Analysis of single-vesicle exocytotic events recorded by amperometry

Analysis of the shape of the amperometric spikes that originate from the oxidation of monoamine molecules released during the fusion of individual secretory vesicles provides valuable data about molecular steps involved in stimulation-dependent transmitter release. The sensitivity of amperometry permits the detection of the monoamines released from individual vesicles, giving information about intracellular transmitter homeostasis (synthesis, degradation, reuptake, etc.) and about the release probability (vesicle availability and sensitivity of fusion machinery to Ca(+2)). Furthermore, temporal resolution of amperometry allows for the observation of the real-time kinetics of monoamine release during exocytosis. Here, we provide algorithms for computerized analysis of the amperometric signal with emphasis on routines that confer consistent determination of spike parameters on recordings with different sampling rates, signal-to-noise levels, spike durations, and surrounding signal.