Exocytosis is the process in which the contents of secretory vesicles are released by their fusion to the plasma membrane and plays a vital role in signaling of the nervous and endocrine system. Exocytosis can be detected by several physical and chemical means. By chemically oxidizing the released secretory products at a fixed electrode potential, carbon fiber amperometry provides excellent temporal and spatial resolution in detecting exocytosis. Among the most intensively studied products include, norepinephrine, epinephrine, dopamine, and serotonin. ALA can provide full systems suitable for recording this process. The VA-10 amplifier is a sensitive (picoampere range) current amplifier that is specifically designed for voltammetric and amperometric measurements with carbon-fiber microelectrodes in biological systems. It was designed at the Max-Planck-Institute for Experimental Medicine in Göttingen as an economically priced alternative to do-it-yourself systems and expensive commercial systems.

It can be used for either DC amperometry using the built-in voltage source, or it can be operated with user-supplied external voltage waveforms (e.g. for cyclic voltammetry). The VA-10X is ideally suited for measurements from single cells plated onto glass cover slips and with carbon-fiber disk electrodes having diameters of 10 µM or less. Carbon fibre electrodes, CFE-1, are hand made at ALA Scientific Instruments and individually tested to ensure viability.

Equipment:

• npi VA-10 amplifier
• Instrutech ITC-18 data acquisition card
• HEKA PatchMaster
  
• KS 9100 series table