Selective modulation of basal ganglia circuits

帕金森病（PD）是一种基底神经节的神经退行性疾病，其中黑质中含有多巴胺的神经元丢失，这些神经元投射到壳核和尾状体（纹状体）。当纹状体中多巴胺能神经支配的丧失达到临界水平时，运动症状如震颤、强直和布律性运动就会表现出来。PD动物模型的可用性提高了对基础电路的理解，并强调了两条平行纹状体流出通路（称为“直接”和“间接”通路）中神经元活动的重要性。在帕金森状态下，这些通路的相对活性受到干扰。本研究旨在探索利用改变神经元兴奋性的基因转移载体对这两种通路进行不同控制的新技术。本文将构建基于疱疹病毒或腺病毒的病毒载体，用于增强培养的大鼠纹状体神经元的电压门控钾通道活性。单细胞电生理学和免疫细胞化学将用于监测这种通道调制对直接或间接途径对应的特定细胞类型的影响。本研究的具体目的是：(1)确定是否可以利用分散的大鼠壳层神经元原代培养建立一个有用的基底神经节回路模型系统；(2)确定使用细胞特异性启动子的病毒基因转移载体是否能够选择性地转导属于间接或直接皮膜输出通路的细胞；(3)开发和测试旨在选择性地增强属于直接或间接输出通路的基底神经节神经元K+通道活性的基因转移载体。这一建议的成功完成将允许进一步开发一种用于PD症状治疗的基因疗法。

Parkinson's Disease (PD) is a neuro-degenerative disorder of the basal ganglia in which there is a loss of dopamine-containing neurons in the substantia nigra, which project to the putamen and caudate (striatum). When the loss of dopaminergic innervation in the striatum reaches a critical level, motor symptoms such as tremor, rigidity, and brady kinesia become manifest. The availability of animal models of PD have led to a heightened understanding of the basal circuitry, and underscored the importance of neuronal activity in two parallel striatal outflow pathways termed the "direct" and "indirect" pathway. The relative activity of the pathways is disturbed in the Parkinsonian state. This proposal explores novel techniques aimed at differentially controlling activity in these two pathways using gene transfer vectors that alter neuronal excitability. Viral vectors based on herpes virus or adenovirus will be constructed and used to augment the voltage-gated potassium channel activity in cultured striatal neurons from rat. Single-cell electrophysiology and immunocytochemistry will be used to monitor the effects of this channel modulation on defined cell types corresponding to the direct or indirect pathway. The specific aims of this proposal are: (1) to determine whether of a useful model system of basal ganglia circuitry can be developed using dispersed primary cultures of rat putaminal neurons; (2) to determine whether viral gene transfer vectors using cell-specific promoters are capable of selectively transducing cells belonging to the indirect or direct putaminal output pathways, and (3) to develop and test a gene transfer vector designed to selectively augment K+ channel activity in basal ganglia neurons belonging to either the direct or indirect output pathways. Successful completion of this proposal would allow further the development of a gene therapy for the symptomatic treatment of PD.