Simultaneous "real-time" electrochemical and electrophysiological recording in brain slices with a single carbon-fibre microelectrode.

Many previous studies have demonstrated the value of carbon-fibre microelectrodes (CFMs) for single-unit activity recording and for fast cyclic voltammetry. In this report we show that these two independent methodologies can be combined at a single CFM and used to study simultaneous electrochemical and electrophysiological events in brain slices. In superfused slices of rat locus coeruleus, dorsal raphe and substantia nigra, we were able to record stable electrophysiological signals and stimulated monoamine efflux for periods of at least 2 h, thereby allowing quantitative pharmacological interventions. The simultaneous recording of amine efflux and unit activity at the same locus facilitates comparison of drug effects at pre- and post-synaptic sites. Furthermore, the system described here uses commercially available instrumentation. The circuitry is described and examples of its application are shown.