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Waheed S, Ramzan K, Ahmad S, Khan MS, Wajid M, Ullah H, Umar A, Iqbal R, Ullah R, Bari A. Identification and In-Silico study of non-synonymous functional SNPs in the human SCN9A gene. PLoS One 2024; 19:e0297367. [PMID: 38394191 PMCID: PMC10889873 DOI: 10.1371/journal.pone.0297367] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2023] [Accepted: 12/29/2023] [Indexed: 02/25/2024] Open
Abstract
Single nucleotide polymorphisms are the most common form of DNA alterations at the level of a single nucleotide in the genomic sequence. Genome-wide association studies (GWAS) were carried to identify potential risk genes or genomic regions by screening for SNPs associated with disease. Recent studies have shown that SCN9A comprises the NaV1.7 subunit, Na+ channels have a gene encoding of 1988 amino acids arranged into 4 domains, all with 6 transmembrane regions, and are mainly found in dorsal root ganglion (DRG) neurons and sympathetic ganglion neurons. Multiple forms of acute hypersensitivity conditions, such as primary erythermalgia, congenital analgesia, and paroxysmal pain syndrome have been linked to polymorphisms in the SCN9A gene. Under this study, we utilized a variety of computational tools to explore out nsSNPs that are potentially damaging to heath by modifying the structure or activity of the SCN9A protein. Over 14 potentially damaging and disease-causing nsSNPs (E1889D, L1802P, F1782V, D1778N, C1370Y, V1311M, Y1248H, F1237L, M936V, I929T, V877E, D743Y, C710W, D623H) were identified by a variety of algorithms, including SNPnexus, SNAP-2, PANTHER, PhD-SNP, SNP & GO, I-Mutant, and ConSurf. Homology modeling, structure validation, and protein-ligand interactions also were performed to confirm 5 notable substitutions (L1802P, F1782V, D1778N, V1311M, and M936V). Such nsSNPs may become the center of further studies into a variety of disorders brought by SCN9A dysfunction. Using in-silico strategies for assessing SCN9A genetic variations will aid in organizing large-scale investigations and developing targeted therapeutics for disorders linked to these variations.
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Affiliation(s)
- Sana Waheed
- Faculty of Life Science, Department of Zoology, University of Okara, Okara, Pakistan
| | - Kainat Ramzan
- Faculty of Life Science, Department of Biochemistry, University of Okara, Okara, Pakistan
| | - Sibtain Ahmad
- Faculty of Animal Husbandry, Institute of Animal and Dairy Sciences, University of Agriculture, Faisalabad, Pakistan
| | - Muhammad Saleem Khan
- Faculty of Life Science, Department of Zoology, University of Okara, Okara, Pakistan
| | - Muhammad Wajid
- Faculty of Life Science, Department of Zoology, University of Okara, Okara, Pakistan
| | - Hayat Ullah
- Department of Chemistry, University of Okara, Okara, Pakistan
| | - Ali Umar
- Faculty of Life Science, Department of Zoology, University of Okara, Okara, Pakistan
| | - Rashid Iqbal
- Faculty of Agriculture and Environment, Department of Agronomy, The Islamia University of Bahawalpur, Bahawalpur, Pakistan
| | - Riaz Ullah
- Department of Pharmacognosy College of Pharmacy King Saud University, Riyadh, Saudi Arabia
| | - Ahmed Bari
- Department of Pharmaceutical Chemistry, College of Pharmacy King Saud University, Riyadh, Saudi Arabia
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Wu X, Zhang H, Long H, Zhang D, Yang X, Liu D, E G. Genome-Wide Selection Signal Analysis to Investigate Wide Genomic Heredity Divergence between Eurasian Wild Boar and Domestic Pig. Animals (Basel) 2023; 13:2158. [PMID: 37443955 DOI: 10.3390/ani13132158] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2023] [Revised: 06/26/2023] [Accepted: 06/28/2023] [Indexed: 07/15/2023] Open
Abstract
As important livestock species, pigs provide essential meat resources for humans, so understanding the genetic evolution behind their domestic history could help with the genetic improvement of domestic pigs. This study aimed to investigate the evolution of convergence and divergence under selection in European and Asian domestic pigs by using public genome-wide data. A total of 164 and 108 candidate genes (CDGs) were obtained from the Asian group (wild boar vs. domestic pig) and the European group (wild boar vs. domestic pig), respectively, by taking the top 5% of intersected windows of a pairwise fixation index (FST) and a cross population extended haplotype homozygosity test (XPEHH). GO and KEGG annotated results indicated that most CDGs were related to reproduction and immunity in the Asian group. Conversely, rich CDGs were enriched in muscle development and digestion in the European group. Eight CDGs were subjected to parallel selection of Eurasian domestic pigs from local wild boars during domestication. These CDGs were mainly involved in olfactory transduction, metabolic pathways, and progesterone-mediated oocyte maturation. Moreover, 36 and 18 haplotypes of INPP5B and TRAK2 were identified in this study, respectively. In brief, this study did not only improve the understanding of the genetic evolution of domestication in pigs, but also provides valuable CDGs for future breeding and genetic improvement of pigs.
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Affiliation(s)
- Xinming Wu
- College of Animal Science and Technology, Southwest University, Chongqing 400716, China
| | - Haoyuan Zhang
- College of Animal Science and Technology, Southwest University, Chongqing 400716, China
| | - Haoyuan Long
- College of Animal Science and Technology, Southwest University, Chongqing 400716, China
| | - Dongjie Zhang
- Institute of Animal Husbandry, Heilongjiang Academy of Agricultural Sciences, Harbin 150086, China
| | - Xiuqin Yang
- College of Animal Science and Technology, Northeast Agricultural University, Harbin 150030, China
| | - Di Liu
- Institute of Animal Husbandry, Heilongjiang Academy of Agricultural Sciences, Harbin 150086, China
| | - Guangxin E
- College of Animal Science and Technology, Southwest University, Chongqing 400716, China
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Ambroxol for neuropathic pain: hiding in plain sight? Pain 2023; 164:3-13. [PMID: 35580314 DOI: 10.1097/j.pain.0000000000002693] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2022] [Accepted: 05/12/2022] [Indexed: 01/09/2023]
Abstract
ABSTRACT Ambroxol is a multifaceted drug with primarily mucoactive and secretolytic actions, along with anti-inflammatory, antioxidant, and local anaesthetic properties. It has a long history of use in the treatment of respiratory tract diseases and has shown to be efficacious in relieving sore throat. In more recent years, ambroxol has gained interest for its potential usefulness in treating neuropathic pain. Research into this area has been slow, despite clear preclinical evidence to support its primary analgesic mechanism of action-blockade of voltage-gated sodium (Na v ) channels in sensory neurons. Ambroxol is a commercially available inhibitor of Na v 1.8, a crucial player in the pathophysiology of neuropathic pain, and Na v 1.7, a particularly exciting target for the treatment of chronic pain. In this review, we discuss the analgesic mechanisms of action of ambroxol, as well as proposed synergistic properties, followed by the preclinical and clinical results of its use in the treatment of persistent pain and neuropathic pain symptoms, including trigeminal neuralgia, fibromyalgia, and complex regional pain syndrome. With its well-established safety profile, extensive preclinical and clinical drug data, and early evidence of clinical effectiveness, ambroxol is an old drug worthy of further investigation for repurposing. As a patent-expired drug, a push is needed to progress the drug to clinical trials for neuropathic pain. We encourage the pharmaceutical industry to look at patented drug formulations and take an active role in bringing an optimized version for neuropathic pain to market.
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Le Cann K, Meents JE, Sudha Bhagavath Eswaran V, Dohrn MF, Bott R, Maier A, Bialer M, Hautvast P, Erickson A, Rolke R, Rothermel M, Körner J, Kurth I, Lampert A. Assessing the impact of pain-linked Nav1.7 variants: An example of two variants with no biophysical effect. Channels (Austin) 2021; 15:208-228. [PMID: 33487118 PMCID: PMC7833769 DOI: 10.1080/19336950.2020.1870087] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2020] [Revised: 12/23/2020] [Accepted: 12/23/2020] [Indexed: 11/30/2022] Open
Abstract
Mutations in the voltage-gated sodium channel Nav1.7 are linked to human pain. The Nav1.7/N1245S variant was described before in several patients suffering from primary erythromelalgia and/or olfactory hypersensitivity. We have identified this variant in a pain patient and a patient suffering from severe and life-threatening orthostatic hypotension. In addition, we report a female patient suffering from muscle pain and carrying the Nav1.7/E1139K variant. We tested both Nav1.7 variants by whole-cell voltage-clamp recordings in HEK293 cells, revealing a slightly enhanced current density for the N1245S variant when co-expressed with the β1 subunit. This effect was counteracted by an enhanced slow inactivation. Both variants showed similar voltage dependence of activation and steady-state fast inactivation, as well as kinetics of fast inactivation, deactivation, and use-dependency compared to WT Nav1.7. Finally, homology modeling revealed that the N1245S substitution results in different intramolecular interaction partners. Taken together, these experiments do not point to a clear pathogenic effect of either the N1245S or E1139K variant and suggest they may not be solely responsible for the patients' pain symptoms. As discussed previously for other variants, investigations in heterologous expression systems may not sufficiently mimic the pathophysiological situation in pain patients, and single nucleotide variants in other genes or modulatory proteins are necessary for these specific variants to show their effect. Our findings stress that biophysical investigations of ion channel mutations need to be evaluated with care and should preferably be supplemented with studies investigating the mutations in their context, ideally in human sensory neurons.
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Affiliation(s)
- Kim Le Cann
- Institute of Physiology, RWTH Aachen University Hospital, Aachen, Germany
| | - Jannis E. Meents
- Institute of Physiology, RWTH Aachen University Hospital, Aachen, Germany
| | | | - Maike F. Dohrn
- Department of Neurology, Medical Faculty, RWTH Aachen University Hospital, Aachen, Germany
| | - Raya Bott
- Institute of Physiology, RWTH Aachen University Hospital, Aachen, Germany
| | - Andrea Maier
- Department of Neurology, Medical Faculty, RWTH Aachen University Hospital, Aachen, Germany
| | - Martin Bialer
- Division of Clinical Metabolism of Medical Genetics and Human Genomics at Northwell Health System, New-York, United States
| | - Petra Hautvast
- Institute of Physiology, RWTH Aachen University Hospital, Aachen, Germany
| | - Andelain Erickson
- Institute of Physiology, RWTH Aachen University Hospital, Aachen, Germany
| | - Roman Rolke
- Department for Palliative Care, Medical Faculty, RWTH Aachen University, Aachen, Germany
| | - Markus Rothermel
- Department of Chemosensation, AG Neuromodulation, Institute for Biology II, RWTH Aachen University, Aachen, 52074, Germany
| | - Jannis Körner
- Institute of Physiology, RWTH Aachen University Hospital, Aachen, Germany
- Department of Anaesthesiology, Medical Faculty, RWTH Aachen University, Aachen, Germany
| | - Ingo Kurth
- Institute of Human Genetics, Medical Faculty, RWTH Aachen University Hospital, Aachen, Germany
| | - Angelika Lampert
- Institute of Physiology, RWTH Aachen University Hospital, Aachen, Germany
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Palmieri B, Corazzari V, Vadalaʹ M, Vallelunga A, Morales-Medina JC, Iannitti T. The role of sensory and olfactory pathways in multiple chemical sensitivity. REVIEWS ON ENVIRONMENTAL HEALTH 2021; 36:319-326. [PMID: 33070122 DOI: 10.1515/reveh-2020-0058] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/20/2020] [Accepted: 09/15/2020] [Indexed: 06/11/2023]
Abstract
Multiple chemical sensitivity (MCS) is characterised by non-specific and recurring symptoms affecting multiple organs and associated with exposure to chemicals, even at low concentrations, which are, under normal circumstances, harmless to the general population. Symptoms include general discomfort, cardiovascular instability, irritation of the sensory organs, breath disorders, hypersensitivity affecting the skin and epithelial lining of the gut, throat and lungs, anxiety, and learning and memory loss. Chemical intolerance is a key distinguishing feature of MCS, limiting considerably patients' lifestyle with serious social, occupational and economic implications. Since no specific diagnostic markers are currently available for chemical intolerance, the diagnosis relies on clinical symptoms. Despite the formulation of several hypotheses regarding the pathophysiology of MCS, its mechanisms remain undefined. A person-centred care approach, based on multidisciplinary and individualised medical plans, has shown promising results. However, more definite treatment strategies are required. We have reviewed the main experimental studies on MCS pathophysiology, focusing on the brain networks involved, the impact of environmental pollution on the olfactory system and the correlation with other pathologies such as neurodegenerative diseases. Finally, we discuss treatment strategies targeting the olfactory system.
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Affiliation(s)
- Beniamino Palmieri
- Surgical, Medical, Dental and Morphological Sciences Departments with interest in Transplants, Oncology and Regenerative Medicine, University of Modena and Reggio Emilia, Modena, Italy
- Network of Second Opinion, Modena, Italy
| | | | - Maria Vadalaʹ
- Surgical, Medical, Dental and Morphological Sciences Departments with interest in Transplants, Oncology and Regenerative Medicine, University of Modena and Reggio Emilia, Modena, Italy
- Network of Second Opinion, Modena, Italy
| | - Annamaria Vallelunga
- Department of Medicine and Surgery, Centre for Neurodegenerative Diseases (CEMAND), University of Salerno, Salerno, Italy
| | - Julio César Morales-Medina
- Centro de Investigación en Reproducción Animal, CINVESTAV- Universidad Autónoma de Tlaxcala, Tlaxcala, Mexico
| | - Tommaso Iannitti
- Charles River Discovery Research Services UK Limited, Portishead, UK
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Sandri A, Cecchini MP, Riello M, Zanini A, Nocini R, Fiorio M, Tinazzi M. Pain, Smell, and Taste in Adults: A Narrative Review of Multisensory Perception and Interaction. Pain Ther 2021; 10:245-268. [PMID: 33635507 PMCID: PMC8119564 DOI: 10.1007/s40122-021-00247-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2021] [Accepted: 02/13/2021] [Indexed: 12/31/2022] Open
Abstract
Every day our sensory systems perceive and integrate a variety of stimuli containing information vital for our survival. Pain acts as a protective warning system, eliciting a response to remove harmful stimuli; it may also be a symptom of an illness or present as a disease itself. There is a growing need for additional pain-relieving therapies involving the multisensory integration of smell and taste in pain modulation, an approach that may provide new strategies for the treatment and management of pain. While pain, smell, and taste share common features and are strongly linked to emotion and cognition, their interaction has been poorly explored. In this review, we provide an overview of the literature on pain modulation by olfactory and gustatory substances. It includes adult human studies investigating measures of pain threshold, tolerance, intensity, and/or unpleasantness. Due to the limited number of studies currently available, we have structured this review as a narrative in which we comment on experimentally induced and clinical pain separately on pain–smell and pain–taste interaction. Inconsistent study findings notwithstanding, pain, smell, and taste seem to interact at both the behavioral and the neural levels. Pain intensity and unpleasantness seem to be affected more by olfactory substances, whereas pain threshold and tolerance are influenced by gustatory substances. Few pilot studies to date have investigated these effects in clinical populations. While the current results are promising for the future, more evidence is needed to elucidate the link between the chemical senses and pain. Doing so has the potential to improve and develop novel options for pain treatment.
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Affiliation(s)
- Angela Sandri
- Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona, Verona, Italy.
| | - Maria Paola Cecchini
- Anatomy and Histology Section, Department of Neuroscience, Biomedicine and Movement Sciences, University of Verona, Verona, Italy
| | - Marianna Riello
- Neurology Unit, Department of Neuroscience, Biomedicine and Movement Sciences, University of Verona, Verona, Italy
| | - Alice Zanini
- Anatomy and Histology Section, Department of Neuroscience, Biomedicine and Movement Sciences, University of Verona, Verona, Italy
| | - Riccardo Nocini
- Otolaryngology Section, Department of Surgery, Dentistry, Paediatrics and Gynaecology , University of Verona, Verona, Italy
| | - Mirta Fiorio
- Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona, Verona, Italy
| | - Michele Tinazzi
- Neurology Unit, Department of Neuroscience, Biomedicine and Movement Sciences, University of Verona, Verona, Italy.
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Cecchini MP, Riello M, Sandri A, Zanini A, Fiorio M, Tinazzi M. Smell and taste dissociations in the modulation of tonic pain perception induced by a capsaicin cream application. Eur J Pain 2020; 24:1946-1955. [PMID: 32780473 DOI: 10.1002/ejp.1644] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2020] [Revised: 08/04/2020] [Accepted: 08/05/2020] [Indexed: 12/12/2022]
Abstract
BACKGROUND Pain is a subjective experience characterized by sensory (intensity) and emotional (unpleasantness) aspects. Although literature reports behavioural effects on pain due to smell and taste influence, to our knowledge the relationship between tonic pain induced by a capsaicin cream and these chemosensory systems has never been explored before. The aim of this study was to investigate the modulation of olfactory and gustatory substances having different valence on tonic pain perception mediated by a capsaicin cream application. METHODS Sixty healthy volunteers were included in two separated experiments (N = 30 smell; N = 30 taste) and underwent different valence smell and taste stimulations, while receiving painful stimuli. Perception of pain intensity (the sensory component) and unpleasantness (the affective component) was measured with a numerical rating scale, both during the two aforementioned experiments. RESULTS Pain unpleasantness rating showed differences only in the smell experiment between the two odourous conditions. In particular, pleasant odour induced lower ratings of pain unpleasantness, while no significant results were found for intensity. Regarding taste, we could not observe significant effects nor for pain unpleasantness or intensity. CONCLUSIONS These findings highlight the potential role of pleasant odours in influencing the affective aspects of pain perception induced by this kind of tonic pain. Such evidence might provide new insight for using chemosensory substances as analgesics for modulating the cognitive aspects of neuropathic pain. SIGNIFICANCE This work shows the effect of smell on the emotional component of tonic pain, experimentally induced by capsaicin cream application. Previous literature investigated tonic pain in interaction with smell and/or taste stimuli, but mainly with physical methods such as temperature. Our findings add new information in this field, contributing to a deeper insight on the role of olfaction on this particular kind of tonic pain perception. This approach could open to new investigations aimed to consider odours for pain management.
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Affiliation(s)
- Maria Paola Cecchini
- Anatomy and Histology Section, Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona, Verona, Italy
| | - Marianna Riello
- Neurology Unit, Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona, Verona, Italy
| | - Angela Sandri
- Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona, Verona, Italy
| | - Alice Zanini
- Anatomy and Histology Section, Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona, Verona, Italy
| | - Mirta Fiorio
- Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona, Verona, Italy
| | - Michele Tinazzi
- Neurology Unit, Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona, Verona, Italy
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Painful and painless mutations of SCN9A and SCN11A voltage-gated sodium channels. Pflugers Arch 2020; 472:865-880. [PMID: 32601768 PMCID: PMC7351857 DOI: 10.1007/s00424-020-02419-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2020] [Revised: 05/25/2020] [Accepted: 06/10/2020] [Indexed: 12/11/2022]
Abstract
Chronic pain is a global problem affecting up to 20% of the world’s population and has a significant economic, social and personal cost to society. Sensory neurons of the dorsal root ganglia (DRG) detect noxious stimuli and transmit this sensory information to regions of the central nervous system (CNS) where activity is perceived as pain. DRG neurons express multiple voltage-gated sodium channels that underlie their excitability. Research over the last 20 years has provided valuable insights into the critical roles that two channels, NaV1.7 and NaV1.9, play in pain signalling in man. Gain of function mutations in NaV1.7 cause painful conditions while loss of function mutations cause complete insensitivity to pain. Only gain of function mutations have been reported for NaV1.9. However, while most NaV1.9 mutations lead to painful conditions, a few are reported to cause insensitivity to pain. The critical roles these channels play in pain along with their low expression in the CNS and heart muscle suggest they are valid targets for novel analgesic drugs.
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Tajerian M, Alvarado SG, Clark JD. Differential olfactory bulb methylation and hydroxymethylation are linked to odor location memory bias in injured mice. Mol Pain 2020; 15:1744806919873475. [PMID: 31407613 PMCID: PMC6712758 DOI: 10.1177/1744806919873475] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Chronic pain is often linked to comorbidities such as anxiety and cognitive dysfunction, alterations that are reflected in brain plasticity in regions such as the prefrontal cortex and the limbic area. Despite the growing interest in pain-related cognitive deficits, little is known about the relationship between the emotional valence of the stimulus and the salience of its memory following painful injuries. We used the tibia fracture model of chronic pain in mice to determine whether pleasant and unpleasant odor location memories differ in their salience seven weeks following the onset of the painful injury. Our results indicate that injured mice show a bias toward recalling unpleasant memories, thereby propagating the vicious cycle of chronic pain and negative affect. Next, we linked these behavioral differences to mechanisms of molecular plasticity by measuring the levels of global methylation and hydroxymethylation in the olfactory bulb. Compared to controls, global methylation levels were shown to be increased, while hydroxymethylation levels were decreased in the olfactory bulb of injured mice, indicative of overall changes in DNA regulation machinery and the subsequent alterations in sensory systems.
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Affiliation(s)
- Maral Tajerian
- 1 Department of Biology, Queens College, City University of New York, Queens, NY, USA
| | - Sebastian G Alvarado
- 1 Department of Biology, Queens College, City University of New York, Queens, NY, USA
| | - J David Clark
- 2 Veterans Affairs Palo Alto Health Care System, Palo Alto, CA, USA.,3 Department of Anesthesiology, Stanford University School of Medicine, Stanford, CA, USA.,4 Palo Alto Veterans Institute for Research, Palo Alto, CA, USA
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Riello M, Cecchini MP, Zanini A, Di Chiappari M, Tinazzi M, Fiorio M. Perception of phasic pain is modulated by smell and taste. Eur J Pain 2019; 23:1790-1800. [PMID: 31291496 DOI: 10.1002/ejp.1453] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2019] [Revised: 07/02/2019] [Accepted: 07/04/2019] [Indexed: 12/12/2022]
Abstract
BACKGROUND Pain perception is a multimodal experience composed of sensory, emotional and cognitive dimensions. Accumulating evidence suggests that the chemical senses can influence pain perception, but their relation with phasic pain is still unknown. The aim of this study was to investigate the influence of smell and taste having different valence on phasic pain. METHODS Twenty-eight healthy volunteers received sweet, bitter and neutral odours or gustatory substances while receiving painful stimuli consisting of electrical shocks. Tactile threshold, pain threshold and pain tolerance were collected using the psychophysical method of limits at baseline and in association with smell and taste. Perception of pain intensity and unpleasantness was measured with a numerical rating scale. RESULTS Sweet smell induced lower ratings of pain intensity than bitter smell when stimuli were delivered at pain threshold. Sweet smell also induced lower ratings of pain unpleasantness than neutral smell when stimuli were delivered at pain tolerance. Sweet taste induced lower ratings of pain unpleasantness than bitter taste when stimuli were delivered at pain threshold. Conversely, pain threshold and pain tolerance per se were not affected by smell and taste. CONCLUSIONS These findings highlight an effect of sweet substances in reducing the subjective perception of pain intensity and unpleasantness associated to phasic pain. SIGNIFICANCE By demonstrating the link between smell, taste and phasic pain this study may have a translational impact in clinical conditions characterized by so-called shock-like pain, such as neuropathic pain.
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Affiliation(s)
- Marianna Riello
- Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona, Verona, Italy
| | - Maria Paola Cecchini
- Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona, Verona, Italy
| | - Alice Zanini
- Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona, Verona, Italy
| | - Miguel Di Chiappari
- Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona, Verona, Italy
| | - Michele Tinazzi
- Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona, Verona, Italy
| | - Mirta Fiorio
- Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona, Verona, Italy
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Kern KU, Schwickert-Nieswandt M, Maihöfner C, Gaul C. Topical Ambroxol 20% for the Treatment of Classical Trigeminal Neuralgia - A New Option? Initial Clinical Case Observations. Headache 2019; 59:418-429. [PMID: 30653673 DOI: 10.1111/head.13475] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/30/2018] [Indexed: 12/17/2022]
Abstract
BACKGROUND Trigeminal neuralgia is difficult to treat and shows upregulation of sodium channels. The expectorant ambroxol acts as a strong local anesthetic, about 40 times stronger than lidocaine. It preferentially inhibits the channel subtype Nav 1.8, expressed especially in nociceptive C-fibers. It seemed reasonable to try ambroxol for the treatment with neuropathic facial pain unresponsive to other standard options. MATERIAL AND METHODS Medical records of patients suffering from classical trigeminal neuralgia (n = 5) and successful pain reduction following topical ambroxol 20% cream in addition to standard treatment are reported. RESULTS All patients reported pain attacks with pain intensity between 4 and 10 NRS (numeric pain scale). In all cases they could be triggered, 3 patients reported additional spontaneous pain. Attacks were reduced in all 5 patients. Pain reduction achieved following ambroxol 20% cream was 2-8 points (NRS) earliest within 15-30 minutes and lasted for 4-6 hours mostly. This was reproducible in all cases; in one case pain was eliminated after 1 week. No patient reported side effects or skin changes; oral medication was reduced in 2 patients. CONCLUSION For the first time, a clinically significant pain relief following topical ambroxol 20% cream in patients with trigeminal neuralgia is reported. In view of the positive side effect profile, topical ambroxol for patients with such a highly impaired quality of life should be investigated further as a matter of urgency.
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Affiliation(s)
- Kai-Uwe Kern
- Institute for Pain Medicine/Pain Practice Wiesbaden, Wiesbaden, Germany
| | | | | | - Charly Gaul
- Migraine and Headache Clinic, Königstein, Germany
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