Department of Chemistry , University of Cincinnati , 312 College Drive, 404 Crosley Tower , Cincinnati , Ohio 45221-0172 , United States.
Anal Chem. 2019 May 7;91(9):5987-5993. doi: 10.1021/acs.analchem.9b00450. Epub 2019 Apr 15.
Guanosine and adenosine are important neuromodulators in the brain and work in cooperation to mitigate the effects of stroke, traumatic injury, and other neurological events. Both purines can act on slow (minutes to hours) and rapid (milliseconds to seconds) time scales. A guanosine-adenosine interaction has been proposed in which guanosine modulates adenosine levels, and the two work together to control glutamate neurotransmission. Traditional methods to codetect purines, such as HPLC with microdialysis, are robust but lack the temporal resolution necessary to quantify release in real time. Fast-scan cyclic voltammetry (FSCV) has been used to detect guanosine and adenosine independently, but codetection has not been possible. Here, we developed a novel "scalene waveform" to codetect guanosine and adenosine with nanomolar limits of detection in real time with FSCV. The scalene waveform uses a slow rate (100 V/s) on the forward scan and the conventional rate (400 V/s) on the back scan; potentials go from -0.4 to 1.45 V and back to -0.4 V. The scan rates were optimized to increase the separation of the oxidative peaks for guanosine and adenosine. The temporal separation of the primary peaks was increased (4.6 ± 0.1)-fold at the scalene waveform compared to the traditional waveform. Both exogenously applied guanosine and adenosine and endogenous transient release were detected at the scalene waveform in rat-brain slices. We show the first method for codetecting guanosine and adenosine using FSCV, which can be used to study the guanosine-adenosine interaction and better understand their cooperative therapeutic effects.
鸟苷和腺苷是大脑中重要的神经调质，它们协同作用减轻中风、创伤和其他神经事件的影响。两种嘌呤都可以在慢（分钟到小时）和快（毫秒到秒）时间尺度上发挥作用。有人提出了一种鸟苷-腺苷相互作用，其中鸟苷调节腺苷水平，两者共同控制谷氨酸能神经传递。传统的同时检测嘌呤的方法，如微透析高效液相色谱法，虽然稳健，但缺乏实时定量释放所需的时间分辨率。快速扫描循环伏安法（FSCV）已被用于独立检测鸟苷和腺苷，但不能同时检测。在这里，我们开发了一种新的“斜三角波形”，可使用 FSCV 以纳摩尔级别的检测限实时同时检测鸟苷和腺苷。斜三角波形在正向扫描时使用慢速率（100 V/s），在反向扫描时使用常规速率（400 V/s）；电位从-0.4 到 1.45 V 再回到-0.4 V。优化了扫描速率以增加鸟苷和腺苷氧化峰的分离度。与传统波形相比，斜三角波形的主要峰的时间分离增加了（4.6±0.1）倍。在斜三角波形中，我们在大鼠脑切片中检测到了外源性应用的鸟苷和腺苷以及内源性瞬态释放。我们展示了使用 FSCV 同时检测鸟苷和腺苷的第一种方法，该方法可用于研究鸟苷-腺苷相互作用，更好地了解它们的协同治疗效果。
