Dopamine (DA) plays a critical role in the brain, and the ability to directly measure dopaminergic activity is essential for understanding its physiological functions. We therefore developed red fluorescent G-protein-coupled receptor-activation-based DA (GRAB_DA) sensors and optimized versions of green fluorescent GRAB_DA sensors. In response to extracellular DA, both the red and green GRAB_DA sensors exhibit a large increase in fluorescence, with subcellular resolution, subsecond kinetics and nanomolar-to-submicromolar affinity. Moreover, the GRAB_DA sensors resolve evoked DA release in mouse brain slices, detect evoked compartmental DA release from a single neuron in live flies and report optogenetically elicited nigrostriatal DA release as well as mesoaccumbens dopaminergic activity during sexual behavior in freely behaving mice. Coexpressing red GRAB_DA with either green GRAB_DA or the calcium indicator GCaMP6s allows tracking of dopaminergic signaling and neuronal activity in distinct circuits in vivo.

多巴胺 (DA) 在大脑中起着至关重要的作用，直接测量多巴胺能活动的能力对于了解其生理功能至关重要。因此，我们开发了基于红色荧光 G 蛋白偶联受体激活的 DA (GRAB _DA ) 传感器和绿色荧光 GRAB _DA传感器的优化版本。为了响应细胞外 DA，红色和绿色 GRAB _DA传感器均表现出荧光大幅增加，并具有亚细胞分辨率、亚秒级动力学和纳摩尔至亚微摩尔亲和力。此外，GRAB _DA传感器可解析小鼠脑切片中诱发的 DA 释放，检测活果蝇中单个神经元诱发的区室 DA 释放，并报告自由行为小鼠性行为期间光遗传学引发的黑质纹状体 DA 释放以及中伏隔多巴胺能活动。将红色 GRAB _DA与绿色 GRAB _DA或钙指示剂 GCaMP6 共表达，可以跟踪体内不同回路中的多巴胺能信号传导和神经元活动。