NEURAL BASIS OF CIRCADIAN ORGANIZATION

几种海洋软体动物孤立的眼睛表现出昼夜节律 自发视神经脉冲频率。在Bulla Gouldiana， 研究最深入的准备工作是产生眼球节律 在视网膜底部(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，并发出信号 同步性。最近完成的视网膜基底神经元实验 分散细胞培养中低密度培养显示昼夜节律 在膜电导中。因此，昼夜节律的产生应运而生 是单个神经元的属性，不需要组织 组织层级。 拟议研究的总体目标是了解 昼夜节律产生的细胞机制， 夹带和表达。实验针对的是七个 具体目标：1)单神经元昼夜节律振荡器模型 通过确定完全分离的神经元是否 保持节奏。然后，单细胞模型将由 分离神经元与完整神经元昼夜节律特性的比较 视网膜。2)对海兔的眼睛也进行了类似的分析。 3)跨膜钙信号在起搏器夹带中的作用 将在Bulla和Aplysia进行探索。时间分布的时间分布 钙信号和涉及的钙通道类型(S)将 已确认身份。4)产生昼夜节律的特定K+电导 膜电位的节律将被识别，并且 研究了磷酸化在调节K+电导中的作用。5) 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) 传出FMRFamide投射在起搏器调节中的作用 本课程将探索各种属性。7)诱导的机制 相互耦合的眼部起搏器之间的“相位跳跃”将是 已确认身份。 该研究计划将采用细胞外、细胞内的夏普 电极、全细胞和膜片钳电生理记录 程序和使用荧光钙探针的数字成像。这个 用于昼夜节律振荡器研究的单神经元模型的发展 为研究生物的细胞基础提供了一个独特的机会 时机到了。昼夜节律的产生、同步和调制 节律代表了神经生物学研究的基本问题。

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.