In vivo measurement of tubular fluid ferrocyanide with carbon-fiber microelectrodes.
In vivo measurement of tubular fluid ferrocyanide with carbon-fiber microelectrodes.
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用碳纤维微电极体内测量管状液体亚铁氰化物。
DOI：
10.1152/ajprenal.1987.252.6.f1158
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发表时间：
1987
期刊：
影响因子：
--
通讯作者：
Birzgalis,A
中科院分区：
文献类型：
--
作者：
Moore,LC;Clausen,C;Bowden,EF;Birzgalis,A
描述了构建碳纤维微电极和测量单个肾元中亚铁氰化物离子浓度的技术。测量包括极化一个惰性碳纤维微电极相对于Ag-AgCl基准500 mV正值，同时测量由亚铁氰化物氧化产生的faradic电流。碳纤维（5-7微米直径）被热封在一个玻璃微移液管中，然后被削尖、硅化和电化学预处理，以尽量减少蛋白质对电极的降解。介绍了一种廉价的电压箝位电流监测器和数据采样装置的电路图。电极对大体积和极小体积（20nl）亚铁氰化物浓度的变化呈线性响应。电极用于电化学微分析，以确定近端微穿刺样品的管状流体与血浆亚铁氰化物浓度比和肾元滤过率。结果与[3H]菊粉的配对测定结果吻合良好。体内近端小管灌注实验显示，小管液亚铁氰化物浓度变化具有快速的线性响应。这些电极允许快速定量测量亚铁氰化物浓度和近端小管中的水运输，并可能在其他生物系统中有用。
Techniques to construct carbon-fiber microelectrodes and to measure ferrocyanide ion concentration in single nephrons are described. The measurement involves polarizing an inert carbon-fiber microelectrode 500 mV positive with respect to a Ag-AgCl reference, while measuring the faradic current produced by the oxidation of ferrocyanide. A carbon fiber (5-7 micron diam) is heat sealed into a glass micropipette that is then sharpened, silanized, and electrochemically pretreated to minimize electrode degradation by protein. Circuit diagrams for an inexpensive voltage clamp-current monitor and a data sampling device are presented. The electrodes show a linear response to changes in ferrocyanide concentration in large and very small (20 nl) volumes in vitro. The electrodes were used in an electrochemical microassay to determine tubular fluid-to-plasma ferrocyanide concentration ratios and nephron filtration rates with proximal micropuncture samples. The results show excellent agreement with paired determinations using [3H]inulin. In vivo proximal tubule perfusion experiments show a rapid linear response to changes in tubular fluid ferrocyanide concentration. These electrodes permit rapid quantitative measurements of ferrocyanide concentration and water transport in the proximal tubule and may be useful in other biological systems.