CELLULAR MECHANISMS OF PRESYNAPTIC INHIBITION

递质释放的调节是中枢神经系统的组成部分 (CNS)功能因此，了解这种现象对于 了解脊椎动物中枢神经系统，其中突触前末梢是 大部分都很小，难以接近这个项目的目标是调查 氨基酸受体介导的递质释放调节 七鳃鳗脊髓中的突触前末梢。该制备使得 使用成像和电生理学对终端进行无与伦比的访问。 轴突电压操纵性通道和突触前终末的特性 将研究;特别是电压操作的Ca 2+通道。 激活Ca 2+通道，同时记录细胞内Ca 2 + 通过成像加载到细胞中的Ca 2+敏感性荧光染料来浓缩。 轴突通过记录电极，将使其定位。 电压阶跃范例和药理学试剂特异性。 Ca 2+通道将能够识别突触前的通道 终端在这些实验的同时，对装载染料的配对的 突触后胞体将显示Ca 2+之间的空间关系 通道的终端和网站的突触接触。 本表的配对细胞记录将用于研究 氨基酸应用对突触传递的影响。应用 对γ-氨基丁酸（GABA）受体有活性的试剂将允许 详细分析了GABA受体的位置和亚型， 突触传递的调节。GABA作用的观察 电压激活的Ca 2+进入突触前的受体激活 药物对第二信使功能影响 终端的内部将用于研究细胞机制 GABA受体的激活通过其被转导。记录技术 还将进行电生理学和显微荧光测定， 研究谷氨酸代谢型受体作用方式和部位 （mGluRs）在七鳃鳗脊髓突触前和突触后元件中的表达 线. mGluR和GABA受体激活之间的共同机制将是 寻求控制发射器释放，以及机制 对每一类受体都有特异性。 突触前GABA受体和mGluRs在运动调节中的作用 将对产出进行调查。的激活或阻断的影响， 将测试脊髓运动输出上的这些受体。此外，Ca 2 + 轴突成像将用于研究相位和时间依赖性 在脊髓中不同位置的Ca 2+内流的变化。因此 将有可能将突触前受体的细胞效应 激活到脊柱运动系统的控制。

Modulation of transmitter release is integral to central nervous system (CNS) function. Understanding this phenomenon is, thus, important in understanding the vertebrate CNS, in which presynaptic terminals are mostly small and inaccessible. The goal of this project is to investigate amino acid receptor-mediated modulation of transmitter release from presynaptic terminals in the lamprey spinal cord. This preparation enables unequalled access to the terminal using imaging and electrophysiology. Properties of axonal voltage operated channels and presynaptic terminals will be investigated; particularly voltage operated Ca2+ channels. Activation of Ca2+ channels, while recording intracellular Ca2+ concentration by imaging Ca2+-sensitive fluorescent dye loaded into the axon through the recording electrode, will enable their localization. Voltage Step paradigms and pharmacological agents specific to.subtypes of Ca2+ channel will enable identification of channels at the presynaptic terminal. Concurrent to these experiments imaging of dye loaded paired postsynaptic somata will demonstrate spatial relationships between Ca2+ channels in the terminal and the site of synaptic contacts. Paired cell recordings of this form will be used to investigate the effects of amino acid application upon synaptic transmission. Application of reagents active at gamma aminobutyric acid (GABA) receptors will allow a detailed analysis of location and subtypes of GABA receptors involved in modulation of synaptic transmission. Observation of the effects of GABA receptor activation on voltage-activated Ca2+ entry to the presynaptic terminal and interference of 2nd messenger function by drug application to the interior of the terminal will be used to study the cellular mechanisms by which GABA receptor activation is transduced. Techniques of recording electrophysiologically and microfluorimetrically will also be pursued to investigate modes and sites of action of glutamate metabotropic receptors (mGluRs) in the pre- and post-synaptic elements of the lamprey spinal cord. Common mechanisms between mGluR and GABA receptor activation will be sought in the control of transmitter release, as well as mechanisms specific to each class of receptor. The roles of presynaptic GABA receptors and mGluRs in modulating motor output will be investigated. The effect of the activation or blockade of these receptors on spinal motor output will be tested. Additionally Ca2+ imaging of the axons will be used to investigate phase- and time-dependent changes in Ca2+ entry at different locations in the spinal cord. Thus it will be possible to relate cellular effects of presynaptic receptor activation to the control of the spinal motor system.