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Roy S, Lutsenko S. Mechanism of Cu entry into the brain: many unanswered questions. Neural Regen Res 2024; 19:2421-2429. [PMID: 38526278 PMCID: PMC11090436 DOI: 10.4103/1673-5374.393107] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2023] [Revised: 11/10/2023] [Accepted: 12/09/2023] [Indexed: 03/26/2024] Open
Abstract
Brain tissue requires high amounts of copper (Cu) for its key physiological processes, such as energy production, neurotransmitter synthesis, maturation of neuropeptides, myelination, synaptic plasticity, and radical scavenging. The requirements for Cu in the brain vary depending on specific brain regions, cell types, organism age, and nutritional status. Cu imbalances cause or contribute to several life-threatening neurologic disorders including Menkes disease, Wilson disease, Alzheimer's disease, Parkinson's disease, and others. Despite the well-established role of Cu homeostasis in brain development and function, the mechanisms that govern Cu delivery to the brain are not well defined. This review summarizes available information on Cu transfer through the brain barriers and discusses issues that require further research.
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Affiliation(s)
- Shubhrajit Roy
- Department of Physiology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Svetlana Lutsenko
- Department of Physiology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
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2
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Jin D, Wei X, He Y, Zhong L, Lu H, Lan J, Wei Y, Liu Z, Liu H. The nutritional roles of zinc for immune system and COVID-19 patients. Front Nutr 2024; 11:1385591. [PMID: 38706559 PMCID: PMC11066294 DOI: 10.3389/fnut.2024.1385591] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2024] [Accepted: 04/09/2024] [Indexed: 05/07/2024] Open
Abstract
Zinc (Zn) is a vital micronutrient that strengthens the immune system, aids cellular activities, and treats infectious diseases. A deficiency in Zn can lead to an imbalance in the immune system. This imbalance is particularly evident in severe deficiency cases, where there is a high susceptibility to various viral infections, including COVID-19 caused by SARS-CoV-2. This review article examines the nutritional roles of Zn in human health, the maintenance of Zn concentration, and Zn uptake. As Zn is an essential trace element that plays a critical role in the immune system and is necessary for immune cell function and cell signaling, the roles of Zn in the human immune system, immune cells, interleukins, and its role in SARS-CoV-2 infection are further discussed. In summary, this review paper encapsulates the nutritional role of Zn in the human immune system, with the hope of providing specific insights into Zn research.
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Affiliation(s)
- Di Jin
- Guangxi Key Laboratory of Metabolic Reprogramming and Intelligent Medical Engineering for Chronic Diseases, Department of Laboratory Medicine, Guangxi Clinical Research Center for Diabetes and Metabolic Diseases, The Second Affiliated Hospital of Guilin Medical University, Guilin, China
- College of Medical Laboratory Science, Guilin Medical University, Guilin, China
| | - Xinran Wei
- Guangxi Key Laboratory of Metabolic Reprogramming and Intelligent Medical Engineering for Chronic Diseases, Department of Laboratory Medicine, Guangxi Clinical Research Center for Diabetes and Metabolic Diseases, The Second Affiliated Hospital of Guilin Medical University, Guilin, China
- College of Medical Laboratory Science, Guilin Medical University, Guilin, China
| | - Yunyi He
- College of Medical Laboratory Science, Guilin Medical University, Guilin, China
| | - Luying Zhong
- College of Medical Laboratory Science, Guilin Medical University, Guilin, China
| | - Huijie Lu
- College of Medical Laboratory Science, Guilin Medical University, Guilin, China
| | - Jiaxin Lan
- College of Medical Laboratory Science, Guilin Medical University, Guilin, China
| | - Yuting Wei
- College of Medical Laboratory Science, Guilin Medical University, Guilin, China
| | - Zheng Liu
- College of Medical Laboratory Science, Guilin Medical University, Guilin, China
| | - Hongbo Liu
- Guangxi Key Laboratory of Metabolic Reprogramming and Intelligent Medical Engineering for Chronic Diseases, Department of Laboratory Medicine, Guangxi Clinical Research Center for Diabetes and Metabolic Diseases, The Second Affiliated Hospital of Guilin Medical University, Guilin, China
- College of Medical Laboratory Science, Guilin Medical University, Guilin, China
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3
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Yoo J, Han J, Lim MH. Transition metal ions and neurotransmitters: coordination chemistry and implications for neurodegeneration. RSC Chem Biol 2023; 4:548-563. [PMID: 37547459 PMCID: PMC10398360 DOI: 10.1039/d3cb00052d] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2023] [Accepted: 06/26/2023] [Indexed: 08/08/2023] Open
Abstract
Neurodegeneration is characterized by a disturbance in neurotransmitter-mediated signaling pathways. Recent studies have highlighted the significant role of transition metal ions, including Cu(i/ii), Zn(ii), and Fe(ii/iii), in neurotransmission, thereby making the coordination chemistry of neurotransmitters a growing field of interest in understanding signal dysfunction. This review outlines the physiological functions of transition metal ions and neurotransmitters, with the metal-binding properties of small molecule-based neurotransmitters and neuropeptides. Additionally, we discuss the structural and conformational changes of neurotransmitters induced by redox-active metal ions, such as Cu(i/ii) and Fe(ii/iii), and briefly describe the outcomes arising from their oxidation, polymerization, and aggregation. These observations have important implications for neurodegeneration and emphasize the need for further research to develop potential therapeutic strategies.
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Affiliation(s)
- Jeasang Yoo
- Department of Chemistry, Korea Advanced Institute of Science and Technology (KAIST) Daejeon 34141 Republic of Korea
| | - Jiyeon Han
- Department of Applied Chemistry, University of Seoul Seoul 02504 Republic of Korea
| | - Mi Hee Lim
- Department of Chemistry, Korea Advanced Institute of Science and Technology (KAIST) Daejeon 34141 Republic of Korea
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Hui Y, Guo G, Mao L, Li Y, Sun M, Wang X, Yang W, Fan X, Jiang K, Cui B, Sun C. Associations of Multiple Serum Trace Elements with Abnormal Sleep Duration Patterns in Hospitalized Patient with Cirrhosis. Biol Trace Elem Res 2022; 201:3202-3209. [PMID: 36136288 DOI: 10.1007/s12011-022-03425-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 09/14/2022] [Indexed: 11/02/2022]
Abstract
The associations of circulating trace elements with sleep health have attracted increasing attention given their potential link. However, there is scant data on the relationship between serum trace elements and abnormal sleep duration patterns in cirrhosis. We aimed to investigate these associations with the purpose of identifying modifiable risk factors. The blood samples were collected from inpatients with cirrhosis, and serum levels of several trace elements were assessed by inductively coupled plasma mass spectrometry. Self-reported sleep duration was categorized to short- (< 7 h/night), optimal (7-8 h/night), and long-sleep duration (> 8 h/night). The dose-response trends and associations of trace elements levels with sleep duration were determined by restricted cubic splines (RCS) and logistic regression, respectively. Cirrhotic patients with optimal sleep duration experienced the highest levels of serum Zinc (Zn) and the lowest values of copper to zinc ratio (CZr). RCS model corroborated non-linear associations of serum Zn and CZr against sleep duration. Multiple regression analysis showed that both CZr (short vs optimal sleep duration: OR 4.785, P < 0.001; long vs optimal sleep duration: OR 4.150, P = 0.019) and serum Zn levels (short vs optimal sleep duration: OR 0.985, P = 0.040; long vs optimal sleep duration: OR 0.956, P = 0.008) serve as independent risk factors for sleep duration abnormalities. In conclusion, our findings unraveled a close relationship of serum Zn and CZr with sleep duration in cirrhosis. Further trace element-based therapy such as Zn supplementation may be novel approach to reverse this sleep problem.
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Affiliation(s)
- Yangyang Hui
- Department of Gastroenterology and Hepatology, Tianjin Medical University General Hospital, Heping District, Anshan Road 154, Tianjin, 300052, China
- Tianjin Institute of Digestive Disease, Tianjin Medical University General Hospital, Heping District, Anshan Road 154, Tianjin, 300052, China
| | - Gaoyue Guo
- Department of Gastroenterology and Hepatology, Tianjin Medical University General Hospital, Heping District, Anshan Road 154, Tianjin, 300052, China
- Tianjin Institute of Digestive Disease, Tianjin Medical University General Hospital, Heping District, Anshan Road 154, Tianjin, 300052, China
| | - Lihong Mao
- Department of Gastroenterology and Hepatology, Tianjin Medical University General Hospital, Heping District, Anshan Road 154, Tianjin, 300052, China
- Tianjin Institute of Digestive Disease, Tianjin Medical University General Hospital, Heping District, Anshan Road 154, Tianjin, 300052, China
| | - Yifan Li
- Department of Gastroenterology and Hepatology, Tianjin Medical University General Hospital, Heping District, Anshan Road 154, Tianjin, 300052, China
- Tianjin Institute of Digestive Disease, Tianjin Medical University General Hospital, Heping District, Anshan Road 154, Tianjin, 300052, China
| | - Mingyu Sun
- Department of Gastroenterology and Hepatology, Tianjin Medical University General Hospital, Heping District, Anshan Road 154, Tianjin, 300052, China
- Tianjin Institute of Digestive Disease, Tianjin Medical University General Hospital, Heping District, Anshan Road 154, Tianjin, 300052, China
| | - Xiaoyu Wang
- Department of Gastroenterology and Hepatology, Tianjin Medical University General Hospital, Heping District, Anshan Road 154, Tianjin, 300052, China
- Tianjin Institute of Digestive Disease, Tianjin Medical University General Hospital, Heping District, Anshan Road 154, Tianjin, 300052, China
| | - Wanting Yang
- Department of Gastroenterology and Hepatology, Tianjin Medical University General Hospital, Heping District, Anshan Road 154, Tianjin, 300052, China
- Tianjin Institute of Digestive Disease, Tianjin Medical University General Hospital, Heping District, Anshan Road 154, Tianjin, 300052, China
| | - Xiaofei Fan
- Department of Gastroenterology and Hepatology, Tianjin Medical University General Hospital, Heping District, Anshan Road 154, Tianjin, 300052, China
- Tianjin Institute of Digestive Disease, Tianjin Medical University General Hospital, Heping District, Anshan Road 154, Tianjin, 300052, China
| | - Kui Jiang
- Department of Gastroenterology and Hepatology, Tianjin Medical University General Hospital, Heping District, Anshan Road 154, Tianjin, 300052, China
- Tianjin Institute of Digestive Disease, Tianjin Medical University General Hospital, Heping District, Anshan Road 154, Tianjin, 300052, China
| | - Binxin Cui
- Department of Gastroenterology, Tianjin Medical University General Hospital Airport Hospital, Tianjin Airport Economic Area, East Street 6, Tianjin, 300308, China
| | - Chao Sun
- Department of Gastroenterology and Hepatology, Tianjin Medical University General Hospital, Heping District, Anshan Road 154, Tianjin, 300052, China.
- Tianjin Institute of Digestive Disease, Tianjin Medical University General Hospital, Heping District, Anshan Road 154, Tianjin, 300052, China.
- Department of Gastroenterology, Tianjin Medical University General Hospital Airport Hospital, Tianjin Airport Economic Area, East Street 6, Tianjin, 300308, China.
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Expression Analysis of Zinc Transporters in Nervous Tissue Cells Reveals Neuronal and Synaptic Localization of ZIP4. Int J Mol Sci 2021; 22:ijms22094511. [PMID: 33925953 PMCID: PMC8123391 DOI: 10.3390/ijms22094511] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2021] [Revised: 04/19/2021] [Accepted: 04/23/2021] [Indexed: 12/14/2022] Open
Abstract
In the last years, research has shown that zinc ions play an essential role in the physiology of brain function. Zinc acts as a potent neuromodulatory agent and signaling ions, regulating healthy brain development and the function of both neurons and glial cells. Therefore, the concentration of zinc within the brain and its cells is tightly controlled. Zinc transporters are key regulators of (extra-) cellular zinc levels, and deregulation of zinc homeostasis and zinc transporters has been associated with neurodegenerative and neuropsychiatric disorders. However, to date, the presence of specific family members and their subcellular localization within brain cells have not been investigated in detail. Here, we analyzed the expression of all zinc transporters (ZnTs) and Irt-like proteins (ZIPs) in the rat brain. We further used primary rat neurons and rat astrocyte cell lines to differentiate between the expression found in neurons or astrocytes or both. We identified ZIP4 expressed in astrocytes but significantly more so in neurons, a finding that has not been reported previously. In neurons, ZIP4 is localized to synapses and found in a complex with major postsynaptic scaffold proteins of excitatory synapses. Synaptic ZIP4 reacts to short-term fluctuations in local zinc levels. We conclude that ZIP4 may have a so-far undescribed functional role at excitatory postsynapses.
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Sadri H, Larki NN, Kolahian S. Hypoglycemic and Hypolipidemic Effects of Leucine, Zinc, and Chromium, Alone and in Combination, in Rats with Type 2 Diabetes. Biol Trace Elem Res 2017; 180:246-254. [PMID: 28409409 DOI: 10.1007/s12011-017-1014-2] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/31/2017] [Accepted: 04/04/2017] [Indexed: 01/08/2023]
Abstract
For the increasing development of diabetes, dietary habits and using appropriate supplements can play important roles in the treatment or reduction of risk for this disease. The objective of this study was to investigate the effects of leucine (Leu), zinc (Zn), and chromium (Cr) supplementation, alone or in combination, in rats with type 2 diabetes (T2D). Seventy-seven adult male Wistar rats were randomly assigned in 11 groups, using nutritional supplements and insulin (INS) or glibenclamide (GLC). Supplementing Leu significantly reduced blood glucose, triglycerides (TG), nonesterified fatty acids (NEFA), low-density lipoprotein (LDL), and increased high-density lipoprotein (HDL) concentrations compared to vehicle-treated T2D animals, and those improvements were associated with reduced area under the 2-h blood glucose response curve (AUC). Supplementation of T2D animals with Zn improved serum lipid profile as well as blood glucose concentrations but was not comparable with the INS, GLC, and Leu groups. Supplementary Cr did not improve blood glucose and AUC in T2D rats, whereas it reduced serum TG and LDL and increased HDL concentrations. In conclusion, supplementation of diabetic rats with Leu was more effective in improving blood glucose and consequently decreasing glucose AUC than other nutritional supplements. Supplementary Zn and Cr only improved serum lipid profile. The combination of the nutritional supplements did not improve blood glucose level. Nevertheless, supplementation with Leu-Zn, Leu-Cr, Zn-Cr, and Leu-Zn-Cr led to an improved response in serum lipid profile over each supplement given alone.
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Affiliation(s)
- Hassan Sadri
- Department of Clinical Sciences, Faculty of Veterinary Medicine, University of Tabriz, Tabriz, 516616471, Iran.
| | - Negar Nowroozi Larki
- Department of Pharmacology and Experimental Therapy, Institute of Experimental and Clinical Pharmacology and Toxicology and ICePhA, University of Tuebingen, 72074, Tuebingen, Germany
- Department of Basic Sciences, Faculty of Veterinary Medicine, University of Tabriz, Tabriz, 516616471, Iran
| | - Saeed Kolahian
- Department of Pharmacology and Experimental Therapy, Institute of Experimental and Clinical Pharmacology and Toxicology and ICePhA, University of Tuebingen, 72074, Tuebingen, Germany
- Department of Basic Sciences, Faculty of Veterinary Medicine, University of Tabriz, Tabriz, 516616471, Iran
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Abstract
OBJECTIVE To review articles on the relationship of dietary and circulating micronutrients with sleep patterns, and to identify issues surrounding implications for future research and public health practice. DESIGN A systematic review was conducted. PubMed, Embase and Scopus were searched through January 2016. SETTING Both experimental and observational studies were included. However, studies that focused on secondary sleep impairment due to comorbidities were excluded. SUBJECTS Individuals in different age groups, from infants to older adults. RESULTS A total of twenty-six articles were selected. In the articles reviewed, researchers generally supported a potential role of micronutrients, particularly Fe and Mg, in the development of sleep stages among infants and in reversing age-related alterations in sleep architecture in older adults. Micronutrient status has also been linked to sleep duration, with sleep duration positively associated with Fe, Zn and Mg levels, and negatively associated with Cu, K and vitamin B12 levels. The mechanisms underlying these relationships include the impact of micronutrients on excitatory/inhibitory neurotransmitters and the expression of circadian genes. CONCLUSIONS Although the number of studies on the relationship between micronutrient status and sleep remains low, evidence has emerged that suggests a link between dietary/circulating micronutrients and sleep. Future research is needed to investigate the dose-dependent as well as the longitudinal relationships between micronutrient levels and human sleep across populations, test the interactions among micronutrients on sleep outcomes, and ultimately examine the clinical relevance of micronutrients on sleep health.
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Maureira C, Letelier JC, Alvarez O, Delgado R, Vergara C. Copper enhances cellular and network excitabilities, and improves temporal processing in the rat hippocampus. Eur J Neurosci 2015; 42:3066-80. [PMID: 26470005 DOI: 10.1111/ejn.13104] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2015] [Accepted: 10/03/2015] [Indexed: 11/27/2022]
Abstract
Copper, an ion with many important metabolic functions, has also been proposed to have a role as modulator on neuronal function, mostly based on its effects on voltage- and neurotransmitter-gated conductance as well as on neurological symptoms of patients with altered copper homeostasis. Nevertheless, the mechanisms by which copper exerts its neuromodulatory effects have not been clearly established in a functional neuronal network. Using rat hippocampus slices as a neuronal network model, the effects of copper in the range of 10-100 nm were tested on the intrinsic, synaptic and network properties of the CA1 region. Most of the previously described effects of this cation were in the micromolar range of copper concentrations. The current results indicate that copper is a multifaceted neuromodulator, having effects that may be grouped into two categories: (i) activity enhancement, by modulating synaptic communication and action potential (AP) conductances; and (ii) temporal processing and correlation extraction, by improving reliability and depressing inhibition. Specifically it was found that copper hyperpolarizes AP firing threshold, enhances neuronal and network excitability, modifies CA3-CA1 pathway gain, enhances the frequency of spontaneous synaptic events, decreases inhibitory network activity, and improves AP timing reliability. Moreover, copper chelation by bathocuproine decreases spontaneous network spiking activity. These results allow the proposal that copper affects the network activity from cellular to circuit levels on a moment-by-moment basis, and should be considered a crucial functional component of hippocampal neuronal circuitry.
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Affiliation(s)
- Carlos Maureira
- Departamento de Biología, Facultad de Ciencias, Universidad de Chile, Casilla 653, Santiago 7800003, Chile
| | - Juan Carlos Letelier
- Departamento de Biología, Facultad de Ciencias, Universidad de Chile, Casilla 653, Santiago 7800003, Chile
| | - Osvaldo Alvarez
- Departamento de Biología, Facultad de Ciencias, Universidad de Chile, Casilla 653, Santiago 7800003, Chile
| | - Ricardo Delgado
- Departamento de Biología, Facultad de Ciencias, Universidad de Chile, Casilla 653, Santiago 7800003, Chile
| | - Cecilia Vergara
- Departamento de Biología, Facultad de Ciencias, Universidad de Chile, Casilla 653, Santiago 7800003, Chile
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D'Ambrosi N, Rossi L. Copper at synapse: Release, binding and modulation of neurotransmission. Neurochem Int 2015; 90:36-45. [PMID: 26187063 DOI: 10.1016/j.neuint.2015.07.006] [Citation(s) in RCA: 113] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2015] [Revised: 06/30/2015] [Accepted: 07/10/2015] [Indexed: 10/23/2022]
Abstract
Over the last decade, a piece of the research studying copper role in biological systems was devoted to unravelling a still elusive, but extremely intriguing, aspect that is the involvement of copper in synaptic function. These studies were prompted to provide a rationale to the finding that copper is released in the synaptic cleft upon depolarization. The copper pump ATP7A, which mutations are responsible for diseases with a prominent neurodegenerative component, seems to play a pivotal role in the release of copper at synapses. Furthermore, it was found that, when in the synaptic cleft, copper can control, directly or indirectly, the activity of the neurotransmitter receptors (NMDA, AMPA, GABA, P2X receptors), thus affecting excitability. In turn, neurotransmission can affect copper trafficking and delivery in neuronal cells. Furthermore, it was reported that copper can also modulate synaptic vesicles trafficking and the interaction between proteins of the secretory pathways. Interestingly, proteins with a still unclear role in neuronal system though associated with the pathogenesis of neurodegenerative diseases (the amyloid precursor protein, APP, the prion protein, PrP, α-synuclein, α-syn) show copper-binding domains. They may act as copper buffer at synapses and participate in the interplay between copper and the neurotransmitters receptors. Given that copper dysmetabolism occurs in several diseases affecting central and peripheral nervous system, the findings on the contribution of copper in synaptic transmission, beside its more consolidate role as a neuronal enzymes cofactor, may open new insights for therapy interventions.
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Affiliation(s)
- Nadia D'Ambrosi
- Institute of Anatomy and Cell Biology, Università Cattolica del Sacro Cuore, Rome, Italy
| | - Luisa Rossi
- Department of Biology, University of Rome Tor Vergata, Rome, Italy.
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10
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Marchetti C. Interaction of metal ions with neurotransmitter receptors and potential role in neurodiseases. Biometals 2014; 27:1097-113. [PMID: 25224737 DOI: 10.1007/s10534-014-9791-y] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2014] [Accepted: 09/05/2014] [Indexed: 12/25/2022]
Abstract
There is increasing evidence that toxic metals play a role in diseases of unknown etiology. Their action is often mediated by membrane proteins, and in particular neurotransmitter receptors. This brief review will describe recent findings on the direct interaction of metal ions with ionotropic γ-aminobutyric acid (GABAA) and glutamate receptors, the main inhibitory and excitatory neurotransmitter receptors in the mammalian central nervous system, respectively. Both hyper and hypo function of these receptors are involved in neurological and psychotic syndromes and modulation by metal ions is an important pharmacological issue. The focus will be on three xenobiotic metals, lead (Pb), cadmium (Cd) and nickel (Ni) that have no biological function and whose presence in living organisms is only detrimental, and two trace metals, zinc (Zn) and copper (Cu), which are essential for several enzymatic functions, but can mediate toxic actions if deregulated. Despite limited access to the brain and tight control by metalloproteins, exogenous metals interfere with receptor performances by mimicking physiological ions and occupying one or more modulatory sites on the protein. These interactions will be discussed as a potential cause of neuronal dysfunction.
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Affiliation(s)
- Carla Marchetti
- Istituto di Biofisica, Consiglio Nazionale delle Ricerche, via De Marini, 6, 16149, Genoa, Italy,
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11
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Scheiber IF, Mercer JF, Dringen R. Metabolism and functions of copper in brain. Prog Neurobiol 2014; 116:33-57. [DOI: 10.1016/j.pneurobio.2014.01.002] [Citation(s) in RCA: 213] [Impact Index Per Article: 21.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2013] [Revised: 01/08/2014] [Accepted: 01/08/2014] [Indexed: 12/15/2022]
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12
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Gaier ED, Eipper BA, Mains RE. Copper signaling in the mammalian nervous system: synaptic effects. J Neurosci Res 2012; 91:2-19. [PMID: 23115049 DOI: 10.1002/jnr.23143] [Citation(s) in RCA: 74] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2012] [Revised: 08/05/2012] [Accepted: 08/17/2012] [Indexed: 12/14/2022]
Abstract
Copper is an essential metal present at high levels in the CNS. Its role as a cofactor in mitochondrial ATP production and in essential cuproenzymes is well defined. Menkes and Wilson's diseases are severe neurodegenerative conditions that demonstrate the importance of Cu transport into the secretory pathway. In the brain, intracellular levels of Cu, which is almost entirely protein bound, exceed extracellular levels by more than 100-fold. Cu stored in the secretory pathway is released in a Ca(2+)-dependent manner and can transiently reach concentrations over 100 μM at synapses. The ability of low micromolar levels of Cu to bind to and modulate the function of γ-aminobutyric acid type A (GABA(A)) receptors, N-methyl-D-aspartate (NMDA) receptors, and voltage-gated Ca(2+) channels contributes to its effects on synaptic transmission. Cu also binds to amyloid precursor protein and prion protein; both proteins are found at synapses and brain Cu homeostasis is disrupted in mice lacking either protein. Especially intriguing is the ability of Cu to affect AMP-activated protein kinase (AMPK), a monitor of cellular energy status. Despite this, few investigators have examined the direct effects of Cu on synaptic transmission and plasticity. Although the variability of results demonstrates complex influences of Cu that are highly method sensitive, these studies nevertheless strongly support important roles for endogenous Cu and new roles for Cu-binding proteins in synaptic function/plasticity and behavior. Further study of the many roles of Cu in nervous system function will reveal targets for intervention in other diseases in which Cu homeostasis is disrupted.
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Affiliation(s)
- E D Gaier
- Department of Neuroscience, University of Connecticut Health Center, Farmington, Connecticut 06030-3401, USA
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13
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Effects of aluminum trichloride on the trace elements and cytokines in the spleen of rats. Food Chem Toxicol 2012; 50:2911-5. [DOI: 10.1016/j.fct.2012.05.041] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2012] [Revised: 05/21/2012] [Accepted: 05/22/2012] [Indexed: 02/04/2023]
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14
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Salazar-Weber NL, Smith JP. Copper Inhibits NMDA Receptor-Independent LTP and Modulates the Paired-Pulse Ratio after LTP in Mouse Hippocampal Slices. Int J Alzheimers Dis 2011; 2011:864753. [PMID: 22028985 PMCID: PMC3199118 DOI: 10.4061/2011/864753] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2011] [Revised: 08/05/2011] [Accepted: 08/16/2011] [Indexed: 11/20/2022] Open
Abstract
Copper misregulation has been implicated in the pathological processes underlying deterioration of learning and memory in Alzheimer's disease and other neurodegenerative disorders. Supporting this, inhibition of long-term potentiation (LTP) by copper (II) has been well established, but the exact mechanism is poorly characterized. It is thought that an interaction between copper and postsynaptic NMDA receptors is a major part of the mechanism; however, in this study, we found that copper (II) inhibited NMDA receptor-independent LTP in the CA3 region of hippocampal slices. In addition, in the CA3 and CA1 regions, copper modulated the paired-pulse ratio (PPR) in an LTP-dependent manner. Combined, this suggests the involvement of a presynaptic mechanism in the modulation of synaptic plasticity by copper. Inhibition of the copper-dependent changes in the PPR with cyclothiazide suggested that this may involve an interaction with the presynaptic AMPA receptors that regulate neurotransmitter release.
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Affiliation(s)
- Nina L Salazar-Weber
- Department of Biology, Colorado State University-Pueblo, 2200 Bonforte Boulevard, Pueblo, CO 81001, USA
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15
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Characterization of GABA(A) receptors expressed in glial cell membranes of adult mouse neocortex using a Xenopus oocyte microtransplantation expression system. J Neurosci Methods 2011; 198:77-83. [PMID: 21439322 DOI: 10.1016/j.jneumeth.2011.03.011] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2010] [Revised: 03/09/2011] [Accepted: 03/10/2011] [Indexed: 11/21/2022]
Abstract
Cell membranes isolated from nervous tissue can be easily injected into Xenopus oocytes, thereby effectively "microtransplanting" functional neurotransmitter receptors. This technique therefore allows a direct functional characterization of the original membrane receptor/ion channel proteins and the associated molecules while still embedded in their natural lipid environment. Cell membranes will contain components from different types of cells, i.e. neurons and glial cells, expressing their own receptors, with possibly different properties. To study the receptor properties of a single cell type, we injected oocytes with membranes isolated only from glia (gliosomes) of adult mouse neocortex and we focused our work on GABA(A) receptors incorporated in the oocyte cell membrane. We found that GABA(A)-activated currents allowed a good biophysical and pharmacological characterization of glial GABA(A) receptors. Therefore, the microtransplantation of gliosomes into oocytes can represent a good model to study the electrical and pharmacological properties of adult glial cells under different physiological and pathological conditions. Moreover, since gliosomes can be isolated from frozen tissues, this approach can be extended to post-mortem human tissues.
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Nachev C, Ivancheva C, Apostolova MD, Radomirov R. Cholinergic responses of ileal longitudinal muscle under short-lasting exposure to cupric ions. ACTA ACUST UNITED AC 2008; 28:11-7. [PMID: 18257747 DOI: 10.1111/j.1474-8673.2007.00415.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
1 The effect of short-term exposure to cupric ions (Cu2+) on electric field-stimulated (EFS) or agonist-induced contractions of guinea-pig isolated ileum was studied. 2 EFS elicited tetrodotoxin- and atropine-sensitive contractions that were concentration dependently inhibited by Cu2+ (IC50 = 14.7 +/- 4.2 microm). Maximal inhibition (90.4 +/- 3.1% of baseline contractions) was attained with 30 microm Cu2+. 3 Carbachol induced concentration-dependent contractions (EC50 = 0.021 +/- 0.004 microm) that were inhibited by 0.3 microm atropine to a non-competitive manner (decreased maximal response, EC50 value = 0.26 +/- 0.04 microm, K(e) = 0.026 microm). Cu2+ (15 microm) potentiated contractions induced by carbachol, such that the maximum response was increased by 30.3 +/- 10.4%. 4 Histamine induced concentration-dependent contractions of the longitudinal muscle (EC50 = 0.11 +/- 0.03 microm). Dyphenhydramine (0.1 microm) decreased the maximum response to histamine and shifted the curve to the right (EC50 value = 4.71 +/- 0.35 microm, K(e) = 0.0024 microm). Cu2+ (15 microm) caused a rightward shift of the histamine concentration-response curve (EC50 = 0.61 +/- 0.1 microm) without changing the maximum response. Serotonin induced concentration-dependent contractions at concentrations higher than 10 nM (EC50 value of 0.34 +/- 0.12 microm) were not significantly affected by 15 microm Cu2+. 5 Our results suggest that in ileal longitudinal muscle, Cu2+ inhibits cholinergic neurotransmission but also facilitates postsynaptic muscarinic receptor responses.
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Affiliation(s)
- Ch Nachev
- Clinic of Cardiology, St Anne University Hospital, 1709 Sofia, Bulgaria
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Staruschenko A, Dorofeeva NA, Bolshakov KV, Stockand JD. Subunit-dependent cadmium and nickel inhibition of acid-sensing ion channels. Dev Neurobiol 2007; 67:97-107. [PMID: 17443775 DOI: 10.1002/dneu.20338] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Acid-sensing ion channels (ASIC) are ligand-gated cation channels that are highly expressed in peripheral sensory and central neurons. ASIC are transiently activated by decreases in extracellular pH and are thought to play important roles in sensory perception, neuronal transmission, and excitability, and in the pathology of neurological conditions, such as brain ischemia. We demonstrate here that the heavy metals Ni(2+) and Cd(2+) dose-dependently inhibit ASIC currents in hippocampus CA1 neurons and in Chinese hamster ovary (CHO) cells heterologously expressing these channels. The effects of both Ni(2+) and Cd(2+) were voltage-independent, fast, and reversible. Neither metal affected activation and desensitization kinetics but rather decreased pH-sensitivity. Moreover, distinct ASIC isoforms were differentially inhibited by Ni(2+) and Cd(2+). External application of 1 mM Ni(2+) rapidly inhibited homomeric ASIC1a and heteromeric ASIC1a/2a channels without affecting ASIC1b, 2a, and ASIC3 homomeric channels and ASIC1a/3 and 2a/3 heteromeric channels. In contrast, external Cd(+) (1 mM) inhibited ASIC2a and ASIC3 homomeric channels and ASIC1a/2a, 1a/3, and 2a/3 heteromeric channels but not ASIC1a homomeric channels. The acid-sensing current in isolated rat hippocampus CA1 neurons, thought to be carried primarily by ASIC1a and 1a/2a, was inhibited by 1 mM Ni(2+). The current study identifies ASIC as a novel target for the neurotoxic heavy metals Cd(2+) and Ni(2+).
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Affiliation(s)
- Alexander Staruschenko
- Department of Physiology, University of Texas Health Science Center at San Antonio, USA.
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Staruschenko A, Dorofeeva NA, Bolshakov KV, Stockand JD. Subunit-dependent cadmium and nickel inhibition of acid-sensing ion channels. ACTA ACUST UNITED AC 2007. [DOI: 10.1002/neu.20338] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Mathie A, Sutton GL, Clarke CE, Veale EL. Zinc and copper: pharmacological probes and endogenous modulators of neuronal excitability. Pharmacol Ther 2006; 111:567-83. [PMID: 16410023 DOI: 10.1016/j.pharmthera.2005.11.004] [Citation(s) in RCA: 184] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2005] [Accepted: 11/23/2005] [Indexed: 12/19/2022]
Abstract
As well as being key structural components of many proteins, increasing evidence suggests that zinc and copper ions function as signaling molecules in the nervous system and are released from the synaptic terminals of certain neurons. In this review, we consider the actions of these two ions on proteins that regulate neuronal excitability. In addition to the established actions of zinc, and to a lesser degree copper, on excitatory and inhibitory ligand-gated ion channels, we show that both ions have a number of actions on selected members of the voltage-gated-like ion channel superfamily. For example, zinc is a much more effective blocker of one subtype of tetrodotoxin (TTX)-insensitive sodium (Na+) channel (NaV1.5) than other Na+ channels, whereas a certain T-type calcium (Ca2+) channel subunit (CaV3.2) is particularly sensitive to zinc. For potassium (K+) channels, zinc can have profound effects on the gating of certain KV channels whereas zinc and copper have distinct actions on closely related members of the 2 pore domain potassium channel (K2P) channel family. In addition to direct actions on these proteins, zinc is able to permeate a number of membrane proteins such as (S)-alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid (AMPA)/kainate receptors, Ca2+ channels and some transient receptor potential (trp) channels. There are a number of important physiological and pathophysiological consequences of these many actions of zinc and copper on membrane proteins, in terms of regulation of neuronal excitability and neurotoxicity. Furthermore, the concentration of free zinc and copper either in the synaptic cleft or neuronal cytoplasm may contribute to the etiology of certain disease states such as Alzheimer's disease (AD) and epilepsy.
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Affiliation(s)
- Alistair Mathie
- Biophysics Section, Blackett Laboratory, Division of Cell and Molecular Biology, Imperial College London, Exhibition Road, London SW7 2AZ, United Kingdom
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20
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Abstract
There is considerable evidence that the transition metal zinc plays an important role in mammalian neural development, physiology and pathology. The most compelling evidence for a synaptic role for zinc comes from hippocampal studies: zinc is concentrated in the synaptic vesicles of some glutamatergic neurons, zinc can be released during neural activity and zinc can modulate postsynaptic GABA and glutamate receptors. The possibility that zinc is involved in cerebellar synaptic transmission is supported by the expression of specific zinc transporters (ZnT, including the synaptic vesicle transporter ZnT-3) in the cerebellar cortex. Furthermore, some subtypes of neurotransmitter receptors, expressed by cerebellar neurones, are highly sensitive to low concentrations of exogenous zinc. However there appears to be little chelatable (synaptic) zinc in the cerebellum, deletion of the ZnT-3 gene has no effect on motor phenotype and there is currently no evidence that zinc is released from cerebellar neurones to have physiological actions. Thus it is possible that the different types of zinc transporter found in the cerebellum play a neuroprotective rather than a signalling role.
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Affiliation(s)
- Mark J Wall
- Neuroscience Group, Department of Biological Sciences, University of Warwick, Coventry, UK.
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21
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Kozhemiakin MB, Draguhn A, Skrebitsky VG. Layer-specific potentiation of evoked IPSCs in rat hippocampal CA1 pyramidal cells by lanthanum. Brain Res Bull 2004; 64:97-101. [PMID: 15342096 DOI: 10.1016/j.brainresbull.2004.06.004] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2003] [Revised: 06/03/2004] [Accepted: 06/08/2004] [Indexed: 11/22/2022]
Abstract
Lanthanum (La3+) potentiates or depresses GABAA receptors (GABAAR) in a subunit-dependent manner. Such differential modulators may help to discriminate between-layer-specific inhibitory synaptic inputs to individual neurons, which use different molecular GABAAR isoforms. Here, we show that inhibitory postsynaptic currents (IPSCs) in CA1 pyramidal cells are potentiated by La3+ (100 microM) when they are evoked by stimulation in stratum oriens. In contrast, stimulation in stratum radiatum yields IPSCs which are not sensitive towards La3+. These data point towards an input-specific molecular and functional diversity of inhibitory synapses at CA1 pyramidal cells.
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Kim H, Macdonald RL. An N-Terminal Histidine Is the Primary Determinant of α Subunit-Dependent Cu2+Sensitivity of αβ3γ2L GABAAReceptors. Mol Pharmacol 2003; 64:1145-52. [PMID: 14573764 DOI: 10.1124/mol.64.5.1145] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Copper (Cu2+) is a physiologically important cation and is released from nerve terminals. Cu2+ modulates GABAA receptor currents in an alpha subunit subtype-dependent manner; alpha1beta3gamma2L receptors are more sensitive to Cu2+ than alpha6beta3gamma2L receptors. We compared the effect of Cu2+ on alphabeta3gamma2L receptors containing each of the six alpha subtypes and generated alpha1/alpha6 chimeras and mutants to determine the functional domain(s) and specific residues responsible for alpha subtype-dependent differences in Cu2+ sensitivity. Whole-cell GABAA receptor currents were obtained from L929 fibroblasts coexpressing wild-type, chimeric and mutant alpha subunits with beta3 and gamma2L subunits. Maximal Cu2+ inhibition of alpha1beta3gamma2L and alpha2beta3gamma2L receptor currents was larger (52.2 +/- 3.0 and 59.0 +/- 2.5%, respectively) than maximal inhibition of alpha3beta3gamma2L, alpha4beta3gamma2L, alpha5beta3gamma2L, and alpha6beta3gamma2L receptor currents (22.6 +/- 3.1, 19.2 +/- 3.4, 20.2 +/- 4.8, and 21.2 +/- 3.6%, respectively). Receptors containing chimeric constructs with alpha1 subtype N-terminal sequence between residues 127 and 232 were inhibited by Cu2+ to an extent similar to those with alpha1 subtypes, suggesting that this N-terminal region (127-232) contains a major determinant for high Cu2+ sensitivity. alpha1 subtype residues V134, R135, and H141 in a VRAECPMH motif (VQAECPMH in the alpha2 subtype) conferred higher Cu2+ sensitivity, and the H141 residue was the major determinant in the motif. The beta3 subtype M2 domain residue H267, which is a major determinant of Zn2+ inhibition, and alpha6 subtype M2-M3 loop residue H273, which is responsible for the increased Zn2+ sensitivity of the alpha6 subtype, also seemed to contribute to Cu2+ inhibition. These data suggest that the N-terminal VR(Q)AECPMH motif in alpha1 and alpha2 subtypes is the major determinant of increased subtype-dependent inhibition by Cu2+, that residue H141 is the major determinant in that motif, and that Cu2+ may also interact with GABAA receptors at sites similar to or overlapping Zn2+ sites.
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Affiliation(s)
- Heejeong Kim
- Department of Neurology, University of Michigan, Ann Arbor, MI, USA
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Vorobjev VS, Sharonova IN, Sergeeva OA, Haas HL. Modulation of ATP-induced currents by zinc in acutely isolated hypothalamic neurons of the rat. Br J Pharmacol 2003; 139:919-26. [PMID: 12839865 PMCID: PMC1573915 DOI: 10.1038/sj.bjp.0705321] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
1. Whole-cell patch-clamp and fast perfusion were used to study the effects of zinc on adenosine 5'-triphosphate (ATP)-induced responses of histaminergic neurons. 2. At 10-30 micro M ATP, Zn(2+) had biphasic effects on ATP responses. Zn(2+) at 3-100 micro M increased the ATP-induced currents, but inhibited them at higher concentrations. 3. At 300 micro M ATP, Zn(2+) predominantly but incompletely inhibited the currents. 4. At 5 and 50 micro M, Zn(2+) shifted to the left the concentration-response curve for ATP-induced currents, without changing the maximal response. At 1 mM, Zn(2+) inhibited ATP-induced currents in a noncompetitive way, reducing the maximal response by 58%. .Zn(2+) increased the decay time of ATP-evoked currents nine fold with an EC(50) of 63 micro M. Upon removal of high concentrations of Zn(2+), there was a rapid increase of the current followed by a slow decline towards the response amplitude seen with ATP alone. The appearance of a tail current is consistent with a Zn(2+)-induced increase of ATP affinity and an inhibition of its efficacy. 6. Thus, Zn(2+) acts as a bidirectional modulator of ATP receptor channels in tuberomamillary neurons, which possess functional P2X(2) receptors. The data are consistent with the existence of two distinct modulatory sites on the P2X receptor, which can be occupied by Zn(2+). 7. Our data suggest that zinc-induced potentiation of ATP-mediated currents is caused by the slowing of ATP dissociation from the receptor, while inhibition of ATP-induced currents is related to the suppression of ATP receptor gating.
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Affiliation(s)
- Vladimir S Vorobjev
- Department of Neurophysiology, Heinrich-Heine-University, Duesseldorf, Germany
| | - Irina N Sharonova
- Department of Neurophysiology, Heinrich-Heine-University, Duesseldorf, Germany
| | - Olga A Sergeeva
- Department of Neurophysiology, Heinrich-Heine-University, Duesseldorf, Germany
- Author for correspondence:
| | - Helmut L Haas
- Department of Neurophysiology, Heinrich-Heine-University, Duesseldorf, Germany
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Wang DS, Zhu HL, Hong Z, Li JS. Cu(2+) inhibition of glycine-activated currents in rat sacral dorsal commissural neurons. Neurosci Lett 2002; 328:117-20. [PMID: 12133569 DOI: 10.1016/s0304-3940(02)00498-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The effect of Cu(2+) on glycine (Gly) response was examined in neurons acutely dissociated from the rat sacral dorsal commissural nucleus (SDCN) using the nystatin perforated patch clamp recording configuration under voltage-clamp conditions. Cu(2+), in the concentration range 10-1000 microM, reversibly inhibited chloride current activated by 30 microM Gly at a holding potential of -40 mV with an IC(50) of 88.4 microM. Cu(2+) shifted the Gly concentration response curve to the right in a parallel manner, which indicated that Cu(2+) decreased the apparent affinity of the receptor for Gly. Cu(2+) suppression of Gly-activated current was independent of membrane potential between -60 and +60 mV and did not involve a shift in the reversal potential of the current. Furthermore, Cu(2+) antagonized the inhibitory action of Zn(2+) in a concentration-dependent manner, suggesting a common site or mechanism of action of Cu(2+) and Zn(2+) on Gly receptors. The results show that Cu(2+) is a potent inhibitor of Gly receptor-mediated responses in rat spinal neurons.
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Affiliation(s)
- Dian-Shi Wang
- Department of Anatomy and K. K. Leung Brain Research Centre, Fourth Military Medical University, Xi'an 710032, China.
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Kolbaev SN, Sharonova IN, Vorobjev VS, Skrebitsky VG. Mechanisms of GABA(A) receptor blockade by millimolar concentrations of furosemide in isolated rat Purkinje cells. Neuropharmacology 2002; 42:913-21. [PMID: 12069901 DOI: 10.1016/s0028-3908(02)00042-4] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The action of diuretic furosemide on the GABA(A) receptor was studied in acutely isolated Purkinje cells using the whole-cell recording and fast application system. Furosemide blocked stationary component of GABA-activated currents in a concentration-dependent manner with IC(50) value > 5 mM at -70 mV. The inhibition was rapid in the onset, fully reversible and did not require drug pre-perfusion. The termination of GABA and furosemide co-application was followed by transient increase in the inward current 'tail' current, which was not observed when furosemide was continuously present in the solution. The degree of furosemide block did not depend on GABA concentration. Furosemide block increased with membrane depolarization. Five millimolar furosemide depressed GABA currents by 32.4+/-1.3% at -70 mV and by 76.7+/-5.0% at +70 mV. Analysis of the voltage dependence of the block suggests that furosemide binds at the site located within GABA(A) channel pore with a dissociation constant of 5.3+/-0.5 mM at 0 mV and electric distance of 0.27. Our results provide evidence that furosemide interacts with Purkinje cell GABA(A) receptors (most probably composed of alpha1beta2/3gamma2 subunits) through a low affinity site located in channel pore and suggest that furosemide acts as a sequential open channel blocker, which prevents the dissociation of agonist while the channel is blocked.
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Affiliation(s)
- Sergey N Kolbaev
- Brain Research Institute, Russian Academy of Medical Sciences, Moscow, Russia.
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