In vivo chemical monitoring using capillary separations

描述（由申请人提供）：神经元通过释放神经递质进行交流，神经递质通过与受体相互作用扩散到邻近细胞而产生作用。细胞外空间内神经递质水平的变化是神经元之间传递信息的指示。在体内测量这些浓度动态是了解神经传递并最终了解大脑、脑部疾病和行为的重要手段。目前监测体内神经递质的方法包括传感器或采样技术，以及分数分析。传感器功能强大，但一次只能测量一种化合物。此外，仅为100多种神经递质中的少数几种开发了传感器。采样方法受限于几分钟的时间分辨率，而神经递质浓度在第二个时间尺度上发生变化。此外，大尺寸的采样探针妨碍了对许多大脑区域的测量。这项工作的目的是开发监测许多神经递质与生理和行为相关的时间和空间分辨率的方法。在这个建议中，微制备电泳系统将与微透析探针相结合，以实现胺类神经递质的高分辨率监测。将开发一种新型微采样探针，其空间分辨率比微透析提高500倍以上。神经肽分析将通过开发采样探针提高收集效率而得到改进。此外，通过将微型毛细管色谱柱与质谱连接，可以提高神经肽测量的灵敏度。这些方法将与几个神经科学小组合作，用于研究：1)乙醇成瘾中的牛磺酸/多巴胺神经传递，2)亨廷顿氏病小鼠中谷氨酸/抗坏血酸的相互作用，3)脑啡肽酶抑制剂（一种新型抗抑郁药）的体内神经化学作用，以及4)睡眠中的神经化学信号。

DESCRIPTION (provided by applicant): Neurons communicate by releasing neurotransmitters, which diffuse to neighboring cells causing an effect by interacting with a receptor. Changes in neurotransmitter levels within the extra cellular space are an indication of the messages sent between neurons. Measurement of these concentration dynamics in vivo is an important means of understanding neurotransmission and ultimately the brain, brain diseases, and behavior. Present methods for monitoring neurotransmitters in vivo involve sensors or sampling techniques coupled with analysis of fractions. Sensors are powerful yet limited to measuring one compound at a time. Furthermore, sensors for just a few of the over 100 neurotransmitters have been developed. Sampling approaches are limited by temporal resolution of a few minutes whereas neurotransmitter concentrations change on the second time scale. In addition, the large size of sampling probes precludes measurement in many brain regions. The objective of this work is to develop methods of monitoring many neurotransmitters with physiologically and behaviorally relevant temporal and spatial resolution. In this proposal a microfabricated electrophoresis system will be coupled to a microdialysis probe to accomplish high-resolution monitoring of amine neurotransmitters. A novel microsampling probe with over 500-fold better spatial resolution than microdialysis will be developed. Neuropeptide analysis will be improved by developing sampling probes with improved collection efficiencies. In addition, improved sensitivity for neuropeptide measurements will be obtained by interfacing miniaturized capillary chromatography columns to mass spectrometry. The methods will be applied by collaborating with several neuroscience groups for investigation of: 1) taurine/dopamine neurotransmission in ethanol addiction, 2) glutamate/ascorbate interactions in mice engineered to develop Huntington's disease, 3) the in vivo neurochemical effects of an enkephalinase inhibitor (a novel anti-depressant), and 4) the neurochemical signals in sleep.