ELECTROPHYSIOLOGY OF PRESYNAPTIC NERVE TERMINALS

神经生物学中的一个基本问题是突触前的兴奋性 神经末梢，这是突触释放的关键 神经递质。调节终端兴奋性的因素有 人们对此知之甚少。这是由于脊椎动物的体型极小。 神经末梢，这使得细胞内记录不可能 获取。似乎许多经典和多肽类神经递质，如 以及一氧化氮和一氧化碳，都可以影响电能 突触前终末的特性。然而，现有的证据表明 这种影响很大程度上是间接的，取决于突触后的变化 对释放的发射机的响应。 在这项建议中，将使用一个独特的模型系统来研究 脊椎动物神经末梢的电学特性。副交感神经 雏鸟纤毛含有形成杯状突触前神经末梢- 纤毛神经元上有类似或帽状的末梢。我们已经做出了 这些神经末梢的细胞内记录，并找到证据 上的许多离子通道和神经递质受体 终点站。将解决以下基本问题，即 脊椎动物神经末梢上存在离子通道，离子通道的作用是什么？ 它们在调节终端区的膜电位方面起作用吗？ 突触前神经递质受体如何改变神经元的兴奋性 神经末梢？神经递质受体能否定位于突触前 神经末梢在功能上偶联到不同的离子通道 相同的受体位于同一神经元的胞体和树突上吗？ 将进行细胞内(锐化)和全细胞膜片钳记录 来自完整睫状神经节的帽状终末。使用 脑片准备，类似的记录将从神经元 雏鸡外侧Edinger-Westphal核，自大终末在 睫状神经节起源于该终末的细胞体 受体和类似的体细胞/树突状受体 神经元。阿片类药物和速激肽都将用于这些研究， 作为这两类神经肽的受体，Edinger上存在- Westphal SoMAS和帽状终端。特别感兴趣的阿姆 和增量阿片受体，因为我们的初步结果表明，这些 受体连接到终端区的不同离子通道 而不是在体细胞区域。产生这些不同的机制 将使用各种具有抑制作用的试剂来检查反应 或对G蛋白介导的细胞内途径的刺激作用。 这项提案寻求获得有关以下因素的新信息 改变突触前神经末梢的兴奋性。模型系统 为解决以下几个基本问题提供了独特的机会 神经生物学中与细胞功能直接相关的问题 突触前神经末梢分布于整个神经系统。 可能存在正常突触前终末兴奋性的改变 在许多神经疾病中，包括癫痫和阿尔茨海默氏症 疾病。

A fundamental problem in neurobiology is the excitability of presynaptic nerve terminals, which is critical for synaptic release of neurotransmitter. The factors regulating excitability of terminals are poorly understood. This is due to the extremely small size of vertebrate nerve terminals, which make intracellular recordings impossible to obtain. It appears that many classical and peptide neurotransmitter, as well as nitric oxide and carbon monoxide, can influence the electrical properties of presynaptic terminals. However, the existing evidence for such influence is largely indirect, relying on changes in postsynaptic responses to released transmitter. In this proposal, a unique model system will be used to study the electrical properties of vertebrate nerve terminals. The parasympathetic chick ciliary contains "giant" presynaptic nerve terminal that form cup- like or calyciform endings on ciliary neurons. We have made intracellular recordings from these nerve terminals, and find evidence for a number of ion channels and neurotransmitter receptors on the terminals. The following fundamental questions will be addressed, Which ion channels are present on vertebrate nerve terminals, and what role do they play in regulating the membrane potential of the terminal region? How do presynaptic neurotransmitter receptors alter the excitability of nerve terminal? Can neurotransmitter receptors located on presynaptic nerve terminals be functionally coupled to different ion channels than are identical receptors situated on the same neuron's soma and dendrites? Intracellular (sharp) and whole-cell patch clamp recording will be made from calyciform terminals in intact ciliary ganglia in vitro. Using a brain slice preparation, similar recordings will be made from neurons in the chick lateral Edinger-Westphal nucleus, since the large terminal in the ciliary ganglion originate from cell bodies in this terminal receptors and similar somatic/dendritic receptors on the same class of neurons. Both opioids and tachykinins will be used for these studies, as receptors for both classes of neuropeptides are present on Edinger- Westphal somas and on calyciform terminals. OF particular interest ar mu and delta opioid receptors, since our initial results indicate that these receptors are coupled to different ion channels in the terminal region than in the somatic region. The mechanisms producing these disparate responses will be examined using a variety of agents that have inhibitory or stimulatory effects on G-protein-mediated intracellular pathways. This proposal seeks to obtain new information regarding factors that can alter the excitability of presynaptic nerve terminal. The model system to be used provides a unique opportunity to address several fundamental questions in neurobiology that are directly relevant to the function of presynaptic nerve terminals located throughout the nervous system. Alterations in normal presynaptic terminal excitability may be present in a number of neurological disease, including epilepsy and Alzheimer's disease.