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Bromazepam increases the error of the time interval judgments and modulates the EEG alpha asymmetry during time estimation. Conscious Cogn 2022; 100:103317. [PMID: 35364385 DOI: 10.1016/j.concog.2022.103317] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2021] [Revised: 03/19/2022] [Accepted: 03/23/2022] [Indexed: 11/23/2022]
Abstract
AIM This study investigated the bromazepam effects in male subjects during the time estimation performance and EEG alpha asymmetry in electrodes associated with the frontal and motor cortex. MATERIAL AND METHODS This is a double-blind, crossover study with a sample of 32 healthy adults under control (placebo) vs. experimental (bromazepam) during visual time-estimation task in combination with electroencephalographic analysis. RESULTS The results demonstrated that the bromazepam increased the relative error in the 4 s, 7 s, and 9 s intervals (p = 0.001). In addition, oral bromazepam modulated the EEG alpha asymmetry in cortical areas during the time judgment (p ≤ 0.025). CONCLUSION The bromazepam decreases the precision of time estimation judgments and modulates the EEG alpha asymmetry, with greater left hemispheric dominance during time perception. Our findings suggest that bromazepam influences internal clock synchronization via the modulation of GABAergic receptors, strongly relating to attention, conscious perception, and behavioral performance.
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2
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Guo F, Yi L, Zhang W, Bian ZJ, Zhang YB. Association Between Z Drugs Use and Risk of Cognitive Impairment in Middle-Aged and Older Patients With Chronic Insomnia. Front Hum Neurosci 2021; 15:775144. [PMID: 34955792 PMCID: PMC8696350 DOI: 10.3389/fnhum.2021.775144] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2021] [Accepted: 11/16/2021] [Indexed: 11/24/2022] Open
Abstract
Background: Benzodiazepines (BZDs) and Non-BZDs (NBZDs) have been widely used for patients with chronic insomnia. Long-term uses of BZDs may cause cognitive impairment and increase the risk for dementia in older patients. NBZD as an agonist of the GABAA receptor complex includes eszopiclone, zopiclone, zolpidem, and zaleplon, also collectively known as Z drugs. However, evaluations for an association between cognitive impairment and Z drug use have been limitedly performed. This study aimed to investigate the association between the risk of cognitive decline and exposure to Z drugs in middle-aged and older patients with chronic insomnia. Methods: Investigations were performed on patients with chronic insomnia who visited the outpatient Department of Neurology, Beijing Friendship Hospital, and were assessed for the global cognitive function (MoCA) and memory (AVLT), executive function (TMT-B), visuospatial ability (CDT), verbal function (BNT-30), and attention (DST). Multiple regression analysis was conducted to determine the independent factors of cognition and evaluated the effect of Z drug use (zolpidem and zopiclone) on cognition. Results: A total of 120 subjects were identified. In our analysis, BZD exposure density (P = 0.025, OR = 1.43, 95% CI, 1.25–1.86) was an independent risk factor of cognitive impairment in middle-aged and older patients with chronic insomnia. Neither Z drug use (P = 0.103) nor Z drug exposure density (P = 0.765) correlated with global cognitive function. Moreover, there was a positive association between Z drug use and attention [(P = 0.002, OR = 0.42, 95% CI, 0.24–0.73)]. Additionally, income level (P = 0.001, OR = 0.23, 95% CI, 0.10–0.53), severity of insomnia (P = 0.019, OR = 1.20, 95% CI, 1.03–1.40) and age (P = 0.044, OR = 1.07, 95% CI, 1.00–1.14) were also independent factors of global cognitive function. Conclusion: BZD exposure density was an independent risk factor of cognitive impairment in middle-aged and older patients with chronic insomnia, but no correlation was found between Z drug use and cognitive impairment. Moreover, the use of Z drugs seemed to be associated with protection for attention. The use for prescription of BZDs, in this case, should be avoided or limited to low doses. Due to the addiction and tolerance, Z drugs should also be prescribed with great caution in middle-aged and elderly patients.
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Affiliation(s)
- Fang Guo
- Department of Neurology, Beijing Friendship Hospital, Capital Medical University, Beijing, China
| | - Li Yi
- Department of Neurology, Beijing Friendship Hospital, Capital Medical University, Beijing, China
| | - Wei Zhang
- Department of Neurology, Beijing Friendship Hospital, Capital Medical University, Beijing, China
| | - Zhi-Jie Bian
- Department of Neurology, Beijing Friendship Hospital, Capital Medical University, Beijing, China
| | - Yong-Bo Zhang
- Department of Neurology, Beijing Friendship Hospital, Capital Medical University, Beijing, China
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3
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Furukawa T, Nikaido Y, Shimoyama S, Masuyama N, Notoya A, Ueno S. Impaired Cognitive Function and Hippocampal Changes Following Chronic Diazepam Treatment in Middle-Aged Mice. Front Aging Neurosci 2021; 13:777404. [PMID: 34899279 PMCID: PMC8664496 DOI: 10.3389/fnagi.2021.777404] [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: 09/15/2021] [Accepted: 11/04/2021] [Indexed: 01/07/2023] Open
Abstract
Background: Gamma-aminobutyric acid (GABA) type A receptors are positively allosterically modulated by benzodiazepine binding, leading to a potentiated response to GABA. Diazepam (DZP, a benzodiazepine) is widely prescribed for anxiety, epileptic discharge, and insomnia, and is also used as a muscle relaxant and anti-convulsant. However, some adverse effects - such as tolerance, dependence, withdrawal effects, and impairments in cognition and learning - are elicited by the long-term use of DZP. Clinical studies have reported that chronic DZP treatment increases the risk of dementia in older adults. Furthermore, several studies have reported that chronic DZP administration may affect neuronal activity in the hippocampus, dendritic spine structure, and cognitive performance. However, the effects of chronic DZP administration on cognitive function in aged mice is not yet completely understood. Methods: A behavioral test, immunohistochemical analysis of neurogenic and apoptotic markers, dendritic spine density analysis, and long-term potentiation (LTP) assay of the hippocampal CA1 and CA3 were performed in both young (8 weeks old) and middle-aged (12 months old) mice to investigate the effects of chronic DZP administration on cognitive function. The chronic intraperitoneal administration of DZP was performed by implanting an osmotic minipump. To assess spatial learning and memory ability, the Morris water maze test was performed. Dendritic spines were visualized using Lucifer yellow injection into the soma of hippocampal neurons, and spine density was analyzed. Moreover, the effects of exercise on DZP-induced changes in spine density and LTP in the hippocampus were assessed. Results: Learning performance was impaired by chronic DZP administration in middle-aged mice but not in young mice. LTP was attenuated by DZP administration in the CA1 of young mice and the CA3 of middle-aged mice. The spine density of hippocampal neurons was decreased by chronic DZP administration in the CA1 of both young and middle-aged mice as well as in the CA3 of middle-aged mice. Neither neurogenesis nor apoptosis in the hippocampus was affected by chronic DZP administration. Conclusion: The results of this study suggest that the effects of chronic DZP are different between young and middle-aged mice. The chronic DZP-induced memory retrieval performance impairment in middle-aged mice can likely be attributed to decreased LTP and dendritic spine density in hippocampal neurons in the CA3. Notably, prophylactic exercise suppressed the adverse effects of chronic DZP on LTP and spine maintenance in middle-aged mice.
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Affiliation(s)
- Tomonori Furukawa
- Department of Neurophysiology, Hirosaki University Graduate School of Medicine, Hirosaki, Japan
| | - Yoshikazu Nikaido
- Department of Frailty Research and Prevention, Hirosaki University Graduate School of Medicine, Hirosaki, Japan.,Department of Anesthesiology, Hirosaki University Graduate School of Medicine, Hirosaki, Japan
| | - Shuji Shimoyama
- Department of Neurophysiology, Hirosaki University Graduate School of Medicine, Hirosaki, Japan.,Research Center for Child Mental Development, Hirosaki University Graduate School of Medicine, Hirosaki, Japan
| | - Nozomu Masuyama
- Department of Neurophysiology, Hirosaki University Graduate School of Medicine, Hirosaki, Japan
| | - Ayaka Notoya
- Department of Neurophysiology, Hirosaki University Graduate School of Medicine, Hirosaki, Japan
| | - Shinya Ueno
- Department of Neurophysiology, Hirosaki University Graduate School of Medicine, Hirosaki, Japan.,Research Center for Child Mental Development, Hirosaki University Graduate School of Medicine, Hirosaki, Japan
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4
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Ettcheto M, Olloquequi J, Sánchez-López E, Busquets O, Cano A, Manzine PR, Beas-Zarate C, Castro-Torres RD, García ML, Bulló M, Auladell C, Folch J, Camins A. Benzodiazepines and Related Drugs as a Risk Factor in Alzheimer's Disease Dementia. Front Aging Neurosci 2020; 11:344. [PMID: 31969812 PMCID: PMC6960222 DOI: 10.3389/fnagi.2019.00344] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2019] [Accepted: 11/26/2019] [Indexed: 12/21/2022] Open
Abstract
Benzodiazepines (BZDs) and Z-drugs are compounds widely prescribed in medical practice due to their anxiolytic, hypnotic, and muscle relaxant properties. Yet, their chronic use is associated with cases of abuse, dependence, and relapse in many patients. Furthermore, elderly people are susceptible to alterations in pharmacodynamics, pharmacokinetics as well as to drug interaction due to polypharmacy. These situations increase the risk for the appearance of cognitive affectations and the development of pathologies like Alzheimer's disease (AD). In the present work, there is a summary of some clinical studies that have evaluated the effect of BZDs and Z-drugs in the adult population with and without AD, focusing on the relationship between their use and the loss of cognitive function. Additionally, there is an assessment of preclinical studies focused on finding molecular proof on the pathways by which these drugs could be involved in AD pathogenesis. Moreover, available data (1990-2019) on BZD and Z-drug use among elderly patients, with and without AD, was compiled in this work. Finally, the relationship between the use of BZD and Z-drugs for the treatment of insomnia and the appearance of AD biomarkers was analyzed. Results pointed to a vicious circle that would worsen the condition of patients over time. Likewise, it put into relevance the need for close monitoring of those patients using BZDs that also suffer from AD. Consequently, future studies should focus on optimizing strategies for insomnia treatment in the elderly by using other substances like melatonin agonists, which is described to have a much more significant safety profile.
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Affiliation(s)
- Miren Ettcheto
- Departament de Farmacologia, Toxicologia i Química Terapèutica, Facultat de Farmàcia i Ciències de l'Alimentació, Universitat de Barcelona, Barcelona, Spain
- Departament de Bioquímica i Biotecnologia, Facultat de Medicina i Ciències de la Salut, Universitat Rovira i Virgili, Reus, Spain
- Institut de Neurociències, Universitat de Barcelona, Barcelona, Spain
- Biomedical Research Networking Centre in Neurodegenerative Diseases (CIBERNED), Madrid, Spain
| | - Jordi Olloquequi
- Laboratory of Cellular and Molecular Pathology, Facultad de Ciencias de la Salud, Instituto de Ciencias Biomédicas, Universidad Autónoma de Chile, Talca, Chile
| | - Elena Sánchez-López
- Biomedical Research Networking Centre in Neurodegenerative Diseases (CIBERNED), Madrid, Spain
- Unitat de Farmàcia, Tecnologia Farmacèutica i Fisico-química, Facultat de Farmàcia i Ciències de l'Alimentació, Universitat de Barcelona, Barcelona, Spain
- Institute of Nanoscience and Nanotechnology (IN2UB), Universitat de Barcelona, Barcelona, Spain
| | - Oriol Busquets
- Departament de Farmacologia, Toxicologia i Química Terapèutica, Facultat de Farmàcia i Ciències de l'Alimentació, Universitat de Barcelona, Barcelona, Spain
- Departament de Bioquímica i Biotecnologia, Facultat de Medicina i Ciències de la Salut, Universitat Rovira i Virgili, Reus, Spain
- Institut de Neurociències, Universitat de Barcelona, Barcelona, Spain
- Biomedical Research Networking Centre in Neurodegenerative Diseases (CIBERNED), Madrid, Spain
| | - Amanda Cano
- Biomedical Research Networking Centre in Neurodegenerative Diseases (CIBERNED), Madrid, Spain
- Unitat de Farmàcia, Tecnologia Farmacèutica i Fisico-química, Facultat de Farmàcia i Ciències de l'Alimentació, Universitat de Barcelona, Barcelona, Spain
- Institute of Nanoscience and Nanotechnology (IN2UB), Universitat de Barcelona, Barcelona, Spain
| | | | - Carlos Beas-Zarate
- Laboratorio de Regeneración y Desarrollo Neural, Departamento de Biología Celular y Molecular, Instituto de Neurobiología, CUCBA, Guadalajara, Mexico
| | - Rubén D. Castro-Torres
- Laboratorio de Regeneración y Desarrollo Neural, Departamento de Biología Celular y Molecular, Instituto de Neurobiología, CUCBA, Guadalajara, Mexico
| | - Maria Luisa García
- Biomedical Research Networking Centre in Neurodegenerative Diseases (CIBERNED), Madrid, Spain
- Unitat de Farmàcia, Tecnologia Farmacèutica i Fisico-química, Facultat de Farmàcia i Ciències de l'Alimentació, Universitat de Barcelona, Barcelona, Spain
- Institute of Nanoscience and Nanotechnology (IN2UB), Universitat de Barcelona, Barcelona, Spain
| | - Mónica Bulló
- Departament de Bioquímica i Biotecnologia, Facultat de Medicina i Ciències de la Salut, Universitat Rovira i Virgili, Reus, Spain
- Institut d'Investigació Sanitària Pere Virgili (IISPV), Reus, Spain
- Centro de Investigación Biomédica en Red Fisiopatologia de la Obesidad y la Nutrición (CIBEROBN), Institut de Salud Carlos III, Madrid, Spain
| | - Carme Auladell
- Institut de Neurociències, Universitat de Barcelona, Barcelona, Spain
- Biomedical Research Networking Centre in Neurodegenerative Diseases (CIBERNED), Madrid, Spain
- Departament de Biologia Cellular, Fisiologia i Immunologia, Facultat de Biologia, Universitat de Barcelona, Barcelona, Spain
| | - Jaume Folch
- Departament de Bioquímica i Biotecnologia, Facultat de Medicina i Ciències de la Salut, Universitat Rovira i Virgili, Reus, Spain
- Biomedical Research Networking Centre in Neurodegenerative Diseases (CIBERNED), Madrid, Spain
| | - Antonio Camins
- Departament de Farmacologia, Toxicologia i Química Terapèutica, Facultat de Farmàcia i Ciències de l'Alimentació, Universitat de Barcelona, Barcelona, Spain
- Institut de Neurociències, Universitat de Barcelona, Barcelona, Spain
- Biomedical Research Networking Centre in Neurodegenerative Diseases (CIBERNED), Madrid, Spain
- Laboratory of Cellular and Molecular Pathology, Facultad de Ciencias de la Salud, Instituto de Ciencias Biomédicas, Universidad Autónoma de Chile, Talca, Chile
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Ujjainwala AL, Courtney CD, Wojnowski NM, Rhodes JS, Christian CA. Differential impacts on multiple forms of spatial and contextual memory in diazepam binding inhibitor knockout mice. J Neurosci Res 2019; 97:683-697. [PMID: 30680776 DOI: 10.1002/jnr.24393] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2018] [Revised: 01/04/2019] [Accepted: 01/14/2019] [Indexed: 02/03/2023]
Abstract
Learning and memory are fundamental processes that are disrupted in many neurological disorders including Alzheimer's disease and epilepsy. The hippocampus plays an integral role in these functions, and modulation of synaptic transmission mediated by γ-aminobutyric acid (GABA) type-A receptors (GABAA Rs) impacts hippocampus-dependent learning and memory. The protein diazepam binding inhibitor (DBI) differentially modulates GABAA Rs in various brain regions, including hippocampus, and changes in DBI levels may be linked to altered learning and memory. The effects of genetic loss of DBI signaling on these processes, however, have not been determined. In these studies, we examined male and female constitutive DBI knockout mice and wild-type littermates to investigate the role of DBI signaling in modulating multiple forms of hippocampus-dependent spatial learning and memory. DBI knockout mice did not show impaired discrimination of objects in familiar and novel locations in an object location memory test, but did exhibit reduced time spent exploring the objects. Multiple parameters of Barnes maze performance, testing the capability to utilize spatial reference cues, were disrupted in DBI knockout mice. Furthermore, whereas most wild-type mice adopted a direct search strategy upon learning the location of the target hole, knockout mice showed higher rates of using an inefficient random strategy. In addition, DBI knockout mice displayed typical levels of contextual fear conditioning, but lacked a sex difference observed in wild-type mice. Together, these data suggest that DBI selectively influences certain forms of spatial learning and memory, indicating novel roles for DBI signaling in modulating hippocampus-dependent behavior in a task-specific manner.
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Affiliation(s)
- Ammar L Ujjainwala
- Department of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign, Urbana, Illinois
| | - Connor D Courtney
- Neuroscience Program, University of Illinois at Urbana-Champaign, Urbana, Illinois
| | - Natalia M Wojnowski
- Department of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign, Urbana, Illinois
| | - Justin S Rhodes
- Neuroscience Program, University of Illinois at Urbana-Champaign, Urbana, Illinois.,Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, Illinois.,Department of Psychology, University of Illinois at Urbana-Champaign, Champaign, Illinois
| | - Catherine A Christian
- Department of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign, Urbana, Illinois.,Neuroscience Program, University of Illinois at Urbana-Champaign, Urbana, Illinois.,Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, Illinois
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6
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Szodorai E, Bampali K, Romanov RA, Kasper S, Hökfelt T, Ernst M, Lubec G, Harkany T. Diversity matters: combinatorial information coding by GABA A receptor subunits during spatial learning and its allosteric modulation. Cell Signal 2018; 50:142-159. [DOI: 10.1016/j.cellsig.2018.07.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2018] [Revised: 07/08/2018] [Accepted: 07/09/2018] [Indexed: 01/11/2023]
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7
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Casasola-Castro C, Weissmann-Sánchez L, Calixto-González E, Aguayo-Del Castillo A, Velázquez-Martínez DN. Short-term and long-term effects of diazepam on the memory for discrimination and generalization of scopolamine. Psychopharmacology (Berl) 2017; 234:3083-3090. [PMID: 28735367 DOI: 10.1007/s00213-017-4692-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/04/2017] [Accepted: 07/05/2017] [Indexed: 01/01/2023]
Abstract
Benzodiazepines are among the most widely prescribed and misused psychopharmaceutical drugs. Although they are well-tolerated, they are also capable of producing amnestic effects similar to those observed after pharmacological or organic cholinergic dysfunction. To date, the effect of benzodiazepine diazepam on the memory for discrimination of anticholinergic drugs has not been reported. The aim of the present study was to analyze the immediate and long-term effects of diazepam on a drug discrimination task with scopolamine. Male Wistar rats were trained to discriminate between scopolamine and saline administration using a two-lever discrimination task. Once discrimination was acquired, the subjects were divided into three independent groups, (1) control, (2) diazepam, and (3) diazepam chronic administration (10 days). Subsequently, generalization curves for scopolamine were obtained. Additionally, the diazepam and control groups were revaluated after 90 days without having been given any other treatment. The results showed that diazepam produced a significant reduction in the generalization gradient for scopolamine, indicating an impairment of discrimination. The negative effect of diazepam persisted even 90 days after drug had been administered. Meanwhile, the previous administration of diazepam for 10 days totally abated the generalization curve and the general performance of the subjects. The results suggest that diazepam affects memory for the stimulus discrimination of anticholinergic drugs and does so persistently, which could be an important consideration during the treatment of amnesic patients with benzodiazepines.
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Affiliation(s)
- C Casasola-Castro
- Departamento de Psicobiología y Neurociencias, Facultad de Psicología, Universidad Nacional Autónoma de México (UNAM), Av. Universidad 3004, Col. Copilco-Universidad, 04510, Mexico City, Mexico.
| | - L Weissmann-Sánchez
- Departamento de Psicobiología y Neurociencias, Facultad de Psicología, Universidad Nacional Autónoma de México (UNAM), Av. Universidad 3004, Col. Copilco-Universidad, 04510, Mexico City, Mexico
| | - E Calixto-González
- Departamento de Psicobiología y Neurociencias, Facultad de Psicología, Universidad Nacional Autónoma de México (UNAM), Av. Universidad 3004, Col. Copilco-Universidad, 04510, Mexico City, Mexico.,Departamento de Neurobiología, Dirección de Neurociencias, Instituto Nacional de Psiquiatría Ramón de la Fuente, México City, Mexico
| | - A Aguayo-Del Castillo
- Departamento de Psicobiología y Neurociencias, Facultad de Psicología, Universidad Nacional Autónoma de México (UNAM), Av. Universidad 3004, Col. Copilco-Universidad, 04510, Mexico City, Mexico
| | - D N Velázquez-Martínez
- Departamento de Psicobiología y Neurociencias, Facultad de Psicología, Universidad Nacional Autónoma de México (UNAM), Av. Universidad 3004, Col. Copilco-Universidad, 04510, Mexico City, Mexico
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Formation of GABA A receptor complexes containing α1 and α5 subunits is paralleling a multiple T-maze learning task in mice. Brain Struct Funct 2016; 222:549-561. [PMID: 27155990 DOI: 10.1007/s00429-016-1233-x] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2015] [Accepted: 04/28/2016] [Indexed: 10/21/2022]
Abstract
There is limited information on the role of GABA type A receptors (GABAARs) containing α1, α5 and γ2 subunits in learning and memory. Here, we assessed the possible role of such receptors in spatial learning using the multiple T-maze (MTM) paradigm. C57BL/6J mice were trained in the MTM which induced elevated levels of α1 and α5 subunit-containing hippocampal GABAAR complexes. Moreover, spatial learning evoked a significant increase in the colocalization of α1 and α5 subunits in both, CA1 and dentate gyrus regions of the hippocampus suggesting the formation of complexes containing both subunits. Additionally, the presence of α1, α5 and γ2 subunits in high molecular weight GABAARs was detected and significant correlation in the level of α1-containing complexes with those containing α5 and γ2 subunits was demonstrated. Accordingly, α1 deficiency led to decreased levels of γ2 subunit-containing complexes, however, had no effect on α5-containing ones. On the other hand, α1 knockout mice showed impaired performance in the MTM correlating with increased levels of α5 subunit-containing GABAARs in comparison to trained floxed control animals which quickly learned the task. Taken together, these results suggest that α1, α5 and γ2-containing hippocampal GABAAR complexes play an essential role in spatial learning and memory in which targeted disruption of the α1 subunit produces profound deficits.
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Insights into functional pharmacology of α₁ GABA(A) receptors: how much does partial activation at the benzodiazepine site matter? Psychopharmacology (Berl) 2013; 230:113-23. [PMID: 23685860 PMCID: PMC3795825 DOI: 10.1007/s00213-013-3143-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/04/2013] [Accepted: 04/29/2013] [Indexed: 01/09/2023]
Abstract
RATIONALE Synthesis of ligands inactive or with low activity at α₁ GABA(A) receptors has become the key concept for development of novel, more tolerable benzodiazepine (BZ)-like drugs. WYS8, a remarkably (105 times) α₁-subtype selective partial positive modulator, may serve as a pharmacological tool for refining the role of α₁ GABA(A) receptors in mediation of BZs' effects. OBJECTIVES Here, the effects of WYS8 on GABA-induced currents and on diazepam-induced potentiation of recombinant BZ-sensitive GABA(A) receptors were studied in more detail. In addition, the behavioral profile of WYS8 (0.2, 1, and 10 mg/kg i.p.), on its own and in combination with diazepam, was tested in the spontaneous locomotor activity, elevated plus maze, grip strength, rotarod, and pentylenetetrazole tests. RESULTS WYS8, applied at an in vivo attainable concentration of 100 nM, reduced the stimulation of GABA currents by 1 μM diazepam by 57 % at α₁β₃γ₂, but not at α₂β₃γ₂, α₃β₃γ₂, or α₅β₃γ₂ GABA(A) receptors. The administration of WYS8 alone induced negligible behavioral consequences. When combined with diazepam, WYS8 caused a reduction in sedation, muscle relaxation, and anticonvulsant activity, as compared with this BZ alone, whereas ataxia was preserved, and the anxiolytic effect of 2 mg/kg diazepam was unmasked. CONCLUSIONS Hence, a partial instead of full activation at α₁ GABA(A) receptors did not necessarily result in the attenuation of the effects assumed to be mediated by activation of these receptors, or in the full preservation of the effects mediated by activation of other GABA(A) receptors. Thus, the role of α₁ GABA(A) receptors appears more complex than that proposed by genetic studies.
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