Presynaptic Mechanisms of Neurotransmission in NTS

心血管系统的节拍调节依赖于完整的压力感受器反射。这条反射弧线首先 孤束核(NTS)中的突触，释放谷氨酸。压力反射功能是 常见威胁生命的疾病状态：高血压、休克和心力衰竭。在.工作 大的、可接近的中枢神经系统终末表明，突触前控制谷氨酸释放涉及离子 调节囊泡胞吐的通道和第二信使系统。谷氨酸的调节因地而异 神经元，但对其机制知之甚少。调节心血管和心脏的反射通路 呼吸系统依赖于脑干神经元，这些反射是由脑神经初级启动的。 孤束核(NTS)内的传入纤维。对于初级传入是如何传入的知之甚少。 举止要居中。这些航站楼的面积很小，难以直接调查。我们有 开发了允许从NTS的单个神经末梢进行膜片钳记录的方法。我们的研究计划 将使用这些方法来解决我们的驱动假设，即NTS中重要的监管机制 取决于传入神经元的身份。我们的初步工作表明，NTS神经元提供了一个 独一无二的机会是因为：1.我们可以直接可视化、识别、刺激和电生理记录 从单个神经末梢，NTS接受药理上可区分的传入终末，形成 已知起源于分子上不同的外周神经元的亚类，3.这些终末的亚集可以是 标记为提供指向功能不同的传入的链接。我们的计划包括两个实验室的努力， 适用于这一问题的互补专业知识。我们将使用直接贴片记录和刺激单次 终末，以及成像，以研究频率依赖性突触抑制和 多肽对谷氨酸释放的调节作用。这项工作充分利用了初级传入终末的标记 以区分不同的亚类(TRPV1和P2X3；分别为C型和A型传入终末)。 具体目标涉及A型和C型钠、钾和钙通道的差异表达 脑传入突触末梢加上新的突触前调节突触的机制的存在 钙质裂开。不同的传入神经末梢亚类也将根据它们的 多肽对谷氨酸释放和调节的控制。

Beat to beat regulation of the cardiovascular system depends on an intact baroreflex. This reflex arc first synapses in the nucleus tractus solitarius (NTS) where glutamate is released. Baroreflex function is compromised in common life threatening disease states: hypertension, shock, and heart failure. Work in large, accessible CNS terminals suggests that the presynaptic control of glutamate release involves ion channels and 2nd messenger systems that regulate vesicle exocytosis. Glutamate regulation differs across neurons, but the mechanisms are poorly understood. Reflex pathways regulating the cardiovascular and respiratory systems depend on brainstem neurons and these reflexes are initiated by cranial nerve primary afferents acting within the nucleus tractus solitarius (NTS). Little is known about how primary afferents behave centrally. The small size of these terminals has made direct investigation difficult. We have developed methods to permit patch clamp recording from single nerve terminals in NTS. Our Research Plan will use these methods to address our driving hypothesis that important mechanisms of regulation in NTS depend on the identity of the afferent neuron. Our Preliminary Work demonstrates that NTS neurons offer a unique opportunity because: 1. we can directly visualize, identify, stimulate and electrophysiologically record from single nerve terminals, 2. NTS receives pharmacologically distinguishable afferent terminals that form subclasses known to arise from molecularly distinct peripheral neurons, 3. Subsets of these terminals can be labeled to provide links to functionally distinct afferents. Our Plan encompasses the efforts of two labs with complementary expertise suited to this problem. We will use direct patch recording and stimulation of single terminals, as well as imaging, to study the mechanism of frequency dependent synaptic depression and peptide modulation of glutamate release. The work capitalizes on using markers of primary afferent terminals to distinguish the various sub classes (TRPV1 and P2X3; C- and A-type afferent terminals, respectively). Specific Aims concern differential sodium, potassium and calcium channel expression across A- and C-type cranial afferent synaptic terminals plus the presence of new presynaptic mechanisms regulating synaptic cleft calcium. The different sub classes of afferent nerve terminal will be also be compared in terms of their control of glutamate release and modulation by peptides.