Simultaneous monitoring of action potentials and neurotransmitter release from neuron-like PC12 cells.

Simultaneous recording of action potentials (APs) and neurotransmitter release is highly desirable in living neurons since it provides a complete framework of the physiological and pathological statuses of nerve cells. In this work, we proposed an approach coupling ultra-thin microelectrode array (MEA) with total internal reflection fluorescence microscopy (TIRFM), which served as a powerful platform to visualize both APs and vesicular exocytosis in a neuronal circuit model formed by neuron-like PC12 cells. Taking advantages of fluorescent false neurotransmitter (FFN), the transient neurotransmitter transport down an axon could be visualized with high spatial and temporal resolution. The real-time recording of APs burst and neurotransmitter release induced by hypoxia with MEA/TIRFM platform reveals the relevance of electrical and chemical activities in the neuronal model. The combination of the optical and electrical techniques enables mapping of neuron connectivity in an entire neuronal circuit, which may ultimately lead to deeper understanding of nervous system.