ACTIVE PROPERTIES OF DENDRITES OF CA3 PYRAMIDAL NEURONS

CA3锥体神经元树突的活性特性

• 批准号: 2674530
• 负责人: Mark F Yeckel
• 金额: $ 2.36万
• 依托单位: BAYLOR COLLEGE OF MEDICINE
• 依托单位国家: 美国
• 财政年份: 1998
• 资助国家: 美国
• 起止时间: 1998-04-01 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/2674530
• 关键词: action potentials; brain mapping; calcium channel; dendrites; entorhinal cortex; fluorescent dye /probe; hippocampus; intercellular connection; laboratory rat; long term potentiation; mossy fiber; neural conduction; neural information processing; neural plasticity; pyramidal cells; sodium channel; synapses; voltage /patch clamp; voltage gated channel

Thus far my research efforts have focused on the functional relation between monosynaptic and multisynaptic excitation of the hippocampus by entorhinal afferents. Based on the results of these studies I have proposed a re-conceptualization of the intrinsic circuitry of the hippocampus monosynaptic entorhinal input to CA3 and CA1 provides feedforward modification of activity propagating through the trisynaptic pathway. The aim of this project is to investigate the cellular mechanisms that underlie observations showing that the nature and extent of the feedforward modification is dynamic, changing as a function of the pattern of entorhinal input. More specifically, I propose to test the hypothesis that synaptic activation of voltage-gated ion channels in CA3 pyramidal dendrites provide a fundamental mechanism by which these neurons integrate signals from multiple subsets of synapses such that occurs with direct, monosynaptic excitation by entorhinal afferents and indirect, disynaptic excitation via the mossy fiber projection. To accomplish this, I will use techniques recently developed in this laboratory including, dendrite- attached patch-clamp recording and high-speed fluorescent imaging. The specific aims are: l) Characterization of presumed voltage-dependent Ca2+ and Na+ channels in CA3 pyramidal dendrites, evoked by synaptic excitation and/or propagation of action potentials from the soma: 2) Characterization of the functional dynamics of these ion channels when excited by a specific subset of synapses, using different stimulation parameters, including those known to induce short- and long-term change in synaptic strength: and 3) Characterization of the functional dynamics of voltage-activated currents in CA3 dendrites under conditions that mimic physiological activity, such that might occur when multiple subsets of synaptic are excited, or when different patterns of action potentials are evoked in the soma. The possibility that these interactions might underlie the induction and expression of different forms of long-term potentiation (LTP) will also be examined.

到目前为止，我的研究工作集中在功能关系上 在海马的单突触和多突触激发之间 内河传入。根据这些研究的结果 提出了对固有电路的重新概念化 HAPPOCAMPS单突触到CA3和CA1提供 通过三突触传播的活动的馈送修改 路径。该项目的目的是研究细胞机制 该观察表明， 馈电修改是动态的，随着模式的变化而变化 内河输入。更具体地说，我建议检验假设 CA3锥体中电压门控离子通道的突触激活 树突提供了这些神经元整合的基本机制 来自多个突触子集的信号，以直接发生， 内河传入和间接，无突触的单突触激发 通过苔藓纤维投影激发。为此，我将使用 最近在该实验室开发的技术，包括树突状 - 附着的贴片钳记录和高速荧光成像。这 具体目的是： l）表征假定的电压依赖性Ca2+和Na+通道 CA3锥体树突，通过突触激发和/或传播引起 SOMA的动作电位：2）功能的表征 当特定子集激发这些离子通道的动力学 突触，使用不同的刺激参数，包括已知的参数 诱导突触强度的短期和长期变化：和3） 电压激活电流功能动力学的表征 在模仿生理活性的条件下，在CA3树突中 这可能会在多个突触激发多个子集时或 在躯体中引起了不同的动作电位模式。这 这些相互作用可能是归纳和 表达不同形式的长期增强（LTP）也将是 检查。

项目成果

Spatial distribution of potentiated synapses in hippocampus: dependence on cellular mechanisms and network properties.

海马增强突触的空间分布：依赖于细胞机制和网络特性。

• DOI: 10.1523/jneurosci.18-01-00438.1998
• 发表时间: 1998
• 期刊: The Journal of neuroscience : the official journal of the Society for Neuroscience
• 作者: Yeckel,MF;Berger,TW
• 通讯作者: Berger,TW

Photolysis of postsynaptic caged Ca2+ can potentiate and depress mossy fiber synaptic responses in rat hippocampal CA3 pyramidal neurons.

• DOI: 10.1152/jn.01073.2003
• 发表时间: 2004-04
• 期刊: Journal of neurophysiology
• 影响因子: 2.5
• 作者: Jun Wang;M. Yeckel;D. Johnston;R. Zucker