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Ziemba PM, Mueck A, Gisselmann G, Stoertkuhl KF. Functional expression and ligand identification of homo- and heteromeric Drosophila melanogaster CO2 receptors in the Xenopus laevis oocyte system. PLoS One 2023; 18:e0295404. [PMID: 38157355 PMCID: PMC10756536 DOI: 10.1371/journal.pone.0295404] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2023] [Accepted: 11/20/2023] [Indexed: 01/03/2024] Open
Abstract
Carbon dioxide (CO2) is an important olfactory cue in Drosophila melanogaster and can elicit both attractive and aversive behaviors. It is detected by gustatory receptors, Gr21a and Gr63a, found in the ab1C neuron in basiconic sensilla on the third antennal segment. Volatile substances that modulate the receptors' function are of interest for pest control. While several substances block ab1C neurons or mimic the activating effect of carbon dioxide, it is not known if these substances are indeed ligands of the CO2 receptor or might act on other proteins in the receptor neuron. In this study, we used the recombinant Xenopus laevis expression system and two-electrode voltage-clamp technology to investigate the receptor function. We found that application of sodium bicarbonate evokes large inward currents in oocytes co-expressing Gr21a and Gr63a. The receptors most likely form hetromultimeric complexes. Homomultimeric receptors of Gr21a or Gr63a are sufficient for receptor functionality, although oocytes gave significantly lower current responses compared to the probable heteromultimeric receptor. We screened for putative blockers of the sodium bicarbonate response and confirmed that some of the substances identified by spike recordings of olfactory receptor neurons, such as 1-hexanol, are also blockers in the Xenopus oocyte system. We also identified a new blocking substance, citronellol, which is related to insect repellents. Many substances that activate receptor neurons were inactive in the Xenopus oocyte system, indicating that they may not be ligands for the receptor, but may act on other proteins. However, methyl pyruvate and n-hexylamine were found to be activators of the recombinant Gr21a/Gr63a receptor.
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Affiliation(s)
- Paul M. Ziemba
- AG Physiology of Senses, Ruhr-University Bochum, Bochum, North Rhine-Westphalia, Germany
| | - Alina Mueck
- AG Physiology of Senses, Ruhr-University Bochum, Bochum, North Rhine-Westphalia, Germany
| | - Günter Gisselmann
- Department of Cell Physiology, Ruhr-University Bochum, Bochum, North Rhine-Westphalia, Germany
| | - Klemens F. Stoertkuhl
- AG Physiology of Senses, Ruhr-University Bochum, Bochum, North Rhine-Westphalia, Germany
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2
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Abstract
The present study aimed to systematically examine whether laurinal, orange odor, and a specifically designed "perfume" influence sleep quality. During sleep, healthy participants (n = 139) were presented with odor or no odor through nose clips for fourteen consecutive nights (phase one). We collected physiological parameters together with subjective reports. Later on, longer lasting effects of this manipulation were examined for the following fourteen nights (phase two) without exposition to odors. Additionally, olfactory, cognitive and non-cognitive measures were conducted before phase one, between both phases and after phase two. One-way analyses of variance for repeated measures with nights and condition (1 vs 2) as the within-subject factor and odor condition (0, 1, 2 or 3) together with odor pleasantness rating as between-subject factor, was employed to analyse data. Overall, the present results demonstrated that the odor condition in comparison to control had no consistent effect on sleep in healthy participants which can be possibly explained by exposure to odors via nose clips. However, the analyses indicated that the individual pleasantness of odors enhanced the positive assessment of sleep quality. Altogether, the present results indicate that the subjective perception of an odor's hedonic value appears to be crucial for sleep quality, not the odors themselves.
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3
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Belelli D, Hales TG, Lambert JJ, Luscher B, Olsen R, Peters JA, Rudolph U, Sieghart W. GABA A receptors in GtoPdb v.2021.3. IUPHAR/BPS GUIDE TO PHARMACOLOGY CITE 2021; 2021. [PMID: 35005623 DOI: 10.2218/gtopdb/f72/2021.3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
The GABAA receptor is a ligand-gated ion channel of the Cys-loop family that includes the nicotinic acetylcholine, 5-HT3 and strychnine-sensitive glycine receptors. GABAA receptor-mediated inhibition within the CNS occurs by fast synaptic transmission, sustained tonic inhibition and temporally intermediate events that have been termed 'GABAA, slow' [45]. GABAA receptors exist as pentamers of 4TM subunits that form an intrinsic anion selective channel. Sequences of six α, three β, three γ, one δ, three ρ, one ε, one π and one θ GABAA receptor subunits have been reported in mammals [278, 235, 236, 283]. The π-subunit is restricted to reproductive tissue. Alternatively spliced versions of many subunits exist (e.g. α4- and α6- (both not functional) α5-, β2-, β3- and γ2), along with RNA editing of the α3 subunit [71]. The three ρ-subunits, (ρ1-3) function as either homo- or hetero-oligomeric assemblies [359, 50]. Receptors formed from ρ-subunits, because of their distinctive pharmacology that includes insensitivity to bicuculline, benzodiazepines and barbiturates, have sometimes been termed GABAC receptors [359], but they are classified as GABA A receptors by NC-IUPHAR on the basis of structural and functional criteria [16, 235, 236]. Many GABAA receptor subtypes contain α-, β- and γ-subunits with the likely stoichiometry 2α.2β.1γ [168, 235]. It is thought that the majority of GABAA receptors harbour a single type of α- and β - subunit variant. The α1β2γ2 hetero-oligomer constitutes the largest population of GABAA receptors in the CNS, followed by the α2β3γ2 and α3β3γ2 isoforms. Receptors that incorporate the α4- α5-or α 6-subunit, or the β1-, γ1-, γ3-, δ-, ε- and θ-subunits, are less numerous, but they may nonetheless serve important functions. For example, extrasynaptically located receptors that contain α6- and δ-subunits in cerebellar granule cells, or an α4- and δ-subunit in dentate gyrus granule cells and thalamic neurones, mediate a tonic current that is important for neuronal excitability in response to ambient concentrations of GABA [209, 272, 83, 19, 288]. GABA binding occurs at the β+/α- subunit interface and the homologous γ+/α- subunits interface creates the benzodiazepine site. A second site for benzodiazepine binding has recently been postulated to occur at the α+/β- interface ([254]; reviewed by [282]). The particular α-and γ-subunit isoforms exhibit marked effects on recognition and/or efficacy at the benzodiazepine site. Thus, receptors incorporating either α4- or α6-subunits are not recognised by 'classical' benzodiazepines, such as flunitrazepam (but see [356]). The trafficking, cell surface expression, internalisation and function of GABAA receptors and their subunits are discussed in detail in several recent reviews [52, 140, 188, 316] but one point worthy of note is that receptors incorporating the γ2 subunit (except when associated with α5) cluster at the postsynaptic membrane (but may distribute dynamically between synaptic and extrasynaptic locations), whereas as those incorporating the δ subunit appear to be exclusively extrasynaptic. NC-IUPHAR [16, 235, 3, 2] class the GABAA receptors according to their subunit structure, pharmacology and receptor function. Currently, eleven native GABAA receptors are classed as conclusively identified (i.e., α1β2γ2, α1βγ2, α3βγ2, α4βγ2, α4β2δ, α4β3δ, α5βγ2, α6βγ2, α6β2δ, α6β3δ and ρ) with further receptor isoforms occurring with high probability, or only tentatively [235, 236]. It is beyond the scope of this Guide to discuss the pharmacology of individual GABAA receptor isoforms in detail; such information can be gleaned in the reviews [16, 95, 168, 173, 143, 278, 216, 235, 236] and [9, 10]. Agents that discriminate between α-subunit isoforms are noted in the table and additional agents that demonstrate selectivity between receptor isoforms, for example via β-subunit selectivity, are indicated in the text below. The distinctive agonist and antagonist pharmacology of ρ receptors is summarised in the table and additional aspects are reviewed in [359, 50, 145, 223]. Several high-resolution cryo-electron microscopy structures have been described in which the full-length human α1β3γ2L GABAA receptor in lipid nanodiscs is bound to the channel-blocker picrotoxin, the competitive antagonist bicuculline, the agonist GABA (γ-aminobutyric acid), and the classical benzodiazepines alprazolam and diazepam [198].
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4
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Lie MEK, Falk-Petersen CB, Piilgaard L, Griem-Krey N, Wellendorph P, Kornum BR. GABA A receptor β 1 -subunit knock-out mice show increased delta power in NREM sleep and decreased theta power in REM sleep. Eur J Neurosci 2021; 54:4445-4455. [PMID: 33942407 DOI: 10.1111/ejn.15267] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2020] [Revised: 04/23/2021] [Accepted: 04/28/2021] [Indexed: 11/28/2022]
Abstract
γ-Aminobutyric acid (GABA) acting through heteropentameric GABAA receptors plays a pivotal role in the sleep-promoting circuitry. Whereas the role of the different GABAA receptor α-subunits in sleep regulation and in mediating the effect of benzodiazepines for treatment of insomnia is well-described, the β-subunits are less studied. Here we report the first study characterizing sleep in mice lacking the GABAA receptor β1 -subunit (β1 -/- mice). We show that β1 -/- mice have a distinct and abnormal sleep phenotype characterized by increased delta power in non-rapid eye movement (NREM) sleep and decreased theta activity in rapid eye movement (REM) sleep compared to β1 +/+ mice, without any change in the overall sleep-wake architecture. From GABAA receptor-specific autoradiography, it is further demonstrated that functional β1 -subunit-containing GABAA receptors display the highest binding levels in the hippocampus and frontal cortex. In conclusion, this study suggests that the GABAA receptor β1 -subunit does not play an important role in sleep initiation or maintenance but instead regulates the power spectrum and especially the expression of theta rhythm. This provides new knowledge on the complex role of GABAA receptor subunits in sleep regulation. In addition, β1 -/- mice could provide a useful mouse model for future studies of the physiological role of delta and theta rhythms during sleep.
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Affiliation(s)
- Maria Elena Klibo Lie
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | | | - Louise Piilgaard
- Department of Neuroscience, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Nane Griem-Krey
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Petrine Wellendorph
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Birgitte Rahbek Kornum
- Department of Neuroscience, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
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5
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Gomila AMJ, Rustler K, Maleeva G, Nin-Hill A, Wutz D, Bautista-Barrufet A, Rovira X, Bosch M, Mukhametova E, Petukhova E, Ponomareva D, Mukhamedyarov M, Peiretti F, Alfonso-Prieto M, Rovira C, König B, Bregestovski P, Gorostiza P. Photocontrol of Endogenous Glycine Receptors In Vivo. Cell Chem Biol 2020; 27:1425-1433.e7. [PMID: 32846115 DOI: 10.1016/j.chembiol.2020.08.005] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2019] [Revised: 04/14/2020] [Accepted: 08/04/2020] [Indexed: 12/15/2022]
Abstract
Glycine receptors (GlyRs) are indispensable for maintaining excitatory/inhibitory balance in neuronal circuits that control reflexes and rhythmic motor behaviors. Here we have developed Glyght, a GlyR ligand controlled with light. It is selective over other Cys-loop receptors, is active in vivo, and displays an allosteric mechanism of action. The photomanipulation of glycinergic neurotransmission opens new avenues to understanding inhibitory circuits in intact animals and to developing drug-based phototherapies.
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Affiliation(s)
- Alexandre M J Gomila
- Institute for Bioengineering of Catalonia (IBEC), The Barcelona Institute of Science and Technology (BIST), Barcelona 08028, Spain
| | - Karin Rustler
- University of Regensburg, Institute of Organic Chemistry, Regensburg 93053, Germany
| | - Galyna Maleeva
- Institute for Bioengineering of Catalonia (IBEC), The Barcelona Institute of Science and Technology (BIST), Barcelona 08028, Spain; Aix-Marseille Université, INSERM, INS, Institut de Neurosciences des Systèmes, Marseille 13005, France
| | - Alba Nin-Hill
- University of Barcelona, Department of Inorganic and Organic Chemistry, Institute of Theoretical Chemistry (IQTCUB), Barcelona 08028, Spain
| | - Daniel Wutz
- University of Regensburg, Institute of Organic Chemistry, Regensburg 93053, Germany
| | - Antoni Bautista-Barrufet
- Institute for Bioengineering of Catalonia (IBEC), The Barcelona Institute of Science and Technology (BIST), Barcelona 08028, Spain
| | - Xavier Rovira
- Institute for Bioengineering of Catalonia (IBEC), The Barcelona Institute of Science and Technology (BIST), Barcelona 08028, Spain
| | - Miquel Bosch
- Institute for Bioengineering of Catalonia (IBEC), The Barcelona Institute of Science and Technology (BIST), Barcelona 08028, Spain
| | - Elvira Mukhametova
- Aix-Marseille Université, INSERM, INS, Institut de Neurosciences des Systèmes, Marseille 13005, France; Kazan Federal University, Open Lab of Motor Neurorehabilitation, Kazan, Russia
| | - Elena Petukhova
- Institute of Neurosciences, Kazan State Medical University, Kazan, Russia
| | - Daria Ponomareva
- Institute of Neurosciences, Kazan State Medical University, Kazan, Russia
| | | | - Franck Peiretti
- Aix Marseille Université, INSERM 1263, INRA 1260, C2VN, Marseille, France
| | - Mercedes Alfonso-Prieto
- Institute for Advanced Simulation IAS-5 and Institute of Neuroscience and Medicine INM-9, Computational Biomedicine, Forschungszentrum Jülich, 52425 Jülich, Germany; Cécile and Oskar Vogt Institute for Brain Research, Medical Faculty, Heinrich Heine University Düsseldorf, 40225 Düsseldorf, Germany
| | - Carme Rovira
- University of Barcelona, Department of Inorganic and Organic Chemistry, Institute of Theoretical Chemistry (IQTCUB), Barcelona 08028, Spain; Catalan Institution for Research and Advanced Studies (ICREA), Barcelona 08003 Spain.
| | - Burkhard König
- University of Regensburg, Institute of Organic Chemistry, Regensburg 93053, Germany.
| | - Piotr Bregestovski
- Aix-Marseille Université, INSERM, INS, Institut de Neurosciences des Systèmes, Marseille 13005, France; Institute of Neurosciences, Kazan State Medical University, Kazan, Russia.
| | - Pau Gorostiza
- Institute for Bioengineering of Catalonia (IBEC), The Barcelona Institute of Science and Technology (BIST), Barcelona 08028, Spain; Catalan Institution for Research and Advanced Studies (ICREA), Barcelona 08003 Spain; CIBER-BBN, Madrid 28001 Spain.
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6
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Gisselmann G, Alisch D, Welbers-Joop B, Hatt H. Effects of Quinine, Quinidine and Chloroquine on Human Muscle Nicotinic Acetylcholine Receptors. Front Pharmacol 2018; 9:1339. [PMID: 30515099 PMCID: PMC6255974 DOI: 10.3389/fphar.2018.01339] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2018] [Accepted: 10/30/2018] [Indexed: 11/24/2022] Open
Abstract
The genus Cinchona is known for a range of alkaloids, such as quinine, quinidine, cinchonine, and cinchonidine. Cinchona bark has been used as an antimalarial agent for more than 400 years. Quinine was first isolated in 1820 and is still acknowledged in the therapy of chloroquine-resistant falciparum malaria; in lower dosage quinine has been used as treatment for leg cramps since the 1940s. Here we report the effects of the quinoline derivatives quinine, quinidine, and chloroquine on human adult and fetal muscle nicotinic acetylcholine receptors (nAChRs). It could be demonstrated that the compounds blocked acetylcholine (ACh)-evoked responses in Xenopus laevis oocytes expressing the adult nAChR composed of αβ𝜀δ subunits in a concentration-dependent manner, with a ranked potency of quinine (IC50 = 1.70 μM), chloroquine (IC50 = 2.22 μM) and quinidine (IC50 = 3.96 μM). At the fetal nAChR composed of αβγδ subunits, the IC50 for quinine was found to be 2.30 μM. The efficacy of the block by quinine was independent of the ACh concentration. Therefore, quinine is proposed to inhibit ACh-evoked currents in a non-competitive manner. The present results add to the pharmacological characterization of muscle nAChRs and indicate that quinine is effective at the muscular nAChRs close to therapeutic blood concentrations required for the therapy and prophylaxis of nocturnal leg cramps, suggesting that the clinically proven efficacy of quinine could be based on targeting nAChRs.
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Affiliation(s)
- Günter Gisselmann
- Department of Cell Physiology, Ruhr-University-Bochum, Bochum, Germany
| | - Desiree Alisch
- Department of Cell Physiology, Ruhr-University-Bochum, Bochum, Germany
| | | | - Hanns Hatt
- Department of Cell Physiology, Ruhr-University-Bochum, Bochum, Germany
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7
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Sieghart W, Savić MM. International Union of Basic and Clinical Pharmacology. CVI: GABAA Receptor Subtype- and Function-selective Ligands: Key Issues in Translation to Humans. Pharmacol Rev 2018; 70:836-878. [DOI: 10.1124/pr.117.014449] [Citation(s) in RCA: 105] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
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8
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Li Z, Cogswell M, Hixson K, Brooks-Kayal AR, Russek SJ. Nuclear Respiratory Factor 1 (NRF-1) Controls the Activity Dependent Transcription of the GABA-A Receptor Beta 1 Subunit Gene in Neurons. Front Mol Neurosci 2018; 11:285. [PMID: 30186109 PMCID: PMC6113564 DOI: 10.3389/fnmol.2018.00285] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2018] [Accepted: 07/27/2018] [Indexed: 11/13/2022] Open
Abstract
While the exact role of β1 subunit-containing GABA-A receptors (GABARs) in brain function is not well understood, altered expression of the β1 subunit gene (GABRB1) is associated with neurological and neuropsychiatric disorders. In particular, down-regulation of β1 subunit levels is observed in brains of patients with epilepsy, autism, bipolar disorder and schizophrenia. A pathophysiological feature of these disease states is imbalance in energy metabolism and mitochondrial dysfunction. The transcription factor, nuclear respiratory factor 1 (NRF-1), has been shown to be a key mediator of genes involved in oxidative phosphorylation and mitochondrial biogenesis. Using a variety of molecular approaches (including mobility shift, promoter/reporter assays, and overexpression of dominant negative NRF-1), we now report that NRF-1 regulates transcription of GABRB1 and that its core promoter contains a conserved canonical NRF-1 element responsible for sequence specific binding and transcriptional activation. Our identification of GABRB1 as a new target for NRF-1 in neurons suggests that genes coding for inhibitory neurotransmission may be coupled to cellular metabolism. This is especially meaningful as binding of NRF-1 to its element is sensitive to the kind of epigenetic changes that occur in multiple disorders associated with altered brain inhibition.
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Affiliation(s)
- Zhuting Li
- Laboratory of Translational Epilepsy, Department of Pharmacology and Experimental Therapeutics, School of Medicine, Boston University, Boston, MA, United States.,Department of Biomedical Engineering, College of Engineering, Boston University, Boston, MA, United States
| | - Meaghan Cogswell
- Laboratory of Translational Epilepsy, Department of Pharmacology and Experimental Therapeutics, School of Medicine, Boston University, Boston, MA, United States
| | - Kathryn Hixson
- Laboratory of Translational Epilepsy, Department of Pharmacology and Experimental Therapeutics, School of Medicine, Boston University, Boston, MA, United States
| | - Amy R Brooks-Kayal
- Department of Pediatrics, Division of Neurology, School of Medicine, University of Colorado, Aurora, CO, United States.,Department of Pharmaceutical Sciences, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of Colorado Anschutz Medical Campus, Aurora, CO, United States
| | - Shelley J Russek
- Laboratory of Translational Epilepsy, Department of Pharmacology and Experimental Therapeutics, School of Medicine, Boston University, Boston, MA, United States.,Department of Biology, Boston University, Boston, MA, United States
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9
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Naiman R. Insomnia. Integr Med (Encinitas) 2018. [DOI: 10.1016/b978-0-323-35868-2.00009-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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10
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Molecular tools for GABA A receptors: High affinity ligands for β1-containing subtypes. Sci Rep 2017; 7:5674. [PMID: 28720884 PMCID: PMC5516028 DOI: 10.1038/s41598-017-05757-4] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2016] [Accepted: 06/05/2017] [Indexed: 12/15/2022] Open
Abstract
γ-Aminobutyric acid type A (GABAA) receptors are pentameric GABA-gated chloride channels that are, in mammalians, drawn from a repertoire of 19 different genes, namely α1-6, β1-3, γ1-3, δ, ε, θ, π and ρ1-3. The existence of this wide variety of subunits as well as their diverse assembly into different subunit compositions result in miscellaneous receptor subtypes. In combination with the large number of known and putative allosteric binding sites, this leads to a highly complex pharmacology. Recently, a novel binding site at extracellular α+/β- interfaces was described as the site of modulatory action of several pyrazoloquinolinones. In this study we report a highly potent ligand from this class of compounds with pronounced β1-selectivity that mainly lacks α-subunit selectivity. It constitutes the most potent β1-selective positive allosteric modulatory ligand with known binding site. In addition, a proof of concept pyrazoloquinolinone ligand lacking the additional high affinity interaction with the benzodiazepine binding site is presented. Ultimately, such ligands can be used as invaluable molecular tools for the detection of β1-containing receptor subtypes and the investigation of their abundance and distribution.
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11
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Hoffmann KM, Herbrechter R, Ziemba PM, Lepke P, Beltrán L, Hatt H, Werner M, Gisselmann G. Kampo Medicine: Evaluation of the Pharmacological Activity of 121 Herbal Drugs on GABAA and 5-HT3A Receptors. Front Pharmacol 2016; 7:219. [PMID: 27524967 PMCID: PMC4965468 DOI: 10.3389/fphar.2016.00219] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2016] [Accepted: 07/06/2016] [Indexed: 12/24/2022] Open
Abstract
Kampo medicine is a form of Japanese phytotherapy originating from traditional Chinese medicine (TCM). During the last several decades, much attention has been paid to the pharmacological effects of these medical plants and their constituents. However, in many cases, a systematic screening of Kampo remedies to determine pharmacologically relevant targets is still lacking. In this study, a broad screening of Kampo remedies was performed to look for pharmacologically relevant 5-HT3A and GABAA receptor ligands. Several of the Kampo remedies are currently used for symptoms such as nausea, emesis, gastrointestinal motility disorders, anxiety, restlessness, or insomnia. Therefore, the pharmacological effects of 121 herbal drugs from Kampo medicine were analyzed as ethanol tinctures on heterologously expressed 5-HT3A and GABAA receptors, due to the involvement of these receptors in such pathophysiological processes. The tinctures of Lindera aggregata (radix) and Leonurus japonicus (herba) were the most effective inhibitory compounds on the 5-HT3A receptor. Further investigation of known ingredients in these compounds led to the identification of leonurine from Leonurus as a new natural 5-HT3A receptor antagonist. Several potentiating herbs (e.g., Magnolia officinalis (cortex), Syzygium aromaticum (flos), and Panax ginseng (radix)) were also identified for the GABAA receptor, which are all traditionally used for their sedative or anxiolytic effects. A variety of tinctures with antagonistic effects Salvia miltiorrhiza (radix) were also detected. Therefore, this study reveals new insights into the pharmacological action of a broad spectrum of herbal drugs from Kampo, allowing for a better understanding of their physiological effects and clinical applications.
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Affiliation(s)
- Katrin M Hoffmann
- Department of Cell Physiology, Ruhr University Bochum Bochum, Germany
| | - Robin Herbrechter
- Department of Cell Physiology, Ruhr University Bochum Bochum, Germany
| | - Paul M Ziemba
- Department of Cell Physiology, Ruhr University Bochum Bochum, Germany
| | - Peter Lepke
- Kronen Apotheke Wuppertal Wuppertal, Germany
| | - Leopoldo Beltrán
- Department of Cell Physiology, Ruhr University Bochum Bochum, Germany
| | - Hanns Hatt
- Department of Cell Physiology, Ruhr University Bochum Bochum, Germany
| | - Markus Werner
- Department of Cell Physiology, Ruhr University Bochum Bochum, Germany
| | - Günter Gisselmann
- Department of Cell Physiology, Ruhr University Bochum Bochum, Germany
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12
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Hoffmann KM, Beltrán L, Ziemba PM, Hatt H, Gisselmann G. Potentiating effect of glabridin from Glycyrrhiza glabra on GABA A receptors. Biochem Biophys Rep 2016; 6:197-202. [PMID: 29214227 PMCID: PMC5689168 DOI: 10.1016/j.bbrep.2016.04.007] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2015] [Revised: 04/07/2016] [Accepted: 04/14/2016] [Indexed: 10/25/2022] Open
Abstract
Extracts from Glycyrrhiza are traditionally used for the treatment of insomnia and anxiety. Glabridin is one of the main flavonoid compounds from Glycyrrhiza glabra and displays a broad range of biological properties. In the present work, we investigated the effect of glabridin on GABAA receptors. For this purpose, we employed the two-electrode voltage-clamp technique on Xenopus laevis oocytes expressing recombinant GABAA receptors. Through this approach, we observed that glabridin presents a strong potentiating effect on GABAA α1β(1-3)γ2 receptors. The potentiation was slightly dependent on the β subunit and was most pronounced at the α1β2γ2 subunit combination, which forms the most abundant GABAA receptor in the CNS. Glabridin potentiated with an EC50 of 6.3±1.7 µM and decreased the EC50 of the receptor for GABA by approximately 12-fold. The potentiating effect of glabridin is flumazenil-insensitive and does not require the benzodiazepine binding site. Glabridin acts on the β subunit of GABAA receptors by a mechanism involving the M286 residue, which is a key amino acid at the binding site for general anesthetics, such as propofol and etomidate. Our results demonstrate that GABAA receptors are strongly potentiated by one of the main flavonoid compounds from Glycyrrhiza glabra and suggest that glabridin could contribute to the reported hypnotic effect of Glycyrrhiza extracts.
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Affiliation(s)
- Katrin M Hoffmann
- Ruhr-University Bochum, Department of Cell Physiology, Bochum, Germany
| | - Leopoldo Beltrán
- Ruhr-University Bochum, Department of Cell Physiology, Bochum, Germany
| | - Paul M Ziemba
- Ruhr-University Bochum, Department of Cell Physiology, Bochum, Germany
| | - Hanns Hatt
- Ruhr-University Bochum, Department of Cell Physiology, Bochum, Germany
| | - Günter Gisselmann
- Ruhr-University Bochum, Department of Cell Physiology, Bochum, Germany
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13
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Activation and modulation of recombinantly expressed serotonin receptor type 3A by terpenes and pungent substances. Biochem Biophys Res Commun 2015; 467:1090-6. [DOI: 10.1016/j.bbrc.2015.09.074] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2015] [Accepted: 09/12/2015] [Indexed: 11/22/2022]
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Thiel U, Platt SJ, Wolf S, Hatt H, Gisselmann G. Identification of amino acids involved in histamine potentiation of GABA A receptors. Front Pharmacol 2015; 6:106. [PMID: 26074818 PMCID: PMC4443022 DOI: 10.3389/fphar.2015.00106] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2015] [Accepted: 05/01/2015] [Indexed: 12/13/2022] Open
Abstract
Histamine is a neurotransmitter involved in a number of physiological and neuronal functions. In mammals, such as humans, and rodents, the histaminergic neurons found in the tuberomamillary nucleus project widely throughout the central nervous system. Histamine acts as positive modulator of GABAA receptors (GABAARs) and, in high concentrations (10 mM), as negative modulator of the strychnine-sensitive glycine receptor. However, the exact molecular mechanisms by which histamine acts on GABAARs are unknown. In our study, we aimed to identify amino acids potentially involved in the modulatory effect of histamine on GABAARs. We expressed GABAARs with 12 different point mutations in Xenopus laevis oocytes and characterized the effect of histamine on GABA-induced currents using the two-electrode voltage clamp technique. Our data demonstrate that the amino acid residues β2(N265) and β2(M286), which are important for modulation by propofol, are not involved in the action of histamine. However, we found that histamine modulation is dependent on the amino acid residues α1(R120), β2(Y157), β2(D163), β3(V175), and β3(Q185). We showed that the amino acid residues β2(Y157) and β3(Q185) mediate the positive modulatory effect of histamine on GABA-induced currents, whereas α1(R120) and β2(D163) form a potential histamine interaction site in GABAARs.
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Affiliation(s)
- Ulrike Thiel
- Department of Cell Physiology, Ruhr University Bochum Bochum, Germany
| | - Sarah J Platt
- Department of Cell Physiology, Ruhr University Bochum Bochum, Germany
| | - Steffen Wolf
- Department of Biophysics, Ruhr University Bochum Bochum, Germany ; Department of Biophysics, Key Laboratory of Computational Biology, CAS-MPG Partner Institute for Computational Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences Shanghai, China
| | - Hanns Hatt
- Department of Cell Physiology, Ruhr University Bochum Bochum, Germany
| | - Günter Gisselmann
- Department of Cell Physiology, Ruhr University Bochum Bochum, Germany
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15
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Villumsen IS, Wellendorph P, Smart TG. Pharmacological characterisation of murine α4β1δ GABAA receptors expressed in Xenopus oocytes. BMC Neurosci 2015; 16:8. [PMID: 25887256 PMCID: PMC4359537 DOI: 10.1186/s12868-015-0148-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2014] [Accepted: 02/20/2015] [Indexed: 11/15/2022] Open
Abstract
Background GABAA receptor subunit composition has a profound effect on the receptor’s physiological and pharmacological properties. The receptor β subunit is widely recognised for its importance in receptor assembly, trafficking and post-translational modifications, but its influence on extrasynaptic GABAA receptor function is less well understood. Here, we examine the pharmacological properties of a potentially native extrasynaptic GABAA receptor that incorporates the β1 subunit, specifically composed of α4β1δ and α4β1 subunits. Results GABA activated concentration-dependent responses at α4β1δ and α4β1 receptors with EC50 values in the nanomolar to micromolar range, respectively. The divalent cations Zn2+ and Cu2+, and the β1-selective inhibitor salicylidine salicylhydrazide (SCS), inhibited GABA-activated currents at α4β1δ receptors. Surprisingly the α4β1 receptor demonstrated biphasic sensitivity to Zn2+ inhibition that may reflect variable subunit stoichiometries with differing sensitivity to Zn2+. The neurosteroid tetrahydro-deoxycorticosterone (THDOC) significantly increased GABA-initiated responses in concentrations above 30 nM for α4β1δ receptors. Conclusions With this study we report the first pharmacological characterisation of various GABAA receptor ligands acting at murine α4β1δ GABAA receptors, thereby improving our understanding of the molecular pharmacology of this receptor isoform. This study highlights some notable differences in the pharmacology of murine and human α4β1δ receptors. We consider the likelihood that the α4β1δ receptor may play a role as an extrasynaptic GABAA receptor in the nervous system.
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Affiliation(s)
- Inge S Villumsen
- Department of Neuroscience, Physiology & Pharmacology, University College London, Gower Street, London, WC1E 6BT, UK. .,Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Fruebjergvej 3, 2100, Copenhagen, Denmark.
| | - Petrine Wellendorph
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Fruebjergvej 3, 2100, Copenhagen, Denmark.
| | - Trevor G Smart
- Department of Neuroscience, Physiology & Pharmacology, University College London, Gower Street, London, WC1E 6BT, UK.
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16
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Alexander SPH, Benson HE, Faccenda E, Pawson AJ, Sharman JL, Spedding M, Peters JA, Harmar AJ. The Concise Guide to PHARMACOLOGY 2013/14: ligand-gated ion channels. Br J Pharmacol 2014; 170:1582-606. [PMID: 24528238 PMCID: PMC3892288 DOI: 10.1111/bph.12446] [Citation(s) in RCA: 113] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
The Concise Guide to PHARMACOLOGY 2013/14 provides concise overviews of the key properties of over 2000 human drug targets with their pharmacology, plus links to an open access knowledgebase of drug targets and their ligands (www.guidetopharmacology.org), which provides more detailed views of target and ligand properties. The full contents can be found at http://onlinelibrary.wiley.com/doi/10.1111/bph.12444/full. Ligand-gated ion channels are one of the seven major pharmacological targets into which the Guide is divided, with the others being G protein-coupled receptors, ion channels, catalytic receptors, nuclear hormone receptors, transporters and enzymes. These are presented with nomenclature guidance and summary information on the best available pharmacological tools, alongside key references and suggestions for further reading. A new landscape format has easy to use tables comparing related targets. It is a condensed version of material contemporary to late 2013, which is presented in greater detail and constantly updated on the website www.guidetopharmacology.org, superseding data presented in previous Guides to Receptors and Channels. It is produced in conjunction with NC-IUPHAR and provides the official IUPHAR classification and nomenclature for human drug targets, where appropriate. It consolidates information previously curated and displayed separately in IUPHAR-DB and the Guide to Receptors and Channels, providing a permanent, citable, point-in-time record that will survive database updates.
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Affiliation(s)
- Stephen P H Alexander
- School of Life Sciences, University of Nottingham Medical School, Nottingham, NG7 2UH, UK
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17
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May AC, Fleischer W, Kletke O, Haas HL, Sergeeva OA. Benzodiazepine-site pharmacology on GABAA receptors in histaminergic neurons. Br J Pharmacol 2014; 170:222-32. [PMID: 23799902 DOI: 10.1111/bph.12280] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2012] [Revised: 06/13/2013] [Accepted: 06/18/2013] [Indexed: 01/04/2023] Open
Abstract
BACKGROUND AND PURPOSE The histaminergic tuberomamillary nucleus (TMN) of the posterior hypothalamus controls the cognitive aspects of vigilance which is reduced by common sedatives and anxiolytics. The receptors targeted by these drugs in histaminergic neurons are unknown. TMN neurons express nine different subunits of the GABAA receptor (GABAA R) with three α- (α1, α2 and α5) and two γ- (γ1, γ 2) subunits, which confer different pharmacologies of the benzodiazepine-binding site. EXPERIMENTAL APPROACH We investigated the actions of zolpidem, midazolam, diazepam, chlordiazepoxide, flumazenil (Ro15-1788) and methyl-6,7-dimethoxy-4-ethyl-β-carboline-3-carboxylate (DMCM) in TMN neurons using mouse genetics, electrophysiological and molecular biological methods. KEY RESULTS We find the sensitivity of GABAA R to zolpidem, midazolam and DMCM significantly reduced in TMN neurons from γ2F77I mice, but modulatory activities of diazepam, chlordiazepoxide and flumazenil not affected. Potencies and efficacies of these compounds are in line with the dominance of α2- and α1-subunit containing receptors associated with γ2- or γ1-subunits. Functional expression of the γ1-subunit is supported by siRNA-based knock-down experiments in γ2F77I mice. CONCLUSIONS AND IMPLICATIONS GABAA R of TMN neurons respond to a variety of common sedatives with a high affinity binding site (γ2F77I) involved. The γ1-subunit likely contributes to the action of common sedatives in TMN neurons. This study is relevant for understanding the role of neuronal histamine and benzodiazepines in disorders of sleep and metabolism.
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Affiliation(s)
- A C May
- Department of Neurophysiology, Medical Faculty, Heinrich-Heine-Universität, Düsseldorf, Germany
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18
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GHB receptor targets in the CNS: Focus on high-affinity binding sites. Biochem Pharmacol 2014; 87:220-8. [DOI: 10.1016/j.bcp.2013.10.028] [Citation(s) in RCA: 78] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2013] [Revised: 10/29/2013] [Accepted: 10/29/2013] [Indexed: 12/13/2022]
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Kessler A, Sahin-Nadeem H, Lummis SCR, Weigel I, Pischetsrieder M, Buettner A, Villmann C. GABA(A) receptor modulation by terpenoids from Sideritis extracts. Mol Nutr Food Res 2013; 58:851-62. [PMID: 24273211 PMCID: PMC4384808 DOI: 10.1002/mnfr.201300420] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2013] [Revised: 09/12/2013] [Accepted: 09/15/2013] [Indexed: 11/10/2022]
Abstract
SCOPE GABAA receptors are modulated by Sideritis extracts. The aim of this study was to identify single substances from Sideritis extracts responsible for GABAA receptor modulation. METHODS AND RESULTS Single volatile substances identified by GC have been tested in two expression systems, Xenopus oocytes and human embryonic kidney cells. Some of these substances, especially carvacrol, were highly potent on GABAA receptors composed of α1β2 and α1β2γ2 subunits. All effects measured were independent from the presence of the γ2 subunit. As Sideritis extracts contain a high amount of terpenes, 13 terpenes with similar structure elements were tested in the same way. Following a prescreening on α1β2 GABAA receptors, a high-throughput method was used for identification of the most effective terpenoid substances on GABA-affinity of α1β2γ2 receptors expressed in transfected cell lines. Isopulegol, pinocarveol, verbenol, and myrtenol were the most potent modifiers of GABAA receptor function. CONCLUSION Comparing the chemical structures, the action of terpenes on GABAA receptors is most probably due to the presence of hydroxyl groups and a bicyclic character of the substances tested. We propose an allosteric modulation independent from the γ2 subunit and similar to the action of alcohols and anesthetics.
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Affiliation(s)
- Artur Kessler
- Department of Chemistry and Pharmacy, Food Chemistry Division, University of Erlangen-Nuernberg, Erlangen, Germany
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20
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Lübbert M, Kyereme J, Schöbel N, Beltrán L, Wetzel CH, Hatt H. Transient receptor potential channels encode volatile chemicals sensed by rat trigeminal ganglion neurons. PLoS One 2013; 8:e77998. [PMID: 24205061 PMCID: PMC3804614 DOI: 10.1371/journal.pone.0077998] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2013] [Accepted: 09/08/2013] [Indexed: 12/11/2022] Open
Abstract
Primary sensory afferents of the dorsal root and trigeminal ganglia constantly transmit sensory information depicting the individual’s physical and chemical environment to higher brain regions. Beyond the typical trigeminal stimuli (e.g. irritants), environmental stimuli comprise a plethora of volatile chemicals with olfactory components (odorants). In spite of a complete loss of their sense of smell, anosmic patients may retain the ability to roughly discriminate between different volatile compounds. While the detailed mechanisms remain elusive, sensory structures belonging to the trigeminal system seem to be responsible for this phenomenon. In order to gain a better understanding of the mechanisms underlying the activation of the trigeminal system by volatile chemicals, we investigated odorant-induced membrane potential changes in cultured rat trigeminal neurons induced by the odorants vanillin, heliotropyl acetone, helional, and geraniol. We observed the dose-dependent depolarization of trigeminal neurons upon application of these substances occurring in a stimulus-specific manner and could show that distinct neuronal populations respond to different odorants. Using specific antagonists, we found evidence that TRPA1, TRPM8, and/or TRPV1 contribute to the activation. In order to further test this hypothesis, we used recombinantly expressed rat and human variants of these channels to investigate whether they are indeed activated by the odorants tested. We additionally found that the odorants dose-dependently inhibit two-pore potassium channels TASK1 and TASK3 heterologously expressed In Xenopus laevis oocytes. We suggest that the capability of various odorants to activate different TRP channels and to inhibit potassium channels causes neuronal depolarization and activation of distinct subpopulations of trigeminal sensory neurons, forming the basis for a specific representation of volatile chemicals in the trigeminal ganglia.
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Affiliation(s)
- Matthias Lübbert
- Department of Cell Physiology, Ruhr University Bochum, Bochum, Germany
- * E-mail:
| | - Jessica Kyereme
- Department of Cell Physiology, Ruhr University Bochum, Bochum, Germany
| | - Nicole Schöbel
- Leibniz Research Centre for Working Environment and Human Factors, University of Dortmund, Dortmund, Germany
| | - Leopoldo Beltrán
- Department of Cell Physiology, Ruhr University Bochum, Bochum, Germany
| | - Christian Horst Wetzel
- Department of Psychiatry and Psychotherapy, University of Regensburg, Regensburg, Germany
| | - Hanns Hatt
- Department of Cell Physiology, Ruhr University Bochum, Bochum, Germany
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Kletke O, Gisselmann G, May A, Hatt H, A. Sergeeva O. Partial agonism of taurine at gamma-containing native and recombinant GABAA receptors. PLoS One 2013; 8:e61733. [PMID: 23637894 PMCID: PMC3640040 DOI: 10.1371/journal.pone.0061733] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2012] [Accepted: 03/13/2013] [Indexed: 11/18/2022] Open
Abstract
Taurine is a semi-essential sulfonic acid found at high concentrations in plasma and mammalian tissues which regulates osmolarity, ion channel activity and glucose homeostasis. The structural requirements of GABAA-receptors (GABAAR) gated by taurine are not yet known. We determined taurine potency and efficacy relative to GABA at different types of recombinant GABAAR occurring in central histaminergic neurons of the mouse hypothalamic tuberomamillary nucleus (TMN) which controls arousal. At binary α1/2β1/3 receptors taurine was as efficient as GABA, whereas incorporation of the γ1/2 subunit reduced taurine efficacy to 60–90% of GABA. The mutation γ2F77I, which abolishes zolpidem potentiation, significantly reduced taurine efficacy at recombinant and native receptors compared to the wild type controls. As taurine was a full- or super- agonist at recombinant αxβ1δ-GABAAR, we generated a chimeric γ2 subunit carrying the δ subunit motif around F77 (MTVFLH). At α1/2β1γ2(MTVFLH) receptors taurine became a super-agonist, similar to δ-containing ternary receptors, but remained a partial agonist at β3-containing receptors. In conclusion, using site-directed mutagenesis we found structural determinants of taurine’s partial agonism at γ-containing GABAA receptors. Our study sheds new light on the β1 subunit conferring the widest range of taurine-efficacies modifying GABAAR function under (patho)physiological conditions.
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Affiliation(s)
- Olaf Kletke
- Department of Cell Physiology of the Ruhr-University, Bochum, Germany
- Department of Neurophysiology, Medical Faculty of Heinrich-Heine University, Düsseldorf, Germany
| | | | - Andrea May
- Department of Neurophysiology, Medical Faculty of Heinrich-Heine University, Düsseldorf, Germany
| | - Hanns Hatt
- Department of Cell Physiology of the Ruhr-University, Bochum, Germany
| | - Olga A. Sergeeva
- Department of Neurophysiology, Medical Faculty of Heinrich-Heine University, Düsseldorf, Germany
- * E-mail:
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22
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New insights in endogenous modulation of ligand-gated ion channels: histamine is an inverse agonist at strychnine sensitive glycine receptors. Eur J Pharmacol 2013; 710:59-66. [PMID: 23603522 DOI: 10.1016/j.ejphar.2013.04.002] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2012] [Revised: 03/28/2013] [Accepted: 04/03/2013] [Indexed: 01/18/2023]
Abstract
Histamine is involved in many physiological functions in the periphery and is an important neurotransmitter in the brain. It acts on metabotropic H1-H4 receptors mediating vasodilatation, bronchoconstriction and stimulation of gastric acid secretion. In the brain histamine is produced by neurons in the tuberomamillary nucleus (TMN), which controls arousal. Histamine is also a positive modulator of the inhibitory Cys-loop ligand-gated ion channel GABAA. We investigated now its effect on the second member of inhibitory Cys-loop ligand-gated ion channels, the strychnine sensitive glycine receptor. We expressed different human and rat glycine receptor subunits in Xenopus laevis oocytes and characterized the effect of histamine using the two electrode voltage clamp technique. Furthermore we investigated native glycine receptors in hypothalamic neurons using the patch-clamp technique. Histamine inhibited α1β glycine receptors with an IC50 of 5.2±0.3 mM. In presence of 10 mM histamine the glycine dose-response curve was shifted, increasing the EC50 for glycine from 25.5±1.4 μM to 42.4±2.3 μM. In addition, histamine blocked the spontaneous activity of RNA-edited α3β glycine receptors. Histamine inhibited glycine receptors expressed in hypothalamic TMN neurons with an IC50 of 4.6±0.3 mM. Our results give strong evidence that histamine is acting on the same binding site as glycine, being an inverse agonist that competitively antagonizes glycine receptors. Thus, we revealed histamine as an endogenous modulator of glycine receptors.
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Sieghart W. Anxioselective anxiolytics: additional perspective. Trends Pharmacol Sci 2013; 34:145-6. [PMID: 23394682 DOI: 10.1016/j.tips.2013.01.005] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2013] [Accepted: 01/14/2013] [Indexed: 10/27/2022]
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GABAergic inhibition of histaminergic neurons regulates active waking but not the sleep-wake switch or propofol-induced loss of consciousness. J Neurosci 2012; 32:13062-75. [PMID: 22993424 DOI: 10.1523/jneurosci.2931-12.2012] [Citation(s) in RCA: 79] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
The activity of histaminergic neurons in the tuberomammillary nucleus (TMN) of the hypothalamus correlates with an animal's behavioral state and maintains arousal. We examined how GABAergic inputs onto histaminergic neurons regulate this behavior. A prominent hypothesis, the "flip-flop" model, predicts that increased and sustained GABAergic drive onto these cells promotes sleep. Similarly, because of the histaminergic neurons' key hub-like place in the arousal circuitry, it has also been suggested that anesthetics such as propofol induce loss of consciousness by acting primarily at histaminergic neurons. We tested both these hypotheses in mice by genetically removing ionotropic GABA(A) or metabotropic GABA(B) receptors from histidine decarboxylase-expressing neurons. At the cellular level, histaminergic neurons deficient in synaptic GABA(A) receptors were significantly more excitable and were insensitive to the anesthetic propofol. At the behavioral level, EEG profiles were recorded in nontethered mice over 24 h. Surprisingly, GABAergic transmission onto histaminergic neurons had no effect in regulating the natural sleep-wake cycle and, in the case of GABA(A) receptors, for propofol-induced loss of righting reflex. The latter finding makes it unlikely that the histaminergic TMN has a central role in anesthesia. GABA(B) receptors on histaminergic neurons were dispensable for all behaviors examined. Synaptic inhibition of histaminergic cells by GABA(A) receptors, however, was essential for habituation to a novel environment.
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Kelley MH, Ortiz J, Shimizu K, Grewal H, Quillinan N, Herson PS. Alterations in Purkinje cell GABAA receptor pharmacology following oxygen and glucose deprivation and cerebral ischemia reveal novel contribution of β1 -subunit-containing receptors. Eur J Neurosci 2012; 37:555-63. [PMID: 23176253 DOI: 10.1111/ejn.12064] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2012] [Revised: 10/23/2012] [Accepted: 10/25/2012] [Indexed: 11/26/2022]
Abstract
Cerebellar Purkinje cells (PCs) are particularly sensitive to cerebral ischemia, and decreased GABA(A) receptor function following injury is thought to contribute to PC sensitivity to ischemia-induced excitotoxicity. Here we examined the functional properties of the GABA(A) receptors that are spared following ischemia in cultured Purkinje cells from rat and in vivo ischemia in mouse. Using subunit-specific positive modulators of GABA(A) receptors, we observed that oxygen and glucose deprivation (OGD) and cardiac arrest-induced cerebral ischemia cause a decrease in sensitivity to the β(2/3) -subunit-preferring compound, etomidate. However, sensitivity to propofol, a β-subunit-acting compound that modulates β(1-3) -subunits, was not affected by OGD. The α/γ-subunit-acting compounds, diazepam and zolpidem, were also unaffected by OGD. We performed single-cell reverse transcription-polymerase chain reaction on isolated PCs from acutely dissociated cerebellar tissue and observed that PCs expressed the β(1) -subunit, contrary to previous reports examining GABA(A) receptor subunit expression in PCs. GABA(A) receptor β(1) -subunit protein was also detected in cultured PCs by western blot and by immunohistochemistry in the adult mouse cerebellum and levels remained unaffected by ischemia. High concentrations of loreclezole (30 μm) inhibited PC GABA-mediated currents, as previously demonstrated with β(1) -subunit-containing GABA(A) receptors expressed in heterologous systems. From our data we conclude that PCs express the β(1) -subunit and that there is a greater contribution of β(1) -subunit-containing GABA(A) receptors following OGD.
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Affiliation(s)
- Melissa H Kelley
- Department of Anesthesiology and Perioperative Medicine, Oregon Health and Science University, Portland, OR, USA
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Sieghart W, Ramerstorfer J, Sarto-Jackson I, Varagic Z, Ernst M. A novel GABA(A) receptor pharmacology: drugs interacting with the α(+) β(-) interface. Br J Pharmacol 2012; 166:476-85. [PMID: 22074382 DOI: 10.1111/j.1476-5381.2011.01779.x] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
GABA(A) receptors are ligand-gated chloride channels composed of five subunits that can belong to different subunit classes. The existence of 19 different subunits gives rise to a multiplicity of GABA(A) receptor subtypes with distinct subunit composition; regional, cellular and subcellular distribution; and pharmacology. Most of these receptors are composed of two α, two β and one γ2 subunits. GABA(A) receptors are the site of action of a variety of pharmacologically and clinically important drugs, such as benzodiazepines, barbiturates, neuroactive steroids, anaesthetics and convulsants. Whereas GABA acts at the two extracellular β(+) α(-) interfaces of GABA(A) receptors, the allosteric modulatory benzodiazepines interact with the extracellular α(+) γ2(-) interface. In contrast, barbiturates, neuroactive steroids and anaesthetics seem to interact with solvent accessible pockets in the transmembrane domain. Several benzodiazepine site ligands have been identified that selectively interact with GABA(A) receptor subtypes containing α2βγ2, α3βγ2 or α5βγ2 subunits. This indicates that the different α subunit types present in these receptors convey sufficient structural differences to the benzodiazepine binding site to allow specific interaction with certain benzodiazepine site ligands. Recently, a novel drug binding site was identified at the α(+) β(-) interface. This binding site is homologous to the benzodiazepine binding site at the α(+) γ2(-) interface and is thus also strongly influenced by the type of α subunit present in the receptor. Drugs interacting with this binding site cannot directly activate but only allosterically modulate GABA(A) receptors. The possible importance of such drugs addressing a spectrum of receptor subtypes completely different from that of benzodiazepines is discussed.
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Affiliation(s)
- Werner Sieghart
- Department of Biochemistry and Molecular Biology, Center for Brain Research, Medical University Vienna, Vienna, Austria
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Absalom N, Eghorn LF, Villumsen IS, Karim N, Bay T, Olsen JV, Knudsen GM, Bräuner-Osborne H, Frølund B, Clausen RP, Chebib M, Wellendorph P. α4βδ GABA(A) receptors are high-affinity targets for γ-hydroxybutyric acid (GHB). Proc Natl Acad Sci U S A 2012; 109:13404-9. [PMID: 22753476 PMCID: PMC3421209 DOI: 10.1073/pnas.1204376109] [Citation(s) in RCA: 77] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
γ-Hydroxybutyric acid (GHB) binding to brain-specific high-affinity sites is well-established and proposed to explain both physiological and pharmacological actions. However, the mechanistic links between these lines of data are unknown. To identify molecular targets for specific GHB high-affinity binding, we undertook photolinking studies combined with proteomic analyses and identified several GABA(A) receptor subunits as possible candidates. A subsequent functional screening of various recombinant GABA(A) receptors in Xenopus laevis oocytes using the two-electrode voltage clamp technique showed GHB to be a partial agonist at αβδ- but not αβγ-receptors, proving that the δ-subunit is essential for potency and efficacy. GHB showed preference for α4 over α(1,2,6)-subunits and preferably activated α4β1δ (EC(50) = 140 nM) over α4β(2/3)δ (EC(50) = 8.41/1.03 mM). Introduction of a mutation, α4F71L, in α4β1(δ)-receptors completely abolished GHB but not GABA function, indicating nonidentical binding sites. Radioligand binding studies using the specific GHB radioligand [(3)H](E,RS)-(6,7,8,9-tetrahydro-5-hydroxy-5H-benzocyclohept-6-ylidene)acetic acid showed a 39% reduction (P = 0.0056) in the number of binding sites in α4 KO brain tissue compared with WT controls, corroborating the direct involvement of the α4-subunit in high-affinity GHB binding. Our data link specific GHB forebrain binding sites with α4-containing GABA(A) receptors and postulate a role for extrasynaptic α4δ-containing GABA(A) receptors in GHB pharmacology and physiology. This finding will aid in elucidating the molecular mechanisms behind the proposed function of GHB as a neurotransmitter and its unique therapeutic effects in narcolepsy and alcoholism.
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Affiliation(s)
- Nathan Absalom
- Faculty of Pharmacy A15, University of Sydney, Sydney, New South Wales 2006, Australia
| | - Laura F. Eghorn
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, 2100 Copenhagen, Denmark
| | - Inge S. Villumsen
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, 2100 Copenhagen, Denmark
| | - Nasiara Karim
- Faculty of Pharmacy A15, University of Sydney, Sydney, New South Wales 2006, Australia
| | - Tina Bay
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, 2100 Copenhagen, Denmark
| | - Jesper V. Olsen
- Novo Nordisk Foundation Center for Protein Research, Faculty of Health and Medical Sciences, University of Copenhagen, 2200 Copenhagen, Denmark; and
| | - Gitte M. Knudsen
- Neurobiology Research Unit and Center for Integrated Molecular Brain Imaging (Cimbi), Rigshospitalet and University of Copenhagen, 2100 Copenhagen, Denmark
| | - Hans Bräuner-Osborne
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, 2100 Copenhagen, Denmark
| | - Bente Frølund
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, 2100 Copenhagen, Denmark
| | - Rasmus P. Clausen
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, 2100 Copenhagen, Denmark
| | - Mary Chebib
- Faculty of Pharmacy A15, University of Sydney, Sydney, New South Wales 2006, Australia
| | - Petrine Wellendorph
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, 2100 Copenhagen, Denmark
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Yanovsky Y, Schubring SR, Yao Q, Zhao Y, Li S, May A, Haas HL, Lin JS, Sergeeva OA. Waking action of ursodeoxycholic acid (UDCA) involves histamine and GABAA receptor block. PLoS One 2012; 7:e42512. [PMID: 22880010 PMCID: PMC3412845 DOI: 10.1371/journal.pone.0042512] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2011] [Accepted: 07/09/2012] [Indexed: 01/10/2023] Open
Abstract
Since ancient times ursodeoxycholic acid (UDCA), a constituent of bile, is used against gallstone formation and cholestasis. A neuroprotective action of UDCA was demonstrated recently in models of Alzheimer's disease and retinal degeneration. The mechanisms of UDCA action in the nervous system are poorly understood. We show now that UDCA promotes wakefulness during the active period of the day, lacking this activity in histamine-deficient mice. In cultured hypothalamic neurons UDCA did not affect firing rate but synchronized the firing, an effect abolished by the GABAAR antagonist gabazine. In histaminergic neurons recorded in slices UDCA reduced amplitude and duration of spontaneous and evoked IPSCs. In acutely isolated histaminergic neurons UDCA inhibited GABA-evoked currents and sIPSCs starting at 10 µM (IC50 = 70 µM) and did not affect NMDA- and AMPA-receptor mediated currents at 100 µM. Recombinant GABAA receptors composed of α1, β1–3 and γ2L subunits expressed in HEK293 cells displayed a sensitivity to UDCA similar to that of native GABAA receptors. The mutation α1V256S, known to reduce the inhibitory action of pregnenolone sulphate, reduced the potency of UDCA. The mutation α1Q241L, which abolishes GABAAR potentiation by several neurosteroids, had no effect on GABAAR inhibition by UDCA. In conclusion, UDCA enhances alertness through disinhibition, at least partially of the histaminergic system via GABAA receptors.
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Affiliation(s)
- Yevgenij Yanovsky
- Department of Neurophysiology, Medical Faculty, Heinrich-Heine-University, Dusseldorf, Germany
| | - Stephan R. Schubring
- Department of Neurophysiology, Medical Faculty, Heinrich-Heine-University, Dusseldorf, Germany
| | - Quiaoling Yao
- Integrative Physiology of Brain Arousal Systems, Lyon Neuroscience Research Center, INSERM U1028-CNRS UMR 5292, Faculty of Medicine, Claude Bernard University, Lyon, France
| | - Yan Zhao
- Integrative Physiology of Brain Arousal Systems, Lyon Neuroscience Research Center, INSERM U1028-CNRS UMR 5292, Faculty of Medicine, Claude Bernard University, Lyon, France
| | - Sha Li
- Department of Neurophysiology, Medical Faculty, Heinrich-Heine-University, Dusseldorf, Germany
- Integrative Physiology of Brain Arousal Systems, Lyon Neuroscience Research Center, INSERM U1028-CNRS UMR 5292, Faculty of Medicine, Claude Bernard University, Lyon, France
| | - Andrea May
- Department of Neurophysiology, Medical Faculty, Heinrich-Heine-University, Dusseldorf, Germany
| | - Helmut L. Haas
- Department of Neurophysiology, Medical Faculty, Heinrich-Heine-University, Dusseldorf, Germany
| | - Jian-Sheng Lin
- Integrative Physiology of Brain Arousal Systems, Lyon Neuroscience Research Center, INSERM U1028-CNRS UMR 5292, Faculty of Medicine, Claude Bernard University, Lyon, France
| | - Olga A. Sergeeva
- Department of Neurophysiology, Medical Faculty, Heinrich-Heine-University, Dusseldorf, Germany
- * E-mail:
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Yanovsky Y, Zigman JM, Kernder A, Bein A, Sakata I, Osborne-Lawrence S, Haas HL, Sergeeva OA. Proton- and ammonium-sensing by histaminergic neurons controlling wakefulness. Front Syst Neurosci 2012; 6:23. [PMID: 22509157 PMCID: PMC3325548 DOI: 10.3389/fnsys.2012.00023] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2012] [Accepted: 03/21/2012] [Indexed: 11/29/2022] Open
Abstract
The histaminergic neurons in the tuberomamillary nucleus (TMN) of the posterior hypothalamus are involved in the control of arousal. These neurons are sensitive to hypercapnia as has been shown in experiments examining c-Fos expression, a marker for increased neuronal activity. We investigated the mechanisms through which TMN neurons respond to changes in extracellular levels of acid/CO2. Recordings in rat brain slices revealed that acidification within the physiological range (pH from 7.4 to 7.0), as well as ammonium chloride (5 mM), excite histaminergic neurons. This excitation is significantly reduced by antagonists of type I metabotropic glutamate receptors and abolished by benzamil, an antagonist of acid-sensing ion channels (ASICs) and Na+/Ca2+ exchanger, or by ouabain which blocks Na+/K+ ATPase. We detected variable combinations of 4 known types of ASICs in single TMN neurons, and observed activation of ASICs in single dissociated TMN neurons only at pH lower than 7.0. Thus, glutamate, which is known to be released by glial cells and orexinergic neurons, amplifies the acid/CO2-induced activation of TMN neurons. This amplification demands the coordinated function of metabotropic glutamate receptors, Na+/Ca2+ exchanger and Na+/K+ ATPase. We also developed a novel HDC-Cre transgenic reporter mouse line in which histaminergic TMN neurons can be visualized. In contrast to the rat, the mouse histaminergic neurons lacked the pH 7.0-induced excitation and displayed only a minimal response to the mGluR I agonist DHPG (0.5 μM). On the other hand, ammonium-induced excitation was similar in mouse and rat. These results are relevant for the understanding of the neuronal mechanisms controlling acid/CO2-induced arousal in hepatic encephalopathy and obstructive sleep apnoea. Moreover, the new HDC-Cre mouse model will be a useful tool for studying the physiological and pathophysiological roles of the histaminergic system.
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Affiliation(s)
- Yevgenij Yanovsky
- Medical Faculty, Molecular Neurophysiology, Heinrich-Heine University Duesseldorf, Germany
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Schubring SR, Fleischer W, Lin JS, Haas HL, Sergeeva OA. The bile steroid chenodeoxycholate is a potent antagonist at NMDA and GABA(A) receptors. Neurosci Lett 2011; 506:322-6. [PMID: 22155097 DOI: 10.1016/j.neulet.2011.11.036] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2011] [Revised: 11/19/2011] [Accepted: 11/21/2011] [Indexed: 01/02/2023]
Abstract
The bile steroids (BS) cholic acid and chenodeoxycholic acid are produced in hepatocytes and in the brain. Nothing is known about neuronal actions of BS. Deficiency in a 27-hydroxylase enzyme coincides with reduced production of chenodeoxycholic acid (CDCA) and a relative increase in cholic acid in an inherited lipid storage disease, cerebrotendinous xanthomatosis, characterized by neurological dysfunctions, which can be treated by dietary CDCA. We have examined the modulation of hypothalamic network activity by nine common BS. Cholate and CDCA significantly reduced the firing of hypothalamic neurons and synchronized network activity with CDCA being nearly 10 times more potent. The synthetic BS dehydrocholate synchronized the activity without affecting the firing rate. Gabazine, a GABA(A) receptor antagonist, occluded synchronization by BS. Whole-cell patch clamp recordings revealed a block of NMDA- and GABA(A)-receptors by BS. Potencies of nine common BS differed between NMDA and GABA(A) receptors, however in both cases they correlated with BS affinities for albumin but not with their lipophilicity, supporting a direct action at ligand gated ion channels. GABAergic synaptic currents displayed a faster decay under BS. Our data provide new insight into extrahepatic functions of BS revealing their neuroactive potential.
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Affiliation(s)
- S R Schubring
- Heinrich-Heine University, Medical Faculty, Molecular Neurophysiology, D-40225 Dusseldorf, Germany
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GABAA receptors involved in sleep and anaesthesia: β1- versus β3-containing assemblies. Pflugers Arch 2011; 463:187-99. [PMID: 21735059 DOI: 10.1007/s00424-011-0988-4] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2011] [Revised: 06/06/2011] [Accepted: 06/15/2011] [Indexed: 12/18/2022]
Abstract
The histaminergic neurons of the posterior hypothalamus (tuberomamillary nucleus-TMN) control wakefulness, and their silencing through activation of GABA(A) receptors (GABA(A)R) induces sleep and is thought to mediate sedation under propofol anaesthesia. We have previously shown that the β1 subunit preferring fragrant dioxane derivatives (FDD) are highly potent modulators of GABA(A)R in TMN neurons. In recombinant receptors containing the β3N265M subunit, FDD action is abolished and GABA potency is reduced. Using rat, wild-type and β3N265M mice, FDD and propofol, we explored the relative contributions of β1- and β3-containing GABA(A)R to synaptic transmission from the GABAergic sleep-on ventrolateral preoptic area neurons to TMN. In β3N265M mice, GABA potency remained unchanged in TMN neurons, but it was decreased in cultured posterior hypothalamic neurons with impaired modulation of GABA(A)R by propofol. Spontaneous and evoked GABAergic synaptic currents (IPSC) showed β1-type pharmacology, with the same effects achieved by 3 μM propofol and 10 μM PI24513. Propofol and the FDD PI24513 suppressed neuronal firing in the majority of neurons at 5 and 100 μM, and in all cells at 10 and 250 μM, respectively. FDD given systemically in mice induced sedation but not anaesthesia. Propofol-induced currents were abolished (1-6 μM) or significantly reduced (12 μM) in β3N265M mice, whereas gating and modulation of GABA(A)R by PI24513 as well as modulation by propofol were unchanged. In conclusion, β1-containing (FDD-sensitive) GABA(A)R represent the major receptor pool in TMN neurons responding to GABA, while β3-containing (FDD-insensitive) receptors are gated by low micromolar doses of propofol. Thus, sleep and anaesthesia depend on different GABA(A)R types.
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Yanovsky Y, Li S, Klyuch BP, Yao Q, Blandina P, Passani MB, Lin JS, Haas HL, Sergeeva OA. L-Dopa activates histaminergic neurons. J Physiol 2011; 589:1349-66. [PMID: 21242252 DOI: 10.1113/jphysiol.2010.203257] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
L-Dopa is the most effective treatment of early and advanced stages of Parkinson's disease (PD), but its chronic use leads to loss of efficiency and dyskinesia. This is delayed by lower dosage at early stages, made possible by additional treatment with histamine antagonists. We present here evidence that histaminergic tuberomamillary nucleus (TMN) neurons, involved in the control of wakefulness, are excited under L-Dopa (EC50 15 μM), express Dopa decarboxylase and show dopamine immunoreactivity. Dopaergic excitation was investigated with patch-clamp recordings from brain slices combined with single-cell RT-PCR analysis of dopamine receptor expression. In addition to the excitatory dopamine 1 (D1)-like receptors, TMN neurons express D2-like receptors, which are coupled through phospholipase C (PLC) to transient receptor potential canonical (TRPC) channels and the Na+/Ca2+ exchanger. D2 receptor activation enhances firing frequency, histamine release in freely moving rats (microdialysis) and wakefulness (EEG recordings). In histamine deficient mice the wake-promoting action of the D2 receptor agonist quinpirole (1 mg kg⁻¹, I.P.) is missing. Thus the histamine neurons can, subsequent to L-Dopa uptake, co-release dopamine and histamine from their widely projecting axons. Taking into consideration the high density of histaminergic fibres and the histamine H3 receptor heteromerization either with D1 or with D2 receptors in the striatum, this study predicts new avenues for PD therapy.
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Affiliation(s)
- Yevgenij Yanovsky
- Department of Neurophysiology, Heinrich-Heine-University, D-40001, Dusseldorf, Germany
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