nociceptive withdrawal reflex thresholds, stimulus response, and temporal s...
Source: Pain - October 25, 2018 Category: Anesthesiology Tags: Research Paper Source Type: research

Peripherally administered calcitonin gene–related peptide induces spontaneous pain in mice: implications for migraine
In this study, we report that peripherally administered CGRP can act in a light-independent manner to produce spontaneous pain in mice that is manifested as a facial grimace. As an objective validation of the orbital tightening action unit of the grimace response, we developed a squint assay using a video-based measurement of the eyelid fissure, which confirmed a significant squint response after CGRP injection, both in complete darkness and very bright light. These indicators of discomfort were completely blocked by preadministration of a monoclonal anti-CGRP–blocking antibody. However, the nonsteroidal anti-inflamm...
Source: Pain - October 25, 2018 Category: Anesthesiology Tags: Research Paper Source Type: research

Complex regional pain syndrome: intradermal injection of phenylephrine evokes pain and hyperalgesia in a subgroup of patients with upregulated α1-adrenoceptors on dermal nerves
The aim of this study was to determine whether upregulated cutaneous expression of α1-adrenoceptors (α1-AR) is a source of pain in patients with complex regional pain syndrome (CRPS). Immunohistochemistry was used to identify α1-AR on nerve fibres and other targets in the affected and contralateral skin of 90 patients, and in skin samples from 38 pain-free controls. The distribution of α1-AR was compared between patients and controls, and among subgroups of patients defined by CRPS duration, limb temperature asymmetry, and diagnostic subtype (CRPS I vs CRPS II). In addition, α1-AR expression w...
Source: Pain - October 25, 2018 Category: Anesthesiology Tags: Research Paper Source Type: research

Anti–nerve growth factor does not change physical activity in normal young or aging mice but does increase activity in mice with skeletal pain
Anti–nerve growth factor (anti-NGF) therapy has shown significant promise in attenuating several types of skeletal pain. However, whether anti-NGF therapy changes the level of physical activity in individuals with or without skeletal pain is largely unknown. Here, automated day/night activity boxes monitored the effects of anti-NGF treatment on physical activity in normal young (3 months old) and aging (18-23 months old) mice and mice with bone fracture pain. Although aging mice were clearly less active and showed loss of bone mass compared with young mice, anti-NGF treatment had no effect on any measure of day/night...
Source: Pain - October 25, 2018 Category: Anesthesiology Tags: Research Paper Source Type: research

Analgesic effects of a novel pH-dependent μ-opioid receptor agonist in models of neuropathic and abdominal pain
Recently, (±)-N-(3-fluoro-1-phenethylpiperidine-4-yl)-N-phenyl propionamide (NFEPP), a newly designed μ-opioid receptor (MOR) agonist with a low pKa, has been shown to produce injury-restricted analgesia in models of inflammatory and postoperative pain, without exhibiting typical opioid side effects. Here, we investigated MOR binding of NFEPP in brain and dorsal root ganglia, pH in injured tissues, and the analgesic efficacy of NFEPP compared with fentanyl in a chronic constriction injury model of neuropathic pain, and in the acetic acid–induced abdominal writhing assay in rats. Binding experiments revealed...
Source: Pain - October 25, 2018 Category: Anesthesiology Tags: Research Paper Source Type: research

Dynamic pain connectome functional connectivity and oscillations reflect multiple sclerosis pain
Pain is a prevalent and debilitating symptom of multiple sclerosis (MS); yet, the mechanisms underlying this pain are unknown. Previous studies have found that the functional relationships between the salience network (SN), specifically the right temporoparietal junction a SN node, and other components of the dynamic pain connectome (default mode network [DMN], ascending and descending pathways) are abnormal in many chronic pain conditions. Here, we use resting-state functional magnetic resonance imaging and measures of static and dynamic functional connectivity (sFC and dFC), and regional BOLD variability to test the hypo...
Source: Pain - October 25, 2018 Category: Anesthesiology Tags: Research Paper Source Type: research

Lionfish venom elicits pain predominantly through the activation of nonpeptidergic nociceptors
In this study, we provide the first characterization of the pain and inflammation caused by lionfish venom and examine the mechanisms through which it causes pain using a combination of in vivo and in vitro approaches including behavioral, physiological, calcium imaging, and electrophysiological testing. Intraplantar injections of the venom produce a significant increase in pain behavior, as well as a marked increase in mechanical sensitivity for up to 24 hours after injection. The algogenic substance(s) are heat-labile peptides that cause neurogenic inflammation at the site of injection and induction of Fos and microglia ...
Source: Pain - October 25, 2018 Category: Anesthesiology Tags: Research Paper Source Type: research

Evaluation of composite responder outcomes of pain intensity and physical function in neuropathic pain clinical trials: an ACTTION individual patient data analysis
Integrating information on physical function and pain intensity into a composite measure may provide a useful method for assessing treatment efficacy in clinical trials of chronic pain. Accordingly, we evaluated composite outcomes in trials of duloxetine, gabapentin, and pregabalin. Data on 2287 patients in 9 trials for painful diabetic peripheral neuropathy (DPN) and 1513 patients in 6 trials for postherpetic neuralgia (PHN) were analyzed. All trials assessed pain intensity on a 0 to 10 numeric rating scale and physical function with the 10-item subscale of the Short Form-36, ranging 0 to 100 with higher scores indicating...
Source: Pain - October 25, 2018 Category: Anesthesiology Tags: Research Paper Source Type: research

Estimating relative efficacy in acute postoperative pain: network meta-analysis is consistent with indirect comparison to placebo alone
Network meta-analysis uses direct comparisons of interventions within randomized controlled trials and indirect comparisons across them. Network meta-analysis uses more data than a series of direct comparisons with placebo, and theoretically should produce more reliable results. We used a Cochrane overview review of acute postoperative pain trials and other systematic reviews to provide data to test this hypothesis. Some 261 trials published between 1966 and 2016 included 39,753 patients examining 52 active drug and dose combinations (27,726 given active drug and 12,027 placebo), in any type of surgery (72% dental). Most t...
Source: Pain - October 25, 2018 Category: Anesthesiology Tags: Research Paper Source Type: research

Efficacy of adding interoceptive exposure to intensive interdisciplinary treatment for adolescents with chronic pain: a randomized controlled trial
In conclusion, the results suggest that IE is not particularly effective for all the pediatric chronic pain patients, but the patients with high fear of pain before treatment and with abdominal pain strongly benefit from this intervention. (Source: Pain)
Source: Pain - October 25, 2018 Category: Anesthesiology Tags: Research Paper Source Type: research

Low- and high-threshold primary afferent inputs to spinal lamina III antenna-type neurons
The dorsal horn of the spinal cord (laminae I-VI) processes diverse modalities of nociceptive and nonnociceptive sensory information. Antenna-type neurons with cell bodies located in lamina III and large dendritic trees extending from the superficial lamina I to deep lamina IV are best shaped for the integration of a wide variety of inputs arising from primary afferent fibers and intrinsic spinal circuitries. Although the somatodendritic morphology, the hallmark of antenna neurons, has been well studied, little is still known about the axon structure and basic physiological properties of these cells. Here, we did whole-cel...
Source: Pain - October 25, 2018 Category: Anesthesiology Tags: Research Paper Source Type: research

Chronic itch impairs mood and HPA axis function in mice: modulation by CRFR1 antagonist
Chronic itch is clinically correlated with the development of mood disorders such as anxiety and depression. Nonetheless, whether this relevance exists in rodents is unknown, and evidence demonstrating chronic itch can affect mood is lacking. The aim of this study is to characterize the affective consequences of chronic itch, and explore potential mechanisms and interventional strategy. We subjected mice to chronic itch by repetitive cutaneous treatment with acetone and diethylether followed by water (AEW) that models “dry skin.” After 3 to 4 weeks AEW treatment, the mice developed behavioral phenotypes of anxi...
Source: Pain - October 25, 2018 Category: Anesthesiology Tags: Research Paper Source Type: research