Semi-differential voltammetry with carbon fiber electrodes for in vivo determination of monoamine metabolites and ascorbic acid in rat corpus striatum

Carbon fiber electrodes combined with semi-differential voltammetry were used to determine endogenous monoamine metabolites and ascorbic acid (AA). These electrodes treated by a new electrochemical procedure (30 microA for 30 s, then -2 V for 10 s) showed a significant improvement on the sensitivity and selectivity. In the rat corpus striatum, these electrodes allowed a distinct separation and continuous detection of AA, 3, 4-dihydroxyphenylacetic acid (DOPAC), and 5-hydroxyindoleacetic acid (5-HIAA) simultaneously. The normal striatal levels of AA, DOPAC, and 5-HIAA were found to be 168.2 +/- 19.5, 21.4 +/- 3.9, and 3.3 +/- 0.5 mumol.L-1. Our method is credible for detecting the changes of monoamine metabolite contents induced by pharmacologic manipulations.