INTERFERENCE BY PH AND CA2+ IONS DURING MEASUREMENTS OF CATECHOLAMINE RELEASE IN SLICES OF RAT AMYGDALA WITH FAST-SCAN CYCLIC VOLTAMMETRY
INTERFERENCE BY PH AND CA2+ IONS DURING MEASUREMENTS OF CATECHOLAMINE RELEASE IN SLICES OF RAT AMYGDALA WITH FAST-SCAN CYCLIC VOLTAMMETRY
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DOI：
10.1016/0165-0270(94)90048-5
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发表时间：
1994-04-01
影响因子：
3
通讯作者：
WIGHTMAN, RM
中科院分区：
文献类型：
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作者：
JONES, SR;MICKELSON, GE;WIGHTMAN, RM
采用碳纤维微电极快速扫描循环伏安法（FSCV）研究了电刺激大鼠基底外侧杏仁核脑片引起的儿茶酚胺释放和摄取。杏仁核比纹状体含有更少的儿茶酚胺，并且观察到的释放也相应地更小。需要长时间的刺激序列，以获得一个良好的解决在基底外侧杏仁核的浓度变化。在这些条件下的儿茶酚胺伏安检测是复杂的干扰，从两个细胞外离子，H+和Ca 2+。离子选择性微电极与碳纤维微电极一起用于监测pH和Ca 2+。的pH值变化的幅度与刺激长度，并遵循的模式，一个简短的碱性转变，然后由一个较长的酸性转变。细胞外Ca 2+浓度在刺激过程中下降，并在刺激结束后相当迅速地恢复到基线。因为不可能使用伏安图中的信息来解释所有的离子干扰，所以采用了其他策略。暴露杏仁核切片左旋多巴或DA增加电诱发释放的儿茶酚胺，但效果是短暂的，和摄取率下降，在继续暴露于这些代理商。去除干扰的最成功的方法是减去切片暴露于儿茶酚胺消耗剂Ro 4-1284后获得的响应。该试剂消除了儿茶酚胺反应，但似乎不改变离子变化。
Fast-scan cyclic voltammetry (FSCV) at carbon-fiber microelectrodes was used to investigate catecholamine release and uptake induced by local electrical stimulation of rat brain slices containing the basolateral amygdaloid nucleus. The amygdala contains less catecholamine than the striatum, and the observed release is proportionately smaller. Stimulus trains of long duration were required to obtain a well-resolved concentration change in the basolateral amygdala. Voltammetric detection of catecholamines under these conditions was complicated by interference from two extracellular ions, H+ and Ca2+. Ion-selective microelectrodes were used in conjunction with carbon-fiber microelectrodes to monitor pH and Ca2+. The magnitude of-the pH changes was correlated with stimulation length and followed the pattern of a brief alkaline shift followed by a longer acidic shift. Extracellular Ca2+ concentration decreased during stimulation and returned fairly rapidly to baseline after the stimulation was over. Because it was not possible to account for all of the ionic interferences using information in the voltammograms, other strategies were employed. Exposure of amygdala slices to L-DOPA or DA increased electrically evoked release of catecholamine, but the effect was transient, and uptake rates decreased during continued exposure to these agents. The most successful approach to remove the interferences was to subtract the response obtained after exposure of the slice to the catecholamine depleter, Ro 4-1284. This agent eliminates the catecholamine response but does not appear to alter the ionic changes.