Protocol for fluorescent false neurotransmitter live imaging of dopamine release dynamics from individual synapses in acute brain slices.

Striatal dopaminergic (DA) axons have many en passant boutons with synaptic vesicles, but only a fraction display exocytosis. Here, we present a protocol for live imaging of murine DA axons using fluorescent false neurotransmitter 200 (FFN200), a vesicular monoamine transporter 2 (VMAT2) substrate accumulated by and released from DA synaptic vesicles, providing spatial and temporal kinetics of exocytosis. We describe steps for preparing mouse acute brain slices, loading slices with the FFN, acquiring images with 2-photon microscopy, and analyzing the data. For complete details on the use and execution of this protocol, please refer to Hwu et al.1.