In vivo chemical monitoring using capillary separations

描述(申请人提供)：神经元通过释放神经递质进行交流，神经递质扩散到邻近细胞，通过与受体相互作用而产生影响。细胞外空间内神经递质水平的变化表明神经元之间传递的信息。在体内测量这些浓度动态是了解神经传递以及最终了解大脑、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，以及对组份的分析。传感器功能强大，但仅限于一次测量一种化合物。此外，仅针对100多种神经递质中的几种开发了传感器。采样方法受到几分钟时间分辨率的限制，而神经递质浓度在第二时间尺度上变化。此外，取样探头的大尺寸排除了在许多大脑区域进行测量的可能性。这项工作的目标是开发具有生理和行为相关的时间和空间分辨率的许多神经递质的监测方法。在这项提议中，一个微制的电泳仪将被连接到一个微透析探头上，以完成对胺类神经递质的高分辨率监测。一种新型的微采样探头将被开发出来，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更高收集效率的采样探针来改进。此外，通过将微型毛细管色谱柱连接到质谱柱，将提高神经肽测量的灵敏度。这些方法将通过与几个神经科学小组的合作来应用，以研究：1)酒精成瘾中的牛磺酸/多巴胺神经传递，2)谷氨酸/抗坏血酸在亨廷顿病小鼠中的相互作用，3)脑啡肽酶抑制剂(一种新型抗抑郁药)在体内的神经化学效应，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.