The carbon fiber electrode and its application for detecting neurohormones

Quantal release of neurohormones from single cells can be detected by the electrochemical method of amperometry. Single release of catecholamines from chromaffin cells was recorded as current spikes using an improved carbon fiber electrode (CFE). The fabrication of CFEs is also described. The measurement system consisted of an EPC-9 patch clamp amplifier, a data acquisition device, some relevant software and a computer system. In experiments primary cultured chromaffin cells were used. Cells were stimulated with 60 mM KCl, and the current spikes recorded with a pulse width of 1-20 ms and an amplitude of 20-200 pA. Each spike corresponded to the quantal release of one vesicle under the surface of the CFE´s tip