Multi-waveform fast-scan cyclic voltammetry mapping of adsorption/desorption kinetics of biogenic amines and their metabolites

Kim, Do Hyoung,Oh, Yoonbae,Shin, Hojin,Park, Cheonho,Blaha, Charles D.,Bennet, Kevin E.,Kim, In Young,Lee, Kendall H.,Jang, Dong Pyo The Royal Society of Chemistry 2018 Analytical methods Vol.10 No.24

<P>Fast-scan cyclic voltammetry (FSCV) is an effective method for investigating electro-active neurochemical species. In recent years, FSCV has been used to measure electro-active neurotransmitters in a variety of neuroscience studies. We previously reported on the use of paired-pulse voltammetry (PPV) that enables FSCV to differentiate various analytes and minimize confounding factors by taking advantage of the adsorption characteristics of the analyte on carbon fiber microelectrodes. In spite of a number of studies regarding adsorption/desorption characteristics of neurotransmitters, the difference in adsorption/desorption properties among neurotransmitters has yet to be fully explored. To calculate adsorption/desorption constants for neurotransmitters, we propose the use of multi-waveform FSCV (M-FSCV), which consists of ten triangular waveforms in a single scan. Within the multiple waveforms, the voltammetric response of dopamine decayed exponentially because of the decreased adsorption time period. The decay pattern was mathematically described using adsorption/desorption characteristics and two additional initial points: an exponential decay constant (<I>K</I>) and an initial quantity (<I>A</I>), which were extracted from the decay equation. Using this method, we were able to quantify the decay constant (<I>K</I>-map) and an initial quantity (<I>A</I>-map) color plot in addition to a conventional pseudo color plot. M-FSCV was evaluated with two biogenic amine groups (catecholamines and indolamines) to characterize their inherent adsorption/desorption constants. As a result, the <I>A</I>-map showed a high correlation with concentration and the <I>K</I>-map for each group to be significantly differentiated. These results demonstrate that M-FSCV has the potential to be a useful technique for acquiring additional adsorption/desorption information regarding neurotransmitters.</P>

Sensitive and Selective Measurement of Serotonin <i>in Vivo</i> Using Fast Cyclic Square-Wave Voltammetry

Shin, Hojin,Oh, Yoonbae,Park, Cheonho,Kang, Yumin,Cho, Hyun U.,Blaha, Charles D.,Bennet, Kevin E.,Heien, Michael L.,Kim, In Young,Lee, Kendall H.,Jang, Dong Pyo American Chemical Society 2020 ANALYTICAL CHEMISTRY - Vol.92 No.1

<P>Although N-shaped fast scan cyclic voltammetry (N-FSCV) is well-established as an electroanalytical method to measure extracellular serotonin concentrations <I>in vivo</I>, it is in need of improvement in both sensitivity and selectivity. Based on our previous studies using fast cyclic square-wave voltammetry (FCSWV) for <I>in vivo</I> dopamine measurements, we have modified this technique to optimize the detection of serotonin <I>in vivo</I>. A series of large amplitude square-shaped potentials was superimposed onto an N-shaped waveform to provide cycling through multiple redox reactions within the N-shaped waveform to enhance the sensitivity and selectivity to serotonin measurement when combined with a two-dimensional voltammogram. N-Shaped fast cyclic square-wave voltammetry (N-FCSWV) showed significantly higher sensitivity to serotonin compared to conventional N-FSCV. In addition, N-FCSWV showed better performance than conventional N-shaped FSCV in differentiating serotonin from its major interferents, dopamine and 5-hydroxyindoleascetic acid (5-HIAA). It was also confirmed that the large amplitude of the square waveform did not influence local neuronal activity, and it could monitor electrical stimulation evoked phasic release of serotonin in the rat substantia nigra pars reticulata (SNr) before and after systemic injection of escitalopram (ESCIT, 10 mg/kg i.p.), a serotonin selective reuptake inhibitor.</P> [FIG OMISSION]</BR>

Deep Brain Stimulation: Technology at the Cutting Edge

Rahul S. Shah,Su-Youne Chang,민훈기,조장희,Charles D. Blaha,Kendall H. Lee 대한신경과학회 2010 Journal of Clinical Neurology Vol.6 No.4

Deep brain stimulation (DBS) surgery has been performed in over 75,000 people worldwide, and has been shown to be an effective treatment for Parkinson’s disease, tremor, dystonia, epilepsy,depression, Tourette’s syndrome, and obsessive compulsive disorder. We review current and emerging evidence for the role of DBS in the management of a range of neurological and psychiatric conditions, and discuss the technical and practical aspects of performing DBS surgery. In the future, evolution of DBS technology may depend on several key areas, including better scientific understanding of its underlying mechanism of action, advances in high-spatial resolution imaging and development of novel electrophysiological and neurotransmitter microsensor systems. Such developments could form the basis of an intelligent closed-loop DBS system with feedback-guided neuromodulation to optimize both electrode placement and therapeutic efficacy.

A baseline drift detrending technique for fast scan cyclic voltammetry

DeWaele, Mark,Oh, Yoonbae,Park, Cheonho,Kang, Yu Min,Shin, Hojin,Blaha, Charles D.,Bennet, Kevin E.,Kim, In Young,Lee, Kendall H.,Jang, Dong Pyo The Royal Society of Chemistry 2017 The Analyst Vol.142 No.22

<P>Fast scan cyclic voltammetry (FSCV) has been commonly used to measure extracellular neurotransmitter concentrations in the brain. Due to the unstable nature of the background currents inherent in FSCV measurements, analysis of FSCV data is limited to very short amounts of time using traditional background subtraction. In this paper, we propose the use of a zero-phase high pass filter (HPF) as the means to remove the background drift. Instead of the traditional method of low pass filtering across voltammograms to increase the signal to noise ratio, a HPF with a low cutoff frequency was applied to the temporal dataset at each voltage point to remove the background drift. As a result, the HPF utilizing cutoff frequencies between 0.001 Hz and 0.01 Hz could be effectively used to a set of FSCV data for removing the drifting patterns while preserving the temporal kinetics of the phasic dopamine response recorded <I>in vivo</I>. In addition, compared to a drift removal method using principal component analysis, this was found to be significantly more effective in reducing the drift (unpaired <I>t</I>-test <I>p</I> < 0.0001, <I>t</I> = 10.88) when applied to data collected from Tris buffer over 24 hours although a drift removal method using principal component analysis also showed the effective background drift reduction. The HPF was also applied to 5 hours of FSCV <I>in vivo</I> data. Electrically evoked dopamine peaks, observed in the nucleus accumbens, were clearly visible even without background subtraction. This technique provides a new, simple, and yet robust, approach to analyse FSCV data with an unstable background.</P>

Tracking tonic dopamine levels <i>in vivo</i> using multiple cyclic square wave voltammetry

Oh, Yoonbae,Heien, Michael L.,Park, Cheonho,Kang, Yu Min,Kim, Jaekyung,Boschen, Suelen Lucio,Shin, Hojin,Cho, Hyun U.,Blaha, Charles D.,Bennet, Kevin E.,Lee, Han Kyu,Jung, Sung Jun,Kim, In Young,Lee, Elsevier 2018 Biosensors & bioelectronics Vol.121 No.-

<P><B>Abstract</B></P> <P>For over two decades, fast-scan cyclic voltammetry (FSCV) has served as a reliable analytical method for monitoring dopamine release in near real-time <I>in vivo</I>. However, contemporary FSCV techniques have been limited to measure only rapid (on the order of seconds, <I>i.e.</I> phasic) changes in dopamine release evoked by either electrical stimulation or elicited by presentation of behaviorally salient stimuli, and not slower changes in the tonic extracellular levels of dopamine (<I>i.e.</I> basal concentrations). This is because FSCV is inherently a differential method that requires subtraction of prestimulation tonic levels of dopamine to measure phasic changes relative to a zeroed baseline. Here, we describe the development and application of a novel voltammetric technique, multiple cyclic square wave voltammetry (M-CSWV), for analytical quantification of tonic dopamine concentrations <I>in vivo</I> with relatively high temporal resolution (10 s). M-CSWV enriches the electrochemical information by generating two dimensional voltammograms which enable high sensitivity (limit of detection, 0.17 nM) and selectivity against ascorbic acid, and 3,4-dihydroxyphenylacetic acid (DOPAC), including changes in pH. Using M-CSWV, a tonic dopamine concentration of 120 ± 18 nM (n = 7 rats, ± SEM) was determined in the striatum of urethane anethetized rats. Pharmacological treatments to elevate dopamine by selectively inhibiting dopamine reuptake and to reduce DOPAC by inhibition of monoamine oxidase supported the selective detection of dopamine <I>in vivo</I>. Overall, M-CSWV offers a novel voltammetric technique to quantify levels and monitor changes in tonic dopamine concentrations in the brain to further our understanding of the role of dopamine in normal behavior and neuropsychiatric disorders.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Highly sensitive and selective electrochemical method for detecting tonic dopamine level <I>in vivo</I>. </LI> <LI> Enhanced visualization of the data by two-dimensional voltammogram of electrochemical responses. </LI> <LI> High temporal resolution (10 s). </LI> </UL> </P>

Fast Cyclic Square-Wave Voltammetry To Enhance Neurotransmitter Selectivity and Sensitivity

Park, Cheonho,Oh, Yoonbae,Shin, Hojin,Kim, Jaekyung,Kang, Yumin,Sim, Jeongeun,Cho, Hyun U.,Lee, Han Kyu,Jung, Sung Jun,Blaha, Charles D.,Bennet, Kevin E.,Heien, Michael L.,Lee, Kendall H.,Kim, In Youn American Chemical Society 2018 ANALYTICAL CHEMISTRY - Vol.90 No.22

<P>Although fast-scan cyclic voltammetry (FSCV) has been widely used for in vivo neurochemical detection, the sensitivity and selectivity of the technique can be further improved. In this study, we develop fast cyclic square-wave voltammetry (FCSWV) as a novel voltammetric technique that combines large-amplitude cyclic square-wave voltammetry (CSWV) with background subtraction. A large-amplitude, square-shaped potential was applied to induce cycling through multiple redox reactions within a square pulse to increase sensitivity and selectivity when combined with a two-dimensional voltammogram. As a result, FCSWV was significantly more sensitive than FSCV (<I>n</I> = 5 electrodes, two-way ANOVA, <I>p</I> = 0.0002). In addition, FCSWV could differentiate dopamine from other catecholamines (e.g., epinephrine and norepinephrine) and serotonin better than conventional FSCV. With the confirmation that FCSWV did not influence local neuronal activity, despite the large amplitude of the square waveform, it could monitor electrically induced phasic changes in dopamine release in rat striatum before and after injecting nomifensine, a dopamine reuptake inhibitor.</P> [FIG OMISSION]</BR>