Subsecond Adsorption and Desorption of Dopamine at Carbon-Fiber Microelectrodes

Bath, Bradley D.; Michael, Darren J.; Trafton, B. Jill; Joseph, Joshua D.; Runnels, and Petrise L.; Wightman, R. Mark

doi:10.1021/ac000849y

Cited by 337 publications

(571 citation statements)

References 30 publications

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“…The delayed response of CV was previously reported, for neurotransmitters, and mostly attributed to adsorption of the analyte to the electrode surface. 21,22 By using an outer-sphere redox couple, we show that mass transport also significantly delays the response of CV. Analyte adsorption, in the case of an inner-sphere electron transfer, was not considered in our analysis, and the respective contribution of this phenomenon and mass transport cannot yet be elucidated.…”

Section: Discussionmentioning

confidence: 90%

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Delayed voltammetric with respect to amperometric electrochemical detection of concentration changes in microchannels

Trouillon

Gijs

2014

Lab Chip

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ARTICLEThis journal is © The Royal Society of Chemistry 2013 J. Name., 2013, 00, 1-3 | 1 The time response of an electrode incorporated into a fluidic channel to variations in analyte concentration of the outer-sphere redox probe ferrocenemethanol was investigated, both for amperometry (AMP) and cyclic voltammetry (CV). The experimental data show that the temporal resolution of CV is not as good as for AMP, as CV cannot properly detect fast concentration transients. The delayed response of CV was previously reported, for neurotransmitters, and mostly attributed to adsorption of the analyte to the electrode surface. By using an outer-sphere redox couple, we show that mass transport also significantly delays the response of CV. The experimental delay time in CV was understood from mass transfer limitations due to the relaxation of the diffusion layer during repeated potential scanning. Furthermore, a robust protocol for the analysis of fast concentration transients was established, using the impulse and modulation transfer functions of the system. This method was found to be more precise than the mere analysis of the undifferentiated traces in the time domain. As a proof of concept, the effect of increased viscosity was investigated, showing that AMP was more sensitive than CV to these variations. Overall, this analysis underlines further the enhanced temporal sensitivity of AMP over CV, at the expense of decreased chemical resolution, potentially having implications for in situ electrochemical detection of biologically relevant molecules.

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Section: Discussionmentioning

confidence: 90%

“…This delay was principally attributed to dopamine adsorption to the electrode surface, thus slowing the electrochemical response in the case of a fast potential ramp. 21,22 However, the role of mass transport in this delay has not been fully investigated in this particular case. The specificity of CV over AMP, i.e.…”

Section: Introductionmentioning

confidence: 99%

Delayed voltammetric with respect to amperometric electrochemical detection of concentration changes in microchannels

Trouillon

Gijs

2014

Lab Chip

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“…Electrodes were soaked for 30 min in isopropyl alcohol prior to use. 45 Postcalibration was carried out using freshly prepared, nitrogen-purged dopamine HCl (Sigma Aldrich, St. Louis, MO) standard solutions in artificial cerebrospinal fluid (144 mM Na + , 1.2 mM Ca 2+ , 2.7 mM K + , 1.0 mM Mg 2+ , 149.1 mM Cl − , and 2.0 mM phosphate, pH 7.4). Concentrations in vivo were obtained using postcalibration results.…”

Section: ■ Methodsmentioning

confidence: 99%

Restricted Diffusion of Dopamine in the Rat Dorsal Striatum

Taylor

Ilitchev

Michael

2013

ACS Chem. Neurosci.

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Recent evidence has shown that the dorsal striatum of the rat is arranged as a patchwork of domains that exhibit distinct dopamine kinetics and concentrations. This raises the pressing question of how these distinct domains are maintained, especially if dopamine is able to diffuse through the extracellular space. Diffusion between the domains would eliminate the concentration differences and, thereby, the domains themselves. The present study is a closer examination of dopamine's ability to diffuse in the extracellular space. We used voltammetry to record dopamine overflow in dorsal striatum while stimulating the medial forebrain bundle over a range of stimulus currents and frequencies. We also examined the effects of drugs that modulated the dopamine release (raclopride and quinpirole) and uptake (nomifensine). Examining the details of the temporal features of the evoked profiles reveals no clear evidence for long-distance diffusion of dopamine between fast and slow domains, even though uptake inhibition by nomifensine clearly prolongs the time that dopamine resides in the extracellular space. Our observations support the conclusion that striatal tissue has the capacity to retain dopamine molecules, thereby limiting its tendency to diffuse through the extracellular space. KEYWORDS: Dopamine, dopamine transporter, diffusion, evoked release, voltammetry, dorsal striatum C entral dopamine (DA) systems participate in numerous aspects of brain function, 1,2 and their dysfunction contributes to a broad array of disorders and diseases including Parkinson's disease, 3 schizophrenia, 4 and attention deficit hyperactivity disorder. 5 Broadly speaking, the physiological function of the DA molecules themselves is to bind to post-and presynaptic receptors to modulate the activity of the postsynaptic targets 6 and to self-regulate DAergic activity, 7 respectively. Consequently, numerous drugs act by modulating extracellular DA concentrations (e.g., L-DOPA, MAO inhibitors, and inhibitors of the dopamine transporter (DAT) 8−11 ) or by modulating or mimicking the binding of DA to its receptors (DA agonists and antagonists). 12,13 Some of the drugs that target DA systems have important therapeutic applications 14,15 while others have high potential for illicit abuse: 16−18 some therapeutic drugs are also abused. 19 Thus, it is significant to know the extracellular DA concentration per se, to know the kinetics of DA release and clearance that determine the concentration, and to know the actions of drugs that target DA systems.Recently, we have demonstrated that the DA terminal field in the rat dorsal striatum contains a patchwork of kinetic spatial domains. The fast and slow domains were brought to light by recordings of extracellular DA with fast-scan cyclic voltammetry (FSCV) at carbon fiber microelectrodes during electrical stimulation of the medial forebrain bundle (MFB). The extracellular concentration of DA, the kinetics of DA release and clearance, the short-term plasticity of DA release, and the actions of DA-ta...

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“…The time constant R accounts for the delays due to diffusion in the extracellular space and the response time of the electrode. That is, R characterizes the low pass filtering that occurs with this type of electrochemical measurement (Bath et al, 2000). For each fit of the model to the measured dopamine levels, the number of dynamic components I j and their polarity (facilitating or depressing) were preselected.…”

Section: Methodsmentioning

confidence: 99%

Dynamic Gain Control of Dopamine Delivery in Freely Moving Animals

Montague¹,

McClure²,

Baldwin³

et al. 2004

J. Neurosci.

157

151

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Activity changes in a large subset of midbrain dopamine neurons fulfill numerous assumptions of learning theory by encoding a prediction error between actual and predicted reward. This computational interpretation of dopaminergic spike activity invites the important question of how changes in spike rate are translated into changes in dopamine delivery at target neural structures. Using electrochemical detection of rapid dopamine release in the striatum of freely moving rats, we established that a single dynamic model can capture all the measured fluctuations in dopamine delivery. This model revealed three independent short-term adaptive processes acting to control dopamine release. These short-term components generalized well across animals and stimulation patterns and were preserved under anesthesia. The model has implications for the dynamic filtering interposed between changes in spike production and forebrain dopamine release.

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Subsecond Adsorption and Desorption of Dopamine at Carbon-Fiber Microelectrodes

Cited by 337 publications

References 30 publications

Delayed voltammetric with respect to amperometric electrochemical detection of concentration changes in microchannels

Delayed voltammetric with respect to amperometric electrochemical detection of concentration changes in microchannels

Restricted Diffusion of Dopamine in the Rat Dorsal Striatum

Dynamic Gain Control of Dopamine Delivery in Freely Moving Animals

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