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Lee JH, Chae EJ, Park SJ, Choi JW. Label-free detection of γ-aminobutyric acid based on silicon nanowire biosensor. NANO CONVERGENCE 2019; 6:13. [PMID: 31041617 PMCID: PMC6491525 DOI: 10.1186/s40580-019-0184-3] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/14/2018] [Accepted: 03/29/2019] [Indexed: 05/24/2023]
Abstract
γ-Aminobutyric acid (GABA) is an important inhibitory neurotransmitter in the central nervous system (CNS), which acts as a major biomarker for neurological disorders such as Parkinson's disease and Meningitis. To this end, the precise measurement of GABA molecule arisen as an important subject for the effective diagnosis and treatment of neurological disorders. However, yet highly sensitive biosensor systems which can analyze a wide range of GABA molecule in a fast response manner have not been reported. In this study, for the first time, a silicon nanowire field-effect transistor (FET) device based immunosensor was developed to detect GABA molecule. Zig-zag shaped silicon nanowires has been fabricated by electron beam lithography and the electrical property p-type FET device was validated through semiconductor analyzer. The optimal immobilizing condition of antibody against GABA molecule was determined by the fluorescent signal measurement. Various concentrations of GABA ranging from 970 fM to 9.7 μM were sensitively measured by conductance change on silicon nanowire-based through the immunoreactions. Further, owing to the ease of miniaturization and label-free system, we believe that the suggested device system has a potential to be utilized for an implantable biosensor to detect neurotransmitter in the brain and can create new opportunities in the field of diagnosis and treatment of neurological disorders.
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Affiliation(s)
- Jin-Ho Lee
- Department of Chemical and Biomolecular Engineering, Sogang University, Seoul, 04107 Korea
- Department of Chemistry and Chemical Biology, Rutgers, The State University of New Jersey, Piscataway, NJ 08854 USA
| | - Eun-Ji Chae
- Department of Chemical and Biomolecular Engineering, Sogang University, Seoul, 04107 Korea
| | - Soo-jeong Park
- Research Center for Disease Biophysics of Sogang-Harvard, Sogang University, Seoul, 04107 Korea
| | - Jeong-Woo Choi
- Department of Chemical and Biomolecular Engineering, Sogang University, Seoul, 04107 Korea
- Research Center for Disease Biophysics of Sogang-Harvard, Sogang University, Seoul, 04107 Korea
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2
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Ma S, Hangya B, Leonard CS, Wisden W, Gundlach AL. Dual-transmitter systems regulating arousal, attention, learning and memory. Neurosci Biobehav Rev 2018; 85:21-33. [PMID: 28757457 PMCID: PMC5747977 DOI: 10.1016/j.neubiorev.2017.07.009] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2017] [Accepted: 07/16/2017] [Indexed: 01/12/2023]
Abstract
An array of neuromodulators, including monoamines and neuropeptides, regulate most behavioural and physiological traits. In the past decade, dramatic progress has been made in mapping neuromodulatory circuits, in analysing circuit dynamics, and interrogating circuit function using pharmacogenetic, optogenetic and imaging methods This review will focus on several distinct neural networks (acetylcholine/GABA/glutamate; histamine/GABA; orexin/glutamate; and relaxin-3/GABA) that originate from neural hubs that regulate wakefulness and related attentional and cognitive processes, and highlight approaches that have identified dual transmitter roles in these behavioural functions. Modulation of these different neural networks might be effective treatments of diseases related to arousal/sleep dysfunction and of cognitive dysfunction in psychiatric and neurodegenerative disorders.
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Affiliation(s)
- Sherie Ma
- The Florey Institute of Neuroscience and Mental Health, Parkville, Victoria, Australia; Florey Department of Neuroscience and Mental Health, The University of Melbourne, Victoria, Australia.
| | - Balázs Hangya
- 'Lendület' Laboratory of Systems Neuroscience, Department of Cellular and Network Neurobiology, Institute of Experimental Medicine, Hungarian Academy of Sciences, Budapest, Hungary
| | | | - William Wisden
- Department of Life Sciences, Imperial College London, London, UK
| | - Andrew L Gundlach
- The Florey Institute of Neuroscience and Mental Health, Parkville, Victoria, Australia; Florey Department of Neuroscience and Mental Health, The University of Melbourne, Victoria, Australia; Department of Anatomy and Neuroscience, The University of Melbourne, Victoria, Australia.
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3
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Bönnighausen J, Gebhard D, Kröger C, Hadeler B, Tumforde T, Lieberei R, Bergemann J, Schäfer W, Bormann J. Disruption of the GABA shunt affects mitochondrial respiration and virulence in the cereal pathogen Fusarium graminearum. Mol Microbiol 2015; 98:1115-32. [PMID: 26305050 DOI: 10.1111/mmi.13203] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/24/2015] [Indexed: 01/07/2023]
Abstract
The cereal pathogen Fusarium graminearum threatens food and feed production worldwide. It reduces the yield and poisons the remaining kernels with mycotoxins, notably deoxynivalenol (DON). We analyzed the importance of gamma-aminobutanoic acid (GABA) metabolism for the life cycle of this fungal pathogen. GABA metabolism in F. graminearum is partially regulated by the global nitrogen regulator AreA. Genetic disruption of the GABA shunt by deletion of two GABA transaminases renders the pathogen unable to utilize the plant stress metabolites GABA and putrescine. The mutants showed increased sensitivity against oxidative stress, GABA accumulation in the mycelium, downregulation of two key enzymes of the TCA cycle, disturbed potential gradient in the mitochondrial membrane and lower mitochondrial oxygen consumption. In contrast, addition of GABA to the wild type resulted in its rapid turnover and increased mitochondrial steady state oxygen consumption. GABA concentrations are highly upregulated in infected wheat tissues. We conclude that GABA is metabolized by the pathogen during infection increasing its energy production, whereas the mutants accumulate GABA intracellularly resulting in decreased energy production. Consequently, the GABA mutants are strongly reduced in virulence but, because of their DON production, are able to cross the rachis node.
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Affiliation(s)
- Jakob Bönnighausen
- Biocenter Klein Flottbek, Department of Molecular Phytopathology and Genetics, University of Hamburg, Ohnhorststr. 18, D-22609, Hamburg, Germany
| | - Daniel Gebhard
- Department of Life Sciences, Albstadt-Sigmaringen University of Applied Sciences, Anton-Günther-Str. 51, D-72488, Sigmaringen, Germany
| | - Cathrin Kröger
- Biocenter Klein Flottbek, Department of Molecular Phytopathology and Genetics, University of Hamburg, Ohnhorststr. 18, D-22609, Hamburg, Germany
| | - Birgit Hadeler
- Biocenter Klein Flottbek, Department of Molecular Phytopathology and Genetics, University of Hamburg, Ohnhorststr. 18, D-22609, Hamburg, Germany
| | - Thomas Tumforde
- Biocenter Klein Flottbek, Department of Applied Plant Ecology and Biodiversity of Useful Plants, University of Hamburg, Ohnhorststr. 18, D-22609, Hamburg, Germany
| | - Reinhard Lieberei
- Biocenter Klein Flottbek, Department of Applied Plant Ecology and Biodiversity of Useful Plants, University of Hamburg, Ohnhorststr. 18, D-22609, Hamburg, Germany
| | - Jörg Bergemann
- Department of Life Sciences, Albstadt-Sigmaringen University of Applied Sciences, Anton-Günther-Str. 51, D-72488, Sigmaringen, Germany
| | - Wilhelm Schäfer
- Biocenter Klein Flottbek, Department of Molecular Phytopathology and Genetics, University of Hamburg, Ohnhorststr. 18, D-22609, Hamburg, Germany
| | - Jörg Bormann
- Biocenter Klein Flottbek, Department of Molecular Phytopathology and Genetics, University of Hamburg, Ohnhorststr. 18, D-22609, Hamburg, Germany
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4
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Wakefulness Is Governed by GABA and Histamine Cotransmission. Neuron 2015; 87:164-78. [PMID: 26094607 PMCID: PMC4509551 DOI: 10.1016/j.neuron.2015.06.003] [Citation(s) in RCA: 118] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2015] [Revised: 04/29/2015] [Accepted: 05/27/2015] [Indexed: 12/17/2022]
Abstract
Histaminergic neurons in the tuberomammilary nucleus (TMN) of the hypothalamus form a widely projecting, wake-active network that sustains arousal. Yet most histaminergic neurons contain GABA. Selective siRNA knockdown of the vesicular GABA transporter (vgat, SLC32A1) in histaminergic neurons produced hyperactive mice with an exceptional amount of sustained wakefulness. Ablation of the vgat gene throughout the TMN further sharpened this phenotype. Optogenetic stimulation in the caudate-putamen and neocortex of “histaminergic” axonal projections from the TMN evoked tonic (extrasynaptic) GABAA receptor Cl− currents onto medium spiny neurons and pyramidal neurons. These currents were abolished following vgat gene removal from the TMN area. Thus wake-active histaminergic neurons generate a paracrine GABAergic signal that serves to provide a brake on overactivation from histamine, but could also increase the precision of neocortical processing. The long range of histamine-GABA axonal projections suggests that extrasynaptic inhibition will be coordinated over large neocortical and striatal areas. Histaminergic axons corelease GABA into the neocortex and striatum The released GABA produces slow tonic inhibition Reducing vgat expression in histaminergic neurons increases wakefulness Histamine-GABA axons will coordinate tonic inhibition over large cortical areas
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5
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Opioid system and Alzheimer's disease. Neuromolecular Med 2012; 14:91-111. [PMID: 22527793 DOI: 10.1007/s12017-012-8180-3] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2011] [Accepted: 04/04/2012] [Indexed: 12/15/2022]
Abstract
The opioid system may be involved in the pathogenesis of AD, including cognitive impairment, hyperphosphorylated tau, Aβ production, and neuroinflammation. Opioid receptors influence the regulation of neurotransmitters such as acetylcholine, norepinephrine, GABA, glutamate, and serotonin which have been implicated in the pathogenesis of AD. Opioid system has a close relation with Aβ generation since dysfunction of opioid receptors retards the endocytosis and degradation of BACE1 and γ-secretase and upregulates BACE1 and γ-secretase, and subsequently, the production of Aβ. Conversely, activation of opioid receptors increases the endocytosis of BACE1 and γ-secretase and downregulates BACE1 and γ-secretase, limiting the production of Aβ. The dysfunction of opioid system (opioid receptors and opioid peptides) may contribute to hyperphosphorylation of tau and neuroinflammation, and accounts for the degeneration of cholinergic neurons and cognitive impairment. Thus, the opioid system is potentially related to AD pathology and may be a very attractive drug target for novel pharmacotherapies of AD.
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Wang L, He X, Guo Y, Xu J, Shao S. pH-Responsive chromogenic-sensing molecule based on bis(indolyl)methene for the highly selective recognition of aspartate and glutamate. Beilstein J Org Chem 2011; 7:218-21. [PMID: 21448262 PMCID: PMC3063074 DOI: 10.3762/bjoc.7.29] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2010] [Accepted: 01/19/2011] [Indexed: 01/13/2023] Open
Abstract
Bis(indolyl)methene displays high selectivity and sensitivity for aspartate and glutamate in water-containing medium based on the proton transfer signaling mode. The presence of acid can easily induce proton transfer to the basic H-bond acceptor moiety, which modulates the internal charge transfer state of the bis(indolyl)methene skeleton and gives rise to dramatic change in color. The detection limits for aspartate and glutamate were 0.80 ppm and 1.12 ppm, respectively.
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Affiliation(s)
- Litao Wang
- Key Laboratory of Chemistry of Northwestern Plant Resources and Key Laboratory for Natural Medicine of Gansu Province, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000, P. R. China
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7
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Späth A, König B. Ditopic crown ether–guanidinium ion receptors for the molecular recognition of amino acids and small peptides. Tetrahedron 2010. [DOI: 10.1016/j.tet.2010.01.028] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Kovacic P, Pozos RS, Draskovich CD. Unifying electrostatic mechanism for receptor-ligand activity. J Recept Signal Transduct Res 2008; 27:411-31. [PMID: 18097940 DOI: 10.1080/10799890701699686] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
A prior article in skeletal form proposed an electrostatic mechanism for receptor-ligand activity. The present review provides an elaboration, including supporting evidence. The fundamental aspect entails the presence of molecular electrostatic potential associated with ions and dipoles in the ligand. The ligand can be regarded as an electrical link that joins prevalent electrostatic fields present in the surrounding protein matrix. The exact role of these fields is speculative. One possibility is to function as conduits for electrons and radicals in cell signaling. There is increasing support for important participation of these species in signal transduction. There might also be a favorable influence on energetics involving the electron transfer process. A summary of receptor biology is also provided, including receptors for acetylcholine (nicotinic and muscarinic), GABA, adrenergic, and glutamate.
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Affiliation(s)
- Peter Kovacic
- Department of Chemistry, San Diego State University, San Diego, California 921812, USA.
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9
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Wang MD, Rahman M, Zhu D. Protons inhibit Cl- conductance by direct or allosteric interaction with the GABA-binding site in the rat recombinant alpha1beta2gamma2L and alpha1beta2 GABAA receptor. Eur J Pharmacol 2005; 528:1-6. [PMID: 16325175 DOI: 10.1016/j.ejphar.2005.11.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2005] [Revised: 10/24/2005] [Accepted: 11/01/2005] [Indexed: 10/25/2022]
Abstract
Functional roles of external pH on the Cl- conductance were examined on Xenopus oocytes expressing rat recombinant alpha1beta2gamma2L and alpha1beta2 GABAA receptors. Acidic pH inhibited GABA-response in a reversible and concentration-dependent manner, significantly increasing the EC50 without appreciably changing the slope or maximal currents induced by GABA in the alpha1beta2gamma2L and alpha1beta2 receptors. In contrast, protonation did not influence the pentobarbital-gated currents in the alpha1beta2gamma2L receptors, suggesting that protons do not modulate channel activity by directly affecting the channel gating process. Protons competitively inhibited the bicuculline-induced antagonism on GABA in the alpha1beta2gamma2L receptors. The data support the hypothesis that protons inhibit GABAA receptor function by direct or allosteric interaction with the GABA-binding site.
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Affiliation(s)
- Ming-De Wang
- Umeå Neurosteroid Research Center, Department of Clinical Science, Obstetrics and Gynecology, Umeå University, Bldg 5B, 5th floor, S-901 85 Umeå, Sweden.
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10
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Huang RQ, Chen Z, Dillon GH. Molecular Basis for Modulation of Recombinant α1β2γ2 GABAA Receptors by Protons. J Neurophysiol 2004; 92:883-94. [PMID: 15028749 DOI: 10.1152/jn.01040.2003] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
We have previously shown that extracellular protons inhibit recombinant and native GABAA receptors. In this report, we studied the site(s) and mechanism by which protons modulate the GABAA receptor. Whole cell GABA-activated currents were recorded from human embryonic kidney (HEK) 293 cells expressing recombinant α1β2γ2 GABAA receptors. Protons competitively inhibited the response to GABA and bicuculline. In contrast, change in pH did not influence direct gating of the channel by pentobarbital, and it did not influence spontaneous channel openings in α1(L264T)β2γ2 receptors, suggesting pH does not modulate channel activity by affecting the channel gating process directly. To test the hypothesis that protons modulate GABAA receptors at the ligand binding site, we systemically mutated N-terminal residues known to be involved in GABA binding and assessed effects of pH on these mutant receptors. Site-specific mutation of β2 Y205 to F or α1 F64 to A, both of which are known to influence GABA binding, significantly reduced pH sensitivity of the GABA response. These mutations did not affect Zn2+ sensitivity, suggesting that H+ and Zn2+ do not share a common site of action. Additional experiments further tested this possibility. Treatment with the histidine-modifying reagent diethylpyrocarbonate (DEPC) reduced Zn2+-mediated inhibition of GABAA receptors but had no effect on proton-induced inhibition of GABA currents. In addition, mutation of residues known to be involved in Zn2+ modulation had no effect on pH modulation of GABAA receptors. Our results support the hypothesis that protons inhibit GABAA receptor function by direct or allosteric interaction with the GABA binding site. In addition, the sites of action of H+ and Zn2+ in GABAA receptors are distinct.
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Affiliation(s)
- Ren-Qi Huang
- Dept. of Pharmacology and Neuroscience, University of North Texas Health Science Center, 3500 Camp Bowie Blvd., Fort Worth, TX 76107, USA.
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11
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Yoshikawa T, Watanabe A, Ishitsuka Y, Nakaya A, Nakatani N. Identification of multiple genetic loci linked to the propensity for "behavioral despair" in mice. Genome Res 2002; 12:357-66. [PMID: 11875023 DOI: 10.1101/gr.222602] [Citation(s) in RCA: 87] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
The forced swim test (FST) and tail suspension test (TST) are widely used and well established screening paradigms for antidepressants. A variety of antidepressive agents are known to reduce immobility time in both FST and TST. To identify genetic determinants of immobility duration in both tests, we analyzed 560 F2 mice from an intercross between C57BL/6 (B6) and C3H/He (C3) strains. Composite interval mapping revealed five major loci (suggestive and significant linkage) affecting immobility in the FST, and four loci for the TST. The quantitative trait loci (QTL) on chromosomes 8 and 11 overlap between the two behavioral measures. Genome-wide interaction analysis, which was developed to identify locus pairs that may contribute epistatically to a phenotype, detected two pairs of chromosomal loci for the TST. The QTL on chromosome 11 and its associated epistatic TST-QTL on chromosome X encode gamma-aminobutyric acid type A (GABA(A)) receptor subunits as candidates. Sequence and expression analyses of these genes from the two parental strains revealed a significantly lower expression of the alpha1 subunit gene in the frontal cortex of B6 mice compared to C3 mice. The present quantitative trait study should open up avenues for identifying novel molecular targets for antidepressants and unraveling the complex genetic mechanisms of depressive and anxiety disorders.
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Affiliation(s)
- Takeo Yoshikawa
- Laboratory for Molecular Psychiatry, Brain Science Institute, RIKEN, Wako, Saitama 351-0198, Japan.
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12
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Huang RQ, Dillon GH. Effect of extracellular pH on GABA-activated current in rat recombinant receptors and thin hypothalamic slices. J Neurophysiol 1999; 82:1233-43. [PMID: 10482743 DOI: 10.1152/jn.1999.82.3.1233] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
We studied the effects of extracellular pH (pHo) on gamma-aminobutyric acid (GABA)-mediated Cl- current in rat hypothalamic neurons and recombinant type-A GABA (GABA(A)) receptors stably expressed in human embryonic kidney cells (HEK 293), using whole cell and outside-out patch-clamp recordings. In alpha3beta2gamma2s receptors, acidic pH decreased, whereas alkaline pH increased the response to GABA in a reversible and concentration-dependent manner. Acidification shifted the GABA concentration-response curve to the right, significantly increasing the EC50 for GABA without appreciably changing the slope or maximal current induced by GABA. We obtained similar effects of pH in alpha1beta2gamma2 receptors and in GABA-activated currents recorded from thin hypothalamic brain slices. In outside-out patches recorded from alpha3beta2gamma2 recombinant receptors, membrane patches were exposed to 5 microM GABA at control (7.3), acidic (6.4), or alkaline (8.4) pH. GABA activated main and subconductance states of 24 and 16 pS, respectively, in alpha3beta2gamma2 receptors. Alkaline pH(o) increased channel opening frequency and decreased the duration of the long closed state, resulting in an increase in open probability (from 0.0801 +/- 0.015 in pH 7.3 to 0.138 +/- 0.02 in pH 8.4). Exposure of the channels to acidic pH(o) had the opposite effects on open probability (decreased to 0.006 +/- 0.0001). Taken together, our results indicate that the function of GABA(A) receptors is modulated by extracellular pH. The proton effect is similar in recombinant and native receptors and is dependent on GABA concentration. In addition, the effect appears to be independent of the alpha-subunit isoform, and is due to the ability of H+ to alter the frequency of channel opening. Our findings indicate that GABAergic signaling in the CNS may be significantly altered during conditions that increase or decrease pH.
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Affiliation(s)
- R Q Huang
- Department of Pharmacology, University of North Texas Health Science Center at Fort Worth, Fort Worth, Texas 76107, USA
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Arnaud-Neu F, Fuangswasdi S, Notti A, Pappalardo S, Parisi M. Molekulare Gefäße auf Calix[5]aren-Basis für Alkylammonium-Ionen. Angew Chem Int Ed Engl 1998. [DOI: 10.1002/(sici)1521-3757(19980116)110:1/2<120::aid-ange120>3.0.co;2-n] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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14
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Affiliation(s)
- M Selmanoff
- Department of Physiology, University of Maryland, School of Medicine, Baltimore 21201-1559.
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15
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Abstract
gamma-Aminobutyric acid (GABA)A receptors for the inhibitory neurotransmitter GABA are likely to be found on most, if not all, neurons in the brain and spinal cord. They appear to be the most complicated of the superfamily of ligand-gated ion channels in terms of the large number of receptor subtypes and also the variety of ligands that interact with specific sites on the receptors. There appear to be at least 11 distinct sites on GABAA receptors for these ligands.
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Affiliation(s)
- G A Johnston
- Adrien Albert Laboratory of Medicinal Chemistry, Department of Pharmacology, University of Sydney, NSW, Australia
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Roberts E. Pregneolone--from Selye to Alzheimer and a model of the pregnenolone sulfate binding site on the GABAA receptor. Biochem Pharmacol 1995; 49:1-16. [PMID: 7840775 DOI: 10.1016/0006-2952(94)00258-n] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Affiliation(s)
- E Roberts
- Department of Neurobiochemistry, Beckman Research Institute of the City of Hope, Duarte, CA 91010
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Näsman B, Olsson T, Seckl JR, Eriksson S, Viitanen M, Bucht G, Carlstrom K. Abnormalities in adrenal androgens, but not of glucocorticoids, in early Alzheimer's disease. Psychoneuroendocrinology 1995; 20:83-94. [PMID: 7838905 DOI: 10.1016/0306-4530(94)e0044-a] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
In an attempt to evaluate possible adrenal abnormalities in Alzheimer's disease (AD), prestimulus levels and ACTH-stimulated serum levels of steroid hormones, corticosteroid-binding globulin (CBG), and insulin-like growth factor I (IGF-I) were measured in 18 patients with early AD (8 men, 10 women; 74.6 +/- 6.5 years, mean +/- SD) and 19 healthy controls (10 men, 9 women; 74.2 +/- 7.6 years, mean +/- SD). Steroid hormone levels were measured before and after an intravenous bolus injection of 250 micrograms ACTH. AD per se had an independent influence on hormone levels when evaluated in MANOVA models. AD patients had significantly higher prestimulus levels of dehydroepiandrosterone and androstenedione (p = .04 and p = .003, respectively) with accentuated differences after ACTH (p = .02 and p < .001 for peak responses, respectively). Serum levels of cortisol, CBG, free cortisol, 17 alpha-hydroxyprogesterone (17 alpha-OHP), and IGF-I did not differ between groups. These abnormalities may have implications for neuronal degeneration as well as for behavioural symptoms in AD.
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Affiliation(s)
- B Näsman
- Department of Geriatric Medicine, University Hospital of Northern Sweden, Umeå
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18
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Abstract
A fragile balance between excitation and inhibition maintains the normal functioning of the CNS. The dominant inhibitory neurotransmitter of the mammalian brain is GABA, which acts mainly through GABAA and GABAB receptors. Small changes in GABA-mediated inhibition can alter neuronal excitability profoundly and, therefore, a wide range of compounds that clearly modify GABAA-receptor function are used clinically as anesthetics or for the treatment of various nervous system disorders. Recent findings have started to unravel the operation of central GABA synapses where inhibitory events appear to result from the synchronous opening of only tens of GABAA receptors activated by a saturating concentration of GABA. Such properties of GABA synapses impose certain constraints on the physiological and pharmacological modulation of inhibition in the brain.
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Affiliation(s)
- I Mody
- Dept of Anesthesiology and Pain Management, UT Southwestern Medical Center, Dallas
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