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Fernandes E, Ledo A, Gerhardt GA, Barbosa RM. Amperometric bio-sensing of lactate and oxygen concurrently with local field potentials during status epilepticus. Talanta 2024; 268:125302. [PMID: 37826935 PMCID: PMC11164042 DOI: 10.1016/j.talanta.2023.125302] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2023] [Revised: 10/03/2023] [Accepted: 10/07/2023] [Indexed: 10/14/2023]
Abstract
Epilepsy is a prevalent neurological disorder with a complex pathogenesis and unpredictable nature, presenting limited treatment options in >30 % of affected individuals. Neurometabolic abnormalities have been observed in epilepsy patients, suggesting a disruption in the coupling between neural activity and energy metabolism in the brain. In this study, we employed amperometric biosensors based on a modified carbon fiber microelectrode platform to directly and continuously measure lactate and oxygen dynamics in the brain extracellular space. These biosensors demonstrated high sensitivity, selectivity, and rapid response time, enabling in vivo measurements with high temporal and spatial resolution. In vivo recordings in the cortex of anaesthetized rats revealed rapid and multiphasic fluctuations in extracellular lactate and oxygen levels following neuronal stimulation with high potassium. Furthermore, real-time measurement of lactate and oxygen concentration dynamics concurrently with network electrical activity during status epilepticus induced by 4-aminopyridine (4-AP) demonstrated phasic changes in lactate levels that correlated with bursts of electrical activity, while tonic levels of lactate remained stable during seizures. This study highlights the complex interplay between lactate dynamics, electrical activity, and oxygen utilization in epileptic seizures.
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Affiliation(s)
- Eliana Fernandes
- University of Coimbra, Faculty of Pharmacy, Health Sciences Campus, Azinhaga de Santa Comba, 3000-548, Coimbra, Portugal; Center for Neuroscience and Cell Biology, University of Coimbra, 3004-504, Coimbra, Portugal
| | - Ana Ledo
- University of Coimbra, Faculty of Pharmacy, Health Sciences Campus, Azinhaga de Santa Comba, 3000-548, Coimbra, Portugal; Center for Neuroscience and Cell Biology, University of Coimbra, 3004-504, Coimbra, Portugal
| | - Greg A Gerhardt
- Center for Microelectrode Technology (CenMeT), Department of Neuroscience, University of Kentucky Medical Center, Lexington, KY, 40536, United States
| | - Rui M Barbosa
- University of Coimbra, Faculty of Pharmacy, Health Sciences Campus, Azinhaga de Santa Comba, 3000-548, Coimbra, Portugal; Center for Neuroscience and Cell Biology, University of Coimbra, 3004-504, Coimbra, Portugal.
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2
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Wang S, Liu Y, Zhu A, Tian Y. In Vivo Electrochemical Biosensors: Recent Advances in Molecular Design, Electrode Materials, and Electrochemical Devices. Anal Chem 2023; 95:388-406. [PMID: 36625112 DOI: 10.1021/acs.analchem.2c04541] [Citation(s) in RCA: 25] [Impact Index Per Article: 25.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Electrochemical biosensors provide powerful tools for dissecting the dynamically changing neurochemical signals in the living brain, which contribute to the insight into the physiological and pathological processes of the brain, due to their high spatial and temporal resolutions. Recent advances in the integration of in vivo electrochemical sensors with cross-disciplinary advances have reinvigorated the development of in vivo sensors with even better performance. In this Review, we summarize the recent advances in molecular design, electrode materials, and electrochemical devices for in vivo electrochemical sensors from molecular to macroscopic dimensions, highlighting the methods to obtain high performance for fulfilling the requirements for determination in the complex brain through flexible and smart design of molecules, materials, and devices. Also, we look forward to the development of next-generation in vivo electrochemical biosensors.
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Affiliation(s)
- Shidi Wang
- Shanghai Key Laboratory of Green Chemistry and Chemical Processes, Department of Chemistry, School of Chemistry and Molecular Engineering, East China Normal University, Dongchuan Road 500, Shanghai 200241, China
| | - Yuandong Liu
- Shanghai Key Laboratory of Green Chemistry and Chemical Processes, Department of Chemistry, School of Chemistry and Molecular Engineering, East China Normal University, Dongchuan Road 500, Shanghai 200241, China
| | - Anwei Zhu
- Shanghai Key Laboratory of Green Chemistry and Chemical Processes, Department of Chemistry, School of Chemistry and Molecular Engineering, East China Normal University, Dongchuan Road 500, Shanghai 200241, China
| | - Yang Tian
- Shanghai Key Laboratory of Green Chemistry and Chemical Processes, Department of Chemistry, School of Chemistry and Molecular Engineering, East China Normal University, Dongchuan Road 500, Shanghai 200241, China
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3
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Chen X, Li L, Sui L. Alterations in amperometric cholinergic signals accompanied by synaptic plasticity and γ oscillations in the hippocampus-medial prefrontal cortex pathway. Neuroreport 2021; 32:1428-1435. [PMID: 34776505 DOI: 10.1097/wnr.0000000000001746] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
OBJECTIVE Neural projections from the ventral hippocampal CA1 (vCA1) to the medial prefrontal cortex (mPFC) and from the posterior dorsal hippocampal CA1 (pdCA1) to the mPFC are important for information processing. Previous studies have revealed that two forms of long-term synaptic plasticity, long-term potentiation (LTP) and long-term depression (LTD), and γ oscillations, which are all believed to be neural bases for learning and memory in the vCA1-mPFC and the pdCA1-mPFC pathways, exhibited distinct profiles. However, the underlying mechanism is unclear. METHODS In the present study, amperometric cholinergic signals were monitored during in-vivo electrophysiological recordings of evoked extracellular postsynaptic potentials and spontaneous local field potentials. RESULTS The results demonstrated that in the vCA1-mPFC pathway, increased cholinergic currents and γ power of the amperometric cholinergic signals were accompanied by the induction of LTD and increased γ power of local field potentials, whereas, in the pdCA1-mPFC pathway, decreased cholinergic currents and increased γ power of the amperometric cholinergic signals were accompanied by the induction of LTP and increased γ power of local field potentials. CONCLUSION These findings indicated that some correlations may exist between amperometric cholinergic signals and synaptic plasticity in the hippocampus-mPFC pathway. The pattern of alterations in cholinergic signals may help to illustrate the specific properties of synaptic plasticity and γ oscillations in the vCA1-mPFC and the pdCA1-mPFC pathways.
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Affiliation(s)
- XiaoYu Chen
- School of Medical Instrument and Food Engineering, University of Shanghai for Science and Technology, Shanghai, China
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4
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Santos RM, Sirota A. Phasic oxygen dynamics confounds fast choline-sensitive biosensor signals in the brain of behaving rodents. eLife 2021; 10:61940. [PMID: 33587035 PMCID: PMC7932690 DOI: 10.7554/elife.61940] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2020] [Accepted: 02/12/2021] [Indexed: 02/06/2023] Open
Abstract
Cholinergic fast time-scale modulation of cortical physiology is critical for cognition, but direct local measurement of neuromodulators in vivo is challenging. Choline oxidase (ChOx)-based electrochemical biosensors have been used to capture fast cholinergic signals in behaving animals. However, these transients might be biased by local field potential and O2-evoked enzymatic responses. Using a novel Tetrode-based Amperometric ChOx (TACO) sensor, we performed highly sensitive and selective simultaneous measurement of ChOx activity (COA) and O2. In vitro and in vivo experiments, supported by mathematical modeling, revealed that non-steady-state enzyme responses to O2 give rise to phasic COA dynamics. This mechanism accounts for most of COA transients in the hippocampus, including those following locomotion bouts and sharp-wave/ripples. Our results suggest that it is unfeasible to probe phasic cholinergic signals under most behavioral paradigms with current ChOx biosensors. This confound is generalizable to any oxidase-based biosensor, entailing rigorous controls and new biosensor designs.
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Affiliation(s)
- Ricardo M Santos
- Bernstein Center for Computational Neuroscience, Faculty of Medicine, Ludwig-Maximilians Universität München, Planegg-Martinsried, Germany
| | - Anton Sirota
- Bernstein Center for Computational Neuroscience, Faculty of Medicine, Ludwig-Maximilians Universität München, Planegg-Martinsried, Germany
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5
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Electrochemical Evaluation of a Multi-Site Clinical Depth Recording Electrode for Monitoring Cerebral Tissue Oxygen. MICROMACHINES 2020; 11:mi11070632. [PMID: 32605324 PMCID: PMC7407998 DOI: 10.3390/mi11070632] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/03/2020] [Revised: 06/24/2020] [Accepted: 06/25/2020] [Indexed: 11/23/2022]
Abstract
The intracranial measurement of local cerebral tissue oxygen levels—PbtO2—has become a useful tool for the critical care unit to investigate severe trauma and ischemia injury in patients. Our preliminary work in animal models supports the hypothesis that multi-site depth electrode recording of PbtO2 may give surgeons and critical care providers needed information about brain viability and the capacity for better recovery. Here, we present a surface morphology characterization and an electrochemical evaluation of the analytical properties toward oxygen detection of an FDA-approved, commercially available, clinical grade depth recording electrode comprising 12 Pt recording contacts. We found that the surface of the recording sites is composed of a thin film of smooth Pt and that the electrochemical behavior evaluated by cyclic voltammetry in acidic and neutral electrolyte is typical of polycrystalline Pt surface. The smoothness of the Pt surface was further corroborated by determination of the electrochemical active surface, confirming a roughness factor of 0.9. At an optimal working potential of −0.6 V vs. Ag/AgCl, the sensor displayed suitable values of sensitivity and limit of detection for in vivo PbtO2 measurements. Based on the reported catalytical properties of Pt toward the electroreduction reaction of O2, we propose that these probes could be repurposed for multisite monitoring of PbtO2 in vivo in the human brain.
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Krishna G, Beitchman JA, Bromberg CE, Currier Thomas T. Approaches to Monitor Circuit Disruption after Traumatic Brain Injury: Frontiers in Preclinical Research. Int J Mol Sci 2020; 21:ijms21020588. [PMID: 31963314 PMCID: PMC7014469 DOI: 10.3390/ijms21020588] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2019] [Revised: 01/03/2020] [Accepted: 01/13/2020] [Indexed: 12/19/2022] Open
Abstract
Mild traumatic brain injury (TBI) often results in pathophysiological damage that can manifest as both acute and chronic neurological deficits. In an attempt to repair and reconnect disrupted circuits to compensate for loss of afferent and efferent connections, maladaptive circuitry is created and contributes to neurological deficits, including post-concussive symptoms. The TBI-induced pathology physically and metabolically changes the structure and function of neurons associated with behaviorally relevant circuit function. Complex neurological processing is governed, in part, by circuitry mediated by primary and modulatory neurotransmitter systems, where signaling is disrupted acutely and chronically after injury, and therefore serves as a primary target for treatment. Monitoring of neurotransmitter signaling in experimental models with technology empowered with improved temporal and spatial resolution is capable of recording in vivo extracellular neurotransmitter signaling in behaviorally relevant circuits. Here, we review preclinical evidence in TBI literature that implicates the role of neurotransmitter changes mediating circuit function that contributes to neurological deficits in the post-acute and chronic phases and methods developed for in vivo neurochemical monitoring. Coupling TBI models demonstrating chronic behavioral deficits with in vivo technologies capable of real-time monitoring of neurotransmitters provides an innovative approach to directly quantify and characterize neurotransmitter signaling as a universal consequence of TBI and the direct influence of pharmacological approaches on both behavior and signaling.
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Affiliation(s)
- Gokul Krishna
- Barrow Neurological Institute at Phoenix Children’s Hospital, Phoenix, AZ 85016, USA; (G.K.); (J.A.B.); (C.E.B.)
- Department of Child Health, University of Arizona College of Medicine-Phoenix, Phoenix, AZ 85004, USA
| | - Joshua A. Beitchman
- Barrow Neurological Institute at Phoenix Children’s Hospital, Phoenix, AZ 85016, USA; (G.K.); (J.A.B.); (C.E.B.)
- Department of Child Health, University of Arizona College of Medicine-Phoenix, Phoenix, AZ 85004, USA
- College of Graduate Studies, Midwestern University, Glendale, AZ 85308, USA
| | - Caitlin E. Bromberg
- Barrow Neurological Institute at Phoenix Children’s Hospital, Phoenix, AZ 85016, USA; (G.K.); (J.A.B.); (C.E.B.)
- Department of Child Health, University of Arizona College of Medicine-Phoenix, Phoenix, AZ 85004, USA
| | - Theresa Currier Thomas
- Barrow Neurological Institute at Phoenix Children’s Hospital, Phoenix, AZ 85016, USA; (G.K.); (J.A.B.); (C.E.B.)
- Department of Child Health, University of Arizona College of Medicine-Phoenix, Phoenix, AZ 85004, USA
- Phoenix VA Healthcare System, Phoenix, AZ 85012, USA
- Correspondence: ; Tel.: +1-602-827-2348
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7
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Burmeister JJ, Price DA, Pomerleau F, Huettl P, Quintero JE, Gerhardt GA. Challenges of simultaneous measurements of brain extracellular GABA and glutamate in vivo using enzyme-coated microelectrode arrays. J Neurosci Methods 2020; 329:108435. [PMID: 31600528 PMCID: PMC6924626 DOI: 10.1016/j.jneumeth.2019.108435] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2019] [Revised: 08/19/2019] [Accepted: 09/10/2019] [Indexed: 10/25/2022]
Abstract
BACKGROUND Although GABA is the major inhibitory neurotransmitter in the CNS, quantifying in vivo GABA levels has been challenging. The ability to co-monitor both GABA and the major excitatory neurotransmitter, glutamate, would be a powerful tool in both research and clinical settings. NEW METHOD Ceramic-based microelectrode arrays (MEAs) were used to quantify gamma-aminobutyric acid (GABA) by employing a dual-enzyme reaction scheme including GABase and glutamate oxidase (GluOx). Glutamate was simultaneously quantified on adjacent recording sites coated with GluOx alone. Endogenous glutamate was subtracted from the combined GABA and glutamate signal to yield a pure GABA concentration. RESULTS Electrode sensitivity to GABA in conventional, stirred in vitro calibrations at pH 7.4 did not match the in vivo sensitivity due to diffusional losses. Non-stirred calibrations in agarose or stirred calibrations at pH 8.6 were used to match the in vivo GABA sensitivity. In vivo data collected in the rat brain demonstrated feasibility of the GABA/glutamate MEA including uptake of locally applied GABA, KCl-evoked GABA release and modulation of endogenous GABA with vigabatrin. COMPARISON WITH EXISTING METHODS Implantable enzyme-coated microelectrode arrays have better temporal and spatial resolution than existing off-line methods. However, interpretation of results can be complicated due to the multiple recording site and dual enzyme approach. CONCLUSIONS The initial in vitro and in vivo studies supported that the new MEA configuration may be a viable platform for combined GABA and glutamate measures in the CNS extending the previous reports to in vivo GABA detection. The challenges of this approach are emphasized.
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Affiliation(s)
- Jason J Burmeister
- Department of Neuroscience, Center for Microelectrode Technology, University of Kentucky, College of Medicine, Lexington, KY, USA
| | - David A Price
- Department of Neuroscience, Center for Microelectrode Technology, University of Kentucky, College of Medicine, Lexington, KY, USA
| | - François Pomerleau
- Department of Neuroscience, Center for Microelectrode Technology, University of Kentucky, College of Medicine, Lexington, KY, USA
| | - Peter Huettl
- Department of Neuroscience, Center for Microelectrode Technology, University of Kentucky, College of Medicine, Lexington, KY, USA
| | - Jorge E Quintero
- Department of Neuroscience, Center for Microelectrode Technology, University of Kentucky, College of Medicine, Lexington, KY, USA
| | - Greg A Gerhardt
- Department of Neuroscience, Center for Microelectrode Technology, University of Kentucky, College of Medicine, Lexington, KY, USA.
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8
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Abstract
In vivo electrochemical sensing based on implantable microelectrodes is a strong driving force of analytical neurochemistry in brain. The complex and dynamic neurochemical network sets stringent standards of in vivo electrochemical sensors including high spatiotemporal resolution, selectivity, sensitivity, and minimized disturbance on brain function. Although advanced materials and novel technologies have promoted the development of in vivo electrochemical sensors drastically, gaps with the goals still exist. This Review mainly focuses on recent attempts on the key issues of in vivo electrochemical sensors including selectivity, tissue response and sensing reliability, and compatibility with electrophysiological techniques. In vivo electrochemical methods with bare carbon fiber electrodes, of which the selectivity is achieved either with electrochemical techniques such as fast-scan cyclic voltammetry and differential pulse voltammetry or based on the physiological nature will not be reviewed. Following the elaboration of each issue involved in in vivo electrochemical sensors, possible solutions supported by the latest methodological progress will be discussed, aiming to provide inspiring and practical instructions for future research.
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Affiliation(s)
- Cong Xu
- Key Laboratory of Analytical Chemistry for Living Biosystems, Institute of Chemistry, The Chinese Academy of Sciences, Beijing 100190, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Fei Wu
- Key Laboratory of Analytical Chemistry for Living Biosystems, Institute of Chemistry, The Chinese Academy of Sciences, Beijing 100190, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Ping Yu
- Key Laboratory of Analytical Chemistry for Living Biosystems, Institute of Chemistry, The Chinese Academy of Sciences, Beijing 100190, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Lanqun Mao
- Key Laboratory of Analytical Chemistry for Living Biosystems, Institute of Chemistry, The Chinese Academy of Sciences, Beijing 100190, China
- University of Chinese Academy of Sciences, Beijing 100049, China
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9
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An enzyme-based electrochemical biosensor probe with sensitivity to detect astrocytic versus glioma uptake of glutamate in real time in vitro. Biosens Bioelectron 2018; 126:751-757. [PMID: 30553105 DOI: 10.1016/j.bios.2018.11.023] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2018] [Revised: 11/03/2018] [Accepted: 11/15/2018] [Indexed: 12/31/2022]
Abstract
Glutamate, a major excitatory neurotransmitter in the central nervous system, is essential for regulation of thought, movement, memory, and other higher functions controlled by the brain. Dysregulation of glutamate signaling is associated with severe neuropathological conditions, such as epilepsy, and glioma, a form of brain cancer. Glutamate signals are currently detected by several types of neurochemical probes ranging from microdialysis-based to enzyme-based carbon fiber microsensors. However, an important technology gap exists in the ability to measure glutamate dynamics continuously, and in real time, and from multiple locations in the brain, which limits our ability to further understand the involved spatiotemporal mechanisms of underlying neuropathologies. To overcome this limitation, we developed an enzymatic glutamate microbiosensor, in the form of a ceramic-substrate enabled platinum microelectrode array, that continuously, in real time, measures changes in glutamate concentration from multiple recording sites. In addition, the developed microbiosensor is almost four-fold more sensitive to glutamate than enzymatic sensors previously reported in the literature. Further analysis of glutamate dynamics recorded by our microbiosensor in cultured astrocytes (control condition) and glioma cells (pathological condition) clearly distinguished normal versus impaired glutamate uptake, respectively. These results confirm that the developed glutamate microbiosensor array can become a useful tool in monitoring and understanding glutamate signaling and its regulation in normal and pathological conditions. Furthermore, the developed microbiosensor can be used to measure the effects of potential therapeutic drugs to treat a range of neurological diseases.
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10
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Campos-Beltrán D, Konradsson-Geuken Å, Quintero JE, Marshall L. Amperometric Self-Referencing Ceramic Based Microelectrode Arrays for D-Serine Detection. BIOSENSORS-BASEL 2018; 8:bios8010020. [PMID: 29509674 PMCID: PMC5872068 DOI: 10.3390/bios8010020] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/01/2018] [Revised: 02/15/2018] [Accepted: 03/02/2018] [Indexed: 01/29/2023]
Abstract
D-serine is the major D-amino acid in the mammalian central nervous system. As the dominant co-agonist of the endogenous synaptic NMDA receptor, D-serine plays a role in synaptic plasticity, learning, and memory. Alterations in D-serine are linked to neuropsychiatric disorders including schizophrenia. Thus, it is of increasing interest to monitor the concentration of D-serine in vivo as a relevant player in dynamic neuron-glia network activity. Here we present a procedure for amperometric detection of D-serine with self-referencing ceramic-based microelectrode arrays (MEAs) coated with D-amino acid oxidase from the yeast Rhodotorulagracilis (RgDAAO). We demonstrate in vitro D-serine recordings with a mean sensitivity of 8.61 ± 0.83 pA/µM to D-serine, a limit of detection (LOD) of 0.17 ± 0.01 µM, and a selectivity ratio of 80:1 or greater for D-serine over ascorbic acid (mean ± SEM; n = 12) that can be used for freely moving studies.
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Affiliation(s)
- Diana Campos-Beltrán
- Institute of Experimental and Clinical Pharmacology and Toxicology, University of Lübeck, Ratzeburger Allee 160, 23562 Lübeck, Germany.
| | - Åsa Konradsson-Geuken
- The Department of Pharmaceutical Biosciences, Uppsala University, 75124 Uppsala, Sweden.
- The Department of Physiology and Pharmacology, Karolinska Institutet, 17177 Stockholm, Sweden.
| | - Jorge E Quintero
- CenMeT, University of Kentucky, Lexington, 40506 KY, USA.
- Quanteon LLC, Nicholasville, 40356 KY, USA.
| | - Lisa Marshall
- Institute of Experimental and Clinical Pharmacology and Toxicology, University of Lübeck, Ratzeburger Allee 160, 23562 Lübeck, Germany.
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11
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Ledo A, Lourenço CF, Laranjinha J, Gerhardt GA, Barbosa RM. Combined in Vivo Amperometric Oximetry and Electrophysiology in a Single Sensor: A Tool for Epilepsy Research. Anal Chem 2017; 89:12383-12390. [DOI: 10.1021/acs.analchem.7b03452] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Affiliation(s)
- Ana Ledo
- Center
for Neuroscience and Cell Biology, University of Coimbra, Rua Larga, 3004-504 Coimbra, Portugal
- BrainSense, Limitada, Biocant Park, 3060-197 Cantanhede, Portugal
| | - Cátia F. Lourenço
- Center
for Neuroscience and Cell Biology, University of Coimbra, Rua Larga, 3004-504 Coimbra, Portugal
| | - João Laranjinha
- Center
for Neuroscience and Cell Biology, University of Coimbra, Rua Larga, 3004-504 Coimbra, Portugal
- Faculty
of Pharmacy, University of Coimbra, Azinhaga de Santa Coimbra, 3000-548 Coimbra, Portugal
| | - Greg A. Gerhardt
- Center for Microelectrode
Technology, Department of Neuroscience, University of Kentucky Medical Center, Lexington, Kentucky 40536, United States
| | - Rui M. Barbosa
- Center
for Neuroscience and Cell Biology, University of Coimbra, Rua Larga, 3004-504 Coimbra, Portugal
- Faculty
of Pharmacy, University of Coimbra, Azinhaga de Santa Coimbra, 3000-548 Coimbra, Portugal
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12
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Lourenço CF, Ledo A, Gerhardt GA, Laranjinha J, Barbosa RM. Neurometabolic and electrophysiological changes during cortical spreading depolarization: multimodal approach based on a lactate-glucose dual microbiosensor arrays. Sci Rep 2017; 7:6764. [PMID: 28754993 PMCID: PMC5533760 DOI: 10.1038/s41598-017-07119-6] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2017] [Accepted: 06/21/2017] [Indexed: 12/24/2022] Open
Abstract
Spreading depolarization (SD) is a slow propagating wave of strong depolarization of neural cells, implicated in several neuropathological conditions. The breakdown of brain homeostasis promotes significant hemodynamic and metabolic alterations, which impacts on neuronal function. In this work we aimed to develop an innovative multimodal approach, encompassing metabolic, electric and hemodynamic measurements, tailored but not limited to study SD. This was based on a novel dual-biosensor based on microelectrode arrays designed to simultaneously monitor lactate and glucose fluctuations and ongoing neuronal activity with high spatial and temporal resolution. In vitro evaluation of dual lactate-glucose microbiosensor revealed an extended linear range, high sensitivity and selectivity, fast response time and low oxygen-, temperature- and pH- dependencies. In anesthetized rats, we measured with the same array a significant drop in glucose concentration matched to a rise in lactate and concurrently with pronounced changes in the spectral profile of LFP-related currents during episodes of mechanically-evoked SD. This occurred along with the stereotypical hemodynamic response of the SD wave. Overall, this multimodal approach successfully demonstrates the capability to monitor metabolic alterations and ongoing electrical activity, thus contributing to a better understanding of the metabolic changes occurring in the brain following SD.
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Affiliation(s)
- Cátia F Lourenço
- Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal.
| | - Ana Ledo
- Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal
| | - Greg A Gerhardt
- Center for Microelectrode Technology, University of Kentucky, Lexington, USA
| | - João Laranjinha
- Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal.,Faculty of Pharmacy, University of Coimbra, Coimbra, Portugal
| | - Rui M Barbosa
- Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal. .,Faculty of Pharmacy, University of Coimbra, Coimbra, Portugal.
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13
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Kealy J, Commins S, Lowry JP. The effect of NMDA-R antagonism on simultaneously acquired local field potentials and tissue oxygen levels in the brains of freely-moving rats. Neuropharmacology 2017; 116:343-350. [DOI: 10.1016/j.neuropharm.2017.01.006] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2016] [Revised: 12/07/2016] [Accepted: 01/09/2017] [Indexed: 12/14/2022]
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14
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Abstract
The cortical cholinergic input system has been described as a neuromodulator system that influences broadly defined behavioral and brain states. The discovery of phasic, trial-based increases in extracellular choline (transients), resulting from the hydrolysis of newly released acetylcholine (ACh), in the cortex of animals reporting the presence of cues suggests that ACh may have a more specialized role in cognitive processes. Here we expressed channelrhodopsin or halorhodopsin in basal forebrain cholinergic neurons of mice with optic fibers directed into this region and prefrontal cortex. Cholinergic transients, evoked in accordance with photostimulation parameters determined in vivo, were generated in mice performing a task necessitating the reporting of cue and noncue events. Generating cholinergic transients in conjunction with cues enhanced cue detection rates. Moreover, generating transients in noncued trials, where cholinergic transients normally are not observed, increased the number of invalid claims for cues. Enhancing hits and generating false alarms both scaled with stimulation intensity. Suppression of endogenous cholinergic activity during cued trials reduced hit rates. Cholinergic transients may be essential for synchronizing cortical neuronal output driven by salient cues and executing cue-guided responses.
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15
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Disney AA, McKinney C, Grissom L, Lu X, Reynolds JH. A multi-site array for combined local electrochemistry and electrophysiology in the non-human primate brain. J Neurosci Methods 2015; 255:29-37. [PMID: 26226654 DOI: 10.1016/j.jneumeth.2015.07.009] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2015] [Accepted: 07/13/2015] [Indexed: 12/30/2022]
Abstract
BACKGROUND Currently, the primary technique employed in circuit-level study of the brain is electrophysiology, recording local field or action potentials (LFPs or APs). However most communication between neurons is chemical and the relationship between electrical activity within neurons and chemical signaling between them is not well understood in vivo, particularly for molecules that signal at least in part by non-synaptic transmission. NEW METHOD We describe a multi-contact array and accompanying head stage circuit that together enable concurrent electrophysiological and electrochemical recording. The array is small (<200 μm) and can be assembled into a device of arbitrary length. It is therefore well-suited for use in all major in vivo model systems in neuroscience, including non-human primates where the large brain and need for daily insertion and removal of recording devices places particularly strict demands on design. RESULTS We present a protocol for array fabrication. We then show that a device built in the manner described can record LFPs and perform enzyme-based amperometric detection of choline in the awake macaque monkey. Comparison with existing methods Existing methods allow single mode (electrophysiology or electrochemistry) recording. This system is designed for concurrent, dual-mode recording. It is also the only system designed explicitly to meet the challenges of recording in non-human primates. CONCLUSIONS Our system offers the possibility for conducting in vivo studies in a range of species that examine the relationship between the electrical activity of neurons and their chemical environment, with exquisite spatial and temporal precision.
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Affiliation(s)
- Anita A Disney
- Systems Neurobiology Laboratories, The Salk Institute for Biological Studies, La Jolla, CA, USA.
| | - Collin McKinney
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Larry Grissom
- California Institute for Telecommunications and Information Technology (CalIT2), University of California San Diego, La Jolla, CA, USA
| | - Xuekun Lu
- California Institute for Telecommunications and Information Technology (CalIT2), University of California San Diego, La Jolla, CA, USA
| | - John H Reynolds
- Systems Neurobiology Laboratories, The Salk Institute for Biological Studies, La Jolla, CA, USA
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Simultaneous measurement of cholinergic tone and neuronal network dynamics in vivo in the rat brain using a novel choline oxidase based electrochemical biosensor. Biosens Bioelectron 2015; 69:83-94. [DOI: 10.1016/j.bios.2015.02.003] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2014] [Revised: 02/03/2015] [Accepted: 02/04/2015] [Indexed: 12/11/2022]
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17
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Decreased subcortical cholinergic arousal in focal seizures. Neuron 2015; 85:561-72. [PMID: 25654258 DOI: 10.1016/j.neuron.2014.12.058] [Citation(s) in RCA: 89] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2014] [Revised: 11/18/2014] [Accepted: 12/17/2014] [Indexed: 11/20/2022]
Abstract
Impaired consciousness in temporal lobe seizures has a major negative impact on quality of life. The prevailing view holds that this disorder impairs consciousness by seizure spread to the bilateral temporal lobes. We propose instead that seizures invade subcortical regions and depress arousal, causing impairment through decreases rather than through increases in activity. Using functional magnetic resonance imaging in a rodent model, we found increased activity in regions known to depress cortical function, including lateral septum and anterior hypothalamus. Importantly, we found suppression of intralaminar thalamic and brainstem arousal systems and suppression of the cortex. At a cellular level, we found reduced firing of identified cholinergic neurons in the brainstem pedunculopontine tegmental nucleus and basal forebrain. Finally, we used enzyme-based amperometry to demonstrate reduced cholinergic neurotransmission in both cortex and thalamus. Decreased subcortical arousal is a critical mechanism for loss of consciousness in focal temporal lobe seizures.
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18
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Hinzman JM, DiNapoli VA, Mahoney EJ, Gerhardt GA, Hartings JA. Spreading depolarizations mediate excitotoxicity in the development of acute cortical lesions. Exp Neurol 2015; 267:243-53. [PMID: 25819105 DOI: 10.1016/j.expneurol.2015.03.014] [Citation(s) in RCA: 73] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2015] [Revised: 03/09/2015] [Accepted: 03/17/2015] [Indexed: 11/19/2022]
Abstract
Spreading depolarizations (SD) are mass depolarizations of neurons and astrocytes that occur spontaneously in acute brain injury and mediate time-dependent lesion growth. Glutamate excitotoxicity has also been extensively studied as a mechanism of neuronal injury, although its relevance to in vivo pathology remains unclear. Here we hypothesized that excitotoxicity in acute lesion development occurs only as a consequence of SD. Using glutamate-sensitive microelectrodes, we found that SD induced by KCl in normal rat cortex elicits increases in extracellular glutamate (11.6±1.3μM) that are synchronous with the onset, sustainment, and resolution of the extracellular direct-current shift of SD. Inhibition of glutamate uptake with d,l-threo-β-benzyloxyaspartate (TBOA, 0.5 and 1mM) significantly prolonged the duration of the direct-current shift (148% and 426%, respectively) and the glutamate increase (167% and 374%, respectively) in a dose-dependent manner (P<0.05). These prolonged events produced significant cortical lesions as indicated by Fluoro-Jade staining (P<0.05), while no lesions were observed after SD in control conditions or after cortical injection of 1mM glutamate (extracellular increase: 243±50.8μM) or 0.5mM TBOA (glutamate increase: 8.5±1.6μM) without SD. We then used an embolic focal ischemia model to determine whether glutamate elevations occur independent of SD in the natural evolution of a cortical lesion. In both the ischemic core and penumbra, glutamate increased only in synchrony with anoxic terminal SD (6.1±1.1μM) and transient SDs (11.8±2.4μM), and not otherwise. Delayed terminal SDs were also observed in two animals at 98 and 150min after ischemic onset and induced similar glutamate elevations. Durations of SDs and glutamate increases were significantly correlated in both normal and ischemic animals (P<0.05). These data suggest that pathologically prolonged SDs are a required mechanism of acute cortical lesion development and that glutamate elevations and the mass electrochemical changes of SD and are merely different facets of the same pathophysiologic process.
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Affiliation(s)
- Jason M Hinzman
- Department of Neurosurgery, University of Cincinnati (UC) College of Medicine and Neurotrauma Center at UC Neuroscience Institute, Cincinnati, OH, USA.
| | - Vince A DiNapoli
- Department of Neurosurgery, University of Cincinnati (UC) College of Medicine and Neurotrauma Center at UC Neuroscience Institute, Cincinnati, OH, USA; Mayfield Clinic, Cincinnati, OH, USA
| | - Eric J Mahoney
- Department of Neurosurgery, University of Cincinnati (UC) College of Medicine and Neurotrauma Center at UC Neuroscience Institute, Cincinnati, OH, USA
| | - Greg A Gerhardt
- Department of Anatomy and Neurobiology, University of Kentucky Chandler Medical Center, Morris K. Udall Parkinson's Disease Research Center of Excellence, Center for Microelectrode Technology, Spinal Cord and Brain Injury Research Center, Lexington, KY, USA
| | - Jed A Hartings
- Department of Neurosurgery, University of Cincinnati (UC) College of Medicine and Neurotrauma Center at UC Neuroscience Institute, Cincinnati, OH, USA; Mayfield Clinic, Cincinnati, OH, USA
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19
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Li W, Motelow JE, Zhan Q, Hu YC, Kim R, Chen WC, Blumenfeld H. Cortical network switching: possible role of the lateral septum and cholinergic arousal. Brain Stimul 2014; 8:36-41. [PMID: 25440289 DOI: 10.1016/j.brs.2014.09.003] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2014] [Revised: 07/22/2014] [Accepted: 09/05/2014] [Indexed: 10/24/2022] Open
Abstract
BACKGROUND Cortical networks undergo large-scale switching between states of increased or decreased activity in normal sleep and cognition as well as in pathological conditions such as epilepsy. We previously found that focal hippocampal seizures in rats induce increased neuronal firing and cerebral blood flow in subcortical structures including the lateral septal area, along with frontal cortical slow oscillations resembling slow wave sleep. In addition, stimulation of the lateral septum in the absence of a seizure resulted in cortical deactivation with slow oscillations. HYPOTHESIS We hypothesized that lateral septal activation might cause neocortical deactivation indirectly, possibly through impaired subcortical arousal. But how does subcortical stimulation cause slow wave activity in frontal cortex? How do arousal neurotransmitter levels (e.g. acetylcholine) change in cortex during the excitation of inhibitory projection nuclei? METHODS AND RESULTS In the current study, we used simultaneous electrophysiology and enzyme-based amperometry in a rat model, and found a decrease in choline, along with slow wave activity in orbital frontal cortex during lateral septal stimulation in the absence of seizures. In contrast, the choline signal and local field potential in frontal cortex had no significant changes when stimulating the hippocampus, but showed increased choline and decreased slow wave activity with an arousal stimulus produced by toe pinch. CONCLUSIONS These findings indicate that the activation of subcortical inhibitory structures (such as lateral septum) can depress subcortical cholinergic arousal. This mechanism may play an important role in large-scale transitions of cortical activity in focal seizures, as well as in normal cortical function.
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Affiliation(s)
- Wei Li
- Department of Neurology, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06520, USA; Department of Neurosurgery, Jinling Hospital, School of Medicine, Nanjing University, 305 East Zhongshan Road, Nanjing 210002, Jiangsu Province, China
| | - Joshua E Motelow
- Department of Neurology, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06520, USA
| | - Qiong Zhan
- Department of Neurology, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06520, USA; Department of Neurology, Xiangya Hospital, Central South University, Changsha, Hunan 410008, China
| | - Yang-Chun Hu
- Department of Neurology, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06520, USA; Department of Neurosurgery, Jinling Hospital, School of Medicine, Nanjing University, 305 East Zhongshan Road, Nanjing 210002, Jiangsu Province, China
| | - Robert Kim
- Department of Neurology, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06520, USA
| | - William C Chen
- Department of Neurology, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06520, USA
| | - Hal Blumenfeld
- Department of Neurology, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06520, USA; Department of Neurobiology, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06520, USA; Department of Neurosurgery, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06520, USA.
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20
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Hascup KN, Hascup ER. Electrochemical techniques for subsecond neurotransmitter detection in live rodents. Comp Med 2014; 64:249-55. [PMID: 25296011 PMCID: PMC4170089] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2013] [Revised: 11/12/2013] [Accepted: 01/09/2014] [Indexed: 06/03/2023]
Abstract
Alterations in neurotransmission have been implicated in numerous neurodegenerative and neuropsychiatric disorders, including Alzheimer disease, Parkinson disease, epilepsy, and schizophrenia. Unfortunately, few techniques support the measurement of real-time changes in neurotransmitter levels over multiple days, as is essential for ethologic and pharmacodynamic testing. Microdialysis is commonly used for these research paradigms, but its poor temporal and spatial resolution make this technique inadequate for measuring the rapid dynamics (milliseconds to seconds) of fast signaling neurotransmitters, such as glutamate and acetylcholine. Enzymatic microelectrode arrays (biosensors) coupled with electrochemical recording techniques have demonstrated fast temporal resolution (less than 1 s), excellent spatial resolution (micron-scale), low detection limits (≤200 nM), and minimal damage (50 to 100 μm) to surrounding brain tissue. Here we discuss the benefits, methods, and animal welfare considerations of using platinum microelectrodes on a ceramic substrate for enzyme-based electrochemical recording techniques for real-time in vivo neurotransmitter recordings in both anesthetized and awake, freely moving rodents.
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Affiliation(s)
- Kevin N Hascup
- Departments of Neurology and Pharmacology, Center for Alzheimer's Disease and Related Disorders, Southern Illinois University School of Medicine, Springfield, Illinois, USA
| | - Erin R Hascup
- Departments of Neurology and Pharmacology, Center for Alzheimer's Disease and Related Disorders, Southern Illinois University School of Medicine, Springfield, Illinois, USA.
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21
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Maucler C, Pernot P, Vasylieva N, Pollegioni L, Marinesco S. In vivo D-serine hetero-exchange through alanine-serine-cysteine (ASC) transporters detected by microelectrode biosensors. ACS Chem Neurosci 2013; 4:772-81. [PMID: 23581544 DOI: 10.1021/cn4000549] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
D-serine, a co-agonist of N-methyl D-aspartate (NMDA) receptors, has been implicated in neurological and psychiatric disorders such as cerebral ischemia, lateral amyotrophic sclerosis, or schizophrenia. D-serine signaling represents an important pharmacological target for treating these diseases; however, the biochemical mechanisms controlling extracellular D-serine levels in vivo are still unclear. D-serine heteroexchange through small neutral amino acid transporters has been shown in cell cultures and brain slices and could provide a biochemical mechanism for the control of D-serine extracellular concentration in vivo. Alternatively, exocytotic D-serine release has also been proposed. In this study, the dynamics of D-serine release and clearance were explored in vivo on a second-by-second time scale using microelectrode biosensors. The rate of D-serine clearance in the rat frontal cortex after a microionophoretic injection revealed a transporter-mediated uptake mechanism. D-serine uptake was blocked by small neutral l-amino acids, implicating alanine-serine-cysteine (ASC) transporters, in particular high affinity Asc-1 and low affinity ASCT2 transporters. Interestingly, changes in alanine, serine, or threonine levels resulted in D-serine release through ASC transporters. Asc-1, but not ASCT2, appeared to release D-serine in response to changes in amino acid concentrations. Finally, neuronal silencing by tetrodotoxin increased D-serine extracellular concentration by an ASC-transporter-dependent mechanism. Together, these results indicate that D-serine heteroexchange through ASC transporters is present in vivo and may constitute a key component in the regulation of D-serine extracellular concentration.
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Affiliation(s)
- Caroline Maucler
- INSERM U1028; CNRS UMR5292 Lyon Neuroscience Research Center, AniRA-Neurochem technological platform, team WAKING, Lyon F-69000, France
- Université Claude Bernard Lyon 1, Lyon F-69000, France
| | - Pierre Pernot
- INSERM U1028; CNRS UMR5292 Lyon Neuroscience Research Center, AniRA-Neurochem technological platform, team WAKING, Lyon F-69000, France
- Université Claude Bernard Lyon 1, Lyon F-69000, France
| | - Natalia Vasylieva
- INSERM U1028; CNRS UMR5292 Lyon Neuroscience Research Center, AniRA-Neurochem technological platform, team WAKING, Lyon F-69000, France
- Université Claude Bernard Lyon 1, Lyon F-69000, France
- Institut de nanotechnologie de Lyon, CNRS UMR-5270, INSA de Lyon, France
| | - Loredano Pollegioni
- Dipartimento di Biotecnologie e Scienze della Vita, Università degli studi dell’Insubria, Varese, Italy
- “The Protein Factory”, Centro Interuniversitario di Ricerca in Biotecnologie Proteiche ICRM-CNR Milano, Politecnico di Milano and Università degli studi dell’Insubria, Italy
| | - Stéphane Marinesco
- INSERM U1028; CNRS UMR5292 Lyon Neuroscience Research Center, AniRA-Neurochem technological platform, team WAKING, Lyon F-69000, France
- Université Claude Bernard Lyon 1, Lyon F-69000, France
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22
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Hascup KN, Hascup ER, Littrell OM, Hinzman JM, Werner CE, Davis VA, Burmeister JJ, Pomerleau F, Quintero JE, Huettl P, Gerhardt GA. Microelectrode Array Fabrication and Optimization for Selective Neurochemical Detection. NEUROMETHODS 2013. [DOI: 10.1007/978-1-62703-370-1_2] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
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23
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Hascup ER, Hascup KN, Talauliker PM, Price DA, Pomerleau F, Quintero JE, Huettl P, Gratton A, Strömberg I, Gerhardt GA. Sub-Second Measurements of Glutamate and Other Neurotransmitter Signaling Using Enzyme-Based Ceramic Microelectrode Arrays. NEUROMETHODS 2013. [DOI: 10.1007/978-1-62703-370-1_8] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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24
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Viggiano A, Marinesco S, Pain F, Meiller A, Gurden H. Reconstruction of field excitatory post-synaptic potentials in the dentate gyrus from amperometric biosensor signals. J Neurosci Methods 2012; 206:1-6. [DOI: 10.1016/j.jneumeth.2012.01.013] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2011] [Revised: 01/24/2012] [Accepted: 01/25/2012] [Indexed: 11/30/2022]
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25
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Spatiotemporal coupling between hippocampal acetylcholine release and theta oscillations in vivo. J Neurosci 2010; 30:13431-40. [PMID: 20926669 DOI: 10.1523/jneurosci.1144-10.2010] [Citation(s) in RCA: 87] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Both acetylcholine (ACh) and theta oscillations are important for learning and memory, but the dynamic interaction between these two processes remains unclear. Recent advances in amperometry techniques have revealed phasic ACh releases in vivo. However, it is unknown whether phasic ACh release co-occurs with theta oscillations. We investigated this issue in the CA1 region of urethane-anesthetized male rats using amperometric and electrophysiological recordings. We found that ACh release was highly correlated with the appearance of both spontaneous and induced theta oscillations. Moreover, the maximal ACh release was observed around or slightly above the pyramidal layer. Interestingly, such release lagged behind theta initiation by 25-60 s. The slow ACh release profile was matched by the slow firing rate increase of a subset of medial-septal low-firing-rate neurons. Together, these results establish, for the first time, the in vivo coupling between phasic ACh release and theta oscillations on spatiotemporal scales much finer than previously known. These findings also suggest that phasic ACh is not required for theta initiation and may instead operate synergistically with theta oscillations to promote neural plasticity in the service of learning and memory.
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26
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Bokil H, Andrews P, Kulkarni JE, Mehta S, Mitra PP. Chronux: a platform for analyzing neural signals. J Neurosci Methods 2010; 192:146-51. [PMID: 20637804 DOI: 10.1016/j.jneumeth.2010.06.020] [Citation(s) in RCA: 573] [Impact Index Per Article: 40.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2010] [Revised: 06/18/2010] [Accepted: 06/21/2010] [Indexed: 10/19/2022]
Abstract
Chronux is an open-source software package developed for the analysis of neural data. The current version of Chronux includes software for signal processing of neural time-series data including several specialized mini-packages for spike-sorting, local regression, audio segmentation, and other data-analysis tasks typically encountered by a neuroscientist. Chronux is freely available along with user tutorials, sample data, and extensive documentation from http://chronux.org/.
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Affiliation(s)
- Hemant Bokil
- Medametrics LLC, 42 West 24th Street, New York, NY 10010, United States.
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27
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Stephens ML, Pomerleau F, Huettl P, Gerhardt GA, Zhang Z. Real-time glutamate measurements in the putamen of awake rhesus monkeys using an enzyme-based human microelectrode array prototype. J Neurosci Methods 2009; 185:264-72. [PMID: 19850078 DOI: 10.1016/j.jneumeth.2009.10.008] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2009] [Revised: 10/11/2009] [Accepted: 10/11/2009] [Indexed: 11/19/2022]
Abstract
Commonly used for research studies in the central nervous system, microdialysis has revealed a link between dysregulation of the excitatory neurotransmitter glutamate and ischemia and seizure, however limitations like slow temporal resolution have stalled the advancement of microdialysis as a diagnostic tool. We have developed and extensively characterized an enzyme-based microelectrode array technology for second-by-second in vivo amperometric measurements of glutamate in the mammalian CNS. The current studies demonstrated the ability of a human microelectrode array prototype (Spencer-Gerhardt-2 (SG-2)) to measure tonic and phasic glutamate neurotransmission in the putamen of unanesthetized non-human primates. We also showed that the SG-2 remains functional following sterilization. Ability to monitor dynamic changes in glutamate in real-time may assist the development of clinical algorithms to potentially alert care-providers prior to onset of overt ischemia or seizure, or provide neurosurgeons with second-by-second measurements of rapid changes in extracellular glutamate which could help guide surgical procedures or aid in interventional strategies.
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Affiliation(s)
- Michelle L Stephens
- Department of Anatomy and Neurobiology, University of Kentucky Chandler Medical Center, Lexington, KY 40536-0098, USA
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