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Soares C, Da Ros LU, Machado LS, Rocha A, Lazzarotto G, Carello-Collar G, De Bastiani MA, Ferrari-Souza JP, Lussier FZ, Souza DO, Rosa-Neto P, Pascoal TA, Bellaver B, Zimmer ER. The glutamatergic system in Alzheimer's disease: a systematic review with meta-analysis. Mol Psychiatry 2024:10.1038/s41380-024-02473-0. [PMID: 38366114 DOI: 10.1038/s41380-024-02473-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/17/2023] [Revised: 01/23/2024] [Accepted: 01/31/2024] [Indexed: 02/18/2024]
Abstract
Glutamatergic neurotransmission system dysregulation may play an important role in the pathophysiology of Alzheimer's disease (AD). However, reported results on glutamatergic components across brain regions are contradictory. Here, we conducted a systematic review with meta-analysis to examine whether there are consistent glutamatergic abnormalities in the human AD brain. We searched PubMed and Web of Science (database origin-October 2023) reports evaluating glutamate, glutamine, glutaminase, glutamine synthetase, glutamate reuptake, aspartate, excitatory amino acid transporters, vesicular glutamate transporters, glycine, D-serine, metabotropic and ionotropic glutamate receptors in the AD human brain (PROSPERO #CDRD42022299518). The studies were synthesized by outcome and brain region. We included cortical regions, the whole brain (cortical and subcortical regions combined), the entorhinal cortex and the hippocampus. Pooled effect sizes were determined with standardized mean differences (SMD), random effects adjusted by false discovery rate, and heterogeneity was examined by I2 statistics. The search retrieved 6 936 articles, 63 meeting the inclusion criteria (N = 709CN/786AD; mean age 75/79). We showed that the brain of AD individuals presents decreased glutamate (SMD = -0.82; I2 = 74.54%; P < 0.001) and aspartate levels (SMD = -0.64; I2 = 89.71%; P = 0.006), and reuptake (SMD = -0.75; I2 = 83.04%; P < 0.001. We also found reduced α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPAR)-GluA2/3 levels (SMD = -0.63; I2 = 95.55%; P = 0.046), hypofunctional N-methyl-D-aspartate receptor (NMDAR) (SMD = -0.60; I2 = 91.47%; P < 0.001) and selective reduction of NMDAR-GluN2B subunit levels (SMD = -1.07; I2 = 41.81%; P < 0.001). Regional differences include lower glutamate levels in cortical areas and aspartate levels in cortical areas and in the hippocampus, reduced glutamate reuptake, reduced AMPAR-GluA2/3 in the entorhinal cortex, hypofunction of NMDAR in cortical areas, and a decrease in NMDAR-GluN2B subunit levels in the entorhinal cortex and hippocampus. Other parameters studied were not altered. Our findings show depletion of the glutamatergic system and emphasize the importance of understanding glutamate-mediated neurotoxicity in AD. This study has implications for the development of therapies and biomarkers in AD.
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Affiliation(s)
- Carolina Soares
- Graduate Program in Biological Sciences: Biochemistry, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, Brazil
- Department of Psychiatry, University of Pittsburgh, Pittsburgh, PA, USA
| | - Lucas Uglione Da Ros
- Graduate Program in Biological Sciences: Biochemistry, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, Brazil
| | - Luiza Santos Machado
- Graduate Program in Biological Sciences: Biochemistry, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, Brazil
| | - Andreia Rocha
- Graduate Program in Biological Sciences: Biochemistry, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, Brazil
| | - Gabriela Lazzarotto
- Graduate Program in Biological Sciences: Biochemistry, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, Brazil
| | - Giovanna Carello-Collar
- Graduate Program in Biological Sciences: Biochemistry, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, Brazil
| | - Marco A De Bastiani
- Graduate Program in Biological Sciences: Pharmacology and Therapeutics, UFRGS, Porto Alegre, Brazil
| | - João Pedro Ferrari-Souza
- Graduate Program in Biological Sciences: Biochemistry, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, Brazil
- Department of Psychiatry, University of Pittsburgh, Pittsburgh, PA, USA
| | - Firoza Z Lussier
- Department of Psychiatry, University of Pittsburgh, Pittsburgh, PA, USA
| | - Diogo O Souza
- Graduate Program in Biological Sciences: Biochemistry, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, Brazil
- Department of Biochemistry, UFRGS, Porto Alegre, Brazil
| | - Pedro Rosa-Neto
- Translational Neuroimaging Laboratory, The McGill University Research Centre for Studies in Aging, McGill University, Montreal, QC, Canada
- Douglas Research Institute, Le Centre Intégré Universitaire de Santé et de Services Sociaux de l'Ouest-de-l'Île-de-Montréal, McGill University, Montreal, QC, Canada
- Department of Neurology and Neurosurgery, McGill University, Montreal, QC, Canada
- Department of Psychiatry, McGill University, Montreal, QC, Canada
| | - Tharick A Pascoal
- Department of Psychiatry, University of Pittsburgh, Pittsburgh, PA, USA
- Department of Neurology and Neurosurgery, McGill University, Montreal, QC, Canada
- Department of Neurology, University of Pittsburgh, Pittsburgh, PA, USA
| | - Bruna Bellaver
- Graduate Program in Biological Sciences: Biochemistry, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, Brazil
- Department of Psychiatry, University of Pittsburgh, Pittsburgh, PA, USA
| | - Eduardo R Zimmer
- Graduate Program in Biological Sciences: Biochemistry, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, Brazil.
- Graduate Program in Biological Sciences: Pharmacology and Therapeutics, UFRGS, Porto Alegre, Brazil.
- Department of Biochemistry, UFRGS, Porto Alegre, Brazil.
- Department of Neurology and Neurosurgery, McGill University, Montreal, QC, Canada.
- Brain Institute of Rio Grande do Sul - Pontifícia Universidade Católica do Rio Grande do Sul, Porto Alegre, Brazil.
- Department of Pharmacology, UFRGS, Porto Alegre, Brazil.
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Iova OM, Marin GE, Lazar I, Stanescu I, Dogaru G, Nicula CA, Bulboacă AE. Nitric Oxide/Nitric Oxide Synthase System in the Pathogenesis of Neurodegenerative Disorders-An Overview. Antioxidants (Basel) 2023; 12:antiox12030753. [PMID: 36979000 PMCID: PMC10045816 DOI: 10.3390/antiox12030753] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2023] [Revised: 02/24/2023] [Accepted: 03/15/2023] [Indexed: 03/30/2023] Open
Abstract
Nitric oxide, a ubiquitous molecule found throughout the natural world, is a key molecule implicated in many central and benefic molecular pathways and has a well-established role in the function of the central nervous system, as numerous studies have previously shown. Dysregulation of its metabolism, mainly the upregulation of nitric oxide production, has been proposed as a trigger and/or aggravator for many neurological affections. Increasing evidence supports the implication of this molecule in prevalent neurodegenerative diseases, such as Parkinson's disease, Alzheimer's disease, or amyotrophic lateral sclerosis. The mechanisms proposed for its neurotoxicity mainly center around the increased quantities of nitric oxide that are produced in the brain, their cause, and, most importantly, the pathological metabolic cascades created. These cascades lead to the formation of neuronal toxic substances that impair the neurons' function and structure on multiple levels. The purpose of this review is to present the main causes of increased pathological production, as well as the most important pathophysiological mechanisms triggered by nitric oxide, mechanisms that could help explain a part of the complex picture of neurodegenerative diseases and help develop targeted therapies.
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Affiliation(s)
- Olga-Maria Iova
- Faculty of Medicine, Iuliu Hatieganu University of Medicine and Pharmacy, 400349 Cluj-Napoca, Romania
| | - Gheorghe-Eduard Marin
- Faculty of Medicine, Iuliu Hatieganu University of Medicine and Pharmacy, 400349 Cluj-Napoca, Romania
| | - Izabella Lazar
- Faculty of Medicine, Iuliu Hatieganu University of Medicine and Pharmacy, 400349 Cluj-Napoca, Romania
| | - Ioana Stanescu
- Department of Neurology, Iuliu Haţieganu University of Medicine and Pharmacy, 400012 Cluj-Napoca, Romania
| | - Gabriela Dogaru
- Department of Physical Medicine and Rehabilitation, Iuliu Haţieganu University of Medicine and Pharmacy Cluj-Napoca, Viilor Street, No. 46-50, 400347 Cluj-Napoca, Romania
| | - Cristina Ariadna Nicula
- Department of Ophthalmology, Iuliu Hațieganu University of Medicine and Pharmacy, 400012 Cluj-Napoca, Romania
| | - Adriana Elena Bulboacă
- Department of Pathophysiology, Iuliu Hațieganu University of Medicine and Pharmacy, 400012 Cluj-Napoca, Romania
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3
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Getting to NO Alzheimer's Disease: Neuroprotection versus Neurotoxicity Mediated by Nitric Oxide. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2015; 2016:3806157. [PMID: 26697132 PMCID: PMC4677236 DOI: 10.1155/2016/3806157] [Citation(s) in RCA: 91] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 07/03/2015] [Accepted: 08/16/2015] [Indexed: 12/20/2022]
Abstract
Alzheimer's disease (AD) is a neurodegenerative disorder involving the loss of neurons in the brain which leads to progressive memory loss and behavioral changes. To date, there are only limited medications for AD and no known cure. Nitric oxide (NO) has long been considered part of the neurotoxic insult caused by neuroinflammation in the Alzheimer's brain. However, focusing on early developments, prior to the appearance of cognitive symptoms, is changing that perception. This has highlighted a compensatory, neuroprotective role for NO that protects synapses by increasing neuronal excitability. A potential mechanism for augmentation of excitability by NO is via modulation of voltage-gated potassium channel activity (Kv7 and Kv2). Identification of the ionic mechanisms and signaling pathways that mediate this protection is an important next step for the field. Harnessing the protective role of NO and related signaling pathways could provide a therapeutic avenue that prevents synapse loss early in disease.
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Rodrigues R, Petersen RB, Perry G. Parallels between major depressive disorder and Alzheimer's disease: role of oxidative stress and genetic vulnerability. Cell Mol Neurobiol 2014; 34:925-49. [PMID: 24927694 DOI: 10.1007/s10571-014-0074-5] [Citation(s) in RCA: 64] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2014] [Accepted: 05/14/2014] [Indexed: 12/19/2022]
Abstract
The thesis of this review is that oxidative stress is the central factor in major depressive disorder (MDD) and Alzheimer's disease (AD). The major elements involved are inflammatory cytokines, the hypothalamic-pituitary axis, the hypothalamic-pituitary gonadal, and arginine vasopressin systems, which induce glucocorticoid and "oxidopamatergic" cascades when triggered by psychosocial stress, severe life-threatening events, and mental-affective and somatic diseases. In individuals with a genomic vulnerability to depression, these cascades may result in chronic depression-anxiety-stress spectra, resulting in MDD and other known depressive syndromes. In contrast, in subjects with genomic vulnerability to AD, oxidative stress-induced brain damage triggers specific antioxidant defenses, i.e., increased levels of amyloid-β (Aβ) and aggregation of hyper-phosphorylated tau, resulting in paired helical filaments and impaired functions related to the ApoEε4 isoform, leading to complex pathological cascades culminating in AD. Surprisingly, all the AD-associated molecular pathways mentioned in this review have been shown to be similar or analogous to those found in depression, including structural damage, i.e., hippocampal and frontal cortex atrophy. Other interacting molecular signals, i.e., GSK-3β, convergent survival factors (brain-derived neurotrophic factor and heat shock proteins), and transition redox metals are also mentioned to emphasize the vast array of intermediates that could interact via comparable mechanisms in both MDD and AD.
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Affiliation(s)
- Roberto Rodrigues
- College of Sciences, The University of Texas at San Antonio, One UTSA Circle, San Antonio, TX, 78249, USA,
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Lin CLG, Kong Q, Cuny GD, Glicksman MA. Glutamate transporter EAAT2: a new target for the treatment of neurodegenerative diseases. Future Med Chem 2012; 4:1689-700. [PMID: 22924507 PMCID: PMC3580837 DOI: 10.4155/fmc.12.122] [Citation(s) in RCA: 88] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Glutamate is the primary excitatory amino acid neurotransmitter in the CNS. The concentration of glutamate in the synaptic cleft is tightly controlled by interplay between glutamate release and glutamate clearance. Abnormal glutamate release and/or dysfunction of glutamate clearance can cause overstimulation of glutamate receptors and result in neuronal injury known as excitotoxicity. The glial glutamate transporter EAAT2 plays a major role in glutamate clearance. Dysfunction or reduced expression of EAAT2 has been documented in many neurodegenerative diseases. In addition, many studies in animal models of disease indicate that increased EAAT2 expression provides neuronal protection. Here, we summarize these studies and suggest that EAAT2 is a potential target for the prevention of excitotoxicity. EAAT2 can be upregulated by transcriptional or translational activation. We discuss current progress in the search for EAAT2 activators, which is a promising direction for the treatment of neurodegenerative diseases.
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Vandesquille M, Carrié I, Louis C, Beracochea D, Lestage P. Effects of positive modulators of α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA)-type glutamate receptors in a benzodiazepine-induced deficit of spatial discrimination in mice. J Psychopharmacol 2012; 26:845-56. [PMID: 21890586 DOI: 10.1177/0269881111416692] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Imbalance between GABAergic and glutamatergic neurotransmission has been recently hypothesized to trigger memory decline related either to ageing or to Alzheimer's disease (AD). Thereby, benzodiazepine-induced anterograde amnesia has been construed as a model of hippocampal-related cognitive dysfunctions. Since spatial memory is altered both by ageing and by benzodiazepines such as alprazolam, we investigated the pharmacological sensitivity of alprazolam-induced deficit in a delayed spatial discrimination (SD) task, notably with positive allosteric modulators of α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA)-type glutamate receptors. We showed that alprazolam (0.1 mg/kg intraperitoneally) induced memory impairments as compared with vehicle-treated mice. The oral administration of modulators of AMPA receptors (IDRA-21: 10 mg/kg; S18986: 3 and 10 mg/kg) reversed the alprazolam-induced deficits. This study is first to show evidence that reference treatments of AD, such as memantine (a NMDA receptor antagonist) at 3 mg/kg per os (po) and donepezil (an acetylcholinesterase inhibitor) at 1 mg/kg po, also reversed the alprazolam-induced amnesia. Given such results, the SD task emerges as a valuable novel task to screen pro-cognitive compounds. Thus, we highlight the efficacy of modulators of AMPA-type glutamate receptors to counteract alprazolam-induced spatial deficits. These results could be viewed alongside the imbalance between excitation and inhibition observed during normal and pathological ageing.
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Affiliation(s)
- M Vandesquille
- Institut de Recherches Servier, Croissy-sur-Seine, France.
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7
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Abstract
Glutamate receptors are key mediators of brain communication. Among ionotropic glutamate receptors, kainate receptors (KARs) have been least explored and their relevance to pathophysiology is relatively obscure. This is in part due to the relatively low abundance of KARs, the regulatory function in network activity they play, the lack of specific agonists and antagonists for this receptor subtype, as well as to the absence of striking phenotypes in mice deficient in KAR subunits. Nonetheless, it is now well established that KARs are located presynaptically whereby they regulate glutamate and GABA release, and thus, excitability and participate in short‐term plasticity. In turn, KARs are also located postsynaptically and their activation contributes to synaptic integration. The development of specific novel ligands is helping to further investigate the contribution of KARs to health and disease. In this review, I summarize current knowledge about KAR physiology and pharmacology, and discuss their involvement in cell death and disease. In addition, I recapitulate the available data about the use of KAR antagonists and receptor subunit deficient mice in experimental paradigms of brain diseases, as well as the main findings about KAR roles in human CNS disorders. In sum, subunit specific antagonists have therapeutic potential in neurodegenerative and psychiatric diseases as well as in epilepsy and pain. Knowledge about the genetics of KARs will also help to understand the pathophysiology of those and other illnesses.
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Affiliation(s)
- Carlos Matute
- Centro de Investigación Biomédica en Red en Enfermedades Neurodegenerativas (CIBERNED) and Departamento de Neurociencias, Universidad del País Vasco, 48940-Leioa, Spain.
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8
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Tian G, Kong Q, Lai L, Ray-Chaudhury A, Lin CLG. Increased expression of cholesterol 24S-hydroxylase results in disruption of glial glutamate transporter EAAT2 association with lipid rafts: a potential role in Alzheimer's disease. J Neurochem 2010; 113:978-89. [PMID: 20193040 DOI: 10.1111/j.1471-4159.2010.06661.x] [Citation(s) in RCA: 65] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The glial glutamate transporter EAAT2 (excitatory amino acid transporter 2) is the major mediator of glutamate clearance that terminates glutamate-mediated neurotransmission. Loss of EAAT2 and associated glutamate uptake function has been reported in the brains of patients with Alzheimer's disease (AD). We previously reported that EAAT2 is associated with lipid raft microdomains of the plasma membrane. In the present study, we demonstrated that association of EAAT2 with lipid rafts is disrupted in AD brains. This abnormality is not a consequence of neuron degeneration, oxidative stress, or amyloid beta toxicity. In AD brains, cholesterol 24S-hydroxylase (CYP46), a key enzyme in maintenance of cholesterol homeostasis in the brain, is markedly increased in astrocytes but decreased in neurons. We demonstrated that increased expression of CYP46 in primary astrocytes results in a reduction of membrane cholesterol levels and leads to the dissociation of EAAT2 from lipid rafts and the loss of EAAT2 and associated glutamate uptake function. These results suggest that a disturbance of cholesterol metabolism may contribute to loss of EAAT2 in AD.
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Affiliation(s)
- Guilian Tian
- Department of Neuroscience, The Ohio State University, Columbus, Ohio 43210, USA
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9
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Agarwal KN. Iron and the brain: neurotransmitter receptors and magnetic resonance spectroscopy. Br J Nutr 2007. [DOI: 10.1079/bjn2000307] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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10
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Rekart JL, Quinn B, Mesulam MM, Routtenberg A. Subfield-specific increase in brain growth protein in postmortem hippocampus of Alzheimer's patients. Neuroscience 2004; 126:579-84. [PMID: 15183507 DOI: 10.1016/j.neuroscience.2004.03.060] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/07/2004] [Indexed: 10/26/2022]
Abstract
The neuropathology of Alzheimer's disease (AD) reflects a precarious balance between neurodegenerative phenomena and reactive events of neuroplasticity. This latter aspect of AD neuropathology has received less attention than it deserves and its contribution to memory loss is therefore not well understood. To monitor neuroplastic-related events we studied the distribution of the plasticity-associated, brain growth protein GAP-43 in AD subjects and age-matched controls. In tissue from AD patients, we observed a consistent elevation of GAP-43 in a subfield of the hippocampus, stratum lacunosum moleculare. This subfield contains inputs from multiple brain regions and is known to regulate declarative memory function. Levels of potentially aberrant sprouting, as marked by elevated growth protein, were positively correlated with the severity of AD suggesting that increased expression of GAP-43 leads to a miswiring of circuits critical for memory function. Our findings suggest a mechanism, aberrant neuroplasticity, that in concert with neurodegeneration may importantly contribute to the memory loss in AD.
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Affiliation(s)
- J L Rekart
- Department of Psychology, Northwestern University, Evanston, IL 60208, USA
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11
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Mittal RD, Pandey A, Mittal B, Agarwal KN. Effect of latent iron deficiency on GABA and glutamate neuroreceptors in rat brain. Indian J Clin Biochem 2003; 18:111-6. [PMID: 23105383 PMCID: PMC3453737 DOI: 10.1007/bf02867677] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Eight weeks of latent iron deficiency in weaned female rats of Sprague Dawley strain maintained on experimental low-iron diet (18-20 mg/kg) did not significantly change the gross body, weight and tissue weights of brain and liver. Packed cell volume (PCV) and hemoglobin concentration remained unaltered. However, non-heme iron content in liver and brain decreased significantly (p<0.001). The activities of glutamate dehydrogenase, glutamic acid decarboxylase, and GABA-transaminase (GABA-T) in brain decreased by 15%, 11.4% and 25.7% respectively. However, this decrease was not statistically significant. Binding of(3)H Muscimol at pH 7.5 and 1 mg protein/assay increased by 143% (p<0.001) in synaptic vesicular membranes from iron-deficient rats as compared to the controls.(3)H glutamate binding to the synaptic vesicles was also carried out under similar condition. However, the L-glutamate binding was reduced by 63% in the vesicular membranes of iron deficient animals. These studies indicate that iron plays important functional role in both excitatory and inhibitory neurotransmitter receptors.
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Affiliation(s)
- Rama Devi Mittal
- Department of Biochemistry, Sanjay Gandhi Post Graduate Institute of Medical Sciences, 226014 Lucknow, India
| | - Amita Pandey
- Department of Biochemistry, Sanjay Gandhi Post Graduate Institute of Medical Sciences, 226014 Lucknow, India
- Department of Genetics, Sanjay Gandhi Post Graduate Institute of Medical Sciences, 226014 Lucknow, India
- Dept. of Urology, Sanjay Gandhi Post Graduate Institute of Medical Sciences, 226014 Lucknow, India
| | - Balraj Mittal
- Department of Genetics, Sanjay Gandhi Post Graduate Institute of Medical Sciences, 226014 Lucknow, India
| | - Kailash Nath Agarwal
- Department of Biochemistry, Sanjay Gandhi Post Graduate Institute of Medical Sciences, 226014 Lucknow, India
- Department of Genetics, Sanjay Gandhi Post Graduate Institute of Medical Sciences, 226014 Lucknow, India
- Dept. of Urology, Sanjay Gandhi Post Graduate Institute of Medical Sciences, 226014 Lucknow, India
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12
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Tran MH, Yamada K, Nabeshima T. Amyloid beta-peptide induces cholinergic dysfunction and cognitive deficits: a minireview. Peptides 2002; 23:1271-83. [PMID: 12128084 DOI: 10.1016/s0196-9781(02)00062-1] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Amyloid beta-peptide (Abeta) plays a critical role in the development of Alzheimer's disease (AD). Much progress has been made in understanding this age-related neurodegenerative disorder, thus an insight into the cellular actions of Abeta and resulting functional consequences may contribute to preventive and therapeutic approaches for AD. In this review, recent evidence of Abeta-induced brain dysfunction, particularly of cholinergic impairment and memory deficits is summarized. Moreover, proposed mechanisms for Abeta-induced neurotoxicity such as oxidative stress, ion-channel formation, and Abeta-receptor interaction are discussed.
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Affiliation(s)
- Manh Hung Tran
- Department of Neuropsychopharmacology and Hospital Pharmacy, Nagoya University Graduate School of Medicine, Nagoya 466-8560, Japan
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13
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Mittal RD, Pandey A, Mittal B, Agarwal KN. Effect of latent iron deficiency on gaba and glutamate neuroreceptors in rat brain. Indian J Clin Biochem 2002; 17:1-6. [PMID: 23105345 PMCID: PMC3454128 DOI: 10.1007/bf02867966] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
Eight weeks of latent iron deficiency in weaned female rats of Sprague Dawley strain maintained on experimental low-iron diet (18-20 mg/Kg) did not significantly change the gross body weight and tissue weights of brain and liver. Packed cell volume (PCV) and hemoglobin concentration remained unaltered. However, non-heme iron content in liver and brain decreased significantly (P<0.001). The activities of glutamate dehydrogenase, glutamic acid decarboxylase, and GABA-transaminase (GABA-T) in brain decreased by 15%, 11.4% and 25.7% respectively. However, this decrease was not statistically significant. Binding of(3)H Muscimol at pH 7.5 and 1 mg protein/assay increased by 143% (P<0.001) in synaptic vesicular membranes from iron-deficient rats as compared to the controls.(3)H glutamate binding to the synaptic vesicles was also carried out under similar condition. However, the L-glutamate binding was reduced by 63% in the vesicular membranes of iron deficient animals. These studies in dicate that iron plays an important functional role in both excitatory and inhibitory neurotransmitter receptors.
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Affiliation(s)
- Rama Devi Mittal
- Department of Biochemistry, Sanjay Gandhi Post Graduate Institute of Medical Sciences, 226014 Lucknow, India
| | - Amita Pandey
- Department of Genetics, Sanjay Gandhi Post Graduate Institute of Medical Sciences, 226014 Lucknow, India
| | - Balraj Mittal
- Department of Genetics, Sanjay Gandhi Post Graduate Institute of Medical Sciences, 226014 Lucknow, India
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14
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Ragnarsson L, Mortensen M, Dodd PR, Lewis RJ. Spermine modulation of the glutamate(NMDA) receptor is differentially responsive to conantokins in normal and Alzheimer's disease human cerebral cortex. J Neurochem 2002; 81:765-79. [PMID: 12065636 DOI: 10.1046/j.1471-4159.2002.00872.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The pharmacology of the N -methyl-d-aspartate (NMDA) receptor site was examined in pathologically affected and relatively spared regions of cerebral cortex tissue obtained at autopsy from Alzheimer's disease cases and matched controls. The affinity and density of the [(3)H]MK-801 binding site were delineated along with the enhancement of [(3)H]MK-801 binding by glutamate and spermine. Maximal enhancement induced by either ligand was regionally variable; glutamate-mediated maximal enhancement was higher in controls than in Alzheimer's cases in pathologically spared regions, whereas spermine-mediated maximal enhancement was higher in controls in areas susceptible to pathological damage. These and other data suggest that the subunit composition of NMDA receptors may be locally variable. Studies with modified conantokin-G (con-G) peptides showed that Ala(7)-con-G had higher affinity than Lys(7)-con-G, and also defined two distinct binding sites in controls. Nevertheless, the affinity for Lys(7)-con-G was higher overall in Alzheimer's brain than in control brain, whereas the reverse was true for Ala(7)-con-G. Over-excitation mediated by specific NMDA receptors might contribute to localized brain damage in Alzheimer's disease. Modified conantokins are useful for identifying the NMDA receptors involved, and may have potential as protective agents.
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Affiliation(s)
- Lotten Ragnarsson
- Department of Biochemistry, University of Queensland, Brisbane 4072, Australia
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15
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Abstract
Ensaculin, a novel benzopyranone substituted with a piperazine moiety, showed memory-enhancing effects in paradigms of passive and conditioned avoidance in both normal and artificially amnesic rodents. It exhibited neuroprotective activities in an NMDA toxicity model and neurotrophic effects in primary cultured rat brain cells. The compound could be characterized as a weak NMDA receptor-operated channel blocker. In receptor-binding studies, ensaculin was found to have high affinities to serotonergic 5-HT(1A) and 5-HT(7) receptors, adrenergic alpha(1), and dopaminergic D(2) and D(3) receptors. Due to its unique pharmacodynamic profile, ensaculin may have potential as an antidementia agent acting on various transmitter systems.
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Affiliation(s)
- Robert Hoerr
- Clinical Research Department, Dr. Willmar Schwabe GmbH Co., Karlsruhe, Germany.
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16
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Abstract
Brain tissue has a remarkable ability to accumulate glutamate. This ability is due to glutamate transporter proteins present in the plasma membranes of both glial cells and neurons. The transporter proteins represent the only (significant) mechanism for removal of glutamate from the extracellular fluid and their importance for the long-term maintenance of low and non-toxic concentrations of glutamate is now well documented. In addition to this simple, but essential glutamate removal role, the glutamate transporters appear to have more sophisticated functions in the modulation of neurotransmission. They may modify the time course of synaptic events, the extent and pattern of activation and desensitization of receptors outside the synaptic cleft and at neighboring synapses (intersynaptic cross-talk). Further, the glutamate transporters provide glutamate for synthesis of e.g. GABA, glutathione and protein, and for energy production. They also play roles in peripheral organs and tissues (e.g. bone, heart, intestine, kidneys, pancreas and placenta). Glutamate uptake appears to be modulated on virtually all possible levels, i.e. DNA transcription, mRNA splicing and degradation, protein synthesis and targeting, and actual amino acid transport activity and associated ion channel activities. A variety of soluble compounds (e.g. glutamate, cytokines and growth factors) influence glutamate transporter expression and activities. Neither the normal functioning of glutamatergic synapses nor the pathogenesis of major neurological diseases (e.g. cerebral ischemia, hypoglycemia, amyotrophic lateral sclerosis, Alzheimer's disease, traumatic brain injury, epilepsy and schizophrenia) as well as non-neurological diseases (e.g. osteoporosis) can be properly understood unless more is learned about these transporter proteins. Like glutamate itself, glutamate transporters are somehow involved in almost all aspects of normal and abnormal brain activity.
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Affiliation(s)
- N C Danbolt
- Department of Anatomy, Institute of Basic Medical Sciences, University of Oslo, P.O. Box 1105, Blindern, N-0317, Oslo, Norway
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17
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Lancelot E, Beal MF. Glutamate toxicity in chronic neurodegenerative disease. PROGRESS IN BRAIN RESEARCH 1999; 116:331-47. [PMID: 9932386 DOI: 10.1016/s0079-6123(08)60446-x] [Citation(s) in RCA: 90] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/02/2022]
Affiliation(s)
- E Lancelot
- Department of Neurology, Massachusetts General Hospital, Boston 02114, USA
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18
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Beckstrøm H, Julsrud L, Haugeto O, Dewar D, Graham DI, Lehre KP, Storm-Mathisen J, Danbolt NC. Interindividual differences in the levels of the glutamate transporters GLAST and GLT, but no clear correlation with Alzheimer's disease. J Neurosci Res 1999; 55:218-29. [PMID: 9972824 DOI: 10.1002/(sici)1097-4547(19990115)55:2<218::aid-jnr9>3.0.co;2-l] [Citation(s) in RCA: 74] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Alzheimer's disease is a common progressive neurodegenerative disease of unknown etiology. Several different pathological processes have been identified in the brains of Alzheimer patients. To determine if reduced glutamate uptake is a contributing factor, we have measured the levels of the glutamate transporter proteins GLAST (EAAT1) and GLT (EAAT2) in human autopsy samples. The postmortem proteolysis of these proteins turned out to be fairly rapid. Brains from 10 Alzheimer and 10 control patients were therefore obtained with a relatively short postmortem delay (5 hr on average). GLT (N-terminal and central parts), GLAST (C-terminal), glial fibrillary acidic protein (GFAP) and inositol (1,4,5)-triphosphate (IP3)-receptor immunoreactivities were determined in the cingulate and inferior temporal gyri by immunoblotting. The Na+-dependent "binding" of D-[3H]aspartate and the glutamate uptake after solubilization and reconstitution in liposomes were determined for comparison. An individual variation in GLAST and GLT levels was found, but no significant correlation with Alzheimer's disease, except for a 14% lower ratio of N-terminal to central GLT immunoreactivity (P < 0.04). The levels of GLAST and GLT showed negative correlation in agreement with the idea that these proteins are differentially regulated. In conclusion, Alzheimer's disease brains can have both normal and reduced levels of GLAST and GLT.
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Affiliation(s)
- H Beckstrøm
- Department of Anatomy, Institute of Basic Medical Sciences, University of Oslo, Norway
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19
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Glutamate Receptors and Excitotoxic Mechanisms in Alzheimer’s Disease. Cereb Cortex 1999. [DOI: 10.1007/978-1-4615-4885-0_18] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022] Open
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20
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Francis PT, Bowen DM. Neuronal pathology in relation to molecular biology and treatment of Alzheimer's disease. MOLECULAR AND CELL BIOLOGY OF HUMAN DISEASES SERIES 1998; 4:25-54. [PMID: 9439743 DOI: 10.1007/978-94-011-0709-9_2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Affiliation(s)
- P T Francis
- Miriam Marks Department of Neurochemistry, Institute of Neurology, London, UK
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21
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Rossner S. Cholinergic immunolesions by 192IgG-saporin--useful tool to simulate pathogenic aspects of Alzheimer's disease. Int J Dev Neurosci 1997; 15:835-50. [PMID: 9568532 DOI: 10.1016/s0736-5748(97)00035-x] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Alzheimer's disease, the most common cause of senile dementia, is characterized by intracellular formation of neurofibrillary tangles, extracellular deposits of beta amyloid as well as cerebrovascular amyloid accumulation and a profound loss of cholinergic neurons within the nucleus basalis Meynert with alterations in cortical neurotransmitter receptor densities. The use of the cholinergic immunotoxin 192IgG-saporin allows for the first time study of the impact of cortical cholinergic deafferentation on cortical neurotransmission, learning, and memory without direct effects on other neuronal systems. This model also allows the elucidation of contributions of cholinergic mechanisms to the establishment of other pathological features of Alzheimer's disease. The findings discussed here demonstrate that cholinergic immunolesions by 192IgG-saporin induce highly specific, permanent cortical cholinergic hypoactivity and alterations in cortical neurotransmitter densities comparable to those described for Alzheimer's disease. The induced cortical cholinergic deficit also leads to cortical/hippocampal neurotrophin accumulation and reduced amyloid precursor protein (APP) secretion, possibly reflecting the lack of stimulation of postsynaptic M1/M3 muscarinic receptors coupled to protein kinase C. This immunolesion model should prove useful to test therapeutic strategies based on stimulation of cortical cholinergic neurotransmission or amelioration of pathogenic aspects of cholinergic degeneration in the basal forebrain. Application of the model to animal species that can develop beta-amyloid plaques could provide information about the contribution of cholinergic function to amyloidogenic APP processing.
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Affiliation(s)
- S Rossner
- Paul Flechsig Institute for Brain Research, Department of Neurochemistry, University of Leipzig, Germany.
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22
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Weinstock M. Possible role of the cholinergic system and disease models. JOURNAL OF NEURAL TRANSMISSION. SUPPLEMENTUM 1997; 49:93-102. [PMID: 9266418 DOI: 10.1007/978-3-7091-6844-8_10] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Memory impairment associated with the loss of cortical cholinergic neurons in AD has stimulated the development of animal models based on blockade or destruction of these systems. Strategies include mechanical lesions, local injection of excitotoxic amino acids or ethylcholine aziridinium (AF 64A), which disrupt reference and working memory in rats, but lack specificity for cholinergic systems. Other models involving, reduction in cerebral blood flow and interference with oxidative metabolism of glucose, mimic those found in AD, and also interfere with working and long-term memory in the rat. Memory impairments can be reversed by acetylcholinesterase inhibitors and cholinergic agonists but beneficial effects of these agents in AD patients are small and inconsistent. This may be partly due to unfavorable pharmacokinetics and dose-limiting side effects of existing drugs. Newer, brain specific acetylcholinesterase inhibitors and M1 muscarinic agonists with a lower incidence of unwanted effects are currently being evaluated.
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Affiliation(s)
- M Weinstock
- Department of Pharmacology, School of Pharmacy, Hebrew University Hadassah Medical Centre, Jerusalem, Israel
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23
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Hiller JM, Fan LQ. Laminar distribution of the multiple opioid receptors in the human cerebral cortex. Neurochem Res 1996; 21:1333-45. [PMID: 8947923 DOI: 10.1007/bf02532374] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Quantitative autoradiographic assessment of cerebral cortical laminar distribution of mu, delta and kappa opioid receptors was carried out in coronal sections of five post-mortem human brains obtained at autopsy. The cortical areas studied were: cingulate, frontal, insular, parietal, parahippocampal, temporal, occipitotemporal, occipital and striate area. In general, the laminar patterns of distribution for the three types of receptors are distinctive. Peak levels of delta opioid binding are in laminae I, II, and IIIa. mu-Receptors are located in lamina III followed by I and II in cingulate, frontal, insular and parietal cortices and lamina IV in temporal and occiptotemporal cortices. kappa-Receptors are found concentrated in laminae V and VI. The patterns of opioid binding in cortical laminae showed remarkable consistency in all five brains examined. In contrast to other cortical areas, the parahippocampal gyrus, at the level of the amygdaloid formation, demonstrated peak kappa receptor density in laminae I, II and III. mu-Opioid binding was undetectable in the lateral occipital cortex and in the striate area.
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MESH Headings
- Aged
- Aged, 80 and over
- Analgesics/metabolism
- Autoradiography
- Benzomorphans/metabolism
- Cerebral Cortex/metabolism
- Cerebral Cortex/pathology
- Enkephalin, Ala(2)-MePhe(4)-Gly(5)-
- Enkephalin, Leucine/analogs & derivatives
- Enkephalin, Leucine/metabolism
- Enkephalins/metabolism
- Female
- Humans
- Male
- Organ Specificity
- Postmortem Changes
- Receptors, Opioid, delta/analysis
- Receptors, Opioid, delta/metabolism
- Receptors, Opioid, kappa/analysis
- Receptors, Opioid, kappa/metabolism
- Receptors, Opioid, mu/analysis
- Receptors, Opioid, mu/metabolism
- Tritium
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Affiliation(s)
- J M Hiller
- Department of Psychiatry New York University Medical Center, NY 10016, USA
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24
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Toth E. Effect of nicotine on the level of extracellular amino acids in the hippocampus of rat. Neurochem Res 1996; 21:903-7. [PMID: 8895843 DOI: 10.1007/bf02532339] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Using microdialysis, we compared intracerebral and subcutaneous administration of nicotine for the effect on the levels of extracellular amino acids in the hippocampus of anesthetized rats. Administration by microdialysis of 10 mM nicotine, resulting in a nicotine concentration of 0.134 mumol/g in the hippocampus, increased the extracellular levels of aspartic acid, glutamic acid, and serine by 26-60%. At 50 mM nicotine the increases in the levels of aspartic acid, glutamic acid, serine, glycine, and glutamine were between 76% and 141%. Subcutaneous administration of nicotine at a dose of 6 mumol/kg caused a 57% increase in the extracellular level of glutamic acid. After a dose of 12 mumol/kg that resulted in a nicotine level of 0.015 mumol/kg in the hippocampus, the extracellular level of glutamic acid was increased by 100%, and that of aspartic acid by 24%. Thus, higher cerebral nicotine levels were needed with intracerebral than with subcutaneous administration to obtain similar amino acid changes. Prior administration of mecamylamine or L-kynurenine prevented the subcutaneous nicotine-induced elevation of the extracellular levels of aspartic acid and glutamic acid. Our results indicate that receptor interactions modulate nicotine effects and that both nicotinic cholinergic and NMDA/glycine glutamatergic receptors participate in the action of nicotine in increasing extracellular amino acid levels.
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Affiliation(s)
- E Toth
- Nathan S. Kline Institute for Psychiatric Research, Center for Neurochemistry, Orangeburg, New York 10962, USA
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25
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Vidal C. Nicotinic receptors in the brain. Molecular biology, function, and therapeutics. MOLECULAR AND CHEMICAL NEUROPATHOLOGY 1996; 28:3-11. [PMID: 8871936 DOI: 10.1007/bf02815199] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Although the psychological and physiological effects of nicotine have long suggested that nicotine exerts specific actions in the brain, the identification of neuronal nicotinic receptors (nAChRs) only began in the past few years with the development of molecular genetics. It is now clear that neuronal nAChRs form a family of highly heterogenous receptor subtypes, as evidenced by the number of genes encoding nAChR subunits, the diversity of immunopurified receptor proteins, and the multiple functional types of ligand-gated ion channels. Neuronal nAChRs have discrete localizations within the brain, and are involved in modulating neuronal firing and transmitter release. Cumulative evidence from animal and human studies indicates that nicotinic systems play a major role in higher cognitive functions and dysfunctions. In particular, the loss of cortical nAChRs is a neuro-chemical hallmark of Alzheimer (AD) and Parkinson (PD) diseases. In addition, nicotine improves memory and attention in Ad and PD. Our recent studies using electrophysiological biochemical and behavioral approaches suggest that the prefrontal cortex is a major target site for the cognitive actions of nicotine.
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Affiliation(s)
- C Vidal
- Institut Pasteur, Paris, France
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26
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Wilcock GK, Harrold PL. Treatment of Alzheimer's disease: future directions. ACTA NEUROLOGICA SCANDINAVICA. SUPPLEMENTUM 1996; 165:128-36. [PMID: 8741000 DOI: 10.1111/j.1600-0404.1996.tb05883.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Following the introduction of tacrine hydrochloride (Cognex) in the United States and several other countries, researchers are pursuing two broad therapeutic strategies for Alzheimer's disease (AD). The first involves identifying agents or combinations of agents whose actions can compensate for the considerable cerebral damage that has typically occurred by the time the diagnosis of AD is made. Such therapeutic approaches include the development of additional cholinesterase inhibitors, agents that work on the receptors of other systems damaged by the disease process, and anti-inflammatory and immunomodulatory agents. The second and ultimately more promising strategy involves the development of approaches to retard, halt, or even prevent disease progression. Such protective approaches, which depend on the development of more effective methods for predicting and diagnosing AD, include the administration of nerve growth factor and other neurotrophins and the use of pharmacologic or genetic interventions to limit amyloid deposition and the formation of neurofibrillary tangles.
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Affiliation(s)
- G K Wilcock
- Department of Care of the Elderly, Frenchay Hospital, Bristol, England
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27
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D'Souza DC, Charney D, Krystal J. Glycine Site Agonists of the NMDA Receptor: A Review. CNS DRUG REVIEWS 1995. [DOI: 10.1111/j.1527-3458.1995.tb00285.x] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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28
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Ikonomovic MD, Sheffield R, Armstrong DM. AMPA-selective glutamate receptor subtype immunoreactivity in the hippocampal formation of patients with Alzheimer's disease. Hippocampus 1995; 5:469-86. [PMID: 8773259 DOI: 10.1002/hipo.450050509] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Immunocytochemical techniques were employed in order to examine the distribution and relative intensity of the AMPA receptor subunits GluR1 and GluR2/3 within the hippocampal formation of normal controls and Alzheimer's disease (AD) cases. Throughout our investigation we examined cases exhibiting a wide range of pathologic severity, thus allowing us to correlate our immunohistochemical data with the extent of pathology. Specifically, we investigated the distribution of these receptor subunits in hippocampal sectors that are particularly vulnerable to AD pathology (i.e., CA1 and subiculum) and compared these findings with those obtained following examination of sectors that are generally resistant to pathologic change (i.e., CA2/3, dentate gyrus). Within vulnerable sectors we observed a variable loss of GluR1 and GluR2/3 immunolabeling. The degree to which these proteins were reduced appeared to correlate with the extent of neurofibrillary pathology and cell loss. Despite the loss of labeled cells, the intensity of immunolabeling within the remaining neurons was comparable with, and in many instances even greater than, that observed in control cases. Within resistant sectors, the distribution of immunoreactive elements was comparable in both case groups yet the intensity of immunolabeling was markedly increased in AD cases, particularly in the molecular layer of the dentate gyrus and in the stratum lucidum of CA3 (i.e., the termination zones of perforant pathway and mossy fibers). In addition, within AD cases dramatic increases were observed within the supragranular and polymorphic layer of the dentate gyrus (i.e., the terminal zones of sprouting mossy fiber collaterals). The increase in GluR1 and GluR2/3 immunolabeling is hypothesized to occur in response to the deafferentation of selected glutamatergic pathways. Moreover, our data support that hippocampal plasticity is preserved, even in severe AD cases, and suggest a critical role for AMPA receptor subunits in this plasticity and in maintaining hippocampal functioning.
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Affiliation(s)
- M D Ikonomovic
- Neurosciences Research Center, Allegheny-Singer Research Institute, Allegheny General Hospital, Pittsburgh, Pennsylvania 15212-9986, USA
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29
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Abstract
Recent advances in neuroscience and molecular neurochemistry have substantially increased the knowledge of the neuropathobiology of senile dementia and Alzheimer's disease. On the basis of various hypotheses concerning degenerative processes in aging brains, new therapeutic strategies have been developed, including nootropic drugs with different mechanisms of action and heterogenous chemical structures. Mutual relationships exist between neuroscientific research and nootropic drug development. To date, such areas of research and drug development have involved deficits of brain neurotransmission (cholinergic, monoaminergic, peptidergic), free radical-induced damage, disturbances of calcium homeostasis and excitatory amino acid function, and deposition of amyloid protein.
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Affiliation(s)
- O Benesová
- Psychiatric Centre, Prague, Czech Republic
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30
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Vidal C. Nicotinic potentiation of glutamatergic synapses in the prefrontal cortex: New insight into the analysis of the role of nicotinic receptors in cognitive functions. Drug Dev Res 1994. [DOI: 10.1002/ddr.430310206] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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31
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Mackay KB, Dewar D, McCulloch J. kappa-1 Opioid receptors of the temporal cortex are preserved in Alzheimer's disease. JOURNAL OF NEURAL TRANSMISSION. PARKINSON'S DISEASE AND DEMENTIA SECTION 1994; 7:73-9. [PMID: 8579771 DOI: 10.1007/bf02252664] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The binding of [3H]-U-69593 and [3H]-CI-977 to kappa-1 opioid receptors has been examined in the temporal cortex of postmortem brains from patients with Alzheimer's disease and age-matched controls using quantitative autoradiography. There was no significant difference between Alzheimer and control subjects in the level of [3H]-U-69593 and [3H]-CI-977 binding, but ChAT activity was markedly reduced (by 73% compared to controls). These results are not consistent with a presynaptic localisation of kappa-1 receptors on cholinergic terminals in human temporal cortex.
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Affiliation(s)
- K B Mackay
- Wellcome Neuroscience Group, Wellcome Surgical Institute & Hugh Fraser Neuroscience Labs., University of Glasgow, Scotland, United Kingdom
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32
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Dewar D, McCulloch J. Abnormalities in Non-Cholinergic Neurotransmitter Systems in Alzheimer’s Disease. DEMENTIA 1994. [DOI: 10.1007/978-1-4615-6805-6_11] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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33
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Nagahara AH, Nicolle MM, Gallagher M. Alterations in [3H]-kainate receptor binding in the hippocampal formation of aged Long-Evans rats. Hippocampus 1993; 3:269-77. [PMID: 8394771 DOI: 10.1002/hipo.450030304] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
The present study used in vitro autoradiography to examine the density of [3H]-kainate (KA) binding in subregions of the hippocampal formation and certain cortical areas in young (7-8 months) and aged (27-29 months) Long-Evans rats. In addition, the topography of KA binding in the dentate molecular layer was examined for evidence of reactive reorganization in the aged brain. This investigation of age-related changes in [3H]-KA binding included correlations with the animals' spatial learning performance in a Morris water maze. The results showed an age-related decrease in the density of [3H]-KA binding in several regions of the hippocampal formation (CA3, CA1, hilus) and within related cortical areas (subicular complex, entorhinal cortex, perirhinal cortex). In addition, an expanded zone of KA binding in the molecular layer of the dentate gyrus was observed in the aged group. This expansion of KA binding may reflect sprouting due to a loss of perforant path input to the dentate. The results of additional correlational analyses, however, indicated that these changes in the density and topography of [3H]-KA binding were not strongly correlated with a decline in place learning ability.
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Affiliation(s)
- A H Nagahara
- Department of Psychology, University of North Carolina, Chapel Hill 27599-3270
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34
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Potier MC, Spillantini MG, Carter NP. The human glutamate receptor cDNA GluR1: cloning, sequencing, expression and localization to chromosome 5. DNA SEQUENCE : THE JOURNAL OF DNA SEQUENCING AND MAPPING 1992; 2:211-8. [PMID: 1320959 DOI: 10.3109/10425179209020805] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
The rat glutamate receptor is a 907 amino acid transmembrane protein. Using the rat GluR1 cDNA as a probe, we have isolated cDNA clones from a human hippocampal cDNA library. Sequence of a full length cDNA clone revealed 98.2% and 89.4% identity to the rat sequence at the amino acid and nucleotide levels respectively. The human cDNA clone detected an RNA transcript in human cerebral cortex, hippocampus and cerebellum, similar to that seen in rat. In situ hybridization experiments showed that human GluR1 mRNA is present in granule and pyramidal cells in the hippocampal formation and that there is no apparent difference of distribution between control patient and patient with Alzheimer's disease. Dot blot analysis of flow-sorted human chromosomes showed that the GluR1 gene maps to chromosome 5.
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Affiliation(s)
- M C Potier
- Medical Research Council, Laboratory of Molecular Biology, Cambridge, England
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35
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Storm-Mathisen J, Danbolt NC, Rothe F, Torp R, Zhang N, Aas JE, Kanner BI, Langmoen I, Ottersen OP. Chapter 19: Ultrastructural immunocytochemical observations on the localization, metabolism and transport of glutamate in normal and ischemic brain tissue. PROGRESS IN BRAIN RESEARCH 1992; 94:225-41. [PMID: 1363142 DOI: 10.1016/s0079-6123(08)61753-7] [Citation(s) in RCA: 67] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
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36
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Klunk WE, McClure RJ, Pettegrew JW. Possible roles of L-phosphoserine in the pathogenesis of Alzheimer's disease. MOLECULAR AND CHEMICAL NEUROPATHOLOGY 1991; 15:51-73. [PMID: 1837714 DOI: 10.1007/bf03161056] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
L-Phosphoserine is a membrane metabolite that is elevated in Alzheimer's disease brain. This compound has close structural similarity to L-glutamate. Electrophysiological studies indicate that L-phosphoserine has an acute inhibitory effect, but a delayed excitatory action. A hypothesis is developed based on pharmacological and electrophysiological studies that suggest that the inhibition may be mediated through presynaptic inhibition of L-glutamate release or perhaps antagonism of postsynaptic kainic acid receptors. The mechanism of the delayed excitation may lie in the tendency of L-phosphoserine to mimic the action of L-2-amino-4-phosphonobutyric acid, a blocker of chloride- and calcium-sensitive L-glutamate transport. L-Phosphoserine has also been found to be a competitive antagonist at the N-methyl-D-aspartate recognition site and an antagonist of metabotropic receptor-mediated hydrolysis of inositol phospholipids. Because of these actions, there are several potentially important implications for the elevation of L-phosphoserine in Alzheimer's disease, including production memory impairment through presynaptic inhibition of L-glutamate release or blockade of postsynaptic N-methyl-D-aspartate receptors and/or blockade of certain L-glutamate transport sites resulting in increased L-glutamate levels in the synaptic cleft.
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Affiliation(s)
- W E Klunk
- Department of Psychiatry, Western Psychiatric Institute and Clinic, University of Pittsburgh School of Medicine, PA
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37
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McLaughlin M, Ross BM, Milligan G, McCulloch J, Knowler JT. Robustness of G proteins in Alzheimer's disease: an immunoblot study. J Neurochem 1991; 57:9-14. [PMID: 1904911 DOI: 10.1111/j.1471-4159.1991.tb02092.x] [Citation(s) in RCA: 59] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Many of the neurotransmitter systems that are altered in senile dementia of the Alzheimer type are known to mediate their effects via G proteins, yet the integrity of guanine nucleotide-binding proteins (G proteins) in Alzheimer's diseased brains has received minimal investigation. The aim of this study was to establish whether the level of G alpha subunits of five G proteins was altered in Alzheimer's disease. We used immunoblotting (Western blotting) to compare the amounts of Gi1, Gi2, GsH (heavy molecular weight), GsL (light molecular weight), and Go in the frontal cortex and hippocampus, two regions severely affected by the disease, and the cerebellum, which is less severely affected. The number of senile plaques was also quantified. We report that there was no significant difference in the level of these G alpha subunits between Alzheimer's diseased and age-matched postmortem brains. These results suggest that alterations in the amount of G protein alpha subunits are not a feature of Alzheimer's disease.
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Affiliation(s)
- M McLaughlin
- Department of Biochemistry, Wellcome Surgical Institute, University of Glasgow, Scotland
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38
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Klunk WE, McClure RJ, Pettegrew JW. L-phosphoserine, a metabolite elevated in Alzheimer's disease, interacts with specific L-glutamate receptor subtypes. J Neurochem 1991; 56:1997-2003. [PMID: 1673996 DOI: 10.1111/j.1471-4159.1991.tb03458.x] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
L-Phosphoserine is one of the phosphomonoesters elevated in Alzheimer's disease brain and has close structural similarity to L-glutamate. This study attempts to define precisely the actions of L-phosphoserine at L-glutamate receptor subtypes. L-Phosphoserine is shown to bind to N-methyl-D-aspartate and kainic acid receptor subtypes, but not to the quisqualic acid subtype. Studies of [3H]MK-801 binding in the presence and absence of L-glutamate and glycine show L-phosphoserine to be a competitive N-methyl-D-aspartate antagonist. The IC50 of L-phosphoserine in these studies varies from 373 to 721 microM. This may indicate a physiologically relevant action of L-phosphoserine in Alzheimer's disease brain because whole brain concentrations may reach over 1 mM.
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Affiliation(s)
- W E Klunk
- Department of Psychiatry, University of Pittsburgh School of Medicine, Pennsylvania
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Horsburgh K, Dewar D, Graham DI, McCulloch J. Autoradiographic imaging of [3H]phorbol 12,13-dibutyrate binding to protein kinase C in Alzheimer's disease. J Neurochem 1991; 56:1121-9. [PMID: 2002333 DOI: 10.1111/j.1471-4159.1991.tb11401.x] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Quantitative autoradiography was used to examine the distribution of [3H]phorbol 12,13-dibutyrate ([3H]PDBu) binding to protein kinase C in the middle frontal and temporal cortices and the hippocampal region of nine control and nine elderly subjects with Alzheimer's disease (AD). AD patients had a clinical diagnosis of the disease that was confirmed neuropathologically by the presence of numerous plaques in the hippocampus and cerebral cortex. Choline acetyltransferase (ChAT) activity was significantly reduced in the middle frontal and temporal cortex and in the hippocampus of AD subjects, with the deficit being greater than 60% of control values. Quantitative autoradiographic analysis of [3H]PDBu binding to protein kinase C revealed a heterogeneous pattern in control brain, being particularly high in superficial layers of the cortex and CA1 of the hippocampus. There were no significant differences between control and AD sections in all areas examined within the middle frontal cortex; e.g., layers I-II control, 491 +/- 46 versus AD, 537 +/- 39 pmol/g of tissue; middle temporal cortex, e.g., layers I-II control, 565 +/- 68 versus AD, 465 +/- 72 pmol/g of tissue; and hippocampal formation, e.g., CA1 control, 511 +/- 28 versus AD, 498 +/- 25 pmol/g of tissue. In a parallel study, [3H]PDBu binding to homogenate preparations of control and AD brain confirmed that there was no significant difference in [3H]PDBu binding in either the particulate or the cytosolic fraction. We have demonstrated in a well-defined population of AD patients that [3H]PDBu binding to protein kinase C remains preserved in brain regions that are severely affected by the neuropathological and neurochemical correlates of AD.
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Affiliation(s)
- K Horsburgh
- Wellcome Surgical Institute, University of Glasgow, Scotland
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ORAL COMMUNICATIONS. Br J Pharmacol 1991. [DOI: 10.1111/j.1476-5381.1991.tb16274.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
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Dewar D, Chalmers DT, Shand A, Graham DI, McCulloch J. Selective reduction of quisqualate (AMPA) receptors in Alzheimer cerebellum. Ann Neurol 1990; 28:805-10. [PMID: 1980999 DOI: 10.1002/ana.410280612] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Multiple sites involved in glutamatergic neurotransmission were examined in the cerebellar cortex of 6 patients with Alzheimer's disease and 6 age-matched control patients by using quantitative ligand-binding autoradiography. Quisqualate (AMPA) receptor binding was markedly reduced in the molecular layer of the cerebellum from patients with Alzheimer's disease (167 +/- 13 pmoles/gm) compared with control patients (280 +/- 13 pmoles/gm). In adjacent sections from the same patients and controls, there was preservation of kainate and N-methyl-D-aspartate receptor binding in the cerebellum from patients with Alzheimer's disease compared with control patients. Neuropathological examination of the cerebellar cortex revealed the presence of plaques and preservation of Purkinje cells in the patients with Alzheimer's disease.
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Affiliation(s)
- D Dewar
- Wellcome Neuroscience Group, Wellcome Surgical Institute, Glasgow, UK
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