1
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Zhou H, Zhong Z, Wei S, Yu P, Jiang J, Mao L. Transmembrane Graphene as an Electron Tunnel to Regulate the Intracellular Redox State. NANO LETTERS 2024; 24:10396-10401. [PMID: 39116269 DOI: 10.1021/acs.nanolett.4c03255] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/10/2024]
Abstract
Cellular redox homeostasis is essential for maintaining cellular activities, such as DNA synthesis and gene expression. Inspired by this, new therapeutic interventions have been rapidly developed to modulate the intracellular redox state using artificial transmembrane electron transport. However, current approaches that rely on external electric field polarization can disrupt cellular functions, limiting their in vivo application. Therefore, it is crucial to develop novel electric-field-free modulation methods. In this work, we for the first time found that graphene could spontaneously insert into living cell membranes and serve as an electron tunnel to regulate intracellular reactive oxygen species and NADH based on the spontaneous bipolar electrochemical reaction mechanism. This work provides a wireless and electric-field-free approach to regulating cellular redox states directly and offers possibilities for biological applications such as cell process intervention and treatment for neurodegenerative diseases.
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Affiliation(s)
- Haoyang Zhou
- Beijing National Laboratory for Molecular Sciences, Key Laboratory of Analytical Chemistry for Living Biosystems, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Zhixuan Zhong
- Beijing National Laboratory for Molecular Sciences, State Key Laboratory of Polymer Physics and Chemistry, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Shiyi Wei
- Beijing National Laboratory for Molecular Sciences, Key Laboratory of Analytical Chemistry for Living Biosystems, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Ping Yu
- Beijing National Laboratory for Molecular Sciences, Key Laboratory of Analytical Chemistry for Living Biosystems, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Jian Jiang
- Beijing National Laboratory for Molecular Sciences, State Key Laboratory of Polymer Physics and Chemistry, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Lanqun Mao
- College of Chemistry, Beijing Normal University, Beijing 100875, China
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2
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Ni J, Wei H, Ji W, Xue Y, Zhu F, Wang C, Jiang Y, Mao L. Aptamer-Based Potentiometric Sensor Enables Highly Selective and Neurocompatible Neurochemical Sensing in Rat Brain. ACS Sens 2024; 9:2447-2454. [PMID: 38659329 DOI: 10.1021/acssensors.4c00119] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/26/2024]
Abstract
Selective and nondisruptive in vivo neurochemical monitoring within the central nervous system has long been a challenging endeavor. We introduce a new sensing approach that integrates neurocompatible galvanic redox potentiometry (GRP) with customizable phosphorothioate aptamers to specifically probe dopamine (DA) dynamics in live rat brains. The aptamer-functionalized GRP (aptGRP) sensor demonstrates nanomolar sensitivity and over a 10-fold selectivity for DA, even amidst physiological levels of major interfering species. Notably, conventional sensors without the aptamer modification exhibit negligible reactivity to DA concentrations exceeding 20 μM. Critically, the aptGRP sensor operates without altering neuronal activity, thereby permitting real-time, concurrent recordings of both DA flux and electrical signaling in vivo. This breakthrough establishes aptGRP as a viable and promising framework for the development of high-fidelity sensors, offering novel insights into neurotransmission dynamics in a live setting.
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Affiliation(s)
- Jiping Ni
- College of Chemistry, Beijing Normal University, Beijing 100875, P.R. China
- State Key Laboratory of Heavy Oil Processing, College of New Energy and Materials, China University of Petroleum (Beijing), Beijing 102249, P.R. China
| | - Huan Wei
- College of Chemistry, Beijing Normal University, Beijing 100875, P.R. China
| | - Wenliang Ji
- College of Chemistry, Beijing Normal University, Beijing 100875, P.R. China
| | - Yifei Xue
- College of Chemistry, Beijing Normal University, Beijing 100875, P.R. China
| | - Fenghui Zhu
- College of Chemistry, Beijing Normal University, Beijing 100875, P.R. China
| | - Chunxia Wang
- State Key Laboratory of Heavy Oil Processing, College of New Energy and Materials, China University of Petroleum (Beijing), Beijing 102249, P.R. China
| | - Ying Jiang
- College of Chemistry, Beijing Normal University, Beijing 100875, P.R. China
| | - Lanqun Mao
- College of Chemistry, Beijing Normal University, Beijing 100875, P.R. China
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3
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Lu J, Zhuang X, Wei H, Liu R, Ji W, Yu P, Ma W, Mao L. Enzymatic Galvanic Redox Potentiometry for In Vivo Biosensing. Anal Chem 2024; 96:3672-3678. [PMID: 38361229 DOI: 10.1021/acs.analchem.4c00185] [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: 02/17/2024]
Abstract
Redox potentiometry has emerged as a new platform for in vivo sensing, with improved neuronal compatibility and strong tolerance against sensitivity variation caused by protein fouling. Although enzymes show great possibilities in the fabrication of selective redox potentiometry, the fabrication of an enzyme electrode to output open-circuit voltage (EOC) with fast response remains challenging. Herein, we report a concept of novel enzymatic galvanic redox potentiometry (GRP) with improved time response coupling the merits of the high selectivity of enzyme electrodes with the excellent biocompatibility and reliability of GRP sensors. With a glucose biosensor as an illustration, we use flavin adenine dinucleotide-dependent glucose dehydrogenase as the recognition element and carbon black as the potential relay station to improve the response time. We find that the enzymatic GRP biosensor rapidly responds to glucose with a good linear relationship between EOC and the logarithm of glucose concentration within a range from 100 μM to 2.65 mM. The GRP biosensor shows high selectivity over O2 and coexisting neurochemicals, good reversibility, and sensitivity and can in vivo monitor glucose dynamics in rat brain. We believe that this study will pave a new platform for the in vivo potentiometric biosensing of chemical events with high reliability.
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Affiliation(s)
- Jiaojiao Lu
- College of Chemistry, Beijing Normal University, Xinjiekouwai Street 19, Beijing 100875, China
- College of Chemistry and Chemical Engineering, Yantai University, Yantai 264005, China
| | - Xuming Zhuang
- College of Chemistry and Chemical Engineering, Yantai University, Yantai 264005, China
| | - Huan Wei
- College of Chemistry, Beijing Normal University, Xinjiekouwai Street 19, Beijing 100875, China
| | - Ran Liu
- College of Chemistry, Beijing Normal University, Xinjiekouwai Street 19, Beijing 100875, China
| | - Wenliang Ji
- College of Chemistry, Beijing Normal University, Xinjiekouwai Street 19, Beijing 100875, China
| | - Ping Yu
- Beijing National Laboratory for Molecular Sciences, Key Laboratory of Analytical Chemistry for Living Biosystems, Institute of Chemistry, Chinese Academy of Sciences (CAS), Beijing 100190, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Wenjie Ma
- Beijing National Laboratory for Molecular Sciences, Key Laboratory of Analytical Chemistry for Living Biosystems, Institute of Chemistry, Chinese Academy of Sciences (CAS), Beijing 100190, China
| | - Lanqun Mao
- College of Chemistry, Beijing Normal University, Xinjiekouwai Street 19, Beijing 100875, China
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4
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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: 40] [Impact Index Per Article: 20.0] [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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5
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Yu P, Wei H, Zhong P, Xue Y, Wu F, Liu Y, Fei J, Mao L. Single‐Carbon‐Fiber‐Powered Microsensor for In Vivo Neurochemical Sensing with High Neuronal Compatibility. Angew Chem Int Ed Engl 2020. [DOI: 10.1002/ange.202010195] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
- Ping Yu
- Beijing National Laboratory for Molecular Science Key Laboratory of Analytical Chemistry for Living Biosystems Institute of Chemistry Chinese Academy of Sciences (CAS) Beijing 100190 China
- University of Chinese Academy of Sciences Beijing 100049 China
| | - Huan Wei
- Beijing National Laboratory for Molecular Science Key Laboratory of Analytical Chemistry for Living Biosystems Institute of Chemistry Chinese Academy of Sciences (CAS) Beijing 100190 China
- University of Chinese Academy of Sciences Beijing 100049 China
| | - Peipei Zhong
- Key Laboratory of Environmentally Friendly Chemistry and Applications of the Ministry of Education College of Chemistry Xiangtan University Xiangtan Hunan 411105 China
| | - Yifei Xue
- Beijing National Laboratory for Molecular Science Key Laboratory of Analytical Chemistry for Living Biosystems Institute of Chemistry Chinese Academy of Sciences (CAS) Beijing 100190 China
- University of Chinese Academy of Sciences Beijing 100049 China
| | - Fei Wu
- Beijing National Laboratory for Molecular Science Key Laboratory of Analytical Chemistry for Living Biosystems Institute of Chemistry Chinese Academy of Sciences (CAS) Beijing 100190 China
- University of Chinese Academy of Sciences Beijing 100049 China
| | - Yang Liu
- Beijing National Laboratory for Molecular Science Key Laboratory of Analytical Chemistry for Living Biosystems Institute of Chemistry Chinese Academy of Sciences (CAS) Beijing 100190 China
| | - Junjie Fei
- Key Laboratory of Environmentally Friendly Chemistry and Applications of the Ministry of Education College of Chemistry Xiangtan University Xiangtan Hunan 411105 China
| | - Lanqun Mao
- Beijing National Laboratory for Molecular Science Key Laboratory of Analytical Chemistry for Living Biosystems Institute of Chemistry Chinese Academy of Sciences (CAS) Beijing 100190 China
- University of Chinese Academy of Sciences Beijing 100049 China
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6
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Yu P, Wei H, Zhong P, Xue Y, Wu F, Liu Y, Fei J, Mao L. Single‐Carbon‐Fiber‐Powered Microsensor for In Vivo Neurochemical Sensing with High Neuronal Compatibility. Angew Chem Int Ed Engl 2020; 59:22652-22658. [DOI: 10.1002/anie.202010195] [Citation(s) in RCA: 44] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2020] [Indexed: 02/06/2023]
Affiliation(s)
- Ping Yu
- Beijing National Laboratory for Molecular Science Key Laboratory of Analytical Chemistry for Living Biosystems Institute of Chemistry Chinese Academy of Sciences (CAS) Beijing 100190 China
- University of Chinese Academy of Sciences Beijing 100049 China
| | - Huan Wei
- Beijing National Laboratory for Molecular Science Key Laboratory of Analytical Chemistry for Living Biosystems Institute of Chemistry Chinese Academy of Sciences (CAS) Beijing 100190 China
- University of Chinese Academy of Sciences Beijing 100049 China
| | - Peipei Zhong
- Key Laboratory of Environmentally Friendly Chemistry and Applications of the Ministry of Education College of Chemistry Xiangtan University Xiangtan Hunan 411105 China
| | - Yifei Xue
- Beijing National Laboratory for Molecular Science Key Laboratory of Analytical Chemistry for Living Biosystems Institute of Chemistry Chinese Academy of Sciences (CAS) Beijing 100190 China
- University of Chinese Academy of Sciences Beijing 100049 China
| | - Fei Wu
- Beijing National Laboratory for Molecular Science Key Laboratory of Analytical Chemistry for Living Biosystems Institute of Chemistry Chinese Academy of Sciences (CAS) Beijing 100190 China
- University of Chinese Academy of Sciences Beijing 100049 China
| | - Yang Liu
- Beijing National Laboratory for Molecular Science Key Laboratory of Analytical Chemistry for Living Biosystems Institute of Chemistry Chinese Academy of Sciences (CAS) Beijing 100190 China
| | - Junjie Fei
- Key Laboratory of Environmentally Friendly Chemistry and Applications of the Ministry of Education College of Chemistry Xiangtan University Xiangtan Hunan 411105 China
| | - Lanqun Mao
- Beijing National Laboratory for Molecular Science Key Laboratory of Analytical Chemistry for Living Biosystems Institute of Chemistry Chinese Academy of Sciences (CAS) Beijing 100190 China
- University of Chinese Academy of Sciences Beijing 100049 China
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7
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Wei H, Li L, Jin J, Wu F, Yu P, Ma F, Mao L. Galvanic Redox Potentiometry Based Microelectrode Array for Synchronous Ascorbate and Single-Unit Recordings in Rat Brain. Anal Chem 2020; 92:10177-10182. [PMID: 32600032 DOI: 10.1021/acs.analchem.0c02225] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Neuronal communication relies on cooperation between the chemical and electrical patterns of neurons. Thus, techniques for illustrating the linkage of the neurochemical events and action potentials with high temporal and spatial resolution is imperative to gain a comprehensive understanding of the intricacies of brain function. Herein, we integrate galvanic redox potentiometry (GRP) and electrophysiological recording onto a 16-site Au microelectrode array (MEA), one of which is for indicating the ascorbate concentration while the others for single-unit activity assessment. The electrochemical probing site was modified with single-walled carbon nanotubes to promote electron-transfer kinetics of ascorbate at low overpotential so as to enlarge the driving force for the spontaneous ascorbate/O2 cell reaction. The resulting GRP-based MEA outputs open-circuit potential that is in a linear relationship with the logarithmic ascorbate concentration and exhibits high selectivity against a set of coexisting electroactive species. Furthermore, no reciprocal interference between the two recording systems is observed during concurrent GRP sensing of ascorbate and single-unit recording in a rat brain. In vivo feasibility of the GRP-based MEA is demonstrated by synchronous real-time measurement of ascorbate release and electrical activity from multiple neuronal populations during spreading depression. Our GRP-based MEA sensor creates new opportunities to realize high-throughput screening or mapping of neurochemical patterns in a larger dimension and correlate them to neuron functions across a spatial scale.
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Affiliation(s)
- Huan Wei
- Beijing National Laboratory for Molecular Sciences, 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
| | - Lijuan Li
- Department of Otorhinolaryngology, Peking University Third Hospital, Beijing 100083, China
| | - Jing Jin
- Beijing National Laboratory for Molecular Sciences, 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
- Beijing National Laboratory for Molecular Sciences, 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
- Beijing National Laboratory for Molecular Sciences, 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
| | - Furong Ma
- Department of Otorhinolaryngology, Peking University Third Hospital, Beijing 100083, China
| | - Lanqun Mao
- Beijing National Laboratory for Molecular Sciences, 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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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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10
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Wu F, Yu P, Mao L. Analytical and Quantitative in Vivo Monitoring of Brain Neurochemistry by Electrochemical and Imaging Approaches. ACS OMEGA 2018; 3:13267-13274. [PMID: 30411032 PMCID: PMC6217607 DOI: 10.1021/acsomega.8b02055] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/16/2018] [Accepted: 10/02/2018] [Indexed: 05/27/2023]
Abstract
Quantitative monitoring of brain neurochemistry is aimed at an accurate measurement of chemical basal levels and dynamics defining neuronal activities. Analytical tools must be endowed with high selectivity, sensitivity, and spatiotemporal resolution to tackle this task. On one hand, in vivo electroanalysis combined with miniature electrodes has evolved into a minimally invasive method for probing transient events during neural communication and metabolism. On the other hand, noninvasive imaging techniques have been widely adopted in visualizing the neural structure and processes within a population of neurons in two or three dimensions. This perspective will give a concise review of the inspiring frontiers at the interface of neurochemistry and electrochemistry (microvoltammetry, nanoamperometry, galvanic redox potentiometry and ion transport-based sensing) or imaging (super-resolution single nanotube tracking, deep multiphoton microscopy, and free animal imaging). Potential opportunities with these methods and their combinations for multimodal brain analysis will be discussed, intending to draw a brief picture for future neuroscience research.
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Affiliation(s)
- Fei Wu
- Beijing
National Laboratory for Molecular Sciences, Key Laboratory of Analytical
Chemistry for Living Biosystems, Institute of Chemistry, The Chinese Academy of Sciences (CAS), Beijing 100190, China
- University
of CAS, Beijing 100049, China
- CAS
Research/Education Center for Excellence in Molecule Science, Beijing 100190, China
| | - Ping Yu
- Beijing
National Laboratory for Molecular Sciences, Key Laboratory of Analytical
Chemistry for Living Biosystems, Institute of Chemistry, The Chinese Academy of Sciences (CAS), Beijing 100190, China
- University
of CAS, Beijing 100049, China
- CAS
Research/Education Center for Excellence in Molecule Science, Beijing 100190, China
| | - Lanqun Mao
- Beijing
National Laboratory for Molecular Sciences, Key Laboratory of Analytical
Chemistry for Living Biosystems, Institute of Chemistry, The Chinese Academy of Sciences (CAS), Beijing 100190, China
- University
of CAS, Beijing 100049, China
- CAS
Research/Education Center for Excellence in Molecule Science, Beijing 100190, China
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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: 1.9] [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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Cheng H, Xiao T, Wang D, Hao J, Yu P, Mao L. Simultaneous in vivo ascorbate and electrophysiological recordings in rat brain following ischemia/reperfusion. J Electroanal Chem (Lausanne) 2016. [DOI: 10.1016/j.jelechem.2016.10.024] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
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13
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Salim MIM, Supriyanto E, Haueisen J, Ariffin I, Ahmad AH, Rosidi B. Measurement of bioelectric and acoustic profile of breast tissue using hybrid magnetoacoustic method for cancer detection. Med Biol Eng Comput 2012; 51:459-66. [PMID: 23238828 DOI: 10.1007/s11517-012-1014-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2012] [Accepted: 12/03/2012] [Indexed: 10/27/2022]
Abstract
This paper proposes a novel hybrid magnetoacoustic measurement (HMM) system aiming at breast cancer detection. HMM combines ultrasound and magnetism for the simultaneous assessment of bioelectric and acoustic profiles of breast tissue. HMM is demonstrated on breast tissue samples, which are exposed to 9.8 MHz ultrasound wave with the presence of a 0.25 Tesla static magnetic field. The interaction between the ultrasound wave and the magnetic field in the breast tissue results in Lorentz Force that produces a magnetoacoustic voltage output, proportional to breast tissue conductivity. Simultaneously, the ultrasound wave is sensed back by the ultrasound receiver for tissue acoustic evaluation. Experiments are performed on gel phantoms and real breast tissue samples harvested from laboratory mice. Ultrasound wave characterization results show that normal breast tissue experiences higher attenuation compared with cancerous tissue. The mean magnetoacoustic voltage results for normal tissue are lower than that for the cancerous tissue group. In conclusion, the combination of acoustic and bioelectric measurements is a promising approach for breast cancer diagnosis.
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Affiliation(s)
- M I Mohamad Salim
- Department of Clinical Sciences, Faculty of Biosciences and Medical Engineering, Universiti Teknologi Malaysia, Johor Bahru, Malaysia.
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Abstract
Given the increasing demand for practical and low-cost analytical techniques, biosensors have attracted attention for use in the quality analysis of drugs, medicines, and other analytes of interest in the pharmaceutical area. Biosensors allow quantification not only of the active component in pharmaceutical formulations, but also the analysis of degradation products and metabolites in biological fluids. Thus, this article presents a brief review of biosensor use in pharmaceutical analysis, focusing on enzymatic electrochemical sensors.
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15
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SK channel blocker apamin attenuates the effect of SSRI fluoxetine upon cell firing in dorsal raphe nucleus: A concomitant electrophysiological and electrochemical in vivo study reveals implications for modulating extracellular 5-HT. Brain Res 2010; 1334:1-11. [DOI: 10.1016/j.brainres.2010.03.081] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2009] [Revised: 03/22/2010] [Accepted: 03/23/2010] [Indexed: 11/23/2022]
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16
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Crespi F. Apamin increases 5-HT cell firing in raphe dorsalis and extracellular 5-HT levels in amygdala: A concomitant in vivo study in anesthetized rats. Brain Res 2009; 1281:35-46. [DOI: 10.1016/j.brainres.2009.05.021] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2009] [Revised: 05/07/2009] [Accepted: 05/08/2009] [Indexed: 10/20/2022]
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17
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Crespi F. Anxiolytics antagonize yohimbine-induced central noradrenergic activity: A concomitant in vivo voltammetry–electrophysiology model of anxiety. J Neurosci Methods 2009; 180:97-105. [DOI: 10.1016/j.jneumeth.2009.03.007] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2008] [Revised: 02/27/2009] [Accepted: 03/09/2009] [Indexed: 10/21/2022]
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18
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Johnson MD, Franklin RK, Gibson MD, Brown RB, Kipke DR. Implantable microelectrode arrays for simultaneous electrophysiological and neurochemical recordings. J Neurosci Methods 2008; 174:62-70. [PMID: 18692090 PMCID: PMC2743487 DOI: 10.1016/j.jneumeth.2008.06.036] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2008] [Revised: 06/28/2008] [Accepted: 06/28/2008] [Indexed: 11/16/2022]
Abstract
Implantable microfabricated microelectrode arrays represent a versatile and powerful tool to record electrophysiological activity across multiple spatial locations in the brain. Spikes and field potentials, however, correspond to only a fraction of the physiological information available at the neural interface. In urethane-anesthetized rats, microfabricated microelectrode arrays were implanted acutely for simultaneous recording of striatal local field potentials, spikes, and electrically evoked dopamine overflow on the same spatiotemporal scale. During these multi-modal recordings we observed (1) that the amperometric method used to detect dopamine did not significantly influence electrophysiological activity, (2) that electrical stimulation in the medial forebrain bundle (MFB) region resulted in electrochemically transduced dopamine transients in the striatum that were spatially heterogeneous within at least 200 microm, and (3) following MFB stimulation, dopamine levels and electrophysiological activity within the striatum exhibited similar temporal profiles. These neural probes are capable of incorporating customized microelectrode geometries and configurations, which may be useful for examining specific spatiotemporal relationships between electrical and chemical signaling in the brain.
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Affiliation(s)
- Matthew D. Johnson
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, USA
| | - Robert K. Franklin
- Department of Electrical Engineering and Computer Science, University of Michigan, Ann Arbor, USA
- Department of Electrical and Computer Engineering, University of Utah, Salt Lake City, USA
| | - Matthew D. Gibson
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, USA
| | - Richard B. Brown
- Department of Electrical and Computer Engineering, University of Utah, Salt Lake City, USA
| | - Daryl R. Kipke
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, USA
- Department of Electrical Engineering and Computer Science, University of Michigan, Ann Arbor, USA
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19
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Johnson M, Franklin R, Scott KA, Brown R, Kipke D. Neural Probes for Concurrent Detection of Neurochemical and Electrophysiological Signals in vivo. CONFERENCE PROCEEDINGS : ... ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL CONFERENCE 2007; 2005:7325-8. [PMID: 17281972 DOI: 10.1109/iembs.2005.1616203] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
Electrochemical sensing with microelectrode arrays provides a means for monitoring neurotransmitter dynamics across multiple locations within a micro-scale region of brain tissue. Here we present a multi-modal neural probe design for concurrent recording of neurochemical and electrophysiological signals in vivo. Prior to implantation, platinum sites on each array underwent platinum-black electroplating and Nafion electropolymerization, which increased sensitivity to dopamine by 74% and decreased sensitivity to common interferents by at least 89%. In a series of three rats, we applied various electrochemical waveforms to platinum sites and monitored neural activity on adjacent iridium sites. We found that chronoamperometry and constant-potential amperometry did not alter firing rates at +0.25, +0.50, and +0.75 V. In addition, we have demonstrated multi-modal recordings of striatal neurons in response to medial forebrain bundle stimulation.
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Affiliation(s)
- M Johnson
- Department of Biomedical Engineering, University of Michigan, MI, USA
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Yavich L, Jäkälä P, Tanila H. Noradrenaline overflow in mouse dentate gyrus following locus coeruleus and natural stimulation: real-time monitoring by in vivo voltammetry. J Neurochem 2005; 95:641-50. [PMID: 16248883 DOI: 10.1111/j.1471-4159.2005.03390.x] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The pattern of catecholaminergic innervation of the dentate gyrus (DG) of the hippocampus, particularly the relatively dense and selective noradrenergic input, creates favourable conditions for real-time monitoring of noradrenaline (NA) release following stimulation of the locus coeruleus (LC) by in vivo voltammetry. Two electrochemically active species with different temporal characteristics were registered in the DG following electrical stimulation of the LC. Several approaches, including testing of anatomical and pharmacological specificity, coating of microelectrodes with Nafion and use of fast cyclic voltammetry, were used to verify the characteristics of electrochemical responses. The first sharp peak that appeared immediately during stimulation was definitely associated with NA overflow. The second late peak was possibly attributable to ascorbic acid. We examined the characteristics of alpha-2 adrenoceptor regulation of NA release in the DG, and showed for the first time that noradrenergic terminals resemble dopaminergic terminals in their mechanisms of increasing the refilling rate of the readily releasable pool following stimulation repeated at short intervals. Amperometric registration of NA in the DG was complicated by interference with electrical activity of hippocampus. This interference could be used, after appropriate filtration, for simultaneous recording from the same microelectrode of NA release and electrical activity of the hippocampus.
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Affiliation(s)
- Leonid Yavich
- Department of Pharmacology and Toxicology, Universtiy of Kuopio, Kuopio, Finland.
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Crespi F, Dalessandro D, Annovazzi-Lodi V, Heidbreder C, Norgia M. In vivo voltammetry: from wire to wireless measurements. J Neurosci Methods 2005; 140:153-61. [PMID: 15589345 DOI: 10.1016/j.jneumeth.2004.06.018] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2004] [Accepted: 06/11/2004] [Indexed: 12/27/2022]
Abstract
A novel telemetric system based on either differential pulse voltammetry (DPV) or direct current amperometry (DCA) by using a diffused infrared transmission channel is presented. Unlike similar pre-existing instruments based on infrared transmission, the present system works on a single-way communication, thus avoiding problems related to cross-talking between two-way channels. The infrared channel is also immune from electromagnetic interferences from the surrounding environment. Further advancement is the development of an original miniaturised system (dimension 1cm x 1.2 cm x 0.5 cm) with reduced weight (5-6 g), suitable for affixing to the rat head and allowing real time telemetric monitoring using DCA sampling of neurotransmitters such as dopamine or serotonin every 100 ms. The set-up is based on a transmitter (TX) circuit mounted on the animal's head and connected to the electrodes inserted into its brain. The TX circuit generates the proper electrical signals for DPV or DCA, collects the electrical response of the brain and transmits it, via an infrared channel, to a receiving station (RX) interfaced with a personal computer. The PC performs the sampling and elaboration of polarographic traces in a flexible and programmable way.
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Affiliation(s)
- Francesco Crespi
- Department of Biology, Psychiatry CEDD, GlaxoSmithKline, Verona, Italy
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Different effects of pentobarbital and pentylenetetrazol on nitric oxide levels in rat frontal cortex. ACTA VET-BEOGRAD 2005. [DOI: 10.2298/avb0506367d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
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Crespi F, Croce AC, Fiorani S, Masala B, Heidbreder C, Bottiroli G. In vivo autofluorescence spectrofluorometry of central serotonin. J Neurosci Methods 2004; 140:67-73. [PMID: 15589336 DOI: 10.1016/j.jneumeth.2004.06.019] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2004] [Accepted: 06/11/2004] [Indexed: 11/22/2022]
Abstract
The autofluorescence properties of serotonin (5-HT) were investigated by light spectrofluorometry in in vitro, ex vivo and in vivo experiments. Ex vivo samples were prepared from rat brain regions containing serotonin (5-HT) i.e. cortex, striatum, hippocampus. Rats were untreated (controls) or previously submitted to chronic behavioural or pharmacological treatments known to affect endogenous 5-HT levels. Autofluorescence analysis (excitation: 366 nm) on hippocampus homogenates supplied with exogenous 5-HT revealed spectral alterations attributable to changes of endogenous 5-HT levels. In vivo, real time fluorescence studies were performed via a 50 microm diameter optic fiber probe stereotaxically implanted into selected brain areas of anaesthetised rats treated with fluoxetine or 5-OH-tryptophan. All autofluorescence data were consistent with those obtained in parallel experiments performed with ex vivo or in vivo voltammetry, confirming that auto-fluorescence spectroscopy is a suitable technique for the direct assessment of fluorescent neurotransmitters. This is a reliable evidence of the in vivo application of spectroscopy together with optic fiber probe for in vivo, in situ and real time measurement of 5-HT in discrete brain areas.
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Affiliation(s)
- Francesco Crespi
- Department of Biology, Psychiatry C.E.D.D., GlaxoSmithKline S.p.A., Verona, Italy
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Shyu BC, Lin CY, Sun JJ, Chen SL, Chang C. BOLD response to direct thalamic stimulation reveals a functional connection between the medial thalamus and the anterior cingulate cortex in the rat. Magn Reson Med 2004; 52:47-55. [PMID: 15236366 DOI: 10.1002/mrm.20111] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Recent functional neuroimaging studies in humans and rodents have shown that the anterior cingulate cortex (ACC) is activated by painful stimuli, and plays an important role in the affective aspect of pain sensation. The aim of the present study was to develop a suitable stimulation method for direct activation of the brain in fMRI studies and to investigate the functional connectivity in the thalamo-cingulate pathway. In the first part of the study, tungsten, stainless steel, or glass-coated carbon fiber microelectrodes were implanted in the left medial thalamus (MT) of anesthetized rats, and T2*-weighted gradient-echo (GE) images were obtained in the sagittal plane on a 4.7 T system (Biospec BMT 47/40). Only the images obtained with the carbon fiber electrode were acceptable without a reduction of the signal-to-noise ratio (SNR) and image distortion. In the second part of the study, a series of two-slice GE images were acquired during electrical stimulation of the MT with the use of a carbon fiber electrode. A cross-correlation analysis showed that the signal intensities of activated areas in the ipsilateral ACC were significantly increased by about 4.5% during MT stimulation. Functional activation, as assessed by the distribution of c-Fos immunoreactivity, showed strong c-Fos expression in neurons in the ipsilateral ACC. The present study shows that glass-coated carbon fiber electrodes are suitable for fMRI studies and can be used to investigate functional thalamocortical activation.
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Affiliation(s)
- Bai-Chung Shyu
- Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan, Republic of China.
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Shyu BC, Lin CY, Sun JJ, Sylantyev S, Chang C. A method for direct thalamic stimulation in fMRI studies using a glass-coated carbon fiber electrode. J Neurosci Methods 2004; 137:123-31. [PMID: 15196834 DOI: 10.1016/j.jneumeth.2004.02.015] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2003] [Revised: 02/13/2004] [Accepted: 02/16/2004] [Indexed: 10/26/2022]
Abstract
Recent fMRI studies are of interest in exploring long-range interactions between different brain structures and the functional activation of specific brain regions by known neuroanatomical pathways. One of the experimental approaches requires the invasive implantation of an intracranial electrode to excite specific brain structures. In the present report, we describe a procedure for the production of a glass-coated carbon fiber electrode and the use of this electrode for direct activation of the brain in fMRI studies. The glass-coated carbon fiber microelectrode was implanted in the medial thalamus of anaesthetized rats and T2*-weighted gradient echo images in the sagittal plane obtained on a 4.7 T system (Biospec BMT 47/40) during electrical stimulation of the medial thalamus. The image quality obtained using this electrode was acceptable without reduction of the signal-to-noise ratio and image distortion. Cross-correlation analysis showed that the signal intensities of activated areas in the ipsilateral anterior cingulate cortex were significantly increased by about 4-5% during medial thalamus stimulation. The present study shows that glass-coated carbon fiber electrodes are suitable for fMRI studies and can be used to investigate functional thalamocingulate activation.
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Affiliation(s)
- Bai-Chuang Shyu
- Institute of Biomedical Sciences, Academia Sinica, Taipei 115, Taiwan, ROC.
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Crespi F, Croce AC, Fiorani S, Masala B, Heidbreder C, Bottiroli G. Autofluorescence Spectrofluorometry of central nervous system (CNS) neuromediators. Lasers Surg Med 2004; 34:39-47. [PMID: 14755423 DOI: 10.1002/lsm.10240] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
BACKGROUND AND OBJECTIVES Changes in the neurotransmitter 5-hydroxytriptamine (5-HT) are related to psychiatric diseases such as depression and anxiety. In this study, 5-HT autofluorescence properties were investigated in solution and in biological tissues. STUDY DESIGN/MATERIALS AND METHODS Spectrofluorometric characterization was performed on ex vivo samples (tissue sections, homogenates) of the 5-HT-rich brain region hippocampus from rats untreated or treated to affect endogenous 5-HT levels; in vivo, with a 50 solidus in circle optic fiber probe positioned via stereotaxis. RESULTS 5-HT exhibited minor excitation and emission bands at wavelengths longer than the well known excitation and emission bands in the UV region, 250-320 nm. Spectrofluorometric measurements under 366 nm excitation on homogenates supplied with 5-HT or belonging to treated rats revealed spectral alterations attributable to changes in the amount of 5-HT. Ex vivo and in vivo autofluorescence data were consistent with those obtained by conventional voltammetry. CONCLUSIONS Autofluorescence spectroscopy potential is confirmed as a suitable technique for the direct measurement of neurotransmitters.
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Affiliation(s)
- Francesco Crespi
- Department of Biology, Psychiatry C.E.D.D., GlaxoSmithKline S.p.A., Verona, Italy
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Heidbreder CA, Bianchi M, Lacroix LP, Faedo S, Perdona E, Remelli R, Cavanni P, Crespi F. Evidence that the metabotropic glutamate receptor 5 antagonist MPEP may act as an inhibitor of the norepinephrine transporter in vitro and in vivo. Synapse 2003; 50:269-76. [PMID: 14556231 DOI: 10.1002/syn.10261] [Citation(s) in RCA: 64] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The mechanisms through which blockade of metabotropic glutamate receptors 5 (mGluR5) results in anxiolytic and antidepressant effects are currently unknown. In the present study, we therefore hypothesized that the anxiolytic- and antidepressant-like profile of the noncompetitive mGluR5 receptor antagonist 2-ethyl-6-(phenylethynyl)-pyridine (MPEP) may be mediated by inhibition of the norepinephrine transporter (NET). Accordingly, we first examined the potency of MPEP to bind to or inhibit uptake at the NET as well as the dopamine and serotonin transporters (DAT and SERT, respectively). We also examined the simultaneous in vivo effects of MPEP and desipramine (DMI) on both NE-like oxidation current in the amygdala (AMY) and cell firing in the locus coeruleus (LC) by means of differential pulse voltammetry (DPV) coupled with electrophysiology. MPEP completely displaced the binding of [3H]-nisoxetine on human NET with a pKi of 6.63 +/- 0.02. In addition, MPEP was able to inhibit [3H]-NE uptake in LLCPK cells expressing human NET, with a pIC50 of 5.55 +/- 0.09. In vivo DPV data revealed that both MPEP (30 mg/kg i.p.) and DMI (10 mg/kg i.p.) significantly increased NE-like voltammetric responses levels in the AMY, whereas both compounds also significantly decreased cell firing monitored concomitantly from the second microelectrode in the LC. Collectively, the results of the present study provide potential new mechanisms through which MPEP exerts its anxiolytic and antidepressant effects.
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Affiliation(s)
- Christian A Heidbreder
- Department of Biology, Center of Excellence for Drug Discovery in Psychiatry, GlaxoSmithKline Pharmaceuticals, 37135 Verona, Italy.
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Crespi F. In vivo voltammetry and concomitant electrophysiology at a single micro-biosensor to analyse ischaemia, depression and drug dependence. J Neurosci Methods 2002; 119:173-84. [PMID: 12323421 DOI: 10.1016/s0165-0270(02)00176-0] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Electrochemical methods such as voltammetry can be used to understand patho-physiological mechanisms of action and, therefore, develop therapeutic approaches. In particular, voltammetry with treated micro-biosensors (carbon fibre micro-electrodes, mCFE) has been used to study models of (1) ischaemia; (2) drug dependence, and in particular craving; (3) depression. In addition, in studies (1) and (3) concomitant in vivo voltammetric and electrophysiological analysis has been performed by means of the same mCFE. Original data concerning ascorbate release in ischaemia, peptidergic activity during craving for drugs of abuse and concomitant voltammetric and electrophysiological changes of the serotonergic system in rats submitted to forced swimming test or to pharmacological treatment with the selective serotonin reuptake inhibitor fluoxetine are shown and discussed.
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Affiliation(s)
- Francesco Crespi
- Biology Department, Psychiatry-CEDD, Medicines Research Centre, GlaxoSmithKline SpA, via Fleming 4, 37135 Verona, Italy.
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Hentall ID, Kurle PJ, White TR. Correlations between serotonin level and single-cell firing in the rat's nucleus raphe magnus. Neuroscience 2000; 95:1081-8. [PMID: 10682715 DOI: 10.1016/s0306-4522(99)00516-3] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The relation between serotonin release and electrical activity was examined in the nucleus raphe magnus of rats anesthetized with pentobarbital. Serotonin levels were monitored through a carbon-fiber microelectrode by fast cyclic voltammetry (usually at 1 Hz). Single-cell firing was recorded through the same microelectrode, except during the voltammetry waveform and associated electrical artifact (totaling about 30 ms). Multi-barrel micropipettes incorporating the voltammetry electrode were used for iontophoresis of drugs. Cells were inhibited, excited or unaffected by noxious mechanical skin stimulation. These were respectively designated as off(M) cells, on(M) cells and neutral(M) cells, M denoting mechanical. During 3 min of pinching, serotonin slowly rose near seven of 14 on(M) cells and 26 of 46 off(M) cells; it fell near two off(M) cells; it was unchanged near all other cells, including six neutral(M) cells. On a finer spatiotemporal scale, near four of seven on(M) cells, 10 of 14 off(M) cells and 0 of four neutral(M) cells, average serotonin levels fell significantly within +/- 100 ms of spontaneous spikes. Lower serotonin may have caused the higher spike probability; the converse is theoretically unlikely, since delays between release and detection are estimated to exceed 100 ms. Increased serotonin and decreased firing were always seen following iontophoresis or intravenous injection (1 mg/kg) of the serotonin re-uptake inhibitor clomipramine (n = 7). Iontophoresis of +/- propranolol, whose serotonergic actions include antagonism and partial agonism at 5-HT1 receptors, also increased serotonin and decreased firing (n=4). Methiothepin (intravenous, 1 mg/kg), whose serotonergic actions include 5-HT1 and 5-HT2 antagonism, typically raised serotonin levels (four of five cells) and always blocked inhibition by clomipramine (n = 3). Iontophoresis of glutamate always lowered serotonin and increased firing (n = 4). Since serotonin levels and firing were usually inversely correlated, except near on(M) cells during pinch, we propose that serotonin is released from terminals of incoming nociceptive afferents. Prior neuroanatomical knowledge favors a midbrain origin for these afferents, while some of the drug findings suggest that their terminals possess inhibitory serotonergic autoreceptors, possibly of 5-HT1b subtype. The released serotonin could contribute to the inhibition of off(M) cells and excitation of on(M) cells by noxious stimulation, since inhibitory 5-HT1a receptors and excitatory 5-HT2 receptors, respectively, have previously been shown to dominate their serotonergic responses.
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Affiliation(s)
- I D Hentall
- University of Illinois College of Medicine, Rockford 61107-1897, USA
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Crespi F. Concomitant in vivo electrophysiological and voltammetric analysis indicate that ascorbic acid is a biochemical index of early ischaemia. Neurosci Lett 1996; 215:189-92. [PMID: 8899745 DOI: 10.1016/0304-3940(96)12974-8] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
A number of in vitro studies or in vivo cortical microdialysis measurements have observed that changes in the levels of ascorbic acid (AA), uric acid (UA), tryptophan (TRY), indoles and other compounds may be biochemical markers of cerebral ischaemic damages following occlusion of the rat middle cerebral artery (MCAO). The aim of the present work was to study the influence of early ischaemia upon presynaptic and postsynaptic activities in the cerebral cortex of rats. These activities have been studied by means of electrophysiological and electro-biochemical (voltammetric) measurements performed concomitantly every 5 min and applied with the same biosensor. The biosensor was inserted in the cerebral cortex of anaesthetised adult male rats which were then submitted to focal ischaemia via MCAO. Since changes in electrophysiological activity are considered marker of rise of ischaemia, the choice of simultaneous electrophysiological and electrochemical (voltammetric) analysis could allow the observation of specific biochemical(s) correlation(s) with the initial phase of ischaemia. The data obtained indicated that electrophysiological and voltammetric changes can be monitored simultaneously in the same brain region (i.e. effected by MCAO) by means of a single biosensor with an improved time resolution when compared with previous biochemical in vivo studies. In addition, a high correlation was observed between MCAO reduced functional responses of the neurons monitored by electrophysiology and increased levels of AA measured by voltammetry. This original observation suggests that AA is a biochemical marker of the very early stages of focal ischaemia and could be a useful tool for the evaluation of initial ischaemic damage.
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Affiliation(s)
- F Crespi
- GlaxoWellcome SpA, Medicines Research Centre, Verona, Italy
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