Electrical Signaling in a Circadian Pacemaker Circuit

描述（由申请人提供）：虽然对模式生物果蝇的昼夜节律分子钟的核心成分和运作及其神经解剖学位置了解很多，但对这种昼夜节律分子钟如何与起搏器神经元中的电信号相互作用知之甚少。昼夜节律分子钟如何控制起搏器神经元电活动和突触输出，从而最终控制动物行为，这是一个悬而未决的问题。通过膜片钳和成体全脑神经元成像的直接生理分析，以及果蝇昼夜节律起搏器神经元中修饰离子通道的转基因表达，研究起搏器神经元电信号与昼夜节律分子钟和动物行为之间的生理相互作用。转基因策略已经被设计出来：(1)电沉默起搏器神经元和(2)电过度激活起搏器神经元。每一种对起搏器神经元电活动的操纵都会导致昼夜节律行为的显著变化。

DESCRIPTION (provided by applicant): While much is known about the core components and the operation of the circadian molecular clock and its neuroanatomical location in the model organism Drosophila, very little is known about how this circadian molecular clock interacts with electrical signaling in the pacemaker neurons. It is an open questions as to how circadian molecular clock controls pacemaker neuronal electrical activity and synaptic output that ultimately controls animal behavior. The physiological interactions between pacemaker neuron electrical signaling and the circadian molecular clock and animal behavior will be studied by direct physiological analysis using patch clamp and imaging of adult whole brain neurons as well as transgenic expression of modified ion channels in the circadian pacemaker neurons of Drosophila. Transgenic strategies have been devised to (1) electrically silence pacemaker neurons and (2) electrically hyper-excite pacemaker neurons. Each of these manipulations of pacemaker neuronal electrical activity causes striking changes in circadian behavior. The Specific Aims are to: (1) Map the functional subsets of the pacemaker neural circuit by electrical silencing, neurotransmitter markers, and immunocytochemistry; (2) Determine the mechanism of electrically hyper-excitation induced rhythm splitting and NaChBac expression's functional rescue of the electrically silenced pacemaker neural circuit; (3) Map the electrophysiological properties of wild-type and modified channel-expressing Drosophila pacemakers. These studies will elucidate the physiological mechanisms that determine circadian behavior in a well studied model organism. Ultimately, this work may provide powerful new tools for the general study of neural circuits and novel molecular-genetic strategies for studying and treating human diseases of aberrant cellular electrical excitability.