Chronoamperometry in vivo: does it interfere with spontaneous neuronal activity in the brain?

To test whether chronoamperometry in vivo interferes with spontaneous neuronal activity, chronoamperometric measurements were combined with electrophysiological recordings in the same preparation. Chronoamperometric measurements (0.5--1.0 V applied for 1 s) were taken in the rat corpus striatum and single unit activity was recorded extracellularly in the same area. With potentials of 0.5 V, chronoamperometric measurements did not interfere with spontaneous activity of the striatal neurons, even of those units situated in close proximity (approximately 100 micrometers) to the tip of the electrochemical working electrode. Chronoamperometric measurements at potentials from 0.6 to 1.0 V accelerated or inhibited the firing rates of part of the striatal neurons, even when the electrophysiological circuit was interrupted during the application of the chronoamperometric pulse.