In multicellular organisms, cellstypically communicateby sendingand receiving chemical signals. Chemical messengers involved in theexocytosis of neuroendocrine cells or neurons are generally assumedto only originate from the fusing of intracellular large dense corevesicles (LDCVs) or synaptic vesicles with the cellular membrane followingstimulation. Accumulated evidence suggests that exosomes oneof the main extracellular vesicles (EVs)carrying cell-dependentDNA, mRNA, proteins, etc., play an essential role in cellular communication.Due to experimental limitations, it has been difficult to monitorthe real-time release of individual exosomes; this restricts a comprehensiveunderstanding of the basic molecular mechanisms and the functionsof exosomes. In this work, we introduce amperometry with microelectrodesto capture the dynamic release of single exosomes from a single livingcell, distinguish them from other EVs, and differentiate the moleculesinside exosomes and those secreted from LDCVs. We show that, similarto many LDCVs and synaptic vesicles, exosomes released by neuroendocrinecells also contain catecholamine transmitters. This finding revealsa different mode of chemical communication via exosome-encapsulatedchemical messengers and a potential interconnection between the tworelease pathways, changing the canonical view of exocytosis of neuroendocrinecells and possibly neurons. This defines a new mechanism for chemicalcommunication at the fundamental level and opens new avenues in theresearch of the molecular biology of exosomes in the neuroendocrineand central nervous systems.
