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Chronic inflammatory pain represents one of the largest subsets of chronic pain diagnoses, which affect nearly a quarter of individuals in the United States and cost nearly $600 billion dollars annually. Chronic pain leads to persistent sensory hypersensitivities, as well as emotional and cognitive disturbances. Evidence suggests that melanocortin 4 receptors (MC4Rs) mediate pain-signaling and pain-like behaviors via actions at various nodes in the pain-neural axis, but the field lacks a complete understanding of the potential role of MC4Rs in chronic inflammatory pain in males and females. The central amygdala (CeA) expresses high quantities of MC4R and receives pain-related information from the periphery, and in vivo CeA manipulations alter nociceptive behavior in pain-naïve and in animals with chronic pain. Here, we tested the hypothesis that MC4Rs in the CeA modulate thermal nociception and mechanical sensitivity, as well as pain avoidance, in male and female Wistar rats, using a model of chronic inflammatory pain (Complete Freud's Adjuvant; CFA). First, we report that CFA produces long-lasting hyperalgesia in adult male and female Wistar rats, and long-lasting pain avoidance in male Wistar rats. Second, we report that MC4R antagonism in the CeA reduces thermal nociception and mechanical sensitivity in male and female Wistar rats treated with CFA. Finally, we report that MC4R antagonism in the CeA reduces pain avoidance in male, and that this effect is not due to drug effects on locomotor activity. Our results indicate that a model of chronic inflammatory pain produces long-lasting increases in pain-like behaviors in adult male and female Wistar rats, and that antagonism of MC4Rs in the CeA reverses those effects.
Learn More >Infrared radiation (IR) is a promising complementary treatment for musculoskeletal conditions and chronic pain. By means of a systematic review, we evaluated the contribution of IR to the management of these ailments. PubMed-MEDLINE, Scopus, and Cochrane Library-Cochrane Central Register of Controlled Trials were systematically searched until 20 December 2021. The literature search yielded 233 relevant records. Following the screening of titles and abstracts, 42 full-texts were evaluated. As per inclusion/exclusion criteria, 13 publications were entered into the qualitative assessment. These studies described the effects of IR in humans: three studies focused on osteoarthritis, four studies on fibromyalgia, and six encompassed a wider range of diseases (ankylosing spondylitis, recovery from sports injuries, myofascial pain syndrome). Based on the findings of our systematic review, we noted a decrease in pain levels, as evaluated by the visual analog scale (VAS), in patients suffering from musculoskeletal disorders treated with IR. In addition, IR use led to a decrease in Fibromyalgia Impact Questionnaire (FiQ) scores in subjects diagnosed with fibromyalgia. Nevertheless, IR has failed to facilitate muscle recovery following athletic injuries.
Learn More >Chronic pain extends from childhood to adulthood for many young people. The transition from pediatric to adult care is a critical, yet understudied, healthcare task facing young adults with chronic pain. The aims of this observational, sequential mixed methods study were to (1) document the healthcare transition status of young adults with chronic pain (Stage 1, quantitative aim), (2) examine young adults' perspectives of barriers and facilitators of healthcare transition (Stage 2, qualitative aim), and (3) integrate findings to construct a theoretical framework of healthcare transition. A cohort was identified with childhood chronic pain and prior care in one of 15 multidisciplinary pediatric pain clinics across the United States and Canada. Approximately 6 years later, 189 young adults (M age = 21.0; age range = 18-24; 81.5% female) from this cohort with continuing chronic pain completed surveys for Stage 1, and a subsample (n = 17) completed qualitative interviews for Stage 2. Quantitative findings demonstrated that young adults may experience lapses in care, with 41.8% indicating they had not transitioned to adult pain services. Qualitative analysis revealed young adults experienced significant barriers (e.g., abrupt departure from pediatric care) as well as facilitators (e.g., acceptance of pain prognosis) of healthcare transition. Quantitative and qualitative findings were integrated to construct a healthcare transition framework for chronic pain, which highlights transition as a complex process involving multiple pathways, outcomes, and stakeholders. Advancements in research and practice are needed to develop transition services to bridge gaps in care and optimize health outcomes for young people with chronic pain. Perspective: This mixed-methods study demonstrated that 41.8% of young adults with chronic pain experience lapses in adult-centered pain care and identified key barriers and facilitators to successful healthcare transition. Findings were integrated to construct the first healthcare transition framework for youth with chronic pain.
Learn More >In this study, a pharmacological approach, together with the paw pressure test, was used to investigate the role of dopamine and its receptors in the peripheral processing of the nociceptive response in mice. Initially, the administration of dopamine (5, 20, and 80 ng/paw) in the hind paw of male Swiss mice (30-40 g) promoted antinociceptive effects in a dose-dependent manner. This was considered a peripheral effect, as it did not produce changes in the nociceptive threshold of the contralateral paw. The D, D, and D dopamine receptor antagonists remoxipride (4 μg/paw), U99194 (16 μg/paw), and L-745,870 (16 μg/paw), respectively, reversed the dopamine-mediated antinociception in mice with PGE-induced hyperalgesia. The D and D dopamine receptor antagonists SKF 83566 (2 μg/paw) and SCH 23390 (1.6 μg/paw), respectively, did not alter dopamine antinociception. In contrast, dopamine at higher doses (0.1, 1, and 10 μg/paw) caused hyperalgesia in the animals, and the D and D receptor antagonists reversed this pronociceptive effect (10 μg/paw), whereas the D receptor antagonist remoxipride did not. Our data suggest that dopamine has a dual effect that depends on the dose, as it causes peripheral antinociceptive effects at small doses via the activation of D-like receptors and nociceptive effects at higher doses via the activation of D-like receptors.
Learn More >Dexketoprofen is an enantiomer of ketoprofen (S+) that belongs to nonsteroidal anti-inflammatory drugs and has analgesic, anti-inflammatory, and antipyretic properties. Dexketoprofen has a stronger effect than ketoprofen, which makes it a readily used preparation. The review aims to find in recent original publications data about dexketoprofen and its comparison with other painkilling medications. The systematic literature review was conducted in November 2021 (2018 onwards). We selected 12 articles from PubMed, Google Scholar, Medline Complete databases. In the last 4 years, there have been many publications that shed a new light on dexketoprofen. The article is a comparative analysis of dexketoprofen's action vs other nonsteroidal anti-inflammatory drugs and the combination of dexketoprofen with tramadol vs paracetamol with tramadol. The findings of the review confirm that dexketoprofen is a very good pain reliever more potent than paracetamol. Dexketoprofen produces similar effects to lidocaine and dexmedetomidine. Complex preparations containing dexketoprofen and tramadol are very effective painkilling tandem and are more effective than tramadol and paracetamol therapy in the treatment of acute pain.
Learn More >Cranial autonomic symptoms (CASs) during migraine attacks are reported to be quite common regardless of ethnicity. In our previous study investigating 373 migraineurs, we found that 42.4% of them had CASs. The patients with CASs more frequently had cutaneous allodynia than did those without CASs, and we speculated that CASs were associated with central sensitization. The present study searched for substantial evidence on the relationship between CASs and central sensitization in migraine patients.
Learn More >Certain constituents in migraine food triggers and non-steroidal anti-inflammatory drugs (NSAIDs) inhibit sulfotransferases (SULTs) that detoxify drugs/chemicals and play role in the metabolism of neurotransmitters. We aimed to dissect SULT1A1 modulation of CSD susceptibility and behavior in an in vivo experimental model using hesperidin, a SULT1A1 inhibitor found in citrus fruits (known migraine triggers) and mefenamic acid (SULT1A1 inhibitor), an NSAID to simulate medication overuse.
Learn More >There is currently an emphasis on the biopsychosocial concept of pain in pain therapy programs. However, the complexity of chronic pain, in particular its importance for those affected by it, can only be insufficiently captured with this concept. This is due to the fact that, to date, one core aspect of the phenomenon chronic pain has only rarely been taken into account: its existential character. Chronic pain can threaten the self-image and the individual's understanding of the world, their wishes and goals in life, and ultimately the entire integrity of those affected. Statements by chronic pain sufferers show that such pain always represents an existential experience and affects the person as a whole. Two aspects make this very clear: the existential despair of the pain on the one hand, as well as questions of meaning and reorientation on the other. Current treatment concepts, however, do not adequately consider the existential character of such challenges. Chronic pain should therefore always be perceived and treated from a holistic perspective. In this context, the aspects of recognizing its uniqueness, helping to express the pain and giving space to the experience are to be given special consideration in order to support chronic pain patients in dealing with their pain.
Learn More >The human ATP- and UTP-activated P2Y receptor (P2YR) is a G protein-coupled receptor involved in several pathophysiological conditions including acute and chronic inflammation, cancer, and pain. Despite its potential as a novel drug target, only few P2YR antagonists have been developed so far, all of which suffer from severe drawbacks. These include (i) high polarity due to one or several negative charges resulting in low oral bioavailability, (ii) metabolic instability and generally poor pharmacokinetic properties, and/or (iii) lack of selectivity, which limits their utility for and studies aimed at target validation. In search of new druglike scaffolds for P2YR antagonists, we employed a structure-based virtual high-throughput screening approach utilizing the complex of a P2YR homology model with one of the most potent and selective orthosteric antagonists described so far, AR-C118925 (). After virtual screening of 3.2 million molecules, 58 compounds were purchased and pharmacologically evaluated. Several novel antagonist scaffolds were discovered, and their binding modes at the human P2YR were analyzed by molecular docking studies. The investigated antagonists likely share a similar binding mode with which includes accommodation of bulky, lipophilic groups in the putative orthosteric binding site of the P2YR. The discovered scaffolds and the elucidated structure-activity relationships provide a basis for the development of future drug candidates for the P2YR which have great potential as novel drugs.
Learn More >The time criteria used in many studies of postherpetic neuralgia (PHN) are arbitrary and do not have supporting evidence. Therefore, this study sought to determine the definite time criterion for PHN by analyzing the skin temperature to estimate the time point when zoster-induced skin inflammatory reaction ends.
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