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Iizumi M, Oota-Ishigaki A, Yamashita M, Hayashi T. Reduced Effect of Anticonvulsants on AMPA Receptor Palmitoylation-Deficient Mice. Front Pharmacol 2021; 12:711737. [PMID: 34483921 PMCID: PMC8416418 DOI: 10.3389/fphar.2021.711737] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2021] [Accepted: 08/05/2021] [Indexed: 12/29/2022] Open
Abstract
AMPA receptors are responsible for fast excitatory synaptic transmission in the mammalian brain. Post-translational protein S-palmitoylation of AMPA receptor subunits GluA1-4 reversibly regulates synaptic AMPA receptor expression, resulting in long-lasting changes in excitatory synaptic strengths. Our previous studies have shown that GluA1 C-terminal palmitoylation-deficient (GluA1C811S) mice exhibited hyperexcitability in the cerebrum and elevated seizure susceptibility without affecting brain structure or basal synaptic transmission. Moreover, some inhibitory GABAergic synapses-targeting anticonvulsants, such as valproic acid, phenobarbital, and diazepam, had less effect on these AMPA receptor palmitoylation-deficient mutant mice. This work explores pharmacological effect of voltage-gated ion channel-targeted anticonvulsants, phenytoin and trimethadione, on GluA1C811S mice. Similar to GABAergic synapses-targeting anticonvulsants, anticonvulsive effects were also reduced for both sodium channel- and calcium channel-blocking anticonvulsants, which suppress excess excitation. These data strongly suggest that the GluA1C811S mice generally underlie the excessive excitability in response to seizure-inducing stimulation. AMPA receptor palmitoylation site could be a novel target to develop unprecedented type of anticonvulsants and GluA1C811S mice are suitable as a model animal for broadly evaluating pharmacological effectiveness of antiepileptic drugs.
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Affiliation(s)
- Madoka Iizumi
- National Institute of Neuroscience, National Center of Neurology and Psychiatry (NCNP), Kodaira, Japan
| | - Akiko Oota-Ishigaki
- Biomedical Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Japan
| | - Mariko Yamashita
- National Institute of Neuroscience, National Center of Neurology and Psychiatry (NCNP), Kodaira, Japan
| | - Takashi Hayashi
- National Institute of Neuroscience, National Center of Neurology and Psychiatry (NCNP), Kodaira, Japan.,Biomedical Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Japan
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52
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Chatterjee D, Mahabir S, Chatterjee D, Gerlai R. Lasting effects of mild embryonic ethanol exposure on voltage-gated ion channels in adult zebrafish brain. Prog Neuropsychopharmacol Biol Psychiatry 2021; 110:110327. [PMID: 33864849 DOI: 10.1016/j.pnpbp.2021.110327] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/28/2020] [Revised: 02/28/2021] [Accepted: 04/09/2021] [Indexed: 02/06/2023]
Abstract
The zebrafish is increasingly well utilized in alcohol research, particularly in modeling human fetal alcohol spectrum disorders (FASD). FASD results from alcohol reaching the developing fetus intra utero, a completely preventable yet prevalent and devastating life-long disorder. The hope with animal models, including the zebrafish, is to discover the mechanisms underlying this disease, which may aid treatment and diagnosis. In the past, we developed an embryonic alcohol exposure regimen that is aimed at mimicking the milder, and most prevalent, forms of FASD in zebrafish. We have found numerous lasting alterations in behavior, neurochemistry, neuronal markers and glial cell phenotypes in this zebrafish FASD model. Using the same model (2 h long bath immersion of 24 h post-fertilization old zebrafish eggs into 1% vol/vol ethanol), here we conduct a proof of concept analysis of voltage-gated cation channels, investigating potential embryonic alcohol induced changes in L-, T- and N- type Ca++ and the SCN1A Na+ channels using Western blot followed by immunohistochemical analysis of the same channels in the pallium and cerebellum of the zebrafish brain. We report significant reduction of expression in all four channel proteins using both methods. We conclude that reduced voltage-gated cation channel expression induced by short and low dose exposure to alcohol during embryonic development of zebrafish may contribute to the previously demonstrated lasting behavioral and neurobiological changes.
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Affiliation(s)
| | - Samantha Mahabir
- Department of Psychology, University of Toronto, Mississauga, Ontario, Canada
| | | | - Robert Gerlai
- Department of Psychology, University of Toronto, Mississauga, Ontario, Canada.
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Zhang J, Chen X, Eaton M, Wu J, Ma Z, Lai S, Park A, Ahmad TS, Que Z, Lee JH, Xiao T, Li Y, Wang Y, Olivero-Acosta MI, Schaber JA, Jayant K, Yuan C, Huang Z, Lanman NA, Skarnes WC, Yang Y. Severe deficiency of the voltage-gated sodium channel Na V1.2 elevates neuronal excitability in adult mice. Cell Rep 2021; 36:109495. [PMID: 34348148 PMCID: PMC8382316 DOI: 10.1016/j.celrep.2021.109495] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2021] [Revised: 06/30/2021] [Accepted: 07/14/2021] [Indexed: 12/13/2022] Open
Abstract
Scn2a encodes the voltage-gated sodium channel NaV1.2, a main mediator of neuronal action potential firing. The current paradigm suggests that NaV1.2 gain-of-function variants enhance neuronal excitability, resulting in epilepsy, whereas NaV1.2 deficiency impairs neuronal excitability, contributing to autism. However, this paradigm does not explain why ∼20%-30% of individuals with NaV1.2 deficiency still develop seizures. Here, we report the counterintuitive finding that severe NaV1.2 deficiency results in increased neuronal excitability. Using a NaV1.2-deficient mouse model, we show enhanced intrinsic excitability of principal neurons in the prefrontal cortex and striatum, brain regions known to be involved in Scn2a-related seizures. This increased excitability is autonomous and reversible by genetic restoration of Scn2a expression in adult mice. RNA sequencing reveals downregulation of multiple potassium channels, including KV1.1. Correspondingly, KV channel openers alleviate the hyperexcitability of NaV1.2-deficient neurons. This unexpected neuronal hyperexcitability may serve as a cellular basis underlying NaV1.2 deficiency-related seizures.
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Affiliation(s)
- Jingliang Zhang
- Department of Medicinal Chemistry and Molecular Pharmacology, College of Pharmacy, Purdue University, West Lafayette, IN 47907, USA; Purdue Institute for Integrative Neuroscience, Purdue University, West Lafayette, IN 47907, USA
| | - Xiaoling Chen
- Department of Medicinal Chemistry and Molecular Pharmacology, College of Pharmacy, Purdue University, West Lafayette, IN 47907, USA; Purdue Institute for Integrative Neuroscience, Purdue University, West Lafayette, IN 47907, USA; Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN 47907, USA
| | - Muriel Eaton
- Department of Medicinal Chemistry and Molecular Pharmacology, College of Pharmacy, Purdue University, West Lafayette, IN 47907, USA; Purdue Institute for Integrative Neuroscience, Purdue University, West Lafayette, IN 47907, USA
| | - Jiaxiang Wu
- Department of Medicinal Chemistry and Molecular Pharmacology, College of Pharmacy, Purdue University, West Lafayette, IN 47907, USA; Purdue Institute for Integrative Neuroscience, Purdue University, West Lafayette, IN 47907, USA
| | - Zhixiong Ma
- Department of Medicinal Chemistry and Molecular Pharmacology, College of Pharmacy, Purdue University, West Lafayette, IN 47907, USA; Purdue Institute for Integrative Neuroscience, Purdue University, West Lafayette, IN 47907, USA
| | - Shirong Lai
- Department of Medicinal Chemistry and Molecular Pharmacology, College of Pharmacy, Purdue University, West Lafayette, IN 47907, USA; Purdue Institute for Integrative Neuroscience, Purdue University, West Lafayette, IN 47907, USA
| | - Anthony Park
- Department of Medicinal Chemistry and Molecular Pharmacology, College of Pharmacy, Purdue University, West Lafayette, IN 47907, USA; Purdue Institute for Integrative Neuroscience, Purdue University, West Lafayette, IN 47907, USA
| | - Talha S Ahmad
- Department of Medicinal Chemistry and Molecular Pharmacology, College of Pharmacy, Purdue University, West Lafayette, IN 47907, USA; Purdue Institute for Integrative Neuroscience, Purdue University, West Lafayette, IN 47907, USA
| | - Zhefu Que
- Department of Medicinal Chemistry and Molecular Pharmacology, College of Pharmacy, Purdue University, West Lafayette, IN 47907, USA; Purdue Institute for Integrative Neuroscience, Purdue University, West Lafayette, IN 47907, USA
| | - Ji Hea Lee
- Department of Medicinal Chemistry and Molecular Pharmacology, College of Pharmacy, Purdue University, West Lafayette, IN 47907, USA; Purdue Institute for Integrative Neuroscience, Purdue University, West Lafayette, IN 47907, USA
| | - Tiange Xiao
- Department of Medicinal Chemistry and Molecular Pharmacology, College of Pharmacy, Purdue University, West Lafayette, IN 47907, USA; Purdue Institute for Integrative Neuroscience, Purdue University, West Lafayette, IN 47907, USA
| | - Yuansong Li
- Department of Medicinal Chemistry and Molecular Pharmacology, College of Pharmacy, Purdue University, West Lafayette, IN 47907, USA; Purdue Institute for Integrative Neuroscience, Purdue University, West Lafayette, IN 47907, USA
| | - Yujia Wang
- Department of Medicinal Chemistry and Molecular Pharmacology, College of Pharmacy, Purdue University, West Lafayette, IN 47907, USA; Purdue Institute for Integrative Neuroscience, Purdue University, West Lafayette, IN 47907, USA
| | - Maria I Olivero-Acosta
- Department of Medicinal Chemistry and Molecular Pharmacology, College of Pharmacy, Purdue University, West Lafayette, IN 47907, USA; Purdue Institute for Integrative Neuroscience, Purdue University, West Lafayette, IN 47907, USA
| | - James A Schaber
- Bioscience Imaging Facility, Bindley Bioscience Center, Purdue University, West Lafayette, IN 47907, USA
| | - Krishna Jayant
- Purdue Institute for Integrative Neuroscience, Purdue University, West Lafayette, IN 47907, USA; Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN 47907, USA
| | - Chongli Yuan
- Davidson School of Chemical Engineering, Purdue University, West Lafayette, IN 47907, USA
| | - Zhuo Huang
- Department of Molecular and Cellular Pharmacology, School of Pharmaceutical Sciences, Peking University Health Science Center, Beijing 100191, China
| | - Nadia A Lanman
- Department of Comparative Pathobiology, Purdue University, West Lafayette, IN 47907, USA; Purdue Center for Cancer Research, Purdue University, West Lafayette, IN 47907, USA
| | - William C Skarnes
- The Jackson Laboratory for Genomic Medicine, Farmington, CT 06032, USA
| | - Yang Yang
- Department of Medicinal Chemistry and Molecular Pharmacology, College of Pharmacy, Purdue University, West Lafayette, IN 47907, USA; Purdue Institute for Integrative Neuroscience, Purdue University, West Lafayette, IN 47907, USA.
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Tetrodotoxin: A New Strategy to Treat Visceral Pain? Toxins (Basel) 2021; 13:toxins13070496. [PMID: 34357968 PMCID: PMC8310099 DOI: 10.3390/toxins13070496] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2021] [Revised: 07/08/2021] [Accepted: 07/13/2021] [Indexed: 12/13/2022] Open
Abstract
Visceral pain is one of the most common symptoms associated with functional gastrointestinal (GI) disorders. Although the origin of these symptoms has not been clearly defined, the implication of both the central and peripheral nervous systems in visceral hypersensitivity is well established. The role of several pathways in visceral nociception has been explored, as well as the influence of specific receptors on afferent neurons, such as voltage-gated sodium channels (VGSCs). VGSCs initiate action potentials and dysfunction of these channels has recently been associated with painful GI conditions. Current treatments for visceral pain generally involve opioid based drugs, which are associated with important side-effects and a loss of effectiveness or tolerance. Hence, efforts have been intensified to find new, more effective and longer-lasting therapies. The implication of VGSCs in visceral hypersensitivity has drawn attention to tetrodotoxin (TTX), a relatively selective sodium channel blocker, as a possible and promising molecule to treat visceral pain and related diseases. As such, here we will review the latest information regarding this toxin that is relevant to the treatment of visceral pain and the possible advantages that it may offer relative to other treatments, alone or in combination.
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55
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Ion Channels as New Attractive Targets to Improve Re-Myelination Processes in the Brain. Int J Mol Sci 2021; 22:ijms22147277. [PMID: 34298893 PMCID: PMC8305962 DOI: 10.3390/ijms22147277] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2021] [Revised: 06/28/2021] [Accepted: 07/01/2021] [Indexed: 12/20/2022] Open
Abstract
Multiple sclerosis (MS) is the most demyelinating disease of the central nervous system (CNS) characterized by neuroinflammation. Oligodendrocyte progenitor cells (OPCs) are cycling cells in the developing and adult CNS that, under demyelinating conditions, migrate to the site of lesions and differentiate into mature oligodendrocytes to remyelinate damaged axons. However, this process fails during disease chronicization due to impaired OPC differentiation. Moreover, OPCs are crucial players in neuro-glial communication as they receive synaptic inputs from neurons and express ion channels and neurotransmitter/neuromodulator receptors that control their maturation. Ion channels are recognized as attractive therapeutic targets, and indeed ligand-gated and voltage-gated channels can both be found among the top five pharmaceutical target groups of FDA-approved agents. Their modulation ameliorates some of the symptoms of MS and improves the outcome of related animal models. However, the exact mechanism of action of ion-channel targeting compounds is often still unclear due to the wide expression of these channels on neurons, glia, and infiltrating immune cells. The present review summarizes recent findings in the field to get further insights into physio-pathophysiological processes and possible therapeutic mechanisms of drug actions.
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56
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Boscia F, Elkjaer ML, Illes Z, Kukley M. Altered Expression of Ion Channels in White Matter Lesions of Progressive Multiple Sclerosis: What Do We Know About Their Function? Front Cell Neurosci 2021; 15:685703. [PMID: 34276310 PMCID: PMC8282214 DOI: 10.3389/fncel.2021.685703] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2021] [Accepted: 05/23/2021] [Indexed: 12/19/2022] Open
Abstract
Despite significant advances in our understanding of the pathophysiology of multiple sclerosis (MS), knowledge about contribution of individual ion channels to axonal impairment and remyelination failure in progressive MS remains incomplete. Ion channel families play a fundamental role in maintaining white matter (WM) integrity and in regulating WM activities in axons, interstitial neurons, glia, and vascular cells. Recently, transcriptomic studies have considerably increased insight into the gene expression changes that occur in diverse WM lesions and the gene expression fingerprint of specific WM cells associated with secondary progressive MS. Here, we review the ion channel genes encoding K+, Ca2+, Na+, and Cl- channels; ryanodine receptors; TRP channels; and others that are significantly and uniquely dysregulated in active, chronic active, inactive, remyelinating WM lesions, and normal-appearing WM of secondary progressive MS brain, based on recently published bulk and single-nuclei RNA-sequencing datasets. We discuss the current state of knowledge about the corresponding ion channels and their implication in the MS brain or in experimental models of MS. This comprehensive review suggests that the intense upregulation of voltage-gated Na+ channel genes in WM lesions with ongoing tissue damage may reflect the imbalance of Na+ homeostasis that is observed in progressive MS brain, while the upregulation of a large number of voltage-gated K+ channel genes may be linked to a protective response to limit neuronal excitability. In addition, the altered chloride homeostasis, revealed by the significant downregulation of voltage-gated Cl- channels in MS lesions, may contribute to an altered inhibitory neurotransmission and increased excitability.
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Affiliation(s)
- Francesca Boscia
- Division of Pharmacology, Department of Neuroscience, Reproductive and Dentistry Sciences, School of Medicine, University of Naples "Federico II", Naples, Italy
| | - Maria Louise Elkjaer
- Neurology Research Unit, Department of Clinical Research, University of Southern Denmark, Odense, Denmark.,Department of Neurobiology Research, Institute of Molecular Medicine, University of Southern Denmark, Odense, Denmark
| | - Zsolt Illes
- Neurology Research Unit, Department of Clinical Research, University of Southern Denmark, Odense, Denmark.,Department of Neurobiology Research, Institute of Molecular Medicine, University of Southern Denmark, Odense, Denmark.,Department of Neurology, Odense University Hospital, Odense, Denmark
| | - Maria Kukley
- Achucarro Basque Center for Neuroscience, Leioa, Spain.,Ikerbasque Basque Foundation for Science, Bilbao, Spain
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57
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Lin W, Zhang WW, Lyu N, Cao H, Xu WD, Zhang YQ. Growth Differentiation Factor-15 Produces Analgesia by Inhibiting Tetrodotoxin-Resistant Nav1.8 Sodium Channel Activity in Rat Primary Sensory Neurons. Neurosci Bull 2021; 37:1289-1302. [PMID: 34076854 PMCID: PMC8423960 DOI: 10.1007/s12264-021-00709-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2020] [Accepted: 02/10/2021] [Indexed: 01/01/2023] Open
Abstract
Growth differentiation factor 15 (GDF-15) is a member of the transforming growth factor-β superfamily. It is widely distributed in the central and peripheral nervous systems. Whether and how GDF-15 modulates nociceptive signaling remains unclear. Behaviorally, we found that peripheral GDF-15 significantly elevated nociceptive response thresholds to mechanical and thermal stimuli in naïve and arthritic rats. Electrophysiologically, we demonstrated that GDF-15 decreased the excitability of small-diameter dorsal root ganglia (DRG) neurons. Furthermore, GDF-15 concentration-dependently suppressed tetrodotoxin-resistant sodium channel Nav1.8 currents, and shifted the steady-state inactivation curves of Nav1.8 in a hyperpolarizing direction. GDF-15 also reduced window currents and slowed down the recovery rate of Nav1.8 channels, suggesting that GDF-15 accelerated inactivation and slowed recovery of the channel. Immunohistochemistry results showed that activin receptor-like kinase-2 (ALK2) was widely expressed in DRG medium- and small-diameter neurons, and some of them were Nav1.8-positive. Blockade of ALK2 prevented the GDF-15-induced inhibition of Nav1.8 currents and nociceptive behaviors. Inhibition of PKA and ERK, but not PKC, blocked the inhibitory effect of GDF-15 on Nav1.8 currents. These results suggest a functional link between GDF-15 and Nav1.8 in DRG neurons via ALK2 receptors and PKA associated with MEK/ERK, which mediate the peripheral analgesia of GDF-15.
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Affiliation(s)
- Wei Lin
- Department of Translational Neuroscience, Jing'an District Centre Hospital of Shanghai, State Key Laboratory of Medical Neurobiology and Institutes of Brain Science, Fudan University, Shanghai, 200032, China
| | - Wen-Wen Zhang
- Department of Translational Neuroscience, Jing'an District Centre Hospital of Shanghai, State Key Laboratory of Medical Neurobiology and Institutes of Brain Science, Fudan University, Shanghai, 200032, China
| | - Ning Lyu
- Department of Translational Neuroscience, Jing'an District Centre Hospital of Shanghai, State Key Laboratory of Medical Neurobiology and Institutes of Brain Science, Fudan University, Shanghai, 200032, China.
| | - Hong Cao
- Department of Translational Neuroscience, Jing'an District Centre Hospital of Shanghai, State Key Laboratory of Medical Neurobiology and Institutes of Brain Science, Fudan University, Shanghai, 200032, China
| | - Wen-Dong Xu
- Department of Translational Neuroscience, Jing'an District Centre Hospital of Shanghai, State Key Laboratory of Medical Neurobiology and Institutes of Brain Science, Fudan University, Shanghai, 200032, China. .,Department of Hand Surgery, Huashan Hospital, Fudan University, Shanghai, 200040, China.
| | - Yu-Qiu Zhang
- Department of Translational Neuroscience, Jing'an District Centre Hospital of Shanghai, State Key Laboratory of Medical Neurobiology and Institutes of Brain Science, Fudan University, Shanghai, 200032, China. .,Department of Neurobiology, School of Basic Medical Sciences, Shanghai Medical College, Fudan University, Shanghai, 200032, China.
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58
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Lee SW, Han HC. Methylene Blue Application to Lessen Pain: Its Analgesic Effect and Mechanism. Front Neurosci 2021; 15:663650. [PMID: 34079436 PMCID: PMC8165385 DOI: 10.3389/fnins.2021.663650] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2021] [Accepted: 04/16/2021] [Indexed: 12/12/2022] Open
Abstract
Methylene blue (MB) is a cationic thiazine dye, widely used as a biological stain and chemical indicator. Growing evidence have revealed that MB functions to restore abnormal vasodilation and notably it is implicated even in pain relief. Physicians began to inject MB into degenerated disks to relieve pain in patients with chronic discogenic low back pain (CDLBP), and some of them achieved remarkable outcomes. For osteoarthritis and colitis, MB abates inflammation by suppressing nitric oxide production, and ultimately relieves pain. However, despite this clinical efficacy, MB has not attracted much public attention in terms of pain relief. Accordingly, this review focuses on how MB lessens pain, noting three major actions of this dye: anti-inflammation, sodium current reduction, and denervation. Moreover, we showed controversies over the efficacy of MB on CDLBP and raised also toxicity issues to look into the limitation of MB application. This analysis is the first attempt to illustrate its analgesic effects, which may offer a novel insight into MB as a pain-relief dye.
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Affiliation(s)
- Seung Won Lee
- Good Doctor Research Institute, College of Medicine, Korea University, Seoul, South Korea
| | - Hee Chul Han
- Department of Physiology, College of Medicine and Neuroscience Research Institute, Korea University, Seoul, South Korea
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Toxin Ct1a, from venom of Centruroides tecomanus, modifies the spontaneous firing frequency of neurons in the suprachiasmatic nucleus. Toxicon 2021; 197:114-125. [PMID: 33901550 DOI: 10.1016/j.toxicon.2021.04.015] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2020] [Revised: 03/26/2021] [Accepted: 04/19/2021] [Indexed: 11/21/2022]
Abstract
The peptide, denominated Ct1a, is a β-toxin of 66 amino acids, isolated from venom of the scorpion, Centruroides tecomanus, collected in Colima, Mexico. This toxin was purified using size exclusion, cationic exchange, and reverse phase chromatography. It is the most abundant toxin, representing 1.7% of the soluble venom. Its molecular mass of 7588.9 Da was determined by mass spectrometry. The amino acid sequence was determined by Edman degradation and confirmed by transcriptomic analysis. Since neurons of the suprachiasmatic nucleus (SCN) maintain a spontaneous firing rate (SFR), we evaluated the physiological effects of toxin Ct1a on these neurons. The SFR exhibited a bimodal concentration-dependent response: 100 nM of Ct1a increased the SFR by 223%, whereas 500 nM and 1000 nM reduced it to 42% and 7%, respectively. Control experiments, consisting of recordings of the SFR during a time similar to that used in Ct1a testing, showed stability throughout the trials. Experiments carried out with denatured Ct1a toxin (500 nM) caused no variation in SFR recordings. Action potentials of SCN neurons, before and after Ct1a (100 nM) showed changes in the time constants of depolarization and repolarization phases, amplitude, and half-time. Finally, recordings of hNav1.6 sodium currents indicated that Ct1a shifts the channel activation to a more negative potential and reduces the amplitude of the peak current. These results all demonstrate that toxin Ct1a affects the SFR of SCN neurons by acting upon sodium channels of sub-type 1.6, implicating them in regulation of the SFR of SCN neurons.
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Aldohbeyb AA, Vigh J, Lear KL. New methods for quantifying rapidity of action potential onset differentiate neuron types. PLoS One 2021; 16:e0247242. [PMID: 33831000 PMCID: PMC8032118 DOI: 10.1371/journal.pone.0247242] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2020] [Accepted: 02/03/2021] [Indexed: 11/23/2022] Open
Abstract
Two new methods for quantifying the rapidity of action potential onset have lower relative standard deviations and better distinguish neuron cell types than current methods. Action potentials (APs) in most central mammalian neurons exhibit sharp onset dynamics. The main views explaining such an abrupt onset differ. Some studies suggest sharp onsets reflect cooperative sodium channels activation, while others suggest they reflect AP backpropagation from the axon initial segment. However, AP onset rapidity is defined subjectively in these studies, often using the slope at an arbitrary value on the phase plot. Thus, we proposed more systematic methods using the membrane potential's second-time derivative ([Formula: see text]) peak width. Here, the AP rapidity was measured for four different cortical and hippocampal neuron types using four quantification methods: the inverse of full-width at the half maximum of the [Formula: see text] peak (IFWd2), the inverse of half-width at the half maximum of the [Formula: see text] peak (IHWd2), the phase plot slope, and the error ratio method. The IFWd2 and IHWd2 methods show the smallest variation among neurons of the same type. Furthermore, the AP rapidity, using the [Formula: see text] peak width methods, significantly differentiates between different types of neurons, indicating that AP rapidity can be used to classify neuron types. The AP rapidity measured using the IFWd2 method was able to differentiate between all four neuron types analyzed. Therefore, the [Formula: see text] peak width methods provide another sensitive tool to investigate the mechanisms impacting the AP onset dynamics.
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Affiliation(s)
- Ahmed A. Aldohbeyb
- School of Biomedical Engineering, Colorado State University, Fort Collins, CO, United States of America
- Department of Biomedical Technology, King Saud University, Riyadh, Kingdom of Saudi Arabia
| | - Jozsef Vigh
- School of Biomedical Engineering, Colorado State University, Fort Collins, CO, United States of America
- Department of Biomedical Sciences, Colorado State University, Fort Collins, CO, United States of America
| | - Kevin L. Lear
- School of Biomedical Engineering, Colorado State University, Fort Collins, CO, United States of America
- Department of Electrical and Computer Engineering, Colorado State University, Fort Collins, CO, United States of America
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61
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Eaton M, Zhang J, Ma Z, Park AC, Lietzke E, Romero CM, Liu Y, Coleman ER, Chen X, Xiao T, Que Z, Lai S, Wu J, Lee JH, Palant S, Nguyen HP, Huang Z, Skarnes WC, Koss WA, Yang Y. Generation and basic characterization of a gene-trap knockout mouse model of Scn2a with a substantial reduction of voltage-gated sodium channel Na v 1.2 expression. GENES, BRAIN, AND BEHAVIOR 2021; 20:e12725. [PMID: 33369088 DOI: 10.1111/gbb.12725] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/10/2020] [Revised: 12/22/2020] [Accepted: 12/22/2020] [Indexed: 12/17/2022]
Abstract
Large-scale genetic studies revealed SCN2A as one of the most frequently mutated genes in patients with neurodevelopmental disorders. SCN2A encodes for the voltage-gated sodium channel isoform 1.2 (Nav 1.2) expressed in the neurons of the central nervous system. Homozygous knockout (null) of Scn2a in mice is perinatal lethal, whereas heterozygous knockout of Scn2a (Scn2a+/- ) results in mild behavior abnormalities. The Nav 1.2 expression level in Scn2a+/- mice is reported to be around 50-60% of the wild-type (WT) level, which indicates that a close to 50% reduction of Nav 1.2 expression may not be sufficient to lead to major behavioral phenotypes in mice. To overcome this barrier, we characterized a novel mouse model of severe Scn2a deficiency using a targeted gene-trap knockout (gtKO) strategy. This approach produces viable homozygous mice (Scn2agtKO/gtKO ) that can survive to adulthood, with about a quarter of Nav 1.2 expression compared to WT mice. Innate behaviors like nesting and mating were profoundly disrupted in Scn2agtKO/gtKO mice. Notably, Scn2agtKO/gtKO mice have a significantly decreased center duration compared to WT in the open field test, suggesting anxiety-like behaviors in a novel, open space. These mice also have decreased thermal and cold tolerance. Additionally, Scn2agtKO/gtKO mice have increased fix-pattern exploration in the novel object exploration test and a slight increase in grooming, indicating a detectable level of repetitive behaviors. They bury little to no marbles and have decreased interaction with novel objects. These Scn2a gene-trap knockout mice thus provide a unique model to study pathophysiology associated with severe Scn2a deficiency.
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Affiliation(s)
- Muriel Eaton
- Department of Medicinal Chemistry and Molecular Pharmacology, College of Pharmacy, Purdue University, West Lafayette, Indiana, USA
- Purdue Institute for Integrative Neuroscience, Purdue University, West Lafayette, Indiana, USA
| | - Jingliang Zhang
- Department of Medicinal Chemistry and Molecular Pharmacology, College of Pharmacy, Purdue University, West Lafayette, Indiana, USA
- Purdue Institute for Integrative Neuroscience, Purdue University, West Lafayette, Indiana, USA
| | - Zhixiong Ma
- Department of Medicinal Chemistry and Molecular Pharmacology, College of Pharmacy, Purdue University, West Lafayette, Indiana, USA
- Purdue Institute for Integrative Neuroscience, Purdue University, West Lafayette, Indiana, USA
| | - Anthony C Park
- Department of Medicinal Chemistry and Molecular Pharmacology, College of Pharmacy, Purdue University, West Lafayette, Indiana, USA
- Purdue Institute for Integrative Neuroscience, Purdue University, West Lafayette, Indiana, USA
| | - Emma Lietzke
- Department of Medicinal Chemistry and Molecular Pharmacology, College of Pharmacy, Purdue University, West Lafayette, Indiana, USA
- Purdue Institute for Integrative Neuroscience, Purdue University, West Lafayette, Indiana, USA
| | - Chloé M Romero
- Department of Medicinal Chemistry and Molecular Pharmacology, College of Pharmacy, Purdue University, West Lafayette, Indiana, USA
- Purdue Institute for Integrative Neuroscience, Purdue University, West Lafayette, Indiana, USA
| | - Yushuang Liu
- Department of Medicinal Chemistry and Molecular Pharmacology, College of Pharmacy, Purdue University, West Lafayette, Indiana, USA
- Purdue Institute for Integrative Neuroscience, Purdue University, West Lafayette, Indiana, USA
| | - Emily R Coleman
- Department of Medicinal Chemistry and Molecular Pharmacology, College of Pharmacy, Purdue University, West Lafayette, Indiana, USA
- Purdue Institute for Integrative Neuroscience, Purdue University, West Lafayette, Indiana, USA
| | - Xiaoling Chen
- Department of Medicinal Chemistry and Molecular Pharmacology, College of Pharmacy, Purdue University, West Lafayette, Indiana, USA
- Purdue Institute for Integrative Neuroscience, Purdue University, West Lafayette, Indiana, USA
| | - Tiange Xiao
- Department of Medicinal Chemistry and Molecular Pharmacology, College of Pharmacy, Purdue University, West Lafayette, Indiana, USA
- Purdue Institute for Integrative Neuroscience, Purdue University, West Lafayette, Indiana, USA
| | - Zhefu Que
- Department of Medicinal Chemistry and Molecular Pharmacology, College of Pharmacy, Purdue University, West Lafayette, Indiana, USA
- Purdue Institute for Integrative Neuroscience, Purdue University, West Lafayette, Indiana, USA
| | - Shirong Lai
- Department of Medicinal Chemistry and Molecular Pharmacology, College of Pharmacy, Purdue University, West Lafayette, Indiana, USA
- Purdue Institute for Integrative Neuroscience, Purdue University, West Lafayette, Indiana, USA
| | - Jiaxiang Wu
- Department of Medicinal Chemistry and Molecular Pharmacology, College of Pharmacy, Purdue University, West Lafayette, Indiana, USA
- Purdue Institute for Integrative Neuroscience, Purdue University, West Lafayette, Indiana, USA
| | - Ji Hea Lee
- Department of Medicinal Chemistry and Molecular Pharmacology, College of Pharmacy, Purdue University, West Lafayette, Indiana, USA
- Purdue Institute for Integrative Neuroscience, Purdue University, West Lafayette, Indiana, USA
| | - Sophia Palant
- Department of Medicinal Chemistry and Molecular Pharmacology, College of Pharmacy, Purdue University, West Lafayette, Indiana, USA
- Purdue Institute for Integrative Neuroscience, Purdue University, West Lafayette, Indiana, USA
| | - Huynhvi P Nguyen
- Department of Medicinal Chemistry and Molecular Pharmacology, College of Pharmacy, Purdue University, West Lafayette, Indiana, USA
- Purdue Institute for Integrative Neuroscience, Purdue University, West Lafayette, Indiana, USA
| | - Zhuo Huang
- Department of Molecular and Cellular Pharmacology, School of Pharmaceutical Sciences, Peking University Health Science Center, Beijing, China
| | - William C Skarnes
- Department of Cellular Engineering, The Jackson Laboratory for Genomic Medicine, Farmington, Connecticut, USA
| | - Wendy A Koss
- Purdue Institute for Integrative Neuroscience, Purdue University, West Lafayette, Indiana, USA
- Office of the Executive Vice President for Research and Partnerships, Purdue University, West Lafayette, Indiana, USA
| | - Yang Yang
- Department of Medicinal Chemistry and Molecular Pharmacology, College of Pharmacy, Purdue University, West Lafayette, Indiana, USA
- Purdue Institute for Integrative Neuroscience, Purdue University, West Lafayette, Indiana, USA
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Oshiro N, Nagasawa H, Kuniyoshi K, Kobayashi N, Sugita-Konishi Y, Asakura H, Yasumoto T. Characteristic Distribution of Ciguatoxins in the Edible Parts of a Grouper, Variola louti. Toxins (Basel) 2021; 13:218. [PMID: 33803043 PMCID: PMC8002984 DOI: 10.3390/toxins13030218] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2020] [Revised: 03/14/2021] [Accepted: 03/15/2021] [Indexed: 12/21/2022] Open
Abstract
Ciguatera fish poisoning (CFP) is one of the most frequently encountered seafood poisoning syndromes; it is caused by the consumption of marine finfish contaminated with ciguatoxins (CTXs). The majority of CFP cases result from eating fish flesh, but a traditional belief exists among people that the head and viscera are more toxic and should be avoided. Unlike the viscera, scientific data to support the legendary high toxicity of the head is scarce. We prepared tissue samples from the fillet, head, and eyes taken from five yellow-edged lyretail (Variola louti) individuals sourced from Okinawa, Japan, and analyzed the CTXs by LC-MS/MS. Three CTXs, namely, CTX1B, 52-epi-54-deoxyCTX1B, and 54-deoxyCTX1B, were confirmed in similar proportions. The toxins were distributed nearly evenly in the flesh, prepared separately from the fillet and head. Within the same individual specimen, the flesh in the fillet and the flesh from the head, tested separately, had the same level and composition of toxins. We, therefore, conclude that flesh samples for LC-MS/MS analysis can be taken from any part of the body. However, the tissue surrounding the eyeball displayed CTX levels two to four times higher than those of the flesh. The present study is the first to provide scientific data demonstrating the high toxicity of the eyes.
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Affiliation(s)
- Naomasa Oshiro
- National Institute of Health Sciences, 3-25-26 Tonomachi, Kawasaki, Kanagawa 210-9501, Japan; (H.N.); (K.K.); (H.A.)
| | - Hiroya Nagasawa
- National Institute of Health Sciences, 3-25-26 Tonomachi, Kawasaki, Kanagawa 210-9501, Japan; (H.N.); (K.K.); (H.A.)
- Department of Food and Life Science, School of Life and Environmental Science, Azabu University, 1-17-71 Fuchinobe, Chuo-ku, Sagamihara, Kanagawa 252-5201, Japan; (N.K.); (Y.S.-K.)
| | - Kyoko Kuniyoshi
- National Institute of Health Sciences, 3-25-26 Tonomachi, Kawasaki, Kanagawa 210-9501, Japan; (H.N.); (K.K.); (H.A.)
| | - Naoki Kobayashi
- Department of Food and Life Science, School of Life and Environmental Science, Azabu University, 1-17-71 Fuchinobe, Chuo-ku, Sagamihara, Kanagawa 252-5201, Japan; (N.K.); (Y.S.-K.)
| | - Yoshiko Sugita-Konishi
- Department of Food and Life Science, School of Life and Environmental Science, Azabu University, 1-17-71 Fuchinobe, Chuo-ku, Sagamihara, Kanagawa 252-5201, Japan; (N.K.); (Y.S.-K.)
| | - Hiroshi Asakura
- National Institute of Health Sciences, 3-25-26 Tonomachi, Kawasaki, Kanagawa 210-9501, Japan; (H.N.); (K.K.); (H.A.)
| | - Takeshi Yasumoto
- Tama Laboratory, Japan Food Research Laboratories, 6-11-10 Nagayama, Tama, Tokyo 206-0025, Japan;
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63
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Kerth CM, Hautvast P, Körner J, Lampert A, Meents JE. Phosphorylation of a chronic pain mutation in the voltage-gated sodium channel Nav1.7 increases voltage sensitivity. J Biol Chem 2021; 296:100227. [PMID: 33361158 PMCID: PMC7948457 DOI: 10.1074/jbc.ra120.014288] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2020] [Revised: 12/17/2020] [Accepted: 12/22/2020] [Indexed: 12/19/2022] Open
Abstract
Mutations in voltage-gated sodium channels (Navs) can cause alterations in pain sensation, such as chronic pain diseases like inherited erythromelalgia. The mutation causing inherited erythromelalgia, Nav1.7 p.I848T, is known to induce a hyperpolarized shift in the voltage dependence of activation in Nav1.7. So far, however, the mechanism to explain this increase in voltage sensitivity remains unknown. In the present study, we show that phosphorylation of the newly introduced Thr residue explains the functional change. We expressed wildtype human Nav1.7, the I848T mutant, or other mutations in HEK293T cells and performed whole-cell patch-clamp electrophysiology. As the insertion of a Thr residue potentially creates a novel phosphorylation site for Ser/Thr kinases and because Nav1.7 had been shown in Xenopus oocytes to be affected by protein kinases C and A, we used different nonselective and selective kinase inhibitors and activators to test the effect of phosphorylation on Nav1.7 in a human system. We identify protein kinase C, but not protein kinase A, to be responsible for the phosphorylation of T848 and thereby for the shift in voltage sensitivity. Introducing a negatively charged amino acid instead of the putative phosphorylation site mimics the effect on voltage gating to a lesser extent. 3D modeling using the published cryo-EM structure of human Nav1.7 showed that introduction of this negatively charged site seems to alter the interaction of this residue with the surrounding amino acids and thus to influence channel function. These results could provide new opportunities for the development of novel treatment options for patients with chronic pain.
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Affiliation(s)
- Clara M Kerth
- Institute of Physiology, Uniklinik RWTH Aachen University, Aachen, Germany
| | - Petra Hautvast
- Institute of Physiology, Uniklinik RWTH Aachen University, Aachen, Germany
| | - Jannis Körner
- Institute of Physiology, Uniklinik RWTH Aachen University, Aachen, Germany; Department of Anesthesiology, Uniklinik RWTH Aachen University, Aachen, Germany
| | - Angelika Lampert
- Institute of Physiology, Uniklinik RWTH Aachen University, Aachen, Germany
| | - Jannis E Meents
- Institute of Physiology, Uniklinik RWTH Aachen University, Aachen, Germany.
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64
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Bączyk M, Drzymała-Celichowska H, Mrówczyński W, Krutki P. Polarity-dependent adaptations of motoneuron electrophysiological properties after 5-wk transcutaneous spinal direct current stimulation in rats. J Appl Physiol (1985) 2020; 129:646-655. [DOI: 10.1152/japplphysiol.00301.2020] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Transcutaneous spinal direct current stimulation applied systematically for 5 wk evoked polarity-dependent adaptations in the electrophysiological properties of rat spinal motoneurons. After anodal polarization sessions, motoneurons became more excitable and could evoke higher maximum discharge frequencies during repetitive firing than motoneurons in the sham polarization group. However, no significant adaptive changes of motoneuron properties were observed after repeated cathodal polarization in comparison with the sham control group.
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Affiliation(s)
- Marcin Bączyk
- Department of Neurobiology, Poznań University of Physical Education, Poznań, Poland
| | - Hanna Drzymała-Celichowska
- Department of Neurobiology, Poznań University of Physical Education, Poznań, Poland
- Department of Biochemistry, Poznań University of Physical Education, Poznań, Poland
| | | | - Piotr Krutki
- Department of Neurobiology, Poznań University of Physical Education, Poznań, Poland
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65
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Collaço RDC, Hyslop S, Rocha T, Dorce VAC, Rowan EG, Antunes E. Neurotoxicity of Tityus bahiensis (brown scorpion) venom in sympathetic vas deferens preparations and neuronal cells. Arch Toxicol 2020; 94:3315-3327. [PMID: 32548756 PMCID: PMC7415753 DOI: 10.1007/s00204-020-02799-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2020] [Accepted: 05/28/2020] [Indexed: 01/04/2023]
Abstract
Systemic scorpion envenomation is characterized by massive neurotransmitter release from peripheral nerves mediated primarily by scorpion venoms neurotoxins. Tityus bahiensis is one of the medically most important species in Brazil, but its venom pharmacology, especially regarding to peripheral nervous system, is poorly understood. Here, we evaluated the T. bahiensis venom activity on autonomic (sympathetic) neurotransmission by using a variety of approaches, including vas deferens twitch-tension recordings, electrophysiological measurements (resting membrane potentials, spontaneous excitatory junctional potentials and whole-cell patch-clamp), calcium imaging and histomorphological analysis. Low concentrations of venom (≤ 3 μg/mL) facilitated the electrically stimulated vas deferens contractions without affecting postsynaptic receptors or damaging the smooth muscle cells. Transient TTX-sensitive sustained contractions and resting membrane depolarization were mediated mainly by massive spontaneous ATP release. High venom concentrations (≥ 10 μg/mL) blocked the muscle contractions and induced membrane depolarization. In neuronal cells (ND7-23wt), the venom increased the peak sodium current, modified the current-voltage relationship by left-shifting the Nav-channel activation curve, thereby facilitating the opening of these channels. The venom also caused a time-dependent increase in neuronal calcium influx. These results indicate that the sympathetic hyperstimulation observed in systemic envenomation is presynaptically driven, probably through the interaction of α- and β-toxins with neuronal sodium channels.
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Affiliation(s)
- Rita de Cássia Collaço
- Department of Pharmacology, Faculty of Medical Sciences, State University of Campinas (UNICAMP), Campinas, SP, Brazil.
- Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, Glasgow, UK.
| | - Stephen Hyslop
- Department of Pharmacology, Faculty of Medical Sciences, State University of Campinas (UNICAMP), Campinas, SP, Brazil
| | - Thalita Rocha
- São Francisco University (USF), Bragança Paulista, SP, Brazil
| | - Valquiria A C Dorce
- Laboratory of Pharmacology, Division for Scientific Development, Butantan Institute, São Paulo, SP, Brazil
| | - Edward G Rowan
- Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, Glasgow, UK
| | - Edson Antunes
- Department of Pharmacology, Faculty of Medical Sciences, State University of Campinas (UNICAMP), Campinas, SP, Brazil
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66
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Accumulation of Lithium in the Hippocampus of Patients With Bipolar Disorder: A Lithium-7 Magnetic Resonance Imaging Study at 7 Tesla. Biol Psychiatry 2020; 88:426-433. [PMID: 32340717 DOI: 10.1016/j.biopsych.2020.02.1181] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/19/2019] [Revised: 01/14/2020] [Accepted: 02/03/2020] [Indexed: 01/02/2023]
Abstract
BACKGROUND Lithium (Li) is a first-line treatment for bipolar disorder (BD). To study its cerebral distribution and association with plasma concentrations, we used 7Li magnetic resonance imaging at 7T in euthymic patients with BD treated with Li carbonate for at least 2 years. METHODS Three-dimensional 7Li magnetic resonance imaging scans (N = 21) were acquired with an ultra-short echo-time sequence using a non-Cartesian k-space sampling scheme. Lithium concentrations ([Li]) were estimated using a phantom replacement approach accounting for differential T1 and T2 relaxation effects. In addition to the determination of mean regional [Li] from 7 broad anatomical areas, voxel- and parcellation-based group analyses were conducted for the first time for 7Li magnetic resonance imaging. RESULTS Using unprecedented spatial sensitivity and specificity, we were able to confirm the heterogeneity of the brain Li distribution and its interindividual variability, as well as the strong correlation between plasma and average brain [Li] ([Li]B ≈ 0.40 × [Li]P, R = .74). Remarkably, our statistical analysis led to the identification of a well-defined and significant cluster corresponding closely to the left hippocampus for which high Li content was displayed consistently across our cohort. CONCLUSIONS This observation could be of interest considering 1) the major role of the hippocampus in emotion processing and regulation, 2) the consistent atrophy of the hippocampus in untreated patients with BD, and 3) the normalization effect of Li on gray matter volumes. This study paves the way for the elucidation of the relationship between Li cerebral distribution and its therapeutic response, notably in newly diagnosed patients with BD.
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67
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Encinas AC, Watkins JC, Longoria IA, Johnson JP, Hammer MF. Variable patterns of mutation density among NaV1.1, NaV1.2 and NaV1.6 point to channel-specific functional differences associated with childhood epilepsy. PLoS One 2020; 15:e0238121. [PMID: 32845893 PMCID: PMC7449494 DOI: 10.1371/journal.pone.0238121] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2020] [Accepted: 08/10/2020] [Indexed: 11/28/2022] Open
Abstract
Variants implicated in childhood epilepsy have been identified in all four voltage-gated sodium channels that initiate action potentials in the central nervous system. Previous research has focused on the functional effects of particular variants within the most studied of these channels (NaV1.1, NaV1.2 and NaV1.6); however, there have been few comparative studies across channels to infer the impact of mutations in patients with epilepsy. Here we compare patterns of variation in patient and public databases to test the hypothesis that regions of known functional significance within voltage-gated sodium (NaV) channels have an increased burden of deleterious variants. We assessed mutational burden in different regions of the Nav channels by (1) performing Fisher exact tests on odds ratios to infer excess variants in domains, segments, and loops of each channel in patient databases versus public “control” databases, and (2) comparing the cumulative distribution of variant sites along DNA sequences of each gene in patient and public databases (i.e., independent of protein structure). Patient variant density was concordant among channels in regions known to play a role in channel function, with statistically significant higher patient variant density in S4-S6 and DIII-DIV and an excess of public variants in SI-S3, DI-DII, DII-DIII. On the other hand, channel-specific patterns of patient burden were found in the NaV1.6 inactivation gate and NaV1.1 S5-S6 linkers, while NaV1.2 and NaV1.6 S4-S5 linkers and S5 segments shared patient variant patterns that contrasted with those in NaV1.1. These different patterns may reflect different roles played by the NaV1.6 inactivation gate in action potential propagation, and by NaV1.1 S5-S6 linkers in loss of function and haploinsufficiency. Interestingly, NaV1.2 and NaV1.6 both lack amino acid substitutions over significantly long stretches in both the patient and public databases suggesting that new mutations in these regions may cause embryonic lethality or a non-epileptic disease phenotype.
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Affiliation(s)
- Alejandra C. Encinas
- Graduate Program in Genetics, University of Arizona, Tucson, Arizona, United States of America
| | - Joseph C. Watkins
- Department of Mathematics, University of Arizona, Tucson, Arizona, United States of America
| | - Iris Arenas Longoria
- Department of Mathematics, University of Arizona, Tucson, Arizona, United States of America
| | | | - Michael F. Hammer
- Department of Neurology, University of Arizona, Tucson, Arizona, United States of America
- * E-mail:
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68
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Nakajima T, Kaneko Y, Dharmawan T, Kurabayashi M. Role of the voltage sensor module in Na v domain IV on fast inactivation in sodium channelopathies: The implication of closed-state inactivation. Channels (Austin) 2020; 13:331-343. [PMID: 31357904 PMCID: PMC6713248 DOI: 10.1080/19336950.2019.1649521] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
The segment 4 (S4) voltage sensor in voltage-gated sodium channels (Navs) have domain-specific functions, and the S4 segment in domain DIV (DIVS4) plays a key role in the activation and fast inactivation processes through the coupling of arginine residues in DIVS4 with residues of putative gating charge transfer center (pGCTC) in DIVS1-3. In addition, the first four arginine residues (R1-R4) in Nav DIVS4 have position-specific functions in the fast inactivation process, and mutations in these residues are associated with diverse phenotypes of Nav-related diseases (sodium channelopathies). R1 and R2 mutations commonly display a delayed fast inactivation, causing a gain-of-function, whereas R3 and R4 mutations commonly display a delayed recovery from inactivation and profound use-dependent current attenuation, causing a severe loss-of-function. In contrast, mutations of residues of pGCTC in Nav DIVS1-3 can also alter fast inactivation. Such alterations in fast inactivation may be caused by disrupted interactions of DIVS4 with DIVS1-3. Despite fast inactivation of Navs occurs from both the open-state (open-state inactivation; OSI) and closed state (closed-state inactivation; CSI), changes in CSI have received considerably less attention than those in OSI in the pathophysiology of sodium channelopathies. CSI can be altered by mutations of arginine residues in DIVS4 and residues of pGCTC in Navs, and altered CSI can be an underlying primary biophysical defect of sodium channelopathies. Therefore, CSI should receive focus in order to clarify the pathophysiology of sodium channelopathies.
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Affiliation(s)
- Tadashi Nakajima
- a Department of Cardiovascular Medicine, Gunma University Graduate School of Medicine , Maebashi , Gunma , Japan
| | - Yoshiaki Kaneko
- a Department of Cardiovascular Medicine, Gunma University Graduate School of Medicine , Maebashi , Gunma , Japan
| | - Tommy Dharmawan
- a Department of Cardiovascular Medicine, Gunma University Graduate School of Medicine , Maebashi , Gunma , Japan
| | - Masahiko Kurabayashi
- a Department of Cardiovascular Medicine, Gunma University Graduate School of Medicine , Maebashi , Gunma , Japan
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69
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Zybura AS, Baucum AJ, Rush AM, Cummins TR, Hudmon A. CaMKII enhances voltage-gated sodium channel Nav1.6 activity and neuronal excitability. J Biol Chem 2020; 295:11845-11865. [PMID: 32611770 DOI: 10.1074/jbc.ra120.014062] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2020] [Revised: 06/30/2020] [Indexed: 11/06/2022] Open
Abstract
Nav1.6 is the primary voltage-gated sodium channel isoform expressed in mature axon initial segments and nodes, making it critical for initiation and propagation of neuronal impulses. Thus, Nav1.6 modulation and dysfunction may have profound effects on input-output properties of neurons in normal and pathological conditions. Phosphorylation is a powerful and reversible mechanism regulating ion channel function. Because Nav1.6 and the multifunctional Ca2+/CaM-dependent protein kinase II (CaMKII) are independently linked to excitability disorders, we sought to investigate modulation of Nav1.6 function by CaMKII signaling. We show that inhibition of CaMKII, a Ser/Thr protein kinase associated with excitability, synaptic plasticity, and excitability disorders, with the CaMKII-specific peptide inhibitor CN21 reduces transient and persistent currents in Nav1.6-expressing Purkinje neurons by 87%. Using whole-cell voltage clamp of Nav1.6, we show that CaMKII inhibition in ND7/23 and HEK293 cells significantly reduces transient and persistent currents by 72% and produces a 5.8-mV depolarizing shift in the voltage dependence of activation. Immobilized peptide arrays and nanoflow LC-electrospray ionization/MS of Nav1.6 reveal potential sites of CaMKII phosphorylation, specifically Ser-561 and Ser-641/Thr-642 within the first intracellular loop of the channel. Using site-directed mutagenesis to test multiple potential sites of phosphorylation, we show that Ala substitutions of Ser-561 and Ser-641/Thr-642 recapitulate the depolarizing shift in activation and reduction in current density. Computational simulations to model effects of CaMKII inhibition on Nav1.6 function demonstrate dramatic reductions in spontaneous and evoked action potentials in a Purkinje cell model, suggesting that CaMKII modulation of Nav1.6 may be a powerful mechanism to regulate neuronal excitability.
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Affiliation(s)
- Agnes S Zybura
- Program in Medical Neuroscience, Paul and Carole Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis, Indiana, USA
| | - Anthony J Baucum
- Program in Medical Neuroscience, Paul and Carole Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis, Indiana, USA.,Biology Department, Indiana University-Purdue University Indianapolis, School of Science, Indianapolis, Indiana, USA
| | | | - Theodore R Cummins
- Program in Medical Neuroscience, Paul and Carole Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis, Indiana, USA.,Biology Department, Indiana University-Purdue University Indianapolis, School of Science, Indianapolis, Indiana, USA
| | - Andy Hudmon
- Program in Medical Neuroscience, Paul and Carole Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis, Indiana, USA .,Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, West Lafayette, Indiana, USA
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70
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Lazo PA, García JL, Gómez-Puertas P, Marcos-Alcalde Í, Arjona C, Villarroel A, González-Sarmiento R, Fons C. Novel Dominant KCNQ2 Exon 7 Partial In-Frame Duplication in a Complex Epileptic and Neurodevelopmental Delay Syndrome. Int J Mol Sci 2020; 21:ijms21124447. [PMID: 32585800 PMCID: PMC7352878 DOI: 10.3390/ijms21124447] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2020] [Revised: 06/17/2020] [Accepted: 06/18/2020] [Indexed: 12/23/2022] Open
Abstract
Complex neurodevelopmental syndromes frequently have an unknown etiology, in which genetic factors play a pathogenic role. This study utilizes whole-exome sequencing (WES) to examine four members of a family with a son presenting, since birth, with epileptic-like crises, combined with cerebral palsy, severe neuromotor and developmental delay, dystonic tetraparexia, axonal motor affectation, and hyper-excitability of unknown origin. The WES study detected within the patient a de novo heterozygous in-frame duplication of thirty-six nucleotides within exon 7 of the human KCNQ2 gene. This insertion duplicates the first twelve amino acids of the calmodulin binding site I. Molecular dynamics simulations of this KCNQ2 peptide duplication, modelled on the 3D structure of the KCNQ2 protein, suggest that the duplication may lead to the dysregulation of calcium inhibition of this protein function.
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Affiliation(s)
- Pedro A. Lazo
- Molecular Mechanisms of Cancer Program, Instituto de Biología Molecular y Celular del Cáncer, Consejo Superior de Investigaciones Científicas (CSIC), Universidad de Salamanca, 30007 Salamanca, Spain; (J.L.G.); (R.G.-S.)
- Instituto de Investigación Biomédica de Salamanca (IBSAL), Hospital Universitario de Salamanca, 30007 Salamanca, Spain
- Correspondence:
| | - Juan L. García
- Molecular Mechanisms of Cancer Program, Instituto de Biología Molecular y Celular del Cáncer, Consejo Superior de Investigaciones Científicas (CSIC), Universidad de Salamanca, 30007 Salamanca, Spain; (J.L.G.); (R.G.-S.)
- Instituto de Investigación Biomédica de Salamanca (IBSAL), Hospital Universitario de Salamanca, 30007 Salamanca, Spain
| | - Paulino Gómez-Puertas
- Centro de Biología Molecular Severo Ochoa, CSIC-Universidad Autónoma de Madrid, Cantoblanco, E-28049 Madrid, Spain; (P.G.-P.); (Í.M.-A.)
| | - Íñigo Marcos-Alcalde
- Centro de Biología Molecular Severo Ochoa, CSIC-Universidad Autónoma de Madrid, Cantoblanco, E-28049 Madrid, Spain; (P.G.-P.); (Í.M.-A.)
- Biosciences Research Institute, School of Experimental Sciences, Universidad Francisco de Vitoria, 28223 Madrid, Spain
| | - Cesar Arjona
- Institut de Recerca Sant Joan de Déu, Esplugues de Llobregat, 08950 Barcelona, Spain; (C.A.); (C.F.)
- Instituto Pediátrico de Enfermedades Raras (IPER), Hospital Sant Joan de Déu, 08950 Barcelona, Spain
| | - Alvaro Villarroel
- Instituto de Biofísica, Consejo Superior de Investigaciones Científicas (CSIC), Universidad del País Vasco, 48940 Bilbao, Spain;
| | - Rogelio González-Sarmiento
- Molecular Mechanisms of Cancer Program, Instituto de Biología Molecular y Celular del Cáncer, Consejo Superior de Investigaciones Científicas (CSIC), Universidad de Salamanca, 30007 Salamanca, Spain; (J.L.G.); (R.G.-S.)
- Instituto de Investigación Biomédica de Salamanca (IBSAL), Hospital Universitario de Salamanca, 30007 Salamanca, Spain
- Unidad de Genética Molecular, Departamento de Medicina, Universidad de Salamanca, 37008 Salamanca, Spain
| | - Carmen Fons
- Institut de Recerca Sant Joan de Déu, Esplugues de Llobregat, 08950 Barcelona, Spain; (C.A.); (C.F.)
- Neurology Department, Hospital Sant Joan de Déu, Sant Joan de Déu Research Institute and CIBERER, Instituto de Salud Carlos III, 08950 Barcelona, Spain
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71
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Cardoso FC. Multi-targeting sodium and calcium channels using venom peptides for the treatment of complex ion channels-related diseases. Biochem Pharmacol 2020; 181:114107. [PMID: 32579958 DOI: 10.1016/j.bcp.2020.114107] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2020] [Revised: 06/13/2020] [Accepted: 06/17/2020] [Indexed: 02/08/2023]
Abstract
Venom peptides are amongst the most exquisite group of bioactive molecules able to alter the normal physiology of organisms. These bioactive peptides penetrate tissues and blood vessels to encounter a number of receptors and ion channels to which they bind with high affinity and execute modulatory activities. Arachnid is the most diverse class of venomous animals often rich in peptides modulating voltage-gated sodium (NaV), calcium (CaV), and potassium (KV) channels. Spider venoms, in particular, contain potent and selective peptides targeting these channels, with a few displaying interesting multi-target properties for NaV and CaV channels underlying disease mechanisms such as in neuropathic pain, motor neuron disease and cancer. The elucidation of the pharmacology and structure-function properties of these venom peptides are invaluable for the development of effective drugs targeting NaV and CaV channels. This perspective discusses spider venom peptides displaying multi-target properties to modulate NaV and CaV channels in regard to their pharmacological features, structure-function relationships and potential to become the next generation of effective drugs to treat neurological disorders and other multi-ion channels related diseases.
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Affiliation(s)
- Fernanda C Cardoso
- Institute for Molecular Bioscience, The University of Queensland, 306 Carmody Rd., St Lucia, QLD AU 4072, Australia
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Haberberger RV, Barry C, Matusica D. Immortalized Dorsal Root Ganglion Neuron Cell Lines. Front Cell Neurosci 2020; 14:184. [PMID: 32636736 PMCID: PMC7319018 DOI: 10.3389/fncel.2020.00184] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2020] [Accepted: 05/28/2020] [Indexed: 12/14/2022] Open
Abstract
Pain is one of the most significant causes of suffering and disability world-wide, and arguably the most burdensome global health challenge. The growing number of patients suffering from chronic pain conditions such as fibromyalgia, complex regional pain syndrome, migraine and irritable bowel syndrome, not only reflect the complexity and heterogeneity of pain types, but also our lack of understanding of the underlying mechanisms. Sensory neurons within the dorsal root ganglia (DRG) have emerged as viable targets for effective chronic pain therapy. However, DRG's contain different classes of primary sensory neurons including pain-associated nociceptive neurons, non-nociceptive temperature sensing, mechanosensory and chemoreceptive neurons, as well as multiple types of immune and endothelial cells. This cell-population heterogeneity makes investigations of individual subgroups of DRG neurons, such as nociceptors, difficult. In attempts to overcome some of these difficulties, a limited number of immortalized DRG-derived cell lines have been generated over the past few decades. In vitro experiments using DRG-derived cell lines have been useful in understanding sensory neuron function. In addition to retaining phenotypic similarities to primary cultured DRG neurons, these cells offer greater suitability for high throughput assays due to ease of culture, maintenance, growth efficiency and cost-effectiveness. For accurate interpretation and translation of results it is critical, however, that phenotypic similarities and differences of DRG-derived cells lines are methodically compared to native neurons. Published reports to date show notable variability in how these DRG-derived cells are maintained and differentiated. Understanding the cellular and molecular differences stemming from different culture methods, is essential to validate past and future experiments, and enable these cells to be used to their full potential. This review describes currently available DRG-derived cell lines, their known sensory and nociceptor specific molecular profiles, and summarize their morphological features related to differentiation and neurite outgrowth.
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Affiliation(s)
- Rainer Viktor Haberberger
- Anatomy & Histology, College of Medicine and Public Health, Flinders Health & Medical Research Institute, Flinders University, Adelaide, SA, Australia
| | - Christine Barry
- Anatomy & Histology, College of Medicine and Public Health, Flinders Health & Medical Research Institute, Flinders University, Adelaide, SA, Australia
| | - Dusan Matusica
- Anatomy & Histology, College of Medicine and Public Health, Flinders Health & Medical Research Institute, Flinders University, Adelaide, SA, Australia
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Tapia CM, Folorunso O, Singh AK, McDonough K, Laezza F. Effects of Deltamethrin Acute Exposure on Nav1.6 Channels and Medium Spiny Neurons of the Nucleus Accumbens. Toxicology 2020; 440:152488. [PMID: 32387285 DOI: 10.1016/j.tox.2020.152488] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2020] [Revised: 04/16/2020] [Accepted: 04/30/2020] [Indexed: 12/19/2022]
Abstract
Exposure to pyrethroids, a popular insecticide class that targets voltage-gated Na+ (Nav) channels, has been correlated to an increase in diagnosis of neurodevelopmental disorders, such as attention deficit hyperactive disorder (ADHD), in children. Dysregulation of medium spiny neurons (MSNs) firing in the nucleus accumbens (NAc) is thought to play a critical role in the pathophysiology of ADHD and other neurodevelopmental disorders. The Nav1.6 channel is the primary molecular determinant of MSN firing and is sensitive to modification by pyrethroids. Building on previous studies demonstrating that deltamethrin (DM), a commonly used pyrethroid, leads to use-dependent enhancement of sodium currents, we characterized the effect of the toxin on long-term inactivation (LTI) of the Nav1.6 channel, a parameter known to affect neuronal firing, and characterized changes in MSN intrinsic excitability. We employed whole-cell patch-clamp electrophysiology to measure sodium currents in HEK-293 cells stably expressing Nav1.6 channels and intrinsic excitability of MSNs in the brain slice preparation. We found that in response to repetitive stimulation acute exposure to 10 μM DM potentiated a build-up of residual sodium currents and modified availability of Nav1.6 by inducing LTI. In the NAc, DM modified MSN intrinsic excitability increasing evoked action potential firing frequency and inducing aberrant action potentials with low amplitude and depolarized voltage threshold, phenotypes that could be explained by DM induced changes on the Nav1.6 channel. These results provide a potential initial mechanism of toxicity of DM that could lead to disruption of the NAc circuitry overtime, increasing the risk of ADHD and other neurodevelopmental disorders.
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Affiliation(s)
- Cynthia M Tapia
- Department of Pharmacology & Toxicology, University of Texas Medical Branch, Galveston, Texas 77555, USA; NIEHS Enviornmental Toxicology Training Program, University of Texas Medical Branch, Galveston, Texas 77555, USA
| | - Oluwarotimi Folorunso
- Department of Pharmacology & Toxicology, University of Texas Medical Branch, Galveston, Texas 77555, USA
| | - Aditya K Singh
- Department of Pharmacology & Toxicology, University of Texas Medical Branch, Galveston, Texas 77555, USA
| | - Kathleen McDonough
- Department of Neuroscience and Cell Biology, University of Texas Medical Branch, Galveston, Texas 77555, USA
| | - Fernanda Laezza
- Department of Pharmacology & Toxicology, University of Texas Medical Branch, Galveston, Texas 77555, USA.
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Zou X, Wang Y, Yu Y, He J, Zhao F, Xi C, Zhang C, Cao Z. BmK NSP, a new sodium channel activator from Buthus martensii Karsch, promotes neurite outgrowth in primary cultured spinal cord neurons. Toxicon 2020; 182:13-20. [PMID: 32353571 DOI: 10.1016/j.toxicon.2020.04.096] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2020] [Revised: 03/26/2020] [Accepted: 04/24/2020] [Indexed: 12/24/2022]
Abstract
Scorpion venom is a rich source of bioactive compounds that affect neuronal excitability by modulating the activities of various channels/receptors. In the current study, guided by a Ca2+ mobilization assay, we purified a new neuroactive peptide designated as BmK NSP (Buthus martensii Karsch neurite-stimulating peptide, MW: 7064.30 Da). The primary structure of BmK NSP was determined by Edman degradation. BmK NSP concentration-dependently elevated intracellular Ca2+ concentration ([Ca2+]i) with an EC50 value of 4.18 μM in primary cultured spinal cord neurons (SCNs). Depletion of extracellular Ca2+ abolished BmK NSP-triggered Ca2+ response. Moreover, we demonstrated that BmK NSP-induced Ca2+ response was partially suppressed by the inhibitors of L-type Ca2+ channels, Na+-Ca2+ exchangers and NMDA receptors and was abolished by voltage-gated sodium channel (VGSC) blocker, tetrodotoxin. Whole-cell patch clamp recording demonstrated that BmK NSP delayed VGSC inactivation (EC50 = 1.10 μM) in SCNs. BmK NSP enhanced neurite outgrowth in a non-monotonic manner that peaked at ~30 nM in SCNs. BmK NSP-promoted neurite outgrowth was suppressed by the inhibitors of L-type Ca2+ channels, NMDA receptors, and VGSCs. Considered together, these data demonstrate that BmK NSP is a new α-scorpion toxin that enhances neurite outgrowth through main routes of Ca2+ influx. Modulation of VGSC activity by α-scorpion toxin might represent a novel strategy to regulate the neurogenesis in SCNs.
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Affiliation(s)
- Xiaohan Zou
- Department of TCM Pharmacology, School of Traditional Chinese Pharmacy, China Pharmaceutical University, Nanjing, Jiangsu, 211198, China
| | - Yujing Wang
- Department of TCM Pharmacology, School of Traditional Chinese Pharmacy, China Pharmaceutical University, Nanjing, Jiangsu, 211198, China
| | - Yiyi Yu
- Department of TCM Pharmacology, School of Traditional Chinese Pharmacy, China Pharmaceutical University, Nanjing, Jiangsu, 211198, China
| | - Jing He
- Department of TCM Pharmacology, School of Traditional Chinese Pharmacy, China Pharmaceutical University, Nanjing, Jiangsu, 211198, China
| | - Fang Zhao
- Department of TCM Pharmacology, School of Traditional Chinese Pharmacy, China Pharmaceutical University, Nanjing, Jiangsu, 211198, China.
| | - Chuchu Xi
- Department of TCM Pharmacology, School of Traditional Chinese Pharmacy, China Pharmaceutical University, Nanjing, Jiangsu, 211198, China
| | - Chi Zhang
- Jiangsu Provincial Supervision & Inspection Center of Green & Degradable Materials, Nanjing Institute of Product Quality Inspection, No. 3 E. Jialingjiang Street, Nanjing, Jiangsu, 210019, China
| | - Zhengyu Cao
- Department of TCM Pharmacology, School of Traditional Chinese Pharmacy, China Pharmaceutical University, Nanjing, Jiangsu, 211198, China.
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Pawlinski L, Krawczyk M, Fiema M, Tobor E, Kiec-Wilk B. Dual-action ambroxol in treatment of chronic pain in Gaucher Disease. Eur J Pain 2020; 24:992-996. [PMID: 31994807 DOI: 10.1002/ejp.1538] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2019] [Revised: 01/24/2020] [Accepted: 01/26/2020] [Indexed: 12/23/2022]
Abstract
A significant number of patients with Gaucher disease (GD) suffer from chronic or acute pain that reduces their quality of life. A mutation in lysosomal enzyme β-glucosidase (GCase) leads to an accumulation of glucocerebroside in the macrophage-lineage cells, causing the development of clinical symptoms. Novel studies have revealed that ambroxol (trans-4-(2-amino-3,5-dibromobenzylamino)-cyclohexanol), the well-known mucolytic drug, acts as a chaperone for the mutant, misfolded enzyme. In addition, as has recently been shown, ambroxol is a Nav 1.8 channel blocker in Aβ, Aδ and unmyelinated C fibres, and therefore reduces the transmission of sensory stimuli from the primary afferent neurons to the dorsal spinal cord. In this way, it can act analgetically. Thus, in addition to broncholytic properties, ambroxol combines two other important functions: it enhances enzyme replacement therapy (ERT) and pain management in patients with GD. We present a 38-year-old female patient with type 3 GD who had reported permanent bone pain in the lumbar-sacral part of the spine for over a year without any pathology evidenced in the undertaken, recommended diagnostic tests. The pain was partly controlled with standard analgesics, that is, paracetamol and tramadol. Ambroxol was introduced at a dose of 150mg/d without a noticeable effect. However, when the dose was increased up to 450mg/d, the intensity of pain diminished and subsided within the following months. Two of three attempts to reduce the dose of ambroxol resulted in a pain relapse within a week, which subsided after resetting the previous, higher dose. This observation of the effects of ambroxol in a GD patient is worth considering for other GD patients with chronic pain.
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Affiliation(s)
- Lukasz Pawlinski
- Clinical Department of Metabolic Diseases, University Hospital in Krakow, Krakow, Poland.,European Reference Network for Hereditary Metabolic Disorders (MetabERN), Udine, Italy
| | - Magdalena Krawczyk
- Clinical Department of Metabolic Diseases, University Hospital in Krakow, Krakow, Poland
| | - Mateusz Fiema
- Clinical Department of Metabolic Diseases, University Hospital in Krakow, Krakow, Poland
| | - Ewa Tobor
- Clinical Department of Metabolic Diseases, University Hospital in Krakow, Krakow, Poland
| | - Beata Kiec-Wilk
- Clinical Department of Metabolic Diseases, University Hospital in Krakow, Krakow, Poland.,European Reference Network for Hereditary Metabolic Disorders (MetabERN), Udine, Italy.,Department of Metabolic Diseases, Jagiellonian University Medical College, Krakow, Poland
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76
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Lorenzo DN. Cargo hold and delivery: Ankyrins, spectrins, and their functional patterning of neurons. Cytoskeleton (Hoboken) 2020; 77:129-148. [PMID: 32034889 DOI: 10.1002/cm.21602] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2020] [Revised: 02/01/2020] [Accepted: 02/03/2020] [Indexed: 01/12/2023]
Abstract
The highly polarized, typically very long, and nonmitotic nature of neurons present them with unique challenges in the maintenance of their homeostasis. This architectural complexity serves a rich and tightly controlled set of functions that enables their fast communication with neighboring cells and endows them with exquisite plasticity. The submembrane neuronal cytoskeleton occupies a pivotal position in orchestrating the structural patterning that determines local and long-range subcellular specialization, membrane dynamics, and a wide range of signaling events. At its center is the partnership between ankyrins and spectrins, which self-assemble with both remarkable long-range regularity and micro- and nanoscale specificity to precisely position and stabilize cell adhesion molecules, membrane transporters, ion channels, and other cytoskeletal proteins. To accomplish these generally conserved, but often functionally divergent and spatially diverse, roles these partners use a combinatorial program of a couple of dozens interacting family members, whose code is not fully unraveled. In a departure from their scaffolding roles, ankyrins and spectrins also enable the delivery of material to the plasma membrane by facilitating intracellular transport. Thus, it is unsurprising that deficits in ankyrins and spectrins underlie several neurodevelopmental, neurodegenerative, and psychiatric disorders. Here, I summarize key aspects of the biology of spectrins and ankyrins in the mammalian neuron and provide a snapshot of the latest advances in decoding their roles in the nervous system.
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Affiliation(s)
- Damaris N Lorenzo
- Department of Cell Biology and Physiology, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
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Struckman HL, Baine S, Thomas J, Mezache L, Mykytyn K, Györke S, Radwański PB, Veeraraghavan R. Super-Resolution Imaging Using a Novel High-Fidelity Antibody Reveals Close Association of the Neuronal Sodium Channel Na V1.6 with Ryanodine Receptors in Cardiac Muscle. MICROSCOPY AND MICROANALYSIS : THE OFFICIAL JOURNAL OF MICROSCOPY SOCIETY OF AMERICA, MICROBEAM ANALYSIS SOCIETY, MICROSCOPICAL SOCIETY OF CANADA 2020; 26:157-165. [PMID: 31931893 PMCID: PMC7061261 DOI: 10.1017/s1431927619015289] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
The voltage-gated sodium channel [pore-forming subunit of the neuronal voltage-gated sodium channel (NaV1.6)] has recently been found in cardiac myocytes. Emerging studies indicate a role for NaV1.6 in ionic homeostasis as well as arrhythmogenesis. Little is known about the spatial organization of these channels in cardiac muscle, mainly due to the lack of high-fidelity antibodies. Therefore, we developed and rigorously validated a novel rabbit polyclonal NaV1.6 antibody and undertook super-resolution microscopy studies of NaV1.6 localization in cardiac muscle. We developed and validated a novel rabbit polyclonal antibody against a C-terminal epitope on the neuronal sodium channel 1.6 (NaV1.6). Raw sera showed high affinity in immuno-fluorescence studies, which was improved with affinity purification. The antibody was rigorously validated for specificity via multiple approaches. Lastly, we used this antibody in proximity ligation assay (PLA) and super-resolution STochastic Optical Reconstruction Microscopy (STORM) studies, which revealed enrichment of NaV1.6 in close proximity to ryanodine receptor (RyR2), a key calcium (Ca2+) cycling protein, in cardiac myocytes. In summary, our novel NaV1.6 antibody demonstrates high degrees of specificity and fidelity in multiple preparations. It enabled multimodal microscopic studies and revealed that over half of the NaV1.6 channels in cardiac myocytes are located within 100 nm of ryanodine receptor Ca2+ release channels.
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Affiliation(s)
- Heather L. Struckman
- Department of Biomedical Engineering, College of Engineering, The Ohio State University, Columbus, OH, US
| | - Stephen Baine
- Dorothy M. Davis Heart and Lung Research Institute, College of Medicine, The Ohio State University Wexner Medical Center, Columbus, OH, US
- Department of Physiology and Cell Biology, College of Medicine, The Ohio State University, Columbus, OH, US
| | - Justin Thomas
- Division of Pharmacy Practice and Sciences, College of Pharmacy, The Ohio State University, Columbus, OH, US
| | - Louisa Mezache
- Department of Biomedical Engineering, College of Engineering, The Ohio State University, Columbus, OH, US
| | - Kirk Mykytyn
- Department of Biological Chemistry and Pharmacology, The Ohio State University, Columbus, OH, US
| | - Sándor Györke
- Dorothy M. Davis Heart and Lung Research Institute, College of Medicine, The Ohio State University Wexner Medical Center, Columbus, OH, US
- Department of Physiology and Cell Biology, College of Medicine, The Ohio State University, Columbus, OH, US
| | - Przemysław B. Radwański
- Dorothy M. Davis Heart and Lung Research Institute, College of Medicine, The Ohio State University Wexner Medical Center, Columbus, OH, US
- Department of Physiology and Cell Biology, College of Medicine, The Ohio State University, Columbus, OH, US
- Division of Pharmacy Practice and Sciences, College of Pharmacy, The Ohio State University, Columbus, OH, US
| | - Rengasayee Veeraraghavan
- Department of Biomedical Engineering, College of Engineering, The Ohio State University, Columbus, OH, US
- Dorothy M. Davis Heart and Lung Research Institute, College of Medicine, The Ohio State University Wexner Medical Center, Columbus, OH, US
- Department of Physiology and Cell Biology, College of Medicine, The Ohio State University, Columbus, OH, US
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Tb1, a Neurotoxin from Tityus bahiensis Scorpion Venom, Induces Epileptic Seizures by Increasing Glutamate Release. Toxins (Basel) 2020; 12:toxins12020065. [PMID: 31973132 PMCID: PMC7076872 DOI: 10.3390/toxins12020065] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2019] [Revised: 12/19/2019] [Accepted: 01/02/2020] [Indexed: 01/02/2023] Open
Abstract
Here, we report the neurotoxic effects aroused by the intracerebral injection (in rats) of Tb1, which is a neurotoxin isolated from Tityus bahiensis scorpion venom. Biochemical analyses have demonstrated that this toxin is similar to the gamma toxin from T. serrulatus, which is a β-scorpion toxin that acts on sodium channels, causing the activation process to occur at more hyperpolarized membrane voltages. Male Wistar rats were stereotaxically implanted with intrahippocampal electrodes and cannulas for electroencephalographic recording and the evaluation of amino acid neurotransmitters levels. Treated animals displayed behavioral and electroencephalographic alterations similar to epileptiform activities, such as myoclonus, wet dog shakes, convulsion, strong discharges, neuronal loss, and increased intracerebral levels of glutamate. Scorpion toxins are important pharmacological tools that are widely employed in ion channel dysregulation studies. The current work contributes to the understanding of channelopathies, particularly epilepsy, which may originate, among other events, from dysfunctional sodium channels, which are the main target of the Tb1 toxin.
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Sills GJ, Rogawski MA. Mechanisms of action of currently used antiseizure drugs. Neuropharmacology 2020; 168:107966. [PMID: 32120063 DOI: 10.1016/j.neuropharm.2020.107966] [Citation(s) in RCA: 230] [Impact Index Per Article: 57.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2019] [Revised: 01/09/2020] [Accepted: 01/12/2020] [Indexed: 02/08/2023]
Abstract
Antiseizure drugs (ASDs) prevent the occurrence of seizures; there is no evidence that they have disease-modifying properties. In the more than 160 years that orally administered ASDs have been available for epilepsy therapy, most agents entering clinical practice were either discovered serendipitously or with the use of animal seizure models. The ASDs originating from these approaches act on brain excitability mechanisms to interfere with the generation and spread of epileptic hyperexcitability, but they do not address the specific defects that are pathogenic in the epilepsies for which they are prescribed, which in most cases are not well understood. There are four broad classes of such ASD mechanisms: (1) modulation of voltage-gated sodium channels (e.g. phenytoin, carbamazepine, lamotrigine), voltage-gated calcium channels (e.g. ethosuximide), and voltage-gated potassium channels [e.g. retigabine (ezogabine)]; (2) enhancement of GABA-mediated inhibitory neurotransmission (e.g. benzodiazepines, tiagabine, vigabatrin); (3) attenuation of glutamate-mediated excitatory neurotransmission (e.g. perampanel); and (4) modulation of neurotransmitter release via a presynaptic action (e.g. levetiracetam, brivaracetam, gabapentin, pregabalin). In the past two decades there has been great progress in identifying the pathophysiological mechanisms of many genetic epilepsies. Given this new understanding, attempts are being made to engineer specific small molecule, antisense and gene therapies that functionally reverse or structurally correct pathogenic defects in epilepsy syndromes. In the near future, these new therapies will begin a paradigm shift in the treatment of some rare genetic epilepsy syndromes, but targeted therapies will remain elusive for the vast majority of epilepsies until their causes are identified. This article is part of the special issue entitled 'New Epilepsy Therapies for the 21st Century - From Antiseizure Drugs to Prevention, Modification and Cure of Epilepsy'.
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Affiliation(s)
- Graeme J Sills
- School of Life Sciences, University of Glasgow, Glasgow, UK.
| | - Michael A Rogawski
- Department of Neurology, School of Medicine, University of California, Davis, Sacramento, CA, USA; Department of Pharmacology, School of Medicine, University of California, Davis, Sacramento, CA, USA
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Kalina RS, Peigneur S, Zelepuga EA, Dmitrenok PS, Kvetkina AN, Kim NY, Leychenko EV, Tytgat J, Kozlovskaya EP, Monastyrnaya MM, Gladkikh IN. New Insights into the Type II Toxins from the Sea Anemone Heteractis crispa. Toxins (Basel) 2020; 12:E44. [PMID: 31936885 PMCID: PMC7020476 DOI: 10.3390/toxins12010044] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2019] [Revised: 01/07/2020] [Accepted: 01/08/2020] [Indexed: 12/23/2022] Open
Abstract
Toxins modulating NaV channels are the most abundant and studied peptide components of sea anemone venom. Three type-II toxins, δ-SHTX-Hcr1f (= RpII), RTX-III, and RTX-VI, were isolated from the sea anemone Heteractis crispa. RTX-VI has been found to be an unusual analog of RTX-III. The electrophysiological effects of Heteractis toxins on nine NaV subtypes were investigated for the first time. Heteractis toxins mainly affect the inactivation of the mammalian NaV channels expressed in the central nervous system (NaV1.1-NaV1.3, NaV1.6) as well as insect and arachnid channels (BgNaV1, VdNaV1). The absence of Arg13 in the RTX-VI structure does not prevent toxin binding with the channel but it has changed its pharmacological profile and potency. According to computer modeling data, the δ-SHTX-Hcr1f binds within the extracellular region of the rNaV1.2 voltage-sensing domain IV and pore-forming domain I through a network of strong interactions, and an additional fixation of the toxin at the channel binding site is carried out through the phospholipid environment. Our data suggest that Heteractis toxins could be used as molecular tools for NaV channel studies or insecticides rather than as pharmacological agents.
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Affiliation(s)
- Rimma S. Kalina
- G.B. Elyakov Pacific Institute of Bioorganic Chemistry, Far Eastern Branch of the Russian Academy of Science, 690022 Vladivostok, Russia; (E.A.Z.); (P.S.D.); (A.N.K.); (N.Y.K.); (E.V.L.); (E.P.K.); (M.M.M.)
| | - Steve Peigneur
- Toxicology and Pharmacology, University of Leuven (KU Leuven), Campus Gasthuisberg, O&N 2, Herestraat~49, P.O. Box 922, 3000 Leuven, Belgium
| | - Elena A. Zelepuga
- G.B. Elyakov Pacific Institute of Bioorganic Chemistry, Far Eastern Branch of the Russian Academy of Science, 690022 Vladivostok, Russia; (E.A.Z.); (P.S.D.); (A.N.K.); (N.Y.K.); (E.V.L.); (E.P.K.); (M.M.M.)
| | - Pavel S. Dmitrenok
- G.B. Elyakov Pacific Institute of Bioorganic Chemistry, Far Eastern Branch of the Russian Academy of Science, 690022 Vladivostok, Russia; (E.A.Z.); (P.S.D.); (A.N.K.); (N.Y.K.); (E.V.L.); (E.P.K.); (M.M.M.)
| | - Aleksandra N. Kvetkina
- G.B. Elyakov Pacific Institute of Bioorganic Chemistry, Far Eastern Branch of the Russian Academy of Science, 690022 Vladivostok, Russia; (E.A.Z.); (P.S.D.); (A.N.K.); (N.Y.K.); (E.V.L.); (E.P.K.); (M.M.M.)
| | - Natalia Y. Kim
- G.B. Elyakov Pacific Institute of Bioorganic Chemistry, Far Eastern Branch of the Russian Academy of Science, 690022 Vladivostok, Russia; (E.A.Z.); (P.S.D.); (A.N.K.); (N.Y.K.); (E.V.L.); (E.P.K.); (M.M.M.)
| | - Elena V. Leychenko
- G.B. Elyakov Pacific Institute of Bioorganic Chemistry, Far Eastern Branch of the Russian Academy of Science, 690022 Vladivostok, Russia; (E.A.Z.); (P.S.D.); (A.N.K.); (N.Y.K.); (E.V.L.); (E.P.K.); (M.M.M.)
| | - Jan Tytgat
- Toxicology and Pharmacology, University of Leuven (KU Leuven), Campus Gasthuisberg, O&N 2, Herestraat~49, P.O. Box 922, 3000 Leuven, Belgium
| | - Emma P. Kozlovskaya
- G.B. Elyakov Pacific Institute of Bioorganic Chemistry, Far Eastern Branch of the Russian Academy of Science, 690022 Vladivostok, Russia; (E.A.Z.); (P.S.D.); (A.N.K.); (N.Y.K.); (E.V.L.); (E.P.K.); (M.M.M.)
| | - Margarita M. Monastyrnaya
- G.B. Elyakov Pacific Institute of Bioorganic Chemistry, Far Eastern Branch of the Russian Academy of Science, 690022 Vladivostok, Russia; (E.A.Z.); (P.S.D.); (A.N.K.); (N.Y.K.); (E.V.L.); (E.P.K.); (M.M.M.)
| | - Irina N. Gladkikh
- G.B. Elyakov Pacific Institute of Bioorganic Chemistry, Far Eastern Branch of the Russian Academy of Science, 690022 Vladivostok, Russia; (E.A.Z.); (P.S.D.); (A.N.K.); (N.Y.K.); (E.V.L.); (E.P.K.); (M.M.M.)
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81
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Ou M, Zhao W, Liu J, Liang P, Huang H, Yu H, Zhu T, Zhou C. The General Anesthetic Isoflurane Bilaterally Modulates Neuronal Excitability. iScience 2019; 23:100760. [PMID: 31926429 PMCID: PMC6956953 DOI: 10.1016/j.isci.2019.100760] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2019] [Revised: 11/16/2019] [Accepted: 12/06/2019] [Indexed: 02/05/2023] Open
Abstract
Volatile anesthetics induce hyperactivity during induction while producing anesthesia at higher concentrations. They also bidirectionally modulate many neuronal functions. However, the neuronal mechanism is unclear. The effects of isoflurane on sodium channel currents were analyzed in acute mouse brain slices, including sodium leak (NALCN) currents and voltage-gated sodium channels (Nav) currents. Isoflurane at sub-anesthetic concentrations increased the spontaneous firing rate of CA3 pyramidal neurons, whereas anesthetic concentrations of isoflurane decreased the firing rate. Isoflurane at sub-anesthetic concentrations enhanced NALCN conductance but minimally inhibited Nav currents. Isoflurane at anesthetic concentrations depressed Nav currents and action potential amplitudes. Isoflurane at sub-anesthetic concentrations depolarized resting membrane potential (RMP) of neurons, whereas hyperpolarized the RMP at anesthetic concentrations. Isoflurane at low concentrations induced hyperactivity in vivo, which was diminished in NALCN knockdown mice. In conclusion, enhancement of NALCN by isoflurane contributes to its bidirectional modulation of neuronal excitability and the hyperactivity during induction. Volatile anesthetic isoflurane exerts bidirectional modulation of neuronal excitability Isoflurane enhances NALCN conductance at sub-anesthetic concentration NALCN knockdown diminishes behavioral hyperactivity during isoflurane induction
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Affiliation(s)
- Mengchan Ou
- Laboratory of Anesthesia & Critical Care Medicine, Translational Neuroscience Center, West China Hospital of Sichuan University, Chengdu 610041, Sichuan, P.R. China; Department of Anesthesiology, West China Hospital of Sichuan University, Chengdu 610041, Sichuan, P.R. China
| | - Wenling Zhao
- Laboratory of Anesthesia & Critical Care Medicine, Translational Neuroscience Center, West China Hospital of Sichuan University, Chengdu 610041, Sichuan, P.R. China; Department of Anesthesiology, West China Hospital of Sichuan University, Chengdu 610041, Sichuan, P.R. China
| | - Jin Liu
- Laboratory of Anesthesia & Critical Care Medicine, Translational Neuroscience Center, West China Hospital of Sichuan University, Chengdu 610041, Sichuan, P.R. China; Department of Anesthesiology, West China Hospital of Sichuan University, Chengdu 610041, Sichuan, P.R. China
| | - Peng Liang
- Department of Anesthesiology, West China Hospital of Sichuan University, Chengdu 610041, Sichuan, P.R. China
| | - Han Huang
- Department of Anesthesiology, West China Second Hospital of Sichuan University, Chengdu 610041, Sichuan, P.R. China
| | - Hai Yu
- Department of Anesthesiology, West China Hospital of Sichuan University, Chengdu 610041, Sichuan, P.R. China
| | - Tao Zhu
- Department of Anesthesiology, West China Hospital of Sichuan University, Chengdu 610041, Sichuan, P.R. China
| | - Cheng Zhou
- Laboratory of Anesthesia & Critical Care Medicine, Translational Neuroscience Center, West China Hospital of Sichuan University, Chengdu 610041, Sichuan, P.R. China; Department of Anesthesiology, West China Hospital of Sichuan University, Chengdu 610041, Sichuan, P.R. China.
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82
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Marine Toxins and Nociception: Potential Therapeutic Use in the Treatment of Visceral Pain Associated with Gastrointestinal Disorders. Toxins (Basel) 2019; 11:toxins11080449. [PMID: 31370176 PMCID: PMC6723473 DOI: 10.3390/toxins11080449] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2019] [Revised: 07/24/2019] [Accepted: 07/26/2019] [Indexed: 12/12/2022] Open
Abstract
Visceral pain, of which the pathogenic basis is currently largely unknown, is a hallmark symptom of both functional disorders, such as irritable bowel syndrome, and inflammatory bowel disease. Intrinsic sensory neurons in the enteric nervous system and afferent sensory neurons of the dorsal root ganglia, connecting with the central nervous system, represent the primary neuronal pathways transducing gut visceral pain. Current pharmacological therapies have several limitations, owing to their partial efficacy and the generation of severe adverse effects. Numerous cellular targets of visceral nociception have been recognized, including, among others, channels (i.e., voltage-gated sodium channels, VGSCs, voltage-gated calcium channels, VGCCs, Transient Receptor Potential, TRP, and Acid-sensing ion channels, ASICs) and neurotransmitter pathways (i.e., GABAergic pathways), which represent attractive targets for the discovery of novel drugs. Natural biologically active compounds, such as marine toxins, able to bind with high affinity and selectivity to different visceral pain molecular mediators, may represent a useful tool (1) to improve our knowledge of the physiological and pathological relevance of each nociceptive target, and (2) to discover therapeutically valuable molecules. In this review we report the most recent literature describing the effects of marine toxin on gastrointestinal visceral pain pathways and the possible clinical implications in the treatment of chronic pain associated with gut diseases.
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83
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Genetic mechanisms of regression in autism spectrum disorder. Neurosci Biobehav Rev 2019; 102:208-220. [DOI: 10.1016/j.neubiorev.2019.04.022] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2018] [Revised: 02/12/2019] [Accepted: 04/28/2019] [Indexed: 12/17/2022]
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84
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Zhao F, Tang Q, Xu J, Wang S, Li S, Zou X, Cao Z. Dehydrocrenatidine Inhibits Voltage-Gated Sodium Channels and Ameliorates Mechanic Allodia in a Rat Model of Neuropathic Pain. Toxins (Basel) 2019; 11:E229. [PMID: 31003411 PMCID: PMC6521113 DOI: 10.3390/toxins11040229] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2019] [Revised: 04/10/2019] [Accepted: 04/15/2019] [Indexed: 12/27/2022] Open
Abstract
Picrasma quassioides (D. Don) Benn, a medical plant, is used in clinic to treat inflammation, pain, sore throat, and eczema. The alkaloids are the main active components in P. quassioides. In this study, we examined the analgesic effect of dehydrocrenatidine (DHCT), a β-carboline alkaloid abundantly found in P. quassioides in a neuropathic pain rat model of a sciatic nerve chronic constriction injury. DHCT dose-dependently attenuated the mechanic allodynia. In acutely isolated dorsal root ganglion, DHCT completely suppressed the action potential firing. Further electrophysiological characterization demonstrated that DHCT suppressed both tetrodotoxin-resistant (TTX-R) and sensitive (TTX-S) voltage-gated sodium channel (VGSC) currents with IC50 values of 12.36 μM and 4.87 µM, respectively. DHCT shifted half-maximal voltage (V1/2) of inactivation to hyperpolarizing direction by ~16.7 mV in TTX-S VGSCs. In TTX-R VGSCs, DHCT shifted V1/2 of inactivation voltage to hyperpolarizing direction and V1/2 of activation voltage to more depolarizing potential by ~23.9 mV and ~12.2 mV, respectively. DHCT preferred to interact with an inactivated state of VGSCs and prolonged the repriming time in both TTX-S and TTX-R VGSCs, transiting the channels into a slow inactivated state from a fast inactivated state. Considered together, these data demonstrated that the analgesic effect of DHCT was likely though the inhibition of neuronal excitability.
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Affiliation(s)
- Fang Zhao
- Jiangsu Key Laboratory of TCM Evaluation and Translational Research, School of Traditional Chinese Pharmacy, China Pharmaceutical University, Nanjing 211198, China.
| | - Qinglian Tang
- Jiangsu Key Laboratory of TCM Evaluation and Translational Research, School of Traditional Chinese Pharmacy, China Pharmaceutical University, Nanjing 211198, China.
| | - Jian Xu
- Jiangsu Key Laboratory of TCM Evaluation and Translational Research, School of Traditional Chinese Pharmacy, China Pharmaceutical University, Nanjing 211198, China.
| | - Shuangyan Wang
- Jiangsu Key Laboratory of TCM Evaluation and Translational Research, School of Traditional Chinese Pharmacy, China Pharmaceutical University, Nanjing 211198, China.
| | - Shaoheng Li
- Jiangsu Key Laboratory of TCM Evaluation and Translational Research, School of Traditional Chinese Pharmacy, China Pharmaceutical University, Nanjing 211198, China.
| | - Xiaohan Zou
- Jiangsu Key Laboratory of TCM Evaluation and Translational Research, School of Traditional Chinese Pharmacy, China Pharmaceutical University, Nanjing 211198, China.
| | - Zhengyu Cao
- Jiangsu Key Laboratory of TCM Evaluation and Translational Research, School of Traditional Chinese Pharmacy, China Pharmaceutical University, Nanjing 211198, China.
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Maatuf Y, Geron M, Priel A. The Role of Toxins in the Pursuit for Novel Analgesics. Toxins (Basel) 2019; 11:toxins11020131. [PMID: 30813430 PMCID: PMC6409898 DOI: 10.3390/toxins11020131] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2019] [Revised: 02/17/2019] [Accepted: 02/20/2019] [Indexed: 12/19/2022] Open
Abstract
Chronic pain is a major medical issue which reduces the quality of life of millions and inflicts a significant burden on health authorities worldwide. Currently, management of chronic pain includes first-line pharmacological therapies that are inadequately effective, as in just a portion of patients pain relief is obtained. Furthermore, most analgesics in use produce severe or intolerable adverse effects that impose dose restrictions and reduce compliance. As the majority of analgesic agents act on the central nervous system (CNS), it is possible that blocking pain at its source by targeting nociceptors would prove more efficient with minimal CNS-related side effects. The development of such analgesics requires the identification of appropriate molecular targets and thorough understanding of their structural and functional features. To this end, plant and animal toxins can be employed as they affect ion channels with high potency and selectivity. Moreover, elucidation of the toxin-bound ion channel structure could generate pharmacophores for rational drug design while favorable safety and analgesic profiles could highlight toxins as leads or even as valuable therapeutic compounds themselves. Here, we discuss the use of plant and animal toxins in the characterization of peripherally expressed ion channels which are implicated in pain.
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Affiliation(s)
- Yossi Maatuf
- The Institute for Drug Research (IDR), School of Pharmacy, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem 9112001, Israel.
| | - Matan Geron
- The Institute for Drug Research (IDR), School of Pharmacy, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem 9112001, Israel.
| | - Avi Priel
- The Institute for Drug Research (IDR), School of Pharmacy, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem 9112001, Israel.
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