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Activation of the Rat α1β2ε GABA A Receptor by Orthosteric and Allosteric Agonists. Biomolecules 2022; 12:biom12070868. [PMID: 35883422 PMCID: PMC9312946 DOI: 10.3390/biom12070868] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2022] [Revised: 06/10/2022] [Accepted: 06/17/2022] [Indexed: 02/04/2023] Open
Abstract
GABAA receptors are a major contributor to fast inhibitory neurotransmission in the brain. The receptors are activated upon binding the transmitter GABA or allosteric agonists including a number of GABAergic anesthetics and neurosteroids. Functional receptors can be formed by various combinations of the nineteen GABAA subunits cloned to date. GABAA receptors containing the ε subunit exhibit a significant degree of constitutive activity and have been suggested to be unresponsive to allosteric agents. In this study, we have characterized the functional properties of the rat α1β2ε GABAA receptor. We confirm that the α1β2ε receptor exhibits a higher level of constitutive activity than typical of GABAA receptors and show that it is inefficaciously activated by the transmitter and the allosteric agonists propofol, pentobarbital, and allopregnanolone. Manipulations intended to alter ε subunit expression and receptor stoichiometry were largely without effect on receptor properties including sensitivity to GABA and allosteric agonists. Surprisingly, amino acid substitutions at the conserved 9' and 6' positions in the second transmembrane (TM2) domain in the ε subunit did not elicit the expected functional effects of increased constitutive activity and resistance to the channel blocker picrotoxin, respectively. We tested the accessibility of TM2 residues mutated to cysteine using the cysteine-modifying reagent 4-(hydroxymercuri)benzoic acid and found a unique pattern of water-accessible residues in the ε subunit.
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Aytac HM, Oyaci Y, Aydin PC, Pehlivan M, Pehlivan S. COMTVal158Met polymorphism is associated with ecstasy (MDMA)-induced psychotic symptoms in the Turkish population. NEUROSCIENCES (RIYADH, SAUDI ARABIA) 2022; 27:24-30. [PMID: 35017287 PMCID: PMC9037567 DOI: 10.17712/nsj.2022.1.20210045] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 04/13/2021] [Accepted: 09/14/2021] [Indexed: 01/10/2023]
Abstract
OBJECTIVES To investigate catechol-O-methyltransferase (COMT) Val158Met gene polymorphism in MDMA use disorder (MUD) by comparing genotype distributions between MUD patients and healthy controls considering clinical parameters. METHODS Eighty-two MUD patients' were consecutively admitted to the outpatient psychiatry clinic in May 2019-January 2020, and 95 healthy volunteers were included in the case-control study. We used the polymerase chain reaction (PCR) and restriction fragment length polymorphism (RFLP) to determine COMT Val158Met polymorphism. RESULTS The COMT Val158Met genotype distribution and allele frequencies of the MUD patient group were significantly different from the healthy control group. The Met/Met genotype (OR: 2.692; 95% Cl: 1.272-5.698; p=0.008) and Met allele frequencies (OR: 1.716; 95% Cl: 1.118-2.633; p=0.013) were significantly higher in the control group than in MUD patients. When the COMT Val158Met genotype and allele frequency distributions were compared between 2 groups according to the psychotic symptoms in the MUD patient group, the COMT Val158Met genotype distributions were significantly different between the groups of patients. The percentage of patients with the Val/Val genotype was significantly lower in MUD patients with a psychotic symptom than the MUD patients without a psychotic symptom (OR: 2.625; 95% Cl: 1.069-6.446; p=0.033). CONCLUSION The COMT Val158Met gene polymorphism was found to be related to the MUD-diagnosed Turkish patients and MDMA-induced psychotic symptoms.
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Affiliation(s)
- Hasan Mervan Aytac
- From the Department of Psychiatry (Aytac), Basaksehir Cam and Sakura City Hospital; Department of Medical Biology (Oyaci, Pehlivan), Istanbul Faculty of Medicine, Istanbul University, and from the Department of Psychiatry (Cetinay Aydin), Bakirkoy Research and Training Hospital for Psychiatry, Neurology and Neurosurgery, Psychiatry Clinic, University of Health Sciences, Istanbul, and from the Department of Hematology (Pehlivan), Gaziantep University, Faculty of Medicine, Gaziantep, Turkey
| | - Yasemin Oyaci
- From the Department of Psychiatry (Aytac), Basaksehir Cam and Sakura City Hospital; Department of Medical Biology (Oyaci, Pehlivan), Istanbul Faculty of Medicine, Istanbul University, and from the Department of Psychiatry (Cetinay Aydin), Bakirkoy Research and Training Hospital for Psychiatry, Neurology and Neurosurgery, Psychiatry Clinic, University of Health Sciences, Istanbul, and from the Department of Hematology (Pehlivan), Gaziantep University, Faculty of Medicine, Gaziantep, Turkey
| | - Pinar Cetinay Aydin
- From the Department of Psychiatry (Aytac), Basaksehir Cam and Sakura City Hospital; Department of Medical Biology (Oyaci, Pehlivan), Istanbul Faculty of Medicine, Istanbul University, and from the Department of Psychiatry (Cetinay Aydin), Bakirkoy Research and Training Hospital for Psychiatry, Neurology and Neurosurgery, Psychiatry Clinic, University of Health Sciences, Istanbul, and from the Department of Hematology (Pehlivan), Gaziantep University, Faculty of Medicine, Gaziantep, Turkey
| | - Mustafa Pehlivan
- From the Department of Psychiatry (Aytac), Basaksehir Cam and Sakura City Hospital; Department of Medical Biology (Oyaci, Pehlivan), Istanbul Faculty of Medicine, Istanbul University, and from the Department of Psychiatry (Cetinay Aydin), Bakirkoy Research and Training Hospital for Psychiatry, Neurology and Neurosurgery, Psychiatry Clinic, University of Health Sciences, Istanbul, and from the Department of Hematology (Pehlivan), Gaziantep University, Faculty of Medicine, Gaziantep, Turkey
| | - Sacide Pehlivan
- From the Department of Psychiatry (Aytac), Basaksehir Cam and Sakura City Hospital; Department of Medical Biology (Oyaci, Pehlivan), Istanbul Faculty of Medicine, Istanbul University, and from the Department of Psychiatry (Cetinay Aydin), Bakirkoy Research and Training Hospital for Psychiatry, Neurology and Neurosurgery, Psychiatry Clinic, University of Health Sciences, Istanbul, and from the Department of Hematology (Pehlivan), Gaziantep University, Faculty of Medicine, Gaziantep, Turkey
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Ondřejíková L, Pařízek A, Šimják P, Vejražková D, Velíková M, Anderlová K, Vosátková M, Krejčí H, Koucký M, Kancheva R, Dušková M, Vaňková M, Bulant J, Hill M. Altered Steroidome in Women with Gestational Diabetes Mellitus: Focus on Neuroactive and Immunomodulatory Steroids from the 24th Week of Pregnancy to Labor. Biomolecules 2021; 11:biom11121746. [PMID: 34944390 PMCID: PMC8698588 DOI: 10.3390/biom11121746] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2021] [Revised: 11/12/2021] [Accepted: 11/20/2021] [Indexed: 12/19/2022] Open
Abstract
Gestational diabetes mellitus (GDM) is a complication in pregnancy, but studies focused on the steroidome in patients with GDM are not available in the public domain. This article evaluates the steroidome in GDM+ and GDM- women and its changes from 24 weeks (± of gestation) to labor. The study included GDM+ (n = 44) and GDM- women (n = 33), in weeks 24-28, 30-36 of gestation and at labor and mixed umbilical blood after delivery. Steroidomic data (101 steroids quantified by GC-MS/MS) support the concept that the increasing diabetogenic effects with the approaching term are associated with mounting progesterone levels. The GDM+ group showed lower levels of testosterone (due to reduced AKR1C3 activity), estradiol (due to a shift from the HSD17B1 towards HSD17B2 activity), 7-oxygenated androgens (competing with cortisone for HSD11B1 and shifting the balance from diabetogenic cortisol towards the inactive cortisone), reduced activities of SRD5As, and CYP17A1 in the hydroxylase but higher CYP17A1 activity in the lyase step. With the approaching term, the authors found rising activities of CYP3A7, AKR1C1, CYP17A1 in its hydroxylase step, but a decline in its lyase step, rising conjugation of neuroinhibitory and pregnancy-stabilizing steroids and weakening AKR1D1 activity.
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Affiliation(s)
- Leona Ondřejíková
- Institute of Endocrinology, 116 94 Prague, Czech Republic; (L.O.); (D.V.); (M.V.); (M.V.); (R.K.); (M.D.); (M.V.); (J.B.)
| | - Antonín Pařízek
- Department of Gynecology and Obstetrics, First Faculty of Medicine, General University Hospital in Prague, Charles University in Prague, 128 08 Prague, Czech Republic; (A.P.); (P.Š.); (K.A.); (H.K.); (M.K.)
| | - Patrik Šimják
- Department of Gynecology and Obstetrics, First Faculty of Medicine, General University Hospital in Prague, Charles University in Prague, 128 08 Prague, Czech Republic; (A.P.); (P.Š.); (K.A.); (H.K.); (M.K.)
| | - Daniela Vejražková
- Institute of Endocrinology, 116 94 Prague, Czech Republic; (L.O.); (D.V.); (M.V.); (M.V.); (R.K.); (M.D.); (M.V.); (J.B.)
| | - Marta Velíková
- Institute of Endocrinology, 116 94 Prague, Czech Republic; (L.O.); (D.V.); (M.V.); (M.V.); (R.K.); (M.D.); (M.V.); (J.B.)
| | - Kateřina Anderlová
- Department of Gynecology and Obstetrics, First Faculty of Medicine, General University Hospital in Prague, Charles University in Prague, 128 08 Prague, Czech Republic; (A.P.); (P.Š.); (K.A.); (H.K.); (M.K.)
| | - Michala Vosátková
- Institute of Endocrinology, 116 94 Prague, Czech Republic; (L.O.); (D.V.); (M.V.); (M.V.); (R.K.); (M.D.); (M.V.); (J.B.)
| | - Hana Krejčí
- Department of Gynecology and Obstetrics, First Faculty of Medicine, General University Hospital in Prague, Charles University in Prague, 128 08 Prague, Czech Republic; (A.P.); (P.Š.); (K.A.); (H.K.); (M.K.)
| | - Michal Koucký
- Department of Gynecology and Obstetrics, First Faculty of Medicine, General University Hospital in Prague, Charles University in Prague, 128 08 Prague, Czech Republic; (A.P.); (P.Š.); (K.A.); (H.K.); (M.K.)
| | - Radmila Kancheva
- Institute of Endocrinology, 116 94 Prague, Czech Republic; (L.O.); (D.V.); (M.V.); (M.V.); (R.K.); (M.D.); (M.V.); (J.B.)
| | - Michaela Dušková
- Institute of Endocrinology, 116 94 Prague, Czech Republic; (L.O.); (D.V.); (M.V.); (M.V.); (R.K.); (M.D.); (M.V.); (J.B.)
| | - Markéta Vaňková
- Institute of Endocrinology, 116 94 Prague, Czech Republic; (L.O.); (D.V.); (M.V.); (M.V.); (R.K.); (M.D.); (M.V.); (J.B.)
| | - Josef Bulant
- Institute of Endocrinology, 116 94 Prague, Czech Republic; (L.O.); (D.V.); (M.V.); (M.V.); (R.K.); (M.D.); (M.V.); (J.B.)
| | - Martin Hill
- Institute of Endocrinology, 116 94 Prague, Czech Republic; (L.O.); (D.V.); (M.V.); (M.V.); (R.K.); (M.D.); (M.V.); (J.B.)
- Correspondence: ; Tel.: +420-224-905-246
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Electrophysiology of ionotropic GABA receptors. Cell Mol Life Sci 2021; 78:5341-5370. [PMID: 34061215 PMCID: PMC8257536 DOI: 10.1007/s00018-021-03846-2] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2020] [Revised: 04/02/2021] [Accepted: 04/23/2021] [Indexed: 10/30/2022]
Abstract
GABAA receptors are ligand-gated chloride channels and ionotropic receptors of GABA, the main inhibitory neurotransmitter in vertebrates. In this review, we discuss the major and diverse roles GABAA receptors play in the regulation of neuronal communication and the functioning of the brain. GABAA receptors have complex electrophysiological properties that enable them to mediate different types of currents such as phasic and tonic inhibitory currents. Their activity is finely regulated by membrane voltage, phosphorylation and several ions. GABAA receptors are pentameric and are assembled from a diverse set of subunits. They are subdivided into numerous subtypes, which differ widely in expression patterns, distribution and electrical activity. Substantial variations in macroscopic neural behavior can emerge from minor differences in structure and molecular activity between subtypes. Therefore, the diversity of GABAA receptors widens the neuronal repertoire of responses to external signals and contributes to shaping the electrical activity of neurons and other cell types.
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Tossell K, Dodhia RA, Galet B, Tkachuk O, Ungless MA. Tonic GABAergic inhibition, via GABA A receptors containing αβƐ subunits, regulates excitability of ventral tegmental area dopamine neurons. Eur J Neurosci 2021; 53:1722-1737. [PMID: 33522050 PMCID: PMC8651010 DOI: 10.1111/ejn.15133] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2019] [Revised: 12/15/2020] [Accepted: 01/18/2021] [Indexed: 12/13/2022]
Abstract
The activity of midbrain dopamine neurons is strongly regulated by fast synaptic inhibitory γ‐Aminobutyric acid (GABA)ergic inputs. There is growing evidence in other brain regions that low concentrations of ambient GABA can persistently activate certain subtypes of GABAA receptor to generate a tonic current. However, evidence for a tonic GABAergic current in midbrain dopamine neurons is limited. To address this, we conducted whole‐cell recordings from ventral tegmental area (VTA) dopamine neurons in brain slices from mice. We found that application of GABAA receptor antagonists decreased the holding current, indicating the presence of a tonic GABAergic input. Global increases in GABA release, induced by either a nitric oxide donor or inhibition of GABA uptake, further increased this tonic current. Importantly, prolonged inhibition of the firing activity of local GABAergic neurons abolished the tonic current. A combination of pharmacology and immunohistochemistry experiments suggested that, unlike common examples of tonic inhibition, this current may be mediated by a relatively unusual combination of α4βƐ subunits. Lastly, we found that the tonic current reduced excitability in dopamine neurons suggesting a subtractive effect on firing activity.
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Affiliation(s)
- Kyoko Tossell
- MRC London Institute of Medical Sciences (LMS), London, UK.,Institute of Clinical Sciences (ICS), Faculty of Medicine, Imperial College London, London, UK
| | - Rakesh A Dodhia
- MRC London Institute of Medical Sciences (LMS), London, UK.,Institute of Clinical Sciences (ICS), Faculty of Medicine, Imperial College London, London, UK
| | - Benjamin Galet
- MRC London Institute of Medical Sciences (LMS), London, UK.,Institute of Clinical Sciences (ICS), Faculty of Medicine, Imperial College London, London, UK
| | - Olga Tkachuk
- MRC London Institute of Medical Sciences (LMS), London, UK.,Institute of Clinical Sciences (ICS), Faculty of Medicine, Imperial College London, London, UK
| | - Mark A Ungless
- MRC London Institute of Medical Sciences (LMS), London, UK.,Institute of Clinical Sciences (ICS), Faculty of Medicine, Imperial College London, London, UK
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Lin S, Li R, Wang Y, Li M, Wang L, Zhen X, Liu P. Increased maternal serum hCG concentrations in the presence of a female fetus as early as 2 weeks after IVF-ET. J Gynecol Obstet Hum Reprod 2021; 50:102053. [PMID: 33401030 DOI: 10.1016/j.jogoh.2020.102053] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2020] [Revised: 09/28/2020] [Accepted: 12/29/2020] [Indexed: 12/23/2022]
Abstract
BACKGROUND Maternal serum human chorionic gonadotropin (hCG) is produced in trophoblast cells during pregnancy. Whether there are sex-related growth differences of hCG concentrations in early pregnancy is still controversial. OBJECTIVE To explore the association between hCG concentrations and fetal sex as early as 2 weeks after in vitro fertilization and embryo transfer (IVF-ET). METHODS This study involved 6669 women ≤ 38 years of age. These 6669 patients all delivered singletons; 3531 had a male fetus and 3138 had a female fetus. The maternal serum hCG concentrations on Day 14 and Day 21 were determined using a Beckman DxI800 immunoassay system. RESULTS Among the 6669 patients who delivered singletons, 3531 had a male fetus and 3138 had a female fetus. The hCG concentrations on day 14 of gestation were 516.12 (342.12-757.34) IU/L in the group of male fetuses and 552.69 (359.35-772.83) IU/L in group of female fetuses. The hCG concentration on day 21 was 8839.60 (5975.00-12615.00) IU/L in male fetuses and 9289.10 (6162.00-13146.00) IU/L in female fetuses. Maternal serum hCG levels were significantly higher in those with female fetuses than those with male fetuses. After adjusting for confounding factors, the hCG levels were significantly associated with fetal sex. CONCLUSIONS Our results showed pregnant women with female fetuses have significantly higher hCG levels than those bearing male fetuses.
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Affiliation(s)
- Shengli Lin
- Center for Reproductive Medicine, Department of Obstetrics and Gynecology, National Clinical Research Center for Obstetrics and Gynecology, Peking University Third Hospital, Beijing, China.
| | - Rong Li
- Center for Reproductive Medicine, Department of Obstetrics and Gynecology, National Clinical Research Center for Obstetrics and Gynecology, Peking University Third Hospital, Beijing, China
| | - Yapeng Wang
- Center for Reproductive Medicine, Department of Obstetrics and Gynecology, National Clinical Research Center for Obstetrics and Gynecology, Peking University Third Hospital, Beijing, China
| | - Ming Li
- Center for Reproductive Medicine, Department of Obstetrics and Gynecology, National Clinical Research Center for Obstetrics and Gynecology, Peking University Third Hospital, Beijing, China
| | - Lina Wang
- Center for Reproductive Medicine, Department of Obstetrics and Gynecology, National Clinical Research Center for Obstetrics and Gynecology, Peking University Third Hospital, Beijing, China
| | - Xiumei Zhen
- Center for Reproductive Medicine, Department of Obstetrics and Gynecology, National Clinical Research Center for Obstetrics and Gynecology, Peking University Third Hospital, Beijing, China
| | - Ping Liu
- Center for Reproductive Medicine, Department of Obstetrics and Gynecology, National Clinical Research Center for Obstetrics and Gynecology, Peking University Third Hospital, Beijing, China
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7
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Markus F, Angelini C, Trimouille A, Rudolf G, Lesca G, Goizet C, Lasseaux E, Arveiler B, van Slegtenhorst M, Brooks AS, Abou Jamra R, Korenke GC, Neidhardt J, Owczarek-Lipska M. Rare variants in the GABA A receptor subunit ε identified in patients with a wide spectrum of epileptic phenotypes. Mol Genet Genomic Med 2020; 8:e1388. [PMID: 32588540 PMCID: PMC7507344 DOI: 10.1002/mgg3.1388] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2020] [Revised: 05/29/2020] [Accepted: 05/31/2020] [Indexed: 01/08/2023] Open
Abstract
Background Epilepsy belongs to a group of chronic and highly heterogeneous brain disorders. Many types of epilepsy and epileptic syndromes are caused by genetic factors. The neural amino acid y‐aminobutyric acid (GABA) is a major inhibitory neurotransmitter in the mammalian central nervous system. It regulates activity of channel pores by binding to transmembrane GABA‐receptors (GABRs). The GABRs are heteropentamers assembled from different receptor subunits (α1‐6, β1‐3, γ1‐3, δ, ε, θ, π, and ρ1‐3). Several epileptic disorders are caused by mutations in genes encoding single GABRs. Methods We applied trio‐ and single‐whole exome sequencing to search for genetic sequence variants associated with a wide range of epileptic phenotypes accompanied by intellectual disability and/or global developmental delay in the investigated patients. Results We identified four hemizygous sequence variants in the GABAA receptor subunit ε gene (GABRE), including one nonsense (NM_004961.3: c.399C>A, p.Tyr133*), two missense variants (NM_004961.3: c.664G>A, p.Glu222Lys; NM_004961.3: c.1045G>A, p.Val349Ile), and one variant affecting the translation initiation codon (NM_004961.3: c.1A>G, p.Met1?) in four unrelated families. Conclusion Our clinical and molecular genetic findings suggest that GABRE is a likely candidate gene for epilepsy. Nevertheless, functional studies are necessary to better understand pathogenicity of the GABRE‐mutations and their associations with epileptic phenotypes.
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Affiliation(s)
- Fenja Markus
- Junior Research Group, Genetics of Childhood Brain Malformations, Faculty VI-School of Medicine and Health Sciences, University of Oldenburg, Oldenburg, Germany.,Human Genetics, Faculty VI-School of Medicine and Health Sciences, University of Oldenburg, Oldenburg, Germany
| | - Chloé Angelini
- Service de Génétique médicale, CHU de Bordeaux, Bordeaux, France
| | | | - Gabrielle Rudolf
- CNRS U7104, INSERM U1258, Institut de Génétique et de Biologie Moléculaire et Cellulaire, Illkirch, France.,Service de Neurologie, Centre de Références des Maladies Neurogénétique Rares, Hôpitaux Universitaires de Strasbourg, Strasbourg, France
| | - Gaetan Lesca
- Genetics department, Lyon University Hospital and University of Lyon, Lyon, France
| | - Cyril Goizet
- Service de Génétique médicale, CHU de Bordeaux, Bordeaux, France.,CNRS U7104, INSERM U1258, Institut de Génétique et de Biologie Moléculaire et Cellulaire, Illkirch, France
| | - Eulalie Lasseaux
- Service de Génétique médicale, CHU de Bordeaux, Bordeaux, France
| | - Benoit Arveiler
- Service de Génétique médicale, CHU de Bordeaux, Bordeaux, France
| | - Marjon van Slegtenhorst
- Department of Clinical Genetics, Erasmus MC University Medical Center, Rotterdam, The Netherlands
| | - Alice S Brooks
- Department of Clinical Genetics, Erasmus MC University Medical Center, Rotterdam, The Netherlands
| | - Rami Abou Jamra
- Institute of Human Genetics, University Medical Center Leipzig, Leipzig, Germany
| | | | - John Neidhardt
- Human Genetics, Faculty VI-School of Medicine and Health Sciences, University of Oldenburg, Oldenburg, Germany.,Research Center Neurosensory Science, University of Oldenburg, Oldenburg, Germany
| | - Marta Owczarek-Lipska
- Junior Research Group, Genetics of Childhood Brain Malformations, Faculty VI-School of Medicine and Health Sciences, University of Oldenburg, Oldenburg, Germany.,Human Genetics, Faculty VI-School of Medicine and Health Sciences, University of Oldenburg, Oldenburg, Germany
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Abstract
Current GABAergic sleep-promoting medications were developed pragmatically, without making use of the immense diversity of GABAA receptors. Pharmacogenetic experiments are leading to an understanding of the circuit mechanisms in the hypothalamus by which zolpidem and similar compounds induce sleep at α2βγ2-type GABAA receptors. Drugs acting at more selective receptor types, for example, at receptors containing the α2 and/or α3 subunits expressed in hypothalamic and brain stem areas, could in principle be useful as hypnotics/anxiolytics. A highly promising sleep-promoting drug, gaboxadol, which activates αβδ-type receptors failed in clinical trials. Thus, for the time being, drugs such as zolpidem, which work as positive allosteric modulators at GABAA receptors, continue to be some of the most effective compounds to treat primary insomnia.
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Affiliation(s)
- W Wisden
- Department Life Sciences, Imperial College London, London, SW7 2AZ, UK.
| | - X Yu
- Department Life Sciences, Imperial College London, London, SW7 2AZ, UK
| | - N P Franks
- Department Life Sciences, Imperial College London, London, SW7 2AZ, UK
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9
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Berggaard N, Witter MP, van der Want JJL. GABA A Receptor Subunit α3 in Network Dynamics in the Medial Entorhinal Cortex. Front Syst Neurosci 2019; 13:10. [PMID: 30930755 PMCID: PMC6428777 DOI: 10.3389/fnsys.2019.00010] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2018] [Accepted: 02/25/2019] [Indexed: 12/11/2022] Open
Abstract
Layer II of the medial entorhinal cortex (MEC LII) contains the largest number of spatially modulated grid cells and is one of the first regions in the brain to express Alzheimer's disease (AD)-related pathology. The most common principal cell type in MEC LII, reelin-expressing stellate cells, are grid cell candidates. Recently we found evidence that γ-aminobutyric acid (GABA)A receptor subunits show a specific distribution in MEC LII, in which GABAA α3 is selectively associated with reelin-positive neurons, with limited association with the other principal cell type, calbindin (CB)-positive pyramidal neurons. Furthermore, the expression of α3 subunit decreases in mice between P15 and P25, which coincides with the emergence of stable grid cell activity. It has been shown that the α3 subunit undergoes specific developmental changes and that it may exert pro-inflammatory actions if improperly regulated. In this review article, we evaluate the changing kinetics of α3-GABAA receptors (GABAARs). during development in relation to α3-subunit expression pattern in MEC LII and conclude that α3 could be closely related to the stabilization of grid cell activity and theta oscillations. We further conclude that dysregulated α3 may be a driving factor in early AD pathology.
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Affiliation(s)
- Nina Berggaard
- Department of Clinical and Molecular Medicine, Faculty of Medicine and Health Sciences, Norwegian University of Science and Technology, Trondheim, Norway
| | - Menno P Witter
- Center for Computational Neuroscience, Egil and Pauline Braathen and Fred Kavli Center for Cortical Microcircuits, Kavli Institute for Systems Neuroscience, NTNU Norwegian University of Science and Technology, Trondheim, Norway
| | - Johannes J L van der Want
- Department of Clinical and Molecular Medicine, Faculty of Medicine and Health Sciences, Norwegian University of Science and Technology, Trondheim, Norway
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10
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Sieghart W, Savić MM. International Union of Basic and Clinical Pharmacology. CVI: GABAA Receptor Subtype- and Function-selective Ligands: Key Issues in Translation to Humans. Pharmacol Rev 2018; 70:836-878. [DOI: 10.1124/pr.117.014449] [Citation(s) in RCA: 105] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
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11
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Mir FR, Carrer HF, Cambiasso MJ. Sex differences in depolarizing actions of GABA A receptor activation in rat embryonic hypothalamic neurons. Eur J Neurosci 2016; 45:521-527. [PMID: 27888546 DOI: 10.1111/ejn.13467] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2016] [Revised: 10/27/2016] [Accepted: 11/02/2016] [Indexed: 11/28/2022]
Abstract
GABAA receptor activation exerts trophic actions in immature neurons through depolarization of resting membrane potential. The switch to its classical hyperpolarizing role is developmentally regulated. Previous results suggest that a hormonally biased sex difference exists at the onset of the switch in hypothalamic neurons. The aim of this work was to evaluate sex differences in GABAA receptor function of hypothalamic neurons before brain masculinization by gonadal hormones. Hypothalamic cells were obtained from embryonic day 16 male and female rat foetuses, 2 days before the peak of testosterone production by the foetal testis, and grown in vitro for 9 days. Whole-cell and perforated patch-clamp recordings were carried out in order to measure several electrophysiological parameters. Our results show that there are more male than female neurons responding with depolarization to muscimol. Additionally, among cells with depolarizing responses, males have higher and longer lasting responses than females. These results highlight the relevance of differences in neural cell sex irrespective of exposure to sex hormones.
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Affiliation(s)
- Franco R Mir
- Laboratory of Neurophysiology, Instituto de Investigación Médica Mercedes y Martín Ferreyra, INIMEC-CONICET-Universidad Nacional de Córdoba, Friuli 2434, 5016, Córdoba, Argentina
| | - Hugo F Carrer
- Laboratory of Neurophysiology, Instituto de Investigación Médica Mercedes y Martín Ferreyra, INIMEC-CONICET-Universidad Nacional de Córdoba, Friuli 2434, 5016, Córdoba, Argentina
| | - María J Cambiasso
- Laboratory of Neurophysiology, Instituto de Investigación Médica Mercedes y Martín Ferreyra, INIMEC-CONICET-Universidad Nacional de Córdoba, Friuli 2434, 5016, Córdoba, Argentina.,Departamento de Biología Bucal, Facultad de Odontología, Universidad Nacional de Córdoba, Córdoba, Argentina
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12
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MacKenzie G, Maguire J. Neurosteroids and GABAergic signaling in health and disease. Biomol Concepts 2015; 4:29-42. [PMID: 25436563 DOI: 10.1515/bmc-2012-0033] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2012] [Accepted: 10/12/2012] [Indexed: 11/15/2022] Open
Abstract
Endogenous neurosteroids such as allopregnanolone, allotetrahydrodeoxycorticosterone, and androstanediol are synthesized either de novo in the brain from cholesterol or are generated from the local metabolism of peripherally derived progesterone or corticosterone. Fluctuations in neurosteroid concentrations are important in the regulation of a number of physiological responses including anxiety and stress, reproductive, and sexual behaviors. These effects are mediated in part by the direct binding of neurosteroids to γ-aminobutyric acid type-A receptors (GABAARs), resulting in the potentiation of GABAAR-mediated currents. Extrasynaptic GABAARs containing the δ subunit, which contribute to the tonic conductance, are particularly sensitive to low nanomolar concentrations of neurosteroids and are likely their preferential target. Considering the large charge transfer generated by these persistently open channels, even subtle changes in neurosteroid concentrations can have a major impact on neuronal excitability. Consequently, aberrant levels of neurosteroids have been implicated in numerous disorders, including, but not limited to, anxiety, neurodegenerative diseases, alcohol abuse, epilepsy, and depression. Here we review the modulation of GABAAR by neurosteroids and the consequences for health and disease.
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13
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Subhani S, Jamil K. Molecular docking of chemotherapeutic agents to CYP3A4 in non-small cell lung cancer. Biomed Pharmacother 2015. [DOI: 10.1016/j.biopha.2015.05.018] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022] Open
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Boychuk CR, Halmos KC, Smith BN. Diabetes induces GABA receptor plasticity in murine vagal motor neurons. J Neurophysiol 2015; 114:698-706. [PMID: 25995347 DOI: 10.1152/jn.00209.2015] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2015] [Accepted: 05/19/2015] [Indexed: 01/07/2023] Open
Abstract
Autonomic dysregulation accompanies type-1 diabetes, and synaptic regulation of parasympathetic preganglionic motor neurons in the dorsal motor nucleus of the vagus (DMV) is altered after chronic hyperglycemia/hypoinsulinemia. Tonic gamma-aminobutyric acid A (GABAA) inhibition prominently regulates DMV neuron activity, which contributes to autonomic control of energy homeostasis. This study investigated persistent effects of chronic hyperglycemia/hypoinsulinemia on GABAA receptor-mediated inhibition in the DMV after streptozotocin-induced type-1 diabetes using electrophysiological recordings in vitro, quantitative (q)RT-PCR, and immunohistochemistry. Application of the nonspecific GABAA receptor agonist muscimol evoked an outward current of significantly larger amplitude in DMV neurons from diabetic mice than controls. Results from application of 4,5,6,7-tetrahydroisoxazolo[5,4-c]pyridin-3-ol hydrochloride (THIP), a δ-subunit agonist, suggested that GABAA receptors containing δ-subunits contributed to the enhanced inducible tonic GABA current in diabetic mice. Sensitivity to THIP of inhibitory postsynaptic currents in DMV neurons from diabetic mice was also increased. Results from qRT-PCR and immunohistochemical analyses indicated that the altered GABAergic inhibition may be related to increased trafficking of GABAA receptors that contain the δ-subunit, rather than an expression change. Overall these findings suggest increased sensitivity of δ-subunit containing GABAA receptors after several days of hyperglycemia/hypoinsulinemia, which dramatically alters GABAergic inhibition of DMV neurons and could contribute to diabetic autonomic dysregulation.
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Affiliation(s)
- C R Boychuk
- Department of Physiology, University of Kentucky College of Medicine, Lexington, Kentucky
| | - K Cs Halmos
- Department of Physiology, University of Kentucky College of Medicine, Lexington, Kentucky
| | - B N Smith
- Department of Physiology, University of Kentucky College of Medicine, Lexington, Kentucky
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Bhandage AK, Hellgren C, Jin Z, Olafsson EB, Sundström-Poromaa I, Birnir B. Expression of GABA receptors subunits in peripheral blood mononuclear cells is gender dependent, altered in pregnancy and modified by mental health. Acta Physiol (Oxf) 2015; 213:575-85. [PMID: 25529063 DOI: 10.1111/apha.12440] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2014] [Revised: 12/05/2014] [Accepted: 12/15/2014] [Indexed: 12/31/2022]
Abstract
AIM The concept of nerve-driven immunity recognizes a link between the nervous and the immune system. γ-aminobutyric acid (GABA) is the main inhibitory neurotransmitter in the brain, and receptors activated by GABA can be expressed by immune cells. Here, we examined whether the expression of GABA receptors and chloride transporters in human peripheral blood mononuclear cells (PBMCs) was influenced by gender, pregnancy or mental health. METHODS We used RT-qPCR to determine the mRNA expression level in PBMCs from men (n = 16), non-pregnant women (n = 19), healthy pregnant women (n = 27) and depressed pregnant women (n = 15). RESULTS The ρ2 subunit had the most prominent expression level of the GABA-A receptor subunits in all samples. The δ and ρ2 subunits were up-regulated by pregnancy, whereas the ε subunit was more frequently expressed in healthy pregnant women than non-pregnant women who, in turn, commonly expressed the α6 and the γ2 subunits. The β1 and ε subunits expression was altered by depression in pregnant women. The GABA-B1 receptor was up-regulated by depression in pregnant women, while the transporters NKCC1 and KCC4 were down-regulated by pregnancy. The changes recorded in the mRNA expression levels imply participation of GABA receptors in establishing and maintaining tolerance in pregnancy. Importantly, the correlation of mental health with the expression of specific receptor subunits reveals a connection between the immune cells and the brain. Biomarkers for mental health may be identified in PBMCs. CONCLUSION The results demonstrate the impact gender, pregnancy and mental health have on the expression of GABA receptors and chloride transporters expressed in human PBMCs.
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Affiliation(s)
- A. K. Bhandage
- Department of Neuroscience; Uppsala University; Uppsala Sweden
| | - C. Hellgren
- Department of Women's and Children's Health; Uppsala University; Uppsala Sweden
| | - Z. Jin
- Department of Neuroscience; Uppsala University; Uppsala Sweden
| | - E. B. Olafsson
- Department of Neuroscience; Uppsala University; Uppsala Sweden
- Department of Molecular Biosciences; Stockholm University; Stockholm Sweden
| | | | - B. Birnir
- Department of Neuroscience; Uppsala University; Uppsala Sweden
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Babateen O, Jin Z, Bhandage A, Korol SV, Westermark B, Forsberg Nilsson K, Uhrbom L, Smits A, Birnir B. Etomidate, propofol and diazepam potentiate GABA-evoked GABAA currents in a cell line derived from human glioblastoma. Eur J Pharmacol 2014; 748:101-7. [PMID: 25510230 DOI: 10.1016/j.ejphar.2014.12.001] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2014] [Revised: 12/01/2014] [Accepted: 12/04/2014] [Indexed: 12/15/2022]
Abstract
GABAA receptors are pentameric chloride ion channels that are opened by GABA. We have screened a cell line derived from human glioblastoma, U3047MG, for expression of GABAA receptor subunit isoforms and formation of functional ion channels. We identified GABAA receptors subunit α2, α3, α5, β1, β2, β3, δ, γ3, π, and θ mRNAs in the U3047MG cell line. Whole-cell GABA-activated currents were recorded and the half-maximal concentration (EC₅₀) for the GABA-activated current was 36 μM. The currents were activated by THIP (4,5,6,7-tetrahydroisoxazolo[5,4-c]pyridin-3-ol) and enhanced by the benzodiazepine diazepam (1 μM) and the general anesthetics etomidate and propofol (50 μM). In line with the expressed GABAA receptors containing at least the α3β3θ subunits, the receptors were highly sensitive to etomidate (EC₅₀=55 nM). Immunocytochemistry identified expression of the α3 and β3 subunit proteins. Our results show that the GABAA receptors in the glial cell line are functional and are modulated by classical GABAA receptor drugs. We propose that the U3047MG cell line may be used as a model system to study GABAA receptors function and pharmacology in glial cells.
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Affiliation(s)
- Omar Babateen
- Department of Neuroscience, Uppsala University, Uppsala, Sweden
| | - Zhe Jin
- Department of Neuroscience, Uppsala University, Uppsala, Sweden
| | - AmolK Bhandage
- Department of Neuroscience, Uppsala University, Uppsala, Sweden
| | - Sergiy V Korol
- Department of Neuroscience, Uppsala University, Uppsala, Sweden
| | - Bengt Westermark
- Department of Immunology, Genetic and Pathology, and Science for Life Laboratory, Uppsala University, Uppsala, Sweden
| | - Karin Forsberg Nilsson
- Department of Immunology, Genetic and Pathology, and Science for Life Laboratory, Uppsala University, Uppsala, Sweden
| | - Lene Uhrbom
- Department of Immunology, Genetic and Pathology, and Science for Life Laboratory, Uppsala University, Uppsala, Sweden
| | - Anja Smits
- Department of Neuroscience, Uppsala University, Uppsala, Sweden
| | - Bryndis Birnir
- Department of Neuroscience, Uppsala University, Uppsala, Sweden.
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Dysfunctional astrocytic and synaptic regulation of hypothalamic glutamatergic transmission in a mouse model of early-life adversity: relevance to neurosteroids and programming of the stress response. J Neurosci 2014; 33:19534-54. [PMID: 24336719 DOI: 10.1523/jneurosci.1337-13.2013] [Citation(s) in RCA: 113] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Adverse early-life experiences, such as poor maternal care, program an abnormal stress response that may involve an altered balance between excitatory and inhibitory signals. Here, we explored how early-life stress (ELS) affects excitatory and inhibitory transmission in corticotrophin-releasing factor (CRF)-expressing dorsal-medial (mpd) neurons of the neonatal mouse hypothalamus. We report that ELS associates with enhanced excitatory glutamatergic transmission that is manifested as an increased frequency of synaptic events and increased extrasynaptic conductance, with the latter associated with dysfunctional astrocytic regulation of glutamate levels. The neurosteroid 5α-pregnan-3α-ol-20-one (5α3α-THPROG) is an endogenous, positive modulator of GABAA receptors (GABAARs) that is abundant during brain development and rises rapidly during acute stress, thereby enhancing inhibition to curtail stress-induced activation of the hypothalamic-pituitary-adrenocortical axis. In control mpd neurons, 5α3α-THPROG potently suppressed neuronal discharge, but this action was greatly compromised by prior ELS exposure. This neurosteroid insensitivity did not primarily result from perturbations of GABAergic inhibition, but rather arose functionally from the increased excitatory drive onto mpd neurons. Previous reports indicated that mice (dams) lacking the GABAAR δ subunit (δ(0/0)) exhibit altered maternal behavior. Intriguingly, δ(0/0) offspring showed some hallmarks of abnormal maternal care that were further exacerbated by ELS. Moreover, in common with ELS, mpd neurons of δ(0/0) pups exhibited increased synaptic and extrasynaptic glutamatergic transmission and consequently a blunted neurosteroid suppression of neuronal firing. This study reveals that increased synaptic and tonic glutamatergic transmission may be a common maladaptation to ELS, leading to enhanced excitation of CRF-releasing neurons, and identifies neurosteroids as putative early regulators of the stress neurocircuitry.
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18
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Hill M, Pašková A, Kančeva R, Velíková M, Kubátová J, Kancheva L, Adamcová K, Mikešová M, Žižka Z, Koucký M, Šarapatková H, Kačer V, Matucha P, Meloun M, Pařízek A. Steroid profiling in pregnancy: a focus on the human fetus. J Steroid Biochem Mol Biol 2014; 139:201-22. [PMID: 23583279 DOI: 10.1016/j.jsbmb.2013.03.008] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/02/2012] [Revised: 03/24/2013] [Accepted: 03/26/2013] [Indexed: 12/12/2022]
Abstract
In this review we focused on steroid metabolomics in human fetuses and newborns and its role in the physiology and pathophysiology of human pregnancy and subsequent stages of human life, and on the physiological relevance of steroids influencing the nervous systems with regards to their concentrations in the fetus. Steroid profiling provides valuable data for the diagnostics of diseases related to altered steroidogenesis in the fetal and maternal compartments and placenta. We outlined a potential use of steroid metabolomics for the prediction of reproductive disorders, misbalance of hypothalamic-pituitary-adrenal axis, and impaired insulin sensitivity in subsequent stages of human life. A possible role of steroids exhibiting a non-genomic effect in the development of gestational diabetes and in the neuroprotection via negative modulation of AMPA/kainate receptors was also indicated. Increasing progesterone synthesis and catabolism, declining production of tocolytic 5β-pregnane steroids, and rising activities of steroid sulfotransferases with the approaching term may be of importance in sustaining pregnancy. An increasing trend was demonstrated with advancing gestation toward the production of ketones (and 3β-hydroxyl groups in the case of 3α-hydroxy-steroids) was demonstrated in the fetus on the expense of 3α-hydroxy-, 17β-hydroxy-, and 20α-hydroxy-groups weakening in the sequence C17, C3, and C20. There was higher production of active progestogen but lower production of active estrogen and GABAergic steroids with the approaching term. Rising activities of placental CYP19A1 and oxidative isoforms of HSD17B, and of fetal CYP3A7 with advancing gestation may protect the fetus from hyperestrogenization. This article is part of a Special Issue entitled 'Pregnancy and Steroids'.
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Affiliation(s)
- Martin Hill
- Institute of Endocrinology, Národní třída 8, Prague CZ 116 94, Czech Republic.
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Chesnoy-Marchais D. Bicuculline- and neurosteroid-sensitive tonic chloride current in rat hypoglossal motoneurons and atypical dual effect of SR95531. Eur J Neurosci 2012. [PMID: 23190086 DOI: 10.1111/ejn.12074] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Hypoglossal motoneurons (HMs) are known to be under 'permanent' bicuculline-sensitive inhibition and to show 'transient' synaptic γ-aminobutyric acid (GABA)(A) and glycine inhibitory responses. The present paper describes a permanent bicuculline-sensitive current that should contribute to their tonic inhibition. This current was recorded in brainstem slices superfused without any exogenous agonist and remained detectable with tetrodotoxin. It could also be blocked by the other GABA(A) antagonists picrotoxin (PTX) and 2-(3-carboxypropyl)-3-amino-6-(4 methoxyphenyl)pyridazinium bromide) (SR95531; gabazine), but persisted in the presence of a specific blocker of α5-containing GABA(A) receptors. Addition of 2 μm 4,5,6,7-tetrahydroisoxazolo[5,4-c]pyridin-3-ol hydrochloride (THIP), known to preferentially activate GABA(A) receptors devoid of a γ-subunit, induced a sustained anionic current that could be further enhanced by neurosteroids such as allopregnanolone (100 nm). Thus, HMs show a tonic inhibitory current carried by extrasynaptic γ-free GABA(A) receptors, highly sensitive to neurosteroids. A second result was obtained by using SR95531 at concentrations sufficiently high to rapidly block the tonic current above the chloride equilibrium potential (E(C) (l)). Surprisingly, below E(C) (l) , SR95531 (10-40 μm) activated a sustained inward current, associated with a conductance increase, and resistant to bicuculline or PTX (100 μm). Similarly, after blockade of the bicuculline-sensitive current, SR95531 activated an outward current above E(C) (l). The bicuculline-resistant anionic current activated by SR95531 could be blocked by a GABA(C) receptor antagonist. Thus, two types of inhibitory GABA receptors, belonging to the GABA(A) and GABA(C) families, are able to show a sustained activity in HMs and provide promising targets for neuroprotection under overexcitatory situations known to easily damage these particularly fragile neurons.
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Affiliation(s)
- Dominique Chesnoy-Marchais
- UMR788 INSERM et Université Paris-Sud, Bátiment Grégory Pincus, 80 rue du Général Leclerc, 94276 Le Kremlin-Bicětre Cedex, France.
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20
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Yousaf MZ, Zia S, Babar ME, Ashfaq UA. The epidemic of HIV/AIDS in developing countries; the current scenario in Pakistan. Virol J 2011; 8:401. [PMID: 21838892 PMCID: PMC3173394 DOI: 10.1186/1743-422x-8-401] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2011] [Accepted: 08/12/2011] [Indexed: 11/15/2022] Open
Abstract
HIV (Human Immunodeficiency virus) causes (acquired immunodeficiency syndrome) AIDS, in which the immune system of body totally fails to develop any defense against the foreign invaders. Infection with HIV occurs by transfer of blood, semen, and breast milk. HIV/AIDS is a global problem and it results nearly 25 million deaths worldwide. Developing countries like Pakistan have issues regarding Public Health. Currently, epidemic of HIV/AIDS is established in Pakistan and there is a threat of an expanded HIV/AIDS outbreak in the country. The major reason is that population is engaging in high-risk practices, low awareness about HIV/AIDS, and treacherous blood transfusion practices. A supplementary threat to Pakistan is India because both sharing a border and India is facing a rapidly growing HIV/AIDS epidemic. Local NGOs, National and International organizations are warning that in near future Pakistan may experiences bad situation regarding HIV/AIDS.In the present article we focused current situation of surveillance of HIV/AIDS, its virology, genotype, diagnostics, high-risk groups, reasons of vulnerability in Pakistani population, and the role of different national and international organizations in this situation.
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Affiliation(s)
- Muhammad Z Yousaf
- Institute of Biochemistry and Biotechnology University of Veterinary and Animal Sciences, Lahore
| | - Sadia Zia
- Institute of Biochemistry and Biotechnology University of Veterinary and Animal Sciences, Lahore
| | - Masroor E Babar
- Institute of Biochemistry and Biotechnology University of Veterinary and Animal Sciences, Lahore
| | - Usman A Ashfaq
- Division of Molecular Medicine, National Centre of Excellence in Molecular Biology, University of the Punjab, Lahore, Pakistan
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21
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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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22
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Liao IH, Corbett BA, Gilbert DL, Bunge SA, Sharp FR. Blood gene expression correlated with tic severity in medicated and unmedicated patients with Tourette Syndrome. Pharmacogenomics 2011; 11:1733-41. [PMID: 21142917 DOI: 10.2217/pgs.10.160] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
BACKGROUND Tourette Syndrome (TS) has been linked to both genetic and environmental factors. Gene-expression studies provide valuable insight into the causes of TS; however, many studies of gene expression in TS do not account for the effects of medication. MATERIALS & METHODS To investigate the effects of medication on gene expression in TS patients, RNA was isolated from the peripheral blood of 20 medicated TS subjects (MED) and 23 unmedicated TS subjects (UNMED), and quantified using whole-genome Affymetrix microarrays. RESULTS D2 dopamine receptor expression correlated positively with tic severity in MED but not UNMED. GABA(A) receptor ε subunit expression negatively correlated with tic severity in UNMED but not MED. Phenylethanolamine N-methyltransferase expression positively correlated with tic severity in UNMED but not MED. CONCLUSION Modulation of tics by TS medication is associated with changes in dopamine, norepinephrine and GABA pathways.
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23
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Inhibition of apoptotic signalling in spermine-treated vascular smooth muscle cells by a novel glutathione precursor. Cell Biol Int 2010; 34:503-11. [PMID: 20121705 DOI: 10.1042/cbi20090349] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
CKD (chronic kidney disease) is a public health problem, mediated by haemodynamic and non-haemodynamic events including oxidative stress. We investigated the effect of two GSH (glutathione) precursors, NAC (N-acetylcysteine) and cystine as the physiological carrier of cysteine in GSH with added selenomethionine (F1) in preventing spermine (uraemic toxin)-induced apoptosis in cultured human aortic VSMC (vascular smooth muscle cells). VSMCs exposed to spermine (15 microM) with or without antioxidants (doses 50, 100, 200 and 500 microg/ml) were assessed for apoptosis, JNK (c-Jun-NH2-terminal kinase) activation and iNOS (inducible nitric oxide synthase) induction and activation of intrinsic pathway signalling. Spermine exposure resulted in activation of JNK and iNOS induction and apoptosis. NAC and F1 (dose range 50-500 microg/ml) attenuated spermine-induced acceleration of VSMC apoptosis but only F1 (at 200 and 500 microg/ml) maintained spermine-induced apoptosis at control levels. Spermine-induced JNK activation was prevented by 200 microg/ml of both NAC and F1, while iNOS induction was blocked only by F1. Notably, the adverse effects of spermine on BAX/BCL-2 ratio, cytochrome c release and caspase activation was fully attenuated by F1. In conclusion, F1 was more effective than NAC in preventing spermine-induced apoptosis and downstream changes in related signal transduction pathways in VSMCs. Further studies are needed to examine the effect of these compounds in preventing CKD-associated vascular disease.
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Uusi-Oukari M, Korpi ER. Regulation of GABA(A) receptor subunit expression by pharmacological agents. Pharmacol Rev 2010; 62:97-135. [PMID: 20123953 DOI: 10.1124/pr.109.002063] [Citation(s) in RCA: 152] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
The gamma-aminobutyric acid (GABA) type A receptor system, the main fast-acting inhibitory neurotransmitter system in the brain, is the pharmacological target for many drugs used clinically to treat, for example, anxiety disorders and epilepsy, and to induce and maintain sedation, sleep, and anesthesia. These drugs facilitate the function of pentameric GABA(A) receptors that exhibit widespread expression in all brain regions and large structural and pharmacological heterogeneity as a result of composition from a repertoire of 19 subunit variants. One of the main problems in clinical use of GABA(A) receptor agonists is the development of tolerance. Most drugs, in long-term use and during withdrawal, have been associated with important modulations of the receptor subunit expression in brain-region-specific manner, participating in the mechanisms of tolerance and dependence. In most cases, the molecular mechanisms of regulation of subunit expression are poorly known, partly as a result of neurobiological adaptation to altered neuronal function. More knowledge has been obtained on the mechanisms of GABA(A) receptor trafficking and cell surface expression and the processes that may contribute to tolerance, although their possible pharmacological regulation is not known. Drug development for neuropsychiatric disorders, including epilepsy, alcoholism, schizophrenia, and anxiety, has been ongoing for several years. One key step to extend drug development related to GABA(A) receptors is likely to require deeper understanding of the adaptational mechanisms of neurons, receptors themselves with interacting proteins, and finally receptor subunits during drug action and in neuropsychiatric disease processes.
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Affiliation(s)
- Mikko Uusi-Oukari
- Department of Pharmacology, Drug Development and Therapeutics, University of Turku, Itainen Pitkakatu 4, 20014 Turku, Finland.
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Sasaki K, Matsuo M, Maeda T, Zaitsu M, Hamasaki Y. Febrile seizures: characterization of double-stranded RNA-induced gene expression. Pediatr Neurol 2009; 41:114-8. [PMID: 19589459 DOI: 10.1016/j.pediatrneurol.2009.03.003] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/01/2008] [Revised: 02/23/2009] [Accepted: 03/04/2009] [Indexed: 11/29/2022]
Abstract
An association has long been suspected between febrile seizures and interleukin-1beta, the most potent endogenous pyrogen. Interleukin-1beta production increases after double-stranded RNA stimulation in leukocytes of febrile seizure patients. To elucidate the genetics of the immune response, the gene expression pattern after double-stranded RNA stimulation was investigated using DNA microarray. Compared with the control group, expression of the genes ACCN4 (sodium channel), KCNC3 (potassium channel), GABRE (gamma-aminobutyric acid receptor epsilon subunit), RIPK2 (receptor interacting protein kinase-2), TLR4 (toll-like receptor-4), IL26 (interleukin-26), and TNF (tumor necrosis factor), and CASP1 (caspase-1) was increased in the febrile seizure group (P < 0.01). Because RIPK2 and CASP1 are associated with interleukin-1beta production, increased expression might cause increased interleukin-1beta production in the febrile seizure patients. The induced expression of several ion channel genes by double-stranded RNA may affect neuronal excitability which leads to seizure susceptibility during infection.
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Affiliation(s)
- Kazuya Sasaki
- Department of Pediatrics, Faculty of Medicine, Saga University, Saga, Japan
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26
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Belujon P, Baufreton J, Grandoso L, Boué-Grabot E, Batten TFC, Ugedo L, Garret M, Taupignon AI. Inhibitory transmission in locus coeruleus neurons expressing GABAA receptor epsilon subunit has a number of unique properties. J Neurophysiol 2009; 102:2312-25. [PMID: 19625540 DOI: 10.1152/jn.00227.2009] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Fast inhibitory synaptic transmission in the brain relies on ionotropic GABA(A) receptors (GABA(A)R). Eighteen genes code for GABA(A)R subunits, but little is known about the epsilon subunit. Our aim was to identify the synaptic transmission properties displayed by native receptors incorporating epsilon. Immunogold localization detected epsilon at synaptic sites on locus coeruleus (LC) neurons. In situ hybridization revealed prominent signals from epsilon, and mRNAs, some low beta1 and beta3 signals, and no gamma signal. Using in vivo extracellular and in vitro patch-clamp recordings in LC, we established that neuron firing rates, GABA-activated currents, and mIPSC charge were insensitive to the benzodiazepine flunitrazepam (FLU), in agreement with the characteristics of recombinant receptors including an epsilon subunit. Surprisingly, LC provided binding sites for benzodiazepines, and GABA-induced currents were potentiated by diazepam (DZP) in the micromolar range. A number of GABA(A)R ligands significantly potentiated GABA-induced currents, and zinc ions were only active at concentrations above 1 muM, further indicating that receptors were not composed of only alpha and beta subunits, but included an epsilon subunit. In contrast to recombinant receptors including an epsilon subunit, GABA(A)R in LC showed no agonist-independent opening. Finally, we determined that mIPSCs, as well as ensemble currents induced by ultra-fast GABA application, exhibited surprisingly slow rise times. Our work thus defines the signature of native GABA(A)R with a subunit composition including epsilon: differential sensitivity to FLU and DZP and slow rise time of currents. We further propose that alpha(3,) beta(1/3,) and epsilon subunits compose GABA(A)R in LC.
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Affiliation(s)
- P Belujon
- University Bordeaux, Centre National de la Recherche Scientifique Unité Mixte de Recherche, Bordeaux, France
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Silva JFD, Bidinotto LT, Furtado KS, Salvadori DMF, Rivelli DP, Barros SBDM, Rodrigues MAM, Barbisan LF. Maté attenuates DNA damage and carcinogenesis induced by diethylnitrosamine and thermal injury in rat esophagus. Food Chem Toxicol 2009; 47:1521-9. [DOI: 10.1016/j.fct.2009.03.040] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2008] [Revised: 03/18/2009] [Accepted: 03/28/2009] [Indexed: 11/26/2022]
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Nimmich ML, Heidelberg LS, Fisher JL. RNA editing of the GABA(A) receptor alpha3 subunit alters the functional properties of recombinant receptors. Neurosci Res 2009; 63:288-93. [PMID: 19367790 DOI: 10.1016/j.neures.2009.01.003] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
RNA editing provides a post-transcriptional mechanism to increase structural heterogeneity of gene products. Recently, the alpha3 subunit of the GABAA receptors has been shown to undergo RNA editing. As a result, a highly conserved isoleucine residue in the third transmembrane domain is replaced with a methionine. To determine the effect of this structural change on receptor function, we compared the GABA sensitivity, pharmacological properties and macroscopic kinetics of recombinant receptors containing either the edited or unedited forms of the alpha3 subunit along with beta3 and gamma2L. Editing substantially altered the GABA sensitivity and deactivation rate of the receptors, with the unedited form showing a lower GABA EC50 and slower decay. Comparable effects were observed with a mutation at the homologous location in the alpha1 subunit, suggesting a common role for this site in regulation of channel gating. Except for the response to GABA, the pharmacological properties of the receptor were unaffected by editing, with similar enhancement by a variety of modulators. Since RNA editing of the alpha3 subunit increases through development, our findings suggest that GABAergic neurotransmission may be more effective early in development, with greater GABA sensitivity and slower decay rates conferred by the unedited alpha3 subunit.
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Affiliation(s)
- Mitchell L Nimmich
- Department of Pharmacology, Physiology and Neuroscience, University of South Carolina School of Medicine, Columbia 29208, USA
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Abstract
Most sedative-hypnotics used in insomnia treatment target the gamma-aminobutyric acid (GABA)(A) receptors. A vast repertoire of GABA(A) receptor subtypes has been identified and displays specific electrophysiological and functional properties. GABA(A)-mediated inhibition traditionally refers to 'phasic' inhibition, arising from synaptic GABA(A) receptors which transiently inhibit neurons. However, there is growing evidence that peri- or extra-synaptic GABA(A) receptors are continuously activated by low GABA concentrations and mediate a 'tonic' conductance. This slower type of signaling appears to play a key role in controlling cell excitability. This review aims at summarizing recent knowledge on GABA transmission, including the emergence of tonic conductance, and highlighting the importance of GABA(A) receptor heterogeneity. The mechanism of action of sedative-hypnotic drugs and their effects on sleep and the electroencephalogram will be reported. Furthermore, studies using genetically engineered mice will be emphasized, providing insights into the role of GABA(A) receptors in mechanisms underlying physiological and pharmacological sleep. Finally, we will address the potential of GABA(A) receptor pharmacology for the treatment of insomnia.
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Affiliation(s)
- Raphaëlle Winsky-Sommerer
- Section for Chronobiology and Sleep Research, Institute of Pharmacology and Toxicology, University of Zurich, Zurich, Switzerland.
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Pape JR, Bertrand SS, Lafon P, Odessa MF, Chaigniau M, Stiles JK, Garret M. Expression of GABA(A) receptor alpha3-, theta-, and epsilon-subunit mRNAs during rat CNS development and immunolocalization of the epsilon subunit in developing postnatal spinal cord. Neuroscience 2009; 160:85-96. [PMID: 19249336 DOI: 10.1016/j.neuroscience.2009.02.043] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2008] [Revised: 02/03/2009] [Accepted: 02/19/2009] [Indexed: 12/13/2022]
Abstract
Ionotropic GABA(A) receptors are heteromeric structures composed of a combination of five from at least 16 different subunits. Subunit genes are expressed in distinct cell types at specific times during development. The most abundant native GABA(A) receptors consist of alpha1-, beta2-, and gamma2-subunits that are co-expressed in numerous brain areas. alpha3-, theta-, And epsilon-subunits are clustered on the X chromosome and show striking overlapping expression patterns throughout the adult rat brain. To establish whether these subunits are temporally and spatially co-expressed, we used in situ hybridization to analyze their expression throughout rat development from embryonic stage E14 to postnatal stage P12. Each transcript exhibited a unique or a shared regional and temporal developmental expression profile. The thalamic expression pattern evolved from a restricted expression of epsilon and theta transcripts before birth, to a theta and alpha3 expression at birth, and finally to a grouped epsilon, theta and alpha3 expression postpartum. However, strong similarities occurred, such as a grouped expression of the three subunits within the hypothalamus, tegmentum and pontine nuclei throughout the developmental process. At early stages of development (E17), epsilon and theta appeared to have a greater spatial distribution before the dominance of the alpha3 subunit transcript around birth. We also revealed expression of alpha3, theta, and epsilon in the developing spinal cord and identified neurons that express epsilon in the postnatal dorsal horn, intermediolateral column and motoneurons. Our findings suggest that various combinations of alpha3-, theta- and epsilon-subunits may be assembled at a regional and developmental level in the brain.
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Affiliation(s)
- J-R Pape
- Université de Bordeaux, CNRS, UMR 5228, France
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Intraobserver and interobserver variability in distinguishing between endocervical and endometrial adenocarcinoma on problematic cases of cervical curettings. Int J Gynecol Pathol 2008; 27:431-6. [PMID: 18580323 DOI: 10.1097/pgp.0b013e3181601792] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
We conducted a prospective study where 4 pathologists examined patients' problematic cases of cervical curetting for adenocarcinoma to determine whether it is of endocervical or endometrial origin based on 3 parameters: age, morphology, and immunohistochemistry (IHC) panel. Our aims were to evaluate the intraobserver and interobserver variability and to compare the results using those parameters to the final hysterectomy specimens. The value of morphology, morphology+age, and the combined parameters (morphology+age+IHC) in predicting the correct origin of the tumor was evaluated. The intraobserver agreements ranged from fair to almost perfect for each of morphology, morphology+age, and the combined parameters. The interobserver agreements were fair in the first review and ranged from slight to fair in the second review. The agreements between the diagnosis based on morphology, morphology+age, and the combined parameters compared with the final diagnosis on the hysterectomy specimen were slight (kappa=0.137), fair (kappa=0.290), and moderate (kappa=0.497), respectively. We concluded that (i) discriminating between endocervical and endometrial carcinoma is highly subject to intraobserver and interobserver variability. (ii) Surprisingly, this variability is not affected by pathologists' experience. (iii) An IHC panel adds a useful piece of information to predict the tumor origin. Lastly, even though the combination of morphology, age, and IHC is far from perfect in predicting the correct origin of the tumor, it is still the best available method.
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Fisher JL. The anti-convulsant stiripentol acts directly on the GABA(A) receptor as a positive allosteric modulator. Neuropharmacology 2008; 56:190-7. [PMID: 18585399 DOI: 10.1016/j.neuropharm.2008.06.004] [Citation(s) in RCA: 87] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2008] [Revised: 05/26/2008] [Accepted: 06/04/2008] [Indexed: 01/13/2023]
Abstract
Stiripentol (STP) has been used as co-therapy for treatment of epilepsy for many years. Its mechanism of action has long been considered to be indirect, as it inhibits the enzymes responsible for metabolism of other anti-convulsant agents. However, a recent report suggested that STP might also act at the neuronal level, increasing inhibitory GABAergic neurotransmission. We examined the effect of STP on the functional properties of recombinant GABA(A) receptors (GABARs) and found that it was a positive allosteric modulator of these ion channels. Its activity showed some dependence on subunit composition, with greater potentiation of alpha3-containing receptors and reduced potentiation when the beta1 or epsilon subunits were present. STP caused a leftward shift in the GABA concentration-response relationship, but did not increase the peak response of the receptors to a maximal GABA concentration. Although STP shares some functional characteristics with the neurosteroids, its activity was not inhibited by a neurosteroid site antagonist and was unaffected by a mutation in the alpha3 subunit that reduced positive modulation by neurosteroids. The differential effect of STP on beta1- and beta2/beta3-containing receptors was not altered by mutations within the second transmembrane domain that affect modulation by loreclezole. These findings suggest that STP acts as a direct allosteric modulator of the GABAR at a site distinct from many commonly used anti-convulsant, sedative and anxiolytic drugs. Its higher activity at alpha3-containing receptors as well as its activity at delta-containing receptors may provide a unique opportunity to target selected populations of GABARs.
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Affiliation(s)
- Janet L Fisher
- Department of Pharmacology, Physiology and Neuroscience, University of South Carolina School of Medicine, Columbia, SC 29208, USA.
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Winsky-Sommerer R, Knapman A, Fedele DE, Schofield CM, Vyazovskiy VV, Rudolph U, Huguenard JR, Fritschy JM, Tobler I. Normal sleep homeostasis and lack of epilepsy phenotype in GABA A receptor alpha3 subunit-knockout mice. Neuroscience 2008; 154:595-605. [PMID: 18485607 DOI: 10.1016/j.neuroscience.2008.03.081] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2008] [Revised: 03/27/2008] [Accepted: 03/27/2008] [Indexed: 11/17/2022]
Abstract
Thalamo-cortical networks generate specific patterns of oscillations during distinct vigilance states and epilepsy, well characterized by electroencephalography (EEG). Oscillations depend on recurrent synaptic loops, which are controlled by GABAergic transmission. In particular, GABA A receptors containing the alpha3 subunit are expressed predominantly in cortical layer VI and thalamic reticular nucleus (nRT) and regulate the activity and firing pattern of neurons in relay nuclei. Therefore, ablation of these receptors by gene targeting might profoundly affect thalamo-cortical oscillations. Here, we investigated the role of alpha3-GABA A receptors in regulating vigilance states and seizure activity by analyzing chronic EEG recordings in alpha3 subunit-knockout (alpha3-KO) mice. The presence of postsynaptic alpha3-GABA A receptors/gephyrin clusters in the nRT and GABA A-mediated synaptic currents in acute thalamic slices was also examined. EEG spectral analysis showed no difference between genotypes during non rapid-eye movement (NREM) sleep or at waking-NREM sleep transitions. EEG power in the spindle frequency range (10-15 Hz) was significantly lower at NREM-REM sleep transitions in mutant compared with wild-type mice. Enhancement of sleep pressure by 6 h sleep deprivation did not reveal any differences in the regulation of EEG activities between genotypes. Finally, the waking EEG showed a slightly larger power in the 11-13-Hz band in alpha3-KO mice. However, neither behavior nor the waking EEG showed alterations suggestive of absence seizures. Furthermore, alpha3-KO mice did not differ in seizure susceptibility in a model of temporal lobe epilepsy. Strikingly, despite the disruption of postsynaptic gephyrin clusters, whole-cell patch clamp recordings revealed intact inhibitory synaptic transmission in the nRT of alpha3-KO mice. These findings show that the lack of alpha3-GABA(A) receptors is extensively compensated for to preserve the integrity of thalamo-cortical function in physiological and pathophysiological situations.
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Affiliation(s)
- R Winsky-Sommerer
- Institute of Pharmacology and Toxicology, University of Zurich, Winterthurerstrasse 190, Zurich, Switzerland
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The promiscuous role of the epsilon subunit in GABAA receptor biogenesis. Mol Cell Neurosci 2008; 37:610-21. [DOI: 10.1016/j.mcn.2007.12.011] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2007] [Revised: 11/21/2007] [Accepted: 12/06/2007] [Indexed: 11/18/2022] Open
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Dibble SL, Eliason MJ, Christiansen MA. Chronic Illness Care for Lesbian, Gay, & Bisexual Individuals. Nurs Clin North Am 2007; 42:655-74; viii. [DOI: 10.1016/j.cnur.2007.08.002] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Martyniuk CJ, Aris-Brosou S, Drouin G, Cahn J, Trudeau VL. Early evolution of ionotropic GABA receptors and selective regimes acting on the mammalian-specific theta and epsilon subunits. PLoS One 2007; 2:e894. [PMID: 17878929 PMCID: PMC1975676 DOI: 10.1371/journal.pone.0000894] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2007] [Accepted: 08/14/2007] [Indexed: 11/26/2022] Open
Abstract
Background The amino acid neurotransmitter GABA is abundant in the central nervous system (CNS) of both invertebrates and vertebrates. Receptors of this neurotransmitter play a key role in important processes such as learning and memory. Yet, little is known about the mode and tempo of evolution of the receptors of this neurotransmitter. Here, we investigate the phylogenetic relationships of GABA receptor subunits across the chordates and detail their mode of evolution among mammals. Principal Findings Our analyses support two major monophyletic clades: one clade containing GABAA receptor α, γ, and ε subunits, and another one containing GABAA receptor ρ, β, δ, θ, and π subunits. The presence of GABA receptor subunits from each of the major clades in the Ciona intestinalis genome suggests that these ancestral duplication events occurred before the divergence of urochordates. However, while gene divergence proceeded at similar rates on most receptor subunits, we show that the mammalian-specific subunits θ and ε experienced an episode of positive selection and of relaxed constraints, respectively, after the duplication event. Sites putatively under positive selection are placed on a three-dimensional model obtained by homology-modeling. Conclusions Our results suggest an early divergence of the GABA receptor subunits, before the split from urochordates. We show that functional changes occurred in the lineages leading to the mammalian-specific subunit θ, and we identify the amino acid sites putatively responsible for the functional divergence. We discuss potential consequences for the evolution of mammals and of their CNS.
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Affiliation(s)
- Christopher J. Martyniuk
- Department of Biology and Centre for Advanced Research in Environmental Genomics, University of Ottawa, Ottawa, Ontario, Canada
| | - Stéphane Aris-Brosou
- Department of Biology and Centre for Advanced Research in Environmental Genomics, University of Ottawa, Ottawa, Ontario, Canada
- Department of Mathematics and Statistics, University of Ottawa, Ottawa, Ontario, Canada
- * To whom correspondence should be addressed. E-mail:
| | - Guy Drouin
- Department of Biology and Centre for Advanced Research in Environmental Genomics, University of Ottawa, Ottawa, Ontario, Canada
| | - Joel Cahn
- Department of Biology and Centre for Advanced Research in Environmental Genomics, University of Ottawa, Ottawa, Ontario, Canada
| | - Vance L. Trudeau
- Department of Biology and Centre for Advanced Research in Environmental Genomics, University of Ottawa, Ottawa, Ontario, Canada
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Wang JF, Wei DQ, Li L, Zheng SY, Li YX, Chou KC. 3D structure modeling of cytochrome P450 2C19 and its implication for personalized drug design. Biochem Biophys Res Commun 2007; 355:513-9. [PMID: 17307149 DOI: 10.1016/j.bbrc.2007.01.185] [Citation(s) in RCA: 88] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2007] [Accepted: 01/31/2007] [Indexed: 11/15/2022]
Abstract
Cytochrome P450 2C19 (CYP2C19) is a member of the cytochrome P-450 enzyme superfamily and plays an important role in the metabolism of drugs. In order to gain insights for developing personalized drugs, the 3D (dimensional) structure of CYP2C19 has been developed based on the crystal structure of CYP2C9 (PDB code 1R90), and its structure-activity relationship with the ligands of CEC, Fluvoxamine, Lescol, and Ticlopidine investigated through the structure-activity relationship approach. By means of a series of docking studies, the binding pockets of CYP2C19 for the four compounds are explicitly defined that will be very useful for conducting mutagenesis studies, providing insights into personalization of drug treatments and stimulating novel strategies for finding desired personalized drugs.
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Affiliation(s)
- Jing-Fang Wang
- College of Life Science and Biotechnology, Shanghai Jiaotong University, Shanghai 200240, China
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38
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Li C, Carlier PR, Ren H, Kan KKW, Hui K, Wang H, Li W, Li Z, Xiong K, Clement EC, Xue H, Liu X, Li M, Pang Y, Han Y. Alkylene tether-length dependent γ-aminobutyric acid type A receptor competitive antagonism by tacrine dimers. Neuropharmacology 2007; 52:436-43. [PMID: 17056074 DOI: 10.1016/j.neuropharm.2006.07.039] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2006] [Revised: 07/24/2006] [Accepted: 07/26/2006] [Indexed: 11/16/2022]
Abstract
Bis(7)-tacrine was previously demonstrated as an antagonist of gamma-aminobutyric acid type A (GABA(A)) receptors. In this study, the effects of a series of alkylene-linked tacrine dimers on GABA(A) receptors were examined. In radioligand binding assay, the analogues differed in binding affinity for GABA(A) receptors, and potency monotonically increased as the tether was shortened from nine to two methylenes. Bis(2)-tacrine, the shortest tacrine dimer, could displace [(3)H]muscimol from rat brain membranes with an IC(50) of 0.48 microM, which was 11, 13 and 525 times more potent than the GABA(A) receptor antagonist (+)-bicuculline, bis(7)-tacrine and tacrine, respectively. In whole-cell patch-clamp recordings, these dimeric tacrine analogues competitively antagonized GABA-induced inward current with a rank order of potency of bis(2)-tacrine>bicuculline>bis(7)-tacrine>bis(9)-tacrine>tacrine, and the potency of bis(2)-tacrine was 11, 18 and 487 times higher than that of (+)-bicuculline, bis(7)-tacrine and tacrine, respectively. Bis(2)-tacrine shifted the GABA concentration-response curve to the right in a parallel manner, and the inhibition was voltage-independent between -80 and +20 mV. It can be concluded that the shorter the alkylene linkage in tacrine dimers the stronger the binding affinity and higher the antagonistic effect on the GABA(A) receptor will be.
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Affiliation(s)
- Chaoying Li
- Laboratory of Molecular and Cellular Neurobiology, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, MD 20892, USA
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Farrant M, Kaila K. The cellular, molecular and ionic basis of GABA(A) receptor signalling. PROGRESS IN BRAIN RESEARCH 2007; 160:59-87. [PMID: 17499109 DOI: 10.1016/s0079-6123(06)60005-8] [Citation(s) in RCA: 266] [Impact Index Per Article: 15.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
GABA(A) receptors mediate fast synaptic inhibition in the CNS. Whilst this is undoubtedly true, it is a gross oversimplification of their actions. The receptors themselves are diverse, being formed from a variety of subunits, each with a different temporal and spatial pattern of expression. This diversity is reflected in differences in subcellular targetting and in the subtleties of their response to GABA. While activation of the receptors leads to an inevitable increase in membrane conductance, the voltage response is dictated by the distribution of the permeant Cl(-) and HCO(3)(-) ions, which is established by anion transporters. Similar to GABA(A) receptors, the expression of these transporters is not only developmentally regulated but shows cell-specific and subcellular variation. Untangling all these complexities allows us to appreciate the variety of GABA-mediated signalling, a diverse set of phenomena encompassing both synaptic and non-synaptic functions that can be overtly excitatory as well as inhibitory.
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Affiliation(s)
- Mark Farrant
- Department of Pharmacology, UCL (University College London), Gower Street, London WC1E 6BT, UK.
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Groves JO, Guscott MR, Hallett DJ, Rosahl TW, Pike A, Davies A, Wafford KA, Reynolds DS. The role of GABAAβ2 subunit-containing receptors in mediating the anticonvulsant and sedative effects of loreclezole. Eur J Neurosci 2006; 24:167-74. [PMID: 16882014 DOI: 10.1111/j.1460-9568.2006.04890.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The majority of inhibitory neurotransmission in the brain is mediated by the gamma-aminobutyric acid (GABA) type A (GABA(A)) receptor. The anticonvulsant loreclezole largely acts by potentiating GABA(A) receptors containing beta2 and beta3 subunits. We used a genetically modified mouse containing a loreclezole-insensitive beta2 subunit (beta2N265S) to determine the role of this subunit in mediating the sedative and anticonvulsive effects of loreclezole. Sedation was assessed by measuring spontaneous locomotor activity and beam walking performance, and anticonvulsant efficacy was determined by pentylenetetrazole (PTZ) and amygdala kindling-induced seizures. The beta2N265S mice did not exhibit loreclezole-mediated sedation as shown by normal locomotor activity and beam walking performance. However, loreclezole also failed to provide significant protection against PTZ-induced seizures in the beta2N265S mice. Reduced efficacy against amygdala-kindled seizures, both acutely and over a 13-day chronic dosing study, was also observed in beta2N265S mice. These results suggest that the majority of the sedative effects and a significant proportion of the anticonvulsant efficacy of loreclezole are mediated via beta2-containing GABA(A) receptors.
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Affiliation(s)
- James O Groves
- Merck, Sharp and Dohme Research Laboratories, Neuroscience Research Centre, Terlings Park, Eastwick Road, Harlow, Essex CM20 2QR, UK.
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Thompson AJ, Padgett CL, Lummis SCR. Mutagenesis and molecular modeling reveal the importance of the 5-HT3 receptor F-loop. J Biol Chem 2006; 281:16576-82. [PMID: 16595668 DOI: 10.1074/jbc.m601265200] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The 5-HT(3) receptor is a member of the Cys-loop family of ligand-gated ion channels. The extracellular domains of these proteins contain six amino acid loops (A-F) that converge to form the ligand binding site. In this study we have mutated 21 residues in or close to the 5-HT(3) receptor F-loop (Ile(192) to Gly(212)) to Ala or to a residue with similar chemical properties. Mutant receptors were expressed in HEK293 cells, and binding affinity was measured using [(3)H]granisetron. Two regions displayed decreases in binding affinity when mutated to Ala (Ile(192)-Arg(196) and Asp(204)-Ser(206)), but only one region was sensitive when mutated to chemically similar residues (Ile(192)-Val(201)). Homology modeling using acetylcholine-binding protein crystal structures with a variety of different bound ligands suggests there may be distinct movements of Trp(195) and Asp(204) upon ligand binding, indicating that these residues and their immediate neighbors have the ability to interact differently with different ligands. The models suggest predominantly lateral movement around Asp(204) and rotational movement around Trp(195), indicating the former is in a more flexible region. Overall our results are consistent with a flexible 5-HT(3) receptor F-loop with two regions that have specific but distinct roles in ligand binding.
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Affiliation(s)
- Andrew J Thompson
- Department of Biochemistry, University of Cambridge, Cambridge CB2 1QW, UK
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