Melatonin (MT) is an important electroactive hormone that regulates different physiological actions in the brain, ranging from circadian clock to neurodegeneration. An impressive number of publications have highlighted the effectiveness of MT treatments in different types of sleep and neurological disorders, including Alzheimer's and Parkinson's disease. The ability to detect MT in different regions of the brain would provide further insights into the physiological roles and therapeutic effects of MT. While multiple electrochemical methods have been used to detect MT in biological samples, monitoring MT in the brain of live animals has not been demonstrated. Here, we optimized a square wave voltammetry (SWV) electroanalytical method to evaluate the MT detection performance at CFEs in vitro and in vivo. SWV was able to sensitively detect the MT oxidation peak at 0.7 V, and discriminate MT from most common interferents in vitro. More importantly, using the optimized SWV, CFEs successfully detected and reliably quantified MT concentrations in the visual cortex of anesthetized mice after intraperitoneal injections of different MT doses, offering stable MT signals for up to 40 minutes. To the best of our knowledge, this is the first electrochemical measurement of exogenously administered MT in vivo. This electrochemical MT sensing technique will provide a powerful tool for further understanding MT's action in the brain.

中文翻译：

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大脑中外源性褪黑激素的电化学检测。

褪黑激素 (MT) 是一种重要的电活性激素，可调节大脑中的不同生理活动，从生物钟到神经退行性疾病。大量出版物强调了 MT 治疗对不同类型的睡眠和神经系统疾病（包括阿尔茨海默病和帕金森病）的有效性。检测大脑不同区域的 MT 的能力将有助于进一步了解 MT 的生理作用和治疗效果。虽然多种电化学方法已被用于检测生物样本中的 MT，但监测活体动物大脑中的 MT 尚未得到证实。在这里，我们优化了方波伏安法 (SWV) 电分析方法来评估体外和体内 CFE 的 MT 检测性能。SWV 能够灵敏地检测 0.7 V 处的 MT 氧化峰，并在体外将 MT 与最常见的干扰物区分开来。更重要的是，使用优化的 SWV，CFE 成功检测并可靠地量化了腹腔注射不同 MT 剂量后麻醉小鼠视觉皮层的 MT 浓度，提供长达 40 分钟的稳定 MT 信号。据我们所知，这是首次对体内外源性 MT 进行电化学测量。这种电化学 MT 传感技术将为进一步了解 MT 在大脑中的作用提供强大的工具。