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Pain Perception (pain + perception)
Kinds of Pain Perception Selected AbstractsRESEARCH INTO PAIN PERCEPTION WITH ARTERIOVENOUS FISTULA (AVF) CANNULATIONJOURNAL OF RENAL CARE, Issue 4 2008Ana E. Figueiredo RN SUMMARY Patients with end-stage renal failure (ESRF) undergoing haemodialysis (HD) are repeatedly exposed to stress and pain from approximately 300 punctures per year to their arteriovenous fistula (AVF). Repeated AVF punctures lead to a considerable degree of pain, due to the calibre and length of the bevel of fistula needles. Pain is a sensitive, emotional and subjective experience. The objective of this study was to measure pain associated with AVF needling. The analogue visual scale (AVS) divided into 10 equal parts (0 indicating lack of pain, and 10 unbearable pain) was used. Patients7 perceptions were measured in three different HD sessions. Pain was considered mild during AVF needling. The buttonhole technique caused a mean degree of pain of 2.4 (±1.7), compared to 3.1 (±2.3) using the conventional ropeladder technique. Although without reaching a statistically significant difference, diminished pain was associated with the buttonhole technique. [source] Defibrillation Efficacy and Pain Perception of Two Biphasic Waveforms for Internal Cardioversion of Atrial FibrillationJOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 8 2003Jens Jung M.D. Introduction: We evaluated the influence of the peak voltage of waveforms used for internal cardioversion of atrial fibrillation on defibrillation efficacy and pain perception. A low peak voltage biphasic waveform generated by a 500-,F capacitor with 40% tilt was compared to a standard biphasic waveform generated by a 60-,F capacitor with 80% tilt. Methods and Results: In 19 patients with paroxysmal atrial fibrillation (79% male, age 55 ± 11 years, 21% with heart disease), the atrial defibrillation threshold (ADFT) was determined during deep sedation with midazolam for both waveforms in a randomized fashion using a step-up protocol. Internal cardioversion with a single lead (shock vector: coronary sinus to right atrium) was successful in 18 (95%) of 19 patients. ADFT energy and peak voltage were significantly lower for the low-voltage waveform (2.1 ± 2.4 J vs 3.5 ± 3.9 J, P < 0.01; 100 ± 53 V vs 290 ± 149 V, P < 0.01). Sedation then was reversed with flumazenil after ADFT testing. Two shocks at the ADFT (or a 3-J shock if ADFT >3 J) were administered to the patient using each waveform in random order. Pain perception was assessed using both a visual scale and a numerical score. ADFTs were above the pain threshold in 17 (94%) of 18 patients, even though the ADFT with the 500-,F waveform was <100 V in 63% of the patients. Pain perception was comparable for both waveforms (numerical score: 6.5 ± 2.4 vs 6.3 ± 2.6; visual scale: 5.4 ± 2.6 vs 5.2 ± 3.1; P = NS, 500-,F vs 60-,F). The second shock was perceived as more painful in 88% of the patients, independent of the waveform used. Conclusion: Despite a 66% lower peak voltage and a 40% lower energy, the 40% tilt, 500-,F capacitor biphasic waveform did not change the pain perceived by the patient during delivery of internal cardioversion shocks. Pain perception for internal cardioversion probably is not influenced by peak voltage alone and increases with the number of applied shocks. (J Cardiovasc Electrophysiol, Vol. 14, pp. 837-840, August 2003) [source] Role of botulinum toxin in migraine therapyDRUG DEVELOPMENT RESEARCH, Issue 7 2007Wilhelm J. Schulte-Mattler Abstract Botulinum toxin effectively blocks the release of acetylcholine from motor nerve terminals. Thus, botulinum toxin injections are well established in the treatment of disorders in which patients are impaired by involuntary muscle contractions. A remarkable pain reduction was frequently observed in these patients, and in vitro studies showed that botulinum toxin reduces not only the release of acetylcholine, but also the release of neuropeptides involved in pain perception. It was therefore hypothesized that botulinum toxin may help patients with pain not caused by muscular contractions, such as migraine or chronic daily headache, which includes chronic migraine. So far, the results of randomized, double-blind, placebo controlled trials on botulinum toxin in a total of 2,612 patients with migraine or with chronic daily headache were published. A superiority of botulinum toxin compared with placebo injections could not clearly be confirmed in any of the studies. One hypothesis derived from these results was that subgroups of patients with migraine can be defined in whom botulinum toxin may be efficacious. This hypothesis awaits confirmation. Interestingly, the efficacy of both botulinum toxin and placebo injections was found to be significant and similar to the efficacy of established oral migraine treatment. This finding may help explain the enthusiasm that followed the first open-label use of botulinum in patients with migraine. Drug Dev Res 68:397,402, 2007. © 2008 Wiley-Liss, Inc. [source] PRECLINICAL STUDY: Is withdrawal hyperalgesia in morphine-dependent mice a direct effect of a low concentration of the residual drug?ADDICTION BIOLOGY, Issue 4 2009Vardit Rubovitch ABSTRACT Withdrawal of opioid drugs leads to a cluster of unpleasant symptoms in dependent subjects. These symptoms are stimulatory in nature and oppose the acute, inhibitory effects of opiates. The conventional theory that explains the opioid withdrawal syndrome assumes that chronic usage of opioid drugs activates compensatory mechanisms whose stimulatory effects are revealed upon elimination of the inhibitory opioid drug from the body. Based on previous studies that show a dose-dependent dual activity of opiates, including pain perception, we present here an alternative explanation to the phenomenon of withdrawal-induced hyperalgesia. According to this explanation, the residual low concentration of the drug that remains after cessation of its administration elicits the stimulatory withdrawal hyperalgesia. The goal of the present study was to test this hypothesis. In the present study we rendered mice dependent on morphine by a daily administration of the drug. Cessation of morphine application elicited withdrawal hyperalgesia that was completely blocked by a high dose of the opiate antagonist naloxone (100 mg/kg). Similarly, naloxone (2 mg/kg)-induced withdrawal hyperalgesia was also blocked by 100 mg/kg of naloxone. The blockage of withdrawal hyperalgesia by naloxone suggested the involvement of opioid receptors in the phenomenon and indicated that withdrawal hyperalgesia is a direct effect of a residual, low concentration of morphine. Acute experiments that show morphine- and naloxone-induced hyperalgesia further verified our hypothesis. Our findings offer a novel, alternative approach to opiate detoxifications that may prevent withdrawal symptoms by a complete blockage of the opioid receptors using a high dose of the opioid antagonist. [source] Effect of gender on acute pain prediction and memory in periodontal surgeryEUROPEAN JOURNAL OF ORAL SCIENCES, Issue 2 2000Ilana Eli Pain is a complex experience that is affected by factors such as gender, stress, anxiety and cognitions. The purpose of this study was to investigate the inter-relationship between gender and acute pain prediction and memory under periodontal surgery treatment. The study was conducted on 15 male and 22 female dental patients (mean age 34 yr, mean education level 14.7 yr), who were scheduled for periodontal surgery. Patients were evaluated during four consecutive appointments: at initial check-up, immediately pre-operatively, 1 wk post-operatively, and at 4 wk post-operative follow-up. Patients were requested to complete questionnaires concerning their anxiety at each appointment and to indicate their subjective evaluations concerning pain (on a visual analogue scale). Evaluations concerning expectation to experience pain during the planned surgery (pain prediction) were made at the first two appointments and evaluations of the experienced pain as remembered from the surgery (pain memory) were made at the last two appointments. Gender had a significant effect on pain prediction and pain memory. Men expected to experience more pain pre-operatively than women but remembered less pain post-operatively. It was concluded that cognitive pain perception in clinical situations differs between genders. [source] The human skin/chick chorioallantoic membrane model accurately predicts the potency of cosmetic allergensEXPERIMENTAL DERMATOLOGY, Issue 4 2009Dan Slodownik Abstract:, The current standard method for predicting contact allergenicity is the murine local lymph node assay (LLNA). Public objection to the use of animals in testing of cosmetics makes the development of a system that does not use sentient animals highly desirable. The chorioallantoic membrane (CAM) of the chick egg has been extensively used for the growth of normal and transformed mammalian tissues. The CAM is not innervated, and embryos are sacrificed before the development of pain perception. The aim of this study was to determine whether the sensitization phase of contact dermatitis to known cosmetic allergens can be quantified using CAM-engrafted human skin and how these results compare with published EC3 data obtained with the LLNA. We studied six common molecules used in allergen testing and quantified migration of epidermal Langerhans cells (LC) as a measure of their allergic potency. All agents with known allergic potential induced statistically significant migration of LC. The data obtained correlated well with published data for these allergens generated using the LLNA test. The human-skin CAM model therefore has great potential as an inexpensive, non-radioactive, in vivo alternative to the LLNA, which does not require the use of sentient animals. In addition, this system has the advantage of testing the allergic response of human, rather than animal skin. [source] Mutations in human monoamine-related neurotransmitter pathway genes,HUMAN MUTATION, Issue 7 2008Jan Haavik Abstract Biosynthesis and metabolism of serotonin and catecholamines involve at least eight individual enzymes that are mainly expressed in tissues derived from the neuroectoderm, e.g., the central nervous system (CNS), pineal gland, adrenal medulla, enterochromaffin tissue, sympathetic nerves, and ganglia. Some of the enzymes appear to have additional biological functions and are also expressed in the heart and various other internal organs. The biosynthetic enzymes are tyrosine hydroxylase (TH), tryptophan hydroxylases type 1 and 2 (TPH1, TPH2), aromatic amino acid decarboxylase (AADC), dopamine beta-hydroxylase (D,H), and phenylethanolamine N -methyltransferase (PNMT), and the specific catabolic enzymes are monoamine oxidase A (MAO-A) and catechol O -methyltransferase (COMT). For the TH, DDC, DBH, and MAOA genes, many single nucleotide polymorphisms (SNPs) with unknown function, and small but increasing numbers of cases with autosomal recessive mutations have been recognized. For the remaining genes (TPH1, TPH2, PNMT, and COMT) several different genetic markers have been suggested to be associated with regulation of mood, pain perception, and aggression, as well as psychiatric disturbances such as schizophrenia, depression, suicidality, and attention deficit/hyperactivity disorder. The genetic markers may either have a functional role of their own, or be closely linked to other unknown functional variants. In the future, molecular testing may become important for the diagnosis of such conditions. Here we present an overview on mutations and polymorphisms in the group of genes encoding monoamine neurotransmitter metabolizing enzymes. At the same time we propose a unified nomenclature for the nucleic acid aberrations in these genes. New variations or details on mutations will be updated in the Pediatric Neurotransmitter Disorder Data Base (PNDDB) database (www.bioPKU.org). Hum Mutat 29(7), 891,902, 2008. © 2008 Wiley-Liss, Inc. [source] Defibrillation Efficacy and Pain Perception of Two Biphasic Waveforms for Internal Cardioversion of Atrial FibrillationJOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 8 2003Jens Jung M.D. Introduction: We evaluated the influence of the peak voltage of waveforms used for internal cardioversion of atrial fibrillation on defibrillation efficacy and pain perception. A low peak voltage biphasic waveform generated by a 500-,F capacitor with 40% tilt was compared to a standard biphasic waveform generated by a 60-,F capacitor with 80% tilt. Methods and Results: In 19 patients with paroxysmal atrial fibrillation (79% male, age 55 ± 11 years, 21% with heart disease), the atrial defibrillation threshold (ADFT) was determined during deep sedation with midazolam for both waveforms in a randomized fashion using a step-up protocol. Internal cardioversion with a single lead (shock vector: coronary sinus to right atrium) was successful in 18 (95%) of 19 patients. ADFT energy and peak voltage were significantly lower for the low-voltage waveform (2.1 ± 2.4 J vs 3.5 ± 3.9 J, P < 0.01; 100 ± 53 V vs 290 ± 149 V, P < 0.01). Sedation then was reversed with flumazenil after ADFT testing. Two shocks at the ADFT (or a 3-J shock if ADFT >3 J) were administered to the patient using each waveform in random order. Pain perception was assessed using both a visual scale and a numerical score. ADFTs were above the pain threshold in 17 (94%) of 18 patients, even though the ADFT with the 500-,F waveform was <100 V in 63% of the patients. Pain perception was comparable for both waveforms (numerical score: 6.5 ± 2.4 vs 6.3 ± 2.6; visual scale: 5.4 ± 2.6 vs 5.2 ± 3.1; P = NS, 500-,F vs 60-,F). The second shock was perceived as more painful in 88% of the patients, independent of the waveform used. Conclusion: Despite a 66% lower peak voltage and a 40% lower energy, the 40% tilt, 500-,F capacitor biphasic waveform did not change the pain perceived by the patient during delivery of internal cardioversion shocks. Pain perception for internal cardioversion probably is not influenced by peak voltage alone and increases with the number of applied shocks. (J Cardiovasc Electrophysiol, Vol. 14, pp. 837-840, August 2003) [source] Relationships between partner's support during labour and maternal outcomesJOURNAL OF CLINICAL NURSING, Issue 2 2000MPhil, Wan Yim Ip BN ,,The objective of this study was to measure the relationship between women's ratings of partners' participation during labour and maternal outcomes as measured by anxiety level, pain perception, dosage of pain-relieving drug used and length of labour. ,,A convenience sample of 45 primigravid women was selected from the postpartum unit of a public hospital in Hong Kong. They were all first-time Chinese mothers, aged 18 or over, who had attended antenatal classes and had their partners present during labour. ,,The State Scale of the State-Trait Anxiety Inventory was used to measure maternal anxiety during labour. Labour pain was measured by the Visual Analogue Scale. A series of scales were developed to measure partners' participation during labour. ,,Women's ratings of partners' practical support were significantly lower than their ratings of partners' emotional support. There were no significant associations between level of emotional support and maternal outcome measures. However, perceived practical support was positively related to the dosage of pain-relieving drug used and total length of labour. Positive relationships between the duration of partners' presence and women's ratings of perceived support provided by partners during labour were also found. [source] Cannabinoid,vanilloid receptor interactions in pain signalingJOURNAL OF NEUROCHEMISTRY, Issue 2003V. Di Marzo Agents that activate cannabinoid CB1 receptors for marijuana's active principal, THC, or vanilloid VR1 receptors for red chilli peppers' pungent ingredient, capsaicin, modulate pain perception. Stimulation of presynaptic CB1 leads to inhibition of glutamate release in the spinal cord, whereas VR1 stimulation causes release of substance P and CGRP from DRG neurons. VR1 undergoes rapid desensitization by its agonists, which makes VR1-expressing neurons insensitive to subsequent stimulation and results in analgesia. Thus, both CB1 and VR1, which are coexpressed in several spinal and DRG neurons, are targets for analgesic drug development. CB1 and VR1 also share endogenous agonists, namely anandamide, NADA and some of their analogs, and may be regarded as metabotropic and ionotropic receptors for the same family of mediators, with opposing roles in pain perception. The development of ,hybrid' CB1/VR1 agonists as potent analgesics and the functional relationships between CB1 and VR1 in sensory neurons will be discussed. [source] Endocannabinoids, a novel target in pain treatmentJOURNAL OF NEUROCHEMISTRY, Issue 2003S. C. Azad Cannabinoids display a variety of central effects including analgesia, control of spasticity and influence of emotional states. Activation of the brain-type cannabinoid receptor CB1 inhibits the adenylyl cyclase-protein kinase A-pathway and modulates calcium and potassium conductances. CB1 is widely distributed throughout the central nervous system. Among other brain regions, CB1 is highly expressed in the amygdala, which is important for the control of emotional behavior including anxiety and pain perception. In a recent investigation using auditory fear-conditioning tests, we showed that the endogenous cannabinoid system in the amygdala is crucially involved in the extinction of aversive memories. Using electrophysiological techniques, we also found that endogenous and exogenously applied cannabinoids play a major role in the modulation of both, synaptic transmission and plasticity in this brain region. Our behavioral and electrophysiological results indicate that the endogenous cannabinoid system may represent a novel target in the treatment of chronic pain. [source] The effect of tooth clenching on the sensory and pain perception in the oro-facial region of symptom-free men and womenJOURNAL OF ORAL REHABILITATION, Issue 7 2009I. OKAYASU Summary, The aim of this study was (i) to examine the effect of light tooth contact as in diurnal tooth clenching on the tactile detection threshold (TDT), the filament-prick pain detection threshold (FPT) and the pressure pain threshold (PPT) in the oro-facial region and (ii) to examine the possible gender difference in this effect on the tactile and pain perception. Twenty healthy volunteers participated. The TDT and the FPT were measured by means of Semmes-Weinstein monofilaments, on the cheek skin (CS) overlying the masseter muscles (MM) and on the skin overlying the palm side of the thenar skin (TS). The PPT was measured at the central part of the MM using a pressure algometer. Each parameter was measured before and after keeping light tooth contact for 5 min (session 1) and after keeping the jaw relaxed for 5 min (session 2) as a control. Although there were no significant session effects on any of the parameters, there were significant effects of experimental condition on the TDT in both men and women (P < 0·001). Men had a significant higher FPT of the left CS (P < 0·05) and TS (P < 0·01) and a significant higher PPT of the MM than women (P < 0·001). These results illustrate that sensitivity to pain (FPT, PPT) was higher in women than in men. Although there were no significant gender differences in habituation of sensory perception, the increase of TDT after clenching/no clenching was larger in women, which warrants further study. [source] Role of spinal cord glia in the central processing of peripheral pain perceptionNEUROGASTROENTEROLOGY & MOTILITY, Issue 5 2010S. Bradesi Abstract Background, The discovery that glial activation plays a critical role in the modulation of neuronal functions and affects the spinal processing of nociceptive signalling has brought new understanding on the mechanisms underlying central sensitization involved in chronic pain facilitation. Spinal glial activation is now considered an important component in the development and maintenance of allodynia and hyperalgesia in various models of chronic pain, including neuropathic pain and pain associated with peripheral inflammation. In addition, spinal glial activation is also involved in some forms of visceral hyperalgesia. Purpose, We discuss the signalling pathways engaged in central glial activation, including stress pathways, and the neuron,glia bidirectional relationships involved in the modulation of synaptic activity and pain facilitation. In this expanding field of research, the characterization of the mechanisms by which glia affect spinal neuro-transmission will increase our understanding of central pain facilitation, and has the potential for the development of new therapeutic agents for common chronic pain conditions. [source] A randomized comparison of post-operative pain, quality of life, and physical performance during the first 6 weeks after abdominal or vaginal surgical correction of descensus uteriNEUROUROLOGY AND URODYNAMICS, Issue 4 2005J.P.W.R. Roovers Abstract Aims With respect to urogenital function, vaginal hysterectomy combined with anterior and/or posterior colporraphy has been shown to be superior to abdominal sacrocolpopexy with preservation of the uterus. We performed a randomized trial to compare the effects of both procedures on pain, quality of life and physical performance during the first six weeks after surgery. Methods Eighty-two patients were randomized to have surgery either by vaginal or abdominal approach. All patients were asked to complete the RAND-36 before surgery and 6 weeks after surgery and to keep a diary for the first 6 weeks after surgery. This diary assessed the pain perception and use of pain medication, bother of limitations due to the surgery and performance of daily activities after surgery. These outcomes were compared. Results All patients completed the RAND-36 and 68 patients completed the diary. Patients who had undergone abdominal surgery had a statistically lower score on the health change domain (56 vs 68), bodily pain domain (63 vs 80) and mental health domain (74 vs 81) of the RAND-36, as compared to patients who had undergone vaginal prolapse surgery. During hospital stay, the abdominal group experienced on average more days of pain (4.5 vs 3.0) and impaired mobility (3.7 vs 2.9) as compared to the vaginal group. Patients received more pain medication following abdominal surgery as compared to vaginal surgery. Conclusions The vaginal operation to correct a descensus uteri is associated with less pain, better quality of life and better mobility during the first 6 weeks of the recovery period as compared to the abdominal approach. Neurourol. Urodynam. © 2005 Wiley-Liss, Inc. [source] What Does the Mechanism of Spinal Cord Stimulation Tell Us about Complex Regional Pain Syndrome?PAIN MEDICINE, Issue 8 2010Joshua P. Prager MD Abstract Spinal cord stimulation (SCS) can have dramatic effects on painful, vascular, and motor symptoms of complex regional pain syndrome (CRPS), but its precise mechanism of action is unclear. Better understanding of the physiologic effects of SCS may improve understanding not only of this treatment modality but also of CRPS pathophysiology. Effects of SCS on pain perception are likely to occur through activation of inhibitory GABA-ergic and cholinergic spinal interneurons. Increased release of both neurotransmitters has been demonstrated following SCS in animal models of neuropathic pain, with accompanying reductions in pain behaviors. Effects of SCS on vascular symptoms of CRPS are thought to occur through two main mechanisms: antidromic activation of spinal afferent neurons and inhibition of sympathetic efferents. Cutaneous vasodilation following SCS in animal models has been shown to involve antidromic release of calcitonin gene-related peptide and possibly nitric oxide, from small-diameter sensory neurons expressing the transient receptor potential V1 (TRPV1) receptor. The involvement of sympathetic efferents in the effects of SCS has not been studied in animal models of neuropathic pain, but has been demonstrated in models of angina pectoris. In conclusion, SCS is of clinical benefit in CRPS, and although its mechanism of action merits further elucidation, what little we do know is informative and can partially explain some of the pathophysiology of CRPS. [source] Chronic Pain after Spinal Cord Injury: Results of a Long-Term StudyPAIN MEDICINE, Issue 7 2010Ehsan Modirian MD Abstract Objective., Chronic pain after spinal cord injury (SCI) is a common and considerable complication and may continue for a long time. Design., During a 2-year survey, 13.9 ± 3.0 years after injury, a total of 1,295 war-related spinal cord injury survivors were thoroughly examined by physical and rehabilitation specialists and all relevant data, consisting of type and site of pain as well as exacerbating or palliative factors, were recorded. Patients., The mean age of the survivors was 35.9 ± 7.2; 98.5% were male and 1.5% were female. The level of injury was cervical in 9.3%, thoracic in 67%, and lumbosacral in 23.7%, with 8.1% tetraplegic and 89.1% paraplegic. About 89.8% had complete spinal cord injuries and 10.2% had incomplete spinal cord injuries, based on sensory and motor testing. Results., Spinal cord related pain was reported in 64.9% of the subjects; 8.8% reported a history of pain but had no complaint at the time of examination, and 26.3% had never suffered from any pain. Patients suffering from lumbar spinal cord injury reported the highest percent of pain perception, with pain detected in 83.5% of these patients. Common sites of reported pain were the distal lower extremities (46.5%), proximal lower extremities (40.9%), pelvic girdle (24.5%), and upper limbs (5.7%). Conclusion., Spinal cord injury-related pain interferes with daily activities of patients and significantly influences their quality of life. [source] Nonimmersive Virtual Reality Mirror Visual Feedback Therapy and Its Application for the Treatment of Complex Regional Pain Syndrome: An Open-Label Pilot StudyPAIN MEDICINE, Issue 4 2010Kenji Sato MD Abstract Objective., Chronic pain conditions such as phantom limb pain and complex regional pain syndrome are difficult to treat, and traditional pharmacological treatment and invasive neural block are not always effective. Plasticity in the central nervous system occurs in these conditions and may be associated with pain. Mirror visual feedback therapy aims to restore normal cortical organization and is applied in the treatment of chronic pain conditions. However, not all patients benefit from this treatment. Virtual reality technology is increasingly attracting attention for medical application, including as an analgesic modality. An advanced mirror visual feedback system with virtual reality technology may have increased analgesic efficacy and benefit a wider patient population. In this preliminary work, we developed a virtual reality mirror visual feedback system and applied it to the treatment of complex regional pain syndrome. Design., A small open-label case series. Five patients with complex regional pain syndrome received virtual reality mirror visual feedback therapy once a week for five to eight sessions on an outpatient basis. Patients were monitored for continued medication use and pain intensity. Results., Four of the five patients showed >50% reduction in pain intensity. Two of these patients ended their visits to our pain clinic after five sessions. Conclusion., Our results indicate that virtual reality mirror visual feedback therapy is a promising alternative treatment for complex regional pain syndrome. Further studies are necessary before concluding that analgesia provided from virtual reality mirror visual feedback therapy is the result of reversing maladaptive changes in pain perception. [source] Modulatory Effects of Transcranial Direct Current Stimulation on Laser-Evoked PotentialsPAIN MEDICINE, Issue 1 2009Gabor Csifcsak MD ABSTRACT Objective., Invasive stimulation of the motor cortex has been used for years to alleviate chronic intractable pain in humans. In our study, we have investigated the effect of transcranial direct current stimulation (tDCS), a noninvasive stimulation method, for manipulating the excitability of cortical motor areas on laser evoked potentials (LEP) and acute pain perception. Designs and Settings., The amplitude of the N1, N2, and P2 LEP components of 10 healthy volunteers were evaluated prior to and following anodal, cathodal, and sham stimulation of the primary motor cortex. In a separate experiment subjective, pain rating scores of 16 healthy subjects in two perceptual categories (warm sensation, mild pain) were also analyzed. Results., Cathodal tDCS significantly reduced the amplitude of N2 and P2 components compared with anodal or sham stimulation. However, neither of the tDCS types modified significantly the laser energy values necessary to induce moderate pain. In a separate experiment, cathodal stimulation significantly diminished mild pain sensation only when laser-stimulating the hand contralateral to the side of tDCS, while anodal stimulation modified warm sensation. Conclusions., The possible underlying mechanisms of our findings in view of recent neuroimaging studies are discussed. To our knowledge this study is the first to demonstrate the mild antinociceptive effect of tDCS over the primary motor cortex in healthy volunteers. [source] The Unequal Burden of Pain: Confronting Racial and Ethnic Disparities in PainPAIN MEDICINE, Issue 3 2003Carmen R. Green MD ABSTRACT context. Pain has significant socioeconomic, health, and quality-of-life implications. Racial- and ethnic-based differences in the pain care experience have been described. Racial and ethnic minorities tend to be undertreated for pain when compared with non-Hispanic Whites. objectives. To provide health care providers, researchers, health care policy analysts, government officials, patients, and the general public with pertinent evidence regarding differences in pain perception, assessment, and treatment for racial and ethnic minorities. Evidence is provided for racial- and ethnic-based differences in pain care across different types of pain (i.e., experimental pain, acute postoperative pain, cancer pain, chronic non-malignant pain) and settings (i.e., emergency department). Pertinent literature on patient, health care provider, and health care system factors that contribute to racial and ethnic disparities in pain treatment are provided. evidence. A selective literature review was performed by experts in pain. The experts developed abstracts with relevant citations on racial and ethnic disparities within their specific areas of expertise. Scientific evidence was given precedence over anecdotal experience. The abstracts were compiled for this manuscript. The draft manuscript was made available to the experts for comment and review prior to submission for publication. conclusions. Consistent with the Institute of Medicine's report on health care disparities, racial and ethnic disparities in pain perception, assessment, and treatment were found in all settings (i.e., postoperative, emergency room) and across all types of pain (i.e., acute, cancer, chronic nonmalignant, and experimental). The literature suggests that the sources of pain disparities among racial and ethnic minorities are complex, involving patient (e.g., patient/health care provider communication, attitudes), health care provider (e.g., decision making), and health care system (e.g., access to pain medication) factors. There is a need for improved training for health care providers and educational interventions for patients. A comprehensive pain research agenda is necessary to address pain disparities among racial and ethnic minorities. [source] Tonic blood pressure modulates the relationship between baroreceptor cardiac reflex sensitivity and cognitive performancePSYCHOPHYSIOLOGY, Issue 5 2009Gustavo A. Reyes Del Paso Abstract This study explored the effects of tonic blood pressure on the association between baroreceptor cardiac reflex sensitivity and cognitive performance. Sixty female participants completed a mental arithmetic task. Baroreceptor reflex sensitivity was assessed using sequence analysis. An interaction was found, indicating that the relationship between baroreceptor reflex sensitivity and cognitive performance is modulated by blood pressure levels. Reflex sensitivity was inversely associated to performance indices in the subgroup of participants with systolic blood pressure above the mean, whereas the association was positive in participants with systolic values below the mean. These results are in accordance with the findings in the field of pain perception and suggest that tonic blood pressure modulates the inhibitory effects of baroreceptor stimulation on high central nervous functions. [source] Chest pain is inversely associated with blood pressure during exercise among individuals being assessed for coronary heart diseasePSYCHOPHYSIOLOGY, Issue 2 2007Blaine Ditto Abstract Acute and chronic increases in blood pressure have been related to decreases in pain perception. This phenomenon has been studied primarily using acute experimental pain stimuli. To extend the literature to naturalistic pain and in particular the problem of silent cardiac ischemia, this study examined the relationship between blood pressure and chest pain during exercise stress testing. Nine hundred seven (425 men, 482 women) individuals undergoing exercise stress testing for diagnosis of possible myocardial ischemia completed the McGill Pain Questionnaire (MPQ) immediately afterward and other questionnaires before and after testing. Blood pressure was measured before, during, and after exercise. Systolic blood pressure at the end of exercise was inversely related to a number of measures of pain such as total score on the MPQ. The relationship could not be explained by individual differences in exercise duration, medication use, sex, or other measured variable. In sum, the inverse relationship between blood pressure and sensitivity to pain that has been observed in other populations in experimental and naturalistic conditions was observed for chest pain during exercise. Blood pressure may contribute to episodes of silent ischemia. [source] Novel peptide from spider venom inhibits P2X3 receptors and inflammatory painANNALS OF NEUROLOGY, Issue 5 2010Eugene V. Grishin PhD P2X3 purinoreceptors expressed in mammalian sensory neurons play a key role in several processes, including pain perception. From the venom of the Central Asian spider Geolycosa sp., we have isolated a novel peptide, named purotoxin-1 (PT1), which is to our knowledge the first natural molecule exerting powerful and selective inhibitory action on P2X3 receptors. PT1 dramatically slows down the removal of desensitization of these receptors. The peptide demonstrates potent antinociceptive properties in animal models of inflammatory pain. ANN NEUROL 2010;67:680,683 [source] Extradural haematoma secondary to brown snake (Pseudonaja species) envenomationAUSTRALIAN VETERINARY JOURNAL, Issue 4 2009RKC Ong A 4-year-old Siberian Husky dog was treated with brown snake antivenom by his regular veterinarian after a witnessed episode of brown snake envenomation. The dog was discharged 5 hours post presentation despite an ongoing coagulopathy. The dog was presented to the emergency centre 2 hours later because the owner believed the dog to be in pain. Initial examination revealed an ambulatory but neurologically normal patient with thoracolumbar pain and laboratory evidence of a coagulopathy. Despite correction of the coagulopathy, the signs progressed to bilateral hind limb paresis after approximately 3 hours of hospitalisation, and continued to deteriorate over the next 56 hours to loss of deep pain perception in the right hind limb. Computed tomography imaging identified the presence of an extradural haematoma which was subsequently removed via a hemilaminectomy. Surgical decompression was successful in treating the spinal compression and the dog recovered with minimal complications. To our knowledge this is the first report of extradural haematoma secondary to coagulopathy induced by brown snake envenomation. [source] Impact of ageing on the antinociceptive effect of reference analgesics in the Lou/c ratBRITISH JOURNAL OF PHARMACOLOGY, Issue 6 2002Didier Jourdan Research on the evolution of experimental pain perception and on the achievement of analgesia with ageing has led so far to contradictory results. This study investigated in the rat the impact of ageing on the antinociceptive effect of reference analgesics, acetaminophen (50, 100, 200, 400 mg kg,1 po), aspirin (50, 100, 200, 400 mg kg,1 sc), clomipramine (5, 10, 20, 40 mg kg,1 sc) and morphine (1.25, 2.5, 5, 10 mg kg,1 sc). Lou/c rats were chosen because they provide a model of healthy ageing and they do not develop obesity with age. Three groups of 40 rats each (mature (4 months), middle-aged (18 months) and old (26 months)), were treated with each drug at 14 days interval. Two tests were used: a thermal test (tail immersion in 48°C water and measurement of reaction latency) and a mechanical test (paw pressure and measurement of struggle threshold). Results confirm the increased mechanical sensitivity to pain and no change in thermal sensitivity for old rats compared to mature and middle-aged animals. They show a marked decrease in the effect of morphine with age and no age-related effect for acetaminophen, aspirin or clomipramine. Plasma levels of morphine and metabolites are not different in the three age groups. It is likely that the influence of age on morphine analgesia is linked mainly to pharmacodynamic rather than pharmacokinetic changes. British Journal of Pharmacology (2002) 137, 813,820. doi:10.1038/sj.bjp.0704944 [source] Loss-of-function mutations in the Nav1.7 gene underlie congenital indifference to pain in multiple human populationsCLINICAL GENETICS, Issue 4 2007YP Goldberg Congenital indifference to pain (CIP) is a rare condition in which patients have severely impaired pain perception, but are otherwise essentially normal. We identified and collected DNA from individuals from nine families of seven different nationalities in which the affected individuals meet the diagnostic criteria for CIP. Using homozygosity mapping and haplotype sharing methods, we narrowed the CIP locus to chromosome 2q24,q31, a region known to contain a cluster of voltage-gated sodium channel genes. From these prioritized candidate sodium channels, we identified 10 mutations in the SCN9A gene encoding the sodium channel protein Nav1.7. The mutations completely co-segregated with the disease phenotype, and nine of these SCN9A mutations resulted in truncation and loss-of-function of the Nav1.7 channel. These genetic data further support the evidence that Nav1.7 plays an essential role in mediating pain in humans, and that SCN9A mutations identified in multiple different populations underlie CIP. [source] Adolescents' Pain Experiences Following Acute Blunt Traumatic Injury: Struggle for Internal ControlJOURNAL FOR SPECIALISTS IN PEDIATRIC NURSING, Issue 4 2007Margie Crandall ISSUES AND PURPOSE.,Although blunt trauma injury is a common cause for adolescent pain, little is known about the experience of pain as perceived by adolescents. DESIGN AND METHOD.,Semistructured interviews were conducted with 13 adolescents following blunt trauma injury. Two age-appropriate valid measures (i.e., Adolescent Pediatric Pain Tool and Temporal Dot Matrix) were incorporated into the interviews to elaborate their pain experiences. Grounded theory method was used to analyze data and build substantive theory. RESULTS.,Adolescents' behavioral and cognitive actions (i.e., "internal control") to manage and endure pain were influenced by their pain perceptions, physical losses, and clinicians' actions. PRACTICE IMPLICATIONS.,Nurses, family members, and peers have a crucial role in alleviating adolescents' distress and pain. [source] | ||||||||||||||||||||||