Regulation of the striatal network by glutamate and acetylcholine co-transmission.

神经元通过电化学信号进行交流。化学信使或神经递质在依赖钙释放之前积聚在突触小泡(SV)内。谷氨酸(Glut)是大脑中主要的兴奋性递质，通过称为VGLUT1-3的囊泡转运蛋白集中在SV内。我们的团队做出了令人惊讶的发现，VGLUT3是由神经元使用谷氨酸以外的其他神经递质表达的。VGLUT3目前被所有纹状体胆碱能中间神经元(也称为张力活性神经元或TANS)所使用。因此，TANS与乙酰胆碱(ACh)和Glut一起发出信号。ACh/Glut共传播的后果最近开始被调查。例如，我们证实了VGLUT3基因缺失的小鼠是过度活跃的，对可卡因更敏感。这主要是由于伏隔核多巴胺信号在缺乏VGLUT3的情况下增加所致。有趣的是，通过特异性消融囊泡ACh转运体(Vacht)来沉默TAN中的ACh信号具有相反的效果。因此，双重ACh/GLUT传递为TANS提供了纹状体网络的复杂调节特性。 我们最近观察到Vacht或VGLUT3在TANS中被归类于不同的SVS群体。我们建议的目的是为了更好地了解Vacht或VGLUT3在TANS中泡状分选的分子机制。这将有助于识别参与纹状体网络调控的原始分子靶点。特别是，不同类型的钙通道(L通道、N通道、P通道和Q通道)对神经递质的释放起着关键的调节作用。这些钙通道具有不同的动力学特性，通常与神经元的单峰或爆发性活动相耦合。此外，VGLUT3和Vacht如何影响彼此的囊泡分选尚不清楚。 在这种背景下，我们提出了两个主要任务：i)确定哪些突触蛋白，如突触集聚蛋白或钙通道与Vacht或VGLUT3阳性的SVS有关；ii)阐明Vacht或VGLUT3如何影响彼此的突触靶向。 这项研究的主要成果将是更好地了解TANS，这是一个具有独特性质的关键神经元群体。这些知识将推动对纹状体功能的研究，如运动活动、习惯或奖励引导行为。因此，帕金森氏症、强迫症或成瘾等各种病理疾病都可以从我们的研究中发现的基本知识中受益。

Neurons communicate with electrochemical signals. Chemical messengers, or neurotransmitters, are accumulated inside synaptic vesicles (SV) before their calcium-dependent release. Glutamate (glut) the major excitatory transmitter in the brain is concentrated inside SV by vesicular transporter named VGLUT1-3. Our team made the surprising discovery that VGLUT3 is expressed by neurons using other neurotransmitters than glutamate. VGLUT3 is present used by all striatal cholinergic interneurons (also named Tonically Active Neurons or TANS). Therefore, TANS signal with both acetylcholine (ACh) and glut. The consequences of ACh/glut cotransmission recently started to be investigated. For example, we established that VGLUT3 null mice are hyperactive and more sensitive to cocaine. This is essentially due to an increased dopamine signaling in the nucleus accumbens in the absence of VGLUT3. Interestingly, silencing ACh signaling in TANS by specific ablation of the vesicular ACh transporter (VAChT) has opposite effects. Therefore, the dual ACh/glut transmission provides TANS with complex regulatory properties of striatal networks. We recently observed that VAChT or VGLUT3 are sorted to different populations of SVs in TANS. The objective of our proposal is to better understand molecular mechanisms underlying the vesicular sorting of VAChT or VGLUT3 in TANS. This will help to identify original molecular targets involved in the regulation of striatal networks. In particular, different types of calcium channels (L, N, P, and Q channels) critically regulate neurotransmitter release. These calcium channels have different kinetics properties and are often coupled to either single spike or bursting activity of neurons. In addition, nothing is known on how VGLUT3 and VAChT influence each other vesicular sorting. In this context, we propose 2 major tasks: i) to identify which synaptic proteins such as synaptotagmins or calcium channels associated with VAChT- or VGLUT3-positive SVs and ii) to clarify how VAChT or VGLUT3 impact on each other synaptic targeting. The major outcome of this research will be a better understanding of TANS, a pivotal neuronal population with unique properties. This knowledge will fuel research on striatal functions such as locomotor activity, habits- or reward-guided behaviors. Therefore pathologies as diverse as Parkinson's disease, obsessive-compulsive disorders or addiction could benefits from basic knowledge that will emerge from our investigations.