Subsecond adsorption and desorption of dopamine at carbon-fiber microelectrodes
Subsecond adsorption and desorption of dopamine at carbon-fiber microelectrodes
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DOI：
10.1021/ac000849y
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发表时间：
2000-12-15
影响因子：
7.4
通讯作者：
Wightman, RM
中科院分区：
文献类型：
--
作者：
Bath, BD;Michael, DJ;Wightman, RM
用高重复性快速扫描循环伏安法和计时电流法定量和表征了多巴胺和多巴胺邻苯二酚在碳纤维微电极上的吸附和脱附动力学，用NOW进样分析系统精确地将亚秒量级的电活性物质引入和去除到由单一碳纤维(Thornel型T650或P55型)制成的盘状微电极上，电极表面的预处理包括在纯化的异丙醇中浸泡至少10min，使多巴胺的S/N比浸泡在试剂级溶剂中的电极增加200-400%。由于吸附，高扫描速率(2000V/S)与较慢的、更传统的扫描速率相比，显示出相当的S/N比。此外，当循环伏安扫描以短间隔(4ms)重复时，对浓度团注的稳态响应发生得更快。新的方法允许更准确地确定生物系统中神经递质释放事件(10-500ms)的动力学。用T650圆柱形微电极进行的脑切片和活体实验表明，采用2000V/S和240赫兹的伏安法测得的尾状核摄取动力学比300V/S和10赫兹的要快。
High-repetition fast-scan cyclic voltammetry and chronoamperometry were used to quantify and characterize the kinetics of dopamine and dopamine-o-quinone adsorption and desorption at carbon-fiber microelectrodes, A now injection analysis system was used for the precise introduction and removal of a bolus of electroactive substance on a sub-second time scale to the disk-shaped surface of a microelectrode that was fabricated from a single carbon fiber (Thornel type T650 or P55), Pretreatment of the electrode surfaces consisted of soaking them in purified isopropyl alcohol for a minimum of 10 min, which resulted in S/N increasing by 200-400% for dopamine above that for those that were soaked in reagent grade solvent. Because of adsorption, high scan rates (2000 V/s) are shown to exhibit equivalent S/N ratios as compared to slower, more traditional scan rates. In addition, the steady-state response to a concentration bolus is shown to occur more rapidly when cyclic voltammetric scans are repeated at short intervals (4 ms). The new methodologies allow for more accurate determinations of the kinetics of neurotransmitter release events (10-500 ms) in biological systems. Brain slice and in vivo experiments using T650 cylinder microelectrodes show that voltammetrically measured uptake kinetics in the caudate are faster using 2000 V/s and 240 Hz measurements, as compared to 300 V/s and 10 Hz.