Electroactive fluorescent false neurotransmitter FFN102 partially replaces dopamine in PC12 cell vesicles

In the last decade, following fluorescent dyes and protein tags, pH sensitive false fluorescent neurotransmitters (FFN) were introduced and were valuable for labeling secretory vesicles and monitoring exocytosis at living cells. In particular, the synthetic analog of neurotransmitters FFN102 was shown to be an electroactive probe. Here, we show that FFN102 is suitable to be used as a bioanalytic probe at the widely used PC12 cell model. FFN102 was uptaken in the secretory vesicles of PC12 cells, partially replacing the endogenous dopamine stored in these vesicles. The different oxidation potentials of dopamine and FFN102 allowed to determine that ca. 12% of dopamine was replaced by FFN102. Moreover, the FFN102 was found to be over released through the initial fusion pore suggesting that it was mostly uptaken in fast diffusion compartment of the vesicles.