Selective modulation of basal ganglia circuits

帕金森病(PD)是一种基底节神经退行性疾病，黑质中含有多巴胺的神经元丢失，投射到壳核和尾状核(纹状体)。当纹状体中多巴胺能神经的丧失达到临界水平时，运动症状如震颤、僵硬和迟缓运动变得明显。帕金森病动物模型的建立提高了对基础回路的认识，并强调了纹状体流出通路中神经元活动的重要性，这两条通路被称为“直接”和“间接”通路。在帕金森氏症状态下，这些通路的相对活动受到干扰。这项建议探索了新的技术，旨在使用改变神经元兴奋性的基因转移载体来差异控制这两条通路的活动。将构建以疱疹病毒或腺病毒为基础的病毒载体，并将其用于增强培养的大鼠纹状体神经元电压门控性钾通道的活性。单细胞电生理学和免疫细胞化学将被用来监测这种通道调节对与直接或间接途径相对应的特定细胞类型的影响。这项建议的具体目的是：(1)确定是否可以利用分散的大鼠壳核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间接或直接壳核输出通路的细胞；以及(3)开发和测试一种基因转移载体，旨在选择性地增强直接或间接输出通路的基底节神经元的K+通道活性。这项提议的成功完成将使帕金森病的对症治疗的基因疗法得到进一步发展。

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.