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通信，神经递质扩散到邻近细胞，通过与受体相互作用产生效应。细胞外空间内神经递质水平的变化是神经元之间发送信息的指示。在体内测量这些浓度动态是理解神经传递并最终理解大脑、大脑疾病和行为的重要手段。目前用于监测体内神经递质的方法涉及传感器或采样技术与组分分析相结合。传感器功能强大，但每次只能测量一种化合物。此外，已经开发出了100多种神经递质中的几种的传感器。采样方法受到几分钟的时间分辨率的限制，而神经递质浓度在第二时间尺度上变化。此外，采样探针的大尺寸排除了在许多大脑区域中的测量。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。在这个提议中，一个微制造的电泳系统将耦合到一个微透析探针，以实现高分辨率的监测胺神经递质。将开发一种新型的微取样探针，其空间分辨率比微透析高500倍以上。神经肽分析将通过开发具有改进的收集效率的采样探针来改进。此外，神经肽测量的灵敏度将通过将小型化毛细管色谱柱与质谱法连接而得到提高。这些方法将通过与几个神经科学小组合作来应用，以研究：1）乙醇成瘾中的牛磺酸/多巴胺神经传递，2）被工程改造为发展亨廷顿病的小鼠中的谷氨酸/抗坏血酸相互作用，3）脑啡肽酶抑制剂（一种新型抗亨廷顿病剂）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.