scholarly journals Real-Time Fast Scan Cyclic Voltammetry Detection and Quantification of Exogenously Administered Melatonin in Mice Brain

2020 ◽  
Vol 8 ◽  
Author(s):  
Elisa Castagnola ◽  
Elaine M. Robbins ◽  
Kevin M. Woeppel ◽  
Moriah McGuier ◽  
Asiyeh Golabchi ◽  
...  
Keyword(s):  
Cyclic Voltammetry ◽  
Real Time ◽  
Mouse Brain ◽  
Activated Carbon Fiber ◽  
Carbon Surface ◽  
Fast Scan Cyclic Voltammetry ◽  
Brain Functions ◽  
The Brain

Melatonin (MT) has been recently considered an excellent candidate for the treatment of sleep disorders, neural injuries, and neurological diseases. To better investigate the actions of MT in various brain functions, real-time detection of MT concentrations in specific brain regions is much desired. Previously, we have demonstrated detection of exogenously administered MT in anesthetized mouse brain using square wave voltammetry (SWV). Here, for the first time, we show successful detection of exogenous MT in the brain using fast scan cyclic voltammetry (FSCV) on electrochemically pre-activated carbon fiber microelectrodes (CFEs). In vitro evaluation showed the highest sensitivity (28.1 nA/μM) and lowest detection limit (20.2 ± 4.8 nM) ever reported for MT detection at carbon surface. Additionally, an extensive CFE stability and fouling assessment demonstrated that a prolonged CFE pre-conditioning stabilizes the background, in vitro and in vivo, and provides consistent CFE sensitivity over time even in the presence of a high MT concentration. Finally, the stable in vivo background, with minimized CFE fouling, allows us to achieve a drift-free FSCV detection of exogenous administered MT in mouse brain over a period of 3 min, which is significantly longer than the duration limit (usually < 90 s) for traditional in vivo FSCV acquisition. The MT concentration and dynamics measured by FSCV are in good agreement with SWV, while microdialysis further validated the concentration range. These results demonstrated reliable MT detection using FSCV that has the potential to monitor MT in the brain over long periods of time.

scholarly journals Microelectrode Sensor for Real-Time Measurements of Nitrite in the Living Brain, in the Presence of Ascorbate

Biosensors ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 277
Author(s):  
Tiago Monteiro ◽  
Cândida Dias ◽  
Cátia F. Lourenço ◽  
Ana Ledo ◽  
Rui M. Barbosa ◽  
...  
Keyword(s):  
Blood Flow ◽  
Real Time ◽  
Brain Research ◽  
Electrochemical Techniques ◽  
Spatial Dynamics ◽  
Fast Scan Cyclic Voltammetry ◽  
Hypoxic Conditions ◽  
The Brain

The impaired blood flow to the brain causes a decrease in the supply of oxygen that can result in cerebral ischemia; if the blood flow is not restored quickly, neuronal injury or death will occur. Under hypoxic conditions, the production of nitric oxide (●NO), via the classical L-arginine–●NO synthase pathway, is reduced, which can compromise ●NO-dependent vasodilation. However, the alternative nitrite (NO2−) reduction to ●NO, under neuronal hypoxia and ischemia conditions, has been viewed as an in vivo storage pool of ●NO, complementing its enzymatic synthesis. Brain research is thus demanding suitable tools to probe nitrite’s temporal and spatial dynamics in vivo. In this work, we propose a new method for the real-time measurement of nitrite concentration in the brain extracellular space, using fast-scan cyclic voltammetry (FSCV) and carbon microfiber electrodes as sensing probes. In this way, nitrite was detected anodically and in vitro, in the 5–500 µM range, in the presence of increasing physiological concentrations of ascorbate (100–500 µM). These sensors were then tested for real-time and in vivo recordings in the anesthetized rat hippocampus; using fast electrochemical techniques, local and reproducible transients of nitrite oxidation signals were observed, upon pressure ejection of an exogenous nitrite solution into the brain tissue. Nitrite microsensors are thus a valuable tool for investigating the role of this inorganic anion in brain redox signaling.

scholarly journals Emergence Of Consciousness And Qualia From A Complex Brain

Folia Medica ◽  
2014 ◽  
Vol 56 (4) ◽  
pp. 289-296
Author(s):  
Jakob Korf
Keyword(s):  
System Theory ◽  
General System ◽  
Resolution Power ◽  
Brain Functions ◽  
Scientific Exploration ◽  
Brain Changes ◽  
Higher Brain Functions ◽  
The Brain

Abstract Qualia are private conscious experiences of which the associated feelings can be reported to other people. Whether qualia are amenable to scientific exploration has often been questioned, which is challenged by the present article. The following arguments are given: 1. the configuration of the brain changes continuously and irreversibly, because of genetic and environmental influences and interhuman communication; 2. qualia and consciousness are processes, rather than states; 3. private feelings, including those associated with qualia, should be positioned in the context of a personal brain as being developed during life; 4. consciousness and qualia should be understood in the context of general system theory, thus concluding that isolated, in vitro, properties of neurons and other brain constituents might marginally contribute to the understanding of higher brain functions, mind or qualia; 5. current in vivo approaches have too little resolution power - in terms of space and time - to delineate individual and subjective brain processes. When subtle personalized properties of the nervous system can be assessed in vivo or in vitro, qualia can scientifically be investigated. We discuss some approaches to overcome these barriers.

scholarly journals A study on Dowager Cixi’s Yanling-Yishou-Dan of Qing Dynasty in a Japanese laboratory of biochemistry and molecular biology in 1990s: An attempt for TCM modernization

2021 ◽  
pp. 1-21
Author(s):  
Jiankang Liu
Keyword(s):  
Qing Dynasty ◽  
Brain Homogenate ◽  
Modern Technology ◽  
Toxicity Tests ◽  
Brain Functions ◽  
Great Progress ◽  
Theoretical Evidence ◽  
The Brain

Traditional Chinese Medicine (TCM) modernization has been proposed for many years, but the progress is still slow due to both ideological and technical obstacles. When I went to Japan in 1989, I found Japan has made a great progress on TCM by using modern technology. Therefore, I have studied a fine extract prepared from medicinal herbs (renamed Yi-Zhi-Yi-Shou, YZYS), a prescription of Dowager Cixi’s Yanling-Yishou-Dan of Qing Dynasty, with the current drug investigation strategies. I examined its antioxidant activity both in vitro and in vivo. The in-vitro studies found that YZYS possesses strong antioxidant capacity, such as scavenging various kinds of free radicals, and inhibits free radical-induced peroxidation of brain homogenate, microsomes, mitochondria, amino acids, deoxyribose and DNA. The in-vivo study with immobilization-induced emotional stress in rats, showed that YZYS effectively inhibits stress-induced stomach ulcers and oxidative damage in plasma and the brain. In addition, YZYS is shown to be non-toxic in both acute and chronic toxicity tests. These studies demonstrate that YZYS is a potent natural antioxidant and offer theoretical evidence for the beneficial effect of YZYS on health and brain functions, and that TCM prescriptions can be studied scientifically as modern medical drugs.

Cannabinoid effects on adenylate cyclase and phosphodiesterase activities of mouse brain

1977 ◽  
Vol 55 (4) ◽  
pp. 934-942 ◽  
Author(s):  
Thomas W. Dolby ◽  
Lewis J. Kleinsmith
Keyword(s):  
Cyclic Amp ◽  
Adenylate Cyclase ◽  
Mouse Brain ◽  
Biogenic Amine ◽  
Specific Activity ◽  
Intraperitoneal Administration ◽  
The Brain

The experiments presented in this paper examine the mechanisms underlying the ability of cannabinoids to alter the in vivo levels of cyclic adenosine 3′,5′-monophosphate (cyclic AMP) in mouse brain. It was found that changes in cyclic AMP levels are a composite result of direct actions of cannabinoids on adenylate cyclase (EC 4.6.1.1) activity and indirect actions involving the potentiation or inhibition of biogenic amine induced activity of adenylate cyclase. Furthermore, the long-term intraperitoneal administration of 1-(−)-Δ-tetrahydrocannabinol to mice produced a form of phosphodiesterase (EC 3.1.4.17) in the brain whose activity is not stimulated by Ca2+, although its basal specific activity is similar to that of control animals. In vitro, the presence of the cannabinoids caused no significant changes in activity of brain PDE at the concentrations tested. Some correlations are presented which imply that many of the observed behavioral and physiological actions of the cannabinoids in mammalian organisms may be mediated via cyclic AMP mechanisms.

scholarly journals Live View of Gonadotropin-Releasing Hormone Containing Neuron Migration

Endocrinology ◽  
2005 ◽  
Vol 146 (1) ◽  
pp. 463-468 ◽  
Author(s):  
Elizabeth P. Bless ◽  
Heather J. Walker ◽  
Kwok W. Yu ◽  
J. Gabriel Knoll ◽  
Suzanne M. Moenter ◽  
...  
Keyword(s):  
Real Time ◽  
Direct Evidence ◽  
Gonadotropin Releasing Hormone ◽  
Releasing Hormone ◽  
Reproductive Axis ◽  
Gnrh Neurons ◽  
Migratory Route ◽  
The Brain

Neurons that synthesize GnRH control the reproductive axis and migrate over long distances and through different environments during development. Prior studies provided strong clues for the types of molecules encountered and movements expected along the migratory route. However, our studies provide the first real-time views of the behavior of GnRH neurons in the context of an in vitro preparation that maintains conditions comparable to those in vivo. The live views provide direct evidence of the changing behavior of GnRH neurons in their different environments, showing that GnRH neurons move with greater frequency and with more changes in direction after they enter the brain. Perturbations of guiding fibers distal to moving GnRH neurons in the nasal compartment influenced movement without detectable changes in the fibers in the immediate vicinity of moving GnRH neurons. This suggests that the use of fibers by GnRH neurons for guidance may entail selective signaling in addition to mechanical guidance. These studies establish a model to evaluate the influences of specific molecules that are important for their migration.

Striatal low-threshold spiking interneurons locally gate dopamine during learning

2020 ◽  
Author(s):  
Elizabeth N. Holly ◽  
M. Felicia Davatolhagh ◽  
Rodrigo A. España ◽  
Marc V. Fuccillo
Keyword(s):  
Cyclic Voltammetry ◽  
Dopamine Release ◽  
Striatal Dopamine ◽  
Operant Learning ◽  
Fast Scan Cyclic Voltammetry ◽  
Directed Learning ◽  
Low Threshold ◽  
Dorsomedial Striatum

Low-threshold spiking interneurons (LTSIs) in the dorsomedial striatum are potent modulators of goal-directed learning. Here, we uncover a novel function for LTSIs in locally and directly gating striatal dopamine, using in vitro fast scan cyclic voltammetry as well as in vivo GRAB-DA sensor imaging and pharmacology during operant learning. We demonstrate that LTSIs, acting via GABAB signaling, attenuate dopamine release, thereby serving as local coordinators of striatal plasticity.

scholarly journals Latest Trends in Electrochemical Sensors for Neurotransmitters: A Review

Sensors ◽  
2019 ◽  
Vol 19 (9) ◽  
pp. 2037 ◽  
Author(s):  
Tavakolian-Ardakani ◽  
Hosu ◽  
Cristea ◽  
Mazloum-Ardakani ◽  
Marrazza
Keyword(s):  
Electrochemical Sensors ◽  
Ex Vivo ◽  
Analytical Techniques ◽  
Substantial Improvement ◽  
Robust Detection ◽  
Brain Functions ◽  
The Brain ◽  
Made In

Neurotransmitters are endogenous chemical messengers which play an important role in many of the brain functions, abnormal levels being correlated with physical, psychotic and neurodegenerative diseases such as Alzheimer's, Parkinson's, and Huntington's disease. Therefore, their sensitive and robust detection is of great clinical significance. Electrochemical methods have been intensively used in the last decades for neurotransmitter detection, outclassing more complicated analytical techniques such as conventional spectrophotometry, chromatography, fluorescence, flow injection, and capillary electrophoresis. In this manuscript, the most successful and promising electrochemical enzyme-free and enzymatic sensors for neurotransmitter detection are reviewed. Focusing on the activity of worldwide researchers mainly during the last ten years (2010–2019), without pretending to be exhaustive, we present an overview of the progress made in sensing strategies during this time. Particular emphasis is placed on nanostructured-based sensors, which show a substantial improvement of the analytical performances. This review also examines the progress made in biosensors for neurotransmitter measurements in vitro, in vivo and ex vivo.

scholarly journals Design Choices for Next-Generation Neurotechnology Can Impact Motion Artifact in Electrophysiological and Fast-Scan Cyclic Voltammetry Measurements

Micromachines ◽  
2018 ◽  
Vol 9 (10) ◽  
pp. 494 ◽  
Author(s):  
Evan Nicolai ◽  
Nicholas Michelson ◽  
Megan Settell ◽  
Seth Hara ◽  
James Trevathan ◽  
...  
Keyword(s):  
Cyclic Voltammetry ◽  
Electrode Materials ◽  
Motion Artifact ◽  
Next Generation ◽  
Fast Scan Cyclic Voltammetry ◽  
Flexible Electrodes ◽  
In Vivo Experiments ◽  
Electrophysiological Recordings

Implantable devices to measure neurochemical or electrical activity from the brain are mainstays of neuroscience research and have become increasingly utilized as enabling components of clinical therapies. In order to increase the number of recording channels on these devices while minimizing the immune response, flexible electrodes under 10 µm in diameter have been proposed as ideal next-generation neural interfaces. However, the representation of motion artifact during neurochemical or electrophysiological recordings using ultra-small, flexible electrodes remains unexplored. In this short communication, we characterize motion artifact generated by the movement of 7 µm diameter carbon fiber electrodes during electrophysiological recordings and fast-scan cyclic voltammetry (FSCV) measurements of electroactive neurochemicals. Through in vitro and in vivo experiments, we demonstrate that artifact induced by motion can be problematic to distinguish from the characteristic signals associated with recorded action potentials or neurochemical measurements. These results underscore that new electrode materials and recording paradigms can alter the representation of common sources of artifact in vivo and therefore must be carefully characterized.

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