(full paper is archived in the Miller Library)
Title: Electrochemical detection of neurotransmitters with carbon-fiber microelectrodes
Student Author(s): Matheson, Angus
Faculty Advisor(s): Thompson, Stuart
Location: Final Papers Biology 175H
Date: June 1992
Abstract: Carbon-fiber microelectrodes were used to electrochemically measure concentrations of oxidizable neurotransmitters, serotonin, epinephrine, and norepinephrine. The electrodes consisted of a carbon filament surrounded by a glass capillary tube. The carbon filament was connected to a patch clamp amplifier to set the filament at a certain voltage and measure current flow, which increased during oxidation. This was done both with a triangle wave, cyclic voltammetry, and a set potential of +.5 and .6V, amperometry. Calibration curves were done with known concentrations of both epinephrine and serotonin in vitro. In vivo recording were performed in Pleurobranchea pedal ganglion and N1E-115 Neuroblastoma cells. Epinephrine behavior was close to theory with a one to one relation between increase in I and [Epi], but the response to [5-HT] was not as strong. The electrodes measured 90 uM (400 pA by amperometry) release of serotonin from the Pleurobranchea pedal ganglion. Readings were also taken from N1E-115 cells which showed 1 to 100 uM (1.6nA) norepinephrine release after stimulation with carbachol, a non-oxidizable analog of acetylcholine.