DOCSLIB.ORG

Barbiturate Regulation of Kinetic Properties of the Gabaa Receptor Channel of Mouse Spinal Neurones in Culture by Robert L

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Barbiturate Regulation of Kinetic Properties of the Gabaa Receptor Channel of Mouse Spinal Neurones in Culture by Robert L Journal of Physiology (1989), 417, pp. 483-500 483 With 6 text-figures Printed in Great Britain BARBITURATE REGULATION OF KINETIC PROPERTIES OF THE GABAA RECEPTOR CHANNEL OF MOUSE SPINAL NEURONES IN CULTURE BY ROBERT L. MACDONALD, CARL J. ROGERS AND ROY E. TWYMAN From the Department ofNeurology, University ofMichigan Medical Center, Ann Arbor, Michigan 48104, USA (Received 23 May 1988) SUMMARY 1. Barbiturate regulation of the kinetic properties of y-aminobutyric acidA (GABA) receptor channel chloride currents from somata of mouse spinal cord neurones were investigated using whole-cell and excised outside-out patch-clamp recording techniques. 2. GABA (2 1uM), GABA (2 /iM) plus phenobarbitone (PhB) (500 gM) and GABA (2,lM) plus pentobarbitone (PB) (50/,M), applied by pressure ejection from blunt perfusion micropipettes, evoked inward chloride currents when neurones or patches were voltage clamped at -75 mV and the chloride equilibrium potential was 0 mV. GABA receptor channel currents were increased by PhB and PB. 3. Single GABA receptor channel currents were recorded with a main conductance state of 27 pS and a less frequent subconductance state of 16-5 pS. The conductances of the two states were unchanged by the barbiturates. 4. The main conductance state kinetics were analysed. GABA alone or with the barbiturates gated the channel open singly and in groups of openings. 5. The barbiturates increased GABA receptor channel mean open time and shifted frequency histograms of channel open times to longer times. 6. Three exponential functions were required to fit the frequency histograms of GABA receptor channel open times, suggesting that the channel has at least three open states (Or, 02, 03). The time constants for the exponential functions (0-9, 2-7 and 7X8 ms, respectively) were unchanged by the barbiturates. The increases in mean open times and the shifts of the open-time frequency histograms by the barbiturates were due to a reduction in relative frequency of occurrence of the two short open states (O1 and 02) and to an increase in the relative frequency of occurrence of the longest open state (03). 7. Frequency histograms of GABA receptor channel closed times were fitted with five exponential functions, suggesting that the channel has multiple closed states. None of the time constants nor areas of the exponential functions were significantly changed by the barbiturates. 8. For analysis, a burst was defined as openings surrounded by closures greater than a critical closed time, tc, of 5 ms. For GABA (2 ,UM), frequency histograms of GABA receptor channel bursts were fitted with three exponential functions, NIS 7(X)1 16-2> 484 R. L. MACDONALD, C. J. ROGERS AND R. E. TWYMAN suggesting that the channel has three burst states (B1, B2, B3). The B1 burst state was probably a single opening to the 01 open state while the B2 and B3 burst states were probably composed of multiple openings to the 02 and 03 open states. With both barbiturates, the relative frequency of occurrence of the two shortest burst states (B1 and B2) was reduced and that of the longest burst state (B3) was increased. The time constant of the B3 burst state was increased slightly by the barbiturates. 9. We suggest that barbiturates increase GABA receptor channel current by increasing the relative frequency of occurrence of the long (B3) bursts which contain multiple long openings and decreasing the relative proportion of shorter (B1 and B2) bursts which contain shorter openings. This results in an increase in GABA receptor channel apparent mean open time and mean burst duration. Barbiturates do not measurably alter the closing rates of the open states, and therefore, do not alter their mean open times. Rather, barbiturates alter the rate constants which regulate entry into the three open states, such that entry into the longest, stable open state (03) is favoured over the two shorter and less stable open states (01 and 02)- INTRODUCTION The postsynaptic y-aminobutyric acidA (GABA) receptor channel is composed of an oligomeric complex of polypeptide subunits which form a chloride channel associated with binding sites for GABA, benzodiazepines and barbiturates (Olsen, 1982; Schofield, Darlison, Fujita, Burt, Stephenson, Rodriguez, Rhee, Rama- chandran, Reale, Glencorse, Seeburg & Barnard, 1987). GABA binds to the receptor and gates open the chloride channel (Curtis, H6sli, Johnston & Johnston, 1968; Hamill, Bormann & Sakmann, 1983). Barbiturates potentiate the inhibitory effects of GABA in the vertebrate central nervous system (Schmidt, 1963; Nicoll, 1972; Ransom & Barker, 1976; Macdonald & Barker, 1979). Based on studies using the noise analysis technique, it was proposed that: (1) the GABA receptor channel opens into a single open state with exponentially distributed open durations and (2) barbiturates potentiate GABAergic inhibition by increasing the mean duration of the single open state without altering the frequency of channel opening or the channel conductance (Barker & McBurney, 1979; Study & Barker, 1981; Barker, McBurney & MacDonald, 1982). However, the resolution of the noise analysis technique is low. Using the single-channel recording technique which has a higher temporal resolution (Hamill, Marty, Neher, Sakmann & Sigworth, 1981), single GABA receptor channel currents have been recorded and shown to be more complex (Jackson, Lecar, Mathers & Barker, 1982; Hamill et al. 1983; Sakmann, Hamill & Bormann, 1983; Bormann & Clapham, 1985; Martin, 1985; Mathers, 1985a; Bormann, Hamill & Sakmann, 1987; Macdonald, Rogers & Twyman, 1989). The GABA receptor channel has been shown to have multiple open and closed states (Macdonald et al. 1989) and to open in bursts (Hamill et al. 1983). The effect of barbiturates on the kinetic properties of GABA receptor channels has not been determined. We have used whole-cell and outside-out patch-clamp recording techniques to study the regulation of GABA receptor channel currents by the BARBITURATE MODULATION OF GABA Cl- CHANNELS 485 barbiturates phenobarbitone (PhB) and pentobarbitone (PB), using mouse spinal cord neurones grown in cell culture. METHODS Cell culture A single-cell suspension of neurones from mechanically dissociated spinal cords, dissected from 10 to 12-day-old murine fetuses, was grown in culture medium as previously described (Ransom, Neale, Henkart, Bullock & Nelson, 1977; Macdonald et al. 1989). The mothers were killed by cervical dislocation under CO2 narcosis prior to removal of the fetuses. Cultures were maintained for 2-5 weeks prior to being used in these experiments. Bathing and recording solutions The same extracellular and intrapipette solutions consisting of a symmetric chloride salt solution were used for both whole-cell and excised outside-out recordings. The extracellular solution consisted of (in mM): 142 NaCl, 8-1 KCI, 1 CaCl2, 6 MgCl2, 10 glucose, 10 Na+-HEPES (pH 7 4). The intrapipette solution consisted of (in mM): 153 KCI, 1 MgCl2, 10 Na+-HEPES, 5 EGTA, 1 NaOH, 2 KOH (pH 74). The specific glycine receptor antagonist strychnine (200 nM) (Sigma Chemical Co., St Louis, MO, USA) was added to all solutions to ensure that no glycine receptor channel currents were included in the analyses. Recordings were performed at room temperature (20-23 °C). This combination of extracellular and intrapipette solutions resulted in a chloride equilibrium potential (Ec1) of0 mV and a potassium equilibrium potential (EK) of -75 mV. Micropipettes Patch recording micropipettes were fabricated up to 24 h prior to use. Drugs and GABA were applied from pressure ejection or diffusion micropipettes. To avoid dilution in the drug micropipette tips, the drug micropipettes were removed from the bathing solution whenever the drugs were not being applied. Prior to application, a pressure pulse (5-10 s) was applied distant from the recording site to eject diluted solution from the micropipette tip. Equipment Both whole-cell and patch-clamp recordings were performed using a Model L/M EPC-7 amplifier (LIST-Medical Instruments, Darmstadt, FRG). For whole-cell recordings, responses were low-pass filtered (3 dB at 600 Hz, 8-pole Butterworth) (A.P. Circuit Corporation. New York, NY, USA) and recorded on a Gould chart recorder (Gould Inc., Cleveland, OH, USA). Patch-clamp command potentials and single-channel currents were recorded on a video cassette recording system (VCR) (SONY SL-2700, modified to 0-20 kHz) via a digital audio processor (SONY PCM-501 ES, 14-bit, 44 kHz). Simultaneously, these data were recorded on a chart recorder (Gould Inc.) using a low- pass (3 dB at 1 kHz) 8-pole Bessel filter (Frequency Devices, Haverhill, MA, USA). For single- channel analysis the data were played back from the VCR system and digitized (8 kHz, 14 bit, Tecmar A/D converter, Cleveland, OH, USA) for computer (80386 based processors) analysis with a low-pass (3 dB at 1 kHz), 8-pole Bessel filter interposed. Digitized data segments ranged in length from 20-25 s. All recordings were performed at room temperature (20-23 °C). Drug application GABA, PhB and PB were obtained from Sigma Chemical Co. GABA (2 FM) was prepared as previously described and applied using pressure micropipettes (Nowak, Young & Macdonald, 1982). The barbiturates PhB and PB were dissolved in solution and serial dilutions provided a final concentration of 500 /M for PhB and 50,uM for PB. These concentrations have been shown previously to enhance GABA responses on mouse spinal cord neurones in cell culture without directly activating GABA receptor channel current (Macdonald & Barker, 1978; Schulz & Macdonald, 1981). A mixture of GABA (2 /M) and barbiturate was applied to the neurone or patch 486 R. L. MACDONALD, C. J. ROGERS AND R. E. TWYMAN membrane via pressure ejection micropipettes in the presence of a diffusion pipette containing the barbiturate. Micropipettes were moved to within 50 ,um of the neurone or membrane only during the time of each application. Whole-cell and outside-out patch recording Whole-cell and excised outside-out patch recording techniques were similar to those of Hamill et al.
Load more

Recommended publications
  • Ivermectin Interacts with an Intersubunit Transmembrane Domain of the Glycine Receptor T
    Ivermectin interacts with an intersubunit transmembrane domain of the glycine receptor T. Lynagh, T.I. Webb and J.W.Lynch, Queensland Brain Institute,Building 79, The University of Queensland, St Lucia, QLD 4072, Australia. Ivermectin is a widely-used anti-parasitic drug that is effective against nematodes and insects. It paralyses and starves nematodes by activating inhibitory currents at glutamate-gated chloride channels (GluCl). It also activates other members of the Cys-loop ligand-gated ion channel superfamily including the human glycine receptors (GlyR). The location of the ivermectin binding site on these receptors is not known. Homomeric and heteromeric Cys-loop receptors are formed by fivesubunits that each contain a large N-terminal ligand-binding domain and four membrane-spanning helices (M1-M4). Werecently showed that ivermectin sensitivity at GluCls and GlyRs depends on the amino acid identity at a particular location in the third transmembrane (M3) domain (GlyR Ala288). Wehypothesized that tryptophan substitution of residues vicinal to Ala288 might also impair activation by ivermectin and provide a structural basis for understanding the binding interaction between iv ermectin and GlyR. We used site-directed mutagenesis to generate several GlyRs containing a bulkytryptophan residue in a domain formed by M3 (including Ala288) from one subunit and M1 from an adjacent subunit, according to the high-resolution structures of analogous proteins. HEK-293 cells were transfected with wild-type (WT) or mutant GlyR DNAand sensitivity to ivermectin was measured by recording ivermectin-mediated current magnitudes using whole cell patch clamp recording. Several mutants showed 2-4-fold shifts in EC50 values for activation by ivermectin.
    [Show full text]
  • A Potential Approach for Treating Pain by Augmenting Glycine-Mediated Spinal Neurotransmission and Blunting Central Nociceptive Signaling
    biomolecules Review Inhibition of Glycine Re-Uptake: A Potential Approach for Treating Pain by Augmenting Glycine-Mediated Spinal Neurotransmission and Blunting Central Nociceptive Signaling Christopher L. Cioffi Departments of Basic and Clinical Sciences and Pharmaceutical Sciences, Albany College of Pharmacy and Health Sciences, Albany, NY 12208, USA; christopher.cioffi@acphs.edu; Tel.: +1-518-694-7224 Abstract: Among the myriad of cellular and molecular processes identified as contributing to patho- logical pain, disinhibition of spinal cord nociceptive signaling to higher cortical centers plays a critical role. Importantly, evidence suggests that impaired glycinergic neurotransmission develops in the dorsal horn of the spinal cord in inflammatory and neuropathic pain models and is a key maladaptive mechanism causing mechanical hyperalgesia and allodynia. Thus, it has been hypothesized that pharmacological agents capable of augmenting glycinergic tone within the dorsal horn may be able to blunt or block aberrant nociceptor signaling to the brain and serve as a novel class of analgesics for various pathological pain states. Indeed, drugs that enhance dysfunctional glycinergic transmission, and in particular inhibitors of the glycine transporters (GlyT1 and GlyT2), are generating widespread + − interest as a potential class of novel analgesics. The GlyTs are Na /Cl -dependent transporters of the solute carrier 6 (SLC6) family and it has been proposed that the inhibition of them presents a Citation: Cioffi, C.L. Inhibition of possible mechanism
    [Show full text]
  • GABA Receptors
    D Reviews • BIOTREND Reviews • BIOTREND Reviews • BIOTREND Reviews • BIOTREND Reviews Review No.7 / 1-2011 GABA receptors Wolfgang Froestl , CNS & Chemistry Expert, AC Immune SA, PSE Building B - EPFL, CH-1015 Lausanne, Phone: +41 21 693 91 43, FAX: +41 21 693 91 20, E-mail: [email protected] GABA Activation of the GABA A receptor leads to an influx of chloride GABA ( -aminobutyric acid; Figure 1) is the most important and ions and to a hyperpolarization of the membrane. 16 subunits with γ most abundant inhibitory neurotransmitter in the mammalian molecular weights between 50 and 65 kD have been identified brain 1,2 , where it was first discovered in 1950 3-5 . It is a small achiral so far, 6 subunits, 3 subunits, 3 subunits, and the , , α β γ δ ε θ molecule with molecular weight of 103 g/mol and high water solu - and subunits 8,9 . π bility. At 25°C one gram of water can dissolve 1.3 grams of GABA. 2 Such a hydrophilic molecule (log P = -2.13, PSA = 63.3 Å ) cannot In the meantime all GABA A receptor binding sites have been eluci - cross the blood brain barrier. It is produced in the brain by decarb- dated in great detail. The GABA site is located at the interface oxylation of L-glutamic acid by the enzyme glutamic acid decarb- between and subunits. Benzodiazepines interact with subunit α β oxylase (GAD, EC 4.1.1.15). It is a neutral amino acid with pK = combinations ( ) ( ) , which is the most abundant combi - 1 α1 2 β2 2 γ2 4.23 and pK = 10.43.
    [Show full text]
  • Targeting Glycine Reuptake in Alcohol Seeking and Relapse
    JPET Fast Forward. Published on January 24, 2018 as DOI: 10.1124/jpet.117.244822 This article has not been copyedited and formatted. The final version may differ from this version. TITLE PAGE Targeting Glycine Reuptake in Alcohol Seeking and Relapse Valentina Vengeliene, Martin Roßmanith, Tatiane T. Takahashi, Daniela Alberati, Berthold Behl, Anton Bespalov, Rainer Spanagel Downloaded from The primary laboratory of origin: Institute of Psychopharmacology, Central Institute of jpet.aspetjournals.org Mental Health, Faculty of Medicine Mannheim, Heidelberg University, Germany; at ASPET Journals on September 30, 2021 VV, MR, TTT, RS: Institute of Psychopharmacology, Central Institute of Mental Health, Faculty of Medicine Mannheim, Heidelberg University, Germany; DA: Roche Pharma Research and Early Development, Neuroscience, Ophthalmology and Rare Diseases, Roche Innovation Center Basel, CH-4070 Basel, Switzerland; BB, AB: Department of Neuroscience Research, AbbVie Deutschland GmbH & Co. KG, Ludwigshafen, Germany; AB: Department of Psychopharmacology, Pavlov Medical University, St Petersburg, Russia JPET #244822 JPET Fast Forward. Published on January 24, 2018 as DOI: 10.1124/jpet.117.244822 This article has not been copyedited and formatted. The final version may differ from this version. RUNNING TITLE GlyT1 in Alcohol Seeking and Relapse Corresponding author with complete address: Valentina Vengeliene, Institute of Psychopharmacology, Central Institute of Mental Health (CIMH), J5, 68159 Mannheim, Germany Email: [email protected], phone: +49-621-17036261; fax: +49-621- Downloaded from 17036255 jpet.aspetjournals.org The number of text pages: 33 Number of tables: 0 Number of figures: 6 Number of references: 44 at ASPET Journals on September 30, 2021 Number of words in the Abstract: 153 Number of words in the Introduction: 729 Number of words in the Discussion: 999 A recommended section assignment to guide the listing in the table of content: Drug Discovery and Translational Medicine 2 JPET #244822 JPET Fast Forward.
    [Show full text]
  • Molecular Basis of the Alternative Recruitment of GABAA Versus Glycine Receptors Through Gephyrin
    ARTICLE Received 19 Aug 2014 | Accepted 4 Nov 2014 | Published 22 Dec 2014 DOI: 10.1038/ncomms6767 Molecular basis of the alternative recruitment of GABAA versus glycine receptors through gephyrin Hans Michael Maric1,2,*, Vikram Babu Kasaragod1,*, Torben Johann Hausrat3, Matthias Kneussel3, Verena Tretter4, Kristian Strømgaard2 & Hermann Schindelin1 g-Aminobutyric acid type A and glycine receptors (GABAARs, GlyRs) are the major inhibitory neurotransmitter receptors and contribute to many synaptic functions, dysfunctions and human diseases. GABAARs are important drug targets regulated by direct interactions with the scaffolding protein gephyrin. Here we deduce the molecular basis of this interaction by chemical, biophysical and structural studies of the gephyrin–GABAAR a3 complex, revealing that the N-terminal region of the a3 peptide occupies the same binding site as the GlyR b subunit, whereas the C-terminal moiety, which is conserved among all synaptic GABAAR a subunits, engages in unique interactions. Thermodynamic dissections of the gephyrin– receptor interactions identify two residues as primary determinants for gephyrin’s subunit preference. This first structural evidence for the gephyrin-mediated synaptic accumulation of GABAARs offers a framework for future investigations into the regulation of inhibitory synaptic strength and for the development of mechanistically and therapeutically relevant compounds targeting the gephyrin–GABAAR interaction. 1 Rudolf Virchow Center for Experimental Biomedicine, University of Wu¨rzburg, Josef-Schneider-Strae 2, Building D15, D-97080 Wu¨rzburg, Germany. 2 Department of Drug Design and Pharmacology, University of Copenhagen, Universitetsparken 2, DK-2100 Copenhagen, Denmark. 3 Center for Molecular Neurobiology, ZMNH, University Medical Center Hamburg-Eppendorf, D-20251 Hamburg, Germany. 4 Department of General Anesthesia and Intensive Care, Medical University Vienna, Wa¨hringer Gu¨rtel 18-20, 1090 Vienna, Austria.
    [Show full text]
  • Increased NMDA Receptor Inhibition at an Increased Sevoflurane MAC Robert J Brosnan* and Roberto Thiesen
    Brosnan and Thiesen BMC Anesthesiology 2012, 12:9 http://www.biomedcentral.com/1471-2253/12/9 RESEARCH ARTICLE Open Access Increased NMDA receptor inhibition at an increased Sevoflurane MAC Robert J Brosnan* and Roberto Thiesen Abstract Background: Sevoflurane potently enhances glycine receptor currents and more modestly decreases NMDA receptor currents, each of which may contribute to immobility. This modest NMDA receptor antagonism by sevoflurane at a minimum alveolar concentration (MAC) could be reciprocally related to large potentiation of other inhibitory ion channels. If so, then reduced glycine receptor potency should increase NMDA receptor antagonism by sevoflurane at MAC. Methods: Indwelling lumbar subarachnoid catheters were surgically placed in 14 anesthetized rats. Rats were anesthetized with sevoflurane the next day, and a pre-infusion sevoflurane MAC was measured in duplicate using a tail clamp method. Artificial CSF (aCSF) containing either 0 or 4 mg/mL strychnine was then infused intrathecally at 4 μL/min, and the post-infusion baseline sevoflurane MAC was measured. Finally, aCSF containing strychnine (either 0 or 4 mg/mL) plus 0.4 mg/mL dizocilpine (MK-801) was administered intrathecally at 4 μL/min, and the post- dizocilpine sevoflurane MAC was measured. Results: Pre-infusion sevoflurane MAC was 2.26%. Intrathecal aCSF alone did not affect MAC, but intrathecal strychnine significantly increased sevoflurane requirement. Addition of dizocilpine significantly decreased MAC in all rats, but this decrease was two times larger in rats without intrathecal strychnine compared to rats with intrathecal strychnine, a statistically significant (P < 0.005) difference that is consistent with increased NMDA receptor antagonism by sevoflurane in rats receiving strychnine.
    [Show full text]
  • Hb-S-07 Effect of Some Components in Green Tea Extract on Brain
    ~ 0'0 The 3rd International Conference on O-CIIA{Tea) Culture and Science 00iA HB-S-07 =========---------------_.~ Effect ofsome components in green tea extract on brain neurotransmitters or functions in rats Hidehiko Yokogoshi Laboratory ofNutritional Biochemistry, CaE Program in the 21 st Century, The University ofShizuoka Summary. In green tea extract, some ingredients with much physiology activity are induced in catechin, caffeine, vitamins, but the amino acid is induced, too. For amino acids peculiar to green tea, there are theanine, r-glutamylethylamide, and r­ aminobutyric acid (GABA) increasing and decreasing again by the process ofthe processed tea is included in particular. These amino acids are derivatives of glutamic acid, which is one ofthe major neurotransmitters in the brain. I examined the effect of these amino acids on brain neurotransmitters, especially serotonin and catecholamines. Then, dopamine release from striatum are siginificantly stimulated by the administration theanine. Therefore, relationships between dopamine release and some inhibitory neurotransmitters. Also, some kinds ofbehavior after the administration of theanine or GABA were examined. I will show you some results. Keywords: L-theanine, dopamine, glycine, GABA, microdialysis Recently, many studies have shown that green tea and various green tea leaf components such as catechins, caffeine and y-aminobutyric acid (GABA) have physiological and pharmacological actions, and more attention has been paid to the effects ofgreen tea ingredients by the public. In particular, GABA is known as an inhibitory neurotransmitter present almost exclusively in the central nervous system (Brambilla et aI., 2003), and GABAergic dysfunction causes mood disorders or neurological disorders such as seizures (Wong et aI., 2003).
    [Show full text]
  • Towards Quantum-Chemical Modeling of the Activity of Anesthetic Compounds
    International Journal of Molecular Sciences Review Towards Quantum-Chemical Modeling of the Activity of Anesthetic Compounds Janusz Cukras 1 and Joanna Sadlej 2,* 1 Laboratory of Spectroscopy and Intermolecular Interactions, Department of Chemistry, University of Warsaw, Pasteura 1, 02-093 Warsaw, Poland; [email protected] 2 Faculty of Mathematics and Natural Sciences, Cardinal Stefan Wyszynski University, Wójcickiego 1/3, 01-938 Warsaw, Poland * Correspondence: [email protected] Abstract: The modeling of the activity of anesthetics is a real challenge because of their unique electronic and structural characteristics. Microscopic approaches relevant to the typical features of these systems have been developed based on the advancements in the theory of intermolecular interactions. By stressing the quantum chemical point of view, here, we review the advances in the field highlighting differences and similarities among the chemicals within this group. The binding of the anesthetics to their partners has been analyzed by Symmetry-Adapted Perturbation Theory to provide insight into the nature of the interaction and the modeling of the adducts/complexes allows us to rationalize their anesthetic properties. A new approach in the frame of microtubule concept and the importance of lipid rafts and channels in membranes is also discussed. Keywords: anesthetics; xenon; intermolecular interactions; DFT; molecular dynamics; ONIOM; SAPT; lipid rafts; GABAA; NMDA; Gly; microtubules; TREK-1 Citation: Cukras, J.; Sadlej, J. Towards Quantum-Chemical Modeling of the Activity of 1. Introduction Anesthetic Compounds. Int. J. Mol. The discovery of general anesthesia (GA) is a fundamental achievement for the de- Sci. 2021, 22, 9272. https://doi.org/ velopment of contemporary biochemistry and biomedical science.
    [Show full text]
  • Glycine Receptor Α3 and Α2 Subunits Mediate Tonic and Exogenous Agonist-Induced Currents in Forebrain
    Glycine receptor α3 and α2 subunits mediate tonic and PNAS PLUS exogenous agonist-induced currents in forebrain Lindsay M. McCrackena,1, Daniel C. Lowesb,1, Michael C. Sallinga, Cyndel Carreau-Vollmera, Naomi N. Odeana, Yuri A. Blednovc, Heinrich Betzd, R. Adron Harrisc, and Neil L. Harrisona,b,2 aDepartment of Anesthesiology, Columbia University College of Physicians and Surgeons, New York, NY 10032; bDepartment of Pharmacology, Columbia University College of Physicians and Surgeons, New York, NY 10032; cThe Waggoner Center for Alcohol and Addiction Research, The University of Texas at Austin, Austin, TX 78712; and dMax Planck Institute for Medical Research, 69120 Heidelberg, Germany Edited by Solomon H. Snyder, Johns Hopkins University School of Medicine, Baltimore, MD, and approved July 17, 2017 (received for review March 14, 2017) Neuronal inhibition can occur via synaptic mechanisms or through Synaptic GlyRs are heteropentamers consisting of different α tonic activation of extrasynaptic receptors. In spinal cord, glycine subunits (α1–α4) coassembled with the β subunit (28), which is mediates synaptic inhibition through the activation of heteromeric obligatory for synaptic localization due to its tight interaction glycine receptors (GlyRs) composed primarily of α1andβ subunits. with the anchoring protein gephyrin (29). GlyR α subunits exist Inhibitory GlyRs are also found throughout the brain, where GlyR in many higher brain regions (30) and may include populations α2andα3 subunit expression exceeds that of α1, particularly in of homopentameric GlyRs expressed in the absence of β subunits forebrain structures, and coassembly of these α subunits with the (31, 32). β subunit appears to occur to a lesser extent than in spinal cord.
    [Show full text]
  • Calcium-Engaged Mechanisms of Nongenomic Action of Neurosteroids
    Calcium-engaged Mechanisms of Nongenomic Action of Neurosteroids The Harvard community has made this article openly available. Please share how this access benefits you. Your story matters Citation Rebas, Elzbieta, Tomasz Radzik, Tomasz Boczek, and Ludmila Zylinska. 2017. “Calcium-engaged Mechanisms of Nongenomic Action of Neurosteroids.” Current Neuropharmacology 15 (8): 1174-1191. doi:10.2174/1570159X15666170329091935. http:// dx.doi.org/10.2174/1570159X15666170329091935. Published Version doi:10.2174/1570159X15666170329091935 Citable link http://nrs.harvard.edu/urn-3:HUL.InstRepos:37160234 Terms of Use This article was downloaded from Harvard University’s DASH repository, and is made available under the terms and conditions applicable to Other Posted Material, as set forth at http:// nrs.harvard.edu/urn-3:HUL.InstRepos:dash.current.terms-of- use#LAA 1174 Send Orders for Reprints to [email protected] Current Neuropharmacology, 2017, 15, 1174-1191 REVIEW ARTICLE ISSN: 1570-159X eISSN: 1875-6190 Impact Factor: 3.365 Calcium-engaged Mechanisms of Nongenomic Action of Neurosteroids BENTHAM SCIENCE Elzbieta Rebas1, Tomasz Radzik1, Tomasz Boczek1,2 and Ludmila Zylinska1,* 1Department of Molecular Neurochemistry, Faculty of Health Sciences, Medical University of Lodz, Poland; 2Boston Children’s Hospital and Harvard Medical School, Boston, USA Abstract: Background: Neurosteroids form the unique group because of their dual mechanism of action. Classically, they bind to specific intracellular and/or nuclear receptors, and next modify genes transcription. Another mode of action is linked with the rapid effects induced at the plasma membrane level within seconds or milliseconds. The key molecules in neurotransmission are calcium ions, thereby we focus on the recent advances in understanding of complex signaling crosstalk between action of neurosteroids and calcium-engaged events.
    [Show full text]
  • The Role of Glycinergic Transmission in the Pathogenesis of Alcohol
    Postepy Hig Med Dosw (online), 2018; 72: 587-593 www.phmd.pl e-ISSN 1732-2693 Review Received: 30.08.2017 Accepted: 18.01.2018 The Role of Glycinergic Transmission in the Published: 06.07.2018 Pathogenesis of Alcohol Abuse Rola przekaźnictwa glicynowego w patogenezie nadużywania alkoholu Przemysław Zakowicz, Radosław Kujawski, Przemysław Mikołajczak Department of Pharmacology, Poznań University of Medical Sciences Summary Alcoholism is a severe social and medical problem. Inadequate ethanol (EtOH) consumption results in acute and chronic conditions, which lead to many hospitalizations and generate considerable costs in healthcare. Alcoholism undoubtedly needs to be thoroughly described, especially in relation to the molecular mechanism of addiction. The current opinion about the pathogenesis of EtOH abuse is mainly based on the dopaminergic theory of addiction, connec- ted with the impaired function of the dopaminergic transmission in the brain’s reward system. Moreover, recent evidence suggests that the potential role in alcohol activity is played also by glycinergic transmission, based inter alia on inhibitory glycine receptors (GlyRs) sensitive to this simplest amino acid. GlyRs are pentameric, ionotropic receptors from ligand-gated ion channel family and facilitate membrane permeability to chloride ions. The receptors are widely present in the human body and spread to the peripheral and central nervous system, where they are engaged in several processes, especially in the regulation of nociception, movement control and, possibly, also they are responsible for controlling the brain’s reward system involved in the pathogenesis of addiction. The last localization seems to be really important and consists of a new insight into the search for novel substances to prevent or cure the consequences of EtOH abuse.
    [Show full text]
  • Glycine Transporter 1 Is a Target for the Treatment of Epilepsy
    Neuropharmacology 99 (2015) 554e565 Contents lists available at ScienceDirect Neuropharmacology journal homepage: www.elsevier.com/locate/neuropharm Glycine transporter 1 is a target for the treatment of epilepsy Hai-Ying Shen a, Erwin A. van Vliet b, Kerry-Ann Bright a, Marissa Hanthorn a, * Nikki K. Lytle a, Jan Gorter c, Eleonora Aronica b, c, d, Detlev Boison a, a Robert Stone Dow Neurobiology Laboratories, Legacy Research Institute, Portland, OR 97232, USA b Department of (Neuro)Pathology, Academic Medical Center, University of Amsterdam, The Netherlands c Swammerdam Institute for Life Sciences, Center for Neuroscience, University of Amsterdam, The Netherlands d SEIN e Stichting Epilepsie Instellingen Nederland, Heemstede, The Netherlands article info abstract Article history: Glycine is the major inhibitory neurotransmitter in brainstem and spinal cord, whereas in hippocampus Received 3 June 2015 glycine exerts dual modulatory roles on strychnine-sensitive glycine receptors and on the strychnine- Received in revised form insensitive glycineB site of the N-methyl-D-aspartate receptor (NMDAR). In hippocampus, the synaptic 27 July 2015 availability of glycine is largely under control of glycine transporter 1 (GlyT1). Since epilepsy is a disorder Accepted 19 August 2015 of disrupted network homeostasis affecting the equilibrium of various neurotransmitters and neuro- Available online 21 August 2015 modulators, we hypothesized that changes in hippocampal GlyT1 expression and resulting disruption of glycine homeostasis might be implicated in the pathophysiology of epilepsy. Using two different rodent Keywords: e Temporal lobe epilepsy models of temporal lobe epilepsy (TLE) the intrahippocampal kainic acid model of TLE in mice, and the e fi Seizures rat model of tetanic stimulation-induced TLE we rst demonstrated robust overexpression of GlyT1 in Glycine transporter 1 the hippocampal formation, suggesting dysfunctional glycine signaling in epilepsy.
    [Show full text]