NEURAL BASIS OF CIRCADIAN ORGANIZATION

几种海洋软体动物的孤立眼睛表达昼夜节律， 自发性视神经脉冲频率 在Bulla gouldiana， 最深入研究的制剂，眼节律产生 在视网膜基底（基底视网膜）的大约100个神经元中， 神经元）。 这些神经元彼此电耦合， 同步进行 最近完成的基底视网膜神经元实验 在分散的细胞培养物中以低密度铺板揭示昼夜节律 在膜电导中。 因此，昼夜节律产生出现 是单个神经元的特性， 组织水平。 拟议研究的总体目标是了解 生理节律产生的细胞机制， 夹带和表达。 实验针对七个 具体目标：1）单神经元昼夜节律振荡器模型将是 通过严格的测试来确定是否完全分离的神经元 保持节奏。 单细胞模型将由 比较分离的神经元与完整的神经元的昼夜节律特性， 视网膜。2)将对Ablassia的眼睛进行类似的分析。 3)跨膜钙信号在起搏器夹带中的作用 将在布拉和亚速尔群岛进行探索。 的时间轮廓， 钙信号和所涉及的钙通道的类型将被 鉴定4)产生昼夜节律的特定K+电导 将确定膜电位的节律， 磷酸化在调节K+电导的研究。5)的 膜电位变化的重要性和潜在的 将评估昼夜节律产生中的电导。6)的 传出FMRFamide投射在起搏调制中的作用 物业将进行探索。7)负责诱导的机制 相互耦合的眼起搏器之间的“相位跳变”将是 鉴定 该研究计划将采用细胞外，细胞内夏普 电极、全细胞和膜片钳电生理记录 程序和数字成像与荧光钙探针。 的 一种用于昼夜节律振荡器研究的单神经元模型的建立 提供了一个独特的机会来研究生物学的细胞基础， 时机 昼夜节律的产生、同步和调节 节律代表了神经生物学研究中的基本问题。

The isolated eyes of several marine mollusks express circadian rhythms in spontaneous optic nerve impulse frequency. In Bulla gouldiana, one of the most intensively studied preparations, the ocular rhythm is generated among approximately 100 neurons at the retinal base (basal retinal neurons). These neurons are electrically coupled to one another and fire in synchrony. Recently completed experiments with basal retinal neurons plated at low density in dispersed cell culture reveal circadian rhythms in membrane conductance. Therefore, circadian rhythm generation appears to be a property of individual neurons and does not require a tissue level of organization. The overall goal of the proposed research is to obtain an understanding of the cellular mechanisms underlying circadian rhythm generation, entrainment and expression. Experiments are directed towards seven specific aims: 1) The single neuron circadian oscillator model will be rigorously tested by determining whether completely isolated neurons remain rhythmic. The single cell model will then be developed by comparing the circadian properties of isolated neurons with the intact retina. 2) A similar analysis will be conducted for the eye of Aplysia. 3) The role of a transmembrane calcium signal for pacemaker entrainment will be explored in Bulla and in Aplysia. The temporal profile of the calcium signal and the type(s) of calcium channels involved will be identified. 4) The specific K+ conductances generating the circadian rhythm in membrane potential will be identified and the importance of phosphorylation in modulation of K+ conductances investigated. 5) The importance of changes in membrane potential and the underlying conductances in circadian rhythm generation will be evaluated. 6) The role of efferent FMRFamide projections in the modulation of pacemaker properties will be explored. 7) The mechanisms responsible for induction of "phase-jumps" between the mutually coupled ocular pacemaker will be identified. The research program will employ extracellular, intracellular sharp electrode, whole-cell and patch-clamp electrophysiological recording procedures and digital imaging with fluorescent calcium probes. The development of a single neuron model for circadian oscillator research provides a unique opportunity to study the cellular basis of biological timing. The generation, synchronization and modulation of circadian rhythms represent fundamental questions in neurobiological research.