Interpretations of Voltammetry in the Striatum Based on Chromatography of Striatal Dialysate

Abstract

Abstract A comparison is made of chronoamperometric data recorded from the striatum and chromatographic data obtained from extracellular striatal perfusate. Three specific cases are considered: the initial sampling period in which a decline in the observed oxidation current occurs; the effect of haloperidol, a dopamine receptor blocker; and the effect of amphetamine. The perfusate is analyzed for ascorbic acid (AA), the dopamine metabolites dihydroxyphenylacetic acid (DOPAC) and homovanillic acid (HVA), and the serotonin metabolite 5-hydroxyindoleacetic acid (5-HIAA). Using the relative response of these compounds at a carbon epoxy or carbon paste electrode, and the relative concentration of each in the extracellular fluid, the expected changes in oxidation currents for the three cases mentioned above are calculated. It is shown that the decline in oxidation current during the initial sampling period is due primarily to a decrease in ascorbic acid. It is also shown that different electroactive components of the extracellular fluid are the cause of changing oxidation currents under different stimulus conditions.