Spatial mapping of receptor distributions on single identified neurons

 描述（由申请人提供）：大脑受多种氨基酸、胺和神经肽的作用。这些局部神经递质和弥散神经调质在功能上重新配置神经元回路，并允许灵活但稳定的行为输出（Marder，2012）。调节和递质系统的功能障碍与许多精神和神经疾病有关。为了了解健康的大脑如何调节这种动态的化学环境，我们必须首先了解单个神经元如何调节许多信号分子的作用。拟议的工作解决了这个问题，在甲壳类动物的口胃神经节（STG），一个小的运动电路，包含26-30个大的，可识别的神经元与复杂的形态。所有的STG神经元都对GABA（Swensen et al.，2000）和谷氨酸（Marder & Paupardin-Tritsch，1978; Cleland & Selverston，1998）。GABA和谷氨酸离子型受体的亚细胞分布，以及它们发挥作用的隔室的电特性，可能决定了这些配体影响单个STG神经元的放电特性的权重。这是合理的，这些神经元差异共调节，并表现出刻板的空间分布的离子型受体，这些受体分布有助于其独特的放电特性。这 假设将使用定制光学系统进行局灶性光激活和跨不同STG神经元类型的结构的离子型GABA和谷氨酸响应的映射。这些图谱将用mRNA表达研究补充，以确定对这两种配体的敏感性是否以区室特异性或神经元范围的方式共调节。最后，这些地图将被用来作为一个框架，了解功能相关的亚细胞受体分布在面对一个调制扰动。先前的工作已经表明多巴胺改变STG神经元中的谷氨酸受体敏感性（Cleland & Selverston，1997;约翰逊& Harris- Warrick，1997）。谷氨酸受体的局灶性光活化与空间和时间控制的离子电渗多巴胺给药串联将被用来探测谷氨酸敏感性的这种调节变化是否通过均匀或不均匀地调节单个神经元结构中的不同亚细胞谷氨酸受体位点而发生。

 DESCRIPTION (provided by applicant): The brain is subject to the action of numerous amino acids, amines, and neuropeptides. These local neurotransmitters and diffuse neuromodulators functionally reconfigure neuronal circuitry and allow for flexible, yet stable, behavioral output (Marder, 2012). Dysfunction of modulatory and transmitter systems has been implicated in a number of psychiatric and neurological disorders. In order to understand how the healthy brain mediates this dynamic chemical milieu, we must first understand how single neurons mediate the action of many signaling molecules. The proposed work addresses this question in the crustacean stomatogastric ganglion (STG), a small motor circuit containing 26-30 large, identifiable neurons with complex morphologies. All STG neurons are responsive to both GABA (Swensen et al., 2000) and glutamate (Marder & Paupardin- Tritsch, 1978; Cleland & Selverston, 1998). The subcellular distribution of GABA and glutamate ionotropic receptors, and the electrical properties of the compartments in which they function, likely dictates the weights with which these ligands influence the firing properties of single STG neurons. It is plausible tha these neurons differentially co-regulate and exhibit stereotyped spatial distributions of ionotropi receptors, and that these receptor distributions contribute to their unique firing properties. This hypothesis will be addressed using a custom optical system for focal photo-activation and mapping of ionotropic GABA and glutamate responses across the structures of different STG neuron types. These maps will be complemented with mRNA expression studies to determine if sensitivities to these two ligands are co-regulated in a compartment-specific or neuron- wide manner. Lastly, these maps will be used as a framework for understanding the functional relevance of subcellular receptor distributions in the face of a modulatory perturbation. Previous work has shown that dopamine alters glutamate receptor sensitivity in STG neurons (Cleland & Selverston, 1997; Johnson & Harris- Warrick, 1997). Focal photo-activation of glutamate receptors in tandem with spatially and temporally controlled iontophoretic dopamine administration will be used to probe whether this modulatory change in glutamate sensitivity occurs by uniformly or heterogeneously modulating different subcellular glutamate receptor loci across the structure of single neurons.