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Abstract
Clinical and basic research on regulation of pituitary hormones, extra-pituitary release of these hormones, distribution of their receptors and cell signaling pathways recruited upon receptor binding suggests that pituitary hormones can regulate mechanisms of nociceptive transmission in multiple orofacial pain conditions. Moreover, many pituitary hormones either regulate glands that produce gonadal hormones (GnH) or are regulated by GnH. This implies that pituitary hormones may be involved in sex-dependent mechanisms of orofacial pain and could help explain why certain orofacial pain conditions are more prevalent in women than men. Overall, regulation of nociception by pituitary hormones is a relatively new and emerging area of pain research. The aims of this review article are to: (1) present an overview of clinical conditions leading to orofacial pain that are associated with alterations of serum pituitary hormone levels; (2) discuss proposed mechanisms of how pituitary hormones could regulate nociceptive transmission; and (3) outline how pituitary hormones could regulate nociception in a sex-specific fashion. Pituitary hormones are routinely used for hormonal replacement therapy, while both receptor antagonists and agonists are used to manage certain pathological conditions related to hormonal imbalance. Administration of these hormones may also have a place in the treatment of pain, including orofacial pain. Hence, understanding the involvement of pituitary hormones in orofacial pain, especially sex-dependent aspects of such pain, is essential to both optimize current therapies as well as provide novel and sex-specific pharmacology for a diversity of associated conditions.
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Affiliation(s)
- Gregory Dussor
- School of Behavioral and Brain Sciences, University of Texas at Dallas, Richardson, TX, United States
| | - Jacob T Boyd
- Department of Cellular and Integrative Physiology, University of Texas Health Science Center at San Antonio, San Antonio, TX, United States
| | - Armen N Akopian
- Department of Endodontics, University of Texas Health Science Center at San Antonio, San Antonio, TX, United States.,Department of Pharmcology, University of Texas Health Science Center at San Antonio, San Antonio, TX, United States
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Black BJ, Atmaramani R, Kumaraju R, Plagens S, Romero-Ortega M, Dussor G, Price TJ, Campbell ZT, Pancrazio JJ. Adult mouse sensory neurons on microelectrode arrays exhibit increased spontaneous and stimulus-evoked activity in the presence of interleukin-6. J Neurophysiol 2018; 120:1374-1385. [PMID: 29947589 DOI: 10.1152/jn.00158.2018] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Following inflammation or injury, sensory neurons located in the dorsal root ganglia (DRG) may exhibit increased spontaneous and/or stimulus-evoked activity, contributing to chronic pain. Current treatment options for peripherally mediated chronic pain are highly limited, driving the development of cell- or tissue-based phenotypic (function-based) screening assays for peripheral analgesic and mechanistic lead discovery. Extant assays are often limited by throughput, content, use of tumorigenic cell lines, or tissue sources from immature developmental stages (i.e., embryonic or postnatal). Here, we describe a protocol for culturing adult mouse DRG neurons on substrate-integrated multiwell microelectrode arrays (MEAs). This approach enables multiplexed measurements of spontaneous as well as stimulus-evoked extracellular action potentials from large populations of cells. The DRG cultures exhibit stable spontaneous activity from 9 to 21 days in vitro. Activity is readily evoked by known chemical and physical agonists of sensory neuron activity such as capsaicin, bradykinin, PGE2, heat, and electrical field stimulation. Most importantly, we demonstrate that both spontaneous and stimulus-evoked activity may be potentiated by incubation with the inflammatory cytokine interleukin-6 (IL-6). Acute responsiveness to IL-6 is inhibited by treatment with a MAPK-interacting kinase 1/2 inhibitor, cercosporamide. In total, these findings suggest that adult mouse DRG neurons on multiwell MEAs are applicable to ongoing efforts to discover peripheral analgesic and their mechanisms of action. NEW & NOTEWORTHY This work describes methodologies for culturing spontaneously active adult mouse dorsal root ganglia (DRG) sensory neurons on microelectrode arrays. We characterize spontaneous and stimulus-evoked adult DRG activity over durations consistent with pharmacological interventions. Furthermore, persistent hyperexcitability could be induced by incubation with inflammatory cytokine IL-6 and attenuated with cercosporamide, an inhibitor of the IL-6 sensitization pathway. This constitutes a more physiologically relevant, moderate-throughput in vitro model for peripheral analgesic screening as well as mechanistic lead discovery.
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Affiliation(s)
- Bryan J Black
- Department of Bioengineering, The University of Texas at Dallas , Richardson, Texas
| | - Rahul Atmaramani
- Department of Bioengineering, The University of Texas at Dallas , Richardson, Texas
| | - Rajeshwari Kumaraju
- Department of Bioengineering, The University of Texas at Dallas , Richardson, Texas
| | - Sarah Plagens
- Department of Bioengineering, The University of Texas at Dallas , Richardson, Texas
| | - Mario Romero-Ortega
- Department of Bioengineering, The University of Texas at Dallas , Richardson, Texas
| | - Gregory Dussor
- School of Behavioral and Brain Sciences, The University of Texas at Dallas , Richardson, Texas
| | - Theodore J Price
- School of Behavioral and Brain Sciences, The University of Texas at Dallas , Richardson, Texas
| | - Zachary T Campbell
- Department of Biological Sciences, The University of Texas at Dallas, Richardson, Richardson, Texas
| | - Joseph J Pancrazio
- Department of Bioengineering, The University of Texas at Dallas , Richardson, Texas
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Paige C, Maruthy GB, Mejia G, Dussor G, Price T. Spinal Inhibition of P2XR or p38 Signaling Disrupts Hyperalgesic Priming in Male, but not Female, Mice. Neuroscience 2018; 385:133-142. [PMID: 29913243 DOI: 10.1016/j.neuroscience.2018.06.012] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2018] [Revised: 06/01/2018] [Accepted: 06/06/2018] [Indexed: 01/11/2023]
Abstract
Recent studies have demonstrated sexual dimorphisms in the mechanisms contributing to the development of chronic pain. Here we tested the hypothesis that microglia might preferentially regulate hyperalgesic priming in male mice. We based this hypothesis on evidence that microglia preferentially contribute to neuropathic pain in male mice via ionotropic purinergic receptor (P2XR) or p38 mitogen-activated protein kinase (p38) signaling. Mice given a single-priming injection of the soluble human interleukin-6 receptor (IL-6r) and then a second injection of prostaglandin E2 (PGE2), which unmasks hyperalgesic priming, shows a significant increase in levels of activated microglia at 3 h following the PGE2 injection in both male and female mice. There was no change in microglia following PGE2. Intrathecal injection of the P2X3/4 inhibitor TNP-ATP blocked the initial response to IL-6r in both males and females, but only blocked hyperalgesic priming in male mice. Intrathecally applied p38 inhibitor, skepinone, had no effect on the initial response to IL-6r but attenuated hyperalgesic priming in males only. Neither TNP-ATP nor skepinone could reverse priming once it had already been established in male mice suggesting that these pathways must be inhibited early in the development of hyperalgesic priming to have an effect. Our work is consistent with previous findings that P2XR and p38 inhibition can lead to male-specific effects on pain behaviors in mice. However, given that we did not observe microglial activation at time points where these drugs were effective, our work also questions whether these effects can be completely attributed to microglia.
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Affiliation(s)
- Candler Paige
- University of Texas at Dallas, School of Behavioral and Brain Sciences, United States
| | | | - Galo Mejia
- University of Texas at Dallas, School of Behavioral and Brain Sciences, United States
| | - Gregory Dussor
- University of Texas at Dallas, School of Behavioral and Brain Sciences, United States
| | - Theodore Price
- University of Texas at Dallas, School of Behavioral and Brain Sciences, United States.
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54
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Abstract
Acid-sensing ion channels (ASICs) are a family of ion channels, consisting of four members; ASIC1 to 4. These channels are sensitive to changes in pH and are expressed throughout the central and peripheral nervous systems-including brain, spinal cord, and sensory ganglia. They have been implicated in a number of neurological conditions such as stroke and cerebral ischemia, traumatic brain injury, and epilepsy, and more recently in migraine. Their expression within areas of interest in the brain in migraine, such as the hypothalamus and PAG, their demonstrated involvement in preclinical models of meningeal afferent signaling, and their role in cortical spreading depression (the electrophysiological correlate of migraine aura), has enhanced research interest into these channels as potential therapeutic targets in migraine. Migraine is a disorder with a paucity of both acute and preventive therapies available, in which at best 50% of patients respond to available medications, and these medications often have intolerable side effects. There is therefore a great need for therapeutic development for this disabling condition. This review will summarize the understanding of the structure and CNS expression of ASICs, the mechanisms for their potential role in nociception, recent work in migraine, and areas for future research and drug development.
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Affiliation(s)
- Nazia Karsan
- Headache Group, Department of Basic and Clinical Neuroscience, Institute of Psychiatry, Psychology and Neuroscience, Kings College London, Denmark Hill, London, SE5 9PJ, UK
| | - Eric B Gonzales
- TCU and UNTHSC School of Medicine (applicant for LCME accreditation), Department of Medical Education, 3500 Camp Bowie Blvd., Fort Worth, TX, 76107, USA
| | - Gregory Dussor
- School of Behavioral and Brain Sciences, The University of Texas at Dallas, 800 West Campbell Road, BSB-14, Richardson, TX, 75080, USA.
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Moy JK, Khoutorsky A, Asiedu MN, Dussor G, Price TJ. eIF4E Phosphorylation Influences Bdnf mRNA Translation in Mouse Dorsal Root Ganglion Neurons. Front Cell Neurosci 2018; 12:29. [PMID: 29467623 PMCID: PMC5808250 DOI: 10.3389/fncel.2018.00029] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2017] [Accepted: 01/23/2018] [Indexed: 01/19/2023] Open
Abstract
Plasticity in dorsal root ganglion (DRG) neurons that promotes pain requires activity-dependent mRNA translation. Protein synthesis inhibitors block the ability of many pain-promoting molecules to enhance excitability in DRG neurons and attenuate behavioral signs of pain plasticity. In line with this, we have recently shown that phosphorylation of the 5′ cap-binding protein, eIF4E, plays a pivotal role in plasticity of DRG nociceptors in models of hyperalgesic priming. However, mRNA targets of eIF4E phosphorylation have not been elucidated in the DRG. Brain-derived neurotrophic factor (BDNF) signaling from nociceptors in the DRG to spinal dorsal horn neurons is an important mediator of hyperalgesic priming. Regulatory mechanisms that promote pain plasticity via controlling BDNF expression that is involved in promoting pain plasticity have not been identified. We show that phosphorylation of eIF4E is paramount for Bdnf mRNA translation in the DRG. Bdnf mRNA translation is reduced in mice lacking eIF4E phosphorylation (eIF4ES209A) and pro-nociceptive factors fail to increase BDNF protein levels in the DRGs of these mice despite robust upregulation of Bdnf-201 mRNA levels. Importantly, bypassing the DRG by giving intrathecal injection of BDNF in eIF4ES209A mice creates a strong hyperalgesic priming response that is normally absent or reduced in these mice. We conclude that eIF4E phosphorylation-mediated translational control of BDNF expression is a key mechanism for nociceptor plasticity leading to hyperalgesic priming.
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Affiliation(s)
- Jamie K Moy
- School of Behavioral and Brain Sciences, University of Texas at Dallas, Richardson, TX, United States.,Department of Pharmacology, University of Arizona, Tucson, AZ, United States
| | - Arkady Khoutorsky
- Department of Anesthesia, McGill University, Montréal, QC, Canada.,Alan Edwards Centre for Research on Pain, McGill University, Montréal, QC, Canada
| | - Marina N Asiedu
- School of Behavioral and Brain Sciences, University of Texas at Dallas, Richardson, TX, United States.,Department of Pharmacology, University of Arizona, Tucson, AZ, United States
| | - Gregory Dussor
- School of Behavioral and Brain Sciences, University of Texas at Dallas, Richardson, TX, United States.,Department of Pharmacology, University of Arizona, Tucson, AZ, United States
| | - Theodore J Price
- School of Behavioral and Brain Sciences, University of Texas at Dallas, Richardson, TX, United States.,Department of Pharmacology, University of Arizona, Tucson, AZ, United States
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56
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Sandweiss AJ, Cottier KE, McIntosh MI, Dussor G, Davis TP, Vanderah TW, Largent-Milnes TM. 17-β-Estradiol induces spreading depression and pain behavior in alert female rats. Oncotarget 2017; 8:114109-114122. [PMID: 29371973 PMCID: PMC5768390 DOI: 10.18632/oncotarget.23141] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2017] [Accepted: 11/26/2017] [Indexed: 01/17/2023] Open
Abstract
AIMS Test the putative contribution of 17-β-estradiol in the development of spreading depression (SD) events and head pain in awake, non-restrained rats. MAIN METHODS Female, Sprague-Dawley rats were intact or underwent ovariectomy followed one week later by surgery to place electrodes onto the dura to detect epidural electroencephalographic activity (dEEG). dEEG activity was recorded two days later for 12 hours after systemic administration of 17-β-estradiol (180 μg/kg, i.p.). A separate set of rats were observed for changes in exploratory, ambulatory, fine, and rearing behaviors; periorbital allodynia was also assessed. KEY FINDINGS A bolus of 17-β-estradiol significantly elevated serum estrogen levels, increased SD episodes over a 12-hour recording period and decreased rearing behaviors in ovariectomized rats. Pre-administration of ICI 182,780, an estrogen receptor antagonist, blocked 17-β-estradiol-evoked SD events and pain behaviors; similar results were observed when the antimigraine therapeutic sumatriptan was used. SIGNIFICANCE These data indicate that an estrogen receptor-mediated mechanism contributes to SD events in ovariectomized rats and pain behaviors in both ovariectomized -and intact- rats. This suggests that estrogen plays a different role in each phenomenon of migraine where intense fluctuations in concentration may influence SD susceptibility. This is the first study to relate estrogen peaks to SD development and pain behaviors in awake, freely moving female rats, establishing a framework for future preclinical migraine studies.
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Affiliation(s)
- Alexander J. Sandweiss
- Department of Pharmacology, College of Medicine, University of Arizona, Tucson, Arizona 85724, USA
| | - Karissa E. Cottier
- Department of Pharmacology, College of Medicine, University of Arizona, Tucson, Arizona 85724, USA
| | - Mary I. McIntosh
- Department of Pharmacology, College of Medicine, University of Arizona, Tucson, Arizona 85724, USA
| | - Gregory Dussor
- School of Behavioral and Brain Sciences, University of Texas at Dallas, Richardson, Texas 75080, USA
| | - Thomas P. Davis
- Department of Pharmacology, College of Medicine, University of Arizona, Tucson, Arizona 85724, USA
| | - Todd W. Vanderah
- Department of Pharmacology, College of Medicine, University of Arizona, Tucson, Arizona 85724, USA
| | - Tally M. Largent-Milnes
- Department of Pharmacology, College of Medicine, University of Arizona, Tucson, Arizona 85724, USA
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57
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Price TJ, Das V, Dussor G. Adenosine Monophosphate-activated Protein Kinase (AMPK) Activators For the Prevention, Treatment and Potential Reversal of Pathological Pain. Curr Drug Targets 2017; 17:908-20. [PMID: 26521775 DOI: 10.2174/1389450116666151102095046] [Citation(s) in RCA: 47] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2014] [Revised: 10/20/2015] [Accepted: 10/29/2015] [Indexed: 12/23/2022]
Abstract
Pathological pain is an enormous medical problem that places a significant burden on patients and can result from an injury that has long since healed or be due to an unidentifiable cause. Although treatments exist, they often either lack efficacy or have intolerable side effects. More importantly, they do not reverse the changes in the nervous system mediating pathological pain, and thus symptoms often return when therapies are discontinued. Consequently, novel therapies are urgently needed that have both improved efficacy and disease-modifying properties. Here we highlight an emerging target for novel pain therapies, adenosine monophosphate-activated protein kinase (AMPK). AMPK is capable of regulating a variety of cellular processes including protein translation, activity of other kinases, and mitochondrial metabolism, many of which are thought to contribute to pathological pain. Consistent with these properties, preclinical studies show positive, and in some cases disease-modifying effects of either pharmacological activation or genetic regulation of AMPK in models of nerve injury, chemotherapy-induced peripheral neuropathy (CIPN), postsurgical pain, inflammatory pain, and diabetic neuropathy. Given the AMPK-activating ability of metformin, a widely prescribed and well-tolerated drug, these preclinical studies provide a strong rationale for both retrospective and prospective human pain trials with this drug. They also argue for the development of novel AMPK activators, whether orthosteric, allosteric, or modulators of events upstream of the kinase. Together, this review will present the case for AMPK as a novel therapeutic target for pain and will discuss future challenges in the path toward development of AMPK-based pain therapeutics.
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Affiliation(s)
- Theodore J Price
- School of Behavioral and Brain Sciences, University of Texas at Dallas, JO 4.212 800 W Campbell Rd, Richardson TX 75080, USA.
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58
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Vega CB, Quigley L, Patel M, Price T, Arkopian A, Dussor G. (137) Meningeal application of prolactin and CGRP produces female specific migraine-related behavior in rodents. The Journal of Pain 2017. [DOI: 10.1016/j.jpain.2017.02.043] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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59
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Asiedu MN, Han C, Dib-Hajj SD, Waxman SG, Price TJ, Dussor G. The AMPK Activator A769662 Blocks Voltage-Gated Sodium Channels: Discovery of a Novel Pharmacophore with Potential Utility for Analgesic Development. PLoS One 2017; 12:e0169882. [PMID: 28118359 PMCID: PMC5261566 DOI: 10.1371/journal.pone.0169882] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2016] [Accepted: 12/23/2016] [Indexed: 12/12/2022] Open
Abstract
Voltage-gated sodium channels (VGSC) regulate neuronal excitability by governing action potential (AP) generation and propagation. Recent studies have revealed that AMP-activated protein kinase (AMPK) activators decrease sensory neuron excitability, potentially by preventing sodium (Na+) channel phosphorylation by kinases such as ERK or via modulation of translation regulation pathways. The direct positive allosteric modulator A769662 displays substantially greater efficacy than other AMPK activators in decreasing sensory neuron excitability suggesting additional mechanisms of action. Here, we show that A769662 acutely inhibits AP firing stimulated by ramp current injection in rat trigeminal ganglion (TG) neurons. PT1, a structurally dissimilar AMPK activator that reduces nerve growth factor (NGF) -induced hyperexcitability, has no influence on AP firing in TG neurons upon acute application. In voltage-clamp recordings, application of A769662 reduces VGSC current amplitudes. These findings, based on acute A769662 application, suggest a direct channel blocking effect. Indeed, A769662 dose-dependently blocks VGSC in rat TG neurons and in Nav1.7-transfected cells with an IC50 of ~ 10 μM. A769662 neither displayed use-dependent inhibition nor interacted with the local anesthetic (LA) binding site. Popliteal fossa administration of A769662 decreased noxious thermal responses with a peak effect at 5 mins demonstrating an analgesic effect. These data indicate that in addition to AMPK activation, A769662 acts as a direct blocker/modulator of VGSCs, a potential mechanism enhancing the analgesic property of this compound.
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Affiliation(s)
- Marina N. Asiedu
- University of Arizona, Department of Pharmacology, Tucson, Arizona, United States of America
- University of Texas at Dallas, School of Behavioral and Brain Sciences, Richardson, Texas, United States of America
| | - Chongyang Han
- Yale School of Medicine, Department of Neurology, Center for Neuroscience and Regeneration Research, and Veterans Administration Connecticut Healthcare System, Rehabilitation Research Center, West Haven, Connecticut, United States of America
| | - Sulayman D. Dib-Hajj
- Yale School of Medicine, Department of Neurology, Center for Neuroscience and Regeneration Research, and Veterans Administration Connecticut Healthcare System, Rehabilitation Research Center, West Haven, Connecticut, United States of America
| | - Stephen G. Waxman
- Yale School of Medicine, Department of Neurology, Center for Neuroscience and Regeneration Research, and Veterans Administration Connecticut Healthcare System, Rehabilitation Research Center, West Haven, Connecticut, United States of America
| | - Theodore J. Price
- University of Arizona, Department of Pharmacology, Tucson, Arizona, United States of America
- University of Texas at Dallas, School of Behavioral and Brain Sciences, Richardson, Texas, United States of America
| | - Gregory Dussor
- University of Arizona, Department of Pharmacology, Tucson, Arizona, United States of America
- University of Texas at Dallas, School of Behavioral and Brain Sciences, Richardson, Texas, United States of America
- * E-mail:
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60
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Abstract
Migraine is the third most common disease worldwide, the most common neurological disorder, and one of the most common pain conditions. Despite its prevalence, the basic physiology and underlying mechanisms contributing to the development of migraine are still poorly understood and development of new therapeutic targets is long overdue. Until recently, the major contributing pathophysiological event thought to initiate migraine was cerebral and meningeal arterial vasodilation. However, the role of vasodilation in migraine is unclear and recent findings challenge its necessity. While vasodilation itself may not contribute to migraine, it remains possible that vessels play a role in migraine pathophysiology in the absence of vasodilation. Blood vessels consist of a variety of cell types that both release and respond to numerous mediators including growth factors, cytokines, adenosine triphosphate (ATP), and nitric oxide (NO). Many of these mediators have actions on neurons that can contribute to migraine. Conversely, neurons release factors such as norepinephrine and calcitonin gene-related peptide (CGRP) that act on cells native to blood vessels. Both normal and pathological events occurring within and between vascular cells could thus mediate bi-directional communication between vessels and the nervous system, without the need for changes in vascular tone. This review will discuss the potential contribution of the vasculature, specifically endothelial cells, to current neuronal mechanisms hypothesized to play a role in migraine. Hypothalamic activity, cortical spreading depression (CSD), and dural afferent input from the cranial meninges will be reviewed with a focus on how these mechanisms can influence or be impacted by blood vessels. Together, the data discussed will provide a framework by which vessels can be viewed as important potential contributors to migraine pathophysiology, even in light of the current uncertainty over the role of vasodilation in this disorder.
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Affiliation(s)
- Blaine Jacobs
- Behavioral and Brain Sciences, The University of Texas at Dallas, 800 West Campbell Road, Richardson, TX 75080, United States
| | - Gregory Dussor
- Behavioral and Brain Sciences, The University of Texas at Dallas, 800 West Campbell Road, Richardson, TX 75080, United States.
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Srivastava S, Potla S, Torck A, Zhang M, Dussor G, Ray P, Price T. (278) A potential role for eIF4A in regulation of nociceptor plasticity: a motif-based genome-wide search for eIF4A targets. The Journal of Pain 2016. [DOI: 10.1016/j.jpain.2016.01.184] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Burgos-Vega CC, Ahn DDU, Bischoff C, Wang W, Horne D, Wang J, Gavva N, Dussor G. Meningeal transient receptor potential channel M8 activation causes cutaneous facial and hindpaw allodynia in a preclinical rodent model of headache. Cephalalgia 2016; 36:185-93. [PMID: 25944818 PMCID: PMC4635063 DOI: 10.1177/0333102415584313] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2014] [Accepted: 04/05/2015] [Indexed: 01/17/2023]
Abstract
BACKGROUND Migraine headache is a neurological disorder affecting millions worldwide. However, little is known about the mechanisms contributing to migraine. Recent genome-wide association studies have found single nucleotide polymorphisms in the gene encoding transient receptor potential channel M8. Transient receptor potential channel M8 is generally known as a cold receptor but it has been implicated in pain signaling and may play a role in migraine pain. METHODS In order to investigate whether transient receptor potential channel M8 may contribute to the pain of migraine, the transient receptor potential channel M8 activator icilin was applied to the dura mater using a rat behavioral model of headache. Cutaneous allodynia was measured for 5 hours using Von Frey filaments. RESULTS Dural application of icilin produced cutaneous facial and hind paw allodynia that was attenuated by systemic pretreatment with the transient receptor potential channel M8-selective antagonist AMG1161 (10 mg/kg p.o.). Further, the anti-migraine agent sumatriptan (0.6 mg/kg s.c.) or the non-selective NOS inhibitor L-NAME (20 mg/kg i.p.) also attenuated allodynia when given as a pretreatment. CONCLUSIONS These data indicate that transient receptor potential channel M8 activation in the meninges produces behaviors in rats that are consistent with migraine and that are sensitive to pharmacological mechanisms known to have efficacy for migraine in humans. The findings suggest that activation of meningeal transient receptor potential channel M8 may contribute to the pain of migraine.
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Affiliation(s)
| | | | | | | | | | | | | | - Gregory Dussor
- Department of Pharmacology, University of Arizona, USA School of Behavioral and Brain Sciences, University of Texas at Dallas, USA
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63
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Abstract
Migraine is the most common neurological disorder. Attacks are complex and consist of multiple phases but are most commonly characterized by intense, unilateral, throbbing headache. The pathophysiology contributing to migraine is poorly understood and the disorder is not well managed with currently available therapeutics, often rendering patients disabled during attacks. The mechanisms most likely to contribute to the pain phase of migraine require activation of trigeminal afferent signaling from the cranial meninges and subsequent relay of nociceptive information into the central nervous system in a region of the dorsal brainstem known as the trigeminal nucleus caudalis. Events leading to activation of meningeal afferents are unclear, but nerve endings within this tissue are mechanosensitive and also express a variety of ion channels including acid-sensing ion channels and transient receptor-potential channels. These properties may provide clues into the pathophysiology of migraine by suggesting that decreased extracellular pH and environmental irritant exposure in the meninges contributes to headache. Neuroplasticity is also likely to play a role in migraine given that attacks are triggered by routine events that are typically nonnoxious in healthy patients and clear evidence of sensitization occurs during an attack. Where and how plasticity develops is also not clear but may include events directly on the afferents and/or within the TNC. Among the mediators potentially contributing to plasticity, calcitonin gene-related peptide has received the most attention within the migraine field but other mechanisms may also contribute. Ultimately, greater understanding of the molecules and mechanisms contributing to migraine will undoubtedly lead to better therapeutics and relief for the large number of patients across the globe who suffer from this highly disabling neurological disorder.
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Affiliation(s)
- Carolina Burgos-Vega
- Behavioral and Brain Sciences, The University of Texas at Dallas, Richardson, Texas, USA
| | - Jamie Moy
- Behavioral and Brain Sciences, The University of Texas at Dallas, Richardson, Texas, USA
| | - Gregory Dussor
- Behavioral and Brain Sciences, The University of Texas at Dallas, Richardson, Texas, USA.
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Wei X, Yan J, Tillu D, Asiedu M, Weinstein N, Melemedjian O, Price T, Dussor G. Meningeal norepinephrine produces headache behaviors in rats via actions both on dural afferents and fibroblasts. Cephalalgia 2015; 35:1054-64. [PMID: 25601915 DOI: 10.1177/0333102414566861] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2014] [Accepted: 12/06/2014] [Indexed: 12/20/2022]
Abstract
BACKGROUND Stress is commonly reported to contribute to migraine although mechanisms by which this may occur are not fully known. The purpose of these studies was to examine whether norepinephrine (NE), the primary sympathetic efferent transmitter, acts on processes in the meninges that may contribute to the pain of migraine. METHODS NE was applied to rat dura using a behavioral model of headache. Primary cultures of rat trigeminal ganglia retrogradely labeled from the dura mater and of rat dural fibroblasts were prepared. Patch-clamp electrophysiology, Western blot, and ELISA were performed to examine the effects of NE. Conditioned media from NE-treated fibroblast cultures was applied to the dura using the behavioral headache model. RESULTS Dural injection both of NE and media from NE-stimulated fibroblasts caused cutaneous facial and hindpaw allodynia in awake rats. NE application to cultured dural afferents increased action potential firing in response to current injections. Application of NE to dural fibroblasts increased phosphorylation of ERK and caused the release of interleukin-6 (IL-6). CONCLUSIONS These data demonstrate that NE can contribute to pro-nociceptive signaling from the meninges via actions on dural afferents and dural fibroblasts. Together, these actions of NE may contribute to the headache phase of migraine.
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Affiliation(s)
- Xiaomei Wei
- Department of Pharmacology, The University of Arizona College of Medicine, USA
| | - Jin Yan
- Department of Pharmacology, The University of Arizona College of Medicine, USA
| | - Dipti Tillu
- Department of Pharmacology, The University of Arizona College of Medicine, USA
| | - Marina Asiedu
- Department of Pharmacology, The University of Arizona College of Medicine, USA School of Behavioral and Brain Sciences, The University of Texas at Dallas, USA
| | - Nicole Weinstein
- Department of Pharmacology, The University of Arizona College of Medicine, USA
| | - Ohannes Melemedjian
- Department of Pharmacology, The University of Arizona College of Medicine, USA
| | - Theodore Price
- Department of Pharmacology, The University of Arizona College of Medicine, USA School of Behavioral and Brain Sciences, The University of Texas at Dallas, USA
| | - Gregory Dussor
- Department of Pharmacology, The University of Arizona College of Medicine, USA School of Behavioral and Brain Sciences, The University of Texas at Dallas, USA
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Abstract
Following injury, nociceptive systems become sensitized, leading to heightened pain perception. The evolutionary reason for this phenomenon has been hard to pinpoint. A study in squid now suggests that nociceptive sensitization enhances survival from predators.
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Affiliation(s)
- Theodore J Price
- University of Texas at Dallas, School of Behavior and Brain Sciences, Dallas, TX, USA.
| | - Gregory Dussor
- University of Texas at Dallas, School of Behavior and Brain Sciences, Dallas, TX, USA; University of Arizona School of Medicine, Department of Pharmacology, Tucson, AZ, USA.
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66
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Abstract
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Migraine is increasingly understood
to be a disorder of the brain.
In susceptible individuals, a variety of “triggers”
may influence altered central excitability, resulting in the activation
and sensitization of trigeminal nociceptive afferents surrounding
blood vessels (i.e., the trigeminovascular system), leading to migraine
pain. Transient receptor potential (TRP) channels are expressed in
a subset of dural afferents, including those containing calcitonin
gene related peptide (CGRP). Activation of TRP channels promotes excitation
of nociceptive afferent fibers and potentially lead to pain. In addition
to pain, allodynia to mechanical and cold stimuli can result from
sensitization of both peripheral afferents and of central pain pathways.
TRP channels respond to a variety of endogenous conditions including
chemical mediators and low pH. These channels can be activated by
exogenous stimuli including a wide range of chemical and environmental
irritants, some of which have been demonstrated to trigger migraine
in humans. Activation of TRP channels can elicit CGRP release, and
blocking the effects of CGRP through receptor antagonism or antibody
strategies has been demonstrated to be effective in the treatment
of migraine. Identification of approaches that can prevent activation
of TRP channels provides an additional novel strategy for discovery
of migraine therapeutics.
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Affiliation(s)
- Gregory Dussor
- School
of Behavioral and Brain Sciences, University of Texas at Dallas, Dallas, Texas 75080, United States
| | - J. Yan
- Department
of Pharmacology, University of Washington, Seattle, Washington 98195, United States
| | - Jennifer Y. Xie
- Department
of Pharmacology, University of Arizona College of Medicine, Tucson, Arizona 85724, United States
| | - Michael H. Ossipov
- Department
of Pharmacology, University of Arizona College of Medicine, Tucson, Arizona 85724, United States
| | - David W. Dodick
- Department
of Neurology, Mayo Clinic Arizona, Phoenix, Arizona 85054, United States
| | - Frank Porreca
- Department
of Pharmacology, University of Arizona College of Medicine, Tucson, Arizona 85724, United States
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67
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Melemedjian OK, Tillu DV, Moy JK, Asiedu MN, Mandell EK, Ghosh S, Dussor G, Price TJ. Local translation and retrograde axonal transport of CREB regulates IL-6-induced nociceptive plasticity. Mol Pain 2014; 10:45. [PMID: 24993495 PMCID: PMC4091745 DOI: 10.1186/1744-8069-10-45] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2014] [Accepted: 07/01/2014] [Indexed: 11/10/2022] Open
Abstract
Transcriptional regulation of genes by cyclic AMP response element binding protein (CREB) is essential for the maintenance of long-term memory. Moreover, retrograde axonal trafficking of CREB in response to nerve growth factor (NGF) is critical for the survival of developing primary sensory neurons. We have previously demonstrated that hindpaw injection of interleukin-6 (IL-6) induces mechanical hypersensitivity and hyperalgesic priming that is prevented by the local injection of protein synthesis inhibitors. However, proteins that are locally synthesized that might lead to this effect have not been identified. We hypothesized that retrograde axonal trafficking of nascently synthesized CREB might link local, activity-dependent translation to nociceptive plasticity. To test this hypothesis, we determined if IL-6 enhances the expression of CREB and if it subsequently undergoes retrograde axonal transport. IL-6 treatment of sensory neurons in vitro caused an increase in CREB protein and in vivo treatment evoked an increase in CREB in the sciatic nerve consistent with retrograde transport. Importantly, co-injection of IL-6 with the methionine analogue azido-homoalanine (AHA), to assess nascently synthesized proteins, revealed an increase in CREB containing AHA in the sciatic nerve 2 hrs post injection, indicating retrograde transport of nascently synthesized CREB. Behaviorally, blockade of retrograde transport by disruption of microtubules or inhibition of dynein or intrathecal injection of cAMP response element (CRE) consensus sequence DNA oligonucleotides, which act as decoys for CREB DNA binding, prevented the development of IL-6-induced mechanical hypersensitivity and hyperalgesic priming. Consistent with previous studies in inflammatory models, intraplantar IL-6 enhanced the expression of BDNF in dorsal root ganglion (DRG). This effect was blocked by inhibition of retrograde axonal transport and by intrathecal CRE oligonucleotides. Collectively, these findings point to a novel mechanism of axonal translation and retrograde trafficking linking locally-generated signals to long-term nociceptive sensitization.
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Affiliation(s)
| | | | | | | | | | | | | | - Theodore J Price
- Department of Pharmacology, The University of Arizona School of Medicine, Tucson, USA.
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68
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Abstract
Migraine is one of the most common neurological disorders. Despite its prevalence, the basic physiology of the molecules and mechanisms that contribute to migraine headache is still poorly understood, making the discovery of more effective treatments extremely difficult. The consistent presence of head-specific pain during migraine suggests an important role for activation of the peripheral nociceptors localized to the head. Accordingly, this review will cover the current understanding of the biological mechanisms leading to episodic activation and sensitization of the trigeminovascular pain pathway, focusing on recent advances regarding activation and modulation of ion channels.
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Affiliation(s)
- Jin Yan
- Department of Pharmacology, University of Washington, Seattle, WA, USA
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69
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Yan J, Wei X, Bischoff C, Edelmayer RM, Dussor G. pH-evoked dural afferent signaling is mediated by ASIC3 and is sensitized by mast cell mediators. Headache 2013; 53:1250-61. [PMID: 23808707 DOI: 10.1111/head.12152] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/08/2013] [Indexed: 11/29/2022]
Abstract
BACKGROUND Prior studies have shown that decreased meningeal pH activates dural afferents via opening of acid-sensing ion channels (ASICs), suggesting one pathophysiological mechanism for the generation of headaches. The studies described here further examined the ASIC subtype mediating pH-induced dural-afferent activation and examined whether sensitization influences pH responses. OBJECTIVE Given the potential importance of meningeal mast cells to headache, the goal of this study was to evaluate dural afferent responses to pH following sensitization with mast cell mediators. METHODS Cutaneous allodynia was measured in rats following stimulation of the dura with decreased pH alone or in combination with mast cell mediators. Trigeminal ganglion neurons retrogradely labeled from the dura were stained with an ASIC3 antibody using immunohistochemistry. Current and action potentials evoked by changes in pH alone or in combination with mast cell mediators were measured in retrogradely labeled dural afferents using patch-clamp electrophysiology. RESULTS pH-sensitive dural afferents generated currents in response to the ASIC3 activator 2-guanidine-4-methylquinazoline (GMQ), approximately 80% of these neurons express ASIC3 protein, and pH-evoked behavioral responses were inhibited by the ASIC3 blocker APETx2. Following exposure to mast cell mediators, dural afferents exhibited increased pH-evoked excitability, and cutaneous allodynia was observed at higher pH than with pH stimuli alone. CONCLUSIONS These data indicate that the predominant ASIC subtype responding to decreased meningeal pH is ASIC3. Additionally, they demonstrate that in the presence of inflammation, dural afferents respond to even smaller decreases in pH providing further support for the ability of small pH changes within the meninges to initiate afferent input leading to headache.
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Affiliation(s)
- Jin Yan
- Department of Pharmacology, University of Washington, Seattle, WA, USA
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70
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Melemedjian OK, Khoutorsky A, Sorge RE, Yan J, Asiedu MN, Valdez A, Ghosh S, Dussor G, Mogil JS, Sonenberg N, Price TJ. mTORC1 inhibition induces pain via IRS-1-dependent feedback activation of ERK. Pain 2013; 154:1080-91. [PMID: 23607966 DOI: 10.1016/j.pain.2013.03.021] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2012] [Revised: 03/05/2013] [Accepted: 03/12/2013] [Indexed: 02/07/2023]
Abstract
Mammalian target of rapamycin complex 1 (mTORC1) inhibitors are extensively used as immunosuppressants to prevent transplant rejection and in treatment of certain cancers. In patients, chronic treatment with rapamycin or its analogues (rapalogues) has been reported to lead to sensory hypersensitivity and pain conditions via an unknown mechanism. Here, we show that pharmacological or genetic inhibition of mTORC1 activates the extracellular signal-regulated kinase (ERK) pathway in sensory neurons via suppression of S6K1 to insulin receptor substrate 1 negative feedback loop. As a result, increased ERK activity induces sensory neuron sensitization, mechanical hypersensitivity, and spontaneous pain. The clinically available adenosine monophosphate-activated protein kinase activator, metformin, which is an antidiabetic drug, prevents rapamycin-induced ERK activation and the development of mechanical hypersensitivity and spontaneous pain. Taken together, our findings demonstrate that activation of the ERK pathway in sensory neurons as a consequence of mTORC1 inhibition leads to the development of pain. Importantly, this effect is abolished by co-treatment with metformin, thus providing a potential treatment option for rapalogue-evoked pain. Our findings highlight the physiological relevance of feedback signaling through mTORC1 inhibition and have important implications for development of pain therapeutics that target the mTOR pathway.
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71
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Edelmayer RM, Le LN, Yan J, Wei X, Nassini R, Materazzi S, Preti D, Appendino G, Geppetti P, Dodick DW, Vanderah TW, Porreca F, Dussor G. Activation of TRPA1 on dural afferents: a potential mechanism of headache pain. Pain 2012; 153:1949-1958. [PMID: 22809691 DOI: 10.1016/j.pain.2012.06.012] [Citation(s) in RCA: 98] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2012] [Revised: 05/30/2012] [Accepted: 06/12/2012] [Indexed: 01/07/2023]
Abstract
Activation of transient receptor potential ankyrin-1 (TRPA1) on meningeal nerve endings has been suggested to contribute to environmental irritant-induced headache, but this channel may also contribute to other forms of headache, such as migraine. The preclinical studies described here examined functional expression of TRPA1 on dural afferents and investigated whether activation of TRPA1 contributes to headache-like behaviors. Whole-cell patch-clamp recordings were performed in vitro with 2 TRPA1 agonists, mustard oil (MO), and the environmental irritant umbellulone (UMB) on dural-projecting trigeminal ganglion neurons. Application of MO and UMB to dural afferents produced TRPA1-like currents in approximately 42% and 38% of cells, respectively. By means of an established in vivo behavioral model of migraine-related allodynia, dural application of MO and UMB produced robust time-related tactile facial and hind paw allodynia that was attenuated by pretreatment with the TRPA1 antagonist HC-030031. Additionally, MO or UMB were applied to the dura, and exploratory activity was monitored for 30min with an automated open-field activity chamber. Dural MO and UMB decreased the number of vertical rearing episodes and the time spent rearing in comparison to vehicle-treated animals. This change in activity was prevented in rats pretreated with HC-030031 as well as sumatriptan, a clinically effective antimigraine agent. These data indicate that TRPA1 is expressed on a substantial fraction of dural afferents, and activation of meningeal TRPA1 produces behaviors consistent with those observed in patients during migraine attacks. Further, they suggest that activation of meningeal TRPA1 via endogenous or exogenous mechanisms can lead to afferent signaling and headache.
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Affiliation(s)
- Rebecca M Edelmayer
- Department of Pharmacology, College of Medicine, University of Arizona, Tucson, AZ, USA Department of Preclinical and Clinical Pharmacology and Headache Center, University of Florence, Florence, Italy Department of Pharmaceutical Chemistry, University of Ferrara, Ferrara, Italy Department of Chemical, Alimentary, Pharmaceutical and Pharmacological Sciences, University of Eastern Piedmont, Novara, Italy Department of Neurology, Mayo Clinic Arizona, Scottsdale, AZ, USA
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72
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Patwardhan A, Edelmayer R, Annabi E, Price T, Malan P, Dussor G. Receptor specificity defines algogenic properties of propofol and fospropofol. Anesth Analg 2012; 115:837-40. [PMID: 22584560 DOI: 10.1213/ane.0b013e318258b9db] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
BACKGROUND Propofol-evoked injection site pain is not observed with fospropofol. We hypothesized that unlike propofol, fospropofol does not activate the irritant receptor, transient receptor potential 1 (TRPA1). METHODS We tested the hypothesis using electrophysiology and behavioral studies. RESULTS Our data demonstrate that propofol (100 μM) evokes an inward current only in TRPA1-expressing neurons. However, fospropofol (100 μM and 1 mM) is unable to evoke depolarizing currents in either TRPA1-positive or TRPA1-negative neurons. Both propofol and fospropofol produced general anesthesia. CONCLUSIONS The lack of algogenic activity in fospropofol is most likely the result of its inability to activate TRPA1 on nociceptors.
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Affiliation(s)
- Amol Patwardhan
- Department of Anesthesiology, University of Arizona Health Sciences Center, Tucson, AZ 85724, USA
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73
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Yan J, Melemedjian OK, Price TJ, Dussor G. Sensitization of dural afferents underlies migraine-related behavior following meningeal application of interleukin-6 (IL-6). Mol Pain 2012; 8:6. [PMID: 22273495 PMCID: PMC3274468 DOI: 10.1186/1744-8069-8-6] [Citation(s) in RCA: 96] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2011] [Accepted: 01/24/2012] [Indexed: 01/11/2023] Open
Abstract
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.
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Affiliation(s)
- Jin Yan
- Department of Pharmacology, University of Arizona College of Medicine, 1501 N Campbell Ave, PO Box 245050, Tucson, AZ 85724, USA
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74
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Tillu DV, Melemedjian OK, Asiedu MN, Qu N, De Felice M, Dussor G, Price TJ. Resveratrol engages AMPK to attenuate ERK and mTOR signaling in sensory neurons and inhibits incision-induced acute and chronic pain. Mol Pain 2012; 8:5. [PMID: 22269797 PMCID: PMC3284441 DOI: 10.1186/1744-8069-8-5] [Citation(s) in RCA: 129] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2011] [Accepted: 01/23/2012] [Indexed: 11/10/2022] Open
Abstract
Background Despite advances in our understanding of basic mechanisms driving post-surgical pain, treating incision-induced pain remains a major clinical challenge. Moreover, surgery has been implicated as a major cause of chronic pain conditions. Hence, more efficacious treatments are needed to inhibit incision-induced pain and prevent the transition to chronic pain following surgery. We reasoned that activators of AMP-activated protein kinase (AMPK) may represent a novel treatment avenue for the local treatment of incision-induced pain because AMPK activators inhibit ERK and mTOR signaling, two important pathways involved in the sensitization of peripheral nociceptors. Results To test this hypothesis we used a potent and efficacious activator of AMPK, resveratrol. Our results demonstrate that resveratrol profoundly inhibits ERK and mTOR signaling in sensory neurons in a time- and concentration-dependent fashion and that these effects are mediated by AMPK activation and independent of sirtuin activity. Interleukin-6 (IL-6) is thought to play an important role in incision-induced pain and resveratrol potently inhibited IL-6-mediated signaling to ERK in sensory neurons and blocked IL-6-mediated allodynia in vivo through a local mechanism of action. Using a model of incision-induced allodynia in mice, we further demonstrate that local injection of resveratrol around the surgical wound strongly attenuates incision-induced allodynia. Intraplantar IL-6 injection and plantar incision induces persistent nociceptive sensitization to PGE2 injection into the affected paw after the resolution of allodynia to the initial stimulus. We further show that resveratrol treatment at the time of IL-6 injection or plantar incision completely blocks the development of persistent nociceptive sensitization consistent with the blockade of a transition to a chronic pain state by resveratrol treatment. Conclusions These results highlight the importance of signaling to translation control in peripheral sensitization of nociceptors and provide further evidence for activation of AMPK as a novel treatment avenue for acute and chronic pain states.
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Affiliation(s)
- Dipti V Tillu
- Department of Pharmacology, University of Arizona, 1501 N Campbell Ave, PO BOX 245050, Tucson, AZ 85724, USA
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75
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Wei X, Edelmayer RM, Yan J, Dussor G. Activation of TRPV4 on dural afferents produces headache-related behavior in a preclinical rat model. Cephalalgia 2011; 31:1595-600. [PMID: 22049072 DOI: 10.1177/0333102411427600] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
BACKGROUND The mechanisms contributing to the pain of migraine are poorly understood although activation of afferent nociceptors in the trigeminovascular system has been proposed as a key event. Prior studies have shown that dural-afferent nociceptors are sensitive to both osmotic and mechanical stimuli. Based on the sensitivity to these stimuli we hypothesized that dural afferents express the osmo/mechano-sensitive channel transient receptor-potential vanilloid 4 (TRPV4). METHODS These studies used in vitro patch-clamp electrophysiology of trigeminal neurons retrogradely labeled from the dura to examine the functional expression of TRPV4. Additionally, we used a rat headache model in which facial/hind paw allodynia following dural stimulation is measured to determine whether activation of meningeal TRPV4 produces responses consistent with migraine. RESULTS These studies found that 56% and 49% of identified dural afferents generate currents in response to hypotonic solutions and 4α-PDD, respectively. The response to these stimuli indicates that dural afferents express TRPV4. Activation of meningeal TPRV4 using hypotonic solution or 4α-PDD in vivo resulted in both facial and hind paw allodynia that was blocked by the TRPV4 antagonist RN1734. CONCLUSION These data indicate that activation of TRPV4 within the meninges produces afferent nociceptive signaling from the head that may contribute to migraine headache.
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Affiliation(s)
- Xiaomei Wei
- University of Arizona College of Medicine, Tucson, AZ 85724, USA
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76
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Melemedjian OK, Asiedu MN, Tillu DV, Sanoja R, Yan J, Lark A, Khoutorsky A, Johnson J, Peebles KA, Lepow T, Sonenberg N, Dussor G, Price TJ. Targeting adenosine monophosphate-activated protein kinase (AMPK) in preclinical models reveals a potential mechanism for the treatment of neuropathic pain. Mol Pain 2011; 7:70. [PMID: 21936900 PMCID: PMC3186752 DOI: 10.1186/1744-8069-7-70] [Citation(s) in RCA: 173] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2011] [Accepted: 09/21/2011] [Indexed: 12/31/2022] Open
Abstract
Neuropathic pain is a debilitating clinical condition with few efficacious treatments, warranting development of novel therapeutics. We hypothesized that dysregulated translation regulation pathways may underlie neuropathic pain. Peripheral nerve injury induced reorganization of translation machinery in the peripheral nervous system of rats and mice, including enhanced mTOR and ERK activity, increased phosphorylation of mTOR and ERK downstream targets, augmented eIF4F complex formation and enhanced nascent protein synthesis. The AMP activated protein kinase (AMPK) activators, metformin and A769662, inhibited translation regulation signaling pathways, eIF4F complex formation, nascent protein synthesis in injured nerves and sodium channel-dependent excitability of sensory neurons resulting in a resolution of neuropathic allodynia. Therefore, injury-induced dysregulation of translation control underlies pathology leading to neuropathic pain and reveals AMPK as a novel therapeutic target for the potential treatment of neuropathic pain.
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Affiliation(s)
- Ohannes K Melemedjian
- Department of Pharmacology, University of Arizona, N Campbell Ave, Tucson, 85724, USA
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King T, Vera-Portocarrero L, Gutierrez T, Vanderah TW, Dussor G, Lai J, Fields HL, Porreca F. Erratum: Corrigendum: Unmasking the tonic-aversive state in neuropathic pain. Nat Neurosci 2010. [DOI: 10.1038/nn0810-1033b] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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78
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De Felice M, Ossipov MH, Wang R, Dussor G, Lai J, Meng ID, Chichorro J, Andrews JS, Rakhit S, Maddaford S, Dodick D, Porreca F. Triptan-induced enhancement of neuronal nitric oxide synthase in trigeminal ganglion dural afferents underlies increased responsiveness to potential migraine triggers. Brain 2010; 133:2475-88. [PMID: 20627971 DOI: 10.1093/brain/awq159] [Citation(s) in RCA: 90] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Migraine is a common neurological disorder often treated with triptans. Triptan overuse can lead to increased frequency of headache in some patients, a phenomenon termed medication overuse headache. Previous preclinical studies have demonstrated that repeated or sustained triptan administration for several days can elicit persistent neural adaptations in trigeminal ganglion cells innervating the dura, prominently characterized by increased labelling of neuronal profiles for calcitonin gene related peptide. Additionally, triptan administration elicited a behavioural syndrome of enhanced sensitivity to surrogate triggers of migraine that was maintained for weeks following discontinuation of drug, a phenomenon termed 'triptan-induced latent sensitization'. Here, we demonstrate that triptan administration elicits a long-lasting increase in identified rat trigeminal dural afferents labelled for neuronal nitric oxide synthase in the trigeminal ganglion. Cutaneous allodynia observed during the period of triptan administration was reversed by NXN-323, a selective inhibitor of neuronal nitric oxide synthase. Additionally, neuronal nitric oxide synthase inhibition prevented environmental stress-induced hypersensitivity in the post-triptan administration period. Co-administration of NXN-323 with sumatriptan over several days prevented the expression of allodynia and enhanced sensitivity to stress observed following latent sensitization, but not the triptan-induced increased labelling of neuronal nitric oxide synthase in dural afferents. Triptan administration thus promotes increased expression of neuronal nitric oxide synthase in dural afferents, which is critical for enhanced sensitivity to environmental stress. These data provide a biological basis for increased frequency of headache following triptans and highlight the potential clinical utility of neuronal nitric oxide synthase inhibition in preventing or treating medication overuse headache.
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Affiliation(s)
- Milena De Felice
- Department of Pharmacology, College of Medicine, University of Arizona, Tucson, AZ 85724, USA
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De Felice M, Ossipov MH, Wang R, Lai J, Chichorro J, Meng I, Dodick DW, Vanderah TW, Dussor G, Porreca F. Triptan-induced latent sensitization: a possible basis for medication overuse headache. Ann Neurol 2010; 67:325-37. [PMID: 20373344 DOI: 10.1002/ana.21897] [Citation(s) in RCA: 74] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
OBJECTIVE Identification of the neural mechanisms underlying medication overuse headache resulting from triptans. METHODS Triptans were administered systemically to rats by repeated intermittent injections or by continuous infusion over 6 days. Periorbital and hind paw sensory thresholds were measured to detect cutaneous allodynia. Immunofluorescent histochemistry was employed to detect changes in peptidic neurotransmitter expression in identified dural afferents. Enzyme-linked immunoabsorbent assay was used to measure calcitonin gene-related peptide (CGRP) levels in blood. RESULTS Sustained or repeated administration of triptans to rats elicited time-dependent and reversible cutaneous tactile allodynia that was maintained throughout and transiently after drug delivery. Triptan administration increased labeling for CGRP in identified trigeminal dural afferents that persisted long after discontinuation of triptan exposure. Two weeks after triptan exposure, when sensory thresholds returned to baseline levels, rats showed enhanced cutaneous allodynia and increased CGRP in the blood following challenge with a nitric oxide donor. Triptan treatment thus induces a state of latent sensitization characterized by persistent pronociceptive neural adaptations in dural afferents and enhanced responses to an established trigger of migraine headache in humans. INTERPRETATION Triptans represent the treatment of choice for moderate and severe migraine headaches. However, triptan overuse can lead to an increased frequency of migraine headache. Overuse of these medications could induce neural adaptations that result in a state of latent sensitization, which might increase sensitivity to migraine triggers. The latent sensitization could provide a mechanistic basis for the transformation of migraine to medication overuse headache.
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Affiliation(s)
- Milena De Felice
- Department of Pharmacology, University of Arizona College of Medicine, Tucson, AZ, USA
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80
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Jimenez-Andrade JM, Mantyh WG, Bloom AP, Xu H, Ferng AS, Dussor G, Vanderah TW, Mantyh PW. A phenotypically restricted set of primary afferent nerve fibers innervate the bone versus skin: therapeutic opportunity for treating skeletal pain. Bone 2010; 46:306-13. [PMID: 19766746 PMCID: PMC2852192 DOI: 10.1016/j.bone.2009.09.013] [Citation(s) in RCA: 109] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/27/2009] [Revised: 09/10/2009] [Accepted: 09/12/2009] [Indexed: 12/28/2022]
Abstract
Although musculoskeletal pain is one of the most common causes of chronic pain and physical disability in both developing and developed countries, relatively little is known about the nerve fibers and mechanisms that drive skeletal pain. Small diameter sensory nerve fibers, most of which are C-fiber nociceptors, can be separated into two broad populations: the peptide-rich and peptide-poor nerve fibers. Peptide-rich nerve fibers express substance P (SP) and calcitonin gene-related peptide (CGRP). In contrast, the peptide-poor nerve fibers bind to isolectin B4 (IB(4)) and express the purinergic receptor P(2)X(3) and Mas-related G protein-coupled receptor member d (Mrgprd). In the present report, we used mice in which the Mrgprd(+) nerve fibers express genetically encoded axonal tracers to determine the peptide-rich and peptide-poor sensory nerve fibers that innervate the glabrous skin of the hindpaw as compared to the bone marrow, mineralized bone and periosteum of the femur. Whereas the skin is richly innervated by CGRP(+), SP(+), P(2)X(3)(+) and Mrgprd(+) sensory nerve fibers, the bone marrow, mineralized bone and periosteum receive a significant innervation by SP(+) and CGRP(+), but not Mrgprd(+) and P(2)X(3)(+) nerve fibers. This lack of redundancy in the populations of C-fibers that innervate the bone may present a unique therapeutic opportunity for targeting skeletal pain as the peptide-rich and peptide-poor sensory nerve fibers generally express a different repertoire of receptors and channels to detect noxious stimuli. Thus, therapies that target the specific types of C-nerve fibers that innervate the bone may be uniquely effective in attenuating skeletal pain as compared to skin pain.
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Dussor G, Zylka MJ, Anderson DJ, McCleskey EW. Cutaneous sensory neurons expressing the Mrgprd receptor sense extracellular ATP and are putative nociceptors. J Neurophysiol 2008; 99:1581-9. [PMID: 18234974 DOI: 10.1152/jn.01396.2007] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Sensory neurons expressing the Mrgprd receptor are known to innervate the outermost living layer of the epidermis, the stratum granulosum. The sensory modality that these neurons signal and the stimulus that they respond to are not established, although immunocytochemical data suggest they could be nonpeptidergic nociceptors. Using patch clamp of dissociated mouse dorsal root ganglion (DRG) neurons, the present study demonstrates that Mrgprd+ neurons have several properties typical of nociceptors: long-duration action potentials, TTX-resistant Na(+) current, and Ca(2+) currents that are inhibited by mu opioids. Remarkably, Mrgprd+ neurons respond almost exclusively to extracellular ATP with currents similar to homomeric P2X3 receptors. They show little or no sensitivity to other putative nociceptive agonists, including capsaicin, cinnamaldehyde, menthol, pH 6.0, or glutamate. These properties, together with selective innervation of the stratum granulosum, indicate that Mrgprd+ neurons are nociceptors in the outer epidermis and may respond indirectly to external stimuli by detecting ATP release in the skin.
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Affiliation(s)
- G Dussor
- Vollum Institute L474, Oregon Health and Science University, Portland, Oregon, USA.
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