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Delhaye M, LeDue J, Robinson K, Xu Q, Zhang Q, Oku S, Zhang P, Craig AM. Adaptation of Magnified Analysis of the Proteome for Excitatory Synaptic Proteins in Varied Samples and Evaluation of Cell Type-Specific Distributions. J Neurosci 2024; 44:e1291232024. [PMID: 38360747 PMCID: PMC10993037 DOI: 10.1523/jneurosci.1291-23.2024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2023] [Revised: 02/02/2024] [Accepted: 02/07/2024] [Indexed: 02/17/2024] Open
Abstract
Growing evidence suggests a remarkable diversity and complexity in the molecular composition of synapses, forming the basis for the brain to execute complex behaviors. Hence, there is considerable interest in visualizing the spatial distribution of such molecular diversity at individual synapses within intact brain circuits. Yet this task presents significant technical challenges. Expansion microscopy approaches have revolutionized our view of molecular anatomy. However, their use to study synapse-related questions outside of the labs developing them has been limited. Here we independently adapted a version of Magnified Analysis of the Proteome (MAP) and present a step-by-step protocol for visualizing over 40 synaptic proteins in brain circuits. Surprisingly, our findings show that the advantage of MAP over conventional immunolabeling was primarily due to improved antigen recognition and secondarily physical expansion. Furthermore, we demonstrated the versatile use of MAP in brains perfused with paraformaldehyde or fresh-fixed with formalin and in formalin-fixed paraffin-embedded tissue. These tests expand the potential applications of MAP to combinations with slice electrophysiology or clinical pathology specimens. Using male and female mice expressing YFP-ChR2 exclusively in interneurons, we revealed a distinct composition of AMPA and NMDA receptors and Shank family members at synapses on hippocampal interneurons versus on pyramidal neurons. Quantitative single synapse analyses yielded comprehensive cell type distributions of synaptic proteins and their relationships. These findings exemplify the value of the versatile adapted MAP procedure presented here as an accessible tool for the broad neuroscience community to unravel the complexity of the "synaptome" across brain circuits and disease states.
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Affiliation(s)
- Mathias Delhaye
- Djavad Mowafaghian Centre for Brain Health and Department of Psychiatry, University of British Columbia, Vancouver, British Columbia V6T 2B5, Canada
| | - Jeffrey LeDue
- Djavad Mowafaghian Centre for Brain Health and Department of Psychiatry, University of British Columbia, Vancouver, British Columbia V6T 2B5, Canada
| | - Kaylie Robinson
- Djavad Mowafaghian Centre for Brain Health and Department of Psychiatry, University of British Columbia, Vancouver, British Columbia V6T 2B5, Canada
| | - Qin Xu
- Department of Neurosciences, School of Medicine, Case Western Reserve University, Cleveland, Ohio 44106
| | - Qian Zhang
- Department of Neurosciences, School of Medicine, Case Western Reserve University, Cleveland, Ohio 44106
| | - Shinichiro Oku
- Djavad Mowafaghian Centre for Brain Health and Department of Psychiatry, University of British Columbia, Vancouver, British Columbia V6T 2B5, Canada
| | - Peng Zhang
- Djavad Mowafaghian Centre for Brain Health and Department of Psychiatry, University of British Columbia, Vancouver, British Columbia V6T 2B5, Canada
- Department of Neurosciences, School of Medicine, Case Western Reserve University, Cleveland, Ohio 44106
| | - Ann Marie Craig
- Djavad Mowafaghian Centre for Brain Health and Department of Psychiatry, University of British Columbia, Vancouver, British Columbia V6T 2B5, Canada
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Cation-Chloride Cotransporters KCC2 and NKCC1 as Therapeutic Targets in Neurological and Neuropsychiatric Disorders. Molecules 2023; 28:molecules28031344. [PMID: 36771011 PMCID: PMC9920462 DOI: 10.3390/molecules28031344] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2022] [Revised: 01/21/2023] [Accepted: 01/25/2023] [Indexed: 02/04/2023] Open
Abstract
Neurological diseases including Alzheimer's, Huntington's disease, Parkinson's disease, Down syndrome and epilepsy, and neuropsychiatric disorders such as schizophrenia, are conditions that affect not only individuals but societies on a global scale. Current therapies offer a means for small symptomatic relief, but recently there has been increasing demand for therapeutic alternatives. The γ-aminobutyric acid (GABA)ergic signaling system has been investigated for developing new therapies as it has been noted that any dysfunction or changes to this system can contribute to disease progression. Expression of the K-Cl-2 (KCC2) and N-K-C1-1 (NKCC1) cation-chloride cotransporters (CCCs) has recently been linked to the disruption of GABAergic activity by affecting the polarity of GABAA receptor signaling. KCC2 and NKCC1 play a part in multiple neurological and neuropsychiatric disorders, making them a target of interest for potential therapies. This review explores current research suggesting the pathophysiological role and therapeutic importance of KCC2 and NKCC1 in neuropsychiatric and neurological disorders.
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Li H, Xu G, Yuan G. Effects of an Armillaria mellea Polysaccharide on Learning and Memory of D-Galactose-Induced Aging Mice. Front Pharmacol 2022; 13:919920. [PMID: 35924065 PMCID: PMC9341523 DOI: 10.3389/fphar.2022.919920] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2022] [Accepted: 06/02/2022] [Indexed: 11/13/2022] Open
Abstract
Armillaria mellea has been known and used in traditional medicine in East Asia for hundreds of years. It has already been reported that A. mellea extracts have various pharmacological effects, and the polysaccharides of A. mellea exhibit antioxidant and anti-apoptotic activities. In this study, a water-soluble polysaccharide (AMP-N-a-1), with an average molecular weight of 17 kD, was isolated and purified from the water extract of A. mellea using DEAE-52, Sepharose CL-4B, and Sephadex G-100 column chromatography. AMP-N-a-1 was mainly composed of Man (1.65%), Glca (1.64%), Rha (1.82%), Gala (2.49%), Glc (90.48%), Gal (0.89%), Xyl (0.42%), and Ara (0.61%). AMP-N-a-1 was used to study the effect on the learning and memory of mice and its underlying mechanisms. The results showed that AMP-N-a-1 could significantly increase the activities of catalase (CAT) and superoxide dismutase (SOD) and reduce the content of nitric oxide (NO) in mouse brain tissue. Meanwhile, AMP-N-a-1 could reduce the contents of norepinephrine (NE) and dopamine (DA) but could increase the content of 5-hydroxytryptamine (5-HT) in mouse brain tissue. In addition, the immunofluorescence experiment showed that AMP-N-a-1 could promote the proliferation of hippocampal dentate gyrus neurons. The above results indicate that AMP-N-a-1 can significantly improve the learning and memory of mice, and the mechanism may be that AMP-N-a-1 can participate in the regulation of learning and memory through a variety of ways.
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Affiliation(s)
- Hongyu Li
- School of Pharmacy, Beihua University, Jilin, China
- School of Basic Medicine, Jiamusi University, Jiamusi, China
| | - Guangyu Xu
- School of Pharmacy, Beihua University, Jilin, China
| | - Guangxin Yuan
- School of Pharmacy, Beihua University, Jilin, China
- *Correspondence: Guangxin Yuan,
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Sente A, Desai R, Naydenova K, Malinauskas T, Jounaidi Y, Miehling J, Zhou X, Masiulis S, Hardwick SW, Chirgadze DY, Miller KW, Aricescu AR. Differential assembly diversifies GABA A receptor structures and signalling. Nature 2022; 604:190-194. [PMID: 35355020 PMCID: PMC7612593 DOI: 10.1038/s41586-022-04517-3] [Citation(s) in RCA: 37] [Impact Index Per Article: 18.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2021] [Accepted: 02/04/2022] [Indexed: 01/07/2023]
Abstract
Type A γ-aminobutyric acid receptors (GABAARs) are pentameric ligand-gated chloride channels that mediate fast inhibitory signalling in neural circuits1,2 and can be modulated by essential medicines including general anaesthetics and benzodiazepines3. Human GABAAR subunits are encoded by 19 paralogous genes that can, in theory, give rise to 495,235 receptor types. However, the principles that govern the formation of pentamers, the permutational landscape of receptors that may emerge from a subunit set and the effect that this has on GABAergic signalling remain largely unknown. Here we use cryogenic electron microscopy to determine the structures of extrasynaptic GABAARs assembled from α4, β3 and δ subunits, and their counterparts incorporating γ2 instead of δ subunits. In each case, we identified two receptor subtypes with distinct stoichiometries and arrangements, all four differing from those previously observed for synaptic, α1-containing receptors4-7. This, in turn, affects receptor responses to physiological and synthetic modulators by creating or eliminating ligand-binding sites at subunit interfaces. We provide structural and functional evidence that selected GABAAR arrangements can act as coincidence detectors, simultaneously responding to two neurotransmitters: GABA and histamine. Using assembly simulations and single-cell RNA sequencing data8,9, we calculated the upper bounds for receptor diversity in recombinant systems and in vivo. We propose that differential assembly is a pervasive mechanism for regulating the physiology and pharmacology of GABAARs.
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Affiliation(s)
| | - Rooma Desai
- Department of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | | | - Tomas Malinauskas
- Division of Structural Biology, Wellcome Centre for Human Genetics, University of Oxford, Oxford, UK
| | - Youssef Jounaidi
- Department of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | | | - Xiaojuan Zhou
- Department of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Simonas Masiulis
- MRC Laboratory of Molecular Biology, Cambridge, UK
- Materials and Structural Analysis Division, Thermo Fisher Scientific, Achtseweg Noord, Eindhoven, Netherlands
| | | | | | - Keith W Miller
- Department of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA.
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Luquin E, Paternain B, Zugasti I, Santomá C, Mengual E. Stereological estimations and neurochemical characterization of neurons expressing GABAA and GABAB receptors in the rat pedunculopontine and laterodorsal tegmental nuclei. Brain Struct Funct 2022; 227:89-110. [PMID: 34510281 PMCID: PMC8741722 DOI: 10.1007/s00429-021-02375-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2020] [Accepted: 08/31/2021] [Indexed: 11/29/2022]
Abstract
To better understand GABAergic transmission at two targets of basal ganglia downstream projections, the pedunculopontine (PPN) and laterodorsal (LDT) tegmental nuclei, the anatomical localization of GABAA and GABAB receptors was investigated in both nuclei. Specifically, the total number of neurons expressing the GABAA receptor γ2 subunit (GABAAR γ2) and the GABAB receptor R2 subunit (GABAB R2) in PPN and LDT was estimated using stereological methods, and the neurochemical phenotype of cells expressing each subunit was also determined. The mean number of non-cholinergic cells expressing GABAAR γ2 was 9850 ± 1856 in the PPN and 8285 ± 962 in the LDT, whereas those expressing GABAB R2 were 7310 ± 1970 and 9170 ± 1900 in the PPN and LDT, respectively. In addition, all cholinergic neurons in both nuclei co-expressed GABAAR γ2 and 95-98% of them co-expressed GABAB R2. Triple labeling using in situ hybridization revealed that 77% of GAD67 mRNA-positive cells in the PPT and 49% in the LDT expressed GABAAR γ2, while 90% (PPN) and 65% (LDT) of Vglut2 mRNA-positive cells also expressed GABAAR γ2. In contrast, a similar proportion (~2/3) of glutamatergic and GABAergic cells co-expressed GABAB R2 in both nuclei. The heterogeneous distribution of GABAAR and GABABR among non-cholinergic cells in PPN and LDT may give rise to physiological differences within each neurochemical subpopulation. In addition, the dissimilar proportion of GABAAR γ2-expressing glutamatergic and GABAergic neurons in the PPN and LDT may contribute to some of the functional differences found between the two nuclei.
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Affiliation(s)
- Esther Luquin
- Department of Pathology, Anatomy, and Physiology, School of Medicine, University of Navarra, Ed. Los Castaños, Irunlarrea 1, 31008 Pamplona, Spain
- IdiSNA, Navarra Institute for Health Research, 31008 Pamplona, Spain
| | - Beatriz Paternain
- Department of Pathology, Anatomy, and Physiology, School of Medicine, University of Navarra, Ed. Los Castaños, Irunlarrea 1, 31008 Pamplona, Spain
- IdiSNA, Navarra Institute for Health Research, 31008 Pamplona, Spain
| | - Inés Zugasti
- Department of Pathology, Anatomy, and Physiology, School of Medicine, University of Navarra, Ed. Los Castaños, Irunlarrea 1, 31008 Pamplona, Spain
- IdiSNA, Navarra Institute for Health Research, 31008 Pamplona, Spain
| | - Carmen Santomá
- Department of Pathology, Anatomy, and Physiology, School of Medicine, University of Navarra, Ed. Los Castaños, Irunlarrea 1, 31008 Pamplona, Spain
- IdiSNA, Navarra Institute for Health Research, 31008 Pamplona, Spain
| | - Elisa Mengual
- Department of Pathology, Anatomy, and Physiology, School of Medicine, University of Navarra, Ed. Los Castaños, Irunlarrea 1, 31008 Pamplona, Spain
- IdiSNA, Navarra Institute for Health Research, 31008 Pamplona, Spain
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Lee TJ, Zanello AF, Morrison TR, Ricci LA, Melloni RH. Valproate selectively suppresses adolescent anabolic/androgenic steroid-induced aggressive behavior: implications for a role of hypothalamic γ-aminobutyric acid neural signaling. Behav Pharmacol 2021; 32:295-307. [PMID: 33595952 DOI: 10.1097/fbp.0000000000000616] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Pubertal male Syrian hamsters (Mesocricetus auratus) treated with anabolic/androgenic steroids (AASs) during adolescence (P27-P56) display a highly intense aggressive phenotype that shares many behavioral similarities with pathological aggression in youth. Anticonvulsant drugs like valproate that enhance the activity of the γ-aminobutyric acid (GABA) neural system in the brain have recently gained acceptance as a primary treatment for pathological aggression. This study examined whether valproate would selectively suppress adolescent AAS-induced aggressive behavior and whether GABA neural signaling through GABAA subtype receptors in the latero-anterior hypothalamus (LAH; an area of convergence for developmental and neuroplastic changes that underlie aggression in hamsters) modulate the aggression-suppressing effect of this anticonvulsant medication. Valproate (1.0-10.0 mg/kg, intraperitoneal) selectively suppressed the aggressive phenotype in a dose-dependent fashion, with the effective anti-aggressive effects beginning at 5 mg/kg, intraperitoneally. Microinfusion of the GABAA receptor antagonist bicuculline (7.0-700 ng) into the LAH reversed valproate's suppression of AAS-induced aggression in a dose-dependent fashion. At the 70 ng dose of bicuculline, animals expressed the highly aggressive baseline phenotype normally observed in AAS-treated animals. These studies provide preclinical evidence that the anticonvulsant valproate selectively suppresses adolescent, AAS-induced aggression and that this suppression is modulated, in part, by GABA neural signaling within the LAH.
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Affiliation(s)
- Terrence J Lee
- Program in Behavioral Neuroscience, Department of Psychology, Northeastern University, Boston, Massachusetts, USA
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Absalom NL, Liao VWY, Kothur K, Indurthi DC, Bennetts B, Troedson C, Mohammad SS, Gupta S, McGregor IS, Bowen MT, Lederer D, Mary S, De Waele L, Jansen K, Gill D, Kurian MA, McTague A, Møller RS, Ahring PK, Dale RC, Chebib M. Gain-of-function GABRB3 variants identified in vigabatrin-hypersensitive epileptic encephalopathies. Brain Commun 2020; 2:fcaa162. [PMID: 33585817 PMCID: PMC7869430 DOI: 10.1093/braincomms/fcaa162] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2020] [Revised: 07/31/2020] [Accepted: 08/28/2020] [Indexed: 01/06/2023] Open
Abstract
Variants in the GABRB3 gene encoding the β3-subunit of the γ-aminobutyric acid type A ( receptor are associated with various developmental and epileptic encephalopathies. Typically, these variants cause a loss-of-function molecular phenotype whereby γ-aminobutyric acid has reduced inhibitory effectiveness leading to seizures. Drugs that potentiate inhibitory GABAergic activity, such as nitrazepam, phenobarbital or vigabatrin, are expected to compensate for this and thereby reduce seizure frequency. However, vigabatrin, a drug that inhibits γ-aminobutyric acid transaminase to increase tonic γ-aminobutyric acid currents, has mixed success in treating seizures in patients with GABRB3 variants: some patients experience seizure cessation, but there is hypersensitivity in some patients associated with hypotonia, sedation and respiratory suppression. A GABRB3 variant that responds well to vigabatrin involves a truncation variant (p.Arg194*) resulting in a clear loss-of-function. We hypothesized that patients with a hypersensitive response to vigabatrin may exhibit a different γ-aminobutyric acid A receptor phenotype. To test this hypothesis, we evaluated the phenotype of de novo variants in GABRB3 (p.Glu77Lys and p.Thr287Ile) associated with patients who are clinically hypersensitive to vigabatrin. We introduced the GABRB3 p.Glu77Lys and p.Thr287Ile variants into a concatenated synaptic and extrasynaptic γ-aminobutyric acid A receptor construct, to resemble the γ-aminobutyric acid A receptor expression by a patient heterozygous for the GABRB3 variant. The mRNA of these constructs was injected into Xenopus oocytes and activation properties of each receptor measured by two-electrode voltage clamp electrophysiology. Results showed an atypical gain-of-function molecular phenotype in the GABRB3 p.Glu77Lys and p.Thr287Ile variants characterized by increased potency of γ-aminobutyric acid A without change to the estimated maximum open channel probability, deactivation kinetics or absolute currents. Modelling of the activation properties of the receptors indicated that either variant caused increased chloride flux in response to low concentrations of γ-aminobutyric acid that mediate tonic currents. We therefore propose that the hypersensitivity reaction to vigabatrin is a result of GABRB3 variants that exacerbate GABAergic tonic currents and caution is required when prescribing vigabatrin. In contrast, drug strategies increasing tonic currents in loss-of-function variants are likely to be a safe and effective therapy. This study demonstrates that functional genomics can explain beneficial and adverse anti-epileptic drug effects, and propose that vigabatrin should be considered in patients with clear loss-of-function GABRB3 variants.
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Affiliation(s)
- Nathan L Absalom
- Faculty of Medicine and Health, School of Pharmacy, Brain and Mind Centre, The University of Sydney, Sydney, New South Wales 2006, Australia
| | - Vivian W Y Liao
- Faculty of Medicine and Health, School of Pharmacy, Brain and Mind Centre, The University of Sydney, Sydney, New South Wales 2006, Australia
| | - Kavitha Kothur
- Kids Neuroscience Centre at The Children’s Hospital at Westmead, Westmead, New South Wales 2145, Australia
| | - Dinesh C Indurthi
- Faculty of Medicine and Health, School of Pharmacy, Brain and Mind Centre, The University of Sydney, Sydney, New South Wales 2006, Australia
| | - Bruce Bennetts
- Department of Molecular Genetics, The Children’s Hospital at Westmead, Westmead, New South Wales 2145, Australia
- Discipline of Paediatrics and Adolescent Health, The Children's Hospital at Westmead Clinical School, The University of Sydney, 2145, Australia
| | - Christopher Troedson
- T.Y. Nelson Department of Neurology and Neurosurgery, The Children's Hospital at Westmead, Westmead, New South Wales 2145, Australia
| | - Shekeeb S Mohammad
- Kids Neuroscience Centre at The Children’s Hospital at Westmead, Westmead, New South Wales 2145, Australia
| | - Sachin Gupta
- T.Y. Nelson Department of Neurology and Neurosurgery, The Children's Hospital at Westmead, Westmead, New South Wales 2145, Australia
| | - Iain S McGregor
- Faculty of Science, Lambert Initiative for Cannabinoid Therapeutics, Brain and Mind Centre, The University of Sydney, Sydney, New South Wales 2006, Australia
| | - Michael T Bowen
- Faculty of Science, Lambert Initiative for Cannabinoid Therapeutics, Brain and Mind Centre, The University of Sydney, Sydney, New South Wales 2006, Australia
| | - Damien Lederer
- Institute of Pathology and Genetics, Center for Human Genetics, Gosselies 6041, Belgium
| | - Sandrine Mary
- Institute of Pathology and Genetics, Center for Human Genetics, Gosselies 6041, Belgium
| | - Liesbeth De Waele
- Department of Development and Regeneration, KULeuven, Leuven 3000, Belgium
| | - Katrien Jansen
- Department of Development and Regeneration, KULeuven, Leuven 3000, Belgium
| | - Deepak Gill
- Kids Neuroscience Centre at The Children’s Hospital at Westmead, Westmead, New South Wales 2145, Australia
| | - Manju A Kurian
- Molecular Neurosciences, UCL Great Ormond Street Institute of Child Health, London WC1E 6BT, UK
- Department of Neurology, Great Ormond Street Hospital for Children, London WC1N 3JH, UK
| | - Amy McTague
- Molecular Neurosciences, UCL Great Ormond Street Institute of Child Health, London WC1E 6BT, UK
- Department of Neurology, Great Ormond Street Hospital for Children, London WC1N 3JH, UK
| | - Rikke S Møller
- Department of Epilepsy Genetics and Personalized Medicine, Danish Epilepsy Centre, Dianalund 4293, Denmark
- Department of Regional Health Research, University of Southern Denmark, Odense 5230, Denmark
| | - Philip K Ahring
- Faculty of Medicine and Health, School of Pharmacy, Brain and Mind Centre, The University of Sydney, Sydney, New South Wales 2006, Australia
| | - Russell C Dale
- Kids Neuroscience Centre at The Children’s Hospital at Westmead, Westmead, New South Wales 2145, Australia
| | - Mary Chebib
- Faculty of Medicine and Health, School of Pharmacy, Brain and Mind Centre, The University of Sydney, Sydney, New South Wales 2006, Australia
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Zhang Y, Huang Q, Chen Y, Peng X, Wang Y, Li S, Wu J, Luo C, Gong W, Yin B, Xiao J, Zhou W, Peng F, Long H. Parthenolide, an NF-κB inhibitor, alleviates peritoneal fibrosis by suppressing the TGF-β/Smad pathway. Int Immunopharmacol 2019; 78:106064. [PMID: 31838448 DOI: 10.1016/j.intimp.2019.106064] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2019] [Revised: 11/14/2019] [Accepted: 11/17/2019] [Indexed: 10/25/2022]
Abstract
Transforming growth factor (TGF)-β/Smad signalling plays a central role in the pathogenesis of peritoneal fibrosis related to peritoneal dialysis (PD). Parthenolide (PTL), a naturally occurring phytochemical, is isolated from the shoots of feverfew (Tanacetum parthenium) and displays analgesia, anti-inflammation and anticancer activities. In this study, we examined the therapeutic potential of PTL on PD-related peritoneal fibrosis induced by daily intraperitoneal injection of 4.25% dextrose-containing PD fluid (PDF) in vivo and TGF-β1-induced epithelial-mesenchymal transition (EMT) in vitro. PTL was administered daily before PDF injection or after 14 days of PDF injection. Both PTL treatments showed a protective effect on peritoneal fibrosis and prevented peritoneal dysfunction. Similarly, PTL suppressed the expression of fibrotic markers (fibronectin and collagen I) and restored the expression of the epithelial marker (E-cadherin) in TGF-β1-treated HMrSV5 cells. Furthermore, PTL inhibited TGF-β1-induced Smad2 and Smad3 phosphorylation and nuclear translocation but did not influence Smad1/5/9 phosphorylation or activate other downstream signalling pathways of TGF-β1, including AKT, extracellular signal-regulated kinase (ERK) or p38. In conclusion, PTL treatment may represent an effective and novel therapy for PD-associated peritoneal fibrosis by suppressing the TGF-β/Smad pathway.
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Affiliation(s)
- Ying Zhang
- Department of Nephrology, Zhujiang Hospital, Southern Medical University, Guangzhou 510280, China; Department of Nephrology, The Second Affiliated Hospital of Guangzhou Medical University, Guangzhou 510260, China
| | - Qianyin Huang
- Department of Nephrology, Zhujiang Hospital, Southern Medical University, Guangzhou 510280, China
| | - Yihua Chen
- Department of Nephrology, Zhujiang Hospital, Southern Medical University, Guangzhou 510280, China
| | - Xuan Peng
- Department of Nephrology, The Second Affiliated Hospital of Guangzhou Medical University, Guangzhou 510260, China
| | - Yuxian Wang
- Department of Gerontology, Zhujiang Hospital, Southern Medical University, Guangzhou 510280, China
| | - Shuting Li
- Department of Nephrology, Zhujiang Hospital, Southern Medical University, Guangzhou 510280, China
| | - Jiayu Wu
- Department of Nephrology, Zhujiang Hospital, Southern Medical University, Guangzhou 510280, China
| | - Congwei Luo
- Department of Nephrology, Zhujiang Hospital, Southern Medical University, Guangzhou 510280, China
| | - Wangqiu Gong
- Department of Nephrology, Zhujiang Hospital, Southern Medical University, Guangzhou 510280, China
| | - Bohui Yin
- Department of Nephrology, Zhujiang Hospital, Southern Medical University, Guangzhou 510280, China
| | - Jing Xiao
- Department of Nephrology, Zhujiang Hospital, Southern Medical University, Guangzhou 510280, China
| | - Weidong Zhou
- Department of Nephrology, Zhujiang Hospital, Southern Medical University, Guangzhou 510280, China.
| | - Fenfen Peng
- Department of Nephrology, Zhujiang Hospital, Southern Medical University, Guangzhou 510280, China.
| | - Haibo Long
- Department of Nephrology, Zhujiang Hospital, Southern Medical University, Guangzhou 510280, China.
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Developmental Changes in Serotonergic Modulation of GABAergic Synaptic Transmission and Postsynaptic GABA A Receptor Composition in the Cerebellar Nuclei. THE CEREBELLUM 2019; 17:346-358. [PMID: 29349630 DOI: 10.1007/s12311-018-0922-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Outputs from the cerebellar nuclei (CN) are important for generating and controlling movement. The activity of CN neurons is controlled not only by excitatory inputs from mossy and climbing fibers and by γ-aminobutyric acid (GABA)-based inhibitory transmission from Purkinje cells in the cerebellar cortex but is also modulated by inputs from other brain regions, including serotonergic fibers that originate in the dorsal raphe nuclei. We examined the modulatory effects of serotonin (5-HT) on GABAergic synapses during development, using rat cerebellar slices. As previously reported, 5-HT presynaptically decreased the amplitudes of stimulation-evoked inhibitory postsynaptic currents (IPSCs) in CN neurons, with this effect being stronger in slices from younger animals (postnatal days [P] 11-13) than in slices from older animals (P19-21). GABA release probabilities accordingly exhibited significant decreases from P11-13 to P19-21. Although there was a strong correlation between the GABA release probability and the magnitude of 5-HT-induced inhibition, manipulating the release probability by changing extracellular Ca2+ concentrations failed to control the extent of 5-HT-induced inhibition. We also found that the IPSCs exhibited slower kinetics at P11-13 than at P19-21. Pharmacological and molecular biological tests revealed that IPSC kinetics were largely determined by the prevalence of α1 subunits within GABAA receptors. In summary, pre- and postsynaptic developmental changes in serotonergic modulation and GABAergic synaptic transmission occur during the second to third postnatal weeks and may significantly contribute to the formation of normal adult cerebellar function.
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Olsen RW. GABA A receptor: Positive and negative allosteric modulators. Neuropharmacology 2018; 136:10-22. [PMID: 29407219 PMCID: PMC6027637 DOI: 10.1016/j.neuropharm.2018.01.036] [Citation(s) in RCA: 189] [Impact Index Per Article: 31.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2017] [Revised: 01/23/2018] [Accepted: 01/25/2018] [Indexed: 12/11/2022]
Abstract
gamma-Aminobutyric acid (GABA)-mediated inhibitory neurotransmission and the gene products involved were discovered during the mid-twentieth century. Historically, myriad existing nervous system drugs act as positive and negative allosteric modulators of these proteins, making GABA a major component of modern neuropharmacology, and suggesting that many potential drugs will be found that share these targets. Although some of these drugs act on proteins involved in synthesis, degradation, and membrane transport of GABA, the GABA receptors Type A (GABAAR) and Type B (GABABR) are the targets of the great majority of GABAergic drugs. This discovery is due in no small part to Professor Norman Bowery. Whereas the topic of GABABR is appropriately emphasized in this special issue, Norman Bowery also made many insights into GABAAR pharmacology, the topic of this article. GABAAR are members of the ligand-gated ion channel receptor superfamily, a chloride channel family of a dozen or more heteropentameric subtypes containing 19 possible different subunits. These subtypes show different brain regional and subcellular localization, age-dependent expression, and potential for plastic changes with experience including drug exposure. Not only are GABAAR the targets of agonist depressants and antagonist convulsants, but most GABAAR drugs act at other (allosteric) binding sites on the GABAAR proteins. Some anxiolytic and sedative drugs, like benzodiazepine and related drugs, act on GABAAR subtype-dependent extracellular domain sites. General anesthetics including alcohols and neurosteroids act at GABAAR subunit-interface trans-membrane sites. Ethanol at high anesthetic doses acts on GABAAR subtype-dependent trans-membrane domain sites. Ethanol at low intoxicating doses acts at GABAAR subtype-dependent extracellular domain sites. Thus GABAAR subtypes possess pharmacologically specific receptor binding sites for a large group of different chemical classes of clinically important neuropharmacological agents. This article is part of the "Special Issue Dedicated to Norman G. Bowery".
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Affiliation(s)
- Richard W Olsen
- Department of Molecular & Medical Pharmacology, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA.
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11
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Dieriks BV, Dean JM, Aronica E, Waldvogel HJ, Faull RLM, Curtis MA. Differential Fatty Acid-Binding Protein Expression in Persistent Radial Glia in the Human and Sheep Subventricular Zone. Dev Neurosci 2018; 40:145-161. [PMID: 29680832 DOI: 10.1159/000487633] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2017] [Accepted: 01/18/2018] [Indexed: 01/19/2023] Open
Abstract
Fatty acid-binding proteins (FABPs) are a family of transport proteins that facilitate intracellular transport of fatty acids. Despite abundant expression in the brain, the role that FABPs play in the process of cell proliferation and migration in the subventricular zone (SVZ) remains unclear. Our results provide a detailed characterisation of FABP3, 5, and 7 expression in adult and fetal human and sheep SVZ. High FABP5 expression was specifically observed in the adult human SVZ and co-labelled with polysialylated neural cell adhesion molecule (PSA-NCAM), glial fibrillary acidic protein (GFAP), GFAPδ, and proliferating cell nuclear antigen (PCNA), indicating a role for FABP5 throughout the full maturation process of astrocytes and neuroblasts. Some FABP5+ cells had a radial glial-like appearance and co-labelled with the radial glia markers vimentin (40E-C) and GFAP. In the fetal human brain, FABP5 was expressed by radial glia cells throughout the ventricular zone. In contrast, radial glia-like cells in sheep highly expressed FABP3. Taken together, these differences highlight the species-specific expression profile of FABPs in the SVZ. In this study, we demonstrate the distribution of FABP in the adult human SVZ and fetal ventricular zone and reveal its expression on persistent radial glia that may be involved in adult neurogenesis.
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Affiliation(s)
- Birger Victor Dieriks
- Department of Anatomy and Medical Imaging, Faculty of Medical and Health Science, University of Auckland, Auckland, New Zealand.,Centre for Brain Research, Faculty of Medical and Health Science, University of Auckland, Auckland, New Zealand
| | - Justin M Dean
- Department of Physiology, Faculty of Medical and Health Science, University of Auckland, Auckland, New Zealand
| | - Eleonora Aronica
- Department of (Neuro)Pathology, Academic Medical Center, Amsterdam, the Netherlands
| | - Henry J Waldvogel
- Department of Anatomy and Medical Imaging, Faculty of Medical and Health Science, University of Auckland, Auckland, New Zealand.,Centre for Brain Research, Faculty of Medical and Health Science, University of Auckland, Auckland, New Zealand
| | - Richard L M Faull
- Department of Anatomy and Medical Imaging, Faculty of Medical and Health Science, University of Auckland, Auckland, New Zealand.,Centre for Brain Research, Faculty of Medical and Health Science, University of Auckland, Auckland, New Zealand
| | - Maurice A Curtis
- Department of Anatomy and Medical Imaging, Faculty of Medical and Health Science, University of Auckland, Auckland, New Zealand.,Centre for Brain Research, Faculty of Medical and Health Science, University of Auckland, Auckland, New Zealand
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12
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Ge Y, Kang Y, Cassidy RM, Moon KM, Lewis R, Wong ROL, Foster LJ, Craig AM. Clptm1 Limits Forward Trafficking of GABA A Receptors to Scale Inhibitory Synaptic Strength. Neuron 2018; 97:596-610.e8. [PMID: 29395912 DOI: 10.1016/j.neuron.2017.12.038] [Citation(s) in RCA: 48] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2017] [Revised: 11/17/2017] [Accepted: 12/22/2017] [Indexed: 12/11/2022]
Abstract
In contrast with numerous studies of glutamate receptor-associated proteins and their involvement in the modulation of excitatory synapses, much less is known about mechanisms controlling postsynaptic GABAA receptor (GABAAR) numbers. Using tandem affinity purification from tagged GABAAR γ2 subunit transgenic mice and proteomic analysis, we isolated several GABAAR-associated proteins, including Cleft lip and palate transmembrane protein 1 (Clptm1). Clptm1 interacted with all GABAAR subunits tested and promoted GABAAR trapping in the endoplasmic reticulum. Overexpression of Clptm1 reduced GABAAR-mediated currents in a recombinant system, in cultured hippocampal neurons, and in brain, with no effect on glycine or AMPA receptor-mediated currents. Conversely, knockdown of Clptm1 increased phasic and tonic inhibitory transmission with no effect on excitatory synaptic transmission. Furthermore, altering the expression level of Clptm1 mimicked activity-induced inhibitory synaptic scaling. Thus, in complement to other GABAAR-associated proteins that promote receptor surface expression, Clptm1 limits GABAAR forward trafficking and regulates inhibitory homeostatic plasticity.
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Affiliation(s)
- Yuan Ge
- Djavad Mowafaghian Centre for Brain Health and Department of Psychiatry, University of British Columbia, Vancouver, BC V6T 2B5, Canada
| | - Yunhee Kang
- Djavad Mowafaghian Centre for Brain Health and Department of Psychiatry, University of British Columbia, Vancouver, BC V6T 2B5, Canada
| | - Robert M Cassidy
- Djavad Mowafaghian Centre for Brain Health and Department of Psychiatry, University of British Columbia, Vancouver, BC V6T 2B5, Canada
| | - Kyung-Mee Moon
- Department of Biochemistry and Molecular Biology and Michael Smith Laboratories, University of British Columbia, Vancouver, BC V6T 1Z3, Canada
| | - Renate Lewis
- Department of Anatomy and Neurobiology, Washington University, St. Louis, MO 63110, USA
| | - Rachel O L Wong
- Department of Biological Structure, University of Washington, Seattle, WA 98195, USA
| | - Leonard J Foster
- Department of Biochemistry and Molecular Biology and Michael Smith Laboratories, University of British Columbia, Vancouver, BC V6T 1Z3, Canada
| | - Ann Marie Craig
- Djavad Mowafaghian Centre for Brain Health and Department of Psychiatry, University of British Columbia, Vancouver, BC V6T 2B5, Canada.
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13
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Wu XH, Song JJ, Faull RLM, Waldvogel HJ. GABAAand GABABreceptor subunit localization on neurochemically identified neurons of the human subthalamic nucleus. J Comp Neurol 2017; 526:803-823. [DOI: 10.1002/cne.24368] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2017] [Revised: 11/12/2017] [Accepted: 11/14/2017] [Indexed: 12/20/2022]
Affiliation(s)
- Xi Hua Wu
- Centre for Brain Research and Department of Anatomy and Medical Imaging, Faculty of Medical and Health Sciences; The University of Auckland; Auckland New Zealand
| | - Jennifer Junru Song
- Centre for Brain Research and Department of Anatomy and Medical Imaging, Faculty of Medical and Health Sciences; The University of Auckland; Auckland New Zealand
| | - Richard Lewis Maxwell Faull
- Centre for Brain Research and Department of Anatomy and Medical Imaging, Faculty of Medical and Health Sciences; The University of Auckland; Auckland New Zealand
| | - Henry John Waldvogel
- Centre for Brain Research and Department of Anatomy and Medical Imaging, Faculty of Medical and Health Sciences; The University of Auckland; Auckland New Zealand
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14
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Optican LM, Pretegiani E. A GABAergic Dysfunction in the Olivary-Cerebellar-Brainstem Network May Cause Eye Oscillations and Body Tremor. II. Model Simulations of Saccadic Eye Oscillations. Front Neurol 2017; 8:372. [PMID: 28824529 PMCID: PMC5543285 DOI: 10.3389/fneur.2017.00372] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2017] [Accepted: 07/17/2017] [Indexed: 01/15/2023] Open
Abstract
Eye and body oscillations are shared features of several neurological diseases, yet their pathophysiology remains unclear. Recently, we published a report on two tennis players with a novel presentation of eye and body oscillations following self-administration of performance-enhancing substances. Opsoclonus/flutter and limb tremor were diagnosed in both patients. Common causes of opsoclonus/flutter were excluded. High-resolution eye movement recordings from one patient showed novel spindle-shaped, asymmetric saccadic oscillations (at ~3.6 Hz) and ocular tremor (~40-60 Hz). Based on these findings, we proposed that the oscillations are the result of increased GABAA receptor sensitivity in a circuit involving the cerebellum (vermis and fastigial nuclei), the inferior olives, and the brainstem saccade premotor neurons (excitatory and inhibitory burst neurons, and omnipause neurons). We present a mathematical model of the saccadic system, showing that the proposed dysfunction in the network can reproduce the types of saccadic oscillations seen in these patients.
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Affiliation(s)
- Lance M. Optican
- Laboratory of Sensorimotor Research, IRP, National Eye Institute, National Institutes of Health, Bethesda, MD, United States
| | - Elena Pretegiani
- Laboratory of Sensorimotor Research, IRP, National Eye Institute, National Institutes of Health, Bethesda, MD, United States
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15
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Loss of Neuroligin3 specifically downregulates retinal GABAAα2 receptors without abolishing direction selectivity. PLoS One 2017; 12:e0181011. [PMID: 28708891 PMCID: PMC5510863 DOI: 10.1371/journal.pone.0181011] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2017] [Accepted: 06/23/2017] [Indexed: 11/19/2022] Open
Abstract
The postsynaptic adhesion proteins Neuroligins (NLs) are essential for proper synapse function, and their alterations are associated with a variety of neurodevelopmental disorders. It is increasingly clear that each NL isoform occupies specific subsets of synapses and is able to regulate the function of discrete networks. Studies of NL2 and NL4 in the retina in particular have contributed towards uncovering their role in inhibitory synapse function. In this study we show that NL3 is also predominantly expressed at inhibitory postsynapses in the retinal inner plexiform layer (IPL), where it colocalizes with both GABAA- and glycinergic receptor clusters in a 3:2 ratio. In the NL3 deletion-mutant (knockout or KO) mouse, we uncovered a dramatic reduction of the number of GABAAα2-subunit containing GABAA receptor clusters at the IPL. Retinal activity was thereafter assessed in KO and wild-type (WT) littermates by multi-electrode-array recordings of the output cells of retina, the retinal ganglion cells (RGCs). RGCs in the NL3 KO showed reduced spontaneous activity and an altered response to white noise stimulation. Moreover, upon application of light flashes, the proportion of cells firing at light offset (OFF RGCs) was significantly lower in the NL3 KO compared to WT littermates, whereas the relative number of cells firing at light onset (ON RGCs) increased. Interestingly, although GABAAα2-bearing receptors have been related to direction-selective circuits of the retina, features of direction selective-retinal ganglion cells recorded remained unperturbed in the NL3 KO. Together our data underscore the importance of NL3 for the integrity of specific GABAAergic retinal circuits and identifies NL3 as an important regulator of retinal activity.
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16
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Waldvogel H, Munkle M, van Roon-Mom W, Mohler H, Faull R. The immunohistochemical distribution of the GABA A receptor α 1 , α 2 , α 3 , β 2/3 and γ 2 subunits in the human thalamus. J Chem Neuroanat 2017; 82:39-55. [DOI: 10.1016/j.jchemneu.2017.04.006] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2016] [Revised: 03/31/2017] [Accepted: 04/19/2017] [Indexed: 11/24/2022]
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17
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Lai F, Fagernes CE, Jutfelt F, Nilsson GE. Expression of genes involved in brain GABAergic neurotransmission in three-spined stickleback exposed to near-future CO 2. CONSERVATION PHYSIOLOGY 2016; 4:cow068. [PMID: 28066553 PMCID: PMC5196030 DOI: 10.1093/conphys/cow068] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/05/2016] [Revised: 11/02/2016] [Accepted: 11/16/2016] [Indexed: 05/28/2023]
Abstract
Change in the activity of the main inhibitory receptor, GABAA, has been suggested to be a general mechanism behind the behavioural alterations reported in ocean acidification studies on fish. It has been proposed that regulatory acid-base mechanisms in response to high CO2 alter the neuronal Cl- and HCO3- gradients that are important for GABAA receptor function. Here, we report a comprehensive analysis of gene expression of GABAA receptor subunits and of genes involved in GABAergic transmission in the brain of fish exposed to near-future CO2. Altogether, 56 mRNA transcripts were quantified in brains of three-spined stickleback (Gasterosteus aculeatus) kept in control pCO2 (333 ± 30 μatm CO2) or at high pCO2 levels (991 ± 57 μatm) for 43 days. The gene expression analysis included GABAA receptor subunits (α1-6, β1-3, γ1-3, δ, π and ρ1-3), enzymes and transporters involved in GABA metabolism (GAD1-2, GABAT and GAT1-3), GABAA receptor-associated proteins (GABARAP and GABARAPL), ion cotransporters (KCC1-4, NKCC1, ClC21-3, AE3 and NDAE) and carbonic anhydrase (CAII). Exposure to high CO2 had only minor effects on the expression of genes involved in GABAergic neurotransmission. There were significant increases in the mRNA levels of α family subunits of the GABAA receptor, with a more pronounced expression of α12, α3, α4 and α6b. No changes were detected in the expression of other GABAA subunits or in genes related to receptor turnover, GABA metabolism or ion transport. Although the minor changes seen for mRNA levels might reflect compensatory mechanisms in the high-CO2 conditions, these were apparently insufficient to restore normal neural function, because the behavioural changes persisted within the time frame studied.
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Affiliation(s)
- Floriana Lai
- Section for Physiology and Cell Biology, Department of Biosciences, University of Oslo, Norway
| | - Cathrine E Fagernes
- Section for Physiology and Cell Biology, Department of Biosciences, University of Oslo, Norway
| | - Fredrik Jutfelt
- Department of Biology, Norwegian University of Science and Technology, Trondheim, Norway
| | - Göran E Nilsson
- Section for Physiology and Cell Biology, Department of Biosciences, University of Oslo, Norway
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18
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Chagraoui A, Skiba M, Thuillez C, Thibaut F. To what extent is it possible to dissociate the anxiolytic and sedative/hypnotic properties of GABAA receptors modulators? Prog Neuropsychopharmacol Biol Psychiatry 2016; 71:189-202. [PMID: 27495357 DOI: 10.1016/j.pnpbp.2016.08.001] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/13/2016] [Revised: 07/21/2016] [Accepted: 08/01/2016] [Indexed: 01/16/2023]
Abstract
The relatively common view indicates a possible dissociation between the anxiolytic and sedative/hypnotic properties of benzodiazepines (BZs). Indeed, GABAA receptor (GABAAR) subtypes have specific cerebral distribution in distinct neural circuits. Thus, GABAAR subtype-selective drugs may be expected to perform distinct functions. However, standard behavioral test assays provide limited direction towards highlighting new action mechanisms of ligands targeting GABAARs. Automated behavioral tests, lack sensitivity as some behavioral characteristics or subtle behavioral changes of drug effects or that are not considered in the overall analysis (Ohl et al., 2001) and observation-based analyses are not always performed. In addition, despite the use of genetically engineered mice, any possible dissociation between the anxiolytic and sedative properties of BZs remains controversial. Moreover, the involvement the different subtypes of GABAAR subtypes in the anxious behavior and the mechanism of action of anxiolytic agents remains unclear since there has been little success in the pharmacological investigations so far. This raises the question of the involvement of the different subunits in anxiolytic-like and/or sedative effects; and the actual implication of these subunits, particularly, α-subunits in the modulation of sedation and/or anxiety-related disorders. This present review was prompted by several conflicting studies on the degree of involvement of these subunits in anxiolytic-like and/or sedative effects. To this end, we explored the GABAergic system, particularly, the role of different subunits containing synaptic GABAARs. We report herein the targeting gene encoding the different subunits and their contribution in anxiolytic-like and/or sedative actions, as well as, the mechanism underlying tolerance to BZs.
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Affiliation(s)
- A Chagraoui
- Inserm U982, Laboratory of Neuronal and Neuroendocrine Differentiation and Communication, Institute for Research and Innovation in Biomedecine, Normandy University, France; Department of Medical Biochemistry, Rouen University Hospital, Rouen, France.
| | - M Skiba
- Inserm U982, Laboratory of Neuronal and Neuroendocrine Differentiation and Communication, Institute for Research and Innovation in Biomedecine, Normandy University, France
| | - C Thuillez
- Department of Pharmacology, Rouen University Hospital, Rouen, and INSERM U1096, Laboratory of New Pharmacological Targets for Endothelial Protection and Heart Failure, Institute for Research and Innovation in Biomedicine, Normandy University, France
| | - F Thibaut
- Department of Psychiatry, University Hospital Cochin (site Tarnier), University of Paris-Descartes and INSERM U 894 Laboratory of Psychiatry and Neurosciences, Paris, France
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19
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Tsai T, Yuan Y, Hajela RK, Philips SW, Atchison WD. Methylmercury induces an initial increase in GABA-evoked currents in Xenopus oocytes expressing α 1 and α 6 subunit-containing GABA A receptors. Neurotoxicology 2016; 60:161-170. [PMID: 27720918 DOI: 10.1016/j.neuro.2016.10.003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2015] [Revised: 09/26/2016] [Accepted: 10/05/2016] [Indexed: 11/29/2022]
Abstract
Early onset effects of methylmercury (MeHg) on recombinant α1β2γ2S or α6β2γ2S subunit-containing GABAA receptors were examined. These are two of the most prevalent receptor types found in cerebellum-a consistent target of MeHg-induced neurotoxicity. Heterologously expressed receptors were used in order to: (1) isolate receptor-mediated events from extraneous effects of MeHg due to stimulation of the receptor secondary to increased release of GABA seen with MeHg in neurons in situ and (2) limit the phenotypes of GABAA receptors present at one time. Initial changes in IGABA in Xenopus laevis oocytes expressing either α1β2γ2S or α6β2γ2S receptors were compared during continuous bath application of MeHg. A time-dependent increase in IGABA mediated by both receptor subtypes occurred following the first 25-30min of MeHg (5μM) exposure. In α6β2γ2S containing receptors, the MeHg-induced increase in IGABA was less pronounced compared to that mediated by α1β2γ2S containing receptors, although the pattern of effects was generally similar. Washing with MeHg-free solution reversed the increase in current amplitude. Application of bicuculline at the time of peak potentiation of IGABA rapidly and completely reversed the MeHg-induced currents. Therefore these MeHg-increased inward currents are mediated specifically by the two subtypes of GABAA receptors and appear to entail direct actions of MeHg on the receptor. However bicuculline did not affect stimulation by MeHg of oocyte endogenous Cl- -mediated current, which presumably results from increased [Ca2+]i. Thus, MeHg initially potentiates IGABA in oocytes expressing either α1β2γ2S or α6β2γ2S receptors prior to its more defined later effects, suggesting that MeHg may initially interact directly with GABAA receptors in a reversible manner to cause this potentiation.
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Affiliation(s)
- Tidao Tsai
- Department of Pharmacology and Toxicology, Michigan State University, East Lansing, MI 48824-1317, USA
| | - Yukun Yuan
- Department of Pharmacology and Toxicology, Michigan State University, East Lansing, MI 48824-1317, USA
| | - Ravindra K Hajela
- Department of Pharmacology and Toxicology, Michigan State University, East Lansing, MI 48824-1317, USA
| | - Shuan W Philips
- Department of Pharmacology and Toxicology, Michigan State University, East Lansing, MI 48824-1317, USA
| | - William D Atchison
- Department of Pharmacology and Toxicology, Michigan State University, East Lansing, MI 48824-1317, USA.
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20
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Li M, Hu L, Zhu F, Zhou Z, Tian J, Ai J. Hepatitis B virus X protein promotes renal epithelial-mesenchymal transition in human renal proximal tubule epithelial cells through the activation of NF-κB. Int J Mol Med 2016; 38:513-20. [PMID: 27314843 DOI: 10.3892/ijmm.2016.2637] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2015] [Accepted: 05/31/2016] [Indexed: 11/05/2022] Open
Abstract
Hepatitis B virus (HBV)-associated glomerulo-nephritis is the most common extra-hepatic disorder occurring with hepatitis B virus infection. In the present study, we hypothesized that HBV X protein (HBx) may play a critical role in renal interstitial fibrosis, as HBx has been shown to induce epithelial-mesenchymal transition (EMT) in renal cells. For this purpose, we successfully transfected HBx plasmid into human renal proximal tubule epithelial cells (HK-2 cells). We found that transfection with HBx plasmid significantly downregulated E-cadherin expression and upregulated α-smooth muscle actin, collagen I and fibronectin expression in a time- and concentration-dependent manner (at the lower concentrations and earlier time points). HBx also increased nuclear factor-κB (NF-κB) phosphorylation in a time- and concentration-dependent manner (again at the lower concentrations and earlier time points); however, it did not alter the phosphorylation of Smad2, Smad3, p38, phosphoinositide 3-kinase (PI3K) or extracellular signal-regulated kinase (ERK). Thus, the findings of this study demonstrate that HBx promotes EMT in renal HK-2 cells, and the potential underlying mechanisms may involve the activation of the NF-κB signaling pathway.
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Affiliation(s)
- Mei Li
- Division of Nephrology, Nanfang Hospital, Southern Medical University, Guangzhou, Guangdong 510515, P.R. China
| | - Liping Hu
- Division of Nephrology, Nanfang Hospital, Southern Medical University, Guangzhou, Guangdong 510515, P.R. China
| | - Fengxin Zhu
- Division of Nephrology, Nanfang Hospital, Southern Medical University, Guangzhou, Guangdong 510515, P.R. China
| | - Zhangmei Zhou
- Division of Nephrology, Nanfang Hospital, Southern Medical University, Guangzhou, Guangdong 510515, P.R. China
| | - Jianwei Tian
- Division of Nephrology, Nanfang Hospital, Southern Medical University, Guangzhou, Guangdong 510515, P.R. China
| | - Jun Ai
- Division of Nephrology, Nanfang Hospital, Southern Medical University, Guangzhou, Guangdong 510515, P.R. China
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Abstract
UNLABELLED Tonic GABA currents mediated by high-affinity extrasynaptic GABAA receptors, are increasingly recognized as important regulators of cell and neuronal network excitability. Dysfunctional GABAA receptor signaling that results in modified tonic GABA currents is associated with a number of neurological disorders. Consequently, developing compounds to selectively modulate the activity of extrasynaptic GABAA receptors underlying tonic inhibition is likely to prove therapeutically useful. Here, we examine the GABAA receptor subtype selectivity of the weak partial agonist, 5-(4-piperidyl)isoxazol-3-ol (4-PIOL), as a potential mechanism for modulating extrasynaptic GABAA receptor-mediated tonic currents. By using recombinant GABAA receptors expressed in HEK293 cells, and native GABAA receptors of cerebellar granule cells, hippocampal neurons, and thalamic relay neurons, 4-PIOL evidently displayed differential agonist and antagonist-type profiles, depending on the extrasynaptic GABAA receptor isoforms targeted. For neurons, this resulted in differential modulation of GABA tonic currents, depending on the cell type studied, their respective GABAA receptor subunit compositions, and critically, on the ambient GABA levels. Unexpectedly, 4-PIOL revealed a significant population of relatively low-affinity γ2 subunit-containing GABAA receptors in the thalamus, which can contribute to tonic inhibition under specific conditions when GABA levels are raised. Together, these data indicate that partial agonists, such as 4-PIOL, may be useful for modulating GABAA receptor-mediated tonic currents, but the direction and extent of this modulation is strongly dependent on relative expression levels of different extrasynaptic GABAA receptor subtypes, and on the ambient GABA levels. SIGNIFICANCE STATEMENT A background level of inhibition (tonic) is important in the brain for controlling neuronal excitability. Increased levels of tonic inhibition are associated with some neurological disorders but there are no specific ligands capable of selectively reducing tonic inhibition. Here we explore the use of a GABA partial agonist as a selective chemical tool in three different brain regions. We discover that the activity of a partial agonist is heavily dependent upon the GABAA receptor subunit composition underpinning tonic inhibition, and on the ambient levels of GABA in the brain.
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Curtice KJ, Leavitt LS, Chase K, Raghuraman S, Horvath MP, Olivera BM, Teichert RW. Classifying neuronal subclasses of the cerebellum through constellation pharmacology. J Neurophysiol 2015; 115:1031-42. [PMID: 26581874 DOI: 10.1152/jn.00894.2015] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2015] [Accepted: 11/12/2015] [Indexed: 11/22/2022] Open
Abstract
A pressing need in neurobiology is the comprehensive identification and characterization of neuronal subclasses within the mammalian nervous system. To this end, we used constellation pharmacology as a method to interrogate the neuronal and glial subclasses of the mouse cerebellum individually and simultaneously. We then evaluated the data obtained from constellation-pharmacology experiments by cluster analysis to classify cells into neuronal and glial subclasses, based on their functional expression of glutamate, acetylcholine, and GABA receptors, among other ion channels. Conantokin peptides were used to identify N-methyl-d-aspartate (NMDA) receptor subtypes, which revealed that neurons of the young mouse cerebellum expressed NR2A and NR2B NMDA receptor subunits. Additional pharmacological tools disclosed differential expression of α-amino-3-hydroxy-5-methyl-4-isoxazloepropionic, nicotinic acetylcholine, and muscarinic acetylcholine receptors in different neuronal and glial subclasses. Certain cell subclasses correlated with known attributes of granule cells, and we combined constellation pharmacology with genetically labeled neurons to identify and characterize Purkinje cells. This study illustrates the utility of applying constellation pharmacology to classify neuronal and glial subclasses in specific anatomical regions of the brain.
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Affiliation(s)
- Kigen J Curtice
- Department of Biology, University of Utah, Salt Lake City, Utah
| | - Lee S Leavitt
- Department of Biology, University of Utah, Salt Lake City, Utah
| | - Kevin Chase
- Department of Biology, University of Utah, Salt Lake City, Utah
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23
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Álvaro-Bartolomé M, García-Sevilla JA. The neuroplastic index p-FADD/FADD and phosphoprotein PEA-15, interacting at GABAA receptor, are upregulated in brain cortex during midazolam-induced hypnosis in mice. Eur Neuropsychopharmacol 2015; 25:2131-44. [PMID: 26282360 DOI: 10.1016/j.euroneuro.2015.07.019] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/25/2014] [Revised: 07/23/2015] [Accepted: 07/24/2015] [Indexed: 12/22/2022]
Abstract
Fas-associated death domain (FADD) adaptor is involved in the signaling of metabotropic G protein-coupled receptors, whose agonists stimulate its phosphoryaltion (p) increasing p-FADD/FADD ratio in brain. Whether FADD might also participate in the activation of dissimilar receptors such as the ligand-gated ion channels is not known. This study investigated the role of FADD and phosphoprotein-enriched in astrocytes of 15 kDa (PEA-15, a FADD partner) in the activation of γ-aminobutyric acid-A (GABAA) receptor, which mediates the hypnotic effect of midazolam. The main findings revealed that during the time course of midazolam (60 mg/kg)-induced hypnosis in mice (about 2 h) p-FADD (and p-FADD/FADD ratio) as well as p-PEA (and its phosphorylating Akt1 kinase) were markedly increased (36-80%) in brain cortex, and these effects were partially (only p-FADD) or fully prevented by flumazenil (a neutral allosteric ligand) and FG 7142 (a partial negative allosteric ligand) acting at GABAA receptors. The upregulation of cortical p-FADD/FADD was exclusively observed in the nucleus (up to 2.8-fold), where the transciption factor NF-κB was also increased (up to 46%), and that of p-PEA/p-Akt1 only in the cytosol (up to 53%), suggesting that p-FADD/p-PEA/p-Akt1 are involved in sleep-induced neuroplasticity. Repeated treatment with midazolam (60 mg/kg, 4 days) induced behavioral (prolonged sleep latency and reduced sleeping time) and neurochemical (reduced p-FADD/p-PEA contents) tolerance. These findings indicated that p-FADD/p-PEA are novel molecules in GABAA receptor signaling and that cortical p-PEA and p-FADD, working in tandem, are involved in the complex molecular processes leading to the hypnotic effect of midazolam in mice.
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Affiliation(s)
- María Álvaro-Bartolomé
- Laboratorio de Neurofarmacología, IUNICS-IdISPa, Universitat de les Illes Balears, Palma de Mallorca Spain; Redes Temáticas de Investigación Cooperativa en Salud-Red de Trastornos Adictivos (RETICS-RTA), ISCIII, Madrid, Spain
| | - Jesús A García-Sevilla
- Laboratorio de Neurofarmacología, IUNICS-IdISPa, Universitat de les Illes Balears, Palma de Mallorca Spain; Redes Temáticas de Investigación Cooperativa en Salud-Red de Trastornos Adictivos (RETICS-RTA), ISCIII, Madrid, Spain.
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Kim J, Takayama C, Park C, Ahn M, Moon C, Shin T. Immunohistochemical localization of GABAergic key molecules in the main olfactory bulb of the Korean roe deer, Capreolus pygargus. Acta Histochem 2015; 117:642-8. [PMID: 26115600 DOI: 10.1016/j.acthis.2015.06.006] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2014] [Revised: 05/14/2015] [Accepted: 06/10/2015] [Indexed: 10/23/2022]
Abstract
Gamma-amino butyric acid (GABA) negatively regulates the excitatory activity of neurons and is a predominant neurotransmitter in the nervous system. The olfactory bulb, the main center in the olfactory system, is modulated by inhibitory interneurons that use GABA as their main neurotransmitter. The present study aimed to evaluate GABAergic transmission in the main olfactory bulb (MOB) of the Korean roe deer (Capreolus pygargus) by examining the immunohistochemical localization of GABAergic key molecules, including glutamic acid decarboxylase (GAD), vesicular GABA transporter (VGAT), GABA transporters (GATs; GAT-1 and GAT-3), and potassium sodium chloride co-transporter 2 (KCC2). GAD, VGAT, and KCC2 were expressed in the glomerular layer (GL), external plexiform layer (ePL), mitral cell layer (ML), and granule cell layer (GrL). Intense GAT-1 expression was observed in the GL; GAT-1 expression was discernible in the ePL, ML, and GrL. However, intense GAT-3 expression was extensively observed in all layers of the MOB. These results suggest that substantial GABAergic synapses are present in the GL, ePL, ML, and GrL. Furthermore, the released GABA may be removed by GAT-1 and GAT-3 in the GL, and the majority of GABA, which is present in the ePL to GrL, may undergo reuptake by GAT-3. This is the first morphological and descriptive study of GABAergic transmission in the MOB of Korean roe deer.
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Affiliation(s)
- Jeongtae Kim
- Department of Molecular Anatomy, Faculty of Medicine, University of the Ryukyus, Uehara 207, Nishihara, Okinawa 903 0215, Japan
| | - Chitoshi Takayama
- Department of Molecular Anatomy, Faculty of Medicine, University of the Ryukyus, Uehara 207, Nishihara, Okinawa 903 0215, Japan
| | - Changnam Park
- Department of Veterinary Anatomy, College of Veterinary Medicine, Jeju National University, Jeju 690 756, Republic of Korea
| | - Meejung Ahn
- School of Medicine, Jeju National University, Jeju 690 756, Republic of Korea
| | - Changjong Moon
- Department of Veterinary Anatomy, College of Veterinary Medicine, Chonnam National University, 300 Yongbong-Dong, Buk-Gu, Gwangju 500 757, Republic of Korea.
| | - Taekyun Shin
- Department of Veterinary Anatomy, College of Veterinary Medicine, Jeju National University, Jeju 690 756, Republic of Korea.
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Ai J, Nie J, He J, Guo Q, Li M, Lei Y, Liu Y, Zhou Z, Zhu F, Liang M, Cheng Y, Hou FF. GQ5 Hinders Renal Fibrosis in Obstructive Nephropathy by Selectively Inhibiting TGF-β-Induced Smad3 Phosphorylation. J Am Soc Nephrol 2015; 26:1827-38. [PMID: 25392233 PMCID: PMC4520163 DOI: 10.1681/asn.2014040363] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2014] [Accepted: 09/29/2014] [Indexed: 11/03/2022] Open
Abstract
TGF-β1, via Smad-dependent or Smad-independent signaling, has a central role in the pathogenesis of renal fibrosis. This pathway has been recognized as a potential target for antifibrotic therapy. Here, we identified GQ5, a small molecular phenolic compound isolated from the dried resin of Toxicodendron vernicifluum, as a potent and selective inhibitor of TGF-β1-induced Smad3 phosphorylation. In TGF-β1-stimulated renal tubular epithelial cells and interstitial fibroblast cells, GQ5 inhibited the interaction of Smad3 with TGF-β type I receptor (TβRI) by blocking binding of Smad3 to SARA, suppressed subsequent phosphorylation of Smad3, reduced nuclear translocation of Smad2, Smad3, and Smad4, and downregulated the transcription of major fibrotic genes such as α-smooth muscle actin (α-SMA), collagen I, and fibronectin. Notably, intraperitoneal administration of GQ5 in rats immediately after unilateral ureteral obstruction (UUO) selectively inhibited Smad3 phosphorylation in UUO kidneys, suppressed renal expression of α-SMA, collagen I, and fibronectin, and resulted in impressive renal protection after obstructive injury. Late administration of GQ5 also effectively attenuated fibrotic lesions in obstructive nephropathy. In conclusion, our results suggest that GQ5 hinders renal fibrosis in rats by selective inhibition of TGF-β1-induced Smad3 phosphorylation.
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Affiliation(s)
- Jun Ai
- State Key Laboratory of Organ Failure Research, National Clinical Research Center for Kidney Disease, and Division of Nephrology, Nanfang Hospital, Southern Medical University, Guangzhou, China; and
| | - Jing Nie
- State Key Laboratory of Organ Failure Research, National Clinical Research Center for Kidney Disease, and Division of Nephrology, Nanfang Hospital, Southern Medical University, Guangzhou, China; and
| | - Jiangbo He
- State Key Laboratory of Phytochemistry and Plant Resources in West China, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, China
| | - Qin Guo
- State Key Laboratory of Organ Failure Research, National Clinical Research Center for Kidney Disease, and Division of Nephrology, Nanfang Hospital, Southern Medical University, Guangzhou, China; and
| | - Mei Li
- State Key Laboratory of Organ Failure Research, National Clinical Research Center for Kidney Disease, and Division of Nephrology, Nanfang Hospital, Southern Medical University, Guangzhou, China; and
| | - Ying Lei
- State Key Laboratory of Organ Failure Research, National Clinical Research Center for Kidney Disease, and Division of Nephrology, Nanfang Hospital, Southern Medical University, Guangzhou, China; and
| | - Youhua Liu
- State Key Laboratory of Organ Failure Research, National Clinical Research Center for Kidney Disease, and Division of Nephrology, Nanfang Hospital, Southern Medical University, Guangzhou, China; and
| | - Zhanmei Zhou
- State Key Laboratory of Organ Failure Research, National Clinical Research Center for Kidney Disease, and Division of Nephrology, Nanfang Hospital, Southern Medical University, Guangzhou, China; and
| | - Fengxin Zhu
- State Key Laboratory of Organ Failure Research, National Clinical Research Center for Kidney Disease, and Division of Nephrology, Nanfang Hospital, Southern Medical University, Guangzhou, China; and
| | - Min Liang
- State Key Laboratory of Organ Failure Research, National Clinical Research Center for Kidney Disease, and Division of Nephrology, Nanfang Hospital, Southern Medical University, Guangzhou, China; and
| | - Yongxian Cheng
- State Key Laboratory of Phytochemistry and Plant Resources in West China, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, China
| | - Fan Fan Hou
- State Key Laboratory of Organ Failure Research, National Clinical Research Center for Kidney Disease, and Division of Nephrology, Nanfang Hospital, Southern Medical University, Guangzhou, China; and
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He Q, Duguid I, Clark B, Panzanelli P, Patel B, Thomas P, Fritschy JM, Smart TG. Interneuron- and GABA(A) receptor-specific inhibitory synaptic plasticity in cerebellar Purkinje cells. Nat Commun 2015; 6:7364. [PMID: 26179122 PMCID: PMC4518301 DOI: 10.1038/ncomms8364] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2014] [Accepted: 05/01/2015] [Indexed: 01/16/2023] Open
Abstract
Inhibitory synaptic plasticity is important for shaping both neuronal excitability and network activity. Here we investigate the input and GABA(A) receptor subunit specificity of inhibitory synaptic plasticity by studying cerebellar interneuron-Purkinje cell (PC) synapses. Depolarizing PCs initiated a long-lasting increase in GABA-mediated synaptic currents. By stimulating individual interneurons, this plasticity was observed at somatodendritic basket cell synapses, but not at distal dendritic stellate cell synapses. Basket cell synapses predominantly express β2-subunit-containing GABA(A) receptors; deletion of the β2-subunit ablates this plasticity, demonstrating its reliance on GABA(A) receptor subunit composition. The increase in synaptic currents is dependent upon an increase in newly synthesized cell surface synaptic GABA(A) receptors and is abolished by preventing CaMKII phosphorylation of GABA(A) receptors. Our results reveal a novel GABA(A) receptor subunit- and input-specific form of inhibitory synaptic plasticity that regulates the temporal firing pattern of the principal output cells of the cerebellum.
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Affiliation(s)
- Qionger He
- Department of Neuroscience, Physiology and Pharmacology, UCL, Gower Street, London WC1E 6BT, UK
| | - Ian Duguid
- Department of Neuroscience, Physiology and Pharmacology, UCL, Gower Street, London WC1E 6BT, UK
| | - Beverley Clark
- Wolfson Institute for Biomedical Research, UCL, Gower Street, London WC1E 6BT, UK
| | - Patrizia Panzanelli
- Department of Neuroscience Rita Levi Montalcini, University of Turin, 15-10126 Turin, Italy
| | - Bijal Patel
- Department of Neuroscience, Physiology and Pharmacology, UCL, Gower Street, London WC1E 6BT, UK
| | - Philip Thomas
- Department of Neuroscience, Physiology and Pharmacology, UCL, Gower Street, London WC1E 6BT, UK
| | - Jean-Marc Fritschy
- Institute of Pharmacology, University of Zurich, Winterthurestrasse 190, Zurich 8057, Switzerland
| | - Trevor G Smart
- Department of Neuroscience, Physiology and Pharmacology, UCL, Gower Street, London WC1E 6BT, UK
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Bienvenu TCM, Busti D, Micklem BR, Mansouri M, Magill PJ, Ferraguti F, Capogna M. Large intercalated neurons of amygdala relay noxious sensory information. J Neurosci 2015; 35:2044-57. [PMID: 25653362 PMCID: PMC4315833 DOI: 10.1523/jneurosci.1323-14.2015] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2014] [Revised: 11/07/2014] [Accepted: 11/13/2014] [Indexed: 01/03/2023] Open
Abstract
Various GABAergic neuron types of the amygdala cooperate to control principal cell firing during fear-related and other behaviors, and understanding their specialized roles is important. Among GABAergic neurons, the so-called intercalated cells (ITCcs) are critically involved in the expression and extinction of fear memory. Tightly clustered small-sized spiny neurons constitute the majority of ITCcs, but they are surrounded by sparse, larger neurons (L-ITCcs) for which very little information is known. We report here a detailed neurochemical, structural and physiological characterization of rat L-ITCcs, as identified with juxtacellular recording/labeling in vivo. We supplement these data with anatomical and neurochemical analyses of nonrecorded L-ITCcs. We demonstrate that L-ITCcs are GABAergic, and strongly express metabotropic glutamate receptor 1α and GABAA receptor α1 subunit, together with moderate levels of parvalbumin. Furthermore, L-ITCcs are innervated by fibers enriched with metabotropic glutamate receptors 7a and/or 8a. In contrast to small-sized spiny ITCcs, L-ITCcs possess thick, aspiny dendrites, have highly branched, long-range axonal projections, and innervate interneurons in the basolateral amygdaloid complex. The axons of L-ITCcs also project to distant brain areas, such as the perirhinal, entorhinal, and endopiriform cortices. In vivo recorded L-ITCcs are strongly activated by noxious stimuli, such as hindpaw pinches or electrical footshocks. Consistent with this, we observed synaptic contacts on L-ITCc dendrites from nociceptive intralaminar thalamic nuclei. We propose that, during salient sensory stimulation, L-ITCcs disinhibit local and distant principal neurons, acting as "hub cells," to orchestrate the activity of a distributed network.
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Affiliation(s)
- Thomas C M Bienvenu
- Medical Research Council Anatomical Neuropharmacology Unit, Department of Pharmacology, University of Oxford, Oxford OX1 3TH, United Kingdom, and
| | - Daniela Busti
- Department of Pharmacology, Medical University of Innsbruck, 6020 Innsbruck, Austria
| | - Benjamin R Micklem
- Medical Research Council Anatomical Neuropharmacology Unit, Department of Pharmacology, University of Oxford, Oxford OX1 3TH, United Kingdom, and
| | - Mahnaz Mansouri
- Department of Pharmacology, Medical University of Innsbruck, 6020 Innsbruck, Austria
| | - Peter J Magill
- Medical Research Council Anatomical Neuropharmacology Unit, Department of Pharmacology, University of Oxford, Oxford OX1 3TH, United Kingdom, and
| | - Francesco Ferraguti
- Department of Pharmacology, Medical University of Innsbruck, 6020 Innsbruck, Austria
| | - Marco Capogna
- Medical Research Council Anatomical Neuropharmacology Unit, Department of Pharmacology, University of Oxford, Oxford OX1 3TH, United Kingdom, and
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Waldvogel H, Faull R. The Diversity of GABAA Receptor Subunit Distribution in the Normal and Huntington's Disease Human Brain1. DIVERSITY AND FUNCTIONS OF GABA RECEPTORS: A TRIBUTE TO HANNS MÖHLER, PART B 2015; 73:223-64. [DOI: 10.1016/bs.apha.2014.11.010] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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Fritschy JM. Significance of GABAA Receptor Heterogeneity. DIVERSITY AND FUNCTIONS OF GABA RECEPTORS: A TRIBUTE TO HANNS MÖHLER, PART B 2015; 73:13-39. [DOI: 10.1016/bs.apha.2014.11.006] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
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Möhler H. The legacy of the benzodiazepine receptor: from flumazenil to enhancing cognition in Down syndrome and social interaction in autism. ADVANCES IN PHARMACOLOGY (SAN DIEGO, CALIF.) 2014; 72:1-36. [PMID: 25600365 DOI: 10.1016/bs.apha.2014.10.008] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
The study of the psychopharmacology of benzodiazepines continues to provide new insights into diverse brain functions related to vigilance, anxiety, mood, epileptiform activity, schizophrenia, cognitive performance, and autism-related social behavior. In this endeavor, the discovery of the benzodiazepine receptor was a key event, as it supplied the primary benzodiazepine drug-target site, provided the molecular link to the allosteric modulation of GABAA receptors and, following the recognition of GABAA receptor subtypes, furnished the platform for future, more selective drug actions. This review has two parts. In a retrospective first part, it acknowledges the contributions to the field made by my collaborators over the years, initially at Hoffmann-La Roche in Basle and later, in academia, at the University and the ETH of Zurich. In the second part, the new frontier of GABA pharmacology, targeting GABAA receptor subtypes, is reviewed with special focus on nonsedative anxiolytics, antidepressants, analgesics, as well as enhancers of cognition in Down syndrome and attenuators of symptoms of autism spectrum disorders. It is encouraging that a clinical trial has been initiated with a partial inverse agonist acting on α5 GABAA receptors in an attempt to alleviate the cognitive deficits in Down syndrome.
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Affiliation(s)
- Hanns Möhler
- Institute of Pharmacology and Toxicology, University of Zurich, Zurich, Switzerland; Department of Chemistry and Applied Biosciences, Federal Institute of Technology (ETH), Zurich, Switzerland.
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31
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Crestani F, Rudolph U. Behavioral functions of GABAA receptor subtypes--the Zurich experience. ADVANCES IN PHARMACOLOGY (SAN DIEGO, CALIF.) 2014; 72:37-51. [PMID: 25600366 DOI: 10.1016/bs.apha.2014.10.001] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
GABAA receptors are the major inhibitory neurotransmitter receptors in the brain. They are heteropentamers that are typically classified according to their α subunits. By rendering each of the benzodiazepine-sensitive α subunits (α1, α2, α3, and α5) insensitive to modulation by classical benzodiazepines by His to Arg point mutations in knock-in mice, we were able to identify behavioral functions mediated by different GABAA receptor subtypes, which led to the development of novel therapeutic strategies. In this chapter, we provide a largely chronological overview on behavioral studies on GABAA receptor mutant mice at the Institute of Pharmacology and Toxicology at the University of Zurich.
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Affiliation(s)
- Florence Crestani
- Institute of Pharmacology and Toxicology, University of Zurich, Zurich, Switzerland
| | - Uwe Rudolph
- Laboratory of Genetic Neuropharmacology, McLean Hospital, Belmont, Massachusetts, USA; Department of Psychiatry, Harvard Medical School, Boston, Massachusetts, USA.
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32
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Martin CBP, Gassmann M, Chevarin C, Hamon M, Rudolph U, Bettler B, Lanfumey L, Mongeau R. Effect of genetic and pharmacological blockade of GABA receptors on the 5-HT2C receptor function during stress. J Neurochem 2014; 131:566-72. [PMID: 25113583 DOI: 10.1111/jnc.12929] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2014] [Revised: 07/27/2014] [Accepted: 08/08/2014] [Indexed: 11/28/2022]
Abstract
Serotonin (5-HT)2C receptors play a role in psychoaffective disorders and often contribute to the antidepressant and anxiolytic effects of psychotropic drugs. During stress, activation of these receptors exerts a negative feedback on 5-HT release, probably by increasing the activity of GABAergic interneurons. However, to date, the GABA receptor types that mediate the 5-HT2C receptor-induced feedback inhibition are still unknown. To address this question, we assessed the inhibition of 5-HT turnover by a 5-HT2C receptor agonist (RO 60-0175) at the hippocampal level and under conditions of stress, after pharmacological or genetic inactivation of either GABA-A or GABA-B receptors in mice. Neither the GABA-B receptor antagonist phaclofen nor the specific genetic ablation of either GABA-B1a or GABA-B1b subunits altered the inhibitory effect of RO 60-0175, although 5-HT turnover was markedly decreased in GABA-B1a knock-out mice in both basal and stress conditions. In contrast, the 5-HT2C receptor-mediated inhibition of 5-HT turnover was reduced by the GABA-A receptor antagonist bicuculline. However, a significant effect of 5-HT2C receptor activation persisted in mutant mice deficient in the α3 subunit of GABA-A receptors. It can be inferred that non-α3 subunit-containing GABA-A receptors, but not GABA-B receptors, mediate the 5-HT2C -induced inhibition of stress-induced increase in hippocampal 5-HT turnover in mice.
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Affiliation(s)
- Cédric B P Martin
- Paris Descartes, University of Paris, Paris, France; UPMC, University of Paris, Paris, France; Inserm UMR S894, Centre de Psychiatrie et Neurosciences, Paris, France
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Liang CL, Marks GA. GABAA receptors are located in cholinergic terminals in the nucleus pontis oralis of the rat: Implications for REM sleep control. Brain Res 2014; 1543:58-64. [DOI: 10.1016/j.brainres.2013.10.019] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2013] [Revised: 10/02/2013] [Accepted: 10/10/2013] [Indexed: 10/26/2022]
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Iyer SV, Chandra D, Homanics GE. GABAA-R α4 subunits are required for the low dose locomotor stimulatory effect of alphaxalone, but not for several other behavioral responses to alphaxalone, etomidate or propofol. Neurochem Res 2013; 39:1048-56. [PMID: 24062179 DOI: 10.1007/s11064-013-1148-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2013] [Revised: 08/26/2013] [Accepted: 08/30/2013] [Indexed: 10/26/2022]
Abstract
γ-Aminobutyric acid type A receptors (GABAA-Rs) are considered to be the primary molecular targets of injectable anesthetics such as propofol, etomidate and the neurosteriod, alphaxalone. A number of studies have sought to understand the specific GABAA-R subtypes involved in the mechanism of action of these three drugs. Here, we investigated the role of α4-subunit containing GABAA-Rs in the neurobehavioral responses to these drugs. Drug responses in α4 subunit knockout (KO) mice were compared to wild type (WT) littermate controls. While etomidate and propofol are currently used as injectable anesthetics, alphaxalone belongs to the class of neurosteroid drugs having anesthetic effects. Low dose effects of etomidate and alphaxalone were studied using an open field assay. The moderate and high dose effects of all three anesthetics were measured using the rotarod and loss of righting reflex assays, respectively. The locomotor stimulatory effect of alphaxalone was reduced significantly in α4 KO mice compared to WT controls. Neither the low dose sedating effect of etomidate, nor the moderate/high dose effect of any of the drugs differed between genotypes. These results suggest that α4 subunit-containing GABAA-Rs are required for the low dose, locomotor stimulatory effect of alphaxalone but are not required for the sedating effect of etomidate or the moderate/high dose effects of etomidate, propofol or alphaxalone on motor ataxia and loss of righting reflex.
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Affiliation(s)
- Sangeetha V Iyer
- Department of Pharmacology and Chemical Biology, University of Pittsburgh, Pittsburgh, PA, USA
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Dieriks BV, Waldvogel HJ, Monzo HJ, Faull RLM, Curtis MA. GABA(A) receptor characterization and subunit localization in the human sub-ventricular zone. J Chem Neuroanat 2013; 52:58-68. [PMID: 23770130 DOI: 10.1016/j.jchemneu.2013.06.001] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2013] [Revised: 05/29/2013] [Accepted: 06/01/2013] [Indexed: 11/19/2022]
Abstract
It is now well established that the human brain continuously produces new stem cells until well into old age. One of these stem-cell rich areas in the human brain is the sub-ventricular zone (SVZ). The human SVZ is organized in four distinctive layers containing type A, B and C cells. To date, no studies have investigated the distribution of inhibitory neurotransmitters such as γ-aminobutyric acid (GABA) and their respective receptors on the different cell types in the human SVZ. GABA(A) receptors (GABA(A)R) are ubiquitously expressed, inhibitory heteropentameric chloride ion channels comprised of a variety of subunits that are targeted by many prescribed drugs. In this study we present detailed immunohistochemical data on the regional and cellular localization of α₁, α₂, α3, β₂,₃ and γ₂ subunits of GABA(A)R in the human SVZ. The results from our double and triple labeling studies demonstrate that the cell types and subunit composition throughout the SVZ is heterogeneous; the thickness of the SVZ and GABA(A)R α₂ and γ₂ expression is increased especially in the vicinity of large SVZ blood vessels. GABA(A)R γ₂ is the most specific to the SVZ and present on various cells that express, either glial fibrillary acidic protein (GFAPδ) or polysialic acid-neural cell adhesion molecule (PSA-NCAM) separately, or together in a respective ratio of 7:6:2. Proliferating (type C) cells in the SVZ express GAD65/67, GFAPδ and GABA(A)R β₂,₃ receptor subunits. Within the SVZ the majority of cells have an unexpected nuclear GABA(A)R β₂,₃ expression that is inversely proportional to that of PCNA (proliferating cell nuclear antigen marker), which is a very different pattern of expression compared with underlying caudate nucleus cells. Taken together our results provide a detailed description of the chemo-architecture of the adult human SVZ demonstrating the importance of GABA and GABA(A) receptors on the various cell types in the SVZ.
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Affiliation(s)
- Birger V Dieriks
- Department of Anatomy with Radiology and Centre for Brain Research, Faculty of Medical and Health Science, University of Auckland, Private Bag 92019, Auckland, New Zealand
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Bazyan AS, van Luijtelaar G. Neurochemical and behavioral features in genetic absence epilepsy and in acutely induced absence seizures. ISRN NEUROLOGY 2013; 2013:875834. [PMID: 23738145 PMCID: PMC3664506 DOI: 10.1155/2013/875834] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/21/2013] [Accepted: 02/06/2013] [Indexed: 02/08/2023]
Abstract
The absence epilepsy typical electroencephalographic pattern of sharp spikes and slow waves (SWDs) is considered to be due to an interaction of an initiation site in the cortex and a resonant circuit in the thalamus. The hyperpolarization-activated cyclic nucleotide-gated cationic I h pacemaker channels (HCN) play an important role in the enhanced cortical excitability. The role of thalamic HCN in SWD occurrence is less clear. Absence epilepsy in the WAG/Rij strain is accompanied by deficiency of the activity of dopaminergic system, which weakens the formation of an emotional positive state, causes depression-like symptoms, and counteracts learning and memory processes. It also enhances GABAA receptor activity in the striatum, globus pallidus, and reticular thalamic nucleus, causing a rise of SWD activity in the cortico-thalamo-cortical networks. One of the reasons for the occurrence of absences is that several genes coding of GABAA receptors are mutated. The question arises: what the role of DA receptors is. Two mechanisms that cause an infringement of the function of DA receptors in this genetic absence epilepsy model are proposed.
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Affiliation(s)
- A. S. Bazyan
- Institute of Higher Nervous Activity and Neurophysiology, Russian Academy of Science, Russian Federation, 5A Butlerov Street, Moscow 117485, Russia
| | - G. van Luijtelaar
- Biological Psychology, Donders Centre for Cognition, Donders Institute for Brain, Cognition and Behavior, Radboud University Nijmegen, P.O. Box 9104, 6500 HE Nijmegen, The Netherlands
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Makaron L, Moran CA, Namjoshi O, Rallapalli S, Cook JM, Rowlett JK. Cognition-impairing effects of benzodiazepine-type drugs: role of GABAA receptor subtypes in an executive function task in rhesus monkeys. Pharmacol Biochem Behav 2013; 104:62-8. [PMID: 23290931 DOI: 10.1016/j.pbb.2012.12.018] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/19/2012] [Revised: 11/19/2012] [Accepted: 12/22/2012] [Indexed: 10/27/2022]
Abstract
The present studies evaluated the role of α1 and α5 subunit-containing GABAA receptors (α1GABAA and α5GABAA receptors, respectively) in the ability of benzodiazepine (BZ)-type drugs to alter performance in the cognitive domain of executive function. Five adult female rhesus monkeys (ages of 9-17years old) were trained on the object retrieval with detours (ORD) task of executive function. For the ORD task, the monkeys were required to retrieve food items from a clear box with one open end that was rotated to different positions along with varying placements of food. When the non-selective BZ triazolam and the α1GABAA-preferring agonists zolpidem and zaleplon were evaluated in the ORD task, deficits in performance occurred at doses that did not increase the latency of monkeys to initiate responding and/or increase the percentage of reaches that were incorrect (i.e., reaches in which food was not obtained). Cognition-impairing effects of triazolam and zolpidem in ORD were blocked by the α1GABAA-preferring antagonist, βCCT, whereas the α5GABAA-preferring antagonist XLi-093 blocked the effects of triazolam but not zolpidem. While these findings suggest a role for both α1GABAA and α5GABAA receptor mechanisms, α1GABAA receptor mechanisms appear to be sufficient for impairments in executive function induced by BZ-type drugs.
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Affiliation(s)
- Leah Makaron
- Division of Neuroscience, New England Primate Research Center, Harvard Medical School, Box 9102, 1 Pine Hill Drive, Southborough, MA 01772, USA.
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Ion Channels. Mol Pharmacol 2012. [DOI: 10.1002/9781118451908.ch4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
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Blednov YA, Benavidez JM, Black M, Chandra D, Homanics GE, Rudolph U, Harris RA. Linking GABA(A) receptor subunits to alcohol-induced conditioned taste aversion and recovery from acute alcohol intoxication. Neuropharmacology 2012; 67:46-56. [PMID: 23147414 DOI: 10.1016/j.neuropharm.2012.10.016] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2012] [Revised: 10/12/2012] [Accepted: 10/28/2012] [Indexed: 10/27/2022]
Abstract
GABA type A receptors (GABA(A)-R) are important for ethanol actions and it is of interest to link individual subunits with specific ethanol behaviors. We studied null mutant mice for six different GABA(A)-R subunits (α1, α2, α3, α4, α5 and δ). Only mice lacking the α2 subunit showed reduction of conditioned taste aversion (CTA) to ethanol. These results are in agreement with data from knock-in mice with mutation of the ethanol-sensitive site in the α2-subunit (Blednov et al., 2011). All together, they indicate that aversive property of ethanol is dependent on ethanol action on α2-containing GABA(A)-R. Deletion of the α2-subunit led to faster recovery whereas absence of the α3-subunit slowed recovery from ethanol-induced incoordination (rotarod). Deletion of the other four subunits did not affect this behavior. Similar changes in this behavior for the α2 and α3 null mutants were found for flurazepam motor incoordination. However, no differences in recovery were found in motor-incoordinating effects of an α1-selective modulator (zolpidem) or an α4-selective agonist (gaboxadol). Therefore, recovery of rotarod incoordination is under control of two GABA(A)-R subunits: α2 and α3. For motor activity, α3 null mice demonstrated higher activation by ethanol (1 g/kg) whereas both α2 (-/-) and α3 (-/Y) knockout mice were less sensitive to ethanol-induced reduction of motor activity (1.5 g/kg). These studies demonstrate that the effects of ethanol at GABAergic synapses containing α2 subunit are important for specific behavioral effects of ethanol which may be relevant to the genetic linkage of the α2 subunit with human alcoholism.
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Affiliation(s)
- Y A Blednov
- Waggoner Center for Alcohol and Addiction Research, The University of Texas at Austin, 1 University Station, A4800, Austin, TX 78712, USA.
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40
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Clusters of secretagogin-expressing neurons in the aged human olfactory tract lack terminal differentiation. Proc Natl Acad Sci U S A 2012; 109:6259-64. [PMID: 22474393 DOI: 10.1073/pnas.1203843109] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
Expanding the repertoire of molecularly diverse neurons in the human nervous system is paramount to characterizing the neuronal networks that underpin sensory processing. Defining neuronal identities is particularly timely in the human olfactory system, whose structural differences from nonprimate macrosmatic species have recently gained momentum. Here, we identify clusters of bipolar neurons in a previously unknown outer "shell" domain of the human olfactory tract, which express secretagogin, a cytosolic Ca(2+) binding protein. These "shell" neurons are wired into the olfactory circuitry because they can receive mixed synaptic inputs. Unexpectedly, secretagogin is often coexpressed with polysialylated-neural cell adhesion molecule, β-III-tubulin, and calretinin, suggesting that these neurons represent a cell pool that might have escaped terminal differentiation into the olfactory circuitry. We hypothesized that secretagogin-containing "shell" cells may be eliminated from the olfactory axis under neurodegenerative conditions. Indeed, the density, but not the morphological or neurochemical integrity, of secretagogin-positive neurons selectively decreases in the olfactory tract in Alzheimer's disease. In conclusion, secretagogin identifies a previously undescribed cell pool whose cytoarchitectonic arrangements and synaptic connectivity are poised to modulate olfactory processing in humans.
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Antonucci F, Alpár A, Kacza J, Caleo M, Verderio C, Giani A, Martens H, Chaudhry FA, Allegra M, Grosche J, Michalski D, Erck C, Hoffmann A, Harkany T, Matteoli M, Härtig W. Cracking down on inhibition: selective removal of GABAergic interneurons from hippocampal networks. J Neurosci 2012; 32:1989-2001. [PMID: 22323713 PMCID: PMC3742881 DOI: 10.1523/jneurosci.2720-11.2012] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2011] [Revised: 12/07/2011] [Accepted: 12/14/2011] [Indexed: 12/12/2022] Open
Abstract
Inhibitory (GABAergic) interneurons entrain assemblies of excitatory principal neurons to orchestrate information processing in the hippocampus. Disrupting the dynamic recruitment as well as the temporally precise activity of interneurons in hippocampal circuitries can manifest in epileptiform seizures, and impact specific behavioral traits. Despite the importance of GABAergic interneurons during information encoding in the brain, experimental tools to selectively manipulate GABAergic neurotransmission are limited. Here, we report the selective elimination of GABAergic interneurons by a ribosome inactivation approach through delivery of saporin-conjugated anti-vesicular GABA transporter antibodies (SAVAs) in vitro as well as in the mouse and rat hippocampus in vivo. We demonstrate the selective loss of GABAergic--but not glutamatergic--synapses, reduced GABA release, and a shift in excitation/inhibition balance in mixed cultures of hippocampal neurons exposed to SAVAs. We also show the focal and indiscriminate loss of calbindin(+), calretinin(+), parvalbumin/system A transporter 1(+), somatostatin(+), vesicular glutamate transporter 3 (VGLUT3)/cholecystokinin/CB(1) cannabinoid receptor(+) and neuropeptide Y(+) local-circuit interneurons upon SAVA microlesions to the CA1 subfield of the rodent hippocampus, with interneuron debris phagocytosed by infiltrating microglia. SAVA microlesions did not affect VGLUT1(+) excitatory afferents. Yet SAVA-induced rearrangement of the hippocampal circuitry triggered network hyperexcitability associated with the progressive loss of CA1 pyramidal cells and the dispersion of dentate granule cells. Overall, our data identify SAVAs as an effective tool to eliminate GABAergic neurons from neuronal circuits underpinning high-order behaviors and cognition, and whose manipulation can recapitulate pathogenic cascades of epilepsy and other neuropsychiatric illnesses.
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Affiliation(s)
- Flavia Antonucci
- Department of Medical Pharmacology, CNR Institute of Neuroscience, Università di Milano and
- Fondazione Filarete, I-20129 Milan, Italy
| | - Alán Alpár
- Division of Molecular Neurobiology, Department of Medical Biochemistry & Biophysics, Karolinska Institutet, S-17177 Stockholm, Sweden
| | - Johannes Kacza
- Institute of Veterinary Anatomy, University of Leipzig, D-04103 Leipzig, Germany
| | - Matteo Caleo
- CNR Institute of Neuroscience, I-51600 Pisa, Italy
| | - Claudia Verderio
- Department of Medical Pharmacology, CNR Institute of Neuroscience, Università di Milano and
| | - Alice Giani
- Department of Medical Pharmacology, CNR Institute of Neuroscience, Università di Milano and
| | | | - Farrukh A. Chaudhry
- The Biotechnology Centre of Oslo & Centre for Molecular Biology and Neuroscience, University of Oslo, N-0317 Oslo, Norway
| | | | - Jens Grosche
- Paul Flechsig Institute for Brain Research, University of Leipzig, D-04109 Leipzig, Germany
| | - Dominik Michalski
- Department of Neurology, University of Leipzig, D-04103 Leipzig, Germany
| | | | - Anke Hoffmann
- Institute of Veterinary Anatomy, University of Leipzig, D-04103 Leipzig, Germany
| | - Tibor Harkany
- Division of Molecular Neurobiology, Department of Medical Biochemistry & Biophysics, Karolinska Institutet, S-17177 Stockholm, Sweden
- European Neuroscience Institute, University of Aberdeen, Aberdeen AB25 2ZD, United Kingdom, and
| | - Michela Matteoli
- Department of Medical Pharmacology, CNR Institute of Neuroscience, Università di Milano and
- Instituto Clinico Humanitas, IRCCS, Rozzano, I-20089 Milan, Italy
| | - Wolfgang Härtig
- Paul Flechsig Institute for Brain Research, University of Leipzig, D-04109 Leipzig, Germany
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Huang Y, Ko H, Cheung ZH, Yung KKL, Yao T, Wang JJ, Morozov A, Ke Y, Ip NY, Yung WH. Dual actions of brain-derived neurotrophic factor on GABAergic transmission in cerebellar Purkinje neurons. Exp Neurol 2012; 233:791-8. [PMID: 22178325 DOI: 10.1016/j.expneurol.2011.11.043] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2011] [Revised: 11/18/2011] [Accepted: 11/25/2011] [Indexed: 10/14/2022]
Abstract
The ability to regulate inhibitory synapses is a critical feature of the nervous system and a growing body of evidence indicates that brain-derived neurotrophic factor (BDNF) acutely modulates the efficacy of GABA synaptic transmission. Although the neuronal potassium-chloride cotransporter 2 (KCC2) has been implied in this BDNF-induced ionic plasticity, the reports about actions of BDNF on GABA signaling remain conflicting. Here we show dual effects of BDNF on GABAergic synaptic transmission in Purkinje neurons in rat cerebellar slices. BDNF decreased the amplitude of evoked outward IPSCs postsynaptically. It induced a depolarizing shift in the reversal potential (E(IPSC)), which reduced the driving force for outward IPSCs. However, in the absence of KCC2 activity, BDNF directly potentiated rather than inhibited GABA(A) receptor, which was reflected by an increase in the amplitude of outward IPSCs. This action of BDNF coincided with its effect in increasing the amplitude of inward IPSCs. Furthermore, an interaction between GABA(A) receptor and KCC2 was revealed by co-immunoprecipitation. The effects of BDNF on both GABA(A) receptor and KCC2 were dependent on TrkB and also activation of cyclin-dependent kinase 5 (Cdk5). However, only the effect of BDNF on KCC2 activity was dependent on a rise of intracellular calcium. Taken together, these data highlight distinct actions of BDNF on KCC2 and GABA(A) receptor in the regulation of GABAergic synaptic transmission.
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Affiliation(s)
- Ying Huang
- School of Biomedical Sciences, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, Hong Kong, China.
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Jiang R, Miyamoto A, Martz A, Specht A, Ishibashi H, Kueny-Stotz M, Chassaing S, Brouillard R, de Carvalho LP, Goeldner M, Nabekura J, Nielsen M, Grutter T. Retrochalcone derivatives are positive allosteric modulators at synaptic and extrasynaptic GABA(A) receptors in vitro. Br J Pharmacol 2011; 162:1326-39. [PMID: 21133889 DOI: 10.1111/j.1476-5381.2010.01142.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
BACKGROUND AND PURPOSE Flavonoids, important plant pigments, have been shown to allosterically modulate brain GABA(A) receptors (GABA(A)Rs). We previously reported that trans-6,4'-dimethoxyretrochalcone (Rc-OMe), a hydrolytic derivative of the corresponding flavylium salt, displayed nanomolar affinity for the benzodiazepine binding site of GABA(A)Rs. Here, we evaluate the functional modulations of Rc-OMe, along with two other synthetic derivatives trans-6-bromo-4'-methoxyretrochalcone (Rc-Br) and 4,3'-dimethoxychalcone (Ch-OMe) on GABA(A)Rs. EXPERIMENTAL APPROACH Whole-cell patch-clamp recordings were made to determine the effects of these derivatives on GABA(A)Rs expressed in HEK-293 cells and in hippocampal CA1 pyramidal and thalamic neurones from rat brain. KEY RESULTS Rc-OMe strongly potentiated GABA-evoked currents at recombinant α(1-4)β(2)γ(2s) and α(4)β(3)δ receptors but much less at α(1)β(2) and α(4)β(3). Rc-Br and Ch-OMe potentiated GABA-evoked currents at α(1)β(2)γ(2s). The potentiation by Rc-OMe was only reduced at α(1)H101Rβ(2)γ(2s) and α(1)β(2)N265Sγ(2s), mutations known to abolish the potentiation by diazepam and loreclezole respectively. The modulation of Rc-OMe and pentobarbital as well as by Rc-OMe and the neurosteroid 3α,21-dihydroxy-5α-pregnan-20-one was supra-additive. Rc-OMe modulation exhibited no apparent voltage-dependence, but was markedly dependent on GABA concentration. In neurones, Rc-Br slowed the decay of spontaneous inhibitory postsynaptic currents and both Rc-OMe and Rc-Br positively modulated synaptic and extrasynaptic diazepam-insensitive GABA(A)Rs. CONCLUSIONS AND IMPLICATIONS The trans-retrochalcones are powerful positive allosteric modulators of synaptic and extrasynaptic GABA(A)Rs. These novel modulators act through an original mode, thus making them putative drug candidates in the treatment of GABA(A)-related disorders in vivo.
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Affiliation(s)
- Ruotian Jiang
- Laboratoire de Biophysicochimie des Récepteurs Canaux, UMR 7199 CNRS, Conception et Application de Molécules Bioactives, Faculté de Pharmacie, Université de Strasbourg, Illkirch, France
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Lewis A, Wilson N, Stearns G, Johnson N, Nelson R, Brockerhoff SE. Celsr3 is required for normal development of GABA circuits in the inner retina. PLoS Genet 2011; 7:e1002239. [PMID: 21852962 PMCID: PMC3154962 DOI: 10.1371/journal.pgen.1002239] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2011] [Accepted: 06/28/2011] [Indexed: 12/30/2022] Open
Abstract
The identity of the specific molecules required for the process of retinal circuitry formation is largely unknown. Here we report a newly identified zebrafish mutant in which the absence of the atypical cadherin, Celsr3, leads to a specific defect in the development of GABAergic signaling in the inner retina. This mutant lacks an optokinetic response (OKR), the ability to visually track rotating illuminated stripes, and develops a super-normal b-wave in the electroretinogram (ERG). We find that celsr3 mRNA is abundant in the amacrine and ganglion cells of the retina, however its loss does not affect synaptic lamination within the inner plexiform layer (IPL) or amacrine cell number. We localize the ERG defect pharmacologically to a late-stage disruption in GABAergic modulation of ON-bipolar cell pathway and find that the DNQX-sensitive fast b1 component of the ERG is specifically affected in this mutant. Consistently, we find an increase in GABA receptors on mutant ON-bipolar terminals, providing a direct link between the observed physiological changes and alterations in GABA signaling components. Finally, using blastula transplantation, we show that the lack of an OKR is due, at least partially, to Celsr3-mediated defects within the brain. These findings support the previously postulated inner retina origin for the b1 component and reveal a new role for Celsr3 in the normal development of ON visual pathway circuitry in the inner retina. Visual information is transmitted through the retina from photoreceptors to bipolars to ganglion cells, the output neurons connecting to the brain. This vertical transmission of information is modulated by inhibitory lateral interneurons. Normal vision requires the proper transmission and processing of these neuronal signals. In the inner retina, amacrine cells are the main class of inhibitory interneurons. They modulate the information from bipolar to ganglion cells and are functionally responsible for adjusting image brightness and for detecting motion. Physiological studies have revealed important aspects of the mechanisms of inhibitory modulation, and anatomical studies have identified the many amacrine subclasses and their non-random arrangement within the retina. Although cell–cell interactions are thought to be critical for establishing the important physiological and morphological features of this cell class, the precise molecules and their functions are mostly unknown. In this paper we report the discovery of a mutant that identifies the atypical cell adhesion molecule, Celsr3, as critical for proper development of GABA-signaling pathways in the inner retina.
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Affiliation(s)
- Alaron Lewis
- Department of Biochemistry, University of Washington, Seattle, Washington, United States of America
| | - Neil Wilson
- Department of Biochemistry, University of Washington, Seattle, Washington, United States of America
| | - George Stearns
- Department of Biochemistry, University of Washington, Seattle, Washington, United States of America
| | - Nicolas Johnson
- Department of Biochemistry, University of Washington, Seattle, Washington, United States of America
| | - Ralph Nelson
- Basic Neurosciences Program, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Rockville, Maryland, United States of America
| | - Susan E. Brockerhoff
- Department of Biochemistry, University of Washington, Seattle, Washington, United States of America
- * E-mail:
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Corteen NL, Cole TM, Sarna A, Sieghart W, Swinny JD. Localization of GABA-A receptor alpha subunits on neurochemically distinct cell types in the rat locus coeruleus. Eur J Neurosci 2011; 34:250-62. [PMID: 21692880 DOI: 10.1111/j.1460-9568.2011.07740.x] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The locus coeruleus (LC) provides the major source of noradrenaline to the central nervous system and is modulated by neurochemically diverse afferents. LC function is central to arousal, memory, cognition and the stress response, with dysfunction of the LC-noradrenergic axis implicated in debilitating psychiatric disorders. The precise targeting of neurotransmitter receptors within the LC is essential for processing the information contained in diverse afferents and thus LC output. The inhibitory modulation of LC neurons is thought to be effected mainly through GABA-A receptors (GABA(A)Rs). Diverse GABA(A)Rs are pentameric complexes assembled from a repertoire of subunits resulting in substantial diversity in their molecular, functional and pharmacological properties throughout the brain. The precise location of distinct GABA(A) R subunits in subregions of the LC, and the neurochemical identity of the cells that express them, remains to be determined. Here, we show that the GABA(A)R alpha1 subunit is expressed exclusively in neurochemically and morphologically diverse non-noradrenergic cell types within the LC, which may innervate the principal noradrenergic cells. Thus, the GABA(A)R alpha1 subunit could provide a neurochemical signature for a pool of local circuit interneurons in the LC. In contrast, non-overlapping GABA(A)R alpha2 and alpha3 subunit-immunoreactive puncta were enriched on noradrenergic dendrites and, to a lesser extent, on somata. The study reveals a cell-type- and domain-specific expression pattern of distinct GABA(A)R subunits in the LC. These data will serve as a template for understanding inhibitory modulation of this region and facilitate more directed pharmacological strategies for disorders arising from the impairment of LC function.
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Affiliation(s)
- Nicole L Corteen
- Institute for Biomedical and Biomolecular Sciences, School of Pharmacy and Biomedical Sciences, University of Portsmouth, St Michael's Building, White Swan Road, Portsmouth PO1 2DT, UK
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Gross A, Sims RE, Swinny JD, Sieghart W, Bolam JP, Stanford IM. Differential localization of GABA(A) receptor subunits in relation to rat striatopallidal and pallidopallidal synapses. Eur J Neurosci 2011; 33:868-78. [PMID: 21219474 DOI: 10.1111/j.1460-9568.2010.07552.x] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
As a central integrator of basal ganglia function, the external segment of the globus pallidus (GP) plays a critical role in the control of voluntary movement. The GP is composed of a network of inhibitory GABA-containing projection neurons which receive GABAergic input from axons of the striatum (Str) and local collaterals of GP neurons. Here, using electrophysiological techniques and immunofluorescent labeling we have investigated the differential cellular distribution of α1, α2 and α3 GABA(A) receptor subunits in relation to striatopallidal (Str-GP) and pallidopallidal (GP-GP) synapses. Electrophysiological investigations showed that zolpidem (100 nm; selective for the α1 subunit) increased the amplitude and the decay time of both Str-GP and GP-GP IPSCs, indicating the presence of the α1 subunits at both synapses. However, the application of drugs selective for the α2, α3 and α5 subunits (zolpidem at 400 nm, L-838,417 and TP003) revealed differential effects on amplitude and decay time of IPSCs, suggesting the nonuniform distribution of non-α1 subunits. Immunofluorescence revealed widespread distribution of the α1 subunit at both soma and dendrites, while double- and triple-immunofluorescent labeling for parvalbumin, enkephalin, gephyrin and the γ2 subunit indicated strong immunoreactivity for GABA(A) α3 subunits in perisomatic synapses, a region mainly targeted by local axon collaterals. In contrast, immunoreactivity for synaptic GABA(A) α2 subunits was observed in dendritic compartments where striatal synapses are preferentially located. Due to the kinetic properties which each GABA(A) α subunit confers, this distribution is likely to contribute differentially to both physiological and pathological patterns of activity.
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Affiliation(s)
- A Gross
- Aston University, School of Life and Health Sciences, Birmingham, UK
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Identification and characterization of anesthetic targets by mouse molecular genetics approaches. Can J Anaesth 2010; 58:178-90. [PMID: 21174184 DOI: 10.1007/s12630-010-9414-1] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2010] [Accepted: 10/26/2010] [Indexed: 01/01/2023] Open
Abstract
PURPOSE It is now generally accepted that proteins are the primary targets of general anesthetics. However, the demonstration that the activity of a protein is altered by general anesthetics at clinically relevant concentrations in vitro does not provide direct evidence that this target mediates pharmacological actions of general anesthetics. Here we report on advances that have been made in identifying the contribution of individual ligand-gated ion channels to defined anesthetic endpoints using molecular mouse genetics. PRINCIPAL FINDINGS Gamma-aminobutyric acid (GABA)(A) receptor subtypes defined by the presence of the α1, α4, α5, β2, and β3 subunits and two-pore domain potassium channels (TASK-1, TASK-3, and TREK) have been discovered to mediate, at least in part, the hypnotic, immobilizing or amnestic actions of intravenous and volatile general anesthetics. Moreover, using tissues from genetically modified mice, specific functions of GABA(A) receptor subtypes in cortical and spinal neuronal networks were identified. CONCLUSION Genetically modified mice have been very useful for research on mechanisms of anesthesia and have contributed to the functional identification of general anesthetic targets and of the role of these targets in neuronal networks.
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Li G, Lillehoj HS, Lee KW, Jang SI, Marc P, Gay CG, Ritter GD, Bautista DA, Phillips K, Neumann AP, Rehberger TG, Siragusa GR. An outbreak of gangrenous dermatitis in commercial broiler chickens. Avian Pathol 2010; 39:247-53. [PMID: 20706880 DOI: 10.1080/03079457.2010.487517] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
The present report describes an outbreak of gangrenous dermatitis (GD) infection in a commercial poultry farm in Delaware involving 34-day-old broiler chickens. In addition to obvious clinical signs, some GD-affected broilers also showed severe fibrino-necrotic enteritis and large numbers of Gram-positive rods in the necrotic tissue. Histopathological findings included haemorrhage, degeneration and necrosis of parenchymatous cells, especially of skin, muscle, and intestine. Immunofluorescence staining revealed Clostridium-like bacilli in the skin and the intestine. Both Clostridium perfringens and Clostridium septicum genomic sequences were identified by polymerase chain reaction in bacterial cultures isolated from the skin, muscle, and intestine, and in the frozen tissues from the GD-affected birds. Serological analysis demonstrated that both affected and clinically healthy birds from the same house had high serum antibody titres against C. perfringens, C. septicum, Eimeria, chick anaemia virus, and infectious bursal disease virus. These results are discussed in the context of the relationship between the different Clostridium spp. and the pathogenesis of GD.
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Affiliation(s)
- Guangxing Li
- Animal and Natural Resources Institute, USDA-ARS, Beltsville, MD, USA
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Kohlmeier KA, Kristiansen U. GABAergic actions on cholinergic laterodorsal tegmental neurons: implications for control of behavioral state. Neuroscience 2010; 171:812-29. [PMID: 20884335 DOI: 10.1016/j.neuroscience.2010.09.034] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2010] [Revised: 09/17/2010] [Accepted: 09/17/2010] [Indexed: 11/30/2022]
Abstract
Cholinergic neurons of the pontine laterodorsal tegmentum (LDT) play a critical role in regulation of behavioral state. Therefore, elucidation of mechanisms that control their activity is vital for understanding of how switching between wakefulness, sleep and anesthetic states is effectuated. In vivo studies suggest that GABAergic mechanisms within the pons play a critical role in behavioral state switching. However, the postsynaptic, electrophysiological actions of GABA on LDT neurons, as well as the identity of GABA receptors present in the LDT mediating these actions is virtually unexplored. Therefore, we studied the actions of GABA agonists and antagonists on cholinergic LDT cells by performing patch clamp recordings in mouse brain slices. Under conditions where detection of Cl(-) -mediated events was optimized, GABA induced gabazine (GZ)-sensitive inward currents in the majority of LDT neurons. Post-synaptic location of GABA(A) receptors was demonstrated by persistence of muscimol-induced inward currents in TTX and low Ca(2+) solutions. THIP, a selective GABA(A) receptor agonist with a preference for δ-subunit containing GABA(A) receptors, induced inward currents, suggesting the existence of extrasynaptic GABA(A) receptors. LDT cells also possess GABA(B) receptors as baclofen-activated a TTX- and low Ca(2+)-resistant outward current that was attenuated by the GABA(B) antagonists CGP 55845 and saclofen. The tertiapin sensitivity of baclofen-induced outward currents suggests that a G(IRK) mediated this effect. Further, outward currents were never additive with those induced by application of carbachol, suggesting that they were mediated by activation of GABA(B) receptors linked to the same G(IRK) activated in these cells by muscarinic receptor stimulation. Activation of GABA(B) receptors inhibited Ca(2+) increases induced by a depolarizing voltage step shown previously to activate VOCCs in cholinergic LDT neurons. Baclofen-mediated reductions in depolarization-induced Ca(2+) were unaltered by prior emptying of intracellular Ca(2+) stores, but were abolished by low extracellular Ca(2+) and pre-application of nifedipine, indicating that activation of GABA(B) receptors inhibits influx of Ca(2+) involving L-type Ca(2+) channels. Presence of GABA(C) receptors is suggested by the induction of inward current by (E)-4- amino-2-butenoic acid (TACA) and its inhibition by 1,2,5,6-tetrahydropyridine-4-ylmethylphosphinic (TPMPA), a relatively selective agonist and antagonist, respectively, of GABA(C) receptors. All of these GABA-mediated actions were found to occur in histochemically-identified cholinergic neurons. Taken together, these data indicate for the first time that cholinergic neurons of the LDT exhibit functional GABA(A, B and C) receptors, including extrasynaptically located GABA(A) receptors, which may be tonically activated by synaptic overflow of GABA. Accordingly, the activity of cholinergic LDT neurons is likely to be significantly affected by GABAergic tone within the nucleus, and so, demonstrated effects of GABA on behavioral state may be mediated, in part, via direct actions on cholinergic neurons in the LDT.
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Affiliation(s)
- K A Kohlmeier
- Department of Pharmacology and Pharmacotherapy, The Pharmaceutical Faculty, University of Copenhagen, Universitetsparken 2, 2100 Copenhagen, Denmark.
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Jang SI, Lillehoj HS, Lee SH, Lee KW, Park MS, Bauchan GR, Lillehoj EP, Bertrand F, Dupuis L, Deville S. Immunoenhancing effects of Montanide™ ISA oil-based adjuvants on recombinant coccidia antigen vaccination against Eimeria acervulina infection. Vet Parasitol 2010; 172:221-8. [DOI: 10.1016/j.vetpar.2010.04.042] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2010] [Revised: 04/29/2010] [Accepted: 04/30/2010] [Indexed: 12/01/2022]
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