Amperometric detection of vesicular exocytosis from BON cells at carbon fiber microelectrodes

• Exocytosis of BON cells has been investigated in details by amperometry.
• The BON cells activity is rather weak by comparison with others cell models.
• This low activity represents a potential advantage for TIRFM-amperometry combination.

Amperometry at ultramicroelectrodes is nowadays a routine analytical technique for quantitative real-time monitoring of vesicular exocytosis at single cell levels. The method performance and ease of application stem from the fact that it simply involves an electrochemical oxidation at a microelectrode surface of neurotransmitters released by a given cell. The exocytotic fluxes are thus converted into a current and appear as a succession of amperometric spikes, whose frequency and shapes are particularly informative about the dynamics of the release process, while their integrals give a direct measure of the quantity of molecules released. In this article, we wish to evaluate and describe the amperometric detection of exocytotic release by BON cells, a cell line derived from a metastatic human carcinoid tumor of the pancreas and recently involved in combined approaches of exocytosis (particularly fluorescence/electrochemistry). The whole exocytotic activity (frequency, spike magnitude) of BON cells is rather weak by comparison with those observed with others cell models like chromaffin cells but remain suitable for amperometric investigations.