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Xu M, Zhao Y, Xu G, Zhang Y, Sun S, Sun Y, Wang J, Pei R. Recent Development of Neural Microelectrodes with Dual-Mode Detection. BIOSENSORS 2022; 13:59. [PMID: 36671894 PMCID: PMC9856135 DOI: 10.3390/bios13010059] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/06/2022] [Revised: 12/24/2022] [Accepted: 12/28/2022] [Indexed: 06/17/2023]
Abstract
Neurons communicate through complex chemical and electrophysiological signal patterns to develop a tight information network. A physiological or pathological event cannot be explained by signal communication mode. Therefore, dual-mode electrodes can simultaneously monitor the chemical and electrophysiological signals in the brain. They have been invented as an essential tool for brain science research and brain-computer interface (BCI) to obtain more important information and capture the characteristics of the neural network. Electrochemical sensors are the most popular methods for monitoring neurochemical levels in vivo. They are combined with neural microelectrodes to record neural electrical activity. They simultaneously detect the neurochemical and electrical activity of neurons in vivo using high spatial and temporal resolutions. This paper systematically reviews the latest development of neural microelectrodes depending on electrode materials for simultaneous in vivo electrochemical sensing and electrophysiological signal recording. This includes carbon-based microelectrodes, silicon-based microelectrode arrays (MEAs), and ceramic-based MEAs, focusing on the latest progress since 2018. In addition, the structure and interface design of various types of neural microelectrodes have been comprehensively described and compared. This could be the key to simultaneously detecting electrochemical and electrophysiological signals.
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Affiliation(s)
- Meng Xu
- CAS Key Laboratory for Nano-Bio Interface, Division of Nano-biomedicine, Suzhou Institute of Nano-Tech and Nano-Bionics (SINANO), Chinese Academy of Sciences, Suzhou 215123, China
- School of Nano-Tech and Nano-Bionics, University of Science and Technology of China (USTC), Hefei 230026, China
| | - Yuewu Zhao
- CAS Key Laboratory for Nano-Bio Interface, Division of Nano-biomedicine, Suzhou Institute of Nano-Tech and Nano-Bionics (SINANO), Chinese Academy of Sciences, Suzhou 215123, China
| | - Guanghui Xu
- School of Nano-Tech and Nano-Bionics, University of Science and Technology of China (USTC), Hefei 230026, China
| | - Yuehu Zhang
- CAS Key Laboratory for Nano-Bio Interface, Division of Nano-biomedicine, Suzhou Institute of Nano-Tech and Nano-Bionics (SINANO), Chinese Academy of Sciences, Suzhou 215123, China
- School of Nano-Tech and Nano-Bionics, University of Science and Technology of China (USTC), Hefei 230026, China
| | - Shengkai Sun
- CAS Key Laboratory for Nano-Bio Interface, Division of Nano-biomedicine, Suzhou Institute of Nano-Tech and Nano-Bionics (SINANO), Chinese Academy of Sciences, Suzhou 215123, China
| | - Yan Sun
- CAS Key Laboratory for Nano-Bio Interface, Division of Nano-biomedicine, Suzhou Institute of Nano-Tech and Nano-Bionics (SINANO), Chinese Academy of Sciences, Suzhou 215123, China
- School of Nano-Tech and Nano-Bionics, University of Science and Technology of China (USTC), Hefei 230026, China
| | - Jine Wang
- CAS Key Laboratory for Nano-Bio Interface, Division of Nano-biomedicine, Suzhou Institute of Nano-Tech and Nano-Bionics (SINANO), Chinese Academy of Sciences, Suzhou 215123, China
- School of Nano-Tech and Nano-Bionics, University of Science and Technology of China (USTC), Hefei 230026, China
| | - Renjun Pei
- CAS Key Laboratory for Nano-Bio Interface, Division of Nano-biomedicine, Suzhou Institute of Nano-Tech and Nano-Bionics (SINANO), Chinese Academy of Sciences, Suzhou 215123, China
- School of Nano-Tech and Nano-Bionics, University of Science and Technology of China (USTC), Hefei 230026, China
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2
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Liu R, Feng ZY, Li D, Jin B, Yan Lan, Meng LY. Recent trends in carbon-based microelectrodes as electrochemical sensors for neurotransmitter detection: A review. Trends Analyt Chem 2022. [DOI: 10.1016/j.trac.2022.116541] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
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3
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Sung C, Jeon W, Nam KS, Kim Y, Butt H, Park S. Multimaterial and multifunctional neural interfaces: from surface-type and implantable electrodes to fiber-based devices. J Mater Chem B 2020; 8:6624-6666. [DOI: 10.1039/d0tb00872a] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Development of neural interfaces from surface electrodes to fibers with various type, functionality, and materials.
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Affiliation(s)
- Changhoon Sung
- Department of Bio and Brain Engineering
- Korea Advanced Institute of Science and Technology (KAIST)
- Daejeon 34141
- Republic of Korea
| | - Woojin Jeon
- Department of Bio and Brain Engineering
- Korea Advanced Institute of Science and Technology (KAIST)
- Daejeon 34141
- Republic of Korea
| | - Kum Seok Nam
- School of Electrical Engineering
- Korea Advanced Institute of Science and Technology (KAIST)
- Daejeon 34141
- Republic of Korea
| | - Yeji Kim
- Department of Bio and Brain Engineering
- Korea Advanced Institute of Science and Technology (KAIST)
- Daejeon 34141
- Republic of Korea
| | - Haider Butt
- Department of Mechanical Engineering
- Khalifa University
- Abu Dhabi 127788
- United Arab Emirates
| | - Seongjun Park
- Department of Bio and Brain Engineering
- Korea Advanced Institute of Science and Technology (KAIST)
- Daejeon 34141
- Republic of Korea
- KAIST Institute for Health Science and Technology (KIHST)
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4
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Scida K, Plaxco KW, Jamieson BG. High frequency, real-time neurochemical and neuropharmacological measurements in situ in the living body. Transl Res 2019; 213:50-66. [PMID: 31361988 DOI: 10.1016/j.trsl.2019.07.004] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/28/2019] [Revised: 05/20/2019] [Accepted: 07/11/2019] [Indexed: 12/18/2022]
Abstract
The beautiful and complex brain machinery is perfectly synchronized, and our bodies have evolved to protect it against a myriad of potential threats. Shielded physically by the skull and chemically by the blood brain barrier, the brain processes internal and external information so that we can efficiently relate to the world that surrounds us while simultaneously and unconsciously controlling our vital functions. When coupled with the brittle nature of its internal chemical and electric signals, the brain's "armor" render accessing it a challenging and delicate endeavor that has historically limited our understanding of its structural and neurochemical intricacies. In this review, we briefly summarize the advancements made over the past 10 years to decode the brain's neurochemistry and neuropharmacology in situ, at the site of interest in the brain, with special focus on what we consider game-changing emerging technologies (eg, genetically encoded indicators and electrochemical aptamer-based sensors) and the challenges these must overcome before chronic, in situ chemosensing measurements become routine.
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Affiliation(s)
- Karen Scida
- Diagnostic Biochips, Inc., Glen Burnie, Maryland
| | - Kevin W Plaxco
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, California
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Asri R, O'Neill B, Patel JC, Siletti KA, Rice ME. Detection of evoked acetylcholine release in mouse brain slices. Analyst 2018; 141:6416-6421. [PMID: 27722568 DOI: 10.1039/c6an01758d] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The study of transmitter interactions in reward and motor pathways in the brain, including the striatum, requires methodology to detect stimulus-driven neurotransmitter release events. Such methods exist for dopamine, and have contributed to the understanding of local and behavioral factors that regulate dopamine release. However, factors that regulate release of another key transmitter in these pathways, acetylcholine (ACh), are unresolved, in part because of limited temporal and spatial resolution of current detection methods. We have optimized a voltammetric method for detection of local stimulus-evoked ACh release using enzyme-coated carbon-fiber microelectrodes and fast-scan cyclic voltammetry. These electrodes are based on the detection of H2O2 generated by the actions of acetylcholine esterase and choline oxidase, and reliably respond to ACh in a concentration-dependent manner. Methods for enzyme coating were optimized for mechanical stability that allowed for their use in ex vivo brain slices. We report here the first quantitative assessment of extracellular ACh concentration after local electrical stimulation in dorsal striatum in slices from control mice. The selective detection of ACh under these conditions was confirmed by showing that the response detected in the control slices was absent in slices from mice bred to lack ACh synthesis in the forebrain. These electrodes represent a new tool to study ACh and ACh-dopamine interactions with micrometer spatial resolution.
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Affiliation(s)
- R Asri
- New York University School of Medicine, Department of Neurosurgery, Department of Neuroscience and Physiology, 550 First Avenue, New York, NY 10016, USA.
| | - B O'Neill
- New York University School of Medicine, Department of Neurosurgery, Department of Neuroscience and Physiology, 550 First Avenue, New York, NY 10016, USA.
| | - J C Patel
- New York University School of Medicine, Department of Neurosurgery, Department of Neuroscience and Physiology, 550 First Avenue, New York, NY 10016, USA.
| | - K A Siletti
- New York University School of Medicine, Department of Neurosurgery, Department of Neuroscience and Physiology, 550 First Avenue, New York, NY 10016, USA.
| | - M E Rice
- New York University School of Medicine, Department of Neurosurgery, Department of Neuroscience and Physiology, 550 First Avenue, New York, NY 10016, USA.
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Patrick MM, Grillot JM, Derden ZM, Paul DW. Long-term Drifts in Sensitivity Caused by Biofouling of an Amperometric Oxygen Sensor. ELECTROANAL 2016. [DOI: 10.1002/elan.201600653] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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7
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Bailey MR, Martin RS, Schultz ZD. Role of Surface Adsorption in the Surface-Enhanced Raman Scattering and Electrochemical Detection of Neurotransmitters. THE JOURNAL OF PHYSICAL CHEMISTRY. C, NANOMATERIALS AND INTERFACES 2016; 120:20624-20633. [PMID: 27840665 PMCID: PMC5100693 DOI: 10.1021/acs.jpcc.6b01196] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
The strength of the analyte-substrate interaction is a key component when evaluating the observed enhancements in surface-enhanced Raman scattering (SERS) detection. By performing Raman and electrochemical measurements on a series of neurotransmitters, including dopamine, serotonin, norepinephrine, and epinephrine, as well as catechol as it allows us to examine the diol moiety without the side chains present, we were able to correlate surface chemistry with the measured SERS signal and examine the oxidation mechanism of each analyte. Finite element simulations of fluid flow, mass transport, and Langmuir adsorption to a surface in a microchannel were used to expand on the experiments. By holding kads constant and changing kdes, Keq was varied systematically to elucidate how the adsorption kinetics change for different molecular adsorbates. The modeling indicates that the largest surface concentration is observed from the analyte with the strongest affinity for the surface in both the continuous flow and time dependent injection scenarios. The COMSOL model of varying surface concentration explains differences observed in integrated current during amperometry and signal intensities in SERS measurements. This combination of results indicates that molecular structure and surface affinity influence the sensitivity in SERS, such that the species with the strongest affinity for the surface has the highest signal-to-noise in the SERS experiments in flowing solutions.
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Affiliation(s)
- Matthew R. Bailey
- University of Notre Dame, Department of Chemistry and Biochemistry, NotreDame, IN 46556
| | - R. Scott Martin
- Saint Louis University, Department of Chemistry, St. Louis, MO 63103
| | - Zachary D. Schultz
- University of Notre Dame, Department of Chemistry and Biochemistry, NotreDame, IN 46556
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8
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Weltin A, Kieninger J, Urban GA. Microfabricated, amperometric, enzyme-based biosensors for in vivo applications. Anal Bioanal Chem 2016; 408:4503-21. [PMID: 26935934 PMCID: PMC4909808 DOI: 10.1007/s00216-016-9420-4] [Citation(s) in RCA: 57] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2015] [Revised: 02/08/2016] [Accepted: 02/12/2016] [Indexed: 01/19/2023]
Abstract
Miniaturized electrochemical in vivo biosensors allow the measurement of fast extracellular dynamics of neurotransmitter and energy metabolism directly in the tissue. Enzyme-based amperometric biosensing is characterized by high specificity and precision as well as high spatial and temporal resolution. Aside from glucose monitoring, many systems have been introduced mainly for application in the central nervous system in animal models. We compare the microsensor principle with other methods applied in biomedical research to show advantages and drawbacks. Electrochemical sensor systems are easily miniaturized and fabricated by microtechnology processes. We review different microfabrication approaches for in vivo sensor platforms, ranging from simple modified wires and fibres to fully microfabricated systems on silicon, ceramic or polymer substrates. The various immobilization methods for the enzyme such as chemical cross-linking and entrapment in polymer membranes are discussed. The resulting sensor performance is compared in detail. We also examine different concepts to reject interfering substances by additional membranes, aspects of instrumentation and biocompatibility. Practical considerations are elaborated, and conclusions for future developments are presented. Graphical Abstract ᅟ.
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Affiliation(s)
- Andreas Weltin
- Laboratory for Sensors, Department of Microsystems Engineering – IMTEK, University of Freiburg, Georges-Köhler-Allee 103, 79110 Freiburg, Germany
| | - Jochen Kieninger
- Laboratory for Sensors, Department of Microsystems Engineering – IMTEK, University of Freiburg, Georges-Köhler-Allee 103, 79110 Freiburg, Germany
| | - Gerald A. Urban
- Laboratory for Sensors, Department of Microsystems Engineering – IMTEK, University of Freiburg, Georges-Köhler-Allee 103, 79110 Freiburg, Germany
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9
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Silicon/SU8 multi-electrode micro-needle for in vivo neurochemical monitoring. Biosens Bioelectron 2015; 72:148-55. [DOI: 10.1016/j.bios.2015.05.004] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2015] [Accepted: 05/05/2015] [Indexed: 11/23/2022]
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10
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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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11
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Samseya J, Srinivasan R, Chang YT, Tsao CW, Vasantha V. Fabrication and characterisation of high performance polypyrrole modified microarray sensor for ascorbic acid determination. Anal Chim Acta 2013; 793:11-8. [DOI: 10.1016/j.aca.2013.06.049] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2013] [Revised: 06/24/2013] [Accepted: 06/28/2013] [Indexed: 11/16/2022]
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12
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A New Trend on Biosensor for Neurotransmitter Choline/Acetylcholine—an Overview. Appl Biochem Biotechnol 2013; 169:1927-39. [DOI: 10.1007/s12010-013-0099-0] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2012] [Accepted: 01/10/2013] [Indexed: 11/27/2022]
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13
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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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14
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Palivan CG, Fischer-Onaca O, Delcea M, Itel F, Meier W. Protein–polymer nanoreactors for medical applications. Chem Soc Rev 2012; 41:2800-23. [DOI: 10.1039/c1cs15240h] [Citation(s) in RCA: 141] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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15
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Rothwell SA, O'Neill RD. Effects of applied potential on the mass of non-conducting poly(ortho-phenylenediamine) electro-deposited on EQCM electrodes: comparison with biosensor selectivity parameters. Phys Chem Chem Phys 2011; 13:5413-21. [PMID: 21359356 DOI: 10.1039/c0cp02341h] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
An electrochemical quartz-crystal microbalance (EQCM) was used to determine the mass of poly-(o-phenylenediamine) (PoPD) layers electro-deposited at different applied potentials in neutral buffered monomer solution, conditions that produce the insulating form of the polymer used as a permselective membrane in biosensor applications. There was a systematic increase in the total, steady state PoPD mass deposited for fixed applied potentials from 0.05 to 0.6 V vs. SCE, followed by a plateau up to 0.8 V. Comparison of PoPD mass and permselectivity parameters indicates that the ability of the passivating form of PoPD to block interference species in biosensor applications is not related in a simple way to the mass of material deposited on the surface. Instead, effects of the applied electropolymerisation potential in driving the electro-oxidation of oPD dimers and oligomers formed during the electro-deposition process are likely to have a more direct impact on the selectivity characteristics of the PoPD layer. The results highlight the usefulness of apparent permeabilities, especially of ascorbic acid, in revealing differences between PoPD layers electro-deposited under different conditions.
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Affiliation(s)
- Sharon A Rothwell
- UCD School of Chemistry and Chemical Biology, University College Dublin, Belfield, Dublin 4, Ireland
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16
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Hascup ER, Hascup KN, Stephens M, Pomerleau F, Huettl P, Gratton A, Gerhardt GA. Rapid microelectrode measurements and the origin and regulation of extracellular glutamate in rat prefrontal cortex. J Neurochem 2010; 115:1608-20. [PMID: 20969570 DOI: 10.1111/j.1471-4159.2010.07066.x] [Citation(s) in RCA: 90] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Glutamate in the prefrontal cortex (PFC) plays a significant role in several mental illnesses, including schizophrenia, addiction and anxiety. Previous studies on PFC glutamate-mediated function have used techniques that raise questions on the neuronal versus astrocytic origin of glutamate. The present studies used enzyme-based microelectrode arrays to monitor second-by-second resting glutamate levels in the PFC of awake rats. Locally applied drugs were employed in an attempt to discriminate between the neuronal or glial components of the resting glutamate signal. Local application of tetrodotoxin (sodium channel blocker), produced a significant (∼ 40%) decline in resting glutamate levels. In addition significant reductions in extracellular glutamate were seen with locally applied ω-conotoxin (MVIIC; ∼ 50%; calcium channel blocker), and the mGluR(2/3) agonist, LY379268 (∼ 20%), and a significant increase with the mGluR(2/3) antagonist LY341495 (∼ 40%), effects all consistent with a large neuronal contribution to the resting glutamate levels. Local administration of D,L-threo-β-benzyloxyaspartate (glutamate transporter inhibitor) produced an ∼ 120% increase in extracellular glutamate levels, supporting that excitatory amino acid transporters, which are largely located on glia, modulate clearance of extracellular glutamate. Interestingly, local application of (S)-4-carboxyphenylglycine (cystine/glutamate antiporter inhibitor), produced small, non-significant bi-phasic changes in extracellular glutamate versus vehicle control. Finally, pre-administration of tetrodotoxin completely blocked the glutamate response to tail pinch stress. Taken together, these results support that PFC resting glutamate levels in rats as measured by the microelectrode array technology are at least 40-50% derived from neurons. Furthermore, these data support that the impulse flow-dependent glutamate release from a physiologically -evoked event is entirely neuronally derived.
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Affiliation(s)
- Erin R Hascup
- Department of Psychiatry, Douglas Mental Health University Institute, McGill University, Montreal, Canada.
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17
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Enzyme immobilization strategies and electropolymerization conditions to control sensitivity and selectivity parameters of a polymer-enzyme composite glucose biosensor. SENSORS 2010; 10:6439-62. [PMID: 22163559 PMCID: PMC3231131 DOI: 10.3390/s100706439] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/13/2010] [Revised: 05/21/2010] [Accepted: 06/13/2010] [Indexed: 11/17/2022]
Abstract
In an ongoing programme to develop characterization strategies relevant to biosensors for in-vivo monitoring, glucose biosensors were fabricated by immobilizing the enzyme glucose oxidase (GOx) on 125 μm diameter Pt cylinder wire electrodes (Pt(C)), using three different methods: before, after or during the amperometric electrosynthesis of poly(ortho-phenylenediamine), PoPD, which also served as a permselective membrane. These electrodes were calibrated with H(2)O(2) (the biosensor enzyme signal molecule), glucose, and the archetypal interference compound ascorbic acid (AA) to determine the relevant polymer permeabilities and the apparent Michaelis-Menten parameters for glucose. A number of selectivity parameters were used to identify the most successful design in terms of the balance between substrate sensitivity and interference blocking. For biosensors electrosynthesized in neutral buffer under the present conditions, entrapment of the GOx within the PoPD layer produced the design (Pt(C)/PoPD-GOx) with the highest linear sensitivity to glucose (5.0 ± 0.4 μA cm(-2) mM(-1)), good linear range (K(M) = 16 ± 2 mM) and response time (< 2 s), and the greatest AA blocking (99.8% for 1 mM AA). Further optimization showed that fabrication of Pt(C)/PoPD-GOx in the absence of added background electrolyte (i.e., electropolymerization in unbuffered enzyme-monomer solution) enhanced glucose selectivity 3-fold for this one-pot fabrication protocol which provided AA-rejection levels at least equal to recent multi-step polymer bilayer biosensor designs. Interestingly, the presence of enzyme protein in the polymer layer had opposite effects on permselectivity for low and high concentrations of AA, emphasizing the value of studying the concentration dependence of interference effects which is rarely reported in the literature.
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Rothwell SA, Kinsella ME, Zain ZM, Serra PA, Rocchitta G, Lowry JP, O'Neill RD. Contributions by a novel edge effect to the permselectivity of an electrosynthesized polymer for microbiosensor applications. Anal Chem 2009; 81:3911-8. [PMID: 19371060 DOI: 10.1021/ac900162c] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Pt electrodes of different sizes (2 x 10(-5)-2 x 10(-2) cm(2)) and geometries (disks and cylinders) were coated with the ultrathin non-conducting form of poly(o-phenylenediamine), PPD, using amperometric electrosynthesis. Analysis of the ascorbic acid (AA) and H(2)O(2) apparent permeabilities for these Pt/PPD sensors revealed that the PPD deposited near the electrode insulation (Teflon or glass edge) was not as effective as the bulk surface PPD for blocking AA access to the Pt substrate. This discovery impacts on the design of implantable biosensors where electrodeposited polymers, such as PPD, are commonly used as the permselective barrier to block electroactive interference by reducing agents present in the target medium. The undesirable "edge effect" was particularly marked for small disk electrodes which have a high edge density (ratio of PPD-insulation edge length to electrode area), but was essentially absent for cylinder electrodes with a length of >0.2 mm. Sample biosensors, with a configuration based on these findings (25 microm diameter Pt fiber cylinders) and designed for brain neurotransmitter L-glutamate, behaved well in vitro in terms of Glu sensitivity and AA blocking.
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Affiliation(s)
- Sharon A Rothwell
- UCD School of Chemistry and Chemical Biology, University College Dublin, Belfield, Dublin 4, Ireland
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Abstract
Carbon-fiber microelectrodes (CFMEs) have been a useful tool for measuring rapid changes in neurotransmitters because of their small size, sensitivity, and good electrochemical properties. In this article, we highlight recent advances using CFMEs for measuring neurotransmitters in vivo. Dopamine has been a primary neurotransmitter of interest but direct electrochemical detection of other neurochemicals including nitric oxide and adenosine has also been investigated. Surface treatments have been studied to enhance electrode sensitivity, such as covalent modification or the addition of a layer of carbon nanotubes. Enzyme-modified microelectrodes that detect non-electroactive compounds further extend the usefulness of CFMEs beyond the traditional monoamines. CFMEs continue to be used in vivo to understand basic neurobiological mechanisms and the actions of pharmacological agents, including drugs of abuse. Advances in sensitivity and instrumentation now allow CFMEs to be used for measurements of natural dopamine release that occur during behavioral experiments. A new technique combining electrochemistry with electrophysiology at a single microelectrode facilitates a better understanding of neurotransmitter concentrations and their effects on cell firing. Future research in this field will likely concentrate on fabricating smaller electrodes and electrode arrays, as well as expanding the use of CFMEs in neuroscience beyond dopamine.
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Affiliation(s)
- Megan L Huffman
- Department of Chemistry, University of Virginia, P.O. Box 400319, Charlottesville, VA 22904, USA
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21
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Parikh V, Sarter M. Cholinergic mediation of attention: contributions of phasic and tonic increases in prefrontal cholinergic activity. Ann N Y Acad Sci 2008; 1129:225-35. [PMID: 18591483 DOI: 10.1196/annals.1417.021] [Citation(s) in RCA: 138] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Contrary to the classic description of acetylcholine (ACh) as a slowly acting neuromodulator that influences arousal states, results from experiments that employed enzyme-selective microelectrodes for the real-time monitoring of ACh release in the cortex of attentional task-performing rats indicate that cholinergic signals manifesting on multiple timescales (seconds, tens of seconds, and minutes) support, and are necessary for, the mediation of defined cognitive operations. Specifically, in the prefrontal cortex, second-based cholinergic signals support the detection of behaviorally significant cues. In contrast to these prefrontal cholinergic transients, performance-associated cholinergic activity that manifested at lower temporal resolution also was observed elsewhere in the cortex. Although tonic cholinergic signal levels were correlated with the amplitudes of cue-evoked cholinergic transients, and the latter with response latencies, the interrelationships and interactions between the multiple cholinergic signaling modes remains unclear. Hypotheses concerning the afferent circuitry contributing to the regulation of second- versus minute-based cholinergic signals are discussed. The discovery of cholinergic transients and their crucial role in cue detection and attentional performance form the basis for new hypotheses about the nature of cholinergic dysfunction in cognitive disorders and offer new targets for the development of treatments for the cognitive symptoms of neuropsychiatric and neurodegenerative disorders.
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Affiliation(s)
- Vinay Parikh
- Department of Psychology and Neuroscience Program, University of Michigan, Ann Arbor, MI 48109-1043, USA
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Robinson DL, Hermans A, Seipel AT, Wightman RM. Monitoring rapid chemical communication in the brain. Chem Rev 2008; 108:2554-84. [PMID: 18576692 PMCID: PMC3110685 DOI: 10.1021/cr068081q] [Citation(s) in RCA: 454] [Impact Index Per Article: 28.4] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Affiliation(s)
- Donita L Robinson
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-3290, USA
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Rothwell SA, Killoran SJ, Neville EM, Crotty AM, O’Neill RD. Poly(o-phenylenediamine) electrosynthesized in the absence of added background electrolyte provides a new permselectivity benchmark for biosensor applications. Electrochem commun 2008. [DOI: 10.1016/j.elecom.2008.05.018] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
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Electrochemical Dopamine Detection: Comparing Gold and Carbon Fiber Microelectrodes using Background Subtracted Fast Scan Cyclic Voltammetry. J Electroanal Chem (Lausanne) 2008; 614:113-120. [PMID: 19319208 DOI: 10.1016/j.jelechem.2007.11.007] [Citation(s) in RCA: 102] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Electrochemical detection is becoming increasingly important for the detection of biological species. Most current biological research with electrochemical detection is done with carbon fiber electrodes due to their many beneficial properties. The ability to build electrochemical sensor from noble metals instead of carbon fibers may be beneficial in developing inexpensive multiplexed electrochemical detection schemes. To advance understanding and to test the feasibility of using noble metal electrochemical sensors the detection of dopamine, a biologically important small molecule was studied here. Specifically, dopamine detection on gold microelectrodes was characterized and compared to P-55 carbon fiber microelectrodes of the same geometry, using background subtracted fast scan cyclic voltammetry. While not as sensitive to dopamine as carbon fibers, it was observed that gold microelectrodes have six times the saturation coverage per area and 40 times the linear working range. Selectivity to dopamine, in comparison to several other neurotransmitters and their derivatives, is also quantitatively described.
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Hascup KN, Hascup ER, Pomerleau F, Huettl P, Gerhardt GA. Second-by-second measures of L-glutamate in the prefrontal cortex and striatum of freely moving mice. J Pharmacol Exp Ther 2008; 324:725-31. [PMID: 18024788 PMCID: PMC3404456 DOI: 10.1124/jpet.107.131698] [Citation(s) in RCA: 82] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
l-Glutamate (Glu) is the main excitatory neurotransmitter in the mammalian central nervous system, and it is involved in most aspects of normal brain function, including cognition, memory and learning, plasticity, and motor movement. Although microdialysis techniques have been used to study Glu, the slow temporal resolution of the technique may be inadequate to properly examine tonic and phasic Glu. Thus, our laboratory has developed an enzyme-based microelectrode array (MEA) with fast response time and low detection limits for Glu. We have modified the MEA design to allow for reliable measures in the brain of awake, freely moving mice. In this study, we chronically implanted the MEA in prefrontal cortex (PFC) or striatum (Str) of awake, freely moving C57BL/6 mice. We successfully measured Glu levels 7 days postimplantation without loss of MEA sensitivity. In addition, we determined resting (tonic) Glu levels to be 3.3 microM in the PFC and 5.0 microM in the Str. Resting Glu levels were subjected to pharmacological manipulation with tetrodotoxin (TTX) and dl-threo-beta-hydroxyaspartate (THA). TTX significantly (p < 0.05) decreased resting Glu by 20%, whereas THA significantly (p < 0.05) increased resting Glu by 60%. Taken together, our data show that chronic recordings of tonic and phasic clearance of exogenously applied Glu can be carried out in awake mice for at least 7 days in vivo, allowing for longer term studies of Glu regulation.
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Affiliation(s)
- K N Hascup
- Department of Anatomy and Neurobiology, 306 Whitney-Hendrickson Facility, 800 Rose St., Lexington, KY 40536-0098, USA
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26
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Prefrontal acetylcholine release controls cue detection on multiple timescales. Neuron 2008; 56:141-54. [PMID: 17920021 DOI: 10.1016/j.neuron.2007.08.025] [Citation(s) in RCA: 460] [Impact Index Per Article: 28.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2007] [Revised: 08/10/2007] [Accepted: 08/29/2007] [Indexed: 10/22/2022]
Abstract
Cholinergic neurons originating from the basal forebrain innervate the entire cortical mantle. Choline-sensitive microelectrodes were used to measure the synaptic release of cortical acetylcholine (ACh) at a subsecond resolution in rats performing a task involving the detection of cues. Cues that were detected, defined behaviorally, evoked transient increases in cholinergic activity (at the scale of seconds) in the medial prefrontal cortex (mPFC), but not in a nonassociational control region (motor cortex). In trials involving missed cues, cholinergic transients were not observed. Cholinergic deafferentation of the mPFC, but not motor cortex, impaired cue detection. Furthermore, decreases and increases in precue cholinergic activity predicted subsequent cue detection or misses, respectively. Finally, cue-evoked cholinergic transients were superimposed over slower (at the timescale of minutes) changes in cholinergic activity. Cortical cholinergic neurotransmission is regulated on multiple timescales to mediate the detection of behaviorally significant cues and to support cognitive performance.
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Designing sensitive and selective polymer/enzyme composite biosensors for brain monitoring in vivo. Trends Analyt Chem 2008. [DOI: 10.1016/j.trac.2007.11.008] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
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Frey O, van der Wal P, de Rooij N, Koudelka-Hep M. Development and Characterization of Choline and L-Glutamate Biosensor Integrated on Silicon Microprobes for In-Vivo Monitoring. ACTA ACUST UNITED AC 2007; 2007:6040-3. [DOI: 10.1109/iembs.2007.4353725] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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29
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McMahon CP, Rocchitta G, Serra PA, Kirwan SM, Lowry JP, O'Neill RD. Control of the oxygen dependence of an implantable polymer/enzyme composite biosensor for glutamate. Anal Chem 2007; 78:2352-9. [PMID: 16579619 DOI: 10.1021/ac0518194] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Biosensors for glutamate (Glu) were fabricated from Teflon-coated Pt wire (cylinders and disks), modified with the enzyme glutamate oxidase (GluOx) and electrosynthesized polymer PPD, poly(o-phenylenediamine). The polymer/enzyme layer was deposited in two configurations: enzyme before polymer (GluOx/PPD) and enzyme after polymer (PPD/GluOx). These four biosensor designs were characterized in terms of response time, limit of detection, Michaelis-Menten parameters for Glu (J max and K(M)(Glu)), sensitivity to Glu in the linear response region, and dependence on oxygen concentration, K(M)(O2). Analysis showed that the two polymer/enzyme configurations behaved similarly on both cylinders and disks. Although the two geometries showed different behaviors, these differences could be explained in terms of higher enzyme loading density on the disks; in many analyses, the four designs behaved like a single population with a range of GluOx loading. Enzyme loading was the key to controlling the K(M)(O2) values of these first generation biosensors. The counterintuitive, and beneficial, behavior that biosensors with higher GluOx loading displayed a lower oxygen dependence was explained in terms of the effects of enzyme loading on the affinity of GluOx for its anionic substrate. Some differences between the properties of surface immobilized GluOx and glucose oxidase are highlighted.
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Affiliation(s)
- Colm P McMahon
- UCD School of Chemistry and Chemical Biology, University College Dublin, Belfield, Dublin 4, Ireland
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Day BK, Pomerleau F, Burmeister JJ, Huettl P, Gerhardt GA. Microelectrode array studies of basal and potassium-evoked release of L-glutamate in the anesthetized rat brain. J Neurochem 2006; 96:1626-35. [PMID: 16441510 DOI: 10.1111/j.1471-4159.2006.03673.x] [Citation(s) in RCA: 144] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
L-glutamate (Glu) is the predominant excitatory neurotransmitter in the mammalian central nervous system. It plays major roles in normal neurophysiology and many brain disorders by binding to membrane-bound Glu receptors. To overcome the spatial and temporal limitations encountered in previous in vivo extracellular Glu studies, we employed enzyme-coated microelectrode arrays to measure both basal and potassium-evoked release of Glu in the anesthetized rat brain. We also addressed the question of signal identity, which is the predominant criticism of these recording technologies. In vivo self-referencing recordings demonstrated that our Glu signals were both enzyme- and voltage-dependent, supporting the identity of L-glutamate. In addition, basal Glu was actively regulated, tetrodotoxin (TTX)-dependent, and measured in the low micromolar range (approximately 2 microm) using multiple self-referencing subtraction approaches for identification of Glu. Moreover, potassium-evoked Glu release exhibited fast kinetics that were concentration-dependent and reproducible. These data support the hypothesis that Glu release is highly regulated, requiring detection technologies that must be very close to the synapse and measure on a second-by-second basis to best characterize the dynamics of the Glu system.
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Affiliation(s)
- B K Day
- Center For Sensor Technology, Morris K. Udall Parkinson's Disease Research Center of Excellence, Department of Anatomy and Neurobiology, University of Kentucky, Lexington, Kentucky 40536-0098, USA
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McMahon CP, Rocchitta G, Serra PA, Kirwan SM, Lowry JP, O'Neill RD. The efficiency of immobilised glutamate oxidase decreases with surface enzyme loading: an electrostatic effect, and reversal by a polycation significantly enhances biosensor sensitivity. Analyst 2006; 131:68-72. [PMID: 16365665 DOI: 10.1039/b511643k] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The apparent Michaelis constant, K(M), for glutamate oxidase (GluOx) immobilised on Pt electrodes increased systematically with enzyme loading. The effect was due, at least in part, to electrostatic repulsion between neighbouring oxidase molecules and the anionic substrate, glutamate (Glu). This understanding has allowed us to increase the Glu sensitivity of GluOx-based amperometric biosensors in the linear response region (100+/-11 nA cm(-2)microM(-1) at pH 7.4; SD, n=23) by incorporating a polycation (polyethyleneimine, PEI) to counterbalance the polyanionic protein. Differences in the behaviour of glucose biosensors of a similar configuration highlight a limitation of using glucose oxidase as a model enzyme in biosensor design.
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Affiliation(s)
- Colm P McMahon
- UCD School of Chemistry and Chemical Biology, University College Dublin, Belfield, Dublin 4, Ireland
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32
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Mitala J, Michael A. Improving the performance of electrochemical microsensors based on enzymes entrapped in a redox hydrogel. Anal Chim Acta 2006. [DOI: 10.1016/j.aca.2005.09.053] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Dale N, Hatz S, Tian F, Llaudet E. Listening to the brain: microelectrode biosensors for neurochemicals. Trends Biotechnol 2005; 23:420-8. [PMID: 15950302 DOI: 10.1016/j.tibtech.2005.05.010] [Citation(s) in RCA: 91] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2005] [Revised: 04/19/2005] [Accepted: 05/24/2005] [Indexed: 10/25/2022]
Abstract
Chemical signalling underlies every function of the nervous system, from those of which we are unaware, for example, control of the heart, to higher cognitive functions, such as emotions, learning and memory. Neurotransmitters and neuromodulators mediate communication between neurons and between neurons and non-neural cells such as glia and muscle. In the past, the means for studying the production and release of these signalling agents directly has been limited in its temporal and spatial resolution relative to the dynamics of chemical signalling and the structures of interest in the brain. Now microelectrode biosensors are becoming available that give unprecedented spatial and temporal resolution, enabling, for the first time, direct measurement in real time of the chemical conversations between cells in the nervous system.
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Affiliation(s)
- Nicholas Dale
- Warwick Biosensors Group, Department of Biological Sciences, The University of Warwick, Coventry, CV4 7AL, UK.
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Abstract
Cholinergic projections to the cortex and hippocampus mediate fundamental cognitive processes. The capacity of the high-affinity choline uptake transporter (CHT) to import choline from the extracellular space to presynaptic terminals is essential for normal acetylcholine synthesis and therefore cholinergic transmission. The CHT is highly regulated, and the cellular mechanisms that modulate its capacity show considerable plasticity. Recent evidence links changes in CHT capacity with the ability to perform tasks that tax attentional processes and capacities. Abnormal regulation of CHT capacity might contribute to the cognitive impairments that are associated with neurodegenerative and neuropsychiatric disorders. Therefore, the CHT might represent a productive target for the development of new pharmacological treatments for these conditions.
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Affiliation(s)
- Martin Sarter
- Department of Psychology, University of Michigan, 4032 East Hall, 525 East University Avenue, Ann Arbor, Michigan 48109, USA.
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McMahon CP, O'Neill RD. Polymer−Enzyme Composite Biosensor with High Glutamate Sensitivity and Low Oxygen Dependence. Anal Chem 2005; 77:1196-9. [PMID: 15859007 DOI: 10.1021/ac048686r] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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