Many clinically-used sedative and anesthetic agents act by modulating the function of the ?-aminobutyric acid type A (GABAA) receptor. The GABAA receptor is the major inhibitory transmittergated ion channel in the brain. Inhibition mediated by GABAA receptors sets the overall activity of the brain, while in individual cells it determines the propensity of a cell to fire an action potential in response to a given excitatory input. The GABAA receptor is also a target for numerous endogenous compounds including neuroactive steroids, that can reduce the dosage requirement for intravenous anesthetics. The overall goal of this project is to investigate how various endogenous compounds and clinically used drugs modify the functioning of the GABAA receptor and initiate the onset and offset of anesthesia. Specifically, we will: i) examine the interactions between binding sites for various classes of GABAergic anesthetics; ii) test the hypothesis that modulation of tonic activity from synaptic-type GABAA receptors contributes to the actions of anesthetics; iii) determine the effects of anesthetic drug combinations on the function of native GABAA receptors; iv) test the hypothesis that endogenous steroids act as co-agonists enhancing the behavioral effects of clinically used GABAergic anesthetic drugs; and v) test the usefulness of competitive steroid-antagonists in promoting emergence from anesthesia.

Public Health Relevance

The GABAA receptor is a major target for intravenous anesthetics. The project will investigate how various endogenous and clinically-used sedative compounds affect the functioning of the GABAA receptor and control the onset and offset of anesthesia.

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Research Project (R01)
Project #
3R01GM108580-06S1
Application #
10145994
Study Section
Program Officer
Justinova, Zuzana
Project Start
2014-08-01
Project End
2022-11-30
Budget Start
2019-12-01
Budget End
2020-11-30
Support Year
6
Fiscal Year
2020
Total Cost
Indirect Cost
Name
Washington University
Department
Anesthesiology
Type
Schools of Medicine
DUNS #
068552207
City
Saint Louis
State
MO
Country
United States
Zip Code
63130
Cheng, Wayland W L; Chen, Zi-Wei; Bracamontes, John R et al. (2018) Mapping two neurosteroid-modulatory sites in the prototypic pentameric ligand-gated ion channel GLIC. J Biol Chem 293:3013-3027
Cao, Lily Q; Montana, Michael C; Germann, Allison L et al. (2018) Enhanced GABAergic actions resulting from the coapplication of the steroid 3?-hydroxy-5?-pregnane-11,20-dione (alfaxalone) with propofol or diazepam. Sci Rep 8:10341
Germann, Allison L; Shin, Daniel J; Kuhrau, Christina R et al. (2018) High Constitutive Activity Accounts for the Combination of Enhanced Direct Activation and Reduced Potentiation in Mutated GABAA Receptors. Mol Pharmacol 93:468-476
Shin, Daniel J; Germann, Allison L; Johnson, Alexander D et al. (2018) Propofol Is an Allosteric Agonist with Multiple Binding Sites on Concatemeric Ternary GABAA Receptors. Mol Pharmacol 93:178-189
Sun, Min-Yu; Shu, Hong-Jin; Benz, Ann et al. (2018) Chemogenetic Isolation Reveals Synaptic Contribution of ? GABAA Receptors in Mouse Dentate Granule Neurons. J Neurosci 38:8128-8145
Akk, Gustav; Shin, Daniel J; Germann, Allison L et al. (2018) GABA Type A Receptor Activation in the Allosteric Coagonist Model Framework: Relationship between EC50 and Basal Activity. Mol Pharmacol 93:90-100
Shin, Daniel J; Germann, Allison L; Steinbach, Joe Henry et al. (2017) The Actions of Drug Combinations on the GABAA Receptor Manifest as Curvilinear Isoboles of Additivity. Mol Pharmacol 92:556-563
Bracamontes, John R; Akk, Gustav; Steinbach, Joe Henry (2016) Introduced Amino Terminal Epitopes Can Reduce Surface Expression of Neuronal Nicotinic Receptors. PLoS One 11:e0151071
Eaton, Megan M; Germann, Allison L; Arora, Ruby et al. (2016) Multiple Non-Equivalent Interfaces Mediate Direct Activation of GABAA Receptors by Propofol. Curr Neuropharmacol 14:772-80
Germann, Allison L; Shin, Daniel J; Manion, Brad D et al. (2016) Activation and modulation of recombinant glycine and GABAA receptors by 4-halogenated analogues of propofol. Br J Pharmacol 173:3110-3120

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