Neurotransmitter Corelease

越来越多的证据表明，许多神经元释放两种经典的神经递质，但 关于共释放的细胞基础的基本问题仍然存在，这对其 生理作用。在这个方案中，我们使用囊泡神经递质转运体来阐明 参与共释放的机制。在以前的工作中，我们证明了谷氨酸通过中脑共同释放 多巴胺神经元有两种截然不同的作用，一种是在充满多巴胺的囊泡中，另一种是作为一个独立的 信号。尽管对囊泡充盈的影响需要囊泡单胺转运体的共同定位 解剖表明，VMAT2和囊泡谷氨酸转运体VGLUT2位于相同的突触小泡上 也有一些种族隔离，但其生理后果尚不清楚。 我们现在发现，多巴胺神经元释放不同性质的谷氨酸和多巴胺。发布 这两种递质在短期抑郁时不同，并依赖于不同的突触前钙通道。 突触小泡属于对刺激反应不同的池，但这些差异被归因于 与细胞骨架联合等外在因素有关。我们现在说明它们在组成上也不同，因为 它们含有不同的发射器，并以不同的性质释放它们。通过这一机制，单一的 神经元可以将其输入去卷积为两个不同的输出。这个项目的长期目标是阐明 神经递质共同释放的细胞和分子基础，并决定其在信息处理中的作用。 该策略是使用囊泡转运蛋白来表征不同的囊泡种群。具体来说， 我们会的 1)通过成像VMAT2和VGLUT2比较活体神经元中单胺和谷氨酸的释放； 2)确定VMAT2和VGLUT2如何靶向不同的囊泡种群； 3)用蛋白质组学方法研究单胺和谷氨酸SVS的组成。 结果将提供有关神经元组织的基本信息，与共释放直接相关 由其他细胞释放，也由所有神经元释放。

Accumulating evidence shows that many neurons release two classical neurotransmitters, but fundamental questions remain about the cellular basis for corelease, with important implications for its physiological role. In this proposal, we use the vesicular neurotransmitter transporters to elucidate the mechanisms involved in corelease. In previous work, we showed that glutamate corelease by midbrain dopamine neurons serves two distinct roles, one in vesicle filling with dopamine and the other as an independent signal. Although the effects on vesicle filling require colocalization of the vesicular monoamine transporter VMAT2 and vesicular glutamate transporter VGLUT2 on the same synaptic vesicles, anatomy has suggested some segregation as well, but with unclear physiological consequences. We now find that dopamine neurons release glutamate and dopamine with different properties. Release of the two transmitters differs in short-term depression and depends on different presynaptic Ca++ channels. Synaptic vesicles belong to pools that differ in response to stimulation but these differences have been attributed to extrinsic factors such as cytoskeletal association. We now show that they also differ in composition because they contain different transmitters and release them with different properties. Through this mechanism, a single neuron can deconvolve its input into two distinct outputs. The long-term objectives of this project are to elucidate the cellular and molecular basis for neurotransmitter corelease and determine its role in information processing. The strategy is to use the vesicular transporters to characterize the different vesicle populations. Specifically, we will 1) compare monoamine and glutamate release by imaging VMAT2 and VGLUT2 in live neurons; 2) determine how VMAT2 and VGLUT2 target to distinct vesicle populations; 3) characterize the composition of monoamine and glutamate SVs by proteomics. The results will provide basic information about the organization of neurons, with direct relevance for corelease by other cells, but also for release by all neurons.