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Bhagat K, Singh JV, Pagare PP, Kumar N, Sharma A, Kaur G, Kinarivala N, Gandu S, Singh H, Sharma S, Bedi PMS. Rational approaches for the design of various GABA modulators and their clinical progression. Mol Divers 2021; 25:551-601. [PMID: 32170466 PMCID: PMC8422677 DOI: 10.1007/s11030-020-10068-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2019] [Accepted: 02/28/2020] [Indexed: 12/20/2022]
Abstract
GABA (γ-amino butyric acid) is an important inhibitory neurotransmitter in the central nervous system. Attenuation of GABAergic neurotransmission plays an important role in the etiology of several neurological disorders including epilepsy, Alzheimer's disease, Huntington's chorea, migraine, Parkinson's disease, neuropathic pain, and depression. Increase in the GABAergic activity may be achieved through direct agonism at the GABAA receptors, inhibition of enzymatic breakdown of GABA, or by inhibition of the GABA transport proteins (GATs). These functionalities make GABA receptor modulators and GATs attractive drug targets in brain disorders associated with decreased GABA activity. There have been several reports of development of GABA modulators (GABA receptors, GABA transporters, and GABAergic enzyme inhibitors) in the past decade. Therefore, the focus of the present review is to provide an overview on various design strategies and synthetic approaches toward developing GABA modulators. Furthermore, mechanistic insights, structure-activity relationships, and molecular modeling inputs for the biologically active derivatives have also been discussed. Summary of the advances made over the past few years in the clinical translation and development of GABA receptor modulators is also provided. This compilation will be of great interest to the researchers working in the field of neuroscience. From the light of detailed literature, it can be concluded that numerous molecules have displayed significant results and their promising potential, clearly placing them ahead as potential future drug candidates.
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Affiliation(s)
- Kavita Bhagat
- Department of Pharmaceutical Sciences, Guru Nanak Dev University, Amritsar, PB, 143005, India
| | - Jatinder V Singh
- Department of Pharmaceutical Sciences, Guru Nanak Dev University, Amritsar, PB, 143005, India
| | - Piyusha P Pagare
- Department of Medicinal Chemistry, School of Pharmacy and Institute for Structural Biology, Drug Discovery and Development, Virginia Commonwealth University, Richmond, VA, 23219, USA
| | - Nitish Kumar
- Department of Pharmaceutical Sciences, Guru Nanak Dev University, Amritsar, PB, 143005, India
| | - Anchal Sharma
- Department of Pharmaceutical Sciences, Guru Nanak Dev University, Amritsar, PB, 143005, India
| | - Gurinder Kaur
- Department of Pharmaceutical Sciences, Guru Nanak Dev University, Amritsar, PB, 143005, India
| | - Nihar Kinarivala
- Program in Chemical Biology, Sloan Kettering Institute, New York, NY, 10065, USA
| | - Srinivasa Gandu
- Department of Cell Biology and Neuroscience, Cell and Development Biology Graduate Program, The State University of New Jersey, Piscataway, NJ, 08854, USA
| | - Harbinder Singh
- Department of Pharmaceutical Sciences, Guru Nanak Dev University, Amritsar, PB, 143005, India.
| | - Sahil Sharma
- Department of Pharmaceutical Sciences, Guru Nanak Dev University, Amritsar, PB, 143005, India.
- Program in Chemical Biology, Sloan Kettering Institute, New York, NY, 10065, USA.
| | - Preet Mohinder S Bedi
- Department of Pharmaceutical Sciences, Guru Nanak Dev University, Amritsar, PB, 143005, India.
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Kumar U, Heer M, Somvanshi RK. Regional and subcellular distribution of GABA C ρ3 receptor in brain of R6/2 mouse model of Huntington's disease. Neurosci Lett 2017; 640:81-87. [PMID: 28104430 DOI: 10.1016/j.neulet.2017.01.035] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2016] [Revised: 12/24/2016] [Accepted: 01/15/2017] [Indexed: 10/20/2022]
Abstract
In the present study, we describe the distribution of GABAC ρ3 receptor immunoreactivity in the cortex, striatum and hippocampus of wild type (wt) and 11 weeks old HD transgenic (tg) R6/2 mouse brain. In the brain of wt mice, GABAC ρ3 immunoreactivity is well expressed in neuronal cells, nerve fibers and axonal processes. In comparison to wt, GABAC ρ3 receptor like immunoreactivity decreases significantly in all three brain regions of R6/2 mice. The altered distributional pattern and significant changes in GABAC ρ3 receptor immunoreactivity as seen in the R6/2 mouse brain might be a plausible molecular mechanism for excitotoxicity in HD pathogenesis due to the loss of inhibitory input.
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Affiliation(s)
- Ujendra Kumar
- Faculty of Pharmaceutical Sciences, The University of British Columbia, Vancouver, BC, Canada.
| | - Michael Heer
- Faculty of Pharmaceutical Sciences, The University of British Columbia, Vancouver, BC, Canada
| | - Rishi K Somvanshi
- Faculty of Pharmaceutical Sciences, The University of British Columbia, Vancouver, BC, Canada
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Ma Z, Niu B, Shi Z, Li J, Wang J, Zhang F, Gao X, Zhang K. Genetic Polymorphism of GABRR2 Modulates Individuals' General Cognitive Ability in Healthy Chinese Han People. Cell Mol Neurobiol 2016; 37:93-100. [PMID: 26922432 DOI: 10.1007/s10571-016-0347-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2015] [Accepted: 02/08/2016] [Indexed: 01/04/2023]
Abstract
Previous studies have indicated that the cognitive impairment or deficit is associated with GABAergic signaling in central nervous system. Inspired by the finding that receptor GABRR2 modulates concentration of GABA and phasic inhibitory GABAergic transmission in brain. This study investigated to what extent a genetic variant (c.1423C>T, rs282129) of GABRR2 gene modulates individuals' general cognitive ability in 987 Chinese Han people. Results showed a significant influence of GABRR2 gene polymorphism on individuals' Raven's Standard Progressive Matrices (RSPM) performance (F = 3.58, P = .028 by ANOVA and χ 2 = 9.35, P = .009 by K-W test, respectively), even if non-genetic factors were partialed out (gender, major, types of birthplace, and socioeconomic index) (B = -.67, SE = .26, t = 2.63, P = .009). The finding provided a strong evidence, to our knowledge, for the view that genetic variant of GABRR2 gene may contribute to the difference of individuals' general cognitive ability, independently.
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Affiliation(s)
- Zhe Ma
- Key Laboratory of Resource Biology and Biotechnology in Western China (Ministry of Education), Institute of Population and Health, College of Life Science, Northwest University, Xi'an, 710069, China
| | - Binbin Niu
- Key Laboratory of Resource Biology and Biotechnology in Western China (Ministry of Education), Institute of Population and Health, College of Life Science, Northwest University, Xi'an, 710069, China
| | - Zhangyan Shi
- Key Laboratory of Resource Biology and Biotechnology in Western China (Ministry of Education), Institute of Population and Health, College of Life Science, Northwest University, Xi'an, 710069, China
| | - Junlin Li
- Key Laboratory of Resource Biology and Biotechnology in Western China (Ministry of Education), Institute of Population and Health, College of Life Science, Northwest University, Xi'an, 710069, China
| | - Jian Wang
- Department of Applied Psychology, Institute of Applied Psychology, College of Public Management, Northwest University, Xi'an, 710069, China
| | - Fuchang Zhang
- Key Laboratory of Resource Biology and Biotechnology in Western China (Ministry of Education), Institute of Population and Health, College of Life Science, Northwest University, Xi'an, 710069, China.,Department of Applied Psychology, Institute of Applied Psychology, College of Public Management, Northwest University, Xi'an, 710069, China
| | - Xiaocai Gao
- Key Laboratory of Resource Biology and Biotechnology in Western China (Ministry of Education), Institute of Population and Health, College of Life Science, Northwest University, Xi'an, 710069, China. .,Department of Applied Psychology, Institute of Applied Psychology, College of Public Management, Northwest University, Xi'an, 710069, China. .,School of Public Management, Institute of Application Psychology, Institute of Population and Health, Northwest University, Xi'an, 710127, China.
| | - Kejin Zhang
- Key Laboratory of Resource Biology and Biotechnology in Western China (Ministry of Education), Institute of Population and Health, College of Life Science, Northwest University, Xi'an, 710069, China.
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Ye F, Liu Y, Jin Y, Shi J, Yang X, Liu X, Zhang X, Lin S, Kong Y, Zhang L. The effect of hepatitis B virus infected embryos on pregnancy outcome. Eur J Obstet Gynecol Reprod Biol 2013; 172:10-4. [PMID: 24188613 DOI: 10.1016/j.ejogrb.2013.10.002] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2013] [Revised: 09/16/2013] [Accepted: 10/01/2013] [Indexed: 01/22/2023]
Abstract
OBJECTIVE HBV vertical transmission is the main reason for chronic HBV infection, but there is no clear conclusion about the effect of HBV infection on pregnancy outcome. This study aimed to investigate the effect of HBV-infected embryos on pregnancy outcome. STUDY DESIGN 75 couples who received ART treatment were followed up. Among them were 25 couples (group A) with at least the husband or wife infected with HBV, and 50 couples (group B) with negative serum HBV markers of both husband and wife. The clinical pregnancy rate, early abortion rate, neonatal malformation rate, neonatal HBV infection rate, and HBV infection rate of the six-month-old infant were compared between these two groups, and Fisher's exact test was applied. HBV mRNA in abandoned embryos of the patients was detected by single-cell RT-PCR. RESULTS Both the early abortion rate and the abortion rate with the mother infected HBV in group A were significantly higher than in group B (P=0.043, P=0.030 respectively). The clinical pregnancy rates of groups A and B were 36% and 44% respectively (P=0.248>0.05). The neonatal malformation rate, neonatal HBV infection rate, and HBV infection rate of six-month-old infants in group A and group B were all 0. Specific HBV mRNA fragments were detected in 6 cases of 62 cleavage embryos in group A, giving a positive rate of 9.7%. The positive rates with mother infected and father infected with HBV were 13.2% (5/38) and 5.6% (1/18) respectively. CONCLUSIONS HBV infection can increase the early abortion rate of pregnancy, and the reason may be related to HBV-infected embryos.
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Affiliation(s)
- Feng Ye
- Department of Infectious Diseases, the First Affiliated Hospital, Xi'an Jiaotong University, Xi'an Yanta Road No. 277, Xi'an 710061, Shaanxi Province, China
| | - Yi Liu
- Department of Traditional Chinese Medicine, the First Affiliated Hospital, Xi'an Jiaotong University, Xi'an Yanta Road No. 277, Xi'an 710061, Shaanxi Province, China.
| | - Yan Jin
- Department of Gastroenterology, Shaanxi Provincial People's Hospital, Youyixi Road, 256#, Xi'an 710068, Shaanxi Province, China
| | - Juanzi Shi
- Department of Reproductive and Endocrinology, Shaanxi Maternal and Child Health Hospital, Houzaimen, 73#, Xi'an 710003, Shaanxi Province, China
| | - Xueliang Yang
- Department of Infectious Diseases, the First Affiliated Hospital, Xi'an Jiaotong University, Xi'an Yanta Road No. 277, Xi'an 710061, Shaanxi Province, China
| | - Xiaojing Liu
- Department of Infectious Diseases, the First Affiliated Hospital, Xi'an Jiaotong University, Xi'an Yanta Road No. 277, Xi'an 710061, Shaanxi Province, China
| | - Xi Zhang
- Department of Infectious Diseases, the First Affiliated Hospital, Xi'an Jiaotong University, Xi'an Yanta Road No. 277, Xi'an 710061, Shaanxi Province, China
| | - Shumei Lin
- Department of Infectious Diseases, the First Affiliated Hospital, Xi'an Jiaotong University, Xi'an Yanta Road No. 277, Xi'an 710061, Shaanxi Province, China
| | - Ying Kong
- Department of Infectious Diseases, the First Affiliated Hospital, Xi'an Jiaotong University, Xi'an Yanta Road No. 277, Xi'an 710061, Shaanxi Province, China
| | - Linshu Zhang
- Department of Infectious Diseases, the First Affiliated Hospital, Xi'an Jiaotong University, Xi'an Yanta Road No. 277, Xi'an 710061, Shaanxi Province, China
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YE F, JIN Y, KONG Y, SHI JZ, QIU HT, ZHANG X, ZHANG SL, LIN SM. The presence of HBV mRNA in the fertilized in vitro embryo of HBV patients confirms vertical transmission of HBV via the ovum. Epidemiol Infect 2013; 141:926-30. [PMID: 22877604 PMCID: PMC9151867 DOI: 10.1017/s0950268812001690] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2012] [Accepted: 07/11/2012] [Indexed: 12/12/2022] Open
Abstract
This study aimed to confirm that vertical transmission of hepatitis B virus (HBV) can occur via the infected ovum. Specimens studied were obtained from discarded test-tube embryos from mothers with chronic HBV infection who had received in vitro fertilization treatment. Single-cell reverse transcriptase-polymerase chain reaction was used to detect HBV mRNA in the embryos. HBV mRNA was detected in the cleavage embryos of patients with chronic HBV infection, with a detection rate of 13.2% (5/38). The level of serum HBV DNA was not related to the HBV mRNA positivity rates in embryos. In this study, HBV mRNA was detected in test-tube embryos from HBV-infected mothers who had received in vitro fertilization treatment. This confirms the theory of vertical transmission of HBV via the ovum, thereby providing an important theoretical basis for further study on the mechanism of HBV vertical transmission, influencing factors and blocking measures.
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Affiliation(s)
- F. YE
- Departments of Infectious Disease and Gynecology and Obstetrics, The First Hospital of Xi'an Jiaotong University, Xi'an, China
| | - Y. JIN
- Departments of Infectious Disease and Gynecology and Obstetrics, The First Hospital of Xi'an Jiaotong University, Xi'an, China
| | - Y. KONG
- Departments of Infectious Disease and Gynecology and Obstetrics, The First Hospital of Xi'an Jiaotong University, Xi'an, China
| | - J. Z. SHI
- Reproductive Center, Shanxi Maternal and Child Care Hospital, Xi'an, China
| | - H. T. QIU
- Reproductive Center, Shanxi Maternal and Child Care Hospital, Xi'an, China
| | - X. ZHANG
- Departments of Infectious Disease and Gynecology and Obstetrics, The First Hospital of Xi'an Jiaotong University, Xi'an, China
| | - S. L. ZHANG
- Departments of Infectious Disease and Gynecology and Obstetrics, The First Hospital of Xi'an Jiaotong University, Xi'an, China
| | - S. M. LIN
- Departments of Infectious Disease and Gynecology and Obstetrics, The First Hospital of Xi'an Jiaotong University, Xi'an, China
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6
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Shi Y, Wang SH, Zhang FM. Role of γ-aminobutyric acid and its receptors in carcinogenesis. Shijie Huaren Xiaohua Zazhi 2012; 20:399-404. [DOI: 10.11569/wcjd.v20.i5.399] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Gamma-aminobutyric acid (GABA) is a major inhibitory neurotransmitter in the adult mammalian brain and it is also expressed in the central nervous system, peripheral nerves and peripheral non-neural tissues. Recent studies have shown that GABA is involved in the proliferation and migration of tumor cells and other processes of tumor development. According to different sensitivity to agonists and antagonists, GABA receptors have been classified into three types: A, B and C. GABA receptors and their receptor subunits are involved in complicated regulation of tumor cells. Many studies have demonstrated that GABA binding to its receptors can activate or inhibit the cAMP signaling pathway and the MAPK/ERK pathway, and regulate cancer cell proliferation and migration. The potential value of GABA in cancer diagnosis, prognostic prediction and biotherapy has been gradually revealed. In the present article, we reviewed the recent progress in understanding the role of GABA and its receptors in carcinogenesis.
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7
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Martínez-Delgado G, Estrada-Mondragón A, Miledi R, Martínez-Torres A. An Update on GABAρ Receptors. Curr Neuropharmacol 2011; 8:422-33. [PMID: 21629448 PMCID: PMC3080597 DOI: 10.2174/157015910793358141] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2009] [Revised: 04/08/2010] [Accepted: 06/21/2010] [Indexed: 01/29/2023] Open
Abstract
The present review discusses the functional and molecular diversity of GABAρ receptors. These receptors were originally described in the mammalian retina, and their functional role in the visual pathway has been recently elucidated; however new studies on their distribution in the brain and spinal cord have revealed that they are more spread than originally thought, and thus it will be important to determine their physiological contribution to the GABAergic transmission in other areas of the central nervous system. In addition, molecular modeling has revealed peculiar traits of these receptors that have impacted on the interpretations of the latest pharmacolgical and biophysical findings. Finally, sequencing of several vertebrate genomes has permitted a comparative analysis of the organization of the GABAρ genes.
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Affiliation(s)
- Gustavo Martínez-Delgado
- Instituto de Neurbiología, Departamento de Neurobiología Celular y Molecular, Laboratorio D15, Campus UNAM Juriquilla. Querétaro 76230, México
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8
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Johnston GAR, Chebib M, Hanrahan JR, Mewett KN. Neurochemicals for the investigation of GABA(C) receptors. Neurochem Res 2010; 35:1970-7. [PMID: 20963487 DOI: 10.1007/s11064-010-0271-7] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/13/2010] [Indexed: 01/23/2023]
Abstract
GABA(C) receptors are being investigated for their role in many aspects of nervous system function including memory, myopia, pain and sleep. There is evidence for functional GABA(C) receptors in many tissues such as retina, hippocampus, spinal cord, superior colliculus, pituitary and the gut. This review describes a variety of neurochemicals that have been shown to be useful in distinguishing GABA(C) receptors from other receptors for the major inhibitory neurotransmitter GABA. Some selective agonists (including (+)-CAMP and 5-methyl-IAA), competitive antagonists (such as TPMPA, (±)-cis-3-ACPBPA and aza-THIP), positive (allopregnanolone) and negative modulators (epipregnanolone, loreclezole) are described. Neurochemicals that may assist in distinguishing between homomeric ρ1 and ρ2 GABA(C) receptors (2-methyl-TACA and cyclothiazide) are also covered. Given their less widespread distribution, lower abundance and relative structural simplicity compared to GABA(A) and GABA(B) receptors, GABA(C) receptors are attractive drug targets.
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Affiliation(s)
- Graham A R Johnston
- Adrien Albert Laboratory of Medicinal Chemistry, Department of Pharmacology D06, The University of Sydney, Sydney, NSW 2006, Australia.
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9
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Abstract
The activity of many receptors and ion channels in the nervous system can be regulated by redox-dependent mechanisms. Native and recombinant GABA(A) receptors are modulated by endogenous and pharmacological redox agents. However, the sensitivity of GABA(C) receptors to redox modulation has not been demonstrated. We studied the actions of different reducing and oxidizing agents on human homomeric GABArho(1) receptors expressed in Xenopus laevis oocytes. The reducing agents dithiothreitol (2 mM) and N-acetyl-L-cysteine (1 mM) potentiated GABA-evoked Cl(-) currents recorded by two-electrode voltage-clamp, while the oxidants 5-5'-dithiobis-2-nitrobenzoic acid (500 microM) and oxidized dithiothreitol (2 mM) caused inhibition. The endogenous antioxidant glutathione (5 mM) also enhanced GABArho(1) receptor-mediated currents while its oxidized form GSSG (3 mM) had inhibitory effects. All the effects were rapid and easily reversible. Redox modulation of GABArho(1) receptors was strongly dependent on the GABA concentration; dose-response curves for GABA were shifted to the left in the presence of reducing agents, whereas oxidizing agents produced the opposite effect, without changes in the maximal response to GABA and in the Hill coefficient. Our results demonstrate that, similarly to GABA(A) receptors and other members of the cys-loop receptor superfamily, GABA(C) receptors are subjected to redox modulation.
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Affiliation(s)
- Cecilia I Calero
- Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Facultad de Ciencias Exactas y Naturales Universidad de Buenos Aires (UBA), Ciudad Autónoma de Buenos Aires, Argentina
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Abstract
Functional studies of the ligand gated ion channel family (nicotinic acetylcholine, serotonin Type 3, glycine and GABA receptors) along with the crystal structure of the acetylcholine binding protein (AChBP) and molecular dynamics simulations of the nAChR structure have resulted in a structural model in which the agonist-binding pocket comprises six loops (A-F) contributed by adjacent subunits. It is presumed that the binding of agonist results in a local structural rearrangement that is then transduced to the gate, causing the pore to open. Efforts are underway to better define the specific roles of the six binding loops. Several studies have suggested Loop F may play a direct role in linking the structural rearrangement within the binding pocket to the gate, although other investigations have indicated Loop F may be crucial for locking the agonist molecule into the binding site. This review will focus on the controversy surrounding the role of Loop F during GABA receptor activation.
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Affiliation(s)
- Alpa Khatri
- Department of Physiology, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA
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Watanabe Y, Kaida Y, Takechi K, Kamei C. Anticonvulsant Effect of (RS)-1-Aminoindan-1,5-dicarboxylic Acid on Pentetrazol-Induced Kindled Seizures in Mice. Biol Pharm Bull 2010; 33:647-52. [DOI: 10.1248/bpb.33.647] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Affiliation(s)
- Yusuke Watanabe
- Department of Medicinal Pharmacology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences
| | - Yuko Kaida
- Department of Medicinal Pharmacology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences
| | - Kenshi Takechi
- Department of Medicinal Pharmacology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences
| | - Chiaki Kamei
- Department of Medicinal Pharmacology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences
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12
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Wahle P, Schmidt M. GABAC receptors are expressed in GABAergic and non-GABAergic neurons of the rat superior colliculus and visual cortex. Exp Brain Res 2009; 199:245-52. [DOI: 10.1007/s00221-009-1710-z] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2008] [Accepted: 01/09/2009] [Indexed: 10/21/2022]
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Xu JY, Yang B, Sastry BR. The involvement of GABA-C receptors in paired-pulse depression of inhibitory postsynaptic currents in rat hippocampal CA1 pyramidal neurons. Exp Neurol 2008; 216:243-6. [PMID: 19100735 DOI: 10.1016/j.expneurol.2008.11.013] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2008] [Revised: 11/04/2008] [Accepted: 11/19/2008] [Indexed: 11/25/2022]
Abstract
In rat hippocampal CA1 pyramidal neurons, gamma-aminobutyric acid (GABA) A receptor-mediated inhibitory postsynaptic currents (IPSCs) undergo a paired-pulse depression (PPD) by the second of two pulses, with inter-pulse intervals of 100-2000 ms, applied to the stratum radiatum. While GABA-C receptors are described in the CA1 area, their functional significance is unknown. In this study, the involvement of GABA-C receptors in PPD was examined using an in vitro hippocampal slice preparation. IPSCs evoked by stimulations in stratum radiatum were recorded with patch pipettes from CA1 pyramidal cells. PPD, when induced in the above fashion, was blocked by the GABA-C receptor antagonist (1,2,5,6-Tetrahydropyridin-4-yl) methylphosphinic acid (TPMPA, 10 muM, applied in the superfusing medium). GABA-A and GABA-B receptor-mediated IPSCs, as well as the baclofen-induced suppression of the GABA-A receptor mediated IPSC, were not antagonized by TPMPA (10-20 muM). These results indicate that PPD of the IPSC is mediated by the activation of GABA-C receptors.
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Affiliation(s)
- J-Y Xu
- Neuroscience Research Laboratory, Department of Anesthesiology, Pharmacology and Therapeutics, Faculty of Medicine, The University of British Columbia, Vancouver, BC, Canada
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14
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Carter LP, Koek W, France CP. Behavioral analyses of GHB: receptor mechanisms. Pharmacol Ther 2008; 121:100-14. [PMID: 19010351 DOI: 10.1016/j.pharmthera.2008.10.003] [Citation(s) in RCA: 122] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2008] [Accepted: 10/14/2008] [Indexed: 11/25/2022]
Abstract
GHB is used therapeutically and recreationally, although the precise mechanism of action responsible for its different behavioral effects is not entirely clear. The purpose of this review is to summarize how behavioral procedures, especially drug discrimination procedures, have been used to study the mechanism of action of GHB. More specifically, we will review several different drug discrimination procedures and discuss how they have been used to qualitatively and quantitatively study different components of the complex mechanism of action of GHB. A growing number of studies have provided evidence that the behavioral effects of GHB are mediated predominantly by GABAB receptors. However, there is also evidence that the mechanisms mediating the effects of GHB and the prototypical GABAB receptor agonist baclofen are not identical, and that other mechanisms such as GHB receptors and subtypes of GABAA and GABAB receptors might contribute to the effects of GHB. These findings are consistent with the different behavioral profile, abuse liability, and therapeutic indications of GHB and baclofen. A better understanding of the similarities and differences between GHB and baclofen, as well as the pharmacological mechanisms of action underlying the recreational and therapeutic effects of GHB, could lead to more effective medications with fewer adverse effects.
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15
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Inhibitory interaction between P2X4 and GABA(C) rho1 receptors. Biochem Biophys Res Commun 2008; 375:38-43. [PMID: 18675255 DOI: 10.1016/j.bbrc.2008.07.096] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2008] [Accepted: 07/18/2008] [Indexed: 01/16/2023]
Abstract
Reciprocal functional inhibition between P2X and GABA(A/C) receptors represents a novel mechanism fine-tuning neuronal excitability. However, the participating receptors and underlying mechanisms are not fully understood. P2X(4) receptor is widely found in neurons that express GABA(C) rho1 receptor. Thus, we co-expressed P2X(4) and rho1 receptors in HEK293 cells and, using patch-clamp recording, examined whether they have mutual functional inhibition. Currents evoked by simultaneous application of ATP and GABA (I(ATP+GABA)) were significantly smaller compared to the addition of I(ATP) and I(GABA). Furthermore, I(ATP) were strongly suppressed during rho1 receptor activation. Similarly, I(GABA) were greatly attenuated during P2X(4) receptor activation. Such mutual inhibition was absent in cells only expressing P2X(4) or rho1 receptor. Taken together, these functional data support negative cross-talk between P2X(4) and rho1 receptors.
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16
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Rosas-Arellano A, Ochoa-de la Paz LD, Miledi R, Martínez-Torres A. Brain distribution and molecular cloning of the bovine GABA rho1 receptor. Neurosci Res 2007; 57:347-53. [PMID: 17188384 DOI: 10.1016/j.neures.2006.11.003] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2006] [Revised: 10/06/2006] [Accepted: 11/06/2006] [Indexed: 10/23/2022]
Abstract
GABA(C) receptors were originally found in the mammalian retina and recent evidence shows that they are also expressed in several areas of the brain, including caudate nucleus, brain stem, pons and corpus callosum. In this study, plasma membranes from the caudate nucleus were microinjected into X. laevis oocytes. This led the oocyte plasma membrane to incorporate functional bicuculline-resistant, Cl(-) conducting bovine GABA receptors, similar to those of the retina. Immunolocalization of the GABA rho1 subunit revealed its expression in bovine neurons in the head of the caudate as well as in the olive, cuneiform and reticular nuclei of the brain stem. The same antibodies failed to show expression in the callosum and pons, where the GABA rho1 mRNA was previously detected. The cloned GABA rho1 sequence predicts a protein with 473 amino acids and 74-93% similarity to other GABA rho1 subunits. Oocytes injected with the cDNA express a non-desensitizing, homomeric receptor with a GABA EC(50)=6.0 microM and a Hill coefficient of 1.8. The results confirm the presence of GABA(C) receptor mRNAs in several areas of the mammalian brain and show that some of these areas express functional GABA rho1 receptors that have the classic GABA(C) receptor characteristics.
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Affiliation(s)
- Abraham Rosas-Arellano
- Instituto de Neurobiología, Laboratorio de Neurobiología Molecular y Celular II, Universidad Nacional Autónoma de México, Km 15.5 Carretera a San Luis Potosí 76001 Juriquilla, Querétaro, México
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Cheng Q, Yeh PWL, Yeh HH. Cajal-Retzius cells switch from expressing gamma-less to gamma-containing GABA receptors during corticogenesis. Eur J Neurosci 2006; 24:2145-51. [PMID: 17074040 DOI: 10.1111/j.1460-9568.2006.05122.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Cajal-Retzius cells are implicated in regulating neuronal migration and lamination during corticogenesis. In rodents, Cajal-Retzius cells are transient, being prevalent in the marginal zone of the embryonic neocortex and declining over the first two postnatal weeks. While studies have examined in postnatal neocortex the properties of GABA(A) receptors in Cajal-Retzius cells, less is known about their disposition at embryonic stages. Here, we combined patch-clamp electrophysiology and single-cell mRNA profiling to probe the expression of GABA(A) receptors in Cajal-Retzius cells. In embryonic neocortical slices, GABA elicited GABA(A) receptor-mediated current responses that were diazepam-insensitive and inhibited by Zn(2+), a pharmacological profile consistent with expression of gamma-less GABA(A) receptor isoforms. Non-Cajal-Retzius cells in the same embryonic slices, on the other hand, were robustly potentiated by diazepam and were insensitive to Zn(2+), typical of gamma-containing GABA(A) receptor isoforms, as were Cajal-Retzius cells in the postnatal neocortex. Single-cell mRNA profiling and immunohistochemistry confirmed expression of GABA(A) receptor gamma subunit transcript and protein, respectively, in individual reelin-expressing cells in the postnatal cortex but not in their embryonic counterparts. We conclude that Cajal-Retzius cells express gamma-less GABA(A) receptors at embryonic stages and switch to expressing gamma-containing GABA(A) receptor isoforms during postnatal neocortical development.
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Affiliation(s)
- Qing Cheng
- Department of Physiology, Dartmouth Medical School, Dartmouth-Hitchcock Medical Center, One Medical Center Drive, Lebanon, NH 03756, USA
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Yang J, Cheng Q, Takahashi A, Goubaeva F. Kinetic properties of GABA rho1 homomeric receptors expressed in HEK293 cells. Biophys J 2006; 91:2155-62. [PMID: 16798806 PMCID: PMC1557572 DOI: 10.1529/biophysj.106.085431] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2006] [Accepted: 06/09/2006] [Indexed: 11/18/2022] Open
Abstract
The rho1 subunit of the ionotropic GABA receptors is thought to contribute to the formation of the GABA(C) receptors with pharmacological and physiological properties distinct from those of GABA(A) receptors. Previous characterization of this subunit expressed in the Xenopus oocytes revealed an ion channel with slow activation and deactivation and no desensitization, quite different from the properties of GABA(C) receptors observed in native cells. We expressed the human rho1 subunit in human embryonic kidney (HEK) 293 cells and quantitatively characterized the kinetic properties of these receptors using a rapid drug application device. The rho1 subunit expressed in HEK293 cells exhibited pharmacological and kinetic properties qualitatively identical to those described when rho1 was expressed in the oocytes. An apparent desensitizing current observed during a constant GABA application was determined to be secondary to an E(Cl) shift. Detailed kinetic analyses and parameter estimation for a five-state kinetic model revealed that the channel is best described by a set of rate constants with a notably faster GABA unbinding K(off) rate compared to the parameters proposed for the same subunit expressed in the oocytes. The same subunit expressed in hippocampal neurons showed activation and deactivation kinetics identical to the current characterized in HEK293 cells. The kinetic properties of rho1 subunit expressed in a nonoocyte model system may be better described quantitatively by the rate constants presented here.
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Affiliation(s)
- Jay Yang
- Department of Anesthesiology, Columbia University College of Physicians & Surgeons, 630 West 168th Street, New York, NY 10032, USA.
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Nakayama Y, Hattori N, Otani H, Inagaki C. Gamma-aminobutyric acid (GABA)-C receptor stimulation increases prolactin (PRL) secretion in cultured rat anterior pituitary cells. Biochem Pharmacol 2006; 71:1705-10. [PMID: 16677614 DOI: 10.1016/j.bcp.2006.03.014] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2006] [Accepted: 03/14/2006] [Indexed: 11/22/2022]
Abstract
Gamma-aminobutyric acid (GABA) reportedly inhibits secretion of anterior pituitary hormones by directly acting on GABA-A and GABA-B receptors on anterior pituitary cells, but the roles of GABA-C receptors are little known. In this study, involvement of GABA-C receptors in the secretion of prolactin (PRL) was examined using cultured rat anterior pituitary cells. GABA-C receptor agonist, cis-4-aminocrotonic acid (CACA, 0.1-1 mM) increased PRL secretion dose-dependently, while GABA-A receptor agonist, 100 microM muscimol, but not GABA-B receptor agonist, 100 microM baclofen, decreased the secretion. GABA-C receptor antagonist, 15 microM (1,2,5,6-tetrahydropyridin-4-yl) methylphosphinic acid (TPMPA), and GABA-A receptor antagonist, 100 microM bicuculline, not only reversed such an agonist-induced increase or decrease in PRL secretion, but also suppressed or enhanced spontaneous PRL secretion, raising a possibility of GABA-C or GABA-A receptor stimulation by intrinsic pituitary-derived GABA. GABA-C receptor subunits (rho1, rho2, rho3) and GABA synthesizing enzymes (GAD 65 and GAD 67) were shown to be expressed as assayed by RT-PCR, and GABA-C receptor stimulation by CACA obviously increased intracellular Ca2+ concentration in the anterior pituitary cells. Thus, PRL secretion from anterior pituitary cells appears to be enhanced via direct GABA-C receptor stimulation by GABA originating from the anterior pituitary cells besides well-known hypothalamic GABA.
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Affiliation(s)
- Yasuhisa Nakayama
- Department of Pharmacology, Kansai Medical University, Osaka 570-8506, Japan.
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Shen J, Harada N, Kubo N, Liu B, Mizuno A, Suzuki M, Yamashita T. Functional expression of transient receptor potential vanilloid 4 in the mouse cochlea. Neuroreport 2006; 17:135-9. [PMID: 16407759 DOI: 10.1097/01.wnr.0000199459.16789.75] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Transient receptor potential vanilloid 4, the Ca2+-permeable cation channel has been proposed as an osmosensitive and a mechanosensitive channel. We investigated functional expression of transient receptor potential vanilloid 4 in inner hair cells, outer hair cells, and spiral ganglion neurons of the mouse cochlea. Transient receptor potential vanilloid 4 mRNA and protein were expressed in inner hair cells, outer hair cells, and spiral ganglion neurons on the basis of the findings of reverse transcriptase-polymerase chain reaction, single-cell reverse transcriptase-polymerase chain reaction, and immunohistochemistry, whereas they were negative in transient receptor potential vanilloid 4-/- mice cochleae. Hypotonic stimulation and 4-alpha-phorbol 12,13-didecanoate, a transient receptor potential vanilloid 4 synthetic activator, increased the intracellular Ca2+ concentrations in wild-type outer hair cells, whereas in transient receptor potential vanilloid 4-/- mice, outer hair cells failed to exhibit a Ca2+ response to both stimulations. In conclusion, transient receptor potential vanilloid 4 may function as an osmosensory and a mechanosensory receptor in the cochlea.
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Affiliation(s)
- Jing Shen
- Hearing Research Laboratory, Department of Otolaryngology, Kansai Medical University, Moriguchi, Japan
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Liu B, Hattori N, Zhang NY, Wu B, Yang L, Kitagawa K, Xiong ZM, Irie T, Inagaki C. Anxiolytic agent, dihydrohonokiol-B, recovers amyloid β protein-induced neurotoxicity in cultured rat hippocampal neurons. Neurosci Lett 2005; 384:44-7. [PMID: 15899548 DOI: 10.1016/j.neulet.2005.04.081] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2005] [Revised: 04/14/2005] [Accepted: 04/15/2005] [Indexed: 11/20/2022]
Abstract
The effects of anxiolytic honokiol derivative, dihydrohonokiol-B (DHH-B), on amyloid beta protein (Abeta(25-35), 10 nM)-induced changes in Cl(-)-ATPase activity, intracellular Cl- concentration ([Cl-]i) and glutamate neurotoxicity were examined in cultured rat hippocampal neurons. DHH-B (10 ng/ml) recovered Abeta-induced decrease in neuronal Cl(-)-ATPase activity without any changes in the activities of Na+/K+-ATPase and anion-insensitive Mg2+-ATPase. A GABA(C) receptor antagonist (1,2,5,6,-tetrahydropyridin-4-yl) methyl-phosphinic acid (TPMPA, 15 microM), inhibited the protective effects of DHH-B on Cl(-)-ATPase activity. DHH-B reduced Abeta-induced elevation of [Cl-]i as assayed using a Cl(-)-sensitive fluorescent dye, and prevented Abeta-induced aggravation of glutamate neurotoxicity. These data suggest that DHH-B exerts the neuroprotective action against Abeta through GABA(C) receptor stimulation.
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Affiliation(s)
- Bing Liu
- Department of Pharmacology, Kansai Medical University, 10-15 Fumizono-cho, Moriguchi City, Osaka 570-8506, Japan
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