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Song XJ, Hu JJ. Neurobiological basis of emergence from anesthesia. Trends Neurosci 2024; 47:355-366. [PMID: 38490858 DOI: 10.1016/j.tins.2024.02.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2023] [Revised: 01/25/2024] [Accepted: 02/19/2024] [Indexed: 03/17/2024]
Abstract
The suppression of consciousness by anesthetics and the emergence of the brain from anesthesia are complex and elusive processes. Anesthetics may exert their inhibitory effects by binding to specific protein targets or through membrane-mediated targets, disrupting neural activity and the integrity and function of neural circuits responsible for signal transmission and conscious perception/subjective experience. Emergence from anesthesia was generally thought to depend on the elimination of the anesthetic from the body. Recently, studies have suggested that emergence from anesthesia is a dynamic and active process that can be partially controlled and is independent of the specific molecular targets of anesthetics. This article summarizes the fundamentals of anesthetics' actions in the brain and the mechanisms of emergence from anesthesia that have been recently revealed in animal studies.
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Affiliation(s)
- Xue-Jun Song
- Department of Medical Neuroscience and SUSTech Center for Pain Medicine, Southern University of Science and Technology School of Medicine, Shenzhen, China.
| | - Jiang-Jian Hu
- Department of Medical Neuroscience and SUSTech Center for Pain Medicine, Southern University of Science and Technology School of Medicine, Shenzhen, China
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Mao LM, Thallapureddy K, Wang JQ. Effects of propofol on presynaptic synapsin phosphorylation in the mouse brain in vivo. Brain Res 2024; 1823:148671. [PMID: 37952872 PMCID: PMC10806815 DOI: 10.1016/j.brainres.2023.148671] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2023] [Revised: 10/24/2023] [Accepted: 11/07/2023] [Indexed: 11/14/2023]
Abstract
The commonly used general anesthetic propofol can enhance the γ-aminobutyric acid-mediated inhibitory synaptic transmission and depress the glutamatergic excitatory synaptic transmission to achieve general anesthesia and other outcomes. In addition to the actions at postsynaptic sites, the modulation of presynaptic activity by propofol is thought to contribute to neurophysiological effects of the anesthetic, although potential targets of propofol within presynaptic nerve terminals are incompletely studied at present. In this study, we explored the possible linkage of propofol to synapsins, a family of neuron-specific phosphoproteins which are the most abundant proteins on presynaptic vesicles, in the adult mouse brain in vivo. We found that an intraperitoneal injection of propofol at a dose that caused loss of righting reflex increased basal levels of synapsin phosphorylation at the major representative phosphorylation sites (serine 9, serine 62/67, and serine 603) in the prefrontal cortex (PFC) of male and female mice. Propofol also elevated synapsin phosphorylation at these sites in the striatum and S9 and S62/67 phosphorylation in the hippocampus, while propofol had no effect on tyrosine hydroxylase phosphorylation in striatal nerve terminals. Total synapsin protein expression in the PFC, hippocampus, and striatum was not altered by propofol. These results reveal that synapsin could be a novel substrate of propofol in the presynaptic neurotransmitter release machinery. Propofol possesses the ability to upregulate synapsin phosphorylation in broad mouse brain regions.
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Affiliation(s)
- Li-Min Mao
- Department of Biomedical Sciences, School of Medicine, University of Missouri-Kansas City, Kansas City, MO 64108, USA
| | - Khyathi Thallapureddy
- Department of Biomedical Sciences, School of Medicine, University of Missouri-Kansas City, Kansas City, MO 64108, USA
| | - John Q Wang
- Department of Biomedical Sciences, School of Medicine, University of Missouri-Kansas City, Kansas City, MO 64108, USA; Department of Anesthesiology, School of Medicine, University of Missouri-Kansas City, Kansas City, MO 64108, USA.
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Abdulzahir A, Klein S, Lor C, Perkins MG, Frelka A, Pearce RA. Changes in Memory, Sedation, and Receptor Kinetics Imparted by the β2-N265M and β3-N265M GABAA Receptor Point Mutations. Int J Mol Sci 2023; 24:ijms24065637. [PMID: 36982709 PMCID: PMC10053577 DOI: 10.3390/ijms24065637] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2023] [Revised: 03/10/2023] [Accepted: 03/12/2023] [Indexed: 03/18/2023] Open
Abstract
Point mutations in the β2 (N265S) and β3 (N265M) subunits of γ-amino butyric acid type A receptors (GABAARs) that render them insensitive to the general anesthetics etomidate and propofol have been used to link modulation of β2-GABAARs to sedation and β3-GABAARs to surgical immobility. These mutations also alter GABA sensitivity, and mice carrying the β3-N265M mutation have been reported to have impaired baseline memory. Here, we tested the effects of the β2-N265M and β3-N265M mutations on memory, movement, hotplate sensitivity, anxiety, etomidate-induced sedation, and intrinsic kinetics. We found that both β2-N265M and β3-N265M mice exhibited baseline deficits in the Context Preexposure Facilitation Effect learning paradigm. Exploratory activity was slightly greater in β2-N265M mice, but there were no changes in either genotype in anxiety or hotplate sensitivity. β2-N265M mice were highly resistant to etomidate-induced sedation, and heterozygous mice were partially resistant. In rapid solution exchange experiments, both mutations accelerated deactivation two- to three-fold compared to wild type receptors and prevented modulation by etomidate. This degree of change in the receptor deactivation rate is comparable to that produced by an amnestic dose of etomidate but in the opposite direction, indicating that intrinsic characteristics of GABAARs are optimally tuned under baseline conditions to support mnemonic function.
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Huang X, Cao H, Zhang C, Lan H, Gong X, Li R, Lin Y, Xu B, Chen H, Guan X. The difference in mean arterial pressure induced by remimazolam compared to etomidate in the presence of fentanyl at tracheal intubation: A randomized controlled trial. Front Pharmacol 2023; 14:1143784. [PMID: 37021047 PMCID: PMC10067562 DOI: 10.3389/fphar.2023.1143784] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2023] [Accepted: 03/09/2023] [Indexed: 04/07/2023] Open
Abstract
Background: Combined use of hypnotic and opioids during anesthesia inductions decreases blood pressure. Post-induction hypotension (PIHO) is the most common side effect of anesthesia induction. We aimed to compare the difference in mean arterial pressure (MAP) induced by remimazolam with that induced by etomidate in the presence of fentanyl at tracheal intubation. Methods: We assessed 138 adult patients with American Society of Anesthesiologists physical status I-II who underwent elective urological surgery. Patients were randomly allocated to receive either remimazolam or etomidate as alterative hypnotic in the presence of fentanyl during anesthesia induction. Comparable BIS values were achieved in both groups. The primary outcome was the difference in the MAP at tracheal intubation. The secondary outcomes included the characteristics of anesthesia, surgery, and adverse effects. Results: The MAP was higher in the etomidate group than in the remimazolam group at tracheal intubation (108 [22] mmHg vs. 83 [16] mmHg; mean difference, -26; 95% confidence interval [CI], -33 to -19; p < 0.0001). Heart rate was significantly higher in the etomidate group than in the remimazolam group at tracheal intubation. The patients' condition warranted the administration of ephedrine more frequently in the remimazolam group (22%) than in the etomidate group (5%) (p = 0.0042) during anesthesia induction. The remimazolam group had a lower incidence of hypertension (0% vs. 9%, p = 0.0133), myoclonus (0% vs. 47%, p < 0.001), and tachycardia (16% vs. 35%, p = 0.0148), and a higher incidence of PIHO (42% vs. 5%, p = 0.001) than the etomidate group during anesthesia induction. Conclusion: Remimazolam was associated with lower MAP and lower heart rate compared to etomidate in the presence of fentanyl at tracheal intubation. Patients in the remimazolam group had a higher incidence of PIHO, and their condition warranted the administration of ephedrine more frequently than in the etomidate group during anesthesia induction.
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Affiliation(s)
- Xiaofang Huang
- Department of Anesthesiology, the First Affiliated Hospital of Guangxi Medical University, Nanning, Guangxi, China
| | - Huiyu Cao
- Department of Anesthesiology, the First Affiliated Hospital of Guangxi Medical University, Nanning, Guangxi, China
| | - Cuiwen Zhang
- Department of Anesthesiology, the First Affiliated Hospital of Guangxi Medical University, Nanning, Guangxi, China
| | - Hongmeng Lan
- Department of Anesthesiology, the First Affiliated Hospital of Guangxi Medical University, Nanning, Guangxi, China
| | - Xiaofang Gong
- Department of Anesthesiology, the First Affiliated Hospital of Guangxi Medical University, Nanning, Guangxi, China
| | - Ruijie Li
- Department of Anesthesiology, the First Affiliated Hospital of Guangxi Medical University, Nanning, Guangxi, China
| | - Yan Lin
- Department of Anesthesiology, the First Affiliated Hospital of Guangxi Medical University, Nanning, Guangxi, China
| | - Bing Xu
- Department of Rehabilitation, the People’s Hospital of Guangxi Zhuang Autonomous Region, Nanning, Guangxi, China
| | - Huihe Chen
- Department of Rehabilitation, the First Affiliated Hospital of Guangxi Medical University, Nanning, Guangxi, China
| | - Xuehai Guan
- Department of Anesthesiology, the First Affiliated Hospital of Guangxi Medical University, Nanning, Guangxi, China
- *Correspondence: Xuehai Guan,
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Arias HR, Germann AL, Pierce SR, Sakamoto S, Ortells MO, Hamachi I, Akk G. Modulation of the mammalian GABA A receptor by type I and type II positive allosteric modulators of the α7 nicotinic acetylcholine receptor. Br J Pharmacol 2022; 179:5323-5337. [PMID: 36082615 PMCID: PMC9669183 DOI: 10.1111/bph.15948] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2022] [Revised: 08/29/2022] [Accepted: 09/06/2022] [Indexed: 11/28/2022] Open
Abstract
BACKGROUND AND PURPOSE Positive allosteric modulators of the α7 nicotinic acetylcholine (nACh) receptor (α7-PAMs) possess promnesic and procognitive properties and have potential in the treatment of cognitive and psychiatric disorders including Alzheimer's disease and schizophrenia. Behavioural studies in rodents have indicated that α7-PAMs can also produce antinociceptive and anxiolytic effects that may be associated with positive modulation of the GABAA receptor. The overall goal of this study was to investigate the modulatory actions of selected α7-PAMs on the GABAA receptor. EXPERIMENTAL APPROACH We employed a combination of cell fluorescence imaging, electrophysiology, functional competition and site-directed mutagenesis to investigate the functional and structural mechanisms of modulation of the GABAA receptor by three representative α7-PAMs. KEY RESULTS We show that the α7-PAMs at micromolar concentrations enhance the apparent affinity of the GABAA receptor for the transmitter and potentiate current responses from the receptor. The compounds were equi-effective at binary αβ and ternary αβγ GABAA receptors. Functional competition and site-directed mutagenesis indicate that the α7-PAMs bind to the classic anaesthetic binding sites in the transmembrane region in the intersubunit interfaces, which results in stabilization of the active state of the receptor. CONCLUSION AND IMPLICATIONS We conclude that the tested α7-PAMs are micromolar-affinity, intermediate- to low-efficacy allosteric potentiators of the mammalian αβγ GABAA receptor. Given the similarities in the in vitro sensitivities of the α7 nACh and α1β2γ2L GABAA receptors to α7-PAMs, we propose that doses used to produce nACh receptor-mediated behavioural effects in vivo are likely to modulate GABAA receptor function.
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Affiliation(s)
- Hugo R. Arias
- Department of Pharmacology and Physiology, Oklahoma State University College of Osteopathic Medicine, Tahlequah, OK, USA
| | - Allison L. Germann
- Department of Anesthesiology, Washington University School of Medicine, St. Louis, MO, USA
| | - Spencer R. Pierce
- Department of Anesthesiology, Washington University School of Medicine, St. Louis, MO, USA
| | - Seiji Sakamoto
- Department of Synthetic Chemistry and Biological Chemistry, Graduate School of Engineering, Kyoto University, Kyoto, Japan
| | - Marcelo O. Ortells
- Facultad de Medicina, Universidad de Morón, Morón, and CONICET, Argentina
| | - Itaru Hamachi
- Department of Synthetic Chemistry and Biological Chemistry, Graduate School of Engineering, Kyoto University, Kyoto, Japan
| | - Gustav Akk
- Department of Anesthesiology, Washington University School of Medicine, St. Louis, MO, USA
- The Taylor Family Institute for Innovative Psychiatric Research, Washington University School of Medicine, St. Louis, MO, USA
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Vien TN, Ackley MA, Doherty JJ, Moss SJ, Davies PA. Preventing Phosphorylation of the GABAAR β3 Subunit Compromises the Behavioral Effects of Neuroactive Steroids. Front Mol Neurosci 2022; 15:817996. [PMID: 35431797 PMCID: PMC9009507 DOI: 10.3389/fnmol.2022.817996] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2021] [Accepted: 03/09/2022] [Indexed: 11/26/2022] Open
Abstract
Neuroactive steroids (NASs) have potent anxiolytic, anticonvulsant, sedative, and hypnotic actions, that reflect in part their efficacy as GABAAR positive allosteric modulators (PAM). In addition to this, NAS exert metabotropic effects on GABAergic inhibition via the activation of membrane progesterone receptors (mPRs), which are G-protein coupled receptors. mPR activation enhances the phosphorylation of residues serine 408 and 409 (S408/9) in the β3 subunit of GABAARs, increasing their accumulation in the plasma membrane leading to a sustained increase in tonic inhibition. To explore the significance of NAS-induced phosphorylation of GABAARs, we used mice in which S408/9 in the β3 subunit have been mutated to alanines, mutations that prevent the metabotropic actions of NASs on GABAAR function while preserving NAS allosteric potentiation of GABAergic current. While the sedative actions of NAS were comparable to WT, their anxiolytic actions were reduced in S408/9A mice. Although the induction of hypnosis by NAS were maintained in the mutant mice the duration of the loss of righting reflex was significantly shortened. Finally, ability of NAS to terminate diazepam pharmacoresistant seizures was abolished in S408/9A mice. In conclusion, our results suggest that S408/9 in the GABAAR β3 subunit contribute to the anxiolytic and anticonvulsant efficacy of NAS, in addition to their ability to regulate the loss of righting reflex.
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Affiliation(s)
- Thuy N. Vien
- Department of Neuroscience, Tufts University School of Medicine, Boston, MA, United States
| | - Michael A. Ackley
- Research and Non-clinical Development, Sage Therapeutics, Inc., Cambridge, MA, United States
| | - James J. Doherty
- Research and Non-clinical Development, Sage Therapeutics, Inc., Cambridge, MA, United States
| | - Stephen J. Moss
- Department of Neuroscience, Tufts University School of Medicine, Boston, MA, United States
- *Correspondence: Stephen J. Moss,
| | - Paul A. Davies
- Department of Neuroscience, Tufts University School of Medicine, Boston, MA, United States
- Paul A. Davies,
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Arias HR, Borghese CM, Germann AL, Pierce SR, Bonardi A, Nocentini A, Gratteri P, Thodati TM, Lim NJ, Adron Harris R, Akk G. (+)-Catharanthine potentiates the GABA A receptor by binding to a transmembrane site at the β(+)/α(-) interface near the TM2-TM3 loop. Biochem Pharmacol 2022; 199:114993. [PMID: 35304861 PMCID: PMC9178925 DOI: 10.1016/j.bcp.2022.114993] [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: 01/06/2022] [Revised: 03/09/2022] [Accepted: 03/10/2022] [Indexed: 11/17/2022]
Abstract
(+)-Catharanthine, a coronaridine congener, potentiates the γ-aminobutyric acid type A receptor (GABAAR) and induces sedation through a non-benzodiazepine mechanism, but the specific site of action and intrinsic mechanism have not beendefined. Here, we describe GABAAR subtype selectivity and location of the putative binding site for (+)-catharanthine using electrophysiological, site-directed mutagenesis, functional competition, and molecular docking experiments. Electrophysiological and in silico experiments showed that (+)-catharanthine potentiates the responses to low, subsaturating GABA at β2/3-containing GABAARs 2.4-3.5 times more efficaciously than at β1-containing GABAARs. The activity of (+)-catharanthine is reduced by the β2(N265S) mutation that decreases GABAAR potentiation by loreclezole, but not by the β3(M286C) or α1(Q241L) mutations that reduce receptor potentiation by R(+)-etomidate or neurosteroids, respectively. Competitive functional experiments indicated that the binding site for (+)-catharanthine overlaps that for loreclezole, but not those for R(+)-etomidate or potentiating neurosteroids. Molecular docking experiments suggested that (+)-catharanthine binds at the β(+)/α(-) intersubunit interface near the TM2-TM3 loop, where it forms H-bonds with β2-D282 (TM3), β2-K279 (TM2-TM3 loop), and β2-N265 and β2-R269 (TM2). Site-directed mutagenesis experiments supported the in silico results, demonstrating that the K279A and D282A substitutions, that lead to a loss of H-bonding ability of the mutated residue, and the N265S mutation, impair the gating efficacy of (+)-catharanthine. We infer that (+)-catharanthine potentiates the GABAAR through several H-bond interactions with a binding site located in the β(+)/α(-) interface in the transmembrane domain, near the TM2-TM3 loop, where it overlaps with loreclezole binding site.
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Affiliation(s)
- Hugo R Arias
- Department of Pharmacology and Physiology, Oklahoma State University College of Osteopathic Medicine, Tahlequah, OK, USA.
| | - Cecilia M Borghese
- Waggoner Center for Alcohol and Addiction Research, The University of Texas at Austin, Austin, TX, USA.
| | - Allison L Germann
- Department of Anesthesiology, the Taylor Family Institute for Innovative Psychiatric Research, Washington University School of Medicine, St. Louis, MO, USA.
| | - Spencer R Pierce
- Department of Anesthesiology, the Taylor Family Institute for Innovative Psychiatric Research, Washington University School of Medicine, St. Louis, MO, USA.
| | - Alessandro Bonardi
- Department of Neurosciences, Psychology, Drug Research and Child Health (NEUROFARBA), Section of Pharmaceutical and Nutraceutical Sciences, Laboratory of Molecular Modeling Cheminformatics & QSAR, University of Florence, Florence, Italy.
| | - Alessio Nocentini
- Department of Neurosciences, Psychology, Drug Research and Child Health (NEUROFARBA), Section of Pharmaceutical and Nutraceutical Sciences, Laboratory of Molecular Modeling Cheminformatics & QSAR, University of Florence, Florence, Italy.
| | - Paola Gratteri
- Department of Neurosciences, Psychology, Drug Research and Child Health (NEUROFARBA), Section of Pharmaceutical and Nutraceutical Sciences, Laboratory of Molecular Modeling Cheminformatics & QSAR, University of Florence, Florence, Italy.
| | - Thanvi M Thodati
- Waggoner Center for Alcohol and Addiction Research, The University of Texas at Austin, Austin, TX, USA.
| | - Natalie J Lim
- Waggoner Center for Alcohol and Addiction Research, The University of Texas at Austin, Austin, TX, USA.
| | - R Adron Harris
- Waggoner Center for Alcohol and Addiction Research, The University of Texas at Austin, Austin, TX, USA.
| | - Gustav Akk
- Department of Anesthesiology, the Taylor Family Institute for Innovative Psychiatric Research, Washington University School of Medicine, St. Louis, MO, USA.
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Figueroa AG, Benkwitz C, Surges G, Kunz N, Homanics GE, Pearce RA. Hippocampal β2-GABA A receptors mediate LTP suppression by etomidate and contribute to long-lasting feedback but not feedforward inhibition of pyramidal neurons. J Neurophysiol 2021; 126:1090-1100. [PMID: 34406874 PMCID: PMC8560413 DOI: 10.1152/jn.00303.2021] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The general anesthetic etomidate, which acts through γ-aminobutyric acid type A (GABAA) receptors, impairs the formation of new memories under anesthesia. This study addresses the molecular and cellular mechanisms by which this occurs. Here, using a new line of genetically engineered mice carrying the GABAA receptor (GABAAR) β2-N265M mutation, we tested the roles of receptors that incorporate GABAA receptor β2 versus β3 subunits to suppression of long-term potentiation (LTP), a cellular model of learning and memory. We found that brain slices from β2-N265M mice resisted etomidate suppression of LTP, indicating that the β2-GABAARs are an essential target in this model. As these receptors are most heavily expressed by interneurons in the hippocampus, this finding supports a role for interneuron modulation in etomidate control of synaptic plasticity. Nevertheless, β2 subunits are also expressed by pyramidal neurons, so they might also contribute. Therefore, using a previously established line of β3-N265M mice, we also examined the contributions of β2- versus β3-GABAARs to GABAA,slow dendritic inhibition, because dendritic inhibition is particularly well suited to controlling synaptic plasticity. We also examined their roles in long-lasting suppression of population activity through feedforward and feedback inhibition. We found that both β2- and β3-GABAARs contribute to GABAA,slow inhibition and that both β2- and β3-GABAARs contribute to feedback inhibition, whereas only β3-GABAARs contribute to feedforward inhibition. We conclude that modulation of β2-GABAARs is essential to etomidate suppression of LTP. Furthermore, to the extent that this occurs through GABAARs on pyramidal neurons, it is through modulation of feedback inhibition.NEW & NOTEWORTHY Etomidate exerts its anesthetic actions through GABAA receptors. However, the mechanism remains unknown. Here, using a hippocampal brain slice model, we show that β2-GABAARs are essential to this effect. We also show that these receptors contribute to long-lasting dendritic inhibition in feedback but not feedforward inhibition of pyramidal neurons. These findings hold implications for understanding how anesthetics block memory formation and, more generally, how inhibitory circuits control learning and memory.
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Affiliation(s)
- Alexander G Figueroa
- Department of Anesthesiology, University of Wisconsin-Madison, Madison, Wisconsin
| | - Claudia Benkwitz
- Department of Anesthesiology, University of Wisconsin-Madison, Madison, Wisconsin.,Department of Anesthesiology and Perioperative Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Gabe Surges
- Department of Anesthesiology, University of Wisconsin-Madison, Madison, Wisconsin
| | - Nicholas Kunz
- Department of Anesthesiology and Perioperative Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Gregg E Homanics
- Department of Anesthesiology and Perioperative Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Robert A Pearce
- Department of Anesthesiology, University of Wisconsin-Madison, Madison, Wisconsin
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Bönisch H, Fink KB, Malinowska B, Molderings GJ, Schlicker E. Serotonin and beyond-a tribute to Manfred Göthert (1939-2019). NAUNYN-SCHMIEDEBERG'S ARCHIVES OF PHARMACOLOGY 2021; 394:1829-1867. [PMID: 33991216 PMCID: PMC8376721 DOI: 10.1007/s00210-021-02083-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/23/2021] [Accepted: 03/29/2021] [Indexed: 01/13/2023]
Abstract
Manfred Göthert, who had served Naunyn-Schmiedeberg's Arch Pharmacol as Managing Editor from 1998 to 2005, deceased in June 2019. His scientific oeuvre encompasses more than 20 types of presynaptic receptors, mostly on serotoninergic and noradrenergic neurones. He was the first to identify presynaptic receptors for somatostatin and ACTH and described many presynaptic receptors, known from animal preparations, also in human tissue. In particular, he elucidated the pharmacology of presynaptic 5-HT receptors. A second field of interest included ligand-gated and voltage-dependent channels. The negative allosteric effect of anesthetics at peripheral nACh receptors is relevant for the peripheral clinical effects of these drugs and modified the Meyer-Overton hypothesis. The negative allosteric effect of ethanol at NMDA receptors in human brain tissue occurred at concentrations found in the range of clinical ethanol intoxication. Moreover, the inhibitory effect of gabapentinoids on P/Q Ca2+ channels and the subsequent decrease in AMPA-induced noradrenaline release may contribute to their clinical effect. Another ligand-gated ion channel, the 5-HT3 receptor, attracted the interest of Manfred Göthert from the whole animal via isolated preparations down to the cellular level. He contributed to that molecular study in which 5-HT3 receptor subtypes were disclosed. Finally, he found altered pharmacological properties of 5-HT receptor variants like the Arg219Leu 5-HT1A receptor (which was also shown to be associated with major depression) and the Phe124Cys 5-HT1B receptor (which may be related to sumatriptan-induced vasospasm). Manfred Göthert was a brilliant scientist and his papers have a major impact on today's pharmacology.
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Affiliation(s)
- H Bönisch
- Institute of Pharmacology and Toxicology, University of Bonn, Venusberg-Campus 1, 53105, Bonn, Germany
| | - K B Fink
- Merz Pharmaceuticals, Frankfurt/Main, Germany
| | - B Malinowska
- Department of Physiology and Pathophysiology, Medical University of Białystok, Białystok, Poland
| | - G J Molderings
- Institute of Human Genetics, University of Bonn, Bonn, Germany
| | - E Schlicker
- Institute of Pharmacology and Toxicology, University of Bonn, Venusberg-Campus 1, 53105, Bonn, Germany.
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10
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Ghit A, Assal D, Al-Shami AS, Hussein DEE. GABA A receptors: structure, function, pharmacology, and related disorders. J Genet Eng Biotechnol 2021; 19:123. [PMID: 34417930 PMCID: PMC8380214 DOI: 10.1186/s43141-021-00224-0] [Citation(s) in RCA: 109] [Impact Index Per Article: 36.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2021] [Accepted: 08/08/2021] [Indexed: 02/03/2023]
Abstract
Background γ-Aminobutyric acid sub-type A receptors (GABAARs) are the most prominent inhibitory neurotransmitter receptors in the CNS. They are a family of ligand-gated ion channel with significant physiological and therapeutic implications. Main body GABAARs are heteropentamers formed from a selection of 19 subunits: six α (alpha1-6), three β (beta1-3), three γ (gamma1-3), three ρ (rho1-3), and one each of the δ (delta), ε (epsilon), π (pi), and θ (theta) which result in the production of a considerable number of receptor isoforms. Each isoform exhibits distinct pharmacological and physiological properties. However, the majority of GABAARs are composed of two α subunits, two β subunits, and one γ subunit arranged as γ2β2α1β2α1 counterclockwise around the center. The mature receptor has a central chloride ion channel gated by GABA neurotransmitter and modulated by a variety of different drugs. Changes in GABA synthesis or release may have a significant effect on normal brain function. Furthermore, The molecular interactions and pharmacological effects caused by drugs are extremely complex. This is due to the structural heterogeneity of the receptors, and the existence of multiple allosteric binding sites as well as a wide range of ligands that can bind to them. Notably, dysfunction of the GABAergic system contributes to the development of several diseases. Therefore, understanding the relationship between GABAA receptor deficits and CNS disorders thus has a significant impact on the discovery of disease pathogenesis and drug development. Conclusion To date, few reviews have discussed GABAA receptors in detail. Accordingly, this review aims to summarize the current understanding of the structural, physiological, and pharmacological properties of GABAARs, as well as shedding light on the most common associated disorders.
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Affiliation(s)
- Amr Ghit
- Department of Biology and Biotechnology, University of Pavia, Pavia, Italy. .,Department of Biotechnology, Institute of Graduate Studies and Research (IGSR), Alexandria University, Alexandria, Egypt.
| | - Dina Assal
- Department of Biotechnology, American University in Cairo (AUC), Cairo, Egypt
| | - Ahmed S Al-Shami
- Department of Biotechnology, Institute of Graduate Studies and Research (IGSR), Alexandria University, Alexandria, Egypt.,Department of Zoology, Faculty of Science, Alexandria University, Alexandria, Egypt
| | - Diaa Eldin E Hussein
- Animal Health Research Institute (AHRI), Agricultural Research Center (ARC), Port of Alexandria, Alexandria, Egypt
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11
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Platholi J, Hemmings HC. Effects of general anesthetics on synaptic transmission and plasticity. Curr Neuropharmacol 2021; 20:27-54. [PMID: 34344292 PMCID: PMC9199550 DOI: 10.2174/1570159x19666210803105232] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2021] [Revised: 07/26/2021] [Accepted: 08/02/2021] [Indexed: 11/22/2022] Open
Abstract
General anesthetics depress excitatory and/or enhance inhibitory synaptic transmission principally by modulating the function of glutamatergic or GABAergic synapses, respectively, with relative anesthetic agent-specific mechanisms. Synaptic signaling proteins, including ligand- and voltage-gated ion channels, are targeted by general anesthetics to modulate various synaptic mechanisms, including presynaptic neurotransmitter release, postsynaptic receptor signaling, and dendritic spine dynamics to produce their characteristic acute neurophysiological effects. As synaptic structure and plasticity mediate higher-order functions such as learning and memory, long-term synaptic dysfunction following anesthesia may lead to undesirable neurocognitive consequences depending on the specific anesthetic agent and the vulnerability of the population. Here we review the cellular and molecular mechanisms of transient and persistent general anesthetic alterations of synaptic transmission and plasticity.
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Affiliation(s)
- Jimcy Platholi
- Cornell University Joan and Sanford I Weill Medical College Ringgold standard institution - Anesthesiology New York, New York. United States
| | - Hugh C Hemmings
- Cornell University Joan and Sanford I Weill Medical College Ringgold standard institution - Anesthesiology New York, New York. United States
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12
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Maclura tinctoria Extracts: In Vitro Antibacterial Activity against Aeromonas hydrophila and Sedative Effect in Rhamdia quelen. FISHES 2021. [DOI: 10.3390/fishes6030025] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Maclura tinctoria is a tree species native from Brazil and rich in phenolic compounds. Since plant antibacterial activity is highly associated with phenolic compound concentration, we aim to evaluate the in vitro antimicrobial activity of different extracts against fish pathogenic bacteria. In addition, some phenolic compounds have central depressant effects and can be useful in aquaculture due to possible sedative and/or anesthetic effects. Four M. tinctoria extracts were extracted separately with ethanol; leaves (LE), bark (BE), heartwood (HE), and the sapwood (SE). In vitro antimicrobial activity was tested against Aeromonas strains at concentrations of 6400 to 3.125 μg/mL. The sedative effect was evaluated for 24 h with 30 and 100 mg/L concentrations. Chemical composition was analyzed by HPLC-DAD-MS. The HE extract had the best MIC (400 µg/mL) and MBC (800 µg/mL) compared to the LE, BE, and SE extracts. LE extract induced deep sedation and the BE, SE, and HE extracts induced light sedation. Additionally, BE, SE, and HE induced a normal behavior without side effects. Polyphenolic compounds with antimicrobial activity and sedative effects were identified mainly in HE. Thus, HE extract is safe and can be used as a sedative for silver catfish.
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13
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Liu Y, Chen B, Cai Y, Han Y, Xia Y, Li N, Fan B, Yuan T, Jiang J, Gao PO, Yu W, Jiao Y, Li W. Activation of anterior thalamic reticular nucleus GABAergic neurons promotes arousal from propofol anesthesia in mice. Acta Biochim Biophys Sin (Shanghai) 2021; 53:883-892. [PMID: 33929026 DOI: 10.1093/abbs/gmab056] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2021] [Indexed: 11/14/2022] Open
Abstract
Propofol is widely used for the induction and maintenance of anesthesia, which causes a rapid loss of consciousness. However, the mechanisms underlying the hypnosis effect of propofol are still not fully understood. The thalamic reticular nucleus (TRN) is crucial for regulating wakefulness, sleep rhythm generation, and sleep stability, while the role of TRN in the process of propofol-induced anesthesia is still unknown. Here, we investigated the function of the anterior TRN in propofol general anesthesia. Our results demonstrated that the neural activity of anterior TRN is suppressed during propofol anesthesia, whereas it is robustly activated from anesthesia by recording the calcium signals using fiber photometry technology. The results showed that the activation of anterior TRN neurons by chemogenetic and optogenetic methods shortens the emergency time without changing the induction time. Conversely, chemogenetic or optogenetic inhibition of the TRN neurons leads to a delay in the recovery time. Our study showed that anterior TRN is crucial for behavioral arousal without affecting the induction time of propofol anesthesia.
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Affiliation(s)
- Yanjun Liu
- Department of Anesthesiology, Eye and ENT Hospital, Fudan University, Shanghai 200031, China
| | - Bing Chen
- Department of Anesthesiology, Eye and ENT Hospital, Fudan University, Shanghai 200031, China
| | - Yirong Cai
- Department of Anesthesiology, Eye and ENT Hospital, Fudan University, Shanghai 200031, China
| | - Yuan Han
- Department of Anesthesiology, Eye and ENT Hospital, Fudan University, Shanghai 200031, China
| | - Ying Xia
- Department of Anesthesiology, Eye and ENT Hospital, Fudan University, Shanghai 200031, China
| | - Nanqi Li
- Department of Anesthesiology, Eye and ENT Hospital, Fudan University, Shanghai 200031, China
| | - Bingqian Fan
- Department of Anesthesiology, Eye and ENT Hospital, Fudan University, Shanghai 200031, China
| | - Tianjie Yuan
- Department of Anesthesiology, Eye and ENT Hospital, Fudan University, Shanghai 200031, China
| | - Junli Jiang
- Department of Anesthesiology, Renji Hospital, School of Medicine, Shanghai Jiaotong University, Shanghai 200127, China
| | - P o Gao
- Department of Anesthesiology, Renji Hospital, School of Medicine, Shanghai Jiaotong University, Shanghai 200127, China
| | - Weifeng Yu
- Department of Anesthesiology, Renji Hospital, School of Medicine, Shanghai Jiaotong University, Shanghai 200127, China
| | - Yingfu Jiao
- Department of Anesthesiology, Renji Hospital, School of Medicine, Shanghai Jiaotong University, Shanghai 200127, China
| | - Wenxian Li
- Department of Anesthesiology, Eye and ENT Hospital, Fudan University, Shanghai 200031, China
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14
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Kim JJ, Hibbs RE. Direct Structural Insights into GABA A Receptor Pharmacology. Trends Biochem Sci 2021; 46:502-517. [PMID: 33674151 DOI: 10.1016/j.tibs.2021.01.011] [Citation(s) in RCA: 44] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2020] [Revised: 01/08/2021] [Accepted: 01/25/2021] [Indexed: 12/18/2022]
Abstract
GABAA receptors are pentameric ligand-gated ion channels that mediate most fast neuronal inhibition in the brain. In addition to their important physiological roles, they are noteworthy in their rich pharmacology; prominent drugs used for anxiety, insomnia, and general anesthesia act through positive modulation of GABAA receptors. Direct structural information for how these drugs work was absent until recently. Efforts in structural biology over the past few years have revealed how important drug classes and natural products interact with the GABAA receptor, providing a foundation for studies in dynamics and structure-guided drug design. Here, we review recent developments in GABAA receptor structural pharmacology, focusing on subunit assemblies of the receptor found at synapses.
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Affiliation(s)
- Jeong Joo Kim
- Department of Neuroscience, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Ryan E Hibbs
- Department of Neuroscience, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA.
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15
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Lor C, Perouansky M, Pearce RA. Isoflurane Potentiation of GABA A Receptors Is Reduced but Not Eliminated by the β3(N265M) Mutation. Int J Mol Sci 2020; 21:ijms21249534. [PMID: 33333797 PMCID: PMC7765171 DOI: 10.3390/ijms21249534] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2020] [Revised: 12/10/2020] [Accepted: 12/11/2020] [Indexed: 12/16/2022] Open
Abstract
Background: Mice carrying the GABAA receptor β3(N265M) point mutation, which renders receptors incorporating β3-subunits insensitive to many general anesthetics, have been used experimentally to link modulation of different receptor subtypes to distinct behavioral endpoints. Remarkably, however, the effect of the mutation on the susceptibility to modulation by isoflurane (a standard reference agent for inhalational vapors) has never been tested directly. Therefore, we compared the modulation by isoflurane of expressed α5β3(N265M)γ2L receptors with their wild type counterparts. Methods: Using whole-cell electrophysiological recording and rapid solution exchange techniques, we tested the effects of isoflurane at concentrations ranging from 80 μM to 320 μM on currents activated by 1 μM GABA. We measured drug modulation of wild-type α5β3γ2L GABAA receptors and their counterparts harboring the β3(N265M) mutation. Results: Currents elicited by GABA were enhanced two- to four-fold by isoflurane, in a concentration-dependent manner. Under the same conditions, receptors incorporating the β3(N265M) mutation were enhanced by approximately 1.5- to two-fold; i.e., modulation by isoflurane was attenuated by approximately one-half. Direct activation by isoflurane was also present in mutant receptors but also attenuated. Conclusions: In contrast to the complete insensitivity of β3(N265M) mutant receptors to etomidate and propofol, the mutation has only a partial effect on receptor modulation by isoflurane. Therefore, the persistence of isoflurane effects in mutant mice does not exclude a possible contribution of β3-GABAA receptors.
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16
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Abstract
General anesthesia serves a critically important function in the clinical care of human patients. However, the anesthetized state has foundational implications for biology because anesthetic drugs are effective in organisms ranging from paramecia, to plants, to primates. Although unconsciousness is typically considered the cardinal feature of general anesthesia, this endpoint is only strictly applicable to a select subset of organisms that are susceptible to being anesthetized. We review the behavioral endpoints of general anesthetics across species and propose the isolation of an organism from its environment - both in terms of the afferent arm of sensation and the efferent arm of action - as a generalizable definition. We also consider the various targets and putative mechanisms of general anesthetics across biology and identify key substrates that are conserved, including cytoskeletal elements, ion channels, mitochondria, and functionally coupled electrical or neural activity. We conclude with a unifying framework related to network function and suggest that general anesthetics - from single cells to complex brains - create inefficiency and enhance modularity, leading to the dissociation of functions both within an organism and between the organism and its surroundings. Collectively, we demonstrate that general anesthesia is not restricted to the domain of modern medicine but has broad biological relevance with wide-ranging implications for a diverse array of species.
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Affiliation(s)
- Max B Kelz
- Department of Anesthesiology and Critical Care, University of Pennsylvania, Perelman School of Medicine, 3620 Hamilton Walk, 334 John Morgan Building, Philadelphia, PA 19104, USA; Center for Sleep and Circadian Neurobiology, University of Pennsylvania, Translational Research Laboratories, 125 S. 31st St., Philadelphia, PA 19104-3403, USA; Mahoney Institute for Neuroscience, University of Pennsylvania, Clinical Research Building, 415 Curie Blvd, Philadelphia, PA 19104, USA.
| | - George A Mashour
- Department of Anesthesiology, University of Michigan, 7433 Medical Science Building 1, 1150 West Medical Center Drive, Ann Arbor, MI 48109, USA; Center for Consciousness Science, University of Michigan Medical School, Ann Arbor, MI 48109, USA; Neuroscience Graduate Program, University of Michigan Medical School, Ann Arbor, MI 48109, USA.
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17
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Kim JJ, Gharpure A, Teng J, Zhuang Y, Howard RJ, Zhu S, Noviello CM, Walsh RM, Lindahl E, Hibbs RE. Shared structural mechanisms of general anaesthetics and benzodiazepines. Nature 2020; 585:303-308. [PMID: 32879488 PMCID: PMC7486282 DOI: 10.1038/s41586-020-2654-5] [Citation(s) in RCA: 164] [Impact Index Per Article: 41.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2019] [Accepted: 06/01/2020] [Indexed: 01/17/2023]
Abstract
Most general anaesthetics and classical benzodiazepine drugs act through positive modulation of γ-aminobutyric acid type A (GABAA) receptors to dampen neuronal activity in the brain1-5. However, direct structural information on the mechanisms of general anaesthetics at their physiological receptor sites is lacking. Here we present cryo-electron microscopy structures of GABAA receptors bound to intravenous anaesthetics, benzodiazepines and inhibitory modulators. These structures were solved in a lipidic environment and are complemented by electrophysiology and molecular dynamics simulations. Structures of GABAA receptors in complex with the anaesthetics phenobarbital, etomidate and propofol reveal both distinct and common transmembrane binding sites, which are shared in part by the benzodiazepine drug diazepam. Structures in which GABAA receptors are bound by benzodiazepine-site ligands identify an additional membrane binding site for diazepam and suggest an allosteric mechanism for anaesthetic reversal by flumazenil. This study provides a foundation for understanding how pharmacologically diverse and clinically essential drugs act through overlapping and distinct mechanisms to potentiate inhibitory signalling in the brain.
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Affiliation(s)
- Jeong Joo Kim
- Department of Neuroscience, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Anant Gharpure
- Department of Neuroscience, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Jinfeng Teng
- Department of Neuroscience, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Yuxuan Zhuang
- Department of Biochemistry and Biophysics, Science for Life Laboratory, Stockholm University, Solna, Sweden
| | - Rebecca J Howard
- Department of Biochemistry and Biophysics, Science for Life Laboratory, Stockholm University, Solna, Sweden
| | - Shaotong Zhu
- Department of Neuroscience, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Colleen M Noviello
- Department of Neuroscience, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Richard M Walsh
- Department of Biological Chemistry and Molecular Pharmacology, Blavatnik Institute, Harvard Medical School, Boston, MA, USA
| | - Erik Lindahl
- Department of Biochemistry and Biophysics, Science for Life Laboratory, Stockholm University, Solna, Sweden
- Department of Applied Physics, Swedish e-Science Research Center, KTH Royal Institute of Technology, Solna, Sweden
| | - Ryan E Hibbs
- Department of Neuroscience, University of Texas Southwestern Medical Center, Dallas, TX, USA.
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18
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Kreuzer M, Butovas S, García PS, Schneider G, Schwarz C, Rudolph U, Antkowiak B, Drexler B. Propofol Affects Cortico-Hippocampal Interactions via β3 Subunit-Containing GABA A Receptors. Int J Mol Sci 2020; 21:ijms21165844. [PMID: 32823959 PMCID: PMC7461501 DOI: 10.3390/ijms21165844] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2020] [Revised: 08/05/2020] [Accepted: 08/07/2020] [Indexed: 11/16/2022] Open
Abstract
BACKGROUND General anesthetics depress neuronal activity. The depression and uncoupling of cortico-hippocampal activity may contribute to anesthetic-induced amnesia. However, the molecular targets involved in this process are not fully characterized. GABAA receptors, especially the type with β3 subunits, represent a main molecular target of propofol. We therefore hypothesized that GABAA receptors with β3 subunits mediate the propofol-induced disturbance of cortico-hippocampal interactions. METHODS We used local field potential (LFP) recordings from chronically implanted cortical and hippocampal electrodes in wild-type and β3(N265M) knock-in mice. In the β3(N265M) mice, the action of propofol via β3subunit containing GABAA receptors is strongly attenuated. The analytical approach contained spectral power, phase locking, and mutual information analyses in the 2-16 Hz range to investigate propofol-induced effects on cortico-hippocampal interactions. RESULTS Propofol caused a significant increase in spectral power between 14 and 16 Hz in the cortex and hippocampus of wild-type mice. This increase was absent in the β3(N265M) mutant. Propofol strongly decreased phase locking of 6-12 Hz oscillations in wild-type mice. This decrease was attenuated in the β3(N265M) mutant. Finally, propofol reduced the mutual information between 6-16 Hz in wild-type mice, but only between 6 and 8 Hz in the β3(N265M) mutant. CONCLUSIONS GABAA receptors containing β3 subunits contribute to frequency-specific perturbation of cortico-hippocampal interactions. This likely explains some of the amnestic actions of propofol.
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Affiliation(s)
- Matthias Kreuzer
- Department of Anesthesiology and Intensive Care, Klinikum rechts der Isar, Technical University of Munich, School of Medicine, Munich, Ismaninger Str. 22, 81675 München, Germany; (M.K.); (G.S.)
| | - Sergejus Butovas
- Werner Reichardt Centre for Integrative Neuroscience, Eberhard-Karls-University, Otfried-Müller-Str. 25, 72076 Tübingen, Germany; (S.B.); (C.S.)
| | - Paul S García
- Department of Anesthesiology, Neuroanesthesia Division, Columbia University Medical Center, New York Presbyterian Hospital, 622 West 168th Street, New York City, NY 10032, USA;
| | - Gerhard Schneider
- Department of Anesthesiology and Intensive Care, Klinikum rechts der Isar, Technical University of Munich, School of Medicine, Munich, Ismaninger Str. 22, 81675 München, Germany; (M.K.); (G.S.)
| | - Cornelius Schwarz
- Werner Reichardt Centre for Integrative Neuroscience, Eberhard-Karls-University, Otfried-Müller-Str. 25, 72076 Tübingen, Germany; (S.B.); (C.S.)
| | - Uwe Rudolph
- Department of Comparative Biosciences, College of Veterinary Medicine, University of Illinois at Urbana-Champaign, 2001 South Lincoln Avenue, Urbana, IL 61802-6178, USA;
- Carl R. Woese Institute for Genomic Biology, University of Illiniois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Bernd Antkowiak
- Department of Anaesthesiology, Experimental Anaesthesiology Section, Eberhard-Karls-University, Waldhörnlestrasse 22, 72072 Tübingen, Germany;
| | - Berthold Drexler
- Department of Anaesthesiology, Experimental Anaesthesiology Section, Eberhard-Karls-University, Waldhörnlestrasse 22, 72072 Tübingen, Germany;
- Correspondence:
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19
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Blednov YA, Borghese CM, Dugan MP, Pradhan S, Thodati TM, Kichili NR, Harris RA, Messing RO. Apremilast regulates acute effects of ethanol and other GABAergic drugs via protein kinase A-dependent signaling. Neuropharmacology 2020; 178:108220. [PMID: 32736086 DOI: 10.1016/j.neuropharm.2020.108220] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2019] [Revised: 06/15/2020] [Accepted: 06/19/2020] [Indexed: 12/19/2022]
Abstract
Phosphodiesterase type 4 (PDE4) inhibitors prevent hydrolysis of cyclic adenosine monophosphate and increase protein kinase A (PKA)-mediated phosphorylation. PDE4 inhibitors also regulate responses to ethanol and GABAergic drugs. We investigated mechanisms by which the PDE4 inhibitor, apremilast, regulates acute effects of ethanol and GABAergic drugs in male and female mice. Apremilast prolonged the sedative-hypnotic effects of gaboxadol, zolpidem, and propofol but did not alter etomidate effects, and unexpectedly shortened the sedative-hypnotic effects of diazepam. Apremilast prolonged rotarod ataxia induced by zolpidem, propofol, and loreclezole, shortened recovery from diazepam, but had no effect on ataxia induced by gaboxadol or etomidate. The PKA inhibitor H-89 blocked apremilast's ability to prolong the sedative-hypnotic effects of ethanol, gaboxadol, and propofol and to prolong ethanol- and propofol-induced ataxia. H-89 also blocked apremilast's ability to shorten the sedative-hypnotic and ataxic effects of diazepam. The β1-specific antagonist, salicylidene salicylhydrazide (SCS), produced faster recovery from ethanol- and diazepam-induced ataxia, but did not alter propofol- or etomidate-induced ataxia. SCS shortened the sedative-hypnotic effects of ethanol and diazepam but not of propofol. In Xenopus oocytes, a phosphomimetic (aspartate) mutation at the PKA phosphorylation site in β1 subunits decreased the maximal GABA current in receptors containing α1 or α3, but not α2 subunits. In contrast, phosphomimetic mutations at PKA sites in β3 subunits increased the maximal GABA current in receptors containing α1 or α2, but not α3 subunits. The GABA potency and allosteric modulation by ethanol, propofol, etomidate, zolpidem, flunitrazepam, or diazepam were not altered by these mutations. We propose a model whereby apremilast increases PKA-mediated phosphorylation of β1-and β3-containing GABAA receptors and selectively alters acute tolerance to ethanol and GABAergic drugs.
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Affiliation(s)
- Yuri A Blednov
- Waggoner Center for Alcohol and Addiction Research, The University of Texas at Austin, Austin, TX, 78712, USA
| | - Cecilia M Borghese
- Waggoner Center for Alcohol and Addiction Research, The University of Texas at Austin, Austin, TX, 78712, USA
| | - Michael P Dugan
- Waggoner Center for Alcohol and Addiction Research, The University of Texas at Austin, Austin, TX, 78712, USA
| | - Swetak Pradhan
- Waggoner Center for Alcohol and Addiction Research, The University of Texas at Austin, Austin, TX, 78712, USA
| | - Thanvi M Thodati
- Waggoner Center for Alcohol and Addiction Research, The University of Texas at Austin, Austin, TX, 78712, USA
| | - Nikhita R Kichili
- Waggoner Center for Alcohol and Addiction Research, The University of Texas at Austin, Austin, TX, 78712, USA
| | - R Adron Harris
- Waggoner Center for Alcohol and Addiction Research, The University of Texas at Austin, Austin, TX, 78712, USA
| | - Robert O Messing
- Waggoner Center for Alcohol and Addiction Research, The University of Texas at Austin, Austin, TX, 78712, USA; Department of Neuroscience, The University of Texas at Austin, Austin, TX, 78712, USA; Department of Neurology, Dell Medical School, The University of Texas at Austin, Austin, TX, 78712, USA.
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20
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A Metabolic Mechanism for Anaesthetic Suppression of Cortical Synaptic Function in Mouse Brain Slices-A Pilot Investigation. Int J Mol Sci 2020; 21:ijms21134703. [PMID: 32630300 PMCID: PMC7370287 DOI: 10.3390/ijms21134703] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2020] [Revised: 06/24/2020] [Accepted: 06/29/2020] [Indexed: 02/07/2023] Open
Abstract
Regulation of synaptically located ionotropic receptors is thought to be the main mechanism by which anaesthetics cause unconsciousness. An alternative explanation, which has received much less attention, is that of primary anaesthetic disruption of brain metabolism via suppression of mitochondrial proteins. In this pilot study in mouse cortical slices, we investigated the effect of disrupting cellular metabolism on tissue oxygen handling and cortical population seizure-like event (SLE) activity, using the mitochondrial complex I inhibitor rotenone, and compared this to the effects of the general anaesthetics sevoflurane, propofol and ketamine. Rotenone caused an increase in tissue oxygen (98 mmHg to 157 mmHg (p < 0.01)) before any measurable change in SLE activity. Thereafter, tissue oxygen continued to increase and was accompanied by a significant and prolonged reduction in SLE root mean square (RMS) activity (baseline RMS of 1.7 to 0.7 µV, p < 0.001) and SLE frequency (baseline 4.2 to 0.4 events/min, p = 0.001). This temporal sequence of effects was replicated by all three anaesthetic drugs. In conclusion, anaesthetics with differing synaptic receptor mechanisms all effect changes in tissue oxygen handling and cortical network activity, consistent with a common inhibitory effect on mitochondrial function. The temporal sequence suggests that the observed synaptic depression—as seen in anaesthesia—may be secondary to a reduction in cellular metabolic capacity.
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21
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Tonon MC, Vaudry H, Chuquet J, Guillebaud F, Fan J, Masmoudi-Kouki O, Vaudry D, Lanfray D, Morin F, Prevot V, Papadopoulos V, Troadec JD, Leprince J. Endozepines and their receptors: Structure, functions and pathophysiological significance. Pharmacol Ther 2020; 208:107386. [DOI: 10.1016/j.pharmthera.2019.06.008] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2019] [Accepted: 06/20/2019] [Indexed: 02/06/2023]
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Drexler B, Seeger T, Worek F, Thiermann H, Antkowiak B, Grasshoff C. Impact of soman and acetylcholine on the effects of propofol in cultured cortical networks. Toxicol Lett 2020; 322:98-103. [PMID: 31954869 DOI: 10.1016/j.toxlet.2020.01.012] [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: 09/30/2019] [Revised: 12/20/2019] [Accepted: 01/15/2020] [Indexed: 11/29/2022]
Abstract
Patients intoxicated with organophosphorous compounds may need general anaesthesia to enable mechanical ventilation or for control of epileptiform seizures. It is well known that cholinergic overstimulation attenuates the efficacy of general anaesthetics to reduce spontaneous network activity in the cortex. However, it is not clear how propofol, the most frequently used intravenous anaesthetic today, is affected. Here, we investigated the effects of cholinergic overstimulation induced by soman and acetylcholine on the ability of propofol to depress spontaneous action potential activity in organotypic cortical slices measured by extracellular voltage recordings. Cholinergic overstimulation by co-application of soman and acetylcholine (10 μM each) did not reduce the relative inhibition of propofol (1.0 μM; mean normalized action potential firing rate 0.49 ± 0.06 of control condition, p < 0.001, Wilcoxon signed rank test) but clearly reduced its efficacy. Co-application of atropine (10 nM) did not improve the efficacy. Propofol preserved its relative inhibitory potential but did not produce a degree of neuronal depression which can be expected to assure hypnosis in humans. Since a combination with atropine did not improve its efficacy, an increase in dosage will probably be necessary when propofol is used in victims suffering from organophosphorous intoxication.
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Affiliation(s)
- Berthold Drexler
- Experimental Anesthesiology Section, Department of Anesthesiology and Intensive Care Medicine, Eberhard-Karls-University, Waldhoernlestrasse 22, 72072, Tuebingen, Germany.
| | - Thomas Seeger
- Bundeswehr Institute of Pharmacology and Toxicology, Neuherbergstrasse 11, 80937, Munich, Germany.
| | - Franz Worek
- Bundeswehr Institute of Pharmacology and Toxicology, Neuherbergstrasse 11, 80937, Munich, Germany.
| | - Horst Thiermann
- Bundeswehr Institute of Pharmacology and Toxicology, Neuherbergstrasse 11, 80937, Munich, Germany.
| | - Bernd Antkowiak
- Experimental Anesthesiology Section, Department of Anesthesiology and Intensive Care Medicine, Eberhard-Karls-University, Waldhoernlestrasse 22, 72072, Tuebingen, Germany; Werner Reichardt Center for Integrative Neuroscience, Eberhard-Karls-University, Tuebingen, Germany.
| | - Christian Grasshoff
- Experimental Anesthesiology Section, Department of Anesthesiology and Intensive Care Medicine, Eberhard-Karls-University, Waldhoernlestrasse 22, 72072, Tuebingen, Germany.
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23
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Belelli D, Hogenkamp D, Gee KW, Lambert JJ. Realising the therapeutic potential of neuroactive steroid modulators of the GABA A receptor. Neurobiol Stress 2019; 12:100207. [PMID: 32435660 PMCID: PMC7231973 DOI: 10.1016/j.ynstr.2019.100207] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2019] [Accepted: 12/19/2019] [Indexed: 01/27/2023] Open
Abstract
In the 1980s particular endogenous metabolites of progesterone and of deoxycorticosterone were revealed to be potent, efficacious, positive allosteric modulators (PAMs) of the GABAA receptor (GABAAR). These reports were followed by the discovery that such steroids may be synthesised not only in peripheral endocrine glands, but locally in the central nervous system (CNS), to potentially act as paracrine, or autocrine "neurosteroid" messengers, thereby fine tuning neuronal inhibition. These discoveries triggered enthusiasm to elucidate the physiological role of such neurosteroids and explore whether their levels may be perturbed in particular psychiatric and neurological disorders. In preclinical studies the GABAAR-active steroids were shown to exhibit anxiolytic, anticonvulsant, analgesic and sedative properties and at relatively high doses to induce a state of general anaesthesia. Collectively, these findings encouraged efforts to investigate the therapeutic potential of neurosteroids and related synthetic analogues. However, following over 30 years of investigation, realising their possible medical potential has proved challenging. The recent FDA approval for the natural neurosteroid allopregnanolone (brexanolone) to treat postpartum depression (PPD) should trigger renewed enthusiasm for neurosteroid research. Here we focus on the influence of neuroactive steroids on GABA-ergic signalling and on the challenges faced in developing such steroids as anaesthetics, sedatives, analgesics, anticonvulsants, antidepressants and as treatments for neurodegenerative disorders.
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Affiliation(s)
- Delia Belelli
- Systems Medicine, Neuroscience, Mail Box 6, University of Dundee, Ninewells Hospital and Medical School, Dundee, DD1 9SY, United Kingdom
| | - Derk Hogenkamp
- Department of Pharmacology, 110C Med Surge1, Mail Code 4625, University of California, Irvine, School of Medicine, Irvine, CA, 92697, USA
| | - Kelvin W Gee
- Department of Pharmacology, 110C Med Surge1, Mail Code 4625, University of California, Irvine, School of Medicine, Irvine, CA, 92697, USA
| | - Jeremy J Lambert
- Systems Medicine, Neuroscience, Mail Box 6, University of Dundee, Ninewells Hospital and Medical School, Dundee, DD1 9SY, United Kingdom
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The Locus Coeruleus Modulates Intravenous General Anesthesia of Zebrafish via a Cooperative Mechanism. Cell Rep 2019; 24:3146-3155.e3. [PMID: 30231998 DOI: 10.1016/j.celrep.2018.08.046] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2018] [Revised: 06/17/2018] [Accepted: 08/16/2018] [Indexed: 01/03/2023] Open
Abstract
How general anesthesia causes loss of consciousness has been a mystery for decades. It is generally thought that arousal-related brain nuclei, including the locus coeruleus (LC), are involved. Here, by monitoring locomotion behaviors and neural activities, we developed a larval zebrafish model for studying general anesthesia induced by propofol and etomidate, two commonly used intravenous anesthetics. Local lesion of LC neurons via two-photon laser-based ablation or genetic depletion of norepinephrine (NE; a neuromodulator released by LC neurons) via CRISPR/Cas9-based mutation of dopamine-β-hydroxylase (dbh) accelerates induction into and retards emergence from general anesthesia. Mechanistically, in vivo whole-cell recording revealed that both anesthetics suppress LC neurons' activity through a cooperative mechanism, inhibiting presynaptic excitatory inputs and inducing GABAA receptor-mediated hyperpolarization of these neurons. Thus, our study indicates that the LC-NE system plays a modulatory role in both induction of and emergence from intravenous general anesthesia.
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25
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Rossokhin AV, Sharonova IN, Dvorzhak A, Bukanova JV, Skrebitsky VG. The mechanisms of potentiation and inhibition of GABA A receptors by non-steroidal anti-inflammatory drugs, mefenamic and niflumic acids. Neuropharmacology 2019; 160:107795. [PMID: 31560908 DOI: 10.1016/j.neuropharm.2019.107795] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2019] [Revised: 09/02/2019] [Accepted: 09/23/2019] [Indexed: 11/27/2022]
Abstract
Fenamates mefanamic and niflumic acids (MFA and NFA) induced dual potentiating and inhibitory effects on GABA currents recorded in isolated cerebellar Purkinje cells using the whole-cell patch-clamp and fast-application techniques. Regardless of the concentration, both drugs induced a pronounced prolongation of the current response. We demonstrated that the same concentration of drugs can produce both potentiating and inhibitory effects, depending on the GABA concentration, which indicates that both processes take place simultaneously and the net effect depends on the concentrations of both the agonist and fenamate. We found that the NFA-induced block is strongly voltage-dependent. The Woodhull analysis of the block suggests that NFA has two binding sites in the pore - shallow and deep. We built a homology model of the open GABAAR based on the cryo-EM structure of the open α1 GlyR and applied Monte-Carlo energy minimization to optimize the ligand-receptor complexes. A systematic search for MFA/NFA binding sites in the GABAAR pore revealed the existence of two sites, the location of which coincides well with predictions of the Woodhull model. In silico docking suggests that two fenamate molecules are necessary to occlude the pore. We showed that MFA, acting as a PAM, competes with an intravenous anesthetic etomidate for a common binding site. We built structural models of MFA and NFA binding at the transmembrane β(+)/α(-) intersubunit interface. We suggested a hypothesis on the molecular mechanism underlying the prolongation of the receptor lifetime in open state after MFA/NFA binding and β subunit specificity of the fenamate potentiation.
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Affiliation(s)
| | | | - Anton Dvorzhak
- Charité-Universitätsmedizin, Neuroscience Research Center, Berlin, Germany
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26
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Moniri NH. Reintroduction of quazepam: an update on comparative hypnotic and adverse effects. Int Clin Psychopharmacol 2019; 34:275-285. [PMID: 31274695 DOI: 10.1097/yic.0000000000000277] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Insomnia is a prevalent disorder that affects over one-third of the U.S. population to varying degrees and is highly disruptive towards quality of life. Pharmacological treatments for insomnia include benzodiazepines (BZs) and the non-BZ 'Z-drugs' (zolpidem, zaleplon, eszopiclone, zopiclone), which are amongst the most widely prescribed medications. Yet, these agents can produce adverse effects such as tolerance to the hypnotic effect, rebound insomnia, next-day residual drowsiness, as well as amnesia and complex behaviours such as sleep-walking, sleep-eating and sleep-driving. Quazepam, one of the five BZ approved for treatment of insomnia, was recently relaunched to the U.S. market in 2016 and is distinguished amongst hypnotic BZ by unique pharmacological characteristics including selectivity for sleep-promoting α1-subunit containing γ-aminobutyric acid (GABA-A) receptors and a significantly lower relative receptor binding affinity. These features likely drive the decreased rate of adverse events seen clinically with quazepam, such as tolerance, rebound insomnia and amnesic behaviours, compared with other BZ. Given the recent reintroduction of quazepam as a pharmacotherapeutic option, and the lack of head-to-head comparative trials against newer agents, the purpose of this review is to provide an update on distinguishing features of quazepam with regard to its pharmacology, pharmacokinetics, sleep efficacy and potential adverse effects compared to other agents used for insomnia.
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Affiliation(s)
- Nader H Moniri
- Department of Pharmaceutical Sciences, College of Pharmacy, Mercer University Health Sciences Center, Mercer University, Atlanta, Georgia, USA
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27
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Abstract
Current GABAergic sleep-promoting medications were developed pragmatically, without making use of the immense diversity of GABAA receptors. Pharmacogenetic experiments are leading to an understanding of the circuit mechanisms in the hypothalamus by which zolpidem and similar compounds induce sleep at α2βγ2-type GABAA receptors. Drugs acting at more selective receptor types, for example, at receptors containing the α2 and/or α3 subunits expressed in hypothalamic and brain stem areas, could in principle be useful as hypnotics/anxiolytics. A highly promising sleep-promoting drug, gaboxadol, which activates αβδ-type receptors failed in clinical trials. Thus, for the time being, drugs such as zolpidem, which work as positive allosteric modulators at GABAA receptors, continue to be some of the most effective compounds to treat primary insomnia.
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Affiliation(s)
- W Wisden
- Department Life Sciences, Imperial College London, London, SW7 2AZ, UK.
| | - X Yu
- Department Life Sciences, Imperial College London, London, SW7 2AZ, UK
| | - N P Franks
- Department Life Sciences, Imperial College London, London, SW7 2AZ, UK
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28
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Furukawa T, Nikaido Y, Shimoyama S, Ogata Y, Kushikata T, Hirota K, Kanematsu T, Hirata M, Ueno S. Phospholipase C-related inactive protein type-1 deficiency affects anesthetic electroencephalogram activity induced by propofol and etomidate in mice. J Anesth 2019; 33:531-542. [PMID: 31332527 DOI: 10.1007/s00540-019-02663-z] [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: 03/03/2019] [Accepted: 07/08/2019] [Indexed: 11/25/2022]
Abstract
PURPOSE The general anesthetics propofol and etomidate mainly exert their anesthetic actions via GABA A receptor (GABAA-R). The GABAA-R activity is influenced by phospholipase C-related inactive protein type-1 (PRIP-1), which is related to trafficking and subcellular localization of GABAA-R. PRIP-1 deficiency attenuates the behavioral reactions to propofol but not etomidate. However, the effect of these anesthetics and of PRIP-1 deficiency on brain activity of CNS are still unclear. In this study, we examined the effects of propofol and etomidate on the electroencephalogram (EEG). METHODS The cortical EEG activity was recorded in wild-type (WT) and PRIP-1 knockout (PRIP-1 KO) mice. All recorded EEG data were offline analyzed, and the power spectral density and 95% spectral edge frequency of EEG signals were compared between genotypes before and after injections of anesthetics. RESULTS PRIP-1 deficiency induced increases in EEG absolute powers, but did not markedly change the relative spectral powers during waking and sleep states in the absence of anesthesia. Propofol administration induced increases in low-frequency relative EEG activity and decreases in SEF95 values in WT but not in PRIP-1 KO mice. Following etomidate injection, low-frequency EEG power was increased in both genotype groups. At high frequency, the relative power in PRIP-1 KO mice was smaller than that in WT mice. CONCLUSIONS The lack of PRIP-1 disrupted the EEG power distribution, but did not affect the depth of anesthesia after etomidate administration. Our analyses suggest that PRIP-1 is differentially involved in anesthetic EEG activity with the regulation of GABAA-R activity.
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Affiliation(s)
- Tomonori Furukawa
- Department of Neurophysiology, Hirosaki University Graduate School of Medicine, 5 Zaihu-cho, Hirosaki, Aomori, 036-8562, Japan
| | - Yoshikazu Nikaido
- Department of Neurophysiology, Hirosaki University Graduate School of Medicine, 5 Zaihu-cho, Hirosaki, Aomori, 036-8562, Japan.,Department of Anesthesiology, Hirosaki University Graduate School of Medicine, Hirosaki, Japan
| | - Shuji Shimoyama
- Department of Neurophysiology, Hirosaki University Graduate School of Medicine, 5 Zaihu-cho, Hirosaki, Aomori, 036-8562, Japan
| | - Yoshiki Ogata
- Department of Neurophysiology, Hirosaki University Graduate School of Medicine, 5 Zaihu-cho, Hirosaki, Aomori, 036-8562, Japan
| | - Tetsuya Kushikata
- Department of Anesthesiology, Hirosaki University Graduate School of Medicine, Hirosaki, Japan
| | - Kazuyoshi Hirota
- Department of Anesthesiology, Hirosaki University Graduate School of Medicine, Hirosaki, Japan
| | - Takashi Kanematsu
- Department of Cellular and Molecular Pharmacology, Division of Basic Life Sciences, Institute of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan
| | - Masato Hirata
- School of Dental Medicine, Fukuoka Dental College, Fukuoka, Japan
| | - Shinya Ueno
- Department of Neurophysiology, Hirosaki University Graduate School of Medicine, 5 Zaihu-cho, Hirosaki, Aomori, 036-8562, Japan. .,Research Center for Child Mental Development, Hirosaki University Graduate School of Medicine, Hirosaki, Japan.
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29
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Antkowiak B, Rammes G. GABA(A) receptor-targeted drug development -New perspectives in perioperative anesthesia. Expert Opin Drug Discov 2019; 14:683-699. [DOI: 10.1080/17460441.2019.1599356] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Affiliation(s)
- Bernd Antkowiak
- Department of Anesthesiology and Intensive Care, Experimental Anesthesiology Section, Eberhard-Karls-University,
Tübingen, Germany
- Department of Anaesthesiology and Intensive Care, Experimental Anaesthesiology Section, Werner Reichardt Center for Integrative Neuroscience, Tübingen,
Germany
| | - Gerhard Rammes
- University Hospital rechts der Isar, Department of Anesthesiology, München,
Germany
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30
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Lischik CQ, Adelmann L, Wittbrodt J. Enhanced in vivo-imaging in medaka by optimized anaesthesia, fluorescent protein selection and removal of pigmentation. PLoS One 2019; 14:e0212956. [PMID: 30845151 PMCID: PMC6405165 DOI: 10.1371/journal.pone.0212956] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2018] [Accepted: 02/12/2019] [Indexed: 02/07/2023] Open
Abstract
Fish are ideally suited for in vivo-imaging due to their transparency at early stages combined with a large genetic toolbox. Key challenges to further advance imaging are fluorophore selection, immobilization of the specimen and approaches to eliminate pigmentation. We addressed all three and identified the fluorophores and anaesthesia of choice by high throughput time-lapse imaging. Our results indicate that eGFP and mCherry are the best conservative choices for in vivo-fluorescence experiments, when availability of well-established antibodies and nanobodies matters. Still, mVenusNB and mGFPmut2 delivered highest absolute fluorescence intensities in vivo. Immobilization is of key importance during extended in vivo imaging. Here, traditional approaches are outperformed by mRNA injection of α-Bungarotoxin which allows a complete and reversible, transient immobilization. In combination with fully transparent juvenile and adult fish established by the targeted inactivation of both, oca2 and pnp4a via CRISPR/Cas9-mediated gene editing in medaka we could dramatically improve the state-of-the art imaging conditions in post-embryonic fish, now enabling light-sheet microscopy of the growing retina, brain, gills and inner organs in the absence of side effects caused by anaesthetic drugs or pigmentation.
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Affiliation(s)
- Colin Q Lischik
- Centre for Organismal Studies (COS) Heidelberg, Heidelberg University, Heidelberg, Germany.,Heidelberg Biosciences International Graduate School, Heidelberg University, Heidelberg, Germany
| | - Leonie Adelmann
- Centre for Organismal Studies (COS) Heidelberg, Heidelberg University, Heidelberg, Germany
| | - Joachim Wittbrodt
- Centre for Organismal Studies (COS) Heidelberg, Heidelberg University, Heidelberg, Germany
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31
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Weir CJ, Mitchell SJ, Lambert JJ. Role of GABAA receptor subtypes in the behavioural effects of intravenous general anaesthetics. Br J Anaesth 2019; 119:i167-i175. [PMID: 29161398 DOI: 10.1093/bja/aex369] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Since the introduction of general anaesthetics into clinical practice, researchers have been mystified as to how these chemically disparate drugs act to produce their dramatic effects on central nervous system function and behaviour. Scientific advances, particularly during the last 25 years, have now begun to reveal the molecular mechanisms underpinning their behavioural effects. For certain i.v. general anaesthetics, such as etomidate and propofol, a persuasive case can now be made that the GABAA receptor, a major inhibitory receptor in the mammalian central nervous system, is an important target. Advances in molecular pharmacology and in genetic manipulation of rodent genes reveal that different subtypes of the GABAA receptor are responsible for mediating particular aspects of the anaesthetic behavioural repertoire. Such studies provide a better understanding of the neuronal circuitry involved in the various anaesthetic-induced behaviours and, in the future, may result in the development of novel therapeutics with a reduced propensity for side-effects.
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Affiliation(s)
- C J Weir
- Institute of Academic Anaesthesia
| | - S J Mitchell
- Division of Neuroscience, Ninewells Hospital and Medical School, University of Dundee, Dundee, UK
| | - J J Lambert
- Division of Neuroscience, Ninewells Hospital and Medical School, University of Dundee, Dundee, UK
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32
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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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33
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Optimising the transient expression of GABA(A) receptors in adherent HEK293 cells. Protein Expr Purif 2018; 154:7-15. [PMID: 30248449 DOI: 10.1016/j.pep.2018.09.012] [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: 06/22/2018] [Revised: 09/17/2018] [Accepted: 09/20/2018] [Indexed: 11/22/2022]
Abstract
Owing to their therapeutic relevance, considerable efforts are devoted to the structural characterisation of membrane proteins. Such studies are limited by the availability of high quality protein due to the difficulty of overexpression in recombinant mammalian systems. We sought to systematically optimise multiple aspects in the process of transiently transfecting HEK293 cells, to allow the rapid expression of membrane proteins, without the lengthy process of stable clone formation. We assessed the impact of medium formulation, cell line, and harvest time on the expression of GABAA receptors, as determined by [3H]muscimol binding in cell membranes. Furthermore, transfection with the use of calcium phosphate/polyethyleneimine multishell nanoparticles was optimised, and a dual vector system utilising viral enhancing elements was designed and implemented. These efforts resulted in a 40-fold improvement in GABAA α1β3 receptor expression, providing final yields of 22 fmol/cm2. The findings from this work provide a guide to the optimisation of transient expression of proteins in mammalian cells and should assist in the structural characterisation of membrane proteins.
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34
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Enhanced GABAergic actions resulting from the coapplication of the steroid 3α-hydroxy-5α-pregnane-11,20-dione (alfaxalone) with propofol or diazepam. Sci Rep 2018; 8:10341. [PMID: 29985445 PMCID: PMC6037692 DOI: 10.1038/s41598-018-28754-7] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2018] [Accepted: 06/29/2018] [Indexed: 11/09/2022] Open
Abstract
Many GABAergic drugs are in clinical use as anesthetics, sedatives, or anxiolytics. We have investigated the actions of the combinations of the neuroactive steroid 3α-hydroxy-5α-pregnane-11,20-dione (alfaxalone) with the intravenous anesthetic propofol or the benzodiazepine diazepam. The goal of the study was to determine whether coapplication of alfaxalone reduces the effective doses and concentrations of propofol and diazepam. Behavioral effects of alfaxalone, propofol, diazepam, and the combinations of the drugs were evaluated during a 30-min activity test in mice. Functional effects of the individual drugs and drug combinations were tested by measuring the decay times of spontaneous inhibitory postsynaptic currents in rat hippocampal neurons, and peak current responses from heterologously expressed concatemeric α1β2γ2L GABAA receptors. Co-administration of alfaxalone increased the sedative actions of propofol and diazepam in mice. The combination of alfaxalone with propofol or diazepam increased the decay times of sIPSCs and shifted the concentration-response relationships for GABA-activated receptors to lower transmitter concentrations. We infer that alfaxalone acts as a co-agonist to enhance the GABAergic effects of propofol and diazepam. We propose that co-administration of alfaxalone, and possibly other neuroactive steroids, can be employed to reduce dosage requirements for propofol and diazepam.
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35
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Olsen RW. GABA A receptor: Positive and negative allosteric modulators. Neuropharmacology 2018; 136:10-22. [PMID: 29407219 PMCID: PMC6027637 DOI: 10.1016/j.neuropharm.2018.01.036] [Citation(s) in RCA: 189] [Impact Index Per Article: 31.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2017] [Revised: 01/23/2018] [Accepted: 01/25/2018] [Indexed: 12/11/2022]
Abstract
gamma-Aminobutyric acid (GABA)-mediated inhibitory neurotransmission and the gene products involved were discovered during the mid-twentieth century. Historically, myriad existing nervous system drugs act as positive and negative allosteric modulators of these proteins, making GABA a major component of modern neuropharmacology, and suggesting that many potential drugs will be found that share these targets. Although some of these drugs act on proteins involved in synthesis, degradation, and membrane transport of GABA, the GABA receptors Type A (GABAAR) and Type B (GABABR) are the targets of the great majority of GABAergic drugs. This discovery is due in no small part to Professor Norman Bowery. Whereas the topic of GABABR is appropriately emphasized in this special issue, Norman Bowery also made many insights into GABAAR pharmacology, the topic of this article. GABAAR are members of the ligand-gated ion channel receptor superfamily, a chloride channel family of a dozen or more heteropentameric subtypes containing 19 possible different subunits. These subtypes show different brain regional and subcellular localization, age-dependent expression, and potential for plastic changes with experience including drug exposure. Not only are GABAAR the targets of agonist depressants and antagonist convulsants, but most GABAAR drugs act at other (allosteric) binding sites on the GABAAR proteins. Some anxiolytic and sedative drugs, like benzodiazepine and related drugs, act on GABAAR subtype-dependent extracellular domain sites. General anesthetics including alcohols and neurosteroids act at GABAAR subunit-interface trans-membrane sites. Ethanol at high anesthetic doses acts on GABAAR subtype-dependent trans-membrane domain sites. Ethanol at low intoxicating doses acts at GABAAR subtype-dependent extracellular domain sites. Thus GABAAR subtypes possess pharmacologically specific receptor binding sites for a large group of different chemical classes of clinically important neuropharmacological agents. This article is part of the "Special Issue Dedicated to Norman G. Bowery".
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Affiliation(s)
- Richard W Olsen
- Department of Molecular & Medical Pharmacology, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA.
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36
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Wasilczuk AZ, Maier KL, Kelz MB. The Mouse as a Model Organism for Assessing Anesthetic Sensitivity. Methods Enzymol 2018; 602:211-228. [PMID: 29588030 DOI: 10.1016/bs.mie.2018.01.008] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
The mouse has been used in many medical fields as a powerful model to reveal the genetic basis of human physiology and disease. The past two decades have witnessed an enormous wealth of genetic and informatic resources dedicated to this humble organism. With the ongoing revolution in mapping neural circuitry governing behavior, the mouse is an ideal model organism poised to unravel the mysteries of general anesthetic action. This chapter will describe and provide guidelines for anesthetic phenotyping in the mouse including both motor-dependent and motor-independent assessments.
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Affiliation(s)
- Andrzej Z Wasilczuk
- University of Pennsylvania, Perelman School of Medicine, Philadelphia, PA, United States
| | - Kaitlyn L Maier
- University of Pennsylvania, Perelman School of Medicine, Philadelphia, PA, United States
| | - Max B Kelz
- University of Pennsylvania, Perelman School of Medicine, Philadelphia, PA, United States; Center for Sleep and Circadian Neurobiology, University of Pennsylvania, Perelman School of Medicine, Philadelphia, PA, United States.
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37
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Antkowiak B, Rudolph U. New insights in the systemic and molecular underpinnings of general anesthetic actions mediated by γ-aminobutyric acid A receptors. Curr Opin Anaesthesiol 2018; 29:447-53. [PMID: 27168087 DOI: 10.1097/aco.0000000000000358] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
PURPOSE OF REVIEW The review highlights novel insights into the role of γ-aminobutyric acid A (GABAA) receptors in mediating clinically relevant actions of anesthetic agents. RECENT FINDINGS GABAA receptors in the hippocampus are located on glutamatergic pyramidal cells and GABAergic interneurons. Etomidate-induced inhibition of a synaptic correlate of learning and memory is caused by receptors on nonpyramidal neurons, likely on interneurons that incorporate α5 subunits. Selective enhancement of α2 subunit containing GABAA receptors in the spinal cord provides antihyperalgesia against inflammatory and neuropathic pain without causing sedation, motor impairment, and tolerance development. Inflammation, traumatic brain injury, and exposure to anesthetic agents modify the expression patterns of GABAA receptors in a subtype-specific manner. These modifications may persist for weeks. The neuroactive steroid alphaxalone causes fast-onset and short-duration anesthesia in humans. Cardiovascular and respiratory side-effects are less severe than with propofol. SUMMARY Identification of the molecular and cellular substrates involved in anesthesia and insights into disease and drug-induced alterations in the expression patterns of GABAA receptors in the central nervous system are emphasizing the need for individualized anesthesia care. Introducing neuroactive steroids into clinical anesthesia is expected to reduce cardiovascular and respiratory side-effects.
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Affiliation(s)
- Bernd Antkowiak
- aDepartment of Anesthesiology and Intensive Care, Experimental Anesthesiology Section bWerner Reichardt Center for Integrative Neuroscience, Eberhard-Karls-University, Tübingen, Germany cLaboratory of Genetic Neuropharmacology, McLean Hospital, Belmont dDepartment of Psychiatry, Harvard Medical School, Boston, Massachusetts, USA
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38
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Gelegen C, Miracca G, Ran MZ, Harding EC, Ye Z, Yu X, Tossell K, Houston CM, Yustos R, Hawkins ED, Vyssotski AL, Dong HL, Wisden W, Franks NP. Excitatory Pathways from the Lateral Habenula Enable Propofol-Induced Sedation. Curr Biol 2018; 28:580-587.e5. [PMID: 29398217 PMCID: PMC5835141 DOI: 10.1016/j.cub.2017.12.050] [Citation(s) in RCA: 49] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2017] [Revised: 12/12/2017] [Accepted: 12/21/2017] [Indexed: 12/30/2022]
Abstract
The lateral habenula has been widely studied for its contribution in generating reward-related behaviors [1, 2]. We have found that this nucleus plays an unexpected role in the sedative actions of the general anesthetic propofol. The lateral habenula is a glutamatergic, excitatory hub that projects to multiple targets throughout the brain, including GABAergic and aminergic nuclei that control arousal [3-5]. When glutamate release from the lateral habenula in mice was genetically blocked, the ability of propofol to induce sedation was greatly diminished. In addition to this reduced sensitivity to propofol, blocking output from the lateral habenula caused natural non-rapid eye movement (NREM) sleep to become highly fragmented, especially during the rest ("lights on") period. This fragmentation was largely reversed by the dual orexinergic antagonist almorexant. We conclude that the glutamatergic output from the lateral habenula is permissive for the sedative actions of propofol and is also necessary for the consolidation of natural sleep.
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Affiliation(s)
- Cigdem Gelegen
- Department of Life Sciences, Imperial College London, South Kensington SW7 2AZ, UK
| | - Giulia Miracca
- Department of Life Sciences, Imperial College London, South Kensington SW7 2AZ, UK
| | - Mingzi Z Ran
- Department of Anesthesiology & Perioperative Medicine, Xijing Hospital, Xi'an, Shaanxi 710032, China
| | - Edward C Harding
- Department of Life Sciences, Imperial College London, South Kensington SW7 2AZ, UK
| | - Zhiwen Ye
- Department of Life Sciences, Imperial College London, South Kensington SW7 2AZ, UK
| | - Xiao Yu
- Department of Life Sciences, Imperial College London, South Kensington SW7 2AZ, UK
| | - Kyoko Tossell
- Department of Life Sciences, Imperial College London, South Kensington SW7 2AZ, UK
| | - Catriona M Houston
- Department of Life Sciences, Imperial College London, South Kensington SW7 2AZ, UK
| | - Raquel Yustos
- Department of Life Sciences, Imperial College London, South Kensington SW7 2AZ, UK
| | - Edwin D Hawkins
- Department of Life Sciences, Imperial College London, South Kensington SW7 2AZ, UK
| | - Alexei L Vyssotski
- Institute of Neuroinformatics, University of Zürich/ETH Zürich, Winterthurerstrasse 190, 8057 Zürich, Switzerland
| | - Hailong L Dong
- Department of Anesthesiology & Perioperative Medicine, Xijing Hospital, Xi'an, Shaanxi 710032, China
| | - William Wisden
- Department of Life Sciences, Imperial College London, South Kensington SW7 2AZ, UK; Centre of Excellence in Neurotechnology and UK Dementia Research Institute, Imperial College London, South Kensington SW7 2AZ, UK.
| | - Nicholas P Franks
- Department of Life Sciences, Imperial College London, South Kensington SW7 2AZ, UK; Centre of Excellence in Neurotechnology and UK Dementia Research Institute, Imperial College London, South Kensington SW7 2AZ, UK.
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Yu X, Franks NP, Wisden W. Sleep and Sedative States Induced by Targeting the Histamine and Noradrenergic Systems. Front Neural Circuits 2018; 12:4. [PMID: 29434539 PMCID: PMC5790777 DOI: 10.3389/fncir.2018.00004] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2017] [Accepted: 01/11/2018] [Indexed: 01/07/2023] Open
Abstract
Sedatives target just a handful of receptors and ion channels. But we have no satisfying explanation for how activating these receptors produces sedation. In particular, do sedatives act at restricted brain locations and circuitries or more widely? Two prominent sedative drugs in clinical use are zolpidem, a GABAA receptor positive allosteric modulator, and dexmedetomidine (DEX), a selective α2 adrenergic receptor agonist. By targeting hypothalamic neuromodulatory systems both drugs induce a sleep-like state, but in different ways: zolpidem primarily reduces the latency to NREM sleep, and is a controlled substance taken by many people to help them sleep; DEX produces prominent slow wave activity in the electroencephalogram (EEG) resembling stage 2 NREM sleep, but with complications of hypothermia and lowered blood pressure—it is used for long term sedation in hospital intensive care units—under DEX-induced sedation patients are arousable and responsive, and this drug reduces the risk of delirium. DEX, and another α2 adrenergic agonist xylazine, are also widely used in veterinary clinics to sedate animals. Here we review how these two different classes of sedatives, zolpidem and dexmedetomideine, can selectively interact with some nodal points of the circuitry that promote wakefulness allowing the transition to NREM sleep. Zolpidem enhances GABAergic transmission onto histamine neurons in the hypothalamic tuberomammillary nucleus (TMN) to hasten the transition to NREM sleep, and DEX interacts with neurons in the preoptic hypothalamic area that induce sleep and body cooling. This knowledge may aid the design of more precise acting sedatives, and at the same time, reveal more about the natural sleep-wake circuitry.
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Affiliation(s)
- Xiao Yu
- Department of Life Sciences, Imperial College London, London, United Kingdom
| | - Nicholas P Franks
- Department of Life Sciences, Imperial College London, London, United Kingdom.,Centre for Neurotechnology, Imperial College London, London, United Kingdom.,UK Dementia Research Institute, Imperial College London, London, United Kingdom
| | - William Wisden
- Department of Life Sciences, Imperial College London, London, United Kingdom.,Centre for Neurotechnology, Imperial College London, London, United Kingdom.,UK Dementia Research Institute, Imperial College London, London, United Kingdom
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Kishikawa JI, Inoue Y, Fujikawa M, Nishimura K, Nakanishi A, Tanabe T, Imamura H, Yokoyama K. General anesthetics cause mitochondrial dysfunction and reduction of intracellular ATP levels. PLoS One 2018; 13:e0190213. [PMID: 29298324 PMCID: PMC5752027 DOI: 10.1371/journal.pone.0190213] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2017] [Accepted: 12/11/2017] [Indexed: 12/29/2022] Open
Abstract
General anesthetics are indispensable for effective clinical care. Although, the mechanism of action of general anesthetics remains controversial, lipid bilayers and proteins have been discussed as their targets. In this study, we focused on the relationship between cellular ATP levels and general anesthetics. The ATP levels of nematodes and cultured mammalian cells were decreased by exposure to three general anesthetics: isoflurane, pentobarbital, and 1-phenoxy-2-propanol. Furthermore, these general anesthetics abolished mitochondrial membrane potential, resulting in the inhibition of mitochondrial ATP synthesis. These results suggest that the observed decrease of cellular ATP level is a common phenomenon of general anesthetics.
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Affiliation(s)
- Jun-ichi Kishikawa
- Department of Molecular Biosciences, Faculty of Life Sciences, Kyoto Sangyo University, Kamigamo-Motoyama, Kita-ku, Kyoto, Japan
| | - Yuki Inoue
- Department of Molecular Biosciences, Faculty of Life Sciences, Kyoto Sangyo University, Kamigamo-Motoyama, Kita-ku, Kyoto, Japan
| | - Makoto Fujikawa
- Departmet of Pharmacology Neurobiology, Graduate School of Medicine, Tokyo Medical and Dental University, Bunkyo-ku, Tokyo, Japan
| | - Kenji Nishimura
- Department of Molecular Biosciences, Faculty of Life Sciences, Kyoto Sangyo University, Kamigamo-Motoyama, Kita-ku, Kyoto, Japan
| | - Atsuko Nakanishi
- Department of Molecular Biosciences, Faculty of Life Sciences, Kyoto Sangyo University, Kamigamo-Motoyama, Kita-ku, Kyoto, Japan
| | - Tsutomu Tanabe
- Departmet of Pharmacology Neurobiology, Graduate School of Medicine, Tokyo Medical and Dental University, Bunkyo-ku, Tokyo, Japan
| | - Hiromi Imamura
- Graduate School of Biostudies, Kyoto University, Yoshida-konoe-cho, Sakyo-ku, Kyoto, Japan
- * E-mail: (HI); (KY)
| | - Ken Yokoyama
- Department of Molecular Biosciences, Faculty of Life Sciences, Kyoto Sangyo University, Kamigamo-Motoyama, Kita-ku, Kyoto, Japan
- * E-mail: (HI); (KY)
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Sahin S, Eulenburg V, Heinlein A, Villmann C, Pischetsrieder M. Identification of eugenol as the major determinant of GABAA-receptor activation by aqueous Syzygium aromaticum L. (clove buds) extract. J Funct Foods 2017. [DOI: 10.1016/j.jff.2017.08.033] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
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GABA A receptor subunit gene polymorphisms predict symptom-based and developmental deficits in Chinese Han children and adolescents with autistic spectrum disorders. Sci Rep 2017; 7:3290. [PMID: 28607477 PMCID: PMC5468250 DOI: 10.1038/s41598-017-03666-0] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2017] [Accepted: 05/02/2017] [Indexed: 12/29/2022] Open
Abstract
GABAA receptor subunit genes GABRB3, GABRA5, and GABRG3 located on chromosome 15q11-q13 have been implicated in the etiology of autistic spectrum disorders (ASD). This study intended to investigate the possible role of single-nucleotide polymorphisms (SNPs) present in GABRB3 (rs2081648 and rs1426217), GABRA5 (rs35586628), and GABRG3 (rs208129) genes in ASD susceptibility and symptom-based and developmental phenotypes of ASD in Chinese Han children and adolescents. 99 ASD patients and 231 age- and gender- frequency-matched typical developing (TD) controls were tested by TaqMan® genotyping assay. Symptom-based phenotypes were evaluated by Childhood Autism Rating Scale (CARS) and Autism Behavior Checklist (ABC), and developmental phenotypes were assessed by Early Childhood Development Questionnaire (ECDQ) in ASD patients. Three haplotypes and global χ 2 test of all SNPs demonstrated significant associations between ASD and TD groups. Besides, GABRB3 rs2081648, GABRA5 rs35586628, and GABRG3 rs208129 polymorphisms were associated with symptom-based deficits in social interaction, sensorimotor and somatosensory coordination, visual response, imitation, activity level, language expression and adaptability. Developmental abnormalities in late emergences of social interaction and fine motor were detected in GABRB3 rs2081648 polymorphism. Overall results indicated that gene synergy may participate in ASD pathogenesis, and GABAA receptor gene polymorphisms can predict symptom-based and developmental deficits in ASD individuals.
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Nikaido Y, Furukawa T, Shimoyama S, Yamada J, Migita K, Koga K, Kushikata T, Hirota K, Kanematsu T, Hirata M, Ueno S. Propofol Anesthesia Is Reduced in Phospholipase C-Related Inactive Protein Type-1 Knockout Mice. J Pharmacol Exp Ther 2017; 361:367-374. [PMID: 28404686 DOI: 10.1124/jpet.116.239145] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2016] [Accepted: 04/04/2017] [Indexed: 11/22/2022] Open
Abstract
The GABA type A receptor (GABAA-R) is a major target of intravenous anesthetics. Phospholipase C-related inactive protein type-1 (PRIP-1) is important in GABAA-R phosphorylation and membrane trafficking. In this study, we investigated the role of PRIP-1 in general anesthetic action. The anesthetic effects of propofol, etomidate, and pentobarbital were evaluated in wild-type and PRIP-1 knockout (PRIP-1 KO) mice by measuring the latency and duration of loss of righting reflex (LORR) and loss of tail-pinch withdrawal response (LTWR). The effect of pretreatment with okadaic acid (OA), a protein phosphatase 1/2A inhibitor, on propofol- and etomidate-induced LORR was also examined. PRIP-1 deficiency provided the reduction of LORR and LTWR induced by propofol but not by etomidate or pentobarbital, indicating that PRIP-1 could determine the potency of the anesthetic action of propofol. Pretreatment with OA recovered the anesthetic potency induced by propofol in PRIP-1 KO mice. OA injection enhanced phosphorylation of cortical the GABAA-R β3 subunit in PRIP-1 KO mice. These results suggest that PRIP-1-mediated GABAA-R β3 subunit phosphorylation might be involved in the general anesthetic action induced by propofol but not by etomidate or pentobarbital.
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Affiliation(s)
- Yoshikazu Nikaido
- Graduate School of Medicine (Y.N.), Department of Neurophysiology (Y.N., T.F., K.K., S.U.) and Department of Anesthesiology, Graduate School of Medicine (Y.N., T.Ku., K.H.), Research Center for Child Mental Development, Graduate School of Medicine (S.S., S.U.), and Department of Biomedical Sciences, Division of Medical Life Sciences, Graduate School of Health Sciences (J.Y.), Hirosaki University, Hirosaki, Japan; Department of Drug Informatics, Faculty of Pharmaceutical Sciences, Fukuoka University, Fukuoka, Japan (K.M.); Department of Cellular and Molecular Pharmacology, Division of Basic Life Sciences, Institute of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan (T.Ka.); Laboratory of Molecular and Cellular Biochemistry, Faculty of Dental Science, Kyushu University, Fukuoka, Japan (M.H.); Fukuoka Dental College, Fukuoka, Japan (M.H.)
| | - Tomonori Furukawa
- Graduate School of Medicine (Y.N.), Department of Neurophysiology (Y.N., T.F., K.K., S.U.) and Department of Anesthesiology, Graduate School of Medicine (Y.N., T.Ku., K.H.), Research Center for Child Mental Development, Graduate School of Medicine (S.S., S.U.), and Department of Biomedical Sciences, Division of Medical Life Sciences, Graduate School of Health Sciences (J.Y.), Hirosaki University, Hirosaki, Japan; Department of Drug Informatics, Faculty of Pharmaceutical Sciences, Fukuoka University, Fukuoka, Japan (K.M.); Department of Cellular and Molecular Pharmacology, Division of Basic Life Sciences, Institute of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan (T.Ka.); Laboratory of Molecular and Cellular Biochemistry, Faculty of Dental Science, Kyushu University, Fukuoka, Japan (M.H.); Fukuoka Dental College, Fukuoka, Japan (M.H.)
| | - Shuji Shimoyama
- Graduate School of Medicine (Y.N.), Department of Neurophysiology (Y.N., T.F., K.K., S.U.) and Department of Anesthesiology, Graduate School of Medicine (Y.N., T.Ku., K.H.), Research Center for Child Mental Development, Graduate School of Medicine (S.S., S.U.), and Department of Biomedical Sciences, Division of Medical Life Sciences, Graduate School of Health Sciences (J.Y.), Hirosaki University, Hirosaki, Japan; Department of Drug Informatics, Faculty of Pharmaceutical Sciences, Fukuoka University, Fukuoka, Japan (K.M.); Department of Cellular and Molecular Pharmacology, Division of Basic Life Sciences, Institute of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan (T.Ka.); Laboratory of Molecular and Cellular Biochemistry, Faculty of Dental Science, Kyushu University, Fukuoka, Japan (M.H.); Fukuoka Dental College, Fukuoka, Japan (M.H.)
| | - Junko Yamada
- Graduate School of Medicine (Y.N.), Department of Neurophysiology (Y.N., T.F., K.K., S.U.) and Department of Anesthesiology, Graduate School of Medicine (Y.N., T.Ku., K.H.), Research Center for Child Mental Development, Graduate School of Medicine (S.S., S.U.), and Department of Biomedical Sciences, Division of Medical Life Sciences, Graduate School of Health Sciences (J.Y.), Hirosaki University, Hirosaki, Japan; Department of Drug Informatics, Faculty of Pharmaceutical Sciences, Fukuoka University, Fukuoka, Japan (K.M.); Department of Cellular and Molecular Pharmacology, Division of Basic Life Sciences, Institute of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan (T.Ka.); Laboratory of Molecular and Cellular Biochemistry, Faculty of Dental Science, Kyushu University, Fukuoka, Japan (M.H.); Fukuoka Dental College, Fukuoka, Japan (M.H.)
| | - Keisuke Migita
- Graduate School of Medicine (Y.N.), Department of Neurophysiology (Y.N., T.F., K.K., S.U.) and Department of Anesthesiology, Graduate School of Medicine (Y.N., T.Ku., K.H.), Research Center for Child Mental Development, Graduate School of Medicine (S.S., S.U.), and Department of Biomedical Sciences, Division of Medical Life Sciences, Graduate School of Health Sciences (J.Y.), Hirosaki University, Hirosaki, Japan; Department of Drug Informatics, Faculty of Pharmaceutical Sciences, Fukuoka University, Fukuoka, Japan (K.M.); Department of Cellular and Molecular Pharmacology, Division of Basic Life Sciences, Institute of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan (T.Ka.); Laboratory of Molecular and Cellular Biochemistry, Faculty of Dental Science, Kyushu University, Fukuoka, Japan (M.H.); Fukuoka Dental College, Fukuoka, Japan (M.H.)
| | - Kohei Koga
- Graduate School of Medicine (Y.N.), Department of Neurophysiology (Y.N., T.F., K.K., S.U.) and Department of Anesthesiology, Graduate School of Medicine (Y.N., T.Ku., K.H.), Research Center for Child Mental Development, Graduate School of Medicine (S.S., S.U.), and Department of Biomedical Sciences, Division of Medical Life Sciences, Graduate School of Health Sciences (J.Y.), Hirosaki University, Hirosaki, Japan; Department of Drug Informatics, Faculty of Pharmaceutical Sciences, Fukuoka University, Fukuoka, Japan (K.M.); Department of Cellular and Molecular Pharmacology, Division of Basic Life Sciences, Institute of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan (T.Ka.); Laboratory of Molecular and Cellular Biochemistry, Faculty of Dental Science, Kyushu University, Fukuoka, Japan (M.H.); Fukuoka Dental College, Fukuoka, Japan (M.H.)
| | - Tetsuya Kushikata
- Graduate School of Medicine (Y.N.), Department of Neurophysiology (Y.N., T.F., K.K., S.U.) and Department of Anesthesiology, Graduate School of Medicine (Y.N., T.Ku., K.H.), Research Center for Child Mental Development, Graduate School of Medicine (S.S., S.U.), and Department of Biomedical Sciences, Division of Medical Life Sciences, Graduate School of Health Sciences (J.Y.), Hirosaki University, Hirosaki, Japan; Department of Drug Informatics, Faculty of Pharmaceutical Sciences, Fukuoka University, Fukuoka, Japan (K.M.); Department of Cellular and Molecular Pharmacology, Division of Basic Life Sciences, Institute of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan (T.Ka.); Laboratory of Molecular and Cellular Biochemistry, Faculty of Dental Science, Kyushu University, Fukuoka, Japan (M.H.); Fukuoka Dental College, Fukuoka, Japan (M.H.)
| | - Kazuyoshi Hirota
- Graduate School of Medicine (Y.N.), Department of Neurophysiology (Y.N., T.F., K.K., S.U.) and Department of Anesthesiology, Graduate School of Medicine (Y.N., T.Ku., K.H.), Research Center for Child Mental Development, Graduate School of Medicine (S.S., S.U.), and Department of Biomedical Sciences, Division of Medical Life Sciences, Graduate School of Health Sciences (J.Y.), Hirosaki University, Hirosaki, Japan; Department of Drug Informatics, Faculty of Pharmaceutical Sciences, Fukuoka University, Fukuoka, Japan (K.M.); Department of Cellular and Molecular Pharmacology, Division of Basic Life Sciences, Institute of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan (T.Ka.); Laboratory of Molecular and Cellular Biochemistry, Faculty of Dental Science, Kyushu University, Fukuoka, Japan (M.H.); Fukuoka Dental College, Fukuoka, Japan (M.H.)
| | - Takashi Kanematsu
- Graduate School of Medicine (Y.N.), Department of Neurophysiology (Y.N., T.F., K.K., S.U.) and Department of Anesthesiology, Graduate School of Medicine (Y.N., T.Ku., K.H.), Research Center for Child Mental Development, Graduate School of Medicine (S.S., S.U.), and Department of Biomedical Sciences, Division of Medical Life Sciences, Graduate School of Health Sciences (J.Y.), Hirosaki University, Hirosaki, Japan; Department of Drug Informatics, Faculty of Pharmaceutical Sciences, Fukuoka University, Fukuoka, Japan (K.M.); Department of Cellular and Molecular Pharmacology, Division of Basic Life Sciences, Institute of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan (T.Ka.); Laboratory of Molecular and Cellular Biochemistry, Faculty of Dental Science, Kyushu University, Fukuoka, Japan (M.H.); Fukuoka Dental College, Fukuoka, Japan (M.H.)
| | - Masato Hirata
- Graduate School of Medicine (Y.N.), Department of Neurophysiology (Y.N., T.F., K.K., S.U.) and Department of Anesthesiology, Graduate School of Medicine (Y.N., T.Ku., K.H.), Research Center for Child Mental Development, Graduate School of Medicine (S.S., S.U.), and Department of Biomedical Sciences, Division of Medical Life Sciences, Graduate School of Health Sciences (J.Y.), Hirosaki University, Hirosaki, Japan; Department of Drug Informatics, Faculty of Pharmaceutical Sciences, Fukuoka University, Fukuoka, Japan (K.M.); Department of Cellular and Molecular Pharmacology, Division of Basic Life Sciences, Institute of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan (T.Ka.); Laboratory of Molecular and Cellular Biochemistry, Faculty of Dental Science, Kyushu University, Fukuoka, Japan (M.H.); Fukuoka Dental College, Fukuoka, Japan (M.H.)
| | - Shinya Ueno
- Graduate School of Medicine (Y.N.), Department of Neurophysiology (Y.N., T.F., K.K., S.U.) and Department of Anesthesiology, Graduate School of Medicine (Y.N., T.Ku., K.H.), Research Center for Child Mental Development, Graduate School of Medicine (S.S., S.U.), and Department of Biomedical Sciences, Division of Medical Life Sciences, Graduate School of Health Sciences (J.Y.), Hirosaki University, Hirosaki, Japan; Department of Drug Informatics, Faculty of Pharmaceutical Sciences, Fukuoka University, Fukuoka, Japan (K.M.); Department of Cellular and Molecular Pharmacology, Division of Basic Life Sciences, Institute of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan (T.Ka.); Laboratory of Molecular and Cellular Biochemistry, Faculty of Dental Science, Kyushu University, Fukuoka, Japan (M.H.); Fukuoka Dental College, Fukuoka, Japan (M.H.)
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General anesthetic actions on GABA A receptors in vivo are reduced in phospholipase C-related catalytically inactive protein knockout mice. J Anesth 2017; 31:531-538. [PMID: 28389811 DOI: 10.1007/s00540-017-2350-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2016] [Accepted: 03/26/2017] [Indexed: 10/19/2022]
Abstract
PURPOSE The aim of this study was to investigate the action of general anesthetics in phospholipase C-related catalytically inactive protein (PRIP)-knockout (KO) mice that alter GABAA receptor signaling. METHODS PRIP regulates the intracellular trafficking of β subunit-containing GABAA receptors in vitro. In this study, we examined the effects of intravenous anesthetics, propofol and etomidate that act via β subunit-containing GABAA receptors, in wild-type and Prip-KO mice. Mice were intraperitoneally injected with a drug, and a loss of righting reflex (LORR) assay and an electroencephalogram analysis were performed. RESULTS The cell surface expression of GABAA receptor β3 subunit detected by immunoblotting was decreased in Prip-knockout brain compared with that in wild-type brain without changing the expression of other GABAA receptor subunits. Propofol-treated Prip-KO mice exhibited significantly shorter duration of LORR and had lower total anesthetic score than wild-type mice in the LORR assay. The average duration of sleep time in an electroencephalogram analysis was shorter in propofol-treated Prip-KO mice than in wild-type mice. The hypnotic action of etomidate was also reduced in Prip-KO mice. However, ketamine, an NMDA receptor antagonist, had similar effects in the two genotypes. CONCLUSION PRIP regulates the cell surface expression of the GABAA receptor β3 subunit and modulates general anesthetic action in vivo. Elucidation of the involved regulatory mechanisms of GABAA receptor-dependent signaling would inform the development of safer anesthetic therapies for clinical applications.
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Chiara DC, Jounaidi Y, Zhou X, Savechenkov PY, Bruzik KS, Miller KW, Cohen JB. General Anesthetic Binding Sites in Human α4β3δ γ-Aminobutyric Acid Type A Receptors (GABAARs). J Biol Chem 2016; 291:26529-26539. [PMID: 27821594 PMCID: PMC5159512 DOI: 10.1074/jbc.m116.753335] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2016] [Revised: 10/14/2016] [Indexed: 01/08/2023] Open
Abstract
Extrasynaptic γ-aminobutyric acid type A receptors (GABAARs),which contribute generalized inhibitory tone to the mammalian brain, are major targets for general anesthetics. To identify anesthetic binding sites in an extrasynaptic GABAAR, we photolabeled human α4β3δ GABAARs purified in detergent with [3H]azietomidate and a barbiturate, [3H]R-mTFD-MPAB, photoreactive anesthetics that bind with high selectivity to distinct but homologous intersubunit binding sites in the transmembrane domain of synaptic α1β3γ2 GABAARs. Based upon 3H incorporation into receptor subunits resolved by SDS-PAGE, there was etomidate-inhibitable labeling by [3H]azietomidate in the α4 and β3 subunits and barbiturate-inhibitable labeling by [3H]R-mTFD-MPAB in the β3 subunit. These sites did not bind the anesthetic steroid alphaxalone, which enhanced photolabeling, or DS-2, a δ subunit-selective positive allosteric modulator, which neither enhanced nor inhibited photolabeling. The amino acids labeled by [3H]azietomidate or [3H]R-mTFD-MPAB were identified by N-terminal sequencing of fragments isolated by HPLC fractionation of enzymatically digested subunits. No evidence was found for a δ subunit contribution to an anesthetic binding site. [3H]azietomidate photolabeling of β3Met-286 in βM3 and α4Met-269 in αM1 that was inhibited by etomidate but not by R-mTFD-MPAB established that etomidate binds to a site at the β3+-α4- interface equivalent to its site in α1β3γ2 GABAARs. [3H]Azietomidate and [3H]R-mTFD-MPAB photolabeling of β3Met-227 in βM1 established that these anesthetics also bind to a homologous site, most likely at the β3+-β3- interface, which suggests a subunit arrangement of β3α4β3δβ3.
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Affiliation(s)
| | - Youssef Jounaidi
- the Department of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital, Boston, Massachusetts 02114, and
| | - Xiaojuan Zhou
- the Department of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital, Boston, Massachusetts 02114, and
| | - Pavel Y Savechenkov
- the Department of Medicinal Chemistry and Pharmacognosy, University of Illinois, Chicago, Illinois 60612
| | - Karol S Bruzik
- the Department of Medicinal Chemistry and Pharmacognosy, University of Illinois, Chicago, Illinois 60612
| | - Keith W Miller
- the Department of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital, Boston, Massachusetts 02114, and
- Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts 02115
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Park H, Ryu K, Kim YH, Choi WJ, Ko D. The effects of etomidate and midazolam on adipose tissue-derived mesenchymal stem cell proliferation. Korean J Anesthesiol 2016; 69:614-618. [PMID: 27924203 PMCID: PMC5133234 DOI: 10.4097/kjae.2016.69.6.614] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2015] [Revised: 05/25/2016] [Accepted: 07/07/2016] [Indexed: 11/10/2022] Open
Abstract
Background Stem cell therapy using adipose tissue-derived mesenchymal stem cells (ADSCs), which are capable of multipotent differentiation, is currently being investigated in the field of tissue regeneration and the treatment of patients in intensive care units. It is known that type-A γ-aminobutyric acid (GABAA) receptor activity has an influence on stem cell proliferation. Thus, we investigated the effects of the clinically available GABAA receptor agonists, etomidate and midazolam, on ADSC proliferation measured by the cell counting kit-8 assay. Methods ADSCs cultured in control medium or adipogenic differentiation medium for 15 days were divided into 5 treatment groups: non-medicated (Control) and 4 groups including treatment with etomidate or midazolam at 1 and 50 µM (n = 3 per group). The cell counting kit-8 assay was performed for determining the cell proliferation in both medium groups at day 0, 3, 6, 9, 12, and 15 in culture. The absorbance values at 450 nm were then measured by enzyme-linked immunosorbent assay reader and statistically compared among groups. Results There was no significant difference in cell proliferation profiles among the 5 groups at any time point in both control and adipogenic differentiation media. Conclusions Etomidate and midazolam did not influence ADSC proliferation under both media when compared to the non-medicated group and there was no dose-dependent effect of etomidate and midazolam on ADSC viability.
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Affiliation(s)
- Ho Park
- Department of Clinical Laboratory Science, Wonkwang Health Science University, Iksan, Korea
| | - Kyoungho Ryu
- Department of Anesthesiology and Pain Medicine, Kangbuk Samsung Hospital, Sungkyunkwan University School of Medicine, Seoul, Korea
| | - Yun-Hong Kim
- Department of Anesthesiology and Pain Medicine, Kangbuk Samsung Hospital, Sungkyunkwan University School of Medicine, Seoul, Korea
| | - Won-Jun Choi
- Department of Anesthesiology and Pain Medicine, Kangbuk Samsung Hospital, Sungkyunkwan University School of Medicine, Seoul, Korea
| | - Dongchan Ko
- Department of Anesthesiology and Pain Medicine, Kangbuk Samsung Hospital, Sungkyunkwan University School of Medicine, Seoul, Korea
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Amlong CA, Perkins MG, Houle TT, Miller KW, Pearce RA. Contrasting Effects of the γ-Aminobutyric Acid Type A Receptor β3 Subunit N265M Mutation on Loss of Righting Reflexes Induced by Etomidate and the Novel Anesthetic Barbiturate R-mTFD-MPAB. Anesth Analg 2016; 123:1241-1246. [PMID: 27331778 PMCID: PMC5072997 DOI: 10.1213/ane.0000000000001358] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
BACKGROUND Previous studies have shown that etomidate modulates γ-aminobutyric acid type A receptors by binding at the β-α subunit interface within the transmembrane domain of receptors that incorporate β2 or β3 subunits. Introducing an asparagine-to-methionine (N265M) mutation at position 265 of the β3 subunit, which sits within the etomidate-binding site, attenuates the hypnotic effect of etomidate in vivo. It was reported recently that the photoactivatable barbiturate R-mTFD-MPAB also acts on γ-aminobutyric acid type A receptors primarily by binding to a homologous site at the γ-β interface. Given this difference in drug-binding sites established by the in vitro experiments, we hypothesized that the β3-N265M-mutant mice would not be resistant to the anesthetic effects of R-mTFD-MPAB in vivo, whereas the same mutant mice would be resistant to the anesthetic effects of R-etomidate. METHODS We measured the effects of IV injection of etomidate and R-mTFD-MPAB on loss and recovery of righting reflex in wild-type mice and in mice carrying the β3-N265M mutation. RESULTS Etomidate-induced hypnosis, as measured by the duration of loss of righting reflex, was attenuated in the N265M knock-in mice, confirming prior results. By contrast, recovery of balance and coordinated movement, as measured by the ability to maintain all 4 paws on the ground, was unaffected by the mutation. Neither hypnosis nor impairment of coordinated movement produced by the barbiturate R-mTFD-MPAB was affected by the mutation. CONCLUSIONS The findings confirmed our hypothesis that mutating the etomidate-binding site would not alter the response to the barbiturate R-mTFD-MPAB. Furthermore, we confirmed previous studies indicating that etomidate-induced hypnosis is mediated in part by β3-containing receptors. We also extended previous findings by showing that etomidate-impaired balance and coordinated movement are not mediated by β3-containing receptors, thus implicating β2-containing receptors in this end point.
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Affiliation(s)
- Corey A Amlong
- From the *Department of Anesthesiology, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin; and †Department of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital, Boston, Massachusetts
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Stephens DN, King SL, Lambert JJ, Belelli D, Duka T. GABAAreceptor subtype involvement in addictive behaviour. GENES BRAIN AND BEHAVIOR 2016; 16:149-184. [DOI: 10.1111/gbb.12321] [Citation(s) in RCA: 62] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/31/2016] [Revised: 07/19/2016] [Accepted: 08/15/2016] [Indexed: 12/17/2022]
Affiliation(s)
| | - S. L. King
- School of Psychology; University of Sussex; Brighton UK
| | - J. J. Lambert
- Division of Neuroscience; University of Dundee; Dundee UK
| | - D. Belelli
- Division of Neuroscience; University of Dundee; Dundee UK
| | - T. Duka
- School of Psychology; University of Sussex; Brighton UK
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Germann AL, Shin DJ, Manion BD, Edge CJ, Smith EH, Franks NP, Evers AS, Akk G. Activation and modulation of recombinant glycine and GABA A receptors by 4-halogenated analogues of propofol. Br J Pharmacol 2016; 173:3110-3120. [PMID: 27459129 DOI: 10.1111/bph.13566] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2016] [Revised: 07/11/2016] [Accepted: 07/20/2016] [Indexed: 01/26/2023] Open
Abstract
BACKGROUND AND PURPOSE Glycine receptors are important players in pain perception and movement disorders and therefore important therapeutic targets. Glycine receptors can be modulated by the intravenous anaesthetic propofol (2,6-diisopropylphenol). However, the drug is more potent, by at least one order of magnitude, on GABAA receptors. It has been proposed that halogenation of the propofol molecule generates compounds with selective enhancement of glycinergic modulatory properties. EXPERIMENTAL APPROACH We synthesized 4-bromopropofol, 4-chloropropofol and 4-fluoropropofol. The direct activating and modulatory effects of these drugs and propofol were compared on recombinant rat glycine and human GABAA receptors expressed in oocytes. Behavioural effects of the compounds were compared in the tadpole loss-of-righting assay. KEY RESULTS Concentration-response curves for potentiation of homomeric α1, α2 and α3 glycine receptors were shifted to lower drug concentrations, by 2-10-fold, for the halogenated compounds. Direct activation by all compounds was minimal with all subtypes of the glycine receptor. The four compounds were essentially equally potent modulators of the α1β3γ2L GABAA receptor with EC50 between 4 and 7 μM. The EC50 for loss-of-righting in Xenopus tadpoles, a proxy for loss of consciousness and considered to be mediated by actions on GABAA receptors, ranged from 0.35 to 0.87 μM. CONCLUSIONS AND IMPLICATIONS We confirm that halogenation of propofol more strongly affects modulation of homomeric glycine receptors than α1β3γ2L GABAA receptors. However, the effective concentrations of all tested halogenated compounds remained lower for GABAA receptors. We infer that 4-bromopropofol, 4-chloropropofol and 4-fluoropropofol are not selective homomeric glycine receptor modulators.
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Affiliation(s)
- Allison L Germann
- Department of Anesthesiology, Washington University School of Medicine, St. Louis, MO, USA
| | - Daniel J Shin
- Department of Anesthesiology, Washington University School of Medicine, St. Louis, MO, USA
| | - Brad D Manion
- Department of Anesthesiology, Washington University School of Medicine, St. Louis, MO, USA
| | - Christopher J Edge
- Department of Life Sciences, Imperial College London, South Kensington, UK.,Department of Anaesthetics, Royal Berkshire NHS Foundation Trust, Reading, UK
| | - Edward H Smith
- Department of Life Sciences, Imperial College London, South Kensington, UK
| | - Nicholas P Franks
- Department of Life Sciences, Imperial College London, South Kensington, UK
| | - Alex S Evers
- Department of Anesthesiology, Washington University School of Medicine, St. Louis, MO, USA.,Taylor Family Institute for Innovative Psychiatric Research, Washington University School of Medicine, St. Louis, MO, USA
| | - Gustav Akk
- Department of Anesthesiology, Washington University School of Medicine, St. Louis, MO, USA. .,Taylor Family Institute for Innovative Psychiatric Research, Washington University School of Medicine, St. Louis, MO, USA.
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Tuk B. Overstimulation of the inhibitory nervous system plays a role in the pathogenesis of neuromuscular and neurological diseases: a novel hypothesis. F1000Res 2016; 5:1435. [PMID: 27547379 PMCID: PMC4984481 DOI: 10.12688/f1000research.8774.2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 08/12/2016] [Indexed: 11/20/2022] Open
Abstract
Based upon a thorough review of published clinical observations regarding the inhibitory system, I hypothesize that this system may play a key role in the pathogenesis of a variety of neuromuscular and neurological diseases. Specifically, excitatory overstimulation, which is commonly reported in neuromuscular and neurological diseases, may be a homeostatic response to inhibitory overstimulation. Involvement of the inhibitory system in disease pathogenesis is highly relevant, given that most approaches currently being developed for treating neuromuscular and neurological diseases focus on reducing excitatory activity rather than reducing inhibitory activity.
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Affiliation(s)
- Bert Tuk
- Leiden Academic Center for Drug Research (LACDR), Leiden University, Leiden, 2333 CC, Netherlands; Ry Pharma, Hofstraat 1, Willemstad, 4797 AC, Netherlands
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