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Song XJ, Hu JJ. Neurobiological basis of emergence from anesthesia. Trends Neurosci 2024:S0166-2236(24)00022-5. [PMID: 38490858 DOI: 10.1016/j.tins.2024.02.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [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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2
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Zhang Q, Forster-Gibson C, Bercovici E, Bernardo A, Ding F, Shen W, Langer K, Rex T, Kang JQ. Epilepsy plus blindness in microdeletion of GABRA1 and GABRG2 in mouse and human. Exp Neurol 2023; 369:114537. [PMID: 37703949 PMCID: PMC10591898 DOI: 10.1016/j.expneurol.2023.114537] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2023] [Revised: 08/24/2023] [Accepted: 09/07/2023] [Indexed: 09/15/2023]
Abstract
OBJECTIVE GABAA receptor subunit gene (GABR) mutations are significant causes of epilepsy, including syndromic epilepsy. This report for the first time, describes intractable epilepsy and blindness due to optic atrophy in our patient, who has a microdeletion of the GABRA1 and GABRG2 genes. We then characterized the molecular phenotypes and determined patho-mechanisms underlying the genotype-phenotype correlations in a mouse model who is haploinsufficient for both genes (Gabra1+/-/Gabrg2+/- mouse). METHODS Electroencephalography was conducted in both human and mice with the same gene loss. GABAA receptor expression was evaluated by biochemical and imaging approaches. Optic nerve atrophy was evaluated with fundus photography in human while electronic microscopy, visual evoked potential and electroretinography recordings were conducted in mice. RESULTS The patient has bilateral optical nerve atrophy. Mice displayed spontaneous seizures, reduced electroretinography oscillatory potential and reduced GABAA receptor α1, β2 and γ2 subunit expression in various brain regions. Electronic microscopy showed that mice also had optic nerve degeneration, as indicated by increased G-ratio, the ratio of the inner axonal diameter to the total outer diameter, suggesting impaired myelination of axons. More importantly, we identified that phenobarbital was the most effective anticonvulsant in mice and the patient's seizures were also controlled with phenobarbital after failing multiple anti-seizure drugs. CONCLUSIONS This study is the first report of haploinsufficiency of two GABR epilepsy genes and visual impairment due to altered axonal myelination and resultant optic nerve atrophy. The study suggests the far-reaching impact of GABR mutations and the translational significance of animal models with the same etiology.
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Affiliation(s)
- Qi Zhang
- Department of Neurology, Vanderbilt University Medical Center, Nashville, TN 37212, United States of America; Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, Co-innovation Center of Neuroregeneration, Department of Neurology, Nantong University, 19 Qixiu Road, Nantong, JS 226001, PR China
| | - Cynthia Forster-Gibson
- Laboratory Medicine and Genetics, Trillium Health Partners, Mississauga and Laboratory Medicine and Pathobiology, Faculty of Medicine, University of Toronto, Canada
| | - Eduard Bercovici
- Division of Neurology, Faculty of Medicine, University of Toronto, Canada
| | - Alexandra Bernardo
- Department of Ophthalmology & Visual Sciences Vanderbilt Eye Institute, Vanderbilt University Medical Center, Nashville, TN 37212, United States of America
| | - Fei Ding
- Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, Co-innovation Center of Neuroregeneration, Department of Neurology, Nantong University, 19 Qixiu Road, Nantong, JS 226001, PR China
| | - Wangzhen Shen
- Department of Neurology, Vanderbilt University Medical Center, Nashville, TN 37212, United States of America
| | - Katherine Langer
- Department of Neurology, Vanderbilt University Medical Center, Nashville, TN 37212, United States of America
| | - Tonia Rex
- Department of Ophthalmology & Visual Sciences Vanderbilt Eye Institute, Vanderbilt University Medical Center, Nashville, TN 37212, United States of America
| | - Jing-Qiong Kang
- Department of Neurology, Vanderbilt University Medical Center, Nashville, TN 37212, United States of America; Department of Pharmacology, Vanderbilt University, United States of America; Vanderbilt Brain Institute and Vanderbilt Kennedy Center of Human Development, Vanderbilt University, Nashville, TN 37212, United States of America.
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3
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Cowgill J, Fan C, Haloi N, Tobiasson V, Zhuang Y, Howard RJ, Lindahl E. Structure and dynamics of differential ligand binding in the human ρ-type GABA A receptor. Neuron 2023; 111:3450-3464.e5. [PMID: 37659407 DOI: 10.1016/j.neuron.2023.08.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2023] [Revised: 08/01/2023] [Accepted: 08/07/2023] [Indexed: 09/04/2023]
Abstract
The neurotransmitter γ-aminobutyric acid (GABA) drives critical inhibitory processes in and beyond the nervous system, partly via ionotropic type-A receptors (GABAARs). Pharmacological properties of ρ-type GABAARs are particularly distinctive, yet the structural basis for their specialization remains unclear. Here, we present cryo-EM structures of a lipid-embedded human ρ1 GABAAR, including a partial intracellular domain, under apo, inhibited, and desensitized conditions. An apparent resting state, determined first in the absence of modulators, was recapitulated with the specific inhibitor (1,2,5,6-tetrahydropyridin-4-yl)methylphosphinic acid and blocker picrotoxin and provided a rationale for bicuculline insensitivity. Comparative structures, mutant recordings, and molecular simulations with and without GABA further explained the sensitized but slower activation of ρ1 relative to canonical subtypes. Combining GABA with picrotoxin also captured an apparent uncoupled intermediate state. This work reveals structural mechanisms of gating and modulation with applications to ρ-specific pharmaceutical design and to our biophysical understanding of ligand-gated ion channels.
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Affiliation(s)
- John Cowgill
- Department of Biochemistry and Biophysics, SciLifeLab, Stockholm University, 17121 Solna, Sweden
| | - Chen Fan
- Department of Biochemistry and Biophysics, SciLifeLab, Stockholm University, 17121 Solna, Sweden
| | - Nandan Haloi
- Department of Applied Physics, SciLifeLab, KTH Royal Institute of Technology, 17121 Solna, Sweden
| | - Victor Tobiasson
- Department of Biochemistry and Biophysics, SciLifeLab, Stockholm University, 17121 Solna, Sweden
| | - Yuxuan Zhuang
- Department of Biochemistry and Biophysics, SciLifeLab, Stockholm University, 17121 Solna, Sweden
| | - Rebecca J Howard
- Department of Biochemistry and Biophysics, SciLifeLab, Stockholm University, 17121 Solna, Sweden.
| | - Erik Lindahl
- Department of Biochemistry and Biophysics, SciLifeLab, Stockholm University, 17121 Solna, Sweden; Department of Applied Physics, SciLifeLab, KTH Royal Institute of Technology, 17121 Solna, Sweden.
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4
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Hannan SB, Penzinger R, Mickute G, Smart TG. CGP7930 - An allosteric modulator of GABA BRs, GABA ARs and inwardly-rectifying potassium channels. Neuropharmacology 2023; 238:109644. [PMID: 37422181 PMCID: PMC10951960 DOI: 10.1016/j.neuropharm.2023.109644] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2022] [Revised: 06/01/2023] [Accepted: 06/22/2023] [Indexed: 07/10/2023]
Abstract
Type-A and -B GABA receptors (GABAARs/GABABRs) control brain function and behaviour by fine tuning neurotransmission. Over-time these receptors have become important therapeutic targets for treating neurodevelopmental and neuropsychiatric disorders. Several positive allosteric modulators (PAMs) of GABARs have reached the clinic and selective targeting of receptor subtypes is crucial. For GABABRs, CGP7930 is a widely used PAM for in vivo studies, but its full pharmacological profile has not yet been established. Here, we reveal that CGP7930 has multiple effects not only on GABABRs but also GABAARs, which for the latter involves potentiation of GABA currents, direct receptor activation, and also inhibition. Furthermore, at higher concentrations, CGP7930 also blocks G protein-coupled inwardly-rectifying K+ (GIRK) channels diminishing GABABR signalling in HEK 293 cells. In male and female rat hippocampal neuron cultures, CGP7930 allosteric effects on GABAARs caused prolonged rise and decay times and reduced the frequency of inhibitory postsynaptic currents and potentiated GABAAR-mediated tonic inhibition. Additional comparison between predominant synaptic- and extrasynaptic-isoforms of GABAAR indicated no evident subtype selectivity for CGP7930. In conclusion, our study of CGP7930 modulation of GABAARs, GABABRs and GIRK channels, indicates this compound is unsuitable for use as a specific GABABR PAM.
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Affiliation(s)
- Saad B Hannan
- Department of Neuroscience, Physiology and Pharmacology, University College London, Gower Street, London, WC1E 6BT, UK.
| | - Reka Penzinger
- Department of Neuroscience, Physiology and Pharmacology, University College London, Gower Street, London, WC1E 6BT, UK
| | - Ginte Mickute
- Department of Neuroscience, Physiology and Pharmacology, University College London, Gower Street, London, WC1E 6BT, UK
| | - Trevor G Smart
- Department of Neuroscience, Physiology and Pharmacology, University College London, Gower Street, London, WC1E 6BT, UK.
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Le HTN, Rijal S, Jang SH, Park SA, Park SJ, Jung W, Han SK. Inhibitory Effects of Honokiol on Substantia Gelatinosa Neurons of the Trigeminal Subnucleus Caudalis in Juvenile Mice. Neuroscience 2023; 521:89-101. [PMID: 37142181 DOI: 10.1016/j.neuroscience.2023.04.022] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2022] [Revised: 04/18/2023] [Accepted: 04/25/2023] [Indexed: 05/06/2023]
Abstract
Inhibitory neurotransmitters such as gamma-aminobutyric acid (GABA) and glycine are known to be abundant in the substantia gelatinosa (SG) of the trigeminal subnucleus caudalis (Vc). Thus, it has been recognized as an initial synaptic site for regulating orofacial nociceptive stimuli. Honokiol, a principal active ingredient derived from the bark of Magnolia officinalis, has been exploited in traditional remedies with multiple biological effects, including anti-nociception on humans. However, the anti-nociceptive mechanism of honokiol on SG neurons of the Vc remains fully elusive. In this study, effects of honokiol on SG neurons of the Vc in mice were investigated using the whole-cell patch-clamp method. In a concentration-dependent manner, honokiol significantly enhanced frequencies of spontaneous postsynaptic currents (sPSCs) that were independent of action potential generation. Notably, honokiol-induced increase in the frequency of sPSCs was attributed to the release of inhibitory neurotransmitters through both glycinergic and GABAergic pre-synaptic terminals. Furthermore, higher concentration of honokiol induced inward currents that were noticeably attenuated in the presence of picrotoxin (a GABAA receptor antagonist) or strychnine (a glycine receptor antagonist). Honokiol also exhibited potentiation effect on glycine- and GABAA receptor-mediated responses. In inflammatory pain model, the increase in frequency of spontaneous firing on SG neurons induced by formalin was significantly inhibited by the application of honokiol. Altogether, these findings indicate that honokiol might directly affect SG neurons of the Vc to facilitate glycinergic and GABAergic neurotransmissions and modulate nociceptive synaptic transmission against pain. Consequently, the inhibitory effect of honokiol in the central nociceptive system contributes to orofacial pain management.
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Affiliation(s)
- Ha Thuy Nhung Le
- Department of Oral Physiology, School of Dentistry & Institute of Oral Bioscience, Jeonbuk National University, Jeonju, Republic of Korea; Faculty of Odonto-Stomatology, Hue University of Medicine and Pharmacy, Hue University, Hue, Viet Nam
| | - Santosh Rijal
- Department of Oral Physiology, School of Dentistry & Institute of Oral Bioscience, Jeonbuk National University, Jeonju, Republic of Korea
| | - Seon Hui Jang
- Department of Oral Physiology, School of Dentistry & Institute of Oral Bioscience, Jeonbuk National University, Jeonju, Republic of Korea
| | - Seon Ah Park
- Department of Oral Physiology, School of Dentistry & Institute of Oral Bioscience, Jeonbuk National University, Jeonju, Republic of Korea
| | - Soo Joung Park
- Department of Oral Physiology, School of Dentistry & Institute of Oral Bioscience, Jeonbuk National University, Jeonju, Republic of Korea
| | - Won Jung
- Department of Oral Medicine, School of Dentistry & Institute of Oral Bioscience, Jeonbuk National University, Research Institute of Clinical Medicine of Jeonbuk National University - Biomedical Research Institute of Jeonbuk National University Hospital, Jeonju, Republic of Korea.
| | - Seong Kyu Han
- Department of Oral Physiology, School of Dentistry & Institute of Oral Bioscience, Jeonbuk National University, Jeonju, Republic of Korea.
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Covey DF, Evers AS, Izumi Y, Maguire JL, Mennerick SJ, Zorumski CF. Neurosteroid enantiomers as potentially novel neurotherapeutics. Neurosci Biobehav Rev 2023; 149:105191. [PMID: 37085023 PMCID: PMC10750765 DOI: 10.1016/j.neubiorev.2023.105191] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2022] [Revised: 04/17/2023] [Accepted: 04/18/2023] [Indexed: 04/23/2023]
Abstract
Endogenous neurosteroids and synthetic neuroactive steroids (NAS) are important targets for therapeutic development in neuropsychiatric disorders. These steroids modulate major signaling systems in the brain and intracellular processes including inflammation, cellular stress and autophagy. In this review, we describe studies performed using unnatural enantiomers of key neurosteroids, which are physiochemically identical to their natural counterparts except for rotation of polarized light. These studies led to insights in how NAS interact with receptors, ion channels and intracellular sites of action. Certain effects of NAS show high enantioselectivity, consistent with actions in chiral environments and likely direct interactions with signaling proteins. Other effects show no enantioselectivity and even reverse enantioselectivity. The spectrum of effects of NAS enantiomers raises the possibility that these agents, once considered only as tools for preclinical studies, have therapeutic potential that complements and in some cases may exceed their natural counterparts. Here we review studies of NAS enantiomers from the perspective of their potential development as novel neurotherapeutics.
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Affiliation(s)
- Douglas F Covey
- Departments of Psychiatry, Washington University School of Medicine, St. Louis, MO, USA; Developmental Biology, Washington University School of Medicine, St. Louis, MO, USA; 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
| | - Alex S Evers
- Developmental Biology, Washington University School of Medicine, St. Louis, MO, USA; 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
| | - Yukitoshi Izumi
- Departments of Psychiatry, 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
| | - Jamie L Maguire
- Department of Neuroscience, Tufts University School of Medicine, Boston, MA, USA
| | - Steven J Mennerick
- Departments of Psychiatry, 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
| | - Charles F Zorumski
- Departments of Psychiatry, 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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7
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Seljeset S, Liebowitz S, Bright DP, Smart TG. Pre- and postsynaptic modulation of hippocampal inhibitory synaptic transmission by pregnenolone sulphate. Neuropharmacology 2023; 233:109530. [PMID: 37037282 DOI: 10.1016/j.neuropharm.2023.109530] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2022] [Revised: 03/28/2023] [Accepted: 03/31/2023] [Indexed: 04/12/2023]
Abstract
Neurosteroids are important endogenous modulators of GABAA receptor-mediated neurotransmission within the CNS and play a vital role in maintaining normal healthy brain function. Research has mainly focussed on neurosteroids such as allopregnanolone and tetrahydro-deoxycorticosterone (THDOC) which are allosteric potentiators of GABAA receptors, whilst the sulphated steroids, including pregnenolone sulphate (PS), which inhibit GABAA receptor function, have been relatively neglected. Importantly, a full description of PS effects on inhibitory synaptic transmission, at concentrations that are expected to inhibit postsynaptic GABAA receptors, is lacking. Here, we address this deficit by recording inhibitory postsynaptic currents (IPSCs) from rat hippocampal neurons both in culture and in acute brain slices and explore the impact of PS at micromolar concentrations. We reveal that PS inhibits postsynaptic GABAA receptors, evident from reductions in IPSC amplitude and decay time. Concurrently, PS also causes an increase in synaptic GABA release which we discover is due to the activation of presynaptic TRPM3 receptors located close to presynaptic GABA release sites. Pharmacological blockade of TRPM3 receptors uncovers a PS-evoked reduction in IPSC frequency. This second presynaptic effect is caused by PS activation of inwardly-rectifying Kir2.3 channels on interneurons, which act to depress synaptic GABA release. Overall, we provide a comprehensive characterisation of pre- and postsynaptic modulation by PS of inhibitory synaptic transmission onto hippocampal neurons which elucidates the diverse mechanisms by which this understudied neurosteroid can modulate brain function.
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Affiliation(s)
- Sandra Seljeset
- Department of Neuroscience, Physiology & Pharmacology, UCL, Gower Street, London, WC1E 6BT, UK
| | - Seth Liebowitz
- Department of Neuroscience, Physiology & Pharmacology, UCL, Gower Street, London, WC1E 6BT, UK
| | - Damian P Bright
- Department of Neuroscience, Physiology & Pharmacology, UCL, Gower Street, London, WC1E 6BT, UK.
| | - Trevor G Smart
- Department of Neuroscience, Physiology & Pharmacology, UCL, Gower Street, London, WC1E 6BT, UK.
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8
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Kłopotowski K, Michałowski MA, Gos M, Mosiądz D, Czyżewska MM, Mozrzymas JW. Mutation of valine 53 at the interface between extracellular and transmembrane domains of the β 2 principal subunit affects the GABA A receptor gating. Eur J Pharmacol 2023; 947:175664. [PMID: 36934960 DOI: 10.1016/j.ejphar.2023.175664] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2022] [Revised: 02/09/2023] [Accepted: 03/16/2023] [Indexed: 03/21/2023]
Abstract
GABAA receptors (gamma-aminobutyric acid type A receptors) are pentameric ligand-gated ion channels mediating inhibition in adult mammalian brains. Their static structure has been intensely studied in the past years but the underlying molecular activatory mechanisms remain obscure. The interface between extracellular and transmembrane domains has been recognized as a key player in the receptor gating. However, the role of the valine 53 in the β1-β2 loop of the principal subunit (β2) remains controversial showing differences compared to homologous residues in some cys-loop counterparts such as nAChR. To address the role of the β2V53 residue in the α1β2γ2L receptor gating, we performed high resolution macroscopic and single-channel recordings. To explore underlying molecular mechanisms a variety of substituting amino acids were investigated: Glutamate and Lysine (different electric charge), Alanine (aliphatic, larger than Valine) and Histidine (same residue as in homologous α1H55). We report that mutation of the β2V53 residue results in alterations of nearly all gating transitions including opening/closing, preactivation and desensitization. A dramatic gating impairment was observed for glutamate substitution (β2V53E) but β2V53K mutation had a weak effect. The impact of histidine substitution was also small while β2V53A markedly affected the receptor but to a smaller extent than β2V53E. Considering available structures in desensitized and bicuculline blocked shut states we propose that strongly detrimental effect of β2V53E mutation on receptor activation results from electrostatic interaction between the glutamate and β2K274 on the loop M2-M3 which stabilizes the receptor in the shut state. We conclude that β2V53 is strongly involved in mechanisms underlying the receptor gating.
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Affiliation(s)
- Karol Kłopotowski
- Wroclaw Medical University, Department of Biophysics and Neuroscience, Chałubińskiego 3a, Wrocław, Dolnośląskie, PL 50-368, Poland.
| | - Michał A Michałowski
- Wroclaw Medical University, Department of Biophysics and Neuroscience, Chałubińskiego 3a, Wrocław, Dolnośląskie, PL 50-368, Poland
| | - Michalina Gos
- Wroclaw Medical University, Department of Biophysics and Neuroscience, Chałubińskiego 3a, Wrocław, Dolnośląskie, PL 50-368, Poland; University of Wroclaw, Department of Molecular Physiology and Neurobiology, Sienkiewicza 21, Wrocław, Dolnośląskie, Pl 50-335, Poland
| | - Daniela Mosiądz
- Wroclaw Medical University, Department of Biophysics and Neuroscience, Chałubińskiego 3a, Wrocław, Dolnośląskie, PL 50-368, Poland
| | - Marta M Czyżewska
- Wroclaw Medical University, Department of Biophysics and Neuroscience, Chałubińskiego 3a, Wrocław, Dolnośląskie, PL 50-368, Poland
| | - Jerzy W Mozrzymas
- Wroclaw Medical University, Department of Biophysics and Neuroscience, Chałubińskiego 3a, Wrocław, Dolnośląskie, PL 50-368, Poland; University of Wroclaw, Department of Molecular Physiology and Neurobiology, Sienkiewicza 21, Wrocław, Dolnośląskie, Pl 50-335, Poland.
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Sharma D, Tripathi M, Doddamani R, Sharma MC, Lalwani S, Sarat Chandra P, Banerjee Dixit A, Banerjee J. Correlation of age at seizure onset with GABA A receptor subunit and chloride Co-transporter configuration in Focal cortical dysplasia (FCD). Neurosci Lett 2023; 796:137065. [PMID: 36638954 DOI: 10.1016/j.neulet.2023.137065] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2022] [Revised: 12/23/2022] [Accepted: 01/09/2023] [Indexed: 01/12/2023]
Abstract
Focal cortical dysplasia (FCD) represents a group of malformations of cortical development, which are speculated to be related to early developmental defects in the cerebral cortex. According to dysmature cerebral development hypothesis of FCD altered GABAA receptor function is known to contribute to abnormal neuronal network. Here, we studied the possible association between age at seizure onset in FCD with the subunit configuration of GABAA receptors in resected brain specimens obtained from patients with FCD. We observed a significantly higher ratio of α4/α1 subunit-containing GABAA receptors in patients with early onset (EO) FCD as compared to those with late onset (LO) FCD as is seen during the course of development where α4-containing GABAA receptors expression is high as compared to α1-containing GABAA receptors expression. Likewise, the influx to efflux chloride co-transporter expression of NKCC1/KCC2 was also increased in patients with EO FCD as seen during brain development. In addition, we observed that the ratio of GABA/Glutamate neurotransmitters was lower in patients with EO FCD as compared to that in patients with LO FCD. Our findings suggest altered configuration of GABAA receptors in FCD which could be contributing to aberrant depolarizing GABAergic activity. In particular, we observed a correlation of age at seizure onset in FCD with subunit configuration of GABAA receptors, levels of NKCC1/KCC2 and the ratio of GABA/Glutamate neurotransmitters such that the patients with EO FCD exhibited a more critically modulated GABAergic network.
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Affiliation(s)
- Devina Sharma
- Department of Neurosurgery, All India Institute of Medical Sciences, New Delhi, India
| | - Manjari Tripathi
- Department of Neurology, All India Institute of Medical Sciences, New Delhi, India
| | - Ramesh Doddamani
- Department of Neurosurgery, All India Institute of Medical Sciences, New Delhi, India
| | - M C Sharma
- Department of Pathology, All India Institute of Medical Sciences, New Delhi, India
| | - Sanjeev Lalwani
- Department of Forensic Medicine and Toxicology, All India Institute of Medical Sciences, New Delhi, India
| | - P Sarat Chandra
- Department of Neurosurgery, All India Institute of Medical Sciences, New Delhi, India
| | - Aparna Banerjee Dixit
- Dr. B.R Ambedkar Center for Biomedical Research, University of Delhi, New Delhi, India
| | - Jyotirmoy Banerjee
- Department of Biophysics, All India Institute of Medical Sciences, New Delhi, India.
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Khodaei S, Wang DS, Lee Y, Chung W, Orser BA. Sevoflurane and lipopolysaccharide-induced inflammation differentially affect γ-aminobutyric acid type A receptor-mediated tonic inhibition in the hippocampus of male mice. Br J Anaesth 2023; 130:e7-e10. [PMID: 36336522 DOI: 10.1016/j.bja.2022.09.013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2022] [Accepted: 09/14/2022] [Indexed: 11/06/2022] Open
Affiliation(s)
- Shahin Khodaei
- Department of Physiology, University of Toronto, Toronto, ON, Canada
| | - Dian-Shi Wang
- Department of Physiology, University of Toronto, Toronto, ON, Canada
| | - Yulim Lee
- Department of Medical Science, Chungnam National University School of Medicine, Daejeon, Republic of Korea
| | - Woosuk Chung
- Department of Physiology, University of Toronto, Toronto, ON, Canada; Department of Medical Science, Chungnam National University School of Medicine, Daejeon, Republic of Korea; Department of Anesthesia and Pain Medicine, Chungnam National University School of Medicine, Daejeon, Republic of Korea
| | - Beverley A Orser
- Department of Physiology, University of Toronto, Toronto, ON, Canada; Department of Anesthesiology & Pain Medicine, University of Toronto, Toronto, ON, Canada; Department of Anesthesia, Sunnybrook Health Sciences Centre, Toronto, ON, Canada.
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11
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Shafiee Z, Karami L, Akbari M, Rezaee E, Maaza M, Tabatabai SA, Karimi G. Insights into the molecular mechanism of triazolopyrimidinone derivatives effects on the modulation of α 1β 2γ 2 subtype of GABA A receptor: An in silico approach. Arch Biochem Biophys 2022; 729:109380. [PMID: 36027937 DOI: 10.1016/j.abb.2022.109380] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2022] [Revised: 07/30/2022] [Accepted: 08/18/2022] [Indexed: 11/25/2022]
Abstract
Due to the importance of benzodiazepine drugs in clinical practice, such as the treatment of anxiety disorders, depression, and insomnia and the side effects of classical benzodiazepines, the study of new benzodiazepine agonists has received much attentions. In this work, we used in silico methods to explore the molecular mechanism of 1,2,4-triazolo [1,5--a] pyrimidinone derivatives in the modulation of α1β2γ2 subtype of GABAA receptor. To this aim, molecular docking, molecular dynamics simulation (MD), post-MD analysis, binding free energy calculation, and prediction of ADME properties were performed. Results showed that all new compounds have a better binding affinity for the Benzodiazepine (BZD) site of the receptor than diazepam and compound 4c had the highest affinity among them. Moreover, a good agreement was observed between the calculated ΔGbinding and experimental IC50 values. Also, we noticed that residues in loop regions (particularly loop C and D-F in α1 and γ2 subunits, respectively) forming BZD binding site, take part in forming several H-bonds between the agonists and the receptor. Ser205, Thr207, Tyr160, and His102 of α1 subunit and Thr207 of γ2 subunit are mainly involved in forming H-bonds. Also, the orientation of agonists in the BZD binding site leads to π-π interactions with hydrophobic residues in loops A-F. Based on the DCCM analysis, the correlated motions in the γ2 subunit residues are greater than those of α1 subunit residues. Further, predicted ADME results indicated that all agonists meet the criteria. The triplicate MD simulation showed the reproducibility of the results and strengthened the study. Our results provide a comprehensive insight into the receptor-agonist interactions and clues for designing future BZD agonists.
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Affiliation(s)
- Zohreh Shafiee
- Department of Cell and Molecular Biology, Faculty of Biological Sciences, Kharazmi University, Tehran, Iran
| | - Leila Karami
- Department of Cell and Molecular Biology, Faculty of Biological Sciences, Kharazmi University, Tehran, Iran.
| | - Mahmood Akbari
- UNESCO-UNISA Africa Chair in Nanosciences/Nanotechnology, College of Graduate Studies, University of South Africa (UNISA), Muckleneuk Ridge, P.O. Box 392, Pretoria, South Africa; Nanosciences African Network (NANOAFNET), iThemba LABS-National Research Foundation, Old Faure Road, 7129, Somerset West, South Africa
| | - Elham Rezaee
- Department of Pharmaceutical Chemistry, School of Pharmacy, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Malik Maaza
- UNESCO-UNISA Africa Chair in Nanosciences/Nanotechnology, College of Graduate Studies, University of South Africa (UNISA), Muckleneuk Ridge, P.O. Box 392, Pretoria, South Africa; Nanosciences African Network (NANOAFNET), iThemba LABS-National Research Foundation, Old Faure Road, 7129, Somerset West, South Africa
| | - Sayyed Abbas Tabatabai
- Department of Pharmaceutical Chemistry, School of Pharmacy, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Gilda Karimi
- Department of Cell and Molecular Biology, Faculty of Biological Sciences, Kharazmi University, Tehran, Iran
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Al-Absi AR, Thambiappa SK, Khan AR, Glerup S, Sanchez C, Landau AM, Nyengaard JR. Df(h22q11)/+ mouse model exhibits reduced binding levels of GABA A receptors and structural and functional dysregulation in the inhibitory and excitatory networks of hippocampus. Mol Cell Neurosci 2022; 122:103769. [PMID: 35988854 DOI: 10.1016/j.mcn.2022.103769] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2022] [Revised: 08/11/2022] [Accepted: 08/14/2022] [Indexed: 11/17/2022] Open
Abstract
The 22q11.2 hemizygous deletion confers high risk for multiple neurodevelopmental disorders. Inhibitory signaling, largely regulated through GABAA receptors, is suggested to serve a multitude of brain functions that are disrupted in the 22q11.2 deletion syndrome. We investigated the putative deficit of GABAA receptors and the potential substrates contributing to the inhibitory and excitatory dysregulations in hippocampal networks of the Df(h22q11)/+ mouse model of the 22q11.2 hemizygous deletion. The Df(h22q11)/+ mice exhibited impairments in several hippocampus-related functional domains, represented by impaired spatial memory and sensory gating functions. Autoradiography using the [3H]muscimol tracer revealed a significant reduction in GABAA receptor binding in the CA1 and CA3 subregions, together with a loss of GAD67+ interneurons in CA1 of Df(h22q11)/+ mice. Furthermore, electrophysiology recordings exhibited significantly higher neuronal activity in CA3, in response to the GABAA receptor antagonist, bicuculline, as compared with wild type mice. Density and volume of dendritic spines in pyramidal neurons were reduced and Sholl analysis also showed a reduction in the complexity of basal dendritic tree in CA1 and CA3 subregions of Df(h22q11)/+ mice. Overall, our findings demonstrate that hemizygous deletion in the 22q11.2 locus leads to dysregulations in the inhibitory circuits, involving reduced binding levels of GABAA receptors, in addition to functional and structural modulations of the excitatory networks of hippocampus.
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Affiliation(s)
- Abdel-Rahman Al-Absi
- Center for Molecular Morphology, Section for Stereology and Microscopy, Department of Clinical Medicine, Aarhus University, Denmark; Department of Pathology, Aarhus University Hospital, Denmark.
| | - Sakeerthi Kethees Thambiappa
- Center for Molecular Morphology, Section for Stereology and Microscopy, Department of Clinical Medicine, Aarhus University, Denmark; Department of Pathology, Aarhus University Hospital, Denmark.
| | - Ahmad Raza Khan
- Centre of Biomedical Research (CBMR), SGPGIMS Campus, Lucknow, India.
| | - Simon Glerup
- Department of Biomedicine, Aarhus University, Denmark.
| | - Connie Sanchez
- Translational Neuropsychiatry Unit, Aarhus University, Denmark.
| | - Anne M Landau
- Translational Neuropsychiatry Unit, Aarhus University, Denmark; Department of Nuclear Medicine and PET Centre, Aarhus University Hospital, Denmark.
| | - Jens R Nyengaard
- Center for Molecular Morphology, Section for Stereology and Microscopy, Department of Clinical Medicine, Aarhus University, Denmark; Department of Pathology, Aarhus University Hospital, Denmark.
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Ihara M, Tanaka K, Kai K, Hayashi H, Matsuda K. Competitive chrodrimanin B interactions with rat brain GABA A receptors revealed by radioligand binding assays. Pestic Biochem Physiol 2022; 183:105074. [PMID: 35430068 DOI: 10.1016/j.pestbp.2022.105074] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/30/2021] [Revised: 02/25/2022] [Accepted: 03/01/2022] [Indexed: 06/14/2023]
Abstract
Meroterpenoid compounds chrodrimanins produced by Talaromyces sp. YO-2 have been shown to act as competitive antagonists of silkworm larval GABAA receptors using electrophysiology, yet no further evidence has been provided to support such an action. We have investigated the actions of chrodrimanin B on rat brain GABAA receptors by binding assays with non-competitive ligand of GABAA receptors [3H]EBOB and competitive ligands [3H]gabazine and [3H]muscimol. Chrodrimanin B did not significantly affect the binding of [3H]EBOB while reducing the binding of [3H]gabazine and [3H]muscimol to the rat membrane preparations. Chrodrimanin B increased the dissociation constant Kd of [3H]gabazine and [3H]muscimol without significantly affecting the maximum binding, pointing to competitive interactions of chrodrimanin B with rat GABAA receptors in support of our previous observation that the compound acts as a competitive antagonist on the silkworm larval GABA receptor.
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Affiliation(s)
- Makoto Ihara
- Department of Applied Biological Chemistry, Faculty of Agriculture, Kindai University 3327-204 Nakamachi, Nara 631-8505, Japan
| | - Keiji Tanaka
- Department of Applied Biological Chemistry, Faculty of Agriculture, Kindai University 3327-204 Nakamachi, Nara 631-8505, Japan
| | - Kenji Kai
- Graduate School of Life and Environmental Sciences, Osaka Prefecture University, Sakai, Osaka, 599-8531, Japan
| | - Hideo Hayashi
- Graduate School of Life and Environmental Sciences, Osaka Prefecture University, Sakai, Osaka, 599-8531, Japan
| | - Kazuhiko Matsuda
- Department of Applied Biological Chemistry, Faculty of Agriculture, Kindai University 3327-204 Nakamachi, Nara 631-8505, Japan; Agricultural Technology and Innovation Research Institute, Kindai University, 3327-204 Nakamachi, Nara 631-8505, Japan.
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Stefano MED, Ferretti V, Mozzetta C. Synaptic alterations as a neurodevelopmental trait of Duchenne muscular dystrophy. Neurobiol Dis 2022; 168:105718. [PMID: 35390481 DOI: 10.1016/j.nbd.2022.105718] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2021] [Revised: 03/28/2022] [Accepted: 03/29/2022] [Indexed: 01/14/2023] Open
Abstract
Dystrophinopaties, e.g., Duchenne muscular dystrophy (DMD), Becker muscular dystrophy and X-linked dilated cardiomyopathy are inherited neuromuscular diseases, characterized by progressive muscular degeneration, which however associate with a significant impact on general system physiology. The more severe is the pathology and its diversified manifestations, the heavier are its effects on organs, systems, and tissues other than muscles (skeletal, cardiac and smooth muscles). All dystrophinopaties are characterized by mutations in a single gene located on the X chromosome encoding dystrophin (Dp427) and its shorter isoforms, but DMD is the most devasting: muscular degenerations manifests within the first 4 years of life, progressively affecting motility and other muscular functions, and leads to a fatal outcome between the 20s and 40s. To date, after years of studies on both DMD patients and animal models of the disease, it has been clearly demonstrated that a significant percentage of DMD patients are also afflicted by cognitive, neurological, and autonomic disorders, of varying degree of severity. The anatomical correlates underlying neural functional damages are established during embryonic development and the early stages of postnatal life, when brain circuits, sensory and motor connections are still maturing. The impact of the absence of Dp427 on the development, differentiation, and consolidation of specific cerebral circuits (hippocampus, cerebellum, prefrontal cortex, amygdala) is significant, and amplified by the frequent lack of one or more of its lower molecular mass isoforms. The most relevant aspect, which characterizes DMD-associated neurological disorders, is based on morpho-functional alterations of selective synaptic connections within the affected brain areas. This pathological feature correlates neurological conditions of DMD to other severe neurological disorders, such as schizophrenia, epilepsy and autistic spectrum disorders, among others. This review discusses the organization and the role of the dystrophin-dystroglycan complex in muscles and neurons, focusing on the neurological aspect of DMD and on the most relevant morphological and functional synaptic alterations, in both central and autonomic nervous systems, described in the pathology and its animal models.
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Affiliation(s)
- Maria Egle De Stefano
- Department of Biology and Biotechnology "Charles Darwin", Sapienza University of Rome, 00185 Rome, Italy; Center for Research in Neurobiology Daniel Bovet, Sapienza University of Rome, 00185 Rome, Italy.
| | - Valentina Ferretti
- Department of Biology and Biotechnology "Charles Darwin", Sapienza University of Rome, 00185 Rome, Italy; Center for Research in Neurobiology Daniel Bovet, Sapienza University of Rome, 00185 Rome, Italy
| | - Chiara Mozzetta
- Institute of Molecular Biology and Pathology (IBPM), National Research Council (CNR) of Italy c/o Department of Biology and Biotechnology "Charles Darwin", Sapienza University of Rome, 00185 Rome, Italy
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Xu L, Liu MZ, Yang YY, Wang Y, Hua XX, Du LX, Zhu JY, Shen Y, Wang YQ, Zhang L, Mi WL, Mu D. Geraniol enhances inhibitory inputs to the paraventricular thalamic nucleus and induces sedation in mice. Phytomedicine 2022; 98:153965. [PMID: 35144136 DOI: 10.1016/j.phymed.2022.153965] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/29/2021] [Revised: 12/31/2021] [Accepted: 01/25/2022] [Indexed: 06/14/2023]
Abstract
BACKGROUND Plant extracts with sedative effects have a long history of clinical use for treating insomnia and epilepsy. Geraniol (GE), a plant-derived acyclic monoterpene, reduces locomotion and prolongs barbiturate-induced anesthesia in rats. However, the mechanisms of GE in sedation remain elusive. PURPOSE This study aimed to investigate the mechanisms of GE in sedation in mice. METHODS GE was administered systemically by nebulization and intraperitoneal injection. Open field tests, acute seizure tests, and electroencephalogram (EEG) recordings were performed to examine the sedative effects of GE in mice. The time of loss of the righting reflex and return of the righting reflex were recorded in anesthesia experiments to examine the effect of GE on anesthesia. In vitro c-Fos staining and in vivo fiber photometry recordings were performed to detect the activity change of the paraventricular thalamic nucleus (PVT). Microinjection of GE into PVT and related behavioral tests were performed to confirm that PVT was a critical target for GE. Whole-cell recordings were performed to dissect the effects of GE on PVT neurons via GABAA receptors. Molecular docking was performed to examine the interaction between GE and GABAA receptor subunits. RESULTS We found that GE reduced locomotion, relieved acute seizures, altered the EEG, and facilitated general anesthesia in mice. Next, we found that GE decreased c-Fos expression and suppressed the calcium activity in PVT. Microinjection of GE into PVT reduced locomotion and facilitated anesthesia. Furthermore, electrophysiology results showed that GE induced dramatic membrane hyperpolarization and suppressed the activity of PVT neurons, mainly by prolonging spontaneous inhibitory postsynaptic currents and inducing tonic inhibitory currents. Molecular docking results indicated that the β3 subunit might be a potential target for GE. CONCLUSION By combined using behavioral tests, immunohistochemistry, calcium recording, and electrophysiology, we systematically revealed that GE inhibits PVT and induces sedation in mice. Essential oils have long been considered part of traditional medicine, and they are playing a critical role in aromatherapy. Since GE has a comparatively ideal safety property and multiple delivery methods, GE has great application potential in aromatherapy. Our study also provides a potential candidate for further development of sedatives and anaesthetics.
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Affiliation(s)
- Ling Xu
- Department of Anesthesiology, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 201620, China
| | - Ming-Zhe Liu
- Department of Respiratory, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou 510120, China
| | - Ya-Yue Yang
- Department of Integrative Medicine and Neurobiology, School of Basic Medical Science, Institutes of Integrative Medicine, Institutes of Brain Science, Medical College, Fudan University, Shanghai 200032, China
| | - Yan Wang
- Department of Anesthesiology, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 201620, China
| | - Xiao-Xiao Hua
- The First Rehabilitation Hospital of Shanghai, Tongji University School of Medicine, Shanghai 200090, China
| | - Li-Xia Du
- Department of Integrative Medicine and Neurobiology, School of Basic Medical Science, Institutes of Integrative Medicine, Institutes of Brain Science, Medical College, Fudan University, Shanghai 200032, China
| | - Jian-Yu Zhu
- Department of Integrative Medicine and Neurobiology, School of Basic Medical Science, Institutes of Integrative Medicine, Institutes of Brain Science, Medical College, Fudan University, Shanghai 200032, China
| | - Yang Shen
- Department of Anesthesiology, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 201620, China
| | - Yan-Qing Wang
- Department of Integrative Medicine and Neurobiology, School of Basic Medical Science, Institutes of Integrative Medicine, Institutes of Brain Science, Medical College, Fudan University, Shanghai 200032, China; Shanghai Key Laboratory for Acupuncture Mechanism and Acupoint Function, Fudan University, Shanghai 200433, China
| | - Ling Zhang
- The First Rehabilitation Hospital of Shanghai, Tongji University School of Medicine, Shanghai 200090, China
| | - Wen-Li Mi
- Department of Integrative Medicine and Neurobiology, School of Basic Medical Science, Institutes of Integrative Medicine, Institutes of Brain Science, Medical College, Fudan University, Shanghai 200032, China; Shanghai Key Laboratory for Acupuncture Mechanism and Acupoint Function, Fudan University, Shanghai 200433, China.
| | - Di Mu
- SUSTech Center for Pain Medicine, School of Medicine, Southern University of Science and Technology, Shenzhen 518055, China; Department of Anesthesiology, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 201620, China.
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Chandler CM, Reeves-Darby J, Jones SA, Li G, Rahman MT, Cook JM, Platt DM. Modulation of relapse-like drinking in male Sprague-Dawley rats by ligands targeting the α5GABA A receptor. Neuropharmacology 2021; 199:108785. [PMID: 34509495 DOI: 10.1016/j.neuropharm.2021.108785] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2021] [Revised: 08/26/2021] [Accepted: 09/04/2021] [Indexed: 11/20/2022]
Abstract
Preclinical evidence suggests a key role for GABAA receptors containing the α5 subunit (i.e., α5GABAA receptors) in the abuse-related effects of alcohol, including the reinforcing and discriminative stimulus effects, as well as cue-induced alcohol-seeking behavior. However, the contribution of this GABAA receptor subtype to relapse-like drinking behavior remains unknown. The present study evaluated the capacity of ligands targeting α5GABAA receptors to modulate the alcohol deprivation effect (ADE), a model of relapse-like drinking. Groups of Sprague-Dawley rats underwent repeated cycles of long-term access to alcohol solutions (5%, 10%, 20% v/v) and water in the home cage followed by water only deprivation periods. Upon evidence that the ADE could be reliably expressed across cycles, drug treatment was initiated. One group received the α5GABAA receptor-preferring agonist QH-ii-066 and the other group received the α5GABAA receptor-selective inverse agonist L-655,708. At the end of ADE testing, rats underwent testing in the elevated zero maze under vehicle or L-655,708 treatment for assessment of anxiety-like behavior. The ADE was reliably expressed across repeated cycles of alcohol access/deprivation in a subset of rats. Low doses of QH-ii-066 enhanced expression of the ADE; whereas, L-655,708 dose-dependently inhibited expression of the ADE. L-655,708 did not engender anxiogenic effects in the elevated zero maze under the conditions evaluated. These findings suggest a key role for α5GABAA receptor mechanisms in relapse-like drinking. Moreover, they suggest that α5GABAA receptors may represent a novel pharmacological target for the development of medications to prevent or reduce alcohol relapse.
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Hacke ACM, Miyoshi E, Marques JA, Pereira RP. Cymbopogon citratus (DC.) Stapf, citral and geraniol exhibit anticonvulsant and neuroprotective effects in pentylenetetrazole-induced seizures in zebrafish. J Ethnopharmacol 2021; 275:114142. [PMID: 33910044 DOI: 10.1016/j.jep.2021.114142] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/23/2020] [Revised: 02/21/2021] [Accepted: 04/21/2021] [Indexed: 06/12/2023]
Abstract
ETHNOPHARMACOLOGICAL RELEVANCE Cymbopogon citratus (DC.) Stapf (C. citratus) is consumed as an infusion in folk medicine due to its pharmacological properties and action in the central nervous system. Epilepsy is a neurological disorder that affects millions of people. Since the currently available antiepileptic drugs often cause undesirable side effects, new alternative therapeutic strategies based on medicinal plants have been proposed. AIM OF THE STUDY This study aimed to investigate the anticonvulsant and neuroprotective effects of C. citratus essential oil (EO) and hydroalcoholic extract (E1) from its leaves, as well as of its related compounds citral (CIT) and geraniol (GER) against the effects of pentylenetetrazole (PTZ) induced seizures in zebrafish (Danio rerio). MATERIALS AND METHODS To evaluate the anticonvulsant properties of the samples, adult animals were pre-treated (by immersion) and subsequently exposed to PTZ solution. The involvement of GABAA receptors in the antiepileptic effects was investigated by the coadministration of flumazenil (FMZ), a known GABAA receptor antagonist. Oxidative stress markers malondialdehyde (MDA), glutathione (GSH), catalase (CAT) and nitric oxide (NO) were assessed in zebrafish brain homogenates after PTZ exposure. RESULTS All samples increased the latency time for the first seizure, which was reduced when animals were pretreated with FMZ, suggesting the involvement of GABAA receptors in the observed properties. The association between CIT and GER at the lowest concentration studied showed a synergistic effect on the anticonvulsant activity. Decreases in MDA and NO levels and increases in GSH and CAT levels in the brain of treated animals suggested the neuroprotective effect of the compounds investigated. CONCLUSIONS Our results proved that C. citratus EO, E1, CIT and GER have anticonvulsant effects in zebrafish and could be used as a promising adjuvant therapeutic strategy for epilepsy treatment. Furthermore, zebrafish demonstrated to be an alternative animal model of epilepsy to evaluate the anticonvulsant and neuroprotective effects of C. citratus.
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Affiliation(s)
| | - Edmar Miyoshi
- Departamento de Ciências Farmacêuticas, Universidade Estadual de Ponta Grossa, UEPG, Ponta Grossa, Brazil.
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Kłopotowski K, Czyżewska MM, Mozrzymas JW. Glycine substitution of α1F64 residue at the loop D of GABA A receptor impairs gating - Implications for importance of binding site-channel gate linker rigidity. Biochem Pharmacol 2021; 192:114668. [PMID: 34216603 DOI: 10.1016/j.bcp.2021.114668] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2021] [Revised: 06/27/2021] [Accepted: 06/28/2021] [Indexed: 12/29/2022]
Abstract
GABAA receptors (GABAARs) play a crucial role in mediating inhibition in adult mammalian brains. In the recent years, an impressive progress in revealing the static structure of GABAARs was achieved but the molecular mechanisms underlying their conformational transitions remain elusive. Phenylalanine 64 (α1F64) is located at the loop D of the orthosteric binding site of GABAAR and was found to directly interact with GABA molecule. Mutations of α1F64 were demonstrated to affect not only binding but also some gating properties. Loop D is a rigid β strand which seems to be particularly suitable to convey activatory signaling from the ligand binding site (LBS) to the gate at the channel pore. To test this scenario, we have investigated the substitution of α1F64 with glycine, the smallest amino acid, widely recognized as a rigidity "reducer" of protein structures. To this end, we assessed the impact of the α1F64G mutation in the α1β2γ2L type of GABAARs on gating properties by analyzing both macroscopic responses to rapid agonist applications and single-channel currents. We found that this substitution dramatically altered all gating features of the receptor (opening/closing, preactivation and desensitization) which contrasts with markedly weaker effects of previously considered substitutions (α1F64L and α1F64A). In particular, α1F64G mutation practically abolished the desensitization process. At the same time, the α1F64G mutant maintained gating integrity manifested as single-channel activity in the form of clusters. We conclude that rigidity of the loop D plays a crucial role in conveying the activation signal from the LBS to the channel gate.
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Affiliation(s)
- Karol Kłopotowski
- Wroclaw Medical University, Department of Biophysics and Neuroscience, Chalubinskiego 3A, Wroclaw, Dolnośląskie PL 50-368, +48 71 784 15 51, Poland.
| | - Marta M Czyżewska
- Wroclaw Medical University, Department of Biophysics and Neuroscience, Chalubinskiego 3A, Wroclaw, Dolnośląskie PL 50-368, +48 71 784 15 51, Poland
| | - Jerzy W Mozrzymas
- Wroclaw Medical University, Department of Biophysics and Neuroscience, Chalubinskiego 3A, Wroclaw, Dolnośląskie PL 50-368, +48 71 784 15 51, Poland.
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Dong L, Li G, Gao Y, Lin L, Cao XB, Zheng Y. Exploring the Inhibitory Effect of Low-frequency Magnetic Fields on Epileptiform Discharges in Juvenile Rat Hippocampus. Neuroscience 2021; 467:1-15. [PMID: 34033871 DOI: 10.1016/j.neuroscience.2021.05.016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2020] [Revised: 05/12/2021] [Accepted: 05/13/2021] [Indexed: 10/01/2022]
Abstract
Stimulation with a low frequency electromagnetic field (LF-EMF) has proven to represent a powerful method for the suppression of seizures, as demonstrated in select clinical and laboratory studies. However, the mechanism by which LF-EMF suppresses seizures remains unclear. The purpose of the present study was to explore the modulatory effect of LF-EMF on epileptiform discharges (EDs) using rat hippocampal slices and investigate the underlying mechanisms that mediate these effects. EDs in hippocampal slices was induced by magnesium-free (zero-Mg2+) artificial cerebrospinal fluid (ACSF) and recorded using an in vitro micro-electrode array (MEA). A small sub-decimeter coil was designed and incorporated in a flexible magnetic stimulation device that allowed electromagnetic fields with different parameters to be delivered to slices. After a stable ED event was recorded, magnetic fields of 0.5 Hz (30 min) with a magnetic intensity of 0.13 mT (5 Vpp voltage input) and 0.25 mT (20 Vpp voltage input) were applied. The results indicated that a high-amplitude 0.5 Hz magnetic field could lead to persistent suppression of ictal discharges (IDs), while low-amplitude magnetic fields did not influence IDs. The persistent suppression of complex ED was prevented if the magnetic fields were applied in the presence of 10 μmol/L bicuculline (BIC), a γ-aminobutyric acid type A (GABAA) receptor antagonist, while the application of BIC subsequent to a magnetic field application led to the reappearance of ID. The addition of BIC resulted in EDs that had previously been inhibited by magnetic fields, reappearing. Low-frequency magnetic stimulation was able to inhibit the conversion from interictal discharges (IIDs) or preictal discharges (PIDs) to IDs. This suppression was attributed to the modulation of GABAA receptor activity.
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Affiliation(s)
- Lei Dong
- State Key Laboratory of Precision Measurement Technology and Instruments, Tianjin University, Tianjin 300072, China; Tianjin Key Laboratory of Biomedical Detecting Techniques & Instruments, Tianjin University, Tianjin 300072, China
| | - Gang Li
- State Key Laboratory of Precision Measurement Technology and Instruments, Tianjin University, Tianjin 300072, China; Tianjin Key Laboratory of Biomedical Detecting Techniques & Instruments, Tianjin University, Tianjin 300072, China
| | - Yang Gao
- School of Information Technology and Electrical Engineering, The University of Queensland, St Lucia, Brisbane, Queensland 4072, Australia
| | - Ling Lin
- State Key Laboratory of Precision Measurement Technology and Instruments, Tianjin University, Tianjin 300072, China; Tianjin Key Laboratory of Biomedical Detecting Techniques & Instruments, Tianjin University, Tianjin 300072, China
| | - Xue-Bin Cao
- Department of Cardiology, 252 Hospital of PLA, Baoding, Hebei 071000, China.
| | - Yu Zheng
- School of Life Sciences, Tiangong University, Tianjin 300387, China.
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Shimizu Y, Shimizu T, Zou S, Ono H, Hata Y, Yamamoto M, Aratake T, Shimizu S, Higashi Y, Karashima T, Saito M. Stimulation of brain α7-nicotinic acetylcholine receptors suppresses the rat micturition through brain GABAergic receptors. Biochem Biophys Res Commun 2021; 548:84-90. [PMID: 33636639 DOI: 10.1016/j.bbrc.2021.02.051] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2021] [Accepted: 02/12/2021] [Indexed: 12/15/2022]
Abstract
Brain nicotinic acetylcholine receptors (nAChRs) reportedly suppress the micturition, but the mechanisms responsible for this suppression remain unclear. We previously reported that intracerebroventricularly administered (±)-epibatidine (non-selective nAChR agonist) activated the sympatho-adrenomedullary system, which can affect the micturition. Therefore, we investigated (1) whether intracerebroventricularly administered (±)-epibatidine-induced effects on the micturition were dependent on the sympatho-adrenomedullary system, and (2) brain nAChR subtypes involved in the (±)-epibatidine-induced effects in urethane-anesthetized male Wistar rats. Plasma noradrenaline and adrenaline (catecholamines) were measured just before and 5 min after (±)-epibatidine administration. Evaluation of urodynamic parameters, intercontraction intervals (ICI) and maximal voiding pressure (MVP) by cystometry was started 1 h before (±)-epibatidine administration or intracerebroventricular pretreatment with other drugs and continued 1 h after (±)-epibatidine administration. Intracerebroventricularly administered (±)-epibatidine elevated plasma catecholamines and prolonged ICI without affecting MVP, and these changes were suppressed by intracerebroventricularly pretreated mecamylamine (non-selective nAChR antagonist). Acute bilateral adrenalectomy abolished the (±)-epibatidine-induced elevation of plasma catecholamines, but had no effect on the (±)-epibatidine-induced ICI prolongation. The latter was suppressed by intracerebroventricularly pretreated methyllycaconitine (selective α7-nAChR antagonist), SR95531 (GABAA antagonist), and SCH50911 (GABAB antagonist), but not by dihydro-β-erythroidine (selective α4β2-nAChR antagonist). Intracerebroventricularly administered PHA568487 (selective α7-nAChR agonist) prolonged ICI without affecting MVP, similar to (±)-epibatidine. These results suggest that stimulation of brain α7-nAChRs suppresses the rat micturition through brain GABAA/GABAB receptors, independently of the sympatho-adrenomedullary outflow modulation.
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Affiliation(s)
- Yohei Shimizu
- Department of Pharmacology, Kochi Medical School, Kochi University, Nankoku, Kochi, 783-8505, Japan; Center for Innovative and Translational Medicine, Kochi Medical School, Kochi University, Nankoku, Kochi, 783-8505, Japan
| | - Takahiro Shimizu
- Department of Pharmacology, Kochi Medical School, Kochi University, Nankoku, Kochi, 783-8505, Japan.
| | - Suo Zou
- Department of Pharmacology, Kochi Medical School, Kochi University, Nankoku, Kochi, 783-8505, Japan
| | - Hideaki Ono
- Department of Pharmacology, Kochi Medical School, Kochi University, Nankoku, Kochi, 783-8505, Japan; Center for Innovative and Translational Medicine, Kochi Medical School, Kochi University, Nankoku, Kochi, 783-8505, Japan
| | - Yurika Hata
- Department of Pharmacology, Kochi Medical School, Kochi University, Nankoku, Kochi, 783-8505, Japan; Center for Innovative and Translational Medicine, Kochi Medical School, Kochi University, Nankoku, Kochi, 783-8505, Japan
| | - Masaki Yamamoto
- Department of Pharmacology, Kochi Medical School, Kochi University, Nankoku, Kochi, 783-8505, Japan
| | - Takaaki Aratake
- Department of Pharmacology, Kochi Medical School, Kochi University, Nankoku, Kochi, 783-8505, Japan; Japan Society for the Promotion of Science, Japan
| | - Shogo Shimizu
- Department of Pharmacology, Kochi Medical School, Kochi University, Nankoku, Kochi, 783-8505, Japan
| | - Youichirou Higashi
- Department of Pharmacology, Kochi Medical School, Kochi University, Nankoku, Kochi, 783-8505, Japan
| | - Takashi Karashima
- Department of Urology, Kochi Medical School, Kochi University, Nankoku, Kochi, 783-8505, Japan
| | - Motoaki Saito
- Department of Pharmacology, Kochi Medical School, Kochi University, Nankoku, Kochi, 783-8505, Japan
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21
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Abstract
Epilepsy is a neurological condition characterized by synchronous neuronal oscillations (seizures) in the electroencephalogram. Seizures are classified in focal or generalized (depending on the brain territory interested during seizures), and in convulsive and/or not convulsive (depending on the presence or not of involuntary movements). The current pharmacological treatments are mainly based on GABA modulation although different neurotransmitters are also involved in epilepsy, including serotonin. However despite much extensive progress in the understanding of epilepsy mechanisms, still, a percentage of people with epilepsy are pharmaco-resistant calling for the need for new therapeutic targets. Here we review preclinical and human evidence showing that serotonin modulates epilepsy that this likely happens via a major modulation/interaction with GABA.
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Affiliation(s)
- Gabriele Deidda
- Laboratory of Neurophysiology, Department of Physiology and Biochemistry, Faculty of Medicine and Surgery, University of Malta, Msida, Malta.
| | - Vincenzo Crunelli
- Laboratory of Neurophysiology, Department of Physiology and Biochemistry, Faculty of Medicine and Surgery, University of Malta, Msida, Malta; Neuroscience Division, School of Biosciences, Cardiff University, Cardiff, United Kingdom
| | - Giuseppe Di Giovanni
- Laboratory of Neurophysiology, Department of Physiology and Biochemistry, Faculty of Medicine and Surgery, University of Malta, Msida, Malta; Neuroscience Division, School of Biosciences, Cardiff University, Cardiff, United Kingdom
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22
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El-Mallakh RS, Ali Z. Extra-synaptic modulation of GABA A and efficacy in bipolar disorder. Med Hypotheses 2021; 147:110501. [PMID: 33515862 DOI: 10.1016/j.mehy.2021.110501] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2020] [Revised: 12/22/2020] [Accepted: 01/08/2021] [Indexed: 11/27/2022]
Abstract
BACKGROUND Bipolar disorder type I is a severe psychiatric condition that leads to significant morbidity and mortality and whose treatment remains suboptimal. Its pathophysiology involves disturbance in the control of ionic fluxes so that when patients are either manic or depressed, the resting membrane potential of neurons is more depolarized than normal. Available mood stabilizers have a shared mechanism of normalizing ion flux by compensating for ionic abnormalities, and normalizing membrane potential. HYPOTHESIS Agents that significantly potentiate extrasynaptic GABAA receptors are expected to be particularly effective in hyperpolarizing resting membrane potential in bipolar patients, thereby normalizing their membrane potential. DISCUSSION New neuroactive steroid-like agents are being tested in humans for depression and insomnia. These agents include brexanolone, ganaxolone, and gaboxadol. Brexanolone has been approved for the treatment of postpartum depression, ganaxolone is being studied for treatment-resistant depression, and gaboxadol development for the treatment of insomnia has been abandoned due to narrow therapeutic index. In addition to the current studies, these agents are expected to have particular efficacy in acute and prophylactic management of bipolar I disorder by hyperpolarizing the resting potential of neurons and antagonizing one of the most reproducible demonstrated biologic abnormalities of this illness.
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Affiliation(s)
- Rif S El-Mallakh
- Mood Disorders Research Program, Depression Center Department of Psychiatry and Behavioral Sciences University of Louisville School of Medicine, 401 East Chestnut Street, Suite 610 Louisville, Kentucky 40202, USA.
| | - Ziad Ali
- Department of Psychiatry, University of Kentucky College of Medicine, The Medical Center of Bowling Green, Bowling Green, KY, USA
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23
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Terejko K, Michałowski MA, Dominik A, Andrzejczak A, Mozrzymas JW. Interaction between GABA A receptor α 1 and β 2 subunits at the N-terminal peripheral regions is crucial for receptor binding and gating. Biochem Pharmacol 2021; 183:114338. [PMID: 33189674 DOI: 10.1016/j.bcp.2020.114338] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2020] [Revised: 11/09/2020] [Accepted: 11/09/2020] [Indexed: 01/08/2023]
Abstract
Pentameric ligand gated ion channels (pLGICs) are crucial in electrochemical signaling but exact molecular mechanisms of their activation remain elusive. So far, major effort focused on the top-down molecular pathway between the ligand binding site and the channel gate. However, recent studies revealed that pLGIC activation is associated with coordinated subunit twisting in the membrane plane. This suggests a key role of intersubunit interactions but the underlying mechanisms remain largely unknown. Herein, we investigated a "peripheral" subunit interface region of GABAA receptor where structural modeling indicated interaction between N-terminal α1F14 and β2F31 residues. Our experiments underscored a crucial role of this interaction in ligand binding and gating, especially preactivation and opening, showing that the intersubunit cross-talk taking place outside (above) the top-down pathway can be strongly involved in receptor activation. Thus, described here intersubunit interaction appears to operate across a particularly long distance, affecting vast portions of the macromolecule.
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24
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Zheng Y, Zhang K, Dong L, Tian C. Study on the mechanism of high-frequency stimulation inhibiting low-Mg 2+-induced epileptiform discharges in juvenile rat hippocampal slices. Brain Res Bull 2020; 165:1-13. [PMID: 32961285 DOI: 10.1016/j.brainresbull.2020.09.008] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2020] [Revised: 09/02/2020] [Accepted: 09/09/2020] [Indexed: 11/29/2022]
Abstract
Study on the mechanism of high-frequency stimulation inhibiting low-Mg2+-induced epileptiform discharges in juvenile rat hippocampal slices High-frequency stimulation (HFS) has been demonstrated to be an effective treatment for inhibiting epilepsy in some clinical and laboratory studies. However, the mechanisms underlying the therapeutic effects of HFS are not yet fully understood. In our present study, epileptiform discharges (EDs) in acutely isolated hippocampal slices of male Sprague-Dawley (SD) juvenile rats induced by low-Mg2+ artificial cerebrospinal fluid (ACSF), and electrical stimulation (square wave, 900 pulses, 50 % duty-cycle, 130 Hz) was performed on the CA3 using concentric bipolar electrodes. EDs of neurons in hippocampal were recorded by multi-electrode arrays (MEA). After stable EDs events had been recorded for at least 20 min, HFS was added, followed by 10 μmol/L gamma-aminobutyric acid type A (GABAA) receptors blocker bicuculline (BIC). The results show that the HFS can increase the discharges frequency of inter-ictal discharges (IIDs) and decrease the duration of ictal discharges (IDs). However, the HFS had no effect on the slices with 10 μmol/L BIC. These results indicated that the GABAA receptors are activated when HFS inhibited EDs, thereby achieving the inhibition of low-Mg2+-induced EDs in slices.
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Affiliation(s)
- Yu Zheng
- School of Life Sciences, Tiangong University, Tianjin, 300387, China.
| | - Kanghui Zhang
- School of Life Sciences, Tiangong University, Tianjin, 300387, China
| | - Lei Dong
- State Key Laboratory of Precision Measurement Technology and Instruments, Tianjin University, Tianjin, 300072, China
| | - Chunxiao Tian
- School of Life Sciences, Tiangong University, Tianjin, 300387, China
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25
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Xu W, Wang L, Yuan XS, Wang TX, Li WX, Qu WM, Hong ZY, Huang ZL. Sevoflurane depresses neurons in the medial parabrachial nucleus by potentiating postsynaptic GABA A receptors and background potassium channels. Neuropharmacology 2020; 181:108249. [PMID: 32931816 DOI: 10.1016/j.neuropharm.2020.108249] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2020] [Revised: 06/23/2020] [Accepted: 07/20/2020] [Indexed: 12/28/2022]
Abstract
Despite persistent clinical use for over 170 years, the neuronal mechanisms by which general anesthetics produce hypnosis remain unclear. Previous studies suggest that anesthetics exert hypnotic effects by acting on endogenous arousal circuits. Recently, it has been shown that the medial parabrachial nucleus (MPB) is a novel wake-promoting component in the dorsolateral pons. However, it is not known whether and how the MPB contributes to anesthetic-induced hypnosis. Here, we investigated the action of sevoflurane, a widely used volatile anesthetic agent that best represents the drug class of halogenated ethers, on MPB neurons in mice. Using in vivo fiber photometry, we found that the population activities of MPB neurons were inhibited during sevoflurane-induced loss of consciousness. Using in vitro whole-cell patch-clamp recordings, we revealed that sevoflurane suppressed the firing rate of MPB neurons in concentration-dependent and reversible manners. At a concentration equal to MAC of hypnosis, sevoflurane potentiated synaptic GABAA receptors (GABAA-Rs), and the inhibitory effect of sevoflurane on the firing rate of MPB neurons was completely abolished by picrotoxin, which is a selective GABAA-R antagonist. At a concentration equivalent to MAC of immobility, sevoflurane directly hyperpolarized MPB neurons and induced a significant decrease in membrane input resistance by increasing a basal potassium conductance. Moreover, pharmacological blockade of GABAA-Rs in the MPB prolongs induction and shortens emergence under sevoflurane inhalation at MAC of hypnosis. These results indicate that sevoflurane inhibits MPB neurons through postsynaptic GABAA-Rs and background potassium channels, which contributes to sevoflurane-induced hypnosis.
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Affiliation(s)
- Wei Xu
- Department of Pharmacology, School of Basic Medical Sciences; State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, and Institutes of Brain Science, Shanghai Medical College of Fudan University, Shanghai, China
| | - Lu Wang
- Department of Pharmacology, School of Basic Medical Sciences; State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, and Institutes of Brain Science, Shanghai Medical College of Fudan University, Shanghai, China
| | - Xiang-Shan Yuan
- Department of Pharmacology, School of Basic Medical Sciences; State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, and Institutes of Brain Science, Shanghai Medical College of Fudan University, Shanghai, China
| | - Tian-Xiao Wang
- Department of Pharmacology, School of Basic Medical Sciences; State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, and Institutes of Brain Science, Shanghai Medical College of Fudan University, Shanghai, China
| | - Wen-Xian Li
- Department of Anesthesiology, The Eye, Ear, Nose and Throat Hospital of Fudan University, Shanghai Medical College of Fudan University, Shanghai, China
| | - Wei-Min Qu
- Department of Pharmacology, School of Basic Medical Sciences; State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, and Institutes of Brain Science, Shanghai Medical College of Fudan University, Shanghai, China
| | - Zong-Yuan Hong
- Laboratory of Quantitative Pharmacology, Department of Pharmacology, Wannan Medical College, Wuhu, China
| | - Zhi-Li Huang
- Department of Pharmacology, School of Basic Medical Sciences; State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, and Institutes of Brain Science, Shanghai Medical College of Fudan University, Shanghai, China.
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26
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Di XJ, Wang YJ, Cotter E, Wang M, Whittsette AL, Han DY, Sangwung P, Brown R, Lynch JW, Keramidas A, Mu TW. Proteostasis Regulators Restore Function of Epilepsy-Associated GABA A Receptors. Cell Chem Biol 2020; 28:46-59.e7. [PMID: 32888501 DOI: 10.1016/j.chembiol.2020.08.012] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2020] [Revised: 08/10/2020] [Accepted: 08/17/2020] [Indexed: 12/19/2022]
Abstract
Proteostasis deficiency in mutated ion channels leads to a variety of ion channel diseases that are caused by excessive endoplasmic reticulum-associated degradation (ERAD) and inefficient membrane trafficking. We investigated proteostasis maintenance of γ-aminobutyric acid type A (GABAA) receptors, the primary mediators of neuronal inhibition in the mammalian central nervous system. We screened a structurally diverse, Food and Drug Administration-approved drug library and identified dinoprost (DNP) and dihydroergocristine (DHEC) as highly efficacious enhancers of surface expression of four epilepsy-causing trafficking-deficient mutant receptors. Furthermore, DNP and DHEC restore whole-cell and synaptic currents by incorporating mutated subunits into functional receptors. Mechanistic studies revealed that both drugs reduce subunit degradation by attenuating the Grp94/Hrd1/Sel1L/VCP-mediated ERAD pathway and enhance the subunit folding by promoting subunit interactions with major GABAA receptors-interacting chaperones, BiP and calnexin. In summary, we report that DNP and DHEC remodel the endoplasmic reticulum proteostasis network to restore the functional surface expression of mutant GABAA receptors.
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Affiliation(s)
- Xiao-Jing Di
- Department of Physiology and Biophysics, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA
| | - Ya-Juan Wang
- Department of Physiology and Biophysics, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA; Center for Proteomics and Bioinformatics and Department of Epidemiology and Biostatistics, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA
| | - Edmund Cotter
- Queensland Brain Institute, the University of Queensland, Brisbane, QLD 4072, Australia
| | - Meng Wang
- Department of Physiology and Biophysics, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA
| | - Angela L Whittsette
- Department of Physiology and Biophysics, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA
| | - Dong-Yun Han
- Department of Physiology and Biophysics, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA
| | - Panjamaporn Sangwung
- Department of Physiology and Biophysics, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA
| | - Renae Brown
- Department of Physiology and Biophysics, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA
| | - Joseph W Lynch
- Queensland Brain Institute, the University of Queensland, Brisbane, QLD 4072, Australia
| | - Angelo Keramidas
- Queensland Brain Institute, the University of Queensland, Brisbane, QLD 4072, Australia.
| | - Ting-Wei Mu
- Department of Physiology and Biophysics, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA.
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27
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Arias HR, Do Rego JL, Do Rego JC, Chen Z, Anouar Y, Scholze P, Gonzales EB, Huang R, Chagraoui A. Coronaridine congeners potentiate GABA A receptors and induce sedative activity in mice in a benzodiazepine-insensitive manner. Prog Neuropsychopharmacol Biol Psychiatry 2020; 101:109930. [PMID: 32194202 DOI: 10.1016/j.pnpbp.2020.109930] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/30/2019] [Revised: 03/13/2020] [Accepted: 03/15/2020] [Indexed: 12/23/2022]
Abstract
To determine whether (+)-catharanthine induces sedative- or anxiolytic/anxiogenic-like activity in male mice, proper animal paradigms were used. The results showed that (+)-catharanthine induces sedative-like activity in the 63-72 mg/Kg dose range in a flumazenil-insensitive manner, but neither this effect nor anxiolytic/anxiogenic-like activity was observed at lower doses. To determine the underlying molecular mechanism of the sedative-like activity, electrophysiological and radioligand binding experiments were performed with (+)-catharanthine and (±)-18-methoxycoronaridine [(±)-18-MC] on GABAA (GABAARs) and glycine receptors (GlyRs). Coronaridine congeners both activated and potentiated a variety of human (h) GABAARs, except hρ1. (+)-Catharanthine-induced potentiation followed this receptor selectivity (EC50's in μM): hα1β2 (4.6 ± 0.8) > hα2β2γ2 (12.6 ± 3.8) ~ hα1β2γ2 (14.4 ± 4.6) indicating that both α1 and α2 are equally important, whereas γ2 is not necessary. (+)-Catharanthine was >2-fold more potent and efficient than (±)-18-MC at hα1β2γ2. (+)-Catharanthine also potentiated, whereas (±)-18-MC inhibited, hα1 GlyRs with very low potency. Additional [3H]-flunitrazepam competition binding experiments using rat cerebellum membranes clearly demonstrated that these ligands do not bind to the benzodiazepine site. This is supported by the observed activity at hα1β2 (lacking the BDZ site) and similar effects between α1- and α2-containing GABAARs. Our study shows, for the first time, that (+)-catharanthine induced sedative-like effects in mice, and coronaridine congeners potentiated human α1β2γ2, α1β2, and hα2β2γ2, but not ρ1, GABAARs, both in a benzodiazepine-insensitive fashion, whereas only (+)-catharanthine slightly potentiated GlyRs.
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Affiliation(s)
- Hugo R Arias
- Department of Pharmacology and Physiology, Oklahoma State University College of Osteopathic Medicine, Tahlequah, OK, USA.
| | - Jean Luc Do Rego
- Behavioral Analysis Platform SCAC, Institute for Research and Innovation in Biomedicine (IRIB), University of Rouen Normandy, Rouen, France
| | - Jean Claude Do Rego
- Behavioral Analysis Platform SCAC, Institute for Research and Innovation in Biomedicine (IRIB), University of Rouen Normandy, Rouen, France
| | - Zhenglan Chen
- Department of Pharmacology and Neuroscience, Institute for Health Aging, University of North Texas Health Science Center at Fort Worth, TX, USA
| | - Youssef Anouar
- Laboratory of Neuronal and Neuroendocrine Differentiation and Communication, Normandie University, UNIROUEN, INSERM U1239, Institute for Research and Innovation in Biomedicine of Normandy (IRIB) Rouen, France
| | - Petra Scholze
- Department of Pathobiology of the Nervous System, Center for Brain Research, Medical University of Vienna, Vienna, Austria
| | - Eric B Gonzales
- Department of Pharmacology and Neuroscience, Institute for Health Aging, University of North Texas Health Science Center at Fort Worth, TX, USA
| | - Renqi Huang
- Department of Pharmacology and Neuroscience, Institute for Health Aging, University of North Texas Health Science Center at Fort Worth, TX, USA
| | - Abdeslam Chagraoui
- Laboratory of Neuronal and Neuroendocrine Differentiation and Communication, Normandie University, UNIROUEN, INSERM U1239, Institute for Research and Innovation in Biomedicine of Normandy (IRIB) Rouen, France; Department of Medical Biochemistry, Rouen University Hospital, CHU de Rouen, France.
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28
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Devaud LL, Alavi M, Jensen JP, Helms ML, Nipper MA, Finn DA. Sexually divergent changes in select brain proteins and neurosteroid levels after a history of ethanol drinking and intermittent PTSD-like stress exposure in adult C57BL/6J mice. Alcohol 2020; 83:115-125. [PMID: 30529168 DOI: 10.1016/j.alcohol.2018.12.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2018] [Revised: 11/30/2018] [Accepted: 12/03/2018] [Indexed: 11/25/2022]
Abstract
Human studies reported that the number of past-year stressors was positively related to current drinking patterns, including binge drinking. In animal models, exposure to predator odor stress (PS), considered a model of traumatic stress, consistently increased ethanol intake. Recently, we reported that repeated PS significantly increased ethanol intake and had a synergistic interaction with prior binge drinking (binge group) in male but not in female C57BL/6J mice, when compared to mice without prior binge exposure (control group). The current studies utilized plasma and dissected prefrontal cortex (PFC) and hippocampal tissue from these animals and from age-matched naïve mice (naïve group). Western blots assessed relative protein levels of P450scc (an enzyme involved in the first step of steroidogenesis), of GABAA receptor α2 and α4 subunits, and of two proteins involved in synaptic plasticity - ARC (activity-regulated cytoskeletal protein) and synaptophysin. Gas chromatography-mass spectrometry simultaneously quantified 10 neurosteroid levels in plasma. A history of ethanol drinking and PS exposure produced brain regional and sex differences in the changes in proteins examined as well as in the pattern of neurosteroid levels versus (vs.) values in naïve mice. For instance, P450scc levels were significantly increased only in binge and control female PFC and hippocampus vs. naïve mice. Some neurosteroid levels were significantly altered by binge treatment in both males and females, whereas others were only significantly altered in males. These sexually divergent changes in neurosteroid and protein levels add to evidence for sex differences in the neurochemical systems influenced by traumatic stress and a history of ethanol drinking.
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29
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Hamamoto O, Tirapelli DPDC, Lizarte Neto FS, Freitas-Lima P, Saggioro FP, Cirino MLDA, Assirati JA, Serafini LN, Velasco TR, Sakamoto AC, Carlotti CG. Modulation of NMDA receptor by miR-219 in the amygdala and hippocampus of patients with mesial temporal lobe epilepsy. J Clin Neurosci 2020; 74:180-186. [PMID: 32111564 DOI: 10.1016/j.jocn.2020.02.024] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2019] [Accepted: 02/10/2020] [Indexed: 01/28/2023]
Abstract
Mesial temporal lobe epilepsy with hippocampal sclerosis is the most frequent form of focal epilepsy in adults, and it is often refractory to drug treatment. Regardless of the efforts on developing new antiepileptic drugs for refractory cases, studies suggest a need for better understanding the molecular bases of epilepsy. The microRNAs have been progressively investigated as potential targets for both epilepsy mechanisms elucidation and treatment. Therefore, the goal of this study was to evaluate the differential expression of miR-219, miR-181b, and miR-195, previously described as regulators of the excitatory neurotransmitter receptors NMDA-R1 and AMPA-GluR2 and inhibitory neurotransmitter GABAA (α2, β3, and γ2 subunits) in the amygdala and hippocampus of patients with mesial temporal lobe epilepsy. Based on genes and miRNAs' quantitative Polymerase Chain Reaction (qPCR) from 18 patients with epilepsy, our results showed an inverse relationship between miR-219 and NMDA-NR1 expression in both the amygdala and hippocampus in comparison to their expression in controls. NR1 and GluR2 were upregulated in the amygdala of epileptic patients. Low miR-195 expression was observed in the amygdala of patients with epilepsy. Our findings indicate that miR-219 has a possible regulatory role in excitatory neurotransmission in patients with epilepsy, contributing to the new avenue of miRNA biology in drug-resistant epilepsy, reserving huge potential for future applications and clinical interventions in conjunction with existing therapies.
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Affiliation(s)
- Osmi Hamamoto
- Department of Surgery and Anatomy, Ribeirao Preto Medical School, University of Sao Paulo, Ribeirao Preto, SP, Brazil
| | | | - Fermino Sanches Lizarte Neto
- Department of Surgery and Anatomy, Ribeirao Preto Medical School, University of Sao Paulo, Ribeirao Preto, SP, Brazil
| | - Priscila Freitas-Lima
- Department of Surgery and Anatomy, Ribeirao Preto Medical School, University of Sao Paulo, Ribeirao Preto, SP, Brazil; Barao de Maua University Center, Ribeirao Preto, SP, Brazil
| | - Fabiano Pinto Saggioro
- Department of Pathology, Ribeirao Preto Medical School, University of Sao Paulo, Ribeirao Preto, SP, Brazil
| | - Mucio Luiz de Assis Cirino
- Department of Surgery and Anatomy, Ribeirao Preto Medical School, University of Sao Paulo, Ribeirao Preto, SP, Brazil
| | - João Alberto Assirati
- Department of Surgery and Anatomy, Ribeirao Preto Medical School, University of Sao Paulo, Ribeirao Preto, SP, Brazil
| | - Luciano Neder Serafini
- Department of Pathology, Ribeirao Preto Medical School, University of Sao Paulo, Ribeirao Preto, SP, Brazil
| | - Tonicarlo Rodrigues Velasco
- Department of Neurosciences and Behavioral Sciences, Ribeirao Preto Medical School, University of Sao Paulo, Ribeirao Preto, SP, Brazil
| | - Américo Ceiki Sakamoto
- Department of Neurosciences and Behavioral Sciences, Ribeirao Preto Medical School, University of Sao Paulo, Ribeirao Preto, SP, Brazil
| | - Carlos Gilberto Carlotti
- Department of Surgery and Anatomy, Ribeirao Preto Medical School, University of Sao Paulo, Ribeirao Preto, SP, Brazil
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Akbar S, Subhan F, Shahid M, Wadood A, Shahbaz N, Farooq U, Ayaz M, Raziq N. 6-Methoxyflavanone abates cisplatin-induced neuropathic pain apropos anti-inflammatory mechanisms: A behavioral and molecular simulation study. Eur J Pharmacol 2020; 872:172972. [PMID: 32006559 DOI: 10.1016/j.ejphar.2020.172972] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2019] [Revised: 12/31/2019] [Accepted: 01/28/2020] [Indexed: 01/03/2023]
Abstract
Cisplatin is used as a first line therapy in treating cancers. However, its use is often accompanied with the development of peripheral neuropathy. 6-Methoxyflavanone (6-MeOF) is a positive allosteric modulator at GABAA receptors and is known for attenuating diabetes-induced neuropathic pain. Neuropathy was induced in male Sprague-Dawley rats (150-250 g), via intraperitoneal injection of cisplatin (3 mg/kg) once a week for four consecutive weeks. 6-MeOF (25, 50 and 75 mg/kg, i.p) and gabapentin (75 mg/kg, i.p) were administered 30 min before each cisplatin injection. Static and dynamic allodynia were assessed using von Frey filaments and cotton buds. The anti-inflammatory activity was analyzed with plethysmometer. Body weights were also measured each week. The binding affinity of 6-MeOF with chloride channel, Cyclooxygenase-1 (COX-1) and Cyclooxygenase-2 (COX-2) was studied using docking approach. The in vitro COX-1 and COX-2 inhibitory effect of 6-MeOF was conducted with COX colorimetric assay. Administration of cisplatin for four consecutive weeks induced static (decreased paw withdrawal threshold; PWT) and dynamic allodynia (decreased paw withdrawal latency; PWL). Co-administration of 6-MeOF for four weeks significantly attenuated the cisplatin-induced expression of nocifensive behaviors observed as significant increase in PWT and PWL. Moreover, it also prevented the body weight loss induced by cisplatin administration. In silico studies depicted a good interaction of 6-MeOF with chloride ion channels and COX-1 and COX-2 enzymes. The in vitro study confirmed the inhibitory activity of 6-MeOF for COX-1 and COX-2. 6-MeOF may be effective in attenuating cisplatin-induced allodynia, probably through interaction with GABAergic receptors and reducing inflammation.
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Affiliation(s)
- Shehla Akbar
- Department of Pharmacy, CECOS University of IT and Emerging Science, Peshawar, Pakistan.
| | - Fazal Subhan
- Department of Pharmacy, CECOS University of IT and Emerging Science, Peshawar, Pakistan.
| | - Muhammad Shahid
- Department of Pharmacy, Sarhad University of Science and IT, Peshawar, Pakistan.
| | - Abdul Wadood
- Department of Biochemistry, UCS, Shankar Abdul Wali Khan University, Mardan, Pakistan.
| | - Naila Shahbaz
- Department of Pharmacy, Sarhad University of Science and IT, Peshawar, Pakistan.
| | - Umar Farooq
- Department of Pharmacy, Sarhad University of Science and IT, Peshawar, Pakistan.
| | - Muhammad Ayaz
- Department of Pharmacy, University of Malakand, Peshawar, Pakistan.
| | - Naila Raziq
- Department of Pharmacy, Sarhad University of Science and IT, Peshawar, Pakistan.
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31
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Benkherouf AY, Logrén N, Somborac T, Kortesniemi M, Soini SL, Yang B, Salo-Ahen OMH, Laaksonen O, Uusi-Oukari M. Hops compounds modulatory effects and 6-prenylnaringenin dual mode of action on GABA A receptors. Eur J Pharmacol 2020; 873:172962. [PMID: 32001220 DOI: 10.1016/j.ejphar.2020.172962] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2019] [Revised: 12/17/2019] [Accepted: 01/24/2020] [Indexed: 02/05/2023]
Abstract
Hops (Humulus lupulus L.), a major component of beer, contain potentially neuroactive compounds that made it useful in traditional medicine as a sleeping aid. The present study aims to investigate the individual components in hops acting as allosteric modulators in GABAA receptors and bring further insight into the mode of action behind the sedative properties of hops. GABA-potentiating effects were measured using [3H]ethynylbicycloorthobenzoate (EBOB) radioligand binding assay in native GABAA receptors. Flumazenil sensitivity of GABA-potentiating effects, [3H]Ro 15-4513, and [3H]flunitrazepam binding assays were used to examine the binding to the classical benzodiazepines site. Humulone (alpha acid) and 6-prenylnaringenin (prenylflavonoid) were the most potent compounds displaying a modulatory activity at low micromolar concentrations. Humulone and 6-prenylnaringenin potentiated GABA-induced displacement of [3H]EBOB binding in a concentration-dependent manner where the IC50 values for this potentiation in native GABAA receptors were 3.2 μM and 3.7 μM, respectively. Flumazenil had no significant effects on humulone- or 6-prenylnaringenin-induced displacement of [3H]EBOB binding. [3H]Ro 15-4513 and [3H]flunitrazepam displacements were only minor with humulone but surprisingly prominent with 6-prenylnaringenin despite its flumazenil-insensitive modulatory activity. Thus, we applied molecular docking methods to investigate putative binding sites and poses of 6-prenylnaringenin at the GABAA receptor α1β2γ2 isoform. Radioligand binding and docking results suggest a dual mode of action by 6-prenylnaringenin on GABAA receptors where it may act as a positive allosteric modulator at α+β- binding interface as well as a null modulator at the flumazenil-sensitive α+γ2- binding interface.
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Affiliation(s)
- Ali Y Benkherouf
- Integrative Physiology and Pharmacology, Institute of Biomedicine, University of Turku, Finland
| | - Nora Logrén
- Food Chemistry and Food Development, Department of Biochemistry, University of Turku, Finland
| | - Tamara Somborac
- Pharmaceutical Sciences Laboratory and Structural Bioinformatics Laboratory, Faculty of Science and Engineering, Åbo Akademi University, Turku, Finland
| | - Maaria Kortesniemi
- Food Chemistry and Food Development, Department of Biochemistry, University of Turku, Finland
| | - Sanna L Soini
- Integrative Physiology and Pharmacology, Institute of Biomedicine, University of Turku, Finland
| | - Baoru Yang
- Food Chemistry and Food Development, Department of Biochemistry, University of Turku, Finland
| | - Outi M H Salo-Ahen
- Pharmaceutical Sciences Laboratory and Structural Bioinformatics Laboratory, Faculty of Science and Engineering, Åbo Akademi University, Turku, Finland
| | - Oskar Laaksonen
- Food Chemistry and Food Development, Department of Biochemistry, University of Turku, Finland
| | - Mikko Uusi-Oukari
- Integrative Physiology and Pharmacology, Institute of Biomedicine, University of Turku, Finland.
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Halbhuber L, Achtner C, Luhmann HJ, Sinning A, Kilb W. Coincident Activation of Glutamate Receptors Enhances GABA A Receptor-Induced Ionic Plasticity of the Intracellular Cl --Concentration in Dissociated Neuronal Cultures. Front Cell Neurosci 2019; 13:497. [PMID: 31787883 PMCID: PMC6856009 DOI: 10.3389/fncel.2019.00497] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2019] [Accepted: 10/21/2019] [Indexed: 01/09/2023] Open
Abstract
Massive activation of γ-amino butyric acid A (GABAA) receptors during pathophysiological activity induces an increase in the intracellular Cl--concentration ([Cl-]i), which is sufficient to render GABAergic responses excitatory. However, to what extent physiological levels of GABAergic activity can influence [Cl-]i is not known. Aim of the present study is to reveal whether moderate activation of GABAA receptors mediates functionally relevant [Cl-]i changes and whether these changes can be augmented by coincident glutamatergic activity. To address these questions, we used whole-cell patch-clamp recordings from cultured cortical neurons [at days in vitro (DIV) 6-22] to determine changes in the GABA reversal potential (EGABA) induced by short bursts of GABAergic and/or synchronized glutamatergic stimulation. These experiments revealed that pressure-application of 10 short muscimol pulses at 10 Hz induced voltage-dependent [Cl-]i changes. Under current-clamp conditions this muscimol burst induced a [Cl-]i increase of 3.1 ± 0.4 mM (n = 27), which was significantly enhanced to 4.6 ± 0.5 mM (n = 27) when glutamate was applied synchronously with the muscimol pulses. The muscimol-induced [Cl-]i increase significantly attenuated the inhibitory effect of GABA, as determined by the GABAergic rheobase shift. The synchronous coapplication of glutamate pulses had no additional effect on the attenuation of GABAergic inhibition, despite the larger [Cl-]i transients under these conditions. In summary, these results indicate that moderate GABAergic activity can induce functionally relevant [Cl-]i transients, which were enhanced by coincident glutamate pulses. This ionic plasticity of [Cl-]i may contribute to short-term plasticity of the GABAergic system.
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Affiliation(s)
- Lisa Halbhuber
- Institute of Physiology, University Medical Center Mainz, Johannes Gutenberg University, Mainz, Germany
| | - Cécilia Achtner
- Institute of Physiology, University Medical Center Mainz, Johannes Gutenberg University, Mainz, Germany
| | - Heiko J Luhmann
- Institute of Physiology, University Medical Center Mainz, Johannes Gutenberg University, Mainz, Germany
| | - Anne Sinning
- Institute of Physiology, University Medical Center Mainz, Johannes Gutenberg University, Mainz, Germany
| | - Werner Kilb
- Institute of Physiology, University Medical Center Mainz, Johannes Gutenberg University, Mainz, Germany
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Tikhonova TA, Rassokhina IV, Kondrakhin EA, Fedosov MA, Bukanova JV, Rossokhin AV, Sharonova IN, Kovalev GI, Zavarzin IV, Volkova YA. Development of 1,3-thiazole analogues of imidazopyridines as potent positive allosteric modulators of GABA A receptors. Bioorg Chem 2019; 94:103334. [PMID: 31711764 DOI: 10.1016/j.bioorg.2019.103334] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2019] [Revised: 09/17/2019] [Accepted: 09/30/2019] [Indexed: 12/14/2022]
Abstract
Structure-activity relationship studies were conducted in the search for 1,3-thiazole isosteric analogs of imidazopyridine drugs (Zolpidem, Alpidem). Three series of novel γ-aminobutyric acid receptor (GABAAR) ligands belonging to imidazo[2,1-b]thiazoles, imidazo[2,1-b][1,3,4]thiadiazoles, and benzo[d]imidazo[2,1-b]thiazoles were synthesized and characterized as active agents against GABAAR benzodiazepine-binding site. In each of these series, potent compounds were discovered using a radioligand competition binding assay. The functional properties of highest-affinity compounds 28 and 37 as GABAAR positive allosteric modulators (PAMs) were determined by electrophysiological measurements. In vivo studies on zebrafish demonstrated their potential for the further development of anxiolytics. Using the OECD "Fish, Acute Toxicity Test" active compounds were found safe and non-toxic. Structural bases for activity of benzo[d]imidazo[2,1-b]thiazoles were proposed using molecular docking studies. The isosteric replacement of the pyridine nuclei by 1,3-thiazole, 1,3,4-thiadiazole, or 1,3-benzothiazole in the ring-fused imidazole class of GABAAR PAMs was shown to be promising for the development of novel hypnotics, anxiolytics, anticonvulsants, and sedatives drug-candidates.
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Affiliation(s)
- Tatyana A Tikhonova
- N. D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, 47 Leninsky prosp., 119991 Moscow, Russia
| | - Irina V Rassokhina
- N. D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, 47 Leninsky prosp., 119991 Moscow, Russia
| | - Eugeny A Kondrakhin
- V. V. Zakusov Institute of Pharmacology, Russian Academy of Sciences, 8 Baltiyskaya Str., 125315 Moscow, Russia
| | - Mikhail A Fedosov
- N. D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, 47 Leninsky prosp., 119991 Moscow, Russia
| | - Julia V Bukanova
- Research Center of Neurology, 5 By-str. Obukha, 105064 Moscow, Russia
| | | | - Irina N Sharonova
- Research Center of Neurology, 5 By-str. Obukha, 105064 Moscow, Russia
| | - Georgy I Kovalev
- V. V. Zakusov Institute of Pharmacology, Russian Academy of Sciences, 8 Baltiyskaya Str., 125315 Moscow, Russia
| | - Igor V Zavarzin
- N. D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, 47 Leninsky prosp., 119991 Moscow, Russia
| | - Yulia A Volkova
- N. D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, 47 Leninsky prosp., 119991 Moscow, Russia.
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Kasugai Y, Vogel E, Hörtnagl H, Schönherr S, Paradiso E, Hauschild M, Göbel G, Milenkovic I, Peterschmitt Y, Tasan R, Sperk G, Shigemoto R, Sieghart W, Singewald N, Lüthi A, Ferraguti F. Structural and Functional Remodeling of Amygdala GABAergic Synapses in Associative Fear Learning. Neuron 2019; 104:781-794.e4. [PMID: 31543297 DOI: 10.1016/j.neuron.2019.08.013] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2019] [Revised: 07/09/2019] [Accepted: 08/07/2019] [Indexed: 01/12/2023]
Abstract
Associative learning is thought to involve different forms of activity-dependent synaptic plasticity. Although previous studies have mostly focused on learning-related changes occurring at excitatory glutamatergic synapses, we found that associative learning, such as fear conditioning, also entails long-lasting functional and structural plasticity of GABAergic synapses onto pyramidal neurons of the murine basal amygdala. Fear conditioning-mediated structural remodeling of GABAergic synapses was associated with a change in mIPSC kinetics and an increase in the fraction of synaptic benzodiazepine-sensitive (BZD) GABAA receptors containing the α2 subunit without altering the intrasynaptic distribution and overall amount of BZD-GABAA receptors. These structural and functional synaptic changes were partly reversed by extinction training. These findings provide evidence that associative learning, such as Pavlovian fear conditioning and extinction, sculpts inhibitory synapses to regulate inhibition of active neuronal networks, a process that may tune amygdala circuit responses to threats.
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Affiliation(s)
- Yu Kasugai
- Department of Pharmacology, Medical University of Innsbruck, Innsbruck 6020, Austria
| | - Elisabeth Vogel
- Friedrich Miescher Institute for Biomedical Research, Basel 4058, Switzerland
| | - Heide Hörtnagl
- Department of Pharmacology, Medical University of Innsbruck, Innsbruck 6020, Austria
| | - Sabine Schönherr
- Department of Pharmacology, Medical University of Innsbruck, Innsbruck 6020, Austria
| | - Enrica Paradiso
- Department of Pharmacology, Medical University of Innsbruck, Innsbruck 6020, Austria
| | - Markus Hauschild
- Department of Pharmacology and Toxicology, Institute of Pharmacy and CMBI, University of Innsbruck, Innsbruck 6020, Austria
| | - Georg Göbel
- Department of Medical Statistics, Informatics and Health Economics, Medical University of Innsbruck, Innsbruck 6020, Austria
| | - Ivan Milenkovic
- Center for Brain Research, Department of Molecular Neurosciences, Medical University of Vienna, Vienna 1090, Austria
| | - Yvan Peterschmitt
- Department of Pharmacology, Medical University of Innsbruck, Innsbruck 6020, Austria; Center for Brain Research, Department of Molecular Neurosciences, Medical University of Vienna, Vienna 1090, Austria
| | - Ramon Tasan
- Department of Pharmacology, Medical University of Innsbruck, Innsbruck 6020, Austria
| | - Günther Sperk
- Department of Pharmacology, Medical University of Innsbruck, Innsbruck 6020, Austria
| | - Ryuichi Shigemoto
- Institute of Science and Technology Austria, Klosterneuburg 3400, Austria
| | - Werner Sieghart
- Center for Brain Research, Department of Molecular Neurosciences, Medical University of Vienna, Vienna 1090, Austria
| | - Nicolas Singewald
- Department of Pharmacology and Toxicology, Institute of Pharmacy and CMBI, University of Innsbruck, Innsbruck 6020, Austria
| | - Andreas Lüthi
- Friedrich Miescher Institute for Biomedical Research, Basel 4058, Switzerland; University of Basel, Basel, Switzerland
| | - Francesco Ferraguti
- Department of Pharmacology, Medical University of Innsbruck, Innsbruck 6020, Austria.
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35
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Iorio MT, Rehman S, Bampali K, Stoeger B, Schnürch M, Ernst M, Mihovilovic MD. Variations on a scaffold - Novel GABA A receptor modulators. Eur J Med Chem 2019; 180:340-349. [PMID: 31325782 DOI: 10.1016/j.ejmech.2019.07.008] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2019] [Revised: 07/02/2019] [Accepted: 07/02/2019] [Indexed: 11/24/2022]
Abstract
Allosteric ligands of GABAA receptors exist in many different chemotypes owing to their great usefulness as therapeutics, with benzodiazepines being among the best known examples. Many allosteric binding sites have been described, among them a site at the extracellular interface between the alpha principal face and the beta complementary face (α+/β-). Pyrazoloquinolinones have been shown to bind at α+/β-binding sites of GABAA receptors, exerting chiefly positive allosteric modulation at this location. In order to further explore molecular determinants of this type of allosteric modulation, we synthesized a library of ligands based on the PQ pharmacophore employing a ring-chain bioisosteric approach. In this study we analyzed the structure-activity-relationship (SAR) of these novel ligands based on an azo-biaryl structural motif in α1β3 GABAA receptors, indicating interesting novel properties of the compound class.
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Affiliation(s)
- Maria Teresa Iorio
- TU Wien, Institute of Applied Synthetic Chemistry, Getreidemarkt 9/163-OC, 1060, Vienna, Austria.
| | - Sabah Rehman
- Medical University of Vienna, Center for Brain Research, Spitalgasse 4, 1090, Vienna, Austria.
| | - Konstantina Bampali
- Medical University of Vienna, Center for Brain Research, Spitalgasse 4, 1090, Vienna, Austria.
| | - Berthold Stoeger
- TU Wien, Institute of Applied Synthetic Chemistry, Getreidemarkt 9/163-OC, 1060, Vienna, Austria.
| | - Michael Schnürch
- TU Wien, Institute of Applied Synthetic Chemistry, Getreidemarkt 9/163-OC, 1060, Vienna, Austria.
| | - Margot Ernst
- Medical University of Vienna, Center for Brain Research, Spitalgasse 4, 1090, Vienna, Austria.
| | - Marko D Mihovilovic
- TU Wien, Institute of Applied Synthetic Chemistry, Getreidemarkt 9/163-OC, 1060, Vienna, Austria.
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36
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Hernandez CC, Macdonald RL. A structural look at GABA A receptor mutations linked to epilepsy syndromes. Brain Res 2019; 1714:234-247. [PMID: 30851244 DOI: 10.1016/j.brainres.2019.03.004] [Citation(s) in RCA: 58] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2018] [Revised: 02/25/2019] [Accepted: 03/06/2019] [Indexed: 12/12/2022]
Abstract
Understanding the genetic variation in GABAA receptor subunit genes (GABRs), GABRA1-6, GABRB1-3, GABRG1-3 and GABRD, in individuals affected by epilepsy may improve the diagnosis and treatment of epilepsy syndromes through identification of disease-associated variants. However, the lack of functional analysis and validation of many novel and previously reported familial and de novo mutations have made it challenging to address meaningful gene associations with epilepsy syndromes. GABAA receptors belong to the Cys-loop receptor family. Even though GABAA receptor mutant residues are widespread among different GABRs, their frequent occurrence in important structural domains that share common functional features suggests associations between structure and function.
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Affiliation(s)
- Ciria C Hernandez
- Life Sciences Institute, University of Michigan, Ann Arbor, MI, USA.
| | - Robert L Macdonald
- Department of Neurology, Vanderbilt University Medical Center, Nashville, TN, USA
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37
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Benkherouf AY, Soini SL, Stompor M, Uusi-Oukari M. Positive allosteric modulation of native and recombinant GABA A receptors by hops prenylflavonoids. Eur J Pharmacol 2019; 852:34-41. [PMID: 30797788 DOI: 10.1016/j.ejphar.2019.02.034] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2018] [Revised: 02/19/2019] [Accepted: 02/20/2019] [Indexed: 10/27/2022]
Abstract
Hops are a major component of beer that is added during brewing. In addition to its wide range of bioactivity, it exhibits neuroactive properties as a sedative and sleeping aid. The compounds responsible for this activity are yet to be revealed and understood in terms of their pharmacological properties. Here we evaluated the potential of several hops flavonoids in modulating the GABAergic activity and assessed their selectivity to GABAA receptors subtypes. GABA-potentiating effects were measured using [3H]ethynylbicycloorthobenzoate (EBOB) radioligand binding assay in native and recombinant α1β3γ2, α2β3γ2 and α6β3δ receptors expressed in HEK293 cells. Flumazenil sensitivity of GABA-potentiating effects and [3H]Ro 15-4513 binding assay were used to examine the flavonoids binding to benzodiazepine site. The prenylflavonoids xanthohumol (XN), isoxanthohumol (IXN) and 8-prenylnaringenin (8PN) potentiated GABA-induced displacement of [3H]EBOB binding in a concentration-dependent manner. The IC50 for this potentiation in native GABAA receptors were 29.7 µM, 11.6 µM, 7.3 µM, respectively. In recombinant receptors, the sensitivity to prenylflavonoid potentiation of GABA-induced displacement of [3H]EBOB binding followed the order α6β3δ > α2β3γ2 > α1β3γ2 with the strongest inhibition observed by 8PN in α6β3δ (IC50 = 3.6 μM). Flumazenil had no significant effect on the prenylflavonoid-induced displacement of [3H]EBOB binding and [3H]Ro 15-4513 displacement from native GABAA receptors was only detected at high micromolar concentrations (100 µM). We identified potent prenylflavonoids in hops that positively modulate GABA-induced responses in native and αβγ/δ recombinant GABAA receptors at low micromolar concentrations. These GABAergic modulatory effects were not mediated via the high-affinity benzodiazepine binding site.
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Affiliation(s)
- Ali Y Benkherouf
- Centre of Integrative Physiology and Pharmacology, Institute of Biomedicine, University of Turku, Finland
| | - Sanna L Soini
- Centre of Integrative Physiology and Pharmacology, Institute of Biomedicine, University of Turku, Finland
| | - Monika Stompor
- Centre for Innovative Research in Medical and Natural Sciences, Faculty of Medicine, University of Rzeszów, Poland
| | - Mikko Uusi-Oukari
- Centre of Integrative Physiology and Pharmacology, Institute of Biomedicine, University of Turku, Finland.
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38
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Abstract
The female reproductive hormones progesterone and estrogen regulate network excitability. Fluctuations in the circulating levels of these hormones during the menstrual cycle cause frequent seizures during certain phases of the cycle in women with epilepsy. This seizure exacerbation, called catamenial epilepsy, is a dominant form of drug-refractory epilepsy in women of reproductive age. Progesterone, through its neurosteroid derivative allopregnanolone, increases γ-aminobutyric acid type-A receptor (GABAR)-mediated inhibition in the brain and keeps seizures under control. Catamenial seizures are believed to be a neurosteroid withdrawal symptom, and it was hypothesized that exogenous administration of progesterone to maintain its levels high during luteal phase will treat catamenial seizures. However, in a multicenter, double-blind, phase III clinical trial, progesterone treatment did not suppress catamenial seizures. The expression of GABARs with reduced neurosteroid sensitivity in epileptic animals may explain the failure of the progesterone clinical trial. The expression of neurosteroid-sensitive δ subunit-containing GABARs is reduced, and the expression of α4γ2 subunit-containing GABARs is upregulated, which alters the inhibition of dentate granule cells in epilepsy. These changes reduce the endogenous neurosteroid control of seizures and contribute to catamenial seizures.
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Affiliation(s)
- Suchitra Joshi
- Department of Neurology, University of Virginia, Charlottesville, VA 22908, United States.
| | - Jaideep Kapur
- Department of Neurology, University of Virginia, Charlottesville, VA 22908, United States; Department of Neuroscience, University of Virginia, Charlottesville, VA 22908, United States
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39
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Nipper MA, Jensen JP, Helms ML, Ford MM, Crabbe JC, Rossi DJ, Finn DA. Genotype Differences in Sensitivity to the Anticonvulsant Effect of the Synthetic Neurosteroid Ganaxolone during Chronic Ethanol Withdrawal. Neuroscience 2018; 397:127-137. [PMID: 30513375 DOI: 10.1016/j.neuroscience.2018.11.045] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2018] [Revised: 11/26/2018] [Accepted: 11/28/2018] [Indexed: 01/05/2023]
Abstract
Sensitivity to anticonvulsant effects of the γ-aminobutyric acidA receptor-active neurosteroid allopregnanolone (ALLO) during ethanol withdrawal varies across genotypes, with high sensitivity in genotypes with mild withdrawal and low sensitivity in genotypes with high withdrawal. The present studies determined whether the resistance to ALLO during withdrawal in mouse genotypes with high handling-induced convulsions (HICs) during withdrawal could be overcome with use of ganaxolone (GAN), the metabolically stable derivative of ALLO. In separate studies, male and female Withdrawal Seizure-Prone (WSP-1) and DBA/2J (D2) mice were exposed to air (controls) or 72-h ethanol vapor and then were scored for HICs during withdrawal (hourly for the first 12 h, then at hours 24 and 25). After the HIC scoring at hours 5 and 9, mice were injected with 10 mg/kg GAN or vehicle. Area under the HIC curve (AUC) for hours 5-12 was analyzed. In control WSP-1 mice, GAN significantly reduced AUC by 52% (males) and 63% (females), with effects that were absent or substantially reduced during withdrawal. In contrast, GAN significantly reduced AUC in both control and ethanol-withdrawing male and female D2 mice. AUC was decreased by 81% (males) and 70% (females) in controls and by 35% (males) and 21% (females) during withdrawal. The significant anticonvulsant effect of GAN during withdrawal in D2 but not WSP-1 mice suggests that different mechanisms may contribute to ALLO insensitivity during withdrawal in these two genotypes. Importantly, the results in D2 mice suggest that GAN may be a useful treatment for ethanol withdrawal-induced seizures.
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Affiliation(s)
- Michelle A Nipper
- Department of Behavioral Neuroscience, Oregon Health & Science University, Portland, OR 97239, United States.
| | - Jeremiah P Jensen
- Department of Behavioral Neuroscience, Oregon Health & Science University, Portland, OR 97239, United States
| | - Melinda L Helms
- Department of Behavioral Neuroscience, Oregon Health & Science University, Portland, OR 97239, United States
| | - Matthew M Ford
- Department of Behavioral Neuroscience, Oregon Health & Science University, Portland, OR 97239, United States; Division of Neuroscience, Oregon National Primate Research Center, Oregon Health & Science University, Beaverton, OR 97006, United States
| | - John C Crabbe
- Department of Behavioral Neuroscience, Oregon Health & Science University, Portland, OR 97239, United States; Portland Alcohol Research Center, VA Portland Health Care System, Portland, OR 97239, United States
| | - David J Rossi
- Department of Behavioral Neuroscience, Oregon Health & Science University, Portland, OR 97239, United States; Department of Integrative Physiology and Neuroscience, Washington State University, Pullman, WA 99164, United States
| | - Deborah A Finn
- Department of Behavioral Neuroscience, Oregon Health & Science University, Portland, OR 97239, United States; Portland Alcohol Research Center, VA Portland Health Care System, Portland, OR 97239, United States
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Lombardi A, Jedlicka P, Luhmann HJ, Kilb W. Giant Depolarizing Potentials Trigger Transient Changes in the Intracellular Cl - Concentration in CA3 Pyramidal Neurons of the Immature Mouse Hippocampus. Front Cell Neurosci 2018; 12:420. [PMID: 30515078 PMCID: PMC6255825 DOI: 10.3389/fncel.2018.00420] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2018] [Accepted: 10/26/2018] [Indexed: 11/30/2022] Open
Abstract
Giant depolarizing potentials (GDPs) represent a typical spontaneous activity pattern in the immature hippocampus. GDPs are mediated by GABAergic and glutamatergic synaptic inputs and their initiation requires an excitatory GABAergic action, which is typical for immature neurons due to their elevated intracellular Cl- concentration ([Cl-]i). Because GABAA receptors are ligand-gated Cl- channels, activation of these receptors can potentially influence [Cl-]i. However, whether the GABAergic activity during GDPs influences [Cl-]i is unclear. To address this question we performed whole-cell and gramicidin-perforated patch-clamp recordings from visually identified CA3 pyramidal neurons in immature hippocampal slices of mice at postnatal days 4–7. These experiments revealed that the [Cl-]i of CA3 neurons displays a considerable heterogeneity, ranging from 13 to 70 mM (average 38.1 ± 3.2 mM, n = 36). In accordance with this diverse [Cl-]i, GDPs induced either Cl--effluxes or Cl--influxes. In high [Cl-]i neurons with a negative Cl--driving force (DFCl) the [Cl-]i decreased after a GDP by 12.4 ± 3.4 mM (n = 10), while in low [Cl-]i neurons with a positive DFCl [Cl-]i increased by 4.4 ± 0.9 mM (n = 6). Inhibition of GDP activity by application of the AMPA receptor antagonist CNQX led to a [Cl-]i decrease to 24.7 ± 2.9 mM (n = 8). We conclude from these results, that Cl--fluxes via GABAA receptors during GDPs induced substantial [Cl-]i changes and that this activity-dependent ionic plasticity in neuronal [Cl-]i contributes to the functional consequences of GABAergic responses, emphasizing the concept that [Cl-]i is a state- and compartment-dependent parameter of individual cells.
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Affiliation(s)
- Aniello Lombardi
- Institute of Physiology, University Medical Center Mainz, Johannes Gutenberg University Mainz, Mainz, Germany
| | - Peter Jedlicka
- Interdisciplinary Centre for 3Rs in Animal Research, Faculty of Medicine, Justus Liebig University Giessen, Giessen, Germany.,Institute of Clinical Neuroanatomy, Neuroscience Center, Goethe University Frankfurt, Frankfurt, Germany
| | - Heiko J Luhmann
- Institute of Physiology, University Medical Center Mainz, Johannes Gutenberg University Mainz, Mainz, Germany
| | - Werner Kilb
- Institute of Physiology, University Medical Center Mainz, Johannes Gutenberg University Mainz, Mainz, Germany
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Mitchell SJ, Maguire EP, Cunningham L, Gunn BG, Linke M, Zechner U, Dixon CI, King SL, Stephens DN, Swinny JD, Belelli D, Lambert JJ. Early-life adversity selectively impairs α2-GABA A receptor expression in the mouse nucleus accumbens and influences the behavioral effects of cocaine. Neuropharmacology 2018; 141:98-112. [PMID: 30138693 PMCID: PMC6178871 DOI: 10.1016/j.neuropharm.2018.08.021] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2018] [Revised: 08/02/2018] [Accepted: 08/19/2018] [Indexed: 01/20/2023]
Abstract
Haplotypes of the Gabra2 gene encoding the α2-subunit of the GABAA receptor (GABAAR) are associated with drug abuse, suggesting that α2-GABAARs may play an important role in the circuitry underlying drug misuse. The genetic association of Gabra2 haplotypes with cocaine addiction appears to be evident primarily in individuals who had experienced childhood trauma. Given this association of childhood trauma, cocaine abuse and the Gabra2 haplotypes, we have explored in a mouse model of early life adversity (ELA) whether such events influence the behavioral effects of cocaine and if, as suggested by the human studies, α2-GABAARs in the nucleus accumbens (NAc) are involved in these perturbed behaviors. In adult mice prior ELA caused a selective decrease of accumbal α2-subunit mRNA, resulting in a selective decrease in the number and size of the α2-subunit (but not the α1-subunit) immunoreactive clusters in NAc core medium spiny neurons (MSNs). Functionally, in adult MSNs ELA decreased the amplitude and frequency of GABAAR-mediated miniature inhibitory postsynaptic currents (mIPSCs), a profile similar to that of α2 "knock-out" (α2-/-) mice. Behaviourally, adult male ELA and α2-/- mice exhibited an enhanced locomotor response to acute cocaine and blunted sensitisation upon repeated cocaine administration, when compared to their appropriate controls. Collectively, these findings reveal a neurobiological mechanism which may relate to the clinical observation that early trauma increases the risk for substance abuse disorder (SAD) in individuals harbouring haplotypic variations in the Gabra2 gene.
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Affiliation(s)
- Scott J Mitchell
- Division of Neuroscience, Medical Research Institute, Ninewells Hospital & Medical School, Dundee University, Dundee DD1 9SY, Scotland, United Kingdom
| | - Edward P Maguire
- Division of Neuroscience, Medical Research Institute, Ninewells Hospital & Medical School, Dundee University, Dundee DD1 9SY, Scotland, United Kingdom
| | - Linda Cunningham
- Division of Neuroscience, Medical Research Institute, Ninewells Hospital & Medical School, Dundee University, Dundee DD1 9SY, Scotland, United Kingdom
| | - Benjamin G Gunn
- Division of Neuroscience, Medical Research Institute, Ninewells Hospital & Medical School, Dundee University, Dundee DD1 9SY, Scotland, United Kingdom
| | - Matthias Linke
- Institute of Human Genetics, Mainz University, Medical Center, Mainz, Germany
| | - Ulrich Zechner
- Institute of Human Genetics, Mainz University, Medical Center, Mainz, Germany
| | - Claire I Dixon
- School of Psychology, University of Sussex, Falmer, Brighton, BN 9QG, United Kingdom
| | - Sarah L King
- School of Psychology, University of Sussex, Falmer, Brighton, BN 9QG, United Kingdom
| | - David N Stephens
- School of Psychology, University of Sussex, Falmer, Brighton, BN 9QG, United Kingdom
| | - Jerome D Swinny
- Institute for Biomedical & Biomolecular Sciences, School of Pharmacy & Biomedical Sciences, University of Portsmouth, Portsmouth PO1 2DT, United Kingdom.
| | - Delia Belelli
- Division of Neuroscience, Medical Research Institute, Ninewells Hospital & Medical School, Dundee University, Dundee DD1 9SY, Scotland, United Kingdom.
| | - Jeremy J Lambert
- Division of Neuroscience, Medical Research Institute, Ninewells Hospital & Medical School, Dundee University, Dundee DD1 9SY, Scotland, United Kingdom.
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Alvarez LD, Pecci A. Structure and dynamics of neurosteroid binding to the α 1β 2γ 2 GABA A receptor. J Steroid Biochem Mol Biol 2018; 182:72-80. [PMID: 29705269 DOI: 10.1016/j.jsbmb.2018.04.012] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/05/2018] [Revised: 04/17/2018] [Accepted: 04/23/2018] [Indexed: 11/23/2022]
Abstract
Neurosteroids are the principal endogenous modulators of the γ-Aminobutyric acid receptors (GABAARs), pentameric membrane-bound proteins that can be assembled from at least 19 subunits. In the most abundant GABAAR arrangement (α1β2γ2), neurosteroids can potentiate the GABA action as well as produce a direct activation of the channel. The recent crystal structures of neurosteroids bound to α homopentameric GABAAR reveal binding to five equivalent sites. However, these results have been obtained using receptors that are not physiologically relevant, suggesting a need to investigate neurosteroid binding to heteropentameric receptors that exist in the central nervous system. In a previous work, we predicted the neurosteroid binding site by applying molecular modeling methods on the β3 homopentamer. Here we construct a homology model of the transmembrane domain of the heteropentameric α1β2γ2 receptor and then, by combining docking and molecular dynamics simulations, we analyzed neurosteroid binding. Results show that the five neurosteroid cavities are conserved in the α1β2γ2 receptor and all of them are able to bind neurosteroids. Two different binding modes were detected depending on the identity of the residue at position 241 in the transmembrane helix 1. These theoretical findings provide microscopic insights into neurosteroid binding at the heteropentameric GABAAR. The existence of two classes of sites may be associated with how neurosteroids modulate GABAAR. Our finding would represent the essential first step to reach a comprehensive understanding of how these endogenous molecules regulate the central nervous system.
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Affiliation(s)
- Lautaro D Alvarez
- Universidad de Buenos Aires, Facultad de Ciencias Exactas y Naturales, Departamento de Química Orgánica, Buenos Aires, Argentina; CONICET - Universidad de Buenos Aires, UMYMFOR, Buenos Aires, Argentina.
| | - Adali Pecci
- Universidad de Buenos Aires, Facultad de Ciencias Exactas y Naturales, Departamento de Química Biológica, Buenos Aires, Argentina; CONICET - Universidad de Buenos Aires, IFIBYNE, Buenos Aires, Argentina
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Finn DA, Helms ML, Nipper MA, Cohen A, Jensen JP, Devaud LL. Sex differences in the synergistic effect of prior binge drinking and traumatic stress on subsequent ethanol intake and neurochemical responses in adult C57BL/6J mice. Alcohol 2018; 71:33-45. [PMID: 29966824 PMCID: PMC10957143 DOI: 10.1016/j.alcohol.2018.02.004] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2017] [Revised: 01/26/2018] [Accepted: 02/22/2018] [Indexed: 12/13/2022]
Abstract
Alcohol-use disorders (AUDs) are characterized by repeated episodes of binge drinking. Based on reports that exposure to predator odor stress (PS) consistently increases ethanol intake, the present studies examined whether prior binge drinking differentially altered responsivity to PS and subsequent ethanol intake in male and female mice, when compared to mice without prior binge exposure. Initial studies in naïve male and female C57BL/6J mice confirmed that 30-min exposure to dirty rat bedding significantly increased plasma corticosterone (CORT) levels and anxiety-related behavior, justifying the use of dirty rat bedding as PS in the subsequent drinking studies. Next, separate groups of male and female C57BL/6J mice received seven binge ethanol sessions (binge) or drank water (controls), followed by a 1-month period of abstinence. Then, 2-bottle choice ethanol intake (10% or 10E vs. water, 23 h/day) was measured in lickometer chambers for 4 weeks. After baseline intake stabilized, exposure to intermittent PS (2×/week × 2 weeks) significantly enhanced ethanol intake after the 2nd PS in male, but not female, binge mice vs. baseline and vs. the increase in controls. However, in a subgroup of females (with low baselines), PS produced a similar increase in 10E intake in control and binge mice vs. baseline. Analysis of lick behavior determined that the enhanced 10E intake in binge male mice and in the female low baseline subgroup was associated with a significant increase in 10E bout frequency and 10E licks throughout the circadian dark phase. Thus, PS significantly increased 10E intake and had a synergistic interaction with prior binge drinking in males, whereas PS produced a similar significant increase in 10E intake in the low baseline subgroup of binge and control females. Plasma CORT levels were increased significantly in both binge and control animals after PS. CORT levels at 24-h withdrawal from daily 10E intake were highest in the groups with elevated 10E licks (i.e., binge males and control females). At 24-h withdrawal, protein levels of GABAA receptor α1 subunit, corticotropin releasing factor receptor 1, and glucocorticoid receptor in prefrontal cortex (PFC) and hippocampus (HC) were differentially altered in the male and female mice vs. levels in separate groups of age-matched naïve mice, with more changes in HC than in PFC and in females than in males. Importantly, the sexually divergent changes in protein levels in PFC and HC add to evidence for sex differences in the neurochemical systems influenced by stress and binge drinking, and argue for sex-specific pharmacological strategies to treat AUD.
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Affiliation(s)
- Deborah A Finn
- Department of Behavioral Neuroscience, Oregon Health & Sciences University, Portland, OR, United States; VA Portland Health Care System, Portland, OR, United States.
| | - Melinda L Helms
- Department of Behavioral Neuroscience, Oregon Health & Sciences University, Portland, OR, United States
| | - Michelle A Nipper
- Department of Behavioral Neuroscience, Oregon Health & Sciences University, Portland, OR, United States
| | - Allison Cohen
- VA Portland Health Care System, Portland, OR, United States
| | - Jeremiah P Jensen
- Department of Behavioral Neuroscience, Oregon Health & Sciences University, Portland, OR, United States
| | - Leslie L Devaud
- School of Pharmacy, Pacific University, Hillsboro, OR, United States
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Zhao Y, Bijlsma EY, Verdouw PM, Garssen J, Groenink L. The contribution of contextual fear in the anxiolytic effect of chlordiazepoxide in the fear-potentiated startle test. Behav Brain Res 2018; 353:57-61. [PMID: 29969605 DOI: 10.1016/j.bbr.2018.06.035] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2018] [Revised: 06/28/2018] [Accepted: 06/29/2018] [Indexed: 10/28/2022]
Abstract
This study evaluated the extent to which a reduction in contextual fear contributes to the anxiolytic effect of benzodiazepines in the fear-potentiated startle response. To this end, chlordiazepoxide, an anxiolytic often used as positive control in preclinical drug studies, and zolpidem, known to have sedative properties and to be devoid of anxiolytic effects, were tested in two contexts: the same context as training had taken place and an alternative context. In addition, the level of muscle relaxation was assessed in a grip strength test. Chlordiazepoxide (2.5-10 mg/kg) decreased the fear-potentiated startle response, confirming its anxiolytic activity. In addition, it dose-dependently decreased the overall startle response in the same, but not the alternative context, and did not affect grip strength, indicating that chlordiazepoxide inhibits contextual fear in the absence of non-specific drug effects. Zolpidem (1.0-10 mg/kg) reduced the overall startle response in both contexts equally and decreased grip strength, indicating that its effects on fear-potentiated startle are due to non-specific drug effects, and not anxiolytic effects. The present findings show that chlordiazepoxide reduces contextual conditioned fear in the absence of non-specific drug effects. In addition, they show that training and testing rats in different contexts makes it possible to distinguish between cued, contextual and non-specific drug effects. As exaggerated contextual fear conditioning contributes to the fear generalization processes implicated in pathological anxiety, focus in screening of anxiolytic effects could be directed more towards the suppression of contextual fear and, therefore, this approach would be a valuable addition to standard preclinical screening.
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Affiliation(s)
- Yulong Zhao
- Division of Pharmacology, Utrecht Institute for Pharmaceutical Sciences (UIPS), Utrecht University, Universiteitsweg 99, 3584 CG, Utrecht, Netherlands
| | - Elisabeth Y Bijlsma
- Division of Pharmacology, Utrecht Institute for Pharmaceutical Sciences (UIPS), Utrecht University, Universiteitsweg 99, 3584 CG, Utrecht, Netherlands.
| | - P Monika Verdouw
- Division of Pharmacology, Utrecht Institute for Pharmaceutical Sciences (UIPS), Utrecht University, Universiteitsweg 99, 3584 CG, Utrecht, Netherlands
| | - Johan Garssen
- Division of Pharmacology, Utrecht Institute for Pharmaceutical Sciences (UIPS), Utrecht University, Universiteitsweg 99, 3584 CG, Utrecht, Netherlands
| | - Lucianne Groenink
- Division of Pharmacology, Utrecht Institute for Pharmaceutical Sciences (UIPS), Utrecht University, Universiteitsweg 99, 3584 CG, Utrecht, Netherlands
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45
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Murlidaran S, Brannigan G. Physical Accuracy Leads to Biological Relevance: Best Practices For Simulating Ligand-Gated Ion Channels Interacting With General Anesthetics. Methods Enzymol 2018; 602:3-24. [PMID: 29588036 DOI: 10.1016/bs.mie.2018.02.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
Abstract
Efforts to detect binding modes of general anesthetics (GAs) for pentameric ligand-gated ion channels (pLGICs) are often complicated by a large number of indicated sites, as well as the challenges of ranking sites by affinity and determining which sites are occupied at clinical concentrations. Physics-based computational methods offer a powerful route for determining affinities of ligands to isolated binding sites, but preserving accuracy is essential. This chapter describes a step-by-step approach to multiple methods for identifying candidate sites and quantifying binding affinities and also discusses limitations and common pitfalls.
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46
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Feng HJ, Forman SA. Comparison of αβδ and αβγ GABA A receptors: Allosteric modulation and identification of subunit arrangement by site-selective general anesthetics. Pharmacol Res 2017; 133:289-300. [PMID: 29294355 DOI: 10.1016/j.phrs.2017.12.031] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/18/2017] [Revised: 12/28/2017] [Accepted: 12/29/2017] [Indexed: 12/27/2022]
Abstract
GABAA receptors play a dominant role in mediating inhibition in the mature mammalian brain, and defects of GABAergic neurotransmission contribute to the pathogenesis of a variety of neurological and psychiatric disorders. Two types of GABAergic inhibition have been described: αβγ receptors mediate phasic inhibition in response to transient high-concentrations of synaptic GABA release, and αβδ receptors produce tonic inhibitory currents activated by low-concentration extrasynaptic GABA. Both αβδ and αβγ receptors are important targets for general anesthetics, which induce apparently different changes both in GABA-dependent receptor activation and in desensitization in currents mediated by αβγ vs. αβδ receptors. Many of these differences are explained by correcting for the high agonist efficacy of GABA at most αβγ receptors vs. much lower efficacy at αβδ receptors. The stoichiometry and subunit arrangement of recombinant αβγ receptors are well established as β-α-γ-β-α, while those of αβδ receptors remain controversial. Importantly, some potent general anesthetics selectively bind in transmembrane inter-subunit pockets of αβγ receptors: etomidate acts at β+/α- interfaces, and the barbiturate R-5-allyl-1-methyl-5-(m-trifluoromethyl-diazirynylphenyl) barbituric acid (R-mTFD-MPAB) acts at α+/β- and γ+/β- interfaces. Thus, these drugs are useful as structural probes in αβδ receptors formed from free subunits or concatenated subunit assemblies designed to constrain subunit arrangement. Although a definite conclusion cannot be drawn, studies using etomidate and R-mTFD-MPAB support the idea that recombinant α1β3δ receptors may share stoichiometry and subunit arrangement with α1β3γ2 receptors.
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Affiliation(s)
- Hua-Jun Feng
- Department of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital, and Department of Anesthesia, Harvard Medical School, Boston, MA 02114, USA.
| | - Stuart A Forman
- Department of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital, and Department of Anesthesia, Harvard Medical School, Boston, MA 02114, USA.
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Delahanty RJ, Zhang Y, Bichell TJ, Shen W, Verdier K, Macdonald RL, Xu L, Boyd K, Williams J, Kang JQ. Beyond Epilepsy and Autism: Disruption of GABRB3 Causes Ocular Hypopigmentation. Cell Rep 2017; 17:3115-3124. [PMID: 28009282 DOI: 10.1016/j.celrep.2016.11.067] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2016] [Revised: 09/26/2016] [Accepted: 11/21/2016] [Indexed: 01/12/2023] Open
Abstract
Reduced ocular pigmentation is common in Angelman syndrome (AS) and Prader-Willi syndrome (PWS) and is long thought to be caused by OCA2 deletion. GABRB3 is located in the 15q11-13 region flanked by UBE3A, GABRA5, GABRG3, and OCA2. Mutations in GABRB3 have frequently been associated with epilepsy and autism, consistent with its role in neurodevelopment. We report here a robust phenotype in the mouse in which deletion of Gabrb3 alone causes nearly complete loss of retinal pigmentation due to atrophied melanosomes, as evidenced by electron microscopy. Using exome and RNA sequencing, we confirmed that only the Gabrb3 gene was disrupted while the Oca2 gene was intact. However, mRNA abundance of Oca2 and other genes adjacent to Gabrb3 is substantially reduced in Gabrb3-/- mice, suggesting complex transcriptional regulation in this region. These results suggest that impairment in GABRB3 downregulates OCA2 and indirectly causes ocular hypopigmentation and visual defects in AS and PWS.
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Affiliation(s)
- Ryan J Delahanty
- Division of Epidemiology, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN 37212, USA; Department of Human Genetics, Vanderbilt University Medical Center, Nashville, TN 37212, USA
| | - Yanfeng Zhang
- Division of Epidemiology, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN 37212, USA
| | - Terry Jo Bichell
- Department of Neurology, Vanderbilt University Medical Center, Nashville, TN 37212, USA
| | - Wangzhen Shen
- Department of Neurology, Vanderbilt University Medical Center, Nashville, TN 37212, USA
| | - Kelienne Verdier
- Department of Neurology, Vanderbilt University Medical Center, Nashville, TN 37212, USA
| | - Robert L Macdonald
- Department of Neurology, Vanderbilt University Medical Center, Nashville, TN 37212, USA; Department of Molecular Physiology and Biophysics, Vanderbilt University Medical Center, Nashville, TN 37212, USA; Department of Pharmacology, Vanderbilt University Medical Center, Nashville, TN 37212, USA; Vanderbilt Brain Institute, Vanderbilt University Medical Center, Nashville, TN 37212, USA
| | - Lili Xu
- Department of Neurology, Vanderbilt University Medical Center, Nashville, TN 37212, USA
| | - Kelli Boyd
- Pathology Microbiology and Immunology, Vanderbilt University Medical Center, Nashville, TN 37212, USA
| | - Janice Williams
- Vanderbilt Electron Microscopy Core, Vanderbilt University Medical Center, Nashville, TN 37212, USA
| | - Jing-Qiong Kang
- Department of Neurology, Vanderbilt University Medical Center, Nashville, TN 37212, USA; Vanderbilt Brain Institute, Vanderbilt University Medical Center, Nashville, TN 37212, USA.
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Chaffiol A, Ishii M, Cao Y, Mangel SC. Dopamine Regulation of GABA A Receptors Contributes to Light/Dark Modulation of the ON-Cone Bipolar Cell Receptive Field Surround in the Retina. Curr Biol 2017; 27:2600-2609.e4. [PMID: 28844643 DOI: 10.1016/j.cub.2017.07.063] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2017] [Revised: 05/22/2017] [Accepted: 07/27/2017] [Indexed: 10/19/2022]
Abstract
Cone bipolar cells are interneurons that receive synaptic input from cone photoreceptor cells and provide the output of the first synaptic layer of the retina. These cells exhibit center-surround receptive fields, a prototype of lateral inhibition between neighboring sensory cells in which stimulation of the receptive field center excites the cell whereas stimulation of the surrounding region laterally inhibits the cell. This fundamental sensory coding mechanism facilitates spatial discrimination and detection of stimulus edges. However, although it is well established that the receptive field surround is strongest when ambient or background illumination is most intense, e.g., at midday, and that the surround is minimal following maintained darkness, the synaptic mechanisms that produce and modulate the surround have not been resolved. Using electrical recording of bipolar cells under experimental conditions in which the cells exhibited surround light responses, and light and electron microscopic immunocytochemistry, we show in the rabbit retina that bright-light-induced activation of dopamine D1 receptors located on ON-center cone bipolar cell dendrites increases the expression and activity of GABAA receptors on the dendrites of the cells and that surround light responses depend on endogenous GABAA receptor activation. We also show that maintained darkness and D1 receptor blockade following maintained illumination and D1 receptor activation result in minimal GABAA receptor expression and activity and greatly diminished surrounds. Modulation of the D1/GABAA receptor signaling pathway of ON-cBC dendrites by the ambient light level facilitates detection of spatial details on bright days and large dim objects on moonless nights.
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Affiliation(s)
- Antoine Chaffiol
- Department of Neuroscience, The Ohio State University College Of Medicine, Columbus, OH 43210, USA
| | - Masaaki Ishii
- Department of Neuroscience, The Ohio State University College Of Medicine, Columbus, OH 43210, USA
| | - Yu Cao
- Department of Neuroscience, The Ohio State University College Of Medicine, Columbus, OH 43210, USA
| | - Stuart C Mangel
- Department of Neuroscience, The Ohio State University College Of Medicine, Columbus, OH 43210, USA.
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Rasmusson AM, Marx CE, Pineles SL, Locci A, Scioli-Salter ER, Nillni YI, Liang JJ, Pinna G. Neuroactive steroids and PTSD treatment. Neurosci Lett 2017; 649:156-163. [PMID: 28215878 DOI: 10.1016/j.neulet.2017.01.054] [Citation(s) in RCA: 63] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2016] [Revised: 01/22/2017] [Accepted: 01/23/2017] [Indexed: 01/08/2023]
Abstract
This review highlights early efforts to translate pre-clinical and clinical findings regarding the role of neuroactive steroids in stress adaptation and PTSD into new therapeutics for PTSD. Numerous studies have demonstrated PTSD-related alterations in resting levels or the reactivity of neuroactive steroids and their targets. These studies also have demonstrated substantial variability in the dysfunction of specific neuroactive steroid systems among PTSD subpopulations. These variabilities have been related to the developmental timing of trauma, severity and type of trauma, genetic background, sex, reproductive state, lifestyle influences such as substance use and exercise, and the presence of comorbid conditions such as depression and chronic pain. Nevertheless, large naturalistic studies and a small placebo-controlled interventional study have revealed generally positive effects of glucocorticoid administration in preventing PTSD after trauma, possibly mediated by glucocorticoid receptor-mediated effects on other targets that impact PTSD risk, including other neuroactive steroid systems. In addition, clinical and preclinical studies show that administration of glucocorticoids, 17β-estradiol, and GABAergic neuroactive steroids or agents that enhance their synthesis can facilitate extinction and extinction retention, depending on dose and timing of dose in relation to these complex PTSD-relevant recovery processes. This suggests that clinical trials designed to test neuroactive steroid therapeutics in PTSD may benefit from such considerations; typical continuous dosing regimens may not be optimal. In addition, validated and clinically accessible methods for identifying specific neuroactive steroid system abnormalities at the individual level are needed to optimize both clinical trial design and precision medicine based treatment targeting.
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Affiliation(s)
- Ann M Rasmusson
- National Center for PTSD, Women's Health Science Division, Department of Veterans Affairs 150 South Huntington Avenue, Boston, MA 02135, USA; VA Boston Healthcare System 150 South Huntington Avenue, Boston, MA 02135, USA; Boston University School of Medicine 72 E Concord St, Boston, MA 02118, USA.
| | - Christine E Marx
- Durham VA Medical Center, VA Mid-Atlantic MIRECC,and Duke University Medical Center, 508 Fulton Street, Durham, NC 27705, USA
| | - Suzanne L Pineles
- National Center for PTSD, Women's Health Science Division, Department of Veterans Affairs 150 South Huntington Avenue, Boston, MA 02135, USA; Boston University School of Medicine 72 E Concord St, Boston, MA 02118, USA
| | - Andrea Locci
- The Psychiatric Institute, Department of Psychiatry, University of Illinois at Chicago, 1601 W. Taylor Str., Chicago, IL 60612, USA
| | - Erica R Scioli-Salter
- VA Boston Healthcare System 150 South Huntington Avenue, Boston, MA 02135, USA; Boston University School of Medicine 72 E Concord St, Boston, MA 02118, USA
| | - Yael I Nillni
- National Center for PTSD, Women's Health Science Division, Department of Veterans Affairs 150 South Huntington Avenue, Boston, MA 02135, USA; Boston University School of Medicine 72 E Concord St, Boston, MA 02118, USA
| | - Jennifer J Liang
- Boston University School of Medicine 72 E Concord St, Boston, MA 02118, USA
| | - Graziano Pinna
- The Psychiatric Institute, Department of Psychiatry, University of Illinois at Chicago, 1601 W. Taylor Str., Chicago, IL 60612, USA
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50
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Albers HE, Walton JC, Gamble KL, McNeill JK, Hummer DL. The dynamics of GABA signaling: Revelations from the circadian pacemaker in the suprachiasmatic nucleus. Front Neuroendocrinol 2017; 44:35-82. [PMID: 27894927 PMCID: PMC5225159 DOI: 10.1016/j.yfrne.2016.11.003] [Citation(s) in RCA: 69] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/30/2016] [Revised: 10/16/2016] [Accepted: 11/22/2016] [Indexed: 12/31/2022]
Abstract
Virtually every neuron within the suprachiasmatic nucleus (SCN) communicates via GABAergic signaling. The extracellular levels of GABA within the SCN are determined by a complex interaction of synthesis and transport, as well as synaptic and non-synaptic release. The response to GABA is mediated by GABAA receptors that respond to both phasic and tonic GABA release and that can produce excitatory as well as inhibitory cellular responses. GABA also influences circadian control through the exclusively inhibitory effects of GABAB receptors. Both GABA and neuropeptide signaling occur within the SCN, although the functional consequences of the interactions of these signals are not well understood. This review considers the role of GABA in the circadian pacemaker, in the mechanisms responsible for the generation of circadian rhythms, in the ability of non-photic stimuli to reset the phase of the pacemaker, and in the ability of the day-night cycle to entrain the pacemaker.
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Affiliation(s)
- H Elliott Albers
- Center for Behavioral Neuroscience, Atlanta, GA 30302, United States; Neuroscience Institute, Georgia State University, Atlanta, GA 30302, United States.
| | - James C Walton
- Center for Behavioral Neuroscience, Atlanta, GA 30302, United States; Neuroscience Institute, Georgia State University, Atlanta, GA 30302, United States
| | - Karen L Gamble
- Department of Psychiatry and Behavioral Neurobiology, University of Alabama at Birmingham, Birmingham, AL 35294, United States
| | - John K McNeill
- Center for Behavioral Neuroscience, Atlanta, GA 30302, United States; Neuroscience Institute, Georgia State University, Atlanta, GA 30302, United States
| | - Daniel L Hummer
- Center for Behavioral Neuroscience, Atlanta, GA 30302, United States; Department of Psychology, Morehouse College, Atlanta, GA 30314, United States
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