纹状体通过直接与间接通路精确调控运动的时机与强度。传统观点认为间接通路主要发挥抑制运动的作用,但近年来研究表明, 不同行为背景下, 间接通路中表达多巴胺D2受体的中型多棘神经元(D2-dopamine receptor-expressing medium spiny neurons,D2-MSNs)可对运动产生促进或抑制的双向调控作用。本文首先从运动启动、速度调节、习惯形成及回避行为等多个方面, 阐述了D2-MSNs对运动的多样性调控功能; 其次从该类神经元上受体分布的特点、与其他中间神经元的交互作用以及下游神经环路三个层面, 分析了D2-MSNs调控运动的机制; 最后, 探讨了D2-MSNs在多种运动障碍疾病中的作用,以期深化对D2-MSNs在基底节运动调控中功能的理解, 并为相关疾病的精准治疗提供新思路。

The striatum orchestrates the timing and vigor of movement through its direct and indirect pathways. The indirect pathway has been viewed as primarily suppressing motor output traditionally. However, recent studies indicate that dopamine D2 receptor-expressing medium spiny neurons (D2-MSNs) within the indirect pathway can either facilitate or inhibit behavior depending on context, thus exerting bidirectional control over movement. Accordingly, this review first synthesizes evidence on the diverse regulatory functions of D2-MSNs across multiple domains of motor control, including movement initiation, speed regulation, habit formation, and avoidance. It then examines the mechanisms by which D2-MSNs regulate movement at three levels: the characteristic patterns of receptor distribution on these neurons, their interactions with other striatal interneuron populations, and the organization of downstream neural circuits. Finally, the significance of D2-MSNs in various movement disorders is considered, in order to refine understanding of their role within basal ganglia models of motor control and to inform more precise therapeutic strategies for movement disorder-related conditions.