Automatic analysis for amperometrical recordings of exocytosis

Abstract

Amperometry is a widely used technique for monitoring the secretion of catecholamines (CA) by exocytosis. The use of carbon fibre microelectrodes allows the on-line recording of CA released from a single secretory vesicle. Amperometric signals are generated by oxidation of the quantally released CA close to the electrode tip. Each event of exocytosis is called a secretory spike. Here we describe a program written for IGOR (Wavemetrics, Lake Oswego, OR, USA), which may be used to analyze amperometric signals off-line. The procedures allow, (i) digital filtering and analysis of the current noise, spike identification and calculation of spike kinetic parameters; (ii) spike review; (iii) pooling spikes and data to create galleries, tables and histograms of measured parameters which can be exported to a graphic format or files for further analysis.