Spatial mapping of receptor distributions on single identified neurons

 描述(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节剂在功能上重新配置神经元电路，并允许灵活而稳定的行为输出(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活动。这项拟议的工作在甲壳类动物的口胃神经节(STG)中解决了这个问题，STG是一种包含26-30个大型、可识别的、具有复杂形态的神经元的小型运动电路。所有的STG神经元都对GABA(Swensen等人，2000)和谷氨酸(Marder&Paupardin-Tritsch，1978；Cleland&Selverston，1998)都有反应。GABA和谷氨酸离子亲电受体的亚细胞分布，以及它们所在的隔室的电特性，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。这些神经元可能不同地共同调节和表现出离子刺激受体的刻板空间分布，这些受体分布有助于它们独特的放电特性。这 假说将使用一个定制的光学系统，用于焦点光激活和跨不同STG神经元类型的结构的离子型GABA和谷氨酸反应的映射。这些图谱将与mRNA表达研究相辅相成，以确定对这两种配体的敏感性是以隔室特有的方式还是以神经元范围的方式共同调节。最后，这些图谱将被用来作为一个框架，以了解面对调制扰动时亚细胞受体分布的功能相关性。以前的工作表明，多巴胺改变了STG神经元中谷氨酸受体的敏感性(Cleland&Selverston，1997；Johnson&Harris-Warrick，1997)。谷氨酸受体的局部光激活与空间和时间控制的离子导入多巴胺给药相结合，将被用来探索这种谷氨酸敏感性的调制变化是通过均匀还是异质地调节单个神经元结构中不同的亚细胞谷氨酸受体基因来发生的。

 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.