Global ETD Search

1	Sensitization of dural afferents underlies migraine-related behavior following meningeal application of interleukin-6 (IL-6) Yan, Jin, Melemedjian, Ohannes, Price, Theodore, Dussor, Gregory January 2012 (has links) BACKGROUND:Migraine headache is one of the most common neurological disorders, but the pathophysiology contributing to migraine is poorly understood. Intracranial interleukin-6 (IL-6) levels have been shown to be elevated during migraine attacks, suggesting that this cytokine may facilitate pain signaling from the meninges and contribute to the development of headache.METHODS:Cutaneous allodynia was measured in rats following stimulation of the dura with IL-6 alone or in combination with the MEK inhibitor, U0126. The number of action potentials and latency to the first action potential peak in response to a ramp current stimulus as well as current threshold were measured in retrogradely-labeled dural afferents using patch-clamp electrophysiology. These recordings were performed in the presence of IL-6 alone or in combination with U0126. Association between ERK1 and Nav1.7 following IL-6 treatment was also measured by co-immunoprecipitation.RESULTS:Here we report that in awake animals, direct application of IL-6 to the dura produced dose-dependent facial and hindpaw allodynia. The MEK inhibitor U0126 blocked IL-6-induced allodynia indicating that IL-6 produced this behavioral effect through the MAP kinase pathway. In trigeminal neurons retrogradely labeled from the dura, IL-6 application decreased the current threshold for action potential firing. In response to a ramp current stimulus, cells treated with IL-6 showed an increase in the numbers of action potentials and a decrease in latency to the first spike, an effect consistent with phosphorylation of the sodium channel Nav1.7. Pretreatment with U0126 reversed hyperexcitability following IL-6 treatment. Moreover, co-immunoprecipitation experiments demonstrated an increased association between ERK1 and Nav1.7 following IL-6 treatment.CONCLUSIONS:Our results indicate that IL-6 enhances the excitability of dural afferents likely via ERK-mediated modulation of Nav1.7 and these responses contribute to migraine-related pain behavior in vivo. These data provide a cellular mechanism by which IL-6 in the meninges causes sensitization of dural afferents therefore contributing to the pathogenesis of migraine headache. Migraine Nav1.7 Interleukin-6 Dural afferents Meninges Pain Headache
2	Efectos del disruptor endocrino Bisfenol A en neuronas nociceptoras de ratón: de la bases iónicas a los mecanismos moleculares Gil-Rivera, Minerva 24 September 2021 (has links) Los seres humanos están continuamente expuestos a disruptores endocrinos como el bisfenol A (BPA). El BPA es un componente de los plásticos de policarbonato y resinas epoxi. Se encuentra en muchos productos de uso cotidiano, como envases de comida o el papel térmico de los tickets de la compra. El BPA tiene actividad estrogénica y puede afectar a diversos sistemas del organismo. Se sabe que el 17-β-estradiol aumenta la nocicepción a través de la modulación de diferentes canales iónicos y receptores. Sin embargo, no se conoce el papel del BPA en los mecanismos de nocicepción. En este trabajo, se realizó un estudio para examinar los efectos de una dosis ambientalmente relevante de BPA (1 nM) en la función y expresión de los canales de sodio dependientes de voltaje (Nav) de las neuronas del ganglio de la raíz dorsal (DRG) y determinar el mecanismo de acción del BPA a través de los receptores de estrógenos (ER). Para ello, se llevaron a cabo experimentos electrofisiológicos para analizar los parámetros biofísicos de los canales NaV. Las neuronas tratadas con BPA mostraron un aumento de la corriente de rampa de los canales Nav1.7y de la frecuencia de disparo de potenciales de acción. También se realizó un ensayo de expresión en el que se vio que el BPA no modificaba la expresión de los canales de Nav de las neuronas de los DRGs. Por otra parte, se realizó un experimento de comportamiento para evaluar las respuestas al dolor térmico. Los ratones tratados con inyecciones subdérmicas de BPA (50 μg/kg/día) mostraban un tiempo de respuesta al estímulo menor que los ratones control. Para determinar el mecanismo a través del cual el BPA modificaba las propiedades biofísicas del canal Nav1.7, se utilizaron agonistas y antagonistas de los receptores de estrógenos ERα y ERβ, así como ratones knockout para ERβ. Las neuronas fueron incubadas durante 24 h con 1 mM PPT (agonista de ERα), que ejercía el mismo efecto que el BPA sobre la corriente de rampa. Por otra parte, la acción del BPA fue bloqueada con 100 nM MPP (antagonista de ERα). Además, se observó que la potenciación de la corriente de rampa producida por el BPA se veía disminuida al usar 100 nM wortmanina (inhibidor de PI3K). En conclusión, este estudio sugiere que el BPA altera la corriente de rampa del canal NaV1.7 y aumenta la excitabilidad en neuronas de los DRGs a través de la vía de ERα y PI3K. Nocicepción Ganglio de la raíz dorsal Bisfenol A Canal Nav1.7 Receptor de estrógenos Fisiología
3	UNDERSTANDING THE PATHOPHYSIOLOGY OF MIGRAINE: ACTIVATION AND SENSITIZATION OF DURAL AFFERENTS Yan, Jin January 2011 (has links) Migraine is one of the most common neurological disorders. The pathological conditions that initiate and sensitize afferent pain signaling are poorly understood. The goal of this study is to identify the ion channels and signaling proteins underlying activation and sensitization of meningeal nociceptors.In trigeminal neurons retrogradely labeled from the cranial meninges, approximately 80% responded to a pH 6.0 application with a rapidly activating and desensitizing ASIC-like current. Pharmacological experiments and kinetics analysis demonstrated that dural afferent pH-sensitive currents were mediated via activation of ASIC3. In addition, applications of decreased pH solutions were able to excite these neurons and generate action potentials. In awake animals, application of decreased pH solutions to the dura produced dose-dependent facial and hindpaw allodynia, which was also mediated through activation of ASIC3. Accumulating evidence indicates that meningeal inflammation induced sensitization of dural afferents contributes to migraine headache. We have demonstrated here that in the presence of mast cell mediators, dural afferents showed a decreased pH threshold and increased activity in response to pH stimuli both in vivo and in vitro. These data provide a cellular mechanism by which decreased pH in the meninges directly excites afferent pain-sensing neurons potentially contributing to migraine headache. It also indicates that inflammatory events within the meninges could sensitize afferent pain signaling and result in increased sensitivity of dural afferents.Intracranial Interleukin-6 (IL-6) levels have been shown to be elevated during migraine attacks, suggesting that this cytokine may facilitate pain signaling from the meninges. Here we reported that in awake animals, direct application of IL-6 to the dura produced dose-dependent facial and hindpaw allodynia via activation of the ERK signaling pathway. IL-6 application was also able to increase neuronal excitability in a manner consistent with phosphorylation of Nav1.7. These data provide a cellular mechanism by which IL-6 in the meninges causes sensitization of dural afferents therefore contributing to the pathogenesis of migraine.These findings are discussed in relation to how activation and sensitization of primary afferent neurons might initiate migraine pain signaling and how the research included in this dissertation relates to the development of new therapeutic strategies for migraine. Interleukin 6 Migraine Nav1.7 Medical Pharmacology acid sensing ion channels dural afferents
4	Gating of the sensory neuronal voltage-gated sodium channel Nav1.7 analysis of the role of D3 and D4 / S4-S5 linkers in transition to an inactivated state / Jarecki, Brian W. January 2010 (has links) Thesis (Ph.D.)--Indiana University, 2010. / Title from screen (viewed on April 1, 2010). Department of Pharmacology and Toxicology, Indiana University-Purdue University Indianapolis (IUPUI). Advisor(s): Theodore R. Cummins, Grant D. Nicol, Gerry S. Oxford, Andy Hudmon, John H. Schild. Includes vitae. Includes bibliographical references (leaves 232-266).
5	GATING OF THE SENSORY NEURONAL VOLTAGE-GATED SODIUM CHANNEL NAv1.7: ANALYSIS OF THE ROLE OF D3 AND D4 / S4-S5 LINKERS IN TRANSITION TO AN INACTIVATED STATE Jarecki, Brian W. 01 April 2010 (has links) Indiana University-Purdue University Indianapolis (IUPUI) / Voltage-gated sodium channels (VGSCs) are dynamic membrane-spanning proteins crucial for determining the electrical excitability in nerve and muscle. VGSCs transition, or gate, between opened, closed, and inactivated states, in response to changes in transmembrane potential. Altered VGSC gating can affect electrical communication and is implicated in numerous channelopathies. Nav1.7, a VGSC isoform highly expressed in the peripheral nervous system, plays a unique role in pain perception as evidenced by single point missense mutations causing a spectrum of pain syndromes (inherited erythromelalgia; IEM and paroxysmal extreme pain disorder; PEPD) and nonsense mutations resulting in human insensitivity to pain (CIP). These studies indicate Nav1.7 is critical in pain transduction and, as such, structural perturbations to Nav1.7 affecting conformational stability and response to changes in transmembrane potential have the potential to cause pain. Therefore, the aims of this dissertation were to (1) examine the effects of PEPD mutations on the voltage-dependent properties Nav1.7; (2) investigate the effects Nav1.7 alternative splicing has on the impact of IEM and PEPD mutations; (3) evaluate the effects channelopathies, resulting from slowed inactivation, have on modulating an unusual type of sodium current that flows during membrane repolarization; and (4) determine the structural components involved in stabilizing Nav1.7 inactivation. Standard patch-clamp electrophysiology was used to study changes in channel properties. Results from this dissertation demonstrate that (1) PEPD mutations significantly shift the voltage-dependent properties of Nav1.7 channels, destabilize an inactivated state in a residue specific manner, and render nociceptive neurons hyperexcitable; (2) alternative splicing can functionally impact PEPD; (3) channelopathies, resulting from slowed inactivation in neuronal and muscle VGSC isoforms, increase an unusual sodium conductance that flows during repolarization; and (4) specific residues located in distinct regions of Nav1.7 serve as docking sites to stabilize inactivation at different membrane potentials. Overall, this dissertation answers key questions regarding the molecular mechanics required during inactivation and the biophysical consequences of Nav1.7 mutations implicated in painful disorders. The results of this dissertation are important for a more detailed understanding of pain perception and validate the applicability of studying Nav1.7 for discovery of therapeutic targets for treatment of pain. – Theodore R. Cummins, Chair Ion channel Structure IEM PEPD Pain VGSCs Nav1.7 Gating Electrophysiology Sodium channel Voltage-gated Sodium channels Pain perception Electrophysiology
6	Význam modulace nociceptivního synaptického přenosu na míšní úrovni za různých bolestivých stavů / The role of nociceptive synaptic transmission modulation at the spinal cord level in different pain states Adámek, Pavel January 2019 (has links) Pain is a common symptom of many clinical syndromes and diseases. In particular, the treatment of neuropathic pain represents a serious public health issue because currently available analgesia is ineffective in many cases or it has adverse effects. Treatment of pain-related suffering requires knowledge of how pain signals are initially generated and subsequently transmitted by the nervous system. A nociceptive system plays a key role in this process of encoding and transmission of pain signals. Modulation of the nociceptive synaptic transmission in the spinal cord dorsal horn represents an important mechanism in the development and maintenance of different pathological pain states. This doctoral thesis has aimed to investigate and clarify some of the mechanisms involved in the modulation of the spinal nociceptive processing in different pain states. The main attention was paid to study the following issues: (I.) Which is the role of Transient Receptor Potential Vanilloid type 1 channels (TRPV1), Toll-Like Receptors 4 (TLR4), and phosphatidylinositol 3-kinase (PI3K) in the development of neuropathic pain induced by paclitaxel (PAC) chemotherapy in acute in vitro, and subchronic in vivo murine model of PAC-induced peripheral neuropathy (PIPN)? (II.) How is affected spinal inhibitory synaptic control...
7	Interplay between collapsin response mediator protein 2 (CRMP2) phosphorylation and sumoylation modulates NaV1.7 trafficking Dustrude, Erik Thomas 06 July 2015 (has links) Indiana University-Purdue University Indianapolis (IUPUI) / The voltage-gated sodium channel Nav1.7 has gained traction as a pain target with recognition that loss-of-function mutations in SCN9A, the gene encoding Nav1.7, are associated with congenital insensitivity to pain, whereas gain-of-function mutations produce distinct pain syndromes due to increased Nav1.7 activity. Selective inhibition of Nav1.7 is fundamental to modulating pain via this channel. Understanding the regulation of Nav1.7 at the cellular and molecular level is critical for advancing better therapeutics for pain. Although trafficking of Nav1.7 remains poorly understood, recent studies have begun to investigate post-translational modifications of Navs and/or auxiliary subunits as well as protein-protein interactions as Nav-trafficking mechanisms. Here, I tested if post-translational modifications of a novel Nav1.7-interacting protein, the axonal collapsin response mediator protein 2 (CRMP2) by small ubiquitin-like modifier (SUMO) and phosphorylation could affect Nav trafficking and function. Expression of a CRMP2 SUMOylation incompetent mutant (CRMP2-K374A) in neuronal model CAD cells, which express predominantly Nav1.7 currents, led to a significant reduction in huwentoxin-IV-sensitive Nav1.7 currents. Increasing deSUMOylation with sentrin/SUMO-specific protease SENP1 or SENP2 in wildtype CRMP2-expressing CAD cells decreased Nav1.7 currents. Consistent with reduced current density, biotinylation revealed significant reduction in surface Nav1.7 levels of CAD cells expressing CRMP2-K374A or SENP proteins. Diminution of Nav1.7 sodium current was recapitulated in sensory neurons expressing CRMP2-K374A. Because CRMP2 functions are regulated by its phosphorylation state, I next investigated possible interplay between phosphorylation and SUMOylation of CRMP2 on Nav1.7. Phosphorylation of CRMP2 by cyclin dependent kinase 5 (Cdk5) was necessary for maintaining Nav1.7 surface expression and current density whereas phosphorylation by Fyn kinase reduced CRMP2 SUMOylation and Nav1.7 current density. Binding to Nav1.7 was decreased following (i) loss of CRMP2 SUMOylation, (ii) loss of CRMP2 phosphorylation by Cdk5, or (iii) gain of CRMP2 phosphorylation by Fyn. Altering CRMP2 modification events simultaneously was not synergistic in reducing Nav1.7 currents, suggesting that Nav1.7 co-opts multiple CRMP2 modifications for regulatory control of this channel. Loss of either CRMP2 SUMOylation or Cdk5 phosphorylation triggered Nav1.7 internalization involving E3 ubiquitin ligase Nedd4-2 as well as endocytosis adaptor proteins Numb and Eps15. Collectively, my findings identify a novel mechanism for regulation of Nav1.7. collapsin response mediator protein CRMP2 Nav1.7 phosphorylation SUMOylation voltage gated sodium channel Pain perception Sodium channels Electrophysiology Calcium channels -- Research Neurotransmitters Phosphoproteins
8	Development of Pharmacologically Distinct Opioid Analgesics Patel, Shivani 29 September 2022 (has links) Opioid analgesics have been a major contribution to pain therapy with opioids being used as an effective treatment for various recalcitrant pain conditions. The drug class has come under increased scrutiny due to the raising concerns about the public health crisis of opioid misuse and addiction, thereby increasing the need for alternative and safer analgesics. The exploration of alternative pharmacotherapy for pain management has led to an increasing paradigm shift towards the development of a single-drug-multiple-target approach that takes inspiration from numerous naturally occurring drugs. The mu-opioid receptor has been the primary target for the management of pain; however, the voltage-gated sodium channel Nav1.7 is gaining attention as a putative antinociceptive target based on human genetic evidence. The proposed research aims to develop multi-target directed ligands (MTDL) that modulates two key targets for pain perception, the MOR, and Nav1.7 to generate analgesics with reduced side effects and enhanced analgesia. This will be achieved by exploiting polypharmacology to develop hybrid analgesia in two ways: (i) performing structure-activity relationship (SAR) studies to design a single drug with two pharmacophores that specifically interacts with both the targets (ii) exploiting in silico techniques by performing structure-based virtual ligand screening (VLS) of a chemical library. In our work, we report that through SAR studies and molecular docking studies that the designed compounds having in combination the pharmacophore of PZM21 and aryl sulfonamide demonstrate significant interactions between the active compounds and both the MOR and Nav1.7 proteins. This study also reports the first ever bifunctional virtual ligand screening where a library consisting of over a million compounds was screened for bifunctional activity at the MOR and the Nav1.7 ion channel. We also report the development of a novel mechanism-specific membrane potential assay to that can be used to screen for subtype selective Nav1.7 inhibitors. The research performed in this thesis will serve as a platform to explore the possibility of MTDL as potential therapeutic solutions to diseases of complex etiologies such as chronic pain. It will also serve as a starting point to exploring bifunctional VLS as a way to screen large chemical libraries for MTDLs. Opioids Mu Opioid Receptor Nav1.7 Voltage Gated Sodium Ion Channel Multi target directed ligands Bifunctional compounds PZM21 Aryl Sulfonamide Structure Activity Relationship Studies Bifunctional Virtual Ligand Screening
9	Transforming the Brute : On the Ethical Acceptability of Creating Painless Animals Mittelstadt, Brent January 2009 (has links) <p><p><em>Transforming the Brute</em> addresses the ethical acceptability of creating painless animals for usage in biomedical experimentation. In recent decades the possibility of creating genetically decerebrate animals or AMLs for human ends has been discussed in scientific, academic, and corporate communities. While the ability to create animals that cannot feel, experience, and are more plant than animal remains science fiction, biomedicine may now be able to eliminate or significantly reduce the capacity to feel pain and nociception through genetic engineering. With this new technology comes the opportunity to vastly increase the welfare of animals used in biomedical experimentation, yet this possibility has largely been ignored by the scientific and academic community. This work seeks to reveal the moral necessity of creating painless animals for usage in biomedical experimentation for animal welfare ends. Intrinsic objections relating to animal integrity, rights, companionship, the alteration of telos, humility and virtue are considered. The benefit of eliminating nociceptive pain in experimental animals is addressed, and differences are examined between biomedical experimentation and other usage of animals for human ends which makes the proposed creation of painless animals ethically unique. Finally, an argument is presented for the moral necessity of replacing normal animals with painless animals in biomedical experimentation with consideration given to genetically decerebrate animals.</p></p> transforming brute nociception pain genetic engineering manipulation modification modify gene genes bernard rollin animal microencephalic lumps decerebrate aml amls painless painlessness integrity dignity rights companionship telos alteration biomedicine biomedical experiment experimentation agriculture farm suffering distress capacity bioethics ethics applied mice scn9a nav1.7 gene therapy germ line Ethics Etik
10	Transforming the Brute : On the Ethical Acceptability of Creating Painless Animals Mittelstadt, Brent January 2009 (has links) Transforming the Brute addresses the ethical acceptability of creating painless animals for usage in biomedical experimentation. In recent decades the possibility of creating genetically decerebrate animals or AMLs for human ends has been discussed in scientific, academic, and corporate communities. While the ability to create animals that cannot feel, experience, and are more plant than animal remains science fiction, biomedicine may now be able to eliminate or significantly reduce the capacity to feel pain and nociception through genetic engineering. With this new technology comes the opportunity to vastly increase the welfare of animals used in biomedical experimentation, yet this possibility has largely been ignored by the scientific and academic community. This work seeks to reveal the moral necessity of creating painless animals for usage in biomedical experimentation for animal welfare ends. Intrinsic objections relating to animal integrity, rights, companionship, the alteration of telos, humility and virtue are considered. The benefit of eliminating nociceptive pain in experimental animals is addressed, and differences are examined between biomedical experimentation and other usage of animals for human ends which makes the proposed creation of painless animals ethically unique. Finally, an argument is presented for the moral necessity of replacing normal animals with painless animals in biomedical experimentation with consideration given to genetically decerebrate animals. transforming brute nociception pain genetic engineering manipulation modification modify gene genes bernard rollin animal microencephalic lumps decerebrate aml amls painless painlessness integrity dignity rights companionship telos alteration biomedicine biomedical experiment experimentation agriculture farm suffering distress capacity bioethics ethics applied mice scn9a nav1.7 gene therapy germ line Ethics Etik

Search results