Poster Presentation 2014 International Biophysics Congress

A novel small-and-fast exocytosis process revealed by amperometry (#448)

Ren Hu 1 , Bin Ren 1 , Chang-Jian Lin 1 , Christian Amatore 2 , Zhong-Qun Tian 1
  1. State Key Laboratory of Physical Chemistry of Solid Surfaces and LIA CNRS XiamENS, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, China
  2. UMR CNRS-ENS-UPMC 8640 “PASTEUR” and LIA CNRS XiamENS, Département de Chimie, École Normale Supérieure, Paris, France
Regulated exocytosis of neurotransmitters exhibits characters of small release quantity (amol) and fast process (ms), which pose high challenges for its detection. Amperometry at carbon fiber microelectrodes is perfectly suited to monitor vesicular exocytotic processes at the single cell level due to its high sensitivity and appropriate temporal resolution. In this work, the time dependence of catecholamine vesicular exocytosis from PC12 cell under repeated high potassium stimulations was investigated by amperometry. It was found that after 20 min of stimulation, a group of small exocytosis spikes (less than 8 pA) emerges and becomes gradually prominent in the following responses. These small spikes exhibit significantly faster dynamics than that of the majority. This fast dynamics can be attributed to swift opening and closing of the fusion pores. The mechanism underlying this small and fast exocytosis phenomenon will be discussed.