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， 关于共同释放的细胞基础仍然存在根本性的问题，这对它的生物学行为具有重要意义。 生理作用。在这个建议中，我们使用囊泡神经递质转运蛋白来阐明 参与协同释放的机制。在以前的工作中，我们发现中脑谷氨酸的共同释放 多巴胺神经元有两种不同的作用，一种是在充满多巴胺的囊泡中，另一种是作为独立的神经元。 信号了虽然对囊泡填充的影响需要囊泡单胺转运蛋白的共定位 VMAT 2和囊泡谷氨酸转运体VGLUT 2在相同的突触囊泡上，解剖学表明 也有一些分离，但生理后果尚不清楚。 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。释放 这两种递质在短时程抑制中的作用不同，依赖于不同的突触前Ca++通道。 突触囊泡属于对刺激反应不同的池，但这些差异已被归因于 外部因素如细胞骨架结合。我们现在表明，它们的组成也不同，因为 它们包含不同的发射器并释放具有不同性质的发射器。通过这一机制， 神经元可以将其输入反卷积为两个不同的输出。本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，决定了它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群体。具体地说， 我们将 1)通过对活神经元中的VMAT 2和VGLUT 2进行成像来比较单胺和谷氨酸的释放; 2)确定VMAT 2和VGLUT 2如何靶向不同的囊泡群体; 3)通过蛋白质组学表征单胺和谷氨酸SV的组成。 这些结果将提供有关神经元组织的基本信息，与共同释放直接相关。 其他细胞也会释放，所有神经元也会释放。

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.