Selective modulation of basal ganglia circuits

帕金森病（PD）是基底神经节的神经退行性疾病，其中在黑质中存在含多巴胺的神经元的损失，所述神经元投射到壳核和尾状核（纹状体）。当纹状体中多巴胺能神经支配的损失达到临界水平时，运动症状如震颤、僵硬和运动迟缓变得明显。PD动物模型的可用性导致了对基础回路的高度理解，并强调了两个平行的纹状体流出通路（称为“直接”和“间接”通路）中神经元活动的重要性。在帕金森病状态下，这些通路的相对活性受到干扰。这项建议探讨了新的技术，旨在差异控制活动，在这两个途径使用基因转移载体，改变神经元的兴奋性。基于疱疹病毒或腺病毒的病毒载体将被构建并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该通道调节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）确定是否可以利用大鼠壳核神经元的原代分散培养来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转导属于间接或直接壳输出途径的细胞，和（3）开发和测试基因转移载体，该载体被设计为选择性地增强属于直接或间接输出途径的基底神经节神经元中的K+通道活性。该提案的成功完成将允许进一步开发用于PD对症治疗的基因疗法。

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.