Real-time telemetry monitoring of oxygen in the central complex of freely-walking Gromphadorhina portentosa

A new telemetric system for the electrochemical monitoring of dissolved oxygen is showed. The device, connected with two amperometric sensors, has been successfully applied to the wireless detection of the extracellular oxygen in the central complex of freely-walking Gromphadorhina portentosa. The unit was composed of a potentiostat, a two-channel sensor conditioning circuit, a microprocessor module, and a wireless serial transceiver. The amperometric signals were digitalized and sent to a notebook using a 2.4 GHz transceiver while a serial-to-USB converter was connected to a second transceiver for completing the communication bridge. The software, running on the laptop, allowed to save and graph the oxygen signals. The electronics showed excellent stability and the acquired data was linear in a range comprised between 0 and -165 nA, covering the entire range of oxygen concentrations. A series of experiments were performed to explore the dynamics of dissolved oxygen by exposing the animals to different gases (nitrogen, oxygen and carbon dioxide), to low temperature and anesthetic agents (chloroform and triethylamine). The resulting data are in agreement with previous O2 changes recorded in the brain of awake rats and mice. The proposed system, based on simple and inexpensive components, can constitute a new experimental model for the exploration of central complex neurochemistry and it can also work with oxidizing sensors and amperometric biosensors.本文展示了一款用于溶解氧电化学监测的新型遥测系统。该装置搭载两枚安培传感器（amperometric sensor），已成功应用于自由活动的发声蟑螂（Gromphadorhina portentosa）中央复合体的细胞外氧无线检测。该系统单元由恒电位仪（potentiostat）、双通道传感器调理电路、微处理器模块及无线串行收发器（wireless serial transceiver）组成。安培信号经数字化处理后，通过2.4 GHz收发器传输至笔记本电脑；同时，串行转USB转换器（serial-to-USB converter）连接至第二台收发器以搭建完整通信链路。运行于笔记本电脑的配套软件可对氧信号进行存储与绘图展示。该电子系统展现出优异的稳定性，采集数据在0至-165纳安（nA）范围内呈线性关系，覆盖全部氧浓度区间。研究团队通过将受试动物暴露于不同气体（氮气、氧气与二氧化碳）、低温环境以及麻醉剂（氯仿与三乙胺）中，开展一系列实验以探究溶解氧的动态变化过程。实验所得数据与此前清醒大鼠及小鼠脑内氧浓度变化的研究结果一致。本系统基于简单且低成本的元器件搭建，可作为探索中央复合体神经化学的新型实验模型，同时也可适配氧化传感器与安培型生物传感器。