Electrochemical imaging of neurotransmitter release with fast-scan voltammetric ion conductance microscopy.

Understanding the dynamic spatial and temporal release of neurotransmitters can help resolve long-standing questions related to chemical modulation of neurological circuits. Dopamine modulates function in a range of physiological processes and is key to transmission in addiction and neurological disorders. Studies at subcellular scales promise to help develop a broader understanding of dopamine release, diffusion, and receptor activation and how these processes lead to functional outcomes. Electrochemical measurements of dopamine release at individual cells have proven especially informative. We describe incorporation of fast-scan cyclic voltammetry for detection of dopamine release with subcellular spatial resolution and millisecond time resolution. The platform is benchmarked with standard redox probes and then applied to imaging stimulated release from subcellular locations of a coculture of dopaminergic neurons and astrocytes. Voltammetry reveals heterogeneity in release based on time, location, and neuron identity. We believe that this platform ultimately offers a window to understanding neurotransmission in pathophysiological models of disease where cell-cell communication is key.