Kinetic Diversity of Striatal Dopamine: Evidence from a Novel Protocol for Voltammetry

Walters, Seth H.; Robbins, Elaine; Michael, Adrian C.

doi:10.1021/acschemneuro.6b00020

Cited by 10 publications

(10 citation statements)

References 51 publications

(101 reference statements)

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“…This can be beneficial to enhance chemical information by controlling the composition of specific analytes at the electrode surface. For example, the typical waveform used for catecholamine detection can be transformed, so that the starting potential is +0.33 V, instead of a negative potential . This N-shaped waveform generates a surface with a positive charge during the accumulation period between scans.…”

Section: Waveform Developmentmentioning

confidence: 99%

“…For example, the typical waveform used for catecholamine detection can be transformed, so that the starting potential is +0.33 V, instead of a negative potential. 69 This N-shaped waveform generates a surface with a positive charge during the accumulation period between scans. The resulting voltammogram exhibits less redox current for the oxidation of catecholamines, as the surface coverage of these molecules (positively charged at physiological pH) is diminished.…”

Section: Analytical Chemistrymentioning

confidence: 99%

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Fast-Scan Cyclic Voltammetry: Chemical Sensing in the Brain and Beyond

2017

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Section: Waveform Developmentmentioning

confidence: 99%

Section: Analytical Chemistrymentioning

confidence: 99%

Fast-Scan Cyclic Voltammetry: Chemical Sensing in the Brain and Beyond

2017

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“…Essentially, the model posits that dopamine is released into an inner compartment (IC) and then crosses a diffusion-slowing barrier to enter the outer compartment (OC), where it encounters the FSCV carbon fiber electrode and is taken up by DAT. This original RD model makes excellent ( R 2 > 0.99) fits to individual observed dopamine FSCV responses under drug naive conditions and with exposure to nearly all drugs in vivo ,, and in brain slices , (Figure A, bottom).…”

Section: Resultsmentioning

confidence: 96%

“…As with (see A), but the inclusion of an uptake term in the inner compartment (k Ui ) as a fifth adjustable model parameter permits all traces to be objectively fit with the same k T value (k T = 0.21). R 2 , in order = 0.99, 0.98, 0.99, 0.99, 0.97, 0.96, 0.96. individual observed dopamine FSCV responses under drug naive conditions and with exposure to nearly all drugs in vivo 12,13,24 and in brain slices 14,25 (Figure 1A, bottom). However, there are cases in which the original RD model fails to fit evoked dopamine data.…”

Section: ■ Introductionmentioning

confidence: 93%

Regional Variation in Striatal Dopamine Spillover and Release Plasticity

Walters

Zhan

Michael

et al. 2020

ACS Chem. Neurosci.

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Recent optical observations of dopamine at axon terminals and kinetic modeling of evoked dopamine responses measured by fast scan cyclic voltammetry (FSCV) support local restriction of dopamine diffusion at synaptic release sites. Yet, how this diffusion barrier affects synaptic and volume transmission is unknown. Here, a deficiency in a previous kinetic model's fitting of stimulus trains is remedied by replacing an earlier assumption that dopamine transporters (DATs) are present only on the outer side of the diffusion barrier with the assumption that they are present on both sides. This is consistent with the known distribution of DATs, which does not show obvious DAT-free zones proximal to dopamine release sites. A simultaneous multifitting strategy is then shown to enable unique model fits to sets of evoked dopamine FSCV responses acquired in vivo or in brain slices. This data analysis technique permits, for the first time, the calculation of the fraction of dopamine which spills over from what appears to be the perisynaptic space, as well as other parameters such as dopamine release, release plasticity, and uptake. This analysis shows that dopamine's diffusion away from its release sites is remarkably hindered (τ = 5 s), but dopamine responses are rapid because of DAT activity. Furthermore, the new analysis reveals that uptake inhibitors can inhibit dopamine release during a stimulus train, apparently by depleting the releasable pool. It is suggested that ongoing uptake is critical for maintaining ongoing synaptic dopamine release and that the previously reported and also herein claimed increase of the initial dopamine release of some uptake inhibitors might be an important mechanism in addiction. Finally, brain mapping data reveal that the diffusion barrier is conserved, but there are variations in perisynaptic uptake, volume transmission, and release plasticity within the rat striatum. Therefore, an analysis paradigm is developed to quantify previously unmeasured features of brain dopaminergic transmission and to reveal regional functional differences among dopamine synapses.

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“…It is stored in submicrometer-sized vesicles and eventually ejected into the synaptic cleft (exocytosis). , The electrochemical detection of DA in vitro and in vivo is essential for understanding its pathways and functions in nervous system. Wightman and his former students have pioneered the use of carbon ultramicroelectrodes to monitor DA exocytosis. − Several types of carbon-nanotube-based microelectrodes have been fabricated and employed as neurochemical sensors. − …”

mentioning

confidence: 99%

Ultrasensitive Detection of Dopamine with Carbon Nanopipets

Wang

Zhou

et al. 2019

Anal. Chem.

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Carbon fiber micro- and nanoelectrodes have been extensively used to measure dopamine and other neurotransmitters in biological systems. Although the radii of some reported probes were ≪1 μm, the lengths of the exposed carbon were typically on the micrometer scale, thus limiting the spatial resolution of electroanalytical measurements. Recent attempts to determine neurotransmitters in single cells and vesicles have provided additional impetus for decreasing the probe dimensions. Here, we report two types of dopamine sensors based on carbon nanopipets (CNP) prepared by chemical vapor deposition of carbon into prepulled quartz capillaries. These include 10–200 nm radius CNPs with a cavity near the orifice and CNPs with an open path in the middle, in which the volume of sampled solution can be controlled by the applied pressure. Because of the relatively large surface area of carbon exposed to solution inside the pipet, both types of sensors yielded well-shaped voltammograms of dopamine down to ca. 1 nM concentrations, and the unprecedented voltammetric response to 100 pM dopamine was obtained with open CNPs. TEM tomography and numerical simulations were used to model CNP responses. The effect of dopamine adsorption on the CNP detection limit is discussed along with the possibilities of measuring other physiologically important analytes (e.g., serotonin) and eliminating anionic and electrochemically irreversible interferences (e.g., ascorbic acid).

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Kinetic Diversity of Striatal Dopamine: Evidence from a Novel Protocol for Voltammetry

Cited by 10 publications

References 51 publications

Fast-Scan Cyclic Voltammetry: Chemical Sensing in the Brain and Beyond

Fast-Scan Cyclic Voltammetry: Chemical Sensing in the Brain and Beyond

Regional Variation in Striatal Dopamine Spillover and Release Plasticity

Ultrasensitive Detection of Dopamine with Carbon Nanopipets

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